EP3085961B1 - Multi-stage radial pump - Google Patents

Description

The invention relates to a multi-stage centrifugal pump with the features specified in the preamble of claim 1.

The starting point of the invention is formed by centrifugal pumps, as are known, for example, from the CR and CRE pump series from Grundfos. These are multi-stage, vertically operated centrifugal pumps, in which at least two pump stages are arranged in a pump housing between a foot part and a head part of the pump housing, which are surrounded on the outside by a wall part connecting the foot part to the head part. A suction and a pressure port of the centrifugal pump are formed on the foot part. The liquid to be pumped by the centrifugal pump first passes through the suction port to a first pump stage and from there to the last pump stage, from where it is returned to the foot section and is led out of the centrifugal pump via the pressure port. The pump shaft of the centrifugal pump, which connects the impellers of the individual pump stages, is sealingly led out through the head part, where it is motionally coupled to the motor shaft of an electric drive motor mounted axially spaced from the head part on a motor chair typically made of cast steel. In the known centrifugal pumps, the motor chair is either an integral part of the head part or detachably attached to the head part, with rod bolts connecting the motor chair to the foot part. A typical representative of these pump types is, for example, in WO 2014/187648 shown.

The object of the invention is to provide a multi-stage centrifugal pump of the type described above, which has a simplified structure and a more attractive appearance compared to the known pumps.

This object is achieved by a multi-stage centrifugal pump with the features specified in claim 1. Advantageous further developments of this centrifugal pump result from the subclaims, the following description and the drawing. The features specified in the subclaims and the description can further develop the solution according to the invention according to claim 1, either individually or in a suitable combination with one another.

The multi-stage centrifugal pump according to the invention has a foot part and a head part, between which at least two pump stages, each with an impeller, are arranged. This centrifugal pump is preferably a vertically operated centrifugal pump, that is to say a centrifugal pump which is operated standing on the base part with vertically oriented impeller axes, but it should be pointed out that the centrifugal pump according to the invention is also one in any other Location operated centrifugal pump can act. The pump stages of the centrifugal pump are surrounded on the outside by a wall part which connects the foot part to the head part and thus forms a pump housing together with the foot part and the head part. In addition, the centrifugal pump according to the invention has a motor chair adjoining the head part for receiving an electric motor provided for operating the centrifugal pump. The electric motor is mounted on the motor chair at a distance from the head part in the direction of a central axis of the centrifugal pump, one end protruding from the head part and one with the Impellers of the pump stages connected pump shaft in the area of the motor chair can be coupled to a motor shaft of the electric motor.

Compared to the known multistage centrifugal pumps of the type in question, the centrifugal pump according to the invention is characterized in that the wall part of the pump housing extends in the axial direction, that is to say in the direction of the central axis of the centrifugal pump or in the direction of its impeller axes, beyond the head part and with it Motor chair is connected to accommodate the electric motor. In contrast to the conventional centrifugal pumps, in the centrifugal pump according to the invention it is no longer the head part but instead the wall part surrounding the pump stages of the centrifugal pump that surrounds the motor chair. This considerably increases the freedom of design with regard to the design of the centrifugal pump. This applies, for example, to the design of the head part, which can be simplified in terms of construction and manufacturing technology due to its static load, which is significantly lower than that of the known centrifugal pumps. The rod bolts previously used to connect the motor chair to the foot part are no longer required in the centrifugal pump according to the invention. With regard to the overall appearance of the centrifugal pump, there are completely new possibilities, so that the centrifugal pump can be made visually more appealing.

The wall part is preferably formed by a tube, in which the head part is incorporated, in a constructionally and technically simple manner. The pipe can either be a pipe with a welded seam or a seamless pipe. In the latter case, the tube can be produced, for example, by deep drawing, as a result of which the wall thickness of the wall part can be easily determined. Regardless of the design of the tube, it is expediently connected at one end to the foot part in a pressure-tight manner. In a section of the tube adjoining the other end of the tube, the head part is inserted at a distance from this end and is likewise connected to the tube in a pressure-tight manner. The head part is preferably welded into the tube in this position. In this case, the welded connection of the head part and the tube can be provided within the tube or the welded connection can be made from the outside of the tube.

