ES2989660T3 - Pump for pumping a fluid - Google Patents

Abstract

The invention relates to a pump for transporting a fluid, comprising a housing (4) and a pump shaft (2) arranged inside the housing (4) and rotatable about an axis (A), with an impeller (34) arranged on the pump shaft (2) in a rotationally fixed manner to act on the fluid, the pump (1) further comprising a pump inlet (7) for supplying the fluid to the interior and a pump outlet (6) for discharging the fluid from the interior, one end of the housing (4) comprising a cover (5, 51, 52), and the pump (1) comprising a clamping device (10) for fixing the cover (5, 51, 52) to the housing (4), the clamping device (10) comprising a clamping element (11) and a clamping means (12) which can be arranged in a hole (13) of the clamping element (11), the clamping element (11) comprising a first contact surface. (111) and a second contact surface (112). The clamping means (12) is arranged to be movable relative to the clamping element (11) along a clamping axis (X) such that the clamping element (11) is clamped between the housing (4) and the cover (5, 51, 52) by interaction with the clamping means (12) when the cover is in an installed state, wherein in the installed state a clamping force is exerted on the cover from the housing (4) via the first contact surface (111) to the second contact surface (112), such that the cover (5, 51, 52) is fixed to the housing (4) by the clamping force when installed. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Pump for pumping a fluid

The invention relates to a jacketed casing pump according to the general term of the independent claim.

Multistage pumps for transporting a fluid are used in many different industries, in particular for applications where high pressure must be generated. Important industrial sectors where multistage pumps are used are, for example, the oil and gas processing industry, the power generation industry, the chemical industry, the clean and waste water industry or the pulp and paper industry.

In the oil and gas processing industry, multistage pumps are designed, for example, to pump hydrocarbon fluids, for example to extract crude oil from the oil field or to transport oil/gas through pipelines or within refineries. Another application is the injection of a process fluid, in most cases water and especially seawater, into an oil reservoir. For such applications, these pumps are designed as (water) injection pumps that pump seawater at high pressure into a well leading to an underground zone of an oil reservoir.

For other applications, a multistage pump may be designed as a boiler feed pump for a power plant or as a booster pump, for example in a reverse osmosis process for desalination of water, to name just a few examples.

A multistage pump consists of several stages, each with an impeller, where all impellers are arranged one after the other on a common pump shaft. The pump shaft is driven to rotate around an axis, for example by an electric motor, so that all impellers rotate together around the axis.

Various designs of multistage pumps are known. A multistage pump can be designed as a vertical pump, i.e. the pump shaft extends in a vertical direction during pump operation, the vertical direction being the direction of gravity. A multistage pump can be configured as a horizontal pump, i.e. the pump shaft extends in a horizontal direction during pump operation, the vertical direction being the direction of gravity. Furthermore, a multistage pump can be configured as a radially split pump or an axially split pump. Other embodiments of multistage pumps are, for example, sectional or casing pumps.

Sectional pumps consist of several stage casings arranged one behind the other in the axial direction defined by the pump axis. The stage casings are fixed to each other with the help of tie rods that extend through all the stage casings. Most stage casings consist of a suction casing on the inlet side of the pump and a discharge casing on the outlet side of the pump. All stage casings together form the casing of the multistage pump.

Jacketed casing pumps also consist of a large number of stage casings, similar to sectional pumps. However, the stage casings are arranged within an outer casing (jacketed casing) surrounding the stage casings, so that this type of multistage pump is a double casing pump. The jacketed casing is closed at its axial ends by a cover, i.e. a suction cover or a discharge cover. It is also possible for the stage casings to be designed in such a way that together they form a cartridge which can be removed from the jacketed casing in its entirety.

In order to close the jacketed casing at the axial end with the cover, the jacketed casing and the cover are connected by a screw connection (or bolt connection). In this case, the cover and the jacketed casing have corresponding holes for connecting them to each other by means of a large number of screws and thus closing the jacketed casing with the cover. When the pump is in operation, the cover and thus the screw connection are exposed to high loads, since high pressure is generated inside the jacketed casing, which also acts on the cover and the screw connection. In addition, in the event of a pump failure, an upward hydraulic axial thrust can act on the cover. In this case, the pressure must be absorbed directly by the screw connection. This has a negative effect on the sealing behaviour of the cover / jacketed casing connection. The loads are transmitted exclusively via the screws of the screw connection, which can lead to deformations that have a negative effect on the sealing behaviour. This can lead to leaks in the jacketed casing. This can become a problem especially in the case of submersible pumps, as they are subjected to additional loads due to the water pressure.

