MULTI-STAGE CENTRIFUGAL PUMP HAVING TIE RODS FORMED FROM SHEET METAL

Abstract

A multistage centrifugal pump with a foot part (2) and with a head part (9), between which pump stages are integrated. The head part (9) and the foot part (2) are connected via tie-rods (11) which with one end are fastened on the head part (9) and with the other end are fastened on the foot part (2). The tie-rods (11) at one end comprise a thread (14), with which they are tightened on the head part (9). The tie-rods (11) are formed from sheet metal and at the other end comprise a recess (16), with which recess they are positively fixed on the foot part (2), at least one the tensile direction 22

Claims

1. A multi-stage centrifugal pump comprising: a foot part; a head part pump stages integrated between the foot part and the head part, said pump being designed as an inline pump; a suction connection and a delivery connection in the foot part wherein the pump stages are surrounded by an annular channel, by way of which the last pump stage is connected to the delivery connection, the annular channel having an outer channel wall; tie-rods arranged on the outer channel wall, said tie-rods connecting the head part and the foot part to one another, each of the tie-rods being fixed with one end to the head part and with another end to the foot part, wherein the tie-rods each comprise a thread end, with which thread end the tie-rods are tightened on the head part or on the foot part and the tie-rods comprise at least one sheet metal section.

2. A centrifugal pump according to claim 1, wherein the tie-rods at the other end each comprise at least one projection positively fixing the other end to the foot part or to the head part, at least in a tensile direction.

3. A centrifugal pump according to claim 2, wherein the projection is formed by a sheet metal part which is connected to a part of the tie-rod formed from sheet metal, by way of welding.

4. A centrifugal pump according to claim 3, wherein the sheet metal part which forms the projection surrounds the part of the tie-rod which is formed from sheet metal, in a U-shaped configuration and comprises at least one opening for receiving a weld seam.

5. A centrifugal pump according to claim 2, wherein the projection is arranged in a peripheral direction of the annular channel wall and further comprising another projection wherein two projections are arranged in opposite peripheral directions.

6. A centrifugal pump according to claim 2, wherein the at least one projection is arranged in the a peripheral direction of the annular channel wall and is formed by an edge recess in the sheet metal, said at least one projection projecting in a peripheral direction with respect to the edge recess.

7. A centrifugal pump according to claim 6, wherein the tie-rods each comprise an edge recess on both longitudinal sides, said edge recesses being arranged at the same height.

8. A centrifugal pump according to claim 1, wherein each thread comprises a threaded bolt which by way of welding is connected to the sheet metal section of the tie-rod.

9. A centrifugal pump according to claim 1, wherein hole recesses are provided in the head part, through which hole recesses the thread ends of the tie-rods are led and are fixed and tightened in each case by way of a nut, wherein the head part comprises a motor support.

10. A centrifugal pump according to claim 1, wherein a cylindrical wall section in the region of the annular channel, between the foot part and the head part comprises a surface with a curvature and the at least one sheet metal section of the tie-rods comprises a curvature which is adapted to the curvature of the cylindrical wall section.

11. A centrifugal pump according to claim 2, wherein rod recesses which comprise an introduction part and a holding part are provided in the foot part, wherein the introduction part is configured such that an end of a tie-rod can be led through, and the holding part is configured such that the end of the tie-rod can be brought with the at least one projection into the holding part by way of radially displacing or by way of pivoting or by way of both radially displacing and pivoting, such that the tie-rod is positively held at least in a direction of a pump longitudinal axis.

12. A centrifugal pump according to claim 11, wherein the rod recesses are arranged in the foot part in a circular configuration around the pump longitudinal middle axis and introduction parts are covered by a component of the pump for the positive fixation of the tie-rods.

13. A centrifugal pump according to claim 11, wherein the holding parts connect radially outwards onto the introduction parts of the rod recesses, and a cylindrical section of the component positively fixes the ends of the tie-rods in the rod recesses.

