Batch dishware washing machine with steam venting

A batch ware washing machine and/or related method of washing wares. The machine includes a moveable door which partially encloses a steam cavity. When the door is in the up or open position, hot moist air may be forcibly pulled from the steam cavity and into an exhaust plenum via an air inlet port that is strategically positioned above the top wall of the door when the door is in the closed position, but below the top wall when the door is in the open position. A controller causes the air to be forcibly pulled through the plenum for a predetermined exhaust time period, such as one minute, and then automatically stops the forced air exhaust movement. The exhaust plenum may be ducted directly to the outside of the surrounding building. The air conditioning load on the HVAC units serving the kitchen are reduced, thereby reducing energy consumption.

BACKGROUND

The present invention is generally directed to food dishware washing devices, and more particularly to a device that washes wares with an improved steam exhaust technique, and related methods.

Restaurants and other food service establishments typically employ numerous devices to clean their plates, cups, glasses, utensils, and the like, collectively referred to in the art as “dishware” or simply “wares”. One common example is a dishwashing machine. While dishwashing machines are also found in household settings, commercial dishwashing equipment differs in that they are typically faster and must meet numerous additional requirements, such as those dictated by health codes. Faster cleaning allows the food service establishment to have a lower inventory of wares, which takes up less physical space and lowers operating costs. However, health codes typically require that each piece of ware be rinsed by at least a certain minimum amount of water at or above a certain temperature (such as 180° F.), with the intent being that the surfaces of the ware will therefore necessarily reach at least a certain temperature in order to kill any bacteria that may be present thereon.

The use of hot water for rinsing tends to create hot moist air, sometimes referred to as steam, in the ware rinse area. Many typical ware washing machines allow this steam to enter the surrounding kitchen when the washing machine door is opened. Other ware washing machines employ a continuously-on exhaust fan to exhaust the steam into the surrounding kitchen. Further still, many ware washing machines are required to be placed under continuously running vent hoods so that the escaping steam may be vented outside the building. However, all of these approaches have proven less than satisfactory, primarily due to their excess energy consumption. As such, there remains a need for alternative approaches to ware washing machines and related methods, particularly approaches that result in better overall energy consumption.

SUMMARY

The present invention provides a batch ware washing machine and/or related method of washing wares. The batch ware washing machine includes a moveable door which partially encloses a steam cavity. When the door is in the up or open position, hot moist air may be forcibly pulled from the steam cavity and into an exhaust plenum via an air inlet port that is strategically positioned above the top wall of the door when the door is in the closed position, but below the top wall when the door is in the open position. A controller causes the air to be forcibly pulled through the plenum for a predetermined exhaust time period, such as one minute, and then automatically stops the forced air exhaust movement. The exhaust plenum may be ducted directly to the outside of the surrounding building. By limiting the time period that air is exhausted, and by exhausting the air to the outside rather than the kitchen area, the air conditioning load on the HVAC units serving the kitchen are reduced, thereby reducing energy consumption.

In one aspect, the present invention provides a batch ware washing machine that comprises a base unit and a moveable multi-sided door. The base unit has a plurality of output nozzles for delivering wash fluid and rinse fluid to a ware wash area. The moveable door defines a downwardly open steam cavity and is moveably mounted to the base unit for movement between a closed position to an open position. The door has a front wall, first and second lateral sidewalls disposed on opposing sides of the front wall, and a top wall. The door first and second lateral sidewalls may be disposed generally orthogonal to the front wall of the door. The steam cavity is upwardly bounded by the top wall and laterally bounded by the first and second sidewalls. The base unit has a rear wall rearwardly bounding the steam cavity and disposed opposite the front wall. A plenum is disposed in the rear wall. The rear wall comprises first and second air input ports leading to the plenum. The ware washing machine further comprises a controller operative to control drawing of air through the plenum. With the door in the closed position: 1) the door is lower than in the open position; 2) the door laterally and upwardly encloses the wash area; 3) first input port is disposed below the top wall and operatively interconnects the steam cavity to the plenum; and 4) the second input port is disposed above the door. With the door in the open position: 1) the door is higher than in the closed position; 2) the steam cavity is disposed above the wash area; 3) the wash area is open laterally; 4) the second input port is disposed below the top wall of the door and operatively connects the steam cavity with the plenum. The controller is configured to: a) cause air to be forcibly drawn in through at least the first input port and through the plenum for a predetermined time period; and b) thereafter, automatically cause the cessation of air being forcibly drawn through the plenum. The time period may be approximately one minute.

