Abstract:
A warewash machine carries out at least one of (i) delivering both compressed air and rinse liquid to a plurality of wash spray nozzles of the warewash machine for spraying onto the wares during at least part of a washing operation of a ware cleaning cycle, wherein the wash liquid is recirculated from a wash tank below the spray zone; or (ii) lowering wares from the spray zone into a wash tank below the spray zone to submerge the wares within wash liquid of the wash tank and delivering compressed air into the wash tank during at least part of a washing operation of a ware cleaning cycle; or (iii) delivering both compressed air and rinse liquid to a plurality of rinse spray nozzles of the warewash machine for spraying onto the wares during at least part of a rinsing operation of a ware cleaning cycle.

Description:
TECHNICAL FIELD 
       [0001]    This application relates generally to warewashers such as those used in commercial applications such as cafeterias and restaurants and, more particularly, to systems and methods to utilize air for ware cleaning in such warewashers. 
       BACKGROUND 
       [0002]    Commercial warewashers commonly include a housing which defines one or more internal washing and rinsing zones for dishes, pots pans and other wares. In conveyor-type machines wares are moved through multiple different spray zones within the housing for cleaning (e.g., pre-wash, wash, post-wash (aka power rinse) and a rinse zone or zones). One or more of the zones include a tank in which liquid to be sprayed on wares is heated in order to achieve desired cleaning. In batch-type machines wares are typically manually moved into a generally stationary location within a chamber for cleaning, and then manually removed from the machine upon completion of all operations/steps of the cleaning cycle. 
         [0003]    Reduced water consumption is becoming more important in certain areas in view of the growing demands for water as well as an increase in the number of drought stricken areas. 
         [0004]    It would be desirable to provide a warewasher system and method that reduces water consumption. 
       SUMMARY 
       [0005]    In one aspect, a warewash machine for cleaning wares includes a chamber for receiving wares, the chamber having at least one spray zone. A rinse system associated with the spray zone includes one or more spray nozzles and a feed system connected to the spray nozzles. The feed system includes both a rinse liquid line and a compressed air line. 
         [0006]    In one implementation of the foregoing aspect, the feed system is operable to feed a combination of the rinse liquid and the compressed air to the spray nozzles during at least part of a rinsing operation carried during a ware cleaning cycle. 
         [0007]    In one instance of the foregoing implementation, a ratio of rinse liquid flow to compressed air flow that is fed to the spray nozzles is variable by adjustment of one or more flow control devices. 
         [0008]    In another implementation of the foregoing aspect, the feed system includes a first flow control device for selectively controlling flow of rinse liquid from the rinse liquid line to the spray nozzles and a second flow control device for selectively controlling flow of compressed air from the compressed air line to the spray nozzles. A controller is operatively connected to control both the first flow control device and the second flow control device. The controller is configured to control the first flow control device and the second flow control device so as to feed a combination of the rinse liquid and the compressed air to the spray nozzles during at least part of a rinsing operation of a ware cleaning cycle. 
         [0009]    In one instance of the immediately preceding implementation, the first flow control device comprises a first valve and the second flow control device comprises a second valve. 
         [0010]    In another instance of the immediately preceding implementation, the controller is configured to control the first flow control device and the second flow control device to feed only compressed air to the spray nozzles during a ware drying step of the ware cleaning cycle. Alternatively, or in addition, the controller is configured to control the first flow control device and the second flow control device to feed only rinse liquid to the spray nozzles during at least part of the rinsing operation. 
         [0011]    In another implementation of the foregoing aspect, the chamber includes a wash tank below the spray zone, and a mechanism from moving wares from the spray zone down into the wash tank for a washing operation and back up to the spray zone for a rinsing operation. In such a case, the wash tank holds wash liquid in which the wares are submerged during the washing operation, and the compressed air line is selectively connectable to delivered compressed air into the wash liquid during at least part of the washing operation. 
         [0012]    In another implementation of the foregoing aspect, the chamber includes a wash tank and an associated recirculation system for recirculating wash liquid from the wash tank for spraying the wash liquid in the spray zone onto wares during a washing operation. The compressed air line is selectively connectable to the recirculation system for delivering a combined spray of wash liquid and compressed air onto the wares during the washing operation. 
