Patent Description:
The invention generally relates to systems and methods for automatically heating and cooking food products using cooking medium in a cooking apparatus, such as a fryer and, more particularly, to systems and methods for optimizing the heating and use of the cooking medium in such fryers.

Oil-based frying is commonly used as a cooking method for a wide range of food, such as poultry, fish, potato products, and the like. Commercial fryers include one or more fry pots (also referred to as cooking chambers) that are filled with a cooking medium such as oil or solid fats. Heat is typically provided to the cooking medium using an electrical heating element submerged in the cooking medium or a gas burner thermally coupled to the cooking medium through the walls of the fry pot. When the cooking medium reaches a preset cooking temperature, food products are placed into the cooking medium for a predetermined amount of time during which the food products are cooked by heat from the cooking medium. To facilitate insertion and removal of the food products, the food products are typically placed inside a container, such as a wire basket, and the container lowered into the cooking medium for the predetermined amount of time.

Although many conventional fryers require manual movement of baskets of food products into and out of the cooking medium, some alternative fryer designs have been developed for automatically moving food products through a cooking cycle. In this regard, some baskets in fryers are configured to slide on a rail for loading and unloading of food products or can be automatically raised and lowered out of the oil. This type of movable basket requires complicated control mechanisms to track the basket locations. Augers are also used in some other types of fryers to move food products horizontally from submersion in oil, up and out to a dumping station. Augers are limited by slow operational speed and a resulting mess created by oil at the output side of the fryer. Conveyor belts and paddles are also commonly used in fryers to ensure even cooking and flow of the food products through the oil within a frying chamber, but these require multiple moving parts and can result in rough handling of the food products.

The cooking medium of a conventional fryer is normally re-used for multiple cooking cycles, which may include cooking cycles for different food products. However, the cooking medium degrades over time. This degradation may be due to contamination by particles shed by the food products being cooked and from chemical degradation due to heat, oxidation, and reactions with the food products. In addition, as food particles accumulate in the cooking medium, the flavor characteristics of the food particles may become infused in the cooking medium. This infusion may adversely affect the quality of cooked food. For at least these reasons, the cooking medium must occasionally be replaced and/or filtered. Known contemporary filtering systems require the operator to manipulate manual valves to route the cooking medium through the filter and to return it to a cooking vessel, e.g., a frypot, disposed within the fryer. Even experienced operators may open or close the valves incorrectly, which increases operating expenses through lost time. Periodically, the drain pan under the fryer may be removed for cleaning or to discard the cooking medium. If the operator forgets to replace the drain pan and opens the drain valve, the cooking medium drains onto the floor and is wasted, which greatly increases operating expenses.

Fryer manufacturers have recently developed improved fryer systems and methods to help address some of the shortcomings with conventional food product movement and filtration systems as set forth above. For example, the original assignee/Applicant of this application developed an automated fryer as shown and described in International Patent Publication No. <CIT>, entitled "Automatic Fryer". This fryer moves food products using a continuous flow of cooking medium through a series of gates, and the gates are selectively opened to allow batches of food product to move from portion to portion along the length of the fryer. The continuous flow of cooking medium is driven by a recirculating pump system, and the cooking medium is therefore continuously filtered during cooking operations. Technical advantages of this design include improved temperature uniformity of the cooking medium for all food products because the cooking medium is being continuously circulated, and the removal of manual food product movement with baskets. This fryer design improves the functionality and operation of conventional fryers, but further improvements and refinements of the design continue to be desirable. For example, the oil life span for this fryer design can be relatively short (when no top off procedure was used) and therefore could be improved. Deep far fryers are for instance disclosed in the prior art in <CIT>, <CIT> and <CIT>.

Accordingly, it is desirable to further reduce and/or optimize the amount of cooking medium required to operate the fryers, while improving the temperature and flow characteristics of cooking medium in automated fryers. It is also desirable to optimize the heating of cooking medium in all types of fryers where reduced oil volume use is desired.

