WO1981003108A1

WO1981003108A1 - Method and apparatus for use in the killing of animals to be slaughtered

Info

Publication number: WO1981003108A1
Application number: PCT/NO1981/000011
Authority: WO
Inventors: O Braathen
Original assignee: Norges Kjott Og Fleskesentral; O Braathen
Priority date: 1980-04-28
Filing date: 1981-04-27
Publication date: 1981-11-12
Also published as: NO800143L

Abstract

Method and apparatus for killing animals to be slaughtered, by employing electric current. With the usual electrode arrangements for this purpose it has been a problem to pass the necessary stunning current through the brain (tentorium ceribelli) of the animal at the same time as the safety of the personnel and animal psychology are taken into account. The invention proposes a solution based upon the shooting-in of bolt shaped electrodes (11, 12) by means of pneumatic (20) or other force, into the head (1) of the animal to be slaughtered, whereafter the electric voltage (30) is applied and thus may flow from at least one electrode shot into a region in or adjacent the brain for the stunning thereof. The apparatus is intended to be applied primarily in slaughter houses for domestic animals such as cattle, sheep, lambs, pigs and the like.

Description

This invention relates to a method and an apparatus for use in the killing of animals to be slaughtered, where the stunning of the animal is effected by means of electric current through at least one electrode placed on the head of the animal

In slaughter houses the killing takes place with a combina¬ tion of stunning and subsequent debleeding. The stunning may be effected by shooting with a ball or a bolt shaped element, or possibly with electric current or a manual blow. Also a hydraulically operated blow element has been used in order to obtain unconsciousness before debleeding.

For the stunning' of animals in slaughter houses there is today usually employed an electric voltage which is applied to the animals by means of two electrodes placed either behind the ears, between ear and eyes, or possibly on the upper side and on the underside of the head. While the animal is uncons¬ cious debleeding is carried out.

An example of known techniques employing one electrode for applying the electric voltage, is found in US Patent 1,553,135. The patent specification shows a comparatively long, insulated, rod shaped electrode the outer end of which is manually placed against the head of the animal from above for the purpose of effecting the stunning.

It has appeared to be a serious problem to obtain a suffi¬ ciently good stunning of animals when using electric current. This is due to the fact that it is difficult to pass a suffi¬ cient current amperage through the brain of the animal, as the easiest current path is often along the skin between the electrodes. Thus, it is an uncontrollable current which flows through the brain and thereby contributes to the desired un¬ consciousness. Actually only a few millia peres of current are needed through the brain (tentorium cerebelli) in order to obtain a safe stunning.

The present invention is directed to a method of electri¬ cally killing animals to be slaughtered, characterized thereby that the electrode or the electrodes by mechanic, hydraulic, pneumatic, electromagnetic or explosive force are shot into the head of the animal to the region in which the brain is situated, that the electric current is applied at least during a portion of the time interval during which the electrode or electrodes have their projected position, and that the elec- trode or electrodes are automatically retracted when the electric current has been applied for .a sufficiently long time to give safe stunning of the animal. ■

The invention also comprise.s an apparatus for use in the killing of animals to be slaughtered, where the stunning of the animal is effected by means of electric current, comprisin at least one electrode adapted to be placed on t he head of the animal and connected to an electric voltage source. V7hat is novel and specific to the apparatus according to the invention primarily consist in means for shooting at least one electrod into the head of the animal, means for applying electric curre from the voltage source to the electrode or electrodes, contro means for controlling the shooting means in such a manner that it effects retraction of the electrode or electrodes from the projected position when the electric current has been applied a sufficiently long time to give safe stunning of the animal .

In practice there will be used either one or two electrode VJhen one electrode is used, the floor on which the animal stan or a metal member adapted to contact the animal somewhere else, for example on the back, may constitute the second electrode o counter-electrode. When two electrodes are employed, these are adapted to be connected each to one terminal cf the electric voltage source. As commonly used hitherto the vol¬ tage source may be based upon alternating 'current of conven¬ tional mains .frequency, but preferably of a lower voltage, most preferably below 48 volt.

