Drill sample particle distributor

Abstract

A particle distributor assembly 10 for distributing the particles of a drill sample is described. The distributor assembly comprises a stationary inlet tube 14 through which particles enter the distributor assembly 10, and a rotatable distributor head 16. The rotatable distributor head 16 has an upwardly directed inlet 18 offset from a central axis of rotation of the distributor head 16 and a transversely directed outlet 22 wherein, in use, when the distributor head 16 is rotated at high speed particles entering the distributor head inlet are accelerated outwardly in a radial direction through the distributor head outlet. The particle distributor assembly 10 also has a distributor nozzle 24 having an inlet 26 and an outlet 28, the nozzle inlet 26 being aligned with the stationary inlet tube and the nozzle outlet 28 being aligned with the distributor head inlet. The distributor nozzle 24 is supported between the inlet tube 14 and the distributor head 16 in such a manner that it is constrained from rotating while the nozzle outlet 28 is able to oscillate in a circular motion with the distributor head inlet 18. In use, the oscillating motion of the nozzle outlet 28 helps to promote particle flow and produce a more representative distribution of particles exiting from the distributor head outlet 22.

Claims

1. A particle distributor assembly for distributing the particles of a drill sample, the distributor assembly comprising: a stationary inlet tube through which particles enter the distributor assembly; a rotatable distributor head having an upwardly directed inlet offset from a central axis of rotation of the distributor head and a transversely directed outlet wherein, in use, when the distributor head is rotated at high speed particles entering the distributor head inlet are accelerated outwardly in a radial direction through the distributor head outlet; and, a distributor nozzle having an inlet and an outlet, the nozzle inlet being aligned with the stationary inlet tube and the nozzle outlet being aligned with the distributor head inlet, the distributor nozzle being supported between the inlet tube and the distributor head in such a manner that it is constrained from rotating whilst the nozzle outlet is forced to oscillate in a circular pattern by the rotation of the distributor head inlet whereby, in use, the oscillating motion of the nozzle outlet helps to promote particle flow and produce a more representative distribution of particles exiting from the distributor head outlet.

2. A particle distributor assembly as defined in claim 1, wherein the distributor nozzle is supported between the inlet tube and the distributor head by a flexible support member.

3. A particle distributor assembly as defined in claim 2, wherein the flexible support member is in the form of an annular plate of flexible, resilient material.

4. A particle distributor assembly as defined in claim 3, wherein an outer circumference of the plate is mounted on a housing of the distributor assembly and an inner circumference of the plate is fixed to the nozzle inlet.

5. A particle distributor assembly as defined in claim 4, wherein the inner circumference of the plate is fixed to the nozzle inlet by a retaining ring.

6. A particle distributor assembly as defined in claim 2, wherein the flexible support member and distributor nozzle are manufactured as a single integrated component.

7. A particle distributor assembly as defined in claim 1, wherein the distributor assembly further comprises an annular skirt surrounding the rotatable distributor head and adapted to redirect the particles exiting from the distributor head outlet in a downwards direction.

8. A particle distributor assembly as defined in claim 7, wherein the skirt is provided by a cylindrical housing wall of the distributor assembly.

9. A particle distributor assembly as defined in claim 1, wherein the rotatable distributor head is driven by a drive motor.

10. A particle distributor assembly as defined in claim 9, wherein the drive motor comprises a hydraulic motor.

11. A particle distributor assembly as defined in claim 1, wherein the distributor head and the oscillating distributor nozzle are balanced and rotation speeds of between 50 to 500 rpm are achievable with near perfect sample distribution from the distributor head outlet and with no material hang-up.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The nature of the invention will be better understood from the following detailed description of a specific embodiment of the drill sample distributor, given by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 is top perspective, partially cut-away view of a first embodiment a drill sample particle distributor according to the invention;

(3) FIG. 2 is a top perspective, partially cut-away view of the drill sample particle distributor, similar to FIG. 1 except that the top material feed cone has been removed for clarity;

(4) FIG. 3 is a section view of the drill sample particle distributor through the lie A-A as shown in FIG. 2; and,

(5) FIG. 4 is an enlarged top perspective, partially cut-away view of the drill sample particle distributor similar to that of FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) A preferred embodiment of a particle distributor assembly 10 for distributing the particles of a drill sample at the inlet of a cone splitter 12, as illustrated in FIGS. 1 to 4, comprises a stationary inlet tube 14 through which drill sample particles enter the distributor assembly 10. A rotatable distributor head 16 is provided, having an upwardly directed inlet 18 offset from a central axis of rotation 20 (see FIG. 3) of the distributor head 16. A transversely directed outlet 22 is in direct fluid communication with the distributor head inlet 18 wherein, in use, when the distributor head 16 is rotated at high speed particles entering the distributor head inlet 18 are accelerated outwardly in a radial direction through the distributor head outlet 22.

(7) The sample particle distributor assembly 10 further comprise a distributor nozzle 24 having an inlet 26 and an outlet 28. The nozzle inlet 26 is aligned with the stationary inlet tube 14 and the nozzle outlet 28 is aligned with the distributor head inlet 18, the distributor nozzle 24 being supported between the inlet tube 14 and the distributor head 16 in such a manner that it is constrained from rotating. At the same time the nozzle outlet 28 is able to oscillate in a circular motion with the distributor head inlet 18 whereby, in use, the oscillating motion of the nozzle outlet 28 helps to promote particle flow and produce a more representative distribution of sample particles exiting from the distributor head outlet 22.

