Abstract:
A portable food tray pre-wash and water recycling apparatus and method for pre-washing reusable food trays prior to placement in a separate cleaning and sanitizing unit that significantly reduces water wasted in kitchen and scullery areas. The apparatus includes a portable cabinet having a slot in a top end for inserting a food tray, laterally opposed spray nozzles beneath the slot that spray both sides of the tray, laterally opposed rotating brushes beneath the nozzles that scrub the tray, a tray support and brush comb member that supports the tray in a vertical position and removes particles from the brushes, a series of removable incrementally smaller gauge filters vertically spaced beneath the brushes that slide in from one side to filter the water, a water reservoir beneath the filters, a heating unit to heat and disinfect the filtered water, and a pump that recycles heated water back to the nozzles.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims priority of U.S. Provisional Application Ser. No. 60/643,480, filed Jan. 13, 2005. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to food tray cleaning apparatus, and more particularly to a portable food tray pre-wash and water recycling apparatus and method that pre-washes food trays prior to placement in a separate cleaning and sanitizing unit and significantly reduces water wasted in kitchen and scullery areas aboard marine vessels, and in industrial, commercial, and institutional cafeterias. 
   2. Background Art 
   The present invention is directed toward an apparatus and method that pre-washes reusable food trays of the type that have compartments or shallow recesses formed in which food is placed, such as those used aboard marine vessels, and in industrial, commercial, and institutional cafeterias, prior to their placement in a separate cleaning and sanitizing unit and recycles the water used in the pre-wash operation. The advantage of reusable compartmented food trays is that the purchasing, stocking, distributing, collecting and washing is reduced to a single item. The main disadvantage is the requirement for washing the trays after each meal, and the amount of water wasted in the cleaning operation. 
   Typically, in the tray cleaning operation, after dumping the food from the trays, and prior to placing them in a conventional tray washing machine for cleaning and sanitizing, the trays are subjecting to a “scraping stage” where the food refuse is manually scraped from the trays and they are manually sprayed with water by a hand-held water jet nozzle with a squeeze trigger to remove the remaining food debris. The trays are usually manually sprayed for approximately 10 seconds per tray, and approximately 50 oz. of water is utilized with a conventional water jet nozzle. After use, the sprayed water is considered wastewater or “graywater” and is not recycled or reused. 
   Based on daily feed charts used by cooks aboard a naval frigate, it is estimated that a crew of 200 men will use about 445 trays per day in port (docked), and about 650 trays per day underway (at sea). Thus, in the example of a crew of 200 men, the amount of water used (wasted) daily by the conventional manual spraying method would be about 173.8 gallons per day in port (docked), and about 253.9 gallons per day underway (at sea). The amount of water wasted in this simple operation is significantly greater aboard larger vessels with larger crews, such as an aircraft carrier with a crew of 6,000. The amount of water wasted in this simple operation aboard aircraft carrier with a crew of 6,000 would be about 5,214 gallons per day in port (docked), and about 7,617 gallons per day underway (at sea). 
   Graywater is defined as the combined effluent wastewaters or drainage from shipboard galleys, sculleries, dishwashers, laundries, showers, sinks, and washbasins. Many ships directly discharge graywater, without treatment, into navigable waters, including lakes and waters near the shoreline. Some ships are equipped with concentration, holding, and transfer tanks for the purpose of storing graywater until it can be pumped to a dockside sanitation system. Graywater discharges in the past have not been subjected to permitting or regulatory requirements; however, as a result of increasingly stringent water quality standards being imposed under state, national, and international regulations, wastewater offload and disposal costs in domestic and foreign ports and harbors continue to increase. 
   These same problems are also present in industrial, commercial, and institutional cafeterias, that utilize reusable food trays in feeding large numbers of people. 
   Thus, there remains a need for an effective and economical means to reduce wastewater effluent, particularly graywater discharges from marine vessels, and to significantly reduce water wasted in kitchen and scullery areas in industrial, commercial, and institutional facilities. 
   There are several patents that are directed toward tray washing apparatus of various constructions, most of which are large, complex, elongate conveyor type apparatus that include a washing compartment and a sterilizing compartment, and associated mechanisms for receiving and transporting the trays through the compartments. 
   O&#39;Connor, U.S. Pat. No. 2,651,065 discloses a tray washing and sterilizing machine having a slot in a top end of a side wall for inserting a food tray, spray nozzles, and a pair of rotating brushes at an upper end that spray and scrape both sides of the tray, and a removable filter screen (47) beneath the brushes that slides in from one side to filter the water, a water reservoir beneath the filters, a heating unit to heat and disinfect the water, and a pump to pump the heated water to the spray nozzles and to another set of nozzles in an adjacent sterilizing compartment. The trays are fed through the slot and pre-washed and then sterilized in the adjacent sterilizing compartment. 
