Centrifugal pump assembly comprising at least one impeller producing flow through and an annular space divided by at least two guide vanes into part-annular-spaces

Abstract

A water supply system (1) includes an electric motor (8) and a centrifugal pump (7) which is driven by the electric motor (8) and with at least one impeller (10) which produces a main delivery flow (29) through an annular space (12) as well as a cooling fluid delivery flow (30) through a space (28) surrounding the motor (8). The annular space (12) is divided by two guide vanes into part-annular-spaces (23, 24) which have a different pressure level on operation. Each part-annular-space (23, 24) is conductively connected to the space (28) which surrounds the motor (8) and through which the cooling fluid runs (FIG. 5).

Claims

1. A centrifugal pump assembly for forming a part of a water supply system, the centrifugal pump assembly comprising: an electric motor; and a single-stage or multi-stage centrifugal pump driven by the electric motor, said centrifugal pump comprising: at least one impeller which produces a main delivery flow through an annular space surrounding at least one pump stage; a space surrounding the electric motor, a cooling fluid delivery flowing through the space surrounding the electric motor; and at least two guide vanes, wherein the annular space is divided by the at least two guide vanes into part-annular-spaces, each of the part-annular spaces having a pressure level that is different than a pressure level of another one of the part-annular spaces when the at least one impeller is operated, and each part-annular-space being fluid conductively connected to the space surrounding the motor.

2. A centrifugal pump assembly according to claim 1, wherein the guide vanes are arranged diametrically in the annular space and form part of a last pump stage or are arranged after the last pump stage, the part-annular-spaces comprising a lower annular space and an upper annular space, wherein the at least two guide vanes deflect a portion of the main delivery flow to form a motor cooling flow of fluid, at least a portion of the motor cooling flow of fluid flowing in a direction opposite the main delivery flow, the lower annular space receiving the main delivery flow and the motor cooling flow of fluid, the motor cooling flow of fluid flowing in a first direction in the lower annular space, the upper annular space receiving the motor cooling flow of fluid, the motor cooling flow of fluid moving in a second direction in the upper annular space, the second direction being opposite the first direction.

3. A centrifugal pump assembly according to claim 1, wherein the annular space is delimited at least partly by a pump casing.

4. A centrifugal pump assembly according to claim 3, wherein the centrifugal pump is a multi-stage centrifugal pump with a last pump stage formed by the impeller with surrounding guide vanes in the pump casing and a first and any further pump stages are arranged within the cylinder wall which inwardly delimits the annular space of the pump and is divided in an axial direction at least in sections by the guide vanes.

5. A centrifugal pump assembly according to claim 1, wherein the guide vanes extend in one of a direction of a rotation axis of the impeller and in a direction parallel to the rotation axis of the impeller.

6. A centrifugal pump assembly according to claim 3, wherein the guide vanes extend into a region between the impeller and a face wall delimiting the pump casing.

7. A centrifugal pump assembly according to claim 6, wherein the fluid conductive connection comprises one or more conduit connections to the space surrounding the motor formed by one or more recesses in a face wall of the pump casing.

8. A centrifugal pump assembly according to claim 1, wherein the guide vanes extend radially along a face wall of a pump casing and extend axially along an outer wall of the pump casing, said outer wall outwardly delimiting the annular space.

9. A centrifugal pump assembly according to claim 1, wherein the pump is a radial centrifugal pump or a radial-axial centrifugal pump.

10. A centrifugal pump assembly according to claim 1, wherein the pump is configured for operation with a horizontally arranged rotation axis, and that the guide vanes subdividing the annular space of the pump extend essentially in a horizontal plane, in which the rotation axis also lies.

11. A centrifugal pump assembly according to claim 1, wherein the electric motor and the pump comprise a common shaft and the annular space of the pump is arranged aligned to the space which surrounds the motor.

12. A water supply system comprising a centrifugal pump assembly comprising: an electric motor; and a single-stage or multi-stage centrifugal pump driven by the electric motor, said centrifugal pump comprising: at least one impeller which produces a main delivery flow through an annular space surrounding at least one pump stage; a space surrounding the electric motor, a cooling fluid delivery flowing through the space surrounding the electric motor; at least two guide vanes, wherein the annular space is divided by the at least two guide vanes into part-annular-spaces, each of the part-annular-spaces having a pressure level that is different from a pressure level of another one of the part-annular-spaces during operation of the at least one impeller, and each part-annular-space is fluid conductively connected to the space surrounding the motor; and a housing surrounding the centrifugal pump, wherein a suction connection and a delivery connection are provided, which are arranged on a face side of the surrounding housing.