Documents DE 102016205528 A1, US 2008/031732 A1 and US 4380405 A disclose pumps according to the state of the art.

Based on this state of the art, the aim of the invention is to provide a pump with a jacketed casing which avoids the disadvantageous effects known in the state of the art, in particular which allows a more compact and easy-to-assemble solution/design compared to a conventional screwed connection and in particular which is suitable for absorbing an axial thrust in the event of malfunction.

This task is solved by a bomb with the characteristics of independent claim.

The dependent claims refer to particularly advantageous embodiments of the invention.

The invention relates to a pump for transporting a fluid, comprising a jacketed casing and a pump shaft arranged inside the jacketed casing and rotatable about an axis. The pump shaft comprises an impeller arranged rotationally fixed thereon for acting on the fluid, wherein the pump further comprises a pump inlet for supplying the fluid to the interior and a pump outlet for discharging the fluid from the interior. One end, in particular an axial end, of the jacketed casing is closed with a cover. Furthermore, the pump comprises a clamping arrangement for fixing the cover to the jacketed casing, wherein the clamping arrangement comprises a clamping element and a clamping means which can be arranged in a hole of the clamping element. In this case, the clamping element comprises a first contact surface and a second contact surface.

The clamping arrangement according to the invention can be used to secure the cover in the axial direction, in particular in the event of a failure, by directing a hydraulic thrust upwards into the housing via the clamping element. In principle, however, the cover can also be connected to the housing via the clamping element, in particular fixed to the jacketed housing (e.g. to close the jacketed housing with the cover).

The pump according to the invention is characterized in that the clamping means are arranged to be movable relative to the clamping element along a clamping axis such that the clamping element is clamped between the jacketed housing and the cover by interaction with the clamping means (arranged in the hole of the clamping element) in an installed state of the cover, wherein, in the mounted state, a clamping force is exerted on the cover from the jacketed housing via the first contact surface to the second contact surface (or, in the mounted state, the clamping force is also exerted on the jacketed housing from the cover via the second contact surface to the first contact surface), so that, in the mounted state, the cover is fixed to the jacketed housing by the clamping force (in particular, fixed in an axial direction). In this way, in the event of a pump failure, the cover can be fixed in the direction of the resulting hydraulic thrust.

The installed state is therefore the state in which the cover is fixed to the jacketed housing, where the clamping force is generated in particular by the clamping element which is clamped between the cover and the jacketed housing.

Since the clamping element is clamped between the casing and the cover when the latter is installed, the (operating) loads are no longer (exclusively) transmitted via the screwed connections, but via the clamping element, which is preferably clamped in a force-tight and tight manner. The result is a favourable flow of force from the cover to the casing via the clamping element.

The pump according to the invention with the clamping arrangement according to the invention thus ensures in particular that the pressure on the cover and the resulting forces do not have to be absorbed by a screw connection, but are largely transmitted to the jacketed housing via the clamping element, which leads to a considerable relief of the clamping means. The clamping means is thus only subjected to a small part of the clamping forces and moments to be transmitted. In contrast to the prior art, the clamping means is not the main component subjected to load. The clamping means fixes the clamping element (after a clamping process) in its position (in the assembled state). Compared to the prior art, the clamping means can be significantly smaller (shorter and/or smaller diameter clamping means).

It is a particularly preferred embodiment of the invention if the pump comprises a plurality of clamping arrangements. In particular, the plurality of clamping arrangements can be understood in the sense of at least two clamping arrangements. However, 20 (or another plurality of) clamping arrangements could also be used, for example. In practice, both axial ends of the pump can also be closed with a cover. The suction side with a suction cover and the discharge side with a discharge cover. The suction cover is preferably held with a first plurality of clamping arrangements and the discharge cover with a second plurality of clamping arrangements.

The clamping arrangement according to the invention comprises a retaining element. In one embodiment, the retaining element is arranged between the clamping element and the jacketed housing in the assembled state such that the clamping force is exerted (or transmitted) from the jacketed housing via the retaining element to the first contact surface in the assembled state. In an alternative embodiment, the retaining element is arranged between the clamping element and the cover in the assembled state such that the clamping force is exerted on the cover by the retaining element via the second contact surface in the assembled state.

Among other things, the retaining element can simplify the fixing of the clamping arrangement to the cover and the jacketed housing.

