New colleagues, new burner and progress on gas analysis system | week 8-9/2022
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- Опубліковано 6 бер 2022
- It's been 6 months since the last video - wow! Time is merciless..
In this video, I want to moments from the last two weeks - testing a new burner for H tube and updates from the gas analysis system.
Thank you for watching!
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Thank you, looks like you are solving problems faster than new ones arrive, and are making great progress.
I am not that sure, but at least I am glad I make that impression :-)
@@daliborfarny New challenges every time, and you are making great progress. Look at your first tubes and your latest, they are worlds apart.
Finally got the chance to watch this. Thanks for putting these videos out. I've been following you guys since the early days.
It's good to have you back
Always brightens my day to see you post a new video
those Unitorches are a weird beast. I have a love/hate relationship with mine. it definitely frees up a hand when you might otherwise be using crossfires and two hand torches at the same time. I understand the struggle to get a narrow heat band on large diameter tube.
Dont put the scroll pump the same table as the turbo. The vibration will shorten the turbo's life. Bad bearings can cause oscillation in the rotational speed too.
Good info! We will make a rack later - with some vibration dumping
Excellent machining work on that chuck... turning that big chunk of steel on such a small lathe shows a machinist with more skills than I could ever hope to have.
Part of that work was done on a bigger lathe - but a lot on that small one :-)
Your analysis system is faulty - but not for the reason you think. I'll outline two points:
1 - By butting the tube up against the glass like that, and sealing the _outside_ with epoxy, you're creating the mother of all virtual leaks, which will significantly impact your RGA readings. If you really want to do this right, you should just seal a short piece of tube to the envelope at the creation stage, without blowing through(i.e. a second "blind" evacuation tube), and then half-drill it.
Alternatively, the way this is generally done is outlined in #2.
2 - If you have a long-term sealed, self-contained system, the way to create an analysis port is by adding a second, open tube with a glass-to-metal adapter(i.e CF1.33), connected directly to a UHV-specific valve(see below). You evacuate and fill the system as normal, and then when time comes, you connect it to the RGA and simply open the valve. This also raises another issue - if you just _dump_ all the gas from the tube into the RGA, you'll get completely garbage readings. If you want to do a single-shot analysis from a sealed volume(i.e., get more resolution), you need something to seriously restrict the flow. This is usually done with something called a "variable leak valve", which you can also use as a long-term sealing element when closed. You can find them on eBay for a few hundred euros, just make sure the sapphire/diamond flat is not damaged. Or brand new, for around 600-900.
Oh, and for turbo controllers, just switch to open loop operation when you reach a certain margin. When I designed mine, if the speed was within 5Hz, I just locked it to the set speed and a minimum current(adjusted by hand). If it dropped, then I went back in sync.
Cool! 2. We have a metering valve there to restrict the flow, with diy teflon seat to seal off completely - I am not sure if it will work - we will see! 1. We will need to analyze random faulty tubes, old tubes from 70s etc - so we cannot make a special flange on it. But I am aware of the risk of making virtual leaks this way. Also, we might need to add one more turbo on that part - kind of loadlock system to evacuate faster.. Thank you for your inputs - it will be interesting to see how it works in real life..
Turbo - exactly, this is how Radim solved it in the end..
@@daliborfarny The professional solution for this, is a fracture cell or fracture chamber. I saw one at Tungsram (now GE) a hungarian light bulb manufacturer's lab. They put the bulb in a chamber, then they pumped down the chamber, then they closed the pumping line, then they fractured the glass with a similar magnetic thingy, then they let the gas enter to the analysis chamber through a leak valve. Ask PreVac (a company in Poland) to be your supporter, they can easily make one for you. :)
@@altxyz That solution would be problematic for testing already finished tubes - they contain plastics, glues etc.. in the socket. And the main point is to test tubes that for some reason failed - these always come with the socket. Also, such a custom built commercial device is not within our budget.
Fantastic work by an amazing team, Bravo!
Absolutely fascinating. Always look forward to your updates.
Amazing how far you have come since starting videos.
Looks like the glass will need some normalising after the joint to reduce the stress.
Thanks for the updates!
Thanks for the update, your videos are always so enjoyable.
It's great to have another video! And good to see that progress is coming along with the various projects. I hope the next video won't be quite as far away, but I understand if you time is needed for more important things. Best of luck to you and the team for the projects you're currently working on!
I dont want to promise anything - but I am adjusting my schedule so I can make a summary every two weeks. ;-)
good to see all the good work! Very nice! Greetings to the family.
...krásná práce...radost se dívat...
Great content folks.
The progress you all are making is wonderful to see! Thank you for investing time to create such a video, it is positive news.
Wow, that is a cool custom chuck. I dare no to think how expensive that piece of Teflon must have been...
Also great to hear that you are working on the "freezing" bug. I noticed it two times in the last weeks on my clock, but I did not think much of it.
It was around 35 EUR, not cheap - but the work is more expensive :-) yes, the freezing bug is the priority #1 for this week!
My Puri-6 clock also freezed twice last week!
Cool things you do! thanks for video!
Thank you!
Luv ur work!
So good to see you back in a video ! Your progress are fascinating, thanks a lot for sharing so much details. Take care !
By the way, to go below 10^-7, are ion pumps or neg coatings to be consider in your case?
Good to have you back sir! I will soon build one of your clocks!
Such good videos! Keep up please!
It's so inspiring to see how long you've gone with this endeavour :)
Wow, soo many new things happening . The RGA setup with a hammer to puncture the tubes is really ingenious!