14. A centrifugal pump according to claim 11, wherein the rod recesses are arranged in an axial wall of the foot part.

15. A centrifugal pump according to claim 11, wherein the introduction parts of the rod recesses are arranged in a radial wall and the holding parts of the recesses are arranged in an axial or radial wall of the foot part.

16. A centrifugal pump according to claim 1, wherein both the head part and the foot part or the head part or the foot part is configured as a metal cast part, wherein the foot part is configured for placing the pump on a support surface and the head part is configured for receiving an electric motor which drives the pump.

17. A centrifugal pump according to claim 1, wherein the at least one sheet metal section extends at least from the foot part up to the head part.

18. A centrifugal pump according to claim 1, wherein the foot part comprises a pot-shape structure and the rod recesses are arranged in the region, in which the pot base merges into the pot wall.

19. A centrifugal pump according to claim 1, wherein the at least one sheet metal section is radially inwardly supported in a region of the head part by way of supports.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the drawings:

[0033] FIG. 1 is a greatly simplified perspective representation of a first embodiment of a centrifugal pump according to the invention;

[0034] FIG. 2 is an exploded representation of the centrifugal pump according to FIG. 1;

[0035] FIG. 3 is a bottom perspective view, from below with a fixed tie-rod, of the foot part of the pump according to FIG. 1;

[0036] FIG. 4 is a perspective view, obliquely from above, of the arrangement according to FIG. 3;

[0037] FIG. 5 is a greatly simplified perspective representation of a different embodiment example of the centrifugal pump;

[0038] FIG. 6 is a perspective view of the pump according to FIG. 5, with a foot part in part-section and with a tie-rod in the introduction position;

[0039] FIG. 7 is an exploded representation of the pump according to FIG. 5;

[0040] FIG. 8 is a perspective view, obliquely from the front and above, of a foot part of the pump according to FIG. 5;

[0041] FIG. 9 is a perspective view of the foot part according to FIG. 8, in a view which is rotated by 90 with respect to FIG. 8;

[0042] FIG. 10 is a perspective view from below of the foot part according to FIG. 8;

[0043] FIG. 11 is a lateral partially longitudinal sectional view illustrating the design construction of a comparably constructed centrifugal pump with a connected electric motor;

[0044] FIG. 12 is a perspective representation of an alternative embodiment of a foot part with a tie-rod end with an alternative configuration;

[0045] FIG. 13 is a perspective view from below of the arrangement according to FIG. 12;

[0046] FIG. 14 is a lateral view, radially from the outside, of a tie-rod as is represented by way of FIGS. 12 and 13;

[0047] FIG. 15 is a lateral view, from the peripheral direction, of the tie-rod;

[0048] FIG. 16 is a lateral view, radially from the inside, of the tie-rod;

[0049] FIG. 17 is a view of the tie-rod from above;

[0050] FIG. 18 is a view of the tie-rod from below; and

[0051] FIG. 19 is a perspective representation of an alternative design of a pump assembly with a drive motor, concerning which the tie-rods are led through to the motor stool.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] Referring to the drawings, with regard to the centrifugal pump 1 which is represented by way of FIG. 1, it is the case of a multi-stage centrifugal pump of the inline construction type (see also FIG. 11). It comprises a foot part 2 which with its lower side is envisaged for placement on the ground or a suitable foundation. The foot part 2 essentially has the shape of a rectangular plate which at its corners comprises four fastening recesses 3, with which the foot part 2 can be screw-fastened on the foundation, in which suitable cap screws are led through these recesses 3 and are anchored in the foundation. The foot part 2 comprises a circular receiver 4, which is provided for receiving a component which comprises a suction connection 5 as well as a delivery connection 6 and which receives pumps stages connecting thereto at the top, said pump stages being closed to the top by a cover part 7. A cylindrical tube section 8 is arranged between the cover part 7 and the component receiving the suction and delivery connection 5, 6, wherein this tube section surrounds the pump stages at a distance and forms an annular channel, via which the fluid exiting at the end of the last pump stage is led to the delivery connection 6. The pump is closed to the top by a head part 9 which at the same times forms a motor stool for an electrical motor which can be flanged on there.