The motor chair preferably has an annular flange which is arranged at the end of the section of the wall part which extends beyond the head part. The ring flange, like the entire motor chair, is advantageously an aluminum injection molded part. The radial dimensions of the ring flange are preferably such that the outer circumference of the ring flange is aligned with the outer circumference of the wall part, so that the ring flange only extends radially into the clearance profile or in the direction of the interior of the wall part, but does not protrude on the outside beyond the outer circumference of the wall part .

The ring flange is further advantageously of shoulder-shaped design, it having a section engaging in the interior of the wall part and a section resting on the end of the wall part. Here, the outer diameter of the portion engaging in the interior of the wall part expediently corresponds to the inner diameter of the wall part, so that the wall part at its free end facing away from the foot part can be supported in the radial direction on the portion engaging in the interior of the wall part, which the Motor seat forming section of the wall part gives increased stability.

The ring flange advantageously forms the entire motor chair. In this context, an embodiment is preferred for which the ring flange is designed for fastening the electric motor. The electric motor is mounted on the flat side of the ring flange facing away from the foot part. The electric motor is advantageously fastened to the ring flange in the region of the ring flange which extends into the clearance profile of the wall part, where the fastening means on the ring flange side for fastening the electric motor are preferably arranged on the ring flange. These are preferably through holes which serve to receive screws with which the electric motor is screwed to the ring flange.

According to a further preferred embodiment of the centrifugal pump according to the invention, the ring flange is designed for fastening different electric motors. In this context, it can advantageously be provided that a plurality of through holes are formed on the ring flange at a first radial distance from a central axis of the ring flange in series over the circumference of the ring flange for producing a screw connection with a counter flange of a first electric motor and in at least one of them radial distance of these through holes deviating second radial distance distributed in series over the circumference of the ring flange further through holes are provided for producing a screw connection with a counter flange of a second electric motor.

In an alternative, advantageous embodiment to a ring flange which forms the motor chair directly, an attachment projecting in the axial direction can be arranged on the ring flange to form the motor chair, and a fastening flange for the electric motor is arranged on the end facing away from the ring flange. This configuration proves to be advantageous, for example, when larger electric motors are used. In addition, the axially protruding attachment on the ring flange enables it to pass over the top of the centrifugal pump projecting section of the wall part comparatively short, which has a positive effect on the bending and torsional rigidity of this section. When using small electric motors, the fastening flange arranged on the end of the attachment facing away from the ring flange can be dimensioned such that it is arranged within the clearance profile of the wall part or, in the case of electric motors of a larger type or in the case of electric motors with a larger counter flange, to the fastening flange also radially via the Project the outer contour of the wall part.

At least one window is preferably formed on the section of the wall part which extends beyond the head part. This window is to be understood as a larger recess provided on the wall part, via which the interior of the wall part in the region of the section forming the motor chair is accessible for maintenance and repair purposes. The at least one window is thus integrated in the wall part. When dimensioning the window, it must be taken into account that the wall part has to bear the weight of an electric motor, i.e. the at least one window should, if possible, have no influence on the mechanical stability of the wall part and should therefore not be too large.

In addition, it must be taken into account that a mechanical weakening of the wall part caused by the at least one window can have an unfavorable effect on undesired natural frequency excitation of the wall part. To counteract this, it is advantageous to increase the rigidity of the wall part by taking suitable measures. A step aimed in this direction can consist in strengthening the wall thickness of the wall part in the section protruding beyond the head part compared to the wall thickness on the remaining wall part. As a further measure, it is also possible for a cover plate of the window to be load-bearing Function. In addition, the mechanical structure can also be stabilized in that corresponding mechanical deformations are formed in the wall part.

Particularly advantageously, two windows are formed on the section of the wall part extending beyond the head part, which are arranged in such a way that a shaft seal sealing the pump shaft from the head part and at least one vent valve of the centrifugal pump arranged on the head part are accessible via the windows. In the centrifugal pump according to the invention, two vent valves are preferably provided on the head part, which are arranged together in a plane running through the central axis of the centrifugal pump and its head part on two sides facing away from the central axis. In this case, the two windows formed on the wall part are expediently arranged diametrically opposite one another radially on the outside of the vent valves.

