Custom Cryocooler Refill Station Project - Page 1
Forum section: electronics / general

author: MrSheep
author_rank: Frequent Contributor
timestamp: April 03, 2025, 03:36:21 pm
content: Hi Everyone,Thought I revisit this topic after some thinking and research. Here is the block diagram as a starting point. Will create a bill of materials soon. As well as more information on the custom refill tool.

author: MrSheep
author_rank: Frequent Contributor
timestamp: April 03, 2025, 03:58:17 pm
content: I only have blurry pictures to work off of but, this is the refill tool Ricor uses. My guess is that they use a valve with a stainless steel tube with a 1/8in hex key at the end of it.The tool screws onto the refill port and probably uses a crush washer (copper or indium?) of some sort to seal it against the metal body.As for the internal design of the operator/valve. It will probably be a high pressure seal or two that allows for rotary and linear movement. High pressure rotary and linear seals from SKF come to mind.

author: LaserSteve
author_rank: Super Contributor
timestamp: April 03, 2025, 08:21:01 pm
content: Might be something similar to this:https://www.cryocomp.com/products/vacuum-valve-operator-v1000-series/Steve

author: MrSheep
author_rank: Frequent Contributor
timestamp: April 03, 2025, 08:23:00 pm
content: Hi Steve,I have that actually haha. They are used on vacuum ports on LN2 Dewars. Probably need the actual fill tool or make a custom one that can handle high pressures.

author: coppercone2
author_rank: Super Contributor
timestamp: April 03, 2025, 08:33:29 pm
content: Looks kinda bad, they have all the floating swagelok. Really you want some tubing braces and bulkhead fittings in a enclosure to make a 'proper' apparatus. I recommend you consider that in your version. Each of those valves should be mounted on a bulkhead.When I made my gas mixer it got a box with bulkhead fittings and properly mounted gauges.. it should look like a test equipment if you make it right IMO. I usually heard some excuse about 'pressure drop' aka I don't wanna buy the right parts when I see this, or learn how to precisely cut and bend the tubing. Be sure to have some mesh walls though, because there could be a concern about a regulator failure causing the chassis to get inflated rapidly. It does take some skill to get it to mount properly to a front panel without stressing parts, if it don't fit you can't just mangle it into place, it has to be disassembled and adjusted or possibly parts need to be remade if you don't have clearances for bending tool. It's not as forgiving as electronics areThose floating constructs can end up getting strange problems because the tubing is never as robust as you think, particularly if you are at 1/4 or even 3/8. It like jangles and there is undue stress on the swages IMO. Or if a valve gets sticky, so it does not torque the pipe work. That is how you get a leak when $1000 of pipes gets 'nudged excessively' and no one wants to fess up that they contacted the tumble weed so it gets covered up and eventually your leaking some where and don't know it.IDK how serious you are with your project but IMO you can do better then that picture, if you are interested in doing so.and I hate 'things' that grow on tanks, one valve and or a reducer should be all it has IMO. Its just bad practice. You can't often get rid of the regulator on the tank because of how they work, it just works better when it has a high pressure supply because of how it regulates, and there is aversion to having high pressure lines going to stuff, it would require a redesign of the whole tank (maybe in the deep future.. but you COULD mount a special bracket on the tank to support the regulator so its not hanging off the valve lol)I understand if you do it that way for one project but a company that servicing them should be betterI saw that before with a stuck trunion, it was like "oh get the pipe wrench to torque that valve attached directly to the regulator on the tank making a big lever...." lovely.. maybe you should tell them to turn the tank off and disconnect the regulator and carefully place it in a flat jaw vise before you do that, but what will happen is someone is just gonna get a wrench and twist the fuckign thing

author: MrSheep
author_rank: Frequent Contributor
timestamp: April 03, 2025, 08:59:17 pm
content: Hi,Thanks for the tips. And this is just a mock up. Nowhere near the finished design. And yes I plan to have it bolted down to something and in some sort of vented enclosure.In terms of the valves. I was just actually modifying my design, only really need one Swagelok valve, near the vacuum side haha. I also plan to use best practices when it comes to bending/installing the fittings. Also in terms of flow/placement of the fittings/regulator/guages, I am open to suggestions.Attached is my updated design. Do note this is an abstract "block diagram" so it's not accurate dimensionally, just a visualization of what is needed, etc.

author: coppercone2
author_rank: Super Contributor
timestamp: April 03, 2025, 09:11:28 pm
content: I think you might wanna put the vac gauge at the end of the flexible hose if you can for a high vacuum. IDK how well it distributes because I never did vacuum work. If you do everything right the flexible hose is the biggest leakerI imagine it might be hard to get it to work on ULV, its alot of jointery. Some people might go with welded pipe hereIf you think a leak will be found by the meter where it is, then leave it where it isJust don't think its fool proof, it can have problems, as expensive as it is. I definitely know some people say full welds or bust for some stuff.and the tubing.. its not all the same.. some people don't check and its OK enough but not what you expect for all applicationsI am not too keen on dealing with that stuff anymore. IDK if brazed copper is suitable but I kinda... trust it a little more... ditch the stainless if its not absolutely necessary.Do you need stainless because of adsorption of gases ?And that is not NPT is it? I had some fun recently doing the HVAC and I would not be happy if that is NPT. IDK what NTP is. I had to use alot of xenomorph resin (comes in elmer glue bottle) to get that NPT to seal OK, what a bastard. If its facing the helium bottle should be OK (isolated by regulator from vacuum), I assume that is what it is

author: MrSheep
author_rank: Frequent Contributor
timestamp: April 03, 2025, 09:31:07 pm
content: I think the vacuum gauge should be fine where it is since the volume isn't that large. The one by Ricor just has a line to the tool, the gauge is probably inside the box.And Swagelok should be ok with high vacuum at least that is what the data sheets say. And yes the tubing will be ultrahigh purity:https://www.swagelok.com/downloads/webcatalogs/en/ms-01-182.pdfThe idea is to have the cleanest possible environment for the gas. 6N UHP Helium is 99.9999% Pure after all haha.And yes the Swagelok Regulator has 2 female NTPshttps://www.swagelok.com/downloads/webcatalogs/en/ms-02-230.pdf

author: coppercone2
author_rank: Super Contributor
timestamp: April 03, 2025, 09:37:20 pm
content: no you need to read between the lines of what im saying I don't think the spec/quality is as tight as a EE would imagine for certain products, particularly tubingthe pipe mill puts alot of HARD WORK into making tubing and its not so easy for them to scrap it, and there is alot that can go wrong. It's like shit from 'the deer hunter' movie, a bit more modern and unionized, but don't expect human nature to change so much. There is a reason some stuff gets welded instead of assuming it will deform correctly.. *cough*the datasheet wank and wishful spec does not end with electronic components front page data sheetbut there is a good chance it might go according to plan, hopefullyImagine what can happen on a large pilger machine doing hot and heavy work on weird alloys designed not to off gas or react more then anything else mechanical and the 50 other process steps. some might say its sometimes scandalous

author: MrSheep
author_rank: Frequent Contributor
timestamp: April 03, 2025, 09:53:26 pm
content: Well you can't really just use any old tubing. It has to be clean and not off-gas anything. There is a reason why the coolers were built in a cleanroom, and you need a minimum of a laminar flow work bench to open/service them. I rather just follow what Swagelok recommends and what is UHV safe. It is not that much tubing anyways. Cost way less than a new cooler.