EP2236839B1 - Centrifugal pump assembly - Google Patents

Description

The invention relates to a centrifugal pump unit.

Centrifugal pump units are used in many areas for the promotion of liquids, especially water, for example as heating circulation pumps. Known centrifugal pump units usually have a pump housing made of metal, which is designed as a casting. In addition, it is known to wrap such centrifugal pump units with a thermal insulation, for example, to avoid precipitation of condensation water on the outside in cold water pumps or to reduce heat losses in hot water pumps. For example, molded parts made of a foam material are adapted to the outer contour of the pump housing and enclose the pump housing from the outside. In addition, this insulation layer can be outwardly clad, for example, by a plastic shell, which gives the pump unit an appealing appearance.

Pump casings made of cast metal have the disadvantage that they are expensive to manufacture and the shape of the flow paths in the interior and in particular the surface design of the flow paths is limited, so that flow optimization is difficult.

DE 30 11 888 A1 discloses a circulating pump assembly with an insert which is inserted from plastic, which the flow paths in Interior of the housing forms. The remaining space between this housing insert and the pump housing is filled with sand for damping purposes.

DE 30 11 888 A1 discloses a circulating pump assembly with an insert made of plastic and which forms the flow paths inside the housing. In some sections, a clearance remains between this housing insert and the pump housing, which is filled with sand for damping purposes. In other sections, the insert is applied directly to the housing. The inlet channel is formed between the insert and a housing wall.

DE 31 09 624 A1 discloses a circulating pump assembly having a metallic pump housing surrounded by shells of insulating material.

US 2,976,809 such as EP 0 849 473 A1 disclose centrifugal pump units with a pump housing made of plastic, which is surrounded by a supporting metal structure.

EP 1 079 115 A2 discloses a pump housing for a centrifugal pump assembly, which is made of plastic.

It is therefore an object of the invention to provide an improved centrifugal pump unit, which has a thermal insulation and Incidentally, an optimized design of the flow paths in the interior while allowing cost-effective production permits.

This object is achieved by a centrifugal pump unit having the features specified in claim 1. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

The centrifugal pump unit according to the invention has a pump housing. In this pump housing, the flow paths for the medium to be delivered, in particular a liquid to be conveyed are formed. In the pump housing, one or more impellers are arranged in a known manner, which promote the medium. To the pump housing, a motor or stator housing may be attached, in which an electric motor for driving the impeller is arranged.

According to the invention, the pump housing is designed in several parts. It initially has an inner housing made of plastic. This is formed fluid-tight and defined in its interior, the flow paths for the medium or fluid to be delivered. The design of the inner housing made of plastic allows cost-effective production. In addition, the flow paths can be made with greater degrees of freedom and precision than in metal casting, so that the flow paths can be designed in an optimized manner. The inner housing thus houses all flow channels or parts and seals the flow paths to the outside. On its outer side, the inner housing is surrounded by a thermal insulation layer, which thermally insulates the inner housing and thus the flow-leading parts to the outside.

In addition, an outer housing is provided, which faces away from the insulating layer on its outer side, that is, the inner housing Surrounds page. This outer housing is designed to be load-bearing, so that it can absorb the forces occurring in the pump housing and acting on the pump housing. These are in particular the pressure forces occurring in the inner housing due to the fluid to be delivered. These forces are transmitted from the inner housing to the outer housing and received by the outer housing. This makes it possible to dimension the inner housing itself less strong, so that the design of plastic is easily possible here. Furthermore, the wall thicknesses can be reduced, whereby the material costs can be reduced and, on the other hand, greater freedom is given in the design of the flow paths in the inner housing. The inner housing thus has the primary task of defining the flow paths and sealing off to the outside. However, it does not have to absorb only the forces occurring, but rather they are partly, ideally for the most part, taken up by the outer housing, which forms a mechanically bearing element of the pump housing. Also forces acting externally on the pump assembly, for example holding forces, are ideally absorbed by the outer housing. Thus, preferably, a stator or motor housing is connected to the supporting outer housing, so that no forces are transmitted to the inner pump housing of this.