   Kleebauer, U.S. Pat. No. 3,178,745 discloses a movable machine for washing plastic shields of fluorescent lights, which has a slot in a top end of a side wall for inserting a flat plastic panel, spray nozzles, and a pair of rotating brushes at an upper end that spray and scrape both sides of the panel, and two water reservoirs beneath the brushes, and a pump to pump recycle the water to the spray nozzles. 
   Richard, U.S. Pat. No. 3,938,533 discloses an automatic scullery apparatus for automatically processing carrying trays having used culinary items and refuse thereon that collects and cleans reusable culinary items (e.g. knives, forks and spoons), separates and disposes of waste, and cleans the trays without need for operating personnel. In preferred embodiments, the apparatus automatically stacks the cleaned trays and sorts and collects the cleaned reusable culinary items by type so that the trays and the culinary items are readily available for reuse. 
   Kitterman et al, U.S. Pat. No. 3,939,854 discloses a tray washing system that includes conveyors which transport compartmented food service trays from a tray receiving mechanism to inverting and scraping mechanisms and through washing, rinsing and drying mechanisms to a stacking mechanism. The receiving mechanism restricts trays to insertion in a predetermined orientation in which the food receiving surfaces face upwardly, and the inverting mechanism inverts each tray so that the food receiving surface faces downwardly. As each tray is inverted, the scraping mechanism discharges substantially the entire contents of a cleaning fluid reservoir onto the food receiving surface of the tray, and thereby dislodges refuse and silverware that may be on the tray. The washing, rinsing and drying mechanism apply a water-detergent solution, rinse water, and drying air to the trays, respectively, and the stacking mechanism deposits the trays onto a mobile self-depressing tray receiver. The tray washing system further includes a silverware separating and soaking mechanism comprising a chute which receives cleaning fluid and refuse and silverware entrained therein, a dam which removes the heavier silverware from the cleaning fluid, and a door in the bottom of the chute for dropping the silverware into a soaking sink. 
   Pure, U.S. Pat. No. 4,281,675 discloses a washing apparatus for washing insulated trays that includes an endless conveyor below the elevation of first and second guide rails that guide the trays in an upright disposition as they are being washed. The conveyor includes generally V-shaped tray supports at spaced points therealong so that each tray is supported by two adjacent tray supports. Vertically disposed manifolds have spraying nozzles for spraying water generally horizontally at opposite major faces of the trays. 
   Kleber, U.S. Pat. No. 5,581,836 discloses a compact wall-mounted or countertop-supported washing and sanitizing unit for cleaning and drying food service trays as well as other articles after being serially loaded in an upright manner in guide tracks that lead through the unit so that the trays process one at a time through adjacent washing and drying stations of the unit. After being manually loaded, an operator by exerting a displacement force on a last loaded tray urges preceding trays through the unit by virtue of their edge-to-edge physical contact. 
   The present invention is distinguished over the prior art in general, and these patents in particular by a portable food tray pre-wash and water recycling apparatus and method that pre-washes reusable food trays prior to placement in a separate cleaning and sanitizing unit and significantly reduces water wasted in kitchen and scullery areas aboard marine vessels, and in industrial, commercial, and institutional cafeterias. The apparatus includes a portable cabinet having a slot in a top end for inserting a food tray, laterally opposed spray nozzles beneath the slot that spray both sides of the tray, laterally opposed rotating brushes beneath the nozzles that scrub the tray, a tray support and brush comb member that supports the tray in a vertical position and removes particles from the brushes, a series of removable incrementally smaller gauge filter members vertically spaced beneath the brushes that slide in from one side to filter the water, a water collection reservoir beneath the filters, a heating unit to heat and disinfect the collected filtered water, and a pump to recycle the heated water back to the spray nozzles. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention to provide a portable food tray pre-wash and water recycling apparatus and method that pre-washes food trays prior to placement in a separate cleaning and sanitizing unit which will significantly reduce water wasted in kitchen and scullery areas aboard marine vessels, and in industrial, commercial, and institutional cafeterias. 
   It is another object of this invention to provide a portable food tray pre-wash and water recycling apparatus that method that conserves water by recycling water used in tray cleaning operations that would otherwise be classified as wastewater or graywater. 
   Another object of this invention is to provide a portable food tray pre-wash and water recycling apparatus that utilizes a series of vertically spaced incrementally sized filter members that filter the water, which are easily accessible and removable for installation and cleaning. 
