Coupling for directly driven compressor

Patent metadata

Field	Value
Publication number	US-9371835-B2
Application number	US-201313946371-A
Country	US
Kind code	B2
Filing date	Jul 19, 2013
Priority date	Jul 19, 2013
Publication date	Jun 21, 2016
Grant date	Jun 21, 2016

Abstract

A coupling to attach an impeller of a compressor to a shaft of an electric motor. The coupling has a coupling body that is attached at a first of the ends thereof to the impeller and at the opposite second end, to the motor shaft. The coupling body has a deformable section between the first and second ends of the coupling body. The deformable section is configured such that under an unbalanced loading exerted against the coupling body upon a failure of the impeller, the deformable section will permanently deform without the ultimate strength of a material forming the coupling body being exceeded and prior to a permanent deformation of the shaft. In such manner, the electric motor is protected from damage upon a failure of the impeller.

First claim

We claim:

1. A coupling to attach an impeller of a compressor to a shaft of an electric motor, said coupling comprising:
a coupling body having opposite first and second ends;
means for attaching the coupling body at the first of the ends to the impeller; and
means for attaching the coupling body at the second of the ends to the shaft;
wherein the coupling body has a deformable section between the first and second ends configured such that the deformable section will permanently deform under unbalanced loading exerted against the coupling body upon a failure of the impeller without the ultimate strength of a material forming the coupling body being exceeded and prior to a permanent deformation of the shaft;
wherein the coupling body has an axial bore having a portion sized such that the coupling body has a reduced wall thickness at one location along the length of the coupling body as compared to the wall thickness of a remainder of the coupling body to form the deformable section.

2. The coupling body of claim 1 , wherein:
the axial bore extends from the first to the second of the ends of the coupling body;
the portion of the axial bore is a wider portion thereof that inwardly extends from the second of the ends toward the first of the ends and a narrower portion of the axial bore extends from the wider portion to the first of the ends of the coupling;
the means for attaching the coupling body to the shaft is an annular flange-like section of the coupling body surrounding the wider portion of the axial bore and a set of preloaded screws connecting the annular flange-like section to the shaft at an end thereof; and
the means for attaching the coupling body to the impeller is a preloaded stud retained in the narrower portion of the axial bore by means of a threaded type connection and a tooth-like engagement between the first of the ends of the coupling body and the impeller.

3. The coupling body of claim 2 , wherein:
the end of the shaft has a cylindrical, inwardly extending recess; and
the coupling body has an annular projection extending from the annular flange-like portion sized to seat within the cylindrical, inwardly extending recess located at the end of the shaft to center the coupling body with respect to the shaft.

4. The coupling body of claim 2 , wherein the coupling body has a pair of spaced labyrinth seal elements located on exterior portions of the annular flange-like section and the first of the ends of the coupling body configured to engage complimentary labyrinth seal elements situated on a shaft seal within a housing of the electric motor adjacent to the impeller.

5. The coupling body of claim 3 , wherein the coupling body has a pair of spaced labyrinth seal elements located on exterior portions of the annular flange-like section and the first of the ends of the coupling body configured to engage complimentary labyrinth seal elements situated on a shaft seal within a housing of the electric motor adjacent to the impeller.

6. A compression system comprising:
at least one compressor having an impeller;
an electric motor having a motor shaft coupled to the impeller and configured for driving the impeller of the compressor; and
a coupling body having a first end attached to the impeller and a second end attached to the motor shaft;
wherein the coupling body has a deformable section between the first end and the second end configured such that the deformable section will permanently deform under unbalanced loading exerted against the coupling body upon a failure of the impeller without the ultimate strength of a material forming the coupling body being exceeded and prior to a permanent deformation of the motor shaft;
wherein the coupling body has an axial bore having a portion sized such that the coupling body has a reduced wall thickness at one location along the length of the coupling body as compared to the wall thickness of a remainder of the coupling body to form the deformable section.

7. The compression system of claim 6 wherein the at least one compressor further comprises a first compressor having a first impeller coupled to one end of the motor shaft and a second compressor having a second impeller coupled to the other end of the motor shaft.

8. The compression system of claim 6 wherein the coupling body further comprises:
an annular flange-like section surrounding the portion of the axial bore;
a set of preloaded screws connecting the annular flange-like section to the motor shaft at an end thereof; and
a preloaded stud retained in the axial bore by a threaded type connection and a tooth-like engagement between the first end of the coupling body and the impeller.

9. The compression system of claim 8 wherein:
the axial bore of the coupling body extends from the first end of the coupling body to the second end of the coupling body;
the portion of the axial bore further comprises a wider portion that inwardly extends from the second end toward the first end and a narrower portion that extends from the wider portion to the first end of the coupling body;
wherein the annular flange-like section of the coupling body surrounds the wider portion of the axial bore and the preloaded stud is retained in the narrower portion of the axial bore.

10. The compression system of claim 9 , wherein:
the end of the motor shaft has a cylindrical, inwardly extending recess; and
the coupling body has an annular projection extending from the annular flange-like portion sized to seat within the cylindrical, inwardly extending recess located at the end of the motor shaft to center the coupling body with respect to the motor shaft.

11. The compression system of claim 9 , wherein the coupling body has a pair of spaced labyrinth seal elements located on exterior portions of the annular flange-like section and the first of the ends of the coupling body configured to engage complimentary labyrinth seal elements situated on a shaft seal within a housing of the electric motor adjacent to the impeller.

Assignees

• Stanko Michael J
• Schwarz Carl L
• Owens William J
• Praxair Technology Inc

Inventors

• Stanko Michael J
• Schwarz Carl L
• Owens William J

Classifications

• F01D5/025 Primary

  Fixing blade carrying members on shafts (attachment of a member on a shaft in general F16D1/06; for non-positive displacement pumps F04D29/00) · CPC title

• F16D1/076

  by clamping together two faces perpendicular to the axis of rotation, e.g. with bolted flanges · CPC title

• F04D29/266

  mounting compressor rotors on shafts · CPC title

• F04D25/022

  comprising a yielding coupling, e.g. hydraulic (a magnetic coupling F04D25/026) · CPC title

• F04D29/102

  especially adapted for elastic fluid pumps · CPC title