The head part of the centrifugal pump according to the invention is preferably designed as a deep-drawn part made of preferably stainless steel. Accordingly, a comparatively thin-walled sheet of steel and preferably of stainless steel can be used to produce the head part, which is converted into a preferably curved shape by means of a deep-drawing process. Compared to the head parts previously made from cast steel, the head part of the centrifugal pump according to the invention thus has a significantly lower weight, which typically also has a positive effect on the total weight of the centrifugal pump. When using stainless steel, the corrosion resistance of the headboard also proves to be advantageous.

The wall part is expediently detachably connected to the foot part for maintenance, cleaning or repair purposes. In this Connection is preferably provided that the wall part is clamped to the foot part with a clamping ring. Here, a section of the foot part preferably engages in an end section of the wall part facing away from the head part and the motor chair, the clamping ring surrounding the wall part radially on the outside pressing the wall part against the foot part. For the pressure-tight sealing of the wall part with respect to the foot part, a seal is expediently arranged between the wall part and the foot part.

The clamping ring used to connect the wall part to the foot part is preferably divided into a plurality of ring segments in the circumferential direction. Accordingly, the clamping ring has a plurality of ring segments, which are arranged next to one another in the circumferential direction and connected to one another, form the clamping ring. This split configuration of the clamping ring is advantageous in that it enables a simple arrangement of the clamping ring on the outside of the wall part and ensures uniform power transmission from the clamping ring to the wall part.

The individual ring segments of the clamping ring are preferably designed in such a way that a recess directly adjacent to the respective end of the ring segment is formed at their two circumferential ends, a first recess being formed on a first flat side of the ring segment oriented perpendicular to the central axis of the clamping ring, and the another recess is formed on a second flat side facing away from the first flat side and oriented parallel to the first flat side. Accordingly, when the ring segments are mounted on the wall part, one recess is directed in the direction of the head part, while the other recess faces the foot part. In the area of the recesses, the interconnected ring segments of the Clamping ring arranged to overlap each other in the axial and circumferential direction of the clamping ring.

The individual ring segments of the clamping ring are preferably not only connected to one another but also to the foot part. According to a further advantageous embodiment of the centrifugal pump according to the invention, it is provided that the ring segments of the clamping ring are screwed together with the foot part to produce a connection. For this purpose, through holes are formed on the two recesses of the ring segments in the axial direction of the clamping ring, which are arranged such that in the assembled state of the clamping ring and the then overlapping recesses of the ring segments, the through holes formed on the overlapping recesses are aligned with one another. A head screw is guided through the common through hole thus formed, which is screwed into a threaded blind hole formed on the foot part.

Fig. 1

eine vertikale mehrstufige Kreiselpumpe in einer Seitenansicht,

Fig. 2

einen Schnitt entlang der Schnittlinie II-II in Fig. 1,

Fig. 3

die Kreiselpumpe nach den Fig. 1 und 2 in einer Draufsicht,

Fig. 4

in perspektivischer Darstellung einen Endabschnitt der Kreiselpumpe nach den Fig. 1 - 3 im Bereich eines Kopfteils der Kreiselpumpe,

Fig. 5

eine Ansicht in Richtung V-V in Fig. 4,

Fig. 6

in perspektivischer Darstellung einen Endabschnitt der Kreiselpumpe nach den Fig. 1 - 3 im Bereich eines Fußteils der Kreiselpumpe,

Fig. 7

den Endabschnitt nach Fig. 6 in einer Seitenansicht,

Fig. 8

ein Ringsegment eines Klemmrings in einer Draufsicht,

Fig. 9

das Ringsegment nach Fig. 8 in perspektivischer Darstellung,

Fig. 10

eine Einzelheit A aus Fig. 2,

Fig. 11

in perspektivischer Darstellung ein Pumpenaggregat mit einer Kreiselpumpe nach den Fig. 1 - 3 und einem Elektromotor zum Antrieb der Kreiselpumpe,

Fig. 12

in einem Längsschnitt einen Endabschnitt einer Kreiselpumpe gemäß einer zweiten Ausgestaltung im Bereich eines Kopfteils der Kreiselpumpe,

Fig. 13

eine Einzelheit aus Fig. 12 in perspektivischer Darstellung,

Fig. 14

in einem Längsschnitt einen Endabschnitt einer Kreiselpumpe gemäß einer dritten Ausgestaltung im Bereich eines Kopfteils der Kreiselpumpe, und

Fig. 15

in einer Seitenansicht einen Endabschnitt eines Pumpenaggregats mit einer Kreiselpumpe gemäß einer vierten Ausgestaltung.

The invention is explained in more detail below on the basis of exemplary embodiments illustrated in the drawing. The drawing shows schematically simplified and in different scales:

Fig. 1

a vertical multi-stage centrifugal pump in a side view,

Fig. 2

a section along the section line II-II in Fig. 1 ,

Fig. 3

the centrifugal pump after the Fig. 1 and 2nd in a top view,

Fig. 4

in perspective an end portion of the centrifugal pump according to the 1 - 3 in the area of a head part of the centrifugal pump,

Fig. 5

a view towards VV in Fig. 4 ,

Fig. 6

in perspective an end portion of the centrifugal pump according to the 1 - 3 in the area of a foot part of the centrifugal pump,

Fig. 7

the end section after Fig. 6 in a side view,

Fig. 8

a ring segment of a clamping ring in a plan view,

Fig. 9

the ring segment after Fig. 8 in perspective,

Fig. 10

a detail A from Fig. 2 ,

Fig. 11

in perspective a pump unit with a centrifugal pump according to the 1 - 3 and an electric motor to drive the centrifugal pump,

Fig. 12

in a longitudinal section an end section of a centrifugal pump according to a second embodiment in the region of a head part of the centrifugal pump,

Fig. 13

a detail Fig. 12 in perspective,

Fig. 14

in a longitudinal section an end section of a centrifugal pump according to a third embodiment in the region of a head part of the centrifugal pump, and

Fig. 15

in a side view an end portion of a pump unit with a centrifugal pump according to a fourth embodiment.

The in the 1 - 11 The multistage centrifugal pump shown has a foot part 2. This foot part 2 is equipped with two connecting flanges 4 and 6. Of these connection flanges 4 and 6, the connection flange 4 forms a suction connection and the connection flange 6 a pressure connection of the centrifugal pump.

The connecting flange 4 forming the suction nozzle surrounds a suction channel 8, which opens within a suction space formed in the foot part 2, to which the suction mouth of an impeller 10 of a first pump stage of the centrifugal pump connects, which is formed by the impeller 10 and a housing 12 surrounding it. In total, the centrifugal pump has five pump stages consisting of an impeller 10 and a housing 12. These pump stages are arranged vertically one above the other, the impellers 10 of these pump stages being seated on a common pump shaft which is led out of a pump housing of the centrifugal pump on the upper side thereof at a head part 14 spaced in the vertical direction from the foot part 2. This pump shaft is not relevant to the invention and is therefore omitted from the drawing for reasons of better clarity.

In addition to the foot part 2 and the head part 14, the pump housing of the centrifugal pump is also formed by a wall part 16 which connects the foot part 2 to the head part 14 and surrounds the pump stages of the centrifugal pumps at a radial distance. As a wall part 16 is used in the present embodiment, a stainless steel tube. Like the one in particular Fig. 1 , 4th and 11 can be seen, the wall part 16 has a section 18 which extends in the axial direction of the centrifugal pump beyond the head part 14. Thus, the head part 14 is integrated into the wall part 16 at a distance from the end of the wall part 16 facing away from the foot part 2, the head part 14 being connected to the wall part 16 in a pressure-tight manner by means of a weld. The welding is carried out on the inside of the wall part 16 by means of laser welding.

At the end of the section 18 of the wall part 16 facing away from the foot part 2, an annular flange 24 is arranged. The ring flange 24 forms a motor chair for an electric motor 20, a motor shaft of the electric motor 20 being connected via a coupling 22 to the pump shaft (not shown) in the region of the section 18 of the wall part 16.