   Another object of this invention is to provide a portable food tray pre-wash and water recycling apparatus that utilizes rotating brushes wherein food particles and residue are automatically removed from the brushes during rotation. 
   Another object of this invention is to provide a portable food tray pre-wash and water recycling apparatus that is self-contained in a relatively small cabinet and does not require complex, elongate conveyor apparatus for receiving and transporting the trays or multiple washing and sterilizing compartments. 
   A further object of this invention is to provide a portable food tray pre-wash and water recycling apparatus that is used as an adjunct to existing conventional tray washing and sterilizing apparatus. 
   A still further object of this invention is to provide a portable food tray pre-wash and water recycling apparatus that is simple in construction, inexpensive to manufacture and rugged and reliable in operation. 
   Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related. 
   The above noted objects and other objects of the invention are accomplished by a portable food tray pre-wash and water recycling apparatus and method that pre-washes reusable food trays prior to placement in a separate cleaning and sanitizing unit and significantly reduces water wasted in kitchen and scullery areas aboard marine vessels, and in industrial, commercial, and institutional cafeterias. The apparatus includes a portable cabinet having a slot in a top end for inserting a food tray, laterally opposed spray nozzles beneath the slot that spray both sides of the tray, laterally opposed rotating brushes beneath the nozzles that scrub the tray, a tray support and brush comb member that supports the tray in a vertical position and removes particles from the brushes, a series of removable incrementally small gauge filter members vertically spaced beneath the brushes that slide in from one side to filter the water, a water collection reservoir beneath the filters, a heating unit to heat and disinfect the collected filtered water, and a pump to recycle the heated water back to the spray nozzles. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the portable food tray pre-wash and water recycling apparatus in accordance with the present invention. 
       FIG. 2  is a cross sectional view of the portable food tray pre-wash and water recycling apparatus taken along line  2 - 2  of  FIG. 1 . 
       FIG. 3  is a cross sectional view of the portable food tray pre-wash and water recycling apparatus taken along line  3 - 3  of  FIG. 1 . 
       FIG. 4  is a cross sectional top view of the portable food tray pre-wash and water recycling apparatus taken along line  4 - 4  of  FIG. 1 . 
       FIG. 5  is a cross sectional view of the portable food tray pre-wash and water recycling apparatus taken along line  5 - 5  of  FIG. 2 , showing the chain and sprocket and meshed gear drive arrangement of the roller brushes. 
       FIG. 6  is an isometric view of the comb and tray support member of the portable food tray pre-wash and water recycling apparatus. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings by numerals of reference, there is shown in  FIGS. 1-4 , a preferred a portable food tray pre-wash and water recycling apparatus  10  that pre-washes reusable food trays of the type in which food is placed, prior to their placement in a separate cleaning and sanitizing unit and recycles the water used in the pre-wash operation. Typically, these types of trays T are of a rectangular shape approximately 14″×11″×1″ and have shallow recessed compartments for holding various food items. 
   The portable food tray pre-wash and water recycling apparatus  10  includes a generally rectangular housing or cabinet  11  having side walls  12 A and  12 B, end walls  13 A and  13 B, a bottom wall  14 , and a top wall  15 . Access doors  12 C and  13 C may be provided on the side wall  12 A and end wall  13 B, respectively, or both end walls. Interior walls  16 A and  16 B spaced a short distance inwardly from, and parallel to, the end walls  13 A and  13 B extend vertically between the top and bottom walls  15  and  14  and transversely between the side walls  12 A and  12 B. 
   The top wall  15  is provided with a longitudinal horizontal slot  17  communicating with the interior of the cabinet  11 , which is sized to allow manual insertion of a tray T inserted vertically downward therethrough from one end or side. In a preferred embodiment, the cabinet  11  is approximately 24″ wide, 28″ deep, and 48″ tall, and is supported on caster type wheels  18  for portability and transporting it to a desired location, and each wheel is provided with a wheel lock  18 A to prevent it from moving after being positioned at the desired location. 
   As shown schematically in  FIG. 2 , a control panel  19  is mounted in the door  13 C of the end wall  13 B, or other suitable location, and houses the electrical circuitry for operating the apparatus  10 . Electrical power is supplied to the apparatus through a power cord  20  connected with the electrical circuitry in the control panel  19  and controlled by an on-off switch  21  on the control panel. 
