Multistage compression system

Patent metadata

Field	Value
Publication number	US-11428225-B2
Application number	US-201917277687-A
Country	US
Kind code	B2
Filing date	Sep 25, 2019
Priority date	Sep 28, 2018
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, an oil return pipe that returns the oil discharged by the high-stage compressor to the low-stage compressor, and an oil discharge pipe that discharges the oil in the low-stage compressor. The low-stage compressor includes a compression part that compresses the refrigerant, a motor that drives the compression part, and a container that houses the compression part and the motor. The container forms a high-pressure space storing compressed refrigerant. Inside of the oil return pipe and inside of the oil discharge pipe are connected to the high-pressure space.

First claim

What is claimed is:

1. A multistage compression system using refrigerant and oil, the multistage compression system comprising: a low-stage compressor configured to compress and discharge the refrigerant, a high-stage compressor configured to further compress the refrigerant compressed by the low-stage compressor; an intermediate pressure refrigerant pipe that receives the refrigerant discharged from the low-stage compressor; a suction pipe that delivers the refrigerant to the low-stage compressor; an oil return pipe configured to return oil discharged by the high-stage compressor to the low-stage compressor; and an oil discharge pipe configured to discharge oil in the low-stage compressor, the low-stage compressor including a low-stage compression part configured to compress the refrigerant, a low-stage motor arranged and configured to drive the low-stage compression part, and a low-stage container that houses the low-stage compression part and the low-stage motor, the low-stage container forming a high-pressure space storing compressed refrigerant, the high-stage compressor including a high-stage compression part, a high-stage motor and a high-stage container that are separate from the low-stage compression part, the low-stage motor, and the low-stage container, an inside of the oil return pipe and an inside of the oil discharge pipe being connected to the high-pressure space, and each of the intermediate pressure refrigerant pipe, the suction pipe, the oil return pipe, and the oil discharge pipe beige connected to the low-stage container at a different position, the oil return pipe and the oil discharge pipe being connected to the low-stage container above the low-stage compression part and below the low-stage motor.

2. The multistage compression system according to claim 1 , wherein
a connecting portion of the oil return pipe connected to the low-stage container is as high as a connecting portion of the oil discharge pipe connected to the low-stage container.

3. The multistage compression system according to claim 1 , wherein
in a top view, a connecting portion of the oil discharge pipe connected to the low-stage container is at a position separated by 90° or more in a rotation direction of the low-stage motor from a connecting portion of the oil return pipe connected to the low-stage container.

4. The multistage compression system according to claim 3 , wherein
in a top view, the connecting portion of the oil discharge pipe connected to the low-stage container is at a position separated by 180° or more in the rotation direction of the low-stage motor from the connecting portion of the oil return pipe connected to the low-stage container.

5. The multistage compression system according to claim 1 , wherein
the oil discharge pipe has a diameter equivalent to a diameter of the oil return pipe.

6. The multistage compression system according to claim 1 , wherein
the refrigerant mainly includes carbon dioxide, and
the oil is insoluble in carbon dioxide.

7. The multistage compression system according to claim 1 , further comprising: a refrigerant pipe arranged and configured to introduce refrigerant compressed and discharged from the low-stage compressor to a suction portion of the high-stage compressor; and an accumulator disposed between the refrigerant pipe and the intermediate pressure refrigerant pipe, the oil discharge pipe communicating between the low-stage compressor and the intermediate pressure refrigerant pipe.

8. The multistage compression system according to claim 1 , wherein
a connecting portion of the oil return pipe connected to the low-stage container is higher than a connecting portion of the oil discharge pipe connected to the low-stage container.

9. A multistage compression system using refrigerant and oil, the multistage compression system comprising: a low-stage compressor configured to compress and discharge the refrigerant, a high-stage compressor configured to further compress the refrigerant compressed by the low-stage compressor; an intermediate pressure refrigerant pipe that receives the refrigerant discharged from the low-stage compressor; a suction pipe that delivers the refrigerant to the low-stage compressor; an oil return pipe configured to return oil discharged by the high-stage compressor to the low-stage compressor; and an oil discharge pipe configured to discharge oil in the low-stage compressor, the low-stage compressor including a low-stage compression part configured to compress the refrigerant, a low-stage motor arranged and configured to drive the low-stage compression part, and a low-stage container that houses the low-stage compression part and the low-stage motor, the low-stage container forming a high-pressure space storing compressed refrigerant, the high-stage compressor including a high-stage compression part, a high-stage motor and a high-stage container that are separate from the low-stage compression part, the low-stage motor, and the low-stage container, an inside of the oil return pipe and an inside of the oil discharge pipe being connected to the high-pressure space, and each of the intermediate pressure refrigerant pipe, the suction pipe, the oil return pipe, and the oil discharge pipe beige connected to the low-stage container at a different position, and a connecting portion of the oil return pipe connected to the low-stage container being higher than a connecting portion of the oil discharge pipe connected to the low-stage container.

10. The multistage compression system according to claim 9 , wherein
in a top view, the connecting portion of the oil discharge pipe connected to the low-stage container is at a position separated by 90° or more in a rotation direction of the low-stage motor from the connecting portion of the oil return pipe connected to the low-stage container.

11. A multistage compression system using refrigerant and oil, the multistage compression system comprising: a low-stage compressor configured to compress and discharge the refrigerant, a high-stage compressor configured to further compress the refrigerant compressed by the low-stage compressor; an intermediate pressure refrigerant pipe that receives the refrigerant discharged from the low-stage compressor; a suction pipe that delivers the refrigerant to the low-stage compressor; an oil return pipe configured to return oil discharged by the high-stage compressor to the low-stage compressor; and an oil discharge pipe configured to discharge oil in the low-stage compressor, the low-stage compressor including a low-stage compression part configured to compress the refrigerant, a low-stage motor arranged and configured to drive the low-stage compression part, and a low-stage container that houses the low-stage compression part and the low-stage motor, the low-stage container forming a high-pressure space storing compressed refrigerant, the low-stage compression part including a compression chamber configured such that the refrigerant is introduced into the compression chamber and compressed, a muffler provided with a discharge hale configured to discharge the refrigerant compressed in the compression chamber, the high-stage compressor including a high-stage compression part, a high-stage motor and a high-stage container that are separate from the low-stage compression part, the low-stage motor, and the low-stage container, an inside of the oil return pipe and an inside of the oil discharge pipe being connected to the high-pressure space, and each of the intermediate pressure refrigerant pipe, the suction pipe, the oil return pipe, and the oil discharge pipe beige connected to the low-stage container at a different position, and in a top view, a position of the discharge hole of the muf

Assignees

• Daikin Ind Ltd

Inventors

• Okamoto Daisuke
• Kajiwara Mikio
• Nishide Yohei
• Tomioka Naoto
• Adachi Masaaki
• Ohnishi Yousuke
• Ueno Akitoshi
• HORITA Takuya
• Takegami Masaaki

Classifications

• F04C23/00 Primary

  Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids (F04C25/00 takes precedence) · CPC title

• F04B25/00 Primary

  Multi-stage pumps · CPC title

• F04C18/322

  with vanes hinged to the outer member and reciprocating with respect to the outer member · CPC title

• F04C18/356

  with vanes reciprocating with respect to the outer member · CPC title

• F04B39/16

  Filtration; Moisture separation · CPC title