Oil-cooled screw compressor system and oil-cooled screw compressor

Patent metadata

Field	Value
Publication number	US-9568001-B2
Application number	US-201214428099-A
Country	US
Kind code	B2
Filing date	Sep 14, 2012
Priority date	Sep 14, 2012
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

In a housing 20 of an oil-cooled screw compressor 10 , a separation gas supply path 59 through which separation gas is supplied to a separation gas supply gap 58 defined between a first seal unit and a second seal unit of a seal device 50 , and a pressure balancing path 60 through which an area closer to a screw chamber 20 a than the first seal unit in a discharge side seal chamber 20 d communicates with a compression chamber at a pressure higher than an intake pressure and lower than a discharge pressure, are defined. A check valve 62 that restricts a flow of a fluid in a direction from the screw chamber 20 a to the discharge side seal chamber 20 d is disposed in the pressure balancing path 60.

First claim

The invention claimed is:

1. An oil-cooled screw compressor system comprising:
an oil-cooled screw compressor;
a tooth surface lubricating fluid supply system that supplies a tooth surface lubricating fluid to the oil-cooled screw compressor;
a bearing lubricating fluid supply system that supplies a bearing lubricating fluid to the oil-cooled screw compressor, in addition to the tooth surface lubricating fluid; and
a separation gas supply system that supplies separation gas different from target gas compressed by the oil-cooled screw compressor to the oil-cooled screw compressor, wherein the oil-cooled screw compressor includes:
a housing in which a screw chamber, discharge side seal chambers connected to one end of the screw chamber, intake side seal chambers connected to the other end of the screw chamber, bearing chambers in communication with the screw chamber via either the discharge side seal chambers or the intake side seal chambers, respectively, a tooth surface lubricating fluid flow path through which the tooth surface lubricating fluid is supplied to the screw chamber, and a bearing lubricating fluid flow path through which the bearing lubricating fluid is supplied to the bearing chambers, are defined;
male and female screw rotors each including: a screw that is disposed in the screw chamber and forms a compression chamber; and shafts that coaxially extend from both ends of the screw to be disposed in the discharge side seal chambers and intake side seal chambers and the bearing chambers;
a plurality of bearings that are disposed in the bearing chambers, and rotatably support the respective shafts; and
seal devices that are disposed in each of the discharge side seal chambers and the intake side seal chambers, and each seal a circumference of a corresponding one of the shafts,
wherein the discharge side seal chambers are positioned on a discharge side of the compression chamber, and the intake side seal chambers are positioned on an intake side of the compression chamber,
the seal devices each include:
a first seal unit that is disposed on a side of the screw chamber in each of the discharge side seal chambers and the intake side seal chambers; and
a second seal unit that is disposed on a side of the bearing unit in each of the discharge side seal chambers and the intake side seal chambers, the second seal unit and the first seal unit defining a separation gas supply gap therebetween,
in the housing, a separation gas supply path through which the separation gas is supplied into the separation gas supply gap, and a pressure balancing path through which an area closer to the screw chamber than the first seal unit in the discharge side seal chamber is in communication with the compression chamber under a pressure higher than an inlet pressure of the target gas sucked into the oil-cooled screw compressor and lower than a discharge pressure of the target gas discharged from the oil-cooled screw compressor, are defined in addition to the tooth surface lubricating fluid flow path and the bearing lubricating fluid flow path, and
a check valve that restricts a flow of a fluid in a direction from the screw chamber to the discharge side seal chamber is disposed in the pressure balancing path.

2. The oil-cooled screw compressor system according to claim 1 , wherein
the housing includes:
a screw casing which defines the screw chamber;
seal casings which are detachably coupled to the screw casing and define the discharge side seal chambers and intake side seal chambers and the pressure balancing path; and
bearing casings which are detachably coupled to the screw casing via the respective seal casings, and define the respective bearing chambers.

3. The oil-cooled screw compressor system according to claim 1 , wherein
the first seal unit includes a first labyrinth seal having a first non-contact seal structure, and
the second seal unit includes a second labyrinth seal having a second non-contact seal structure and a contact seal portion that are arranged in this order from the separation gas supply gap to the bearing chamber.

4. The oil-cooled screw compressor system according to claim 1 , wherein
the first seal unit includes a first labyrinth seal having a first non-contact seal structure,
the second seal unit includes a second labyrinth seal having a second non-contact seal structure, a first lip seal portion having a first contact seal structure, and a second lip seal portion having a second contact seal structure that are arranged in this order from the separation gas supply gap to the bearing chamber,
the first lip seal portion restricts a flow of a fluid in a direction from the screw chamber to the bearing chambers, and
the second lip seal portion restricts a flow of a fluid in a direction from the bearing chambers to the screw chamber.

5. The oil-cooled screw compressor system according to claim 1 further comprising a control system which controls a supply pressure for the separation gas supplied to the oil-cooled screw compressor, wherein
the control system controls the supply pressure for the separation gas in such a manner which the supply pressure for the separation gas supplied to the oil-cooled screw compressor becomes higher than the inlet pressure and lower than the discharge pressure.

6. The oil-cooled screw compressor system according to claim 5 , wherein the control system controls a lubricating fluid supply pressure for the bearing lubricating fluid in such a manner which a return pressure of the bearing lubricating fluid flowing out from the oil-cooled screw compressor becomes equal to or higher than the intake pressure and lower than the supply pressure for the separation gas.

7. The oil-cooled screw compressor system according to claim 6 , wherein
the bearing lubricating fluid supply system includes a storage tank which stores the bearing lubricating fluid under a storage pressure higher than the intake pressure, and
gas of a same type as the separation gas is used as pressurized gas with which a pressure in the storage tank rises up to the storage pressure.

8. The oil-cooled screw compressor system according to claim 5 , wherein
the control system includes
an intake pressure sensor which detects the intake pressure;
a control valve which is able to adjust the supply pressure for the separation gas; and

a control device which operates the control valve in accordance with a detection result of the intake pressure sensor.

9. The oil-cooled screw compressor system according to claim 1 , wherein
the oil-cooled screw compressor further includes a capacity control device, and
the tooth surface lubricating fluid supply system supplies a working fluid to the capacity control device, the working fluid being part of the tooth surface lubricating fluid.

10. An oil-cooled screw compressor comprising:
a housing in which a screw chamber, discharge side seal chambers connected to one end of the screw chamber, intake side sea chambers connected to the other end of the screw chamber, bearing chambers in communication with the screw chamber via either the discharge side seal chambers or the intake side seal chambers, respectively, a tooth surface lubricating fluid flow path through which a tooth surface lubricating fluid is supplied to the screw chamber, and a bearing lubricating fluid flow path through which a bearing lubricating fluid is supplied to the bearing chambers in addition to the tooth surface lubricating fluid flow path, are defined;
male and female screw rotors each including: a screw which is disposed in the screw chamber and forms a compression chamber; and shafts which coaxially extend from both ends of the screw to be disposed in the discharge side se

Assignees

• Endo Yasuaki
• Kaneko Fumihiko
• Yamashita Hironori
• Maekawa Seisakusho Kk

Inventors

• Endo Yasuaki
• Kaneko Fumihiko
• Yamashita Hironori

Classifications

• F04C18/16

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

• F04C29/021

  Control systems for the circulation of the lubricant · CPC title

• F04C29/026

  Lubricant separation · CPC title

• F04C29/12

  Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet · CPC title

• F04C27/009 Primary

  Shaft sealings specially adapted for pumps · CPC title