Patent Description:
In known prior stunner systems, a pulsating low DC voltage has been applied. The pulsating DC voltage, usually in the <NUM>-<NUM> volt range for chickens, <NUM>-<NUM> volts for small turkeys, and <NUM>-<NUM> volts for larger turkeys, works well for most poultry processors. However, such pulsating DC voltages are not acceptable for those localities requiring a so-called "stun-to-kill" approach.

<CIT> discloses an apparatus <NUM> for passing an electrical current through a series of birds <NUM> for killing or stunning the birds prior to slaughter comprises a continuous shackle train <NUM> in which the shackle <NUM> are adapted to move the birds along a arcuate path. A water bath <NUM> is located below a section of said path so that the heads of the birds will pass through the water bath. A plurality of electrical contacts <NUM> 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. Shackle train drive is effected by disc <NUM>.

In general, most stunners used outside North America are based upon a design developed in Western Europe. These European stunners operate as "water bath" stunners. This means that the birds' heads and necks are dragged through a tank of electrically charged water. This results in a very inconsistent stun, and, when combined with European style killing machines which cut only one side of the bird's neck, results in birds still being alive when reaching the scalder. This is the main reason that many European countries now require the "stun-to-kill" practice.

However, when a bird is killed in a stunner with electrical current, there is a very strong possibility of causing damage to the carcass, such as broken bones and hemorrhaging of blood vessels. Poultry processors have been looking for alternative stunning methods to improve the "stun-to-kill" procedure so that the birds can be stunned with less resulting product damage.

<CIT> of Simmons provided a step forward in the art. As described in that patent, a saline solution is contained in an elongated trough, which is mounted at the end portions of four non-electronically conducting posts. The trough is filled with saline solution. The trough has an ingress funnel arrangement designed to control the thrashing of to-be-electrically stunned birds and an elongated grid having a portion immersed in the solution and a downstream portion out of the solution. The four posts extend upwardly and terminate in threaded portions. A frame carriage is provided which has four corners, and at the four corners are suitably mounted driven gears with internal bores and threads adapted to engagingly rotate about the threaded portions of the ports. The carriage is suitably affixed to a conventional I-beam to which is movingly mounted a conventional endless cable and space shackle system for conveying birds in an upside-down manner. The four mounted gears are rotatable in unison by a chain drive which may be manual, hydraulic, pneumatic or electric, whereby the trough may be selectively moved upwardly or downwardly as found necessary to vary the distance between the I-beam and the trough to accommodate different sized shackles and/or birds. The trough has a short extension to provide a first section and a second section. Both sections include a grate through which the bird's head is dragged.

In the first section, a pulsating DC current operating at a relatively low voltage (<NUM>-<NUM> volts) is applied via an electrical connection, such that electricity is applied to a grate in each section. The overhead shackle line carrying the birds is at a polarity which is opposite to the polarity of electricity being supplied to the stainless steel surface submerged in saline solution and the trough. In the second section, a low AC current operating at about <NUM> volts is applied via the electrical connection between the shackles and the trough. The second section of the extension is electrically isolated from the first section of the main or first section of the trough. The speed of the conveyer is such that the poultry are subjected to the low voltage AC current in the extension for a period of only about two to three seconds.

The invention is defined by an apparatus according to claim <NUM>. According to an illustrative embodiment, a poultry stunning apparatus comprises a trough for containing water through which poultry is carried for stunning, the trough having first and second open ends for permitting poultry to be carried along through the trough on an overhead shackle line; an electrical control module configured to apply a DC current to poultry at a voltage sufficient to stun poultry; and a stunning electrode; wherein the stunning electrode is pivotally mounted within the trough by way of one or more hinges and configured for pivotal motion between a lowered, substantially horizontal position and a raised, substantially vertical position; and wherein the stunning electrode comprises a substantially smooth metal plate adapted and positioned within the trough, and a contact zone for contacting poultry as poultry is carried along through the trough, the contact zone of the metal plate being substantially smooth and uninterrupted, wherein the overhead shackle line configured to carry the poultry is at a polarity which is opposite to the polarity of electricity supplied to the metal plate.

Optionally, the electrical control module and a second, independent stunning electrode are configured to apply AC current to stunned poultry at a voltage and for a period of time sufficient to immobilize and relax the muscles of stunned poultry.

Preferably, the trough is made of electrically non-conducting material, such as fiberglass.

In another illustrative embodiment, a poultry stunning apparatus operates such that a DC voltage/current is applied for initial stunning, followed by an AC voltage/current to immobilize poultry and to further relax the muscles of stunned poultry, such that poultry does not exhibit involuntary motions, while at the same time avoiding or minimizing damage to poultry tissue.

In one example embodiment, an apparatus comprises a poultry stunning apparatus, including an electrical control module configured to apply a DC current to poultry at a voltage sufficient to stun poultry and to apply AC current to stunned poultry at a voltage and for a period of time sufficient to immobilize and relax the muscles of stunned poultry, while at the same time avoiding or minimizing damage to poultry tissue.

Optionally, the AC current is applied at a medium voltage of between about <NUM> and <NUM> VAC. Preferably, the AC current is applied at a voltage of between about <NUM> and <NUM> VAC. Most preferably, the AC current is applied at a voltage of between about <NUM>-<NUM> VAC.

In another non-claimed example embodiment, the invention relates to a method for stunning poultry, including the steps of applying a DC current to poultry at a voltage sufficient to stun poultry; and applying an AC current to stunned poultry at a voltage and for a period of time sufficient to immobilize and relax the muscles of stunned poultry, while at the same time avoiding or minimizing damage to poultry.

With reference now to the drawing figures, wherein like reference numbers represent corresponding parts throughout the several views, <FIG> show a direct current/alternating current poultry stunning and immobilizing apparatus <NUM> according to an example embodiment of the present invention. The device generally includes a stunner cabinet <NUM>, an overhead support frame <NUM>, and kill line shackles <NUM> attached to a pre-existing overhead track <NUM>. Such an overhead track <NUM> is a common feature in many poultry processing plants.

According to an illustrative embodiment, an apparatus and method are provided for applying a low voltage DC current to poultry to stun the poultry and then applying an AC current to the poultry at a sufficient voltage and for a sufficient period of time to immobilize the poultry without damaging the tissue.

Referring to <FIG>, which show top and side views of the poultry stunning device <NUM>, including a stunner cabinet <NUM> which forms an elongated U-shaped basin (see <FIG>), the stunner cabinet <NUM> is open at each end to allow poultry to enter the cabinet <NUM> at a first end and exit at the second end. The cabinet <NUM> includes a DC stunner portion <NUM> situated near the first end of the cabinet, and an AC stunner portion <NUM> situated near the second end of the cabinet. The DC stunner portion <NUM> includes a recessed area capable of retaining water. The DC stunner portion <NUM> also includes a DC stunner contact grate <NUM>. In example embodiments, the DC stunner grate <NUM> is positioned at the bottom of the recessed area of the DC stunner portion <NUM>. The AC stunner portion <NUM> likewise includes an AC stunner contact grate <NUM>. The DC stunner grate <NUM> and the AC stunner grate <NUM> are made of electrically conductive material, such as stainless steel. The DC stunner contact grate <NUM> and the AC stunner contact grate <NUM> are electrically isolated from each other. The power supplies coupled to the DC stunner contact grate <NUM> and the AC stunner contact grate <NUM> are protected, for example, by a NEMA 4X stainless steel enclosure.

The stunner cabinet <NUM> also includes a salt water injection system <NUM> located in the DC stunner portion <NUM>. The salt water injection system <NUM> is designed to fill and maintain a level of salt water in the recessed area of the DC stunner portion <NUM>. The salt water injection system <NUM> can include an optional electronic control to ensure the salt water contains the proper saline level for delivering electric current. The cabinet <NUM> can include an optional pneumatic adjustment system to adjust the height of the cabinet <NUM> such that it can accommodate a variety of types and sizes of poultry.

The apparatus <NUM> also includes an overhead support frame <NUM> to support an existing overhead track. The overhead support frame <NUM> supports an overhead conveying track to which kill line shackles <NUM> are connected, as shown in <FIG> and <FIG>. The kill shackles <NUM> are made of electrically conductive material and are designed to support poultry in an inverted position so that the bird hangs upside-down with the bird's head oriented toward the bottom of the stunner cabinet <NUM>. The overhead support frame <NUM> and overhead track <NUM> are suitably affixed to a guide bar system <NUM>, which is movingly mounted to a conventional endless cable and space shackle system for conveying birds in an upside-down manner understood by those skilled in the art. Optionally, an insulated rump bar and breast bar can also be used to support and hold poultry in an inverted position. In other embodiments, the apparatus can include an optional guide bar kit for accommodating plastic shackles.

The apparatus <NUM> can be of a modular construction which allows for additional sections to be added without replacing the entire system. The apparatus can also include a digital display and/or a voltage data logger.

As shown in <FIG> and <FIG>, the stunner control panel consists of a NEMA 4X stainless steel enclosure containing (<NUM>) Simmons DC power packs and (<NUM>) Simmons AC power pack. Also included in the panel is (<NUM>) power conditioner and (<NUM>) primary / secondary DC power pack selector switch.