13. A water supply system according to claim 12, wherein the suction connection and the delivery connection are arranged above one another.

14. A water supply system according to claim 12, wherein: the centrifugal pump assembly further comprises a diaphragm tank and motor electronics; the electric motor is positioned in the housing; and the centrifugal pump and the electric motor are arranged at a bottom with the diaphragm tank and the motor electronics thereabove and at a top.

15. A water supply system according to claim 12, wherein the centrifugal pump is a multi-stage centrifugal pump with a last pump stage formed by the impeller with surrounding guide vanes in a pump casing and a first and any further pump stages are arranged within cylinder wall which inwardly delimits the annular space of the multi-stage centrifugal pump and is divided in an axial direction at least in sections by the guide vanes.

16. A water supply system according to claim 12, wherein the guide vanes extend into a region between the impeller and a face wall delimiting a pump casing, the part-annular-spaces comprising a lower annular space and an upper annular space, wherein the at least two guide vanes deflect a portion of the main delivery flow to form a motor cooling flow of fluid, at least a portion of the motor cooling flow of fluid flowing in a direction opposite the main delivery flow, the lower annular space receiving the main delivery flow and the motor cooling flow of fluid, the motor cooling flow of fluid flowing in a first direction in the lower annular space, the upper annular space receiving the motor cooling flow of fluid, the motor cooling flow of fluid moving in a second direction in the upper annular space, the second direction being opposite the first direction.

17. A water supply system according to claim 16, wherein the fluid conductive connection comprises one or more conduit connections to the space surrounding the motor formed by one or more recesses in a face wall of the pump casing.

18. A water supply system according to claim 16, wherein the guide vanes extend radially along a face wall of the pump casing and extend axially along an outer wall, of the pump casing, said outer wall outwardly delimiting the annular space.

19. A water supply system according to claim 16, wherein the pump is configured for operation with a horizontally arranged rotation axis, and that the guide vanes subdividing the annular space of the pump extend essentially in a horizontal plane, in which the rotation axis also lies.

20. A water supply system according to claim 19, wherein the electric motor and the pump comprise a common shaft with the rotation axis and the annular space of the pump is arranged aligned to the space which surrounds the motor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a greatly simplified longitudinal sectional view of a water supply system with a centrifugal pump;

(3) FIG. 2 is a perspective view of a part of the pump casing within the water supply system;

(4) FIG. 3 is a longitudinal sectional view of the part of the pump casing according to FIG. 2;

(5) FIG. 4 is a perspective representation of the part of the pump casing according to FIG. 3, with pump stages arranged therein; and

(6) FIG. 5 is a greatly simplified longitudinal sectional view according to FIG. 1, showing a course of the delivery flows within the water supply system, on operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) Referring to the drawings, a water supply system 1 comprises a housing 2, in which all components of the water supply system are integrated and which has a foot 3, with which the water supply system 1 stands on a floor surface for example, and, as the case may be, is anchored in this for example by screws.

(8) The water supply system 1 at its housing side which is on the left in FIG. 1 comprises a suction connection 4 as well as a delivery connection 5 at a distance thereabove. A closable drain opening 6 is provided below the suction connection 4.

(9) The lower part of the housing 2 is filled out by a multi-stage centrifugal pump 7 and an electric motor 8 which drives this, and these are arranged in a lying manner which is to say have a shaft 9 which is horizontal in operation, and which on the one hand receives the rotor of the electric motor 8 and on the other hand impellers 10 of the centrifugal pump 7.

