Patent Publication Number: US-2007102418-A1

Title: Rotisserie oven and hood

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This is a continuation-in-part of U.S. patent application Ser. No. 10/428,796 filed May 2, 2003, which is a continuation-in-part of U.S. patent application Ser. No. 10/078,845, filed Feb. 19, 2002, now issued as U.S. Pat. No. 6,608,288, the disclosures of each of which are hereby incorporated by reference as if set forth in their entirety herein. This further claims priority to U.S. Provisional Patent Application 60/467,518, filed May 2, 2003, the disclosure of which is hereby incorporated by reference as if set forth in its entirety herein. 
    
    
     BACKGROUND OF THE INVENTION  
      I.  
      The present invention relates generally to cooking apparatuses, and in particular to rotisserie ovens.  
      Rotisserie ovens are traditionally used to cook raw meat and poultry product, such as chicken, duck, and the like in side a cooking chamber. In particular, the food product to be prepared is carried by a rotating spit assembly that brings the food product into communication with a radiating heat source that cooks, and in some cases browns the outer surface of, the food product.  
      Unfortunately, conventional rotisserie ovens suffer from several drawbacks. For instance, if the door to the cooking chamber is not sufficiently sealed, flavorful gasses may escape from the oven. Furthermore, conventional ovens allow condensation to accumulate on the interior surface of the glass door, thereby inhibiting a user&#39;s ability to visually inspect the food without opening the door. Additionally, conventional spit assemblies are difficult to disassemble for cleaning purposes. Moreover, conventional ovens do not provide a user-friendly method for removing grease produced during cooking, and additionally fail to provide a user-friendly method and apparatus for cleaning the cooking chamber upon completion of a food preparation sequence.  
      It has thus become desirable to provide a rotisserie oven that overcomes these deficiencies, and that further improves upon existing rotisserie ovens.  
      II.  
      The present invention relates generally to rotisserie ovens, and in particular relates to a method and apparatus for providing an oven that need not be connected to the ductwork of a building, and hence is portable.  
      In most states in the United States, and in most countries, environmental regulations require that rotisserie ovens for cooking meat and poultry food product be located under a hood to vent smoke and moisture produced from the cooking process out of the building. In other locations without this requirement, the need to maintain air quality around the oven to an acceptable level is desired.  
      As a result, the need for a hood over the rotisserie oven requires that the oven be positioned in proximity to a hood that is in communication with the building ductwork, thus limiting the freedom to position the oven in high customer traffic areas. Moreover, rotisserie ovens are in some cases prevented from operating in other buildings, as a hood is expensive, and sometimes impossible, to install in a facility. Installations of such equipment must be U.L. listed in most instances in America and are controlled in other countries by corresponding regulating agencies. These disadvantages have limited the proliferation of rotisserie ovens, thereby reducing or eliminating sales of freshly cooked meat and poultry products (e.g., ribs, duck, turkey, chicken, and the like).  
      What is therefore needed is a cost-effective method and apparatus for mobilizing a rotisserie oven for use in virtually any desirable location without suffering from the prohibitive environmental drawbacks currently experienced.  
     BRIEF SUMMARY OF THE INVENTION  
      I.  
      In accordance with one aspect of the invention, a rotisserie oven is provided for preparing cooked food product from a raw food product. The oven includes a cooking chamber defined by side walls joined at their outer ends to upper and lower walls. The cooking chamber defines at least one open end that is closed by a movable door assembly. A radiating heating system is disposed in the cooking chamber that receives electricity and produces radiating heat. A convection heat system is also disposed in the cooking chamber, and includes A) one ore more heating elements that produce heat in response to electricity, and B) a rotating fan that draws incoming air from the cooking chamber into the convection heat system, forces the air over the heating elements to become heated, and expels the heated air into the cooking chamber. The oven further includes a spit assembly including a pair of rotating discs rotatably attached proximal the side walls and carrying at least one spit configured to support a food product that is heated by the radiating heat source and the convection heat source.  
      II.  
      In accordance with one aspect of the invention, a rotisserie oven is provided for preparing cooked meat and poultry food product. The oven is of the type that includes a cooking chamber defined by side walls joined at their outer ends to upper and lower walls. The cooking chamber defining at least one open end closed by a movable door assembly. A radiating heating system is disposed in the cooking chamber and receives electricity to produce radiating heat. A spit assembly is provided that includes at least one spit configured to rotate within the cooking chamber while carrying a food product to be heated by the radiating heat source. The oven further includes a hood assembly including a housing supported by the cooking chamber. The housing defines a filtration chamber that receives incoming grease-laden air from the cooking chamber and houses at least one filtration member drawing the incoming air therethrough towards a hood outlet. The hood assembly and cooking chamber move together as the rotisserie oven travels from one location to another.  
      The foregoing and other aspects of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration, and not limitation, a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference must therefore be made to the claims herein for interpreting the scope of the invention.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      I.  
       FIG. 1  is a perspective view of a rotisserie oven stacked on top of a warming chamber in accordance with the preferred embodiment;  
       FIG. 2  is a perspective view of a motor that drives the spit assembly illustrated in  FIG. 1 ;  
       FIG. 3  is a perspective view of a coupling that engages the motor illustrated in  FIG. 2 ;  
       FIG. 4  is a perspective view of an inner surface of a support disc that is connected to the coupling illustrated in  FIG. 3 ;  
       FIG. 5  is a perspective view of the outer surface of the support disc illustrated in  FIG. 4 ;  
       FIG. 6A  is a perspective view of a power transfer shaft having a driven end that engages the disc illustrated in  FIGS. 4 and 5 ;  
       FIG. 6B  is a sectional side elevation view of the power transfer shaft illustrated in  FIG. 6A  having one connected end and a second disconnected end;  
       FIG. 7  is a perspective view of a portion of the cooking chamber illustrating a bearing that engages the power transfer shaft illustrated in  FIG. 6 ;  
       FIG. 8  presents a pair of side elevation views of an angled spit that form a part of the preferred embodiment of the invention;  
       FIG. 9  is a perspective view of an assembled spit assembly having a plurality of angled spits and dual pronged spits mounted in accordance with a preferred embodiment of the invention;  
       FIG. 10  is a perspective view of the assembled spit assembly illustrated in  FIG. 9  having a plurality of baskets mounted in accordance with a preferred embodiment of the invention;  
       FIG. 11  is an end elevation view of a drive assembly portion of the spit assembly constructed in accordance with an alternate embodiment of the invention.  
