If you wonder how this actually takes place, here it is. The MRI is a Dewar's container, at as close to absolute vacuum as possible on earth. It is layered round and round inside the tank with Mylar silver sheeting, which is a supreme barrier to heat in the radiant spectrum, for even further insulation (radiant heat will absolutely pass through a vacuum, or the sun would never heat the earth!!!). Just the warmth of the outside of the MRI tank will "radiate" heat inward inside the tank and this too has to be stopped. The vacuum will stop "conductive" heat transfer. NOW if that vacuum is compromised in ANY way the 1000 liters of liquid HE will boil SO FAST you can not imagine how quickly that will occur!!! The heat in the room will go through that compromised tank like LIGHTNING and boil most of it off in SECONDS!! IN FACT if the tank did NOT have a burst disc, the whole tank would EXPLODE with the violence of an exploding BOILER or a BUNDLE of dynamite!!! NOW FOR THE FUN FACT!! When the guy pushes the red button, it turns on a heater element (like a room heater or bread toaster) deep inside the tank. That blast of heat will cause cause a furious boiling of the liquid HE and the tank pressure will rise ENORMOUSLY!!! The burst disc will fail from pressure and the helium will roar out of that big opening into a vent pipe and outside the building. Once outside, the cold helium gas will condense all the humidity in the air and cause a huge CLOUD of frozen water vapor, just like in the sky!!.....................The MRI (if it is not being replaced) is now going to have to go through a terribly expensive process to re-install a vacuum in the tank and then to re-introduce liquid HE back in- this is called ramping up....................But, if you took a power drill and drilled, say, a half-inch hole through the outside of a live and functional MRI tank, you would first hear a loud sucking noise as the vacuum was lost. Moments later the MRI would go "nuts" inside with the boiling helium and it would rupture the burst disc and discharge the same way it would if you quenched it, just a little slower before it vented, BUT NOT MUCH!!! That is HOW FAST the heat would get inside the tank once the vacuum is gone!!!!
@Paul Flusk Some MRIs do exactly that. The cold-head recirculates the HE to keep it in a liquid state. In ones like the older Oxford are dual-cryogenic, and use liquid N2 in a layer between the inner magnet tank and the outer shell and use the "sacrificial" refrigerant effect to help maintain the extreme cold needed to keep the HE liquid. The temp needed to do that is on the order of MINUS 450 degrees, near absolute zero, the temp in deep space. In mid 2008, I scrapped one of these and 2 smaller ones, and after expenses, I put 47,000 dollars in my pocket in 3 days work! One of the best hits I ever made in the scrap business!!
@@tokenlau7519 You do 'got" me on that one!! The way I wrote it would more imply High Explosive round like a tank shell! I never noticed when I wrote it, unless I kept my hand on the shift key too long!!
@@Patrick-zr8tv When the college of cardinals chooses a new pope they release white smoke into the air by burning the cast ballots to signal to the world a new pope has been chosen. If a vote is cast and none of the candidates receive 2/3rds of the votes then black smoke is released by burning the cast ballots with a substance that turns the smoke from white to black. Then the cardinals debate and hold another vote. Hope this clears it up for you.
Never seen an MRI like that before, very cool to watch. Used to clean in a couple hospitals, and dusting/cleaning around these was always a fun way to spook coworkers and even getting spooked myself a few times. I was working 3rd shift, the area was shut down and not in use at night in the children's hospital. I was in the room by myself mopping. As I mopped closer to the MRI, I felt something tugging the back of my bra and then the underwires. I spin around about to chew someone out for creeping on up on and realize the MRI was just being pervy.
Im a guy, but i take you as a superhero. I couldn't bear a single minute alone, at night inside a hospital Mosty because my undermind is filled with creepy stuff But at least you made me laugh when you said that MRI was being pervy on you
@@professional6513 Lol, glad I could make you smile! Most of the hospital was still well lit even at night (if you get admitted, bring an eye mask). I only had a couple of spooky/creepy moments while I worked there. The one area was the recovery for children after surgery; that gets shut down completely at night. Heard a baby crying in one of the recovery rooms at 3AM. The other was in an area that had light patient traffic. Was cleaning in adult radiology, one of the PET scan rooms and something just felt off, like the hairs raising up on the back of your neck. Never saw anything, but speaking to a radiologist later during a break, they told me of the resident ghost in that area that likes to knock clocks off the walls. Gross job, but it was really fascinating.
@@tekvax01 I was working late by myself at my desk in the Clinical Engineering Lab of a very large hospital. I looked up from my desk and saw a young boy who looked just fine standing in the doorway to the Lab. I asked him if he was lost and he smiled and shook his head. I then asked if I could walk him back to find his parents somewhere, again without a word he just kept smiling and shook his head. I said, "Ok, well have a nice night" he smiled and turned around and walked out of the door. About five seconds later, I decided that I would help him anyway, that he must be lost. Our Lab was at least 100 yards from any patient care facilities down a long door-less corridor. When I got to the door and looked down the hall he was nowhere in sight. I ran as fast as I could down the hall to try to catch him but never saw him again. There is no way a young boy could have made that distance in the 5 seconds it took me to get to the door. I knew then that it as something else. I always thought I would be scared poopless if i saw a ghost. However it was actually a calming and very pleasant experience.
@@quicksc1 Wow! I've never seen one or had an experience before, but I know several people that have... Some have been harmless like yours, whilst others, downright scary... If I ever do, I hope mine is the former and not the latter... .
^ This! ^ -- MRIs are to magnetic fields as Tesla coils are to electric fields. However, the gradient must also be considered, and the gradient - not just the absolute field intensity - is "worst" closest to the magnet.
Even so, I have "non-magnetic" piercings... and I treasure my phone and can't afford to buy new ones casually so... yeah, i wouldn't get within ten feet of the door to the magnet room without stripping _completely_ naked, _sans_ornement_.
I've accidentally taken my phone into 7.05 Tesla magnetic fields before. If I got too close it would turn off. However, it had no effect at about 5 feet away where the field strength was indicated to be 5 Telsa. Considering this MRI only has a 0.7 T magnet, if you are even 3 feet away your phone should not have any issues. When people start out working around strong magnets they get paranoid about metal, but as it turns out most metal on us (keys, rings, etc) are diamagnetic.
Yeah there is a difference if our phones had hard drives then every time you would drop your phone it would mess up the hard drive more and more eventually rendering the information on the hard drive useless and deleted, same happens if you bang around your laptop if it has a hard drive
@The Mini Machinist Some solid state devices are affected. An acquaintance of mine works in a medical field and his hearing aids were destroyed when he went into an MRI room to assist with patient care. I don't know if the machine was actively scanning. The RF energy injected into the magnetic field can mess with electronic circuitry, not just magnetic storage media.
@@tlw2585 Quenching refers to the sudden loss of liquid helium from a superconducting electromagnet. The loss of liquid helium raises the temperature of the electromagnet's field coils above that which they are no longer superconducting. The increased resistance generates heat which quickly boils off the liquid helium along with the liquid nitrogen surrounding it. A quench event may result in irreparable damage to the electromagnet.
@@MrHack4never were not really "running out" of helium like you would think we are. We still have plenty to fill all the party balloons you want to lol.
One m.r.i. can contain 10,000 lieters of liquid helium, aka 7.5 million liters of helium gas, about 17,500,000 party balloons if i did my math right. Per quench. This is a upper limit but it shows just how much it wastes. On the other hand there is no feasible way to recover it, as it is extremely difficult to transport. However at around $35,000 of just the cost of liquid in the us and outside up to $150,000 is worth a fair amount. I would personally find a way to recover it, even if it cost 10k per, if i make 30k it would be worth a lot of setup. That said it boils at 6 kelven and air liquifies at 84 kelvin. It takes a lot of specialized equipment to store let alone recover. One of the reasons it is so exspencive.
Believe it or not, the circuit that does this is literally just a 9v battery with a little coil that heats up. That little bit is enough to push the liquid helium well past the point of blowing the vent cap. Pretty cool.
Fascinating that it's not just a venting solenoid or switch that opens a valve to atmosphere. Vacuum envelope or not, you vent that helium to atmosphere as a liquid it's gone either way.
@@RobertMorgan I think breaking the vacuum would make the helium vaporize and expand so violently that the not so large quench vent wouldn't let enough of it out fast enough and the whole magnet would end up exploding like if the quench vent wasn't even there. Look up for Travis Sylvester MRI explosion in the serach bar of this website and you'll find a video where they do eaxctly that: Pulling the cap off the vacuum jacket (Using quite a long rope to be safe 😂😂) and then BOOM !
@@psirvent8 You better believe you're right!! I have pulled those plugs out of the "hole" they are in. Vacuum really is all that is holding this plug in. A good yank will remove it! You should hear the screech of the air rushing into that hole! If there was a lot of liquid helium still inside, it could and probably would blow up the tank! An old dual-cryo unit like an early Siemens with bolted end domes would be a REALLY good candidate for a blast! The welded ones would fail at the inner seam of the bore tube to end plate weld! One time I had a liquid oxygen Dewar in my truck and knocked the liquid level gauge off under a motel canopy, and the roar of the expanding oxygen caused the people in the office to rush out in panic and call 911!!! And that wasn't even a compromised vacuum situation! Just the hot air near the top of where it broke off was enough for the liquid to go nuts!!
@@junkdealActually I might have been a lil' bit wrong, as I did ask Travis Sylvester about the explosion and he actually told me that the quench vent had been capped before the video, for the sole purpose of blowing the vessel up just for fun. He also said that a properly working quench vent should be able to prevent an explosion even if the vacuum plug were to be taken off. Still the emergency button doesn't affect the vacuum but activates small heater deep within the superconducting windings to make them heat up and vaporize the helium.
Yeah!!!! Some years ago I bought a junker fuel tanker that hadn't been started in a couple years, and when I stepped on the pedal, it was raining straw and baby birds out of the shotgun stack!!!
Inside a MRI machine is a superconducting magnet with some hefty current circulating in it. It creates a very strong magnetic field needed for the imaging. The more the merrier, but also more dangerous. The magnet is cooled by liquid helium (4 K −269 °C −450 °F). The emergency quench button disrupts the current, causing the magnetic field to disappear, but this also resleases the substantial amount of energy stored in the current, which dissipates as heat boiling off the liquid helium. A quench is also a failure mode in superconducting magnet where the conductor loses its superconductor property, the current in a coil suddenly sees a resistance and a voltage spike occurs due to induction law. Again the stored energy gets dissipated by heating stuff and boiling off the helium.
For anyone wondering what's happening, here is the basic rundown. The magnet is so powerful because it's cooled by extremely cold helium. When the EMERGENCY button is pushed the really cold helium is released and magnet stops.
An important point: It's a massive electromagnet, cooled to superconducting temperatures. This means than once the magnet is powered, it's unstoppable until that cooling is removed and it heats back up. There is no turning an MRI magnet on or off, once it's electromagentized as a superconductor, it has zero resistance.
I'm a retired BMET and never got the opportunity to install or de-install an MRI. We were only told how powerful the magnetic field is during school. The instructors showed us pictures of the shopping carts and folding chairs that got sucked into the magnetic field, which destroyed the machines. Pretty cool stuff. Thanks for sharing.
I replied this in another comment: Well that has actually been tried. I work for a liquid helium supplier, we fill these systems. In order to capture the gas, you'd have to have several tube trailers to put it into, and another mechanical trailer for the large multi-stage compressor and it's plumbing... By time you get everything on site, hooked up, purged, then run it for several hours, you'd have lost a lot of money. The logistical details are terrible. Just better to let it go. And as it stands, this type of magnet here, has two separate vessels and both are tiny. We saw a loss of about 350 liters of liquid, tops.
