Editing Cryocooler (section)

== Pulse-tube refrigerators ==
[[Image:Schematic pulstuberefridgerator.jpg|class=skin-invert-image|300px|thumb|Fig.7 Schematic diagram of a Stirling-type single-orifice PTR.]]
{{main|Pulse tube refrigerator}}
A so-called Stirling-type single-orifice PTR is represented schematically in Fig.7. From left to right it consists of: a piston which moves back and forth; a heat exchanger X<sub>1</sub> (after cooler) where heat is released at room temperature (''T''<sub>a</sub>) to the environment; a regenerator; a heat exchanger X<sub>L</sub> at low temperature (''T''<sub>L</sub>) where heat is absorbed from the application; a tube, often called the pulse tube; a heat exchanger X<sub>3</sub> to room temperature (''T''<sub>a</sub>); a flow resistance (orifice); a buffer volume, in which the pressure ''p''<sub>B</sub> is practically constant.