Centrifugal separator with a separate strip insert mounted in the bowl Number:7,144,360 from the United States Patent and Trademark Office (PTO) owispatent

Title: Centrifugal separator with a separate strip insert mounted in the bowl

Abstract: A centrifuge concentrator bowl includes a plurality of fluidized recesses at axially spaced positions along the peripheral wall. Each recess is defined by two side walls which has water injection holes for fluidizing materials collecting in the recess. Some of the recesses are at least partly defined by a removable insert member arranged to be attached to a suitable mounting on the wall of the bowl. Each insert member includes a face portion defining a surface facing toward the axis of the bowl for engaging the slurry and preventing wear. The face portion may include a side portion on one side or both sides located radially inwardly of a rib on a respective side of the recess and at least partly covering the rib so as to prevent the slurry from contacting the rib and causing wear to the rib.

Patent Number: 7,144,360 Issued on 12/05/2006 to Zonneveld,   et al.

---

Inventors:	Zonneveld; Edwin John William (Fort Langley, CA), Knabe; Kurt (Coquitlam, CA), Knelson; Brett Robert Henry (Langley, CA)
Assignee:	Knelson Patents Inc. (Langley, unknown)
Appl. No.:	11/103,636
Filed:	April 12, 2005

---

Current U.S. Class:	494/29 ; 494/80
Current International Class:	B04B 11/04 (20060101)
Field of Search:	494/23,27-30,56,63,80,38,43,44-45,64 209/453 210/360.1,380.1

---

References Cited [Referenced By]

---

U.S. Patent Documents

	459197		September 1891		Bodge
	459858		September 1891		Seymour
	489101		October 1893		Seymour
	556567		March 1896		Waring
	726948		May 1903		Land
	917123		April 1909		Peck
	957478		May 1910		Simpson
	980001		December 1910		Ponten
	981679		January 1911		Peck
	1011078		December 1911		Peck
	1012097		December 1911		Peck
	1283846		November 1918		Mark et al.
	1322139		November 1919		Schifferle
	1473421		November 1923		Eccleston
	1557672		October 1925		Doerner
	1594501		August 1926		Eccleston
	1599502		September 1926		Thomassen
	1684870		September 1928		Lewis
	1718547		June 1929		Eccleston
	1750860		March 1930		Rawlings
	1853249		April 1932		Ainlay
	1882389		October 1932		MacIsaac
	1935547		November 1933		Dryhurst
	1988500		January 1935		Lack
	2022926		December 1935		Schlank
	2112099		March 1938		Mck Ballou et al.
	2132195		October 1938		Stirn
	2179807		November 1939		Asmussen
	2230013		January 1941		Pecker
	2272675		February 1942		Knudsen
	2472475		June 1949		Hamilton
	2782925		February 1957		Morton
	3152074		October 1964		Fontein et al.
	3256993		June 1966		Siepe et al.
	3366318		January 1968		Steimel
	3963175		June 1976		Daubman et al.
	4279741		July 1981		Campbell
	4286748		September 1981		Bailey
	4361480		November 1982		Corbus et al.
	4533344		August 1985		Gunnewig
	4608040		August 1986		Knelson
	4776833		October 1988		Knelson
	4846781		July 1989		Knelson
	4983156		January 1991		Knelson
	5087127		February 1992		Knelson
	5222933		June 1993		Knelson et al.
	5230797		July 1993		Knelson
	5338284		August 1994		Knelson
	5354256		October 1994		Knelson
	5368541		November 1994		Knelson
	5372571		December 1994		Knelson et al.
	5421806		June 1995		Knelson et al.
	5462513		October 1995		McAlister
	5586965		December 1996		Knelson
	5601524		February 1997		Knelson
	5601532		February 1997		Knelson
	5713826		February 1998		West
	5728039		March 1998		Knelson
	5895345		April 1999		Knelson
	6095965		August 2000		Eiderman et al.
	6149572		November 2000		Knelson
	6796934		September 2004		McAlister et al.
	6869389		March 2005		Mackel et al.
	6962560		November 2005		Grewal
	6986732		January 2006		Zonneveld et al.
	6997859		February 2006		Peacocke et al.
	2004/0121892		June 2004		Zonneveld et al.
	2004/0132601		July 2004		Peacocke et al.
	2005/0026766		February 2005		Grewal

Foreign Patent Documents

	22055		Apr., 1936		AU
	2085064		Jun., 1993		CA
	2443239		Mar., 2005		CA
	2031350		Dec., 1971		DE
	58-24366		Feb., 1983		JP
	11-276110		Oct., 1999		JP

Primary Examiner: Cooley; Charles E.
Attorney, Agent or Firm: Battison; Adrian D. Williams; Michael R. Dupuis; Ryan W.

---

Parent Case Text

---

This application claims priority under 35 U.S.C. 119 from Provisional Application 60/637,751 filed Dec. 22, 2004.

---

Claims

---

The invention claimed is:

1. A set of recess insert members: for use in a centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes: a feed duct for feeding the slurry into the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth; a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth; a bowl; the bowl having a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth; the bowl having a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass, when fed from the supply duct, so that the heavier particulate materials collect in the recesses; each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall; the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall; at least some of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid supply and at least one liquid entry opening extending from the supply into the recess at or closely adjacent the base of the recess; each of the recess insert members comprising an elongate body shaped to extend only over a part of the height of the peripheral wall such that the set of recess insert members can be arranged at axially spaced positions in the bowl; each of the recess insert members being shaped to extend around at least a part of the annular periphery of the peripheral wall; each of the recess insert members being formed from a resilient material: each of the recess insert members having at least one abutment element thereon for engaging a respective one of a plurality of co-operating elements of the bowl for holding the recess insert member in the bowl during rotation of the bowl; the abutment element and the cooperating element being arranged such that the recess insert member is readily removable and replaceable; each of the recess insert members being shaped to define an upper side wall of one of the recesses and a lower wall of a next adjacent one of the recesses with a rib therebetween such that, when two of the recess insert members are mounted in said axially spaced positions side by side, the recess insert members cooperate to define said one of the recesses therebetween.

2. The set of recess insert members according to claim 1 wherein the abutment member of each of the recess insert members comprises a channel around an outer face on the recess insert member for receiving an annular band of the peripheral wall of the bowl.

3. The set of recess insert members according to claim 1 wherein each of the recess insert members is annular and extends around the full periphery of the bowl to define butting ends of the recess insert member.

4. A centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes a feed duct for feeding the slurry into the bowl during rotation of the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth and a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth the bowl comprising a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth; and a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass when fed from the supply duct; each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall; the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall; at least one of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid supply and at least one liquid entry opening extending from the supply into the recess at or closely adjacent the base of said one of said recesses; and at least one recess insert member mounted in a respective one of the recesses in the bowl; the recess insert member being shaped to extend only over a part of the height of the peripheral wall; the recess insert member being elongate and shaped to extend around at least a part of the annular periphery of the peripheral wall; the recess insert member being formed from a resilient material; the recess insert member having at least one abutment element thereon for engaging a co-operating element of the bowl for holding the recess insert member in the bowl during rotation of the bowl; the abutment element and the cooperating element being arranged such that the recess insert member is readily removable and replaceable; wherein the recess insert member includes a side portion arranged to be located radially inwardly of a respective one of the ribs on a respective side of a respective one of the recesses and at least partly covering the respective one of the ribs fib so as to prevent the slurry from contacting the respective one of the ribs and causing wear to the respective one of the ribs.

5. The centrifuge bowl according to claim 4 wherein of the recess insert member includes a radially inwardly facing surface which is arranged to extend across the recess and onto the side portion.

6. The centrifuge bowl according to claim 5 wherein the surface is shaped to define at least one surface recess radially inwardly of the recess.

7. The centrifuge bowl according to claim 4 wherein the recess insert member includes two side portions each on a respective side of the recess and each arranged to cover a respective one of the ribs on opposite sides of the recess.