Out Fig. 2 it can be seen that the annular flange 24 is of shoulder-shaped design and has a section 26 engaging in the interior of the wall part 16 and a section 28 resting on the end of the wall part 16. Here, the outer cross section of section 26 of ring flange 24 corresponds to the inner cross section of wall part 16 and the outer cross section of section 28 of ring flange 24 corresponds to the outer cross section of wall part 16.

The connection of the electric motor 20 to the ring flange 24 takes place via a screw connection. For this purpose, on the ring flange 24, such as in particular Fig. 4 can be seen, at the same radial distance from the center of the ring flange 24 four through holes 30 extending in the axial direction of the ring flange 24 are formed, which serve to receive the screws, by means of which a counter flange of the electric motor 20 is attached to the ring flange 24. In addition, four further axially directed through holes 32 are formed on the ring flange 24, which are arranged at the same radial distance from the center of the ring flange 24, the radial distance of the through holes 32 from the center of the ring flange 24 being less than the radial distance of the through holes 30 from the center of the ring flange 24. The through holes 32 are used to fasten an electric motor, the counter flange of which differs from the counter flange of the electric motor 20.

Two windows 34 are formed diametrically opposite one another on section 18 of wall part 16. The interior of section 18 of wall part 16 is accessible from outside wall part 16 via window 34. Thus, among other things, assembly, maintenance or repair work on the coupling 22 connecting the pump shaft to the motor shaft as well as on a shaft seal 36 sealing the pump shaft from the head part 14 and two vent valves 38 of the centrifugal pump arranged on the head part 14 can be carried out via the windows 34 .

On an upper side of the window 34 facing the annular flange 24, two recesses are formed, in each of which a tongue 40, which is directed into the interior of the wall part 16 and serves for releasably fastening the annular flange 24 to the wall part 16, engages. In a region of the tongue 40 covering the section 26 of the ring flange 24, a through hole 42 is formed in each case, which is used to receive a screw which is screwed into a threaded blind hole which is formed on the section 26 of the ring flange 24 and corresponds in position to the through hole 42 , whereby the annular flange 24 is fixed to the wall part 16.

The wall part 16 is widened radially at its end facing away from the head part 14, in that the wall part 16 merges there into a radially widened section 44 via a shoulder. A section 46 of the base part 2 engages in this enlarged section 44 of the wall part 16, which section forms part of the flow connection between the connecting flanges 4 and 6 and the pump housing (see Fig. 2 and 10th ). On the outer circumference of section 46 of foot part 2, an annular groove 48 is formed, which for receiving a sealing ring 50 (sealing wall part 16 from foot part 2) ( Fig. 2 ) serves.

The pressure-tight connection of the wall part 16 to the foot part 2 takes place via a clamping ring 52. This clamping ring 52 is circumferentially divided and has six identical ring segments 54, the structure of which is shown in FIG 8 and 9 becomes clear. The 8 and 9 it can be seen that at the two circumferential ends of the ring segments 54 there is in each case a recess 56 or 58 immediately adjacent to the relevant end. Here, the recess 56 is formed on a flat side 60 and the recess 58 on a flat side of the ring segment 54 facing away from the flat side 60. Adjacent to the flat side 60, the ring segments 54 also each have a shoulder 64, which in the assembled state of the ring segments 54 points in the direction of the center of the clamping ring 52. In the assembled state, the ring segments 54 overlap one another in the region of the recesses 56 and 58 formed on the ring segments 54, a section of a first ring segment 54 which is reduced in the region of the recess 56 in the axial direction of the clamping ring 52 and one in the region of the recess 58 likewise in the axial direction of the clamping ring 52 reduced portion of a second ring segment 54 contacted.

The ring segments 54 are connected to one another by means of a screw connection. To accommodate the screws 66 required for this purpose, through-holes 68 are formed on the ring segments 54 in the region of the recesses 56 and 58, which are aligned with one another when adjacent ring segments 54 overlap one another in the region of the recesses 56 and 58. The screws 66 are used not only to connect the ring segments 54 to one another but also to brace the clamping ring 52 on the outside of the wall part 16 Fig. 10 becomes clear. To clamp the clamping ring 52 on the outside of the wall part 16, the individual ring segments 54 of the clamping ring 52 are arranged on the outside of the wall part 16 in such a way that their shoulder 64 engages around a shoulder 70 forming a transition on the wall part 16 to its enlarged section 44 and come to bear on six projections 72 projecting radially on the base part 2, the through holes 68 formed on the overlapping sections of the ring segments 54 being aligned with threaded blind holes 74 formed on the projections 72. To clamp the clamping ring 52 on the outside of the wall part 16, the screws 66 guided through the through holes 68 of the ring segments 54 are screwed into the threaded blind holes 74.