   A water reservoir  22  is mounted in the lower portion of the cabinet  11 . In a preferred embodiment, the reservoir  22  is sized to contain a volume of 25 gallons of water. An electric heating element  23  is mounted in lower portion of the reservoir and is connected with power source through the electrical circuitry in the control panel  19  and is controlled by a temperature control knob  23 A mounted on the control panel. A thermometer or water temperature sensor  24  is mounted in mid portion of the reservoir  21  and is connected through the electrical circuitry with a temperature gauge or display  24 A on the control panel  19 . A water level sensor  25  is mounted in the reservoir  21  and is connected through the electrical circuitry with a water level gauge or display  25 A on the control panel  19 . 
   A generally rectangular duct  26  having inwardly tapered side walls  26 A is mounted in the cabinet  11  above the reservoir  22  to channel return water into the top end of the reservoir (as described hereinafter). 
   A reservoir fill conduit F connected in fluid communication with the interior of the reservoir  22  extends through the interior wall  16 A and has a valve V 1  at its outer end for connection to a hose for filling the reservoir with water. A reservoir drain conduit D connected in fluid communication with the interior of the reservoir  22  extends through the interior wall  16 A and has a valve V 2  at its outer end for connection to a hose for draining water from the reservoir. 
   An electric motor  27  is mounted in the cabinet  11  on the bottom wall  14  beneath the reservoir  22  and has a shaft  27 A connected to a water pump  28  through a conventional coupling  29 . The intake of the water pump  28  is connected to the interior of the reservoir  22  by a conduit  30 , and its outlet is connected to a water supply conduit  31 . As best seen in  FIGS. 2 ,  3  and  4 , the water supply conduit  31  extends through the interior wall  16 A and vertically upward and is adjoined to a pair of laterally spaced conduits  32  by a tee  33 . The laterally spaced conduits  32  extend through the interior wall  16 A and are disposed horizontally at the upper end of the cabinet  11  just below the slot  17  in the top wall  15  in opposed relation at opposite sides of the slot, and are joined in fluid communication with the water pump  28  by the conduit  31 . 
   The laterally spaced conduits  32  have spray nozzles  34  mounted along their length in opposed relation, at opposite sides of the slot  17 , respectively, which are joined in fluid communication therewith. The spray nozzles  34  are positioned to direct opposed high pressure water sprays angularly downward against the respective top and bottom surfaces of a tray T inserted vertically through the slot  17  from one end or side (as indicated in dashed line), and prevent water from escaping from the cabinet  11  through the slot. 
   Referring again to  FIG. 2 , the electric motor  27  has a second shaft  27 B on the side opposite the water pump  28  that extends through an aperture in the interior wall  16 B and has a drive sprocket  35  at its outer end. 
   An upper pair of roller brushes  36 A and  36 B are rotatably mounted in the upper end of the cabinet  11  just below the laterally spaced conduits  32  and spray nozzles  34  in horizontally opposed relation, and are spaced apart a sufficient distance such that their bristles will engage and scrub the respective top and bottom surfaces of the tray T inserted vertically through the slot  17 . A lower pair of horizontally opposed roller brushes  36 C and  36 D are rotatably mounted in the upper end of the cabinet  11  a short distance vertically below the upper pair of brushes, and are also spaced apart a sufficient distance such that their bristles will engage and scrub the respective top and bottom surfaces of the tray T inserted vertically through the slot  17 . 
   As best seen in  FIGS. 2 ,  4  and  5 , the shafts  37 A,  37 B,  37 C and  37 D of the brushes  36 A,  36 B,  36 C and  36 D are journalled at one end in the interior wall  16 A and their other end extends through an aperture in the interior wall  16 B and have gears  38 A,  38 B,  38 C and  38 D mounted thereon, respectively. The teeth of the upper pair of gears  38 A and  38 B are engaged with each other and the teeth of the lower pair of gears  38 C and  38 D are engaged with each other such that they rotate in opposed direction, as shown by the arrows in  FIG. 5 . The teeth of one upper gear  38 B and the teeth of one lower gear  38 D are both engaged with an idler gear  39  rotatably mounted on the interior wall  16 B. A sprocket  40  is secured to the lower gear  38 C and is connected by an endless chain  41  to the drive sprocket  35  of the electric motor  27 . In operation, both the upper pair and lower pair of roller brushes  36 A,  36 B and  36 C,  36 D rotate in opposite directions toward the center of the cabinet so as to direct food residue and particles dislodged from the surfaces of the tray vertically downward. 
   Referring now additionally to  FIG. 6 , an elongate comb and tray support member  42  is mounted in the cabinet  11  at its upper end. The comb and tray support member  42  is a generally rectangular wire frame having four vertical legs  42 A and a bottom portion  42 B with parallel spaced longitudinal and transverse cross members  42 C disposed beneath the lower pair of roller brushes  36 C and  36 D. A pair of vertically spaced upper and lower comb members  43 A,  43 B and  43 C,  43 D extend horizontally between vertical legs  42 A on the opposed longitudinal sides of the comb and tray support member  42  and each has a row of longitudinally spaced apart teeth or fingers  44  of sufficient length to engage the bristles of the respective roller brush during rotation to dislodge food residue and particles from the brush bristles. 
   The bottom portion  42 B of the comb and tray support member  42  is disposed a distance vertically below the top of the cabinet  11  such that the cross members  42 C engage and support the lower end or side of the tray T inserted vertically through the slot  17  in the top end of the cabinet. 
   A series of generally rectangular filters  45 A,  45 B and  45 C are slidably mounted horizontally in vertically spaced relation in the cabinet  11  between the bottom of the comb and tray support member  42  and the water reservoir  22 . The horizontal filters  45 A,  45 B and  45 C are similar to a cabinet drawer and are slidably received through respective vertically spaced horizontal slots  46  in the side wall  12 A of the cabinet  11 . Suitable seals are provided between the filters and the slots to form a watertight seal when the filters are in their fully retracted position in the cabinet. The outer end walls of the filters  45 A,  45 B and  45 C may be provided with a handle or knobs  47  for easily removing the filter screens when it becomes necessary for cleaning. 
   Each of the filters  45 A,  45 B and  45 C is of a progressively smaller gauge size with the largest at the top  45 A and the smallest  45 C at the bottom. The uppermost or first filter  45 A is of a gauge sufficient to restrict passage of larger food items, such as bones, fruit cores, and peelings, and may be a screen. The intermediate filter  45 B is of a gauge sufficient to restrict passage of smaller food particles, such as rice, crumbs, and kernels of corn and may also be a screen. The lowermost filter  45 C is of a very fine gauge that filters the water before it passes into the reservoir  22 . It should be understood that the lowermost filter  45 C may be formed of a fibrous material rather than a screen. 
   OPERATION 
   After manually dumping the uneaten food from the trays and scraping the food refuse from the trays into a garbage container, the trays are usually stacked at a location close to the existing conventional food tray washing and sanitizing machine. In a typical tray cleaning operation, the reservoir of the portable food tray pre-wash and water recycling apparatus is initially filled with water and placed at a location near the stacked trays and the existing conventional food tray washing and sanitizing machine. The heater is turned on and set to heat the water to a desired temperature. The temperature setting may be determined by the type of food being served. 
   After reaching the desired water temperature, the motor is turned on to operate the pump and rotate the brushes while the pumped water is sprayed through the nozzles. The operator then takes a tray from the stack and manually inserts it generally vertically into the slot in the top wall of the cabinet such that it is received and supported on the brush comb and tray support member. As the tray is inserted downwardly through the slot, hot water sprayed from the nozzles is directed onto opposed sides of the tray simultaneously, and as it continues downwardly it passes through the bristles of the counter-rotating laterally opposed brushes, which scrub the opposed sides of the tray simultaneously. The tray is left in its vertically supported position for approximately 3 seconds, and then removed. The fingers of the brush comb and tray support member dislodge particles from said brushes as they rotate. 
   The sprayed water passes through the series of progressively smaller gauge size filters and is captured in the reservoir and recycled back through the nozzles. The uppermost filter restricts passage of larger food items, such as bones, fruit cores, and peelings; the intermediate filter restricts passage of smaller food particles, such as rice, crumbs, and kernels of corn; and the lowermost filter filters the water before it passes into the reservoir. It should be understood that the filters may be easily inspected and removed as necessary. 
   The pre-washed trays are stacked and are then ready to be placed in the existing conventional food tray washing and sanitizing machine. The pre-washing operation prevents food refuse and debris from being introduced in to the existing conventional food tray washing and sanitizing machine. 
   In a preferred embodiment, the reservoir contains a volume of 25 gallons of water, which, as an example, is adequate to service a naval frigate having a crew of 200 men, which would use about 445 trays per day in port (docked), and about 650 trays per day underway (at sea). 
   In this example the reservoir of the present portable food tray pre-wash and water recycling apparatus would not require draining until after the third meal of the day. Thus, in the example of a crew of 200 men, the amount of water saved by the present pre-washing method is estimated to be about 148.8 gallons per day or 4464 gallons per month in port (docked), and about 228.9 gallons per day or 6867 gallons per month underway (at sea). 
   While this invention has been described fully and completely with special emphasis upon preferred embodiments, it should be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.