In particular, the retaining element may comprise a clamping hole. In the assembled state, the clamping means are arranged in the clamping hole such that the clamping element is clamped between the jacketed housing and the cover via the clamping element. Thus, the clamping means is arranged both in the hole of the clamping means and in the clamping hole of the retaining element. When the clamping element is clamped in the assembled state with the clamping means, the clamping element is arranged relative to the retaining element (guided towards the retaining element) such that it is clamped via the retaining element.

In practice, the retaining element may also include an additional hole. In the assembled state, a retaining means is arranged in the additional hole such that the retaining element is fixed to the jacketed housing or the cover. The retaining means may be, for example, a screw, a pin or a bolt, which is stretched/rotated in the additional hole to position the retaining element on the jacketed housing or the cover. This facilitates the fixing of the cover (transfer to the installed state) and also enables a more stable clamping arrangement.

In a particularly preferred embodiment, the clamping element may be designed as a wedge-shaped clamping element, whereby in particular the first contact surface may be a conical first contact surface and the second contact surface may be a second annular (or ring-segment-shaped) contact surface. In particular, by annular it may be understood that the contact surface corresponds to the surface of an annular section/ring segment.

In order to simplify the location of the holding arrangement, the jacketed casing or the cover may comprise a protrusion where the holding arrangement is held/arranged between the jacketed casing and the cover in the assembled state. If the pump comprises a plurality of holding means, the cover or the jacketed casing preferably comprises a plurality of protrusions or a groove where the holding arrangements are held between the jacketed casing and the cover in the assembled state.

It is not necessary that the cover be fixed to the jacketed housing solely by the clamping force of the clamping arrangement. In order to enable a better fixing of the cover to the jacketed housing, the latter may comprise a projection, wherein the cover is arranged on a projection such that the cover is supported by the projection in an axial direction of the axis. While the cover is supported in the axial direction by the projection, the cover is supported in a direction opposite to the axial direction by the clamping arrangement, in particular a plurality of clamping arrangements, so that the cover is held in the axial direction and in the direction opposite to the axial direction. For this purpose, the cover may in particular comprise a shoulder with which the cover is subsequently arranged on the projection. Both the projection and the shoulder may be circumferential, so that the projection extends along an inner circumference of the jacketed housing and the shoulder extends along a, in particular outer, circumference of the cover.

Alternatively, a plurality of holding means could also be arranged on both sides of the lid (with reference to the axis or axial direction) for holding the lid in the axial direction and in the direction opposite to the axial direction (and thus for holding the lid in the assembled state). Both sides therefore refer to one side of the lid facing inwards and to the opposite side of the lid facing outwards.

In particular, the clamping arrangement acts as a thrust transmission device that transmits an upward hydraulic axial thrust (hydraulic axial thrust that pulls the cover inwards in the event of a (pump) failure) from the cover to the jacketed casing.

As already mentioned above, the pump preferably comprises a plurality of clamping means. In particular, the clamping arrangements are designed as ring-shaped segments. In the assembled state, these ring-shaped segments can be arranged at a uniform distance from one another along the circumference of the cover. The ring-shaped segments can be arranged in the protrusions or in the circumferential groove.

In practice, the clamping means may be designed as a clamping screw. In this case, the clamping screw is arranged in the hole of the clamping element. The hole comprises a thread corresponding to a screw thread of the clamping screw, so that the clamping screw can be moved along the clamping axis by rotation in the hole (around the clamping axis) such that the clamping element can be clamped between the jacketed housing and the cover by interacting with the clamping screw in the mounted state of the cover. As the rotation causes the clamping screw to move relative to the clamping element, the clamping element can be clamped between the cover and the jacketed housing. Tensioning is achieved, for example, by pressing one end of the screw against a surface of the cover (or the jacketed housing), whereby the force required for tensioning is transmitted to the clamping element. Alternatively, the force required for tightening may be exerted on the clamping element by placing the clamping screw into the clamping hole of the retaining element and guiding the clamping element towards the retaining element by rotating the clamping screw, thereby clamping it to the retaining element.

The thread settling due to relaxation, which usually occurs with the main load-bearing bolted connections of the prior art, is no longer relevant due to the arrangement according to the invention. The clamping means can also be designed as a clamping pin or a clamping bolt.

