Abstract:
An apparatus and method is provided for organic material reduction and preparation for subsequent recycling or disposal in a self-contained system which is safe for equipment operators, and highly cost and floor-space efficient. The apparatus includes a preferably-shaped hopper for receiving organic materials to the reduced, preferably a floating auger, a solids pump and a macerator. The system preferably generates a processed organic material discharge with a particle size on the order of ⅛″ without concern as to the liquid content of the incoming organic material. The apparatus may be operated by a method which is completely automated following operator initiation, including automatically attempting self-clearing actions in the event of detecting clogs or jams in the processing components.

Description:
[0001]    The present application is a continuation-in-part of application Ser. No. 13/480,158, filed on May 24, 2012. 
     
    
       [0002]    The present invention relates to an apparatus and method for processing organic materials such as food waste. In particular, the present invention relates to organic material reduction and preparation for subsequent recycling or disposal in a self-contained, automated system which is safe for equipment operators, highly cost and floor-space efficient, and highly scalable for use in both large and small facilities, such as retail store back-room operations. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the field of waste processing, recycling and disposal, organic material disposal is a source of numerous challenges. 
         [0004]    Food products difficult due to wide variety of shapes, sizes, textures, variations in density in internal and external regions, and variations in water content. For example, bread products present a particular problem for automated waste disposal due to their low moisture content and constituents which tend to be self-adhesive and jam mechanical devices, unless substantial water is added to the bread shredding process. 
         [0005]    Another difficulty in organic waste stream processing is providing a single material handling arrangement which can simultaneously and efficiently handle organic materials as diverse as small, soft tomatoes and large, smooth surfaced watermelons, where watermelons tend to simply “ride” on top of material handling equipment sized to handle smaller organic materials. Similarly, the single mechanical arrangement must be capable of providing a consistent flow of material into the processing equipment to provide for efficient and smooth operation of the downstream organic material reduction equipment and to avoid problems with blockages forming in the equipment. Water may be injected into the organic material to help avoid clogging and to otherwise lubricate and cool components during processing, however, this approach has several disadvantages, including requiring provision of piping and connection to a water source, use of large volumes of water (water which continues to increase in cost and may relatively scarce in some regions), and increasing the volume of processed material ultimately requiring disposal at a time in which the cost per unit volume of waste disposal at commercial and municipal facilities is rapidly rising. Further, even where water may be readily available, its use reduces the breadth of organic materials which may be processed, as some materials are not amenable to addition of water during processing. Moreover, water is a costly resource and its use reduces savings from recycling. 
         [0006]    On-site organic material processing also requires a significant investment in personnel training on system operation and associated safety hazards. Personnel costs are further increased by the need to devote a significant amount of employee time to operating and monitoring the processing equipment, as well as performing maintenance such as disassembly of components to clear blockages—activities which inherently carry additional risks of operator injury. 
         [0007]    Due to the problems inherent in attempting to process a wide variety of organic materials on-site, on-site organic material processing is rarely economically viable, and often is associated with concomitant issues, such as unpleasant odors from decaying organic material, related health concerns, and creation of undesired pest (inset and/or mammal) attraction and intrusion in either indoor or outdoor storage containers. Accordingly, virtually all processing of organic waste from restaurants, grocery stores, institutional facilities and the like is handled offsite, with only temporary on-site holding of the organic material for pick-up and transport to an off-site processing facility and/or waste disposal unit (such as a landfill, compost facility or waste water treatment plant). 
