Abstract:
An apparatus and process for naturally recycling poultry carcasses for use as a nutritional supplement, the apparatus generally consists of four modules: an enzymatic digest medium mixing assembly that self adjusts for pH; a mobile grinding assembly mounted on a truck trailer; a digesting and emulsifying assembly which includes a heated tank and separator; and a drying system. Carcasses are loaded into the grinder, and the ground carcasses are pumped into a storage tank with the enzymatic digest medium to produce a protein soluble mixture. The particle size of this mixture is then further reduced, and transported to a centralized and stationary processing plant for digesting and emulsifying. The remaining emulsified proteins are then dried. The resulting pellet-like pieces are uniformly sized for packaging.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to naturally recycling protein waste into feed and, more specifically, to an apparatus and process for enzymatically digesting, emulsifying and drying protein waste including feathers for use in animal feed. 
     2. Description of the Prior Art 
     A mass of waste is accumulated on a regular basis in such operations as poultry production facilities. Protein waste such as carcasses from animal production facilities pose problems for disposal. Carcasses are currently disposed of in many ways including land filling and burning. Natural gas production from waste materials is also known in the art and such processes typically also result in a byproduct which is used as animal feed or fertilizer. Some facilities process the protein waste to produce a component for animal feed but these plants often are not designed to provide a mostly closed system and, consequently, air, moisture, and other contaminants may enter creating an environment where microorganisms can multiply and destroy the quality or usefulness of the processed protein waste. 
     And, although there may be processing plants at which protein waste may be disposed and recycled, there is not an efficient way to remove the waste from the site to the processing plant in such time and condition as necessary for efficient processing. The timing of such disposal is essential to managing toxicity and odors yet it is not feasible for each animal production plant to also operate a processing plant for its protein waste. 
     Animal feed requires a protein component. In addition to the carcasses which can be processed for protein recovery, feathers are inexpensive and also high in protein, however, feathers are difficult for animals to digest. And, although there are processes known for forming feather meal, often these processes require steam which, if too hot, will denature the proteins in the feathers and reduce their nutritional values. It is also known that certain bacterial strains produce keratinase which is an enzyme capable of degrading feathers and that, properly employed, such degradation can result in material that can be used in animal feeds. See U.S. Pat. Nos. 4,908,220; 4,959,311. 
     In addition, it is known in the art to provide a means to grind swine or poultry waste and then mix it with ingredients that will facilitate fermentation of the protein waste. See U.S. Pat. No. 5,713,788. The invention disclosed therein provides a specific grinding mechanism which includes a grinding drum with a helical groove on its outer surface in which a length of chainsaw chain, teeth side out, is positioned. This invention also does not include a way to re-circulate and thoroughly mix the ground protein and catalyst but, instead, depends on a metered application of catalyst to the ground protein waste as it moves past the grinder wherein the metering of the catalyst is triggered by the load on the grinder. This is deficient in that no additional mixing of the ground protein waste and catalyst is contemplated such that there is substantial risk that it will not be appropriately mixed and the catalytic action will be hampered. 
     What is needed is a way for the animal production facilities to efficiently and timely dispose of animal waste in such a way that is non-toxic and odor free. In addition, the system has to be affordable for the animal production facilities and the resultant recycled product must be usable. Preferably, a mostly closed system should be used to eliminate environmental contaminants and to provide avenues for recycling by-products. Finally, for any disposal of feathered animals, the system must provide a method of breaking down not only softer protein sources, but also feathers and in a manner that does not denature or destroy the food value of the proteins. 
     The first objective of the present invention is to provide a system wherein animal protein waste is processed in such a way that a portion of the system may be mobile and can be taken from one animal production facility to another or simply positioned at one facility until it reaches capacity; 
     The second objective of the present invention is to provide a protein processing system which is capable of degrading feathers without destroying their food value; 
     The third objective of the present invention is to provide a way for many different and maybe distant animal production facilities to have routine access to a processing facility; 
     The fourth objective of the present invention is to use natural means for recycling and breaking down the animal protein wastes and to recycle by-products of the process; 
     The fifth objective of the present invention is to provide an apparatus that provides mixing and grinding capabilities associated with one another in a manner that results in a mostly closed system which is an efficient process for digesting, emulsifying and drying the recycled protein waste while also providing a means for recycling other byproducts such as water and for minimizing growth of bacteria and other damaging microorganisms. 
     SUMMARY 
     The present invention provides an apparatus and process for naturally recycling poultry carcasses for use as a nutritional supplement. The apparatus generally has four modules: 
     1. a pH adjustable enzymatic digest medium mixing assembly, 
     2. a mobile grinding assembly mounted on a truck trailer, 
     3. a digesting and emulsifying assembly which includes a heated tank and separator, 
     4. and a drying system. 
     The enzymatic digest medium of the preferred embodiment includes protease/keratinase, inedible egg, water, and a preservative. The digest medium mixing assembly is equipped with a pH probe and monitor which triggers the addition of an acidic solution as needed to adjust the pH of the enzymatic digest. 
     The mobile grinding assembly can be moved from one animal production facility to another or can remain at one facility. The mobile grinding assembly of the preferred embodiment is mounted on a trailer and includes a holding tank for the enzymatic digest medium and a conveyor for loading carcasses into a grinder. The remainder of the grinding assembly is a closed system. Once through the grinder, the ground carcasses are pumped into a storage tank with the enzymatic digest medium to produce a protein solubles mixture. This mixture is then recirculated through a chopper pump for a few minutes to further reduce particle size of the ground protein waste and assure adequate mixing of the digest and the proteins and then pumped into a tanker truck for transport. Multiple batches of the protein solubles mixture can be generated so that the storage tanks are filled and emptied as many times as necessary until all the waste has been disposed. Then, the mobile grinding assembly can be moved to another location or it can simply remain until it is needed again. 
     The protein solubles mixture created by the mobile grinding assembly is then moved to a centralized and stationary processing plant and transferred from the tanker truck to the digesting and emulsifying assembly. The enzyme digest in the protein solubles mixture works best between about 100 and 130 degrees Fahrenheit. Therefore, the digesting and emulsifying assembly heats the mixture if needed and only periodically recirculates it until the enzymatic digest has altered the protein solubles to a mostly liquid state. The digested protein solubles are then run through an emulsifier to completely disperse the fats and proteins. The digested and emulsified proteins are then pumped into a separator tank and the bottom layer of water is drained off periodically, leaving the emulsified proteins. The water layer is then recycled back to the portion of the system where the enzymatic digest is made. The remaining emulsified proteins are then transferred to the drying system. 
     The dryer system uses a carrier for surface absorption of moisture, extrusion, air flow, and heat to accomplish the removal of moisture. A carrier such as cereal, soybean meal, corn or wheat mids is fed through a volumetric feeder to a mill where it is finely ground to provide ample surface area for absorption. The carrier is then conveyed to a mixer where it is mixed with the emulsified proteins until a doughlike consistency is reached. At this point, the dough is fed into an extruder to remove additional moisture and to extrude dough pellet-like pieces which are then moved by oscillating belt to the drying apparatus. 
     The drying apparatus includes a dryer bed which, in the preferred embodiment, is a conveyor belt enclosed in a housing. The housing alternates air flow direction and has heat zones for removing yet more moisture content and a cooling zone to return the pellet-like pieces to near room temperature. The pellet-like pieces are moved progressively through the air flow, the heat zones and the cooling zone by the conveyor. Next, the pellet-like pieces are sized and then run over a vibrating screen to separate the fines and overs. Finally, the appropriately and uniformly sized pellet-like pieces are packaged. 
