GB2254822A

GB2254822A - Pellet forming apparatus

Info

Publication number: GB2254822A
Application number: GB9206724A
Authority: GB
Inventors: Michael Harris
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-04-16
Filing date: 1992-03-27
Publication date: 1992-10-21
Also published as: GB9206724D0

Abstract

A method of forming pellets of material by causing the material to flow in molten condition through perforations. So that the method can be used for producing pellets of pitch and other bituminous and resinous substances, it includes the steps of feeding the molten material into a rotating dish with perforated side walls and controlling the temperature of the material and/or the speed of rotation of the dish. <IMAGE>

Description

Pellet forming apparatus The invention relates to a pellet forming apparatus in particular for the forming of pellets of pitch and other bituminous and resinous substances.

Previously employed methods of forming pellets of various substances have included the use of perforated plates through which the substance, in molten condition, has been able to flow under the force of gravity, the streams of substance flowing through the holes having been caused to break up into discrete droplets and during their fall to ground level having solidified in pellet form.

Such methods have been adequate for producing, for example, lead shot but for producing pellets of other materials such as pitch and other bituminous and resinus materials are not altogether suitable for various reasons. The object of the invention is to provide a method of and apparatus for producing pellets of such other materials.

According to one aspect of the invention, there is provided a method of making pellets of meltable material, the method including the steps of feeding molten material into a rotating dish with perforated side walls, and controlling the temperature of the material and/or the speed of rotation of the dish to determine the size of the pellets.

According to another aspect of the invention, apparatus for forming pellets of meltable material includes a rotatable dish with perforated side walls, means for feeding molten material to said dish, and means for rotating said dish. The means for rotating the rotatable dish may be constituted by an electric motor and associated speed controller. The rotatable dish may be a flat bottomed dish with an upstanding peripheral side wall and will preferably be rotatable about a vertical axis. The rotatable dish may have a substantially cylindrical side wall and depend from a vertically extending drive shaft. A feed pipe through which the molten material is fed to the rotatable dish may be provided with a heating element so that adjustments of material temperature can be made.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which:- Figure 1 is a side view of pellet forming apparatus embodying the invention, and Figure 2 is a perspective view of a rotatable dish forming part of the apparatus.

Referring now to Figure 1 of the drawings, the experimental apparatus there illustrated includes a rotatable dish 10 mounted on the lower end of a drive shaft 12 which extends vertically downwards from an electric motor 14. The motor is fitted with a speed controller (not shown) so that the rotational speed of the dish can be varied. A pipe 16 is arranged to discharge molten material into the dish at a controlled rate from a holding tank in which it can be raised to a suitable temperature. The apparatus is located some distance above ground level.

As shown in Figure 2, the rotatable dish is a flat bottomed dish with an upstanding peripheral side wall, the side wall alone being provided with closely spaced perforations 18.

The arrangement is such that when the rotatable dish has been set in motion, the molten material can be discharged into the dish at a controlled rate. It is found that the rotation of the dish causes the molten material to be thrown out by centrifugal force through the perforations in the side wall in the form of small droplets of material which form themselves into perfect spheres before falling to the ground. By the time the spheres of material reach the ground they have solidified.

It is found that by varying the speed of rotation of the dish, the pellet size can be varied. The temperature of the material as it is discharged into the dish is also important. However, it is found that a relatively high temperature can be used, this being advantageous in providing a superior grade of product. (It is proposed to provide electric heating elements in the feed pipe 16 so that adjustments of material temperature can be made both conveniently and safely).

It has been found that the apparatus described above has been ideal for the manufacture of pellets of pitch. The pellets produced have been found to be of a quality superior to that of pellets produced by previously available apparatus.

However, it is thought that the apparatus will also be useful for producing pellets of other bituminous and resinous materials.

It will of course be understood that, by using a rotatable dish the holes in the upstanding side wall of which are of a different size, different sized pellets of material can be produced. However, by varying the speed of rotation of the dish, and by carefully controlling the temperature of the molten material, the exact pellet size can be controlled.

Various modifications can of course be made and it will be understood that in a full sized commercial apparatus the apparatus illustrated in Figure 1 will be enclosed within a tank from which the pellets produced can be removed either continuously or from time to time.

The optimum size of rotatable dish, the required size of the perforations in its side wall, the optimum speed of rotation of the dish and optimum temperature of the molten material being used can of course all be determined by trial and experiment.

Claims

CLAIMS:

1. A method of making pellets of meltable material, the method including the steps of feeding molten material into a rotating dish with perforated side walls, and controlling the temperature of the material and/or the speed of rotation of the dish to determine the size of the pellets.

2. Apparatus for forming pellets of meltable material, the apparatus including a rotatable dish with perforated side walls, means for feeding molten material to said dish, and means for rotating said dish.

3. Apparatus according to claim 2, in which the means for rotating the rotatable dish are constituted by an electric motor and associated speed controller.

4. Apparatus according to either one of claims 2 and 3, in which the rotatable dish is a flat bottomed dish with an upstanding peripheral side wall.

5. Apparatus according to any one of claims 2 to 4, in which the dish is rotatable about a vertical axis.

6. Apparatus according to either one of claims 2 and 3, in which the rotatable dish has a substantially cylindrical side wall and depends from a vertically extending drive shaft.

7. Apparatus according to any one of claims 2 to 6, in which a feed pipe through which the molten material is fed to the rotatable dish is provided with a heating element so that adjustments of material temperature can be made.

8. A method of making pellets of meltable material, substantially as hereinbefore described.

9. Apparatus for forming pellets of meltable material, constructed, arranged and adapted to operate substantially as hereibefore described with reference to and as illustrated by the accompanying drawings.