@@2605155 thanks for this. I tried explaining that in the beginning, but the overwhelming number of ppl big mad about it was a bit overwhelming so I just stopped trying. lol
@@2605155 Two years later, is it not possible to first ramp down the magnet and then transfer the helium still in its liquid form to a already cold dewar (Or several depending on the volume of *liquid* helium inside the magnet) ? I heard that they don't quench old magnets anymore nowadays due to the price and scarcity of helium, recovering it instead.
@@psirvent8 Well yes, with time and money all things are possible. I would point out I don't think all systems are built internally to be able to do this. All the Siemens systems I work on have "bottom-fill" tubes that run down to the bottom and so do GE magnets. But I'm not sure how the weep holes in the fill tube of a Philips would allow pressurizing the vessel and a solid flow all the way up from the bottom... Somebody correct me if they can. I think cold dewars could accept liquid just as they deliver it, you can then walk right over to the new magnet coming in the door off the 18-wheeler and pump it over to it. Siemens does not keep the MRI (I call them magnets, jargon) as full as you think. Most are running with 300-400 liters and will never in their lives be filled up. Wouldn't be a lot to pump out. A GE with the LCC core does usually stay filled and certainly 85% or better for shimming. Plus, they're huge! I would think those were great candidates to provide helium to an inbound replacement unit. Anyway, I can't write a book here...
I find it to be like witchcraft in a way, you mean that current has been flowing in the superconductor for how many years? In that closed loop? this is insane.
Yup it is called a persistant switch. They charge it up with a loop of superconducting material above the transition temperature and when the desired amount of amps is reached it is allowed to cool. The quench button activates the same heater that turns off tge persistant loop and routes the magnet current through a small heating element. A rupture disk blows and bye bye helium...
It seems amazing that pressing such an accessible button releases all the coolant gases, and looks like it would cause some damage, in case of an accidental press! I really wish I could hear what the chap was saying though, because it was fascinating and I’m sure that what he was saying was interesting and educational. Also interesting seeing how powerful those magnets were, it really does drive home the reason why you have to remove your jewellery!
You wouldn't "damage" it from pressing the quench button accidentally. HOWEVER, it costs a LOT of money to re-pull the vacuum and then recharge the helium into the system, so you'd probably loose your job if you did that without good reason.
@@BlackEpyon You absolutely can damage the magnet by quenching it. The magnets are made of niobium-titanium alloy, and it's quite brittle (especially at low temperatures).
@@maddoggLP That's not steam, they're releasing the liquid helium out of the magnet and sending the boiled-off helium up the vent pipe - it's still so cold that it condenses water vapor out of the air when it exits the vent. A superconducting magnet only needs power to keep the helium liquid, as once a current is induced in the magnet coils (they're a closed loop) it continues as long as the magnet stays cold enough. And it takes a lot of current to make magnet that strong, so once the resistance comes back in the windings that current is high enough to cause hot spots and damage the windings. ua-cam.com/video/9SOUJP5dFEg/v-deo.html - the description on this video of another quench goes into much more detail, if you're interested.
@@SikerScrapyard It wasn't possible on site, at least we didn't have kit that could recover it, but our He suppliers did, at their plant. In our case, at Didcot in Oxfordshire. Their plant has what they called a bladder, which was made of, like mole skin or something! It was huge and all He gas bottles, or dewars (dewars are like highly efficient vacuum flasks, up to 500 Litres capacity. Come to think of it, they had one or two 1000 lt flasks as well.) They always had some helium left in them and this was all vented into the bladder, which was kept at a positive (He) pressure. I'm not sure if it was a continuous process or batch processed, but gaseous Helium was drawn off the bladder and compressed, then cooled, compressed again, cooled again and so on until, eventually it would become liquid again. Most of their Helium came from Algeria, so the reliquification plant only recovered a small percentage of their throughput. It was after my time, but everyone has clamped down on He wastage and it is much less than it was. New magnets are being developed that have far, far less liquid in them than the MRIs I worked on. They had about 2000 lt of liquid in them, but I believe the latest magnets have less than a tenth of that. The superconducting coil conductor is actually a copper tube with multifilaments of the actual (secret) conducting material inside it. The copper is the mechanical structure and the current dump in case it quenches. This has (apparently) been expanded slightly to circulate Helium through it, as well as carry the main superconducting current. Don't ask me, I retired five years ago!
A partial quench allows the temperature to rise and drop field strength, without losing that huge amount of helium. Recycle it would be better into a tanker. Thousands of £s of gas. When I was a student radiographer I was in the changing room nearby and somebody opened the main door and the bloody thing wiped all my cards and ID leaving in London miles from home with no money to eat or anything as those cash cards were all I had whilst away.
This is not just a quibble, folks. Helium is a finite resource, and once it is released into the atmosphere, we can't get it back. Unlike some industrial gases like argon or CO2, we cannot obtain He by distilling it from the atmosphere - it is a byproduct of certain specific natural gas wells. There are a lot of cool scientific and engineering tricks - used in everything from satellites to laboraties - which depend upon the properties of helium and which cannot be done without it. We will miss Helium when it is gone, in a big way.
@@railgap Oh please stop this bs about loosing the precious helium! It's just a byproduct of a natural gas industry and there is still SO much of it that some companies just vent it out when they pump and refine the natural gas because it is not worth it to separate and process the helium. It is so expensive not because it's rare but mostly because it's freakin difficult to clean and liquify. There also some helium rich gas deposits that still is not even started to be processed yet. Another fact is there just a huge margin schemes involved in the helium market situation when small number of companies monopolise the whole market and suppress all newcomers and all attempts to increase the production to keep so the prices high. -Oil shitfights in a nutshell:)
@@Zortorond Helium isn't produced by the same processes that make oil or natural gas. It's a byproduct of the nuclear decay or uranium and thorium, deep in the earth's crust. It just so happens to gather in gas pockets, which we can extract along with natural gas and oil. The PROBLEM that everybody's worrying about is that we're using that helium at a greater rate than we extract and refine it.
My dad said the best way to simulate one would be to stick your head inside an 55 gallon drum and have several people beat on it with hammers all at once.....
Not terrifying at all, to me! When I went in for an MRI, so many many MANY years ago... I just relaxed and pretended I was a large blood clot on the arterial wall of Newt Gingrich, and that the bangs and bumps resounding in the MRI machine were his beating heart. They were muffled through the ear protectors they had me wear, but I fantasized trying to decide whether I would separate and go into the heart, the lungs, or the brain. THUMP THUMP BANG THUD!! It was so much fun, picturing myself as a pulmonary embolism, and him on his knees, clutching at his chest... Yes, I would cut loose and hit the lungs. The heart was far too small, and the brains were nonexistent. I was loosening... loosening... soon I would break free and *kill* the sucker! Then the nurse pulled the platform out "Are you all right? You're smiling!" "Stupid woman! You ruined my Newt Gingrich Death Detachment Meditation!" And THAT, dear readers, is how you get a 24 hour psych hold! >:D
Years ago i won a portable one on ebay for about 14 grand. Put about 600 in ln2 in it and about 8 grand of helium in it, and got it up an running, ended up selling it for 120 grand to a hospital. Now a helium fill is gonna be about 30 grand or better 😲
Well that has actually been tried. I work for a liquid helium supplier, we fill these systems. In order to capture the gas, you'd have to have several tube trailers to put it into, and another mechanical trailer for the large multi-stage compressor and it's plumbing... By time you get everything on site, hooked up, purged, then run it for several hours, you'd have lost a lot of money. The logistical details are terrible. Just better to let it go. And as it stands, this type of magnet here, has two separate vessels and both are tiny. We saw a loss of about 350 liters of liquid, tops
@@2605155 I remember the story about a burst in the filling tube in a hospital, the entire hospital got inundated with helium. It made Apple iCrapple crash, it was funny. The iPhones were crashing because helium got inside the MEMs (Microelectromechanical systems), the MEMs were not only used to detect rotation, but also as a clock. They don't work when filled with helium.
Q: Is there an electrical power spike as the magnetic field collapses? (I'm thinking of how an ignition coil in an automobile works) Where did all of the electromagnetic energy that was supporting that HUGE magnetic field go?
Absolutely - an enormous spike which can destroy the windings. There is a much better way to turn off an SC Magnet that avoids this , AND recovers the Helium.
Yes boiling off the helium removes the super conductive capability of the windings. Being at near absolute zero makes the windings highly conductive enabling a strong magnetic field. Removing the heliem causes them to heat up causing the magnetic field to drop as the windings are no longer able to conduct electricity as well and resistance in the wires increase. So yes quenching can damage or destroy the windings. The process is usually done by an engineer from the company that built the machine. Quenching is the fastest way to decomision, but can be dangerous and costly, and done in life saving situations only. Dangerous as helium displaces the oxygen in the room and can cause asphyxiation if you remain in there and the helium concentration is too high. But in this case the machine is due to be decommissioned and probably replaced. Some hospitals don't like to do it thay way, others don't mind and like to do stuff like this to show how powerful the magnetic field, which is 30,000 times that of earths magnetic field, really is.
@@nebraskaninkansas347 Its cool physics. Absolute zero implies absolute zero resistance, the flyback effect is essentially thus stored in the magnet as a closed loop. Frozen in time, until superconductivity is lost. Then immediately comes your massive flyback response that can destroy the magnet windings. To think it was stored in the magnet for at least a decade.
@@nebraskaninkansas347 I heard that nowadays engineers don't quench the magnets anymore when decommissioning them due to the helium price and shortages. They ramp them down and more importantly recover the helium instead. But that might not necessarily be true everywhere in the world I guess ? 🤔
Why is this so dramatic, I could cry lol. It's just mind-blowing how this device never stops working from the seconds it's installed until it's retirement.
Damn 0.7 is relatively weak too. I've been in many MRIs, and i always have the urge to slam the quench button. I mean, its a giant red button and i don't really want another MRI.
@@tomhoehler3284 Yep. I've talked to MRI techs. That is the $10,000 button because that is about how much it will cost to get the system up and running again. Maybe more now, adjusted for inflation.
There are recovery systems. The problem is the cost of the system and the actual benefit it brings. Quenching isn't something that happens terribly often, most machines are only quenched at the end of their service. There are whole medical systems out there which have never had an emergency quenching. So, taking into account the cost of these systems, a cost which to my understanding increases greatly if being done as a retrofit, it simply doesn't makeup the cost in recovering that helium. Now, newer MRIs do have options with recovering helium gas off from normal operation, but that isn't the same as the kind of system needed to recover helium lost in such a high quantity.
@@cameronmalchow1837 : a large hospital system will have 100's of machines that will routinely need maintenance or get knocked offline for other reasons. Having a large scale machine and a 2 man crew would make plenty of economic sense especially if you a establish a regional service to recover helium for smaller hospitals that can't afford the CAPEX.
Because helium is such a lightweight gas it is lost forever when it is released into the atmosphere. It simply float up through the atmosphere and out into space where it will disperse so thinly that it wont be recoverable. Wasting helium like in this vidya is just plain thoughtless and stupid.
I work on MRIs once and awhile, most phones, it won't effect it. However if one quenches when they ramp up a MRI it can create an EMP and the phones with the wireless charging can be destroyed even down the hall.
@@flurgy22 That was specifically to do with phones (particularly iPhones) that use little MEMS chips for their CPU clock (essentially little microscopic metronomes), where the helium can seep in and stop it from functioning for several days or more.
I'm surprised there is not a way to recover that helium as it is a non renewable resource. An interesting thing about helium is that the molecules travel faster than the earth's escape velocity so it leaves the planet completely. Either way that was kind of cool to see. It would be tempting to go near that plume, would start to talk funny. :P
Yes - the helium molecules rise to the top of our atmosphere and escape. Next level: Jupiter is massive enough to capture and keep helium molecules swept outward by the solar wind. If you time it right, you could pop a party balloon and send a birthday wish to Jupiter.
Quite a waste, but helium used to be really cheap. Not so much now that the US surplus is running low. On the other side of the coin, noboy bothered mining helium for an entire century because the US surplus was so big and cheap (mined for airships that never got built). Now that there's financial incentive to do so, they've already looked for and found helium in several likely rock formations.
We're not "running out of helium" so much as we're using up the current stockpiles faster than we can extract and refine it. It's created naturally as a radioactive decay product from uranium and thorium in the earth's crust. It gathers in gas pockets, and is often extracted with oil and nautral gas as a byproduct, but "cleaning" it is a tedious process. You don't just stick a bottle onto a tap and pull it from the ground.
That’s in a way kinda sad. You are literally killing that machine. Once its quenched, the magnets will never come back online. But if you’re decommissioning the MRI machine, the magnets have to be quenched, like the machines last hurrah while it dies a gradual death
A controlled quench does not destroy the B-nought magnet. You just have to recool and then re-establish the field. What is irreversible is the loss of helium. Not attempting recovery of the helium is a shameful act of selfishness, it is a theft from future generations.
@@tetrabromobisphenol Sensationalist headline BS. WE ARE *NOT* running out of the second most common element in the universe. It was just cheaper to buy it from the US navy surplus - mined for airships they never built . Enough to supply the world for a century. Possibly the most colossal military over-purchasing in the history of humanity. Now that we're hitting the tail end of that surplus, they've already found helium in several likely formations. It'll just cost more now that the US isn't giving it away for a song.
@@skliros9235 experience. The chicken little headlines are 10-year-old headlines that keep repeating like chain emails. When you actually look, the situation has changed since.
Someone mentioned the huge flux density. Magnetic tape and credit cards are at risk. The flux must be stopped outside the room. On with the Faraday Cage!! I have decommissioned a couple hospital rooms, and a BUNCH of the mobile MRI semi-trailers. The entire room is is underlaid with aluminum sheets, (sometimes copper, expensive) or copper foil. Every seam is taped over with copper foil tape, also corners, conduit penetrations, vent screens. The door is the same way, and a type of flexible slotted gasket of copper foil or fine mesh in a roll, like window gasket, seals it when it is closed! To test the room for integrity, try to use a cell phone......no go if the room is correctly sealed!!
The cage has nothing to do with confining the magnetic field. It's there to stop RF radiation from escaping, and more importantly, to stop RF noise from entering, the magnet room.
@@NaughtyTasman Yeah, you got me on that one. I should have known better. I didn't think before composing that reply. The magnetic flux is contained by a thick steel plate shield box, in the case of an MRI without an integrated shield (usually the actual outer cylinder of the mag itself), or by the outer case of a steel-shrouded MRI. I have demolished both types. Many years ago, I decommissioned one in Swedish Covenent in Chicago. It had a 15-ton box around it. Luckily, it was made up of many many smaller blocks of steel. I didn't have to set up heavy burn equipment. I used a carbon-arc gouger to break all the welds and then port out the chunks with a hand cart. I cut up the MRI itself with a plasma cutter to keep the noise down (no air chisels or chop saws) which also kept the fire hazard down somewhat from all the Mylar sheeting inside. The center spool was fiberglass. The Faraday cage is indeed to contain all the RF. With the door shut, the cell phones wouldn't have any signal. The room was surrounded by aluminum plate Tig-welded everywhere. Any intrusion by cables or heating ducts, etc were taped over with copper foil tape, and the door of course had those "fingers" and metal screen gaskets.
@@junkdeal Very interesting. We don't need the huge steel boxes to contain the magnetic field anymore. We use bucking coils, which are essentially just extension coils at each end of the primary magnet coil, but wound the opposite way. The field inside the bore is very strong, but the bucking coils keep the field outside the bore within reasonably safe limits - the 200 gauss line is only a short distance along the cradle, even in 3.0 T systems.
@@NaughtyTasman I think I do remember these coils in a narrow slot on each end of the center spool, during demolition of later model mags. (I think this type of mag was called "active shield". They were stainless outer tanks, no thick steel.). I didn't know that this was their function though. You learn every day!!
There is a heater built in to the unit. Quench button activates the heater causing helium to expand from liquid state to gaseous state. Safety burst disc ruptures and helium rapidly vaporizes and vents up the quench pipe (chimney) to rooftop.
@@Fireship1 Well, almost but not quite... In fact those heaters heat up the main coil in several places then those parts of the coil loose superconductivity and obtain some electrical resistance and the current of about 500 amps do the rest of the heating all right;) And that is a lot of heat I tell you!:) So the rest goes just like you've said. That's why the field drops down so fast actually - all work is done way before the actual quench.
I have scrapped a lot of MRIs over the years, and that little heater grid inside the cold-tank looks like the inside grid of a milk-house heater or a bread toaster! I think the proximity to the coils does cause an instant loss of super-conductivity and that induced resistance probably helps! Interesting thing is, though, I have actually participated in more than one de-ramp, and within a mere MOMENT you can hear the "crinkling" noise of the burst disc just before it fails!! Then the fun begins!!! The one I removed from the hospital in Fond Du Lac Wisconsin (belonged to Mayo Clinic of Rochester MN) drew a HUGE crowd since they didn't warn anyone of the impending "storm"!!!!
I'm highly certain that's actually the air liquefying in contact with the extreme cold... to capture helium would not be too hard and they'd have to "vent" it into a tank through a compressor. Same way refrigerant recovery is done once air conditioners and condensing units from walk in coolers need to be retired.
It absolutely can be recovered. Look up Cryomech. The hospital system MBA dolts aren't able to think beyond 'medicare reimbursement' for ideas on how to save money so it never occurs to them to try He recovery.
They can get more. Nobody bothered mining helium for an entire century because the US had such a huge surplus for airships they never built and were giving it away for practically free. Now that there's economic reasons, there's already been helium found in several likely rock formations. It'll never be as cheap again, probably. We were profiting from the US' poor decisions.
@@tsm688 Helium isn't produced by the same processes that make oil or natural gas. It's a byproduct of the nuclear decay or uranium and thorium, deep in the earth's crust. It just so happens to gather in gas pockets, which we can extract along with natural gas and oil. The PROBLEM that everybody's worrying about is that we're using that helium at a greater rate than we extract and refine it.
@@tetrabromobisphenol It's cheaper to just let it go than to bring the tanker trucks and multi-stage compressors required to transfer the helium. Sure, you can do it, but it's not economical.
Imagine having a pacemaker or implant and forgetting to tell the doctors then all of a sudden the MRI grabs you and starts thrashing you around while hissing and shooting white smoke
Not to mention it's also an accuracy thing. Yes I can weld with a Powerkraft 180 welder from the 60's or a lincoln Powerwave from 2010(ish). Guess which one's more precise.
Go read the patents, there is a great deal of information on how they function. did you know the first one was invented in 1974? and they didn't get into hospitals until 1983.
I think that the Helium cannot be recovered because you need the latent heat capacity of the Helium to absorb the magnetic energy that is stored in the superconducting coils. If you simply removed the Helium then then coils would heat up and become normal conductors with resistance. Then the large circulating current would dissipate a huge amount of heat in the coil resistance. The coils would become white hot, melt and set fire to the builidng. But this does raise the question of what does quenching actually do? How does it cause the coil temperature to rise above the transition temperature while still allowing the Helium to absorb the energy?
I've often wondered how it works as well... someone else just said, there are He and LN in the cryo chamber. the LN must be there to keep the He from warming up, perhaps, if they vent the LN first, the field collapses very slowly, so you not get the HUGE Back EMF current spike... I'm not sure... interesting...
@@tekvax01 I'm thinking that perhaps they have a big resistor, ie. a heating element, which is also submerged in the Helium and is connected in series with the superconducting coil but is normally shorted out by a switch. Then to quench they open the switch allowing the current to flow in the heater. The heater absorbs the inductive energy dissipating it as heat and the Helium then absorbs the heat as it boils off.
Someone suggested putting a damned weather balloon over the vent. You'd have a hard time heating it sufficiently it wouldn't freeze in crack, but in principle, I'm at a loss trying to find a reason that wouldn't work.
MR engineer here. We can just ramp down the magnet (remove all the current from the super conductive coil) and then the liquid helium can be reclaimed safely and at leisure. But it's not as easy as just quenching the magnet and throwing all the helium away 🤕
So what's the point of retiring an MRI machine if it still works? Or what was the supposed problem with it? And how is one that was vented prematurely get restarted?
Given that liquid helium is getting harder to find and more expensive why not recover it from the machine rather than venting it into the atmosphere? Surly there has to be equipment to do that.
@@gavincurtis I swear stores are putting "watered down" helium in balloons these days. The lift force they exhibit feels way less than they did 20 years ago.
*WE ARE NOT* running out of the second most common element in the universe. The *US stockpile* is running dry, yes - the stockpile so massive nobody bothered mining for helium for an entire century. Now that there's money to be made, mining companies have already found helium in several likely rock formations (ones like the US stockpile came from - it didn't come from the atmosphere or elfin magic).
I thought you had to spin down the current in the coil to work on one of those things.....Of course, i suppose dumping the coolant and letting it heat up above superconductivity works too. especially for a decommissioning....shame to see all that helium just get vented to atmo though.....
They actually ramp down the magnet and recover most of the helium nowadays instead of quenching old magnets indeed because of how costly and scarce helium is. But you can't remove the helium before the magnet coil has properly been ramped down first.
Did they get a new one or why they put it out of service? Did they have this open machines for such long time already? Here in Germany they only have a few new machines without that closed tunnel.
The machine was so old, and image quality so bad that referring doctors would specifically request we not scan their patients on it. It happened often enough that the powers that be felt it was time.
Because the market is always 20 years behind scientific reality. MBAs can only understand economics with a 12 month time horizon. The concept of making a killing 5-10 years down the road simply does not compute for them.
Volcanoes release many times this amount of He before and during eruption. It would be more efficient to develop technology to capture that helium first.
The video is old so I'm not sure anyone will ever read this, but here it goes : Radio Tech student here. In MRI lessons, we usually see the more classical "donut" style. I don't recall ever seeing such a machine, so how come is it shaped this way ? And is it also medical use or research purpose ? Like some 7T exists nowadays.
This is an Open bore MRI. Heavily used in the early 2000s for claustrophobic patients.It's limitations are in resolution and signal quality due to it's low magnet strength. In recent years they've made advances that have larger bore sizes without the compromise on quality that have allowed high quality images for our claustrophobic population. So, as in this case, these machines have been phased out.
I'm surprised the natural gas industry isn't back on a helium recovery plan, since all the stuff that comes from WWII era reserves collected in that manner are getting pricey.
@@kauske its more that its not as big of an issue as the media is letting it on to be. makes a great headline and spooks not so intelligent people, like yourself.
@@thepjup4507 The fact you result to argumentum ad hominem shows the only 'not so intelligent person' here is you. If you understood the uses of helium and how it's constantly wasted, plust the realistic limits, you might actually care. But I guess your reasoning is 'I'll be dead before it becomes an issue', right? Just pawn it off on your kids/grandkids like climate change, _right?_
@@thepjup4507 I wonder how many other things you think is 'just the news making a big deal of', I wonder what your sources are for it 'not being a big deal'.
@@matthill5658 You quoted me saying "not being a big deal". Here is the actual quote: "not as big of an issue as the media is letting it on to be". The term 'As big of' is used relatively to compare two different things. Commons sense would deduce, then, that I am not implying, nor did I say "not a big deal". As for the sources, here you go: physicstoday.scitation.org/do/10.1063/PT.6.2.20200605a/full/ www.gasworld.com/kornbluth-helium-shortage-to-ease-in-2020/2018205.article www.gasworld.com/helium-oversupply-leads-to-a-pricing-plateau/2020020.article cen.acs.org/articles/95/i30/helium-way.html www.researchgate.net/publication/329684204_On_the_opportunities_of_the_shift_of_helium_industry_world_center_to_eastern_Siberia_Russia I doubt you'll read even one of those, but you asked for sources and there they are. Since it seems you have difficulty picking up on implied information, let me be 100% clear and direct. Yes, helium is a finite and dwindling resources, and it being completely gone is a big deal. However, it is in no current danger of being depleted, especially for industries that use it. I do believe there should be more sustainable practice with all resources, not only helium, but the helium shortage is indeed being spectacularized by the media. So, where are your sources saying it's a proven immediate danger?
The liquid helium keeps the magnet cold enough to be a "super conductor" that is, the current can just circulate around. It's not perpetual motion as energy is still required to maintain the extreme cold, but it doesnt require continuous power. In fact you could cut all power for a time without losing the field, just like losing power for a hour or two but the food in your fridge doesnt spoil. It requires much less energy to keep it cool than it would to supply current continuously to a traditional electromagnet. What the quench button does is intentionally heat the magnet until it loses its superconducting properties. This causes the circulating current to suddenly encounter resistance, causing everything to dramatically heat up. The helium becomes a gas again, and pressure builds until the emergency pressure release device gives way. It takes a lot of work, a specialized technician and a big tank of liquid helium to energize an MRI magnet, and this process is expensive in itself. Not only that, but the thermal shock of quenching it in this way could damage parts, too. That's why a quench should only be initiated if there's not only an immediate danger to people, but a danger that can be reduced or eliminated by immediately shutting down the field. For example, a person getting pinned against the MRI by a metal object, or if fire and rescue people can rescue someone, or put out a fire, more quickly if the field is gone.
Your mission, Dan/Jim, should you choose/decide to accept it, ... As always, should you or any of your IM Force be caught or killed, the Secretary will disavow any knowledge of your actions. This tape/disc will self-destruct in five/ten seconds. Good luck, Dan/Jim.
helium is inside and vents out, but the tube is frozen bellow condensation point of said gases and so they transfer to liquid state and run down the tube outer surface.
@@matyasd007 the liquid helium is used to cryogenically freeze the MRI magnets. When it is vented it cools the out side of the vent down. The air which is nitrogen and oxygen then condenses on the vent as well as moisture in the air.
Long story short, we are not running out of the second most common element in the universe, this is an economic issue. Nobody bothered mining helium for an entire century because the US had a stupidly large surplus (for airships they never built). Now that there's money to be made, people have looked for and found helium in several likely rock formations (like where the US surplus came from - they didn't make it from elfin magic.)
they hit the button, and it opens a big valve, and vents all the helium and nitrogen from the cryo chamber, once the bore coils have warmed up, it is no longer superconducting and the magnetic field collapses.
Once the superconducting magnet is no longer "superconducting," meaning that it's warmed up above that threshold, all the current in the coils becomes like a giant heater, which flash boils the liquid helium and nitrogen. This has the potential to damage the coils, even when done properly, so it's only done when they absolutely need to.
Grade 11 student here. Not really sure what's going on here and cant really hypothesize, nothing in my mind linked MRI machines and helium. Is the helium some sort of refrigerant for the meaty electromagnetic coils? Never looked into MRI functioning principles, but would really love to know. Can anybody provide a basic explanation, maybe refer me to some websites? Thanks.
The magnet in an MRI is an electromagnet meaning it requires an electric charge to be a magnet. There are two ways of doing that, running an electric current thru the magnet during the time you want to use it, or charging the magnet once and keeping it super cold so the charge can remain in the magnet indefinitely. That's where the helium comes in, it's so cold that it keeps the magnet close to absolute zero. Remove the helium, remove the magnetic field. Check Wikipedia, it's actually a pretty good resource, especially for a layman.
@@jimbojones806 Killing power to the machine would do jack didly to the electromagnetic feild becaaause the coils are superconductors and require no additional power other than what they where initially charged with.. you pull the plug and the power will just keep circling in the coils keeping the field until the helium heats up allowing the superconductive coils to become resistive again and halting the current. all fine and dandy but that could take a few hours and in an emergency situation one does not have a few hours so, they speed this up by violently ejecting the liquid helium. not very elegant but ain't nobody got time for that.
@@hoofinmouthproductionsllc3470 oOf. I'm not exactly a layman, y'know. :) I meant basic as in "quantum physics student basic", not "average intelligence" basic. Thanks for the explanation, but could ya maybe step it up a notch or two? I already know all that, I want to know the advanced functioning principles and math and deep science and all that stuff, if you don't mind. :)
@@stephenwilson8150 hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/nmr.html#c1 actually the hyperphysics website is pretty good in general, helped me no end with getting through my degree.
It'd be nice if they'd recovered it, but *WE ARE NOT* running out of the second most common element in the universe. The *US stockpile* is running dry, yes - the stockpile so massive nobody bothered mining for helium for an entire century. Now that there's money to be made, mining companies have already found helium in several likely rock formations (ones like the US stockpile came from - it didn't come from the atmosphere or elfin magic).
Because the quench system is there for extreme emergencies like someone pinned to the magnet by a large metal object. In that case there has to be a quick and *reliable* way to kill the field in order to save a life. And nowadays the helium is often recovered when the magnet is being decommissioned, however at the time of the video quenching it was more common.
Absolutely ! Yes it was quite a waste. Nowadays the helium is often recovered when a magnet is being decommissioned instead of it being vented out like in many videos.
If you wonder how this actually takes place, here it is. The MRI is a Dewar's container, at as close to absolute vacuum as possible on earth. It is layered round and round inside the tank with Mylar silver sheeting, which is a supreme barrier to heat in the radiant spectrum, for even further insulation (radiant heat will absolutely pass through a vacuum, or the sun would never heat the earth!!!). Just the warmth of the outside of the MRI tank will "radiate" heat inward inside the tank and this too has to be stopped. The vacuum will stop "conductive" heat transfer. NOW if that vacuum is compromised in ANY way the 1000 liters of liquid HE will boil SO FAST you can not imagine how quickly that will occur!!! The heat in the room will go through that compromised tank like LIGHTNING and boil most of it off in SECONDS!! IN FACT if the tank did NOT have a burst disc, the whole tank would EXPLODE with the violence of an exploding BOILER or a BUNDLE of dynamite!!! NOW FOR THE FUN FACT!! When the guy pushes the red button, it turns on a heater element (like a room heater or bread toaster) deep inside the tank. That blast of heat will cause cause a furious boiling of the liquid HE and the tank pressure will rise ENORMOUSLY!!! The burst disc will fail from pressure and the helium will roar out of that big opening into a vent pipe and outside the building. Once outside, the cold helium gas will condense all the humidity in the air and cause a huge CLOUD of frozen water vapor, just like in the sky!!.....................The MRI (if it is not being replaced) is now going to have to go through a terribly expensive process to re-install a vacuum in the tank and then to re-introduce liquid HE back in- this is called ramping up....................But, if you took a power drill and drilled, say, a half-inch hole through the outside of a live and functional MRI tank, you would first hear a loud sucking noise as the vacuum was lost. Moments later the MRI would go "nuts" inside with the boiling helium and it would rupture the burst disc and discharge the same way it would if you quenched it, just a little slower before it vented, BUT NOT MUCH!!! That is HOW FAST the heat would get inside the tank once the vacuum is gone!!!!
@Paul Flusk Some MRIs do exactly that. The cold-head recirculates the HE to keep it in a liquid state. In ones like the older Oxford are dual-cryogenic, and use liquid N2 in a layer between the inner magnet tank and the outer shell and use the "sacrificial" refrigerant effect to help maintain the extreme cold needed to keep the HE liquid. The temp needed to do that is on the order of MINUS 450 degrees, near absolute zero, the temp in deep space. In mid 2008, I scrapped one of these and 2 smaller ones, and after expenses, I put 47,000 dollars in my pocket in 3 days work! One of the best hits I ever made in the scrap business!!
This was actually really interesting to read. I had no idea how MRI machines worked.
@@ZachAsaD Just weird science! Few people I know have the grasp I have of boiler principles, BLEVE effect, cryogenic facts, etc!
@@junkdeal But you write helium symbol incorrectly. It is He not HE.
@@tokenlau7519 You do 'got" me on that one!! The way I wrote it would more imply High Explosive round like a tank shell! I never noticed when I wrote it, unless I kept my hand on the shift key too long!!
There goes the equivalent of my student debt in Helium.
Helium that the world is running out of now.
wtf is a student debt?
@beepIL *this comment was made by the YUROP gang*
@@moncorp1 I was about to say that
Student debt? Oh you must be an american hahahahahah
So this is the button they push when a new pope has been chosen?
Damnit; I came here to make that joke.
I’m dead.... lol!!!!
i think im retarded cause i dont get it
@@Patrick-zr8tv When the college of cardinals chooses a new pope they release white smoke into the air by burning the cast ballots to signal to the world a new pope has been chosen.
If a vote is cast and none of the candidates receive 2/3rds of the votes then black smoke is released by burning the cast ballots with a substance that turns the smoke from white to black.
Then the cardinals debate and hold another vote.
Hope this clears it up for you.
@@MousePounder Ah thankyou, never knew that was a thing.
Never seen an MRI like that before, very cool to watch. Used to clean in a couple hospitals, and dusting/cleaning around these was always a fun way to spook coworkers and even getting spooked myself a few times. I was working 3rd shift, the area was shut down and not in use at night in the children's hospital. I was in the room by myself mopping. As I mopped closer to the MRI, I felt something tugging the back of my bra and then the underwires. I spin around about to chew someone out for creeping on up on and realize the MRI was just being pervy.
Im a guy, but i take you as a superhero.
I couldn't bear a single minute alone, at night inside a hospital
Mosty because my undermind is filled with creepy stuff
But at least you made me laugh when you said that MRI was being pervy on you
@@professional6513 Lol, glad I could make you smile! Most of the hospital was still well lit even at night (if you get admitted, bring an eye mask). I only had a couple of spooky/creepy moments while I worked there. The one area was the recovery for children after surgery; that gets shut down completely at night. Heard a baby crying in one of the recovery rooms at 3AM. The other was in an area that had light patient traffic. Was cleaning in adult radiology, one of the PET scan rooms and something just felt off, like the hairs raising up on the back of your neck. Never saw anything, but speaking to a radiologist later during a break, they told me of the resident ghost in that area that likes to knock clocks off the walls. Gross job, but it was really fascinating.
@@an0ana ooooohh..... hospital ghost stories.... Please continue.....
@@tekvax01 I was working late by myself at my desk in the Clinical Engineering Lab of a very large hospital. I looked up from my desk and saw a young boy who looked just fine standing in the doorway to the Lab. I asked him if he was lost and he smiled and shook his head. I then asked if I could walk him back to find his parents somewhere, again without a word he just kept smiling and shook his head. I said, "Ok, well have a nice night" he smiled and turned around and walked out of the door. About five seconds later, I decided that I would help him anyway, that he must be lost. Our Lab was at least 100 yards from any patient care facilities down a long door-less corridor. When I got to the door and looked down the hall he was nowhere in sight. I ran as fast as I could down the hall to try to catch him but never saw him again. There is no way a young boy could have made that distance in the 5 seconds it took me to get to the door. I knew then that it as something else. I always thought I would be scared poopless if i saw a ghost. However it was actually a calming and very pleasant experience.
@@quicksc1 Wow! I've never seen one or had an experience before, but I know several people that have...
Some have been harmless like yours, whilst others, downright scary... If I ever do, I hope mine is the former and not the latter... .
"I don't want to get too close with my phone, it might erase it". If you're in the room with your phone, you are already too close!
^ This! ^ -- MRIs are to magnetic fields as Tesla coils are to electric fields. However, the gradient must also be considered, and the gradient - not just the absolute field intensity - is "worst" closest to the magnet.
Even so, I have "non-magnetic" piercings... and I treasure my phone and can't afford to buy new ones casually so... yeah, i wouldn't get within ten feet of the door to the magnet room without stripping _completely_ naked, _sans_ornement_.
I've accidentally taken my phone into 7.05 Tesla magnetic fields before. If I got too close it would turn off. However, it had no effect at about 5 feet away where the field strength was indicated to be 5 Telsa. Considering this MRI only has a 0.7 T magnet, if you are even 3 feet away your phone should not have any issues. When people start out working around strong magnets they get paranoid about metal, but as it turns out most metal on us (keys, rings, etc) are diamagnetic.
Yeah there is a difference if our phones had hard drives then every time you would drop your phone it would mess up the hard drive more and more eventually rendering the information on the hard drive useless and deleted, same happens if you bang around your laptop if it has a hard drive
@The Mini Machinist Some solid state devices are affected. An acquaintance of mine works in a medical field and his hearing aids were destroyed when he went into an MRI room to assist with patient care. I don't know if the machine was actively scanning. The RF energy injected into the magnetic field can mess with electronic circuitry, not just magnetic storage media.
And then he found out that it was actually the one in room 205 that was being decommissioned...
Shel silverstein wrote a poem about a demolition company that went to the wrong address. Thanks for reminding me of that.
Reminds me of those people who unloaded like 1000 bricks at the wrong address.
It's okay. It's just a shitload of helium. I mean, it's an irrecoverable, scarce, and non-renewable resource, but it wouldn't be that hard to replace.
@@JohnnyWishbone85 you are aware of the helium depletion we are starting to face, yes?
@@FlashDrive356 Can you fucking read?
And just like that, a small fortune in helium went up the stack.
Knowing that we're running out of helium, it annoys me that they didn't try to at least capture it
What is it quenched with? I've never seen this done before so my curiosity is high now.
@@tlw2585 Quenching refers to the sudden loss of liquid helium from a superconducting electromagnet. The loss of liquid helium raises the temperature of the electromagnet's field coils above that which they are no longer superconducting. The increased resistance generates heat which quickly boils off the liquid helium along with the liquid nitrogen surrounding it. A quench event may result in irreparable damage to the electromagnet.
@@MrHack4never were not really "running out" of helium like you would think we are. We still have plenty to fill all the party balloons you want to lol.
One m.r.i. can contain 10,000 lieters of liquid helium, aka 7.5 million liters of helium gas, about 17,500,000 party balloons if i did my math right. Per quench. This is a upper limit but it shows just how much it wastes. On the other hand there is no feasible way to recover it, as it is extremely difficult to transport. However at around $35,000 of just the cost of liquid in the us and outside up to $150,000 is worth a fair amount. I would personally find a way to recover it, even if it cost 10k per, if i make 30k it would be worth a lot of setup. That said it boils at 6 kelven and air liquifies at 84 kelvin. It takes a lot of specialized equipment to store let alone recover. One of the reasons it is so exspencive.
Believe it or not, the circuit that does this is literally just a 9v battery with a little coil that heats up. That little bit is enough to push the liquid helium well past the point of blowing the vent cap. Pretty cool.
That's incredible.
I thought it was a little more powerful heater that was powered from the mains.
Fascinating that it's not just a venting solenoid or switch that opens a valve to atmosphere. Vacuum envelope or not, you vent that helium to atmosphere as a liquid it's gone either way.
@@RobertMorgan I think breaking the vacuum would make the helium vaporize and expand so violently that the not so large quench vent wouldn't let enough of it out fast enough and the whole magnet would end up exploding like if the quench vent wasn't even there.
Look up for Travis Sylvester MRI explosion in the serach bar of this website and you'll find a video where they do eaxctly that: Pulling the cap off the vacuum jacket (Using quite a long rope to be safe 😂😂) and then BOOM !
@@psirvent8 You better believe you're right!! I have pulled those plugs out of the "hole" they are in. Vacuum really is all that is holding this plug in. A good yank will remove it! You should hear the screech of the air rushing into that hole! If there was a lot of liquid helium still inside, it could and probably would blow up the tank! An old dual-cryo unit like an early Siemens with bolted end domes would be a REALLY good candidate for a blast! The welded ones would fail at the inner seam of the bore tube to end plate weld! One time I had a liquid oxygen Dewar in my truck and knocked the liquid level gauge off under a motel canopy, and the roar of the expanding oxygen caused the people in the office to rush out in panic and call 911!!! And that wasn't even a compromised vacuum situation! Just the hot air near the top of where it broke off was enough for the liquid to go nuts!!
@@junkdealActually I might have been a lil' bit wrong, as I did ask Travis Sylvester about the explosion and he actually told me that the quench vent had been capped before the video, for the sole purpose of blowing the vessel up just for fun.
He also said that a properly working quench vent should be able to prevent an explosion even if the vacuum plug were to be taken off.
Still the emergency button doesn't affect the vacuum but activates small heater deep within the superconducting windings to make them heat up and vaporize the helium.
That was strangely sad
It could be restarted, but would need a liquid helium recharge.
That machine finally finished its job.
It was sad to see such a grand thing be killed
@@norbertfleck812 what's wrong with it? Too outdated?
@@RNCHFND Yes. Newer MRT have got a much better resolution.
I like to imagine this is just two angry interns and the hospital was *pissed*
I feel sorry for the pigeons that were nesting in the vent stack. They're solidly frozen now.
As they should be.
Snac
@@maecinen9926 no
good, we dont need those infested flying rats
Yeah!!!! Some years ago I bought a junker fuel tanker that hadn't been started in a couple years, and when I stepped on the pedal, it was raining straw and baby birds out of the shotgun stack!!!
Thanks for recording this. You passed up a great opportunity to describe what was happening, though.
This! X100,000,000,000
Inside a MRI machine is a superconducting magnet with some hefty current circulating in it. It creates a very strong magnetic field needed for the imaging. The more the merrier, but also more dangerous. The magnet is cooled by liquid helium (4 K −269 °C −450 °F).
The emergency quench button disrupts the current, causing the magnetic field to disappear, but this also resleases the substantial amount of energy stored in the current, which dissipates as heat boiling off the liquid helium.
A quench is also a failure mode in superconducting magnet where the conductor loses its superconductor property, the current in a coil suddenly sees a resistance and a voltage spike occurs due to induction law. Again the stored energy gets dissipated by heating stuff and boiling off the helium.
@@sashimanu thanks
@@sashimanu thank you, sir, they doubtfully would have been able to explain it like that, anyway. Good job.
@@sashimanu See also what happened at CERN. Brian Cox did a video about it. Brilliant explanation.
Thats one expensive fog machine right there.
For anyone wondering what's happening, here is the basic rundown. The magnet is so powerful because it's cooled by extremely cold helium. When the EMERGENCY button is pushed the really cold helium is released and magnet stops.
Actually pushing the button heats up the coil, causing the helium to boil and vent as gas.
An important point: It's a massive electromagnet, cooled to superconducting temperatures. This means than once the magnet is powered, it's unstoppable until that cooling is removed and it heats back up. There is no turning an MRI magnet on or off, once it's electromagentized as a superconductor, it has zero resistance.
I'm a retired BMET and never got the opportunity to install or de-install an MRI. We were only told how powerful the magnetic field is during school. The instructors showed us pictures of the shopping carts and folding chairs that got sucked into the magnetic field, which destroyed the machines. Pretty cool stuff. Thanks for sharing.
(spoken in a high pitched voice) "Waste of expensive helium!"
I replied this in another comment: Well that has actually been tried. I work for a liquid helium supplier, we fill these systems. In order to capture the gas, you'd have to have several tube trailers to put it into, and another mechanical trailer for the large multi-stage compressor and it's plumbing... By time you get everything on site, hooked up, purged, then run it for several hours, you'd have lost a lot of money. The logistical details are terrible. Just better to let it go. And as it stands, this type of magnet here, has two separate vessels and both are tiny. We saw a loss of about 350 liters of liquid, tops.
@@2605155 As my Dad would have said: "If there was profit in it, someone would do it."
@@2605155 thanks for this. I tried explaining that in the beginning, but the overwhelming number of ppl big mad about it was a bit overwhelming so I just stopped trying. lol
@@2605155 Two years later, is it not possible to first ramp down the magnet and then transfer the helium still in its liquid form to a already cold dewar (Or several depending on the volume of *liquid* helium inside the magnet) ?
I heard that they don't quench old magnets anymore nowadays due to the price and scarcity of helium, recovering it instead.
@@psirvent8 Well yes, with time and money all things are possible. I would point out I don't think all systems are built internally to be able to do this. All the Siemens systems I work on have "bottom-fill" tubes that run down to the bottom and so do GE magnets. But I'm not sure how the weep holes in the fill tube of a Philips would allow pressurizing the vessel and a solid flow all the way up from the bottom... Somebody correct me if they can.
I think cold dewars could accept liquid just as they deliver it, you can then walk right over to the new magnet coming in the door off the 18-wheeler and pump it over to it.
Siemens does not keep the MRI (I call them magnets, jargon) as full as you think. Most are running with 300-400 liters and will never in their lives be filled up. Wouldn't be a lot to pump out.
A GE with the LCC core does usually stay filled and certainly 85% or better for shimming. Plus, they're huge! I would think those were great candidates to provide helium to an inbound replacement unit. Anyway, I can't write a book here...
I find it to be like witchcraft in a way, you mean that current has been flowing in the superconductor for how many years? In that closed loop? this is insane.
Yup it is called a persistant switch. They charge it up with a loop of superconducting material above the transition temperature and when the desired amount of amps is reached it is allowed to cool. The quench button activates the same heater that turns off tge persistant loop and routes the magnet current through a small heating element. A rupture disk blows and bye bye helium...
It seems amazing that pressing such an accessible button releases all the coolant gases, and looks like it would cause some damage, in case of an accidental press! I really wish I could hear what the chap was saying though, because it was fascinating and I’m sure that what he was saying was interesting and educational.
Also interesting seeing how powerful those magnets were, it really does drive home the reason why you have to remove your jewellery!
You wouldn't "damage" it from pressing the quench button accidentally. HOWEVER, it costs a LOT of money to re-pull the vacuum and then recharge the helium into the system, so you'd probably loose your job if you did that without good reason.
@@BlackEpyon You absolutely can damage the magnet by quenching it. The magnets are made of niobium-titanium alloy, and it's quite brittle (especially at low temperatures).
@@AlexBesogonov Makes sense.
Farewell faithful MRI magnet :'(
That was an old one
F's in chat for Ferromagnetic
Thank you, great display of a seemingly very well maintained MRI being quenched.
Quite genuinely, I've been there, done that. MRI engineer for about 23 years and a CT engineer since 1977. I miss it, but I enjoy retirement more.
So can you explain why this steam is needed? And why is that all irreversible? Why don’t just cut the power off?
@@maddoggLP That's not steam, they're releasing the liquid helium out of the magnet and sending the boiled-off helium up the vent pipe - it's still so cold that it condenses water vapor out of the air when it exits the vent. A superconducting magnet only needs power to keep the helium liquid, as once a current is induced in the magnet coils (they're a closed loop) it continues as long as the magnet stays cold enough. And it takes a lot of current to make magnet that strong, so once the resistance comes back in the windings that current is high enough to cause hot spots and damage the windings.
ua-cam.com/video/9SOUJP5dFEg/v-deo.html - the description on this video of another quench goes into much more detail, if you're interested.
@@SikerScrapyard It wasn't possible on site, at least we didn't have kit that could recover it, but our He suppliers did, at their plant. In our case, at Didcot in Oxfordshire. Their plant has what they called a bladder, which was made of, like mole skin or something! It was huge and all He gas bottles, or dewars (dewars are like highly efficient vacuum flasks, up to 500 Litres capacity. Come to think of it, they had one or two 1000 lt flasks as well.) They always had some helium left in them and this was all vented into the bladder, which was kept at a positive (He) pressure.
I'm not sure if it was a continuous process or batch processed, but gaseous Helium was drawn off the bladder and compressed, then cooled, compressed again, cooled again and so on until, eventually it would become liquid again. Most of their Helium came from Algeria, so the reliquification plant only recovered a small percentage of their throughput.
It was after my time, but everyone has clamped down on He wastage and it is much less than it was. New magnets are being developed that have far, far less liquid in them than the MRIs I worked on. They had about 2000 lt of liquid in them, but I believe the latest magnets have less than a tenth of that. The superconducting coil conductor is actually a copper tube with multifilaments of the actual (secret) conducting material inside it. The copper is the mechanical structure and the current dump in case it quenches. This has (apparently) been expanded slightly to circulate Helium through it, as well as carry the main superconducting current. Don't ask me, I retired five years ago!
Greatest video All Time of an MRI Quench ! RIP Hitachi 3/2018
A partial quench allows the temperature to rise and drop field strength, without losing that huge amount of helium. Recycle it would be better into a tanker. Thousands of £s of gas.
When I was a student radiographer I was in the changing room nearby and somebody opened the main door and the bloody thing wiped all my cards and ID leaving in London miles from home with no money to eat or anything as those cash cards were all I had whilst away.
This is not just a quibble, folks. Helium is a finite resource, and once it is released into the atmosphere, we can't get it back. Unlike some industrial gases like argon or CO2, we cannot obtain He by distilling it from the atmosphere - it is a byproduct of certain specific natural gas wells. There are a lot of cool scientific and engineering tricks - used in everything from satellites to laboraties - which depend upon the properties of helium and which cannot be done without it. We will miss Helium when it is gone, in a big way.
@@railgap Start mining all the Helium-3 from the moon...
@@BigDish101 of course, make sure the clones don't meet their replacement...
@@railgap Oh please stop this bs about loosing the precious helium! It's just a byproduct of a natural gas industry and there is still SO much of it that some companies just vent it out when they pump and refine the natural gas because it is not worth it to separate and process the helium. It is so expensive not because it's rare but mostly because it's freakin difficult to clean and liquify. There also some helium rich gas deposits that still is not even started to be processed yet. Another fact is there just a huge margin schemes involved in the helium market situation when small number of companies monopolise the whole market and suppress all newcomers and all attempts to increase the production to keep so the prices high. -Oil shitfights in a nutshell:)
@@Zortorond Helium isn't produced by the same processes that make oil or natural gas. It's a byproduct of the nuclear decay or uranium and thorium, deep in the earth's crust. It just so happens to gather in gas pockets, which we can extract along with natural gas and oil. The PROBLEM that everybody's worrying about is that we're using that helium at a greater rate than we extract and refine it.
"I pressed the AZ5 button!"
Apparently there are up to 1000L of liquid Helium in a MRI, with up to $15dollars PER LITER that is indeed a pricy death.
And a waste because helium is a finite amount on earth
@@marknielsen9315 Well if you filled it with just about anything else it would be too heavy
@@marknielsen9315 we will have to start tapping the sun for some more
@@nemo-x i think it mainly to do with safety, if a fire ever happens or a hydrogen leak encounters a spark you'll have yourself a bomb
@@nemo-x I wonder why we don't use hydrogen?
A black and white film starts playing.
You can't salvage the helium?!?!?
This makes me think one or more MBA's was involved in the design process.
Probably taught as example project in Business School.
What a waste of helium!
Not in a quench. Most recycle normal boil off. The quench vent is only for emergency use.
the sounds of a mri is terrifying
There just so THICK
My dad said the best way to simulate one would be to stick your head inside an 55 gallon drum and have several people beat on it with hammers all at once.....
Finest industrial techno
they are loud aren't they... 120 to 130 dB SPL at times, depending on the type of scans.
Not terrifying at all, to me! When I went in for an MRI, so many many MANY years ago... I just relaxed and pretended I was a large blood clot on the arterial wall of Newt Gingrich, and that the bangs and bumps resounding in the MRI machine were his beating heart. They were muffled through the ear protectors they had me wear, but I fantasized trying to decide whether I would separate and go into the heart, the lungs, or the brain. THUMP THUMP BANG THUD!!
It was so much fun, picturing myself as a pulmonary embolism, and him on his knees, clutching at his chest... Yes, I would cut loose and hit the lungs. The heart was far too small, and the brains were nonexistent. I was loosening... loosening... soon I would break free and *kill* the sucker!
Then the nurse pulled the platform out "Are you all right? You're smiling!" "Stupid woman! You ruined my Newt Gingrich Death Detachment Meditation!"
And THAT, dear readers, is how you get a 24 hour psych hold! >:D
I'm a banker and I've financed these machines. They run from $2million to upwards of $8 million.
Wow! They make all that money back in just about 2 uses!
Years ago i won a portable one on ebay for about 14 grand. Put about 600 in ln2 in it and about 8 grand of helium in it, and got it up an running, ended up selling it for 120 grand to a hospital. Now a helium fill is gonna be about 30 grand or better 😲
Overpriced.
Pretty sure the dripping is liquid oxegen or nitrogen. The helium is so cold it can liquefy air
It is liquid air indeed.
The whole town sounded like Donald Duck for a week with all that helium vented hehe.
So Helium is getting more and more expensive but you just vent it to atmosphere instead of recovering it?
I like to think of it as setting it free.
I mean... Most mri do eat through the stuff and need refilling once every few months or less, i guess it's just not worth the retrofitting
Well that has actually been tried. I work for a liquid helium supplier, we fill these systems. In order to capture the gas, you'd have to have several tube trailers to put it into, and another mechanical trailer for the large multi-stage compressor and it's plumbing... By time you get everything on site, hooked up, purged, then run it for several hours, you'd have lost a lot of money. The logistical details are terrible. Just better to let it go. And as it stands, this type of magnet here, has two separate vessels and both are tiny. We saw a loss of about 350 liters of liquid, tops
@@2605155 I remember the story about a burst in the filling tube in a hospital, the entire hospital got inundated with helium. It made Apple iCrapple crash, it was funny.
The iPhones were crashing because helium got inside the MEMs (Microelectromechanical systems), the MEMs were not only used to detect rotation, but also as a clock. They don't work when filled with helium.
That employee was paid tp pass gas. The machine was irritated---it had to vent. The situation is up in the air.
Underrated comment right here.
That machine had issues man geez
This is probably one of the most well thought out comments I've read in a whole year. Thank you for the laughs my friend.
The new phones with the cordless chargers, they get killed easily by a quenching magnet.
@@mrow7598 oh, how's that? Wireless chargers?
Q: Is there an electrical power spike as the magnetic field collapses? (I'm thinking of how an ignition coil in an automobile works) Where did all of the electromagnetic energy that was supporting that HUGE magnetic field go?
Absolutely - an enormous spike which can destroy the windings. There is a much better way to turn off an SC Magnet that avoids this , AND recovers the Helium.
Yes boiling off the helium removes the super conductive capability of the windings. Being at near absolute zero makes the windings highly conductive enabling a strong magnetic field. Removing the heliem causes them to heat up causing the magnetic field to drop as the windings are no longer able to conduct electricity as well and resistance in the wires increase. So yes quenching can damage or destroy the windings. The process is usually done by an engineer from the company that built the machine. Quenching is the fastest way to decomision, but can be dangerous and costly, and done in life saving situations only. Dangerous as helium displaces the oxygen in the room and can cause asphyxiation if you remain in there and the helium concentration is too high. But in this case the machine is due to be decommissioned and probably replaced. Some hospitals don't like to do it thay way, others don't mind and like to do stuff like this to show how powerful the magnetic field, which is 30,000 times that of earths magnetic field, really is.
@@nebraskaninkansas347 Its cool physics. Absolute zero implies absolute zero resistance, the flyback effect is essentially thus stored in the magnet as a closed loop. Frozen in time, until superconductivity is lost. Then immediately comes your massive flyback response that can destroy the magnet windings. To think it was stored in the magnet for at least a decade.
@@clivebradley2633 the energy is released in the coils as heat, boiling more He and causing the magnetic field to collapse and turn into heat.
@@nebraskaninkansas347 I heard that nowadays engineers don't quench the magnets anymore when decommissioning them due to the helium price and shortages. They ramp them down and more importantly recover the helium instead.
But that might not necessarily be true everywhere in the world I guess ? 🤔
20 years as a DI director and I never had the opportunity to witness a quench.
Is it because they were recovering liquid helium out of old magnets instead of quenching them ?
I should say you’re lucky. 😂
Got here because of Vsauce Michael
ImNvrRdy same 😂
Cool. Did he mention this video specifically? Which episode so i can check it out?
@@hoofinmouthproductionsllc3470 Not this video specifically but he mentioned MRI quenching and I got curious.
Same, haha
@@hoofinmouthproductionsllc3470 Lenz's Law on D!ng. It's a treat :)
Why is this so dramatic, I could cry lol.
It's just mind-blowing how this device never stops working from the seconds it's installed until it's retirement.
The $60,000 oops button.
"The closest I'll come to pushing a quench button..." ... is exactly right on, since you pushed it!
Damn 0.7 is relatively weak too. I've been in many MRIs, and i always have the urge to slam the quench button. I mean, its a giant red button and i don't really want another MRI.
It would be a costly urge. You would regret it. Why don't you like MRI's? I've had several, not so bad....
@@tomhoehler3284 Yep. I've talked to MRI techs. That is the $10,000 button because that is about how much it will cost to get the system up and running again. Maybe more now, adjusted for inflation.
@@wesleyhurd3574 it was closer to 100k last time that happened in my system that I'm aware of.
I spent 2hrs 15min in one once.
@@wesleyhurd3574 150,000
"DR Williams, the patient is still waiting for that scan"
"...oh shit"
Doesn't a way exist to recapture the helium? It seems like such a waste to release it into the atmosphere.
There are recovery systems. The problem is the cost of the system and the actual benefit it brings. Quenching isn't something that happens terribly often, most machines are only quenched at the end of their service. There are whole medical systems out there which have never had an emergency quenching. So, taking into account the cost of these systems, a cost which to my understanding increases greatly if being done as a retrofit, it simply doesn't makeup the cost in recovering that helium. Now, newer MRIs do have options with recovering helium gas off from normal operation, but that isn't the same as the kind of system needed to recover helium lost in such a high quantity.
It is - see my comment above.
@@cameronmalchow1837 : a large hospital system will have 100's of machines that will routinely need maintenance or get knocked offline for other reasons. Having a large scale machine and a 2 man crew would make plenty of economic sense especially if you a establish a regional service to recover helium for smaller hospitals that can't afford the CAPEX.
Because helium is such a lightweight gas it is lost forever when it is released into the atmosphere. It simply float up through the atmosphere and out into space where it will disperse so thinly that it wont be recoverable.
Wasting helium like in this vidya is just plain thoughtless and stupid.
@@tetrabromobisphenol are you saying there is a mobile recapture solution?
And then everybody's iPhone stopped working.
I work on MRIs once and awhile, most phones, it won't effect it. However if one quenches when they ramp up a MRI it can create an EMP and the phones with the wireless charging can be destroyed even down the hall.
@@mrow7598 this comment was a while back but I think I was referring to the helium getting into the phone and causing it to temporarily stop working.
@@flurgy22 That was specifically to do with phones (particularly iPhones) that use little MEMS chips for their CPU clock (essentially little microscopic metronomes), where the helium can seep in and stop it from functioning for several days or more.
Props for a majorly obscure youtube reference.
@@andybaldman ua-cam.com/video/vvzWaVvB908/v-deo.html
I'm surprised there is not a way to recover that helium as it is a non renewable resource. An interesting thing about helium is that the molecules travel faster than the earth's escape velocity so it leaves the planet completely. Either way that was kind of cool to see. It would be tempting to go near that plume, would start to talk funny. :P
Most of that plume was the surrounding liquid nitrogen from the cooling jacket vaporizing.
Yes - the helium molecules rise to the top of our atmosphere and escape. Next level: Jupiter is massive enough to capture and keep helium molecules swept outward by the solar wind. If you time it right, you could pop a party balloon and send a birthday wish to Jupiter.
Quite a waste, but helium used to be really cheap. Not so much now that the US surplus is running low.
On the other side of the coin, noboy bothered mining helium for an entire century because the US surplus was so big and cheap (mined for airships that never got built). Now that there's financial incentive to do so, they've already looked for and found helium in several likely rock formations.
We're not "running out of helium" so much as we're using up the current stockpiles faster than we can extract and refine it. It's created naturally as a radioactive decay product from uranium and thorium in the earth's crust. It gathers in gas pockets, and is often extracted with oil and nautral gas as a byproduct, but "cleaning" it is a tedious process. You don't just stick a bottle onto a tap and pull it from the ground.
There is a way, but it is more time consuming. In this case they may have chosen a quench to replace the maching quicker.
That’s in a way kinda sad. You are literally killing that machine. Once its quenched, the magnets will never come back online. But if you’re decommissioning the MRI machine, the magnets have to be quenched, like the machines last hurrah while it dies a gradual death
‘I’ll be back’
A controlled quench does not destroy the B-nought magnet. You just have to recool and then re-establish the field. What is irreversible is the loss of helium. Not attempting recovery of the helium is a shameful act of selfishness, it is a theft from future generations.
@@tetrabromobisphenol Sensationalist headline BS. WE ARE *NOT* running out of the second most common element in the universe. It was just cheaper to buy it from the US navy surplus - mined for airships they never built . Enough to supply the world for a century. Possibly the most colossal military over-purchasing in the history of humanity.
Now that we're hitting the tail end of that surplus, they've already found helium in several likely formations. It'll just cost more now that the US isn't giving it away for a song.
@@tsm688 how do you know all that? Lol
@@skliros9235 experience. The chicken little headlines are 10-year-old headlines that keep repeating like chain emails. When you actually look, the situation has changed since.
Someone mentioned the huge flux density. Magnetic tape and credit cards are at risk. The flux must be stopped outside the room. On with the Faraday Cage!! I have decommissioned a couple hospital rooms, and a BUNCH of the mobile MRI semi-trailers. The entire room is is underlaid with aluminum sheets, (sometimes copper, expensive) or copper foil. Every seam is taped over with copper foil tape, also corners, conduit penetrations, vent screens. The door is the same way, and a type of flexible slotted gasket of copper foil or fine mesh in a roll, like window gasket, seals it when it is closed! To test the room for integrity, try to use a cell phone......no go if the room is correctly sealed!!
The cage has nothing to do with confining the magnetic field. It's there to stop RF radiation from escaping, and more importantly, to stop RF noise from entering, the magnet room.
☝
@@NaughtyTasman Yeah, you got me on that one. I should have known better. I didn't think before composing that reply. The magnetic flux is contained by a thick steel plate shield box, in the case of an MRI without an integrated shield (usually the actual outer cylinder of the mag itself), or by the outer case of a steel-shrouded MRI. I have demolished both types. Many years ago, I decommissioned one in Swedish Covenent in Chicago. It had a 15-ton box around it. Luckily, it was made up of many many smaller blocks of steel. I didn't have to set up heavy burn equipment. I used a carbon-arc gouger to break all the welds and then port out the chunks with a hand cart. I cut up the MRI itself with a plasma cutter to keep the noise down (no air chisels or chop saws) which also kept the fire hazard down somewhat from all the Mylar sheeting inside. The center spool was fiberglass.
The Faraday cage is indeed to contain all the RF. With the door shut, the cell phones wouldn't have any signal. The room was surrounded by aluminum plate Tig-welded everywhere. Any intrusion by cables or heating ducts, etc were taped over with copper foil tape, and the door of course had those "fingers" and metal screen gaskets.
@@junkdeal Very interesting. We don't need the huge steel boxes to contain the magnetic field anymore. We use bucking coils, which are essentially just extension coils at each end of the primary magnet coil, but wound the opposite way. The field inside the bore is very strong, but the bucking coils keep the field outside the bore within reasonably safe limits - the 200 gauss line is only a short distance along the cradle, even in 3.0 T systems.
@@NaughtyTasman I think I do remember these coils in a narrow slot on each end of the center spool, during demolition of later model mags. (I think this type of mag was called "active shield". They were stainless outer tanks, no thick steel.). I didn't know that this was their function though.
You learn every day!!
movie scallet bullet..
I would like to know more about how emergency stop button/ quenching works.
There is a heater built in to the unit. Quench button activates the heater causing helium to expand from liquid state to gaseous state. Safety burst disc ruptures and helium rapidly vaporizes and vents up the quench pipe (chimney) to rooftop.
@@Fireship1 Well, almost but not quite... In fact those heaters heat up the main coil in several places then those parts of the coil loose superconductivity and obtain some electrical resistance and the current of about 500 amps do the rest of the heating all right;) And that is a lot of heat I tell you!:) So the rest goes just like you've said.
That's why the field drops down so fast actually - all work is done way before the actual quench.
I have scrapped a lot of MRIs over the years, and that little heater grid inside the cold-tank looks like the inside grid of a milk-house heater or a bread toaster! I think the proximity to the coils does cause an instant loss of super-conductivity and that induced resistance probably helps! Interesting thing is, though, I have actually participated in more than one de-ramp, and within a mere MOMENT you can hear the "crinkling" noise of the burst disc just before it fails!! Then the fun begins!!! The one I removed from the hospital in Fond Du Lac Wisconsin (belonged to Mayo Clinic of Rochester MN) drew a HUGE crowd since they didn't warn anyone of the impending "storm"!!!!
MRI uses big supercooled permanent magnet
Quench removes coolant
Supercooled magnet does not like being warm
Magnet stops working
With the Helium shortage, recovery was not an option??
At the time of this video quenches for decommissioning the magnets were more common.
코난보고온사람.?
저요 ㅋㅋㅋㅋㅋㅋ
@@정우-r9c ㅋㅋㅋㅋㅋㅋ
접니다...
저용
“Where did all our office supplies go?”
a tragedy with one character, and it's not even alive
1:20 the machine's soul escapes to heaven
Music too loud, voice to quiet.
There goes a small Fortune of helium….
any videos soon of it being taken apart?
Oooh. Good question. I don't know the timeline for breakdown, but ill def catch some video of it.
2 years later, no video ☹️
$500,000 worth of damage with one button xD
Yeah...
Is the leaking fluid helium? If so, why is it not recovered?
I'm highly certain that's actually the air liquefying in contact with the extreme cold... to capture helium would not be too hard and they'd have to "vent" it into a tank through a compressor. Same way refrigerant recovery is done once air conditioners and condensing units from walk in coolers need to be retired.
It's a pity that the helium can't be recovered, with it in such short supply.
It absolutely can be recovered. Look up Cryomech. The hospital system MBA dolts aren't able to think beyond 'medicare reimbursement' for ideas on how to save money so it never occurs to them to try He recovery.
@@tetrabromobisphenol I wish this was Reddit so I could award this comment.
They can get more. Nobody bothered mining helium for an entire century because the US had such a huge surplus for airships they never built and were giving it away for practically free. Now that there's economic reasons, there's already been helium found in several likely rock formations.
It'll never be as cheap again, probably. We were profiting from the US' poor decisions.
@@tsm688 Helium isn't produced by the same processes that make oil or natural gas. It's a byproduct of the nuclear decay or uranium and thorium, deep in the earth's crust. It just so happens to gather in gas pockets, which we can extract along with natural gas and oil. The PROBLEM that everybody's worrying about is that we're using that helium at a greater rate than we extract and refine it.
@@tetrabromobisphenol It's cheaper to just let it go than to bring the tanker trucks and multi-stage compressors required to transfer the helium. Sure, you can do it, but it's not economical.
What is that, liquid (now gaseous) nitrogen?
Liquid helium turned back to gas.
Music is too loud...
When it got to the shot on the roof I thought that the mountains in the background look like the Sandias. Was this shot in Albuquerque?
Imagine having a pacemaker or implant and forgetting to tell the doctors then all of a sudden the MRI grabs you and starts thrashing you around while hissing and shooting white smoke
Not what would happen in reality but sounds funny.
That machine looks to serviceable to be retired.
I can only imagine that despite its good condition, the team were legally obliged to decommission it after a specific date.
@@Anthrocarbon It's probably on it's way to a foreign country where the restrictions are not so harsh.
Its a bit like computers. The tech advances quickly such that an older unit becomes obsolete after a decade or two.
Not to mention it's also an accuracy thing. Yes I can weld with a Powerkraft 180 welder from the 60's or a lincoln Powerwave from 2010(ish). Guess which one's more precise.
Probably being replaced by a stronger machine. 0.7T isn't that much these days.
FFR: Pschh, your phone storage won't get erased by magnetism; flash storage works on an entirely different principle.
if people knew what went on inside that machine, they would be a lot more hesitant to get in one
I sure hope that's not true! I think people would generally be pretty excited about the amazing tech that goes into them...
@@DC177E They used to call it NMRI, but the N was dropped because people got afraid that their atomz would fry.
Blimey, my perverted mind surprises me sometimes...
Go read the patents, there is a great deal of information on how they function. did you know the first one was invented in 1974? and they didn't get into hospitals until 1983.
I know what goes on and it's super cool, I've gotten an MRI once before and I'd get one again if I needed it.
$50k worth of liquid helium…
At least...
Nowadays when a magnet is being decommissioned the helium is often recovered though.
I think that the Helium cannot be recovered because you need the latent heat capacity of the Helium to absorb the magnetic energy that is stored in the superconducting coils. If you simply removed the Helium then then coils would heat up and become normal conductors with resistance. Then the large circulating current would dissipate a huge amount of heat in the coil resistance. The coils would become white hot, melt and set fire to the builidng. But this does raise the question of what does quenching actually do? How does it cause the coil temperature to rise above the transition temperature while still allowing the Helium to absorb the energy?
I've often wondered how it works as well... someone else just said, there are He and LN in the cryo chamber. the LN must be there to keep the He from warming up, perhaps, if they vent the LN first, the field collapses very slowly, so you not get the HUGE Back EMF current spike... I'm not sure... interesting...
@@tekvax01 I'm thinking that perhaps they have a big resistor, ie. a heating element, which is also submerged in the Helium and is connected in series with the superconducting coil but is normally shorted out by a switch. Then to quench they open the switch allowing the current to flow in the heater. The heater absorbs the inductive energy dissipating it as heat and the Helium then absorbs the heat as it boils off.
@@petehiggins33 or lots of "huge" snubber diodes to "short out" the back EMF, just like on a motor or induction coil... Science is FUN!
Someone suggested putting a damned weather balloon over the vent. You'd have a hard time heating it sufficiently it wouldn't freeze in crack, but in principle, I'm at a loss trying to find a reason that wouldn't work.
MR engineer here. We can just ramp down the magnet (remove all the current from the super conductive coil) and then the liquid helium can be reclaimed safely and at leisure. But it's not as easy as just quenching the magnet and throwing all the helium away 🤕
Music is too loud to hear your explanation.
This is still most interest video i ever seen youtube.
Got here because of King Of Random and damn does this match his channel name lmfao!!!!!!!!!
So what's the point of retiring an MRI machine if it still works? Or what was the supposed problem with it? And how is one that was vented prematurely get restarted?