The insulating layer is made of plastic, in particular in the form of a foam material. These may be conventional insulation materials available on the market. In particular, it is preferably materials from which prefabricated molded parts can be produced, which can be attached to the inner housing from the outside.

The outer housing may also be formed of plastic, wherein the housing is dimensioned so that the forces occurring can be absorbed or transmitted by the housing, without causing damage or undesirable deformation of the housing. However, the outer housing is particularly preferably at least partially, ideally made entirely of metal. The outer housing can be made as a casting of metal or z. B. be formed from sheet metal. The formation of the outer housing made of metal is much easier than that Forming the inner housing, since it does not have to have such complex shapes as the flow channels in the interior of the inner housing. In this respect, the production is much easier and cheaper. In addition, the outer metal housing compared to the outer plastic housing has the advantage that it forms a resistant housing of the pump unit to the outside, so that it is protected against damage, especially during installation and transport. In particular, the insulation layer is protected to the outside. Particularly preferably, the outer housing may be formed of aluminum.

The inner housing is preferably made as an injection molded part. In injection molding, even complicated shapes can be inexpensively formed from plastic. In addition, high surface qualities can be achieved, which is particularly advantageous for the flow paths in the interior of the inner housing.

More preferably, the inner housing is made of a composite material, in particular of a fiber-reinforced plastic. Such a plastic has a high strength. In particular, sufficient strength can be realized with comparatively thin wall thicknesses. Also, a sufficient compressive strength against the pressure prevailing in the interior of the inner housing fluid pressures can be realized. In particular, it is ensured that even with high internal pressures, the inner housing retains its defined shape. In addition, such a fiber-reinforced plastic can also be processed by injection molding in the manner described above.

It is further preferably possible that the inner housing, the insulating layer and / or the outer housing is in each case composed of several parts. Thus, the inner housing can be composed of several parts to the cavities formed inside for the flow paths without cores, in particular to be able to train lost cores cost. Thus, first several Enzelteile the inner housing, for example, be manufactured as injection molded parts and then connected to each other. The connection can be done for example by welding or gluing or in another suitable manner, for example, non-positively or positively. In this case, a fluid-tight connection between the parts is preferably created so that the interior spaces of the inner housing, which are bounded outwards by the parts, are sealed to the outside in a fluid-tight manner.

The insulating layer may also be formed from a plurality of individual parts, in particular moldings, which are attached from the outside to the inner housing in order to enclose this. The design of several parts a simple assembly of prefabricated items is possible. The same applies to the outer housing, which may be formed of several parts or shells, which are placed from the outside around the inner housing with the adjacent insulating layer to enclose them. In this case, the individual parts of the outer housing can be mechanically connected to one another in a suitable manner, for example screwed or in other suitable manner non-positively and / or positively engaged with each other. The outer housing thus arranged can then simultaneously hold together the several individual parts of the insulating layer, so that they do not require individual mechanical connections.

According to a particular embodiment, the insulating layer may be formed of a material which is injected into a space defined between the inner and outer housing. Thus, first, the outer housing can be placed around the inner housing, wherein the inner and outer housings are designed so that between the two Free space remains. By means of one or more suitable injection openings in the outer housing, the material for the insulation layer can then be injected into the free space and distributed there. For example, the free space can be foamed up. In this way, the insulation layer can be formed very inexpensively, since a separate shaping of individual parts for the insulation layer is not required.

Furthermore, it is preferred that at least one support element for transmitting power from the inner housing to the outer housing is arranged between the inner housing and the outer housing. Due to the pressure caused by the fluid inside the inner casing, the inner casing tends to expand outwardly. This can counteract support elements between the outer and inner housing by transmitting outwardly directed forces from the inner housing to the outer housing, wherein the outer housing itself is formed so dimensionally stable that it can absorb the transmitted forces. Preferably, a plurality or a plurality of support elements are provided, which are arranged distributed over the outer surface of the inner housing, so that forces can be transmitted in all directions to the outer housing. In this way, the inner housing can be relieved in all areas of the forces generated by the internal pressure.