[0053] The component comprising the suction and delivery connection 5, 6, the pump stages which connect thereto, the tube section 8 surrounding these and the cover part 7 are positively and non-positively clamped between the foot part 2 and the head part 9, and specifically by way of four tie-rods 11 which are arranged symmetrically about the longitudinal and rotation axis 10 of the pump. These tie-rods 11 are manufactured from sheet metal and have a longitudinally extended, narrow shape and are bent about their longitudinal axis in a manner corresponding to the curvature of the tube section 8, so that these continue outwards as is evident from FIG. 1. The tie-rods 11 comprise a lower end 12 which is likewise formed from sheet metal as well as an upper end 13 which is formed by a bolt 14 which is provided with an outer thread and is fixedly connected to the upper end of the part of the tie-rod 11 which is manufactured from sheet metal, by way of welding. The sheet metal section 15 is provided with two recesses 16 on its longitudinal side, towards the lower end 12, and these recesses are arranged at the same height and their lower side is recessed inwards by 90 and their upper side tapers obliquely to the outer edge of the sheet-metal section 15. Four rod recesses 18 whose contour can be recognized best of all from FIG. 4 are provided in the foot part 2, and specifically at the edge of the receiver 4, in the axial wall 17, for anchoring these lower ends 12 of the tie-rods 11.

[0054] Each rod recess comprises an introduction part 19 as well as a holding part 20 which are matched to the lower end 12 of a tie-rod. The introduction part 19 is thus dimensioned such that it corresponds to the cross-sectional area of the sheet-metal section 15 which is to say that the tie-rod 11 with its lower end 12 and the projections 31 can be inserted from above into the introduction part 19 and led through this. This lower end 12 is inserted into the introduction part 19 so far, until the recesses 16 are arranged at the height of the rod recess 18, and thereafter the tie-rod 11 in the rod recess 18 is displaced radially outwards, so that the comparatively narrow web part 21 formed between the recesses 16 in the sheet-metal section 15 gets into the holding part 20 of the rod recess 18, by which means the tie-rod 11 is fixed in the foot part 2 with a positive fit in the tensile 22 by way of the projections 31. Thereby, the holding part 20 of the rod recess 18 which is arranged in the axial wall 17 of the recess 4 is continued in the radial wall 23 of the receiver 4 in a manner corresponding to the recesses 16 tapering obliquely upwards, so that the tie-rod in this position is arranged outside the actual receiver 4, specifically radially offset thereto.

[0055] The receiver 4 which with regard to its dimensioning is provided for receiving the component receiving the suction and delivery connection 5, 6, can receive this component after integrating the tie-rods 11, as was hitherto the case, but with the effect that the introduction parts 9 of the rod recesses 18 are closed due to the integration of the component into the receiver 4, and thus the lower ends 12 of the tie-rods 11 with their projections 31 are positively fixed within the foot part 2.

[0056] The remaining pump parts, in particular the pump stages, the tube section 8 and the cover part 7 can be integrated as soon as the tie-rods 11 are fixed positively within the foot part 2, whereupon the head part 9 is applied from the top. Thereby, the upper ends 13, thus the bolts 14 which are provided with a thread, go through hole recesses 24 into the head part 9, said hole recesses 24 being arranged in a manner aligned to the rod recesses 8 arranged in the foot part 2, so that after placing on the head part, the bolts 14 which project through the hole recesses 24, amid the intermediate arrangement of washers, are provided with nuts 25 and are tightened. The complete centrifugal pump 1 obtains a closed and stable structure by way of this, wherein, the tie-rods 11 bear on the pump body which is otherwise cylindrical there, as is evident in particular from FIG. 1, so that as a whole, a slim outer contour practically without projections in the radial direction arises.