8. The centrifuge bowl according to claim 4 wherein the side portion of the recess insert member has an edge at an axial end thereof and an edge surface extending from the edge to a next adjacent recess and wherein the edge surface is arranged to be substantially contiguous with a side wall of the next adjacent recess.

9. The centrifuge bowl according to claim 4 wherein the respective one of the ribs has a radially inwardly facing surface and wherein the side portion of the recess insert member has a radially outwardly facing surface arranged to be in contact with and resting against the radially inwardly facing surface of the respective one of the ribs.

10. The centrifuge bowl according to claim 4 wherein the recess insert member is annular and extends around the full periphery of the respective one of the recesses to fill the respective one of the recesses to define butting ends of the recess insert member.

11. The centrifuge bowl according to claim 4 wherein the recess insert member has side walls arranged to be in contact with and resting against the side walls of the respective one of the recesses.

12. A centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes a feed duct for feeding the slurry into the bowl during rotation of the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth and a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth, the bowl comprising a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth; the peripheral wall of the bowl having attached thereto a plurality of axially spaced annular bands each arranged for mounting thereon an abutment element of a respective one of a plurality of recess insert members, the abutment element and the annular band being arranged such that the recess insert member is readily removable and replaceable.

13. The bowl according to claim 12 wherein the annular band defines shoulders for engaging into a channel on the recess insert member.

14. The bowl according to claim 12 wherein there is provided a liquid supply for a fluidizing liquid injection system for fluidizing the materials in the respective recess which includes a channel defined between an exterior of the at least one recess insert member and an interior of the peripheral wall, the channel passing through the annular bands.

15. A centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes a feed duct for feeding the slurry into the bowl during rotation of the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth and a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth, the bowl comprising a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth; and a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass when fed from the supply duct; each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall; the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall; at least one of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid supply and at least one liquid entry opening extending from the supply into the recess at or closely adjacent the base of said one of said recesses; at least a part of at least one side wall of at least one of the recesses being formed from a recess insert member mounted in the bowl; the recess insert member being elongate and shaped to extend only over a part of the height of the peripheral wall; the recess insert member being elongate and shaped to extend around at least a part of the annular periphery of the peripheral wall; the recess insert member being formed from a resilient material; the recess insert member having at least one abutment element thereon for engaging a cooperating element of the bowl for holding the recess insert member in the bowl during rotation of the bowl; the abutment element and the cooperating element being arranged such that the recess insert member is readily removable and replaceable.

16. The centrifuge bowl according to claim 15 wherein there are at least two recess insert members arranged at axially spaced locations where one defines the lower side wall of a recess and a second defines the upper side wall of a recess.

17. The centrifuge bowl according to claim 16 wherein there is provided a perforated insert member mounted in the recess between the two recess insert members at a position therein so as to define a channel between the side walls, inwardly of the base and outwardly of the perforated insert member within which the fluidizing liquid from the liquid entry opening can flow within the recess, the perforated insert member having an inwardly facing surface which spans the space between the side walls at the perforated insert member so as to confine the materials within the volume of the recess defined by the side walls and inwardly of the inwardly facing surface of the perforated insert member, the perforated insert member having an array of fluid injection holes defined therethrough which allow the injection of jets of fluidizing liquid from the channel through the perforated insert member into the volume.

18. The centrifuge bowl according claim 15 wherein the recess insert member is shaped to define an upper side wall of one recess and a lower wall of a next adjacent recess with a slurry engaging surface of a rib therebetween.

19. The centrifuge bowl according to claim 18 wherein the slurry engaging surface is shaped with at least one angularly extending recess thereon for contacting and changing slurry flow over the surface.

20. The centrifuge bowl according to claim 18 wherein the recess insert member includes a layer of a material attached thereto at the slurry engaging surface which is of increased wear resistance relative to a main material from which the recess insert member is formed.

21. The centrifuge bowl according to claim 20 wherein the layer is attached by adhesive.

22. The centrifuge bowl claim 15 wherein the peripheral wall of the bowl has attached thereto, for the recess insert member, a mounting member extending inwardly from the wall for engaging an abutment member on the recess insert member.