The at least one support element preferably rests on the outer housing and / or is formed as part of the outer housing. That is, the support member is preferably on the inside of the outer housing so that forces can be transmitted from the support member to the outer housing. It is possible that the support element or a part of the support element is made as part of the outer housing, in particular integrally formed therewith. In particular, when the outer housing is manufactured as a casting, it is easily possible to cast such support elements with.

Alternatively or additionally, the at least one support element rest against the inner housing and / or be formed as part of the inner housing. Thus, a secure power transmission from the inner housing to the support member allows. The support member may be integrally formed with the inner housing or fixedly connected thereto. For example, the support element may be formed together with the inner housing as a casting, in particular as an injection molded part made of plastic. The support members may also be formed so as to be formed of two sections, one part fixedly formed on the inner housing and one fixed to the outer housing, both parts engaging each other for power transmission when the outer housing is mounted to the inner housing is.

Particularly preferably, the at least one support element is designed as a rib, which extends transversely, preferably substantially normal to the outer surface of the inner housing and / or to the inner surface of the outer housing. The rib thus extends from the inner housing substantially in the radial direction to the outer housing and can transmit the outwardly directed pressure forces, which are caused by the internal pressure in the inner housing, directly in the direction of action of the forces on the outer housing. In this way undesirable moments in the housing structure are avoided.

More preferably, at least two support elements formed as a rib are present, which extend in two mutually non-parallel planes. This makes it possible that forces which are transmitted in the longitudinal direction of the ribs can be transmitted in different spatial directions from the fin housing to the outer housing. Thus, preferably, all pressure forces caused by the internal pressure in the inner housing can be dissipated to the outer housing so that it does not come to deformations or damage to the inner housing.

According to a particular preferred embodiment, at least one support element may have at least one elastic section. This embodiment allows for an elastic deformation of the support element. Thus, the support elements can absorb minor deformations during operation of the pump without damage. In addition, they allow a backlash-free assembly between the inner and outer housing.

More preferably, the support elements are preferably formed of a heat-insulating material to prevent unwanted heat transfer from the inner housing to the outer housing. For example, the support elements of a plastic material, which is poorly thermally conductive, are formed. This may further preferably be the same material from which the inner housing is formed. The outer housing is preferably well thermally conductive, in particular made of metal. In this way, especially when used as a cold water pump condensation on the outer casing can be prevented.

According to a further preferred embodiment, the inner housing has at least one replaceable connecting flange. The means, the connection of the flange is formed as a separate component and preferably releasably connected to the inner housing. This makes it possible to easily replace the connection flange, in order to allow the connection of the inner housing to different mating flange of subsequent piping. In this way it is avoided that different inner housing and different pump units must be provided for different connections, but only the connection flanges can be replaced depending on the required mounting.

More preferably, the pump housing has at least one connection flange tightly connected to the inner housing, which is in engagement with the outer housing in engagement. The connection flange is so tightly connected to the inner housing that an outwardly sealed flow path through the connection flange is provided through the inner housing. At the same time, the connection flange is engaged or connected to the outer housing in such a way that forces acting on the connection flange are transmitted to the outer housing and thus the load on the inner housing can be prevented in the case of externally acting forces. It is thus created a bearing connection between the outer housing and flange. A stator housing or electric motor is preferably connected to the outer housing so that the outer housing bears the weight of the stator housing or of the electric motor and thus the inner housing is kept largely free from external forces. The stator housing or a part of the stator housing may also be formed integrally with at least a part of the outer housing.

Fig. 1

eine schematische Explosionsansicht eines erfindungsgemäßen Kreiselpumpenaggregats,

Fig. 2

eine Schnittansicht des Kreiselpumpenaggregates gemäß Fig. 1,

Fig. 3

eine vollständige Explosionsansicht des Kreiselpumpenaggregates gemäß Fig. 2 und 3,

Fig. 4

eine Explosionsansicht eines Kreiselpumpenaggregates gemäß einer zweiten Ausführungsform,

Fig. 5

eine perspektivische Gesamtansicht eines Kreiselpumpenaggregates gemäß einer weiteren Ausführungsform der Erfindung,

Fig. 6

eine Schnittansicht eine Kreiselpumpenaggregates gemäß einer weiteren Ausführungsform der Erfindung,

Fig. 7

eine teilweise geschnittene perspektivische Ansicht eines Kreiselpumpen gemäß einer weiteren Ausführungsform der Erfindung und

Fig.8

eine teilweise geschnittene perspektivische Ansicht eines Kreiselpumpenaggregates gemäß einer weiteren Ausführungsform der Erfindung.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

Fig. 1

a schematic exploded view of a centrifugal pump assembly according to the invention,

Fig. 2

a sectional view of the centrifugal pump assembly according to Fig. 1 .