To achieve the above design objectives and further improve the fryer art, in one embodiment an automatic cooking system for frying food products is provided. The system includes a cooking vat configured to hold a cooking medium and to receive food product. The cooking vat defines at least one elongated lane extending between an inlet end where the food product is inserted into the cooking vat and an outlet end where the food product is removed from the cooking vat. Each lane of the cooking vat includes a bottom wall and sidewalls extending along the lane. The system also includes an oil recirculation and filtration system in communication with the inlet and outlet ends. The oil recirculation and filtration system is configured to generate a continuous flow of cooking medium from the inlet end to the outlet end. The system further includes a heating element coupled to an exterior of the cooking vat along at least one of the bottom wall and the sidewalls. The heating element is configured to transfer heat by conduction into the cooking vat to uniformly heat the cooking medium. Positioning the heating element on the exterior of the cooking vat reduces a volume of the cooking medium that is needed to operate the automatic cooking system with the continuous flow of the cooking medium, which moves food product between the inlet and outlet ends during a cooking process.

In one aspect, the heating element includes at least one printed heating element directly coupled to the exterior of the cooking vat. The printed heating element further includes a resistor circuit trace that is spread over the exterior of the cooking vat to provide heat energy into the cooking vat.

In another aspect, the heating element is connected to the bottom wall of the cooking vat. For example, the heating element may be sized to engage a substantial majority of a surface area defined along the bottom wall of the cooking vat, to thereby provide generally uniform heating of cooking medium in the cooking vat. In such embodiments, the heating element may be connected to only the bottom wall of the cooking vat. In other embodiments, the heating element is connected to the bottom wall and the sidewalls of the cooking vat.

In a further aspect, the system also includes a controller and a temperature sensor. The controller is operatively coupled to the oil recirculation and filtration system and to the heating element. The temperature sensor is coupled directly to the heating element and configured to measure a heater temperature of the heating element, and then communicate the heater temperature to the controller. The controller controls the heating element to prevent the heater temperature from exceeding a temperature that may lead to a dry fire condition. The heating element, in some embodiments, may include a plurality of heating elements connected to the exterior of the cooking vat, and each heating element has a temperature sensor coupled directly to the heating element.

In yet another aspect, the bottom surface of each lane in the cooking vat is angled upwardly along at least a portion of a length from the inlet end to the outlet end. The combination of the bottom surface angling, the positioning of the heating element, and the continuous flow of cooking medium allows for cooking cycles to be performed on food products resulting in high quality of cooked food products and minimized use of oil volume, thereby improving the art of elongated fryers that move food product while cooking it.

In another embodiment in accordance with the invention, an automatic cooking system for frying food products is provided. The system includes a cooking vat configured to hold a cooking medium and to receive food product. The cooking vat defines at least one elongated lane extending between an inlet end where the food product is inserted into the cooking vat and an outlet end where the food product is removed from the cooking vat. Each lane of the cooking vat includes a bottom wall and sidewalls extending along the lane. The system also includes an oil recirculation and filtration system in communication with the inlet and outlet ends. The oil recirculation and filtration system is configured to generate a continuous flow of cooking medium from the inlet end to the outlet end. The system further includes a heating element coupled to at least one of the bottom wall and the sidewalls. The heating element includes at least one printed heating element directly coupled to the cooking vat so as to transfer heat by conduction to uniformly heat the cooking medium. The printed heating element defines a low profile that does not impede the continuous flow of the cooking medium. This arrangement reduces a volume of the cooking medium that is needed to operate the automatic cooking system with the continuous flow of the cooking medium, which moves food product between the inlet and outlet ends during a cooking process.

In one aspect, the printed heating element is coupled to the cooking vat by being printed on at least one of the bottom wall and the sidewalls of the cooking vat, thereby making the printed heating element and the cooking vat define a unitary, one-piece construction. Each of the other aspects and elements described above can be combined with this embodiment of the automatic cooking system, as will be readily understood from the further description of several examples in the Detailed Description section below.

Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of one or more illustrative embodiments taken in conjunction with the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the general description given above and the detailed description given below, explain the one or more embodiments of the invention.

