AU767862B2 - Densifier - Google Patents

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT a a *aa.

a a a a Name of Applicant: Actual Inventor Address for service is: Mineral Processors (WA) Pty Ltd Tony Frank Mason WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Invention Title: "Densifier" Details of Associated Provisional Application No(s): PQ0274 filed on 10 May 1999 The following statement is a full description of this invention, including the best method of performing it known to me:- "Densifier" This invention relates to a densifier which can be used with slurries to increase their density.

Background The densifier according to the invention is intended for use in the thickening of slurries of milled or naturally occurring ore fines and the densification of material which are used as medium solids in heavy medium densimetric separation methods.

Disclosure of the Invention Accordingly, the invention resides in a densifier comprising a chamber having a central axis and defined by a pair of opposed end walls and a side wall, an inlet opening into the side wall adjacent to one end wall and/or at the one end wall wherein the inlet axis is positioned relative to the central flow axis such as to :°oooo induce a rotating flow of slurry around the central axis, said chamber being of 15 substantially circular cross section and wherein the side wall is generally Sdivergent from the one end wall to the other end wall, a first outlet provided at or in the region of the junction of the side wall and the other end wall and a second outlet coaxial with the central axis provided in the other end wall.

According to a preferred feature of the invention the inlet is disposed to be 20 generally tangential to the side wall.

According to an alternative preferred feature to the previous preferred feature of the invention the flow path defined by the inlet has a curved configuration which is of a reducing radius as the flow approaches the side wall. According to one embodiment of the invention the flow path defined by the inlet has the general form of an involute curve.

-3- According to a preferred feature of the invention, said side walldefines a substantially cylindrical portion of the chamber, said substantially cylindrical portion disposed in the region of the inlet. According to one embodiment, said substantially cylindrical portion comprises a portion of the side wall downstream from the inlet. According to a further preferred feature of the embodiment, the remaining portion of the side wall, between said portion of the side wall downstream from the inlet and the other end wall, is divergent with resect of the central axis. According to a further preferred feature of the embodiment remaining portion of the side wall is uniformly divergent.

According to a further preferred feature of the invention, the second outlet further comprises a tubular portion which extends inwardly from the other end wall into the chamber.

According to a further preferred feature of the invention the first outlet comprises a plurality of openings at the junction of the side wall and the other end wall.

According to a further preferred feature of the invention the first outlet comprises a slot formed at the junction of the side wall and the other end wall.

According to a further preferred feature of the invention the first outlet is controlled by a valve.

The invention will be more fully understood in the light of the following description of one specific embodiment.

"Brief Description of the Drawings The description is made with reference to the accompanying drawing which is a schematic sectional illustration of a slurry densifier according to the embodiment.

-4- Description of the Specific Embodiment The embodiment provides a densifier whereby the thickening or densification of a slurry is achieved by utilisation of centrifugal forces which are generated by introduction of the slurry into the device. The slurries with which the embodiment is to be used comprises a mixture of water or any other suitable liquid and particulate solids which may be of differing density and which are to be separated from each other. As a result of the application of the embodiment the high density solids (relative to the fluid employed) are centrifuged away from the fluid in order that the stratified and thickened solids can be discharged oooo separately from the less dense contents of the slurry.

The embodiment comprises a chamber 11 having a first end wall 13 and a second end wall 15 which is separated by a side wall 17. In this regard, the chamber 11 has a substantially circular cross section. The side wall comprises a o **first cylindrical portion A in which the side walls are substantially parallel and which extends from the first end wall 13 for a portion of the distance between the end walls 13 and 15 and a second portion B which lies between the first portion A and the second end wall 15 and which is divergent to define a substantially frusto-conical surface.

The chamber is provided with an inlet 19 which opens into the first portion A of the side wall 17 adjacent the first end wall 13 and which has an orientation such that slurry being introduced into the chamber 11 is induced to rotate about the central axis of the chamber around the side wall 17. This can be achieved by positioning the inlet 19 such that it is tangential to the central axis at the point of entry into the chamber 11. As a result of the rotation of the slurry within the chamber 11, it will be caused to undergo a rotational action about the central axis of the chamber 17 and while undergoing that action will progress axially towards the second end wall The chamber 17 is provided with two outlets at the second wall 15, which comprise a first outlet 21 which is provided at the junction of the side wall 17 with the end wall 15 and a second outlet 23 which is located in the second end wall coaxial with the central axis of the chamber 17. The second outlet 23 is associated with a tubular member 25 which extends inwardly into the chamber from the second end wall 15 and serves as a "vortex finder".