[0057] With the embodiment variant which is represented by way of FIG. 5-10, the suction connection 5 and the delivery connection 6 are integrated into the foot part 2a. There, the tube section 8 which delimits the annular channel to the outside extends between the foot part 2a and the head part 9a. The construction in detail in particular is to be deduced from FIG. 7. With this design, the head and foot parts 9a, 2a which consist of cast metal are not lined with stainless steel sheet as in the previous embodiment, but form parts of the flow channels. The basic construction is similar, but the receiver 4a is configured in a closed manner, which is to say without recess on the inner side. This is necessary in order to ensure the sealedness with respect to the tube section 8. The rod recesses 18a which surround the receiver 4a are provided here and these are arranged at the outer side of the receiver 4a and comprise a radial introduction part 19a and an axial holding part 20a. The radial introduction part 19a of a rod recess 18a lies in a radial wall 23a which surrounds the receiver 4a at a distance and receives the delivery connection and the suction connection 5, 6. This radial wall 23a at its upper end merges in a shouldered manner into an axial wall 17a, but is not a part of the receiver 4a, but forms an outer shoulder.

[0058] The tie-rod 11 itself is configured just as in the previously described embodiment. Here however, as is to be seen in particular in FIG. 6, they are inserted obliquely from the outside and from the top through the introduction part 19a, thus the rod recess part in the radial wall 23a, until the recesses 16 or the web 21 of the tie-rods 11 are arranged at the height of the holding parts 20a of the rod recesses 18a. The tie-rod 11 is then pivoted obliquely upwards, until this is present at a distance parallel to the tube section 8, and the bolt 14 provided with a thread engages into the laterally open hole recess 24a, opposite whose upper end, as with the preceding embodiment, it is screwed to a nut 25 amid the integration of a washer, and thus tightened. On pivoting in the tie-rod 11, roughly about an axis running tangentially to the upper edge of the foot part 2a, the narrow sheet metal section 21 gets between the recesses 16 into the region of the holding part 20a of the rod recess 18a in the axial wall 17a, by which means the parts of the sheet metal section 15 which project with respect to this assume a positive connection in the pulling or tensile direction 22 and in the opposite direction. The tie-rods 11 are held in this position by way of the threaded bolt 14 which is fixed by way of the nut 25 and with which the upper end 14 of the tie-rod 11 is fastened on the head part 9a.

[0059] The holding part 20a of a rod recess 18a, with the described embodiment is provided in the axial wall 17a, but this part of the rod recess 18a can also be provided in the radial wall 23a, if this is dimensioned accordingly and comprises a recess or opening which is matched to the lower end 12 of the tie-rod 11, which is to say corresponds to this with regard to the shape.

[0060] The significant advantage with the previously described arrangement lies in the fact that the pump can be constructed quasi in a complete manner starting from the foot part 2a up to the head part 9a, whereupon the tie-rods 11 are subsequently introduced into the rod recesses 18a and are secured there with a positive fit by way of pivoting. The respective tension between the foot part 2a and the head part 9a is then incorporated by way of tightening the nut 25 with the envisaged torque. This construction type is therefore particularly suitable for an at least part-automated assembly.

[0061] The basic construction of such a centrifugal pump with a drive is represented by way of FIG. 11, and this, as the horizontal interrupt lines illustrate, is to represent multistage centrifugal pumps with a quasi infinite pump stage number. A drive motor 26 in the form of an electric motor is attached on the head part 9a which at the upper end is configured as a motor stool, for the drive of the centrifugal pump, wherein the shaft 27 of the electric motor is connected in a rotationally fixed manner to a shaft 28 of the centrifugal pump 1 by way of a coupling. Impellers 29 are arranged on the drive shaft 28 of the centrifugal pump in a rotationally fixed manner according to the stage number and together with diffusers 30 fixed with regard to the casing form the pump stages.

[0062] The delivery fluid is led via the suction connection 5 (not visible in FIG. 11) to the suction port of the lowermost pump stage, and from there goes from pump stage to pump stage amid a pressure increase to the top where it exists within the head part 9a and is led via an annular channel 31 back down again to the foot part and there to the delivery connection 6.

