Abstract:
A warewasher for washing wares includes a chamber for receiving wares. The chamber has an associated liquid delivery system for spraying liquid onto wares within the chamber. A tank collects the sprayed liquid. A liquid recirculation system moves liquid from the tank back to the liquid delivery system. A drain system is located within the tank. The drain system includes a well, a liquid recirculation system inlet within the well and a drain opening within the well. A drain control assembly includes a drain stopper member and a strainer connected with the drain stopper member. When the drain stopper member is positioned to block flow through the drain opening, the strainer is positioned to block passage of tableware into the well. The strainer is mounted for sliding movement along a length of the drain stopper member enabling, when the drain stopper member is raised slightly to permit flow out of the drain opening, the strainer to remain in position to block passage of tableware into the well.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 60/872,031, filed Nov. 30, 2006. 
     
    
     TECHNICAL FIELD 
       [0002]    This application relates generally to pass through type warewasher systems which are used in commercial applications such as cafeterias and restaurants and, more particularly, to such a warewash system including a drain system having combined drain and pump intake. 
       BACKGROUND 
       [0003]    Commercial warewashers commonly include a housing area which defines washing and rinsing zones for dishes, pots pans and other wares. In certain zones, 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. Occasionally, the water is drained from the tank through a drain for a cleaning operation. The drain may be separate from the pump intake. 
       SUMMARY 
       [0004]    In an aspect, a warewasher for washing wares includes a chamber for receiving wares. The chamber has an associated liquid delivery system for spraying liquid onto wares within the chamber. A tank collects the sprayed liquid. A liquid recirculation system moves liquid from the tank back to the liquid delivery system. A drain system is located within the tank. The drain system includes a well, a liquid recirculation system inlet within the well and a drain opening within the well. A drain control assembly includes a drain stopper member and a strainer connected with the drain stopper member. When the drain stopper member is positioned to block flow through the drain opening, the strainer is positioned to block passage of tableware into the well. The strainer is mounted for sliding movement along a length of the drain stopper member enabling, when the drain stopper member is raised slightly to permit flow out of the drain opening, the strainer to remain in position to block passage of tableware into the well. 
         [0005]    In another aspect, a method of operating a warewasher is provided. The method includes delivering a liquid to a chamber of the warewasher using a liquid delivery system. The liquid is received in a tank located below the chamber. Draining of the liquid in the tank through a drain opening of a drain system is prevented using a plug portion of a drain control assembly located within a drain body of the drain system. Liquid is filtered through a strainer of the drain control assembly as the liquid enters the drain body. The strainer is moveable relative to the drain control assembly while being connected thereto. The liquid is recirculated using a liquid recirculation system including a liquid recirculation inlet in communication with the drain body. The liquid recirculation system delivers liquid to the liquid delivery system. 
         [0006]    In another aspect, a warewasher for washing wares includes a chamber, a liquid delivery system configured to deliver liquid to the chamber and a tank at the bottom of the chamber for collecting liquid. A liquid recirculation system is configured to move liquid from the tank to the liquid delivery system. A drain system includes a drain body that receives liquid from the tank, a recirculation system inlet through which liquid can be drawn from the drain body and a drain opening through which liquid can be drained from the drain body. A drain control assembly includes a support member and a strainer slidingly supported by the support member such that the strainer moves relative to the support member. The drain control assembly is configured to be located at the drain system such that the strainer strains liquid flowing into the drain body. 
         [0007]    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 
         [0008]      FIG. 1  is a diagrammatic side, section view of an embodiment of a warewash system; 
           [0009]      FIGS. 2 and 3  are side, section views of an embodiment of a drain system in a closed configuration for use with the warewash system of  FIG. 1 ; 
           [0010]      FIGS. 4 and 5  are side, section views of the drain system of  FIGS. 2 and 3  in an open configuration; 
           [0011]      FIGS. 6-10  are various views of another embodiment of a drain system; 
           [0012]      FIGS. 11 and 12  illustrate operation of a system for use in opening and closing the drain system; 
           [0013]      FIGS. 13 and 14  are side, section views of another embodiment of a drain system in closed and open configurations; and 
           [0014]      FIG. 15  is a perspective view of another embodiment of a warewasher. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    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  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 . 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 . As will be described below, a drain system  36  provides a single location where liquid is pumped from the tank  30  using the pump  32  and where liquid can be drained from the tank, for example, for a tank cleaning operation. 
