Abstract:
A food holding cabinet that has a plurality of food warming cavities. An ultrasonic misting device is disposed to provide mist to humidify at least one of the food warming cavities. The misting device comprises a well that holds water and a plurality of ultrasonic transducers. A controller actuates the ultrasonic transducers to produce a mist that is conveyed to the food warming cavity by a mist duct and a mist dispenser that distributes the mist evenly in the food warming cavity.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 60/966,104 filed on Aug. 24, 2007, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present disclosure relates to a method and food holding cabinet for providing humidity within the cabinet to keep food products moist. 
         [0004]    2. Discussion of the Background Art 
         [0005]    Traditionally, water has been heated up to create steam, which in turns creates humidity in a chamber. For example,  FIG. 1  shows a water heating tray that produces steam to provide humidity in a chamber of a food holding cabinet or of an oven. The steam comprises rather large droplets of water that result in uneven absorption by the food products. The steam generator component consumes a relatively large amount of electrical energy and requires considerable time to produce steam. 
         [0006]    Thus, there is a need to provide a method and a food holding cabinet that overcomes the disadvantages of the traditional food holding cabinets that use steam to provide humidity. 
         [0007]    The advantages of the present disclosure as compared to the traditional method are as follows:
   1) The present disclosure comprises a device that creates a mist made up of very minute droplets of water and requires lesser electrical energy as compared to larger droplets of water and higher energy of the conventional method of creating steam by heating water. As the droplets are significantly smaller, the mist can be absorbed more evenly and faster by the food products. The even absorption of moisture into the product improves product holding and maintains food quality as compared to using steam.   2) The misting device preferably uses ultrasonic technology that consumes significantly less electrical energy as compared to creating steam through heating up water.   3) The creation of mist through ultrasonic technology is considerable quicker than creating steam through heating up water.   
 
         [0011]    The present disclosure also provides many additional advantages, which shall become apparent as described below. 
       SUMMARY 
       [0012]    A method and system for generating fine water mist by means of ultrasonic transducers that are fitted at the base of a water tank, which is delivered to a food holding cabinet via a plurality of ducts. The device is housed within the food holding equipment to provide humidity thereto. 
         [0013]    A food holding cabinet of the disclosure comprises a plurality of walls that define a food holding chamber and an ultrasonic misting device disposed to inject a fine mist into the food holding chamber to provide a humid environment. 
         [0014]    In one embodiment of the food holding cabinet, the ultrasonic misting device comprises a well that holds a liquid and a plurality of ultrasonic transducers that agitate the liquid to produce the fine mist. 
         [0015]    In another embodiment of the food holding cabinet, the ultrasonic transducers are disposed in a bottom of the well. 
         [0016]    In another embodiment of the food holding cabinet, the ultrasonic misting device further comprises first and second float switches disposed in the well and a controller that responds to the operation of the first and second float switches to operate the ultrasonic transducers to agitate or not agitate the liquid. 
         [0017]    In another embodiment of the food holding cabinet, a mist dispenser distributes the fine mist evenly in the food holding chamber. 
         [0018]    In another embodiment of the food holding cabinet, a duct conveys the fine mist from the well to the mist dispenser. 
         [0019]    In another embodiment of the food holding cabinet, a plurality of tiers is provided and the fine mist is injected into a lower one of the tiers. 
         [0020]    A method of the disclosure provides humidity to a food holding chamber by operating one or more ultrasonic transducers to agitate a liquid to produce a fine mist and injecting the fine mist into the food holding chamber. 
         [0021]    In one embodiment of the method, a well is provided to hold the liquid. 
         [0022]    In another embodiment of the method, the operating step responds to a level of the liquid in the well to agitate or not agitate the liquid. 
         [0023]    In another embodiment of the method, the fine mist is distributed evenly in the food holding chamber. 
         [0024]    In another embodiment of the method, the food holding chamber comprises a plurality of tiers. The fine mist is injected into a lower one of the tiers. 
