Abstract: A d.c. motor together with a hot gas bypass valve is incorporated into a cooling system specifically designed for removing heat from computer systems. Unlike typical refrigeration systems, the cooling system herein runs continuously and responds to changes in thermal load. This allows the unit to operate within a wide range of ambient conditions and at various thermal load levels unlike other systems which were capable of operation only at a single, predesigned load level. The cooling system is modular and is easily added to or removed from a redundant system which includes a single evaporator with multiple refrigerant loops which provides yet another aspect of continuous operation due to the inherent redundancy thus provided.

Abstract: A d.c. motor together with a hot gas bypass valve is incorporated into a cooling system specifically designed for removing heat from computer systems. Unlike typical refrigeration systems, the cooling system herein runs continuously and responds to changes in thermal load. This allows the unit to operate within a wide range of ambient conditions and at various thermal load levels unlike other systems which were capable of operation only at a single, predesigned load level. The cooling system is modular and is easily added to or removed from a redundant system which includes a single evaporator with multiple refrigerant loops which provides yet another aspect of continuous operation due to the inherent redundancy thus provided.

Abstract: A device is provided for passing a member through the wall of a sealed chamber. The member has an outer surface having a portion thereof which is substantially formed of metal. A flange has an opening therein which surrounds and is spaced from the metal portion of the member. A solder member completely fills the space between the flange opening and the metal portion of the member for creating a seal therebetween which is capable of maintaining a high pressure differential between opposite sides of the sealed chamber wall. The member is preferably a flat, multi-conductor electrical cable having thin, flat, copper shielding layers on the top and bottom thereof. The metal portion preferably includes a wedge-shaped copper member which surrounds the electrical cable and is intricately affixed to the shielding layers. The solder member is preferably a solder compound comprising 52 percent indium and 48 percent tin.

Abstract: A gasket is fabricated with electrical flex cables extending through the gasket in order to electrically communicate from the outside of a vacuum chamber with the electrical devices positioned within a vacuum chamber of a cryogenically cooled module. The gasket is fabricated from elastomeric, dielectric materials such as neoprene to effect a seal between the portions of the vacuum chamber and also to seal between the gasket material and the conductors of the flex cables which pass through the gasket.

Abstract: A cryocooled field-replaceable logic unit for use with a cryogenic cold head such as that of a cryocooler comprises a thermally conductive plate adapted to be disposed in thermal contact with the cold head, a thermally insulating enclosure portion cooperating with the conductive plate to form a sealed enclosure detachable from the cold head, and one or logic chips mounted in the enclosure in thermal contact with the conductive plate. Preferably the conductive plate is attached to the thermally insulating portion through a resilient mounting which forms a recess for receiving the cold head and which is tension-loaded when the logic unit is mounted on the cold head to urge the plate into intimate thermal contact with the cold head. In one embodiment the enclosure receives from an external source a supply of gaseous nitrogen which is liquified by contact with the conductive plate to form a pool of liquid nitrogen in which the logic chips are immersed.