Fig. 3

a full exploded view of the centrifugal pump assembly according to Fig. 2 and 3 .

Fig. 4

an exploded view of a centrifugal pump assembly according to a second embodiment,

Fig. 5

an overall perspective view of a centrifugal pump assembly according to another embodiment of the invention,

Fig. 6

a sectional view of a centrifugal pump assembly according to another embodiment of the invention,

Fig. 7

a partially cutaway perspective view of a centrifugal pump according to another embodiment of the invention and

Figure 8

a partially cutaway perspective view of a centrifugal pump assembly according to another embodiment of the invention.

Fig. 1 shows a first embodiment of a centrifugal pump assembly according to the invention. The centrifugal pump assembly has a pump housing 2 with axially attached connection flanges 4. In addition, a motor or stator housing 6 is inserted laterally into the pump housing 2. The connecting flanges 4 are interchangeable designed so that different connection flanges 4 can be used with the pump housing 2. Thus, the centrifugal pump unit can be adapted to different mating flange only by replacing the connection flanges, without having to replace or change the pump housing 2 itself.

Based on Fig. 2 the further construction of the pump housing 2 will be explained. The pump housing 2 has an inner housing 8, which has flow paths 10 for a fluid or medium to be delivered by the centrifugal pump assembly. In particular, in the inner housing 8, a pump chamber 12 is formed, in which a, not shown here, impeller is arranged. The impeller is driven in a known manner by an electric motor arranged in the stator housing 6. The inner housing 8 is fluid-tight as an injection molded part made of plastic, preferably fiber-reinforced plastic. The pump housing can be manufactured, for example, as an injection molded part.

Outside, the inner housing 8 is surrounded by an outer housing 14. The outer housing 14 is preferably formed of metal and gives the pump housing 2, the mechanical strength, which does not have the inner plastic housing alone. Between the inner housing 8 and the outer housing 14, an insulating layer is arranged in the form of an insulating body. This consists for example of a foamed plastic. In the insulating body 16 free spaces are formed, in which support elements 18 are located, which allow a power transmission from the inner housing 8 to the outer housing 14. The support elements 18 are formed in the example shown as parallel ribs. In this case, the support elements 18 are formed in the example shown here as a separate support body, which is inserted between the inner housing 8 and the outer housing 14. However, it is to be understood that the support members 18 could also be formed integrally with the inner housing 8 or the outer housing 14.

The flanges 4, as well as the stator housing 6 are mechanically connected directly to the outer housing 14, so that a power transmission directly to the outer housing 14 is possible, and the outer housing 14 preferably absorbs all significant forces. Thus, the inner housing 8 can be relieved. This makes it possible to form the inner housing 8 thin-walled, so that the inner housing 8 can be shaped in such a way that primarily the flow paths 10 can be optimized to improve the flow guidance.

As in the exploded view in Fig. 3 can be seen, the outer housing 14 is composed of 2 cup-shaped parts 14a and 14b. These shells can be easily formed as castings, for example made of aluminum. It is preferred that the outer housing is made of a good heat-conducting material, ie preferably metal. Thus it can be achieved that the outer housing 14 due to the underlying insulating 16 easily assumes the ambient temperature, so that in the promotion of cold media condensation of water on the outer casing can be prevented. Also, the insulation body 16 is composed of two parts 16a and 16b, which are formed in a half-shell shape. Thus, the parts 16a and 16b enclose the inner housing 8. Due to the shared design of the insulating body, this is also inexpensive to manufacture and easy to install. The parts 14 a and 14 b of the outer housing 14 are preferably held together by screws or bolts which extend through the insulating body 16, but are not connected to the inner housing 8. The insulating body 16 is fixed between the inner housing 8 and the outer housing 14. The stator housing 6 can be connected by screws or bolts to the part 14 a of the outer housing 14. The support members 18 extend in columns in the parts 16 a and 16 b of the insulator 16. The support members 18 may be used as a separate component in the form of a support body, in which all support elements 18 are connected to each other, or be formed integrally with the inner housing 8. The support elements 18 are preferably also formed of plastic, so that they act thermally insulating and avoid heat transfer between the inner housing 8 and the outer housing 14 as possible. Nevertheless, the support elements 18 abut both the inner housing 8 and on the inside of the outer housing 14 in order to enable a power transmission.