Embodiments of the invention are directed to automatic cooking systems and methods of controlling a fryer, which reduce and/or optimize the amount of cooking medium required to operate the fryers. Additionally, the invention also provides optimization of heating and use of cooking medium in various fryer designs. To this end, the cooking vat of the system in all embodiments is designed with one or more heating elements that may be provided along an exterior thereof (and/or are provided with a low profile) and multiple lanes for flow of cooking medium and food products, thereby reducing the total volume of retained cooking medium used in the cooking process. Moreover, the use of continuous oil flow and filtration in combination with the new profiles of the lanes in the cooking vat reduce or remove altogether the need to discard used oil when a periodic top off with new oil/cooking medium is required. By improving the flow characteristics and uniform heat transfer into the cooking medium in the automatic cooking system, the embodiments described herein help minimize use and waste of cooking medium and therefore operate more efficiently than conventional fryer designs.

With reference to <FIG>, a first embodiment of the automatic cooking system <NUM> of the current invention is shown in further detail. The system <NUM> includes a cooking vat <NUM> with one lane <NUM> for cooking medium and food product movement, but it will be appreciated that more than one of the lanes <NUM> may be provided in larger versions of the cooking vat <NUM>. The cooking vat <NUM> is shown empty in these Figures. The cooking vat <NUM> includes a pump (not shown) and an oil recirculation system (not shown except for inlet and outlet pipes <NUM>, <NUM> extending from the cooking vat) to generate a continuous flow of cooking medium from an inlet end <NUM> of the cooking vat <NUM> to an outlet end <NUM> of the cooking vat <NUM>. Food products move from portion to portion along the lane <NUM> of the cooking vat <NUM> because of the cooking medium flow, with control of the food product movement provided by the series of gates <NUM> shown in <FIG>. The gates <NUM> are perforated and otherwise function in a similar manner as locks on a river. Thus, the food products can be retained in the heated cooking medium for a time sufficient for fully cooking the food products, and then the food products can be removed from the outlet end <NUM> of the cooking vat <NUM> at the completion of the cooking cycle.

As shown in <FIG>, the lane <NUM> of the cooking vat <NUM> in this embodiment is generally rectangular in cross-section, having a bottom surface <NUM> (also referred to as the "bottom wall" in this and other embodiments) that is <NUM> inches wide between the corners of the cooking vat <NUM>, in one example. To reduce the amount of cooking medium volume within the cooking vat <NUM>, the heating elements <NUM> are provided on the exterior of the cooking vat <NUM>. The heating elements <NUM> include a rod heater <NUM> cast into an aluminum bar <NUM> (or block), which is then coupled in face-to-face abutting contact with the bottom surface <NUM> of the cooking vat <NUM>. The heating elements <NUM> therefore transfer heat energy by conduction through the cooking vat <NUM> and into the cooking medium. By placing the heating elements <NUM> along an exterior of cooking vat <NUM>, the cooking medium and food products do not need to flow around the heating elements <NUM> and turbulent flow is reduced/avoided, which reduces oxidation of the cooking medium and thereby improves cooking medium lifespan.

In the example shown with a <NUM>-inch wide lane, a heating element configured to output <NUM> to <NUM> kW was sufficient in testing results to heat the cooking medium in the cooking vat <NUM> to an operating temperature of at least <NUM>°F and maintain the cooking medium at that temperature through multiple cooking cycles of food products. The large contact surface between the cast bar <NUM> of the heating elements <NUM> and the bottom surface <NUM> advantageously generates a uniform heat transfer and temperature in the shallow pool of cooking medium within the cooking vat <NUM>. The exemplary cooking vat <NUM> shown in this embodiment requires approximately <NUM> pounds of cooking medium per lane <NUM>, to provide an oil depth of <NUM> inches, which provides desirable flow of batches of food products (of approximately <NUM> pounds) from gate to gate <NUM> when the cooking medium is circulated using the oil recirculation system. Likewise, this embodiment of the automatic cooking system <NUM> reduces oil use compared to conventional fryer designs, while also improving oil life, e.g., the total length of time or number of cooking cycles that can be performed before cooking medium replacement is required. The reduced oil volume is achieved at least in part by positioning the heating elements <NUM> on an exterior surface of the cooking vat <NUM>.

