Multizone oven with variable volume steam-assisted cooking zones

A multi-compartment oven provides separate humidity controlled zones using separately controlled steam generators and humidity resistant partitions between cavities. A removable humidity wall may allow resizing of the cavities while providing the necessary humidity sealing and may be augmented by venting control based on neighboring cavity usage.

CROSS REFERENCE TO RELATED APPLICATION

BACKGROUND OF THE INVENTION

The present invention relates to ovens for the preparation of food, and in particular, to a multi-zone oven providing independent control of the temperature and use of steam in each zone.

Combination steam and convection ovens (“combi-ovens) cook using combinations of convection and steam. In convection cooking, heated air is circulated rapidly through the cooking compartment to break up insulating, stagnant layers of air around the food, thereby increasing the rate of heat transfer. Higher velocity air typically increases the rate of heat transfer from the air to the food by further disrupting the insulating, stagnant layers of air around the food, as does striking the largest surface of the food with air delivered from in a generally perpendicular direction to the food, since perpendicular air is more disruptive to such insulating, stagnant layers of air than air gliding across the largest surface of the food. High humidity further enhances the rate of heat transfer to the food as a result of the high specific heat of water compared to dry air, and such humidity may be used at temperatures approximating the boiling point of water (often called “steam-cooking”) or in a superheated state well above the boiling temperature of water (often called “combi-cooking”). Steam can also reduce water loss from the food. Combi-ovens are described, for example, in U.S. Pat. Nos. 7,307,244 and 6,188,045 assigned to the assignee of the present invention and hereby incorporated by reference.

Professional kitchens are often called upon to simultaneously prepare a wide variety of dishes, each one optimally being cooked for different periods of time at different cooking temperatures, optimally according to a schedule that enables multiple different dishes to emerge from the oven at the same time for the purpose of coordinating simultaneous delivery of a variety of “fresh out of the oven” food items to different customers at the same table, U.S. Pat. No. 9,677,774, also assigned to the assignee of the present invention and hereby incorporated by reference, describes a multi-zone convection oven that can provide independently temperature, blower speed and cook time controlled cooking cavities for this purpose.

SUMMARY OF THE INVENTION

The present invention improves over the prior art multi-zone temperature controlled ovens by providing a multi-zone “combi oven,” that is, an oven having separate compartments which can be independently controlled both in temperature and with respect to the use of steam. In this regard, the invention addresses the difficult problem of handling and containing fugitive moisture passing between cavities, particularly in light of abrupt pressure differences that are generated by the introduction of steam into a closed cavity, and in providing effective condensation handling.

In one embodiment, the invention provides removable “humidity walls” that function both to contain high-pressure steam and moisture within a given compartment and provide a drainage path for condensation. By permitting the ability to remove these humidity walls, improved versatility of the oven space is provided.

Specifically, then, at least one embodiment of the present invention provides a multi-cavity oven having a housing defining an interior cooking volume surrounded by insulated outer walls and at least one door that may open and close to provide access to the interior cooking volume. At least one humidity blocking barrier subdivides the cooking volume into cooking cavities permitting different humidities. A steam generator system introducing steam into selective cooking cavities according to an electric signal is associated with each cavity and a set of fans circulates air independently through the cooking cavities in isolation from the other cooking cavities. In addition, each cavity provides a separate heater and a thermal sensor. A controller receives user commands to independently set temperature and humidity of the different cooking cavities.

It is thus a feature of at least one embodiment of the invention to provide a single oven that can manage markedly different cooking environments in terms of both temperature and humidity to cook different dishes simultaneously.

Significantly, the humidity blocking barrier may be movable to allow adjustment of the size of at least one cooking cavity during operation of the oven.

It is thus a feature of at least one embodiment of the invention to permit compact cavity sizes maximizing the ability to simultaneously provide different cooking schedules within a given oven size while still accommodating the need, on occasion, for large cooking volumes by permitting removable partitions.

The oven controller may operate to coordinate operation of the heater, steam generator, and thermal sensor of the at least one combined cooking cavity adjusted in size.

It is thus a feature of at least one embodiment of the invention to provide a control system that can accommodate changes in oven geometry not only with respect to the heating but also with respect to the steam generation resulting from changes in cavity size.

The humidity blocking barrier may be supported against surfaces extending outwardly from inner walls of the cooking volume and may further include an elastomeric seal compressed between the humidity blocking barrier and the surfaces when the humidity blocking barrier is pressed against the surface perpendicular to its broadest extent.

It is thus a feature of at least one embodiment of the invention to allow the humidity blocking barrier to be easily inserted and removed without interference from and friction between the oven walls and the elastomeric seals which may be compressed for sealing in a direction perpendicular to the insertion and removal direction after insertion.

The elastomeric seals may be attached directly to and supported by the humidity blocking barrier.

It is thus a feature of at least one embodiment of the invention to allow for easy access and replacement of the elastomeric seals, for example, when the humidity blocking barrier is removed, either by removal from the humidity blocking barrier or replacement of the humidity blocking barrier and seals together as a unit.

The multi-cavity oven may further include at least one clamp attached between the humidity blocking barrier and the cooking cavity for compressing the humidity blocking barrier toward the outwardly extending oven wall surface for compression of the gasket.

It is thus a feature of at least one embodiment of the invention to provide an improved seal by positive clamping of the seal elements.

The clamp may be operable after the humidity blocking barrier is placed fully within the oven volume.

It is thus a feature of at least one embodiment of the invention to simplify insertion and removal of the humidity blocking barrier by relieving clamp pressure until the barrier is installed.

The multi-cavity oven may further include a door providing a glass panel forming a front of the cooking volume and may provide an elastomeric seal positioned between the glass panel and a front edge of the humidity blocking barrier.

It is thus a feature of at least one embodiment of the invention to provide an easily cleanable inter-door surface comprised of an unbroken single glass panel sealing against the multiple cavities.

The elastomeric seal may be attached to the front edge of the humidity blocking barrier and extends laterally left and right therefrom to overlap an elastomeric seal providing a perimeter about an opening sealed by the door when the door is in a closed position over the cooking volume.

It is thus a feature of at least one embodiment of the invention to provide a good sealing not only between the oven and outside air but also between the different cavities while still allowing removability of the humidity blocking barriers and visibility of the contained food.

The elastomeric seal may present a concave surface separating a path between cooking cavities so that excess pressure on the concave side of the elastomeric seal promotes sealing of the elastomeric seal against the flange.

It is thus a feature of at least one embodiment of the invention to provide an easily engaged elastomeric seal that self-energizes for improved sealing under high-pressure spikes generated by rapid steam generation.

The jet plates may be substantially identical.

It is thus a feature of at least one embodiment of the invention to employ a separate humidity blocking barrier so that the jet plate design can be simplified, reducing confusion with respect to installation of the jet plates such as could occur if one let plate included a humidity blocking barrier incorporated therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now toFIG. 1, a multi-zone steam-assisted oven10may provide for a housing12having upstanding right and left outer sidewalls14aand14band upstanding rear wall14cextending therebetween. These three walls14join generally opposed upper and lower walls14dand14e, the latter providing support so that the oven10may rest on a cart or the like (not shown).

The walls14enclose a generally rectangular cooking volume16having an opening18through a front wall14fto provide access to the cooking volume16for inserting and removing food. The cooking volume16may be subdivided into cooking cavities20a,20h, and20c(for example) from top to bottom, by means of shelf assemblies22as will be described in more detail below.

The perimeter of the opening18and a front edge of each shelf assembly22support an elastomeric gasket24that may seal against an inner surface of a glass panel26providing an inner surface of a door28. The door28hinges about a vertical axis at the front edge of wall14bto move between open and closed states, the latter sealing the cavities20a-cwith respect to the outside air and with respect to each other. The door28may be held in the closed state by a latch mechanism and handle29as is generally understood in the art. In one embodiment the glass panel26of the door28extends as a continuous surface over the openings of each of the cavities20, however the invention also contemplates separate glass panels or suffer doors associated with each of the cavities20.

An upper portion of the front wall14fmay support user controls30including input control such as one or more dials and output display such as an LCD display for communicating with the user. A condensation tray32may extend forward from a lower edge of the front wall14fto catch condensation from the inner surface of the glass panel26when the door28is being opened or closed.

Referring now also toFIGS. 2 and 3, each of the shelf assemblies22is composed of a stack of four separately removable elements that may be inserted into the cooking volume16to subdivide the cooking volume16into cooking cavities20or removed to combine cooking cavities20into larger cooking cavities20.

An uppermost component of the shelf assembly22is a wire rack34having an outer wire element36forming a generally rectangular perimeter defining an edge of the shelf assembly22. The outer wire element36supports a set of parallel wire rods38between a front and rear edge of the wire element36that may support food items while allowing ample airflow therearound.

