EP3156663A1 - Centrifugal pump assembly - Google Patents

Abstract

The Hauwasserwerk (1) has an electric motor (8) and a driven centrifugal pump (7) with at least one impeller (10) having a main flow (29) through an annular space (12) and a cooling liquid flow (30) through a motor (8) generates surrounding space (28). The annular space (12) is subdivided by two guide vanes into partial annular spaces (23, 24), which have different pressure levels during operation. Each partial annular space (23, 24) is connected to the space (28) surrounding the motor (8) through which the flow of cooling fluid passes. (Fig. 5)

Description

The invention relates to a centrifugal pump unit, in particular as part of a domestic waterworks, which has a single or multi-stage centrifugal pump, which is driven by an electric motor.

In order to dissipate the heat generated by the drive motor, it is in prior art centrifugal pump units to guide the flow of the pump along the motor so that it is not overheated. Such arrangements are known in particular for centrifugal pump units for cold water production.

The use of such centrifugal pumps in domestic water systems or pressure booster systems is state of the art. In a distributed by the applicant under the name "GRUNDFOS MQ" domestic water plant is a multi-stage centrifugal pump lying, ie arranged with a horizontal axis, which is multi-level and has a channel guide within the domestic waterworks, in which the pumped by the pump water from the last Pump stage promotes an annular space surrounding the electric motor, which in turn connects to a channel that leads to the output or pressure connection of the domestic waterworks. The constructive measures taken there for cooling the engine have proven to be ideal, since the main flow of flow flows along the outside of the electric motor and thus always ensures adequate cooling. The construction of this known domestic waterworks is relatively complex, which is why it seeks to simplify this, so that the domestic waterworks can be produced more cheaply and also application technology can be made more advantageous. However, if one fundamentally deviates from the known design principle, this also requires a change in the cooling concept for the electric motor.

Against this background, the invention has the object, a centrifugal pump unit, in particular as part of a domestic waterworks to design so that the electric motor is sufficiently cooled without the main flow must be performed along the electric motor.

The object of the invention is achieved by a centrifugal pump unit having the features specified in claim 1, and as far as the home water plant-side application, by a domestic waterworks with the features specified in claim 12. Waterworks within the meaning of the present invention is also a pressure booster. Advantageous embodiments of the invention are specified in the dependent claims of the following description and the drawings. In this case, the features specified in the dependent claims and the description in each case, but also in a suitable combination, the solution according to the invention according to claim 1 or according to claim 12 further develop.

The centrifugal pump assembly according to the invention, which in particular forms part of a domestic waterworks, has an electric motor and a driven one or more stages centrifugal pump with at least one impeller, which generates a main flow through an annular space surrounding the at least one pump stage and a cooling liquid flow through a space surrounding the engine , In this case, the annulus is divided by at least two vanes in partial annulus, the different in operation Have pressure level and each of these Teilringräume is conductively connected to the surrounding space surrounding the engine.

The basic idea of the solution according to the invention is, first of all, to use only a partial flow of the liquid conveyed by the centrifugal pump for cooling the motor, in order to be freer in design and design in this way in the ducting. Thus, a main flow is generated by a surrounding the at least one pump stage annulus, d. H. the main flow is led at the end of the pump through this annulus towards the suction side of the pump, so that the main duct is substantially in the area of the pump and not on the motor side. In order to cool the electric motor reliable and safe, however, a cooling liquid flow is diverted from the main flow and passed through a space surrounding the engine.

In order to generate this cooling liquid delivery flow, a difference in the pressure level is generated in the annular space surrounding the at least one pump stage, in which at least two guide vanes are arranged, which subdivide at least parts of this annular space into two partial annular spaces which have different pressure levels during operation. In this case, according to the invention, these partial annular spaces are each line-connected to the space surrounding the motor. By doing so in operation adjusting, albeit small pressure difference between the part ring spaces a targeted flow is generated in the space surrounding the engine, and thus ensures the required Kühlflüssigkeitsförderstrom.

On the one hand, this constructive measure ensures reliable cooling of the electric motor, but on the other hand makes it possible to configure the ducting so that the pump inlet and pump outlet are on the same side that at least the main flow through a the at least one pump stage surrounding annular space is returned to the pump inlet. As a result, a very compact construction is possible, especially when the centrifugal pump unit according to the invention forms part of a domestic waterworks. The effect of the different pressure levels in the two subspaces is formed in particular when the centrifugal pump assembly is lying, ie operated with a horizontal axis of the pump and motor. Then, in the lower part of the annular space, there may be a higher pressure level than in the upper part annular space, whereby this cooling liquid flow is generated by the space surrounding the engine. However, this effect can also be achieved in non-horizontal arrangement, it must be different in size only the hydraulic resistances of the connections between the one compartment and the pressure port and between the other compartment and the pressure port.

