# US 2013/0156548 A1 · Oil-Cooled Gas Compressor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156548 A1 - Document ID: US20130156548A1 - Status: Published application - Kind: A1 - Application number: 13/818,841 - Filed: 2011-08-08 - Published: 2013-06-20 - Earliest claimed: 2010-08-27 - Assignees: Hitachi Industrial Equipment Systems Co., Ltd. - Inventors: Masahiko Takano; Hideharu Tanaka - Web page: https://patentgrep.com/patent/US20130156548A1 ## CPC - F04C 29/04: Heating; Cooling (of machines or engines in general F01P); Heat insulation (heat insulation in general F16L59/00) - F25B 31/004: {oil recirculating arrangements} - F25B 43/02: for separating lubricants from the refrigerant - F04C 18/16: with helical teeth, e.g. chevron-shaped, screw type {(for non-parallel axes of movement F04C18/48)} - F04C 2240/81: Sensor, e.g. electronic sensor for control or monitoring - F04C 2270/195: Controlled or regulated - F05B 2260/20: Heat transfer, e.g. cooling - Y02P 80/15: On-site combined power, heat or cool generation or distribution, e.g. combined heat and power [CHP] supply - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract An oil-cooled gas compressor provided with: a compressor body (3); an oil separator (6) that separates out oil from a compressed gas; a gas pipe (8) for sending the compressed gas, from which oil has been separated out by the oil separator, to a user; and an oil pipe (7) for returning, to the compressor, the oil separated out by the oil separator. The following are also provided: an air-cooled heat exchanger (13) for cooling the aforementioned oil; a controllable-speed cooling fan (14) for blowing cooling air at said air-cooled heat exchanger; and a waste-heat-recovery heat exchanger (10), provided upstream of the air-cooled heat exchanger, for recovering heat from the oil flowing through the abovementioned oil pipe. The speed of the cooling fan is controlled so as to bring the temperature of the compressed gas discharged from the compressor body to within a prescribed range. This makes it possible both to recover waste heat from the oil heated by being used to cool the compressor, and to suppress compressor temperature fluctuations even if the load on the waste-heat-recovery equipment varies. ## Claims ### Claim 1 An oil-cooled gas compressor comprising: a compressor body; an oil separator separating out oil from compressed gas discharged from said compressor body; a gas pipe for sending, to a user, the compressed gas separated from the oil by said oil separator; and an oil pipe for returning, to said compressor, the oil separated by said oil separator, oil-cooled gas compressor further comprising: an air-cooled heat exchanger for cooling the oil flowing through said oil pipe; a cooling fan being capable of controlling rotational frequency for sending cooling wind to said air-cooled heat exchanger; and a waste-heat-recovery heat exchanger, being provided upstream of said air-cooled heat exchanger, for recovering heat from the oil flowing through said oil pipe, wherein the rotational frequency of said cooling fan is controlled in a manner such that temperature of the compressed gas discharged from said compressor body falls within a prescribed range. ### Claim 2 (depends on 1) The oil-cooled gas compressor according to claim 1, further comprising a discharge temperature sensor detecting temperature of the compressed gas discharged from said compressor body, wherein the rotational frequency of said cooling fan is controlled in accordance with the temperature detected by said discharge temperature sensor. ### Claim 3 (depends on 2) The oil-cooled gas compressor according to claim 2, wherein said air-cooled heat exchanger also cools compressed gas flowing through said gas pipe, and said waste-heat-recovery heat exchanger also recovers heat from the compressed gas flowing through said gas pipe. ### Claim 4 (depends on 3) The oil-cooled gas compressor according to claim 3, wherein said air-cooled heat exchanger and said waste-heat-recovery heat exchanger are serially connected to said oil pipe or said gas pipe. ### Claim 5 (depends on 4) The oil-cooled gas compressor according to claim 4, further comprising: a temperature sensor detecting temperature of the compressed gas exiting from said waste-heat-recovery heat exchanger; and a temperature sensor detecting temperature of the oil exiting from said waste-heat-recovery heat exchanger, wherein the rotational frequency of said cooling fan is controlled in accordance with the temperature of the compressed gas and the oil detected by said temperature sensors and the compressor discharge temperature detected by said discharge temperature sensor. ### Claim 6 (depends on 1) The oil-cooled gas compressor according to claim 1, wherein said compressor body, said oil separator, and said air-cooled heat exchanger are stored in one housing to form a compressor unit, said waste-heat-recovery heat exchanger is stored in another housing to form a waste-heat-recovery unit, and said compressor unit and said waste-heat recovery unit are connected together with pipes. ### Claim 7 (depends on 1) The oil-cooled gas compressor according to claim 1, wherein said oil-cooled gas compressor is an oil-cooled screw air compressor. ### Claim 8 (depends on 1) The oil-cooled gas compressor according to claim 1, further comprising: an oil bypass pipe for flowing the oil exiting from said oil separator directly to said air-cooled heat exchanger without flowing the oil to said waste-heat-recovery heat exchanger; and an oil change-over valve changing over the oil from the oil separator between flow to said waste-heat-recovery heat exchanger and flow to said oil bypass pipe. ### Claim 9 (depends on 8) The oil-cooled gas compressor according to claim 8, further comprising: a gas bypass pipe for flowing the compressed gas exiting from said oil separator directly to said air-cooled heat exchanger without flowing the compressed gas to said waste-heat-recovery heat exchanger; and a gas change-over valve changing over the compressed gas from said oil separator between flow to said waste-heat-recovery heat exchanger and flow to said gas bypass pipe. ### Claim 10 (depends on 8) The oil-cooled gas compressor according to claim 8, wherein said waste-heat-recovery heat exchanger is connected to a circulation pipe for guiding fluid from an external waste-heat-recovery equipment and returning the fluid subjected to heat exchange to said waste-heat-recovery equipment, and the circulation pipe includes a running water detecting sensor. ### Claim 11 (depends on 10) The oil-cooled gas compressor according to claim 10, further comprising a controller controlling the oil change-over valve based on running water information detected by said running water detecting sensor. ### Claim 12 (depends on 8) The oil-cooled gas compressor according to claim 8, wherein said waste-heat-recovery heat exchanger is connected to a circulation pipe for guiding fluid from an external waste-heat-recovery equipment and returning the fluid subjected to heat exchange to said waste-heat-recovery equipment, and said circulation pipe includes a temperature sensor. ### Claim 13 (depends on 12) The oil-cooled gas compressor according to claim 12, further comprising a controller controlling said oil change-over valve based on temperature information from said temperature sensor provided at said circulation pipe. ### Claim 14 (depends on 12) The oil-cooled gas compressor according to claim 12, wherein a plurality of said waste-heat-recovery equipment are parallelly connected to said circulation pipe, and are selectively connected based on the temperature information from said temperature sensor.