Abstract:
For cooking/heating a food product, a simpler yet more effective carousel system is used in a microwave and/or infrared, and hot oil and/or hot gas oven; a continuous oven surface cleaning system is included; and an improved hot oil/gas heating and circulating device is used in conjunction with the improved carousel system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a utility application based on the U.S. Provisional application No. 60/348,209, Filed Nov. 9, 2001, and No. 60/340,917, Filed Dec. 12, 2001 and claims the benefit of same. 
     
    
     
       STATEMENTS REGARDING FEDERALLY SPONSOR RESEARCH OR DEVELOPMENT  
         [0002]    Not applicable.  
         REFERENCE TO A MICROFICHE APPENDIX  
         [0003]    Not applicable.  
         BACKGROUND OF THE INVENTION  
       Description of the Related Art  
         [0004]    The current invention is an improvement over the U.S. patent, “System of Cooking or Heating Food Products with Microwaves and Hot Oil” issued to the current inventor on Jun. 30, 1998 (U.S. Pat. No. 5,771,786). The above mentioned patent will be referred to as “the existing patent” hereafter.  
           [0005]    The existing patent involves a method and a device for cooking and heating food products using microwaves and hot oil simultaneously in an oven. As a preferred embodiment, the oven uses a carrousel system for a continuous input of food products to be processed in the oven. The carousel system also provides a continuous output of the processed food products from the oven. All input and output operations can be performed from one operator position with the carousel system.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    The current improvements over the existing patent include, (a) a simpler yet more effective carrousel system is used in the microwave and hot oil oven, (b) a continuous oven surface cleaning system is included and (c) an improved hot oil heating and circulating device is used in conjunction with the improved carrousel system.  
           [0007]    It should be noted that, although microwave with different wavelengths is commonly used to generate heat in household cooking or industrial food processing, other waves in the electromagnetic spectrum such as the infrared radiation or visible light, with shorter wavelength than microwave, can also be used to generate heat. Furthermore, other hot convective media such as hot gas can be used as a convective medium. The current invention uses microwave and hot oil oven as the preferred embodiment. In its generality, the current invention includes the use of any other hot convective medium or a combination of hot convective media and any other wave or a combination of waves in the electromagnetic spectrum.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0008]    For a fuller understanding of the invention, the following drawings are provided in conjunction with the detail descriptions of the invention, which will be presented in the next section:  
         [0009]    [0009]FIG. 1A is an illustration of the sectional side view of the preferred embodiment of the present invention with microwave and hot oil as the heating means.  
         [0010]    [0010]FIG. 1B is an illustration of the top view of the present invention shown in FIG. 1A.  
         [0011]    [0011]FIG. 1C is an illustration of the sectional side view of the preferred embodiment of the present invention with microwave and hot gas as the heating means.  
         [0012]    [0012]FIG. 1D is an illustration of the sectional side view of the preferred embodiment of the present invention with microwave and combined hot oil and hot gas as the heating means.  
         [0013]    [0013]FIG. 2 is an illustration of the partial sectional front view of the exhaust system.  
         [0014]    [0014]FIG. 3 is an illustration of the oblique view of the outer conductor walls of the oven showing the boundary surface of the microwave field.  
         [0015]    [0015]FIG. 4 is an illustration of the partial sectional side view of the microwave and hot oil oven.  
         [0016]    [0016]FIG. 5 is an illustration of the sectional top view of the microwave and hot oil oven.  
         [0017]    [0017]FIG. 6 is an illustration of one embodiment of the food compartment basket carrying food products around the carrousel.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    With reference to FIG. 1A, the current invention mainly includes a carousel  8  within an microwave and hot oil oven  10  with a main drive shaft  27  and a carousel drive shaft  57 , a food receptacle compartment  11 , an oil heater system  12 , an exhaust system  40  and an enclosure  39  for the entire system. The top view of this embodiment is shown in FIG. 1B.  
         [0019]    As shown in FIGS. 1A and 1B, the oven  10  is tilted with an angle with respect to a horizontal plane such as the oil surface  22 . The lower portion of the oven is submerged in the oil within the heater system  12 . The hot oil feeds into the oven  10  and returns to the heater system  12  through relatively small holes on the perforated walls  36 , which are indicated by a dotted line in FIG. 1A. The oil is heated with one or more heating element  13  in the oil heater system  12 . Due to natural heat convection, the heated oil flows upward and enters oven  10  through the perforated wall  36 . Using a partition  19 , the oil returning from oven  10  is guided towards the other side of the heater system  12 , making an oil-circulation loop as depicted by the arrows in FIG. 1A. The moisture generated from the frying food products and being carried out of oven  10  by the returned oil, settles on the bottom  23  of the heater system  12 . This water on the bottom of the heater system is drained out of the system periodically by means of a commercially available suction device (not shown). An oil filter set  14  is used to remove the food particles in the oil, before the oil returns back for reheating in the region where the heating element  13  is located. The filter set  14  is removable for cleaning. To further remove the food particles in the oil, a commercially available motor-driven continuous filter system (not shown) can be installed in the system as an optional device. In operation, a thermostat (not shown) placed in the oil within the heater system  12  is used to control the oil temperature.  
         [0020]    During operations, the exhaust system  40  uses one or more blowers to suck the fresh air into oven  10  through openings  38  on the food receptacle compartment  11  as well as through an opening  20  on the door  66  of enclosure  39 . The fresh air drawn into oven  10  mixes with water vapor and oil particles generated in the oven. This mixture along with bubbles on the oil surface, if it is generated, is then drawn out of oven  10  through the perforated wall  37  as shown in FIG. 1A. The oil particles, the moisture and possibly bubbles in the exhaust are removed by a series of filters before the exhaust air reaches the outlet  61 . FIG. 2 shows the partial sectional front view of an embodiment of the exhaust system  40 . In this embodiment, the exhaust air is sucked into the exhaust system from inlet  70  by two symmetrical blowers (not shown). The exhaust air is then filtered by an initial filter  71  and a subsequent filter  72  before it reaches the two outlets  61 . An optional oil drain hole  24 , shown in FIGS. 1A and 2, is used to drain the excessive oil and water, which are produced from the initial filtering of the exhaust air by filter  71  and are settled on the bottom of the exhaust duct. With this option, the accumulated oil and water on the bottom of the exhaust system  40  is then sucked out of the system periodically with a commercially available suction device (not shown) through suction hole  26  shown in FIGS. 1A and 2. As shown in FIGS. 1A and 1B, the top part of the oil heater is partially covered by a flat plat  35 , which is welded or connected airtight to the outer edge of the oven  10 . Both the flat plat  35  and the oven  10  keep any oil particle and water vapor from getting into the upper part of enclosure  39 .  
         [0021]    As shown in FIGS. 1A and 1B, a number of magnetrons  15  are installed on the upper wall of the oven  10 , which generates a microwave field confined by the conductor walls of oven  10  and the conductor walls of the food receptacle compartment  11 . These conductor walls, which define the boundary of the microwave field, are further illustrated in FIG. 3. In order to keep the magnetrons from being stained by the oven grease, the magnetrons can be isolated from the oven cavity by a glass or other non conductor which transmits the microwave energy emitted from the magnetrons.  
         [0022]    With reference to FIG. 3, the shaded area  63  above a portion of the food receptacle compartment  11  is made of a dielectric material and is at the same level as the oven floor  63   a . This shaded area  63  makes up a portion of the oven floor  63   a . An opening at  45  shown in FIG. 3, between the shaded area  63  and the boundary line  64  of the conductor oven floor  63   a , is provided for receiving the cooked or heated food products to the food receptacle compartment  11 . When the individual food product in oven  10  is moving over the opening  45  by the rotating carousel  8 , it is dropped down to the food receptacle compartment  11  through the opening at  45 . This transferring of the processed food products into the receptacle compartment  11  will be described in more detail later. The opening at  45  also serves as the air passageway for the air intake from hole  38  (illustrated in FIG. 1A) to the oven  10 .  
         [0023]    The system enclosure  39  is made of a conductor material. The enclosure  39  has a front door  66  with a door handle  67  as depicted in FIG. 1A. An optional safety switch (not shown) is built on door  66 , such that it automatically shut off the microwave power when the door is opened. As will be described in more detail later with an illustration in FIG. 4, the oven  10  has a door with an independent safety shutoff switch. As mentioned previously, when the oven  10  is in use, the microwave field is confined within the conductor walls of oven  10  and the conductor walls of food receptacle compartment  11 . Any leakage of the microwave energy out of this confinement will be detected by a microwave leak detector  18 , which is installed within the enclosure  39  as shown in FIG. 1A. In a case of microwave leakage, detector  18  triggers an automatic shutoff of the microwave power.  