A four-lane cooking vat of a second embodiment of the automatic cooking system <NUM> is shown in <FIG>. Each of the <NUM>-inch wide lanes <NUM> from the first embodiment is effectively replaced by two of the lanes <NUM> in the cooking vat <NUM> shown in <FIG>. To this end, each lane <NUM> is about <NUM> inches wide at the top opening thereof, and the cross section of the lane <NUM> is modified to have chamfered corner surfaces <NUM> at the bottom to provide a hexagonal shape and a narrowed bottom surface <NUM> that is about <NUM> inches in width. In addition, the bottom surface <NUM> of the lanes <NUM> are angled upwardly along at least a portion of the length from an inlet end <NUM> of the cooking vat <NUM> to an outlet end <NUM> of the cooking vat <NUM>, most clearly shown in <FIG>. The bottom surface <NUM> is angled upwardly along an entire length of the lane <NUM> in the illustrated embodiment. The oil, which levels out due to gravity, is therefore deeper at the inlet end <NUM> to assure full food product coverage when the food products are initially placed into the cooking vat <NUM>. The shallower depth at the outlet end <NUM>, where the cooked food products are removed for finishing at a packaging zone outside the cooking vat <NUM>, advantageously increases oil flow velocity towards the plumbing of the oil recirculation system. These revisions to the cooking vat <NUM> result in oil volume of about <NUM> pounds per lane <NUM>. This is an improvement of oil volume use (<NUM> lanes use <NUM> pounds of cooking medium as compared to <NUM> pounds in the first embodiment). Thus, the cooking vat <NUM> and lanes <NUM> in the second embodiment improve oil life span by pulling off an amount of oil volume approaching a <NUM>% top off volume per hour of operation, while also significantly reducing the total oil volume needed within the cooking system <NUM>. Like the first embodiment, the cooking vat may also achieve reduced use of cooking medium volume by placing heating elements <NUM>, <NUM> externally to the cooking vat.

Moreover, the flow characteristics of the cooking medium and the food products are improved thanks to the design of the lanes <NUM> of the cooking vat <NUM>. The angled bottom surface <NUM> and the chamfered corner surfaces <NUM> at the bottom of the lanes <NUM> help avoid impeding cooking medium flow in a manner that would generate turbulence in the cooking medium that can increase oxidation of the oil (reduces oil life span) while also improving reliability of flow of food products from gate to gate (gates not shown in these views). The generally increasing velocity of oil along the length of each lane <NUM> also helps assure reliable food product movement from gate to gate. The heating elements <NUM>, <NUM> are once again provided outside the interior of the cooking vat <NUM> to improve flow characteristics and avoid generation of turbulence in the cooking medium. Thus, the second embodiment of the automatic cooking system <NUM> provides several functional advantages, including improved oil life span, reduced oil volume use, and better flow of food products between inlet and outlet ends <NUM>, <NUM> of the cooking vat <NUM>.

As initially described above, the heating elements of the automatic cooking system according to some embodiments are designed to be heater rods cast in aluminum bars or blocks that are coupled to the bottom surface(s) of the lanes defining the cooking vat, to thereby provide uniform heating of the cooking medium via conduction through the cooking vat walls. As set forth below, alternative types of heating elements such as printed heating elements with a low profile may also be used in accordance with this invention. Regardless of the design chosen, the heating elements may be positioned and configured in various manners, some examples of which are shown in <FIG> in association with the second embodiment of the automatic cooking system.

<FIG> and <FIG> show two different configurations of heating elements <NUM> in association with the second embodiment of the automatic cooking system. To this end, the cooking vat <NUM> of this cooking system <NUM> includes four parallel lanes <NUM>, and <FIG> shows one configuration for heating elements <NUM> along the bottom surfaces <NUM> of the cooking vat <NUM>. Larger size heaters 72a are positioned across two or more of the lanes <NUM> adjacent the inlet end <NUM> of the cooking vat <NUM>, while smaller size heaters 72b are positioned on each lane <NUM> individually adjacent the outlet end <NUM> of the cooking vat <NUM>. The combination of larger and smaller heaters 72a, 72b collectively engages with a substantial majority (e.g., <NUM>% or more) of the surface area along the bottom surfaces <NUM> (the about <NUM>-inch-wide surfaces) of each lane <NUM> of the cooking vat <NUM>, thereby enabling the uniform heat transfer desired and needed to maintain the cooking medium at operating temperatures of <NUM>°F or higher. That arrangement of engagement with a large amount of surface area on the lanes <NUM> is maintained in each of the examples shown.

