AU623891B2

AU623891B2 - Means for reducing passageway wear

Info

Publication number: AU623891B2
Application number: AU35853/89A
Authority: AU
Inventors: Nicholas Subotsch
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-31
Filing date: 1989-05-31
Publication date: 1992-05-28
Anticipated expiration: 2009-05-31
Also published as: AU3585389A

Description

623 89 COMMONWEALTH OF AUSTRALIA P at en ts A ct 1 9 52 COMPLETE SPECIFICATION (original) FOR OFFICE USE Application Number: P18543 Class Lodged: 31 May, 1988 Complete Specification Lodged: Accepted: Published: Int. Class Priority: Related Art: p. 001978 3 10589 C t t TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: NICHOLAS SUBOTSCH oD-f-1-4--A-Me-l-v-i-l-e-P-a-r.de,-Como,, in -tlie-Sta-e-)fJ es-exA -usL: ala, mmonwea-l-t-of-Au-taJ-l-a.

Actual Inventor: NICHOLAS SUBOTSCH

RAO

E C.

104 Address for Service:- Cl- Wray Associates Primary Industry House 239 Adelaide Terrace Perth Western Australia 6000.

for the invention entitled: for Reducing Passageway Wear" 4'1 *full description *of this method of performing it known -2 THIS INVENTION relates to means for reducing passageway wear in passageways for causing deviation of a fluid flow which has particular utility in the passage of erosive or ^abrasive fluids.

In the passage of erosive or abrasive fluids such as slurries in mining operations, a major difficulty which is tolerated in the industry is the replacement of various components such as pumps and bends in pipelines which cause a deviation in the flow of the slurry or the like.

Consequently, these components comprise surfaces which are *0 0 opposed to the general direction of fluid flow and so are e.

S- subject to wear due to the abrasive, or erosive nature of l the fluid more so than other surfaces of the component 1 which do not confront the fluid flow to the same degree.

One particular example of this wear arises in the use of centrifical slurry pumps, whereby slurry is directed centrifugally by an impeller within a circular chamber and is discharged tangentially from the chamber through an i. .r outlet port for conveyance down a pipeline. At the junction of the outlet port and the circular chamber, a cut water point is defined which essentially divides the slurry flow into two paths, the principal path being along the outlet port, and the other path being of a proportionally much smaller size to impede the slurry returning to the impeller chamber.

As a result of the deviation in flow of the slurry, the cut water point directly confronts oncoming slurry to divide the same, depending upon its spatial relationship with respect to the point, along one or the other paths.

As a result of the highly abrasive nature of the slurry, the cutwater point is subject to extreme wear.

Therefore, it is usual in the design of slurry pumps of this nature that the cutwater point is reinforced by the provision of additional material to increase the time ^Sl' 1 i%^Si i% v 3 taken for the cutwater point to inevitably wear away to a point where the efficiency of the pump is inadequate and/ or a hole is formed in the wall of the pump in the region of the cutwater point.

It is an object of the present invention to provide means for reducing the rate of wear upon opposing portions of a wall of a passageway which cause a deviation in fluid flow, and which confront the fluid flow to achieve the deviation.

In accordance with one aspect of the present invention, there is provided in a passageway for causing deviation of a fluid flow therein, means disposed along said passageway for reducing wear along an opposing portion of the passageway wall disposed to confront said fluid flow .:during said deviation, said means comprising a contoured :i :outer surface along a portion of said passageway wall :opposite to said opposing portion to define a bore of said passageway expanding in the direction of said fluid flow proximate to said opposing portion so as to create low pressure region acting upon said fluid flow prior to and directly opposite to said opposing portion thereby biasing fluid flow away from said opposing portion to reduce wear thereof.

The invention will be better understood in the light of othe following description of two specific embodiments.

"The description is made with reference to the accompanying drawings wherein:- Figure 1 is a sectional view of a centrifugal slurry pump incorporating the means of the invention in accordance with the first embodiment; and Figure 2 is a sectional view of an elbow in a pipeline 4 showing the means of the invention in accordance with the second embodiment.

The first embodiment is directed to a centrifugal slurry pump 11 comprising a circular chamber 13 which houses an impeller generally identified at 15, a tangential outlet port 17 and means 19 for reducing wear.

As shown on the drawings, the outlet port 17 is formed contiguously with the outside of the chamber 13 to define an inner cutwater point 21 at the junction between the 1 t:'t touter wall of the chamber and the inner wall of the outlet I l .port. An inlet port (not shown) is disposed centrally of 1 the chamber 13 for introducing slurry into the pump which is subsequently directed centrifugally by the impeller I The outlet port 17 forms a passageway, from the chamber 13 'for discharge of slurry and the cutwater point 21 defines I C t C t an opposing portion of the passageway wall which is disposed to confront the slurry flow and divide the same "into two paths. The main path indicated by arrow 23 directs slurry flow tangentially from the chamber 13 out through the outlet port 17. The other path indicated by arrow 25 returns a very small portion of the centrifical slurry flow back to the chamber 13. Consequently, the cutwater point 21 is subjected to extreme wear as a result Sf the abrasive erosive effect of the slurry.

The means 19 is disposed upon a portion 27 of the passageway wall opposite to the opposing portion or cutwater point 21 of the passageway wall. The means 19 comprises' a ontoured outer surface 29 and projects inwardly of the portion 27 of the passageway wall to define a bore 31 of the passageway which widens in crosssection progressively in the direction of the slurry flow Stproximate to athe opposing portion or ctwater point. 21 of i the passageway wall. Thus, as shown in the drawings, the contoured surface 29 of the means initially projects inwardly of the passageway from a point upstream of the cutwater point 21 to define a peak 33 also disposed upstream of the cutwater point 21, and which subsequently tapers outwardly of the passageway to return to the portion 27 of the passageway wall toward the region of the outlet port 17. In this manner, slurry flow proceeding along the path 23 is subject to a semi venturi effect by the creation of a low pressure region subsequent to passing the peak 33 in the expanding bore 31 proximate to

I

I t the portion 27 of the passageway wall so causing slurry K flow to be biased towards the outer portion 27 of the wall St in preference to the cutwater point 21. Consequently, t t this biasing effect upon the slurry flow reduces the pressure of slurry flow confronting the cutwater point and S hence reduces wear of the same.

,The second embodiment is directed towards a passageway C. C within an elbow 35 of a pipeline for conveying an abrasive or erosive fluid, which similarly causes a deviation of the fluid from its inertial direction.

S As shown at Figure 2 of the drawings, the elbow i comprises a passageway wall 37 having an opposing portion 37a along its outer side with respect to the passageway ,0which is disposed to confront the fluid flow during its deviation along the elbow, a portion 37b of the passageway wall opposite to the opposing portion 37a, and means 39 projecting inwardly from the portion 37b.

In this arrangement, the means 39 defines an expanding bore 41 of the passageway immediately after the peak 43 of the contoured outer surface thereofwhich is proximate to sthe opposing wall 37a l of ;the *'passageway. Consequently, the semi venturi effect created by the expanding bore 6 41 causes a reduction in pressure in the region of the bore adjacent to the portion 37b of the passageway to bias fluid flow away from the opposing portion 37a of the passageway wall, and so reducing wear which would otherwise proliferate therealong.

It should be appreciated that the scope of the present invention is not limited to the particular embodiments hereindescribed. In particular, the means 19 for reducing wear along the opposing portion of the passageway wall can be formed either integrally with the wall during its formation or alternatively, the means may be formed discretely for subsequent insertion into the passageway and affixture to the passageway wall by welding or we bonding.

r V t X 4 I t

Claims

1. In a passageway for causing deviation of a fluid flow therein, means disposed along said passageway for reducing wear along an opposing portion of the passageway wall *I 'disposed to confront said fluid flow during sa:id deviation, said means comprising a contoured outer surface along a portion of said passageway wall opposite to said opposing portion to define a bore of said passageway expanding in the direction of said fluid flow proximate to V said opposing portion so as to create a low pressure region acting upon said fluid flow prior to and directly opposite to said opposing portion thereby biasing fluid flow away from said opposing portion to reduce wear thereof and increase flow efficiency.

2. In an outlet passageway for a centrifugal pump casing, means disposed along said passageway for reducing wear of the cut water disposed to confront output fluid Sflow at the junction between said outlet passageway and said casing, said means comprising a contoured outer surface along a portion of said passageway wall approximately opposite to said cutwater to define a bore of said passageway expanding in the direction of said fluid flow proximate to said cutwater so as to create a low pressure region acting upon said fluid flow prior to and directly opposite to said cutwater thereby biasing fluid flow away from said cutwater to reduce wear thereof and increase flow efficiency of the centrifugal pump.

3. Means disposed in a passageway substantially as herein described with reference to the accompanying i drawings. DATED this TENTH day of JULY 1991. NICHOLAS SUBOTSCH A Applicant. ASSOCIATES D Pe:hb, Western 'stralia, P :Znt Attorneys for the Applicant.