GB2130547A - Packaging fodder - Google Patents

Abstract

In a process for packaging fodder, a bale of herbage (10) is compressed in a compression chamber (12) by a pair of rams (R1, R2) and then ejected from the chamber by a third ram. Before ejecting the compressed bale, the second ram (R2) is retracted slightly to accommodate limited recovery of the bale, the bale being ejected while it is recovering. The bale is ejected into a tight-fitting bag (16), the bag then being progressively heat sealed while being simultaneously evacuated through a suction pipe (26). <IMAGE>

Description

SPECIFICATION Packaging fodder Bales of hay are bulky and therefore costly to transport and store. Hay also provides a relatively low protein fodder so that in many cases it must be supplemented with more concentrated foodstuffs such as cereals and nuts.

For these reasons hay is sometimes replaced as the bulk feed for horses and cattle by bales of cut green grass. This fodder has a higher protein content than hay and, because of its greater density, is more easily handled and requires less storage space.

Aconventional pick-up baling machine driven from, and/or pulled by, a tractor produces bales having a length of about one metre. When the bales consist of cut green grass, it is possible to reduce their length even further by compression in a separate press before packaging them in bags.

One known process for preparing and packaging fodder is described in U.K. Patent 1 512804. In this process compacted blocks of partially wilted green herbage are inserted into bags of impermeable plastics material, and the bags are then hermetically sealed. A disadvantage of the process is that the compressed bale is confined in a tight-fitting bag, and pressure can therefore build up in the bag due to release of gases from the grass as it respires.

Because the grass is compressed, the amount of gas released is considerable. The end result is often puffy bags which are prone to rupture and which are difficult to handle and transport. In severe cases the top and/or bottom seal of the bag may burst, these seals being the weakest parts of the bags.

Because of this problem it has been proposed to prevent the build-up of pressure within the bag by providing each bag with a non-return valve. In practice, however, the fitting of such valves has proved troublesome.

Moreover, the aerobic internal respiration of grass within the sealed bag can also produce appreciable amounts of butyric acid and ammonia N, and a reduction in the level of fermentable carbohydrates.

The respiration consumes valuable sources of energy and thereby reduces the nutrient value of the grass. It also encourages the growth of yeast and this may well reduce the palatability of the fodder to horses and ponies.

In accordance with the present invention there is provided a process for packaging fodder, the process comprising compressing a preformed bale of cut green grass or crop, discharging the compressed bale into a bag formed of a plastics material, inserting a suction member into the bag, progressively sealing the bag while simultaneously evacuating air through the suction member, and finally withdrawing the suction member just prior to completion of the sealing operation.

The evacuation of air from the bag prior to sealing has a number of advantages. Most importantly it prevents, or at least substantially reduces, external respiration and aerobic internal respiration of the packaged grass. There is therefore no build-up of pressure within the bag after sealing, and little or no deterioration in the nutrient value of the fodder after sealing. Moreover, we have found the compressed grass is still able to ferment due to anaerobic internal respiration.

In a preferred embodiment of the invention, the bag is progressively sealed by moving the neck of the bag through a pair of heated pressure-applying members, the air being withdrawn through a vacuum pipe.

A further problem which sometimes arises in this process is that of ejecting the compressed bales from the compressor. The higher the compression ration, the greater is the force on the walls of the compression chamber due to the compressed bale trying to return to its original size, and the greater therefore is the force required to eject the bale from the chamber. Moreover, the tendency for the bale to return to its original size hinders the transfer from the compression chamber to the eject chute.

In accordance with a further aspect of the present invention there is provided a compressor for compressing a preformed bale of cut green grass, the compressor comprising pressure-applying means for compressing a first dimension of the bale in a compression chamber, means for subsequently expanding the chamber to accommodate a limited recovery of the first dimension, and means for ejecting the compressed bale during the said recovery of the first dimension.

The chamber is preferably expanded by a reverse movement of a first pressure-applying member.

Unit costs are dependent on the size of the bag.

Even a small reduction in the size of the bag can lead to significant savings. On the other hand there are practical limits on the extent to which a bale can be compressed in any one direction without resorting to the use of exceptionally powerful presses. In addition, productivity is largely dependent on the speed with which the compressor operates, and larger more powerful rams would inevitably have a slower movement.

Accordingly, a preferred feature of the invention is that the compressor comprises first pressureapplying means for compressing a first dimension of the preformed bale and second pressure-applying means for compressing a second dimension of the bale. Moreover, one of the pressure-applying means preferably includes a pressure-applying member movable between an inclined position permitting entry of the bale into a compression chamber and a substantially perpendicular position in which the bale is compressed against an opposed wall of the chamber.

The bale generally has a rectangular section and is preferably compressed across its width by a first ram and then along its length by a second ram, the second ram then being retracted to permit a slight recovery in the length of the bale while it is being ejected by a third ram operating perpendicular to the first and second rams. This reduces the force required to eject the bale and eases the transfer of the bale into an eject chute. The chute has a dimension capable of accommodating the slight recovery in the length of the bale.

By way of example only, an embodiment of the invention will now be described with reference to the accompanying drawings in which Figure 1 is a diagrammatic side view illustrating one stage in a process for packaging compressed bales of green grass; Figure 2 is a top plan view illustrating a subsequent stage in the process; and Figure 3 and 4 are top plan views diagrammatically illustrating the evacuation and sealing of the final packages.

Referring initially to Figures 1 and 2, preformed bales 10 of cut green grass fall from an inclined conveyor 11 into a compression chamber 12, the chamber having a fixed back wall 17 and a hinged front wall 14, the front wall forming the face of a first ram R1.