23. The centrifuge bowl according to claim 22 wherein the mounting member comprises an annular band carried on the peripheral wall.

24. The centrifuge bowl according to claim 23 wherein the annular band defines shoulders for engaging into a channel on the recess insert member.

25. The centrifuge bowl according to claim 15 wherein the liquid supply of the fluidizing liquid injection system for fluidizing the materials in said at least one of the recesses includes a channel defined between an exterior of the at least one recess insert member and an interior of the peripheral wall.

26. The centrifuge bowl according to claim 15 wherein the recess insert member is annular and extends around the full periphery of the bowl to define butting ends of the recess insert member.

27. A centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes a feed duct for feeding the slurry into the bowl during rotation of the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth and a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth, the bowl comprising a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth; and a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass when fed from the supply duct; each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall; the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall; at least one of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid supply and at least one liquid entry opening extending from the supply into the recess at or closely adjacent the base of said one of said recesses; and at least two recess insert members mounted in the bowl at axially spaced positions along the bowl and arranged such that at least a part of at least one side wall of at least one of the recesses is formed from a respective one of the recess insert members; each recess insert member being shaped to extend only over a part of the height of the peripheral wall; each recess insert member being elongate and shaped to extend around at least a part of the annular periphery of the peripheral wall; each recess insert member being formed from a resilient material; each recess insert member having at least one abutment element thereon for engaging a respective one of at least two co-operating elements of the bowl for holding the recess insert member in the bowl during rotation of the bowl; the abutment element and the co-operating element being arranged such that the recess insert members are readily removable and replaceable; wherein one of the recess insert members defines a lower side wall of one of the recesses and a second of the recess insert members defines an upper side wall of said one of the recesses.

28. The centrifuge bowl according to claim 27 wherein there is provided a perforated insert member mounted in said one of the recesses defined between the two recess insert members at a position therein so as to define a channel between the side walls, inwardly of the base and outwardly of the perforated insert member within which the fluidizing liquid from the liquid entry opening can flow within said one of the recesses, the perforated insert member having an inwardly facing surface which spans the space between the side walls at the perforated insert member so as to confine the materials within the volume of said one of the recesses defined by the side walls and inwardly of the inwardly facing surface of the perforated insert member, the perforated insert member having an array of fluid injection holes defined therethrough which allow the injection of jets of fluidizing liquid from the channel through the perforated insert member into the volume.

29. The centrifuge bowl according to claim 28 wherein the recess insert member is annular and extends around the full periphery of the bowl to define butting ends of the recess insert member.

30. The centrifuge bowl claim 27 wherein the co-operating element of the bowl, for each of the recess insert members, comprises a mounting member attached to the peripheral wall and extending radially inwardly from the peripheral wall for engaging the abutment member on the recess insert member.

31. The centrifuge bowl according to claim 30 wherein the mounting member for each of the recess insert members comprises an annular band carried on the peripheral wall for engaging into a channel on the recess insert member.

32. A centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes a feed duct for feeding the slurry into the bowl during rotation of the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth and a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth, the bowl comprising a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth; and a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass when fed from the supply duct; each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall; the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall; at least one of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid supply and at least one liquid entry opening extending from the supply into the recess at or closely adjacent the base of said one of said recesses; and a plurality of recess insert members mounted in the bowl at axially spaced positions along the bowl and arranged such that at least a part of at least one side wall of at least one of the recesses is formed from a respective one of the recess insert members; each recess insert member being shaped to extend only over a part of the height of the peripheral wall; each recess insert member being elongate and shaped to extend around at least a part of the annular periphery of the peripheral wall; each recess insert member being formed from a resilient material; each recess insert member having at least one abutment element thereon for engaging a respective one of a plurality of cooperating elements of the bowl for holding the recess insert member in the bowl during rotation of the bowl; the abutment elements and the cooperating elements being arranged such that the recess insert members are readily removable and replaceable; wherein each recess insert member is shaped to define an upper side wall of one of the recesses and a lower wall of a next adjacent one of the recesses with a rib therebetween such that two side by side recess insert members cooperate to define said one of the recesses therebetween.

