AU2006201151A1 - Tungsten particle delivery system - Google Patents

Description

AUSTRALIA

Patents Act 1990 H B BELL; JP BELL COMPLETE SPECIFICATION STANDARD PATENT Invention Title.

Tungsten particle delivery system The following statement is a full description of this invention including the best method of performing it known to us:- Tungsten Particle Delivery System Introduction to the Invention This invention relates to the dispensing of tungsten and other particulate material of similar flow characteristics and in particular, to a device allowing a high level of delivery control to a range of particles.

Background of the Invention The controlled distribution of particulate materials, including particulate materials having rough, abrasive surface characteristics that give rise to cohesion and aggregation, pose particular problems where the smooth delivery of such particles is difficult to achieve due to the poor flow characteristics of the particulate material.

Tungsten particles are one example of such a particulate material, exhibiting such flow characteristics which result from the very sharp and irregular micro-surface morphology of the particles, which do not encourage ready flow between adjacent particles and tend to cause aggregation and clumping of particulate materials whenever a steady and controlled flow of tungsten particles is desirable or required. Particulate powder flow is critical to many industrial processes. It effects repeatability and uniformity of the particulate delivery. Tungsten particles are particularly affected by their highly faceted surface morphology and density which can often result in highly impeded flow characteristics for this material.

Whilst modifications to tungsten particulate materials have been investigated in the art and been shown to provide improved particulate morphology and improved flow-rate characteristics, such treatments and modified particulate materials are expensive and not always readily available. In contrast, the free availability of raw tungsten particulate material is guaranteed and highly cost-effective. The ability to improve the handling of such material would greatly enhance the economic use of tungsten particulate material and greatly improve the industrial application of this product.

One object of the invention is to provide an improved particle handling and delivery method and device.

Statement of the Invention In a first aspect the invention provides a particulate delivery device including a vertically orientated storage hopper for storing said particles, said hopper including an inlet for receiving said particles and an outlet for dispensing said particles wherein the m:\specifications\500000\504000\504257capmaw.doc outlet incorporates a rotatable roller positioned proximate to said outlet for intercepting said particles wherein the rotation of said feed roller draws said particles from said hopper for dispensation at a rate determined by the speed of rotation of said roller.

The feed roller may be positioned underneath the outlet at a suitable distance to intercept and disrupt the aggregate of particles protruding from the outlet so as to effect the controlled flow of particles from the hopper. The feed roller is most preferably positioned transversely across the outlet of the hopper.

The outlet may include a feed collar for directing the particles to the roller. The feed collar may include a terminal skirt with the skirt including a primary aperture adapted for contiguous cooperation with the roller and one or more secondary apertures adapted for alignment to cooperate with a direction of rotation of the roller so as to assist in the drawing of particles from the hopper.

The secondary apertures may be provided in a variety of sizes so as to allow the user a choice in delivery rate from the hopper. The speed of rotation of the roller can be varied to further control the rate of dispensing the particles.

The delivery device may also include a distribution means positioned under the roller so as to collect the dispersed particles for subsequent distribution to the required worksite at the preferred rate of delivery.

The proximity of the feed roller to the feed collar is such that the restricted flow characteristics of particles prevent particles stored in the hopper from traversing the gap between the feed roller and the feed collar except under the influence of the rotation of the feed collar, which serves to draw the particulate matter accumulated from the hopper in the immediate vicinity of the feed collar across the surface of the rotating feed roller and from there into the distribution funnel for regular and controlled distribution for the required site.

The feed collar may include a primary aperture for delivering the particulate materials to the surface of the drive roller and may also include a secondary aperture formed at the periphery of the collar, most preferably on a skirt adapted to traverse the distance between the feed collar and the feed roller and ensure a snug and contiguous engagement with the feed roller.

The particles are most preferably tungsten.

Detailed Description of the Invention The invention will now be described with reference to Figures 1 to 5 and the accompanying Legend.

Figure 1 shows a schematic front view of the device of the invention.

m:\specifications\500000\504000\504257capmaw.doc Figure 2 shows a schematic side view of the device of the invention.

Figure 3 shows a schematic front view of the invention within a protective case.

Figure 4 shows details of the feed rollers.

Figure 5 shows a side view of the feed collar, skirt and feed roller along with details of the skirt apertures.

Legend 1. Hopper 2. Inlet 3. Outlet 4. Feed Collar Feed Roller 6. Distribution Funnel 7. Drive Motor 8. Primary Aperture 9. Secondary Aperture Skirt 11. Roller Face 12. Dimples Fluting 13. Particle Diversion Funnel 14. Feed Tube Dispensing Nozzle 16. Welder 17. Feed Speed Control Referring firstly to Figures 1 and 2, the internal workings and mechanics of the device of the invention are shown with the invention comprising a tungsten or similar particulate delivery device having a storage hopper 1 acting as a reservoir to hold the particulate material ready for delivery. The hopper includes a general purpose inlet 2 at a top end thereof for receiving bulk particulate materials and an outlet 3 at a second end thereof with the hopper positioned in a generally vertical orientation for gravity fed delivery of the particulate material. At the outlet end the hopper constricts into a general funnel shape in the form of a particle diversion funnel 13. The diversion funnel serves to minimise any tendency for the particulate material to immediately fall into the outlet region 3, which has a tendency to cause the material to clog or bind together as a m:\specifications\500000\504000\504257capmaw.doc result of the inherent highly faceted nature of the particulate material which inhibits and restricts the ability of the material to freely flow. The particle diversion funnel 13 assists the delivery of material into the hopper in a manner to disperse the material as it falls toward the confined apertures associated with the outlet 3. This action limits the packing of the particulate material and assists delivery. The outlet 3 of the hopper includes a feed collar 4 adapted to direct the particulate material leaving the hopper.

