Conveners
C2Or3A: Non-Aerospace Coolers V: GM and Pulse Tube Coolers
- Carl Kirkconnell (West Coast Solutions)
- Stephen Dunn (Sumitomo (SHI) Cryogenics of America, Inc.)
The terminating network of low-frequency pulse tube refrigerators consists of a reservoir and main orifice valve. Taken together, these components represent an acoustic impedance that determines how much acoustic power is delivered from the compressor to the refrigerator. The volume of the reservoir, flow resistance of the valve, and frequency of the acoustic oscillations are today chosen by...
Closed-cycle cryocoolers have become an important cooling tool for scientific research at low temperatures [1]. Among the family of regenerative cryocoolers, GM-type pulse tubes (PTC) in particular stand out because they have no moving mechanical parts at cryogenic temperatures. This characteristic makes them ideal candidates for cooling vibration-sensitive applications that also require...
Cryomech has been continuously improving the cooling capacities and energy efficiencies of its 4.2 K two-stage pulse tube cryocoolers. The 2.7 W at 4.2 K two-stage pulse tube cryocooler (Model PT425) was developed and introduced by Cryomech in 2021, which, at the time, was the largest, commercially available, 4 K pulse tube cryocooler. Our newest model, the PT450, has been successfully...
Traditional Gifford-McMahon cryocoolers are operated with an integrated rotary valve which regulates the compressed Helium supply and return into the cold head. Theory predicts that 50% of the input energy is lost in this rotary valve. In this work we removed the rotary valve from a Sumitomo RDK-101G cold head and drove the Gifford-McMahon cryocooler in Stirling mode directly with a...
In order to meet the requirements of weight, vibration, and size in the field of infrared imaging, Lihan Cryogenics has developed a lightweight and compact free-piston Stirling cooler, which weighs only 260g (with built-in electronic controller and active balancer). The cooler system consists of a gas-bearing moving magnet compressor and a low-temperature rod-less displacer. This is also...
The pulse tube cooler has the advantages of low vibration, high reliability, and no moving parts at the cold end. However, the poor phase modulation capability and acoustic power dissipation in the phase shifter limit the improvement of its efficiency. Lihan Cryogenics has reported the development of a Stirling pulse tube cooler using ambient displacers. The cooler consists of a moving magnet...
GM cryocooler is characterized by high refrigeration efficiency and high reliability. Its mature manufacturing line makes it widely used in the temperature zone below liquid helium, such as MRI and cryopump. However, the cooling performance of the cryocooler will be weakened by the secondary flow and the natural convection when the cryocooler is installed horizontally. The influence of...