(8) Preferably the distributor assembly 10 further comprises a stationary annular skirt 30 surrounding the rotatable distributor head and adapted to redirect the sample particles exiting from the distributor head outlet in a downwards direction.

(9) In view of the problems with the prior art noted above, it was realised that to provide a more representative distribution of sample particles over a cone splitter with inconsistent feed material flows, a much greater rotational speed of the distributor or cone is required. However, as noted above, high rotational speeds of cutters or cones through a sample stream lead to delimitation error and also balance and safety issues due to rotating mass.

(10) It was recognised that by spreading the sample radially against an inner wall of the skirt 30 it would be possible to rotate the distributor head 16 at high speed while using the skirt 30 to redirect the sample particles downwards to fall over a stationary cone 32 of the cone splitter 12 in the traditional manner. The sample particles then have little or no radial or rotational motion as they fall over the cone 32.

(11) Initial attempts to distribute sample particles via a rotating head with the inlet of the head concentric with the centre of rotation at speeds greater than about 50 rpm, led to major problems with material hang-up and reduced flow in the head. As the centre of rotation of the head is also the centre of the inlet tube, up to 50% of the head wall will impart a centrifugal force on any contained material away from the distributor head outlet direction. As rotational speed increases, that material then will not exit the distributor head outlet and consequently blocks the entire distributor assembly.

(12) However by locating the distributor head inlet 18 offset from the central axis of rotation of the distributor head 16 and the inlet tube 14, these problems can be substantially eliminated. The oscillating motion of the nozzle outlet 28 imparts no centrifugal forces to the sample particles whilst in the distributor nozzle 24, and in fact particles flowing through the distributor nozzle 24 experience a violent horizontal action at any point in the distributor nozzle which helps promote sample flow and virtually eliminates hang up.

(13) The sample particles flow through the nozzle outlet 28 into the inlet 18 of rotating distributor head 16, where the entire sample portion is now on one side (the outlet side) of the central axis of rotation 20 and is consequently accelerated out in a radial direction through the distributor head outlet 22 to impact the skirt 30 and subsequently fall over the cone 32. In the illustrated embodiment the skirt is provided by a cylindrical housing wall 30 of the distributor assembly 10, as can be seen most clearly in FIGS. 3 and 4. However the skirt 30 may also be manufactured or moulded as a separate item to provide better flow and/or wear characteristics.

(14) Preferably the distributor nozzle 24 is supported between the inlet tube 26 and the distributor head 16 by a flexible support member 36. In the illustrated embodiment the flexible support member is in the form of an annular plate 36 made of flexible, resilient material, for example, rubber. The distributor nozzle 24 is suspended by and restrained from rotating by the annular plate 36, as the nozzle outlet 28 is forced to oscillate in a circular pattern by the rotation of the distributor head 16. In use, the plate 36 wobbles and stretches to accommodate the oscillating motion of the distributor nozzle 24. The wobbly plate 36 of this embodiment is formed with a series of holes at spaced intervals about its circumference to further facilitate the wobbling and stretching of the rubber.

(15) An outer circumference of the wobbly plate 36 is mounted on the housing wall 30 of the distributor assembly 10, and an inner circumference of the wobbly plate 36 is fixed to the nozzle inlet 26. In this embodiment the inner circumference of the plate is fixed to the nozzle inlet by a retaining ring 40, as can be seen most clearly in FIGS. 2 and 4. In another embodiment the flexible support member 36, retaining ring 40 and distributor nozzle 24 may be manufactured as a single integrated component.

(16) Both the distributor head 16 and the oscillating distributor nozzle 24 are balanced and rotation speeds up to 500 rpm are now achievable with near perfect sample distribution over the cone 32 and with no material hang-up. In this embodiment, the rotatable distributor head 16 is driven by a hydraulic motor 42 that is fixed to the lower cone splitter assembly 44. However it will be appreciated that any suitable drive motor may be used to drive the distributor head.

(17) The sample material is fed into the distributor assembly 10 via a feed chute 46 which directs the sample particles into the inlet tube 14. A connecting flange 48 is provided between the material feed chute 46 and the distributor assembly 10. The connecting flange 48 also serves to retain the inlet tube 14, and clamps the outer circumference of the wobbly plate 36 to an annular flange on the upper edge of the housing wall 30, as can be seen in FIG. 1. In this manner the distributor assembly 10 can be fully integrated with the cone splitter 12 to form a single compact unit.

(18) On the other hand, the distributor assembly 10 may not necessarily need to feed to a cone splitter (as it does in this embodiment), but may be used to distribute sample particles directly to sample cutters or collectors. As the sample is distributed evenly against the skirt 30 and falls evenly from the skirt there may not be a need for the cone 32. This would simplify and shorten the overall length of the assembly.

(19) Now that a preferred embodiment of the drill sample particle distributor has been described in detail, it will be apparent that the embodiment provides a number of advantages, including the following: (i) It provides an effective means of providing a more representative distribution of particles of a drill sample at the inlet of a cone splitter. (ii) The non-rotating distributor nozzle distributes the sample particles without material hang-up by allowing the nozzle outlet to oscillate in a circular pattern over the cone splitter. (iii) It allows a stationary cone to be used which avoids the inherent constraints and limitations of rotary cone splitters. (iv) It is simple to operate and can be retrofitted to existing splitters.

(20) It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, the manner of supporting the distributor nozzle to prevent it from rotating whilst permitting the nozzle outlet to oscillate in a circular motion may vary considerably from that shown. The wobbly plate provides an effective way to do this; however it will be appreciated that other mechanical arrangements may also suffice. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described.