cold acceptor in cold head for cryocooler

Discussion on Stirling or "hot air" engines (all types)
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yaku98
Posts: 3
Joined: Sat Jan 26, 2019 1:53 am

cold acceptor in cold head for cryocooler

Post by yaku98 » Sat Jan 26, 2019 2:19 am

Dear friends,

I am new comer, I working on a Beta style cryocooler which cold head reside at one end.
I would like to know your comments on the position of cold acceptor in cold head related to displacer furthest reaching point.
Normally furthest reaching point of displacer is less than top end of cylinder, say 5 mm. The lowest edge of cold acceptor reside 12mm below the top end, that is to say the cold acceptor overlap with displacer stroke 7mm.
Feel free to give your opinion. Thank all for your valuable opinion.

Yaku

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: cold acceptor in cold head for cryocooler

Post by Ian S C » Wed Jan 30, 2019 2:22 am

The coldest part is the area that in a hot air engine would be the heated part, you need to take care of the cooling area too, because this gets quite hot. Good luck, it's fun trying.
Ian S C

Trevor
Posts: 209
Joined: Sun Nov 06, 2016 4:07 am

Re: cold acceptor in cold head for cryocooler

Post by Trevor » Sat Feb 02, 2019 1:24 am

Hi Ian & Yakka
Reference to your observation of a person using the cold water from gas.
I built a nice Beta motor for a friend just recently and we had all sorts of problems with the gas container going so cold that the motor would stop due to very little heat caused from bottle getting to cold and freezing the gas.
We solved this problem by wrapping the water cooling pipes around the gas bottle. AS the Sterling was pumping water through the model the heated water was then cooled by the gas bottle and of course the gas bottle was getting warmer so the gas heat would work again.
Trev

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: cold acceptor in cold head for cryocooler

Post by Ian S C » Sat Feb 02, 2019 2:39 am

Trev, Back in the 1990s there was a bit in Model Engineer very similar problem with the gas container on a STIRLING ENGINE freezing, also the cooling system was not quite keeping up. The cure was to part submerge the gas tank in the cooling water, then getting the balance between hot and cold, the water heating the gas bottle, while the gas bottle cooled the water. The motor involved was a pressurized one.

Ian S C

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