         [0008]    The present invention solves the foregoing and related problems in the prior art by providing a unique combination of components and an operating method to produce a system with several advantages, including: a lack of need for water addition to process organic materials, regardless of their source; the ability to produce a fine particle-size discharge which is readily transferred for storage, off-site transfer, recycling and/or disposal; the ability to substantially reduce the volume of the processed organic material to minimize volume-based storage, transportation hauls and disposal costs; the ability of readily simultaneously handle a large variety of organic material sizes, geometries textures and densities without the need for any machine adjustments; and the ability to operate in a self-contained, fully enclosed, autonomous manner after loading, with minimal operator training requirements and a high degree of operator safety. Further, the system may be provided with automated flow disruption self-diagnosis capabilities and the ability to attempt to self-clear clogs and equipment jams before initiating a protective self-shutdown. The system also provides for sanitary and virtually odor-free storage of the processed organic material until the material is removed for off-site handling. The system of the present invention is further capable of processing very large volumes of organic material in a short period of time (such as may be generated at food processing facilities, restaurants or grocery stores) and do so at relatively low equipment noise levels, thereby minimizing energy consumption and facility environment disturbance. 
         [0009]    The present invention combines an organic material delivery hopper, preferably with a preferred geometry which facilitates efficient feeding of the organic material, an auger unit for initial crushing and feed transport of organic materials into a further processing unit, where the auger unit has at least one “floating” end which is free to move in a direction transverse to the longitudinal axis of the auger to aid in break-down of the incoming organic material, the further processing unit comprising a solids pump and organic material reduction device, where the solids pump is preferably a positive displacement twin rotor pump which is capable of transferring both solid and liquid materials received from the floating auger into the reducing unit, and the reducing unit preferably is a macerator capable of receiving the positive pressure organic material flow from the solids pump and reducing the material at high speed and high pressure to a finely-processed flow (preferably using any moisture containing in the organic material to form a slurry) which may be sent under positive pressure to a storage facility, preferably an adjacent storage tank, for holding prior to subsequent withdrawal and further off-site processing. The location of a solids pump before a macerator, contrary to common arrangements with a pump downstream of a organic material shredding device, provides a particularly efficient and compact arrangement of components and the generation of a relatively high velocity and high pressure processed organic material stream being discharged from the macerator. 
         [0010]    An alternative embodiment provides for the organic material reduction device to be located upstream of the auger unit, such that auger unit receives an organic material stream that already has a reduced particle size, thereby reducing sudden torque loads on the auger rotating device (typically an electric motor drive) that can arise when large pieces of relatively hard material are engaged by the auger&#39;s spiral blade, as well as minimize the potential for jamming on large pieces that are not broken down by the auger blade. The organic material reduction device may be in the form of a macerator assembly, preferably with axial material reduction blades arranged in a blade-meshing manner on parallel reduction cylinders, and further preferably with the parallel reduction cylinders&#39; rotation axes being arranged parallel to the rotation axis of the auger unit so that organic material that passes through the macerator assembly is distributed relatively evenly along the axial length of the auger below. 
         [0011]    The macerator assembly&#39;s parallel reduction cylinders may be formed by stacking alternately disc-shaped macerating blades and spacers, with the parallel reduction cylinders arranged such that macerating blade tips on the macerating blades of one reduction cylinder pass between adjacent macerating blades of the other reduction cylinder, with the space between the adjacent macerating blades being determined by the axial thickness of the spacer disc located therebetween. Preferably the macerating blade tips are configured to break up any organic material deposited on the parallel reduction cylinders, and to push the reduced organic material through the blades&#39; respective gaps for discharge to the auger unit. Further preferably the parallel reduction cylinders rotate in opposite directions such that the macerating blade tips mesh with their respective gaps in the region between the cylinder so that the organic material is reduced and passed through to the auger unit in the central region of the macerator assembly. 
         [0012]    The system may scaled as desired to match the desired processing capability to the expected amount of organic material requiring disposal. For example, a system generally sufficient to handle the volume of organic material which typically is processed for disposal at a large grocery store may be provided in a single enclosure approximately 8 feet long, 3 feet wide and less than 4 feet tall, coupled with an adjacent fiber-reinforced plastic storage tank to receive the processed organic material. An embodiment having the macerator assembly with relatively compact parallel reducing cylinders located above the auger unit may be further reduced in size. Such smaller volume embodiments are particularly well suited to installations that only need to handle smaller streams of organic material, such as individual restaurants. The tank may be located inside or outside of the facility. Such a system configuration minimizes the amount of facility floor space required in the store, while also ensuring a sufficiently low lift-height for loading to minimize the potential for lifting-related injury as the operator loads the hopper. 
