APPARATUS FOR PASSING AN ELECTRICAL CURRENT THROUGH POULTRY AND THE LIKE

Abstract: An apparatus (10) for passing an electrical current through a series of birds (32) for the purpose of killing the birds or of stunning the birds prior to slaughter comprises a continuous shackle train (12) in which the shackles (16) are adapted to move the birds along a predetermined path. A water bath (38) is located below a section of said path so that the heads of the birds will pass through the water bath as they traverse said path section. A plurality of electrical contacts (30) is adapted to engage and move with those shackles which are traversing said path section at any given moment and electrical circuitry (not shown) having a connection with the water bath and with the electrical contacts acts to apply the desired electrical current to the birds as they traverse said path section.

Description: Apparatus for Passing an Electrical Current Through Poultry and the Like The present invention relates to an apparatus for passing an electrical current through poultry and the like e.g. rabbits, with the purpose of stunning or killing them. According to the present invention. an apparatus for passing an electrical current through poultry and the like (hereinafter referred to as poultry etc.) for the purpose of killing them or stunning them prior to slaughter comprises a continuous shackle train in which the shackles are adapted to move the poultry etc. along a predetermined path, a water bath located below a section of said path so that the heads of poultry etc. will pass through the water bath as they traverse said path section, a plurality of electrical contacts separate from but adapted to engage and move with those shackles which, at any given moment, are traversing said path section, and electrical circuitry having a connection with the water bath and with said electrical contacts thereby to apply said electrical current to the poultry etc. as they traverse said path section. It is to be understood that throughout the present specification, the term "shackle" includes both the part which fetters the animals and the section by which this part is suspended from the shackle train drive line. Conveniently, the contacts above referred to displace the pivoted shackles away from the vertical whereby the horizontal component ofthe combined weight ofthe poultry etc. and the relevant shackle is effective to increase the engagement force between the electrical contacts and the shackles. In one such embodiment, for example, the path section above referred to requires the shackle line to move over a part of a circle and the electrical contacts are themselves mounted to move along a circular path which is coaxial with but ofa greater radius than the path followed by the pivoted upper ends ofthe shackles. Conveniently in this last case, the shackle train includes insulating carriages from which the shackles are pivotally suspended, the shackle train is constrained to move along said part-circular path by an indexing rotor which engages said carriages, and the electrical contacts are carried on a larger diameter contact rotor mounted coaxially beneath and rotating at the same angular speed as the indexing rotor. Conveniently, the water bath is ofa part-annular shape which is "co-axial" with the indexing and contact rotors i.e. the centre line of the bath lies on a circle which is co-axial with the two rotors. Alternatively, however, the bath could be of rectangular or any other suitable plan shape. Conveniently, the front end ofthe water bath (whether annular or not), is preceded by an upwardly-sloping array of two or more horizontally-disposed insulating rollers so that the heads ofthe shackled poultry etc. are raised before leaving the roller array for entry into the water bath. Conveniently, one or more horizontally-disposed insulating rollers are provided at the rear end ofthe bath to assist the withdrawal ofthe poultry's heads therefrom. In preferred embodiments, the apparatus is designed to fit in a 180° bend in the shackle line. The diameter of this bend is determined by the maximum required duration of stun and the maximum required line speed. The stunner consists of two concentric wheels mounted horizontally below the bend in the line. The upper wheel is ofthe same diameter as the bend and is fitted with plastic teeth at a spacing that coincides with the conveyor trolleys. This provides a synchronised drive to the stunner. The lower wheel has a slightly larger diameter than the top wheel. Both wheels are rigidly fixed together at a separation not greater than the length of the shackle drop leg. The lower wheel is fitted with electrical contacts that coincide with the positions ofthe dog teeth on the upper wheel and hence with the shackles. Electrical supply to these contacts is through a multiple ring commutator or other convenient means. There may be individual supplies for each animal in the bath (preferably plus two extra). However, this can be achieved via multiple connections to the same supply around the