MXPA99004380A - Heating control system for a gas fryer - Google Patents

Abstract

The present invention provides a fryer system including a fryer having a vat (12), for containing shortening therein, a heat exchanger (14) disposed within the vat (12), a heating mechanism for supplying heat to the heat exchanger (14), and a control mechanism for controlling the heating mechanism. The control means repeatedly cycles the heating mechanism between an off condition and an on condition during a melt mode of operating and maintains the heating mechanism in an on condition during a cook mode of operating. A manual switch is provided for switching the control mechanism from the melt mode of operation to the cook mode of operation. A prevention mechanism is also provided for preventing the control means from entering the cook mode of operation, and thereby maintaining the heating mechanism in an on condition, prior to actuation of the manual switch.

Description

HEATING CONTROL SYSTEM FOR A GAS FRYER TECHNICAL FIELD The present invention relates to a fat fryer at the bottom, and more particularly, to a fat fryer at the bottom which has a "safe melt" mode for melting solid butter, a safe mode of shutdown failure, and one of "safe filtering" that, separately or in combination, helps to avoid overheating of the heat exchanger and the components of the fryer.

BACKGROUND OF THE INVENTION Bottom fat fryers, or gas fryers, are used commercially in restaurants, corporate kitchens, and fast food establishments to cook a variety of food products, such as potato chips, fish, fried chicken and Similar. The gas fryer should not only accommodate the individual heating requirements of each particular food product, but should also maintain the consistency and uniformity of taste and texture during the cooking process. The food product is cooked by completely submerging it inside a trough or tank that is filled with oil or hot butter. The oil is typically heated using a heat exchanger having a recirculating flow of heated gas that is forced or extracted through passages or tubes that are in thermal communication with wall portions of the cooking tundish. A gas burner is provided to heat the gas circulating inside the heat exchanger. In U.S. Patent No. 5,417,202, assigned to the America's Favorite Chicken Company (AFC), the heat exchanger utilizes a combination of horizontal, downward, horizontal, and full mixing transfer tubes connected thereto in order to ensure that there is Complete mixing of the heat transfer fluid passing through the heat transfer tubes. This is also achieved by placing the heat exchanger, including heat transfer tubes and mixing plenums, inside the tank or tundish that is filled with lard or other cooking means. Examples of the prior art systems are shown in U.S. Patent No. 4,481,873, to Keating; 4,848,317 for Prudhomme et al., 4,898,151 for Luebke et al., And 5,050,582 for Almond et al. In those prior art systems, it is difficult to safely melt solid butter or frozen shortening because the heat exchanger inside the fryer trough will overheat unless it is completely surrounded by a liquid, ie, molten butter. . When the solid butter melts around the heat exchanger tubes and leaves a hollow air cavity, it allows the temperature of the tubes to become excessive. Therefore, without the action of the melted butter as a conductive medium around the tubes of the heat exchanger, the tubes quickly reach an excessively high temperature which can cause permanent damage to them, as well as damage to the fryer trough, such as weld cracking where the heat exchanger is attached to the tundish. If the butter is spilled through damaged solder, it may fall where it would be exposed to the burner flame and could result in a fire. In addition, partially exposed heat exchanger tubes that overheated can heat the surface of the butter that passes the ignition point and cause a fire in the tundish. The resolution of this problem is also involved with the damages included with the first fusion of solid butter in a different location away from the tundish and then try to pour the hot butter into the trough of the fryer. Due to the inherent damage of severely burned employees, this solution to the problem usually has no follow-up in the industry. Other attempts to solve the problem include previous gas fryers that have a designated melting cycle that turns the heat on and off in a repeated cycle, ie a work cycle, until the butter reaches a predetermined temperature as detected by a sensor and then automatically applies all the energy to the fryer. While this type of melting cycle can help prevent singeing of lard and extends the shelf life of the lard by slower heating of the lard, it does not prevent premature operation of the fryer in a heat cooking mode total. In addition, because other considerations determine that the sensor is located below the top of the heat exchanger, the butter that reaches a predetermined temperature at a sensor location does not guarantee that a sufficient quantity of butter has been melted to allow the tundish the fryer will resist the heat of all the energy. In such cases when the solid shortening has not sufficiently melted to substantially submerge the heat exchanger, the automatic application of all the energy results in overheating of the fryer trough and, most likely, destroys it. Overheating of the heat exchanger