Check out this link for a detailed description of the "Stirling Cycle" in particular the YouTube video at the bottom of the article is very well done and shows a small machine in operation:
https://www.stirlingcryogenics.eu/en/the-stirling-cycle Tom On Sun, Oct 2, 2022 at 1:41 AM Paul Koning <paulkon...@comcast.net> wrote: > > > > On Sep 30, 2022, at 11:19 PM, Tom Hunter <ccth6...@gmail.com> wrote: > > > > https://www.stirlingcryogenics.eu/ > > > > These machines are still made and indeed are very cool. ;-) > > So to speak! > > I didn't see their liquid helium machine. I remember one installed at the > TU Eindhoven physics department; it consisted of a pair of two-stage > Stirling machines (which by themselves will liquify hydrogen or neon, i.e., > they go down to about 20 K) plus a bunch of auxiliary equipment. The whole > setup took maybe a 15 foot square room. > > The website doesn't show any of the compact machines I remember seeing > described. A bunch of those had 400 Hz power, indicating they were meant > for airborne use. One was a little lab bench machine, a box perhaps the > size of an old style desktop PC, lying flat, with a "cold finger" sticking > out of the box. > > paul > >