     Other objects, features, and advantages of the present invention will be readily appreciated from the following description. The description makes reference to the accompanying drawings, which are provided for illustration of the preferred embodiment. However, such embodiment does not represent the full scope of the invention. The subject matter which the inventor does regard as his invention is particularly pointed out and distinctly claimed in the claims at the conclusion of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the mobile grinding assembly portion of the present invention; 
         FIG. 2  is a diagram showing the enzymatic digest mixing assembly portion of the present invention; 
         FIG. 3  is a side view of the mobile grinding assembly portion of the present invention; 
         FIG. 4  is an enlarged plan view of the mobile grinding assembly of  FIG. 3 ; 
         FIG. 4   a  is an enlarged cross-sectional view of the grinder of the grinding assembly of  FIG. 4 ; 
         FIG. 5  is a side view of the digesting and emulsifying assembly portion of the present invention; 
         FIG. 6  is a block diagram showing the components of the dough mixing apparatus and extruder of the drying system portion of the present invention; 
         FIG. 7  is a block diagram of the drying apparatus of the drying system portion of the present invention; 
         FIG. 8  is a flow diagram showing the components of the apparatus for natural recycling of protein waste of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     The apparatus and process for naturally recycling protein waste of the present invention comprises an enzymatic digest mixing assembly shown generally as  15  in  FIG. 2 , a mobile grinding assembly shown generally as  40  in  FIGS. 3 and 4 , a digesting and emulsifying assembly shown generally as  100  in  FIG. 5 , and a drying system shown generally as  120  in  FIGS. 6 and 7 . 
     DETAILED DESCRIPTION 
     In general, the process is shown in  FIG. 2  and  FIG. 8  and requires that an enzymatic digest medium  18  of a particular pH level be prepared and stored until such time as it is needed. The medium of the preferred embodiment comprises enzymes  204 , inedible egg  206 , a preservative  208  and water. The enzymes  204  may include protease to break down and digest most proteins, and keratinase to aid in digestion of feathers and the preferred embodiment contemplates a mixture of preservative 2 lbs/ton, enzyme 1½ lbs/ton, and the remainder per ton of inedible egg. The preservative  208  restricts multiplication of bacteria or microorganisms which could adversely affect the end product. An example of one such preservative  208  is sodium meta-bisulfite. Although inedible egg is a logical choice when the apparatus is used in conjunction with poultry production, other fluid wastes such as outdated ice cream, molasses, milk by products, and others that include proteins, fat, and water could be appropriately substituted. 
     In the preferred embodiment, the pH is adjusted by measured addition of phosphoric acid  36  to maintain an optimal level of pH 5 or within the range of about 4-6. Using phosphoric acid  36  to effect a change in pH also adds phosphorous to the medium and, in turn, provides a high phosphorous product which may enhance the desirability of the additive for animal feed. Other acidic solutions may also be used. For example, lactic acid is one such reasonable alternative. In the case where lactic acid is used, the fermentation process which occurs as a natural consequence of the use of lactic acid, (in addition to digestion by enzymes) also acts to break down the protein waste and lowers the pH at the same time. 
     Protein waste in the form of spent hens  216  is then ground and the enzymatic digest medium  18  and ground protein waste  41  are thoroughly mixed and re-circulated through a chopper pump  88  to produce a protein solubles mixture  84 . The protein solubles mixture  84  is maintained at or heated to a temperature optimal for enzyme digestive action which ranges between about 90 degrees Fahrenheit and 110 degrees Fahrenheit and recirculated periodically until the mixture is mostly liquid. The heat created by the exothermic digestive process and the friction of recirculation in certain conditions may be enough to maintain the optimal temperature and, if not, additional heat can be provided. The preferred method suggests recirculating the mixture for 1 hour every 12 hours for 3-4 days, however, the speed of the process may be increased if additional enzyme is used. When the protein solubles mixture  84  can be strained and the number of quills remaining in the strainer is acceptable, the digestion is complete. The protein solubles mixture  84  is then emulsified to disperse fats and proteins and allowed to separate. The resulting water layer  114  is drained off and recycled to be re-used for mixing enzymatic digest medium  18  and, after draining the water layer  114  several times, the emulsified proteins  110  is mixed with a carrier  132 . 