         [0013]    The system is also preferably designed to have a movable cover, such as a sliding top hatch, which may be opened to load in the organic material to be processed, and fitted with at least one interlock (mechanical or electrical/electronic) which prevents system operation when the movable cover is open. Similar safety interlocks may be provided for removable panels on the system enclosure provided for access to the system components for component servicing. So equipped, all that is required for safe operation of the system is for the operator to drop the organic material into the feed hopper, close the movable cover, and turn the system on to permit the imbedded controller to initiate the organic material processing. The movable cover may also be a cover hinged at one side and rotated upwards when an organic material batch is to be loaded into the system, or be a removable cover. Similarly, a movable cover may be provided on top of a hopper extension that provides additional processing of larger batches of organic material located on top above the system housing. 
         [0014]    An operating method of the present invention may include the placement of organic material in the hopper above the floating auger. The system is preferably provided with a bar or similar device in an upper region of the hopper on which large but relatively fragile materials such as watermelons may be impacted to fracture the material into large pieces which are less prone to rotate on top of the floating auger without entering the auger&#39;s flutes to be pushed into the solids pump. 
         [0015]    Following the loading of the hopper, the operator moves the cover into its closed position to enable start-up of the system. The operator selects the appropriate processing commands, which may be as simple as a “start” button, and initiates the processing of the organic material. The system primary components, the floating auger, the solids pump and the macerator are then powered to begin processing the organic material in the hopper. Preferably the hopper auger, pump and macerator components are sized such that the processing of the batch of organic material in the hopper may be accomplished in less than five minutes, minimizing energy consumption and noise generation. It is preferable that the system be configured, for example by suitable programming of an electronic controller, to shut itself down upon detection of completion of processing of the organic material loaded into the hopper (for example, by use of optical sensors detecting the absence of further processed material flow, current sensors detecting termination of load on the auger, pump and/or macerator indicative of lack of material loading, flow sensors, and the like). It is further preferable that the system be configured to operate for a limited period, such as five minutes, after which the system would shut itself down if not previously shut down upon detection of completed organic material processing. 
         [0016]    As a part of the automated processing of the organic material following hopper loading, it is preferred that the system be configured to detect flow disturbances and/or flow blockages, for example by detection of excessive current draw in an electric motor driving one of the auger, pump and/or macerator, and in response to such a flow disruption or blockage to cause at least one of (preferably all of) the auger, pump and/or macerator to reverse direction for a period of time to attempt to self-clear the flow disruption or blockage. Further, it is preferable to have the system configured to determine, following the reverse operation, whether the flow disruption or blockage has been cleared when operation in the forward processing direction is resumed. If the attempt as self-clearing has not been successful, the system may be programmed to repeat the reversal process one of more times (for example, three times) to again attempt to clear the blockage, as development of the present invention determined that many flow disturbances may be remedied with multiple attempts at self-clearing. In order to protect the system equipment and minimize power use and noise generation, after a final unsuccessful attempt at self-clearing the system may be configured to shut down the organic material processing, preferably with an accompanying signal to the operator that manual intervention and system clearing is needed. 
         [0017]    Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1   a  is an elevation view of a front side of an organic shredder in accordance with an embodiment of the present invention. 
           [0019]      FIG. 1   b  is an elevation view of a rear side of the organic shredder in  FIG. 1   a.    
           [0020]      FIG. 1   c  is an elevation view of an end side of the organic shredder in  FIG. 1   a.    
           [0021]      FIG. 2  is a schematic illustration of an organic shredder in accordance with an embodiment of the present invention. 
           [0022]      FIG. 3  is an elevation view of the rear side of the organic shredder in  FIG. 1   b  with an access panel removed to show internal component arrangements. 
           [0023]      FIGS. 4   a - 4   d  are oblique, elevation and cross-section views of various aspects of a hopper in accordance with an embodiment of the present invention. 
           [0024]      FIG. 5  is a partial cross-section elevation view of another embodiment of the an organic shredder in accordance with the present invention. 