The in the 12 and 13 Centrifugal pump shown differs from that in the 1 - 11 Centrifugal pump shown only with regard to the design of the wall part connecting the foot part 2 to the head part 14 and the design of the motor chair and its connection to the wall part. In the in the 12 and 13 Centrifugal pump shown extends a wall part 16 'to a lesser extent than the wall part 16 of the in the Figures 1-12 shown centrifugal pump over the head part, so that a section 18 'of the wall part 16' shorter than the section 18 of the wall part 16 of the in the Figures 1-12 centrifugal pump shown.

On that in the 12 and 13 Arranged at the upper end of the wall part 16 'is an annular flange 24' which engages with a section 26 'in the interior of the wall part 16' and rests with a section 28 'on the wall part 16'. The ring flange 24 'has a structure 76 on its flat side facing away from the head part 14. The structure 76 is formed by two webs 78 which are arranged opposite one another on the ring flange 24 and run obliquely on a central axis X of the centrifugal pump. Of the two webs 78 is in the 12 and 13 only one web 78 can be seen in each case.

At the end of the structure 76 facing away from the annular flange 24 ', a fastening flange 80 is arranged thereon. The fastening flange 80 is used to fasten an electric motor 20 which is screwed to the fastening flange 80 with a counter flange.

Together, the annular flange 24 ', the structure 76 and the fastening flange 80 thus form a motor chair for the electric motor 20, on this motor chair the coupling of the pump shaft arranged between the fastening flange 80 and the annular flange 24' with the drive shaft of the motor 20, which in the 12 and 13 is not shown, and the components, also not shown, on the head part 14 are easily accessible via the spaces between the webs 78 forming the structure 76.

The attachment of the motor chair in the 12 and 13 centrifugal pump is shown in particular Fig. 13 clear. To fasten the motor chair, two rectangular openings 82 are formed on the wall part 16 'diametrically opposite one another and just below the area in which the section 26' of the ring element 24 'engages in the interior of the wall part 16'. The openings 82 each serve to receive a fastening element 84. The fastening elements 84 each have a base body 86 with a rectangular cross-sectional contour corresponding to the openings 82, which engages from the outside of the wall part 16 'through the opening 82 into the interior of the wall part 16', and an end section 88 which extends over the cross-sectional contour of the base body 86 protrudes and comes to rest on the outside of the wall part 16 '. A threaded hole 90 extends through the base body 86 of the fastening elements 84 and is aligned in the installed position of the fastening element 84 on the wall part 16 ′ parallel to the central axis X of the centrifugal pump. Corresponding to the position of the threaded hole 90 in the installed position of the fastening elements 84 on the wall part 16 ', two through holes 92 are formed on the ring flange 24'. These through holes 92 each serve to receive a cap screw 94 which is screwed into the threaded hole 90 of the fastening element 84, whereby the motor chair is fixed to the wall part 16 '.

In the Fig. 14 Centrifugal pump shown corresponds essentially to that in the 12 and 13 centrifugal pump shown and differs from this only in terms of the attachment of the motor chair to the wall part 16 '. This attachment is carried out by a welded connection of the ring flange 24 'to the wall part 16 in the area in which the section 26' engages in the interior of the wall part 6 '.

In the Fig. 15 The centrifugal pump shown is based essentially on that in the 1 - 11 centrifugal pump shown and differs from the latter centrifugal pump only in terms of the design of the motor chair. This motor chair has an annular flange 24 ", which extends from the annular flange 24 in the 1 - 11 The centrifugal pump shown only differs with regard to the axial dimensions of section 28 ″. On the one facing away from wall part 16 A fastening flange 80 'is arranged on the flat side of section 28 ". The fastening flange 80' is designed for fastening electric motors 20 with a larger counter flange 96 and for this purpose extends radially beyond the outer circumference of the wall part 16 Area extending beyond the wall part 16, the mounting flange 80 'is supported on a plurality of stiffening ribs 98 which project radially on the outer circumference of the section 28 "of the ring flange 24".