The controller may be configured to cause air to be forcibly drawn in through both the first and second input ports and through the plenum for the predetermined time period. The rear wall may have a plurality of forwardly extending lateral flanges disposed laterally outboard of the door in the open position. The batch ware washing machine may further comprise a duct opening to the plenum on one end and opening on the other end external to a building surrounding the base. The batch ware washing machine may further comprise a fan operative to draw air through the plenum and controlled by the controller. The fan may be disposed external or internal to the base unit. The door may be pivotally mounted to the base unit. There may be third, fourth, fifth, etc. inlet ports disposed a similar height above the second inlet port as the first inlet port (such as in a line or the like); each leading to the plenum.

In another aspect, the present invention provides a method of cleaning dishware, comprising washing and rinsing dishware in a wash area of a dishware machine while a multi-sided door in a closed position laterally and upwardly encloses the wash area. Thereafter, while the door remains in the closed position, forcibly drawing air into a generally vertically flowing plenum from a cavity defined by the door from via at least a first air inlet port disposed below a top wall of the door. Thereafter: a) moving the door upward to an open position above the closed position to laterally expose the wash area and move the cavity upward; and b) forcibly drawing air from the upwardly moved cavity into the plenum via at least a second air inlet port disposed below the top wall of the door when the door is in the open position, but above the top wall when the door is in the closed position. Thereafter, automatically ceasing the forcible drawing in of air to the plenum. The duration of the forcible drawing of air into the plenum is a first predetermined time period. The first predetermined time period may be approximately one minute.

The method may further comprise feeding output of the plenum directly to one end of a duct, the opposing end of the duct terminating outside a building that surrounds the dishware machine. The method may be such that, after the moving of the door to the open position, air is forcibly drawn into the plenum via the first and second inlet ports. The method may further comprise indicating the expiration of a second predetermined time period prior to the moving of the door to the open position; wherein the second time period begins with the initiation of forcibly drawing air into the plenum. The second time period may be approximately ten seconds. The forcibly drawing air into the plenum via at least a second air inlet port when the door is in the open position may comprise forcibly drawing air into the plenum via a fan disposed external to the dishware machine and operatively connected thereto by an intervening duct. The fan may be disposed external to a building housing the dishware machine. The forcibly drawing air into the plenum via at least a second air inlet port when the door is in the open position may comprise forcibly drawing air into the plenum via a fan disposed internal to the dishware machine and operatively connected to an exhaust duct that terminates outside a building that surrounds the dishware machine. The moving the door upward to the open position may comprise moving the door in a pivoting fashion.

The various optional features and aspects described above and below may be used alone or in any combination.

DETAILED DESCRIPTION

In one embodiment, the present application is directed to a batch ware washing machine and/or related method of washing wares. The batch ware washing machine includes a moveable door which partially encloses a steam cavity. When the door is in the up or open position, hot moist air may be forcibly pulled from the steam cavity and into an exhaust plenum via an air inlet port that is strategically positioned above the top wall of the door when the door is in the closed position, but below the top wall when the door is in the open position. A controller causes the air to be forcibly pulled through the plenum for a predetermined exhaust time period, such as one minute, and then automatically stops the forced air movement. The exhaust plenum may be ducted directly to the outside of the surrounding building. By limiting the time period that air is exhausted, and by exhausting the air to the outside rather than the kitchen area, the air conditioning load on the HVAC units serving the kitchen are reduced, thereby reducing energy consumption.

FIG. 1shows a kitchen area of building5, such as a restaurant, nursing home, or the like. A batch ware washing machine, generally indicated at10, is located in the kitchen, advantageously in proximity to an outer wall7. An exhaust duct70connects the washing machine10to the outer wall7, and provides a route for exhausting hot moist air from the washing machine10to outside the building5. As such, an inlet end72of the exhaust duct70attaches to the washing machine10, and an outlet end74of the exhaust duct70terminates at or beyond the outer wall7so as to direct the exhaust outside the building5. A fan80is operatively connected to the exhaust duct70to force air/steam to move through the exhaust duct70. The fan80may be disposed on the outer wall7or elsewhere as described below. The fan80operates under the control of controller18of the ware washing machine10, as discussed further below.

As shown inFIG. 2, the washing machine10includes a base unit12and a door50moveably supported by the base unit12. The base unit12includes a cabinet14for housing controller18, one or more water heaters19, wash/rinse equipment22, and other components of the washing machine10known in the art. An operator interface panel16is located on the front of the base unit12, and includes suitable gages, switches, and indicator lights17as known in the art. The wash/rinse equipment22, advantageously including nozzles24on rotatable arms, is disposed in a well21in the base unit12, as shown inFIG. 2. The wash/rinse equipment22supplies wash fluid and rinse fluid to the ware wash area20formed by base unit12and door50to clean the wares therein. The well21forms the lower extent of the ware wash area20, and the door50(in the closed position) forms the upper, front, and lateral sides of ware rinse area20. A rear wall30of the base unit12provides the rear wall of the ware rinse area20. The rear wall30of base unit12extends upward above the well21and provides a location for moveably mounting the door50.

As indicated above, the door50is moveably mounted to the base unit12. For the embodiment ofFIG. 2, the door50is indirectly mounted to the base unit12via pivoting handle51. A counter-weight mechanism may be associated with handle51to facilitate easy opening of the door50. Door50includes a top wall58, a front wall52, and a left lateral side wall54and a right lateral side wall56. The walls52,54,56,58are advantageously disposed so as to form a generally rectangular enclosure, with an open bottom and an open rear. The rear wall30of the base unit12is disposed behind the door50, and acts as a rear wall for the cavity60formed by the door50. Because this cavity60typically encloses hot moist air (“steam”) during the washing process, this cavity bounded by the walls of door50may be referred to as the steam cavity60. The door50is movable between a closed position, where the door50laterally and frontwardly encloses the ware wash area20, and a raised or open position where the door50is disposed higher than in the closed position and does not laterally enclose the ware wash area20, so that wares may be loaded and unloaded from the ware wash area20. As can be appreciated, when the door50is in the closed position, the steam cavity60and the ware rinse area20overlap so that the steam cavity60is coincident with part of the ware wash area20, above the well21. Note that to contain the fluids sprayed during the wash cycle, the interface between the lower edge of the door50and the base unit12should be sufficiently sealed to prevent the liquid from escaping, but advantageously open enough to allow the drawing in of air, as explained further below.

The wash/rinse equipment22supplies wash fluid and rinse fluid to the ware wash area20during the wash cycle. During the rinse portion of the wash cycle, hot water is sprayed in the ware wash area20via nozzles24. Typically, the hot water is sprayed for a sufficient time so that the wares reach a mandated temperature, such as 180°. The hot water causes steam to be generated, which the washing machine10exhausts using a novel approach that utilizes a pair of inlet ports42,44disposed on rear wall30and control of the exhaust air flow, as discussed further below. Although any suitable configuration of wash/rinse equipment22known in the art may be used, the wash/rinse equipment22may advantageously take a configuration similar to that shown in U.S. Patent Application Publication No. 2010/0051063.

A pair of air inlet ports42,44are disposed on rear wall30, with inlet port42disposed higher than inlet port44. The inlet ports42,44lead to plenum34which is disposed inside rear wall30. The plenum34extends downward to at least inlet port44, and upward to the top of rear wall30. The plenum34may be approximately the same cross-sectional size as the interior of the rear wall30, or may advantageously be smaller, such as partially defined by a partition32internal to rear wall30. The plenum34is operatively connected to exhaust duct70at plenum outlet36so that air leaving plenum34is exhausted outside of the building5. The lower inlet port44is vertically positioned below the level of the top wall58of door50when door50is in the closed position so that the lower inlet port44provides an airflow path between the steam cavity60and the plenum34when the door50is closed. Advantageously, the vertical position of the lower inlet port44also allows the lower inlet port44to open to the steam cavity60when the door50is in the open position, although this is not required in all embodiments. The upper inlet port42is disposed higher than the lower inlet port44so that the upper inlet port42is vertically positioned above the door50when the door50is closed, but below the door top wall58when the door50is in the open position. Thus, the upper inlet port42provides an airflow path between the steam cavity60and the plenum34when the door50is open.

To wash the wares, the door50is moved to the open (raised) position (step210), and the wares, typically loaded on a ware tray, are loaded into the ware wash area20(step220). The door50is then closed, and the wash cycle is initiated, either automatically or via user input at the operator interface panel16(step230). The wash/rinse equipment22, optionally including the nozzles24, are then used to spray wash fluid (e.g., water and detergent) in the ware wash area20. When the wash portion of the wash cycle is complete, the wash/rinse equipment20, including nozzles24, then spray rinse fluid (e.g., hot water) in the ware wash area20. Either during the spraying of the rinse fluid, or at the conclusion thereof, the controller18causes the fan80to turn on so as to forcibly draw air from the steam cavity60. The fan80forces air out of the plenum34, with that air being replaced by air input to the plenum34from the steam cavity60via the lower air inlet port44, with that air in turn replaced by ambient air from the kitchen (entering the wash area20via the interface between the lower edge of the door50and the base unit12). During this initial draw-out of air, the indicator17should indicate to the user that the wash cycle is not yet complete. This initial draw-out of air lasts a predetermined time period T2(step240), after which the “done” indicator17may change status to indicate to the user that the door50can be raised (step250). The length of time period T2may be adjusted as desired, but a period of approximately ten seconds is believed appropriate for most situations. The door50is then raised to the open position (step260), so that the steam cavity60is raised upward and the door50does not laterally bound the ware wash area20. The user may then remove the wares, if desired. It should be noted that the fan80continues to run at this point, forcing airflow through the plenum34. However, with the door50in the open (raised) position, the steam cavity60is now able to supply air to the plenum34via the upper inlet port42. Thus, air is drawn from the steam cavity60via the upper inlet port42(and optionally also the lower inlet port44), into the plenum34, to the duct70, and exhausted outside the building5. After a predetermined time period T1(step270), the fan80is stopped (step280). The length of time period T1may be adjusted as desired, but a period of approximately one minute (e.g., about forty-five seconds to about seventy-five seconds, more preferably about sixty seconds) to is believed appropriate for most situations. This duration allows for the hot air to be exhausted from the steam cavity60, while minimizing the amount of excess ambient air from the kitchen that is exhausted. Thus, there is less “make up” air that the kitchen HVAC system needs to condition, as less air has been removed from the kitchen.

In some embodiments, the base unit12may include forwardly extending side flanges38attached to the rear wall30. These flanges38advantageously laterally overlap the rear portion of door50, and act to help contain the steam in steam cavity60.

In some embodiments, the fan80may be located on outer wall7of building5, with suitable electrical connections to controller18so that controller18may control the operation of fan80. In other embodiments, a fan80may be additionally or alternatively internal to ware washing machine10. For example, fan80may be disposed at the exhaust end of plenum34, internal or external to rear wall30.

In some embodiments, an automatic interlock (not shown) may be used to ensure that door50stays closed during time period T2. For example, controller18may control interlock so that the door50is locked in the closed position until the expiration of time period T2, and thereafter release the interlock so that door50may be raised by the operator.

Note that the discussion above has assumed that time periods T1, T2start with the initiation of the wash cycle. An equivalent approach is to start time periods T1, T2from the start of the wash cycle, with suitable adjustments to their duration.

Note further that, in some embodiments, there may be an additional open exhaust hood above the ware washing machine10, but such is not required, and the ware washing machine10may be located away from an open exhaust hood because the steam is vented out of the building even when the door50is open.

The ware washing machine10allows for a shortened cycle time because in the door up position (FIG. 3), the door50with the rear wall30allows the cavity60to act as an exhaust hood above the wares that continue to exhaust steam and heat produced in the washing/rinse cycles as well as the steam and heat coming off the wares in the door open opposition.

All U.S. patents, patent application publications, and applications mentioned above are hereby incorporated herein by reference in their entirety.