# US 12,760,940 B2 · Dual helium compressors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,760,940 B2 - Document ID: US12760940B2 - Status: Granted - Kind: B2 - Application number: 17/481,099 - Filed: 2021-09-21 - Published: 2022-01-06 - Granted: 2026-10-13 - Earliest claimed: 2015-12-18 - Assignees: Sumitomo (Shi) Cryogenic of America, Inc. - Applicants: Sumitomo (SHI) Cryogenics of America, Inc. - Inventors: Eric Robert Seitz; Stephen Dunn; Ralph C. Longsworth - Web page: https://patentgrep.com/patent/US12760940B2 ## CPC - F25B 9/06: using expanders (F25B9/10 takes precedence) - F25B 1/00: Compression machines, plants or systems with non-reversible cycle (F25B3/00, F25B5/00, F25B6/00, F25B7/00, F25B9/00 take precedence) - F25B 9/002: {characterised by the refrigerant} - F25B 9/14: characterised by the cycle used, e.g. Stirling cycle - F25B 2339/047: Water-cooled condensers - F25B 2400/075: with parallel compressors - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## 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. ## Claims ### Claim 1 A method to maintain operation of a Gifford McMahon (GM) refrigerator system operating at cryogenic temperatures during a disruption of cooling by using a compressor system supplying gas to an expander and being cooled with either water or air, said compressor system comprising: an air cooled compressor having a first supply side and a first return side, wherein the air cooled compressor contains oil and further includes a pressure equalization valve that equalizes pressures within the air cooled compressor to prevent migration of the oil to the expander, and the pressure equalization valve opens to avoid having high pressure gas in the air cooled compressor blow the oil in the air cooled compressor back through the first return side when the air cooled compressor turns off, a water cooled compressor having a second supply side and a second return side, wherein the water cooled compressor contains oil and further includes a pressure equalization valve that equalizes pressures within the water cooled compressor to prevent migration of the oil to the expander, and the pressure equalization valve opens to avoid having high pressure gas in the water cooled compressor blow the oil in the water cooled compressor back through the second return side when the water cooled compressor turns off, and wherein the oil contained in the water cooled compressor is kept separate from the oil contained in the air cooled compressor, a gas supply manifold connected to the respective supply side of each compressor and a high pressure side of the expander, a gas return manifold connected to the respective return side of each compressor and a low pressure side of the expander, wherein the gas return manifold is configured to prevent gas from flowing from the air cooled and water cooled compressors toward the gas return manifold, a plurality of check valves formed on the gas return manifold to prevent the gas from flowing from either compressor into the gas return manifold, a plurality of sensors to detect critical operating parameters connected to a controller, the controller operating the expander at rated capacity with either one of the compressors on and the other off and during the period when one compressor is being turned on and other compressor is being turned off, the method comprising: operating one of the air cooled and water cooled compressors for the operation of the GM refrigerator system; determining, via the controller, whether the operation of the operating compressor has failed based on outputs from the sensors located inside the operating compressor; and turning, via the controller, the operating compressor off before or after turning the other compressor on, when the operation of the operating compressor has failed. ### Claim 2 (depends on 1) The method of claim 1 wherein said turning the operating compressor off before or after turning the other compressor on comprises turning the operating compressor off before turning the other compressor on. ### Claim 3 (depends on 1) The method of claim 1 wherein said turning the operating compressor off before or after turning the other compressor on comprises turning the other compressor on before turning the operating compressor off. ### Claim 4 (depends on 1) The method of claim 1 wherein said determining whether the operation of the operating compressor has failed comprises: receiving signals from the plurality of sensors; and determining sensors among the plurality of sensors, which provide signals that are used to determine when to switch from the operating compressor to the other compressor. ### Claim 5 (depends on 1) The method of claim 1 wherein the plurality of sensors include temperature sensors configured to detect temperatures. ### Claim 6 (depends on 1) The method of claim 1 further comprising keeping the expander operating if at least one of the air cooled and water cooled compressors is turned on. ### Claim 7 A method to conserve energy in maintaining an interior of a building at a temperature in a range of 15 to 30° C. and providing redundancy in a Gifford McMahon (GM) refrigerator system that is operating at cryogenic temperatures by using a compressor system supplying gas to an expander, said compressor system comprising: an air cooled compressor having a first supply side and a first return side, wherein the air cooled compressor contains oil and further includes a pressure equalization valve that equalizes pressures within the air cooled compressor to prevent migration of the oil to the expander, and the pressure equalization valve opens to avoid having high pressure gas in the air cooled compressor blow the oil in the air cooled compressor back through the first return side when the air cooled compressor turns off, a water cooled compressor having a second supply side and a second return side, wherein the water cooled compressor contains oil and further includes a pressure equalization valve that equalizes pressures within the water cooled compressor to prevent migration of the oil to the expander, and the pressure equalization valve opens to avoid having high pressure gas in the water cooled compressor blow the oil in the water cooled compressor back through the second return side when the water cooled compressor turns off, and wherein the oil contained in the water cooled compressor is kept separate from the oil contained in the air cooled compressor, a gas supply manifold connected to the respective supply side of each compressor and a high pressure side of the expander, a gas return manifold connected to the respective return side of each compressor and a low pressure side of the expander, wherein the gas return manifold is configured to prevent gas from flowing from the air cooled and water cooled compressors toward the gas return manifold, a plurality of check valves formed on the gas return manifold to prevent the gas from flowing from either compressor into the gas return manifold, and a plurality of sensors to detect critical operating parameters connected to a controller, the controller operating the expander at rated capacity with either one of the compressors on and the other off and during the period when one compressor is being turned on and other compressor is being turned off, the method comprising: locating both of the air cooled and water cooled compressors inside the building for operation of the GM refrigerator system; comparing temperature outside the building and temperature inside the building; and operating one of the air cooled and water cooled compressors, to operate the GM refrigerator system, based on the comparison between the temperature outside the building and the temperature inside the building, comprising: operating the water cooled compressor and operating the GM refrigerator system with the water cooled compressor, when the temperature outside the building is greater than the temperature inside the building; operating the air cooled compressor and operating the GM refrigerator system with the air cooled compressor, when the temperature outside the building is less than the temperature inside the building; and switching to the nonoperating compressor in response to a failure of the operating compressor.