Abstract: This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. This invention provides redundancy between water cooling and air cooling if there is a blockage in the water or air supply by having air and water cooled after-coolers in series or parallel.

Abstract: An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. A valve connecting the warm end of the cylinder to a buffer tank allows a partial expansion and recompression of gas in the cold displaced volume that increases the refrigeration produced in each cycle with the same compressor flow rate.

Abstract: A cryogenic expander maximizes the energy absorbing capacity of bumpers that prevent the displacer or piston in a pneumatically driven expander from hitting the cold or warm end of a cylinder. A collar at the warm end of the piston which has the same outside diameter as the piston and a lip at the warm end that engages an “O” ring before the piston hits the cold end or bottom of the cylinder. The warm end of the collar also engages an “O” ring before the pistons hits the warm end or top of the cylinder. Having “O” rings that are near the maximum diameter of the cylinder maximizes the amount of energy they can absorb, and thus permits quiet operation of larger size expanders than prior designs.

Abstract: This invention relates generally to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) cycle. This invention provides redundancy between water cooling and air cooling if there is a blockage in the water or air supply by having air and water cooled after-coolers in series or parallel.

Abstract: This invention provides a means to start an oil lubricated air cooled helium compressor at ambient air temperatures in the range from ?30° C. to 0° C. by heating the oil in the sump and opening one or more by-pass valves that allows oil to flow to the oil injection port of the compressor without passing through all of the after-cooler.

Abstract: This invention relates to oil lubricated helium compressor units for use in cryogenic refrigeration systems, operating on the Gifford McMahon (GM) or Brayton cycle. The objective of this invention is to provide redundancy by having a water cooled compressor manifolded to an air cooled compressor and sensors to detect faults so that an expander can be kept running if there is a failure in either the water or air supply.

Abstract: A hybrid expander for producing refrigeration at a cryogenic temperature includes a Brayton expander producing refrigeration at a first temperature; a GM expander producing refrigeration at a second temperature, the first temperature being colder than the second temperature, the second temperature being 200K or less. A high pressure line receives a gas from a compressor at a first pressure and supplies it at the first pressure to the Brayton expander and the GM expander simultaneously. A low pressure line returns the gas to the compressor at a second pressure from the Brayton expander and the GM expander, the first pressure being greater than the second pressure. The Brayton expander piston is attached to the cold end of the GM expander displacer and the Brayton expander piston and the GM expander displacer reciprocating together.

Abstract: A high separation efficacy, compact, bulk oil separator oriented horizontally and used with a scroll-type oil-lubricated compressor unit adapted to compressing helium. The horizontal bulk oil separator contains an integral oil reservoir and removes more than 99.9% of the oil from the helium that exits. The bulk oil separator contains successive chambers where oil separates from the gas by impingement.

Abstract: The problems of reducing the torque required to turn the valve, eliminating wear dust, and extending the life of the valves in Gifford McMahon (G-M) type multi-port pulse tube refrigerators are solved by using a rotary spool valve having radial clearance to control flow to and from the regenerator, and using face seal ports on the end of the spool to control flow to and from the pulse tubes.

Abstract: An improved method of reducing wear dust and torque required to turn a multi-port rotary disc valve utilizes a thrust bearing to hold the valve seat and/or valve disc such that they are not in contact with each other, or have light contact each other.

Abstract: The problems of reducing the torque required to turn the valve, eliminating wear dust, and extending the life of the valves in Gifford McMahon (G-M) type multi-port pulse tube refrigerators are solved by using a rotary spool valve having radial clearance to control flow to and from the regenerator, and using face seal ports on the end of the spool to control flow to and from the pulse tubes.

Abstract: A magnetic shield is mounted in its own vacuum enclosure in a regenerative type expander comprising a vacuum enclosure, magnetic material in a cold regenerator, and a magnetic shield, where the magnetic shield surrounds the magnetic material.

Abstract: A cryopump cooled by a GM type refrigerator is disclosed in which the cold (second stage) cryopanel(s) are in planes that are pitched parallel to the axis of the expander cylinder; the cold end of the first stage expansion space is close to the point where the expander cylinder enters the vacuum housing that contains the cryopanels; and a drain system removes all the liquid argon and water flowing out through a vent port for two orientations of the cryopump.

Abstract: A high separation efficacy, compact, bulk oil separator oriented horizontally and used with a scroll-type oil-lubricated compressor unit adapted to compressing helium. The horizontal bulk oil separator contains an integral oil reservoir and removes more than 99.9% of the oil from the helium that exits. The bulk oil separator contains successive chambers where oil separates from the gas by impingement.

Abstract: The present invention applies to single or two stage pulse tube refrigerators that have one or more passive orifices at the hot end(s) of the pulse tube(s) through which gas flows to achieve phase shifting and the phase shifting gas flow circulates to a remote heat sink by adding check valves and an appropriate piping circuit.

Abstract: The pulse tubes (165, 175) and regenerators (160, 170) contained within a cryopump housing (210) are arranged in a way that facilitates the fabrication and installation of the cryopanels (265). The pulse tubes and regenerators are located in a common plane in the center of the cryopump housing and the cold (second stage) panels (265) that are pitched parallel to the plane with the tubes.

Abstract: This invention provides an improved means of quickly warming a pulse tube (165) by shifting the phase relation of flow to the warm end of the pulse tube relative to flow to the warm end (117) of the pulse tube relative to flow to the warm end of the regenerator (160) using a “four valve” concept and the “active buffer” concept. Several different pulse tube configurations and valve timing relations that are effective at reversing the cycle from the normal mode, which produces cooling at the pulse tube heat station, to a reverse mode that produces heating are disclosed.

Abstract: An integrated cryopump and 2 stage pulse tube refrigeration system (100) comprising a cryopump, a compressor for a pulse tube refrigerator, a pulse tube refrigerator located within the vacuum chamber of the cryopump where the hot ends of the pulse tubes (165,175) are connected to each other through a buffer volume (180), are integral to the cryopump vacuum chamber hosing, and a buffer volume (180) is connected to the hot ends (117,119) of the pulse tubes (165,175) through flow restrictors (145,150).

Abstract: An integrated cryopump and 2 stage pulse tube refrigeration system (100) comprising a cryopump, a compressor for a pulse tube refrigerator, a pulse tube refrigerator located within the vacuum chamber of the cryopump where the hot ends of the pulse tubes (165,175) are connected to each other through a buffer volume (180), are integral to the cryopump vacuum chamber hosing, and a buffer volume (180) is connected to the hot ends (117,119) of the pulse tubes (165,175) through flow restrictors (145,150).

Abstract: Several layers of fine mesh screen are diffusion bonded together to form a rigid disc or plate that is self supporting and is a flow smoother at the ends of a pulse tube expander. Layers range from fine screens on the surface facing the pulse tube to coarser screens that provide structural support without significantly adding to pressure drop across the screen assembly. The flow smoother is typically used in series with a heat exchanger at the warm end that rejects heat to ambient from the gas of the pulse tube and a heat exchanger at the cold end that receives heat from the load being cooled.