Centrifugal pump

Patent metadata

Field	Value
Publication number	US-11603844-B2
Application number	US-201917415351-A
Country	US
Kind code	B2
Filing date	Dec 19, 2019
Priority date	Dec 21, 2018
Publication date	Mar 14, 2023
Grant date	Mar 14, 2023

Abstract

A centrifugal pump (1) including: a pump housing (3) enclosing a pump chamber (13), the pump chamber (13) including a suction inlet (15) and a pressure outlet (17); an impeller (19) rotatably arranged within the pump chamber (13) for being driven to rotate about a rotor axis (R), the suction inlet (15) being located coaxial with the rotor axis (R); and at least one stationary scraper (39). The impeller (19) includes an impeller base (31) and at least one or more impeller vanes (33) extending from the impeller base (31) towards the suction inlet (15). Each of the impeller vanes (33) includes a radially innermost vane path (45) describing during impeller rotation a central volume (41) that is wider towards the suction inlet (15) than towards the impeller base (31) and configured to receive the at least one scraper (39) projecting from the suction inlet (15) into the central volume (41).

First claim

The invention claimed is:

1. A centrifugal pump comprising:
a pump housing enclosing a pump chamber, wherein the pump chamber comprises a suction inlet and a pressure outlet;
an impeller rotatably arranged within the pump chamber for being driven to rotate about a rotor axis, wherein the suction inlet is located coaxial with the rotor axis; and
at least one stationary scraper wherein the impeller comprises an impeller base and one or more vanes extending from the impeller base towards the suction inlet, wherein each of the impeller vanes comprises a radially innermost vane path describing during impeller rotation a central volume that is wider towards the suction inlet than towards the impeller base and that is configured to receive the at least one stationary scraper projecting from the suction inlet into the central volume, wherein each of the impeller vanes comprises a leading edge extending from a leading edge base point at the impeller base to a leading edge ridge point at a vane ridge surface, wherein the leading edge is backwardly swept from the leading edge base point to the leading edge ridge point, wherein the leading edge has a distance in radial and/or circumferential direction from the radially innermost vane path, each of the one or more vanes has a concave surface directed radially inward toward the rotor axis.

2. The centrifugal pump according to claim 1 , wherein the at least one stationary scraper comprises a radially outward scraper surface acting as a first scraping path and positioned to form a scrape gap to the radially innermost vane path acting as a second scraping path during impeller rotation.

3. The centrifugal pump according to claim 2 , wherein the scrape gap is in the range of 0.1 to 5 mm.

4. The centrifugal pump according to claim 2 , wherein the scrape gap is constant or varies along the radially innermost vane path.

5. The centrifugal pump according to claim 1 , wherein the at least one stationary scraper is mounted to or an integral part of the suction inlet at a scraper connection angle in the range of 110° to 170°.

6. The centrifugal pump according to claim 1 , wherein the at least one stationary scraper comprises a guiding surface facing backward in a circumferential direction of impeller rotation, and wherein the guiding surface is inclined against the circumferential direction of impeller rotation from the suction inlet towards the impeller base.

7. The centrifugal pump according to claim 1 , wherein the at least one stationary scraper extends straight in an axial direction.

8. The centrifugal pump according to claim 1 , wherein the vane ridge surface of each impeller vane faces towards a cover surface of the suction inlet, wherein the impeller is positioned relative to the cover surface to form a cover gap between the vane ridge surface and the cover surface.

9. The centrifugal pump according to claim 8 , wherein the cover gap is in the range of 0.1 to 1 mm.

10. The centrifugal pump according to claim 8 , wherein the cover surface comprises at least one groove extending from a groove inlet port at an inner radius of the cover surface to a groove outlet port at an outer radius of the cover surface.

11. The centrifugal pump according to claim 10 , wherein the groove inlet port extends between a first angular end and a second angular end, wherein the first angular end and the second angular end have an angular distance of less than 90° to each other, wherein the second angular end is located behind the first angular end in a circumferential direction of impeller rotation, wherein the at least one stationary scraper is located at the second angular end.

12. The centrifugal pump according to claim 1 , wherein the leading edge is swept backwardly by a leading edge sweep angle of at least 20° at the leading edge ridge point.

13. The centrifugal pump according to claim 12 , wherein the leading edge sweep angle is larger at the leading edge base point than at the leading edge ridge point, wherein the leading edge sweep angle is least 20° between the leading edge base point and the leading edge ridge point.

14. The centrifugal pump according to claim 1 , wherein the distance in at least one of the radial direction and the circumferential direction between the leading edge and the radially innermost vane path increases towards the impeller base.

15. The centrifugal pump according to claim 1 , wherein each of the impeller vanes is radially outwardly tilted from the impeller base to the vane ridge surface by a tilt angle of up to 60°.

16. The centrifugal pump according to claim 1 , wherein the radially innermost vane path comprises a first section having a convex shape and a second section having a concave shape.

17. The centrifugal pump according to claim 1 , wherein a height in an axial direction of the at least one stationary scraper is at least 50% of a depth in an axial direction of the central volume.

18. A centrifugal pump comprising:
a pump housing enclosing a pump chamber, wherein the pump chamber comprises a suction inlet and a pressure outlet;
an impeller rotatably arranged within the pump chamber for being driven to rotate about a rotor axis, wherein the suction inlet is located coaxial with the rotor axis; and
at least one stationary scraper wherein the impeller comprises an impeller base and one or more vanes extending from the impeller base towards the suction inlet, wherein each of the impeller vanes comprises a radially innermost vane path describing during impeller rotation a central volume that is wider towards the suction inlet than towards the impeller base and that is configured to receive the at least one stationary scraper projecting from the suction inlet into the central volume, the radially innermost vane path comprises a first section having a convex shape and a second section having a concave shape, each of the one or more vanes has a convex surface being directed radially outward away from the rotor axis.

Assignees

• Grundfos Holding As

Inventors

• Csányi Róbert

Classifications

• F05D2240/303

  related to the leading edge of a rotor blade · CPC title

• F04D29/242

  Geometry, shape · CPC title

• F04D29/2294

  for protection, e.g. against abrasion · CPC title

• F04D29/42

  for radial or helico-centrifugal pumps · CPC title

• F04D29/4293 Primary

  Details of fluid inlet or outlet · CPC title