circumference ofthe wheel, although, with a constant current stunning regime, no two should make contact at the same time, for example they may be located at diametrically opposite points of the rotor with the tank occupying something less than a semi-circle. The lower wheel has a slightly larger diameter in order to increase the force between the shackle drop leg and the electrical contact on the wheel. The water bath is positioned under the wheels and conveniently is a part annular bath which follows the circumference ofthe bend. However, the bath could instead be square in plan and ofa size able to accommodate the same stunning action as the part-annular bath. A linear system is also envisaged with the teeth and contacts synchronised on a belt or track. An embodiment ofthe invention will now be described, by way of example only, with reference to the accompanying partly schematic drawings, in which:- Figure 1 shows a side view of one embodiment of stun/kill apparatus in accordance with the present invention for use with poultry and using a vertical-axis rotor system for stunning the birds; Figure 2 shows an inverted plan view of part ofthe same apparatus; Figures 3 and 4 show part elevational and plan views of the water bath with its roller arrays; Figures 5 and 6 show simplified side and plan views of an alternative embodiment ofthe invention using an inclined-axis rotor system for stunning the birds; Figures 7 shows a simplified side view of another alternative embodiment using a two-level shackle-support system to provide part-immersion and stunning; and Figure 8 shows a simplified largely diagrammatic side view of a further alternative embodiment in which individual water baths are lifted up for part-immersion and stunning. Thus referring first to Figure 1 ofthe drawings, an apparatus 10 in accordance with the present invention includes a continuous shackle train 12 comprising a series of insulating carriages 14 from which the shackles 16 are pivotally suspended by means of bolts 18. the pivotal nature of the connection arising from the fact that the bolt is of a significantly smaller diameter than that ofthe shackle aperture through which it passes. Figure 1 shows that section ofthe shackle line in which the shackles are constrained to move along a part-circular path by the action of an indexing rotor disc 20, insulating teeth 22 of which engage carriages 14 as shown. Secured below the indexing rotor disc by a central support column 24 and six hollow connection conduits 26 is a larger diameter contact rotor disc 28. This is made of insulating plastics material, such as polyethylene and carries at its periphery twenty four electrical contacts 30 of basically the same tooth-like configurations as the twenty four indexing teeth 22 carried by disc 20 (see Figure 2). Typical diameters of rotor discs 20, 28 are 1 15 cms and 120 cms, respectively. As will be clear from Figure 1, the larger diameter of the contact rotor disc 28 results in the contacts 30 displacing the shackles 16 away from the vertical so that a component ofthe combined weight (W) ofthe shackles 16 and the shackled birds 32 (only one of which is shown in the drawing) will enhance the contact pressure between the contacts and the shackles thereby to improve the electrical connection therebetween. For a displacement of angle θ from the vertical, this pressure-enhancing component will be W sinθ. To prevent the shackles swinging out too far. an insulating restraint chain 34 is provided to interconnect adjacent shackles as shown. The lower end ofthe column 24 rests on the floor 36 ofthe processing house where it is in part surrounded by a roughly semi-circular water bath 38 mounted on a lipped table 40. An alternating or direct current supply is fed to the contacts 30 through a junction box 42, a slip-ring (or commutator) assembly 44, and insulated cables 46 leading from assembly 44 via conduits 26 to the individual contacts 30. Where a commutator is used for item 44, this is arranged so that the contacts 30 are only live during and just before (and possibly also just after) immersion ofthe bird's head in the water bath 38. Where a slip-ring assembly is used instead, this conveniently comprises twelve slip rings each of which provides a permanent connection with a respective pair of diametrically opposed contacts 30 so that in this case all the contacts 30 are live all the time. Electrical connection to the water bath 38 is made by means of an electrode 48 having a supply line 50,51 connected to either end ofthe electrode. The bath assembly is completed by an upwardly sloping array of horizontal insulating rollers 53 (Figures 3 and 4) arranged at the inlet end of the water bath and a single outlet roller 55 provided at the outlet end ofthe bath. Advantages of using roller array 53 instead of a continuous ramp, say, are first that frictional effects are reduced, causing the bird less stress, and secondly that the discontinuous surface provided by the rollers lessens the risk of current being applied prematurely to the shackled birds because of splash-back from the bath 38. The remaining items appearing in the drawings comprise carriage rollers 57, the support rail 59 on which these run, and, bolted to an I-beam 61 ofthe processing house, a support bracket 63 which registers the upper end of column 24. As an optional safety feature, the rail 59 may be flanged as shown at 65 to shield the carriage/rail system from access by operatives. The operation of the apparatus will be clear form the preceding description. To summarise, the birds 32 are loaded into the shackles at a location not shown in the drawings, and the shackle train moves the loaded shackles into engagement with the rotors elements 22 and 30 as shown in Figure 1. As the shackle train 12 moves around the support column 24 it rotates the indexing rotor disc 20 and at the same time the contact rotor disc 28. This results in the birds being conveyed, head downwards, over the ramp provided by roller assembly 53 to bridge the gap between the shackles 16 and the water bath 38 and thereby to complete the stunning (or killing) circuit for the birds. The required electric current is supplied via junction box 42 and slip ring or commutator assembly 44. Exit ofthe birds from the bath is facilitated by roller 55 as already described. In modifications (not shown) of the illustrated embodiment, the indexing and/or contact rotors take the form of belts or tracks with the teeth 22 and the contacts 30 arranged to move along exactly the same paths over the water bath 38 as in the illustrated double disc rotor embodiment. In an alternative embodiment using belts or tracks, the teeth and contacts engage with the shackles over a linear section ofthe shackle line path rather than over a 180° bend. However, as with the illustrated embodiment, the contacts are so disposed as to displace the shackles from the vertical so as to increase the force between shackle and contact with a view to enhancing the electrical connection therebetween. Turning now to Figures 5 and 6, these figures show part of an alternative embodiment in which the common rotor axis is inclined at about 15 ° to the vertical to promote immersion of the birds' heads in the water bath without the need for the roller- ramp 53 used in the previous (vertical-axis) embodiment. It will be seen that the contacts 30 are profiled to allow relative movement between the shackles and the contacts along the relevant section ofthe path. Figure 7 shows how part-immersion can be effected using an appropriately bent support rail 59 to provide a two-level shackle-support system for part immersion and stunning ofthe birds in the water bath 38. The operation of the later embodiments (Figures 5-7) is exactly analogous to that ofthe earlier-described embodiments mutatis mutandis, and the same reference numerals have been used throughout to indicate like items.. Figures 8 shows a simplified side-view of a rather different design of apparatus in which the birds remain at the same level during stunning and individual water baths rise up to provide the desired part-immersion and stunning over the relevant section ofthe shackle path. Although a linear shackle-line system is illustrated in which the electrical contacts 30 are provided on a belt 70 and the individual water baths 38 are raised and lowered by a plurality of rams 72 mounted in a carousel system, the apparatus could equally well be adapted for use with the part-circular stunning path used in the previously described embodiments. In place of rams 72, cams (not shown) could be used instead to raise and lower the baths 38. Although the apparatus ofthe present invention can be used with a constant voltage system, it is preferred that the electrical circuitry operate to provide each bird with the same amount of electric current substantially independently of the electrical resistance of the bird concerned. A first such system is described in BTG's patent GB 2275169. A second such system, especially suited for use with the apparatus of the present invention, is described in Silsoe Research Institute's co-pending patent application of the same date as the present application and entitled Current Controller. In practice, the current delivered by the electric circuitry and the time for which this current is applied to the poultry or other animals are predetermined by staff operating the apparatus to imply with any animal welfare regulations in force at the time. In the embodiments described above, the stunning (or killing) times may be set by an appropriate choice ofthe bath length and the shackle-train speed. Switching the electric power supply to the stunning circuit on and off can be actuated by sensors of any convenient type, viz: mechanical, electrical, optical, imaging, proximity, position etc. e.g. (a) electrically, by sensing current flow; (b) mechanically, by a switch and appropriately positioned activator; and (c) optically, by detecting the presence of a bird etc and turning on the supply. In each case, an appropriate electronic circuit may be used to time the duration ofthe stun and turn it off.

Claims: Claims 1. An apparatus for passing an electrical current through poultry and the like for the purpose of killing them or stunning them prior to slaughter comprises a continuous shackle train in which the shackles are adapted to move the poultry etc. along a predetermined path, a water bath located below a section of said path so that the heads ofthe poultry etc. will pass through the water bath as they traverse said path section, a plurality of electrical contacts separate from but adapted to engage and move with those shackles which, at any given moment, are traversing said path section, and electrical circuitry having a connection with the water bath and with said electrical contacts thereby to apply said electrical current to the poultry etc. as they traverse said path section. 2. An apparatus as claimed in Claim 1 in which the contacts displace the pivoted shackles away from the vertical whereby the horizontal component ofthe combined weight of the poultry etc. and the relevant shackle is effective to increase the engagement force between the electrical contacts and the shackles. 3. An apparatus as claimed in Claim 2 in which the path section requires the shackle line to move over a part of a circle and the electrical contacts are themselves mounted to move along a circular path which is coaxial with but of a greater radius than the path followed by the pivoted upper ends ofthe shackles. 4. An apparatus as claimed in Claim 3 in which the shackle train includes insulating carriages from which the shackles are pivotally suspended, the shackle train is constrained to move along said part-circular path by an indexing rotor which engages said carriages, and the electrical contacts are carried on a larger diameter contact rotor mounted coaxially beneath and rotating at the same angular speed as the indexing rotor. 5. An apparatus as claimed in Claim 4 in which the water bath is of a part-annular shape which is co-axial with the indexing and contact rotors. 6. An apparatus as claimed in Claim 4 or Claim 5 in which the front end ofthe water bath is preceded by an upwardly-sloping array of two or more horizontally-disposed insulating rollers so that the heads ofthe shackled poultry etc. are raised before leaving the roller array for entry into the water bath. 7. An apparatus as claimed in Claim 6 in which one or more horizontally-disposed insulating rollers are provided at the rear end of the bath to assist the withdrawal of the poultry's heads therefrom. 8. An apparatus as claimed in Claim 4 or Claim 5 in which the common rotor axis is outwardly inclined to the vertical and the electrical contacts are profiled to allow an amount of circumferential slip between the contacts and the shackles whilst the shackles move over said part-circular path. 9. An apparatus as claimed in Claim 8 in which the common rotor axis is inclined at an angle of between 10° and 30° to the vertical. 10. An apparatus as claimed in Claim 10 in which the angle of inclination is at or about 15° to the vertical. 1 1. An apparatus as claimed in Claim 4 or Claim 5 in which the rail or other support means supporting the shackles as they move along said part-circular path is at a sufficiently lower level than the remainder of the rail to result in the heads of the poultry etc being immersed in the water bath as the shackles move along said part-circular path. 12. An apparatus as claimed in any preceding claim in which the water bath comprises a plurality of individual water-containing vessels, the apparatus including lifting means operative to lift the vessels to a height at which the heads of the poultry etc will pass through the water bath as the shackles move along said section ofthe predetermined path. 13. An apparatus substantially as hereinbefore described and/or as illustrated in the accompanying drawings.

Inventors: KETTLEWELL PETER JOHN, MEEHAN ANDREW MARK, RICHARDS JOHN GORDON, SPARREY JULIAN MARK, KETTLEWELL, PETER, JOHN, MEEHAN, ANDREW, MARK, RICHARDS, JOHN, GORDON, SPARREY, JULIAN, MARK
Applicants: BRITISH TECH GROUP, KETTLEWELL PETER JOHN, MEEHAN ANDREW MARK, RICHARDS JOHN GORDON, SPARREY JULIAN MARK, BRITISH TECHNOLOGY GROUP LIMITED, KETTLEWELL, PETER, JOHN, MEEHAN, ANDREW, MARK, RICHARDS, JOHN, GORDON, SPARREY, JULIAN, MARK
Application year: 1996
Main classification: A22B3
IPC codes: A22C21