Hughes Aircraft Company

Joseph L Hlava

Matthew M Skertic

Nevil Q Maassen

Arthur A Eneim

Roy B Hasselquist

H Burt Warner

An airborne cryogenic cooling system in which a first cryogenic material located within an on-board container is cooled to the solid state prior to launch a remotely located second cryogen conduited to the container. Immediately prior to becoming airborne connection is broken to the second cryogen and on-board cooling is achieved by venting the container to space environment causing sublimation of the solid first cryogenic, or, alternatively, the container may be left sealed and cooling results from triple-point transition of the solid cryogen.

Cryogenic cooling system for airborne use

A dewar (20) useful in rapidly cooling a sensor (28) supported thereon includes a bore tube assembly having a cylindrical dewar bore tube (22) with an end cap (24) at one end to close the bore tube (22). The bore tube assembly is cooled by directing a stream of coolant at the interior of the end cap (24). The sensor (28) is mounted directly to the exterior surface of the end cap (24). A cold shield (34) partially encloses the sensor (28). A cold shield support bracket (38) mounts the cold shield (34) to the cylindrical side walls of the dewar bore tube (22) at a mounting location (36) axially displaced from the end cap (24) and therefore less effectively cooled than the end cap (24), so that heat is extracted from the support bracket (38) and the cold shield (34) less rapidly than from the sensor (28). From an uncooled starting condition, the sensor (28) is cooled to its operating temperature, and the cold shield (34) is cooled to its operating temperature, in about the same time.

Rapid cooldown dewar

A two-stage Joule-Thomson cryostat (10) has a first-stage cryostat (12) with a helical-coil heat exchanger (14) and and isenthalpic gas expansion orifice (20) that discharges a mixture of cooled gas and cryogenic liquid into a liquid cryogen plenum (26). A second-stage cryostat (30) with a helical coil heat exchanger (32), wound to a larger diameter than the first-stage heat exchanger coil (14), is wound around and in thermal contact with the liquid cryogen plenum (26). This arrangement achieves a high degree of interstage heat transfer and cooling of the gas flowing in the second-stage heat exchanger coil (32) by the liquid cryogen in the first-stage liquid cryogen plenum (26). In operation, a gas flow management system (60), designed for rapid cooldown, initially passes a first gas of high specific refrigerating capacity through both stages (12 and 30). When the stages and structure are sufficiently cooled to the near-vicinity of the normal boiling temperature of the first gas, the flow of the first gas through the second-stage cryostat (30) is discontinued, and flow of a second gas of lower normal boiling temperature than the first gas is passed through the second stage cryostat (30). The flow of the first gas continues through the first-stage cryostate (30).

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Woodland Hills, CA, United States of America

Joseph L Hlava