Abstract:
A warewasher includes a scrap reducing arrangement located within a wash zone for capturing scrap debris falling downward toward a tank. The scrap reducing arrangement is configured to automatically deliver captured scrap debris away from the tank when liquid spraying within the wash zone ceases.

Description:
TECHNICAL FIELD 
       [0001]    This application relates generally to warewasher systems which are used in commercial applications such as cafeterias and restaurants and, more particularly, to an automated scrapping system useful in removing debris from a wash zone in such a warewasher. 
       BACKGROUND 
       [0002]    Commercial warewashers commonly include a housing area which defines washing and rinsing zones for dishes, pots pans and other wares. In the pre-wash, wash and post-wash zones of pass through or continuous-type machines, water is typically pumped from a tank through a pump intake, delivered to the wares via a spraying operation and collected in the tank for re-use. A similar recirculation system is used in batch-type machines as well. In either case, food debris from the ware commonly falls down into the tank, and can build up to undesired levels in the tank. Other types of scrap may also fall into the tank. Debris catching baskets have been incorporated into the tanks in order to reduce the scrap debris level within the tanks, but with previous baskets arrangements the entire machine must be shut down in order to enable manual removal and emptying of the basket. 
         [0003]    It would be desirable to provide a an arrangement that automatically removes scrap debris. 
       SUMMARY 
       [0004]    A scrap reducing arrangement may configured to automatically deliver the captured food debris or other scrap debris or material (napkins, straws etc.) away from the tank when liquid spraying within the wash zone ceases. 
         [0005]    In one aspect, a warewasher for washing wares includes a chamber for receiving wares, the chamber having at least one wash zone that includes a tank for collecting sprayed liquid of the wash zone and a liquid recirculation system for moving liquid from the tank to a spray arrangement of the wash zone. A scrap reducing arrangement is located within the wash zone for capturing scrap debris falling downward toward the tank. The scrap reducing arrangement is configured to automatically deliver captured scrap debris away from the tank when liquid spraying within the wash zone ceases. 
         [0006]    In one implementation, the warewasher is a continuous-type warewasher wherein the wash zone is located upstream of a final rinse zone, and the warewasher includes a conveyor for moving wares in a conveyance direction through the chamber from the wash zone to the final rinse zone. 
         [0007]    In one implementation, when liquid spraying in the wash zone ceases, water conditions in the wash zone cause a flushing of captured scrap debris along a purge flow passage away from the tank. 
         [0008]    In one implementation, the scrap reducing arrangement includes a scrap collecting volume in the wash zone and a purge flow passage extending from the scrap collecting volume away from the wash zone. When liquid spraying within the wash zone ceases, water in suspension returns to the tank causing an increase in a water level of the tank to create a head pressure in the scrap collecting volume that causes a flushing operation from the scrap collecting volume along the purge flow passage. 
         [0009]    In one implementation, the purge flow passage leads to a compartment external of the wash zone. The compartment including a strainer to capture flushed scrap debris and a drain outlet to permit flushed liquid to be drained. 
         [0010]    In one implementation, the scrap collecting volume includes a flush outlet from which the purge flow passage extends. At least a portion of the purge flow passage extends upward so that part of the purge flow passage is higher than the flush outlet. 
         [0011]    In one implementation, the scrap reducing arrangement includes: a scrap collecting bucket to which scrap debris is directed by water flows falling down into the tank, the scrap collecting bucket including a screening portion in fluid communication with the tank. A flow passage extends from a lower part of the scrap collecting bucket away from the tank, the flow passage configured such that (i) during liquid recirculation and spraying within the wash zone a water level in the tank is below a level that forces captured scrap debris along the flow passage and (ii) upon cessation of liquid recirculation and spraying within the wash zone the water level in the tank rises to a level that creates a head pressure to force capturing scrap debris and water to move along the flow passage. 
         [0012]    In one implementation, the flow passage is configured such that upon cessation of liquid recirculation and spraying within the wash zone the water level in the tank rises to a level that causes a flushing operation along the flow passage. 
         [0013]    In one implementation, the flow passage extends to a scrap collecting container. The scrap collecting container traps scrap debris but allows liquid to move to a drain path. The scrap collecting container includes a removable strainer. 
         [0014]    In one implementation, a controller is configured to at least temporarily stop liquid recirculation and spraying in the wash zone based upon one or more of (i) a timed basis and/or (ii) detection of the absence of wares in the chamber and/or (iii) detection of debris within the scrap collecting bucket. 
         [0015]    In another aspect, a warewasher for washing wares includes a chamber for receiving wares, the chamber includes a tank for collecting sprayed liquid of the wash zone and a liquid recirculation system for moving liquid from the tank to a spray arrangement of the wash zone. A scrap reducing arrangement is located within the wash zone for capturing scrap debris falling down toward the tank. The scrap reducing arrangement includes a scrap collecting volume positioned in the tank and into which falling scrap debris is directed. The scrap collecting volume includes an outlet opening, with a purge flow passage extending from the outlet opening to a location external of the wash zone. At least a portion of the purge flow passage extends upward so that a part of the purge flow passage is higher than the outlet opening. 
         [0016]    In one implementation, the outlet opening is located below a normal water level of the tank that exists during liquid recirculation and spraying in the wash zone, and the part of the purge flow passage is higher than the normal water level. 
         [0017]    In a further aspect, a method of capturing and purging scrap debris from a wash zone of a warewasher involves: recirculating a wash liquid from a tank of the wash zone to spray nozzles of the wash zone so as to spray the wash liquid toward wares in the wash zone; directing scrap debris falling from wares toward and into a scrap collecting volume within the tank, the scrap collecting volume including at least some screening material to remain in fluid communication with the tank, the scrap collecting volume including a scrap purge flow passage; at least temporarily stopping the recirculating of wash liquid, causing water conditions in the wash zone to change so as to move scrap debris in the scrap collecting volume along the scrap purge flow passage. 
         [0018]    In one implementation of the method, upon stopping the recirculating of wash liquid a water level in the tank rises to a level that creates a head pressure to force scrap debris in the scrap collecting volume and water to move along the scrap purge flow passage. 
         [0019]    In one implementation of the method, the directing step utilizes upper screening material configured to catch and direct scrap debris toward an upper opening of the scrap collecting volume. 
         [0020]    In one implementation of the method, the scrap purge flow passage is configured such that upon stopping the recirculation of wash liquid the water level in the tank rises to a level that causes a flushing operation along the scrap purge flow passage, including a temporary siphon flow along the scrap purge flow passage until the water level in the tank drops to a level that breaks the siphon. 
         [0021]    In one implementation of the method, the scrap purge flow passage includes an upwardly directed portion and extends to a scrap collecting container external of the wash zone. 
         [0022]    In one implementation of the method, the external scrap collecting container traps scrap debris but allows liquid to move to a drain path. 
         [0023]    In one implementation of the method, the external scrap collecting container includes a strainer that can be removed for disposal of collected scrap debris. 
         [0024]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a schematic elevation of one embodiment of a warewasher; 
           [0026]      FIG. 2  is a partial schematic view of one embodiment of a scrap reducing arrangement of the warewasher; 
           [0027]      FIG. 3  is a partial perspective view of a wash chamber including the scrap reducing arrangement; 
           [0028]      FIG. 4  is a perspective view of a scrap collecting bucket; and 
           [0029]      FIG. 5  is a perspective view of the components of the scrap reducing arrangement. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Referring to  FIG. 1 , an exemplary conveyor-type warewash system, generally designated  10 , is shown. Warewash system  10  can receive racks  12  of soiled wares  14  from an input side  16  which are moved through tunnel-like chambers from the input side toward a dryer unit  18  (optional) at an opposite end of the warewash system by a suitable conveyor mechanism  20 . Either continuously or intermittently moving conveyor mechanisms or combinations thereof may be used, depending, for example, on the style, model and size of the warewash system  10 . Flight-type conveyors in which racks are not used are also possible. In the illustrated example, the racks  12  of soiled wares  14  enter the warewash system  10  through a flexible curtain  22  into a pre-wash chamber or zone  24  where sprays of liquid from upper and lower pre-wash manifolds  26  and  28  above and below the racks, respectively, function to flush heavier soil from the wares. The liquid for this purpose comes from a tank  30  via a pump  32  and supply conduit  34 . A drain system  36  provides a single location where liquid is pumped from the tank  30  using the pump  32 . Liquid can be drained from the tank via drain path  36 , for example, for a tank cleaning operation. 
         [0031]    The racks proceed to a next curtain  38  into a main wash chamber or zone  40 , where the wares are subject to sprays of cleansing liquid from upper and lower wash manifolds  42  and  44  with spray nozzles  47  and  49 , respectively, these sprays being supplied through a supply conduit  46  by a pump  48 , which draws from a main tank  50 . A heater  58 , such as an electrical immersion heater provided with suitable thermostatic controls (not shown), maintains the temperature of the cleansing liquid in the tank  50  at a suitable level. Not shown, but which may be included, is a device for adding a cleansing detergent to the liquid in tank  50 . During normal operation, pumps  32  and  48  are continuously driven, usually by separate motors, once the warewash system  10  is started for a period of time. 
         [0032]    The warewash system  10  may optionally include a power rinse (also known as post-wash) chamber or zone (not shown) that is substantially identical to main wash chamber  40 . In such an instance, racks of wares proceed from the wash chamber  40  into the power rinse chamber, within which heated rinse water is sprayed onto the wares from upper and lower manifolds. 
         [0033]    The racks  12  of wares  14  exit the main wash chamber  40  through a curtain  52  into a final rinse chamber or zone  54 . The final rinse chamber  54  is provided with upper and lower spray heads  56 ,  57  that are supplied with a flow of fresh hot water via pipe  60  under the control of solenoid valve  62 . A rack detector  64  is actuated when rack  12  of wares  14  is positioned in the final rinse chamber  54  and through suitable electrical controls, the detector causes actuation of the solenoid valve  62  to open and admit the hot rinse water to the spray heads  56 ,  57 . The water then drains from the wares into tank  50 . The rinsed rack  12  of wares  14  then exits the final rinse chamber  54  through curtain  66 , moving into dryer unit  18 . 
         [0034]    As suggested in  FIG. 1 , the warewasher includes a scrap reducing arrangement  100  associated with wash zone  24  and tank  30 . Although the scrap reducing arrangement is contemplated primarily for use in the pre-wash zone as shown, it could be incorporated into the main wash zone of a machine as well, or in other zones of the machine if desired. 
         [0035]    Referring now to  FIGS. 2-5 , an exemplary implementation of the scrap reducing arrangement  100  is shown. The scrap reducing arrangement  100  includes a scrap collecting volume  80  to which food and other scrap debris is directed by water flows falling down into the tank  30  (e.g., per arrows  82 ). A surrounding pan  102  with or without some strainer portions may be used for this purpose (e.g., capturing debris while letting water enter the tank, and enabling the debris to flow to an upper opening  104  of the scrap collecting volume  80 ). The scrap collecting volume  80  may be defined by a scrap collecting bucket  80   a,  where an upper portion  84  of the scrap collecting bucket includes sides formed of a screening material that enables fluid communication between the volume  80  and the tank  30 , permitting water to move from the volume  80  to the tank. A lower portion  86  of the bucket includes solid walls, as that is where the food and other scrap debris primarily collects. 
         [0036]    The bucket  80   a  includes an outlet opening  106  in lower portion  86 , and the outlet opening  106  aligns with an opening  108  in the sidewall of the tank  30 . A purge flow passage  88  (e.g., formed in part by pipe/tube  88   a ) extends from the opening  106  of the scrap collecting bucket to a location away from the tank and out of the wash zone. In this case the tube  88   a  extends to a location external of the primary housing  110  of the warewash machine to a scrap collecting container  90  external of the chamber within the housing. The external scrap collecting container  90  traps food debris but allows liquid to move to a drain path (e.g., via drain tube  92 ). The external scrap collecting container  90  may include a removable strainer  94 , such that personnel may occasionally remove the strainer and empty collected food debris into the garbage or other disposal unit. Notably, this can be done without shutting down the warewash machine. 
         [0037]    The purge flow passage  88  from the scrap collecting volume  80  is configured such that during liquid recirculation and spraying within the wash zone a normal operating water level  112  in the tank  30  is below a level that forces collected food debris along the flow passage  88 . Specifically, at least a portion of the purge flow passage extends upward as shown so that part (e.g., part  88   b ) of the purge flow passage is higher than both the outlet opening  106  and the normal operating level  112 . However, upon cessation of liquid recirculation and spraying within the wash zone, falling liquid in suspension (e.g., which may be on the order of 3-6 gallons or more) not only pushes debris on the pan  102  into the opening  104 , but also causes the water level in the tank  30  to rise to a higher level that creates a sufficient head pressure to force collected food and other scrap debris and water to move along the flow passage  88 . Specifically, the water level in the tank rises to a level  114  that is higher than the highest flow passage part  88   b.  Thus, the water level in the tank rises to a level that causes a flushing operation to occur along the purge flow passage  88 . 
         [0038]    In some embodiments the flushing operation may produce a temporary siphon effect (e.g., suction cause by a falling liquid column at the far end of the tube  88   a ) along the purge flow passage  88 . In other embodiments, it is simply the large rush of the suspended water into the scrap collecting that flushes the debris along the passage until the water level within the scrap collecting volume falls below the highest flow passage part  88   b,  with little or no siphon effect being created. 
         [0039]    When recirculation in the wash zone begins again, the tank water level will again fall to and remain at a level below that which causes flushing. Replenishing of the water level in the wash tank may be achieved by flows of final rinse water that are directed to the wash tank after spraying and/or by a separate replenish path. 
         [0040]    Various techniques may be used to initiate the flushing operation. For example, a controller may be configured to at least temporarily stop liquid recirculation and spraying in the wash zone based upon one or more of (i) a timed basis (e.g., every 3-10 minutes) and/or (ii) detection of the absence of wares in the chamber (e.g., based upon one or more rack detectors of the machine) and/or (iii) detection of debris within the scrap collecting bucket. 
         [0041]    It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. Accordingly, other embodiments are contemplated and modifications and changes could be made without departing from the scope of this application. For example, although a conveyor-type machine is shown in  FIG. 1 , the scrap reducing arrangement could be implemented on other machines. Warewash machines are categorized into two types based on the operating modes (i.e., batch or continuous) and this concept is applicable to both machine types. In the case of batch-type machines, the wash chamber of the machine forms the wash zone and the sump at the bottom of the wash chamber forms the tank where the scrap reducing arrangement would be located.