The DC power pack operates by converting standard AC voltage (<NUM>-<NUM> VAC) to low voltage high frequency DCV. The DC voltage and amperage are displayed through a digital display located on the face of the DC power pack enclosure. The DC power pack also includes a variable transformer to raise or lower the voltage going to the DC stunner grate and an on / off switch. The AC power pack uses standard AC voltage as an input (<NUM>-<NUM> VAC). The applied voltage is displayed through a digital display located on the face of the AC power pack enclosure. The AC power pack also includes a variable transformer to raise or lower the voltage going to the AC stunner grate and an on / off switch.

The stunner controller operates to control the DC and AC voltages applied to the bird, as described herein.

In operation, the legs of the poultry are connected to the kill line shackles <NUM>, and the poultry are conveyed upside-down along the overhead track <NUM> from the DC stunner contact grate <NUM> towards the AC stunner contact grate <NUM>. The salt water injection system <NUM> injects a sufficient amount of salt water into the DC stunner section <NUM> of the stunner cabinet <NUM> such that, as the poultry are conveyed along the overhead track <NUM>, the heads of the poultry are sufficiently submerged in the salt water to cause an electrical connection for a pulsating DC current to flow from the DC stunner grate <NUM> to the kill shackles <NUM>. This electrical connection enables the pulsating DC current to flow through the poultry such that the poultry are stunned effectively.

According to an illustrative embodiment, as the poultry are conveyed toward the AC stunner contact grate <NUM>, the heads of the poultry emerge from the salt water solution. As the head of the poultry comes into contact with the AC stunner contact grate <NUM>, the head of the poultry is damp enough to create an electrical pathway through the poultry for the AC current to flow from the AC stunner grate <NUM> to the kill shackles <NUM>, such that the poultry is immobilized.

The strength (voltage) of the DC current, the strength (voltage) of the AC current, and the dwell time of the AC current may be varied depending upon, e.g., the size of the poultry, etc. For example, the DC current may be applied as a pulsating square wave with peaks between zero volts and about <NUM> volts (<NUM> VDC and <NUM> VDC). Preferably, the DC voltage is cycled as a square wave with a frequency of about <NUM> (cycles per second), with a duty cycle of about <NUM>%, resulting in an average DC voltage of about <NUM> VDC.

Ideally, the lowest AC current is about <NUM> VAC. It should be appreciated that lower AC currents may also work to immobilize the poultry, but not as effectively. Preferably, the dwell time (time of application of the AC current) is between about <NUM> and <NUM> seconds, and most preferably is between about <NUM> and <NUM> seconds. Preferably, the AC current is provided at a frequency of about <NUM>-<NUM>.

According to an illustrative embodiment, the application of DC current followed by AC current in the manner described above is effective to stun and then immobilize poultry and to relax the muscles of the stunned poultry, while at the same time avoiding or minimizing damage to the poultry tissue. This results in a generally "irreversible stun" from which poultry would not normally recover.

In a preferred form, the present invention relates to a method <NUM> as shown in <FIG>, in which according to a first step <NUM> the bird is passed through the stunner apparatus. In the second step <NUM>, the DC voltage is applied to stun the bird. In the third step <NUM>, the AC voltage is applied to immobilize the bird. And in the fourth step <NUM>, the bird exits the stunner apparatus.

As shown in <FIG>, the stunner cabinet <NUM> has a recess for receiving an alternate embodiment stunner/killer electrode plate and trough (shown in broken lines). <FIG> depict an exemplary trough <NUM> and stunner/killer electrode plate <NUM>, according to an example embodiment of the present invention.

As shown in <FIG>, the trough <NUM> has a first side <NUM>, a second side <NUM>, and a bottom portion <NUM>. The trough <NUM> is generally U-shaped or V-shaped. The trough <NUM> is made of any non-conducting material. In example embodiments, the trough <NUM> is made of fiberglass with a smooth, gel coating on all surfaces. As shown in <FIG>, the bottom portion of the trough <NUM> has a drainage hole <NUM> for allowing water and/or waste to exit the trough <NUM>. The bottom portion of the trough <NUM> may also have an opening <NUM> for admitting water and/or other substances into the trough <NUM>. As shown in <FIG>, each end of the trough <NUM> includes a mounting flange <NUM> with a plurality of fastener holes <NUM> for coupling the trough <NUM> to adjacent elements of the processing line. This design allows for modularity of the trough <NUM> so that additional sections can be added without replacing the entire system.

As seen in <FIG>, <FIG>, and <FIG>, preferably the electrode plate <NUM> is pivotally coupled to the trough <NUM> via a piano hinge <NUM>. In example embodiments, the hinge <NUM> is coupled to the first side of the trough <NUM> and to the electrode plate <NUM> using any suitable fastening means (e.g., nuts, screws, bolts, rivets, etc.). The hinge <NUM>, in alternate embodiments, may be integrally formed with the electrode plate <NUM>. Similar to the electrode plate <NUM>, preferably the hinge <NUM> is made of stainless steel. In example embodiments, the coupling of the hinge <NUM> to the trough <NUM> includes a seal for preventing waste and/or water from passing through the first side of the trough <NUM> at the hinge coupling. The hinge <NUM> may be any suitable hinge (e.g., piano hinge, butt hinge, surface-mount hinge, spring-loaded hinge, etc.). In a preferred embodiment, the hinge <NUM> is a continuous piano hinge. The hinge <NUM> allows the electrode plate <NUM> to pivotally rotate between a substantially horizontal, lowered position (as shown in <FIG>) and a substantially vertical, raised position (as shown in <FIG>). The raised position permits easy access for cleaning and/or other maintenance of the trough <NUM>. A shelf <NUM> is positioned on the second side of the trough <NUM> for supporting the electrode plate <NUM> in a level orientation and also preventing the electrode plate <NUM> from further rotation into the bottom portion of the trough <NUM>. In example embodiments, the shelf <NUM> is made of stainless steel. Similar to the hinge <NUM>, in example embodiments, the shelf <NUM> may be coupled to the second side of the trough <NUM> using any suitable fastening means. In addition, a second seal may be utilized to prevent water and/or waste from passing through the second side of the trough <NUM> at the shelf coupling.

Referring to <FIG> and <FIG>, the electrode plate <NUM> is made of electrically conductive material, such as stainless steel. The electrode plate <NUM> has a contact zone <NUM> for contacting the poultry as the poultry is carried along by the overhead conveying track. The electrode plate contact zone <NUM> is substantially smooth and uninterrupted. Optionally, the electrode plate <NUM> also has a plurality of drainage holes <NUM> at the outer edges of the electrode plate <NUM> and outside of the contact zone <NUM>. The drainage holes <NUM> may be any suitable shape and any suitable size for allowing waste and water to pass through.

It is believed that the smooth, uninterrupted contact zone <NUM> of the electrode plate <NUM> provides a greater contact patch with the poultry during stunning. This is believed to minimize damage to the product by spreading the electrical energy being applied to the poultry to a larger area, minimizing localized damage to the product. It also maintains more continuous contact. Note that the birds are traveling along at substantial speed during stunning, such that the use of a grate-style electrode (as is the norm in the industry) results in a non-continuous contact at locations on the bird as the bird moves forward. The smooth, uninterrupted contact patch allows the parts of the poultry in contact with the electrode to remain in continuous contact during the stunning, resulting in improved stunning with less damage to the product.

The trough <NUM> and electrode plate <NUM> are further coupled to an electrical control module (not shown or numbered). In example embodiments, the electrical control module applies a DC current to the poultry via the electrode plate <NUM> at a voltage sufficient to stun the poultry. The DC current may be a pulsating DC current that operates at a relatively low voltage (<NUM>-<NUM> volts). In some embodiments, the electrical control module applies an AC current to the poultry via the electrode plate <NUM> at a particular voltage and for a particular period of time sufficient to immobilize and relax the muscles of the stunned poultry. In example embodiments, the electrical control module is configured to apply a DC current to stun the poultry and an AC current to immobilize the stunned poultry. Similar to the embodiments discussed above (<FIG>), the overhead shackle line carrying the birds is at a polarity which is opposite to the polarity of electricity being supplied to the electrode plate <NUM>. Thus, an electrical circuit, through the body of the poultry is made for stunning and immobilizing the poultry when the bird comes into contact with the contact zone <NUM> of the electrode plate <NUM>.

Claim 1:
A poultry stunning apparatus (<NUM>), comprising:
a trough (<NUM>) for containing water through which poultry is carried for stunning, the trough (<NUM>) having first and second open ends for permitting poultry to be carried along through the trough (<NUM>) on an overhead shackle line;
an electrical control module configured to apply a DC current to poultry at a voltage sufficient to stun poultry; and
a stunning electrode (<NUM>);
wherein the stunning electrode (<NUM>) comprises a substantially smooth metal plate adapted and positioned within the trough (<NUM>), and a contact zone (<NUM>) for contacting poultry as poultry is carried along through the trough (<NUM>), the contact zone (<NUM>) of the metal plate being substantially smooth and uninterrupted, wherein the overhead shackle line configured to carry the poultry is at a polarity which is opposite to the polarity of electricity supplied to the metal plate,
characterized in that the stunning electrode is pivotally mounted within the trough (<NUM>) by way of one or more hinges (<NUM>) and configured for pivotal motion between a lowered, substantially horizontal position and a raised, substantially vertical position.