The ram R1 is movable about a hinge 30 from a retracted position in which the face 14 is inclined to the vertical as shown in full outline in Figure 1, to an extended position in which the face 14 is substantially vertical as shown in chain-dot outline in Figure 1.

When the bale 10 first drops into the chamber 12 it becomes wedged between the ram face 14 and the fixed rear wall 13. The ram is then actuated to compress the dimension 'd' of the bale from the value "dl" to "d2". In practice, d1 may equal 14 inches and d2 may equal 12 inches.

The use of the hinged wall 14 reduces the operating movement of the ram R1 and thereby reduces the total operating time of the compressor for each package.

An overhead ram R2 then compresses the length of the bale from "11" to "12". In practice, 11 may be 40 inches and 12 may be 14 inches. When the ram R2 reaches the end of its compression stroke, it immediately reverses until its face lies a predetermined distance above the compressed bale. This allows the bale to recover slightly so that its length increases from 12 to 13, the bale beginning to expand toward the face of the ram as soon as the pressure on the bale is relieved.

During this recovery the bale is ejected from the chamber 12 by a third ram R3 (Figure 2). The ram R3 pushes the compressed bale through an outlet port 17 in a sidewall of the chamber 12 and into an eject chute 15. Should the chute 15 contain a previously discharged bale, the preceding bale is pushed out of the chute and into a plastic bag 16 fitted over the end of the chute, the bag being progressivley extended by the incoming bale before eventually being removed from the chute.

The sequential operation of the hydraulic rams R1, R2 and R3 is controlled by a hydraulic control circuit in response to signals received from microswitches actuated by the rams. In particular, the ram R3 does not begin its eject stroke until the ram R2 has moved back to accommodate the recovery of the bale length from 12to 13. Because the bale is then constrained between only two walls rather than four walls, the force required to eject the bale is considerably reduced and there is less difficulty aligning the bale with the outlet port 17.

Following the eject stroke of ram R3, the Rams R1.

R2, R3 return to their original positions and the cycle is repeated.

The rams are preferably hydraulic rams but the immediate retraction of the ram R2 at the end of its compression stroke is preferably achieved pneumatically.

Referring to Figures 3 and 4, the bag 16 removed from the eject chute 15 fits tightly around the compressed bale but with its top projecting about 12 inches beyond the bale. A suction pipe 26 is then inserted into this top portion 24 of the bag and the portion 24 is manually drawn over the top face of the bale and around the pipe 26 by pinching the sides of the bag together until only a small gap 28 remains between them. The evacuation of air through pipe 26 assists the pinching process. The bag is then adv arced from left to right (as viewed in Figure 3) between a pair of heated pressure-applying members 25 until the position of Figure 4 is reached. The vacuum pipe 26 continues to evacuate air from the bag while the heat seal 27 is being formed across the top of the bag during the sideways movement of the bag between members 25. When the position of Figure 4 is reached, the pipe 26 is withdrawn and the seal 27 completed by continuing movement of the bag between the members 25.

Claims (16)

1. A process for packaging fodder, the process comprising compressing a preformed bale of cut green grass or crop, discharging the compressed bale into a bag formed of a plastics material, inserting a suction member into the bag, progressively sealing the bag while simultaneously evacuating air through the suction member, and finally withdrawing the suction member just prior to completion of the sealing operation.

2. A process according to Claim 1 in which the bag is progressively sealed by moving the neck of the bag through a pair of heated pressure-applying members.

3. A process according to Claim 1 or Claim 2 in which first and second dimensions of the preformed bale are compressed before discharging the bale into the bag.

4. A process according to any one of the preceding claims in which limited recovery of the compressed bale is accommodated before discharging the bale into the bag.

5. A compressor for compressing a preformed bale of herbage, the compressor comprising pressure-applying means for compressing the preformed bale in a compression chamber, means for subsequently expanding the chamber to accommodate limited recovery of the compressed bale, and means responsive to the expansion of the chamber for ejecting the bale during its recovery.

6. A compressor according to Claim 5 in which the pressure-applying means comprises a first pressure-applying member for compressing a first dimension of the bale and a second pressureapplying member for compressing a second dimemsion ofthe bale.

7. A compressor according to Claim 6 in which the chamber is expanded by a reverse movement of one of the pressure-applying members.

8. A compressor according to Claim 7 in which the pressure-applying members comprise hydraulic rams but in which the said reverse movement of the one member is pneumatically controlled.

9. A compressor according to Claim 6 in which the first pressure-applying member comprises a wall of the compression chamber, the wall being movable from an inclined position permitting entry of the bale into the chamber and a substantially perpendicular position in which the bale is compressed against an opposing wall of the chamber.

10. A compressor according to Claim 9 in which the second pressure-applying member reciprocates in a direction parallel to the said opposed walls of the chamber.

11. A compressor according to Claim 10, in which the bale is ejected in a direction parallel to the said opposed walls but perpendicular to the move mentofthe second pressure-applying members.

12. A compressor for compressing a preformed bale of herbage, the compressor comprising a first pressure-applying member for compressing a first dimension of the bale in a compression chamber, a second pressure-applying member for compressing a second dimension of the bale while the bale is retained by the first pressure-applying member in the compression chamber, and a third pressureapplying member movable in a direction perpendicular to both the first and second pressure-applying members for ejecting the compressed bale from the chamber.

13. A compressor according to Claim 12 in which the first pressure-applying member forms a wall of the chamber and is movable from an inclined position permitting entry of the bale into the chamber and a substantially perpendicular position in which the bale is compressed against an opposed wall of the chamber.

14. A vacuum-sealed pack of cut green grass or crop when packaged by a process according to any one of the Claims 1 to 4.

15. A process for packaging fodder, the process being substantially as herein described with reference to the accompanying drawings.

16. A compressor for compressing bales of herbage, the compressor being substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings.