Luumi may make a new thread when I repair mine. Will take detailed pictures. It's a Union Carbide Dewar. Not 100% sure what the exact repair method will be until I tear it down.
Dont know if anyone cares but if you are bored like me atm then you can watch pretty much all of the new movies and series on InstaFlixxer. I've been binge watching with my gf during the lockdown =)
I SEAL THE ORIGINAL PORT WHERE THE VACUUM IS PERFORMED AND THAT AT THE SAME TIME SERVES AS A SAFETY VALVE IN CASE THAT LIQUID NITROGEN IS IN THE ANNULAR SPACE. IS IT DANGEROUS TO PERFORM THAT KIND OF REPAIR?
Dewar damage depends on handling in transit and copying liquid nitrogen. it is necessary to have a suction pump to facilitate the copying of liquid nitrogen so that the dewar remains safe from shock.
Question Luumi - months ago I was watching a live where Steve GN and Stepongzi were doing some LN2 OC. I heard that LN2 tank is supposed to leak a little bit to avoid too much pressure. Is that right? Or maybe they were talking about the bigger tank? While the size you repaired can/should be closed? Thanks
Yes as there is some loss eventually, so if you close even a normal air pressure dewar it will explode if the gas cant get out. Those big pressureized ones are different.
@@LuumiJuhani I think you need to clarify an important issue. When we speak about a "dewar leak", we're not talking about gas pressure build up in the Liq N2 compartment, we're talking about loss of vacuum in the surrounding insulated tank. If you put that evacuated compartment under deep vacuum, and (while supposedly sealed) expose it to a source of helium, a "leaking Dewar" will show He in the evacuation stream to the RGA or MS. That is a leaking Dewar. The only connection between the inside of a Dewar Vessel and the atmosphere is the opening at the top of the tank! There is always evaporative loss of the cryo fluid from the tank. The most expensive tanks (ie liquid helium) have the best vacuum because of their design, including the seals....
@@LuumiJuhani yeah, that's what I'm experiencing. So, how do I get the plug out of the pump out port? And did you fabricate your own valve from scratch?
@@talmancharters That is the hardest part, to get a suitable valve and get it fixed on a dewar. There are quite a lot of 1/4" threaded valves out there, you have to find out first what is suitable for the vacuum pump you wish to use. One thing you could do is take the dewar to some local hydraylics or similar store as they might have suitable valves and even pumps there.
This type of dewar should hold product for a long time, weeks. Mine was losing an entire tankful within 24 hours. I changed the pressure relief valves, but it still lost it all in 24 hours. I had it re-vacuumed, and the problem was fully solved.
Yeah, I took my 32L dewer into Praxair main midwest hub because I was going to do this mod after I removed the stainless steel ball bearing and they said it is also very important to not only have a safety valve on on the flil neck if using while under pressure ( I do ) but also for the area where the vacuum is pulled. They said as long as you are using o-ring and putty ( not glue or epoxy) that is your safety (along with a cap) , but that a Schrader valve is not designed to hold deep vacuum pull
@@gtijason7853 great value all the same! How long is your 'repaired' dewar able to keep liquid nitrogen? ie, what is the per/day loss in liters? I wonder if a ball bearing seal could still be used? (and remove the shraeder valve fitting after pumping down) Using a cryo pump would also be useful to obtain an even lower pressure, if you have any liquid nitrogen available.
It all depends on the price of the gear. Sometimes vacuum pumps can cost 150-200€ or more so you need to think if it is worth it to buy one. IT is if you are going to repair a few dewars.
@@LuumiJuhani sir give me your email address i have some questions about repair liquid Nitrogen Container repair. I have liquid Nitrogen Container resell business in Bangladesh. But when a liquid Nitrogen is damage i can't repair. So it's very important for me to learn how to repair liquid Nitrogen Container. Please 🙏 help me.
No, it's only a vacuum port. The LN2 dewar itself has an open neck and is always at ambient pressure; at 4:43 you can see that the top has slots so that the cap can't seal. Small 5 liter dewars often have a mushroom-like cap where the stem is foam to loosely plug the neck and reduce heat transfer into the dewar.
Yeah, I took my 32L dewer into Praxair main midwest hub because I was going to do this mod after I removed the stainless steel ball bearing and they said it is also very important to not only have a safety valve on on the fil neck if using while under pressure but also for the area where the vacuum is pulled. They said as long as you are using o-ring and putty ( not glue or epoxy) that is your safety, but that a Schrader valve is not designed to hold deep vacuum pull
@@LuumiJuhani Oh that is just a type of grease and not epoxy / JB Weld ? That should be safe since the valve has an o-ring but Praxair said a Schrader valve won't hold/last under deep vacuum
@@gtijason7853 Yeah it is not epoxy. Epoxy is risky as it is stronger than the outside surface aluminium. That is only to provide extra sealing not to glue it into place.
There is so much wrong with this video that I hardly know where to start. You have sealed shut the over pressure protection plug on the dewar annular space. If the inner vessel develops a leak into the vacuum, the outer shell will now explode rather than pop the plug and vent. Why do you think those o-rings were on that plug? Next you loaded open top dewars that constantly vent into an enclosed vehicle. That's a quick way to create an oxygen deficient atmosphere and either pass out or become disoriented while driving. Next you hand poured LN2 in your sock feet. The Leidenfrost effect tells us that LN2 will roll off of skin at atmospheric temperatures and that is true. However, it will easily become trapped in clothing and cause painful cryogenic burns. As for the modified dewar, no legitimate liquid supplier would fill that once they see the modification. Too much liability. You are a UA-cam hazard.
Wrong, that way of repairing is SAFE because the plug is attached to the outside vessel with that putty. It will give up earlier than cause any explosion. If you screw on a plug then that is dangerous if there is a pressure build up. And don't worry about my LN2 handling. That hole is where they originally suck the vacuum from and then seal it.
@@LuumiJuhani Wrong indeed. I have over 20 years in this industry rebuilding and repairing cryogenic vessels of all types and sizes. You used a Torr Seal equivalent such as JB Weld for the "putty". That has a stronger bond strength than the outer shell aluminum. In either case, the pump out port/burst port should not be modified in any manner and no legitimate gas supplier should fill a dewar that has had any pressure relief function modified. These are lessons our industry has learned from 100 years of cryogenic production.
@@annodam835 I guess that depends on the material that is used. And that vehicle has separate air space at the back so it is completely fine to transport that way.
@@annodam835 The putty I use on the video is very basic putty that is very elastic, I can even peel it off with finger nail. It doesn't have high tensile strength at all and will easily give up if there was a pressure build up and the cap with that valve would just fly off.
Nice! I have a 35L with a bad vacuum. Was researching how to repair recently. So perfect timing!
Sadly the pics of original guide by barbonenet are dead :( . Need him to fix them.
Luumi may make a new thread when I repair mine. Will take detailed pictures. It's a Union Carbide Dewar. Not 100% sure what the exact repair method will be until I tear it down.
@@richiec7700 Did you do this?
Luumi not yet. I'm actually searching for parts and a vacuum pump today. My 20L has a weak vacuum as well.
Very nice. The dewars with smaller ports you can use thick hose with clamps and an A/C port. Great Video.
Dont know if anyone cares but if you are bored like me atm then you can watch pretty much all of the new movies and series on InstaFlixxer. I've been binge watching with my gf during the lockdown =)
@Merrick Cody Yup, I've been using InstaFlixxer for since november myself :)
I SEAL THE ORIGINAL PORT WHERE THE VACUUM IS PERFORMED AND THAT AT THE SAME TIME SERVES AS A SAFETY VALVE IN CASE THAT LIQUID NITROGEN IS IN THE ANNULAR SPACE.
IS IT DANGEROUS TO PERFORM THAT KIND OF REPAIR?
There is no liquid nitrogen in the vacuum space and can not get there. It will not explode.
Dewar damage depends on handling in transit and copying liquid nitrogen. it is necessary to have a suction pump to facilitate the copying of liquid nitrogen so that the dewar remains safe from shock.
nice video, thanks, can you share details of procedure you have done with the blank vacuum port and attaching your own valve?
I will try to get it done in detail soon.
Very informative
Question Luumi - months ago I was watching a live where Steve GN and Stepongzi were doing some LN2 OC.
I heard that LN2 tank is supposed to leak a little bit to avoid too much pressure.
Is that right? Or maybe they were talking about the bigger tank? While the size you repaired can/should be closed?
Thanks
Yes as there is some loss eventually, so if you close even a normal air pressure dewar it will explode if the gas cant get out. Those big pressureized ones are different.
@@LuumiJuhani I think you need to clarify an important issue. When we speak about a "dewar leak", we're not talking about gas pressure build up in the Liq N2 compartment, we're talking about loss of vacuum in the surrounding insulated tank. If you put that evacuated compartment under deep vacuum, and (while supposedly sealed) expose it to a source of helium, a "leaking Dewar" will show He in the evacuation stream to the RGA or MS. That is a leaking Dewar. The only connection between the inside of a Dewar Vessel and the atmosphere is the opening at the top of the tank! There is always evaporative loss of the cryo fluid from the tank. The most expensive tanks (ie liquid helium) have the best vacuum because of their design, including the seals....
I've tried it, because the dewar is leaking at the neck of the dewar. then it must be disassembled and repaired. not just vacuumed.
Hi there, thanks for sharing this ...i have a similiar problem with my container,so how long does it take to re vacuum it??
The actual sucking process with a vacuum pump depends on how fast the pump is in CFM, I let it suck atleast 30 mins.
@@LuumiJuhani i forgot you already editing your movie in a short duration...it seems the whole process very quick,😬, thanks again
Sir, how long will this vacuum pump need to be used for a 4 liter container.
I let it suck this for a few hours.
Sir, what is the name of the new valve vacuum pressure you have used inside this hole?
You can find just simple 1/4" valves quite easilly. Just something that connects to pump.
My tank has a hole in the neck can i glow it and repaire the vaccum what glue can seal it without leakage
Great!
Sir can i visit your plant and i need vakum valve and pum What is the seal being done
Hy ,where are you from?
I suspect I've lost vacuum in my dewar as well...can you describe the symptoms? My tank is constantly venting...it was fine two months ago!!d
Cold temperature on outside wall. Like for example freezing is obvious symptom.
@@LuumiJuhani yeah, that's what I'm experiencing. So, how do I get the plug out of the pump out port? And did you fabricate your own valve from scratch?
@@talmancharters That is the hardest part, to get a suitable valve and get it fixed on a dewar. There are quite a lot of 1/4" threaded valves out there, you have to find out first what is suitable for the vacuum pump you wish to use.
One thing you could do is take the dewar to some local hydraylics or similar store as they might have suitable valves and even pumps there.
This type of dewar should hold product for a long time, weeks. Mine was losing an entire tankful within 24 hours. I changed the pressure relief valves, but it still lost it all in 24 hours. I had it re-vacuumed, and the problem was fully solved.
how low a vacuum did you pull? A schrader valve can't hold a deep vacuum.
Yeah, I took my 32L dewer into Praxair main midwest hub because I was going to do this mod after I removed the stainless steel ball bearing and they said it is also very important to not only have a safety valve on on the flil neck if using while under pressure ( I do ) but also for the area where the vacuum is pulled. They said as long as you are using o-ring and putty ( not glue or epoxy) that is your safety (along with a cap) , but that a Schrader valve is not designed to hold deep vacuum pull
@@gtijason7853 great value all the same! How long is your 'repaired' dewar able to keep liquid nitrogen? ie, what is the per/day loss in liters? I wonder if a ball bearing seal could still be used? (and remove the shraeder valve fitting after pumping down) Using a cryo pump would also be useful to obtain an even lower pressure, if you have any liquid nitrogen available.
Sir I want to learn how to repair the liquid Nitrogen Container. Please help me.
It all depends on the price of the gear. Sometimes vacuum pumps can cost 150-200€ or more so you need to think if it is worth it to buy one. IT is if you are going to repair a few dewars.
@@LuumiJuhani sir give me your email address i have some questions about repair liquid Nitrogen Container repair. I have liquid Nitrogen Container resell business in Bangladesh. But when a liquid Nitrogen is damage i can't repair. So it's very important for me to learn how to repair liquid Nitrogen Container. Please 🙏 help me.
