A compact liquid nitrogen recondenser with a pulse tube cryocooler

A compact liquid nitrogen recondenser with an orifice pulse tube cryocooler has been developed. The recondensation capacity is about 170 cm 3 /h. The orifice pulse tube cryocooler employed in the recondenser is a valved type, and is commercialized by Sumitomo Heavy Industries Limited. The cryocooler delivers a cooling power of more than 10 W at 77 K with a connecting tube of 4 m between the cold head of the cryocooler and a rotary valve unit. An air-cooled helium compressor unit with a rated input power of 1.6 kW is applied for the cryocooler. Excepting the compressor unit and the rotary valve unit, the recondenser is 113 mm in diameter, 567 mm in height, and 6 kg in weight. The recondenser and the cryocooler are handy and flexible for many scientific, medical and industrial applications. This paper describes the design and the test result of the recondenser, as well as the cooling performance of the pulse tube cryocooler.