The outer wire element36has, in each corner, a downwardly extending foot40serving to support the wire rack34in spaced elevation above a generally rectangular and planar upper surface of a lower jet plate42.

The lower jet plate42provides an upper surface perforated by slots and openings44and stiffened upwardly extending ribs46between a front and rear edge of the lower jet plate42. A jet plate42of this general design is discussed in US patent application 2016/0356506 assigned to the assignee of the present invention and hereby incorporated by reference. As discussed in this reference, the lower jet plate42provides an internal channel beneath the upper surface of the jet plate42conducting air from a rearward opening edge of the jet plate42through the jet plate42to exit from the slots and openings44as a set of structured air jet50openings44. Referring momentarily toFIG. 6, the jet plate42may include an internal horizontal baffle41changing the cross-sectional area of the jet plate42to provide more uniform airflow through the multiple openings44. Generally, the size of the openings44and the cross-section of the channel within the jet plate42will change to promote the desired airflow pattern upward onto food supported by the rack34.

The lower surface of the jet plate42in the shelf assembly22rests on a humidity wall52being a generally rectangular panel sized to extend the full lateral and front to back dimensions of the cooking volume16and operating to seal moisture against passage between cooking cavities20. The lower left and right edges of the humidity wall52have downwardly extending elastomeric gaskets54that may be supported on a flange56extending inwardly from the inner surfaces of the left and right inner walls of the cooking volume16. This ledge surface may be tipped from horizontal as it travels toward the rear of the cavity20by an angle59so that the upper surface of the humidity wall52slopes rearwardly and optionally downward from left to right as indicated by drainage arrow57. The slope promotes water flow to a rear edge and right corner of the humidity wall52.

A front edge and rear edge of the humidity wall52also support an elastomeric gasket58extending forward and rearward therefrom as will be discussed in greater detail below.

Positioned beneath the humidity wall52, is an upper jet plate42′ of the next lower cavity20. This jet plate42′ has openings44′ on its under surface to direct structured air jets50′ downwardly and may be identical in structure to jet plate42but simply inverted for ease in manufacturing and field use. This upper jet plate4T may be independently supported on a ledge60to be removed and inserted without adjustment or removal of the rack34, the lower jet plate42, or humidity wall52.

Referring now toFIGS. 4 and 5, the humidity wall52may provide for a generally planar upper surface62supporting along its left and right edges downwardly opening rectangular channels64that may receive and retain supporting ribs66of the elastomeric gasket54therein. A sealing portion67of the gasket54may extend downwardly from the supporting ribs66having a lower tip68flexing to seal as supported against the upper edge of inwardly extending flange56. This flexible tip68when compressed bends into a concave wall70such that over-pressure on the side of the gasket54facing the concave wall70tends to force the tip68into tighter engagement with the flange56thereby better resisting leakage against pressure spikes.

Referring again toFIG. 4, the humidity wall52may also support at its front and rear edges, an outwardly facing rectangular channel72(facing forwardly at the front edge of the humidity wall52). Each channel72also receives a supporting rib66to provide a correspondingly extending frontmost gasket58with sealing portions67extending generally outwardly from the humidity wall52within the plane of gaskets54to complete a sealing around a periphery of the humidity wall52between cavities20and glass door surface26.

Referring now toFIGS. 3 and 6, the wire rack34, lower jet plate42and humidity wall52may be inserted together or individually as indicated by arrow69into a cooking cavity (for example, cavity20h) with the front edges of the assembly slightly elevated to reduce sliding resistance to the insertion caused by friction between the gaskets54and the flange56thereby promoting easy insertion and removal. In this orientation, a rear edge of the wire rack34may fit beneath a capture flange80attached to a rear inner wall of the cooking cavity20band located to slightly compress the gasket54at that rear edge against the rear edge of flange56when the rearward gasket58presses against the rear horizontal ledge of the cavity20to seal against that surface.

The front edge of the wire rack34, lower jet plate42, and humidity wall52may then be pressed downward as indicated by arrow71compressing the sealing portion67of the gasket54against the flange56along the full length of that flange56to provide a good sealing engagement. Generally, the shelf assemblies22are intended to be installed and removed repeatedly without damage and without the need for tools.

Referring now toFIG. 6, a swivel clip74pivotally attached to the inner sidewalls of the cooking cavity20may then be pivoted about a pivot point76to capture a front edge of the wire rack34on a hook portion78holding the gasket sealing portion67in compression against the flange56through force exerted on that gasket54through the jet plate42and the humidity wall52by the captured wire rack34.