         [0013]    In another aspect, a warewash machine for cleaning wares includes a chamber for receiving wares, the chamber having at least one spray zone, wherein the chamber includes a wash tank below the spray zone and at least one of: (i) a mechanism from moving wares from the spray zone down into the wash tank for a washing operation and back up to the spray zone for a rinsing operation, wherein the wash tank holds wash liquid in which the wares are submerged during the washing operation, and a compressed air line is connected to deliver compressed air into the wash liquid during at least part of the washing operation, or (ii) a recirculation system for recirculating wash liquid from the wash tank to spray nozzles of the spray zone for spraying the wash liquid onto wares during a washing operation, and a compressed air line is connected to the recirculation system to deliver a combined spray of wash liquid and compressed air from the spray nozzles onto the wares during the washing operation. 
         [0014]    In implementations of the immediately preceding aspect, in the case of either (i) or (ii), the compressed air line is selectively connectable to one or more rinse spray nozzles of the warewash machine such that a combined spray of rinse liquid and compressed air is delivered to the rinse spray nozzles during at least part of a rinsing operation of a ware cleaning cycle. 
         [0015]    In a further aspect, a method is provided for cleaning wares in a warewash machine that includes a chamber for receiving wares, the chamber having at least one spray zone. The method involves carrying out at least one of the following steps: (i) delivering both compressed air and rinse liquid to a plurality of wash spray nozzles of the warewash machine and spraying a combination of the compressed air and the wash liquid from the rinse spray nozzle onto the wares during at least part of a washing operation of a ware cleaning cycle, wherein the wash liquid is recirculated from a wash tank below the spray zone; or (ii) lowering wares from the spray zone into a wash tank below the spray zone to submerged the wares within wash liquid of the wash tank and delivering compressed air into the wash tank during at least part of a washing operation of a ware cleaning cycle, and thereafter raising the wares back up into the spray zone for a rinsing operation; or (iii) delivering both compressed air and rinse liquid to a plurality of rinse spray nozzles of the warewash machine and spraying a combination of the compressed air and the rinse liquid from the rinse spray nozzle onto the wares during at least part of a rinsing operation of a ware cleaning cycle. 
         [0016]    In one implementation of the immediately preceding aspect, both steps (i) and (iii) are carried out during a common ware cleaning cycle. 
         [0017]    In another implementation of the immediately preceding aspect, both steps (ii) and (iii) are carried out during a common ware cleaning cycle. 
         [0018]    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 
         [0019]      FIG. 1  is a schematic side elevation of one embodiment of a warewasher; and 
           [0020]      FIG. 2  is a flow chart of exemplary process/logic for the warewasher of  FIG. 1 ; 
           [0021]      FIG. 3  is a schematic side elevation of another embodiment of a warewasher; and 
           [0022]      FIG. 4  is a flow chart of exemplary process/logic for the warewasher of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    Referring to  FIG. 1 , an exemplary warewash machine  10  is shown, with a housing  12  and an internal chamber  14  with a spray zone  20  that can receive a rack  16  (or racks) of soiled wares  18  for cleaning (e.g., through an access opening closeable by a door or hood or, in some cases, through an access opening without a door). The machine includes a wash tank  22  below the spray zone. A mechanism  24  for lowering wares from the spray zone  20  down into the wash tank  22 , and raising the wares from the wash tank  22  back up into the spray zone  20  is shown schematically. By way of example, the mechanism  24  could be a lift platform (e.g., open wire frame type) that is raised or lowered by way of a motor and belt or chain drive, or by way of one or more linear actuators. However, other mechanism configurations are possible. 
         [0024]    The spray zone  20  includes one or more rinse arms  26  (stationary and/or moving depending upon machine type) with associated spray nozzles  28  for spraying rinse liquid onto wares when the wares are up in the spray zone  20 . A feed system  30  feeds to the spray arms  26  and includes a rinse liquid line  32  and a compressed air line  34 , each of which is connected, or selectively connectable, by a respective valve  36  and  38  to the rinse arm input path  40 . The rinse liquid could, for example, come from a hot water booster and may or may not include a rinse agent. The compressed air could come from an external source as a standalone unit, from the facility utility or from a compressor installed on the machine. The compressed air line  34  is also connected, or selectively connectable, to the wash tank  22  by a valve  42  and feed path  44 , where the feed path  44  includes multiple inputs to the wash tank  22 . A controller  50  is operatively connected to each of the valves  36 ,  38 ,  42 , the mechanism  24 , an air sensor  46  (e.g., temperature and/or humidity and/or other air quality characteristics) and an air heater  48  (e.g., an electric heater). As used herein, the term controller is intended to broadly encompass any circuit (e.g., solid state, application specific integrated circuit (ASIC), an electronic circuit, a combinational logic circuit, a field programmable gate array (FPGA)), processor(s) (e.g., shared, dedicated, or group—including hardware or software that executes code), software, firmware and/or other components, or a combination of some or all of the above, that carries out the control functions of the machine or the control functions of any component thereof. 
         [0025]    Referring to the schematic machine  10  of  FIG. 1  and the process flow diagram  60  of  FIG. 2 , in an automatic mode, the wash tank  22  is filled with the required volume of wash liquid (e.g., water with detergent either predosed or dosed at the beginning of a cleaning cycle). The valves  36 ,  38  and  42  are all closed at this time. Per step  62 , the machine  10  receives rack(s) in the upper position in the spray zone per dashed line form of rack  16 , and a door of machine is closed at step  64  to activate a switch/sensor to initiate cleaning. Alternatively, or in addition to door closure, a user interface button could be manually pressed to initiate cleaning. The rack transport/shift mechanism  24  then operates to submerge the rack(s) into the wash tank water per solid line form of rack  16 ′. When the rack is moved to submerged position (e.g., as determined by an activated switch or sensor of the mechanism  24 ) per step  66 , the controller  50  initiates the wash operation of the cleaning cycle at step  68 , which includes opening valve  42  to deliver compressed air from line  34  into the washing liquid for washing for a predetermined time (while valves  36  and  38  remain closed). The compressed air may be introduced directly into the volume of water in which the wares are submerged as suggested, and may be introduced during the entire washing operation of the cleaning cycle or during only part of the washing operation. The introduction of the compressed air aids in cleaning by creating turbulent conditions in the washing tank. 
         [0026]    At the end of the washing operation of the cycle (e.g., after a set time period or after a sensor indicates sufficient washing) per step  70 , the rack transport/shift mechanism  24  moves the rack back into the upper position in the spray zone  20  per step  72  for rinsing (e.g., via sprays from nozzles  28  in the one or more rinse arms  26 ). Per step  74 , for purpose of rinsing, valve  42  is closed and valves  38  and  36  are opened to deliver a combined rinse water and compressed air mixture that is directed onto the wares through the spray nozzles  28 , such as a combined flow through the same nozzle(s)  28  for rinsing for a predetermined time (e.g., which predetermined time can be set or varied). The compressed air may be introduced during the entire rinsing operation of the cleaning cycle or during only part of the rinsing operation. 
         [0027]    At the end of the rinsing operation of the cleaning cycle as determined at step  76 , the valve  42  remains closed and valve  36  is also closed such that compressed air is delivered into the ware chamber (without any water) through the spray nozzles  28  for a drying operation (e.g., for a predetermined time for a time as determined by a sensor that detects how dry the wares are) per step  78 . The heater  48  may be activated or otherwise controlled during the drying period based on air temperature and air quality factors/conditions such as humidity, moisture, etc. as indicated by the sensor(s)  46 . Moreover, the flowrate or amount of compressed air for drying may be controlled or set based upon, for example, the type of ware, shape, weight, etc. The valves  36 ,  38  and  42  (or other flow control devices) can be regulated/controlled (e.g., by the controller  50 ) to achieve various compressed air flows F 1  and F 2  and various rinse water flows F 3  to achieve different water-to-air ratios and flows (e.g., F 1  only for the wash, F 3 /F 2  for rinsing and F 2  for drying, where the level of each of F 1 , F 2  and F 3  can be controlled) as necessary for desired wash, rinse and drying of the various wares types, such as heavy or light duty loads. 
         [0028]    While the above description primarily contemplates and automated machine  10 , in a manual machine or mode of the  FIG. 1  machine manual button presses may be used for initiating rack submersion, raising the rack back into the upper position, starting the rinsing, starting the drying, etc. Moreover, the valves  36 ,  38  and  42  could be controlled manually as well. 
         [0029]    Referring to  FIG. 3 , another exemplary warewash machine  100  is shown, where similar features/components to machine  10  are shown with similar number designations. Here, compressed air line  34  is connected through a valve  102  to the rinse input path  40 , which can also form part of the wash liquid path as shown. However, it is recognized that separate wash arms  104  with wash nozzles  106  may also be provided, in which case an additional valve  108  may be provided so that separate compressed air flows to the wash path and the rinse path are possible. The wash tank  22  includes a recirculation system with pump  110 , line  112  and valve  114  which can feed to the spray nozzles  28  in one embodiment, or could feed to the spray nozzles  106  in an embodiment with separate wash arm(s)  104 . The machine may be a rack-type machine or may be a conveyor-type with a conveyance mechanism for moving wares through various spray zones of the machine. A controller  150  is operatively connected to each of the valves  36 ,  102 ,  108 ,  114 , and the pump  110 , air sensor(s)  46  and heater  48 . 
         [0030]    Referring to the schematic machine  100  of  FIG. 3  and the process flow diagram  160  of  FIG. 4 , in an automatic mode, the wash tank  22 ′ is filled with the required volume of water with detergent either predosed or dosed at the beginning of washing. The valves  36 ,  102 ,  108  and  114  are all closed at this time, and the pump  110  is off. Per step  162 , the machine  10  receives rack(s) in the chamber, and a door of machine is closed at step  164  to activate a switch/sensor to initiate cleaning. Alternatively, or in addition to door closure, a user interface button could be manually pressed to initiate cleaning per step  166 . At step  168 , the valve  114  is opened and the pump  110  is then operated to circulate the wash fluid from the tank  22 ′ up to the spray arms/nozzles  26 / 28  or  104 / 106  of the spray zone  20 , while valves  36  and  102  (and if applicable  108 ) are closed. In some cases valve  102  (or  108  if applicable) could also be opened during washing operation, or part of the washing operation, to deliver a combination of compressed air and washing liquid through the spray nozzles during the washing operation. 
         [0031]    At the end of the washing operation as determined at step  170 , per step  172  the pump  110  stops and the valve  114  is closed, and the valves  102  and  36  are opened for the rinse operation. The open state of valves  102  and  36  allow a water and compressed air mixture to be delivered onto the wares (e.g., combined flow through the same nozzle(s) for rinsing for a predetermined time (e.g., which predetermined time can be set or varied). The compressed air may be introduced during the entire rinsing operation of the cleaning cycle or during only part of the rinsing operation. 
         [0032]    At the end of the rinsing as determined at step  174 , valve  36  is closed and valve  102  remains open so that compressed air (without any water) for drying is directed onto the wares for a drying operation of the cleaning cycle (e.g., for a predetermined time for a time as determined by a sensor that detects how dry the wares are) per step  176 . The heater  48  may be activated or otherwise controlled during the drying period based on air temperature and air quality factors/conditions such as humidity, moisture, etc. as indicated by the sensor(s)  46 . Moreover, the flowrate or amount of compressed air for drying may be controlled or set based upon, for example, the type of ware, shape, weight, etc. The valves  36 ,  114 ,  102  (and  108  if applicable) can be regulated/controlled (e.g., by the controller  150 ) to achieve various compressed air flows F 5  and/or F 5 ′, various wash liquid flows F 4  and various rinse water flows F 6  to achieve different water-to-air ratios and flows as necessary for desired wash, rinse and drying of the various wares types, such as heavy or light duty loads. 
         [0033]    While the above description primarily contemplates and automated machine  100 , in a manual machine or mode of the  FIG. 3  machine manual button presses may be used for initiating rack cleaning and/or any of initiating washing, starting the rinsing, starting the drying, etc. Moreover, the valves  36 ,  114 ,  102  (and  108  if applicable) could be controlled manually as well. 
         [0034]    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.