Turning to <FIG>, another configuration of the heating elements <NUM> is shown. Each lane <NUM> of the cooking vat <NUM> includes a single elongated heating element <NUM> connected to the about <NUM>-inch wide bottom surface <NUM> thereof in this embodiment. The heating element <NUM> follows the angling of this bottom surface <NUM>, as described above in connection with the second embodiment of the system. Such an embodiment may be used to individually control the lanes <NUM> when such individual control is desired (e.g., when fewer than the maximum number of lanes <NUM> may be used in operation of the cooking system <NUM>). As will be understood, this and other embodiments of the cooking system <NUM> may use heating elements <NUM> that include rod heaters in cast blocks of aluminum, or printed heating elements, or other known designs for conducting heat into the cooking vat <NUM>.

In <FIG>, a further configuration is shown of a cooking system <NUM>, which includes similar elements as one of the lanes <NUM> in the cooking vat <NUM> shown in <FIG> (identical reference numbers are used where elements are unchanged from the embodiment described above). This cooking system <NUM> includes heating elements <NUM> mounted on the exterior of the cooking vat <NUM> along both the bottom surface <NUM> and the chamfered corner surfaces <NUM> at the bottom end of each lane <NUM> of the cooking vat <NUM>. The heating elements <NUM> of each configuration may be coupled to the cooking vat <NUM> using various methods, including but not limited to, welded studs on the bottom surface <NUM> of each lane <NUM>, and/or springloaded clamps. Regardless of the configuration and coupling mechanism chosen, the heating elements <NUM> provide uniform heating and temperatures within the cooking medium during cooking operations, and the heat transfer and temperature uniformity is further improved by the continuous flow of cooking medium through the cooking vat <NUM> and through the oil recirculation system.

As described above, although the external heating elements shown and described in connection with the embodiments of the automatic cooking system shown in <FIG> through 6D is a clamped-on or bolted-on aluminum block heater, alternative designs of heating elements can also be used in these embodiments. In this regard, the heating elements used with an electric fryer such as these automatic cooking systems can instead be defined by printed heating elements such as the thick film conduction heaters available commercially from supplies such as Watlow of St. For example, the "<NUM> stainless steel thick film conduction heater" available from Watlow includes a resistor circuit trace embedded in the material printing process into one or more dielectric glass layers, which may also be incorporated on one or more <NUM> stainless steel substrates, and the heater can also include additional layers like a mica insulator along one side to ensure heat energy is transferred from the heater into the element to which the heater is directly connected. The thick film conduction heater defines a low profile based on a small thickness when fully printed, while allowing for efficient heating of elements that the thick film conduction heater is directly applied to.

Further examples showing one or more printed heating elements as described above in connection with a fryer are shown in the embodiments of <FIG>. More specifically, these Figures illustrate the printed heating elements in combination with an automatic cooking system including one or more lanes for moving food product and cooking it as the food product moves between gates and stations, as set forth in the embodiments described above.

In <FIG>, several views are provided of a cooking vat <NUM> for another embodiment of an automatic cooking system, this one defining a single lane for food product movement during the cooking process. As with previous embodiments, the cooking vat <NUM> has a profiled and/or angled bottom wall <NUM> which allows for reduction in oil volume level as the food product moves along the length of the cooking vat <NUM>, with increased oil flow velocity towards the end of the fryer. More specifically, the bottom wall <NUM> may include a first portion 102a along an inlet end <NUM> and a second portion 102b along an outlet end <NUM>, each portion being angled slightly upwardly from horizontal along the movement direction of food product traveling between the inlet end <NUM> and the outlet end <NUM>. The first and second portions 102a, 102b are connected in this embodiment by a transition portion 102c of the bottom wall <NUM> that is angled from the orientation of the other two portions 102a, 102b. Such a configuration of the bottom wall <NUM> may be desirable to achieve certain flow characteristics along the lane defined by the cooking vat <NUM>. For example, the cooking vat <NUM> may transition from a generally flat bottom along the first portion 102a of the bottom wall <NUM> to a bottom with chamfered corners (or sidewall portions) proximate the edges of the bottom wall <NUM> along the second portion 102b, see <FIG>, and in such embodiments, the flow of cooking medium and food products is enhanced by the change in shape of the cooking vat <NUM> towards the outlet end <NUM> (the transition portion 102c helps accommodate this variation of shape of the cooking vat <NUM>). It will be understood that this is but one example of the shape of an elongated cooking lane defined by the cooking vat <NUM>, and other shapes and profiles may be used without departing from the scope of the invention.

