Wet-running centrifugal pump

Abstract

A wet-running centrifugal pump includes an electric motor (1) and a centrifugal pump (7) which is driven thereby. The electric motor (1) has a rotor (4) which is rotatably arranged within the stator (3). A canned pot (13), which carries a motor-side bearing for the rotor (4), is provided between the rotor and the stator. Moreover, a bearing plate (19) is provided, which carries a pump-side bearing for the rotor (4), wherein the bearing plate (19) is fixed on the housing side, and in the region of the pump-side bearing immerses into the canned pot. A radial seal (20) is provided between the bearing plate (19) and the canned pot (13).

Claims

1. A wet-running centrifugal pump comprising: an electric motor comprising a rotor and a stator; a centrifugal pump driven by the electric motor, wherein the rotor is arranged within the stator; a canned pot, which carries a motor-side bearing for the rotor, provided between the rotor and the stator, the canned pot being arranged in an axially floating manner, the canned pot being formed of fiber-reinforced plastic, the canned pot having a constant cross section and a bearing seat arranged on an inner side of a bottom of the canned pot; a bearing plate, which carries a pump-side bearing, for the rotor, fixed on a housing side, wherein the bearing plate, in the region of the pump-side bearing, immerses into the canned pot, the bearing plate being formed of metallic material; a centering means on the housing side to guide the closed end of the canned pot, the centering means being arranged on an outer side of the bottom of the canned pot; at least one radial seal provided between the canned pot and the bearing plate; and a ring component provided on the bearing plate side and being arranged between a part of the bearing plate which receives the pump-side bearing, and the open end of the canned pot, said ring component securing the at least one radial seal with a positive fit in the axial direction, the canned pot, at or adjacent to the open end, comprising a peripheral collar, wherein a portion of the ring component extends outside of the peripheral collar.

2. A wet-running pump according to claim 1, wherein a housing comprises a motor housing and a pump housing, the bearing plate being integrated between the motor housing and the pump housing, wherein a portion of the canned pot extends beyond the bearing seat when the bearing seat is mounted to the centering means.

3. A wet-running pump according to claim 1, wherein the at least one radial seal is formed by a radial sealing ring comprising a holding section which is integrated with a positive fit in a corresponding holding recess of the ring component.

4. A wet-running pump according to claim 1, wherein the canned pot, at or adjacent to the open end, comprises the peripheral collar which extends outwards from a tubular body of the canned pot.

5. A wet-running pump according to claim 1, wherein: a housing comprises a motor housing and a pump housing; and the pump operates with a horizontally arranged shaft and at least one opening for the discharge of fluid is provided in the motor housing.

6. A wet-running pump according to claim 5, wherein the at least one opening is arranged axially in the region, in which the peripheral collar of the can also lies.

7. A wet-running pump according to claim 1, wherein the electric motor is a permanent magnet motor controlled by a speed controller.

8. A wet-running pump according to claim 1, wherein the at least one radial seal comprises a sealing lip directed radially to a tubular part of the canned pot and comprises a radially inwardly directed, surfaced sealing seat on the bearing plate.

9. A wet-running pump according to claim 1, wherein a tubular part of the canned pot is extended beyond a canned pot base.

10. A wet-running pump according to claim 1, wherein the bearing plate has a hollow-cylindrical section which, on an inside accommodates the pump-side bearing and the radial seal engages an outer side of the hollow-cylindrical section.

11. A wet-running centrifugal pump comprising: a housing; an electric motor comprising a rotor and a stator, wherein the rotor is arranged within the stator; a centrifugal pump operatively connected to the electric motor; a canned pot comprising a constant cross section, a tubular portion and a portion defining a motor-side bearing for the rotor, the canned pot comprising a canned pot first end and a canned pot second end, said canned pot first end being located opposite said canned pot second end with respect to an axial direction of the canned pot, the canned pot not being fixedly restrained in the axial direction, wherein the canned pot is movable relative to the housing and the stator, the tubular portion comprising a bearing seat, the housing comprising a housing part, the housing part cooperating with the bearing seat to center the canned pot in the housing; a bearing plate with a portion defining a pump-side bearing for the rotor, the bearing plate being fixed to the housing, the bearing plate having a portion in a region of the pump-side bearing that extends into the canned pot, the canned pot second end being located at a spaced location from the bearing plate, wherein the canned pot first end is movable in the axial direction relative to the housing and the canned part second end is movable in the axial direction relative to the bearing plate, the housing comprising a motor housing and a pump housing, the bearing plate being fixed to the housing by integrating a portion of the bearing plate between the motor housing and the pump housing at an interface between the motor housing and the pump housing; at least one radial seal between the canned pot and the bearing plate; and a ring component arranged between a part of the bearing plate which receives the pump-side bearing, and an open end of the canned pot, said ring component securing the at least one radial seal with a positive fit in an axial direction, the canned pot, at or adjacent to the open end, comprising a peripheral collar, wherein a portion of the ring component extends outside of the peripheral collar.