         [0025]    Further objects, features and advantages of the present disclosure will be understood by reference to the following drawings and detailed description in which like reference numerals denote like elements of structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a top front left-side perspective view of a conventional steam-based humidity creating system; 
           [0027]      FIG. 2  is a top front left-side perspective view of a first embodiment of the food holding cabinet with ultrasonic misting device according to the present disclosure; 
           [0028]      FIG. 3  is a top rear left-side perspective view of the ultrasonic tank of the ultrasonic misting device of the food holding cabinet of  FIG. 2 ; 
           [0029]      FIG. 4  is a top front right-side perspective view of the ultrasonic tank of ultra sonic misting device of the food holding cabinet of  FIG. 3 ; 
           [0030]      FIG. 5  is a bottom front right-side perspective of the ultrasonic tank of  FIG. 4 ; 
           [0031]      FIG. 6  is top front side perspective view of a second embodiment of the food holding device of the present disclosure; 
           [0032]      FIG. 7  is a top front perspective view of the food holding cabinet of  FIG. 6  with top and food racks removed; 
           [0033]      FIG. 8  is a top rear perspective view of the view of  FIG. 7 ; 
           [0034]      FIG. 9  is a perspective top perspective view of the ultrasonic misting device of the holding cabinet of  FIG. 6 . 
           [0035]      FIG. 10  is a top perspective view of the ultrasonic misting device of  FIG. 9  with top cover removed; and 
           [0036]      FIG. 11  is a bottom perspective view of the ultrasonic misting device of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0037]    Referring to  FIG. 2 , a first embodiment of a food holding device  20  according to the present disclosure comprises side walls  22  and  24 , a top wall  26  and a bottom wall  28  that define a food holding chamber  30  for keeping previously cooked food products warm. A plurality of food racks  32  and  34  divide food holding chamber into a top tier cavity  36 , a middle tier cavity  38  and a bottom tier cavity  40 . Separate transparent, see-through doors (not shown) cover middle tier cavity  38  and bottom tier cavity  40  so that customers may view food products being kept warm. 
         [0038]    Bottom tier cavity  40  is bounded at its lower extremity by a food product surface  42  formed in bottom wall  28 . An ultrasonic misting device  50  is disposed in bottom wall  28 . Ultrasonic misting device  50  is operable under control of a controller  48  to inject a fine mist in bottom tier cavity  40  to provide a humid environment. A control panel  52  is located in side wall  22  to provide user entered settings to controller  48 . Food products that need to be kept moist are suitably kept moist in bottom tier cavity  40 . Food products that do not require as much moisture are kept in middle tier cavity  38  and top tier cavity  36 . For example, top tier cavity  36  can hold pre-packed food products or crispy food products and middle tier cavity  38  can hold crispy food products. 
         [0039]    Referring to  FIGS. 3-5 , ultrasonic device  50  comprises a bottom wall  62  and at least one wall, and preferably four walls  54 ,  56 ,  58  and  60  that together with bottom wall  62  form a tank or well  64 . A top cover  66  (removed in  FIG. 3 ) covers well  64 . A pair of float switches  68  are disposed in well  64  and extend through side wall  54  for connection via electrical wires (not shown) to controller  48 . A misting duct  70  is disposed in well  64  and extends through top cover  66 . A drain port  72  is disposed in fluid communication with well  64 . A liquid inlet fitting (not shown) extends through bottom wall  62  into well  64 . The liquid inlet fitting is connected via tubing and a valve (not shown) to a source (not shown) of liquid, (e.g., water). A plurality of ultrasonic transducers  76  are affixed to bottom wall  62  and arranged in a spacing to provide adequate agitation to water in well  64  to produce a fine mist. Ultrasonic transducers  76  comprise terminals  78  for connection via electrical wiring to controller  48 . 
         [0040]    Controller  48  controls the filling of well  64  based on float switches  68 . When the water level dips below the lower float switch  68 , controller  48  responds by operating the liquid valve to supply water via the liquid fitting to well  64 . When the water level reaches the upper float switch  68 , controller  48  responds by operating the liquid valve to stop supplying water to well  64 . Optionally, well  64  can be filled manually when top cover  66  is removed. 
         [0041]    The fine mist is delivered to bottom tier cavity  40  via misting duct  70 . To more evenly distribute the mist in bottom tier cavity  40 , misting duct  70  is connected with a mist dispenser (or manifold)  80  as shown in  FIG. 2 . Mist dispenser  80  extends laterally across bottom tier cavity  40  to more evenly distribute the fine mist over food product surface  42 . 
         [0042]    In  FIG. 5 , the transducers  70  are shown arranged in two rows. It will be apparent to those skilled in the art that other arrangements can be used. Ultrasonic transducers  70  are operable in the wavelength range of 1650 KHz to 1750 KHz. 
         [0043]    Referring to  FIGS. 6-8 , a second embodiment of the food holding cabinet of the present disclosure is denoted by reference numeral  100 . Food holding cabinet  100  has some components that are identical to and bear the same reference numerals as components of food holding cabinet  20  of  FIG. 2 . 