The voltage is applied to the electrodes only during a short time interval which may be controlled, and according to one embodiment of the invention the voltage is applied only as long as the electrodes are in their projected position, i.e. shot into the head of the animal. The safety of the slaughter¬ house personnel is an important consideration in this connec¬ tion, _and as mentioned, the safety conditions are influenced both by the voltage employed and by the manner in which the electrodes may possibly be accessible to random touching when they are in their outer position. Timing of the voltage application is an advantage in many respects, and it is pre¬ ferred that the voltage is applied for only about 2 seconds as a maximum. With the common kinds of animals unconsciousness will be obtained already after approximately -₅ second, and a maximum limit of 2 seconds therefore is ample time as far as th stunning effect is concerned.

In view of the fact. that the electrodes, for example in the form of metal bolts which penetrate or are shot into the head^' to the region adjacent the brain, are supplied with a voltage in this position, the stunning is made very effective because the problem of "stray currents" outside the brain itself is eliminated. This represents a substantial difference and an improved_.effect .compared to the previously known apparatuses for electric killing. When the electrode bolts are shot com¬ pletely into the brain mass and current is applied thereto in this position, the brain tissue is paralysed 'immediately and the animal loses its consciousness at the very moment when the bolts are shot in and the current is turned on. It is not necessary, however, that the electrode bolts are shot into the brain itself, since the immediately surrounding tissue has such a character that the current will be conducted easily through the brain when the eledtrodes penetrate to this region immediately adjacent the brain. Such a limitation of the depth of penetration is of particular interest in the case of animals the brain of which shall be utilized as food for people.

This invention has the additional advantage that electric killing based on this principle to a high degree satisfies considerations having to do with the prevention of cruelty to animals and associated rules in the various countries all over the world. Moreover, both the operator of the apparatus and other personnel in the slaughterhouse will be well safe¬ guarded against electric shock by the precautions prescribed here. Time control of the apparatus and in particular of the application of the electric voltage is of significance at this point. This does not exclude the possibility that the elec¬ trodes under certain circumstances, inter alia when using a comparatively low voltage within the preferred range from about 20 volts to about 48 volts, may have the voltage applied continuously. In such case it is desirable that the electrodes are protected against random contacting when they are in the retracted position or rest position. animal for stunning electrically, may comprise only one electrode, since the counter-electrode may be the whole floor on which the animal stands. When employing a single electrode this may possibly be bifurcated, i.e. with one electrode mem¬ ber for each brain half. The bifurcated electrode bolt will then penetrate into the region adjacent the brain at two places and is connected to one terminal of a transformer or other voltage source. The other terminal of the transformer is connected to ground, i.e. the floor on which the animal stands. Preferably, the floor is then covered with water containing a salt . (for example sodium chloride) , so that the contact will be good through all the legs of the animal which are immerged into the solution.

The apparatus with the actual means for shooting the electrode bolt or bolts may possibly be mounted in an automati stunning machine or trap. In such an arrangement the actual shooting means or the stunning equipment synchroniously follows the animal in a moving conveying trap in order to effect the stunning. .

In the following description the invention shall be ex¬ plained more closely with reference to the drawing, in which Figure 1 somewhat simplified and schematically shows an apparatus according to the invention based upon a pneumatic control and shooting of electrode bolts by. means of compressed air. The compressed air components and the^* circuits shown are of conventional design per se, as will be apparent to an expert in the field of pneumatics. Figures 2 and 3 show in principle another embodiment of the invention.

In Figure 1 of the drawings there is indicated at 1 the upper part of the head of an animal to be slaughtered. A shooting device 10 having two electrodes 11 and 12 is shown in a position immediately above the head 1 just before being brought into engagement therewith.

In"-the arrangement shown here with two electrodes these are moved in parallel and are adapted to penetrate into the head 1 from the same side. This is effected by means of compressed air as the electrode bolts 11 and 12 are each moved by a separate piston 6 and 9, respectively, which may recipro¬ cate in corresponding cylinders. Since this pisto and cylinj , shall be explained more closely only with reference to the left-hand electrode 11 in the drawing.

In the rest position in which the electrode bolt 11 is shown, this is kept retracted by means of the compressed air applied to the cylinder volume 5 underneath the piston, i.e. with the air pressure acting against the piston area 6a on the underside thereof. On the upper side of the piston there i a compressed air chamber 4 which is common to both cylinders^' and pistons. The chamber 4 has an end piece 24 which permits the pressure in. chamber 4 to act against a reduced piston^' area 6b on the upper side of piston 6. Outside the end piece 24 there is provided a spring 26 which does not have any func¬ tion in connection with the forces acting on the. piston, but serves to convey electric current. In the rest position shown in which chamber 4 is subjected to atmospheric pressure as will appear from the position of valve 3, the pressure in the cylinder volume 5 beneath piston 6 will keep piston 6 in engagement with end piece 24 as mentioned above.

The actual pneumatic control circuits are shown in conven¬ tional manner with standard symbols and conduit connections drawn in the usual way. The control arrangement comprises a first signal valve 2a, a second signal valve 2b, said valve 3 and _ return valve 7 as well as a signal interrupter valve

The first signal valve 2a serves as a safety measure against release of the shooting device when the same has not been brought into engagement with an object, i.e. preferably the head of an animal to be slaughtered. For this purpose there is provided a sensor in the form of an engagement plate 13 which is able to perform a certain movement in the same direction as the electrodes 11 and 12 so that it may actuate an operating element 2ac for valve 2a. This valve is thereby shifted so that compressed air from source 20 may reach the second signal valve 2b. Valve 2b on the other hand* has a manual operating element in the form of a push button 2bc or the like, which on actuation causes shifting of this valve and puts an air conduit 15 from valve 2a in connection with an air conduit 16. which leads to signal interrupter 8. This signal interrupter is a component known per se, which after a predetermined time interrupts the flow of air therethrough. Output conduit 17 from the signal interrupter serves to shift valve 3.

Valve 3 is more or less the main component for controllin the shooting device 10, as in its rest position valve 3 puts chamber 4 in connection with the atmosphere and the cylinder volumes underneath pistons 6 and 9 in connection with the compressed air source, so that electrode bolts 11 and 12 are maintained retracted* in the rest position as mentioned above.

When valve *3 is shifted, the pressure relationships are reversed since chamber 4 will be put under pressure from sour 20 and the cylinder volumes underneath the pistons will be connected to the atmosphere through a common air conduit 14.

With the ratio indicated between piston areas 6a and 6b the reversing of the pressure relationships will have as a consequence that piston 6 acts as a so-called impact piston. This means that when the ratio between the pressure above the piston and below the piston exceeds the ration between the piston areas on the underside and the upper side, respectively of the piston, this will start to move. As soon as piston 6 has left its seat on end piece 24 the complete piston area on the upper side will become effective, and the pressure in chamber 4 will push the piston and electrode bolt 11 downwards with a J_^a-ge^{^}force. In practice said piston areas 6a and 6b —m-ay^' -or example have a ratio of 9:1. That is, when the air pressure underneath piston 6 has become lower than 1/9 of the pressure in chamber 4, the piston will start to move. This of course also applies to piston 9 in the other cylinder.

This impact cylinder principle which has been utilized here results therein that the pistons instantaneously act with a maximum force and move the electrode bolts at high velocity into the head of the animal to be slaughtered.

As soon as piston 6 has started to move, the air pressure in chamber 4 acts en return valve 7 through a conduit 18. This takes place with a certain time delay because of a throttled leakage aperture 28 of a type known per se, in con¬ duit 18. After a predetermined time return valve 7 will be

OMPI An alternating voltage of mains frequency within the voltage range of 20-48 volts as discussed above, is not the only form of electric voltage or current which may be employed. An interesting possibility exists in the employment of a pulse shaped voltage, the pulse frequency of which may be much higher than the common mains frequency, i.e. 50 Hz. In the case of a pulse shaped voltage at an increased pulse frequency it may be practical to adapt this frequency in relation to the nerve pulse frequency for the actual kinds of animals to be slaughtered.

The shape of the •electrode bolts may also be varied. In Figure 1 there is illustrated a somewhat pointed shape of the outer end of the electrodes, but also other shapes may be thought of, inter alia a hollow or tube-like shape of which the circular pheriphery may more or less constitute a sharp edge which can have a punching or cutting action in the head of the animal.

When employing two parallel electrodes as illustrated, the apparatus may be oriented transversally as shown in Figure 1, or it may be placed on the head of the animal with the electrodes oriented along a longitudinal axis. In such case the electrodes may penetrate into the forehead and the rear of the head of the animal, respectively. It is clear that the electrodes do not necessarily have to be directed in parallel as shown in Figure 1, but may be arranged at an angle with respect to each other, and possibly the electrodes may be arranged so as to be directed oppositely, for the purpose of being shot in laterally from each side of the head of the animal.

In all the different electrode arrangements or orientations which may be thought of it may be an advantage to arrange the apparatus or at least the shooting device itself on a collar or yoke adapted to suit the various kinds of animals and the points of attack desired. Such a collar arrangement may further and advantageously utilize pneumatic, hydraulic or another force, in order to press the shooting device against the head of the animal at the locations desired. Such clamping will to a significant degree be able to secure shooting-in in the possible way against the brain (tentoriuπn 7 shifted and will put air pressure from source 20 on a conduit 19 which leads to valve 3 and reset the same to its initial position, i.e. the position shown in the drawing. In this position retraction of the electrode bolts is effected since chamber 4 again is connected to the atmosphere and compressed air from source 20 is fed to the underside of the pistons through conduit 14.

In the embodiment shown here electrodes 11 ^'and 12 are sup¬ plied with a voltage permanently from a voltage source 30 with electrical wires 31 and 32 to the respective cylinders. As shown more closely at the left-hand cylinder in Figure 1, there is provided a feed-through element 33 through the cylinder wall and on the inside thereof a wire connection 35 to the spring 26. Thus, the spring acts as an electrical conductor and passes the voltage on to piston 6 which is made of an electrically conductive material and therefrom the current is passed to the electrode 11. It is obvious that surrounding parts and components must be insulated or be made of an insu¬ lating material so that short-circuiting of the current cannot take place. Thus, for example 'the end wall of each cylinder, which is provided with a guide hole for the electrodes, may be made of an electrically insulating material.

The apparatus may easily be modified in such a way that the voltage from source 30 is only applied to electrodes 11 and 12 when these are in their projected position^'. These bolt electrode or the underside of the corresponding pistons may for example be provided with an electrical contact fixed by soldering. This contact may be adapted to co-operate with a contact lo¬ cated in the lower portion of the cylinder and connected to the voltage source. Thus, when the electrode bolts are shot out under the action of compressed air as described above, the contact will be closed and the voltage will be applied to the electrode. Besides, as a further possibility, the electrical circuits may comprise for example electronic components which serve as^' a time relay and only allows the voltage to be applied during a predetermined time interval while the electrodes are projected. The necessary electrical circuits and components for such a function represent quite conventional techniques to an expert in the field of electronics. is obtained. In particular when it is important that the electrode or electrodes only penetrate almost into, but not quite into the brain of the animal, it may be an advantage to use such clamping and a collar arrangement or the like^' having guide or engagement parts adapted to suit the head shape of the animal.

Figures 2 and 3 show such a collar-like clamping device based upon pneumatic operation and having two laterally directed electrodes 41, 42.

In Figure 2 there is indicated the head 40 of a pig with an eye 40a and an ear 40b. The device- has a handle 48 with a trigger 49 and a combined conduit 58 for supplying compressed air and current from the voltage source (not shown) . Handle 48 is fixed to a central tubular frame 50 to the outer end of which are fixed cylinders 43 and 44 for moving the electrodes

41 and 42, respectively. In Figure 3 cylinder 44 is in part broken away. A yoke or collar formed by a tube 47 serves to supply compressed air to chamber 46 and a corresponding chamber in cylinder 44. The operation of cylinders 43 and 44 may be quite analogous to what is explained in connection with the air cylinders in Figure 1.

Clamping is obtained by means of arms 52, 5 being articu¬ lated to the outer end of a lateral member 51 fixed to the central frame 50. Between the upper ends of arms 52, 53 there is provided for an outwardly pushing force by means of an air cylinder 55. When this cylinder is supplied with com¬ pressed air, the outer ends of arms 52, 53 with engagement surfaces or pads 52a and 53a, respectively, will be moved towards each other so as to clamp the pig 40 behind the ears 40b as shown in Figure 2. In this position -the electrodes 41,

42 are brought to point directly into the head of the pig

40 at an inclination and laterally from each side of the head so as to aim directly at the brain of the pig.

As in the embodiment of Figure 1, Figure 2 shows a se¬ curity ϊock element 59 which is adapted to sense the engagement of the complete device against the head of the pig , whereaf er stunning may take place. The whole operation may be automatic so that when the device has been brought into the right posi¬ tion and trigger 49 is actuated, clamping arms 52,

first be moved to give a firm grip behind the ears of the p and then the shot is automatically released so as to bring electrodes 41 and 42 to penetrate into the head 40 of the p

Finally, it is obvious that compressed air operation an pneumatic control as described here in connection with the embodiments of the drawings, may be replaced by other kinds driving means and controls, since both hydraulic as purely mechanic, electromagnetic or even explosive force may be em¬ ployed for projecting or shooting-in the electrode bolts ^" an alternative to the pneumatic control there may apparentl be used electronic circuits for example, in order to carry o the necessary functions in the control means.

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_ ^*2

Claims

CLAIMS :

1. Method for use in the killing of animals to be slaughtered, in which stunning of the animal is effected by means of electric current through at least one electrode placed on the head of the animal, characterized in that the electrode or electrodes are shot with mechanic, hydraulic, pneumatic, electromagnetic or explosive force into the head of the animal to the region in which the brain is located, that the electric current is applied at least during a portion of the time interval during which the electrode or electrodes are in the projected posi¬ tion and that the electrode or electrodes are automatically retracted when the electric current has been applied for a sufficiently long time to give a secure stunning of the animal.

2. Apparatus for use in the killing of animals to be slaughtered where stunning of the animal is effected by means of electric current, comprising at least one electrode adapted to be placed on the head of the animal and connected to an electric voltage source, characterized by means (10) for shooting at least one electrode (11, 12) into the head (1) of the animal, means (31, 32, 33, 35) for applying electric current from the voltage source (30) on the electrode or electrodes (11, 12) , control means (2a, 2b, 3, 7, 8) for controlling said shooting means (10) so that the same acts to retract the electrode or electrodes from their projected position when the electric current has been applied for a sufficiently long time to give secure stunning of the animal .

3. Apparatus according to claim 2, characterized therein that it has two electrodes (11, 12) adapted to have applied thereto voltage of opposite polarities.

4. Apparatus according to claim 3, characterized in that both ele^'ctrodes (11, 12) are adapted to be moved in parallel in the same direction.

5. Apparatus according to claim 3, characterized in that the two electrodes (41, 42) are adapted to be moved in opposite directions towards each other and laterally into the head of the animal.

6. Apparatus according to any one of the preceding claims, characterized in that each electrode (11, 12, 41, 42) has a bolt or rod shape, preferably with a pointed outer end, and adapted to be projected by displacement in the longitudinal direction thereof.

7. Apparatus according to any one of the preceding claims, characterized in that the electrode or electrodes (11, 12, 41, 42) are adapted to penetrate almost into, but not quite into the brain of the animal .

8. Apparatus according to any one of the preceding claims, characterized in that said shooting means (10) is driven by compressed air.

9. Apparatus according to any one of the preceding claims, characterized by a sensing element (13) adapted to release a security lock associated with said control means (2a, 2b, 3, 7, 8) upon engagement with the head (1) of the animal.

10. Apparatus according to any one of the preceding claims, characterized therein that it is provided with a clamping device (50) to be fixed on the- head of the animal.

11. Apparatus according to any one of the preceding claims, characterized therein that the electric voltage source (30) is adapted to be controlled ^'in response to the electrode shooting so that the stunning current only flows during a time interval of preferably at least -₅ second, and not more than 2 seconds, while the electrode or electrodes are in th projected position.

12. Apparatus according to any one of the preceding claims, characterized in that the electric voltage source (30) is permanently connected to the electrode or electrodes (11, 12 and that these are protected against random touching in the retracted position.

13. Apparatus according to any one of the preceding claims, characterized in that the voltage employed is within the ran from 20 - 48 volts.

14. Apparatus according to any one of the preceding claims, characterized therein that the voltage source is adapted to supply a pulse shaped voltage, preferably having a pulse fre quency being substantially higher than the common mains frequency.