In a particularly preferred embodiment, the clamping element is designed as an annular wedge (wedge-shaped clamping element adapted to the round shape of the cover), especially if the clamping arrangement is designed as an annular segment and the clamping screw is guided through the hole of the annular wedge. As already mentioned, the pump preferably comprises a plurality of clamping arrangements, so that the annular wedges are clamped in the radial and axial direction in the protrusions or in the (annular) groove by means of the clamping screws and thus fix the cover. The cover preferably comprises flat contact surfaces in the groove/protrusions, against which the clamping elements with a wedge surface can bear (or bear in the assembled state).

In practice, the pump may be configured as a multistage pump. The multistage pump comprises a plurality of stages arranged in series with respect to the shaft, wherein the plurality of stages comprises at least a first stage and a last stage, wherein each stage has a stage casing and an impeller for acting on the fluid, and each impeller is rotatably fixed on the shaft of the pump. In particular, the pump may also be a submersible pump and/or a multiphase pump. In particular, the pump is preferably a jacketed pump.

The invention will now be explained in more detail with reference to the drawings.

The drawings show:

Fig. 1a a schematic cross-sectional view of an embodiment of a multistage pump according to the invention in a section along an axis;

Fig. 1b the embodiment according to Fig. 1a in a cross section perpendicular to the axial direction along the section line ll-ll in Fig. 1a;

Fig. 2a a schematic cross-sectional view of a clamping arrangement according to the invention with a clamping element and a clamping hole;

Fig. 2b a schematic cross-sectional view of an embodiment not in accordance with the invention;

Fig. 2c a schematic cross-sectional view of a clamping arrangement according to the invention with a retaining element;

Fig. 3a a schematic three-dimensional view of a clamping arrangement according to the invention with a retaining element and a clamping hole;

Fig. 3b another schematic three-dimensional view of the clamping arrangement according to the invention shown in Fig. 3a;

Fig. 4a a schematic cross-sectional view of a section of an embodiment of a multistage pump according to the invention in a section along an axis;

Fig. 4a a schematic cross-sectional view of a partial section of Fig. 4a.

Fig. 1a shows a schematic cross section of an embodiment of a multistage pump according to the invention, which is labeled in its entirety with the reference numeral 1. The multistage pump 1 is designed as a centrifugal pump for transporting a liquid from a pump inlet 7 to a pump outlet 6.

In the following description of a preferred embodiment of the multistage pump 1 according to the invention, a configuration is described by way of example, in which the multistage pump 1 is designed as a horizontal pump with a jacketed casing with a multistage casing, i.e. as a double-casing pump. The multistage pump can be designed, for example, as a pump 1 of the type BB5.

It is understood that the invention is not limited to such embodiments. For example, the multistage pump may be designed as a vertical multiphase pump.

The multistage pump 1 is composed of a jacketed casing 4 and a plurality of stages 3, each of which has an impeller 34 for pressurizing the liquid. All the impellers 34 are arranged one after the other on a pump shaft 2, which is designed to rotate about an axis A. The pump shaft 2 extends centrally through the jacketed casing 4 and is supported by radial bearings (not shown) and at least one axial bearing (not shown). Furthermore, shaft seals (not shown), for example mechanical seals, are provided in a manner known in the art. The shaft seals prevent liquid from escaping along the pump shaft 2 from the inside 8 of the jacketed casing 4 to the outside.

The A-axis defines an axial direction (as well as a direction opposite to the axial direction), so the A-axis is defined by the longitudinal axis of the pump shaft 2, i.e. the axis of rotation around which the pump shaft 2 rotates during operation. A direction perpendicular to the A-axis is called the “radial direction”. The term “axial” is used with the general meaning of “in the axial direction” or “with respect to the axial direction”. Similarly, the term “radial” is used with the common meaning of “in the radial direction” or “with respect to the radial direction”.

All impellers 34 are mounted on the pump shaft 2 in a rotationally fixed manner. The pump shaft 2 is driven by a drive unit (not shown), for example an electric motor. In the embodiment shown in Fig. 1a, the drive unit is arranged outside the jacketed housing 4 and coupled to the pump shaft 2 in a known manner. In other embodiments, the drive unit may be arranged inside the jacketed housing 4.

Fig. 1a shows the multistage pump 1 in a schematic cross-sectional view in a cut along the axis A. For better understanding, Fig. 1b shows the multistage pump 1 in a cross section perpendicular to the axis A along the sectional line ll-ll in Fig. 1a.

The jacketed housing 4 is closed by a cover, in particular by two covers. In the embodiment according to Fig. 1a, the jacketed housing is closed at its first axial end by a suction cover 51 and, at its second axial end, by a pressure cover 52. The suction cover 51 and the pressure cover 52 are connected to the housing 4 via a fastening means 10 according to the invention, which is arranged on a protrusion 18. The suction cover 51 and the pressure cover 52 are supported by a projection 20, whereby the suction cover 51 and the pressure cover 52 are fixed to the jacketed housing via the fastening means 10. The pump is thus installed.

The pump shaft 2 passes centrally through the suction cover 51 and the pressure cover 52. The casing 4 is secured between the suction cover 51 and the pressure cover 52. The casing 4 is tubular and is not secured to the pump shaft. The casing 4 is tubular and extends coaxially to the pump shaft 2 from the first axial end to the second axial end. Furthermore, the jacketed casing 4 is designed to accommodate the plurality of stages 3, such that the plurality of stages 3 are enclosed in the jacketed casing 2.

Of course, the housing does not have to be closed with two covers. One axial end of the pump can also be part of the housing, so that only the other axial end is closed with a cover.

The multistage pump 1 has the plurality of stages 3, comprising at least a first stage 31 and a last stage 33. The plurality of stages 3 may further comprise one or more intermediate stages 32. All intermediate stages 32 are arranged, with respect to the axis A, between the first stage 31 and the last stage 33. All stages 31, 32, 33 are arranged one after another in the interior 8 of the jacketed housing 4, so that the jacketed housing 4 encloses all stages 31, 32, 33. The first stage 31 is located next to the pump inlet 7 near the suction cover 51 and receives the low-pressure liquid from the pump inlet 7. The last stage 33 is located next to the outlet cover 52 and discharges the high-pressure liquid through the pump outlet 6. The liquid flow through the multistage pump 1 is shown in Fig. 1a by the solid line arrows without reference numbers.

In the embodiment shown in Fig. 1a, the multistage pump 1 comprises three intermediate stages 32, whereby the multistage pump 1 has five stages 31, 32, 33. It should be understood that the number of five stages 31, 32, 33 is only an example. In other embodiments, the multistage pump may comprise less than five stages, for example only two stages, i.e. there is no intermediate stage. In other embodiments, the multistage pump may comprise more than five stages, for example eight stages.

Each stage 31, 32, 33 of the plurality of stages 3 comprises a stage housing 30, an impeller 34 for pressurizing the liquid and a diffuser 9 configured to surround the impeller 34 and to receive the liquid from the impeller 34. The diffuser 9 of the last stage 33 is configured such that it simultaneously forms the stage housing 30 of the last stage 33.

The stage housings 30 are arranged in series with respect to the axis A.

The stage housing 30 of the first stage 31 abuts against a stationary part 41 of the multi-stage pump 1, the stationary part 41 being stationary relative to the housing 4. Each subsequent stage housing 30 abuts the respective preceding stage housing 30. All stage housings 30 thus form an inner pump housing, which is also called a cartridge.

The stage housings 30 are fixed to each other by a plurality of tie rods 42. Each tie rod 43 extends along axis A parallel to the axis of pump 2 and through all of the stage housings 30. The tie rods 42 are tensioned by means of turnbuckles 43 in a manner known in the prior art.

All of the impellers 34 are configured as radial impellers 34 with a plurality of impeller vanes that divert a fluid flow from a generally axial direction to the radial direction.

All diffusers 9 are designed as radial diffusers 9 and arranged such that they surround the respective impeller 34 radially outward. Behind each diffuser 9 of the first stage 31 and all intermediate stages 32, a plurality of guide channels 91 are provided in each case for deflecting the generally radial flow of the fluid in the axial direction and guiding the fluid from the respective diffuser 9 to the suction side of the impeller 34 of the next stage. Preferably, the guide channels 91 are delimited by guide vanes, which may be curved to gently deflect the fluid. The diffuser 9 of the last stage 33 is designed such that it guides the fluid towards the outlet 6 of the pump.

As can be seen in Fig. 1b, this embodiment of the multi-stage pump 1 comprises a plurality of holding arrangements 10, namely three holding arrangements 10 per cover 5, 51, 52, each holding arrangement 10 being arranged on a protrusion 18 of the cover 5 (suction cover 51 and/or discharge cover 52).

These clamping arrangements 10 are arranged at a uniform distance from each other along a circumference of the cover 5.

Fig. 2a shows a schematic cross-sectional view of the clamping arrangement 10 according to the invention with a retaining element 14 and a clamping hole 16 in the assembled state.

The clamping arrangement 10 comprises a clamping element 11 and a clamping means 12 arranged in a hole 13 of the clamping element 11. The clamping means 12 is designed as a clamping screw 12 and the clamping element 11 is designed as a wedge-shaped clamping element 11, wherein the first contact surface 111 is a conical first contact surface 111 and the second contact surface 112 is a second annular contact surface 112.

In the assembled state, the clamping screw 12 is arranged in the clamping hole 16 of the retaining element 14 such that the retaining element 11 is clamped between the housing 5 and the cover 4 via the retaining element 14. For this purpose, the clamping screw 12 is arranged both in the clamping hole 13 of the retaining element 11 and in the clamping hole 16 of the retaining element 14.

The retaining element 14 also comprises an additional hole 17. A retaining means 15, which is designed as a bolt 15, is arranged in the additional hole 17 such that the retaining element 14 is fixed to the jacketed housing 4.

The cover 5 comprises a protrusion 18 or a groove 18, in which the holding element 11 is arranged (at least partially).

In order to allow a better fixing of the cover 5 to the jacketed housing 4, the jacketed housing 4 comprises a projection 20, wherein the cover 5 is arranged with its shoulder 22 on the projection 20 such that the cover 5 is supported in the axial direction by the projection 20. While the cover 5 is supported in the axial direction of the axis A by the projection 20, the cover is supported in a direction opposite to the axial direction by the clamping arrangement 10, in particular a plurality of clamping arrangements, such that the cover 5 is secured in the axial direction and in the direction opposite to the axial direction (and is therefore in the mounted state).

When the clamping arrangement 10 is attached to the pump 1 (i.e. when it is brought into the installed state), the clamping arrangement 10 with the retaining element 14, where the clamping screw 12 is already arranged in the hole 13 and the clamping hole 16, is moved towards the cover 5 and the jacketed housing 4. Here, the clamping element 11 is inserted into the protrusion 18. The bolt 15 is then inserted through the additional hole 17 in the jacketed housing 4 to fix the clamping element 14. The clamping element 11 is then clamped by turning the clamping screw 12 in the hole 13. The hole 13 is provided with a thread (not shown) corresponding to the clamping screw 12, so that the clamping screw 12 rotates in the hole 13 about a tension axis X.

This causes the clamping element 11 to move in the direction of the retaining element 14, so that the clamping element 11 is clamped between the cover 5 and the jacketed housing 4 by interaction with the clamping screw 14 through the retaining element 14.

In the assembled state, a clamping force is therefore exerted from the jacketed housing 4 on the retaining element 14 via the first contact surface 111 to the second contact surface 112 on the cover 5 (or from the cover 5 via the second contact surface 112 to the first contact surface 111 via the retaining element 14 on the jacketed housing 4).

Fig. 2b shows a schematic cross-sectional view of an embodiment of the clamping arrangement 10 in the assembled state. The structure is basically analogous to the structure of the version according to Fig. 2a, but the clamping arrangement 10 only comprises the clamping element 11 and the clamping means 12, which is designed as a clamping screw 12. This embodiment without a clamping element is not in accordance with the invention.

When the clamping arrangement 10 is attached to the pump 1 (i.e. when it is put into the installed state), the clamping arrangement 10 moves towards the cover 5 and the jacketed housing 4. The clamping element 11 is inserted into the protrusion 18. For this purpose, the protrusion 18 can consist of a “larger part” for allowing the clamping element 11 to be inserted and a smaller part for fixing, so that the protrusion 18 and the clamping element 11 interact like a bayonet lock.

The clamping element 11 is then clamped by rotating the clamping screw 12 in the hole 13. The hole 13 comprises a thread (not shown) corresponding to the clamping screw 12, so that the clamping screw 12 rotates in the hole 13 about the clamping axis X. The clamping element 11 moves along the clamping axis X in the direction of the screw head 120 of the clamping screw 12, so that the clamping element 11 is clamped between the cover 5 and the jacketed housing 4 when interacting with the clamping screw 12, in the sense that the end of the clamping screw 12 opposite the screw head 120 abuts on a surface of the cover 5.

In the assembled state, the clamping force is exerted from the jacketed housing 4 via the first contact surface 111 to the second contact surface 112 of the cover 5 (or from the cover 5 via the second contact surface 112 to the first contact surface 111 of the housing 4).

Fig. 2c shows a schematic cross-sectional view of a clamping arrangement 10 according to the invention in the mounted state with the retaining element 14.

The structure is fundamentally analogous to the structure of the design shown in Fig. 2a, but the retaining element 14 does not include a clamping hole for the clamping element 11. The clamping means 12 is also designed as a clamping screw 12.

When the clamping arrangement 10 is attached to the pump 1 (i.e. when it is brought into the installed state), the clamping element 11 with the clamping screw 12 is inserted into the protrusion 18. The retaining element 14 is then brought into the corresponding position in the jacketed housing 4. The bolt 15 is then inserted through the additional hole 17 in the jacketed housing 4 to secure the retaining element 14. The clamping means 11 is clamped by turning the clamping screw 12 in the hole 13. The hole 13 comprises the thread corresponding to the clamping screw 12 (not shown), so that the clamping screw 12 rotates in the hole 13 about the clamping axis X. Here, the clamping element 11 moves in the direction of the screw head 120, so that the clamping element 11 is clamped between the cover 5 and the jacketed housing 4 by interacting with the clamping screw 14, in the sense that the end of the clamping screw 12 opposite the screw head 120 abuts on a surface of the cover 5.

In the assembled state, the clamping force is exerted from the jacketed housing 4 on the retaining element 14 via the first contact surface 111 to the second contact surface 112 on the cover 5 (or from the cover 5 via the second contact surface 112 to the first contact surface 111 via the retaining element 14 on the jacketed housing 4).

Fig. 3a shows a schematic three-dimensional view of a clamping arrangement 10 according to the invention with a retaining element 14 and a clamping hole 16. Fig. 3b shows another schematic three-dimensional view of the clamping arrangement 10 according to the invention shown in Fig. 3a.

The clamping arrangement 10 is designed as an annular segment 10.

The clamping element 11 is designed as an annular wedge 11 (wedge-shaped clamping element 11 adapted to a round shape of the lid) and the clamping screw 12 is guided through the hole 13 of the annular wedge 11. The first conical contact surface 111 is in contact with the retaining element 14, while the second annular contact surface 112 is arranged on the lid (not shown) in the assembled state.

This configuration is particularly preferable if a large number of clamping arrangements 10 are used.

Fig. 4a shows a schematic cross-sectional view of a section of an embodiment of a multi-stage pump 1 according to the invention in a section along the axis A. Fig. 4a shows a schematic cross-sectional view of a partial section of Fig. 4a.

The clamping arrangement 10 has a structure analogous to the clamping arrangement shown in Fig. 2a.

In order to enable a better fastening of the cover 5 to the jacketed housing 4, the jacketed housing 4 here also comprises the projection 20, whereby the cover 5 is arranged with the shoulder 22 on the projection 20 such that the cover 5 is supported by the projection 20 in the axial direction. While the cover 5 is supported in the axial direction of the axis A by the projection 20, the cover is supported in the direction opposite to the axial direction by the clamping arrangement 10, in particular a plurality of clamping arrangements, so that the cover 5 is secured in the axial direction and in the direction opposite to the axial direction. Furthermore, the cover 5 is additionally fixed to a cartridge 60 of the pump (in particular to a suction housing of the cartridge 60) by means of a plurality of bolts 21.

The clamping means 10 acts as a thrust transmission device which transmits the upward hydraulic axial thrust F (hydraulic axial thrust which pulls the cover 5 in the direction of the interior 8 in the event of a (pump) failure) from the cover 5 to the jacketed housing 4. The force is transmitted along the arrow F by the clamping element 11.

Thanks to the arrangement according to the invention, it can thus be avoided that the (operating) loads are no longer transmitted via screwed connections, but via the clamping element 11, which is preferably tightened in a forced and tight manner.

The clamping means 12 are only loaded with a small part of the forces and moments to be transmitted. In contrast to the prior art, the clamping means 12 is therefore not the main component subjected to load. The clamping means 12 fixes the clamping element 11 (after a clamping process) in its position (in the assembled state between the cover and the jacketed housing). Compared to the prior art, the clamping means 11 and all other screws, bolts or other fastening means used for the cover can therefore be significantly smaller (shorter and/or smaller diameter clamping means).

