GB2035822A

GB2035822A - Mixing bulk materials

Info

Publication number: GB2035822A
Application number: GB7940834A
Authority: GB
Original assignee: WALLEY C
Current assignee: WALLEY C
Priority date: 1978-12-02
Filing date: 1979-11-27
Publication date: 1980-06-25
Also published as: GB2035822B

Abstract

A mixing device for bulk materials, particularly an agricultural trailer for mixing and dispensing silage, concentrates and other animal feedstuffs, includes a non- tipping body (10) within which rotates a main agitator (12) having members (14) which travel closely along the walls (11) of a lower zone of the body to carry material therein upwardly during part of their travel, and a secondary rotating agitator (16) towards the top and to one side of the body which operatively intercepts material carried towards it by the main agitator, separates it therefrom and returns it thereto. A part (15) of the body containing the secondary agitator can be opened for discharge of material under the same action of the agitators, in the case of a feed trailer discharge being at sufficient height to clear the feed fence of a stockyard. <IMAGE>

Description

SPECIFICATION Mixing device This invention relates to devices for mixing bulk quantities of animal feedstuffs incorporating silage or other fodder and/or mixing materials of similar non-flowable dry, moists, pasty and/or fibrous content. The invention is particularly but not exclusively directed to a self-mixing agricultural feed trailer or other vehicle enabling silage or the like to be mixed with meal, concentrates and other feedstuffs as used in the intensive husbandry of highyielding dairy cattle.

Such mixing is desirable where a herd of cattle is housed or yarded together as the precise proportions of ingredients making up the feed can be regulated by the farmer according to current requirements, e.g. for most economical milk production, while giving all the animals access to a common bulk supply made up uniformly. The feed can be delivered to the animals once a day for consumption by them over a period so saving labour and encouraging better digestion, and as the expensive and tasty concentrates etc.

are distributed throughout the mixture the animals cannot pick and choose, and all receive a fair share.

It is known to provide self-mixing feed trailers but these have been complex and expensive items of machinery, in one example mixing is effected by providing three contrarotating auger agitators to circulate material from end to end of a hopper body. The nature of silage, which is wet, fibrous, and not easily cut, divided or stirred means that considerable power is necessary, the augers have to be of massive strength, and the mixing process takes a considerable time - upwards of 1 5 minutes for a full load. Moreover, discharge from known vehicles is at a low level giving rise to problems where feed is to be delivered over or through feed fences to yarded stock.

The object of the invention is to provide a mixing device, and particularly an agricultural mixing vehicle, which is cheap, reliable in use, effective and simple in operation, and in which the loading, mixing and discharging operations can be carried out particularly speedily and efficiently with a minimum of labour and no special auxilliary fixed or other equipment such as fixed storage hoppers or the like.

According to one aspect of the invention there is provided a mixing device comprising a container body, a main agitator operatively driven for circulation within the body and provided with members which travel in close proximity to at least a lower zone of the body walls to carry material along them in an upward direction during part of their travel, and a secondary rotatably driven agitator positioned towards the top and to one side of said zone to intercept material carried towards it by the main agitator in use, separate it from the main bulk of the material, and return it to said bulk.

According to another aspect of the invention there is provided a method of mixing material including the steps of providing a container for holding a bulk quantity of the material to be mixed, actuating a main agitator within said container to cause at least a part of said material lying against a lower zone of the container walls to be swept therealong in an upwardly extending path, and rotating a secondary agitator in a position which will intercept at least part of the material moving in said path to displace it therefrom and return it to the main bulk.

One way of carrying out the invention is now described in detail by way of example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view of an agricultural feed mixing trailer viewed from its front end, Figure 2 is a similar view from another angle of said trailer discharging over a feed fence, and Figure 3 is a diagrammatic lateral section of the trailer on line 3-3 of Fig. 1.