Given that liquid helium is getting harder to find and more expensive why not recover it from the machine rather than venting it into the atmosphere? Surly there has to be equipment to do that.
www.reddit.com/r/askscience/comments/36tpuj/could_the_helium_released_from_an_mri_quench_be/
Could be stale helium, past the manufacture date. Kids don't want that crap in their balloons.
@@gavincurtis I swear stores are putting "watered down" helium in balloons these days. The lift force they exhibit feels way less than they did 20 years ago.
*WE ARE NOT* running out of the second most common element in the universe. The *US stockpile* is running dry, yes - the stockpile so massive nobody bothered mining for helium for an entire century. Now that there's money to be made, mining companies have already found helium in several likely rock formations (ones like the US stockpile came from - it didn't come from the atmosphere or elfin magic).
I thought you had to spin down the current in the coil to work on one of those things.....Of course, i suppose dumping the coolant and letting it heat up above superconductivity works too. especially for a decommissioning....shame to see all that helium just get vented to atmo though.....
They actually ramp down the magnet and recover most of the helium nowadays instead of quenching old magnets indeed because of how costly and scarce helium is.
But you can't remove the helium before the magnet coil has properly been ramped down first.
They do know that once Helium is gone.... it's gone.
No it isn't. It's a by product of nuclear fission. There's plenty more where that came from.
@@poppyrider5541 so you are willing to wait a couple of billion years to get some more?
@@poppyrider5541 Not of nuclear fission, but of radioactive decay.
@@Wolfyjinny "nuclear fission power plants" is a thing now, so expect more helium in the future
@@brunoreis221 Yes, about 1.7 billion years in the future, unless they can start separating the helium in space.
Did they get a new one or why they put it out of service? Did they have this open machines for such long time already? Here in Germany they only have a few new machines without that closed tunnel.
The machine was so old, and image quality so bad that referring doctors would specifically request we not scan their patients on it. It happened often enough that the powers that be felt it was time.
Hoof In Mouth Productions LLC Thats crazy this looked like a pretty new machine being being open like it was
Why was Michael Jackson's voice so high? Because He He.
That is so bad, but so good, so you get a thumbs up.
Craig Ferguson would approve
So this is why I wait in the waiting room for so long to get a scan. The Techs are back there doing this.
🤣😂 every dang time
Why not recover the liquid helium being it’s so expensive?
Because the market is always 20 years behind scientific reality. MBAs can only understand economics with a 12 month time horizon. The concept of making a killing 5-10 years down the road simply does not compute for them.
Volcanoes release many times this amount of He before and during eruption. It would be more efficient to develop technology to capture that helium first.
What a vase of valuable helium...
And then everyone's iPhone broke.
The video is old so I'm not sure anyone will ever read this, but here it goes : Radio Tech student here. In MRI lessons, we usually see the more classical "donut" style. I don't recall ever seeing such a machine, so how come is it shaped this way ? And is it also medical use or research purpose ? Like some 7T exists nowadays.
This is an Open bore MRI. Heavily used in the early 2000s for claustrophobic patients.It's limitations are in resolution and signal quality due to it's low magnet strength. In recent years they've made advances that have larger bore sizes without the compromise on quality that have allowed high quality images for our claustrophobic population. So, as in this case, these machines have been phased out.
@@hoofinmouthproductionsllc3470 Very interesting thank you very much ;)
I'm surprised the natural gas industry isn't back on a helium recovery plan, since all the stuff that comes from WWII era reserves collected in that manner are getting pricey.
The fact they still let it be sold for party balloons should be a major clue that the US doesn't GAF.
@@kauske its more that its not as big of an issue as the media is letting it on to be. makes a great headline and spooks not so intelligent people, like yourself.
@@thepjup4507 The fact you result to argumentum ad hominem shows the only 'not so intelligent person' here is you.
If you understood the uses of helium and how it's constantly wasted, plust the realistic limits, you might actually care. But I guess your reasoning is 'I'll be dead before it becomes an issue', right? Just pawn it off on your kids/grandkids like climate change, _right?_
@@thepjup4507 I wonder how many other things you think is 'just the news making a big deal of', I wonder what your sources are for it 'not being a big deal'.
@@matthill5658 You quoted me saying "not being a big deal". Here is the actual quote: "not as big of an issue as the media is letting it on to be". The term 'As big of' is used relatively to compare two different things. Commons sense would deduce, then, that I am not implying, nor did I say "not a big deal". As for the sources, here you go:
physicstoday.scitation.org/do/10.1063/PT.6.2.20200605a/full/
www.gasworld.com/kornbluth-helium-shortage-to-ease-in-2020/2018205.article
www.gasworld.com/helium-oversupply-leads-to-a-pricing-plateau/2020020.article
cen.acs.org/articles/95/i30/helium-way.html
www.researchgate.net/publication/329684204_On_the_opportunities_of_the_shift_of_helium_industry_world_center_to_eastern_Siberia_Russia
I doubt you'll read even one of those, but you asked for sources and there they are. Since it seems you have difficulty picking up on implied information, let me be 100% clear and direct.
Yes, helium is a finite and dwindling resources, and it being completely gone is a big deal. However, it is in no current danger of being depleted, especially for industries that use it. I do believe there should be more sustainable practice with all resources, not only helium, but the helium shortage is indeed being spectacularized by the media.
So, where are your sources saying it's a proven immediate danger?
Jesus. There goes 25.000$ in helium
At least...
So, a quench is simply shutting off the coldhead?
The liquid helium keeps the magnet cold enough to be a "super conductor" that is, the current can just circulate around.
It's not perpetual motion as energy is still required to maintain the extreme cold, but it doesnt require continuous power. In fact you could cut all power for a time without losing the field, just like losing power for a hour or two but the food in your fridge doesnt spoil. It requires much less energy to keep it cool than it would to supply current continuously to a traditional electromagnet.
What the quench button does is intentionally heat the magnet until it loses its superconducting properties. This causes the circulating current to suddenly encounter resistance, causing everything to dramatically heat up. The helium becomes a gas again, and pressure builds until the emergency pressure release device gives way.
It takes a lot of work, a specialized technician and a big tank of liquid helium to energize an MRI magnet, and this process is expensive in itself. Not only that, but the thermal shock of quenching it in this way could damage parts, too. That's why a quench should only be initiated if there's not only an immediate danger to people, but a danger that can be reduced or eliminated by immediately shutting down the field. For example, a person getting pinned against the MRI by a metal object, or if fire and rescue people can rescue someone, or put out a fire, more quickly if the field is gone.
ua-cam.com/video/QwUq8xM_8bY/v-deo.html&ab_channel=DONG
@@dickcheney6 what happens to an NMR if not filled with helium neither nitrogen for about 6 months ?!!
Your mission, Dan/Jim, should you choose/decide to accept it, ...
As always, should you or any of your IM Force be caught or killed, the Secretary will disavow any knowledge of your actions. This tape/disc will self-destruct in five/ten seconds. Good luck, Dan/Jim.
You can litterally see liquid nitrogen and oxygen condensing on the venting tube
Thats helium
helium is inside and vents out, but the tube is frozen bellow condensation point of said gases and so they transfer to liquid state and run down the tube outer surface.
and it also called AIR :)
@@matyasd007 the liquid helium is used to cryogenically freeze the MRI magnets. When it is vented it cools the out side of the vent down. The air which is nitrogen and oxygen then condenses on the vent as well as moisture in the air.
Its water condensate.
all that valuable helium gone. Can it not be filled back into the transport tanks that delivered it?
As far as I understand, recovering the helium is a pretty dangerous and costly procedure, which is why it’s not done
They really just evacuate all that helium to atmosphere?!
lmao, emergency helium evac button
lol
What is the pulsing pneumatic sound in the background?
What a waste of Helium. Folks, once it vents into the atmosphere, it's gone. Earth's gravity can't hang onto it and it is lost to space.
This. We need He. We need it badly. We'll miss it when it's all gone.
just put mouth to the went and capture it
Relax it's not going to disappear anytime soon lol. When they say shortage it's not how you would normally think of it.
@@railgap Plenty of Helium-3 on the moon. Start mining!
Long story short, we are not running out of the second most common element in the universe, this is an economic issue.
Nobody bothered mining helium for an entire century because the US had a stupidly large surplus (for airships they never built). Now that there's money to be made, people have looked for and found helium in several likely rock formations (like where the US surplus came from - they didn't make it from elfin magic.)
Are those the Sandia Mountains in the background?
Not sure what the hell happened except you cut the power.
they hit the button, and it opens a big valve, and vents all the helium and nitrogen from the cryo chamber, once the bore coils have warmed up, it is no longer superconducting and the magnetic field collapses.
Once the superconducting magnet is no longer "superconducting," meaning that it's warmed up above that threshold, all the current in the coils becomes like a giant heater, which flash boils the liquid helium and nitrogen. This has the potential to damage the coils, even when done properly, so it's only done when they absolutely need to.
Is that hospital in Albuquerque, NM?
Yes
@@hoofinmouthproductionsllc3470 If I may ask, which one?
Grade 11 student here. Not really sure what's going on here and cant really hypothesize, nothing in my mind linked MRI machines and helium. Is the helium some sort of refrigerant for the meaty electromagnetic coils? Never looked into MRI functioning principles, but would really love to know. Can anybody provide a basic explanation, maybe refer me to some websites? Thanks.
The magnet in an MRI is an electromagnet meaning it requires an electric charge to be a magnet. There are two ways of doing that, running an electric current thru the magnet during the time you want to use it, or charging the magnet once and keeping it super cold so the charge can remain in the magnet indefinitely. That's where the helium comes in, it's so cold that it keeps the magnet close to absolute zero. Remove the helium, remove the magnetic field. Check Wikipedia, it's actually a pretty good resource, especially for a layman.
When and why would you have to quench a MRI? I know the basics behind superconductors but couldn't you just kill the power to the whole machine?
@@jimbojones806 Killing power to the machine would do jack didly to the electromagnetic feild becaaause the coils are superconductors and require no additional power other than what they where initially charged with.. you pull the plug and the power will just keep circling in the coils keeping the field until the helium heats up allowing the superconductive coils to become resistive again and halting the current. all fine and dandy but that could take a few hours and in an emergency situation one does not have a few hours so, they speed this up by violently ejecting the liquid helium. not very elegant but ain't nobody got time for that.
@@hoofinmouthproductionsllc3470 oOf. I'm not exactly a layman, y'know. :)
I meant basic as in "quantum physics student basic", not "average intelligence" basic. Thanks for the explanation, but could ya maybe step it up a notch or two? I already know all that, I want to know the advanced functioning principles and math and deep science and all that stuff, if you don't mind. :)
@@stephenwilson8150 hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/nmr.html#c1 actually the hyperphysics website is pretty good in general, helped me no end with getting through my degree.
I'm sure there's a perfectly good reason why they aren't pumping out all that immensely expensive helium to reuse later.
Helium is a finite resource. Why not recycle it? Or recover some of it?
It vented to.the atmosphere and it's basically lost forever.
It'd be nice if they'd recovered it, but *WE ARE NOT* running out of the second most common element in the universe. The *US stockpile* is running dry, yes - the stockpile so massive nobody bothered mining for helium for an entire century. Now that there's money to be made, mining companies have already found helium in several likely rock formations (ones like the US stockpile came from - it didn't come from the atmosphere or elfin magic).
why dont they capture the helium out of the quench right back to a balloon or something?
Because the quench system is there for extreme emergencies like someone pinned to the magnet by a large metal object.
In that case there has to be a quick and *reliable* way to kill the field in order to save a life.
And nowadays the helium is often recovered when the magnet is being decommissioned, however at the time of the video quenching it was more common.
*Top 10 saddest anime death scenes*
are they just venting helium?
Absolutely !
Yes it was quite a waste.
Nowadays the helium is often recovered when a magnet is being decommissioned instead of it being vented out like in many videos.
Nice but what's the point of the music? Interferes with the commentary and hides actual sounds. Just Why?!?