also creates a problem during certain operations of the fryer trough. For example, when the melted butter is drained from the fryer trough for periodic filtering, it is important that the energy to the heat exchanger is turned off, and that energy is not restored until after the molten butter has replenished. trough. However, in practice, the drain valve may inadvertently not be closed in the tundish after the filtering operation and the molten butter are emptied through the drain hole instead of relieving the tundish. Therefore, when the heat exchanger is restored to the heat exchanger, the tundish is emptied and overheated. This type of problem is further compounded by the prior art fryers that summarize the operation in its last mode of operation before the power is interrupted. For example, if a fryer was operated in a full heat cooking mode when the power was turned off or otherwise interrupted, when the energy was restored the fryer would start the operation in the total heat cooking mode. However, in the intermediate, while the energy was interrupted, the shortening may have been drained from the tundish of the fryer or, depending on the time of the power cut, the shortening may have solidified again inside the tundish. In any case, the initial application of all the heat will cause the heat exchanger to overheat and damage the trough.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, in view of the foregoing, it is an object of the present invention to provide a gas fryer having a "safe melting" mode that significantly reduces the potential for damage to the fryer tundish and / or the ignition of a fryer. fire due to overheating of the heat exchanger, and that eliminates the problems and disadvantages that occur in the prior art as described above. It is a further object of the present invention to provide a fail-safe energy deactivation for the gas fryer to ensure that the fryer begins operation in the fusing mode as long as it is deactivated or otherwise power is interrupted. . It is also an object of the present invention to provide a gas fryer that has a "safe-filtration" process that reduces the potential for damage to the fryer trough after the filtering process due to the lack of butter in the tundish and which also eliminates the problems and disadvantages found in the prior art. These objects are achieved by the fryer system of the present invention having a fryer including a tundish containing butter therein, a heat exchanger placed inside the tundish, a heating mechanism for supplying heat to the heat exchanger, and a mechanism of control to control the heating mechanism. The control mechanism repeatedly cycles the heating mechanism between an off condition and an ignition condition during a melting operation mode and maintains the heating mechanism in an ignition condition during a cooking operation mode. A manual switch is provided to switch the control mechanism from the fusing operation mode to the cooking operation mode. The control mechanism is prevented from entering the cooking operation mode and, in this way, keeps the heating mechanism in an ignition condition, before the operation of the manual switch. The tundish of the fryer contains a selected amount of butter so that the shortening within the tundish in a substantially melted state is at least sufficient to substantially cover the heat exchanger and thereby define a safe level of shortening. The manual switch is operated after the shortening has sufficiently melted to reach the safe level. The control mechanism is also required to operate in the fusion mode whenever the energy is initially supplied to it after a power interruption. In a preferred embodiment of the present invention, the control mechanism further includes a sensor for detecting the temperature of the melted butter within the trough and creating a signal when the detected temperature reaches a predefined value that differentiates between the ambient temperature and that of the melted butter. The manual switch can only be activated after the sensor reaches the predefined value. In a further preferred embodiment of the present invention an energy switch having an ignition position and an extinguishing position is provided for turning on and off the power, respectively, for the control mechanism. A drain switch is also provided to apply power to the control mechanism when the drain switch closes and interrupts power to the control mechanism when the drain inter- rupter is opened. The drain switch closes when a trowel drain valve closes and opens when the trough drain valve is open. Therefore, the drain switch thus ensures that the trough drain valve closes before applying power to the control mechanism. This, in turn, ensures that the controller will return to the merge mode safe by default after drainage is opened. A return switch is provided additional to apply energy to a filter and the return system when the return switch is closed and interrupts the energy to the filter and the return system when the return switch is open. The return switch closes when the power switch is in an off position and the return switch is open when the power switch is in an on position. So, the return switch means ensure that the energy is not being applied to the heating mechanism before the completion of the filtering procedure.