33. The centrifuge bowl claim 32 wherein the co-operating element of the bowl, for each of the recess insert members, comprises a mounting member attached to the peripheral wall and extending radially inwardly from the peripheral wall for engaging the abutment member on the recess insert member.

34. The centrifuge bowl according to claim 33 wherein the mounting member for each of the recess insert members comprises an annular band carried on the peripheral wall for engaging into a channel on the recess insert member.

35. The centrifuge bowl according to claim 32 wherein the recess insert member is annular and extends around the full periphery of the bowl to define butting ends of the recess insert member.

---

Description

---

This invention relates to a centrifugal separator of the type having a plurality of axially spaced annular recesses on a peripheral wall of a rotatable bowl.

In U.S. Pat. Nos. 4,608,040, 4,776,833, 5,222,933, 5,421,806, 5,230,797 and 5,338,284 of Benjamin Knelson and now assigned to the present Assignee discloses a number of different arrangements of centrifugal separator of the type including a rotatable bowl having a peripheral wall of generally frusto-conical shape on which is provided a plurality of axially spaced, annular recesses. The particulate material containing fractions of different specific gravity to be separated is fed in slurry form through a feed duct to a position at or adjacent a base of the bowl so that the feed materials pass over the peripheral wall with heavier particulate materials collecting in the annular recesses while lighter particulate materials escape from the bowl through the open mouth. In the above patents, all of the annular recesses are fluidized by the injection of fluidizing water through holes in the peripheral wall at the respective recesses thus acting to fluidize the collecting material within the recesses.

A further arrangement is disclosed in U.S. Pat. No. 5,586,965, issued Dec. 24th, 1996 of the above inventor in which the number of recesses is reduced and a frusto-conical lead-in section of the bowl is provided which is free from fluidized recesses so that the feed material is deposited onto the lead-in section and flows over that lead-in section prior to reaching the first annular recess.

In all cases the fluidized recesses are formed by providing drilled holes through the base of the recess in the manner disclosed in U.S. Pat. Nos. 4,608,040 and 5,230,797 above. This provides requirements on the construction and location of the holes which can lead to blockage and can limit the ability to tailor the arrangements to the best processing parameters.

In Australian Published Application 22,055/35 published 2.sup.nd Apr. 1935 by Macnicol is disclosed a centrifuge bowl where the recesses on the peripheral wall are fluidized by injecting water through the wall and where the holes through the wall are covered by a band of screen material applied on the inside surface of the wall. The purpose of this screen is not explained. This device has not achieved commercial success and the disclosure has been long abandoned as a workable arrangement.

In Canadian Patent Application 2,085,064 of the above inventor published 12.sup.th Jun. 1993 is disclosed an arrangement using the machine having conventional V-shaped recesses of the type disclosed in the above patents in which an annular insert of a screen mesh material is placed in each recess at a position spaced from the base of the recess and spaced from the mouth of the recess with the intention of forming a recess which is shallower than the conventional recess. The shallow recesses are intended to form a concentrate which is richer than that of a conventional concentrator since less material is collected in each recess and it is stated that the machine is intended to be used as a "final separator" in a process of repeated concentration. Thus the inventor intended that in a line of conventional separators, the last would be modified from the conventional by the addition the mesh material inserts to form the special shallow recesses for the last separator only.

In Canadian Application 2,443,239 filed Oct. 15, 2003 by the present assignees and published in December 2003 is disclosed an arrangement of the above type in which an insert ring is provided which is inserted into at least some of the recesses to define a base of the recess with the ring being perforated and spaced from the bottom of the recess. The ring is thus a replaceable item within the bowl.

Machines of this type have grown bigger and the tonnage capacities have increased which has lead to an increase in the associated wear problems. The concentrating bowl surface speed increases with the square root of the cone diameter for a constant g-force operation while wear rates are typically proportional to the velocity squared so that the wear rate is directly proportional to the cone diameter.

