GB2253797A

GB2253797A - Endless belt guiding

Info

Publication number: GB2253797A
Application number: GB9105611A
Authority: GB
Inventors: Edwyn Graham Stobbart; Sean Kennedy
Original assignee: S C S BIOTECHNOLOGY Ltd
Current assignee: S C S BIOTECHNOLOGY Ltd
Priority date: 1991-03-16
Filing date: 1991-03-16
Publication date: 1992-09-23
Also published as: GB9105611D0

Abstract

An endless belt 17 is entrained round rollers 13 to 16, of which roller 16 is located below the plane of the others and bears downwards to tension the belt. The ends of roller 16 rotate in a rectangular frame (Fig. 3) which is supported at its other end by a universal coupling 45, which allows roller 16 to pivot about one vertical and two horizontal axes. Heavy roller 16 acts as a gyroscope, and if belt 17 drifts sideways the roller automatically tilts and restores it to centre. As shown belt 17 is of plastics mesh for dewatering farm slurry, which is gravity filtered and then squeezed between rollers 18, 19. Roller 19 and rotary cleaning brush 31 are driven by a common motor 24. <IMAGE>

Description

An Endless Belt Guide This invention relates to a guide for an endless belt assembly in which an endless belt passes around a series of rollers. In particular the invention relates to an endless belt guide fitted to liquid/solid separators in which an endless mesh belt passes around rollers, the solid matter being retained on the belt and the liquid passing through the belt.

Liquid solid separators of the above type are used for the treatment of slurry in particular animal waste slurries from intensive agricultural units.

A known apparatus for the separation of solids from a slurry is disclosed in British Patent 1437336. A problem with this apparatus is that the mesh belt can drift off centre relative to the rollers. If this happens the belt life can be reduced considerably.

It is known to compensate for this problem by having electronic sensors which sense the position of the belt, and when the belt goes off centre the sensors activate an actuator which moves a head having at least one of the belt rollers theron to counteract the drift of the belt.

Such a system is shown in Australian Patent 501491 and improves the working life of the belt However, such an electronic installation and control apparatus is expensive and complicates what is essentially a simple apparatus.

The present applicants have devised an effectively simple means of correcting for endless belt misalignment on an endless belt/roller assembly fitted to a liquid/solid separator.

Accordingly there is provided an endless belt passing around and in contact with a series of rollers, including a giude roller located out of the plane of the other rollers, wherein the guide roller rotates about an axle which is moveable in any direction relative to the belt to resist any off-centre movements of the contacting belt.

Preferably the guide roller axle has complete freedom of movement around one horizontal axis and limited freedom of movement about the other two axes.

Also accoring to the invention there is provided a method of controlling an off-centre drift of an endless belt passing around and in contact with a series of rollers including a guide roller in contact with the inside of the belt, said method including mounting the guide roller so that its axis of rotation is free to move relative to the axes of rotation of the other rollers, thereby allowing the said roller to tilt downwardly with a drifting belt, the tilting roller causing the belt to move up the inclined guide roller surface and cause the guide roller and belt to right themselves.

The invention will be described by way of example and with reference to the accompanying drawings in which: Fig 1 is a section through a liquid/solid separator according to this invention.

Fig 2 is a section through the universal joint used for control of the guide roller.

Fig 3 is a plan-view of the guide roller sub-frame.

Now with reference to Figs 1 to 3, the separator is a liquid solid separator and in particular is a separator for the separation of solids from slurries of animal waste.

The separator has a body 10 comprising a top cover 11 and base 12. The base 12 forming part of a main frame on which are mounted a series of rollers 13,14,15 and 16 around which an endless mesh belt 17 continuously passes in a clockwise direction (as seen in Fig 1). The rollers are arranged so that there is a substantially horizontal array of rollers 13, 14 and 15 with a lower roller 16 located underneath out of the plane of the other rollers.

The mesh belt is a polypropylene gauze of an appropriate size to retain the solids to be separated. Other materials such as polyethylene, polyethyleneterapthallate or nylon mesh are equally suitable.

The slurry is delivered to the separator by a feed pipe 21 or alternatively by a chute (not shown) so that it is deposited onto the mesh belt 17. The solid is retained on the belt and the liquid falls through the belt onto an inclined collecting surface 22 formed on the base 12 from which it is removed by a drain 23.

The solids on the belt are carried by the belt towards a pair of clamping rollers 18 and 19 mounted to the base 12 and which are located one roller 19 below the belt and one roller 18 above the belt. The bottom roller 19 is the main drive roller for the belt and is driven by an electric motor 24 to cause the belt 17 to pass around all the rollers 13, 14., 15, 16, and 19. The top roller 18 is mounted in a bracket 25 and a spring loaded by an adjustable spring loading device 26 towards the bottom roller 19. The two rollers 18 and 19 are interconnected via gears for simultaneous rotation.