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing description and other objects, advantages and features of the present invention will be more fully understood and appreciated by reference to the specification and accompanying drawings, in which: FIG. 1 is a perspective view of a heat exchanger placed in a gas fryer trough according to the present invention; Fig. 2 is a schematic top plan view thereof; Fig. 3 is a schematic view in lateral elevation thereof; Fig. 4 is a schematic view in extreme elevation thereof; Fig. 5 is a flow diagram according to a first embodiment of the present invention; Fig. 6 is an electrical diagram thereof; Fig. 7 is a flow diagram according to a second embodiment of the present invention; Fig. 8 is an electrical schematic thereof; Fig. 9 is a flow chart according to a third embodiment of the present invention; Fig. 10 is an electrical schematic thereof; Fig. 11 is a schematic top plan view of the drainage system according to the present invention; Fig. 12 is a partial cross-sectional view illustrating the positioning of the handles and micro switches during a normal mode of operation; Fig. 13 is a partial cross-sectional view illustrating the positioning of the handles and micro switches during a draining mode; and Fig. 14 is a partial cross-sectional view during a tundish filling mode.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Referring to Fig. 1, a gas fryer according to the present invention is generally shown by reference numeral 10. The gas fryer preferably includes a plurality of troughs 12 for holding butter, oil or other cooking means, a heat exchanger 14 for heating the butter in each trough 12, a burner 1 1 for heating the fluid flowing through the heat exchanger, and a blower motor 13 for extracting or forcing the heated fluid through the heat exchanger 14. Due to its efficiency and economic availability, the heat exchange fluid generally used in the present invention and gas fryers of the prior art is air; however, other gaseous or liquid fluids may also be considered as allowed by their development. In the preferred embodiments of Figs. 1-4, the heat exchanger 14 includes a plurality of heat transfer conduits 16, 18, 20, 22, 24, 26, 28, 30 and two mixing plenums 32, 34. The direction of displacement of the heated fluid through the heat exchanger 14 is illustrated schematically in Fig. 2 to show the heated fluid entering the trough by means of the inlet heat transfer tubes 16, 18, 20, mixed in the plenum 32 passing through the heat transfer tubes 22, 24, 26 , mixed in a plenum 34, and exiting after the tundish through the outlet heat transfer tubes 28, 30. A further description of the heat exchanger is provided in the aforementioned US Patent No. 5,417,202, the content of which is incorporated herein by reference. In a preferred embodiment of the present invention, gas fryer 10 includes a trough 12 having internal dimensions of 50.8 x 50.8 cm, 45.72 x 45.72 cm, or 35.56 x 35.56 cm, although any other desired dimensions could also be used. The heat exchanger 14 is therefore correspondingly sized to be placed inside the tundish 12. For example, for a 50.8 cm trough, the heat transfer tubes 16, 18, 20, 28, 30 are approximately 42.96 cm long and the heat transfer tubes 22, 24, 26 are approximately 35.30 cm. The plenum 32 is positioned approximately 2.54 cm from the side wall 38 and the plenum 34 is positioned approximately 2.54 cm from the side wall 36. The center lines of the heat transfer tubes 1630 are placed approximately 3.81 cm from the opposite lateral pairs of trough 12, and the center lines of the remaining heat transfer tubes are placed approximately 5.39 cm apart from one another or, in the case of tubes 22 and 24, placed at 5.39 cm from the central line of drainage 40. Similarly, for a trough of 45.72 cm. the heat transfer tubes 16, 18, 20, 28, 30 are approximately 37.84 cm long and the heat transfer tubes 22. 24, 26 are approximately 30.22 cm long. As in the 50.8 cm trough embodiment, the plenum 32 is positioned approximately 2.54 cm from the side wall 38 and the plenum 34 is positioned approximately 2.54 cm from the side wall 36. The center lines of the transfer tubes of heat 16, 30 are placed approximately 3.81 cm In from opposite side walls of the tundish 12, and the center lines of the remaining heat transfer tubes are placed approximately 5.39 cm from each other. In a further embodiment of the invention, the heat exchanger is used in a trough having dimensions of 35.56 x 35.56 cm. The heat exchanger is therefore dimensioned correspondingly within the smaller tundish. The dimensions of the heat transfer tubes are also reduced to accommodate the smaller trough dimensions. For example, the heat transfer tubes are approximately 27.68 cm and approximately 20.06 cm long. A plenum is placed approximately 2.54 cm from the side wall and a plenum is placed approximately 2.54 cm from the other side wall. The center lines of the heat transfer tubes are collated approximately 4.06 cm in from the opposite side walls of the tundish, and the center lines of the remaining heat transfer tubes are placed approximately 5.39 cm apart. the other. Preferably, the heat exchanger and the tundish are made from stainless steel or any other desirable material capable of withstanding the significant heat. Stainless steel is preferably used because it does not react chemically with food or butter. Likewise, it does not flake or