Oil free screw compressor

Patent metadata

Field	Value
Publication number	US-2016298629-A1
Application number	US-201615186775-A
Country	US
Kind code	A1
Filing date	Jun 20, 2016
Priority date	Jul 3, 2007
Publication date	Oct 13, 2016
Grant date	—

Abstract

Provided is a highly reliable oil free screw compressor including a first sensor for detecting a temperature of lubrication oil, second sensors for detecting temperatures of intake air, and a cooling fan controller having a storage portion storing therein a set temperature of lubrication oil and a set temperature of intake air, and a computing portion for computing a control signal for increasing the speed of the cooling fan if a detected value of a temperature of the lubrication oil, delivered from the first sensor, becomes higher than the set value of lubrication oil stored in the storage portion, and computing a control signal for increasing the speed of the cooling fan if a detected value of a temperature of the intake air, delivered from the second sensor, becomes higher than the set temperature of the intake air, stored in the storage portion.

First claim

1 . An oil free compressor comprising:
a compressor body for compressing intake air, a compressor housing, a compressed air discharge line provided in the compressor housing for discharging compressed air, a lubrication oil pipe line for flowing lubrication oil, an air cooler for cooling the compressed air flowing in the compressed air discharge line, an oil cooler for cooling the lubrication oil flowing in the lubrication oil pipe line, a cooling fan for feeding cooling air into the oil cooler and the air cooler, a cooling fan controller for increasing the rotating speed of the cooling fan if a temperature of the lubrication oil becomes higher than a predetermined temperature, and for increasing the rotating speed of the cooling fan if a temperature of the intake air becomes higher than a predetermined temperature.

2 . The oil free compressor as set forth in claim 1 , wherein
the rotating speed of the cooling fan is controlled by an inverter exclusively used for the cooling fan.

3 . The oil free compressor as set forth in claim 1 , wherein
the rotating speed of the cooling fan is controlled by an inverter used for the compressor.

4 . The oil free compressor as set forth in claim 1 , wherein
the cooling fan controller receives temperatures of the inside of the compressor and temperatures of the outside of the compressor so as to control the rotating speed of the cooling fan.

5 . The oil free compressor as set forth in claim 1 , wherein
the cooling fan controller receives a temperature in a control panel so as to control the rotating speed of the cooling fan.

6 . The oil free compressor as set forth in claim 1 , wherein
a rotor of the compressor body is supported at least on one end by bearings, and the bearings are lubricated by lubricating oil flowing in the lubrication oil pipe line.

7 . The oil free compressor as set forth in claim 1 , wherein
the compressor comprises at least two compressor bodies.

8 . The oil free compressor as set forth in claim 1 , wherein
the compressor comprises at least a first stage compressor body and a second stage compressor body, and the compressed air discharge line provided in the compressor housing comprises a first portion for discharging compressed air from the first stage compressor body and delivering the compressed air to the second stage compressor body and second portion for discharging compressed air from the second stage compressor body and delivering the compressed air outside the compressor housing.

9 . The oil free compressor as set forth in claim 10 , wherein
the air cooler comprises a first cooler for cooling compressed air flowing in the first portion of the compressed air discharge line and a second cooler for cooling compressed air flowing in the second portion of the compressed air discharge line.

10 . The oil free compressor as set forth in claim 1 , further comprising
a first sensor for detecting a temperature of lubrication oil, which is provided in a position for detecting a temperature of lubrication oil in the lubrication oil pipeline downstream of the air cooling cooler for cooling lubrication oil.

11 . The oil free compressor as set forth in claim 1 , further comprising
a second sensor being provided in a position for detecting a temperature of intake air on a suction side of the compressor body, or being provided in a position for detecting a temperature compressed air flowing in the compressed air discharge line.

12 . The oil free compressor as set forth in claim 1 , wherein
the compressed air discharge line discharges compressed air directly from the compressor body, and the compressed air discharged through the compressed air discharge line does not pass through a gear casing or an oil sump of the compressor body.

Assignees

• Hitachi Industry Equipment Systems Co Ltd

Inventors

• Fujimoto Hideki
• Nishimura Hitoshi

Classifications

• F04C2240/30

  Casings or housings · CPC title

• F04C18/16

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

• F04C29/02

  Lubrication (of machines or engines in general F01M); Lubricant separation (separation in general B01D) · CPC title

• F04C2240/81

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

• F04C29/12

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