The feed collar is most preferably provided with a skirt 10 as detailed in Figure 5 so as to ensure snug and contiguous cooperation with the feed roller 5 positioned thereunder.

The feed roller 5 is a generally cylindrical roller embossed with an appropriate roller face 11 which can be made up of dimples, transverse knurling or chevron shaped knurling, depending on the size and nature of the particulate material to be delivered.

The intrinsic nature of the particulate material is such that its limited ability to flow is determined by virtue of its surface morphology such that it will come to rest on the feed roller and proceed no further. The feed collar skirt 10 is provided with a primary aperture 8 allowing the bulk of the particulate material to flow down onto and into contact with the surface of the feed roller 5. The skirt is also provided with secondary apertures 9 at the side thereof, which are differentially dimensioned so as to provide for the delivery of a selection of particulate sizes and types.

In order to draw material from the hopper, the feed roller is rotated such that the cooperation between the particulate material resting within the confines of the feed collar and skirt in contiguous contact with the feed roller but within the confines of the skirt region 10, is caused to be drawn from within the confines of the skirt, through the secondary aperture 9 by cooperation with the roller face 11. For example, if the particulate material in question is of generally spherical shape, the roller face 11 of the feed roller will be provided with a series of dimples, sized and configured to cooperate with the spherical particle size so as to draw spherical particles from the confines of the skirt through the secondary aperture 9 for delivery. Alternatively, if an irregular and fine particulate material is to be delivered, an alternative feed roller can be used having transverse scoring across the roller face or chevron-shaped scoring in order to correctly control and draw the delivery of this type of particulate material from a device. The skirt is rotatable so as to expose the appropriate side aperture to the rotating direction of the roller.

A distribution funnel 6 is provided underneath the general area of the feed roller for receiving the delivery of particulate material and with reference to Figure 3, the distribution funnel can be seen to feed the delivered particulate material to a dispensing nozzle 15. In this manner, the regular and controlled delivery of the tungsten or other m:\specifications\500000\504000\504257capmaw.doc particulate material can be readily controlled for delivery to the site required, which in this case, will be to cooperate with a welder 16 so as to provide tungsten particles within the weld-pool delivered by the welder. This allows for the application of tungsten coating to surface harden metallic products.

The rate of delivery of particulate material is controlled by a feed speed control system 17. The speed control electronically controls the operation of a drive motor 7 thereby causing the feed roller to rotate at a controlled and appropriate speed.

In a particularly preferred embodiment, the control of the device of the invention can be linked to a welder such that a refined and precise control of the delivery of tungsten particulate materials can be ensured such that the most appropriate quantity and type of particulate material is delivered to the weld-pool. Such delivery systems and switching can include provisions for alternate delay of the welder or the particulate delivery, where for example, in the case where heavy gauge material is being treated with tungsten coating, the welder can begin and as soon as a weld-pool has commenced, the subsequent delivery of tungsten particulate particles can begin and be incorporated in the progressing weld-pool. Alternatively, the switching can be arranged for tungsten coating of light gauge metallic products where the tungsten particles will begin to flow prior to the activation of the welder such that the weld-pool will occur over the top of the tungsten particulate material coating the light gauge metallic product to be coated, thereby providing a measure of protection and preventing the welding from blowing holes through the light gauge metallic material.

The invention provides for the first time, a device and method for a highly controlled delivery of raw particulate material of various grades, where particulate material, including tungsten particulate material, does not require any steps of refining or improvement of the intrinsically poor flow characteristics such that the device of the invention allows the economic use of this readily available material in a highly controlled manner ensuring repeatability, regularity and highly efficient application of tungsten particulate materials to a variety of industrial situations including tungsten coating where the device of the invention is used in cooperation with a welding system.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

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Claims (9)

1. A particulate delivery device including a vertically orientated storage hopper for storing said particles, said hopper including an inlet for receiving said particles and an outlet for dispensing said particles wherein the outlet incorporates a rotatable roller positioned proximate to said outlet for intercepting said particles wherein the rotation of said feed roller draws said particles from said hopper for dispensation at a rate determined by the speed of rotation of said roller.

2. The device of claim 1, wherein said feed roller is positioned underneath said outlet at a distance to intercept and disrupt the aggregate of particles protruding from said outlet so as to effect the controlled flow of said particles from said hopper.

3. A device according to claim 1 or 2, wherein said feed roller is positioned transversely across the outlet of said hopper.

4. A device according to any one of claims 1 to 3, wherein said outlet includes a feed collar for directing said particles to said roller.

5. A device according to claim 4, wherein said feed collar includes a terminal skirt wherein said skirt includes a primary aperture adapted for contiguous cooperation with said roller and one or more secondary apertures adapted for alignment to cooperate with the direction of rotation of said roller to assist in the drawing of particles from said hopper.

6. A device according to claim 5, wherein the said secondary apertures vary in size to allow the user a choice in delivery from said hopper.

7. A device according to any one of claims 1 to 6, wherein the speed of rotation of said roller can be varied to control the rate of dispersing of said particles.

8. A device according to any one of claims 1 to 7, including a distribution means positioned under said roller to collect said dispersed particles for distribution to the required worksite at the preferred rate of delivery. m:\specifications\500000\504000\504257capmaw.doc

9. A device according to any one of claims 1 to 8, substantially as hereinbefore described with reference to the figures. Dated this 17th day of March 2006 H B Bell; JP Bell Patent Attorneys for the Applicant: F B RICE CO m:\specifications\500000\504000\504257capmaw.doc