In this position, closure of the door (shown, for example, inFIG. 6) will compress the front gasket58against the inner surface of the glass panel26completing the sealing process.

Referring now toFIGS. 5, 7 and 8, the front gasket58may extend in cantilevered fashion away from the humidity wall52at its left and right sides and may be given a concave bevel cut75so that when the humidity wall52is fully seated within the oven, the front gasket58sealingly engages the vertical extent of the gaskets24attached to the front wall14fon the left and right sides of the openings18. In this way, each cooking cavity20a-cprovides gasketing that fully engages the glass panel26of the door28when the door28is closed and that fully encircles each cavity20preventing passage of heated air or steam between cavities20along the inner surface of the glass panel26.

Referring now toFIGS. 5 and 9, when the door28is closed over a cooking cavity20, the jet plate42is pressed rearwardly against a rear upper wall of the cooking cavity20to seal with air outlet openings79which will be discussed below. The openings79may be closable by a movable or slidable shutter81controlled, for example, by an external operator83, as described in US patent application 2016/0356504 assigned to the assignee of the present application and hereby incorporated by reference. The shutter81allows a given shelf assembly22to be removed creating uncontrolled airflow unmoderated by a jet plate42.

The right and left sides of the jet plate42in position on the humidity wall52will be slightly undersized to reveal small channels77on the left and right sides of the jet plates42exposing the upper surface of the humidity wall52. These channels77provide for a path to conduct grease and water off of the upper surface of the jet plate42following a general slope of the upper surface of the humidity wall52indicated by arrow57toward a rear right corner of the cavity20. In this regard, a small lip or slope85(shown inFIG. 4) may be provided on the upper surface of the humidity wall52to reduce flow of liquid down to the underlying gasket54. In addition, or alternatively, the humidity wall52may incorporate sloped channels.

A drain tube82is positioned at an orifice through the rear or side wall of the cavity20adjacent to the drainage surface of the humidity wall52above the location of the rear gasket58and side gasket54to receive that drainage. In this way, the cavities20beneath a given cavity20need not be pierced to provide a path of drainage, for example, of steam, condensation, or the like.

Referring now toFIG. 10, the drain tubes82for cavities20aand20hmay connect to P-traps84which may be partially filled with water to provide a trap preventing direct gas flow and offer a resistance to backflow that prevents steam or over-pressure gases from moving between cavities20instead of exiting through conduits leading to a condenser sump86. The condenser sump86may be positioned below cavity20and may provide a direct path through exit port88to the atmosphere. Generally, the P-traps84allow for the escape of liquid as liquid fills the lower trap portion and overflows into a downwardly extending drain pipe to the condenser sump86. In this way combined drainage to a single shared reservoir can be provided without risk of moisture passing between cavities20through that common connection.

The front tray32may also communicate with the condenser sump86which holds a pool of cooling water, for example, as described in U.S. Pat. No. 8,997,730 assigned to the assignee of the present invention and hereby incorporated by reference. In this regard, the condenser sump86may provide for a grease trap, for example using a divider wall91extending slightly downward into the water90to block the passage of grease to a water drain93. The lowest cavity20does not employ a humidity wall52or drain tube82but instead provides a central tubular drain92extending directly down into the condenser sump86slightly beneath the surface of the water90to provide an effective trap mechanism similar to P-traps84. It will be appreciated that other backflow limiting mechanisms may be used to prevent the interchange of gases between cavities20including, for example, one-way valves, resistive constrictions, and the like.

Referring now toFIGS. 3 and 11, positioned rearward from each cavity20is a dedicated fan94, for example, being a centrifugal fan having a squirrel cage impeller95surrounded by an involute housing96. The fans94may be mounted with rotation of the squirrel cage impeller95about a horizontal axis extending from the right to left wall of the oven10with the squirrel cage impeller95centered with respect to the volume of the cavity20. The volume of the housing96may provide an opening98directing air along a tangent line99that is tipped upward with respect to horizontal by about 30 degrees allowing a larger squirrel cage impeller95to be fitted within the compact height dimensions of the cavity20while still delivering air to the upper and lower jet plates42. A baffle plate100faces the opening98at a distance102less than a smallest dimension104of the opening98to provide high turbulence and high resistance to airflow that evens the distribution of airflow into the channels79into the upper jet plates42′ and lower jet plates42. In this respect, the baffle plate100may be asymmetric about the tangent line99to provide desired partitioning of the airflow and also operate when cleaning solution must be distributed through the jet plates42.