12. A wet-running pump according to claim 11, wherein the canned pot comprises a fiber-reinforced plastic.

13. A wet-running pump according to claim 12, wherein the bearing plate comprises a metallic material.

14. A wet-running pump according to claim 13, wherein the housing part is located opposite said canned pot first end, the canned pot comprising a canned pot base portion, the canned pot base portion comprising the bearing seat, the tubular portion comprising a tubular end portion, said tubular end portion defining at least a portion of said canned pot first end, the tubular end portion extending to a position beyond a position of the canned pot base portion when the tubular end portion cooperates with the housing part to center the canned pot in the housing, the tubular end portion extending about a periphery of said housing part.

15. A wet-running centrifugal pump comprising: a housing comprising a housing part; an electric motor comprising a rotor and a stator, wherein the rotor is arranged within the stator; a centrifugal pump operatively connected to the electric motor; a canned pot comprising a tubular portion and a portion defining a motor-side bearing for the rotor, the tubular portion comprising a tubular first end portion and a tubular second end portion, the tubular first end portion being located opposite the housing part, the tubular first end portion being located opposite said tubular second end portion with respect to an axial direction of the canned pot; a bearing plate with a portion defining a pump-side bearing for the rotor, the tubular second end portion being movably connected to the pump-side bearing such that the tubular second end portion is movable in the axial direction relative to the bearing plate and the tubular first end portion is movable in the axial direction relative to the housing part, wherein the canned pot is movable relative to the stator and the housing, the bearing plate being fixed to the housing, the bearing plate having a portion in a region of the pump-side bearing that extends into the canned pot, the canned pot comprising a constant cross section and a canned pot bearing seat, the tubular first end portion extending to a position beyond a position of the canned pot bearing seat when the canned pot bearing seat is mounted to the housing part to center the canned pot in the housing, the canned pot comprising a fiber-reinforced plastic, the bearing plate comprising a metallic material; a radial seal between the canned pot and the bearing plate; and a ring component arranged between a portion of the bearing plate which receives the pump-side bearing, and an open end of the canned pot, the ring component securing the radial seal with a positive fit in the axial direction, the canned pot, at or adjacent to the open end, comprising a peripheral collar, wherein a portion of the ring component extends outside of the peripheral collar, wherein the tubular first end portion extends about a periphery of said housing part, the housing comprising a housing interior space, said tubular first end portion being located in said housing interior space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a view of a wet-running centrifugal pump according to the invention, in the direction of the rotation axis of the rotor, from the motor side;

(3) FIG. 2 is a sectional view along the section line II-II in FIG. 1;

(4) FIG. 3 is an enlarged longitudinal sectional representation through the motor;

(5) FIG. 4 is a detail view IV in FIG. 3, in an enlarged representation;

(6) FIG. 5 is a view of the motor housing, from the side facing the pump housing;

(7) FIG. 6 is a perspective view of the motor housing;

(8) FIG. 7 is a sectional view through a radial seal;

(9) FIG. 8 is a sectional view through a holding ring for the radial seal; and

(10) FIG. 9 is a sectional view through the holding ring and radial seal, in the joined-together condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) Referring to the drawings in particular, the represented wet-running centrifugal pump comprises an electric motor 1 with a motor housing 2 which receives a stator 3, in which a rotor 4 is rotatably mounted, said rotor comprising a shaft 5, on whose pump-side end an impeller 6 of a centrifugal pump 7 driven by this electric motor 1 is arranged.

(12) The centrifugal pump 7 comprises a pump housing 8 which in the represented embodiment is designed as an inline housing, and a suction connection 9 as well as a pressure connection 10 which are connected via a spiral housing 11, in which the impeller 6 is arranged in the usual manner.

(13) The electric motor 1 and the centrifugal pump 7 are connected to one another via housing flanges which, with the represented embodiment, are held together with a positive-fit and non-positive fit by way of a clamping ring 12.