       FIG. 12  is a perspective view of the upper wall of the cooking chamber including a lighting system and radiating heating system;  
       FIG. 13  is a perspective view of the left side wall of the cooking chamber having a convection heating system in combination with a steam cleaning system;  
       FIG. 14  is a perspective view of a fan blade member used in combination with the convection heating system illustrated in  FIGS. 13 ;  
       FIG. 15  is a perspective view of the convection heating system illustrated in  FIG. 13 , but with the cover plate closed;  
       FIG. 16  is a perspective view of the left side of the oven housing including a reservoir constructed in accordance with an alternate embodiment;  
       FIG. 17  is a perspective view of a front door assembly of the oven;  
       FIG. 18  is a perspective view of a waste pan having a drainage valve constructed in accordance with a preferred embodiment of the invention, wherein the valve is in a closed position;  
       FIG. 19  is a schematic sectional side elevation view of a mechanical humidity control module constructed in accordance with an alternate embodiment of the invention;  
      II.  
       FIG. 20  is a front end view of a dedicated filtration hood mounted onto a rotisserie oven;  
       FIG. 21  is a perspective view of a spit assembly housed inside a cooking chamber of the oven illustrated in  FIG. 20 ;  
       FIG. 22  is a perspective view inside the cooking chamber of the oven illustrated in  FIG. 20 ;  
       FIG. 23  is a perspective view of a door assembly providing access to the cooking chamber of  FIG. 22 ;  
       FIG. 24  is a sectional elevation view of the filtration hood illustrated in  FIG. 20  including a pair of filtration members;  
       FIG. 25  is a perspective view of one of the filtration members illustrated in  FIG. 24  engaging an activation switch;  
       FIG. 26  is a sectional side elevation view taken along line  26 - 26  of  FIG. 21  illustrating the other filtration member before engaging an activation switch;  
       FIG. 27  is a schematic sectional side elevation view of the filtration member illustrated in  FIG. 26  after engaging the activation switch;  
       FIG. 28  is a perspective view of the hood illustrated in  FIG. 20  including a removable latch assembly engaging the front door of the rotisserie oven;  
       FIG. 29  is a sectional side elevation view of the latch assembly taken along the line  29 - 29  of  FIG. 28 ;  
       FIG. 30  is a sectional side elevation view similar to  FIG. 29 , but with the front door slightly ajar and locked with respect to further opening by the latch assembly; and  
       FIG. 31  is a sectional side elevation view similar to  FIG. 30 , but with the latch assembly removed from engagement with the front door assembly, thereby permitting the door assembly to fully open. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      I.  
      Referring initially to  FIG. 1 , a rotisserie oven  40  includes an outer housing  41  having upper and lower walls  42  and  44 , respectively, opposing left and right side walls  46  and  48 , respectively, and opposing front and rear walls  50  and  52  (shown in  FIG. 2 ), respectively. A cooking chamber  58  is defined by upper and lower walls  42  and  44 , right side wall  48 , and a left side wall  64  (See  FIG. 14 ).  
      Wall  64  is spaced from wall  46  that together define the lateral boundaries of a cabinet  68  that contains control components (e.g., a microprocessor, not shown, or other suitable controller) of oven  40 . In particular, cabinet  68  houses a control assembly (not shown) that controls various aspects of the oven  40 , such as temperature control, cooking sequences, and cleaning functions as is described in more detail below. Cabinet  68  further houses a motor  74  (See  FIG. 2 ) that drives a spit assembly  82 . Oven operation is controlled by an operator via a set of user controls and outputs  77  that are disposed on the front wall  50  of cabinet  68 .  
      A front door assembly  54  is connected to the front wall  50 , and a rear door assembly  56  is carried by the rear wall  52  that can both be opened and closed to provide access to cooking chamber  58 . Front door assembly  54  includes a window assembly  55  that provides visible access to the cooking chamber  58 , as will be described in more detail below. Rear door assembly  56  is preferably constructed in the manner described with respect to front door assembly  54 . Oven  40  thus has a pass-through design as described in U.S. Pat. No. 6,608,288, and thus may further be used in accordance with the methods described therein.  
      The rotisserie oven  40  can be mounted on top of a warming chamber  67  including a housing  70  of generally the same size and shape as housing  41 , and an internal warming chamber (not shown) of generally the same size and shape of cooking chamber  58 . Advantageously, the rotisserie oven  40  and warming chamber  67  may be stacked on top of each other. Ovens  40  and  72  are modular, such that oven  40  has rotisserie and/or convection heating components installed and warming chamber  72  may have a conductive heating systems installed that are configured to maintain the temperature of the food product that was prepared in the rotisserie oven. Oven  40  can alternatively be supported on, for instance, a kitchen floor directly via any suitable conventional a support assembly.  
      Spit assembly  82  includes a plurality of spits (collectively identified as  78 ) that span between side walls  46  and  48  of the cooking chamber  58 . Specifically, spits  78  span between a pair of support discs  106  (one shown in  FIG. 1 ) and are suitable for retaining meat product such as chicken, turkey, duck, and the like. Discs  106  are rotated under power supplied by motor  74  to correspondingly rotate the meat product with respect to a heat source.  
      Referring now to  FIG. 2 , motor  74  is mounted within cabinet, and includes an outwardly extending rotating output shaft  84 . Shaft  84  extends through left side wall  64  of the cooking chamber  58 . A groove  86  extends axially into the outer end of shaft  84 , bifurcating the shaft to define a pair of engaging members  87 . Motor  74  operates under electric power to rotate output shaft  86 , including members  87 . The speed of motor rotation can be set by the user via controls  77 .  
      Referring to  FIG. 3 , a coupling  88  is provided for attachment to output shaft  84 . Coupling  88  includes a cylindrical mounting plate  90  that includes a plurality (preferably three spaced 120° apart) apertures  104  extending axially therethrough. An annular shaft  92  extends outwardly from mounting plate  90  for connection to motor  74 . A pair of aligned apertures  94  is formed through the outer end  96  of shaft  92 . A dowel  102  having a thickness less than that of groove  86  is inserted into apertures  94 . The inner diameter of shaft  92  is slightly greater than the outer diameter of output shaft  84  such that the output shaft  84  is received by shaft  92 . When properly inserted, dowel  102  is inserted into groove  86  to interlock the coupling  88  with the output shaft  84 . Accordingly, coupling  88  rotates along with output shaft  84  during operation. If desired, a second pair of apertures (not shown) could extend through shaft  92  spaced from apertures  94  that receive a second dowel to further engage members  87  of output shaft  84 .  
      Referring now to  FIGS. 4 and 5 , each support disc  106  includes an annular outer ring portion  108  and a pair of perpendicular ribs  110  that are connected at their outer ends to ring portion  108 . Ribs  110  intersect at a centrally disposed hub  112 , which is centrally disposed relative to disc  106 . A pair of discs  106  are provided in accordance with the preferred embodiment, one of which being disposed at the drive end of the spit assembly  82 , the other of which being disposed at the driven end of assembly  82 .  
       FIG. 4  illustrates an inner, coupling-engaging, face  100  of disc  106 . In particular, coupling  88  is attached to surface  100  of hub  112  via screws, projections extending from hub  112 , or the like, that extend through apertures  104 . Accordingly, once coupling  88  is attached to disc  106 , dowel  102  faces outwardly and can engage motor  74  in the manner described above. Referring also to  FIG. 7 , a roller bearing  136  extends into the cooking chamber  58  from right side wall  48  in linear alignment with output shaft  84 . Bearing  136  includes a shaft  89  defining a groove  91  in the manner with respect to output shaft  84 . Accordingly, the second disc  106  is rotatably supported within chamber  58  via an attachment with bearing  136  in the manner described above with respect to coupling  88 .  
       FIG. 7  further illustrates a temperature sensor  79  that is mounted onto the right side wall  48  for sensing the temperature in cooking chamber  58 . The temperature can displayed at the user outputs  77 . An electrical lead  221  is connected to the oven control system, extends into cooking chamber  58  from upper wall  42 , and is connected at its outer end to a temperature probe ( FIG. 12 ) as will be described in more detail below.  
      Referring now to  FIG. 5  the outer, shaft-engaging, face  101  of each disc  106  is disposed opposite inner surface  100 . A generally cylindrical connector member  114  extends outwardly from outer face  101  at hub  112 . The outer end  118  of connector  114  is semi-cylindrical defines a flat engagement surface  116 . An opening  117  extends into surface  116  in a direction perpendicular to surface  116 .  
      Referring now to  FIGS. 6A and 6B , a power transfer shaft  120  is provided that is connected between discs  106 . Shaft includes a first end  122  disposed proximal the motor, and a second end  124  opposite the first end  122  that is disposed proximal the right side wall  48  of cooking chamber  58 . As illustrated in  FIG. 6B , end  122  is illustrated as being connected while end  124  is illustrated as being disconnected to demonstrate operation of the components of shaft  120 .  
      Each end  122  and  124  includes a semi-cylindrical connector  126  presenting a flange  133  defining a diameter greater than the diameter of shaft  120 . Connector  126  further presents a flat engagement surface  128  downstream from flange  133 . A pin  129  extends perpendicularly out from engagement surface  128  sized slightly less than the diameter of opening  117  formed in surface  116  of support disc  106 . Engagement surface  128  is thus configured to mate with engagement surface  116  of support disc  106  as pin  129  is inserted into opening  117 , thereby causing discs  106  to interlock with shaft  120  with respect to rotation.  
      A movable collar  135  is provided having an inner diameter sized to correspond to the diameter of shaft  120 , and a counterbore  131  sized to correspond to the outer surface of the cylindrical joint formed between connector members  126  and  114 . A washer  134  is provided at each end  122  and  124 , and is disposed inwardly with respect to collar  135 . During operation, once connector  126  is fastened to coupling  114 , collar is slid over the resulting cylindrical joint to secure the connector  126  to the coupling  114 . Flange  133  provides a stop for collar  135 , thus ensuring that collar is properly positioned. When collar is fully engaged, a recess  132  circumferentially formed in shaft  120  is exposed. Washer  134  is slid into engagement with recess  132  to prevent connector  126  from sliding out of engagement with the joint during operation.  
      Referring also to  FIGS. 9 and 10  in particular, spit assembly  82  is assembled by mounting couplings  88  are first mounted onto hubs  112  of discs  106  as described above. The shaft portions  92  of couplings  88  are then connected to motor  74  and bearing  136 , respectively. Shaft  120  is then installed, such that ends  122  and  124  are connected to the shaft connectors  114  located on support discs  106 . Accordingly, when motor  74  is operated, output shaft  84  rotates the connected disc  106  which, in turn rotates the power transfer shaft  120  which then causes rotation of the opposing disc  106  as permitted by bearing  136 . The spit assembly  82  may be disassembled by reversing the assembly process, for instance when it is desired to clean the cooking chamber  58 .  
      Referring now also to  FIG. 8 , the assembled spit assembly  82  is illustrated having various spits  78  connected between the rotating discs  106 . In particular, a first angled spit  138  includes a pair of elongated axially extending flat walls  140  that join at an axially extending apex  142  to assume the general shape of an elongated bracket. Walls  140  define a pointed end  141  that is disposed at one end of spit  138 . A mounting pin  144  extends outwardly from the pointed end  142 . The other end of the spit  138  includes a pair of mounting pins  144  extending outwardly (one from each wall  140 ).  
      Referring to  FIG. 9  in particular, a second dual-prong spit  145  includes a pair of cylindrical skewer rods  146  that are joined by a rib  150  at one end. Mounting pins  144  (not shown) extend outwardly from each end of each rod  146 . The mounting pins disposed remote from rib  150  may be pointed to assist in piercing uncooked food product. The mounting pins of spit  146  are spaced the same distance apart as mounting pins  144  of spit  138 .  
      Referring now to  FIG. 10 , a third spit is a basket  149  that includes an axially elongated base  150  integrally connected to opposing side walls  152  that are angled outwardly with respect to the base. A pair of opposing end walls  154  closes each basket  149 . Food product (for instance, of the type that is not suitable to be easily skewered) can thus sit in baskets  149  during operation. A slot or plurality of slots (not shown) extends between the base  150  and side walls  152  to assist in the drainage of grease that is produced during the preparation of the food product. A mounting flange  156  extends upward from each end wall  154 , and supports a mounting pin  144  that extends outwardly from the flange  156 . Mounting pins  144  enable rotation of the corresponding spit  78 . It should be appreciated that any of spits  78 ,  138 , and  149  can be interchangeably attached to support discs  106  as desired to accommodate a given food product to be cooked. In this regard, it should be appreciated that “spit” as used herein refers to any apparatus configured to connect between discs  106  that is suitable to carry food product during a food preparation sequence.  
      Discs  106  define a plurality of spit mounting locations  158  circumferentially spaced about outer ring portion  108 . Each mounting location  158  includes two pairs of apertures  160  designed to receive mounting pins  144 . In particular, a first pair of apertures  160  includes first and second radially aligned apertures, respectively, while a second pair of apertures  160  includes tangentially aligned apertures.  
      The tangentially aligned apertures  160  are configured to receive mounting pins  144  of the dual-pronged ends of spits  138  and  146 . Radially aligned apertures  160  are configured to receive mounting pins  144  of the single-pronged ends of spits  138  and  149 . Advantageously, for larger food product, spit  138  may be orientated with the single mounting pin  144  of the pointed end  142  in the radially inner aperture  160  such that apex  144  points inwardly to position the food product away from the radiating heat elements, as will be described below. Alternatively, for smaller food product, mounting pin  144  of the pointed end  142  may be positioned in the radially inner aperture  162  such spit  138  is inverted and apex  142  faces outwardly, thereby positioning the food product closer to the radiating heat elements. Sufficient clearance exists such that one end of the spits  78  may be translated towards one of the discs  106  such that the mounting pin(s)  144  at the opposite end are removed from the corresponding disc  106 . Accordingly, spits may be easily attached to and removed from assembly  82 .  
      Referring to  FIG. 11 , the drive portion of a spit assembly  270  is illustrated in accordance with an alternate embodiment. Spit assembly  270  includes all components described above with respect to spit assembly  82  (unless otherwise mentioned), except assembly  270  does not require power transfer shaft  120  to extend through cooking chamber  54 . As a result, additional space is preserved for food product that is to be prepared.  
      Instead, while discs  106  are coupled to output shaft  84  and bearing  136 , respectively, in the manner described above, output shaft  84  includes a pulley  274  disposed outside of chamber  58 . Pulley  274  supports a drive belt  278  that extends down to a pulley  280  mounted to the left end of a power transfer shaft  282  extending beneath lower wall  44 . Pulleys  274  and  280  are vertically aligned. A second set of pulleys includes a pulley  284  connected to the right end of shaft  282  that is in vertical alignment with a pulley  285  extending through housing wall  48  and rotatably coupled to bearing  136  and, hence, the corresponding support disc  106 . A driven belt  286  is connected between pulleys  284  and  285  such that rotation of shaft  282  causes disc  106  carried by the right side wall to rotate. Accordingly, both discs  106  (and remaining portions of spit assembly  270 ) are caused to rotate upon rotation of motor output shaft  84  without the need for a shaft to span between the discs  106  inside the cooking chamber  58 .  
      The various systems of oven  40  will now be described with initial reference to  FIGS. 13-15 . In particular, a rectangular recess  173  is formed in side wall  64  that carries a convection heating system  172  and steam-producing cleaning system  174 . In particular, heating system  172  includes a standard resistive coil  180  in the form of a loop that is connected to controller  77  and produces heat in response to an electrical input. A fan  182  is disposed inside the loop formed by the coil  180 , and includes a circular plate  183  supporting a plurality of circumferential fan blades  184  that rotate about a hub  186  to draw air into heating system  172  from cooking chamber  58 .  
      A cover  188  is hingedly mounted on the left side wall  64  and can be closed to the position illustrated in  FIG. 15  to house convection heating system  172 . A plurality of grooves  190  extend through the cover  188  and are substantially aligned with fan  182  to provide an air intake for the fan  182 . Cover  188  does not span laterally the entire distance of recess  173  such that vertically extending gaps  192  are defined between cover  188  and left side wall  64  on both lateral sides of fan  182  to provide an air outlet for heated air. Horizontal vents  193  are also formed in cover  188  to provide additional air outlets. Accordingly, during operation, fan blades  184  rotate to draw air into the fan  182  via intake grooves  190 . The air is expelled radially outwardly by the fan blades  184 , thereby forcing the air to flow across resistive coil  180  before being expelled into the cooking chamber  58  via air outlet gaps  192  and  193  to heat the food product.  
      With continuing reference to  FIGS. 13-15 , the present invention recognizes the difficulties associated in removing grease produced during a cooking sequence from the walls of the cooking chamber  58 . Accordingly, a steam producing assembly  174  is provided that introduces steam into the cooking chamber  58  once a user initiates a cleaning cycle via user controls  77 . In order to ensure that steam is not introduced into chamber  58  during the cooking cycle, oven  40  will prevent steam from being produced until the temperature in the cooking chamber  58  is below a predetermined threshold indicating the food product is no longer being cooked.  
      Steam assembly  174  includes a conduit  213  carrying water from a conventional water source (not shown). Conduit extends through left side wall  64 , and preferably through recessed region  173 . Conduit  213  defines a distal outlet end  217  that disposed at hub  186  of fan  182 . In particular, outlet end  217  is disposed within a water distributor  219  that surrounds hub  186 . Distributor  219  includes a plurality of side walls  215  that define an open outer end  214  that receives water from conduit  213 . A slot  216  extends through the interface between adjacent side walls  215 . Accordingly, water entering the distributor  219  via conduit  213  is “slung” through slots  216  as fan  182  rotates. The expelled water then contacts the heating coil  180  to produce steam that is emitted into the cooking chamber  58  via gaps  192  and  193  under forces from fan blades  184 . It has been found that the introduction of steam into a chamber increases the efficiency of grease removal. During operation, cover  188  can be closed over conduit  213  as illustrated in  FIG. 15 .  
      As discussed above, conduit  213  can receive water from a waterline (e.g., faucet). Alternatively, referring now to  FIG. 16 , conduit  213  can receive water from an internal tank  43  that is either located external to the oven  40 , or mounted within cabinet  68 . Tank  43  can be filled as needed when chamber  58  is to be steam cleaned. In particular, a hatch  47  is formed in left side wall  46  of housing  41  that may be opened in the direction of Arrow A. Water may be delivered into the hatch  47  to fill internal tank  43  that is connected to outlet  213 . In this embodiment, water can be forced through conduit  213  via a pump (not shown) or, alternatively, conduit  43  can be connected to tank  43  in a desired manner to produce water pressure from the water stored in tank, thereby forcing water through conduit and into distributor  219 .  
      Referring now to  FIG. 12 , oven  40  further includes a radiating heat system  176  that deliver radiating heat to food product carried by spit assembly  82 . Radiating heat system  176  is elongated in a direction between side walls  48  and  64  and is centrally disposed above spit assembly  82 . The cooking chamber  58  thus advantageously incorporates a convection heat source  172  that is used to cook raw food product along with a radiation heat system  176  that browns the food being prepared.  
      Radiation heat system  176  includes a plurality of rectangular ceramic discs  177  having grooves that at least partially enclose traditional resistive coils. In particular, the bottom of the coil (when positioned as installed in the cooking chamber  58 ) is essentially coated with a ceramic material which has been found to emit infrared heat that is less scattered compared to coils that are not embedded in ceramic. The food product is thus browned more uniformly than conventionally achieved. The coils are connected via electrical leads to the control, and emit heat upon an electrical input. As described above, angled spit  138  may be positioned in the discs  106  in a desired orientation depending on the desired distance between heat system  176  and the outer surface of the food product.  
      Accordingly, heat is produced in response to the supply of electrical power to the coils, which is controlled via user inputs  77 , in order to prepare food product rotating with spit assembly  82 . Ceramic heaters  177  are preferably of the type commercially available from OGDEN Corp, located in Arlington Heights, Ill. or Chromalox, Inc. located in Pittsburgh, Pa.  
      The present invention recognizes that the heating systems  172  and  176  are rated commercially for a predetermined wattage output, as it is desirable to ensure the consistency of the food preparation process. Because the oven  40  may be used worldwide in electrical receptacles that deliver electrical currents having varying input voltage levels, the control  77  senses the input voltage and delivers electrical pulses to the heating systems  172  and  176  to regulate the effective voltage that is applied to the heating systems. Increased input voltage levels will cause the controller to reduce the pulse frequency, and vice versa. Accordingly, a consistent desired wattage output of the heating systems is advantageously maintained. The pulses may either be delivered independently to each heating system  172  or  176 . Alternatively, a combined pulse may be sent to both heating systems  172  and  176 . Furthermore, controller  77  is connected to motor  74  of spit assembly  82  via a DC motor that pulses power to motor  74  in response to a user input on the user controls  77 , thus enabling the user to regulate the speed of spit rotation.  
      A pair of lighting systems  178  are both disposed in the upper wall  42  of cooking chamber  58  to illuminate cooking chamber  58  on demand. Lighting systems are positioned such that radiating heat system  176  is centrally disposed between the pair of lighting systems  178 . Lighting systems  178  extend between side walls  64  and  48  and parallel to radiating heat system  176 . Each lighting system  178  is disposed in a rectangular recess  194  that is formed in the upper wall  60  of cooking chamber  58 . A pair of opposing sockets  205  extends into the recess  194 . Advantageously, sockets  205  receive standard Edison Socket style of light bulbs  179  as well as more expensive Halogen bulbs. The recess  194  is closed at its bottom via a glass cover  206  that is hingedly connected to the lower edge on of the recess walls, and fastened to an opposing side wall via a latch  208 . Accordingly, the glass cover  206  may be opened and closed as desired when bulbs  179  are to be replaced. Lighting systems  178  can be activated upon opening either door  54  or  56 , or alternatively can be controlled via user inputs  77 .  
      Advantageously, the bulbs  179  are disposed above the radiation heat source  176 , and are thus not exposed to direct infrared heating. Furthermore, the recess  194  and glass cover  206  shield the bulbs  179  from the convection heat source  172 . Accordingly, the bulbs  179  are not as susceptible to breakage as conventional designs whose bulbs are placed in the cooking chamber in the direct path of heat from the heat source. Furthermore, when bulbs of conventional ovens break during a food preparation sequence, the bulb particles become scattered on the food, which must therefore be discarded. In accordance with the preferred embodiment, if bulbs  179  were to somehow break, cover  206  would prevent the remnants from entering the cooking chamber  58 , thereby preserving the food being prepared.  
      Referring now to  FIG. 17 , front door assembly  54  includes an outer glass pane  220  that is bowed along a vertical axis away from cooking chamber  58 . A door handle  222  (See  FIG. 1 ) is connected to one end of the outer surface of glass member  220 . Pane  220  is hingedly connected to oven via a vertical door frame member  224 , and is further supported at its end opposite the hinged end via a second vertical door frame member  229 . A second, flat, glass pane  232  is provided that is hingedly connected to door frame member  224 , and is inwardly disposed with respect to pane  220 . A gap  233  extends between panes  220  and  232  for heat dissipation during use. Glass panes  220  and  232  are permitted to rotate relative to chamber  48  and to each other, however panes  220  and  232  are generally coupled for rotation together, and-are primarily decoupled when cleaning becomes necessary.  
      A plurality of magnets  225  is disposed in door frame  229 . The magnets  225  are sensed at the housing  41  and communicated to the oven controller to automatically determine when the door  54  assembly is open. The magnets  225  further bond the door assembly  54  to the housing  41 . A strip of silicon rubber or like sealant (not shown) can be applied to the front wall  50  of housing  41  around the opening to cooking chamber  58  in order to form a tight seal with the door assembly  54  to prevent leakage of flavored gasses from the cooking chamber  58 .  
      As described above, insulated electrical wiring  221  is mounted at upper surface  42  within cooking chamber  58 , and extends down towards door assembly. A temperature probe  234  is connected to the distal end of wiring  221  and is supported by a bracket  237  mounted onto the inner surface of pane  232 . Accordingly, when door assembly  54  is opened, a user can insert probe  234  into the food product being cooked to measure the temperature of the food product, which can be displayed at user output  77 . In accordance with the preferred embodiment, the oven controller is programmed to automatically measure and display the temperature of the sensor  79  to display the temperature inside cooking chamber  58  until the door assembly  54  is opened, at which point the control will display the temperature of probe  234 . Of course, the user may change these default settings if desired.  
      As noted above, rear door assembly  56  can be constructed in the manner described with reference to front door assembly  54 .  
      Referring now to  FIG. 18 , a drain pan  242  is be disposed above the base  62  of cooking chamber  58 , and is angled downward along a direction into chamber  48  from both door assemblies  54  and  56 . A groove (not shown) can extend axially at the apex of the drain pan  242  that enables grease to drain from the drain pan  242 . A waste pan  244  is disposed between base  62  and the drain pan  242 , and provides a receptacle  245  that receives grease and other cooking byproducts from the groove in drain pan  242 . Waste pan  244  may be easily removed from and inserted into the void between base  62  and drain pan  242 . Alternatively, waste pan  244  could include a trough at its base that in connected to a conduit which, in turn, connects to a proper grease disposal site.  
      A valve  246  is disposed in the front surface  248  of the waste pan  244  at a location towards the base. The valve  246  provides a conduit that extends outwardly from the waste pan  244  and upwardly when it is desired to store the contents in the waste pan. Once it is desired to drain the waste pan, the valve  246  is rotated downwardly in the direction of Arrow B, thereby enabling fluid to flow through the valve  246  and into a conduit or a portable receptacle (not shown) for the removal of grease. The base of waste pan  244  may be angled downward towards valve  246  to force fluid to flow into the valve. Alternatively, oven  40  may include a grease removal system of the type described in U.S. Provisional Patent Application Ser. No. 60/464,681, and farther files as a U.S. utility patent application Apr. 22, 2004 entitled “Grease Collection System for Oven”, the disclosure of which is hereby incorporated by references.  
      Referring now to  FIG. 19 , oven  40  may include a humidity regulating system  250  that reduces the humidity level inside cooking chamber  58  in order to reduce the accumulation of condensation on door assemblies  54  and  56 . Humidity regulating system includes a vapor intake channel  252  extending through the upper end of left side wall  64  of cooking chamber  58 . Intake channel  252  is connected to an adapter  259  disposed in cabinet  68  which, in turn, delivers incoming humid air  265  produced during cooking along the direction of Arrow C to a conduit  261  that flows into a condensing box  253 . Condensing box  253  defines an internal reservoir  263  that receives air from conduit  261 .  
      A baffle plate  257  extends down from the upper wall of condensing box  253 , and separates reservoir  263  into an intake section  267  and a vacuum section  269 . Baffle plate  257  does not extend entirely through to the bottom wall  271  of condensing box  253 . Accordingly, vacuum section  269  is in fluid communication with intake section  267 . Reservoir  263  defines a drain  255  extending through bottom wall  271 , which is sloped towards drain  255  to directed condensed liquid into drain  255 . Drain  255  is connected an outlet tube  258  that extends through side wall  64  and delivers fluid to drain pan  242  or, alternatively, directly into waste pan  244 .  
      During operation, incoming air  265  flows into intake channel  252  and eventually into condensing box  253 . The temperature of condensing box may be regulated using any conventional refrigeration or cooling system in order to ensure that the incoming steam condenses into a liquid inside condensing box  253 . A blower  260  may be mounted to vacuum section  269  in order to draw air from the cooking chamber  58  into vacuum section  267 . Advantageously, baffle plate  257  prevents the incoming air  265  from flowing directly into blower  260  prior to moisture removal. Instead, the moisture in the incoming air  265  condenses as the air travels down through intake section  267  before traveling up through vacuum section  269 . Air  265  can also condense while traveling up in the vacuum section  269  prior to being expelled from the oven by blower  260 . The condensed fluid flows down into drain  258 , through conduit  258 , and ultimately into drain pan  242  or waste pan. The oven control can also sense the humidity level inside cooking chamber  58  and adjust the speed of blower  60  accordingly in order to maintain a desired humidity level. The reduced humidity level reduces condensation from accumulating on doors  54  and  56 , and hence provides the user with improved visible access to the food product being prepared.  
      In accordance with an alternative embodiment, blower  260  can be eliminated, and inlet  252  can be sized sufficiently large to ensure that steam produced during cooking will naturally flow into condensing box  253 . Furthermore, inlet  252  may be sloped upwards so as to enable a greater amount of steam (which flows upwards in chamber  58 ) to enter the humidity control module  250 .  
      II.  
      Referring initially to  FIGS. 20-22 , a rotisserie oven  320  includes an outer housing  322  having upper and lower walls  324  and  326 , respectively, opposing left and right side walls  328  and  330 , respectively, and an opposing front wall  332  and rear wall (not shown). A cooking chamber  334  is defined inside oven  320  by upper and lower walls  324  and  326 , right side wall  330 , and a left side wall  336  spaced apart from, and parallel to, left side wall  328 . A front door assembly  338  is connected to the front wall  332 , and a rear door assembly  340  is carried by the rear wall that can both be opened and closed to provide access to cooking chamber  334 . Each door assembly  338  and  340  is at least partially transparent to provide visual access to cooking chamber  334  when closed. Oven  320  is preferably supported by a plurality of legs  342  extending downwardly from each corner of lower wall  326  that engage the kitchen floor  344 , or like support surface, via casters  346  to enable oven portability.  
      An oven cabinet  348  is contained in the void defined between side walls  328  and  336 , and upper and lower walls  324  and  326  that houses an oven control  407  (e.g., a microprocessor or other suitable control module), as illustrated in  FIG. 24 . A plurality of user-actuated inputs that control oven operation and outputs that display information related to oven operation (collectively identified as  350 ) are carried by front wall  332  at cabinet  348 .  
      Cooking chamber  334  houses a spit assembly  352  including a plurality of spits (collectively identified as  354 ) connected between side walls  330  and  336 . Specifically, a drive shaft  356  is connected between the hubs  358  of a pair of generally annular support discs  360  to rotatably fix each disc  360  with respect to the other. Spits  354  are connected between discs  360  and are suitable for carrying meat and poultry product such as chicken, turkey, duck, and the like, in the usual manner. Each disc  360  includes a connector  362  at the outer end of each hub  358 , one of which engaging the output shaft of a drive motor (not shown) disposed in cabinet  348  and extending through side wall  336 , and the other of which engaging a bearing (not shown) mounted onto side wall  330 . Discs  360  and spits  354  are thus rotated in response to rotation of the motor output shaft.  
      Oven  320  produces heat within cooking chamber  334  using a radiation heat system  364  carried by upper wall  324 , and furthermore by optionally using a convection heating system  366  carried by side wall  336 .  
      Radiating heat system  364  delivers radiating heat to food product carried by spit assembly  352 . Radiating heat system  364  is elongated in a direction between side walls  330  and  336  and is centrally disposed above spit assembly  352 , and includes a plurality of rectangular ceramic disks  368  that are grooved to surround traditional resistive coils. In particular, the bottom of the coil (when positioned as installed in the cooking chamber  334 ) is essentially coated with a ceramic material which has been found to emit infrared heat that is less scattered compared to coils that are not embedded in ceramic. The food product is thus browned more uniformly than conventionally achieved. The coils are connected via electrical leads to the control, and emit heat upon an electrical input.  
      Accordingly, heat is produced in response to the supply of electrical power to the coils, which is controlled via user inputs  350 , in order to prepare food product rotating with spit assembly  352 . Ceramic heaters  368  are preferably of the type commercially available from OGDEN Corp, located in Arlington Heights, Ill. or Chromalox, Inc. located in Pittsburgh, Pa.  
      Convection heating system  66  includes one or more standard resistive coils and fan positioned in a void (not shown) behind a perforated grill  370 . The coils are of the conventional type that produces heat in response to an electrical input. During operation, the fan blades rotate to draw air into the void via grill  370 , and expel the incoming air outwardly across the resistive coils to heat the air. The heated air is then directed into the oven chamber  334  through peripheral openings (not shown) in grill  370  to cook the food product carried by spit assembly  352 .  
      The cooking chamber  334  thus advantageously incorporates a radiation heat system  364  that cooks and browns raw food product carried by spit assembly  328 , and furthermore can include a convection heat source  366  to assist in cooking the food product.  
      A pair of lighting systems  372  is both disposed in the upper wall  342  of cooking chamber  334  to illuminate cooking chamber  334  on demand. Lighting systems  372  are positioned such that radiating heat system  364  is centrally disposed between the pair of lighting assemblies  372 . Lighting assemblies  372  extend between side walls  336  and  330  and parallel to radiating heat system  364 . Each lighting assembly  372  is disposed in a rectangular recess  374  that is formed in the upper wall  324  of cooking chamber  334 . A pair of opposing sockets  376  extends into the recess  374 . Advantageously, sockets  376  receive standard Edison Socket style of light bulbs  378  as well as more expensive Halogen bulbs. The recess  374  is closed at its bottom via a glass cover  380  that is hingedly connected to the lower edge on of the recess walls, and fastened to an opposing side wall via a latch  382 . Accordingly, the glass cover  380  may be opened and closed as desired when bulbs  378  are to be replaced. Lighting assemblies  372  can be activated automatically upon opening either door assembly, or alternatively can be controlled via user inputs  350 .  
      Advantageously, the bulbs  378  are disposed above the radiation heat source  364 , and are thus not exposed to direct infrared heating. Furthermore, the recess  374  and glass cover  380  shield the bulbs  378  from the convection heat source  366 . Accordingly, the bulbs  378  are not as susceptible to breakage as conventional designs whose bulbs are placed in the cooking chamber in the direct path of heat from the heat source. Furthermore, when bulbs of conventional ovens break during a food preparation sequence, the bulb particles become scattered on the food, which must therefore be discarded. In accordance with the preferred embodiment, if bulbs  378  were to somehow break, cover  380  would prevent the remnants from entering the cooking chamber  334 , thereby preserving the food being prepared.  
      Referring now to  FIG. 23 , front door assembly  338  includes an outer glass pane  84  that is bowed away from cooking chamber  334  with respect to a vertical axis. A pair of vertical frame members  386  extends along the outer edges of glass pane  384 . Pane  384  is hingedly connected to oven via vertical frame member  388 , and further includes upper and lower horizontal frame members  389  and  391 , respectively. A second, flat, glass pane  390  is provided that is hingedly connected to door frame member  388 , and is inwardly disposed with respect to pane  384 . A gap  392  is thus disposed between panes  384  and  390 , and provides heat dissipation during use such that the bowed glass pane  384  is cool to the touch during use. A door handle  394  (See  FIG. 20 ) is connected to the outer surface of vertical frame member  386 . Glass panes  384  and  390  are permitted to rotate relative to chamber  334  and to each other, however panes  384  and  390  are generally coupled for rotation together, and are primarily decoupled when cleaning becomes necessary.  
      A plurality of magnets  396  is disposed in door frame  386 , and in horizontal frame members  389  and  391 . The magnets  396  engage front wall  332  to bond the door assembly  338  to housing  322 , and can be sensed by corresponding magnets or the like that communicate with oven controller  407  to automatically determine when the door assembly  338  is open. In accordance with an alternate embodiment, only those magnets  396  carried by inner pane  390  are sensed. A strip of silicon rubber or like sealant  398  (see  FIGS. 29-31 ) can be applied to inner pane  390 , or the front wall  332  of housing  322  around the opening to cooking chamber  334 , in order to form a tight seal with the door assembly  338  to prevent leakage of flavored gasses from the cooking chamber  334  when door assembly  338  is closed.  
      Rear door assembly  340  can be supported by the rear wall of oven  320  in the manner described above with respect to front door assembly  338 . Oven  320  thus has a pass-through design as described in U.S. Pat. No. 6,608,288, and thus may further be used in accordance with the methods described therein.  
      Oven  320  is preferably of the type disclosed in a co-pending U.S. patent application Ser. No. 10/428,796 filed May 2, 2003 and the oven described in part I of this application, the disclosures of each which are hereby incorporated by reference as if set forth in their entirety herein. It should be appreciated, however, that the principles of the present invention are applicable to any rotisserie oven.  
      Referring now to  FIGS. 20 and 24 , oven  40  includes a dedicated oven filtration hood  400  is mounted onto the upper surface of upper wall  342  that is configured to remove impurities from air exhausted from cooling chamber  334 . Advantageously, hood  400  permits oven  340  to be positioned in virtually any desirable location without polluting the surrounding air with gasses produced during cooking.  
      Filtration hood  400  is generally defined by a housing  402  including upper and lower walls  404  and  406 , respectively, opposing left and right side walls  408  and  410 , respectively, and front and rear walls  409  and  411 , respectively. Hood  410  includes a cabinet  413  defined by side wall  408 , lower wall  406 , upper wall  404 , and a side wall  405  spaced apart from, and extending parallel to, side wall  408 . Cabinet  413  can enclose controller  407  (schematically illustrated) which maybe the same as, or different from the oven controller, and operates a stored program to control the various functions of hood  410  that will be described below. If operation of oven  320  and operation of hood  400  are controlled by two separate controllers, it would be desirable that the two controllers communicate to provide coordinated operation of oven  320  and hood  400 , as will become apparent from the description below. Front wall  409  of cabinet  413  contains a plurality of user-actuated inputs and outputs (collectively identified as  415 ) in communication with controller  407 .  
      Hood  410  further encloses a filtration chamber  412  defined by lower wall  406 , an upper wall  414  that extends parallel to, and is spaced from, wall  404 , a left side wall  416  that extends parallel to, and is spaced from, wall  408 , and a right side wall  418  that extends parallel to, and is spaced from, wall  410 . Lower wall  406  of filtration chamber  412  defines a plurality of vents  420  extending therethrough and into cooking chamber  334  such that, during a cooking operation, gasses vented from cooking chamber  334  flow substantially vertically upwards into filtration chamber  412  along the direction of Arrows A. A sensor  419  can be coupled to controller  107  to measure the rate that grease-laden air flows from cooking chamber  334  into filtration chamber  412 .  
      Referring also to  FIG. 25 , a first filter  422  is supported inside filtration chamber  412  at an angle, and is located downstream of vents  420  with respect to airflow. Filter  422  is a baffle filter including a plurality of conventional metallic grates  424  that condense grease fumes and steam vapor when the air is brought into contact with the plates along the general direction of Arrows B. A drain  426  extends through lower wall  406  of filtration chamber for the drainage of moisture that is removed from the incoming air passing through filter  422 . If desired, wall  406  can be sloped towards drain  426  to facilitate liquid removal.  
      Filter  422  is supported at its lower end by a lower bracket  428  extending up from lower wall  406 . Bracket  428  includes an outer surface  430  that is angled with respect to lower wall  406  that directly supports the lower surface of filter  422 . A plurality of flanges  431  extends out from surface  430  at a perpendicular angle, and supports the lower end of the upstream side wall of filter  422 . An upper bracket  432  is attached to upper wall  414 , and presents a surface  434  that is angled with respect to upper wall  414 , and extends substantially perpendicular with respect to surface  430 . Bracket surface  434  provides a seat for the upper end of the upstream side wall of filter  422 . Brackets  428  and  432  extend between front wall  409  and rear wall  411  of chamber  412 . Filter  422  is thus advantageously removably supported inside chamber  412  by brackets  428  and  432 . It may be desirable to remove filter for cleaning purposes.  
      Referring now also to  FIG. 26 , a second filter  436  is disposed downstream from first filter  422 , and extends perpendicularly between upper and lower walls  414  and  406 . During operation, air passing through baffle filter  422  travels along the direction of Arrows C to second filter  436 . Filter  436  includes an outer frame  437  that defines an open middle portion  439  containing any suitable filtration material  441 , such as charcoal in accordance with the preferred embodiment. Air travels through filter  436  along the direction of Arrows D, and the filtration material removes impurities from the dehumidified air.  
      Filter  436  is supported in chamber  412  by a pair of upper brackets  438  is mounted onto upper wall  414 , each of which defining an inner vertical support surface  440 . Support surfaces  440  are spaced apart to define a gap substantially equal in size to (or slightly greater than) the thickness of filter  436 . A lower bracket  442  is mounted onto lower wall  406 , and defines a pair of vertical flanges  444  extending up from a horizontal support surface  443 . Flanges  444  define therebetween a gap substantially equal in size to the gap defined by upper brackets  438 . Brackets  438  and  442  extend between front wall  409  and rear wall  411 . Filter  436  is thus advantageously removably supported inside chamber  412  between the gaps defined by upper and lower brackets  438  and  442 , respectively. It may be desirable to remove filter  436 , for instance, to replace the enclosed filtration material.  
      A partition  446  extends vertically between upper and lower walls  414  and  406 , respectively, at a location downstream from second filter  436  and, in combination with wall  416 , defines a fan housing  448 . Housing  448  contains a fan  450  operably connected to controller  407 . Partition  446  is either made from a porous material, or defines grooves extending therethrough such that rotation of fan blades  452  draws air into fan chamber  412  from cooking chamber  334  as described above. Fan  450  further expels the twice-filtered air from filtration chamber  411 , through openings  454  formed in wall  416  along the direction of Arrows E, and out a vent  456  formed in upper housing wall  404  at a location between walls  405  and  416  along the direction of Arrows F.  
      Referring still to  FIG. 26 , controller  407  advantageously senses whether both filters  422  and  436  are installed in filtration chamber  412 , and controls the operation of fan  450  accordingly. In particular, filter  436  is operably linked to a switch  458  having a depressible plunger  460  that is normally in an “up” position. A flexible (preferably metallic) plate  461  defines a first end  462  attached to the upper edge of surface  443 , and a second end  464  downstream from first end  462  with respect to the direction of travel when filter  436  is inserted into filtration chamber  412  along the direction of Arrow G. Second end  464  of plate  461  extends up from surface  430  an amount substantially equal to the amount that plunger  461  protrudes up from surface  443 . Accordingly, when filter  436  is not installed in chamber  412 , switch  458  is open. Switch  458  is connected to controller  407 , which senses the normally open position of switch  458  and determines that filter  436  is not installed in filtration chamber  412 . Accordingly, controller  407  prevents operation of fan  450  when switch  458  is open.  
      Referring to  FIG. 27 , when filter is inserted into filtration chamber  412  along the direction of Arrow H, the bottom edge of frame  437  rides up over first end  462 , and travels along plate  461  until depressing the downstream end  464  against plunger  460 , thereby closing switch  458 . Controller  407  senses the closed position of switch  458 , and thus concludes that filter  436  has been installed. It should be appreciated that a pair of switches  458  could be provided proximal front and rear walls  409  and  411 , such that controller  407  could determine whether or not filter  436  has been fully inserted in chamber  412 .  
      Referring again to  FIG. 24 , baffle filter  422  likewise is operably linked to a normally open switch  466  constructed as described above, and engages a flexible plate (not shown) in the manner described above. Switch  466  is connected to controller  407 , which determines whether both filters  422  and  436  have been installed. Controller  407  enables fan  450  to operate only when both switches  458  and  466  are closed, thereby indicating that both filters  422  and  436  have been installed in filtration chamber  412 .  
      If controller  407  also controls operation of oven  320 , controller  407  could enable operation of heating assemblies  364  and  366  only when filters  422  and  436  have been installed. Furthermore, an air flow rate sensor  470  can be positioned proximal vents  456  and coupled to controller  407  to determine the flow rate of filtered air out the hood  400 . Controller  407  can prevent operation of heating assemblies  364  and  366  when the flow rate out of the hood  400  falls below a predetermine threshold indicating that either or both filters  422  and  436  have become clogged and require maintenance. Controller  407  could further compare the flow rate sensed at sensor  470  to that sensed at sensor  419  to determine whether either filter  422  and  436  are clogged. Furthermore, the reduced flow rate may be indicative of an open hood door  472  (which provides access to filtration chamber  412  along with a rear door, not shown). Alternatively, magnetic sensors of the type described with respect to oven  320  could be present on hood  400  to sense corresponding magnets carried by door  472 , and coupled to controller  407  to directly sense when the hood door  472  is open and prevent operation of heating elements  364  and  366 . In this manner, controller  407  prevents oven  320  from expelling unfiltered (or insufficiently filtered) air into the ambient environment.  
      Referring now to  FIGS. 20, 28 , and  29 , hood  400  includes a door lock assembly  470  that, during operation, prevents the oven door assembly  338 , and in particular the inner pane  390  from being immediately fully opened. It should be appreciated that hood could carry a similar door lock configured to engage the rear door assembly  340 .  
      Door lock assembly  470  includes a plate  472  extending forwardly through an opening  405  formed in the front end of lower wall  406  at a location proximal handle  394  (i.e., the free end of door assembly  338 ). A flange  474  extends down from the forward end of plate  472 . A spring  500  is seated in a cup-shaped retainer wall  476  disposed in lower wall  406  having an upper end engaging the bottom surface of plate  472 , thus biasing plate  472  upwards. The vertical position of plate  472  is further controlled by a plunger  496  coupled to an actuator  498  which could, for instance, be a solenoid valve that is electrically connected to controller  407  and supported by an L-Bracket  495  extending from the lower end of front wall  409 .  
      When door assembly  338  is closed, as indicated by controller  407  when sensing that inner pane  390  is closed, actuator  498  causes plunger  496  to bias plate  472  to a depressed position against the force of spring  500 . When plunger  496  is in the depressed position, the lower end of flange  474  interferes with upper horizontal frame member  389 .  
      Referring now to  FIG. 30 , flange  474  is spaced slightly forward with respect to frame member  389 , such that door assembly  338  can be partially opened an amount equal to the offset between flange  474  and frame member  389 , thereby permitting air to flow into cooking chamber  334  as soiled air travels from cooking chamber  334  to filtration chamber  412 . Once controller  407  senses that door  338  has been opened, actuator  498  continues to depress plate  472  for a predetermined period of time until it is determined that the remaining grease-laden air disposed in cooking chamber  334  has been filtered and exhausted form hood. In accordance with the preferred embodiment, and depending on the minimum air flow rate through vent  456 , door assembly  338  is prevented from opening past the position illustrated in  FIG. 30  until the expiration of a lag time, for instance between ten and thirty (preferably twenty) seconds. Alternatively, the lag time can be calculated by controller  407  based on the amount of time necessary to replace the volume of soiled air inside cooking chamber with fresh ambient air as a function of the size of cooking chamber  334  and output flow rate as sensed by sensor  470 .  
      Once the lag time has elapsed, actuator  498  removes the downward force on plunger  496 , thereby enabling the force of spring  500  to bias plate  472  to its raised position, whereby the lower end of flange  474  is disposed entirely above horizontal frame member  389 . Consequently, door assembly  338  is permitted to fully open such that the spit assembly  352  and corresponding cooked food product can be removed from cooking chamber  334 . Once door assembly  338  is closed, during oven operation, actuator  498  again engages plunger  496  to depress plate  472  and prevent door  338  from being fully opened until the expiration of the predetermined period of time.  
      The above description has been that of the preferred embodiment of the present invention, and it will occur to those having ordinary skill in the art that many modifications may be made without departing from the spirit and scope of the invention. In order to apprise the public of the various embodiments that may fall in the scope of the present invention, the following claims are made.