Referring toFIG. 11, each squirrel cage impeller95may be driven by a dedicated speed-controlled motor106operated by solid-state motor drive108. The shaft connecting the motor106to the squirrel cage impeller95may continue past squirrel cage impeller95to a water distribution fountain tube110to rotate the fountain tube110along the same axis as rotation of the squirrel cage impeller95but displaced leftward therefrom.

Referring also toFIGS. 12 and 13, the fountain tube110may be a hollow cylinder extending along a length112at least three times its diameter114and perforated with multiple holes116distributed along its length and around its circumference. This high aspect ratio of the fountain tube110allows water injected into the fountain gibe110through freshwater port118to be distributed laterally along the axis of rotation of the fountain tube110for a substantial distance before exiting the tube in jet sprays120. The fountain tube110may be placed concentrically within a helical heater tube122to spray water outward evenly around the inner surface of the helix and length of the heater122. By distributing the water evenly about the inner surface of the helix of the heater122, stress and possible damage to the heater122is reduced. Water to the freshwater port118may be controlled by electronically controlled valve128as will be discussed below.

Referring toFIG. 11, the helical heater tube122may be positioned in a side compartment123behind and to the left of the cavity20and to the left of the centrifugal fan94which may receive air from the side compartment123to be expelled through the openings79(for example, shown inFIG. 3) into the jet plates42and returned through a vent124at the rear of each cavity20and through a side vent125and side channel126to be heated by the heater122.

Passive insulation such as fiberglass130may surround the outside of the side channel126and be positioned between the motor106and the fan94and over the rear walls of side compartment123and right-side walls of cavity20. The insulation between the fan94and the motor106provides the motor106with a heat-isolated environment which may be vented by a vent fan131or the like.

Referring again toFIG. 3, a double wall132, for example, made of metal, may be positioned above and or below the fan94side compartment123and the side channel126to reduce the leakage of heat between circulating air of vertically adjacent cavities20. Optionally, the space between this double wall132may be filled with a passive insulator such as fiberglass.

Referring now toFIG. 14, each of the cavities20may provide for a fresh air inlet port134and an outlet port136leading between the cavity20and ambient air. Generally the fresh air inlet ports134may be separated so that there is no tendency for steam or humidity to be able to communicate through the fresh airports between cavities20without substantial dilution by ambient air. Either the inlet port134or the outlet port136(in this this case the outlet port136) may pass through an electronically controlled valve138controlled by a controller140so that exchange of fresh air or exhausted steam from each cavity20may be separately controlled. Steam exhausted through valves138may pass upward to a condenser142having a cooling surface condensing steam before venting the steam through an opening144to the atmosphere. Condensate passes downward along a sloped upper wall of the condenser142to be received in the condenser sump86described above.

Referring now also toFIG. 15, the controller140may execute a control program controlling the cooking in each of the cavities including temperature and humidity as a function of time. In this regard, the controller140may identify which of the cavities20is associated with steam generation and may control the valve128discussed above with respect toFIG. 11in a pulsed manner to create steam.

When one or more of the cavities20is providing steam-augmented cooking (either steam or combi cooking), the controller140may control the valves138to open the valves138associated with any cavity20having dry cooking (D) when it is adjacent to a cavity20having steam or combi-heating (S/C). This control of the valves138scavenges any moisture leaking through the humidity walls52into the dry cooking cavities20. Those cavities20using steam or combi-cooking normally have their valves138closed during that steam application. This is also true for cavities20having dry cooking when there is no adjacent steam cooking cavity. Thus, for example, looking at the third column ofFIG. 15, if cavity20bis cooking with steam, and cavities20aand20care cooking dry, the valves138of cavities20aand20cmay be opened during the cooking process, or periodically, to expel moisture. This active approach to humidity control augments the sealing of the humidity walls52. It will be appreciated that this active venting may be alternatively limited to times of actual steam generation that produce pressure spikes or may be limited to times when two adjacent cavities are both generating steam and not when a single cavity is generating steam.

Referring now toFIGS. 14 and 16, a cleaning of the cavities20may be provided through the use of a cleaning manifold141extending vertically along a rear corner of the cooking cavities20, for example, adjacent to the drain tubes82and providing nozzles143extending into the cavities20from vertical sidewalls of the cavities20to direct a spray of water away from the drain tubes82against exposed surfaces of the cavities20. Water from those surfaces is then drawn into the vents125and124for circulation by the fan94and possible heating by the heater122and through the interior of the jet plates42. Excess water is collected by the drain tubes82and provided to the sump86where, as activated by the controller140, a pump146(shown inFIG. 17) may pump water back through the manifold141for constant recirculation. In this process, a cleaning surfactant or the like may be introduced into the water for improved cleaning ability. Generally, the surface of the jet plates42or the channels77described above with respect toFIG. 9may sloped downwardly toward the drain ports82to provide complete drainage of the cavities20.