As the belt carries the solids through the clamping rollers 18 and 19 the deposited solids are squeezed and the remaining liquid passes through the mesh onto the collecting surface 22 and the copmresed substantially liquid free solid is removed from the end of the horizontal run of belt.

The belt then passes downwards and around the lower roller 16 which is a heavy roller and is free to move relative to the body 10 so its downward load 'L' tensions the belt 17. After passing around the lower roller 16 the endless belt passes up to the first roller 13 of the horizontal run.

A brush 31 is fixed to the underside of the collecting surface 22 of the body 10 by a strut 32 and is rotated by a belt 32 connected to the drive roller 19, alternatively the brush can be driven by an independant motor. The brush 31 removes any solid matter adhering to the belt at this point.

The lower roller 16 is free to float relative to the main frame or body 10 and is of a sufficient weight to tension the belt 17 as previously discussed.

The roller 16 is a guide roller and serves to prevent the belt 17 from drifting off centre as it rotates around the rollers. The guide roller 16 is located in a sub-frame 40 (see Fig 3) so that the axle 41 of the guide roller has its ends fixed to the sub-frame 40, with the sub-frame 40 being pivotted to the main frame 10. The sub-frame 40 is a rectangular frame having side arms 42 connected by cross members 43 and 44 with the guide roller 16 located at one end of the side arms 42 and the other end of the side arms connected by the cross member 43 The cross member 43 is of a round cross section providing a pivot pin for the sub-frame 40.

The pivot pin 43 passes through a ball joint 45 which allows the sub frame to pivot with three degrees of freedom.

The ball joint 45 is connected to the main frame 10 by a strut 46 and is adjustably mounted on the strut by screw threads 47 to allow for setting up the guide roller 16 relative to the belt 17.

The ball joint 45 comprises a spherical ball 48 of PTFE, nylon, acetal resin or other suitable bearing material and is located in a spherical socket 49 in the ball joint housing 50. The cross member 43 passing through a cylindrical bore 51 in the ball 48. A coaxial bush 52 could be utilised between the cross member 43 and the wall of the bore 51 but may not be necessary.

The ball joint 45 functions as a universal joint allowing complete freedom of rotation around one horizontal axis and limited freedom of rotation around the other two axes.

Other suitable type of universal joint could be used for this purpose.

When the belt is rotating around the rollers, the speed of rotation of the heavy roller 16 builds up a movement of intertia in the roller which has a gyroscopic effect on the roller.

If the belt drifts off centre the guide roller 16 will tilt with the belt and pivot around the universal joint 45. The guide roller 16 will tilt downwards to the side to which the belt is drifting creating an inclined rotating surface. A moving belt will tend to move up an inclined rotating surface and the belt will move back up the guide roller causing it to right itself.

Claims

1. An endless belt assembly comprising an endless belt passing around and in contact with a series of rollers including a guide roller located out of the plane of the other rollers , wherein the guide roller rotates about an axle which is moveable in any direction relative to the belt to resist any off-centre movements of the contacting belt.

2. An assembly as claimed in Claim 1, where the guide roller axle has complete freedom of movement around one horizontal axis, and limited freedom of movement about the other two axes.

3. An assembly as claimed in Claim 1 or Claim 2, wherein the guide roller rotates about an axle the ends of which are secured in a sub-frame, and the other rollers are mounted for rotation about their respective axes on a main frame, the sub-frame being mounted on the main frame for movement relative thereto.

4. An assembly as claimed in Claim 3, wherein the guide roller is located at one end of the sub-frame and the other end of the sub-frame pivots relative to the main frame by means of a universal joint.

5. An assembly as claimed in Claim 4, wherein the universal joint is a ball and socket joint.

6. An assembly as claimed in Claim 5 wherein the sub-frame is connected with the to the ball of said joint, and the joint body is connected to the main frame.

7. Assembly as claimed in any one of Claims 3 to 6, wherein said the sub-frame is connected to the main frame by a universal joint located at one end of a strut whose other end is attached to the main frame, the strut being of an adjustable length.

8. An assembly as claimed in any one of Claims 1 to 7 wherein the series of rollers include support rollers mounted for rotation about their respective axes on a main frame and which hold a portion of the endless belt substantially horizontal, and the guide roller is located beneath the horizontal portion of the belt.

8. A liquid/solid separator including an endless belt assembly as claimed in any one of Claims 1 to 6 and in which the belt is a mesh belt which retains solid matter allowing liquid to pass through the belt.

9. A slurry separator including a liquid/solid separator as claimed in Claim 8.

20. A slurry separator substantially as described herein and as illustrated in the accompanying drawings.

11. A method of controlling an off-centre drift of an endless belt passing around and in contact with a series of rollers, including a guide roller in contact with the inside of the belt, said method including mounting the guide-roller so that its axis of rotation is free to move relative to the axes of rotation of the other rollers, thereby allowing the said roller to tilt downwards with a drifting belt, the tilting roller causing the belt to move up the inclined guide rotating roller surface and cause the guide roller and belt to right themselves.