           [0025]      FIG. 6  is a partial cross-section elevation view of the  FIG. 5  organic shredder viewed from another side. 
           [0026]      FIGS. 7   a - 7   h  are oblique views of a macerator assembly and components thereof in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]      FIGS. 1   a - 1   c  are illustrations of an embodiment of an integrated organic shredder apparatus  1 . Essentially all of the mechanical and electronic components of the integrated organic shredder apparatus  1  are contained within an enclosure  2 . In this embodiment the enclosure  2  is approximately 8 feet long, 3.5 feet high, and 3 feet deep. 
         [0028]      FIG. 1   a  shows a front elevation view of the enclosure  2 . In this embodiment a hopper cover  3  on the top of the enclosure  2  in a manner which permits the cover  3  to be moved laterally to permit loading of the hopper and be closed during system operation. For operator safety reasons, the enclosure may be equipped with at least one safety interlock switch (such switches being well known in the art and thus not illustrated here) which precludes and/or disables system operation when the hopper cover  3  is not in the fully closed position. The front panel of the enclosure  2  include a mechanical access panel  4 , also preferably equipped with at least one safety interlock switch to preclude and/or disable system operation. In this embodiment the front panel also includes an electrical panel  5  containing simple operator controls, such as system status lights  6 , system operating switch  7  and emergency stop button  8 . The electrical panel  5  may also be opened to permit access to the system control electronics and associated electrical component wiring which are co-located in an electrical compartment behind the panel  6  for convenience in service and system diagnostics. Preferably the panels are secured with a key lock system to preclude unauthorized entry. 
         [0029]      FIG. 1   b  shows a rear elevation view of the enclosure  2 , with access panel  9  being provided to readily access the mechanical components of the system, as shown in  FIG. 3  and described further, below.  FIG. 1   c  shows and end elevation view of the enclosure  2 , with output piping flange  10  through which the processed organic material is discharged from the enclosure  2 , and the electrical power input conduit connection point  11 . 
         [0030]      FIG. 2  is a schematic illustration of the components of the organic shredder apparatus. Organic material is deposited into hopper  21  for processing. Preferably a breaker bar  22  is provided near the top of the hopper  21  to provide a stress-concentrating point of impact for initial breaking of large organic material, such as watermelons, into irregularly-shaped pieces which are more easily fed through the system. 
         [0031]    As the organic material reaches the bottom of the hopper  21 , it encounters a rotating auger  23 , preferably arranged at an angle relative to the horizontal (on the order of 10-20 degrees) to aid in the auger&#39;s self-clearing at the end of processing a load of organic material. The auger&#39;s flutes are arranged to both perform initial break-up of the organic material being deposited into the hopper  21  and to push the organic material toward the outlet of the hopper. 
         [0032]    In this embodiment the auger is a floating auger, having a first gearbox end  24  coupled to an auger drive  25 , and a floating end  26  which is free to move radially within the hopper  21  and/or the entrance of a pipe  27  leading to a solids pump  29 . By allowing the floating end  26  to move radially, the auger is able to more readily and efficiently perform initial break-up of large pieces of organic material and thereby avoid jamming. This improved performance is enabled by the auger&#39;s being able to: (i) move laterally to allow large organic material pieces to be drawn into the trough alongside the auger, and (ii) move upward in the circumferential direction to rise up over the organic material as the material moves under the auger. In the course of this floating auger movement, the large pieces of organic material are trapped under the auger and broken into smaller pieces. To further aid the auger in moving organic material toward the hopper outlet, an angled shelf  28  may be provided in the vicinity of the hopper output to form a pinch region to help guide the organic material above the auger down into the auger flutes. 
         [0033]    The auger is arranged to feed an essentially constant flow of organic material through the hopper outlet into a downstream section of pipe  27  leading to a solids pump  29  capable of moving solids in large volume and at elevated pressure, regardless of the extent of the presence or absence of liquid in the material. An example of a suitable solids pump is a Model FL 776 rotary lobe pump manufactured by Börger GmbH, Borken-Weseke, Germany. The pump is preferably readily reversible by electronic control of the pump&#39;s drive motor. 
