Seligman's plate heat exchanger (first commercially available type, 1923) with 6 plates Seligman's plate heat exchanger
A.P.V. "Junior Paraflow" plate heat exchanger, size 1a, free standing (1972) A.P.V. "Junior Paraflow" plate heat exchanger 1972
Early Collins type expansion engine used in helium liquefiers, by The British Oxygen Company Limited, England, 1970-75. Collins' Expansion Engine from Helium Liquefier, 1970-75 1970-1975
Partially cutaway model of a gas-bearing cryogenic turbo expander, and a complete miniature rotor for the turbine, by The British Oxygen Company Limited, England, 1974. Cryogenic Expansion Turbine from Gas Liquefier, 1974 1974