Amazing well done. Keep up the good work 👍
Ať se Vám daří!
In regards to the stresses in the glass, i wonder what would happen if you'd use a 5th hand on the bottom burner that's pointed such that the flame is fanned out towards the base of the tube, angled up (so it doesn't interfere with your work). That way, even if you do have stress in the glass, it's less pronounced into on spot. Regardless, normalizing seems to be something you'll need to consider, that's a pretty sharp demarcation line on the glass.
Source: a few years back we needed to test various concrete formulas against sea water and we ordered specific lab equipment out of glass. A sharp demarcation line caused most of it to crack as the heat cycling tests began. The glass manufacturer said they fixed it by "fanning out the heat pattern". I assume that's what they did in situ (the complicated glass to metal ports kinda blocked any potential normalizing process).
Scientists and masters at work 👍👍👍👍👍
I was reading all the questions about "can you anneal the glass?" and your answers with reasons that doesn't work because the heat will oxidize the internal elements, and I had a "probably a bad idea but it might work" thought: There isn't much physical contact between the envelope (in the areas where you'd want to heat it) and the internal elements, so in principle you should be able to maintain a temperature difference between them. I wonder if you could flow a cooler gas through the inside of the tube to cool the internal elements while heating the envelope. It shouldn't take a lot to keep the grids cool....
Of course, there is probably a simpler solution too. :)
I like the bgm music.
Thanks
Congratulations, your machinist is an artist. An elegant solution for sealing the top covers on the tube. Ideally there would be no stress point. However it is all on the side and uniform now. That’s a huge milestone. Are you going to live with the stress demarcation point as is or are you going to try and feather it out more? Hopefully it will be fine as is. Let us know how it goes.
Good to finally see how Radim looks like ☺️
😁
Please upload videos more frequently.
Thanks.
Nádherné video jako vždycky je neuvěřitelné na kolik problémů a faktorů je potřeba brát ohled ale věřím že výsledek bude za tu námahu stát těším se až to uvidím.
Jenom bych dával pozor na tu turbomolekulární vývěvu správně by se neměla pouštět mimo vakuum kvůli tomu aby se nepoškodily ložiska.
Díky! Tady tento kus je jen k testování, vyřazen právě kvůli vadným ložiskům..
8:40 You most likely noticed it but the rotor turned the wrong way there.
I assume time spent in an annealing oven would cause more oxidation - so is not a solution to the build up in stress in the glass?
thats the problem - annealing would burn the internal elements. Normally, it would be a clean solution!
@@daliborfarny Yes. Inert gas ovens are available - but large ones look expensive. It's too late now, but I wonder if the tube enclosure had been designed so that the seam to be welded was at the intersection of the large cylindrical section and the tapered section - rather than the front glass and the large cylindrical section - whether that would have caused less heat to be absorbed by the internal elements. The large disc of metal at that end of the stack of elements is already a dark colour - and may have protected the numbers from most of the heat. Good luck finding a solution.
This is really HIGH Tech....
I saw, the ceramic cups and plates are burned in oven to eliminate stress inside material. Maybe, H-tubes are need to be burnet in oven too?
Really cool that you're able to create complex, high-precision tools like that! Were you a machinist prior to venturing into Nixie tubes, or is this just picked up over time?
I think the purging gas should be injected as far forward as possible an escape to the back. This way the gas is always flushing away the oxygen. How the construction is now, the gas will move to the front as long as there is not enough seal, but at some point the gases from the flame will not be removed from the front, and this is the moment when left over oxygen reacts with the internals.
Dobrý den Dalibore, nechat nás půl roku o takovém půstu 🙂 měl sem celkem strach že se Vám v rodině nebo v týmu stalo něco nedobrého a popravdě sem se i bál mejlem zeptat jestli je vše v pořádku. Jak se mi ulevilo když 22 února přišel hromadný email 🙂 Co dodat k videu? jako vždy zase obrovský kus perfektně odvedené práce. Ta teflonová kleština super. Doufám že další video nebude až o prázdninách 🙂
I wonder if a hydrogen flame might reduce the oxidative process, you could run it quite rich to deoxidise things.
Of course then you would have more lovely hydrogen to pump down :-)
I wonder, could you anneal during the bake out phase? You're pulling a vacuum then so no oxygen to worry about and you're already in an oven? Just now it needs 500c "easy" lol.
500C is limit - above that the mercury dispensers will release mercury to vacuum.. and we need 560C to anneal..
@@daliborfarny ahh that's a pain in the butt.
Привет! Когда же вы наконец сделаете лампу наподобии ИН-23 для написания текста.
hi, maybe my question is stupid. What is the lifespan of these tubes? Is it possible that need to refill with gases? If yes it is technically possible or after a certain time the tube will not function anymore?
Although I don't have a Nixie tube from Dalibor, I have a clock built with the Z566M, it has been running without stopping since 2008 and so far I have not seen any signs of wear.
I am curious, do all this equipment would be usable to build amplifier tubes? Some tubes are getting rare or difficult to find and I was wondering if you could build such electronic components
Is there a price point for a 4 digit clock?
10:07 200V is WAY to high for this pump, it should be around 70V.
Have you tried tempering the glass tubes?
Take the glass up to 620 C and then cool it no faster than 30 C per hour
@@nethoncho Thats the problem, at this temperature, the internal elements will burn out or get heavily oxidized..
@@daliborfarny I don't know. I'm not familiar with the properties of glass. But maybe you can relieve internal stresses with ultrasonic treatment?
I think you have to find a "think outside the box" solution...