Advantageously, according to an embodiment of the invention, the vanes part of the last pump stage or this downstream. They are preferably arranged diametrically in the annular space, preferably in such a way that they form an imaginary dividing plane, which at least partially divides the annular space of the pump preferably substantially horizontally.

Advantageously, the annular space surrounding the at least one pump stage, at least partially limited by the pump housing. The construction according to the invention can then take place largely by utilizing already existing components.

It is particularly advantageous if, in a multi-stage design of the centrifugal pump, the last pump stage is formed by the impeller with the surrounding normal and the annular space dividing vanes in the pump housing and the first and optionally further pump stages are arranged therebetween within a cylinder jacket, which limits the annular space of the pump inwardly and which is divided at least in sections by the guide vanes in the axial direction. Divided in the axial direction, it is to be understood that the dividing plane formed by the vanes extends through or parallel to the pump axis and preferably horizontally.

Advantageously, these vanes dividing the annulus are designed and arranged so that they extend in the direction of the axis of rotation of the impeller or in a direction parallel thereto and thus protrude into the annulus, ie at the same time part of the diffuser for the last pump stage and release means for generating the pressure difference form for the coolant flow. Extend the vanes in the area between the impeller and an end wall, preferably the end wall bounding the pump housing, to the end wall, which is close to the electric motor. As a result, a comparatively high pressure difference of the partial annular spaces is achieved, since no hydraulic short circuit can occur in this area. In this case, the line connections to the space surrounding the motor are preferably formed by recesses in this end wall of the pump housing.

According to an advantageous embodiment of the invention, the guide vanes forming the partial annular spaces extend radially along the end wall of the pump housing facing the electric motor and axially along an outer wall defining the annular space, preferably the pump housing. They thus form, on the one hand, part of the diffuser of the last pump stage and, on the other hand, walls which delimit the partial annular spaces from each other. Advantageously, these vanes are integral with the pump housing formed, which has both the end wall to the electric motor and the surrounding outer wall.

In particular, in the above-described ducting, in which the pumped liquid is conveyed from the suction port of the first pump stage to the stator of the last pump stage substantially in the axial direction of the pump and then through the annular channel in the opposite direction, it is advantageous to use the pump as radial or radial / Form axial centrifugal pump.

The pump is advantageously intended and designed for operation with a horizontally arranged axis of rotation, wherein the guide vanes dividing the annulus of the pump essentially extend in a horizontal plane in which the axis of rotation lies or parallel and / or slightly oblique (up to a maximum of 30 °) to) runs.

It is advantageous if motor and pump have a common shaft and the annular space of the pump is arranged in alignment with the space surrounding the motor, which is preferably also designed as an annular space.

The constructive embodiments described above are particularly advantageous when using the centrifugal pump assembly according to the invention in a domestic waterworks. The domestic waterworks can be made much cheaper by these structural features, both in terms of manufacturing and assembly and in terms of its handling. Thus, the domestic waterworks according to the invention such a centrifugal pump unit and has its suction port and its pressure port arranged on the same side, preferably one above the other at an end face of the surrounding housing. This arrangement is possible because the flow through the annular space of the pump is returned in the direction of the suction side, so that the pressure connection of the domestic waterworks can be without elaborate internal ducting on the same side as the suction connection.

According to an advantageous embodiment of the invention, the domestic water plant on a surrounding housing, in the pump and motor below, a diaphragm pressure vessel and the engine electronics are arranged above and above. In this case, the engine electronics over the engine and the diaphragm pressure vessel is advantageously arranged above the pump. In this way, electrical and hydraulic assemblies are locally separated from each other within the housing of the domestic water plant, which is beneficial. In this case, in an advantageous embodiment, the channel guide can be placed on the side of the pump housing to which the suction and pressure connection are located.

Fig. 1

ein Hauswasserwerk mit einer Kreiselpumpe in stark vereinfachter Darstellung im Längsschnitt,

Fig. 2

eine perspektivische Ansicht eines Teils des Pumpengehäuses innerhalb des Hauswasserwerks,

Fig. 3

den Teil des Pumpengehäuses gemäß Fig. 2 im Längsschnitt,

Fig. 4

in perspektivischer Darstellung den Teil des Pumpengehäuses gemäß Fig. 3 mit darin angeordneten Pumpenstufen und

Fig. 5

den Verlauf der Förderströme innerhalb des Hauswasserwerks im Betrieb in einer Darstellung entsprechend Fig. 1.

