Oil-cooled gas compressor

Patent metadata

Field	Value
Publication number	US-9441638-B2
Application number	US-201113818841-A
Country	US
Kind code	B2
Filing date	Aug 8, 2011
Priority date	Aug 27, 2010
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

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.

First claim

What is claimed is:

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, the oil-cooled gas compressor further comprising:
an air-cooled heat exchanger for cooling the oil flowing through said oil pipe;
a cooling fan with a controllable rotational frequency for sending cooling wind to said air-cooled heat exchanger;
a waste-heat-recovery heat exchanger, being provided upstream of said air-cooled heat exchanger, in which the oil flowing is heat-exchanged with cooling fluid flowing for recovering heat from the oil flowing through said oil pipe; and
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 a manner such that temperature of the compressed gas discharged from said compressor body falls within a prescribed range in accordance with the temperature detected by said discharge temperature sensor, and
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.

2. The oil-cooled gas compressor according to claim 1 , wherein said air-cooled heat exchanger and said waste-heat-recovery heat exchanger are serially connected to said oil pipe or said gas pipe.

3. The oil-cooled gas compressor according to claim 2 , further comprising:
a gas temperature sensor detecting temperature of the compressed gas exiting from said waste-heat-recovery heat exchanger; and
an oil 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 gas and oil temperature sensors and the compressor discharge temperature detected by said discharge temperature sensor.

4. 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 the oil and gas pipes.

5. The oil-cooled gas compressor according to claim 1 , wherein said oil-cooled gas compressor is an oil-cooled screw air compressor.

6. 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.

7. The oil-cooled gas compressor according to claim 6 , 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.

8. The oil-cooled gas compressor according to claim 6 , 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.

9. The oil-cooled gas compressor according to claim 8 , further comprising a controller controlling the oil change-over valve based on running water information detected by said running water detecting sensor.

10. The oil-cooled gas compressor according to claim 6 , 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 fluid temperature sensor.

11. The oil-cooled gas compressor according to claim 10 , further comprising a controller controlling said oil change-over valve based on temperature information from said fluid temperature sensor provided at said circulation pipe.

12. The oil-cooled gas compressor according to claim 10 , wherein a plurality of said waste-heat-recovery equipment are connected in parallel with said circulation pipe, and are selectively connected based on the temperature information from said fluid temperature sensor.

13. 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, the oil-cooled gas compressor further comprising:
an air-cooled heat exchanger for cooling the oil flowing through said oil pipe;
a cooling fan with a controllable 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, in which the oil flowing is heat-exchanged with cooling fluid flowing 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, and
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.

14. The oil-cooled gas compressor according to claim 13 , 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.

15. The oil-cooled gas compressor according to claim 13 , wherein said air-cooled heat exchanger and said waste-heat-recovery heat exchanger are serially connected to said oil pipe or said gas pipe.

16. The oil-cooled gas compressor according to claim 14 , further comprising:
a gas temperature sensor detecting temperature of the compressed gas exiting from said waste-heat-recovery heat exchanger; and
an oil 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 gas and oil temperature sensors and the compressor discharge temperature detected by said discharge temperature sensor.

17. The oil-cooled gas compressor according to claim 13 , wherein said compressor body, said oil separator, and said air-cooled heat exchan

Assignees

• Takano Masahiko
• Tanaka Hideharu
• Hitachi Industry Equipment Systems Co Ltd

Inventors

• Takano Masahiko
• Tanaka Hideharu

Classifications

• F04C18/16

  with helical teeth, e.g. chevron-shaped, screw type {(for non-parallel axes of movement F04C18/48)} · CPC title

• F04C2270/195

  Controlled or regulated · CPC title

• F25B31/004

  oil recirculating arrangements · CPC title

• F04C2240/81

  Sensor, e.g. electronic sensor for control or monitoring · CPC title

• F04C29/04 Primary

  Heating; Cooling (of machines or engines in general F01P); Heat insulation (heat insulation in general F16L59/00) · CPC title