provide foreign matter that could attack the food, and it resists rough cleaning. Stainless steel can be formed, welded and ground to prevent food entrapment while providing optimum geometry for heat transfer. Other special coatings and processes may allow other metals or substrates to acquire those properties and may be subjected to other forms required for flow, containment and cooking, but not other materials that are currently in common use to achieve those results. For the above-described embodiments of the present invention, the heat exchanger 14 is placed on the bottom surface of the tundish at approximately 7.62 cm to 12.7 cm. This placement of the heat exchanger inside the trough 12 creates a "cold zone", that is, the temperature of the shortening under the surface of the heat exchanger (approximately 93.3 ° C) is significantly lower than the temperature of the hot shortening on the heat exchanger ( approximately 176.6 ° C). this construction prevents the food particles that fall inside the butter from settling in the bottom of the tundish and continuing cooking, thereby increasing the shelf life of the lard, oil or other cooking medium inside the tundish. With reference to Fig. 3, a probe 42 is preferably positioned within the trough 12 below the level of "safe" butter represented by the line SL. The probe 42 includes a sensor that determines when the melted butter has reached a predetermined temperature. The preferred sensor can be a thermocouple, thermistor or resistance temperature sensing device (RTD). Alternatively, in a less preferred embodiment, a bulb and capillary sensor that only reacts at a temperature could be used for cooking and a melting cycle device that has no sensor that could be used for melting, thereby relying on a completely visual decision to exit from the mode of fusion with the switch that is achieved by a locking relay. Other devices that have properties that change in known ways with temperature can be used to detect the output of the fusion ability and cooking control. In a preferred embodiment, the predefined temperature is about 57.2 ° C, which corresponds to a temperature which will indicate the presence of a heated melted butter instead of just natural air and thus allows it to exit the melting mode. The fusion cycle by nature comprises more than heating the butter. A higher pre-set temperature would mean longer start times to reach the cooking mode. A lower predefined temperature, on the other hand, may not ensure that the shortening has reached the viscosity necessary for adequate heat transfer through the butter flow. After reaching the predefined temperature and leaving the melting mode, the heating times are faster through the total heat-up of the heat exchanger. Usually the probe 42 is placed below line SL so as not to interfere with parril the and baskets that rest on the heat exchanger 14. Due to the preferred placement of a probe below the highest point of the heat exchanger, when a probe was used with fryers of the prior art was not an infallible mechanism for determining the safety of the fusion operation mode. That is, the melted butter that has a temperature higher than the predefined value could exist at the level of the probe without the melted butter covering the entire heat exchanger. Therefore, by automatically switching the mode of fusion in response to a signal from a probe, the heat exchanger tubes could overheat and cause the shortening to turn on, thereby destroying the fryer pan and the heat exchanger. To prevent this from occurring in the present invention, an additional operation manual is required by the user to directly check the tundish to see if the heat exchanger is covered with the melted butter, and if it is, to activate a switch. to exit the fusion mode of the fryer. I have reference to Figs. 9 and 10, in a first preferred embodiment of the present invention, a cooking computer 44 is used to ensure that the heating system that starts in the firing mode always that the energy is initially supplied to the system. . That is, s henever the energy is ed interrupted or otherwise disconnected, a switch or push selector switch 64 must be actuated first, to connect power to the system and switch PowerOn DI DO / OFF 66 should be driven later to return the cooking computer 44 to the operation. Whenever the cooking computer starts the operation, it will start in the safe fusion operation mode. The safe melting mode of the present invention is a pulsed on-off duty cycle when the gas is supplied to the burner at predetermined intervals. Typically, the gas will be activated for approximately eight seconds and then deactivated for twenty-eight seconds, before turning it on once more. Using the pulse cycle to initially heat the solid butter, the butter melts gradually, but without overheating the trough or heat exchanger. During the safe melting mode of the present invention, the temperature of the heat exchanger can be slowly raised to a stable state temperature not exceeding about 260 ° C. this temperature is below the point of ignition of the butter (typically 287.7 ° C) and is well below the temperatures that damage the stainless steel (typically 537.7 ° C), that is, the thermal fatigue value of the heat exchanger. These design considerations are selected when an animal or vegetable derivative is the preferred solid shortening to fuse and the stainless steel