     The carrier  132  is delivered to a high speed mixer  140  by volumetric feeder  130  and comprises a relatively high surface area to volume ratio which acts to absorb some of the moisture. Upon mixing with said emulsified proteins  110 , a doughlike mixture  144  is produced. The doughlike mixture  144  is then extruded into a plurality of pellet-like pieces  146  and the pellet-like pieces are passed through a drying apparatus  126  which uses air flow, multiple heat zones, and at least one cooling zone for further removal of moisture. The pellet-like pieces are finally sized through a roller mill  166  to a uniform, granular size. The off-size pellet-like pieces are removed and the remaining uniform, granular pellet-like pieces can be packaged. The apparatus used to accomplish the foregoing process is described below. 
     The enzymatic digest mixing assembly  15  shown best in  FIG. 2  is used to mix enzymes  204 , inedible egg  206 , and a preservative  208  with water to form an enzymatic digest medium  18  of an optimal pH level  19  and comprises at least one enzymatic digest mixing tank  22 , pumping means  24 , a re-circulating assembly  26  and means for adjusting the pH level of the medium which, in the preferred embodiment, is a pH adjustment assembly  28 . Said pumping means  24  of the preferred embodiment comprises a first centrifugal pump and said re-circulating assembly  26  comprises a first inductor nozzle  27  associated with said pumping means  24  and a return pipe  29  for circulating the enzymatic digest medium  18 . The preferred embodiment includes load cells  25  associated with a digital scale  25   a  and positioned such that addition of the enzymes, preservatives, inedible egg can be measured. It is also contemplated that, in addition to external measuring of the ingredients, other internal measurement options such ultrasound and light beams may be used to monitor the amounts of each ingredient as it is added. 
     Said pH adjustment assembly  28  of the preferred embodiment comprises a pH probe  30 , a pH monitor  32 , and a first positive displacement pump  34  all electrically associated, and a supply of acidic solution  36  fluidly connected to said positive displacement pump  34  and to said mixing tank  22  through a check valve  38 . Said first positive displacement pump  34  of the preferred embodiment includes a variable speed motor, preferably pumping 1-10 gallons per minute. Once said enzymatic digest medium  18  is placed in the mixing tank  22  and recirculated for at least 3-5 minute, said pH probe  30  provides pH level  31  to the pH monitor  32 . The pH monitor  32  compares the pH level  31  with the optimal level  19  and sends a signal to the positive displacement pump  34  to move said acidic solution  36  into said mixing tank  22  where recirculation continues. The re-circulating assembly  26  continues to mix the enzymatic digest medium  18  and the pH probe  30  again measures the pH level  31 , the monitor  32  compares the level  31  to the optimal level  19 , and again determines whether acidic solution  36  should be added to the mixing tank  22 . When the pH level  31  reaches the optimal level  19 , the enzymatic digest  18  is ready to be used or stored. 
     The enzymatic digest medium  18  of the preferred embodiment includes, per ton, about 2½ pounds of protease and keratinase  204 , about 2 pounds of preservative  208 , and the remaining pounds inedible egg and water  206 . The pH is lowered to about 5 by addition of phosphoric acid  36 . This pH level is optimal for this particular enzymatic digest medium, however a range from about 4-6 may be effective and the amount of enzyme may be altered according to the speed of digestion desired and the enzymes used. 
     Once said enzymatic digest medium  18  has been prepared, it can either be stored or it can be moved via tanker truck  37  to the mobile grinding assembly  40  where it will be mixed with ground protein waste  41 . Referring now to  FIGS. 3 and 4 , said mobile grinding assembly  40  comprises a movable platform  42  which, in the preferred embodiment, is a semi trailer, and includes a front portion  43 , a mid portion  44  and a rear portion  45 , a conveyor belt  56  for moving protein waste, a holding tank  58  in which said enzymatic digest  18  is stored, at least one prep tank  60 ,  62 , and a pump  64  to move said enzymatic digest medium  18  from said holding tank  58  to said at least one prep tank  60 ,  62 . Said mobile grinding assembly  40  further comprises grinding means  66  which, in the preferred embodiment, (shown in  FIG. 4   a ) comprises a grinder inlet  67  positioned near said conveyor belt  56 , a grinder plate  68 , and a grinder outlet  69  and at least one grinder knife  70  wherein said grinder outlet  69  is positioned such that output from said grinder outlet  69  may flow by closed connection  71  into a hydro pump  82  said hydro pump  82  having a lower outlet  74 . A specific example of grinding means  66  is a Weiler Meat Grinder utilizing a 7/16″ plate. However, different plate combinations can be used such as double-cut, double-knife combinations with a ¾″ or ⅜″ plate. In this situation, one knife is positioned on the inside of the grinder plate  68  and another on the outside of the grinder plate  68 . 
     Said grinding assembly  40  further comprises mixing means  80  which, in the preferred embodiment, comprises at least one second positive displacement pump  72 , which is fluidly connected to said at least one prep tank  60 ,  62  and to said hydro pump  82  of the grinding means  66  such that said enzymatic digest medium  18  can be moved to said hydro pump  82  where said output  70  from said grinder outlet  69  is mixed with said enzymatic digest medium  18  to form a protein solubles mixture  84 . Said enzymatic digest medium  18  is pumped against said grinder outlet  69  and washes ground protein waste down into the hydro pump  82 . Said lower outlet  74  of said hydro pump  82  is fluidly connected to a suction side  86  of a centrifugal chopper pump  88  which is further associated with said at least one prep tank  60  or  62  and a recirculation piping system  90  including an inductor nozzle  92 . This arrangement provides a way to move said protein solubles mixture  84  through said chopper pump  88  and into said prep tank  60  via said inductor nozzle  92  which is positioned to generate a circular flow in said prep tank  60 . The mixture  84  is continually recirculated through the chopper pump  88  until it is of desired consistency and thoroughly mixed. This usually requires several minutes. 
     The protein solubles mixture  84  is then transported to said digesting and emulsifying assembly  100  shown in  FIG. 5  either via pumping it directly or by pumping it first to a tanker truck  94  and then to the assembly  100 . The mobile grinding assembly  40  is a closed system wherein the grinder inlet  67  is the only input open to the environment. 
     Where more than one prep tank  60 ,  62  is present, one prep tank  60  may be recirculated or unloaded while another is being filled and recirculated. In this embodiment, a separate chopper pump is associated with each prep tank. 
     In one embodiment, said front portion  43  of said movable platform  42  is occupied by a power source  75  in the form of a generator, said mid portion  44  of the movable platform  42  accommodates the holding tank  58  and prep tanks  60 ,  62 , and said rear portion  45  includes said grinding means  66  and said conveyor belt  56 . Said at least one prep tank  60 ,  62  of the preferred embodiment is a cone-bottomed tank. 
     Said digesting and emulsifying assembly  100  of the preferred embodiment is stationary rather than mobile. The digesting and emulsifying assembly  100  comprises a digester tank  102  for digesting said protein solubles mixture  84 , a heating means  103  and recirculation means  104  for periodic mixing including a chopper pump  105 , and an emulsifier  106  fluidly connected to a pump  107 , said digester tank  102 , and a separator tank  108 . 
     In the preferred embodiment, said digester tank  102  is cone-bottomed wherein the cone-bottom  115  is enclosed in a housing  116  and said heating means  103  comprises water  117  enclosed in said housing  116  which is heated by a heating element  118  to about 120 degrees Fahrenheit. In turn, the protein solubles mixture  84  is also warmed to a temperature ranging from about 90 degrees Fahrenheit to 110 degrees Fahrenheit. The protein solubles mixture  84  is recirculated while it digests approximately 1 hour every 12 hours and for a total of 3-4 days. In certain conditions, the heat produced by the circulation friction and the exothermic digestive process may provide enough heat to maintain the digest medium at optimal temperature reducing or negating the need for adding heat. 
     Once digested, said protein solubles mixture  84  is pumped into said emulsifier  106  to suspend fats and proteins and produce emulsified proteins  110  which are then transferred to said separator tank  108 . An example of an emulsifier suitable for this purpose in the Mincemaster Dual Plate. Said separator tank  108  comprises a closeable opening  112  fluidly associated with said enzymatic digest medium mixing tank  22  such that as a water layer  114  forms in said separator tank  108 , it can be drained out and recycled for use in mixing additional digest medium  18 . 
     Referring to  FIGS. 6 and 7 , the emulsified proteins  110  are moved to said drying system  120  which comprises a dough mixing apparatus  122 , an extruder  124  and a drying apparatus  126 . The dough mixing apparatus  122  of the preferred embodiment shown in  FIG. 6  comprises a volumetric feeder  130  for measuring an absorbing carrier  132  to be mixed with said emulsified proteins  110  and which is positioned over a mill  134  for finely grinding said absorbing carrier  132 . The mill  134  of the preferred embodiment is a high speed hammer mill or disc mill. A second conveyor belt  136  moves said absorbing carrier  132  from said mill  134  to a high speed continuous mixer  140 . A third positive displacement pump  142  is associated with said separator tank  108  and moves said emulsified proteins  110  to said high speed mixer  140  where it is mixed with said absorbing carrier  132  to produce a doughlike mixture  144 . In the preferred embodiment, said absorbing carrier  132  is a substance with characteristics like wheat mids, soybean meal, corn, or a previously dried material made for such purpose and the third positive displacement pump is of the variable speed variety. 
     The doughlike mixture  144  is moved to said extruder  124  which pressure-forces moisture out of the doughlike mixture  144  and produces a plurality of pellet-like pieces  146 . In the preferred embodiment the pellet-like pieces are 3/16″ and of random length. Said pellet-like pieces  146  are extruded onto an oscillating belt  148  which distributes the pellet-like pieces  146  evenly and connects said extruder  124  to said drying apparatus  126 . Additional moisture is removed by the drying apparatus  126  using heat and air movement. Said drying apparatus  126  shown best in  FIG. 7  comprises a dryer bed  150  positioned to receive said pellet-like pieces  146  from said oscillating belt  148 , a housing  152  through which a dryer bed conveyor belt  154  moves and conveys said pellet-like pieces  146  and which includes at least one heating zone  156 ,  158 ,  160 , at least one cooling zone  162 , and means to direct airflow  164 . A roller mill  166  receives said pellet-like pieces  146  after they emerge from said housing  152  and sizes said plurality of pellet-like pieces  146  to a uniform size. A vibrating screen  170  is used to remove any of said plurality of said pellet-like pieces  146  which are of a non-uniform size. Means to direct airflow  164  may comprise fans positioned to alternate the flow of air to provide uniformity in drying. In the preferred embodiment, said heat zones  156 ,  158 ,  160  provide temperatures of  300 ,  275 , and  250  Fahrenheit, in this order, such that the maximum temperature of the plurality of pellet-like pieces does not exceed  250 . If the heat of the pellet-like pieces  146  exceeds this level their taste can be too bitter and the amino acids can be degraded. The cool zone  162  returns the pellet-like pieces  146  to within 10 degrees of ambient temperature. Vents  171  return the heated air from the cool zone  162  to the heat zones. 
     Thus, the present invention has been described in an illustrative manner. It is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. 
     Many modifications and variations of the present invention are possible in light of the above teachings. For example, it may be possible for all parts of the system to be made in mobile form or for none of the system to be mobile. Many different pumps are available and may be used according to need. The enzymatic digest medium can be altered to accommodate different protein/bone/feather combinations. Therefore, within the scope of the appended claims, the inventor so defines his invention: