Front side liner for a pump

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

FRONT SIDE LINER FOR A PUMPTechnical Field

[0001] The present invention relates to front side liners, in particular, a front side liner for a centrifugal slurry pump.Background Art

[0002] Centrifugal slurry pumps typically include a pump casing comprising a main casing, or volute, and one or more side liners. An impeller is mounted for rotation within the main casing about a rotation axis. The main casing has a discharge outlet and an inlet which is at one side of the main casing and coaxial with the impeller’s rotation axis. One of the side parts forms an intake and is often referred to as a front side liner, or a throatbush.

[0003] For centrifugal slurry pumps, the throatbush is where some of the most erosive wear occurs. To reduce the wear, the throatbush may be designed with an extra thickness and also may be cast in a particular material.

[0004] In some cases, for example if the thickness is more than standard, casting the throatbush in one piece is difficult because the alloys tend to shrink and crack during the cooling process.

[0005] Furthermore, the most erosive wear may occur on the throatbush between a surface of the impeller which faces towards an interior face of the throatbush at which a small clearance gap (sometimes referred to as a “nose gap”) exists to prevent rubbing of the rotating impeller against the throatbush. The wear at the nose gap occurs at a radial inner surface of the throatbush. In current designs, even if only the radial inner surface of the throatbush adjacent the “nose gap” wears, the entire throatbush is replaced resulting in increased wastage as the remainder of the throatbush is still within operating specifications.

[0006] It is among the objects of embodiments of the present invention to overcome or mitigate one or more of the above disadvantages or other disadvantages of the prior art, or to provide a useful alternative.Summary of the Disclosure

[0007] This summary is provided to introduce a selection of concepts that are further described in the detailed description below. This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter.

[0008] According to a first aspect there is provided a front side liner for a centrifugal slurry pump. The front side liner includes an inner part and an outer part. The inner part includes an annular body extending from a outer end towards an opposed inner end and a shoulder portion extending radially outward at the opposed inner end of the annular body. The shoulder portion has a inner surface and an opposed outer surface defining an axial thickness therebetween. The outer part is an annular ring having an inner diameter sized to receive the shoulder portion of the inner part. The outer part has an inner surface and an opposed outer surface defining an axial thickness therebetween which is equal to or smaller than the axial thickness of the shoulder portion. The shoulder portion of the inner part is receivable within the outer part to form the front side liner with the outer end of the annular body extending longitudinally pass the opposed outer surface of the outer part.

[0009] Preferably, the front side liner includes connecting means for connecting the outer and inner parts.

[0010] Preferably, the annular body is formed from a first material and the outer part is formed from a second material.

[0011] Preferebly, the front side liner includes an annular reinforcing ring which is securable to the outer surface of the outer part and the outer surface of the shoulder portion.

[0012] Preferably, the front side liner further includes a sealing element secured to a radial outer face of the outer part. The sealing element may further be securable to a radial outer face of the reinforcing ring.

[0013] According to a second aspect there is provided a front side liner assembly for a centrifugal pump. The front side liner assembly includes an inner part having an annularbody from an outer end towards an opposed inner end and a shoulder portion extending radially outward at the opposed inner end with an axial thickness. The front side lienr assembly further includes an outer part having an inner diameter sized to receive the shoulder portion of the inner part, and an axial thickness equal to or less than the axial thickness of the shoulder portion, wherein the shoulder portion of the inner part is receivable within the outer part to form the front side liner with the outer end of the annular body extending longitudinally outward pass the outer part. The front side liner also includes an annular reinforcing ring secured to an outer surface if the shoulder portion and an outer surface of the outer part for fastening the inner part and the outer part and a sealing element secured to an radial outer face of the outer part and a radial outer face of the annular reinforcing ring.

[0014] According to a third aspect there is provided a centrifugal pump. The centrifugal pump comprises a pump housing and an impeller positioned within the pump housing inner liner. The impeller is connected to a drive shaft which imparts rotation to the impeller about a rotation axis. The centrifugal pump also comprising a front side liner assembly according to the second aspect wherein the inner end of the front side lienr is positioned adjacent the impeller and wherein the reinforcing ring is secured to the pump housing.Brief Description of the Drawings

[0015] These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0016] Figure 1 shows an exploded view from the front of a front side liner in accordance with the present invention;

[0017] Figure 2 shows an exploded sectional view of the front side liner of Figure 1;

[0018] Figure 3 shows an exploded view from the rear of the front side liner of Figure 1;

[0019] Figure 4 shows a front view of the front side liner of Figure 1; and

[0020] Figure 5 shows a sectional view along line A-A of the front side liner as shown inFigure 4; and

[0021] Figure 6 shows a sectional view along line B-B of the front side liner as shown in Figure 4Detailed Description of Specific Embodiment

[0022] Figures 1, 2 and 3 show exploded views of a front side liner 10, or throatbush, in accordance with one embodiment of the present invention. The front side liner 10 extends longitudinally along an axis xx and includes an inner part 12, an outer part 14, a reinforcing ring 16 and a sealing element 18. In use, the front side liner 10 is housed within a pump housing (not shown) at the front end of the pump housing adjacent an inlet hole (not shown). The front side liner 10 is secured to a suction cover (not shown) of the pump housing (not shown) such that an inner end 24 of the front side liner 10 is orientated towards and adjacent an impeller (not shown) housed within the pump casing (not shown).

[0023] The inner part 12 includes an annular body 20 extending along axis xx from a outer end 22, which in use is orientated towards an outside of the pump casing (not shown), towards the opposed inner end 24, which in use is orientated towards an inside of the pump casing (not shown) and in use is adjacent the impeller (not shown). The inner part 12 further includes a shoulder portion 26, indicated by the portion shown in broken lines in Figure 2, extending radially outward from the annular body 20 at the opposed inner end 24. In this example embodiment, the inner part 12 includes a step formation 28 positioned adjacent an outer face 30, which is orientated towards the outer end 22, of the shoulder portion 26 and extends radially outward from the annular body 20. The step formation 28 has a smaller outer diameter relative to the outer diameter of the shoulder portion 26. The shoulder portion 26 includes an inner face 32, orientated towards the inner end 24, with an axial thickness, tl, measured between the inner 32 and outer faces 30.

[0024] The outer part 14 is an annular ring which is sized to receive the shoulder portion 26 of the inner part 12. In other words, the outer part 14 has an inner diameter dl sized to accommodate the shoulder portion 26 of the inner part 12. The outer part 14 has an outer face 34, orientated towards the outer end 22, and an inner face 36, orientated towards the inner end 24, withan axial thickness, t2, measured between the outer 34 and inner face 36 which is equal to or smaller than the axial thickness, tl, of the shoulder portion 26. In other words, the outer part 14 has a similar or smaller axial thickness than the shoulder portion 26 of the inner part 12 and as such only the shoulder portion 26, or a portion of the shoulderportion 26, is received within the outer part 14 with the remainder of the inner part extending longitudinally pass the outer part 14.

[0025] The annular body 20 of the inner part 12 furthermore defines a bore 38 which extends longitudinally through the annular part 20 along axis xx. The bore 38 includes a substantially cylindrical outer portion 40, having an inner diameter d2, and a profiled inner portion 42, having an inner diameter d3. The inner diameters, d2 and d3, may be determined by the application, or slurry type. It is to be appreciated that the profiled inner portion 42 may be substantially cylindrical, frusto-conical shaped or any alternative shape. The diameter d3 of the profiled inner portion 42 may be small than the diameter d2 of the outer portion 40 such that an inner step formation 43 is defined between the inner 42 and outer portions 40. Advantageously, the outer part 14 may accommodate inner parts 12 having different inner diameters and or different profiled inner portions (eg reduced eye or standard eye) for different duty conditions.

[0026] The inner part 12 and the outer part 14 can be cast in different alloys, or rubber moulded to suit different wear goals. For example, due to internal recirculation and variable duty operating points, the inner part 12 may experience more wear and different wear patterns than the outer part 14.

[0027] Additionally, it is possible to independently replace either the inner 12 or outer parts 14 if, for example one wears quicker than the other.

[0028] The reinforcing ring 16 is secured to the outer face 30 of the shoulder portion 26 and the outer face 34 of the outer part 14. In the example embodiment with the axial thickness t2 of the outer part 14 being smaller than the thickness tl of the shoulder portion 26, the reinforcing ring 22 includes a profiled inner wall 44 which faces and sits against the outer faces 30 and 34 of the shoulder portion 26 and the outer part 14.

[0029] The inner part 12 includes a plurality of openings 46 located in the outer face 30 of the shoulder portion 26. The plurality of openings 46 are circumferentially spaced around the bore 38. The plurality of openings 46 may each be arranged to threadely receive a spacer 48 (shown in Figure 5). Each spacer 48 may further be arranged to threadely receive afastener 50 to secure the reinforcing ring 16 to the inner part 12. It is to be appreciated that spacers with varying axial lengths could be utilised. Advantageously, the two part throatbush and the use of spacers having varying axial lengths allow for the inner part 12 to be adjusted forward, in other words inwards so that a gap between the innermost point of the inner part and the impeller housed within the pump casing is reduced or maintained irrespective of wear, independently of the outer part 14. Adjusting the inner part 12 forward furthermore causes the recirculation to decrease which also decreases wear.

[0030] The outer part 14 includes a plurality of protrusions 52 which are circumferentially spaced and extend from the outer face 34 of the outer part 14. The reinforcing ring 16 may include corresponding recesses 54 into which the plurality of protrusions fit 52. The plurality of protrusion 52 include treaded apertures 56 into which fasteners 58 are threadely received to secure the reinforcing plate 16 to the outer part 14.

[0031] In use, the reinforcing ring 16 includes a plurality of apertures 60 in an outer face 62 of the reinforcing ring into which fasterners are threadely received to secure to a cover plate, and subsequently the inner part, outer part, and reinforcing ring to the pump casing or cover plate.

[0032] The sealing member, in this example embodiment a rubber seal 18, is secured or moulded to a radially outer surface 64 of the outer part 14 and an radially outer surface 66 of the reinforcing ring 16 using hot press moulding to ensure bonding between the outer part 14 and the reinforcing ring 16 and avoid any leakage. The sealing member 18 furtermore creates a fluid tight seal between the outer part 14 and reinforcing ring 16 and the pump casing (not shown).

[0033] As opposed to current front side liners where the reinforcing plate, sealing member and outer part are of unitary construction the current invention provides a front side liner where these components are separately formed which allows a throatbush having a thickness more than standard to be casted as separate pieces (inner and outer parts) to ellivate the problems faces due to the alloys tendency to shriek and crack during the cooling process. The separate components of the front side liner furthermore allows the different componentsto be constructed from different materials and individual replacement of the separate components.

[0034] The foregoing describes only some embodiments of the inventions, and alterations, modifications, additions and / or changes can be made thereto without departing from the scope of the disclosed embodiments, the embodiments being illustrative and not restrictive.List of Reference Numerals10 front side liner12 inner part14 outer part16 reinforcing ring18 sealing element20 annular body of inner part22 outer end24 inner end26 shoulder portion of inner part28 step formation of inner part30 outer face of shoulder portion32 inner face of shoulder portion34 outer face of outer part36 inner face of outer part38 bore of annular body40 outer portion of bore42 profiled inner portion of bore43 step formation of bore44 profiled inner wall of reinforcing ring46 opening in inner part48 spacers50 fastemers52 protrusions of outer part54 recesses of reinforcing ring56 apertures in protrusions58 fasteners60 apetures in reinforcing ring62 outer face of reinforcing ring64 radialy outer surface of outer part66 radially outer surface of reinforcing ring

Claims

CLAIMS1. A front side liner for a centrifugal slurry pump, the front side liner including: an inner part having an annular body extending from an outer end towards an opposed inner end and a shoulder portion extending radially outward at the opposed inner end with an axial thickness; and an outer part having an inner diameter sized to receive the shoulder portion of the inner part, and an axial thickness equal to or less than the axial thickness of the shoulder portion, wherein the shoulder portion of the inner part is receivable within the outer part to form the front side liner with the outer end of the annular body extending longitudinally outward pass the outer part.

2. The front side liner of claim 1, further including an annular reinforcing ring for fastening the inner part and the outer part.

3. The front side liner of claim 1, wherein the annular reinforcing ring is secured to an outer surface if the shoulder portion and an outer surface of the outer part.

4. The front side liner of claim 1, wherein the inner part is formed from a first material and the outer part is formed from a second material.

5. The front side liner of any one of the preceding claims, further including a sealing element secured to an radial outer face of the outer part.

6. The front side liner of claim 5, wherein the sealing element is further secured to an radial outer face of the fastening plate.

7. An inner part for a front side liner for a centrifugal slurry pump, the inner part having an annular body having a central axis and a shoulder portion with an axial thickness, wherein the shoulder portion is configured to engage an outer part to form the front side liner.

8. A front side liner assembly for a centrifugal slurry pump, the front side liner assembly including:an inner part having an annular body extending from an outer end towards an opposed inner end and a shoulder portion extending radially outward at the opposed inner end with an axial thickness; an outer part having an inner diameter sized to receive the shoulder portion of the inner part, and an axial thickness equal to or less than the axial thickness of the shoulder portion, wherein the shoulder portion of the inner part is receivable within the outer part to form the front side liner with the outer end of the annular body extending longitudinally outward pass the outer part; an annular reinforcing ring secured to an outer surface if the shoulder portion and an outer surface of the outer part for fastening the inner part and the outer part; and a sealing element secured to an radial outer face of the outer part and a radial outer face of the annular reinforcing ring.

9. A centrifugal slurry pump, comprising: a pump housing; an impeller positioned within the pump housing inner liner, the impeller being connected to a drive shaft which impart rotation to the impeller about a rotation axis; and the front side liner assembly of claim 8 wherein the inner end of the front side liner is positioned adjacent the impeller and wherein the reinforcing ring is secured to the pump housing.