Rotary pump with axially displaceable, closeable rotor

Patent metadata

Field	Value
Publication number	US-10539142-B2
Application number	US-201414392246-A
Country	US
Kind code	B2
Filing date	Jun 25, 2014
Priority date	Jun 27, 2013
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A centrifugal pump assembly has an electric drive motor (2) and at least one impeller (10; 10′), which is movable in an axial direction (X) between at least two functional positions. In one functional position a flow path through the impeller (10; 10′) is essentially closed and in another functional position the flow path through the impeller (10; 10′) is opened. The impeller (10; 10′) in a first functional position is held by a magnetic force (FM) or a spring force and in a second functional position is held by a hydraulic force (FH) produced by a delivered fluid. An impeller is provided for the centrifugal pump assembly.

First claim

The invention claimed is:

1. A centrifugal pump assembly comprising:
an electric drive motor;
at least one impeller movable in an axial direction between at least two functional positions, wherein in one functional position a flow path through the impeller is essentially closed and in another functional position the flow path through the impeller is opened, wherein the impeller in a first functional position is held by a permanent magnetic force resulting from an axial offset of the permanent magnet rotor relative to the stator of the drive motor and the at least one impeller is held in a second functional position by a hydraulic force produced by a delivered fluid, wherein the hydraulic force is greater than the permanent magnetic force holding the at least one impeller in the first functional position and the hydraulic force is increased if the drive motor is switched on and the hydraulic force decreases if the drive motor is switched off.

2. A centrifugal pump assembly according to claim 1 , wherein the permanent magnetic force acts between a permanent magnet rotor connected to the impeller, and the surrounding stator of the electric drive motor.

3. A centrifugal pump assembly according to claim 1 , wherein the flow path through the impeller is closed in the first functional position.

4. A centrifugal pump assembly according to claim 1 , wherein the flow path through the impeller is closed in the second functional position.

5. A centrifugal pump assembly according to claim 1 , further comprising a closure element, wherein in one of the functional positions the flow path through the impeller is closed, and said one of the functional positions the closure element closes an exit opening or an entry opening of the impeller at least for the larger part.

6. A centrifugal pump assembly according to claim 5 , wherein the closure element in that functional position, in which the flow path through the impeller is closed, closes the entry opening or the exit opening for the larger part, but closes it only to the extent that a pressure build-up on the exit side of the impeller is possible on starting the impeller.

7. A centrifugal pump according to claim 5 , wherein the impeller is movable relative to the closure element between the first and the second functional position.

8. A centrifugal pump assembly according to claim 5 , wherein the impeller comprises an axial-side or radial-side entry opening and the closure element covers the entry opening in one functional position.

9. A centrifugal pump assembly according claim 5 , wherein the impeller comprises a radial-side exit opening, and the closure element covers the exit opening in one functional position.

10. A centrifugal pump assembly according to claim 9 , wherein the closure element is designed as an annular wall which peripherally surrounds the exit opening in one functional position.

11. A centrifugal pump assembly according to claim 10 , wherein in the one of the functional position, in which the flow path through the impeller is closed, the impeller bears with a first peripheral edge delimiting the exit opening, on a face edge of the annular wall.

12. A centrifugal pump assembly according to claim 11 , wherein in the one of the in that functional position, in which the flow path through the impeller is closed, a flow path open to an axial face side of the impeller remains between a second peripheral edge lying opposite the first peripheral edge, and the annular wall.

13. A centrifugal pump assembly according to claim 1 , further comprising a closure element, wherein in one of the functional positions the flow path through the impeller is closed, and said one of the functional positions the closure element closes an exit opening or an entry opening of the impeller at least for the larger part by more than 90%.

14. An impeller for a centrifugal pump, the impeller comprising:
a first peripheral impeller edge surface;
a second peripheral impeller edge surface;
at least one exit opening; and
at least one entry opening defined by the first peripheral impeller edge surface and the second peripheral impeller edge surface, wherein the entry opening is situated in a peripheral section of the impeller, the first peripheral impeller edge surface being configured to be in direct contact with an annular wall when the impeller is in a first functional position, the second peripheral impeller edge surface being configured to be located at a spaced location from the annular wall to define a gap between an inner edge surface of the annular wall and the second peripheral impeller edge surface when the impeller is in the first functional position, wherein the impeller is held by a magnetic force in the first functional position and the impeller is held by a hydraulic force produced by a delivered fluid in a second functional position, wherein the hydraulic force is greater than the permanent magnetic force holding the at least one impeller in the first functional position and the hydraulic force is increased if the drive motor is switched on and the hydraulic force decreases if the drive motor is switched off.

15. An impeller according to claim 14 , further comprising a closed, suction-side, axial face side, to which the peripheral section with the entry opening is adjacent, the first peripheral impeller edge surface comprising a first diameter, the second peripheral impeller edge surface comprising a second diameter, the second diameter being less than the first diameter.

16. An impeller according to claim 15 , wherein the entry opening is configured as an annular opening extending over the complete periphery of the impeller.

17. An impeller according to claim 16 , wherein the impeller has a suction side comprising a lengthened cylindrical section which has an outer surface which is 50 to 150% of an inner cross section in an inside of the lengthened cylindrical section.

18. A centrifugal pump assembly comprising:
an electric drive motor;
a closure element comprising a closure element inner surface, the closure element inner surface being parallel to a longitudinal axis of the closure element;
an impeller movable in an axial direction between at least a first functional position and a second functional position, wherein in the first functional position a flow path through the impeller is essentially closed and in the second functional position the flow path through the impeller is opened, wherein the impeller in a first functional position is held by a magnetic force and in a second functional position is held by a hydraulic force produced by a delivered fluid, wherein the impeller is moved from the first functional position to the second functional position via the hydraulic force when the hydraulic force is greater than the magnetic force, wherein the hydraulic force increases when the electric drive motor is switched to an actuated state and the hydraulic force decreases when the electric drive motor is switched to a non-actuated state, the impeller having a first impeller peripheral surface portion and a second impeller peripheral surface portion, the first impeller peripheral surface portion being in contact with the closure element inner surface when the impeller is in the first functional position, the second impeller peripheral surface portion being located at a spaced location from the closure element to define a gap between the closure element inner surface and the second impeller peripheral surface portion, the first impeller peripheral surface portion and the second impeller peripheral surface portion being located at a spac

Assignees

• Grundfos Holding As

Inventors

• Blad Thomas

Classifications

• F05D2270/62

  Electrical actuators · CPC title

• F04D1/00

  Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps (adapted for pumping specific fluids F04D7/00; priming or boosting F04D9/00) · CPC title

• F04D29/042 Primary

  Axially shiftable rotors (F04D29/041 takes precedence {; control by creating a by-pass F04D15/0027}) · CPC title

• F04D15/0038

  by varying the effective cross-sectional area of flow through the rotor · CPC title

• F04D29/0416

  balancing pistons · CPC title