(14) The pump assembly consisting of the electric motor 1 and centrifugal pump 7 is designed as a wet-runner, i.e. the rotor 4 of the electric motor 1 runs in a fluid which is separated by a can, here in the form of a canned pot 13, from the stator 3 having the electric connections and components. The canned pot 13 has a longitudinally extended cylindrical shape and has a base 14 close to its motor-side end. The cylindrical body of the canned pot 13 is continued beyond the base 14 and there forms part of a centering aid, whose other part is formed by an axially inwardly projecting, cone-shaped housing part 15 of the motor housing 2 which is partly covered by the tubular part, projecting beyond the base 14, of the canned pot 13 and in this manner guides and centers the motor-side end of the canned pot 13 with respect to the motor housing 2. Moreover, the canned pot 13 on its pump-side end comprises a peripheral and radially outwardly projecting collar 16 which reinforces the pot structure at the upper end and simultaneously serves for leading away liquid collecting there, in a targeted manner. The canned pot 13 consists of plastic and is fiber-reinforced in the present embodiment by way of reinforcement fibers wound in a helical manner around the cylindrical part of the pot. The can, which separates the stator 3 with the stator windings not represented individually, with respect to the rotor 4 equipped with permanent magnets, because it is of plastic, only produces minimal eddy current losses and thus further increases the already high efficiency of the permanent magnet motor.

(15) A motor-side bearing 17 for the shaft 3 comprising a central longitudinal bore is provided within the canned pot close to the base 14. A further, pump-side bearing 18 mounts the shaft 5 in the region between the motor-side part and the impeller 6. The pump-side bearing 18 is arranged in a bearing plate 19 which is incorporated between the flanges of the motor housing 2 and the pump housing 8 with a positive fit and in a sealed manner, and which together with the canned pot 13 and a radial seal 20 integrated therebetween, hermetically separates the pump housing 8 with respect to the motor housing 2, in particular the part of the motor housing 2 which receives the stator 3.

(16) The bearing plate 19 is formed from stainless steel and extends from its peripheral flange 21 radially inwards and running obliquely into the pump housing 8, in order to then extend with a hollow-cylindrical section 22 up to into the pump-side end of the canned pot 3. The pump-side bearing 18 which is a combined thrust bearing/radial bearing, is accommodated in the region of this hollow-cylindrical section 22. The thrust bearing/radial bearing, in which the shaft 5 is rotatably mounted, is fixed within the hollow-cylindrical section 22. A thrust bearing is formed by a motor-side end-face of the radial bearing in combination with a counter bearing 23 arranged on the shaft 5 in a rotationally fixed manner. This thrust bearing serves for accommodating the hydraulically caused axial forces of the pump.

(17) The outer side of the hollow-cylindrical section 22 forms a surfaced annular sealing seat for the cylindrical inner surface of the radial seal 20, whose outer surface is formed by a radially projecting sealing lip 24 which bears on the inner side of the canned pot 13. As FIGS. 3 and 4 illustrate, the canned pot 13 does not reach up to the bearing plate 19, but ends at a distance thereto, so that this is mounted in a floating manner, thus can move, expand and displace in the axial direction, wherein the sealing lip 24 ensures that a reliable sealing between the canned pot 13 and the bearing plate 19 is always given.

(18) The radial seal 20 consists of the actual peripheral seal which is essentially rectangular in cross section and has the radially outwardly pointing sealing lip 24. It comprises a likewise annularly peripheral holding section 26 which connects axially via a peripheral web 25 and engages into a peripheral groove of a holding ring 27 consisting of plastic, said holding ring, as illustrated by FIG. 4, being integrated in the region between the hollow-cylindrical section 22, the remaining bearing plate 19 and the pump-side end of the canned pot 13. As FIG. 4 illustrates, the holding section 26, when this lies in the groove of the holding ring 27, is held in the installed position with a positive fit by the surrounding components.

(19) In contrast to FIG. 2, the radial seal is represented in FIGS. 3 and 4 in the uncompressed form. Indeed, this seal 20 in the installed position is integrated between the hollow-cylindrical section 22 and the likewise hollow-cylinder-shaped inner side of the canned pot 13, as is represented in FIG. 2.

(20) The peripheral collar 16 not only serves for stabilizing the pump-side end of the canned pot 13 but moreover also as a drip edge for the discharge of liquid which has possibly collected there. Since the pump is designed and envisaged for operation with a horizontal shaft, thus as is represented in FIG. 1, the motor housing in its flange region on its lower side comprises an opening 28 for the discharge of the fluid which drops downwards at the collar 16 in the installed position. The opening 28 is led within the motor housing via labyrinth channels 29 in two openings 30 on the lower side of the motor housing. In this manner, it is ensured that splashing water directed from the outside onto the motor housing cannot penetrate to the inside.

(21) With regard to the pump assembly represented in FIGS. 1 and 2, a terminal box which is arranged on the motor housing 2 and which also comprises a frequency converter provided for the control of the speed of the motor, is not represented,

(22) Moreover, the connections for the terminal box which is not represented, are visible in FIG. 6, specifically two screw connections 31 and a central connection 32 close to the end of the motor housing 2, on which on the one hand a screw fastening is effected and on the other hand the feed-through of the connection conduits.

(23) 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.