         [0024]    As shown in FIG. 1A, the main drive shaft  27  of the oven is driven by a pulley  16 , which is driven by an electric motor  17 . The drive mechanism as well as the carousel  8 , which convey the food products in the oven  10 , will be described in more detail later with illustrations in FIGS. 4 and 5.  
         [0025]    As shown in FIG. 4, as an embodiment of the carousel system, a shaft  56 , which is made of a conductor material, is connected to the pulley  16  at one end. Its other end  54  is connected to the end  55  of the main drive shaft  27 , which is made of a dielectric material. The end  54  and the end  55  are coupled with a square or other non-circular shaped coupling. It should be noted that, in this embodiment, the surface of the end of the shaft  56  at  54  is also a part of the above mentioned boundary surface of the microwave field. The other end of the main drive shaft  27  is rotating on a stationary piece  41  during operation. The stationary piece  41 , which is made of either a conductor material or a low friction dielectric material, is rigidly mounted on the floor  63   a  of the oven  10 . To minimize the frictional force between the end of the drive shaft  27  and a stationary surface, an optional ball bearing made of a dielectric material can be used to replace the stationary piece  41 .  
         [0026]    As depicted in FIGS. 4 and 5, a number of sweeper frames  28 , which are made of a dielectric material, are connected rigidly to the main drive shaft  27  in the radial directions. The shape, the dimension and the position of each of the sweeper frames  28  are designed in such a way that the outer edge of the frame is close to but not contacting the inner surface of oven  10 . Each of the frames  28  has a groove along its outer edge, which houses a relatively thin and soft dielectric sweeper strip  29  in such a way that part of the strip  29  is secured in the groove and the outer edge of the strip  29  lightly touches the inner surface of the oven  10 . In operation, the shaft  27  drives the sweeper frames  28  to a rotational motion and the sweeper strip  29  wipes and cleans the inner surface of the oven  10 .  
         [0027]    The frames  28  are also rigidly connected to a carousel drive shaft  57  as well as a circular basket holder  52  as shown in FIGS. 4 and 5. As depicted in FIG. 5, to secure the removable food compartment basket  43  (to be described in further detail below) on the carousel system, the tip  50  of the compartment basket  43  is inserted in a hole  49  on the carousel drive shaft  57 . As illustrated in FIG. 4, the compartment basket  43  is also secured by the basket holder  52  by means of a hook  58 , which attaches the basket  43  to the basket holder  52 . The main function of the basket holder  52  and the hook  58  is to hold down the basket  43  on to the oven floor  63   a , when the basket is submerged in the oil with a food product in it.  
         [0028]    With reference to FIG. 5, a compartment basket  43  in the carousel system in operation is shown at  44 . The lines  42  indicate the borderlines between the compartment baskets  43  in the carousel system. Many such compartment baskets  43  installed in position constitute the food conveying mechanism for the current microwave and hot oil carousel oven system. The food products to be processed in the oven  10  are placed individually in the compartment basket  43 . FIG. 6 shows one embodiment of the compartment basket  43 . Other embodiments can be designed by one skilled in the art. The compartment basket  43  which is made of a dielectric material has bars  59  confining the individual food product  46  at the top as well as at the two sides of the basket. The bottom of the basket, however, is opened and the food product in the basket contacts the oven floor  63   a  in operation. The bars  59 , the cylindrical inner sidewall of oven  10 , the oven floor  63   a  and the outer surface of the carousel drive shaft  57  constitute the stationary as well as the moving confinement boundaries of the individual food product in the compartment basket  43 . The food product is confined within these boundaries when it is cooked or heated in the compartment basket, which is driven by the carousel  8  and is rotating on the oven floor  63   a.    
         [0029]    During operations, the individual food product in the compartment basket  43  is initially out of the hot oil region, but is cooked or heated by microwave energy alone. It then gradually enters the hot oil region and being cooked or heated simultaneously by both the hot oil and the microwave energy. At the final stage, the food product is out of the hot oil region again and is continue to be cooked or heated by the microwave energy until it is removed from the oven. When each basket  43  reaches the position above the opening of the oven floor  63   a  at  45  (shown in both FIGS. 3 and 5), the individual food product in the basket will drop down to the food receptacle compartment  11  (Please see FIG. 3 for location of receptacle compartment  11 ) through the opening. If the carousel rotational direction  65  as shown by the arrow in FIG. 5 is chosen, the opening at  45  will be located as depicted, such that the individual food product will drop down to the receptacle compartment  11  prior to reaching the front center of oven  10 . The food receptacle compartment  11  may include a Teflon slide (not shown) or the like beginning proximate boundary line  64 . The shaded area  63  in FIG. 5 represents the portion of the oven floor  63   a  made of a dielectric material as described previously with the illustration in FIG. 3. It should be noted that if the food products to be processed are relatively small loose pieces such as French fries, such food products can be placed in another confinement as a group, such as in a meshed bag made of a dielectric material. This meshed bag is then placed in the compartment basket  43  for processing in oven  10 .  
         [0030]    Shown in FIGS. 4 and 5 is a front door  47  of oven  10 . Air inlet holes  38  on door  47  shown in FIG. 4 are provided for the intake of the fresh airs into oven  10 . When the operator opens the door  47 , the microwave power as well as the power to drive the carousel system is automatically shut off. The operator can then place the food products to be cooked or to be heated into the food compartment basket  43 . The operator also removes the cooked or heated food products from the food receptacle compartment  11  while the door  47  is opened. To resume the microwave as well as the carousel operations, door  47  must be closed and the system switch  69  shown in FIG. 1A must be in the “on” position. When the system switch  69  is in the “off” position, all system power is shut off. An optional delay switch can be provided for the exhaust system  40 . This delay switch allows the exhaust system to continue running for a period of time after the system switch is turned off.  
         [0031]    As described earlier, the hot oil enters oven  10  and the air exhausts from oven  10  through relatively small holes on the perforated walls of oven  10 . The holes  51  on the oven floor  63   a  of oven  10  as well as the holes  68  on the cylindrical sidewall of oven  10 , as depicted in FIGS. 4 and 5, are small enough to keep the microwave from leaking through the walls.  
         [0032]    The top of the oven  10  can be separated from the bottom part of the oven at the joint line  62  shown in FIG. 4, by a simple removal of the binding means such as screws. When the top is removed, the shaft  56  and the main drive shaft  27  can be separated at their coupling point. This removal of the oven top is designed to be relatively easy for the purpose of a periodical cleaning of the carousel mechanism inside the oven  10 .  
         [0033]    The present cooking or heating system that is discussed so far, using the microwave and hot oil, can be replaced by a system using the microwave and hot gas, typically hot air. The system can also be replaced by a system using the microwave and combined hot oil and hot gas. The system using the microwave and hot gas is illustrated in FIG. 1C. It is shown that the previous oil heater system is replaced by a hot gas system  82 . Similar to the system using hot oil, the hot gas is heated by the heater system  13  and enters the oven  10  through the perforated wall  36 . Using a blower  80 , the hot air is sucked out of oven  10  and blown through the filter system  14  before entering the heater region. It is shown by the arrows, the air-circulation loop is formed with a natural heat convection above the heater system  13  as well as the forced convection created by the blower  80 . In operation, the blower (not shown) in the exhaust system  40  is turned off. The blower in the exhaust system  40  can be turned on periodically to blow out the hot gas that has been circulated in the system.  
         [0034]    The other system using the microwave and combined hot oil and hot gas is illustrated in FIG. 1D. This system includes the previously discussed oil heater system  12  as well as a hot gas generator  85  as depicted in FIG. 1D. The hot gas generator  85  has a gas inlet  87 , through which the unheated gas enters the hot gas generator. The hot gas generated is then fed into oven  10  through outlet  86  of the hot gas generator and the opening at  45  (shown in both FIGS. 3 and 5) between the oven floor and the receptacle compartment  11 . During operation, the blower (not shown) in the exhaust system  40  is turned on to blow out the hot gas as well as the unwanted moisture and possibly bubbles from frying as mentioned earlier.  
         [0035]    Some or all of the magnetrons  15  could also comprise, by way of example but without limitation, other electromagnetic wave generator(s) or light bulbs, such as, for example, a source for a wave in the infrared range of the electromagnetic spectrum.