CENTRIFUGAL PUMP WITH SELF-CLEANING WEAR PLATE

Abstract

A centrifugal pump having an impeller assembly within a pump housing and a wear plate positioned in confronting relationship with the impeller assembly. The wear plate includes an annular wear plate portion defining an impeller side that confronts the impeller and further defines an annular portion defining an eye formed generally centrally and has a center point that is substantially aligned with a rotational axis of the impeller. The eye includes a plurality of peripheral notches separated by tooth-like spacer gaps. At least one protrusion extends from the eye towards the impeller at a predetermined angle. Inner and outer radial grooves are formed in the wear plate surface that confronts the impeller.

Description

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/895,131, filed on Oct. 24, 2013, the disclosure of which is entirely incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to pumps and, in particular, to a centrifugal type pump that has enhanced solid handling properties.

BACKGROUND ART

Centrifugal pumps are typically used to pump sewage and wastewater. Sewage, in particular, often includes solids that must pass through the impeller chamber of the centrifugal pump. In the past, impeller/impeller chambers were designed to allow solids up to a predetermined size to pass through the pump without clogging. More recently, it has been found that sewage effluent in addition to solids, also carries stringy and fibrous materials which can clog or compromise the operation of conventional centrifugal pumps.

SUMMARY OF THE INVENTION

The present invention provides a new and improved centrifugal pump, including a self-cleaning wear plate. The disclosed wear plate significantly improves a pump's ability to resist clogging due to stringy or fibrous materials without sacrificing the ability of the pump to handle spherical waste material.

According to one preferred embodiment, a centrifugal pump is disclosed which includes a pump housing and an impeller assembly mounted to the pump housing. A wear plate constructed in accordance with the invention is mounted within the housing in a confronting relationship with an impeller that forms part of the impeller assembly. According to one embodiment, the wear plate includes an annular wear plate portion that defines an impeller side that confronts the impeller when the wear plate is mounted within the pump housing. The annular portion also defines an eye formed generally centrally in the annular portion and includes a center point that is substantially aligned with a rotational axis of the impeller. According to this embodiment, the wear plate includes at least one protrusion that extends towards the impeller. The protrusion includes a prong that extends at an angle from a mounting segment formed on the wear plate. In a more preferred embodiment, the prong extends at an angle of substantially 45° with respect to a plane defined by the wear plate portion. In this embodiment, the prong and mounting segment are integrally formed with the wear plate portion and in another disclosed embodiment, the prong is welded to the mounting segment.

According to the preferred embodiment, the eye includes at least one peripheral notch. In the illustrated embodiment, the eye includes a plurality of peripheral notches separated by tooth-like gaps or spacing members and one protrusion extends from the eye toward the impeller. In the illustrated embodiment, the notches are substantially wider in dimension than the tooth-like gaps or spacers

According to a feature of the invention, the wear plate portion includes at least one substantial radial groove and, in a more preferred embodiment, includes a second radial groove with the one radial groove extending inwardly from an outer diameter of the wear plate portion and the second groove extending outwardly from the eye. In one illustrated embodiment the grooves extend below a wear plate surface but do not extend through the wear plate. In another illustrated embodiment, the grooves extend through or cut through the wear plate portion.

In the illustrated embodiment, the wear plate is attached to a wear plate cover, preferably by stand-offs forming part of the wear plate. In a more preferred embodiment, an aperture is formed in the protrusion to facilitate bending of the prong when the protrusion is integrally formed with the annular wear plate portion. In the illustrated embodiment, one radial groove has an inner end that is in a radial, overlapping relationship with respect to the outer end of the other radial groove. The disclosed construction of the wear plate includes a single prong and a single and a single outer radial groove. It should be noted that the present invention contemplates multiple protrusions that would extend towards the impeller for some applications. In addition, the depths of the radial grooves can be uniform or can vary and more than two radial grooves (both inner and outer) can be used to improve performance for some applications. In addition, in the illustrated construction, the notches formed on the periphery of the eye or center aperture of the wear plate are substantially wider than the tooth-like gaps or fingers. The present invention contemplates notches that can be smaller than those shown, as well as a pattern of notches in which the width of the notches varies along the periphery of the wear plate eye.

The disclosed wear plate improves the performance of a centrifugal pump because it is better able to handle fibrous and stringy materials without comprising its ability to handle larger spherical waste material which centrifugal pumps of this type were originally intended to handle.