is used for the manufacture of the heat exchanger and the tundish.; however, it should be apparent to one skilled in the art that peanut oil, Olestra® or other solid shortenings were used to have several ignition points or if other metals or materials were used for the construction of the fryer, the temperature Maximum heating of the heat exchanger tubes would vary accordingly. When the probe 42 detects that the melted butter has reached the temperature predefined in the present invention, a signal can be made to the user of the fryer. This signal may be audible, such as a tone, or visible such as a light on a control panel of the cooking computer 44. In any case, the heating system in the safe fusion mode even after the probe detects the predefined temperature. In order for the fryer to be operated in a cooking mode, when the gas is continuously driven, the user must manually trigger an output fusing switch 46. Alternatively, the computer can display the actual temperature of the melted butter and this display can be periodically monitored so that the user is aware of the actual temperature and can determine the appropriate time to operate the output fusing switch 46. Before doing so, the user is expected to visually examine the level of the butter melted into the tundish and determine whether or not it has reached the level of safe butter, noted by line S L. If the melted butter has not reached the SL line, and therefore is not covering substantially all of the heat exchanger, then the system must continue the operation in safe fusion mode until the melted butter completely covers the heat exchanger. On the other hand, if at the moment when the probe signals or the screen indicate that the shortening has reached the predefined temperature, the user inspects the level of butter inside the trough and believes that the shortening is covering substantially all the heat exchanger , then you can manually switch the switch 46 so that the heating system exits the safe melting mode and subsequently operates in a full heat cooking mode. To further protect the trough and the heat exchanger from overheating, the computer 44 is programmed so that it will not allow the user to prematurely exit the safe fusion mode before the temperature detected by the probe is greater than the predefined value. In a preferred embodiment, a drain valve switch 50 is added to ensure that draining of the fryer trough is closed and the molten butter is present inside the tundish before it is possible to operate the fryer in a cooking mode of full heat. The drain valve is routinely opened during the butter filtering process, that is, the butter is discharged from the trough through the drain valve, cycled through a filter pump, and then returned to the trough through a return valve. A filtration process is usually necessary to remove food particles that may have collected at the bottom of the tundish. However, the user of the fryer may not always remember to close the drain valve after the filtration process is completed. Similarly, the drain valve may accidentally open during cleaning or other activities. In the prior art embodiments, once the shortening drained below the safe level represented by the SL line, there would be a fire or other major damage to the tundish and the heat exchanger if the fryer was operated in the heat cooking mode total. Referring also to Figs. 1 -14, the drain valve switch 50 is used to ensure that if the drain valve of the tundish 52 is open (allowing the shortening to exit the tundish and thereby expose the heat exchanger again to a possibility of cold start, the main energy is disconnected to the cooking computer 44 and the heating system is turned off. When the power is subsequently applied, with the drain valve closed, the cooking computer 44 will be in an "off" state and the ON / OFF SWITCH switch 66 must be activated by the user to resume the operation. The only option available to the user is to re-enter secure fusion mode. As described above in detail, the cooking computer 44 will continue to operate in the secure fusion mode until the output fusing switch 46 is activated manually. Consequently, if the drain is accidentally left open after filtering or if it is opened by mistake during the operation of the fryer, the end result is that the energy of the fryer will be disconnected to avoid damage to the tundish and the heat exchanger. In addition, when the power is restored again, and the ON / OFF switch is activated, the fail-safe energy deactivation ensures that the system will be in operation in the safe melting mode to avoid any damage to the trough or the heat exchanger in the case that the level of the butter has decreased below the level of safe butter while the drainage was open. As shown in Fig. 11, the present invention includes a drain valve 52 having a handle 54, a drain valve switch 50, a return valve 56 having a return valve handle 58 and a switch 60 for the filter pump. Fig. 12 illustrates the position of these elements during the cooking mode of normal operation of the fryer. As shown, the return handle 58 is in the closed position, the switch 60 is open, the drain handle 54 is in a closed position, and the drain valve switch 50 is in a closed position. With reference to Fig. 10, the closed position of switch 50 allows power to be supplied to the cooking computer for operation of the heating cycle.