In this embodiment, printed heating elements <NUM> are applied to the bottom wall <NUM> of the cooking vat <NUM>, and specifically, applied along the two large generally rectangular sections of that bottom wall <NUM> defined by the first and second portions 102a, 102b. The thin profile or thickness of the printed heating elements <NUM> make these elements difficult to see in the side views shown at <FIG>. Nevertheless, each of the printed heating elements <NUM> includes a temperature sensor <NUM> mounted directly on the surface of the heating element <NUM>, with a control wire <NUM> (shown in partial form) leading to the system controller for the automatic cooking system. For example, each temperature sensor <NUM> may be an RTD sensor, and the temperature sensors <NUM> are thus positioned to detect the heater temperature defined by the printed heating elements <NUM>. By controlling the heater temperature to remain below certain thresholds, the controller can assure that the heating elements <NUM> never rise above a temperature at which a dry fire could start. Thus, improved safety in operation is achieved by this design using the printed heating elements <NUM> with the directly mounted temperature sensors <NUM>.

As also shown in <FIG>, the printed heating elements <NUM> define an internal resistor circuit trace <NUM> that is used to produce the heat energy for the cooking medium in the cooking vat <NUM>. The resistor circuit trace <NUM> within the printed heating elements <NUM> is terminated in this design at a series of threaded studs <NUM> which are connected by wires <NUM> (partially shown) to a power source. The control of the heating elements <NUM> through the threaded studs <NUM> allows the design to remain low profile, limiting the space required for mounting the heating elements <NUM> to the cooking vat <NUM>. As noted above, the printed heating elements <NUM> may be directly coupled to the bottom wall <NUM> of the cooking vat <NUM> using adherence, welding, clamp connections, or the like, and the heating elements <NUM> contain layers or internal features that guide heat energy from the heating elements <NUM> into the cooking vat <NUM> and the cooking medium flowing therein. Thus, this embodiment of the cooking vat <NUM> is both space-efficient and energy-efficient because losses of thermal energy are minimized by the arrangement of elements and their internal designs. As set forth above, the external mounting of the heating elements <NUM> avoids the need to place these elements inside the cooking vat <NUM>, which therefore reduces the overall cooking medium volume that must be used in this automatic cooking system. Oil life may also be improved when placing the heating elements <NUM> out of direct contact with the cooking medium, in some implementations.

With reference to <FIG>, another cooking vat <NUM> in accordance with another embodiment of an automatic cooking system of this invention is shown in detail. This embodiment of the cooking vat <NUM> includes a shape and profile largely similar to the cooking vat <NUM> of the previous embodiment, and as such, similar reference numbers are used on elements that are essentially unchanged from the previous embodiment. These elements include the bottom wall <NUM> (with first portion 102a, second portion 102b, and transition portion 102c), the inlet end <NUM>, the outlet end <NUM>, the printed heating elements <NUM>, the temperature sensors <NUM>, and the resistor circuit traces <NUM>, among other elements. The cooking vat <NUM> does not include angled sidewall portions or chamfered corners along the second portion 102b of the bottom wall <NUM>, and as such, the total planar surface area defined by the first and second portions 102a, 102b of the bottom wall <NUM> are slightly larger in size than in the previous embodiment in <FIG>. The printed heating elements <NUM> are modified only in this embodiment to be larger in size, thereby being engaged with and covering a larger overall surface area of the first and second portions 102a, 102b of bottom wall <NUM>. This design allows for more heat energy to be delivered efficiently into the cooking vat <NUM> and the cooking medium and food product flowing therein, e.g., providing uniform heating. Regardless, the same benefits of a low profile and reduced oil volume use are achieved by this alternative embodiment.