Additional features of the invention will become apparent and a fuller understanding obtained by reading the following description made in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded view of a centrifugal pump, including assemblies constructed in accordance with a preferred embodiment of the invention;

FIG. 2 is isometric view of a wear plate constructed in accordance with a preferred embodiment of the invention;

FIG. 3 is another isometric view of the wear plate shown in FIG. 2 that illustrates another side of the wear plate shown in FIG. 2;

FIG. 4 is an isometric view of a wear plate constructed in accordance with another preferred embodiment of the invention;

FIG. 5 is an enlarged fragmentary view of a portion of the wear plate indicated by the phantom circle shown in FIG. 4 and constructed in accordance with one embodiment of the invention;

FIG. 6 is another enlarged fragmentary view of a portion of the wear plate indicated by the phantom circle in FIG. 4, but constructed in accordance with another embodiment of the invention;

FIG. 7 is isometric view of a back cover or wear plate access cover constructed in accordance with a preferred embodiment of the invention;

FIG. 8 is another isometric view of the wear plate access cover shown in FIG. 7, but rotated 180°;

FIG. 9 is a plan view of a wear plate blank prior to a bending operation; and

FIG. 10 is an isometric view of a wear plate constructed in accordance with another preferred embodiment of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 illustrates the overall construction of a centrifugal pump 10 constructed in accordance with a preferred embodiment of the invention. The pump includes a pump housing 10a which, as is known, defines an inlet and an outlet for receiving and discharging effluent and an internal chamber for receiving an impeller assembly 10b and a wear plate assembly 10c. The illustrated wear plate assembly 10c is constructed in accordance with a preferred embodiment of the invention. The illustrated centrifugal pump is of the self-priming variety. Additional details regarding the pump body and impeller assembly can be found in U.S. Pat. Nos. 3,898,014 and 8,414,257, which are hereby incorporated by reference.

FIGS. 2 and 3 illustrate a wear plate 20 constructed in accordance with one preferred embodiment of the invention. As seen in FIG. 2, the wear plate 20 includes two studs 22 by which the wear plate is attached to a back or wear plate access cover 24 (see also FIGS. 7 and 8). It should be noted here that the cover 24 best illustrated in FIGS. 7 and 8 includes adjustment hardware for adjusting the distance between the wear plate 20 and an associated impeller 32 (see FIG. 1). The details of this wear plate adjustment feature can be found in U.S. Pat. No. 6,887,034 which is hereby incorporated by reference.

As seen in FIGS. 2 and 3, the wear plate 20 is generally circular in construction and includes an annular portion that includes an eye 34 which forms at least part of the inlet to the impeller chamber which is defined within the pump body 10a when the impeller assembly 10b and the wear plate assembly 10c are mounted to the pump body 10. The eye 34 is a generally circular opening located at or near the center of the wear plate 20. A center 38 of the eye 34 is preferably located in line with the rotational axis of the impeller 32.

According to the invention, the outer periphery of the eye 34 is characterized by at least one notch, but preferably a plurality of notches 46 that are separated by gaps or spacer teeth 48. In the illustrated embodiment, the spacer teeth extend radially inwardly from the periphery of the eye or aperture 34. The notches 46 can be of a different number, width or depth from that shown. It is also believed that a wider notch 46 provides better performance than a narrower notch.

For purposes of reference, a side of the wear plate 20, which includes the mounting studs and faces the wear plate cover 24, shall be indicated by the reference character 20a. A side of the wear plate includes a surface that confronts the impeller 32 as shown in FIG. 3 shall be indicated by the reference character 20b. The illustrated wear plate confronting surface 20b is generally planar. The present invention contemplates a tapered confronting surface which would be used with a tapered impeller.

In the illustrated embodiment shown in FIG. 3, the wear plate side 20b of the wear plate 20 includes inner and outer grooves 50, 52 which extend generally radially. As seen in FIG. 3, the inner groove 50 opens into the impeller eye, whereas the outer groove opens at the periphery or outer diameter of the wear plate. In the embodiment illustrated in FIG. 3, the grooves are cut partially into the wear plate but do not extend from the side 20a to the side 20b of the wear plate. The inner and outer grooves 50, 52 can be of a varying number, position, angle and depth.

According to the invention, the wear plate also includes at least one protrusion 60 which extends from the plane of the wear plate 20, towards the impeller 32 and through the eye 34. Referring also to FIGS. 1 and 7, the extension of the protrusion 60 towards the impeller can be seen. Referring also to FIGS. 4-6, the protrusion includes a mounting segment 62 which extends radially from the wear plate 20 and a tooth or prong 64 which extends towards the impeller 32. The tooth or prong 64, which in the illustrated embodiment is generally triangular in shape and includes an apex or point 64a, is joined to the mount 62 by an interconnecting portion 66. FIG. 5 is an enlargement of a portion of FIG. 4 which shows a configuration of the protrusion 60 when it is integrally formed with the wear plate 20. FIG. 6 shows an alternate construction in which a tooth segment 64′ is welded to a lug or mount segment 62′.

FIG. 4 also illustrates an alternate embodiment of the wear plate 20′ in which inner and outer notches 50′, 52′ are cut through the wear plate and, in particular, extend from the cover side 20a′ to the wear plate side 20b′ of the wear plate 20′. In FIG. 4, the protrusion 60 is bent or formed integrally with the wear plate.

FIG. 7 illustrates the wear plate 20 mounted to the back or wear plate cover 24 of the pump 10. The back cover 24 includes an integral inspection feature. U.S. Pat. No. 8,500,393 discloses a cover with the inspection feature and is hereby incorporated by reference, The disclosed wear plate can be incorporated into back covers of different configurations, including those not having inspection features. In addition, the wear plate 20 can be formed as an integral part of the back cover, i.e., not separately mounted via the studs 22.

FIG. 9 illustrates a general fiat layout of a wear plate constructed in accordance with one or more embodiments of the present invention. The wear plate 20 can be stamped or cut from flat stock. Depending on the application, the length L1 of the protrusion 60 can be selected in accordance with the pump application and impeller design. The angle θ, it is believed, is best kept at or below 45° (the angle at which the protrusion is bent towards the impeller). L2 is the dimension for the gap or tooth 48 between notches 46 and L3 is the width of the notches 46. L4 is the width selected for the grooves 50, 52, again dependent on application. It should be noted that the inner and outer grooves 50, 52 may have different widths.

The invention has been described in connection with a self-priming centrifugal pump. It should be noted that the invention contemplates use of the invention on any number of different types of centrifugal pumps, including but not limited to, self-priming, submersible, chopper and end suction solids handling pumps.

It is believed that the notches 46 and protrusion 60 shown in the figures inhibit stringy and fibrous materials from clinging to or wrapping around the wear plate and/or the impeller, thus reducing the chance of pump clogging by the material. With the disclosed configurations, the centrifugal pump can handle stringy or fibrous material without compromising the pump's ability to handle more conventional, large sized solids.

In addition, the present invention contemplates wear plates in which the outer groove 52 may be eliminated for some applications and also that there may be different numbers of inner and outer grooves and there may not be a need in some applications for a one-to-one correspondence between inner and outer grooves 50, 52. In addition, in the illustrated embodiment, the inner end 52a of the outermost groove is the same distance as measured radially as the outermost end of the inner groove. This relationship is shown in FIG. 9, where it can be seen that the innermost end segment 52a of the outer groove 52 and outermost end segment 50a of the inner groove 50 lie on a common annulus, indicated by the reference character 70. In other words, the groove ends 50a, 52a are in an overlapping relationship, The invention contemplates configurations where the respective ends of the grooves do not lie on a common circle or annulus and contemplates the forming of intermediate grooves on the wear plates for some applications. The invention also contemplates inner and outer grooves that do not have uniform depths across their radially extent. Finally, the invention contemplates a wear plate construction having multiple protrusions extending from the wear plate.

FIG. 10 illustrates a wear plate 20″ that is substantially similar to the wear plate 20 configuration shown in FIG. 4. However, in the configuration shown in FIG. 10, a hole or aperture 74 is formed in the protrusion 60″. This hole 74 is provided to facilitate bending of the protrusion 60″ when the wear plate is constructed of a relatively hard material which, if not for the aperture, would cause fracturing or other unwanted conditions to be created in the protrusion 60″ during the bending process.

Although the invention has been described with a certain degree of particularity, it should be understood that those skilled in the art can make various changes to it without departing from the spirit or scope of the invention as hereinafter claimed.

Claims

1. A centrifugal pump, comprising

a) a pump housing;

b) an impeller assembly mounted to said pump housing;

c) a wear plate mounted within said housing in a confronting relationship with an impeller forming part of said impeller assembly, said wear plate comprising: i) an annular wear plate portion defining an impeller side that confronts said impeller when said wear plate is mounted within said pump housing; ii) said annular portion defining an eye formed generally centrally in said portion and is substantially aligned with a rotational axis of said impeller; and iii) at least one protrusion extending from said eye toward said impeller.

2. The pump of claim 1 wherein said notches are wider in dimension than said tooth-like gaps.

3. The centrifugal pump of said claim 1 wherein said protrusion includes a prong extending at an angle from a mounting segment formed on said wear plate portion.

4. The centrifugal pump of claim 3 wherein said prong extends at an angle of substantially 45° with respect to a plane defined by said wear plate portion.

5. The centrifugal pump of claim 3 wherein said prong is welded to said mounting segment.

6. The centrifugal pump of claim 3 wherein said prong and mounting segment are integrally formed with said wear plate portion.

7. The centrifugal pump of claim 1 wherein said wear plate is attached to a wear plate cover which forms an assembly that is removably attached to said pump housing.

8. The centrifugal pump of claim 1 wherein said wear plate portion includes at least one radial groove.

9. The centrifugal pump of claim 8 wherein said wear plate portion includes a second radial groove, said one radial groove extending inwardly from an outer diameter of said wear plate and said second groove extends outwardly from said eye.

10. The centrifugal pump of claim 9 wherein said grooves have a predetermined depth but do not extend through said wear plate portion.

11. The centrifugal pump of claim 9 wherein said grooves extend through said wear plate portion.

12. The centrifugal pump of claim 1 wherein said protrusion includes an aperture to facilitate bending of said protrusion during its manufacturing process.

13. The centrifugal pump of claim 7 wherein said wear plate includes at least one stand-off by which said wear plate is attached to said wear plate cover.

14. The centrifugal pump of claim 1 wherein said annular wear plate portion defines a substantially planar wear plate surface confronting said impeller.

15. The centrifugal pump of claim 9 wherein said one radial groove has an inner end that is in a radial, overlapping relationship with an outer end of said second radial groove.

16. A wear plate for a centrifugal pump having a rotatable impeller located in a confronting relationship with said wear plate, said wear plate comprising:

a) an annular portion defining a wear plate surface that is in a confronting relationship with respect to said impeller when said wear plate is mounted within said centrifugal pump;

b) said annular portion defining an aperture that is axially aligned with an axis of rotation of said impeller when said wear plate is operatively positioned in said centrifugal pump; and

c) at least one protrusion extending toward said impeller from said annular portion, said protrusion extending at a predetermined angle with respect to a plane defined by said annular portion.

17. The wear plate of claim 6 wherein said notches are substantially wider in dimension than said tooth-like gaps.

18. The wear plate of claim 16 wherein said protrusion includes a prong that extends at a predetermined angle from said annular wear plate portion.

19. The wear plate of claim 18 wherein said angle is substantially 45° with respect to a plane defined by said wear plate portion.

20. The wear plate of claim 16 wherein said annular wear plate portion includes at least one groove that interrupts said wear plate surface.

21. The wear plate of claim 20 wherein said wear plate portion includes a second groove that interrupts said wear plate surface, said one groove extending inwardly from an outer diameter of said wear plate and said second groove extending outwardly from said aperture.

22. The wear plate of claim 21 wherein said grooves define recesses that are below said wear plate surface but do not extend through said wear plate.

23. The wear plate of claim 21 wherein said grooves extend through said annular wear plate portion.

24. The wear plate of claim 23 wherein said wear plate forms part of a wear plate assembly that can be removable mounted to said centrifugal pump.

25. The wear plate of claim 21 wherein said grooves extend in substantially the radial direction.

26. The wear plate of claim 16 wherein a periphery of said aperture is defined by at least one outwardly extending notch.

27. The wear plate of claim 16 wherein said periphery of said aperture is defined by a plurality of outwardly extending notches separated by tooth-like spacer gaps.

28. The centrifugal pump of claim 1 wherein said wear plate eye includes at least one peripheral notch.

29. The centrifugal pump of claim 1 wherein said wear plate eye includes a plurality of peripheral notches separate by tooth-like gaps.

30. The centrifugal pump of claim 1 wherein said centrifugal pump is of the self-priming variety.

31. The centrifugal pump of claim wherein said centrifugal pump is of the submersible variety.