(10) The centrifugal pump which here has four stages is designed in a closed manner in the first three stages, which means that the diffuser connecting to the respective impeller is surrounded by a cylinder wall 11 forming the inner wall of an annular space 12, whose outer wall is formed by the pump casing. The pump casing is essentially formed from two casing parts, specifically a pot-like casing part 13 as well as a casing part 14 forming the suction port of the pump. The casing part 14 is designed as a plastic injection molded part, forms the side of the water supply system 1 which comprises the suction connection 4 and the delivery connection 5, and comprises a channel 15 which leads from the annular space 12 to the delivery connection 5 and which receives a non-return valve 16 and at its free end runs out at the upper side of the housing 2, where it is closed off by a closure plug 17. The delivery connection 5 connects to this channel 15 in a transverse manner downstream of the non-return valve 16 in the flow direction. A connection 18, on which a diaphragm tank 19 forming the pressure storage means of the water supply system 1 connects, is provided offset thereto by 180. The diaphragm tank 19 is arranged above the pump 7, and connecting to this at the rear side is an electronics housing 20 which is arranged above the electric motor 8 and receives the complete control and regulation electronics of the water supply system 1.

(11) In operation, water gets through the suction connection 4 into the casing part 14, thus to the suction port of the pumps 7, from there subsequently through the individual pump stages up to the last impeller, from where it is diverted via the open diffuser yet described further below, in a main delivery flow 29, by 180 into the annular space 12, so as to get from there via the vertical channel 15 through the non-return valve 16 to the delivery connection 5 where it leaves the water supply system 1.

(12) The last impeller 10 is surrounded by guide vanes 21 and 22, in order to produce a part flow which forms the cooling fluid flow 30 for the motor 8. With regard to the guide vanes 21 it is the case of common guide vanes which are arranged radially surrounding the impeller, and correspond to common guide vanes with regard to their design and function. The guide vanes 22 which are arranged in a manner offset by 180 (with respect to the rotation axis of the pump), are however extended in the axial direction to into the annular space 12, and divide the annular space 12 into two annular space parts, specifically a lower part-annular-space 23 and an upper part-annular-space 24. These guide vanes 22 which divide the annular space 12 extend axially from a face wall 25 of the pot-like casing part 13 along the outer wall up to close to the end of the casing part 13, thus where this is flanged onto the casing part 14. The guide vanes 22 reach inwards onto the cylinder wall 11, so that the annular space 12 is divided roughly horizontally by the guide vanes 22 at least in the region of the cylinder wall 11. The guide vanes 22 are designed inwards as is the case with the guide vanes 21, in the region of the last impeller.

(13) A different pressure level in the part-annular-spaces 23 and 24 arises on operation due to the division of the annular space 12, at least in the region of the pot-like casing part 13, wherein a higher pressure prevail in the lower part-annular-space 23 than in the upper part-annular-space 24. The differences are comparatively low since the part-annular-spaces 23 and 24 are hydraulically connected towards the suction-side end of the annular space 12.

(14) The pot-like casing part 13 comprises a central recess 26 for leading through and mounting the shaft 9. The face wall 25, in a manner surrounding this recess 26 extends up to the essentially cylindrical outer side of the casing part 13. Recesses 27 which lead to an annular space 28 which connects thereto and which surrounds the stator of the electric motor 8 are in this face wall 25, in the region flush with the annular space 12, in the lower part-annular-space 23 as well as in the upper part-annular-space 24. These recesses 27 serves for permitting the cooling fluid flow 30 which is produced by the different pressure level in the part-annular-spaces 23 and 24, to get from the lower part-annular-space 23 into the lower part of the annular space 28 surrounding the electric motor 8, and permitting it to flow upwards from there and through the upper recesses 27 in the face wall 25, into the upper part-annular-space 24, so as to get from there into the main delivery flow. This pressure difference between the lower and the upper part-annular-space 23, 24 and which is produced by the guide vanes 22 is sufficient to produce an adequate cooling fluid flow 30 through the annular space 28 and thus an adequate cooling of the electric motor 8.

(15) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

APPENDIX

(16) List of Reference Numbers:

(17) 1 water supply system 20 electronics housing 2 housing of 1 21 normal guide vanes 3 foot 22 dividing guide vanes 4 suction connection 23 lower part-annular-space 5 delivery connection 24 upper part-annular-space 6 drain opening 25 face wall 7 centrifugal pump 26 central recess 8 electric motor 27 recesses in the face wall 9 shaft 28 annular space 10 impellers 29 main delivery flow 11 cylinder wall 30 cooling fluid flow 12 annular space 13 pot-like casing part of the pump casing 14 casing part of the pump casing 15 channel 16 non-return valve 17 closure plug 18 connection for the diaphragm tank 19 diaphragm tank