         [0016]    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. 
         [0017]    The warewash system  10  may optionally include a power rinse 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. 
         [0018]    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 ,  58  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 ,  58 . The water then drains from the wares into tank  50 . The rinsed rack  12  of wares  14  then exit the final rinse chamber  54  through curtain  66 , moving into dryer unit  18 . 
         [0019]    Referring now to  FIGS. 2 and 3 , drain system  36  is shown in a closed configuration where liquid is prevented from draining from the tank  30 , for example, to maintain liquid level within the tank. A drain control assembly  51  includes a cylindrical pump strainer  70  (e.g., formed of stainless steel or other suitable material such as plastic) that overlies a drain body or well  72  and a plug portion or stopper  74  that, in the illustrated closed configuration, prevents liquid from flowing from the well through a drain port  76 . A pump intake  78  (in the illustrated case, an opening in the well sidewall) is in communication with the well  72  for allowing the pump  32  to draw strained liquid from the well during use. With the drain system  36  in the closed position, pump strainer  70  is seated against an upper tank surface  77  about the periphery of the well  72 , to limit ingress of large items that could be pulled into the pump intake, and the stopper  74  is seated against a bottom surface  79  of the well  72 , forming a seal that prevents liquid from exiting the well through the drain port  76 . 
         [0020]    A lever system  80  is provided so that the drain control assembly  51  can be moved from the closed configuration to an open configuration illustrated by  FIGS. 4 and 5 . The pump strainer  70  and stopper  74  are connected to each other by an outer stalk  82 . Outer stalk  82  includes a bore  84  that receives an inner stalk  86 , which is connected to a lever arm  88 . Lever arm  88  can be pivoted in the direction of arrow  90  from the position illustrated in  FIGS. 2 and 3  to the position illustrated in  FIGS. 4 and 5  using pull bar  92 . At one end, pull bar  92  includes a slot  94  that receives a projection  96  that is sized to slide within the slot. At an opposite end, pull bar  92  includes a handle  98  that is graspable by a user to allow the user to pull the pull bar away from the drain which causes the stopper  74  and pump strainer  70  to raise (e.g., about one inch). With the drain system  36  in the open position, liquid including sediment and food particles can flow beneath the pump strainer  70 , into the well  72  and out the drain port  76 . Typically, the pump  32  is turned off so that particles will not flow into the pump with the drain system  36  in the open configuration. In some embodiments, bottom  101  is slanted downwardly toward the drain system  36  to facilitate movement of particles toward the drain system with the drain system in the open configuration. 
         [0021]    A solenoid  100  is used to maintain the pull bar  92  in the open configuration. The pull bar  92  is spring biased toward the closed configuration. To place the drain system  36  in the closed configuration, a trigger  102  is actuated which actuates the solenoid  100  and allows the pull bar  92  to move under the force of a spring to the closed position illustrated by  FIGS. 2 and 3 . While the spring is not shown in  FIGS. 2-5 , it could be located in chamber  103  (see spring element  105  of  FIGS. 11 and 12 ). In some embodiments, a position sensor  104  (e.g., an electronic eye) is used to monitor the position of the pull bar  92 . Sensor  104  may be connected to a controller that determines when the drain system  36  is opened. The controller may be capable of controlling pump  32 , for example, so that when the drain system  36  is in the open configuration, the pump is automatically turned off. As another example, the controller may provide an indication to the user that the drain system  36  is in the open configuration. Pull bar  92  and handle  98  provide easy access to the user to open and close the drain from a location outside the tank  30 . In some embodiments, the pump strainer and stopper can be removed from the inner stalk  86 , for example, to remove them from the tank  30 . 
         [0022]      FIGS. 6-10  illustrate an alternative drain system embodiment  120  for use with the tank  30  including pump inlet  78  and drain port  76  that are both in communication with well  72 . A drain control assembly  128  is used to control draining of liquid from the tank  30 . The drain control assembly  128  includes a support member (e.g., in the form of a standpipe  130 ) that supports a strainer  132  thereon.  FIG. 6  illustrates the drain control assembly  128  removed from the well  72 . A drain plug portion  134  is located at an end of the standpipe  130 , which can be positioned within the drain port  76  to prevent liquid from passing thereby. The drain plug portion  134  includes a tapered end  135  that is used to guide the drain plug portion into the drain port  76 . 
         [0023]    Referring briefly to  FIG. 6A , the standpipe  130  includes an opening  131  extending from an upper end  133  of the standpipe through the tapered end  135 . A deflector  141  may be included that is connected at the upper end  133  to the standpipe  130 . The deflector  141  is spaced from the upper end  133  to allow liquid to pass therebetween during an overflow condition. The deflector  141  prevents large food particles and tableware (or other objects) from entering the opening  131 . 
         [0024]    Referring back to  FIG. 6 , the strainer  132  includes a wall  137  that extends about the standpipe  130  (e.g., in a cylindrical manner). The wall  137  includes openings through which liquid can pass while preventing passage of particles (e.g., large food particles) or other items such as tableware (e.g., knives, spoons, forks, etc.) thereby. A solid upper wall  136  covers a top of the wall  137 . The upper wall  136  includes an opening sized to slidingly receive the standpipe  130 . Other strainer shapes and configurations are contemplated. The upper wall  136  may also include strainer openings. 
         [0025]    Referring now to  FIG. 7 , the strainer  132  and standpipe  130  are moveable relative to each other.  FIG. 7  (and  FIG. 6A ) illustrates the strainer  132  in its fully lowered position, while  FIG. 6  shows the strainer in its fully raised position relative to the standpipe  130 . In some embodiments, the deflector  141  is at a height h 1  relative to the bottom end of the standpipe  130  that is greater than about two times (e.g., about three times or more) a height h 2  of the top of the strainer  132  from the bottom end of the standpipe  130  with the strainer at its fully lowered position (see  FIG. 6A ). Referring to  FIG. 8 , as the drain control assembly  128  is lowered into the well  72 , the strainer  132  rests on the bottom surface of the tank  30 . The combination of the tank surface and strainer  132  prevents passage of potentially obstructing items into the well  72 . 
         [0026]      FIG. 9  illustrates the drain control assembly  128  in a configuration to allow strained liquid to drain through the drain port  76 . In this configuration, the drain plug portion  134  of the standpipe  130  is lifted away from the drain port  76 . The standpipe  130  may be lifted mechanically into this position and/or manually. As can be seen, in this position, the strainer  132  remains seated against the bottom of the tank  30 . Thus, a user can effect tank draining by lifting the standpipe  130  slightly, without lifting the strainer  132  from its blocking position. 
         [0027]    To prevent draining of liquid through the drain port  76 , the standpipe  130  and drain plug portion  134  are lowered relative to the strainer  132 . A seal member  136  (e.g., an O-ring) is provided on the drain plug portion  134  to provide a seal between the drain port  76  and the drain plug portion. With the drain plug portion  134  sealed with the drain port  76 , filtered liquid can be drawn into the recirculation system from the well  72  and provided to the liquid delivery system while liquid is prevented from draining from the tank through the drain port. As can also be seen in  FIG. 9 , a stop  137  (e.g., a snap ring) is located on the standpipe  130  to prevent the strainer  132  from sliding thereby and off of the standpipe, for example, when the drain control assembly  128  is removed from the well  72  (e.g., for a cleaning operation). The stop  137  is located far enough down on the standpipe  130  to allow the standpipe to be removed from the drain port  76  while the strainer  132  remains seated against the bottom of the tank. The stop  137  may be removable to facilitate separation of the strainer  132  from the standpipe  130 . There may be another stop located above the strainer  132  on the standpipe  130  to prevent the strainer from being raised off of the standpipe. In the head  139  of the standpipe there is an enlarged end that can act as a stop.  FIG. 10  shows the strainer  132  in a raised position with the drain plug portion  134  located in the drain port  76 . 
         [0028]    Referring again to  FIG. 9 , in some embodiments, a tube member  138  is connected to the upper wall  136  of the strainer  132 . The tube member  138  includes an opening through which the standpipe  130  extends. The tube member  138  interacts with the standpipe  130  to provide lateral stabilization of the strainer  132  on the standpipe. The opening of the tubular member  138  or may be free sliding. 
         [0029]    The drain system embodiment of  FIGS. 6-10  is an assembly that is arranged to be manually inserted and removed. However, such an assembly could be linked with a mechanical system (such as those described herein) for triggering tank drain operations. 
         [0030]      FIGS. 11 and 12  illustrate an example of a drain lift linkage  140  for use in lifting an lowering the standpipe  130 . The drain lift linkage  140  includes a support bracket  142  that is mounted on an upper surface  144  of a pump housing  146 . The support bracket  142  slidably supports a moveable member  148  that includes a pair of L-shaped slots  150  and  152  within which fasteners  154  and  156  are received. The moveable member  148  includes an engageable end  160  that includes a graspable portion  162  that can be grasped and pulled by an operator to lift the moveable member and pull the moveable member toward the operator. Due to the L-shape of the slots  150  and  152 , the moveable member  148  can remain in the raised position until a horizontal force is applied thereto. The moveable member  148  is connected to a connector  164  that connects the standpipe  130  to the moveable member. In particular, the connector  164  is illustrated as being releasably engaged with the deflector  141 , however, other configurations are possible. 
         [0031]      FIG. 11  illustrates the standpipe  130  positioned in the raised position by the drain lift linkage  140 . The slots  150  and  152  are sized such that moveable member  148  can be raised only so high (e.g., about ¾ inch) as to lift the standpipe  130  from the drain port  76  to allow liquid to pass therethrough while the strainer  132  remains seated against the bottom of the tank  30 . 
         [0032]      FIG. 12  illustrates the standpipe  130  in the lowered position, blocking the drain port  76 . To place the standpipe  130  in the lowered position from the raised position, an operator can exert a horizontal force on the moveable member  148  thereby aligning the fasteners  154  and  156  with the vertical portions of the slots  150  and  152 . The weight of the standpipe  130  causes the standpipe and the moveable member  148  to drop, thereby locating the standpipe within the drain port  76 . In one embodiment, door  166  includes a ledge  168  that extends outwardly from the door. The ledge  168  is sized and positioned so as to contact the graspable portion  162  with the moveable member  148  in the raised position and the door  166  closed to apply the horizontal force to the moveable member to cause the standpipe to lower into its lowered position. This can prevent the standpipe  130  from being in the raised position if the door  166  is closed. The ledge  168  may also be sized so that is does not contact the graspable portion  162  with the moveable member  148  in its lowered position. The standpipe  130  and strainer  132  assembly can be removed from the drain port  76  for cleaning. 
         [0033]    The above-described drain systems and drain control assemblies can provide a number of advantages. For example, by locating both the pump intake  78  and drain port  76  within a single well, cleaning of the warewasher  10  can be simplified. Additionally, locating the pump intake  78  at the drain port  76  places the pump intake below the bottom of the tank  30  thereby increasing the head above the intake. This increase in head above the pump intake  78  can improve performance of the pump  32 . 
         [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. For example, a foot pedal may be used to open and close the drain system.  FIGS. 13 and 14  show an alternative strainer  106  that is cone-shaped. Additionally, the drain systems (represented by the dotted lines) can be utilized in other non-conveyor type machines, such as warewasher  110  illustrated by  FIG. 15  or an undercounter warewasher. Accordingly, other embodiments are contemplated and modifications and changes could be made without departing from the scope of this application.