The invention is explained in more detail with reference to an embodiment shown in the drawings. Show it:

Fig. 1

a domestic waterworks with a centrifugal pump in a very simplified representation in longitudinal section,

Fig. 2

a perspective view of a portion of the pump housing within the domestic waterworks,

Fig. 3

the part of the pump housing according to Fig. 2 in longitudinal section,

Fig. 4

in a perspective view of the part of the pump housing according to Fig. 3 with arranged therein pump stages and

Fig. 5

the course of the flow within the domestic waterworks in operation in a representation accordingly Fig. 1 ,

The domestic waterworks 1 has a housing 2, in which all components of the domestic waterworks are incorporated and which has a foot 3, with which the domestic waterworks 1 stands on a floor surface, for example, and is optionally anchored in this, for example by screws.

The house waterworks 1 has its in Fig. 1 left side of the housing a suction port 4 and at a distance above a pressure port 5. Below the suction connection 4, a closable discharge opening 6 is provided.

The lower part of the housing 2 is filled by a multi-stage centrifugal pump 7 and a driving electric motor 8, which are arranged horizontally, that is a horizontal shaft 9 in operation, which on the one hand receives the rotor of the electric motor 8 and the other hand, centrifugal 10 of the centrifugal pump 7.

The here four-stage centrifugal pump is designed to be closed in the first three stages, that is, the adjacent to the respective impeller diffuser is surrounded by a cylinder wall 11 which forms the inner wall of an annular space 12 whose outer wall is formed by the pump housing. The pump housing is essentially formed from two housing parts, namely a pot-shaped housing part 13 and a suction port of the pump forming housing part 14. The housing part 14 is formed as a plastic injection molding, forms the suction port 4 and the pressure port 5 comprehensive side of the domestic waterworks 1 and has a from the annular space 12 to the pressure port 5 leading channel 15, which is a check valve 16 receives and opens at its free end to the top of the housing 2, where it is closed by a sealing plug 17. The pressure port 5 connects to this channel 15 in the flow direction behind the check valve 16 transversely. Offset by 180 °, transversely, a connection 18 is provided, to which a membrane pressure vessel 19 connects, which forms the pressure accumulator of the domestic waterworks 1. The diaphragm pressure vessel 19 is arranged above the pump 7, on the rear side of this an electronics housing 30 connects, which is arranged above the electric motor 8 and the entire control and regulating electronics of the domestic waterworks 1 receives.

In operation, the water passes through the suction port 4 in the housing part 14, ie to the suction port of the pump 7, from there through the individual pump stages to the last impeller, from where it via the still described below open diffuser in a main flow 29 by 180 ° is redirected to the annular space 12, to get from there via the vertical channel 15 through the check valve 16 to the pressure port 5, where it leaves the house waterworks 1.

In order to generate a partial flow, which forms the cooling liquid flow 30 for the motor 8, the last impeller 10 is surrounded by vanes 21 and 22. In the vanes 21 are conventional vanes, which are arranged radially surrounding the impeller and correspond to the usual design and function vanes. However, the guide vanes 22, which are arranged offset by 180 ° (relative to the axis of rotation of the pump) are extended in the axial direction into the annulus 12, they divide the annulus 12 into two annulus parts, namely a lower part annulus 23 and an upper part annulus 24. This annular space 12 dividing vanes 22 extend axially from an end wall 25 of the cup-shaped housing part 13 on the outer wall along to near the end of the housing part 13, ie where it is flanged to the housing part 14. Inwardly, the guide vanes 22 extend up to the cylinder wall 11, so that at least in the region of the cylinder wall 11 of the annular space 12 is divided by the guide vanes 22 approximately horizontally. In the region of the last impeller, the vanes 22 are formed inwardly as the vanes 21.

By this division of the annular space 12, at least in the region of the cup-shaped housing part 13, arises in operation, a different pressure level in the partial annular spaces 23 and 24, wherein in the lower part of annulus 23, a higher pressure prevails than in the upper part annulus 24. The differences are relatively small to the suction end of the annular space 12, the partial annular spaces 23 and 24 are hydraulically connected.