Also, the inner housing 8 may be composed of two parts to simplify the production. Thus, the inner housing 8 may be divided along the plane 20, so that the two parts of the inner housing 8 may preferably be manufactured without undercuts by injection molding. Subsequently, the two parts can be connected to one another, for example, welded together along the dividing plane 20.

Fig. 4 shows a further embodiment of the invention, similar to the embodiment in Fig. 3 , The embodiment corresponds essentially to the basis of Fig. 1 to 3 described embodiment, but differs in some points described below. Thus, in the embodiment according to Fig. 4 the rib-shaped support elements 18 'not all parallel to each other but in mutually angled planes. As a result, a better power transmission from the inner housing 8 is achieved on the outer housing 14 in all directions. In addition, the inner housing 8 is here along a different dividing plane 20 'divided. That is, the inner housing 8 is made of two parts, which are welded together along the dividing plane 20 '. Further, in this embodiment, the stator housing 6 is integrally formed with the part 14 a of the outer housing 4.

The embodiment according to Fig. 5 Also, in this embodiment, the outer casing 14 is formed of two parts, and in this embodiment, the two parts do not abut on a plane plane but are divided along a stepped dividing line 22 , Also, the flanges 4 are in the embodiment according to Fig. 5 differently shaped in their shape. However, it should be understood that in the embodiment according to Fig. 1 to 4 the flanges can be designed accordingly, or in the embodiment according to Fig. 5 the flanges could be designed according to the first embodiment.

In the embodiment according to Fig. 6 a part of the stator housing 6 is integrally formed with the part 14 a of the outer housing. For example, in this embodiment, the insulating layer 16 'may be injected into a cavity between the outer casing 14 (14a, 14b) and the inner casing 8. The inner housing 8 is also composed of several parts here. The two parts are joined together along the dividing line 24, for example welded together tightly. The flanges 4 are also here with the outer housing 14 into engagement, so that a power transmission from the flanges directly to the outer housing is possible. In addition, web-shaped or rib-shaped support elements 18 are also provided in this embodiment between the inner housing 8 and the outer housing 14, which sections are integrally formed either with the inner housing 8 or the outer housing 14. The individual sections abut each other for power transmission, so that the support elements 18 are in communication with or in contact with both the inner housing 8 and the outer housing 14.

In the embodiments according to Fig. 7 and Fig. 8 the support elements 18 "are grid-shaped or honeycomb-shaped in Fig. 7 the lattice structure of the support elements 18 "is honeycomb-shaped and is preferably formed as a composite material as part of the inner housing 8. In the embodiment according to FIG Fig. 8 the support elements 18 "are formed integrally with the outer housing 14, preferably as a metal structure." The cavities 25 in the lattice structure of the support element 18 "can additionally be foamed with an insulating material. In the embodiment according to Fig. 8 it is further preferred that the support elements 18 "are not in direct contact with the inner housing 8, but that the inner housing 8 is first by a in Fig. 8 Is not shown insulating layer or an insulating body is sheathed, on the outside of the support body 18 "or the lattice structure of the support body 18" comes to rest. This insulating body can also be produced in one piece with the foaming of the cavities 25. In addition, it is conceivable to provide additional support elements on the inner housing 8, which come into contact with the support elements 18 ", which are formed on the outer housing 14. In this way, a direct heat transfer between the inner housing 8 and the outer housing 14 via the support elements 18th "prevented. The support elements 18 "in the form of a grid or honeycomb structure are so stiff that forces can be reliably transmitted from the inner housing 8 to the outer housing 14. The walls of the honeycombs preferably extend substantially perpendicular to the inner surface of the outer housing 14 or The outer surface of the inner housing 8. Thus, the walls of the honeycomb structure extend substantially in the direction of force of the forces to be transmitted Fig. 8 the outer housing 14 is formed divided. The division line 26 is similar to the dividing line 22 in FIG Fig. 5 ,

Also in the embodiment according to Fig. 7 and 8th the flanges are formed so that they are positively engaged with the outer housing 14, so that forces from the flanges 4 directly to the outer housing 4 can be transmitted. For this purpose, the outer housing 14 engages with a projection in a circumferential groove 28 of the flange 4 a.

Moreover, in the embodiment according to Fig. 7 a part of the stator housing 6 is formed integrally with the outer housing 14. The remaining features of the embodiments according to Fig. 7 and 8th correspond to the above-mentioned embodiments.

LIST OF REFERENCE NUMBERS

2 -

pump housing

4 -

flange

6 -

stator

8th -

inner housing

10 -

flow paths

12 -

pump room

14, 14, a, 14b -

outer casing

16, 16 '-

insulator

18, 18 ', 18 "-

support elements

20 -

parting plane

22, 24 -

Dividing lines

25 -

cavities

26 -

dividing line

28 -

groove

Claims (15)

1. A centrifugal pump assembly with a pump housing (2) which is characterised by
   an inner housing (8) of plastic which is designed in a fluid-tight manner and defines the flow paths (10) for the fluid to be delivered,
   a thermal insulation layer (16, 16') of plastic which surrounds the inner housing (8) at its outer side, and
   a supporting outer housing (14) which surrounds the insulation layer (16, 16') at the outside.
2. A centrifugal pump assembly according to claim 1, characterised in that the insulation layer (16, 16') is manufactured in the form of a foam material.
3. A centrifugal pump assembly according to claim 1 or 2, characterised in that the outer housing (14) at least partly is manufactured of metal.
4. A centrifugal pump assembly according to one of the preceding claims, characterised in that the inner housing (8) is manufactured as an injection moulded part.
5. A centrifugal pump assembly according to one of the preceding claims, characterised in that the inner housing (8) is manufactured of a composite material, in particular of a fibre-reinforced plastic.
6. A centrifugal pump assembly according to one of the preceding claims, characterised in that the inner housing (8), the insulation layer (16, 16') and/or the outer housing (14) are composed in each case of several parts.
7. A centrifugal pump assembly according to one of the preceding claims, characterised in that the insulation layer (16, 16') is formed of a material which is injected into a free space defined between the inner housing (8) and outer housing (14)
8. A centrifugal pump assembly according to one of the preceding claims, characterised in that at least one support element (18, 18') for force transmission from the inner housing (8) onto the outer housing (14) is arranged between the inner housing and the outer housing (14).
9. A centrifugal pump assembly according to claim 8, characterised in that the at least one support element (18, 18', 18") bears on the outer housing (14) and/or is designed as part of the outer housing (14).
10. A centrifugal pump assembly according to claim 8 or 9, characterised in that the at least one support element (18, 18', 18") bears on the inner housing (8) and/or is designed as part of the inner housing (8).
11. A centrifugal pump assembly according to one of the claims 8 to 10, characterised in that the at least one support element (18, 18', 18") is designed as a rib, which extends transversely, preferably essentially normally to the outer surface of the inner housing (6) and/or to the inner surface of the outer housing (14).
12. A centrifugal pump assembly according to claim 11, characterised in that at least two support elements (18, 18") which are designed as a rib and which extend in two planes which are not parallel to one another are present.
13. A centrifugal pump assembly according to one of the claims 8 to 12, characterised in that the at least one support element (18, 18', 18") comprises at least one elastic section.
14. A centrifugal pump assembly according to one of the preceding claims, characterised in that the inner housing (8) comprises at least one exchangeable connection flange (4).
15. A centrifugal pump assembly according to one of the preceding claims, characterised in that the pump housing (2) comprises at least one connection flange (4) which is connected to the inner housing (8) in a tight manner and which is engaged with the outer housing (14) in a supporting manner.

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