# US 11,112,148 B2 · Vapor compression system with refrigerant-lubricated compressor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,112,148 B2 - Document ID: US11112148B2 - Status: Granted - Kind: B2 - Application number: 16/320,802 - Filed: 2017-08-10 - Published: 2019-06-13 - Granted: 2021-09-07 - Earliest claimed: 2016-08-26 - Assignees: Carrier Corporation - Applicants: Carrier Corporation - Inventors: Scott A. Nieforth; Vishnu M. Sishtla - Web page: https://patentgrep.com/patent/US11112148B2 ## CPC - F25B 31/002: {Lubrication} - F04D 29/063: specially adapted for elastic fluid pumps - F25B 31/004: {oil recirculating arrangements} - F25B 2339/0242: having tubular elements - F25B 2339/047: Water-cooled condensers - F25B 2500/16: Lubrication - F25B 2700/04: Refrigerant level - F25B 2700/151: of the compressor motor - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) ## Abstract A vapor compression system (20; 400; 420) comprises: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126) from the heat rejection heat exchanger to the compressor; a second lubricant flowpath (121, 126) from the heat absorption heat exchanger to the compressor; at least one lubricant pump (190); and a controller (900) configured to control lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on a sensed fluctuation. ## Claims ### Claim 1 A vapor compression system (20; 400; 420) comprising: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126) from the heat rejection heat exchanger to the compressor; a second lubricant flowpath (121, 126) from the heat absorption heat exchanger to the compressor; at least one lubricant pump (190); a controller (900); and one or more valves (186, 187) controlled by the controller to selectively switch lubricant flow between the first lubricant flowpath and the second lubricant flowpath; wherein: the controller (900) is configured to control the one or more valves (186, 187) to control lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on a sensed fluctuation. ### Claim 2 (depends on 1) The system of claim 1 wherein: the at least one lubricant pump is shared by the first lubricant flowpath and the second lubricant flowpath; and the system comprises a pressure sensor (192) positioned to measure an outlet pressure of the at least one lubricant pump. ### Claim 3 (depends on 1) The system of claim 1 wherein: the sensed fluctuation is a sensed fluctuation in an outlet pressure of the at least one lubricant pump. ### Claim 4 (depends on 1) The system of claim 1 wherein: the at least one lubricant pump is shared by the first lubricant flowpath and the second lubricant flowpath; and the system comprises a vibration sensor (193) positioned to measure a vibration of the at least one lubricant pump. ### Claim 5 (depends on 1) The system of claim 1 wherein: the compressor comprises an electric motor (28); and the first lubricant flowpath and the second lubricant flowpath extend to bearings (36) of the motor. ### Claim 6 (depends on 1) The system of claim 1 wherein the one or more valves comprise: a first valve (186) controlled by the controller along the first lubricant flowpath; and a second valve (187) controlled by the controller along the second lubricant flowpath. ### Claim 7 (depends on 1) The system of claim 1 wherein: the system is a chiller. ### Claim 8 (depends on 1) A method for using the system of claim 1, the method comprising: running the at least one lubricant pump to drive a lubricant flow along one of the first lubricant flowpath and the second lubricant flowpath and not the other of the first lubricant flowpath and the second lubricant flowpath; and responsive to the controller sensing a threshold of said fluctuation, the controller switching to running the at least one lubricant pump to drive a lubricant flow along said other of the first lubricant flowpath and the second lubricant flowpath and not said one of the first lubricant flowpath and the second lubricant flowpath. ### Claim 9 (depends on 8) The method of claim 8 further comprising: after having commenced the running of the at least one lubricant pump, commencing running the compressor to drive a flow of refrigerant sequentially through the heat rejection heat exchanger, an expansion device, and the heat absorption heat exchanger. ### Claim 10 (depends on 8) The method of claim 8 wherein: the switching comprises controlling at least one valve while continuously running the at least one lubricant pump. ### Claim 11 A vapor compression system (440; 480) comprising: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126) from the heat rejection heat exchanger to the compressor; a first pump (190) along the first lubricant flowpath; a second lubricant flowpath (121, 126) from the heat absorption heat exchanger to the compressor; a second pump (191) along the second lubricant flowpath; and a controller configured to stop the first pump after starting the second pump and stop the second pump after starting the first pump. ### Claim 12 (depends on 11) The system of claim 11 further comprising: a first liquid level switch (180) associated with the first pump; and a second liquid level switch (181) associated with the second pump. ### Claim 13 (depends on 12) The system of claim 12 wherein the controller (900) is configured to: responsive to the first liquid level switch indicating low, stop the first pump and start the second pump; and responsive to the second liquid level switch indicating low, stop the second pump and start the first pump. ### Claim 14 (depends on 13) The system of claim 13 wherein: the first liquid level switch is upstream of the first pump; and the second liquid level switch is upstream of the second pump. ### Claim 15 (depends on 11) A method for using the system of claim 11, the method comprising: running the first pump to drive a lubricant flow along the first lubricant flowpath; and switching to running the second pump to drive a lubricant flow along the second lubricant flowpath. ### Claim 16 (depends on 15) The method of claim 15 further comprising stopping the first pump after starting the second pump. ### Claim 17 (depends on 15) The method of claim 15 further comprising: after having commenced the running of at least one of the first pump and the second pump, commencing running the compressor to drive a flow of refrigerant sequentially through the heat rejection heat exchanger, an expansion device, and the heat absorption heat exchanger. ### Claim 18 A vapor compression system (20; 400; 420) comprising: a compressor (22) having a suction port (40) and a discharge port (42); a heat rejection heat exchanger (58) coupled to the discharge port to receive compressed refrigerant; a heat absorption heat exchanger (88); a first lubricant flowpath (120, 126) from the heat rejection heat exchanger to the compressor; a second lubricant flowpath (121, 126) from the heat absorption heat exchanger to the compressor; at least one lubricant pump (190); and a controller (900) configured to control lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on a sensed fluctuation, the sensed fluctuation being a sensed vibration of the at least one lubricant pump or a sensed current drawn by an electric motor of the at least one lubricant pump. ### Claim 19 (depends on 18) The system of claim 18 wherein: the controller (900) is configured to control the at least one lubricant pump or, if present, one or more valves to control the lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on output of the sensed fluctuation. ### Claim 20 (depends on 18) The system of claim 18 further comprising: one or more valves to control the lubricant flow along the first lubricant flowpath and the second lubricant flowpath, wherein: the controller (900) is configured to control the at least one lubricant pump or the one or more valves to control the lubricant flow along the first lubricant flowpath and the second lubricant flowpath based on output of the sensed fluctuation.