# US 7,607,319 B2 · Positive displacement expander and fluid machinery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,319 B2 - Document ID: US7607319B2 - Status: Granted - Kind: B2 - Application number: 11/659,193 - Filed: 2005-08-05 - Published: 2008-12-18 - Granted: 2009-10-27 - Earliest claimed: 2004-08-05 - Assignees: Daikin Industries, Ltd. - Inventors: Masakazu Okamoto - Web page: https://patentgrep.com/patent/US7607319B2 ## CPC - F04C 29/042: {by injecting a fluid (injection of fluid for sealing, cooling or lubrication F04C29/0007)} - F01C 1/0215: {where only one member is moving} - F01C 1/322: {with vanes hinged to the outer member and reciprocating with respect to the outer member} - F01C 20/26: using bypass channels - F04C 29/126: {of the non-return type} - F25B 9/008: {the refrigerant being carbon dioxide} - F25B 9/06: using expanders (F25B9/10 takes precedence) - F01C 11/002: {of similar working principle} - F01C 11/004: {and of complementary function, e.g. internal combustion engine with supercharger} - F01C 11/006: {of dissimilar working principle} - F25B 1/04: with compressor of rotary type ({F25B1/005,} F25B1/10 take precedence) - F25B 2309/061: with cycle highest pressure above the supercritical pressure - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS - F01C: ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES (internal-combustion aspects F02B53/00, F02B55/00) - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract When an expansion mechanism (60) having an expansion chamber (62) is equipped with a backflow prevention mechanism (80) to suppress the outflow of fluid from the expansion chamber (62) to a communication path (72), it is possible to reduce dead volume in the expansion chamber (62) during operation with the circulation control mechanism (73,75,76) closed. ## Claims ### Claim 1 A positive displacement expander comprising: an expansion mechanism in which a high-pressure fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path, and the backflow prevention mechanism is disposed closer to the expansion chamber than the circulation control mechanism in the communication path. ### Claim 2 (depends on 1) The positive displacement expander according to claim 1, wherein the backflow prevention mechanism is comprised of a non-return valve. ### Claim 3 A positive displacement expander comprising: an expansion mechanism in which a high-pressure fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path, and the circulation control mechanism is comprised of an electric-operated valve capable of adjusting the degree of opening. ### Claim 4 A positive displacement expander comprising: an expansion mechanism in which a high-pressure fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path, and the circulation control mechanism is comprised of an electromagnetically opening/closing valve capable of opening and closing. ### Claim 5 A positive displacement expander comprising: an expansion mechanism in which a high-pressure fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path, and the circulation control mechanism is comprised of a differential pressure regulating valve which opens when differential pressure between pressure of the fluid during an expansion process in the expansion chamber and pressure on the fluid outflow side is greater than a predetermined value. ### Claim 6 A positive displacement expander comprising: an expansion mechanism in which a high-pressure fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path, and the expansion mechanism is configured to carry out an expansion process of a vapor compression type refrigeration cycle in which the high pressure becomes super-critical pressure. ### Claim 7 (depends on 6) The positive displacement expander according to claim 6, wherein the expansion mechanism is configured to carry out an expansion process of a vapor compression type refrigeration cycle using a CO2 refrigerant. ### Claim 8 A positive displacement expander comprising: an expansion mechanism in which a high-pressure fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path, and the expansion mechanism is configured to be a rotary expansion mechanism in which rotation power is recovered by means of expansion of the fluid. ### Claim 9 A fluid machinery comprising: a positive displacement expander; a motor; and a compressor driven by the positive displacement expander and the motor in order to compress a fluid, the positive displacement expander, the motor, and the compressor being provided in a casing, wherein the positive displacement expander comprises: an expansion mechanism in which the compressed fluid is expanded in an expansion chamber to generate power; a communication path which diverges from a fluid inflow side of the expansion chamber and communicates with a suction/expansion process position of the expansion chamber; and a circulation control mechanism disposed in the communication path for regulating a flow rate of the fluid, wherein the expansion mechanism is provided with a backflow prevention mechanism for preventing the fluid from flowing from the expansion chamber into the communication path.