A two-wheeled tractor drawn trailer is provided with a non-tipping body 10 having an open top and a part-cylindrical lower zone defined by a curved floor 11 centred on a longitudinal axis A (Fig. 3) of the trailer and which is without any discharge opening.

On said axis A there is journalled a main agitator 1 2 having a cylindrical envelope of revolution which occupies substantially the whole of the body 10, its main shaft being provided with spoked spiders 1 3 which support four equi-angularly spaced longitudinal agitator bars 1 4. These bars travel in close proximity (about 25-30 mm clearance) along the curved wall 11 of said lower zone and are attached to the spiders 1 3 by resilient mountings so that they are spring loaded in the outwardly radial direction. This avoids damage if lumps of material should become wedged between bars 14 and wall 11.

Somewhat above the horizontal plane of axis A and to the right hand side (as viewed in the drawings) of the main envelope of body 10 is a part-cylindrical laterally projecting body extension 1 5 within which is a secondary agitator 1 6 journalled on a second longitudinal axis B (Fig. 3) and including a number of randomly arranged (i.e. non-spiraly disposed) pointed tines 1 7. Agitator 16 is driven in the same direction of rotation as main agitator 12, i.e. anti-clockwise as viewed in the drawings.

Both agitators are driven from and in the same direction of rotation as the tractor power take-off shaft by speed-reducing sprockets and roller chains, the drive being taken firstly from a primary shaft 18 to secondary agitator 1 6 by a chain drive 1 9 at the front of body 10 and secondly, with a more substantial speed reduction, from the shaft of agitator 1 6 to the main agitator shaft by a chain drive 20 at the rear of body 10 (Fig. 3), thus the drive speed of agitator 1 6 is considerably greater than that of agitator 12, and as agitator 1 6 is much smaller in diameter its peripheral speed is very much greater than the peripheral speed of agitator 1 2. For example agitator 1 6 may be driven at 10 times the speed of revolution of agitator 12, a typical operating speed of the latter being about 7 r.p.m.

The overall diameter of agitator 1 6 is such that it has substantial running clearance within extension 1 5 and projects a small distance (possibly 50-75 mm) into the main body envelope just above the upward termination of the curved wall 11 so that it is in close proximity to the path swept by the main agitator bars 1 4.

In use, the trailer is loaded with a bulk quantity of materials to be mixed, conveniently by means of a tractor front-end loader, e.g. silage, concentrates, meal, and/or other feed ingredients or additives while both agitators are kept in rotation. Mixing takes place as a continuous process while loading is carried out so that no time is wasted. The action of the main agitator 1 2 is to sweep the material around the curved wall 11 of the lower zone of body 10 and upwards towards secondary agitator 1 6. The tips of tines 1 7 of the latter intercept a peripheral portion of the mass of material as it moves upwards, shredding or tearing it away from the main bulk and carrying it rapidly around within extension 1 5 to return it onto the top of the main rotating bulk.In this way it is not necessary for the heavily loaded main agitator 1 2 (which has to move the entire load) to tear or cut through the sticky and fibrous silage. Additionally rotation of main agitator 1 2 may provide mixing by a tumbling action on the material especially if it is of a light or more open consistency e.g. due to the tearing action of the secondary agitator 16, also depending to some extent on the volume of material in body 10; this action may not be very effective with a full load in which case agitator 1 6 will play a greater part. The combined action of both agitators gives speedy and effective mixing of the entire bulk in a very short time, it has been found in practice that the load will be adequately mixed by the time the trailer has been filled.For example an 8.5 cubic metre capacity body 10 will accommodate 4 to 4.70 tonnes of silage and concentrate which will be mixed in 1 minutes or less.

Mixing can proceed while the trailer is travelling to a discharge position.

