Screw rotor with high lobe count

Patent metadata

Field	Value
Publication number	US-10436196-B2
Application number	US-201515315551-A
Country	US
Kind code	B2
Filing date	Jun 1, 2015
Priority date	Jun 2, 2014
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

A compressor ( 22 ) comprises a housing ( 50 ) having a first port ( 26 ) and a second port ( 28 ). A male rotor ( 52 ) has a working portion ( 64 ) having a plurality of lobes ( 110 ) of a count (N M ) and at least a first shaft portion ( 62 ) protruding beyond a first end ( 68 ) of the male rotor working portion and mounted for rotation about a first axis ( 500 ). A female rotor ( 54 ) has a working portion ( 66 ) having a plurality of lobes ( 112 ) of a count (N F ) and mounted for rotation about a second axis ( 502 ) so as to be enmeshed with the male rotor working portion. An electric motor ( 56 ) is within the housing and has a stator ( 58 ) and a rotor ( 60 ) mounted to the first shaft portion. The compressor has no additional compressor rotors. The lobe count of the male rotor is less than the lobe count of the female rotor. A combined lobe count (N M +N F ) is at least fifteen.

First claim

What is claimed is:

1. A compressor ( 22 ) comprising:
a housing ( 50 ) having a first port ( 26 ) and a second port ( 28 );
a male rotor ( 52 ) having:
a working portion ( 64 ) having a plurality of lobes ( 110 ) of a count (N M ); and
at least a first shaft portion ( 62 ) protruding beyond a first end ( 68 ) of the male rotor working portion and mounted for rotation about a first axis ( 500 );

a female rotor ( 54 ) having:
a working portion ( 66 ) having a plurality of lobes ( 112 ) of a count (N F ) and mounted for rotation about a second axis ( 502 ) so as to be enmeshed with the male rotor working portion; and

an electric motor ( 56 ) within the housing and having:
a stator ( 58 ); and
a motor rotor ( 60 ) mounted to the first shaft portion,

wherein:
one or both of:
a tip-to-root ratio of the lobes of the female rotor is no more than 1.50:1; and
a tip-to-root ratio of the lobes of the male rotor is no more than 1.42:1;

the lobe count of the male rotor is less than the lobe count of the female rotor; and
a combined lobe count (N M +N F ) is at least fifteen.

2. The compressor of claim 1 wherein:
the compressor has no additional compressor rotors.

3. The compressor of claim 1 wherein:
the combined lobe count (N M +N F ) is fifteen to twenty-one.

4. The compressor of claim 1 wherein:
the lobe count (N M ) of the male rotor and the lobe count (N F ) of the female rotor are no more than one different from each other.

5. The compressor of claim 1 wherein:
the lobe count (N M ) of the male rotor is one less than the lobe count (N F ) of the female rotor.

6. The compressor of claim 1 wherein one of:
the lobe count of the male rotor is seven and the lobe count of the female rotor is eight;
the lobe count of the male rotor is eight and the lobe count of the female rotor is nine;
the lobe count of the male rotor is nine and the lobe count of the female rotor is ten; and
the lobe count of the male rotor is ten and the lobe count of the female rotor is eleven.

7. The compressor of claim 1 wherein:
the tip-to-root ratio of the lobes of the female rotor is no more than 1.50:1; and
the tip-to-root ratio of the lobes of the male rotor is no more than 1.42:1.

8. The compressor of claim 7 wherein one or both of:
the tip-to-root ratio of the lobes of the female rotor is 1.30:1 to 1.50:1; and
the tip-to-root ratio of the lobes of the male rotor is 1.36:1 to 1.42:1.

9. The compressor of claim 7 wherein:
the tip-to-root ratio of the lobes of the female rotor is 1.30:1 to 1.50:1; and
the tip-to-root ratio of the lobes of the male rotor is 1.36:1 to 1.42:1.

10. The compressor of claim 7 wherein:
the lobe count of the male rotor is seven and the lobe count of the female rotor is eight;
the tip-to-root ratio of the lobes of the female rotor is 1.49:1 to 1.50:1; and
the tip-to-root ratio of the lobes of the male rotor is 1.41:1 to 1.42:1.

11. The compressor of claim 1 wherein:
a full-load volume index is 1.7-4.0.

12. The compressor of claim 1 wherein:
the first shaft portion ( 62 ) is cantilevered from a bearing ( 90 ) between the first shaft portion and the male rotor working portion ( 64 ).

13. A method for using the compressor of claim 1 , the method comprising:
running the compressor at a speed of at least 90 Hz.

14. The method of claim 13 wherein:
the running of the compressor compresses refrigerant;
the compressed refrigerant is passed to a heat rejection heat exchanger to cool the refrigerant;
the cooled refrigerant is passed to an expansion device to expand and further cool the cooled refrigerant;
the expanded and further cooled refrigerant is passed to a heat absorption heat exchanger to absorb heat and warm the expanded and further cooled refrigerant; and
the warmed refrigerant is passed back to the compressor.

15. The method of claim 13 wherein:
the running of the compressor comprises operating at volume index of 1.7-4.0.

16. A vapor compression system ( 20 ) comprising:
the compressor ( 22 ) of claim 1 ;
a heat rejection heat exchanger ( 30 );
an expansion device ( 32 );
a heat absorption heat exchanger ( 34 ); and
a refrigerant flowpath ( 24 ) passing sequentially through the compressor, the heat rejection heat exchanger, the expansion device and the heat absorption heat exchanger and returning to the compressor.

Assignees

• Carrier Corp

Inventors

• Vaidya Amit

Classifications

• F04C23/008 Primary

  Hermetic pumps · CPC title

• F04C18/084

  Toothed wheels · CPC title

• F04C18/16 Primary

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