CHART MVE Fusion, Technical Manual, Page: 13 / 51

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Figure 7: Schematic cross section of Cryocooler
The cryocooler system operates as follows (refer to Figure 7):
1. Helium gas is cyclically compressed and expanded relative to the mean pressure
by the pistons of the PWG.
2. With each forward stroke of the pistons helium gas moves through the first warm
heat exchanger (the “aftercooler”) where heat is removed. Helium is next forced
through the regenerator, which precools the gas before it reaches the cold heat
exchanger (see Error! Reference source not found. ).
3. As the gas moves toward the cold heat exchanger, gas in the acoustic network
(thermal buffer tube, warm heat exchanger, and reservoir) also moves in the same
direction. Even as the driven gas stops advancing, when the pistons reach their
upper limits, the helium gas continues moving in the inertance tube, driven by its
own inertia. This acts like a virtual piston, moving away from the cold exchanger,
expanding the cold gas. As the cold gas expands, it gathers heat from the
surroundings (the area or substance to be cooled).