@@AbdurRahim-gp2yq My email is on my youtube profile. Send me email I can share some knowledge.
hi, could you tell me where I find this valve that you used to repair and what is this glue? Thanks
You can use pretty much any 1/4" valve, the valve doesn't have to hold high pressure as it is only going to be for vacuum.
The stuff is not really a glue, just some very elastic putty so that the plug remains as the weakest part of the outer surface.
The vacuum evacuation port have two functions. one as evacuation for pumping and the other is a safety device... whats about this?
No, it's only a vacuum port. The LN2 dewar itself has an open neck and is always at ambient pressure; at 4:43 you can see that the top has slots so that the cap can't seal.
Small 5 liter dewars often have a mushroom-like cap where the stem is foam to loosely plug the neck and reduce heat transfer into the dewar.
Yeah, I took my 32L dewer into Praxair main midwest hub because I was going to do this mod after I removed the stainless steel ball bearing and they said it is also very important to not only have a safety valve on on the fil neck if using while under pressure but also for the area where the vacuum is pulled. They said as long as you are using o-ring and putty ( not glue or epoxy) that is your safety, but that a Schrader valve is not designed to hold deep vacuum pull
How much value vacum?
The pump was over 100 years back when I bought it. A stronger pump is recommended.
How long you used vaccum pump ?
Once it hits zero so lowest possible pressure I left it still on for at least 30 mins.
My 50L statebourne is broke, not sure where its died though :(
Oh crap, hardest one is if there is a hole inside the dewar, that is really hard and almost impossible to repair.
Can you please advise me on the glue name that you used for sealing the valve
It is not really a tough glue, just some putty that is very elastic.
@@LuumiJuhani Oh that is just a type of grease and not epoxy / JB Weld ? That should be safe since the valve has an o-ring but Praxair said a Schrader valve won't hold/last under deep vacuum
@@gtijason7853 Yeah it is not epoxy. Epoxy is risky as it is stronger than the outside surface aluminium. That is only to provide extra sealing not to glue it into place.
Do you know tha valves name or whre can I find it?
Well you can find many 1/4" Valves from hydraylics stores. You could go to some of those stores for example and ask there.
You see main a 2 liter nitrogen gas cylinder repair
Vacuum pump required me
Kha hota yh
I have to try,,, this is fake...
IT IS NOT, I use the dewar once every 2 months. New video will come later.
@@LuumiJuhani I've tried it, because the dewar is leaking at the neck of the dewar. then it must be disassembled and repaired. not just vacuumed.
Vcumpamp
There is so much wrong with this video that I hardly know where to start. You have sealed shut the over pressure protection plug on the dewar annular space. If the inner vessel develops a leak into the vacuum, the outer shell will now explode rather than pop the plug and vent. Why do you think those o-rings were on that plug? Next you loaded open top dewars that constantly vent into an enclosed vehicle. That's a quick way to create an oxygen deficient atmosphere and either pass out or become disoriented while driving. Next you hand poured LN2 in your sock feet. The Leidenfrost effect tells us that LN2 will roll off of skin at atmospheric temperatures and that is true. However, it will easily become trapped in clothing and cause painful cryogenic burns. As for the modified dewar, no legitimate liquid supplier would fill that once they see the modification. Too much liability. You are a UA-cam hazard.
Wrong, that way of repairing is SAFE because the plug is attached to the outside vessel with that putty. It will give up earlier than cause any explosion. If you screw on a plug then that is dangerous if there is a pressure build up. And don't worry about my LN2 handling.
That hole is where they originally suck the vacuum from and then seal it.
@@LuumiJuhani Wrong indeed. I have over 20 years in this industry rebuilding and repairing cryogenic vessels of all types and sizes. You used a Torr Seal equivalent such as JB Weld for the "putty". That has a stronger bond strength than the outer shell aluminum. In either case, the pump out port/burst port should not be modified in any manner and no legitimate gas supplier should fill a dewar that has had any pressure relief function modified. These are lessons our industry has learned from 100 years of cryogenic production.
@@annodam835 I guess that depends on the material that is used. And that vehicle has separate air space at the back so it is completely fine to transport that way.
@@annodam835 The putty I use on the video is very basic putty that is very elastic, I can even peel it off with finger nail. It doesn't have high tensile strength at all and will easily give up if there was a pressure build up and the cap with that valve would just fly off.
I agree with you 💯