In <FIG>, the termination of the resistor circuit traces <NUM> of the heating elements <NUM> at threaded studs <NUM> is shown in greater detail. The wires <NUM> delivering electrical energy to cause the resistor circuit traces <NUM> to produce heat energy are shown connected in position by the threaded studs <NUM>. In this regard, a controller or power source of the automatic cooking system controls the amount of heat energy being produced via the energy provided by the wires <NUM>, and such control may be based on temperature sensor readings from within the cooking vat <NUM> as well as based on signals from the temperature sensors <NUM> mounted directly on the heating elements <NUM>, thereby enabling the controller to avoid heating the heating elements <NUM> to a temperature that would risk a dry fire condition. Consequently, this embodiment of the cooking vat <NUM> provides many of the same technical advantages as described in association with other embodiments. It will be understood that the particular size and shape of the cooking vat <NUM> and the heating elements <NUM> may be modified in other embodiments, including, for example, having multiple lanes in adjacent relation for the automatic cooking system, and mounting the heating elements <NUM> to additional/alternative surfaces like the sidewalls.

<FIG> illustrates an alternative embodiment of a printed heating element <NUM> that may be used with any of the embodiments of the automatic cooking systems described herein. As shown in <FIG>, the printed heating element <NUM> is square in shape and is configured to cover a substantial portion of a bottom surface of a cooking vat or portion thereof, so as to thereby provide generally uniform heating of the cooking vat and the cooking medium therein. The printed heating element <NUM> again includes a resistor circuit trace <NUM> terminated at threaded studs <NUM> connected to power supply wires <NUM>. One or more of these printed heating elements <NUM> may be combined to cover the external surfaces of the cooking vat of the automatic cooking systems of this invention.

It will be appreciated that the heating elements may be repositioned or reconfigured in other embodiments of the invention depending on the needs and desires of the end user. In one example, the printed heating elements may be coupled to side surfaces of a cooking vat as well as the bottom surface, as was alluded to above in the example with clamped plate heaters. The external mounting of the heaters is configured to provide uniform heating while allowing for reduced oil volume use when operating automatic cooking devices using elongated lanes defined by the cooking vats and cooking medium and food product flow during the cooking process.

In still further alternative embodiments using the low profile printed heating elements, the printed heating elements may also be located inside the cooking vat, but the low profile and small thickness of these heating elements continues to allow for minimized oil volume use even when placed within the cooking vat (e.g., the low profile provides minimal disruption to cooking medium flow and thus produces less turbulence that can also reduce oil lifespan). Additional modifications to the embodiments shown and described herein with the external mounted heating elements will be understood by those skilled in the art when using these heaters internally, such as connecting the temperature sensor and control wires to the heater when submersed within a cooking medium. The various designs of the automated cooking system and other fryers using printed heating elements achieve advantages and additional functionalities (such as increased safety and reduced risk of dry fires) over the known fryer designs.

Claim 1:
An automatic cooking system (<NUM>, <NUM>, <NUM>) for frying food products, comprising:
a cooking vat (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to hold a cooking medium and to receive food product, the cooking vat defining at least one elongated lane (<NUM>, <NUM>, <NUM>) extending between an inlet end (<NUM>, <NUM>, <NUM>, <NUM>) where the food product is inserted into the cooking vat and an outlet end (<NUM>, <NUM>, <NUM>, <NUM>) where the food product is removed from the cooking vat, wherein each lane of the cooking vat includes a bottom wall and sidewalls extending along the lane; and
an oil recirculation and filtration system (<NUM>, <NUM>) in communication with the inlet end and the outlet end of the cooking vat, the oil recirculation and filtration system configured to generate a continuous flow of the cooking medium from the inlet end to the outlet end;
characterized by:
a heating element coupled to at least one of the bottom wall and the sidewalls of the cooking vat, the heating element comprising at least one printed heating element (<NUM>, <NUM>) directly coupled to the cooking vat so as to transfer heat by conduction to uniformly heat the cooking medium;
a controller operatively coupled to the oil recirculation and filtration system and to the heating element; and
a temperature sensor coupled directly to the heating element and configured to measure a heater temperature of the heating element and communicate the heater temperature to the controller, wherein the controller controls the heating element to prevent the heater temperature exceeding a temperature that may lead to a dry fire condition.