Claims (13)

1. A pump for transporting a fluid, comprising a jacketed casing (4) and a pump shaft (2) arranged inside the jacketed casing (4) and orientable about an axis (A), with an impeller (34) arranged on the pump shaft (2) in a rotationally fixed manner to act on the fluid, wherein the pump (1) further has a pump inlet (7) for supplying the fluid to the interior (8) and a pump outlet (6) for discharging the fluid from the interior (8), wherein one end of the jacketed casing (4) is closed with a cover (5, 51, 52) and the pump (I) comprises a fastening means (10) for fixing the cover (5, 51, 52) to the jacketed casing (4), wherein the fastening means (10) comprises a fastening element (11) and a fastening means (12) which can be arranged in an opening (13) of the element (14). (11) clamping, wherein the clamping element (11) comprises a first contact surface (111) and a second contact surface (112), wherein the clamping means (12) are arranged movably relative to the clamping element (11) along a clamping axis (X), such that the clamping element (11) is tensioned between the jacketed housing (4) and the cover (5, 51, 52) by cooperation with the clamping means (12) in an installed state of the cover (5, 51, 52), wherein, in the mounted state, a clamping force is exerted from the jacketed housing (4) via the first contact surface (111) to the second contact surface (112) on the cover (5, 51,52), so that the cover (5, 51, 52) is fixed to the jacketed housing (4) by the clamping force in the mounted state, characterized in that the clamping arrangement (10) comprises a retaining element (14) which is arranged between the clamping element (11) and the jacketed housing (4) in the assembled state, such that the clamping force is exerted from the jacketed housing (4) through the retaining element (14) onto the first contact surface (111) in the assembled state; or the clamping arrangement (10) comprises a retaining element (14) which, in the assembled state, is arranged between the clamping element (11) and the cover (5, 51, 52) such that the clamping force is exerted on the cover (5, 51, 52) by the retaining element (14) via the second contact surface (112) in the assembled state. 2. Pump according to claim 1, wherein the retaining element (14) comprises a clamping hole (16) and the clamping means (12) is arranged in the clamping hole (16) in the assembled state such that the clamping element (12) is clamped between the jacketed housing (4) and the cover (5, 51, 52) via the retaining element (14). 3. Pump according to claim 1 or 2, wherein the retaining element (14) comprises a further hole (17) and, in the assembled state, a retaining means (15) is arranged in the further hole (17) and a corresponding receptacle in the jacketed housing (4) or the cover (5, 51, 52) such that the retaining element (14) is fastened to the jacketed housing (4) or the cover (5, 51, 52). 4. Pump according to one of the preceding claims, wherein the clamping element (11) is a wedge-shaped clamping element (II) and the first contact surface (111) is a conical first contact surface (111) and the second contact surface (112) is a second annular contact surface (112). 5. Pump according to one of the preceding claims, wherein the jacketed housing (4) or the cover (5, 51, 52) comprises a protrusion (18), wherein the clamping arrangement (10) is clamped between the jacketed housing (4) and the cover (5, 51, 52) in the assembled state. 6. Pump according to one of the preceding claims, wherein the jacketed housing (4) comprises a projection (20) and the cover is arranged on the projection (20) such that the cover (5, 51, 52) is supported in axial direction by the projection (20). 7. Pump according to claim 6, wherein the cover (5, 51, 52) is arranged with a handle (22) on the projection (20) of the jacketed casing (4). 8. Pump according to one of the preceding claims, comprising a plurality of fastening means (10). 9. Pump according to claims 5 and 8, wherein the protrusion (18) is designed as a circumferential groove (18), wherein the clamping means (10) are clamped between the jacketed housing (4) and the cover (5, 51, 52) in the assembled state. 10. Pump according to claim 8 or 9, wherein the holding means (10) in the assembled state are arranged at a uniform distance from each other along a circumference of the cover (5, 51, 52). 11. Pump according to one of the preceding claims, wherein the clamping means (12) is a clamping screw (12) and the hole (13) comprises a thread corresponding to the clamping screw (12), such that the clamping screw (12) is arranged to be movable along the clamping axis (X) by rotation in the hole (13) about the clamping axis (X), such that the clamping element (11) is tensioned between the jacketed housing (4) and the cover (5, 51, 52) by cooperation with the clamping screw (12) in the mounted state of the cover (5, 51, 52). 12. Pump according to claim 3, wherein the retaining means (15) is a screw (15) or a bolt. 13. Pump according to one of the preceding claims designed as a multi-stage pump (1) comprising a plurality of stages (3) arranged in series with respect to the shaft (A), wherein the plurality of stages (3) comprises at least a first stage (31) and a last stage (33), each stage (3) having a stage housing (30) and an impeller (34) for acting on the fluid, wherein each impeller (34) is rotationally fixed to the pump shaft (2).