SUMMARY OF THE INVENTION

It is one object of the present invention to provide an improved centrifugal separator of the above general type in which wear problems are reduced by providing a replaceable insert.

According to a first aspect of the invention, therefore, there is provided a centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes a feed duct for feeding the slurry into the bowl during rotation of the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth and a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth, the bowl comprising

a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth;

and a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass when fed from the supply duct;

each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall;

the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall;

at least some of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid supply and at least one liquid entry opening extending from the supply into the recess at or closely adjacent the base of the recess;

at least a part of at least one side wall of at least one of the recesses being formed from a recess insert member mounted in the bowl;

the recess insert member being elongate and shaped to extend only over a part of the height of the peripheral wall;

the recess insert member being elongate and shaped to extend around at least a part of the annular periphery of the peripheral wall;

the recess insert member being formed from a resilient material;

the recess insert member having at least one abutment element thereon for engaging a cooperating element of the bowl for holding the recess insert member in the bowl during rotation of the bowl;

the abutment element and the cooperating element being arranged such that the recess insert member is readily removable and replaceable.

In one embodiment described in more detail hereinafter, where the recesses are formed on the bowl wall by attached insert members, there are at least two recess insert members arranged at axially spaced locations where one defines the lower side wall of a recess and a second defines the upper side wall of a recess.

Preferably there is provided a perforated insert member mounted in the recess between the two recess insert members at a position therein so as to define a channel between the side walls, inwardly of the base and outwardly of the perforated insert member within which the fluidizing liquid from the liquid entry opening can flow within the recess, the perforated insert member having an inwardly facing surface which spans the space between the side walls at the perforated insert member so as to confine the materials within the volume of the recess defined by the side walls and inwardly of the inwardly facing surface of the perforated insert member, the perforated insert member having an array of fluid injection holes defined therethrough which allow the injection of jets of fluidizing liquid from the channel through the perforated insert member into the volume.

Preferably the recess insert member is shaped to define an upper side wall of one recess and a lower wall of a next adjacent recess with a slurry engaging surface of a rib therebetween.

Preferably the slurry engaging surface is shaped with at least one angularly extending recess thereon for contacting and changing slurry flow over the surface.

Preferably the recess insert member includes a layer of a material attached thereto at the surface which is of increased wear resistance relative to a main material from which the recess insert member is formed. In some cases however and in some designs a material may be available which can provide both the wear resistance and the flexibility so that the extrusion may be formed in one piece.

Preferably the layer is attached by adhesive.

Preferably wherein the peripheral wall of the bowl has attached thereto for the or each recess insert member a mounting member attached to the wall and extending inwardly from the wall for engaging an abutment member on the recess insert member.

Preferably the mounting member comprises an annular band carried on the peripheral wall.

Preferably the annular band defines shoulders for engaging into a channel on the recess insert member.

Preferably the liquid supply of the fluidizing liquid injection system for fluidizing the materials in the respective recess includes a channel defined between an exterior of the at least one recess insert member and an interior of the peripheral wall.

The side walls of the recesses are preferably v-shaped so as to converge toward one another. However this is not essential and many different shapes of the side walls of the recess can be provided. Thus the side walls and particularly the upper side wall may be curved or grooved with angular grooves to provide different effects on material tending to migrate from the recess over the upper wall. it will be appreciated that the fact that the recess is formed in a piece which is extruded longitudinally allows the cross sectional shape of the recess to be tailored to whatever shape is desired. This extrusion method provides much more flexibility of shape relative to the conventional one piece molding method which limits the shaping of the bowl and its recesses to shapes which can be pulled off the male mold.

The basic shape of the outer bowl wall, if a supporting bowl wall is used, is often frusto-conical as is conventional in this art. However the arrangements used herein allow different shapes of bowl wall to be used in view of the flexibility of the extrusion insert members used to define the recesses and the absence of the conventional one piece molding system. Thus the bowl wall may be wholly or partly cylindrical and may include partly conical and partly cylindrical sections with the conical sections being either inwardly converging or outwardly diverging. The bowl wall may also be curved in cross section.

In a second embodiment described in more detail hereinafter, which is used with a bowl already having molded recesses, the insert portion has a portion which inserts into the recess and a face portion including a side portion located radially inwardly of a rib on a respective side of the recess and at least partly covering the rib so as to prevent the slurry from contacting the rib and causing wear to the rib. However the face portion may be shaped so that it reduces the contact of the slurry on the rib without actually covering the rib, particularly if it projects into the bowl to a height above the rib.

Preferably the surface of the face portion extends across the recess and onto the side portion.

Preferably the surface is shaped to define at least one surface recess radially inwardly of the respective recess. However the surface can be readily tailored to particular requirements of a bowl since the surface can be inexpensively replaced. Thus the surface may have many different arrangements and characteristics which can be selected by one skilled in the art.

Preferably the face portion includes two side portions each on a respective side of the face portion and each arranged to cover a respective one of the ribs on alternate sides of the recess. However the face portion may cover or partly cover the rib on only one side. Alternatively insert members which do not cover either rib may be formed for use where two adjacent recesses have insert members so that only one of the insert members needs to and can cover the adjacent ribs.

Preferably the side portion has an edge at an axial end thereof and an edge surface extending from the edge to the next adjacent recess and wherein the edge surface is substantially contiguous with the side wall of the next adjacent recess. Thus the side portion covers the whole of the rib and an end face of the rib. However the side portion may not in some examples cover the whole of the rib provided the side portion is shaped to reduce or prevent the impact of the slurry on the rib sufficiently to avoid wear of the rib and to concentrate the wear in the replaceable insert member.

Preferably the rib has a radially inwardly facing surface and wherein the side portion has a radially outwardly facing surface in contact with and resting against the radially inwardly facing surface of the rib.

Preferably the insert member is annular and extends around the full periphery of the recess to fill the recess to define butting ends of the insert member. However it may be made in separate angularly divided pieces. The insert member may be manufactured in a length which is sufficient to extend around the largest diameter recess and thus may be cut to length for recesses of less diameter. Alternatively the insert members may be manufactured as a set pre-formed to the required length.

Preferably the insert portion of the insert member has side walls in contact with and resting against the side walls of the recess.

Preferably there are a plurality of insert members each located in a respective one of the recesses at axially spaced locations along the peripheral wall of the bowl so as to define at least one recess between one insert member and the next which is free from an inset member to allow entry of the slurry into the free recesses. These can be set out in the pattern previously proposed in the above U.S. Pat. No. 5,586,965. However alternative patterns of filled and open recesses can be used as will be apparent to one skilled in the art.

Preferably the surfaces of the face portions of the insert members lie on a common conical surface.

According to a second aspect of the invention there is provided a replacement insert member:

for use in a centrifuge bowl for use in an apparatus for separating intermixed particulate materials of different specific gravity in a slurry where the apparatus includes:

a feed duct for feeding the slurry into the bowl so that during rotation of the bowl the intermixed particulate materials flow over a peripheral wall of the bowl for collection of heavier particulate materials on the peripheral wall and for discharge of the lighter particulate materials in the slurry from the open mouth;

a launder for collecting the lighter particulate materials in the slurry discharged from the open mouth;

a bowl;

the bowl having a base and a peripheral wall surrounding an axis passing through the base and generally upstanding from the base to an open mouth;

the bowl having a plurality of annular recesses on the peripheral wall at axially spaced positions over which the materials pass, when fed from the supply duct, so that the heavier particulate materials collect in the recesses;

each recess being defined by an upper recess side wall on the upper side and a lower recess side wall on a lower side with each of the side walls extending generally outwardly from the axis from an open mouth of the recess toward a base of the recess at the peripheral wall and converging toward one another;

the upper side wall of each recess being connected to the lower side wall of a next adjacent recess to form a rib between the recesses such that the bowl includes a plurality of recesses and a plurality of ribs arranged alternately along the side wall;

at least some of the recesses each having a fluidizing liquid injection system for fluidizing the materials in the respective recess including a liquid sup