Reference list

2nd

- foot section

4th

- connection flange

6

- connection flange

8th

- suction channel

10th

- Wheel

12th

- Casing

14

- headboard

16, 16 '

- wall part

18, 18 '

- Section

20

- electric motor

22

- clutch

24, 24 ', 24 "

- ring flange

26, 26 '

- Section

28, 28 ', 28 "

- Section

30th

- through hole

32

- through hole

34

- Window

36

- shaft seal

38

- vent valve

40

- Tongue

42

- through hole

44

- Section

46

- Section

48

- ring groove

50

- sealing ring

52

- clamping ring

54

- ring segment

56

- recess

58

- recess

60

- flat side

62

- flat side

64

- Paragraph

66

- screw

68

- through hole

70

- Paragraph

72

- Head Start

74

- threaded blind hole

76

- Construction

78

- dock

80, 80 '

- mounting flange

82

- breakthrough

84

- fastener

86

- Basic body

88

- end section

90

- threaded hole

92

- through hole

94

- cap screw

96

- counter flange

98

- stiffening rib

A

- detail

X

- central axis

Claims (13)

1. A multi-stage centrifugal pump with a foot part (2), a head part (14), a wall part (16, 16') which connects the foot part (2) to the head part (14) and surrounds the pump stages at the outer periphery, and with a motor stool connecting to the head part (14) and for receiving an electric motor (20) provided for the drive of the centrifugal pump, characterised in that the wall part (16, 16') projects in the axial direction beyond the head part (14) and is connected to the motor stool.
2. A centrifugal pump according to claim 1, characterised in that the wall part (16, 16') is formed by a tube, in which the head part (14) is integrated, preferably welded.
3. A centrifugal pump according to one of the preceding claims, characterised in that the motor stool comprises an annular flange (24, 24') which is arranged at the end of the section (18, 18') of the wall part (16, 16') which extends beyond the head part (14).
4. A centrifugal pump according to claim 3, characterised in that the annular flange (24, 24') is designed in a shouldered manner and comprises a section (26, 26') which engages into the inside of the wall part (16, 16'), and a section (28, 28') which lies on the end of the wall part (16, 16').
5. A centrifugal pump according to one of the claims 3 or 4, characterised in that the annular flange (24) is designed for fastening the electric motor (20).
6. A centrifugal pump according to claim 5, characterised in that the annular flange (24) is designed for fastening different electric motors (20).
7. A centrifugal pump according to one of the claims 3 or 4, characterised in that an attachment (76) which projects in the axial direction and at whose end which is away from the annular flange (24') a fastening flange (80) for the electric motor (20) is arranged, is formed on the annular flange (24').
8. A centrifugal pump according to one of the preceding claims, characterised in that at least one window (34) is formed on the section (18) of the wall part (16) which extends beyond the head part (14).
9. A centrifugal pump according to one of the preceding claims, characterised in that two windows (24) are formed on the section (18) of the wall part (16) which extends beyond the head part (14), said windows being arranged in a manner such that a shaft seal (36) sealing the pump shaft with respect to the head part (14), as well as at least one bleed valve (38) of the centrifugal pump which is arranged on the head part (14), are accessible via the windows (34).
10. A centrifugal pump according to one of the preceding claims, characterised in that the head part (14) is designed as a deep-drawn part of preferably stainless steel.
11. A centrifugal pump according to one of the preceding claims, characterised in that the wall part (16, 16') is clamped on the foot part (2) by a clamping ring (52).
12. A centrifugal pump according to claim 11, characterised in that the clamping ring (52) in the peripheral direction is designed divided into several ring segments (54).
13. A centrifugal pump according to claim 12, characterised in that the ring segments (54) of the clamping ring (52) are connected to the foot part (2) amid the creation of a connection to one another.

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