Multi-stage horizontal centrifugal pump for conveying a fluid and a method for repairing the same

Patent metadata

Field	Value
Publication number	US-10724526-B2
Application number	US-201615381351-A
Country	US
Kind code	B2
Filing date	Dec 16, 2016
Priority date	Dec 30, 2015
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

A multi-stage horizontal centrifugal pump for conveying a fluid has a rotor including a rotatably arranged shaft and a plurality of impellers for conveying the fluid and a stator. All the impellers are arranged in a rotatably fixed manner on the shaft. The stator includes a plurality of stage casings, which are arranged consecutively one after another with respect to an axial direction determined by a central axis. The stator encompasses the rotor, and each stage casing is designed and arranged centrically with respect to the central axis. A plurality of wear rings is disposed between the rotor and the stator, each of which is fixed with respect to the stator, and surrounds the rotor with a clearance. At least one of the wear rings is designed eccentrically.

First claim

The invention claimed is:

1. A multiple-stage horizontal centrifugal pump for conveying a fluid, comprising:
a rotor comprising a rotatably arranged shaft and a plurality of impellers for conveying the fluid, each impeller of the plurality of impellers being arranged in a rotatably fixed manner on the shaft;
a stator comprising a plurality of stage casings arranged consecutively one after another with respect to an axial direction determined by a central axis, the stator encompassing the rotor, and each stage casing of the plurality of stage casings being configured and arranged centrically with respect to the central axis;
a plurality of wear rings disposed between the rotor and the stator, each wear ring of the plurality of wear rings being fixed with respect to the stator, and surrounding the rotor with a clearance, at least one wear ring of the plurality of wear rings is designed eccentrically and unitarily; and wherein each stage casing of the plurality of stage casings is separate from each other stage casing of the plurality of stage casings.

2. The multiple-stage horizontal centrifugal pump according to claim 1 , wherein at least two wear rings of the plurality of wear rings is designed eccentrically.

3. The multiple-stage horizontal centrifugal pump according to claim 1 , wherein the least two wear rings of the plurality of wear rings have an eccentricity which increases towards a center of the pump.

4. The multiple-stage horizontal centrifugal pump according to claim 3 , wherein the eccentricity of the least two wear rings is adjusted to a sag line of the shaft.

5. The multiple-stage horizontal centrifugal pump according to claim 3 , wherein the eccentricity of the at least two wear rings is such that during a standstill of the shaft none of the wear rings is in contact with the shaft or the impellers.

6. The multiple-stage horizontal centrifugal pump according to claim 3 , wherein the eccentricity of the at least two wear rings is such that the sag line of the shaft extends essentially centered with respect to the plurality of wear rings at a nominal speed of the pump.

7. The multiple-stage horizontal centrifugal pump according to claim 1 , further comprising a plurality of pump stages arranged consecutively one after another with respect to the axial direction, each pump stage comprising an impeller of the plurality of impellers for pumping the fluid, including a front cover plate, a stage casing of the plurality of stage casings and a partition wall for conducting the fluid to the adjacent pump stage, the partition wall being stationary with respect to the stage casing, the stage casing for each pump stage having a stationary impeller opening to receive the front cover plate of a respective impeller, each stationary impeller opening being radially inwardly confined by a first wear ring of the plurality of wear rings, which surrounds the front cover plate of the impeller with the clearance, and each stationary partition wall being radially inwardly confined by a second wear ring of the plurality of wear rings, which surrounds the shaft with another clearance.

8. The multiple-stage horizontal centrifugal pump according to claim 1 , wherein the at least one wear ring of the plurality of wear rings comprises a positioning device configured to position the at least one wear ring at a predefined angular orientation in a stage casing or a partition wall.

9. The multiple-stage horizontal centrifugal pump according to claim 8 , wherein the positioning device is disposed on the at least one wear ring at a maximum width of the at least one wear ring in a radial direction.

10. The multiple-stage horizontal centrifugal pump according to claim 1 , wherein each stage casing of the plurality of stage casings is arranged in a barrel casing.

11. The multiple-stage horizontal centrifugal pump according to claim 1 , further comprising an inlet, an outlet, and an intermediate outlet configured to convey the fluid, the intermediate outlet being designed and arranged such that at least a part of the fluid is capable of being discharged at an intermediate pressure through the intermediate outlet, the intermediate pressure being greater than a pressure of the fluid at the inlet ( 4 ) of the pump and less than the pressure of the fluid at the outlet of the pump.

12. A method for repairing or overhauling a multi-stage horizontal centrifugal pump for conveying a fluid having a rotor comprising a rotatably arranged shaft and a plurality of impellers for conveying the fluid, each impeller of the plurality of impellers arranged in a rotatably fixed manner on the shaft, and having a stator comprising a plurality of stage casings arranged consecutively one after another with respect to an axial direction determined by a central axis, the stator encompassing the rotor, and each stage casing of the plurality of stage casings designed and arranged centrically with respect to the central axis, and a plurality of wear rings disposed between the rotor and the stator, each wear ring of the plurality of wear rings fixed with respect to the stator, and surrounding the rotor with a clearance, the method comprising;
replacing at least one wear ring of the plurality of wear rings with an eccentrically and unitarily designed wear ring; and wherein each stage casing of the plurality of stage casings is separate from each other stage casing of the plurality of stage casings.

13. The method according to claim 12 , further comprising adjusting the eccentricity of the at least one wear ring of the plurality of wear rings to a sag line of the shaft.

14. The method according to claim 12 , further comprising measuring the eccentricity of the at least one wear ring of the plurality of wear rings so that during standstill of the shaft none of the plurality of wear rings contacts the shaft.

15. The method according to claim 12 , further comprising measuring the eccentricity of the at least one wear ring of the plurality of wear rings so that the sag line of the shaft extends essentially centered with respect to each wear ring of the plurality of wear rings at a nominal speed of the pump.

Assignees

• Sulzer Management Ag

Inventors

• Lagas Nicolas

Classifications

• F04D17/14

  with means for changing the flow-path through the stages, e.g. series-parallel, e.g. side-loads, (surge control F04D27/02) · CPC title

• F04D15/0272

  the condition being wear or a position · CPC title

• F04D15/0072

  Installation or systems with two or more pumps, wherein the flow path through the stages can be changed, e.g. series-parallel · CPC title

• F04D5/003

  of multistage type · CPC title

• F04D1/10 Primary

  with means for changing the flow-path through the stages, e.g. series-parallel, e.g. side loads · CPC title