Vortex pump

Abstract

A centrifugal pump for delivering a medium comprising solid admixtures includes a blade-free space arranged in front of an impeller. The centrifugal pump has a suction-side arrangement that permits variable sizing of the blade-free space. The suction-side arrangement permits the efficiency of the centrifugal pump to be increased while avoiding blockages.

Claims

1. A centrifugal pump for conveying a medium comprising solid additives, comprising: a pump casing having a casing space; an impeller arranged in the casing space with a blade-free space upstream of the impeller between the impeller and an inlet of the pump casing; and a guide body having an inner wall defining the inlet, an outer wall attached to the pump casing, and a ring-shaped space radially between the inner wall and the outer wall a hollow body arranged in the ring-shaped space, the hollow body being configured to be displaced axially along the inner wall and the outer wall toward or away from the impeller to change a size of the blade-free space in response to receipt or withdrawal of a filling fluid in the hollow body.

2. The centrifugal pump as claimed in claim 1, wherein the hollow body is ring-shaped.

3. The centrifugal pump as claimed in claim 1, wherein the hollow body has an elastic wall configured to change the size of the blade-free space by expansion or contraction of the elastic wall.

4. The centrifugal pump as claimed in claim 3, wherein the hollow body has a port configured to receive and discharge the filling fluid.

5. The centrifugal pump as claimed in claim 1, wherein the inner wall and the outer wall are configured to guide axial movement of the hollow body during a change of the size of the blade-free space.

6. The centrifugal pump as claimed in claim 1, wherein the hollow body is arranged on a suction-side of the pump casing.

7. The centrifugal pump as claimed in claim 1, wherein the displaceable hollow body is configured to change the size of the blade-free space in response to detection of one or both of a pressure drop and a power consumption of the pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a section through a vortex pump in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(2) FIG. 1 shows a vortex pump for conveying a medium comprising solid additives. The pump comprises an impeller 1, which in this embodiment is designed as a vortex impeller. The impeller 1 is at least partially enclosed by a casing 2. The impeller 1 is positioned on a shalt 3, which can be driven in rotation about an axis of rotation X by a drive 4. The fastening of the impeller 1 is realized by a hub body 5, into which a screw 6 engages.

(3) Multiple blades 8 are arranged on a rear shroud 7 of the impeller 1. Between the impeller 1 and an inlet-side casing wall 9, there is formed a blade-free space 10, which is flowed through by the medium. The medium comprising solid additives flows to the impeller 1 through an axially directed inlet 11. The medium is conveyed by the impeller 1 and exits the centrifugal pump through an outlet 12. The casing 2 illustrated in FIG. 1 is a spiral casing.

(4) The centrifugal pump has a variable suction-side arrangement 13. The arrangement 13 is, in this embodiment, integrated into an opening 14 of the inlet-side casing wall 9. The variable suction-side arrangement 13 is, in this embodiment, of ring-shaped form.

(5) Said arrangement comprises a guide body 15 which extends into the opening 14 from the outside and which has an inner ring-shaped guide wall 16 and an outer ring-shaped guide wall 17. The inner guide wall 16 furthermore forms the axially directed inlet for the medium. In the guide wall 17, there is formed at least one guide groove 18 which extends, parallel to the axis of rotation X, from a region averted from the space 10 approximately as far as the center of the outer guide wall 17.

(6) The variable arrangement 13 furthermore comprises an axially movable element which, in the embodiment shown, constitutes a movement body 19 which can be guided axially by the guide walls 16 and 17 and which is of ring-shaped design and which has an inner ring wall 20, which interacts with the guide wall 16, and an outer ring wall 21, which interacts with the guide wall 17. The ring wall 20 and ring wall 21 are connected to one another, close to the space 10, by a ring-shaped disk 22.

(7) Since the inner ring wall 20 has a smaller height in an axial direction than the outer ring wall 2, the ring-shaped disk 22 has a conical design. The ring-shaped wall 21 has axially outwardly directed projection 23 which projects into the guide groove 18. By virtue of the fact that the guide groove 18 extends substantially as far as the center of the guide wall 17, a shoulder 24 is formed there, against which the projection 23 of the movement body 19 bears during normal operation. Thus, the axial movement of the movement body 19 into the space 10 is limited. In the embodiment illustrated, the guide body 15 is fixed by a closure element 25 in the opening 14 of the casing wall 9 of the casing body 2. The closure element 25 is fixed to the inlet-side casing wall 9 by fastening means which are not illustrated. In an alternative embodiment, the guide body 15 and movement body 19 may be formed as a single piece.

(8) The guide walls 16 and 17 form, together with the ring-shaped walls 20 and 21, a ring-shaped space 26 in which an elastic wall 28, which forms a hollow body 27, is arranged. In this embodiment, the elastic wall 28 is designed as an expandable diaphragm. Through at least one port device 29, a filling fluid, for example in the form of hydraulic oil or compressed air, can be fed to the hollow body 27, which is displaced in an axial direction in the direction of the impeller 1, and in so doing expands the diaphragm 28, owing to the pressure of the filling fluid. In this way, the movement body 19 is moved in the direction of the blade-free space 10, whereby the latter is reduced in size. This arrangement of the movement body 19 corresponds to normal operation. A smaller ball passage therefore also results, which is illustrated in FIG. 1 as a schematic line with a relatively small ball diameter. In this position of the arrangement 13, the centrifugal pump exhibits high efficiency.

(9) If a blockage is detected by a detector which is not illustrated in FIG. 1, then the arrangement 13 reacts and increases the size of the blade-free space 10 through which flow passes. For this purpose, the filling fluid is released out of the hollow body 27 and the diaphragm 28 contracts. The movement body 19 is moved in the axial direction out of the blade-free space 10. As a result, a larger ball passage is ensured, which is schematically illustrated in FIG. 1 as a circle with the relatively large diameter.

(10) The arrangement 13 according to the invention permits a continuously variable variation of the front impeller side space 10, without the impeller 1 having to be displaced in terms of its position.

(11) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.