[0063] An alternative design of the tie-rods 11b is represented by way of FIGS. 12 to 18, said design differing from that of the aforementioned tie-rods 11 in that the sheet metal section 15b has a constant cross section over the entire length, thus is not weakened by lateral recesses. A threaded bolt 14 is welded to the upper end in the same manner as the previously described embodiment. However, the projection 31b at the lower end is formed by a sheet metal section 33 which has an essentially U-shaped cross section, is adapted in the web region to the curvature of the sheet metal section 15b and whose U-limb 34 laterally surround the end of the sheet metal section 15b, so that a partly peripheral projection 31b results, said projection being formed on the radial outer side of the sheet-metal section 15b in the web region of the U-shaped sheet-metal section 33 as well as in the peripheral directions by way of the limbs 34. The sheet metal section 33 comprises two elongate-hole-shaped openings 35 which extend in the longitudinal direction of the tie-rod 11b and are arranged parallel to one another (see FIG. 14). These openings 35 serve for incorporating a weld seam between the sheet-metal section 33 and the sheet metal section 15b and ensure a uniform introduction of force from the sheet metal section 33 onto the sheet metal section 15b. As is evident from FIG. 16, the sheet metal section 15b is not led completely up to the lower end of the sheet metal section 33, by which means the effective length of the tie-rod 11b is not set until welding on the sheet metal section 33.

[0064] The foot part 2b is provided for the positive anchoring of the lower ends of the tie-rods 11b, said foot part with regard to its basic construction corresponding essentially to the foot part 2 of the first embodiment, but with regard to the rod recesses 18b being adapted to the lower ends of the tie-rods 11b, particular with regard the projections 31b. The rod recesses 18b are configured such that the axial wall 17 comprises rod recesses 18b which are configured such that the lower end of the sheet metal section 15b can be led with the sheet metal section 33 which is welded thereto, through an introduction part 19b and then displaced radially outwards, in a manner such that the sheet metal section 15b passes through the holding part 20b of the rod recess 18b, but the sheet metal section 33 which forms the projection 31b is positively held, and specifically by the lower face side of the radial wall 23b, on which the sheet metal section 15b bears. Herein, with this embodiment too, it is the case that the component which is then integrated with the tube section 8 and which comprises the delivery connection 6 and the suction connection 5 positively holds the ends of the tie-rods 11b in this position, in which the projections 31b positively fix the tie-rods to the foot part 2b in the tensile direction.

[0065] With regard to the tie-rods 11b, this embodiment compared to the aforementioned one has the advantage that with regard to their cross section, i.e. with regard to their width and thickness, they can be dimensioned exclusively in the light of the expected tensile forces, whereas the projections 31b are formed by the separate sheet metal sections 33 which are each connected to the sheet metal section 15b by way of welding.

[0066] A design variant, concerning which the head part 9b which simultaneously forms the motor stool is configured such that an outer flange 36 is formed at the motor stool side is represented by way of FIG. 19, said outer flange being dimensioned in a manner such that the tie-rods 11b can be led through upwards to into this flange, where they are fixed with their threaded bolts 14 by way of nuts in a manner such that the pump stages with the tube section 8 and with the component which receives the suction and delivery connection 5, 6 are clamped between the head part 9b and the foot part 2b. In order to provide the sheet metal sections 15b of the tie-rods 11b with a sufficient stability in the region of the head part 9b, comparable to the bearing contact on the tube section 8, supports 37 are provided there, and these supports extend between the part of the head part 9b which connects directly onto the tube section 8 and the flange 36, and on which supports the tie-rods 11b bear on this region and are supported radially to the inside.

[0067] It is to be understood that this embodiment variant according to FIG. 19 is not limited to the represented tie-rods 11b in combination with the foot part 2b, but that here the previously described tie-rods and foot part designs can also be applied as an alternative.

[0068] 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.