When ready for discharge a longitudinally extending top hinge door 21 forming the laterally outer side wall of extension 1 5 is opened by means of hydraulic rams at each end while the agitators are maintained in motion. The material intercepted by secondary agitator 1 6 is thrown from extension 1 5 and drops through the open door instead of being returned to bulk as referred to above. Discharge is at sufficient height (over 1.38 m, conveniently 1.45 m) to clear a normal feed fence 22 as indicated in Fig. 2, thus the trailer can be driven along the fence of a stockyard to deliver the ready-mixed bulk feed to the cattle therein in a single operation without any manual handling.

It has been found in practice that the action of the agitators during discharge will completely empty the trailer without any provision for tipping, oopenings in the main body or special discharge mechanism. As the body empties, the bars 14 of main agitator 1 2 continue to carry material upwards along curved wall 11 to deliver it to secondary agitator 1 6 until the body is swept completely clear.

The tines 1 7 or other formations of the secondary agitator 1 6 are preferably not arranged in a spiral pattern because it has been found that this tends to drive-all the material to one end of the body; it is preferred that mixing is not effected by any substantial axial transfer of material but rather by actions of rotational tumbling with removal from and return to the main bulk. Any tendency for ingredients not to be evenly distributed due to this action can be avoided by ensuring that concentrates etc. are loaded generally along the length of the trailer rather than in one position, it is found that this does not cause any great difficulty in practice.

As the two agitators are the only moving components in contact with the material and they are driven in the same direction and at one speed throughout the full operating cycle the complexities of gear boxes, reverse or speed change drives, special discharge augers and the like are avoided, the weight and complexity of the mechanism is kept to a minimum, and easy cleaning, maintenance and repair can be carried out. The drive mechanism is readily accessible on the exterior of body 10 after removing safety covers (not shown).

The height of discharge is a particular advantage in modern stock-raising methods.

The above described trailer may have other applications in agriculture or elsewhere, and the invention could be applied to a static mixing device or installation, or to other forms of vehicle, e.g. a self-propelled lorry.

Claims

1. A mixing device comprising a container body, a main agitator operatively driven for circulation within the body and provided with members which travel in close proximity to at least a lower zone of the body walls to carry material along them in an upward direction during part of their travel, and a secondary rotatably driven agitator positioned towards the top and to one side of said zone to intercept material carried towards it by the main agitator in use, separate it from the main bulk of the material, and return it to said bulk.

2. A device as in Claim 1 wherein the lower zone is part-cylindrical defined by body walls in the form of a curved floor and the main agitator is rotatable about a substantially horizontal axis in a cylindrical envelope of revolution.

3. A mixing device as in Claim 2 wherein said members of the main agitator are longitudinal agitator bars.

4. A mixing device as in Claim 3 wherein said bars are resiliently mounted so that they are spring loaded in the outwardly radial direction.

5. A mixing device as in Claim 2, 3 or 4 wherein both agitators revolve in the same direction.

6. A mixing device as in any one of the preceding claims wherein the secondary agitator is driven at a substantially higher peripheral speed than the main agitator.

7. A mixing device as in any one of the preceding claims wherein the secondary agitator includes a plurality of randomly arranged tines.

8. A mixing device as in any one of the preceding claims wherein the secondary agitator operates in an enclosure which can selectively opened to permit discharge of material from the body under the action of the agitators.

9. A mixing device as in Claim 8 in the form of a vehicle, said discharge being at a height and to one side of the direction of travel thereof.

10. A mixing device as in Claim 9 wherein said discharge height is over 1.38 m.

11. A method of mixing material including the steps of providing a container for holding a bulk quantity of the material to be mixed, actuating a main agitator within said container to cause at least a part of said material lying against a lower zone of the container walls to be swept therealong in an upwardly extending path, and rotating a secondary agitator in a position which will intercept at least part of the material moving in said path to displace it therefrom and return it to the main bulk.

1 2. A method as in Claim 11 further including the step of opening a discharge door adjacent the secondary agitator while continuing said actuation of both agitators in order to discharge material from the container.

1 3. A mixing vehicle substantially as here it before described with reference to and as shown in the accompanying drawings.