         [0044]    Food holding cabinet  100  differs from food holding cabinet  20  in that the ultrasonic misting device and the interior of the bottom tier cavity are different. Referring to  FIGS. 7 and 8 , food holding cabinet  100  comprises an ultrasonic misting device  110  disposed on bottom wall  28 . A food tray  102  and a food tray  104  are also disposed on bottom wall  28  on opposite sides of ultrasonic misting device  110 . Food trays  102  and  104  are preferably removable to facilitate ease of cleaning and maintenance. An air duct  106  (shown only in  FIG. 7 ) extends between side walls  22  and  24  adjacent the front. 
         [0045]    Referring to  FIGS. 9-11 , ultrasonic misting device  110  comprises a well  114  disposed in a frame  116  and a cover  118  that covers well  114 . Frame  116  comprises side walls  120 ,  122 ,  124  and  126  and a bottom wall  128  that collectively form well  114 . Bottom wall  128  has a bottom portion  130  and a bottom portion  132 . Bottom portion  130  is horizontal and mates with bottom portion  132  and side walls  120 ,  122  and  124 . Bottom portion  132  ramps downwardly and mates with bottom portion  130  and side walls  120 ,  124  and  126 . Side wall  126  has a slope that ramps upwardly from the intersection with bottom wall portion  132 . Side wall  126  and bottom portion  132  are removed in  FIG. 11 . A misting duct  112  has one end disposed in well  114  and extends vertically through cover  118  to mate with mist dispenser  80  ( FIG. 8 ) to distribute mist evenly throughout the bottom tier cavity  40  to food trays  102  and  104 . 
         [0046]    Referring to  FIGS. 10 and 11 , a pair of float switches  134  are disposed in well  114  and extend through side walls  120  and  124  for connection via electrical wires (not shown) to controller  48 . One of the float switches  68  (upper float switch) is higher than the other (lower float switch). A drain pipe  144  is disposed in well  114  and extends through bottom wall portion  132  for connection to a drain fitting  142  that is connected to tubing (not shown) for disposal of liquid accumulated due to condensation of steam in lower tier cavity  40 . A liquid inlet fitting  140  extends through bottom wall portion  130  to provide liquid to well  114 . Liquid inlet fitting is connected via tubing and a valve (not shown) to a source (not shown) of liquid, (e.g., water). A plurality of ultrasonic transducers  136  is affixed to bottom wall portion  130  and arranged in a spacing to provide adequate agitation to water in well  114  to produce a fine mist. Ultrasonic transducers  136  comprise terminals  138  for connection via electrical wiring to controller  48 . 
         [0047]    Frame  116  further comprises a cover support  160  and side supports  146  and  148  that support well  114 . Side supports  146  and  148  are substantially identical so only side support  148  will be described in detail. Side support  148  is L-shaped and comprises a long leg portion  150  and a short leg portion  152  that extends toward side wall  122 . Side support  148  is shaped along a bottom edge to rest on bottom wall  128  of food holding cabinet  100 . Side support  148  at its end opposite shot leg portion  152  has an upwardly sloped edge  158  that mates with side wall  126 . Also at its opposite end, side support  148  has an upper portion  154  that serves as a support for cover  160 . Side support  148  further comprises a flange portion  156  (best seen in  FIG. 11 ) that supports side walls  120  and  122 . Upper portion  154  also provides support for side wall  120  and float switch  134 . Cover support  160  has a box structure that is supported by upper portions  154  of side supports  146  and  148 . 
         [0048]    Cover  118  is situated within cover support  160  and is removable for ease of cleaning and maintenance. Cover  118  comprises a large part  162  and a small part  164  that are joined by a hinge  166 . Small part  164  is rotatable through hinge  166  between an open position shown in  FIG. 9  and a closed position (not shown) in which it rests in cover support  160 . A drain cover  168  is disposed in cover part  166  and is in registry with drain pipe  144  when cover part  166  is in the closed position. 
         [0049]    Controller  48  controls the filling of well  114  based on float switches  134 . When the water level dips below the lower float switch  134 , controller  48  responds by operating the liquid valve to supply water via the liquid inlet  140  to well  114 . When the water level reaches the upper float switch  134 , controller  48  responds by operating the liquid valve to stop supplying water to well  114 . Optionally, well  114  can be filled manually when top cover  118  is opened or removed. 
         [0050]    While several embodiments in accordance with our present disclosure have been shown and described, it is to be clearly understood that the same may be susceptible to numerous changes apparent to one skilled in the art. Therefore, the disclosure is not limited to the details shown and described but intend to show all changes and modifications that come within the scope of the appended claims.