Abstract:
A filtering system used on a meat injection machine that injects pickling into meat products. The filter consists of a tank and a first and second rotary filter. The first rotary filter uses a wedge wire wound cylinder and augers having flutes that rotate to catch and push away solid particles toward the second filter. The second filter then uses more wedge wire in a whirlpool effect to ensure all solid materials and foam are in the outside of the filter. Injector fluid is then taken from the center of the inside volume of the second filter to be used in injection needles.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     During mechanical injection of meat products, pickling solution is injected into the meat through a multitude of hollow needles, which are repeatedly inserted into the meat to achieve a predetermined percentage addition of solution. Excess solution is collected in a tray beneath the product for use after filtration to remove meat particles.  
         [0002]     Currently available filter systems usually consist of a wedge wire drum, which rotates slowly. The recovered solution runs over the outside of the drum causing liquids to pass between the wires into a tank while the solid particles are scraped off the outside of the drum as it rotates. The solution is then filtered through static filter screens before being pumped back to the needles.  
         [0003]     Often some solution is transferred with the meat particles still in the solution. Furthermore, when filtration is not completely effective in removing particles from the injection pickle solution, the particles end up in the pickle solution that returns to the needles. This particle matter in the solution can cause clogging which has an adverse effect on the percentage injection rate. In addition, filters, particularly static screens, are prone to becoming clogged by the particles remaining in the solution. This causes the need for repeated cleaning to reduce pump starvation, loss in injection pressure, and injection percentage variation.  
         [0004]     Cleaning of static filters without cleaning the whole system can allow solid matter to pass through the filter and clog the system further down stream. Thus, it is a primary object of the present invention to provide a filtering system for the filtering of injector fluids that improves upon the state of the art.  
         [0005]     Another object of the present invention is to provide a filter system that uses the height of flutes on an auger to retain fluid while still transporting solid materials to the end of the filter.  
         [0006]     A further object of the present invention is to provide a filtering system that allows a fluid surface of liquid to be continually strained of foam.  
         [0007]     Yet a further object of the present invention is to improve the effectiveness of a filtration system.  
         [0008]     A further object of the present invention is to provide a filtration system that can be used in filtration applications other than in injection of meat products.  
         [0009]     And still yet a further object of the present invention is to provide a filter that can be back-flushed while the machine is running.  
         [0010]     These and other objects, feature, or advantages of the present invention will be apparent from the specification and claims.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention provides a filtering system that has a filter tank and a first rotary filter consisting of a filtering cylinder with an internal auger. In the application of the invention, both the filtering cylinder and the internal auger rotate together. The filter system further comprises a substantially enclosed second rotary filter that receives solid particles filtered from the first rotary filter. A scraper then removes the solid particles from the outside surface of the secondary filter and a pipe takes the filtered liquid from the inside of the secondary filter. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a side view of a meat injection machine.  
         [0013]      FIG. 2  is a side view of the filtration system of the meat injection machine.  
         [0014]      FIG. 3  is a sectional view of the filtering system of the meat injection machine taken from line  4 - 4  of  FIG. 2 .  
         [0015]      FIG. 4  shows an enlarged side view of the filter system of the meat injection machine showing the scraper. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]     The term fluid, pickle fluid, and liquid are used interchangeably throughout this disclosure and all represent the liquid portion of a liquid and solid suspension. Solid, solid particles, solid material, and meat particles are also used interchangeably throughout this disclosure and represent the solid portion within the liquid of the solid suspension. The terms pickle injection, injector fluid, pickle solution, and suspension are used interchangeably throughout this disclosure and all represent a liquid and solid suspension or mixture.  
         [0017]     As can be seen in  FIG. 1 , the filtration system of the current invention can be found in meat injection machine  10 . Generally the filter system has a first rotary filter  12 , a second rotary filter  14 , a tank  16 , and a pump  18  that receives the filtered pickle injection from the tank  16  and transports the pickle injection to the injector needles  20 . The injector needles  20  are protected by head cover  22  and inject meat product  24  with the filtered pickle injection.  
         [0018]      FIGS. 2-4  show the filtering system of the meat injection machine  10 . The filtering system has a chute  26  that brings an unfiltered pickle solution into the first rotary filter  12 . The first rotary filter  12  consists of a wedge wire wound cylinder  28  having an auger  30 . The auger  30  is attached to an end plate  31  that has a central opening  33  that allows the chute  26  to protrude there through and bayonet slots  32  receive the auger  30  so that the auger  30  fits snuggly within the cylinder  12  and can rotate therewith. Cylinder  28  and auger  30  rotate together and are releasably attached by the quick-release bayonet connection.  
         [0019]     Preferably cylinder  28  has a wedge shaped wire with a flat edge on the inside and a uniform gap between wires of 0.5 mm (0.02 inches). For different applications, wires of different sizes and dimensions are used. For example, for optimizing the filtration process the gap between wires is varied. In another application the cylinder  28  is made of material that has holes instead of wedged wire. Also, auger  30  is made with a uniform pitch spiral or a variable pitch depending on the application. Auger  30  also has flutes (not shown in drawings) that are able to retain fluid while still transporting solid material to the end of the cylinder  28 , and can be of a height that varies along its length to optimize the filtration of liquid through the filtering cylinder  28  or of a uniform height along its length. The Auger can also have uniform pitch along its length or variable pitch along its length to optimize the filtration of liquid through the filtering cylinder.  
         [0020]     A gear  34  is fixed to the second end  35  of first rotary filter  12  and is meshed with a pinion wheel  36  on shaft  38  which is connected to the motor  40  on the meat injection machine  10 . In operation the motor rotates the shaft  38  of pinion  36  causing the gear  34  to rotate.  
         [0021]     The secondary filter  14  is comprised of a wedge wire wound cylinder  42  having an outer surface  45 , a plate  44  that is part of the sidewall of the tank  16  at one end, and a gear  43  at the opposite end that form an interior chamber  53  that is partially submerged in tank  16 . Gear  43  is operably connected to pinion wheel  36  so that the pinion wheel  36  operatively rotates both the first rotary filter  12  and the second rotary filter  14 . Operably attached to the tank  16  is a scraper  48  used to clean the cylinder  42 . Scraper  48  can be a mechanical blade or an air knife. Also attached to the tank  16  is a container  50  for receiving material removed from cylinder  42 .  
         [0022]     A pipe  52  extends outwardly from the plate  44  and is in communication with the interior chamber  53  of the secondary filter  14 . The pipe  52  provides an outlet for the filtered liquid in the interior chamber  53  of the secondary filter  14 . Pipe  52  is operably connected to the pump  18  to transport filtered liquid from the interior chamber  53  of the secondary filter  14  to the injection needles  20 .  
         [0023]     In operation, a pickle fluid having meat particles falls from chute  26  into cylinder  28 . Liquid passes through the gaps between the wires of cylinder  28  and drains into tank  16 , while the solid particles are transported along the length of cylinder  28  by the rotating auger  30 . In one embodiment the auger  30  and filtering cylinder  28  are rotated at different speeds. The solid particles with some excess liquid then falls from the second end  35  of the cylinder  28  onto the outer surface  45  of the second rotary filter  14 . As the cylinder  42  rotates, solid particles collect on the wedge wire and are transported to the scraper  48  where the solid particles are deposited into container  50 .  
         [0024]     As pump  18  draws liquid via pipe  52  from the interior chamber  53  of secondary rotating filter  14  it generates a negative pressure in interior chamber  53 . This draws fluid from tank  16  into interior chamber  53  through cylinder  42 . Any remaining solids in this fluid are deposited on the outer surface  45  of rotating cylinder  42 , which transports them to scraper  48  as it rotates.  
         [0025]     Any foam (protein and fat) floating on the surface of fluid in tank  16  is lifted off as cylinder  42  rotates and it too is transported to scraper  48  which removes it and deposits it into container  50 . Then pipe  52  transports the filtered liquid from the interior chamber  53  of the cylinder  42  to the injection needles  20 . As the pipe  52  transports filtered liquid from the interior chamber  53  of cylinder  42  extra unfiltered liquid is introduced to the tank  16  via the first rotary cylinder  12 , replenishing the fluid lost in the system.  
         [0026]     In one application the filters are backwashed during the operation of the filtering system. To backwash the first rotary filter  12 , an air knife is installed close to the first rotary filter  12 . Similarly, the second rotary filter  14  may be backwashed by placing a nozzle within the second rotary filter. Fluid is pumped at high pressure at the interior of the second rotary filter  14  to back flush it and force particles that may be clogging it back into the tank  16 .  
         [0027]     Thus, a filtering system for the filtering of injector fluids that improves upon the state of the art is disclosed. The filtering system eliminates the need for static filters by using two rotating cylindrical filters. The system also creates a whirlpool effect that allows foam to be continually strained from the surface of the liquid in the tank. This system may be used in a meat pickling process or any other process wherein solid particles are to be filtered out of a liquid. Furthermore, the filters in this system may be back-flushed while the machine in operation. It will be appreciated by those skilled in the art that other various modifications could be made to the device without the parting from the spirit in scope of this invention. All such modifications and changes fall within the scope of the claims and are intended to be covered thereby.