Compressor having hollow shaft

Patent metadata

Field	Value
Publication number	US-9879690-B2
Application number	US-201414893144-A
Country	US
Kind code	B2
Filing date	Jun 2, 2014
Priority date	Jun 6, 2013
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A shaft of a compressor may include a first shaft section defining a first cavity axially extending therein and a second shaft section defining a second cavity axially extending therein. A plurality of inlet holes may be defined on an outer surface of the first shaft section, and a plurality of outlet holes may be defined on an outer surface of the second shaft section. The plurality of inlet holes may be in fluid communication with the first cavity and the plurality of outlet holes may be in fluid communication with the second cavity. The first cavity and the second cavity may form a passageway fluidly coupling the plurality of inlet holes and the plurality of outlet holes.

First claim

I claim:

1. A compressor, comprising:
an inlet at an input end of the compressor, the inlet configured to receive a working fluid at a first pressure;
an outlet at a discharge end of the compressor, the outlet configured to expel the working fluid having a second pressure greater than the first pressure, the input end and the discharge end being axially separated;
a rotatable shaft extending axially between the input end and the discharge end, the rotatable shaft having respective first and second shaft sections, rigidly coupled to each other along a shaft coupling joint, and defining a common passageway fluidly coupling the inlet and the outlet, wherein one of the first or second shaft sections includes a protrusion and the other of the first or second shaft sections defines a corresponding depression configured to receive or seat the protrusion, the protrusion and the corresponding depression configured to align the respective first and second shaft sections coaxially with each other along the shaft coupling joint;
an impeller mounted about the rotatable shaft between the inlet and the outlet;
a balance piston mounted about the rotatable shaft, axially and radially circumscribing the first and second shaft sections over the shaft coupling joint and the respective protrusion and depression, and disposed immediately following the impeller from the input end; and
a balance piston seal mounted about the balance piston,
wherein the passageway is configured to receive at least a portion of the working fluid flowing across the balance piston seal and to supply the portion of the working fluid to the input end.

2. The compressor of claim 1 , wherein the rotatable shaft defines a plurality of inlet holes and a plurality of outlet holes, such that the plurality of inlet holes are circumferentially disposed about the rotatable shaft at or adjacent the discharge end and the plurality of outlet holes are circumferentially disposed about the rotatable shaft at or adjacent the input end, the plurality of inlet holes and the plurality of outlet holes being in fluid communication with the passageway, the inlet, and the outlet.

3. The compressor of claim 2 , wherein the plurality of inlet holes are defined on one of the respective first shaft or second shaft sections and the plurality of outlet holes are defined on the other of the first or second shaft sections.

4. The compressor of claim 2 , wherein the plurality of inlet holes and the plurality of outlet holes are at a same radial distance from the axis of rotation of the rotatable shaft.

5. The compressor of claim 2 , wherein the plurality of outlet holes are disposed such that the portion of the working fluid exiting the passageway combines with the received working fluid.

6. The compressor of claim 1 , wherein the first shaft section and the second shaft section are coupled along the shaft coupling joint by laser welding, or electron beam welding, or friction welding, or inertia welding.

7. The compressor of claim 6 , wherein the shaft coupling joint is oriented radially inboard of the balance piston and radially outboard of the protrusion, and wherein the protrusion defines a cavity in communication with the shaft coupling joint but isolated from the passageway, the cavity configured to collect debris generated during welding of the first and second shaft sections and prevent the debris from entering the passageway.

8. A shaft of a compressor, comprising:
a first shaft section defining a first cavity axially extending therein and a plurality of inlet holes on an outer surface of the first shaft section, the plurality of inlet holes being in fluid communication with the first cavity;
a second shaft section defining a second cavity axially extending therein and a plurality of outlet holes on an outer surface of the second shaft section, the plurality of outlet holes being in fluid communication with the second cavity, the first cavity and the second cavity forming a passageway fluidly coupling the plurality of inlet holes and the plurality of outlet holes;
the respective first and second shaft sections rigidly coupled to each other along a shaft coupling joint, wherein one of the first or second shaft sections includes a protrusion and the other of the first or second shaft sections defines a corresponding depression configured to receive or seat the protrusion, the protrusion and the corresponding depression configured to align the respective first and second shaft sections coaxially with each other along an axis of rotation of the shaft and along the shaft coupling joint;
a centrifugal compressor impeller mounted about the second shaft section between the inlet holes and the outlet holes, the impeller having a front face for compressing a working fluid when the first and second shaft sections are coupled to and driven by a motor and an opposing back face;
a balance piston axially and radially circumscribing the first and second shaft sections over the shaft coupling joint and the respective protrusion and depression, and disposed axially adjacent the back face of the impeller.

9. The shaft of claim 8 , wherein the first shaft section and the second shaft section are coupled along the shaft coupling joint by laser welding, or electron beam welding, or friction welding, or inertia welding.

10. The shaft of claim 9 , wherein the shaft coupling joint is oriented radially inboard of the balance piston and radially outboard of the protrusion, and wherein the protrusion defines a cavity in communication with the shaft coupling joint but isolated from the passageway, the cavity configured to collect debris generated during welding of the first and second shaft sections and prevent the debris from entering the passageway.

11. The shaft of claim 8 , wherein the passageway has a substantially constant diameter between the plurality of inlet holes and the plurality of outlet holes.

12. The shaft of claim 8 , wherein the plurality of inlet holes and the plurality of outlet holes are at a same radial distance from the axis of rotation of the shaft.

Assignees

• Dresser-Rand Company
• Griffin Daniel J

Inventors

• Griffin Daniel J

Classifications

• F04D29/0516

  balancing pistons · CPC title

• F04D29/181 Primary

  Axial flow rotors (F04D29/185 take precedence) · CPC title

• F04D7/00

  Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts (F04D11/005, F04D29/22 take precedence) · CPC title

• F04D29/054

  Arrangements for joining or assembling shafts · CPC title

• F04D29/053 Primary

  Shafts · CPC title