Sciencemadness Discussion Board

Operating a Cryogenic Cooler (Rigaku AL60) without the control units

SuperOxide - 13-3-2023 at 11:11

I've been looking to get a cryogenic cooler for a while now. The ability to make my own LN2 would be pretty awesome, however, they're usually out of my price range.
I did however find a Rigaku AL60 Cryocooler on Ebay for a very reasonable price, but the seller knows pretty much nothing about it or if it even works. And it's just the cryocooler (no control or power units).

An alternative would be to buy a "complete unit" that includes the cryocooler itself as well as the control units for it. Here's an example, also an AL60 being sold on Ebay.
Now, as much as I would love to buy the 2nd listing, $3k is just too much to spend right now, and I don't think the seller is willing to ship it anyways (which would cost me an arm and a leg).

So, I think the best route would be to buy just the "head unit" (ie: the AL60 cryopump in the first listing above), and try to power/control it without the control units that typically come with it. I'm certain this can be done as I've seen a few neat videos of it on YouTube:

  1. Veritasium using just the heat pump powered by a variac
  2. Applied Science powering the cryocooler with a bench top power supply but controlling it with his laptop and a circuit board.

Question: Does anyone have any experience powering/controlling a cryocooler without the power/control units it usually comes with? Im sure it's not as simple as just wiring it up to my Variac or DC bench power supply.
If I can find a way to test the AL60 cryocooler without having to buy the other parts, then I would feel more comfortable about buying the cryocooler from the first seller, as I could test it and return it if it doesn't work. It would just suck to buy it and have to wait to find a cheaper control unit to test it, just to find out that it's broken, lol.

Any help would be greatly appreciated.
Thanks!

Edit: I think the AL60 units I linked to may work a little differently than the units that can be powered/operated just using a Variac. I don't think the AL60 is a sterling based head. It has some connectors for high/low pressure (helium maybe?), which isn't found in the heads I see used in some videos.

[Edited on 13-3-2023 by SuperOxide]

yobbo II - 13-3-2023 at 15:33


You could try contacting the manufacturers who may be helpful. It may require a simple power supply. I don't have a clue I will admit.

Would the high low connections just be an air compressor of some sort.

There are other ways of generating LN2 with a high pressure pump like

https://www.ebay.com/itm/374513124114?_trkparms=amclksrc%3DI...

Thats not answering your question though.

Yob

[Edited on 13-3-2023 by yobbo II]

Rainwater - 13-3-2023 at 15:34

With great difficulty. A quick google turned up nothing useful except it requires a 2kw driver.

So what you have is a linear actuator. The drive voltage, pulse width, and frequency will have to be varied during the operation of the unit by using feedback from the motor controller and cold-end temperature.

When starting the unit from room temperature, low power low frequency will be used to limit the compression ratio inside the piston chamber.

As the cold end cools, the internal pressure will drop, requiring more power and faster speed to bring the pressure back up and maintain cooling effect.

Even an experienced vfc technician will not be able to build a controller from scratch without more information.

You should reach out to the manufacturer

Rainwater - 14-3-2023 at 03:09

I was way off
https://en.m.wikipedia.org/wiki/Cryocooler search for the gm style
Manufacturer site
https://www.cryomech.com/cryocoolers/gifford-mcmahon-cryocoo...
You need a compressor as speced in the site above.
Basicly all thats in the head is a valve you control which feeds the high pressure line into the displacement head.
You can use dry co2 free air, but will suffer performance issues
once you reach the temperature of liquid oxygen you risk damage do to liquid formation within the device

Sulaiman - 14-3-2023 at 05:49

Before such a significant but uncertain investment
I would check the cost of an occasional LN2 delivery.

Deathunter88 - 14-3-2023 at 09:33

These heads require the external unit to work because that is the compresser for the helium gas. The stirling cryocoolers in the two videos are self contained and so work very differently. Even with your second listing, you still need a source of pure helium gas and a vacuum pump to recharge the lines.

SuperOxide - 14-3-2023 at 12:06

Quote: Originally posted by Deathunter88  
These heads require the external unit to work because that is the compresser for the helium gas. The stirling cryocoolers in the two videos are self contained and so work very differently. Even with your second listing, you still need a source of pure helium gas and a vacuum pump to recharge the lines.

Yep, that's what I realized after posting this. I think I'll hold off and wait for a self contained unit to be listed. I'm sure those are much more expensive though.

SuperOxide - 15-3-2023 at 13:48

So, I actually forgot about Bens blog post where he went over his setup more in depth.
He states:
Quote:
Stirling cryocoolers are not relatively common devices, but they are used for RF filters that contain superconducting components. Such RF filters with their integrated cryocoolers can be found on eBay for under $300. One particular unit is the Superfilter built by Superconductor Technologies Inc. It contains a cryocooler that is rated at 140 watts of input power, and is extensively documented here (http://books.google.com/books?id=POLgG5mma6IC&pg=PA75).
I purchased the Superfilter on eBay and extracted the cryocooler.


FInding one on ebay for $300 would be a Godsend. Honestly, I would even pay twice that amount.
The full RF filter device he pulled the pump out of was similar to one found here: https://xdevs.com/article/sti/

I have an ebay seller trying to pitch a sterling cycle cryocooler that can liquify N2 pretty easily.



Just a small caveat in that it's over $16k >_<

If anyone can sell me a self contained sterling cycle cryocooler that can liquify liquid nitrogen, I would be willing to pay cash, very quickly as well.

Thanks.