Centrifugal pump

Abstract

The centrifugal pump (1) includes several pump stages which are arranged axially between a head part (4) and a foot part (2). An outer casing (3) peripherally surrounds the pump stages. An axial end of the outer casing (3) is fastened on the head part and the other axial end of the outer casing (3) is fastened on the foot part. A mechanical connection between the head part (4) and the foot part (2) is formed by the outer casing (3).

Claims

1. A centrifugal pump comprising: a head part; a foot part; several pump stages which are arranged axially between the head part and the foot part; an outer casing which peripherally surrounds the pump stages, wherein an axial end of the outer casing is fastened on the head part and another axial end of the outer casing is fastened on the foot part, wherein a mechanical connection between the head part and the foot part is formed by the outer casing, wherein the outer casing comprises widened axial ends; and a flange wherein one of the widened axial ends of the outer casing is fastened by the flange engaging over this end, on the head part or the foot part, the flange comprising at least two flange parts, the flange being formed from at least two identically shaped flange parts.

2. A centrifugal pump according to claim 1, wherein the axial ends of the outer casing are non-positively as well as positively fastened at least one of on the head part and on the foot part, by way of the flange.

3. A centrifugal pump according to claim 1, wherein the axial ends of the outer casing are widened stepwise.

4. A centrifugal pump according to claim 1, wherein the flange comprises a first contact surface and a second contact surface, and that the first contact surface bears on the widened axial end of the outer casing, and the second contact surface bears one of on the head part and on the foot part.

5. A centrifugal pump according to claim 1, wherein the flange is an annular loose flange.

6. A centrifugal pump according to claim 1, wherein the flange comprises recesses for leading through fastening means.

7. A centrifugal pump according to claim 1, wherein the at least two flange parts overlap at ends and in the overlapping region comprise recesses which are aligned to one another, for leading through fastening means.

8. A centrifugal pump according to claim 1, wherein at least parts of the flange are manufactured of cast metal rust-free stainless steel.

9. A centrifugal pump according to claim 1, wherein at least parts of the flange are manufactured of sheet metal which are reinforced in the region of recesses by support parts comprised of sheet metal.

10. A centrifugal pump according to claim 1, wherein the flange is screwed one of to the head part and to the foot part of the centrifugal pump in the axial direction.

11. A centrifugal pump according to claim 1, wherein the outer casing is manufactured from rust-free stainless steel sheet.

12. A centrifugal pump according to claim 1, wherein: a fluid entry of the pump is arranged one of on the foot part and on the head part and a fluid exit of the pump is arranged one of on the foot part and on the head part; and a channel for leading the delivery fluid is formed between an outer wall of the pump stages and the outer casing.

13. A centrifugal pump according to claim 1, wherein the pump is configured as an inline pump with pump stages; a fluid entry and a fluid exit are arranged on the foot part; and a pressure channel for leading the fluid from the pressure side of the last pump stage to the fluid exit is provided between an outer wall of the pump stages and the outer casing.

14. A centrifugal pump, comprising: a head part; a foot part; several pump stages which are arranged axially between the head part and the foot part; and an outer casing which peripherally surrounds the pump stages, wherein an axial end of the outer casing is fastened on the head part and another axial end of the outer casing is fastened on the foot part, wherein a mechanical connection between the head part and the foot part is formed by the outer casing, wherein the outer casing comprises widened axial ends, wherein: a radially projecting peripheral bead is provided at least one of on the head part and on the foot part; and the radially widened part at the axial end of the casing is fixed on the bead by way of a peripheral clamping ring.

15. A centrifugal pump according to claim 14, wherein the clamping ring has a u-shaped cross section with limbs that engage with a positive fit behind the radially widened end of the casing on the one hand and the bead on the other hand.

16. A centrifugal pump according to claim 14, wherein the bead includes stepwise changing shape, wherein the radially widened end of the casing is integrated into the stepping in a flush manner.

17. A centrifugal pump comprising: a head part; a foot part; several pump stages which are arranged axially between the head part and the foot part; and an outer casing which peripherally surrounds the pump stages, wherein an axial end of the outer casing is fastened on the head part and another axial end of the outer casing is fastened on the foot part, wherein a mechanical connection between the head part and the foot part is formed by the outer casing, wherein the outer casing comprises widened axial ends, wherein the axial ends of the outer casing are widened stepwise.

18. A centrifugal pump comprising: a head part; a foot part; several pump stages which are arranged axially between the head part and the foot part; and an outer casing which peripherally surrounds the pump stages, wherein an axial end of the outer casing is fastened on the head part and another axial end of the outer casing is fastened on the foot part, wherein a mechanical connection between the head part and the foot part is formed by the outer casing, wherein the outer casing comprises widened axial ends, wherein a fluid entry of the pump is arranged one of on the foot part and on the head part and a fluid exit of the pump is arranged one of on the foot part and on the head part, wherein a channel for leading the delivery fluid is formed between an outer wall of the pump stages and the outer casing.

19. A centrifugal pump comprising: a head part; a foot part; several pump stages which are arranged axially between the head part and the foot part; and an outer casing which peripherally surrounds the pump stages, wherein an axial end of the outer casing is fastened on the head part and another axial end of the outer casing is fastened on the foot part, wherein a mechanical connection between the head part and the foot part is formed by the outer casing, wherein the outer casing comprises widened axial ends, the pump being configured as an inline pump with pump stages, wherein a fluid entry and a fluid exit are arranged on the foot part, wherein a pressure channel for leading the fluid from the pressure side of the last pump stage to the fluid exit is provided between an outer wall of the pump stages and the outer casing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a greatly simplified perspective view showing a centrifugal pump with a drive motor;

(3) FIG. 2 is a greatly simplified, enlarged, partly sectioned perspective view showing a transition region between the foot part and the outer casing of the pump according to FIG. 1;

(4) FIG. 3 is a longitudinal sectional view of the part perspectively represented in FIG. 2;

(5) FIG. 4 is an exploded representation of the part represented in FIG. 2;

(6) FIG. 5 is an exploded representation corresponding to FIG. 4, showing an alternative flange fastening;

(7) FIG. 6 is a greatly enlarged sectioned representation showing the fastening of the flange represented in FIG. 5, in the region of the screw;

(8) FIG. 7 is a perspective representation showing a clamping ring fastening;

(9) FIG. 8 is a longitudinal sectional view through the components in the region of the clamping ring fastening; and

(10) FIG. 9 is an alternative flange design in an exploded representation similar to FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) With regard to the represented centrifugal pump 1, it is the case of a multi-stage inline pump. The centrifugal pump 1 is envisaged for upright operation and it comprises a foot part 2, to which an outer casing 3 connects to the top, the upper end of said outer casing being received by a head part 4 which simultaneously forms a motor base for the electrical drive motor 5 arranged thereabove. The construction of the pump represented in FIG. 1 corresponds to the basic construction of such vertical, multistage high pressure centrifugal pumps of the inline construction manner, as are manufactured and offered for example by the company Grundfos under the type description CR or CRE.

(12) The foot part 2 consisting of cast metal comprises a lower plate 6 which is formed with this as one piece, forms the actual foot of the centrifugal pump 1 and with which the centrifugal pump 1 stands on the base and can be screw-fastened to the base via bores located in the plate 6. The foot part 2 moreover has the shape of a cylindrical tube 7 with a vertical axis which on its outer periphery comprises two connection flanges 8 and 9 which are arranged lying opposite and away from one another, of which one forms the suction connection and the other the pressure connection of the pump 1. The fluid to be delivered gets via the suction connection into the foot part 2 and from there in a consecutive manner into the pump stages which connect vertically thereto and in each case consist of spiral housing and an impeller. Thereby, the arrangement is such that the exit of a lower spiral housing is conductively connected to the entry of the pump stage lying thereabove, and the exit of the last, i.e. the uppermost pump stage is connected via an annular channel to the pressure connection in the foot part 2. The annular channel on the one hand is delimited by the peripheral sides of the spiral housing which is not visible in FIG. 1 and on the other hand by the outer casing 3 which is cylindrical in this region. The impellers of all pump stages are seated on a common shaft which is driven by the drive motor 5 arranged on the head part 4 of the centrifugal pump 1.

(13) Even if the present invention is described by way of a vertical, multi-stage centrifugal pump, it is however not restricted to the vertical arrangement.

(14) The mechanical connection between the head part 4 and the foot part 2 with the represented centrifugal pump 1 is effected via the outer casing 3. The outer casing 3 arranged coaxially to the rotation axis and the shaft of the centrifugal pump has the shape of a cylindrical tube but is designed radially widened in a step-like manner at the axial ends. Such a widening consists of a flange-like, radially outwardly extending flange section 10 as well as of an annular casing section 11 which connects thereto, runs parallel to the remaining outer casing 3 and has a greater diameter than the remaining casing 3. The connection between the step-like end section of the outer casing 3 and the foot part 2 is represented by way of FIGS. 2-4 which show the axial lower end of the outer casing 3 which is connected to the foot part 2. It is to be understood that the axial upper end of the outer casing 3 as well as the connection in the head part 4 are designed in a corresponding manner, but rotated by 180 to the top in the representation.

(15) The radially running flange section 10 on the lower end of the outer casing 3 bears on a correspondingly radially i.e. in the operating position represented in FIG. 1, horizontally arranged annular end face 12 of a cylindrical, vertical projection 13 of the foot part 2. A peripheral groove 14, in which an O-ring 15 is integrated, is arranged in the outer peripheral surface of the projection 13. The outer peripheral surfaces of the projection 13 as well as of the O-ring 15 form a contact surface, with which the inner side of the casing section 11 of the outer casing 3 sealingly bears on the projection 13.

(16) A loose flange 16 which consists of two identical flange parts 17 in the form of flange halves is provided for fastening this widened end section 10, 11 of the outer casing 3 on the foot part 2. Each flange part 17 engages around the outer casing 3 by about 180. The two flange parts 17 together form a closed ring with in total six recesses in the form of vertical bores 18. These bores 18 are aligned with pocket hole bores 19 which are located therebelow, are provided with inner threads and are in a cylindrical tube section 20 which is arranged coaxially to the middle longitudinal axis of the pump 1 and in the inner region is continued to the top by the projection 13. The pocket hole bores 19 are admitted in an annular end face 21 which radially surrounds the projection 13 to the outside.

(17) The loose flange 16 formed from the two flange parts 17 in cross section to the inside has a stepped shape, and to the outside a shape conically tapering to the top, and is reinforced in the region of the bores 18 and provided with an plane end face to the top. As is to be particularly deduced from FIGS. 2 and 3, the loose flange 16 with its plane lower side 22 lies on the end face 21 of the tube section 20. The loose flange 16 moreover comprises a radial inner side 23, with which it bears on the outer side of the casing section 11. Moreover, the loose flange 16 further comprises a radially inwardly directed projection 24, with which it engages over the flange section 10 of the outer casing 3. The lower side of this radial projection 24 lies on the upper side of the flange section 10. The radial inner side of the projection 24 bears on the outer casing 3 with little play. The axially widened end of the outer casing 3 which consists of the flange section 10 and the casing section 11 is thus integrated between the projection 13 and the loose flange 16 with a positive fit and non-positive fit, so that a uniform force introduction is effected over the whole periphery between the foot part 2 and the outer casing 3. The fastening of the other axially widened end of the outer casing 3 on the head part 4 is realized in an analogous manner.

(18) The loose flange 16 formed from two identical flange halves 17, as is shown in FIG. 4, comprises two sections 25, specifically an upper section 25 and a lower section 26, which overlap in the installed condition. The upper section 25 arranged in each case on the end of each flange part 7 which is arranged on the left side seen from the middle longitudinal axis of the pump, in the installed condition has a distance to the end face 21, whereas the lower section 26 which is provided on the right-side end merges into the plane lower side 22 of the loose flange 16 in a flush manner and fills the free space forming the upper section 25 to the end face 21. Both sections 25 and 26 have a bore 18 which is axial in the installed condition, and specifically the upper section 25 a bore 18a and the lower section 26 a bore 18b, which together form a bore 18. The sections 25 and 26 in the installed condition lie above one another in pairs, wherein their bores 18a and 18b are aligned with the pocket hole bore 19 lying therebelow, in the tube section 20. The flange is fastened with screws 27, whose screw heads lie on the upper side of the flange 16 peripherally of the bores 18, whereas the shanks pass through the bores 18 and engage into the pocket hole bores 19 provided with the thread. Thus, the screw 27 also secures the flange parts 17 from releasing from one another, in the region of the overlapping sections 25 and 26. Thus, as a whole an annular and closed loose flange 16 results.

(19) With regard to the embodiment represented by way of FIGS. 5 and 6, the outer casing 3 at the end side is designed in the same manner, but there a two-part loose flange 16a is provided and this consist of two identical flange halves 17a. The flange halves in each case consist of semi-ring-shaped sheet metal section 28 which in the region of the bores 18 is designed in a reinforced manner by way of support parts 29 likewise consisting of sheet metal. The sheet metal section 28 as well as the support parts 29 are formed as punched parts of stainless steel sheet and are welded to one another for their permanent connection. Here too, the radially widened end of the outer casing 3 is fastened by way of the loose flange 16a and by way of fastening screws 27 which are led through the bores 18. On the foot part side however, a groove-like axial deepening is provided, whose outer wall 30 is recessed in the region around the bores 18, thus where the support parts 29 come to bear. The loose flange 16a here therefore lies within a groove-like deepening and is surrounded and supported by the outer groove wall. The O-ring 15 for sealing is arranged in a similar manner as with the described embodiments.

(20) One embodiment is shown by way of FIG. 9, and this corresponds essentially to the previously described ones, with which however the loose flange consists of in total six identical flange parts 17b which are fastened in each case with a screw 27 in a bore 19 in the face side of the foot part 2. These flange parts 17b are manufactured as punched parts from sheet metal and are particularly inexpensive in manufacture.

(21) With the embodiment represented by way of FIGS. 7 and 8, the foot part 2 comprises a peripheral bead 31 which, as is to be deduced from FIG. 8, is stepped and is designed tapering to the top, so that the radially widened part at the end of the outer casing 3 can be received in an aligned or flush manner. The radially widened part corresponds essentially to the previously described one, i.e. a casing section 11 is provided which runs parallel to the outer casing 3 but has a greater diameter, as well as a flange section 10 which however with this embodiment does not run perpendicularly to the outer casing, but obliquely thereto. The sealing here is effected in the bead region, and specifically via an O-ring 15a which bears on the inner side of the casing section 11.

(22) The fastening of the components is effected via a clamping ring 32 which has a roughly U-shaped cross-sectional shape and engages around the peripheral bed 31 with the widened end of the outer casing 3, with a positive fit. The clamping ring 32 is formed from sheet metal and comprises two reinforcement wires 33 which are integrated into the clamping ring 32 and are fastened on bearing bodies 34 which can be adjusted in their distance to one another via two clamping screws 35.

(23) For assembling the clamping ring 32, the clamping screws 35 are set such that the bearing bodies 34 have a maximal distance, i.e. the clamping ring 32 is tensioned open and can thus be pushed over the bead 31 and the radially widened end of the outer casing 3. Subsequently, the clamping screws 35 are tightened until the clamping ring 32 engages around the end of the outer casing 3 and the foot part 2 on the other side of the bead in a firm manner and thus connects the components inserted therein to one another.

(24) The connections between the outer casing 3 and the foot part 2 described above are here only described by way of example and by way of the foot part 2 and are effected in the same manner at the head part 4. Connections of a different construction type can also be provided on the foot part 2 and the head part 4.

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