As a result of the rotation of the slurry within the chamber 11, the slurry becomes stratified according to the density of the contents of the slurry whereby the more dense solids are retained closely adjacent to the side wall 17 whilst the less 10 dense fluid and any low density solids that are entrained within the slurry and *"*which have a density near to or less than the density of the fluid will occupy the central portion of the chamber 11. As a result the stratified thickened solids will pass from the first portion A of the side wall 17 to the second portion B of the side wall 17 and thence to the first outlet 21 to exit the chamber 11, whilst the 15 fluid and less dense solids will remain substantially centrally within the chamber 11 to pass axially through the chamber 11 to the second outlet 23 to exit the chamber 11.

In utilisation of the embodiment the fluid pressure of the slurry at the inlet 19 will be such as to induce a flow having sufficient angular velocity within the chamber 20 11 to create the necessary centrifugal forces to achieve the desired vortex and the resultant centrifugal classification of the contents of the slurry in its passage to the first and second outlets 21 and 23. In this regard, it is the intention of the embodiment that the turbulence created in the stratum of thickened solids along the second portion B of the side wall 17 will be insufficient at or near the outlets to cause the thickened solids to be mixed with the bulk of the fluid which is passing to the second outlet. Furthermore, it is anticipated that by utilisation of the divergent second portion B of the side wall 17 the second outlet can comprise a relatively large vortex finder 25 which will extend into the vortex formed by the tangential flow of the feed to allow a larger volume of fluid and less dense solids to be extracted from the device from the chamber without -6interfering with the stratum of densified solids located adjacent to the side wall 17.

In addition, it is anticipated that the density of the material being extracted from the first outlet 21 can be controlled by utilisation of a throttling device, or valve, or suitable gate provided in the side wall 17 adjacent to the second end wall Alternatively, the first outlet 21 can comprise a substantially continuous slot provided between the second end wall 17 and the adjacent end of the side wall 17.

i According to an alternative embodiment the inlet is configured such that the flow S 10 path defined by the inlet has a spiralling curved configuration which is of a reducing radius as the flow approaches the side wall. According to a particular example of the embodiment the curvature of the flow path has the general form of an involute curve.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

0 It should be appreciated that the scope of the invention need not be limited to the particular scope of the embodiment described above.

Claims (12)

1. A densifier comprising a chamber having a central axis and defined by a pair of opposed end walls and a side wall, an inlet opening into the side wall adjacent to one end wall and/or at the one end wall wherein the inlet axis is positioned relative to the central flow axis such as to induce a rotating flow of slurry around the central axis, said chamber being of substantially circular cross section and wherein the side wall is generally divergent from the one end wall to the other end wall, a first outlet provided at or in the region of the junction of the side wall and the other end wall and a second outlet coaxial with the central axis provided in the other end wall.

2. A densifier as claimed at claim 1 wherein the inlet is disposed to be generally tangential to the side wall.

3. A densifier as claimed at claim 2 wherein the flow path defined by the inlet 15 has a curved configuration which is of a reducing radius as the flow approaches the side wall. According to one embodiment of the invention the flow path defined by the inlet has the general form of an involute curve.

4. A densifier as claimed at any one of the preceding claims wherein said side wall defines a substantially cylindrical portion of the chamber, said substantially cylindrical portion disposed in the region of the inlet.

5. A densifier as claimed at claim 4 wherein said substantially cylindrical portion comprises a portion of the side wall downstream from the inlet.

6. A densifier as claimed at claim 4 or 5 wherein the remaining portion of the side wall, between said portion of the side wall downstream from the inlet and the other end wall, is divergent with respect to the central axis. -8-

7. A densifier as claimed at claim 4 or 5 or 6 wherein the remaining portion of the side wall is uniformly divergent.

8. A densifier as claimed at any one of the preceding claims wherein the second outlet further comprises a tubular portion which extends inwardly from the other end wall into the chamber.

9. A densifier as claimed at any one of the preceding claims wherein the first outlet comprises a plurality of openings at the junction of the side wall and the other end wall.

A densifier as claimed at any one of the preceding claims wherein the first outlet comprises a slot formed at the junction of the side wall and the other end wall.

11. A densifier as claimed at any one of the preceding claims wherein the first outlet is controlled by a valve.

12. A densifier substantially as herein described. Dated this seventh day of October 2003. Mineral Processors (WA) Pty Ltd Wray Associates Perth, Western Australia Patent Attorneys for the Applicant(s)