The cup-shaped housing part 13 has a central recess 26 for the implementation and storage of the shaft 9. Surrounding this recess 26, the end wall 25 extends to the substantially cylindrical outer side of the housing part 13. In this end wall 25 are in the region aligned with the annular space 12 in the lower part of the annulus 23 and in the upper part annulus 24 recesses 27, to an adjoining, the Stator of the electric motor 8 lead surrounding annular space 28. These recesses 27 serve to allow the cooling liquid flow 30, which is generated by the different pressure level in the partial annular spaces 23 and 24, to pass from the lower partial annular space 23 into the lower part of the annular space 28 surrounding the electric motor 8, from there upwards and through the let upper recesses 27 in the end wall 25 in the upper part of annulus 24 to flow and then to get from there into the main flow. This pressure difference between the lower and the upper partial annular space 23, 24 produced by the guide vanes 22 is sufficient, to generate a sufficient coolant flow 30 through the annulus 28 and thus sufficient cooling of the electric motor 8.

LIST OF REFERENCE NUMBERS

1

Hauwasserwerk

2

Housing of 1

3

foot

4

suction

5

pressure connection

6

drain hole

7

rotary pump

8th

electric motor

9

wave

10

impellers

11

cylinder wall

12

annulus

13

cup-shaped housing part of the pump housing

14

Housing part of the pump housing

15

channel

16

check valve

17

sealing plug

18

Connection for diaphragm pressure vessel

19

Diaphragm pressure vessel

20

electronics housing

21

normal vanes

22

dividing vanes

23

lower part-ring space

24

Upper part-ring space

25

bulkhead

26

central recess

27

Recesses in the front wall

28

annulus

29

Main flow

30

Coolant flow

Claims (13)

Centrifugal pump unit, in particular as part of a domestic waterworks (1), with an electric motor (8) and a driven one or more stages centrifugal pump (7) with at least one impeller (10), which a main flow (29) surrounding the at least one pump stage Annular space (12) and a cooling liquid flow (30) by a motor (8) surrounding space (28) generated, wherein the annular space (12) is divided by at least two vanes (22) in partial annular spaces (23, 24), which in operation have different pressure level, and each partial annular space (23, 24) with the motor (8) surrounding space (28) is conductively connected. Centrifugal pump unit according to claim 1, characterized in that the preferably diametrically in the annular space (12) arranged vanes (22) form part of the last pump stage or are arranged downstream thereof. Centrifugal pump assembly according to claim 1 or 2, characterized in that the annular space (12) is at least partially limited by the pump housing (13). Centrifugal pump assembly according to claim 3, characterized in that the centrifugal pump (7) is formed in several stages, the last pump stage by the impeller (19) with the surrounding vanes (21, 22) in the pump housing (13, 14) is formed and the first and optionally further pump stages are arranged within a cylinder jacket (11) which limits the annular space (12) of the pump (7) inwardly and which is divided at least in sections by the guide vanes (22) in the axial direction. Centrifugal pump unit according to one of the preceding claims, characterized in that the guide vanes (22) also extend in the direction of the axis of rotation of the centrifugal wheel (10) or in a direction parallel thereto. Centrifugal pump assembly according to one of the preceding claims, characterized in that the guide vanes (22) in the region between the centrifugal gear (10) and a preferably the pump housing (13, 14) delimiting end wall (25) extend. Centrifugal pump unit according to one of the preceding claims, characterized in that the line connections to the motor (8) surrounding space (28) by recesses (27) in an end wall (25) of the pump housing (13, 14) are formed. Centrifugal pump unit according to one of the preceding claims, characterized in that the guide vanes (22) extend radially along an end wall (25) of the pump housing (13, 14) and axially along an outer wall, in particular of the pump housing (13, 13) limiting the annular space (12) to the outside. 14). Centrifugal pump unit according to one of the preceding claims, characterized in that the pump (7) is a radial or radial / axial centrifugal pump. Centrifugal pump unit according to one of the preceding claims, characterized in that the pump (7) is intended for operation with a horizontally arranged axis of rotation and that the guide vanes (22) dividing the annulus (12) of the pump (7) extend substantially in a horizontal plane in which the axis of rotation also lies. Centrifugal pump unit according to one of the preceding claims, characterized in that motor (8) and pump (7) have a common shaft (9) and the annular space (12) of the pump (7) in alignment with the space surrounding the motor (8) ( 28), preferably annular space (12) is arranged. Domestic waterworks with a centrifugal pump unit according to one of the preceding claims, characterized in that a suction connection (4) and a pressure connection (5) are provided, which are preferably arranged one above the other at an end face of the surrounding housing (2). Domestic waterworks according to claim 9, characterized in that in the surrounding housing (2) pump (7) and motor (8) below, a diaphragm pressure vessel (19) and the engine electronics above and above are arranged.

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