Patent Publication Number: US-2006009142-A1

Title: Plant and method for the stunning and killing of animals for slaughter through asphyxiation

Description:
REFERENCE TO EARLIER APPLICATION  
      This Application incorporates by reference and claims the benefit of Italian Patent Application No. BS2004A000075, filed Jun. 25, 2004, by Cattaruzzi, entitled Plant And Method For The Stunning And Slaughter Of Animals For Through Asphyxiation.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention refers to a plant and a method for the stunning or killing of farmyard animals such as chickens, turkeys, ducks, geese, pheasants, and rabbits destined for slaughter.  
      2. Discussion of Related Art  
      The methods currently used to stun and/or kill animals for slaughter include electrocution, shooting, electro narcosis, concussion and exposure to carbon dioxide.  
      An example of gas use to stun or kill poultry is described in patent no. EP 0 680 259 B1. This system, although advantageous for its efficiency and ability to reduce the damage which birds sometimes incur by flapping their wings, also has some inconveniences: 
          the presence of dangerous gas storage plants in or around the slaughterhouse;     the high construction cost of such plants, which makes their utilization difficult for small and medium sized companies;     the need to take considerable precautions in plant management, especially in the case of forced interruptions to the processing line;     loss of all animals already killed following a breakdown of the gas plant, due to the impossibility of immediate intervention inside the gas chamber;     difficulty in correct calculation of the quantity of gas to pump into the gas chamber in proportion to the animals&#39; weight.        

     SUMMARY OF THE INVENTION  
      The aim of the present invention is to supply a stunning and killing method with the advantageous characteristics of the systems utilizing gas but with none of the above-mentioned defects. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The characteristics and advantages of the plant of the invention will be more easily understood from the description below of its preferred embodiments, in conjunction with the appended indicative and non-limiting drawings, in which:  
       FIG. 1  illustrates a schematic view from the top of the plant in a first embodiment;  
       FIG. 2  shows the plant from the side;  
       FIG. 3  is a schematic view from the top of the plant in a second embodiment;  
       FIG. 4  shows the plant from the side;  
       FIG. 5  illustrates a schematic view from the top of the plant in a third embodiment;  
       FIG. 6  shows the plant in  FIG. 5  from the side;  
       FIG. 7  shows a cross section of the plant across the line A-A in  FIG. 5 ;  
       FIG. 8  is a view from the sides of the plant embodiments in  FIGS. 5-7 ;  
       FIG. 9  illustrates a schematic view from the top of the plant of a fourth embodiment;  
       FIG. 10  shows the plant in  FIG. 9  from the side;  
       FIG. 11  is a schematic view from the top of the plant of a further embodiment; and  
       FIG. 12  shows a cross section of the plant across the line A-A in  FIG. 11 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      In its general embodiment, as illustrated in  FIGS. 1 and 2 , the stunning and/or killing plant for animals for slaughter described in this invention comprises a hermetically sealable chamber  10  with at least one aperture  10 ′ for introduction of live animals and removal of stunned or killed animals, devices for hermetic sealing of said aperture/s, and an extraction means  15  communicating with and extracting air from said chamber in order to stun or kill the animals.  
      Preferably, the chamber  10  has an entrance aperture  11  for introduction of live animals and an exit aperture  12  for removal of stunned or killed animals, each aperture having its respective closure device  13 ,  14 .  
      In this case, the bottom of the hermetically sealable chamber  10  advantageously consists of a motorized conveyor  17  capable of transporting the animals from entrance  11  to exit  12 . This allows the simultaneous loading of live animals into and removal of stunned or killed animals from the chamber  10 .  
      The animals may be introduced into the plant enclosed in a single container  27 , or in a succession of crates  16 , or loose.  
      Where animal movement is in a line of crates  16  or loose, the hermetically sealable chamber is in the form of a tunnel.  
      Advantageously, in order to automate the phases of animal loading into the chamber  10 , stunning and/or killing and removal, the live animals are transported from a loading zone (not shown) to the hermetically sealable chamber entrance aperture  12  by a motorized entrance conveyor  18 . In the same way, the stunned or killed animals are transported to the exit aperture by a motorized exit conveyor.  
      Where the single container  27  is utilized, it can be simply inserted and removed from the chamber  10  with a lift truck.  
      In the embodiment shown in  FIGS. 1-4 , for example, the hermetically sealable chamber  10  is designed to hold one or more containers  27  simultaneously. In  FIGS. 3 and 4 , the containers  27  are introduced into the chamber by a motorized entrance conveyor  18  and removed by the motorized exit conveyor  19 . Once removed, each container  27  is activated to turn on its side to unload the killed animals onto a third motorized conveyor  28  serving a hanging line  29 .  
      In accordance with a preferred embodiment, numerous perforated pipelines  20  connected to the extraction means  15  are positioned inside the hermetically sealable chamber  10 . These perforated pipelines  20  run along the entire hermetically sealable chamber  10  and are distributed along its floor, side walls and ceiling.  
      The extraction means  15  comprises, for example, an electric pump connected to the perforated pipelines by a duct  15 ′.  
      In the embodiment shown in  FIGS. 1-7 , the aperture closure devices  13  and  14  are in the form of a rolling shutter.  
      Alternatively, as shown in  FIGS. 8-10 , the closure devices  13  and  14  may be in the form of pivoting plates which can be activated to rotate between a raised position, or closure of apertures  11  and  12 , and a lowered position, or opening of the connection between the motorized conveyors  18 ,  17 ,  19 . The latter may be, for example, belt conveyors. In this case, to facilitate animal throughput, especially where they are introduced loose into the plant, the motorized entrance  18  and exit  19  conveyors are positioned respectively above and below the motorized conveyor  17  of the sealable chamber  10  ( FIG. 8 ).  
      As another alternative, the entrance and exit closure devices may be of a revolving door type, allowing a continuous throughput of animals through the hermetically sealable chamber  10 .  
      In any case, the closure devices  13 ,  14  are preferably actuated using electric, pneumatic or hydraulic commands.  
      The animal stunning and/or killing method using the above described plant thus involves the introduction of the animals into the sealable chamber  10 , closure of the entrance and exit apertures and activation of the extraction means to create a vacuum within the chamber  10 . Tests effected have demonstrated that a vacuum of 60 mm Hg maintained for 120 seconds will cause the death of the animals, which can then be immediately sent to the hanging area for the subsequent throat-cutting and blood draining phases. Preferably, while the stunned or killed animals are being removed from the sealable chamber  10 , other live animals are simultaneously introduced into the chamber.  
      If required by the overall abattoir capacity, i.e. if its hourly production requires a number of animals greater than that exiting the stunning/killing plant, to avoid dead time due to the animals&#39; stay in the sealable chamber under vacuum conditions for the pre-established time, the stunning/killing plant can be set up in such a way as to optimize loading, air extraction from the hermetically sealable chamber and removal, in order to achieve the greatest possible throughput of animals to the hanging zone.  
      Specifically, if N is the number of animals that the processing line after the stunning/killing plant is able to process in one unit of time, and T is the time necessary to stun/kill the animals, to enable the continuous operation of the processing line without interruption the sealable chamber must be big enough to contain at least N*T animals (ignoring for the sake of simplicity the time needed to transfer the stunned or killed animals exiting the sealable chamber to the hanging line).  
      In this way, there will always be stunned or killed animals ready to be supplied to the hanging line.  
      Nevertheless, in contrast to the plants utilized to date, the need to hermetically seal the chamber from which air is extracted means that continuous throughput of animals from the entrance to the exit of the stunning/killing by asphyxiation plant is not possible. Even in the above cited case, in which the capacity of the stunning/killing plant allows the hanging line to be re-supplied without interruptions, there is the inconvenience that the newly stunned or killed animals are not immediately hung on the processing line but wait for a time up to the time T necessary for stunning/killing. This situation may not be acceptable for correct animal processing, which requires the shortest time possible between the animal&#39;s death and its throat-cutting and blood-draining.  
      The following solutions to avoid this problem employ a number of hermetically sealable chambers serving the same hanging line, each one with a capacity lower than the N*T capacity defined above. These chambers can be activated independently with a temporal sequence dependent on their number and capacity. Increasing the number of hermetically sealable chambers reduces the maximum waiting time for animals to be hung on the processing line.  
      For example, again referring to the T and N values defined above, using two chambers each with capacity T*N/2 animals, the second chamber can be activated at T/2 time after the first is activated. The maximum waiting time for animals exiting the chamber is thus reduced from T to T/2.  
      In the embodiment shown in  FIGS. 9 and 10 , the hermetically sealable chamber  10  is supplied with at least one intermediate closure device  22  suitable for dividing at least two compartments  23 ,  24 , connected in cascade and hermetically separable from one another.  
      It is thus possible to introduce the first group of animals into the first compartment  23 , close all the closure devices  13 ,  14  and  22  and activate the extraction means  15 . After time T′ less than that necessary to stun or kill the animals, the intermediate closure device  22  is opened so that the first group of animals can be transferred to the second compartment  24 . The intermediate closure device  22  is then re-closed and the entrance aperture  11  opened. A second group of animals can now be introduced into the first compartment  23  and the entrance aperture  11  closed; while the second group remains in the first compartment for time T′, the exit aperture  12  can be opened and the first group of stunned or killed animals removed. The cycle is repeated from the closure device  22  opening phase.  
      Such a plant allows the exit motorized conveyor  19  to be re-supplied at time intervals T′ shorter than the time T necessary for the animals&#39; stunning or death. Obviously, increasing the number of compartments in cascade allows ever shorter waiting times to be achieved for animals exiting the stunning/killing plant.  
      A further variant on the embodiment is shown in  FIGS. 11 and 12 , where the hermetically sealable chamber comprises at least two compartments  25 ,  26  positioned in parallel, that is with each one connected to its own extraction means  15  and having its own entrance and exit apertures with their respective closure devices.  
      Construction of the chamber  10  with parallel compartments allows phase initiation of successive compartments to be delayed with respect to the first, thus supplying the most continuous possible throughput of stunned or killed animals to the plant exit.  
      In all the embodiments described above, the plant advantageously comprises a control unit (not shown) able to activate and synchronize the extraction means, the closure devices and the motorized conveyors.  
      Chamber  10  capacity and conveyor speed and length are in any case chosen on the basis of the capacity of the slaughterhouse, in order to guarantee both the shortest time possible between the animal&#39;s death and its throat-cutting and blood-draining and the continuity of the processing line. In other words, the number of animals within the stunning/killing plant must be equal to or greater than the number of animals hung up on the plant line in one unit of time.  
      It should be noted that the described plant, as well as being financially advantageous, is also safer than plants utilizing gas. In the case of a breakdown, for example, one need only stop the pump in order to restore normal environmental conditions through a venting valve in only a few seconds, thus safeguarding both the animals in the chamber and any worker who must intervene.  
      Obviously, to satisfy contingent and specific requirements, a person skilled in the art could make further modifications and variations to the plant described in this invention, all however contained within the scope of the invention, as defined in the following claims.