Multiple such manifolds141may be provided to ensure complete coverage of the cavities. In one embodiment, a second manifold141′ may pass into the air channels communicating between the cavity20and the blower95(shown inFIG. 11) to introduce additional water into these areas for heating and circulation by the fan.

Referring now toFIG. 17, the controller140may provide for a microprocessor150communicating with a memory152holding a stored program executed by the microprocessor150for the control of the oven as discussed herein and generally to allow independent temperature and humidity control of each cavity20according to predefined schedules. In this regard, the controller140may receive input signals from user controls30(also shown inFIG. 1), the latter, for example, providing information designating whether steam or combi cooking will be used in each cavity20, and may provide control signals to each of the valves138discussed above, and Generally, for each cavity20, the controller140will also communicate with the motor drives108associated with each motor106for control of motor speed and direction as desired based on these user inputs and or a cooking schedule. The controller140may also received signals from temperature sensors155in each cavity20and control signals may be received from the controller140by solid-state relays154controlling power to the helical heater tube122when the heaters are resistance heater coils such as “cal” rods or by corresponding gas valves and gas burner assemblies when the heaters are gas heaters in response to those signals and a cooking schedule and/or use set temperature.

Controller140also provides a control signal to the freshwater valve128discussed above with respect to introducing water to the helical heater tube122to create steam. The controller140also controls a freshwater valve156providing makeup water to the sump86, for example, by monitoring the signal of a temperature probe158measuring the temperature of that water. In this regard, the controller140may add additional water to the sump86when the temperature of the water in that sump rises beyond a predetermined level allowing excess heated water to overflow through a drain pipe. The controller140also controls the pump146to affect the cleaning process described with respect toFIG. 15by pumping water and cleaning solution through the manifold141to recycle back down to the drains into the sump86.

The controller140may also adjust a control strategy upon the removal of a shelf assembly22, for example, by combining readings of associated temperature sensors155of the combined cavity20, for example, by using to an average reading or selecting a maximum reading among temperature probes. In addition, the controller140may control fan speed for the two fans94of the combined cavity20to coordinate the operation of those fans94to accommodate the different airflow patterns associated with larger cavities. This is described generally in US patent application 2017/0211819 assigned to the assignee of the present application and hereby incorporated by reference. Significantly, in the present invention, when cooking cavities20are combined, the generation of steam as described above may be coordinated between the two different helical heater tubes122, for example, using only one heater122for the combined cavities to reduce excess moisture and using the remaining heater122to provide improved heat recovery or alternatively alternating between the heaters122when steam is generated to reduce scaling buildup and the like. Under this coordination, the generation of steam or the control of heat or the control of venting is no longer independent for the steam generators, heaters, or vents of the combined cooking cavity20.

Referring now toFIG. 18, many of the above-described inventive features may be applied to an alternative design of the oven10providing an outer cabinet160for supporting and receiving multiple independent oven modules162. Each oven module162provides a separate housing supporting upper and lower jet plates42to independently implement cavities20a-20c. Notably, the oven modules162do not have removable humidity walls52which are replaced by nonremovable upper and lower walls164of each oven module162. Modules162may be stacked on each other as separated by spacers166providing exit room for a drain tube168serving the same function as drain tube82described above but being arbitrarily positioned, for example, central to the bottom wall164. The drain tubes168may be interconnected by P-traps84to a common sump86has shown for example inFIG. 2. The cabinet160may provide for a manifold that may connect each of the drain tubes168to the necessary P-trap84and shared sump86.

Each of the modules162may have a self-contained and independently operable helical heater tube122, fan94, motor106, and temperature sensor155(for example, seen inFIG. 16) and may provide for a harness169allowing electrical connection to a central controller140in the cabinet160when the modules162are assembled therein. Similarly, each oven module162may have a nozzle143that may be connected to a manifold141(shown inFIG. 15) associated with the cabinet160and inlet port134and outlet port136, one of which may connect to a valve138described above with respect toFIG. 14.

By using this modular approach, different size ovens can be readily created by insertion of different numbers of modules into an appropriately sized cabinet160.