AU733609B2 - Particle conditioning method and apparatus - Google Patents

Description

AUSTRALIA

Patent Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: a a a a a a a a.

Names(s) of Applicant(s): DEBEX (PROPRIETARY) LIMITED Actual Inventor(s): Philip Roelof Eiserman Gerald Francis Kuhn Address for service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne, Victoria 3000, Australia Complete Specification for the invention entitled: PARTICLE CONDITIONING METHOD AND APPARATUS Our Ref: 520637 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- 2210x 2 BACKGROUND TO THE INVENTION THIS invention relates to a particle conditioning method and apparatus. In 0 one application of the invention, the method and apparatus may be used to condition particulate material by removing and separating dust from the individual particles of the material. In other applications of the invention, individual particles of a particulate mass may be conditioned in other ways.

As an example, in the mining industry the presence of dust is a constant problem. Dust which is stuck to and carried by particulate material has.the tendency to clog various items of equipment which may be used to process the particulate material during mineral recovery operations.

*o o *oo BAKRUD OTEINETO *g* the particulate material during mineral recovery operations.

SUMMARY OF THE INVENTION According to the present invention there is provided a particle conditioning apparatus including a housing, an inlet to the housing for particles which are to be conditioned by a flow of gas, an array of parallel, inclined chutes arranged in vertically spaced and laterally staggered relationship below the particle inlet with inclined, laterally extending gaps between the chutes, whereby particles introduced into the housing through the particle inlet cascade under gravity from one chute to the next in the array thereby traversing the gaps between the chutes in the array, a conditioning gas flow inlet located to one side of the array and communicating with upper ends of the gaps between the chutes, an outlet from the housing located on an opposite side of the array, suction means connected to the outlet for drawing a flow of conditioning gas laterally from the inlet to the outlet through the gaps between the chutes and hence through the particle cascade thereby to condition the particles with the conditioning gas, conditioning gas 15 flows control means in the gaps between the chutes for controlling the flow of conditioning gas through the gaps, and a particle outlet from the housing, below the array of chutes, for removing from the housing particles which have cascaded over the chutes and been conditioned by the flow of conditioning gas.

In one application of the apparatus, it can be used to remove adhering dust from the particles. In this application, the jarring motion undergone by the particles as they cascade over the chutes tends to dislodge adhering dust which is then entrained in a flow of air which is caused to flow through the from the conditioning inlets to the gas outlet.

To improve the efficiency of the dust extraction process, it is also proposed that the apparatus include elastic mountings on which the housing is mounted and means for vibrating the housing.

According to another aspect of the invention, there is provided a method of conditioning particles, the method including the steps of causing the particles to cascade under gravity over a series of inclined, laterally Li~> staggered chutes, and passing a flow of conditioning gas through the cascading particles.

4 BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a side view of a particle conditioning apparatus according to this invention; Figure 2 shows an end view of the apparatus, looking in the direction of the arrow 2 in Figure 1; and :Figure 3 shows a cross-section at the line 3-3 in Figure 2.

DESCRIPTION OF A PREFERRED EMBODIMENT The particle conditioning apparatus 10 seen in the drawings includes a housing 12 having an upper, rectangular portion 14 formed with three particle inlets 16 in vertical side walls thereof and a further inlet 17 in the horizontal top wall thereof Each of the inlets can be closed by means of a circular plate 18. Depending on the application, any or all of the particle inlets can be opened, by removing the relevant plate(s), for the purposes of S"introducing particles which are to be conditioned into the housing 12.

Inside the housing, beneath the inlets 16 and 17, is a series of inclined chutes 20 having laterally staggered inner edges. As illustrated, the lateral staggering of inner edges of the chutes results in a configuration in which the inner edge of each chute is laterally displaced, to the right in Figure 3, relative to the inner edge of the chute immediately above it. The side edges of the chutes are supported in slots in the side plates 22 of the housing 12 and each chute carries a wear resistant lining, typically of SOLIDUR (trade mark), on its upper surface. The assembly of side plates and chutes is held together by means of tie rods 21.

Inclined, generally laterally extending gaps 22 are defined between the successive chutes. A perforated screen 24 extends in each gap between the upper surface of the lower chute and the lower surface of the upper chute defining that gap. As viewed in Figure 3, the left hand end of each gap is open. The open ends of the gaps serve as conditioning air inlets. A perforated security screen 26 extends over the open ends of the gaps and S: forms an end wall of the housing 12.

1 ~The housing 12 also includes an air outlet 28 composed of a frusto-conical portion 30 and a cylindrical pipe 32. A particle outlet 34 is provided at the lower end of the housing as illustrated.

o .In use of the illustrated apparatus, particulate material which is to o conditioned, in this case by removal of adhering dust therefrom, is introduced into a selected inlet 16 or 17, or through two or more of these inlets simultaneously. The particles of the material fall onto the chutes o and thereafter cascade under gravity over the chutes, as indicated by the numeral 36. As the particles cascade over the chutes 20, they traverse the gaps 22 between the chutes. The cascading of the particles over the chutes subjects them to repeated jarring. The jarring of the particles in this way tends to break up any particle agglomerations which may be present and also to shake free any dust which initially adhered to the particles.

-6- While the particles cascade over the chutes, conditioning air is continuously passed through the housing 12, from the left to the right as viewed in Figure 3. In this case, this is achieved by means of a suction fan or pump (not shown) connected to the pipe 32. The fan or pump draws a flow of air along flow paths extending through the open ends of the gaps 22, through the gaps themselves, through the particle cascade, through the remainder of the housing 12 and finally through the air outlet 28. As the air flow passes through the cascading particles, it entrains loose dust particles and hence removes them from the housing. Thereafter the dust particles may be removed from the air flow by any suitable means.

It will be appreciated that the velocity of the air flow through the cascading particles will determine the size of dust particles which can be entrained in °the air flow. The air velocity can be varied to suit the specific requirements o.o by varying the positions of adjustable orifice plates 40 mounted in the gaps ooo.

22.

S- After conditioning, i.e. after the particles have cascaded over the chutes and the dust has been removed therefrom, the particles leave the housing under gravity through the outlet 34.

0. S In the application described above, the particles are conditioned by dust "removal. The invention is not however limited to such applications. For instance, the air flow may be heated for the purposes of conditioning initially wet particles by drying them. In such an application, the wear resistant linings of the chutes could be heat resistant in nature. In other examples, the air flow could be replaced by a flow of steam intended to condition the particles by heating and wetting them, or by any other gaseous flow intended 7 to condition the particles in a predetermined manner.

The security screen 26 prevents manual access to the interior of the housing during the conditioning process. This may be important in situations where the particles are of a valuable nature, such as in the removal of dust from diamond-bearing aggregate. The screens 24 prevent the particles from backing up into the gaps 22, thereby preventing particle hang-ups and ensuring a smooth and continuous cascading flow of particles over the chutes.

It will also be appreciated that the inclination of the chutes is carefully selected to suit the nature of the particles which are to be conditioned. For instance, with particularly "sticky" particles the chutes may be inclined more :o steeply than with more fluent particles. Also, in situations where the particles ooi are particularly sticky and prone to agglomeration, or where the dust has a o o° high level of adherence, the housing 12 may be mounted on elastic mountings and have a vibration unit attached to it to vibrate it during particle conditioning and thereby improve disagglomeration and dust •separation.

The housing and appropriate components therein may be made of a suitable grade of stainless steel to avoid corrosion.

Claims (7)

1. A particle conditioning apparatus including a housing, an inlet to the housing for particles which are to be conditioned by a flow of gas, an array of parallel, inclined chutes arranged in vertically spaced and laterally staggered relationship below the particle inlet with inclined, laterally extending gaps between the chutes, whereby particles introduced into the housing through the particle inlet cascade under gravity from one chute to the next in the array thereby traversing the gaps between the chutes in the array, a conditioning gas flow inlet located to one side of the array and communicating with upper ends of the gaps between the chutes, an outlet from the housing located on an opposite side of the array, suction means connected to the outlet for drawing a flow of conditioning gas laterally from the inlet to the outlet through the gaps between the chutes and hence through the particle cascade thereby 1 5 to condition the particles with the conditioning gas, conditioning gas flow control means in the gaps between the chutes for controlling the flow of conditioning gas through the gaps, and a particle outlet from the housing, below the array of chutes, for removing from the housing particles which have cascaded over the chutes and been conditioned by the flow of conditioning gas.

2. 2A particle conditioning apparatus according to claim 1 wherein a screen extends 25 across the conditioning air inlet.

3. A particle conditioning apparatus according to either one of claims 1 or 2 wherein a perforated screen extends in each gap between the chutes defining that gap. W:\onia\Davin\Speal5666-98.oc

4. A particle conditioning apparatus according to any one of the preceding claims wherein the conditioning gas flow control means comprises adjustable orifice plates in each gap for controlling the flow of gas through the gaps.

A particle conditioning apparatus according to any one of the preceding claims wherein the housing is mounted on elastic mountings and a vibrating means is provided to vibrate the housing.

6. 15 A particle conditioning apparatus according to any one of the preceding claims when used to remove dust from the particles.

7. S* 0 A particle conditioning apparatus substantially as herein described with reference to the accompanying drawings. DATED: 20 March 2001 PHILLIPS ORMONDE FITZPATRICK A Attorneys for: DEBEX (PROPRIETARY) LIMITED W:\tonia\Davin\Spe\54666-98.doc