Screw compressor with improved suction flow

Patent metadata

Field	Value
Publication number	US-12442374-B2
Application number	US-202318843632-A
Country	US
Kind code	B2
Filing date	Mar 3, 2023
Priority date	Mar 15, 2022
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

A suction flow path of a screw compressor includes a male-side flow path that opens in an axial direction with respect to working chambers in a suction process on the male rotor side and extends from a starting end positioned on one side of a virtual plane to a first termination end positioned on the other side; and a female-side flow path on the female rotor side that extends from the starting end to a second termination end positioned on the other side of the virtual plane. The male-side or the female-side first flow path wall is configured such that at least a partial area in a range from the starting end to the first or the second termination end is closer to a male-side or female-side rotor lobe section from the starting end side toward the first or second termination end side.

First claim

The invention claimed is:

1. A screw compressor comprising:
a male rotor that has a first rotor lobe section and is rotatable around a first axis line;
a female rotor that has a second rotor lobe section and is rotatable around a second axis line;
a casing that has a housing chamber for housing the first rotor lobe section and the second rotor lobe section in a state of being meshed with each other and forming a plurality of working chambers; and
a suction flow path disposed in the casing configured to introduce working fluid from an outside of the casing to working chambers in a suction process, the suction flow path including:
a male-side flow path that opens in an axial direction of the male rotor with respect to working chambers on the male rotor side among the working chambers in the suction process and that extends from a first starting end to a first termination end, the first starting end being positioned on one side with respect to a virtual plane passing through the first axis line and the second axis line and being on an inflow side of the working fluid, the first termination end being positioned on other side with respect to the virtual plane, and
a female-side flow path that opens in an axial direction of the female rotor with respect to working chambers on the female rotor side among the working chambers in the suction process and that extends from a second starting end to a second termination end, the second starting end being positioned on the one side with respect to the virtual plane and being on the inflow side of the working fluid, the second termination end being positioned on the other side with respect to the virtual plane,

wherein the male-side flow path includes a male-side first flow path wall that faces a suction-side end face side of the first rotor lobe section and extends from the first starting end to the first termination end,
wherein the female-side flow path includes a female-side first flow path wall that faces a suction-side end face side of the second rotor lobe section and extends from the second starting end to the second termination end,
wherein the male-side first flow path wall is configured such that at least a partial area in a range from the first starting end to the first termination end is closer to the first rotor lobe section from the first starting end side toward the first termination end side, or the female-side first flow path wall is configured such that at least a partial area in a range from the second starting end to the second termination end is closer to the second rotor lobe section from the second starting end side toward the second termination end side,
wherein the male-side first flow path wall has an inclined face that is gradually closer to the first rotor lobe section from the first starting end side toward the first termination end side, or the female-side first flow path wall has an inclined face that is gradually closer to the second rotor lobe section from the second starting end side toward the second termination end side, and
wherein the male-side first flow path wall is configured such that the inclined face extends from a position on the one side with respect to the virtual plane to a certain first position before reaching the first termination end, and such that an area from the first position to the first termination end is a flat face equally distant from the first rotor lobe section, or the female-side first flow path wall is configured such that the inclined face extends from a position on the one side with respect to the virtual plane to a certain second position before reaching the second termination end, and such that an area from the second position to the second termination end is equally distant from the second rotor lobe section.

2. The screw compressor according to claim 1 , wherein
the inclined face of the male-side first flow path wall extends from a position on the one side with respect to the virtual plane to the first termination end, or
the inclined face of the female-side first flow path wall extends from a position on the one side with respect to the virtual plane to the second termination end.

3. The screw compressor according to claim 1 , wherein
a second flow path wall that defines the male-side flow path and is positioned outward in a radial direction of the male rotor is configured to, at least partially, be flush with a wall face of the housing chamber when viewed from the axial direction of the male rotor, or
a second flow path wall that defines the female-side flow path and is positioned outward in a radial direction of the female rotor is configured to, at least partially, be flush with the wall face of the housing chamber when viewed from the axial direction of the female rotor.

4. The screw compressor according to claim 3 , wherein
the second flow path wall of the male-side flow path is configured to be gradually closer from an outer side in the radial direction of the male rotor to and then be flush with the wall face of the housing chamber from a position of the virtual plane toward the first termination end, when viewed from the axial direction of the male rotor, or
the second flow path wall of the female-side flow path is configured to be gradually closer from an outer side in the radial direction of the female rotor to and then be flush with the wall face of the housing chamber from the position of the virtual plane toward the second termination end, when viewed from the axial direction of the female rotor.

5. The screw compressor according to claim 3 , wherein
the second flow path wall of the male-side flow path is configured to be flush with the wall face of the housing chamber in a range from a position of the virtual plane to the first termination end when viewed from the axial direction of the male rotor, or
the second flow path wall of the female-side flow path is configured to be flush with the wall face of the housing chamber in a range from the position of the virtual plane to the second termination end when viewed from the axial direction of the female rotor.

6. The screw compressor according to claim 1 , wherein
the male-side flow path is configured such that a direction from the first starting end to the first termination end corresponds to a rotation direction of the male rotor, and
the female-side flow path is configured such that a direction from the second starting end to the second termination end corresponds to a rotation direction of the female rotor.

7. The screw compressor according to claim 1 , wherein
the casing includes:
a first casing configured to house the first rotor lobe section and the second rotor lobe section, and
a second casing having the male-side flow path and the female-side flow path, the second casing being a member different from the first casing and being attached to the first casing.

8. The screw compressor according to claim 1 , wherein
the suction flow path is configured to open only in the axial directions of the male rotor and the female rotor with respect to the working chambers in the suction process.

Assignees

• Hitachi Industry Equipment Systems Co Ltd

Inventors

• Tsuchiya Takeshi
• Chiba Kotaro
• Yabe Toshiaki
• Sakai Kohei
• Taniyama Yuki
• NIKAIDO Sho
• Sano Shotaro

Classifications

• F04C2250/101

  of the inlet · CPC title

• F04C2240/30

  Casings or housings · CPC title

• F04C29/12

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

• F04C18/086

  Carter · CPC title

• F04C18/16 Primary

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