         [0034]    The outlet of the solids pump  29  is preferably to another section of pipe  27  or directly to a downstream macerator unit  30 . An example of a suitable macerator pump is a Model HFL Multicrusher macerator manufactured by Börger GmbH, Borken-Weseke, Germany. The macerator  30  is preferably equipped with at least two rotating shafts holding multiple counter-rotating circular blades capable of shredding organic material at high speed to produce an output slurry containing organic material with a particle size on the order of ⅛″ or less. The macerator  30  is also preferably readily reversible by electronic control of the macerator&#39;s drive motor, and functions without regard to the amount of liquid in the organic material. 
         [0035]    The finely shredded organic material is discharged from the macerator  30  to a pipe  31  (in this embodiment, a four inch diameter pipe) and directed to an organics storage tank  32 . The storage tank  32  is preferably located outside of the building in which the enclosure  2  is located, with the pipe  31  passing through the building wall  33 . Due to the processing through the auger, the solids pump and the macerator, the volume of the organic material originally deposited in the hopper  21  will have gone through an order of magnitude reduction in volume. This permits processing substantial amounts of organic material in a relatively small volume, and thereby permits extended storage times before the volume of processed material must be periodically removed from the facility. When removed from the storage tank  32 , the stored organic material may be moved to a facility for further processing or directly disposed of, for example by distribution as fertilizing material or by transfer to a waste management facility. If the material is not to be reused, the substantial volume reduction during the processing will greatly reduce volume-based waste disposal charges. 
         [0036]    As part of the controller&#39;s programming to control the auger, the solids pump and the macerator, it is preferred that the controller is programmed to control the individual components&#39; operating speeds to suit the components&#39; reduction gearing ratios, both to facilitate matching the organic material mass and/or volume flow rates to the feed requirements of the components, and to assist in obtaining a desired particle size output from each component. 
         [0037]      FIG. 3  illustrates the arrangement of components within enclosure  2  corresponding to the  FIG. 2  schematic illustration, with hopper  21  located directly beneath hopper cover  3  with the incorporated auger drive  25  supported thereon. The outlet of the hopper  21  is connected to a pipe connecting the hopper  21  to the solids pump  29  (the pipe is located in this view behind the electric motor  34  driving the gearbox  35  of the solids pump  29 ). The macerator  30  is connected to the outlet of the solids pump  29  and is similarly driven by and electric motor  36  and gearbox  37 . The discharge from the organic shredder enclosure  2  passes from the macerator  30  through discharge pipe  38  and outlet flange  10 . Electrical component box  39 , located behind electric panel  5 , contains the system control electronics and electrical components such as switches, lights, relays and wiring busses. As with the solids pump  29  and the macerator  30 , in this embodiment the floating auger drive unit  25  includes and electric motor  40  and a gearbox  41 . 
         [0038]    The hopper  21  is preferably formed from stainless steel to minimize corrosion and ease cleaning.  FIGS. 4   a  and  4   b  show oblique views of the  FIG. 3  hopper  21 , floating auger  23  and the auger drive unit  24  as an assembled unit.  FIGS. 4   c  and  4   d  show an elevation cross-sectional view and an elevation end view, respectively, of the hopper itself. As shown in  FIG. 4   b , the floating auger  23  lays in a trough  42 , which is preferably produced from a section of pipe cut away in the region below the hopper. The trough  42  is preferably provided with a replaceable high density plastic liner  43  (in this embodiment, semi-circular in cross-section) to facilitate flow of organic material along the auger flow path toward the solids pump, and to protect the floating auger&#39;s flutes  44  and the trough  42  from mutual damage during operation. 
         [0039]    The hopper  21  is also provided with several features which assist in improving organic material flow through the hopper to the solids pump. As shown in  FIGS. 4   a - 4   d , the hopper  21  is provided with a breaker bar  45  near the top of the hopper, on which an operator may drop organic materials which are too large and smooth-surfaced to be readily drawn into the floating auger, such as watermelons. By fracturing such large materials on the breaker bar  45  before they fall to the bottom of the hopper  21 , the floating auger may more easily grip and/or break apart the material. The breaker bar thus aids in minimizing the extent of operator intervention which might be required to manually remove and/or break up material which would otherwise self-suspend itself on top of the auger flutes. 
         [0040]    Other feed-enhancing features of the hopper  21  include a side wall  46  parallel to the intake side of the floating auger  23 , which is set at an angle which promotes gravity feed and turn-over of organic materials as they approach the auger flutes  44 . Preferably the angled side wall  44  is arranged at an angle in the range of approximately 10° to 45° from vertical, and particularly preferably approximately 30° from vertical. The hopper  21  may also be provided with angled shelf  28  which is positioned to assist in forcing the volume of organic material above the floating auger  23  downward into the hopper outlet  47  as the auger flutes  44  are driving the organic material forward. Small additional directing plates  48  may also be provided to direct organic material laterally adjacent to the auger flutes  44  down into the hopper outlet. 
         [0041]    The electronic control unit  49  located within electrical box  39  is programmed to perform several functions, including: accepting and responding to operator commands; monitoring the status of safety switches (such as a hopper closure position safety switch, enclosure access panel closure safety switches and/or a storage tank level detector); controlling the supply of electrical power to the auger drive unit, the solids pump and/or the macerator; and managing automatic operation of the system components, including control of time of component operation, monitoring of components to detect jamming and/or clogging (for example, by monitoring of electric current draw by the auger, pump and/or macerator electric motors), and executing automatic reversal and processing terminating actions in response to detected operating conditions (such as: excessive electrical current draw indicating a component jam or below-minimum electric current draw indicating unloaded component operation during to an upstream clogging event; improper opening of the hopper cover or the enclosure access panels during organic material processing operation; completion of the predetermined operating program). 
         [0042]    An example operating sequence of the organic shredder in the foregoing embodiment would include sliding the hopper cover  3  to the open position, thereby signaling the electronic controller  49  that the cover is open and operation should be inhibited. The operator would next load the hopper  21  with the organic material to be processed, breaking larger materials on the breaker bar  45  as necessary, and close the hopper cover  3 . Following loading, the operator may switch on the organic material shredder with switch  7 . Once signaled to start processing, and upon completion of verification that any monitored safety switch and/or detector is in the proper condition (for example, hopper cover closure switch closed, enclosure panel closure switches closed), the electronic controller may provide electrical power to the motors of the auger, solids pump and macerator to begin reduction of the organic material. 
         [0043]    The electronic controller  49  may be programmed to follow a pre-determined processing program, such as continuous operation for a fixed maximum period, such as five minutes. Alternatively, the controller  49  may be programmed to periodically reverse flow for short period (for example, 30 seconds) at various intervals (for example, every two minutes) during the organic material processing to help ensure continued smooth flow of the organic material to the storage tank  32 . Such reversals may include reversal of all the electric motors, or selective reversal of individual motors. 
         [0044]    Reversals may also be initiated in response to an indication of clogging or jamming being detected by the controller  49 . Preferably, in order to minimize the need for operator intervention and component clearing maintenance, the electronic controller  49  may be programmed to attempt to automatically self-clear clogging or jamming upon detecting a potential clogging or jamming event. For example, the controller may respond to an indication of clogging or jamming by first reversing all of the electric motors for a short period (for example, 30 seconds), then directing power in the forward direction to the electric motors while monitoring to determined whether the indication of clogging or jamming is still present. Particularly preferable is for the controller  49  to be programmed to make at least a second attempt at self-clearing if a continued clogged or jammed condition is still present by executing another electric motor reversal operation. If the clogged or jammed condition is not cleared after a predetermined number of self-clearing attempts (for example, after three attempts), the electronic controller  49  may be programmed to automatically shut down the organic shredder and provide a signal to the operator that further operator action to clear the clog or jam is required. 
         [0045]      FIGS. 5-7   h  illustrate another embodiment of the present invention.  FIG. 5  schematically illustrates the arrangements of an organic shredder  50  without a side cover panel on the visible side of enclosure  52 , showing an arrangement of hopper  51  and optional exterior hopper extension  51   a  located over a macerating assembly  54  that receives organic material placed in hopper  51 . The exterior hopper  51   a  is provided with a movable hopper cover  51   b . If the exterior hopper is not present, the movable cover  51   b  may be located directly over the hopper  51 . The macerator assembly  54  located beneath the hopper  51  is located above an auger unit  53  that receives the reduced-size organic material pieces released from the macerator assembly  54 . An auger drive unit  55  is coupled to the auger unit to drive rotation of the auger (not shown) within the auger unit in a manner similar to the foregoing embodiment. At the opposite end of the auger unit the reduced organic material is discharged via piping  57  coupled to a solids pump  59 . The solids pump  59  pumps the reduced solid organic material from the organic shredder  50  though an outlet  59   a  to an exterior receiving tank (not shown). In this embodiment, the solids pump  59  and the macerator assembly  54  are driven by an electric motor drive unit  56 , in the case of the macerator assembly  54  via reduction gearing  54   a  that provides synchronized counter-rotation of the parallel reducing cylinders therein. The drive units may include, as here, a combined drive unit, or separate drive units may be provided for each of the macerator assembly, auger unit and solids pump. 
         [0046]      FIG. 6  schematically illustrates an elevation view from another side of the organic shredder  50  in which the solids pump and drive unit for the solids pump and macerator assembly is omitted for clarity. As in  FIG. 5 , the hopper  51 , external hopper  51   a  and hopper cover  51   b  are located above the macerator assembly  54 , with the auger unit  53  located beneath the macerator assembly to receive the reduced-size organic material. Visible through piping  57  is a discharge end of the auger  53   a , and partially visible behind the auger unit  53  is its drive unit  55 . In addition, this view includes an organic shredder electrical control component housing  58   a  in which the organic shredder  50 &#39;s control electronics and other electrical components (not shown) are located. This view also shows a user control panel housing  58   b  that faces outward at the face of a side cover of housing  52  to position the run/stop/etc. controls at a location convenient to the operator and thereby eliminate any need for the operator to open the side panels of enclosure  52  during normal operations. Electrical housings  58   a ,  58   b  are omitted from  FIG. 5  for clarity. 
         [0047]      FIG. 6  also shows an end view of macerator assembly drive gears  54   a  that are coupled to the drive unit  56  (not shown for clarity). In this embodiment, the gears  54   a  mesh directly with one another to synchronize the rotation of the parallel reducing cylinders, with only one of the gears  54   a  being driven by the drive unit  56 . 
         [0048]    The macerator assembly in the  FIGS. 5-6  embodiment is shown in greater detail in  FIGS. 7   a - 7   h . The macerator assembly  54  includes two parallel reducing cylinders  54   b  having central shafts  54   c . The reducing cylinder assemblies  54   b  are formed by stacking a series of, in this embodiment, two types of discs on shafts  54   c .  FIGS. 7   a  and  7   b  are oblique views of a macerating blade disc  54   d  and a spacer disc  54   h , respectively. The macerating blade disc  54   d  includes a blade portion  54   e  extending radially above a base outer radius of the blade disc. The blade portion  54   e  is shaped with a leading edge  54   f  that is configured to shear material it encounters when the reducing cylinder assembly is rotating, and a trailing edge  54   g  configured to smoothly return the shape of the blade portion  54   e  to the base outer radius of the blade disc in a manner that minimizes organic material accumulation on the trailing side of the blade portion. In this embodiment the macerating blade disc  54   d  has only one blade portion  54   e , however, a plurality of blade portions may be present on a blade disc. For example, blade portions may be located on opposite sides of the macerating blade disc. 
         [0049]    The spacer disc  54  has an outer radius that is smaller than the outer radius of the macerating disc  54   d . The outer radius of the spacer disc  54   h  must be smaller than the outer radius the macerating disc  54   d  by an amount that would permit the blade portion  54   e  of a macerating blade disc  54   d  on the adjacent reducing cylinder to not contact the spacer disc when the parallel reducing cylinder are rotating. The clearance between the outer radius of the spacer disc  54   h  and macerating blade portion  54   e , as well as the axial thickness of the spacer disc  54   h , may be varied to provide radial and axial clearances between the blade discs  54   h  and macerating blade discs  54   d  that provide optimal organic material size reduction while also avoiding clogging and/or stalling of the reducing cylinders  54   b  as organic material accumulated in the region between parallel reducing cylinders. Preferably the parallel reducing cylinders are driven in counter-rotating directions, and further preferably the counter-rotating directions are such that the organic material received from the hopper is macerated in the region between the rotating parallel reducing cylinders.  FIGS. 7   c - 7   d  show examples of how the macerating blade discs and spacer discs may be “stacked” to provide gaps between blade discs and provide groups of bladed discs. 
         [0050]      FIG. 7   e  shows an oblique view of a subassembly of macerator assembly  54 , in which the parallel reducing cylinders  54   b  are arranged adjacent to, and meshing with, one another, with the macerator blade discs  54   d  of one of the reducing cylinders  54   b  being aligned with adjacent spacing discs  54   h  of the other of the reducing cylinders. In this embodiment the blade portions  54   e  are grouped in groups of three adjacent blades portions, with the three-blade groups being staggered circumferentially around the reducing cylinders  54   b  to enhance smooth processing of the organic material through the macerator assembly  54 . The present invention is not restricted to this specific arrangement, as macerating blade discs and spare discs may be positioned directly adjacent to the same type of disc to form one or more larger organic material blade sections, as long as the so-grouped discs (either  54   d  or  54   h ) are aligned with the same number of directly adjacent discs of the other disc type (either  54   h  or  54   d ) on the adjacent reducing cylinder  54   b.    
         [0051]      FIG. 7   e  also shows the parallel reducing cylinders being located and aligned by end plates  54   j , with drive gears  54   a  on the ends of their respective shafts  54   c  being located axially outside the adjacent end plate  54   j . In this embodiment, rather than the gears  54   a  being sided to mesh with one another and driving of a single gear, the gears are configured to be driven by a chain (not shown) coupled to the macerator assembly drive unit. 
         [0052]      FIG. 7   f  shows the  FIG. 7   e  macerator sub-assembly enclosed by side plates  54   k  in a manner that forms a complete macerator housing having bolting flanges configured to be mated to the hopper  51  on an upper flange surface and to the auger unit  53  on a lower flange surface. 
         [0053]      FIGS. 7   g - 7   h  show an organic material cleaning insert basket  54   m  in place within the macerator assembly  54  and on by itself, respectively. This cleaning insert basket  54   m  is arranged to support a plurality of cleaning tynes  54   n  extending radially inward in the gaps between the macerating blade discs  54   d  from the periphery of the macerator assembly, in the region of the side plates  54   k . The tynes  54   n  are positioned to remove organic material that passes through the region between the parallel reducing cylinders but does not fall into the auger unit  53  from the sides and radially outer edges of the macerator and spacer discs. As shown in  FIG. 7   h , the cleaning insert basket  54   m  may be formed as a one-piece assembly that may be lowered into position from above and easily removed in the same manner during servicing of the macerator assembly  54 . Other blade-cleaning arrangements are possible as long as the arrangement deflects a substantial portion of any organic material remaining on the reducing cylinders off of the discs. For example, a comb-like bar made from a material such as nylon cold be located directly to the macerator housing with its comb tynes extending from the housing wall into the gaps between the macerating blade discs. Preferably, such a comb bar arrangement would be positioned at or below the level of the reducing cylinder shafts. This positioning facilitates the falling of the organic material being continuously removed from the reducing cylinders into the auger unit without significant interference from the organic material on the cylinders that continues to reach the comb as the reducing cylinders rotate. 
         [0054]    The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Because such modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof