Two-stage centrifugal compressor

• US 10,968,919 B2
• Filed: 11/09/2017
• Issued: 04/06/2021
• Est. Priority Date: 12/14/2016
• Status: Active Grant

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Sishtla, Vishnu M.
• Primary Examiner(s): Truong, Thomas
• Application Number:
  US16/461,985
• Publication Number:
  US 20190323515A1
• Time in Patent Office: 1,244 Days
• CPC Class Codes: F04D 17/12 Multi-stage pumps
• CPC Class Codes: F04D 29/051 Axial thrust balancing
• CPC Class Codes: F04D 29/052 Axially shiftable rotors F04D29/051 takes precedence ; control by creating a by-pass F04D27/0246
• CPC Class Codes: F04D 29/058 magnetic; electromagnetic
• CPC Class Codes: F04D 29/162 of a centrifugal flow wheel

Abstract

A compressor (22) comprises: a housing (50); a shaft (70); a plurality of bearings (66, 67, 68, 74, 76) mounting the shaft to the housing for relative rotation about an axis (500); and a motor (52). The motor has: a rotor (64) mounted on the shaft; and a stator (62). A first impeller (54A) is mounted the shaft to a first side of the motor. A second impeller (54B) is mounted the shaft to a second side of the motor. The first impeller is an open impeller and the second impeller is a shrouded impeller.

Claims

1. A compressor (22) comprising:

a housing (50);

a shaft (70);

a plurality of bearings (66, 67, 68, 74, 76) mounting the shaft to the housing for relative rotation about an axis (500);

a motor (52), having;

a rotor (64) mounted on the shaft; and

a stator (62);

a first impeller (54A) mounted the shaft to a first side of the motor; and

a second impeller (54B) mounted the shaft to a second side of the motor,

wherein;

the first impeller is an open impeller;

the second impeller is a shrouded impeller; and

the plurality of bearings comprises a magnetic thrust bearing (68).

2. The compressor of claim 1 wherein:

the first impeller has an axial inlet and a radial outlet; and

the second impeller has an axial inlet and a radial outlet.

3. The compressor of claim 2 wherein:

the first impeller inlet and the second impeller inlet face outward from the motor in opposite axial directions.

4. The compressor of claim 1 further comprising:

a radial balance piston seal (140) sealing the first impeller.

5. The compressor of claim 1 further comprising:

an axial balance piston seal (160) sealing the second impeller.

6. The compressor of claim 1 further comprising:

a radial seal (170) sealing the second impeller'"'"'s shroud.

7. The compressor of claim 1 wherein:

the first impeller is of a stage; and

the second impeller is of another stage in series with the stage.

8. The compressor of claim 1 wherein:

the first impeller is a lower pressure impeller and the second impeller is a higher pressure impeller so that a flowpath from a compressor inlet to a compressor outlet proceeds sequentially through the first impeller and then the second impeller.

9. The compressor of claim 8 wherein:

the first impeller has a greater blade height than does the second impeller.

10. The compressor of claim 1 wherein:

the plurality of bearings further comprises a first magnetic radial bearing (66) and a second magnetic radial bearing (67).

11. The compressor of claim 1 further comprising:

a controller configured to control the magnetic thrust bearing to vary clearance of the first impeller.

12. The compressor of claim 1 wherein:

the first impeller has a greater blade height than does the second impeller.

13. A method for using the compressor of claim 1, the method comprising:

controlling the magnetic thrust bearing to vary clearance of the first impeller.

14. The method of claim 13 wherein:

the varying includes reducing the clearance of the first impeller to increase a sealing engagement of a seal of the second impeller.