The open position of the switch 60 indicates that the energy is not supplied to the filter pump 62 during the normal cooking operation mode. Similarly, Fig. 13 illustrates the positions of the handles and switches during the drain operation mode. As shown, the return handle 58 is in a closed position, the switch 60 is open, the drain handle 54 is in an open position, and the drain valve switch 50 is in an open position. Therefore, with the drain in an open position, the energy is not supplied to the cooking computer and the damage of the tundish and the heat exchanger that is damaged is eliminated. Prior to filling the tundish, the system can be allowed to cycle the butter through the filtering operation several times in a process known as butter polishing. Thus, the system can operate with draining handle 54 in an open position and switch 60 in a closed position. With reference to Fig. 14, after the tundish is drained and the shortening has been processed through the filter pump 62, it is returned to the trough through the return valve 56. accordingly, in the tundish filling mode, when the shortening is returned to the tundish, the return handle 58 is in an open position, the switch 60 is closed, the drain handle 54 is in a closed position, and the drain valve switch 50 is closed. The pan mode of the pan therefore allows the power to be supplied to the filtering operation (by virtue of the closed switch 60). The power is only supplied to the filter pump, but, when the selector switch 64 is in the "off" position. Therefore, the energy to the computer 44 and the fryer can be disconnected so that the shortening is filtered and returned to the tundish. When the filtering operation is completed and the push switch or selector switch 64 is activated to the "on" position, power is supplied to the cooking computer 44 (under the closed switch 50), which will initiate the operation in the fusion mode when the ON / OFF switch 66 is activated again in the ON position. With reference to Figs. 5 and 6, a simplified embodiment described above includes a melt cycle controller 68 instead of the computer 44 of the first mode. The melt cycle controller 68 is wired to a main power switch 70 so that the switch 70 can be activated to operate the controller 68. In addition, the controller 68 will automatically enter a secure fusion mode, as described in FIG. described earlier, at any time that the power is initially supplied after being turned off or otherwise deactivated. As in the above embodiment, the controller 68 will also not exit the safe fusion operation mode until the output fusing switch 46 is manually operated by the user. Therefore, the controller 68 also prevents damage to the tundish and heat exchanger by requiring additional manual operation of the output fusing switch so that the fryer operates in a full heat cooking mode. Figs. 7 and 8 illustrate a further modification of the second embodiment described above, by the addition of a drain valve switch 50 and the switch 60 for the filter pump. The drain valve switch 50 and switch 60 operate in an identical manner to that described above with reference to the first preferred embodiment. Accordingly, in this mode, the controller 68 is prevented from operating and receiving power when the drain valve 52 is open, i.e., the drain valve switch 50 is open. Likewise, the filter pump 62 only receives the energy to operate when the push switch or selector 64 is in the off position., and when the power is restored to the controller 68 (by virtue of the closed drain valve switch 50), the controller 58 will begin operation in the safe fusion mode. Therefore, damage to the tundish and the heat exchanger is prevented by requiring the drain valve 56 to be closed so that the drain valve switch 50 must be closed, and by requiring the controller 68 to operate in the operation mode. The fusion melt is safe until the user manually activates the salt fusion switch 46. Although the foregoing was described with reference to the particular embodiments, it will be obvious to one skilled in the art that many modifications of the various embodiments are possible. That is, since the controller can be used with and without the drain valve, the cooking computer can also be used with and without the drain valve switch and / or the return valve switch. Furthermore, it will be obvious to one skilled in the art that numerous modifications can be made without departing from the true spirit and scope of the present invention, which will be limited only by the appended claims.

Claims (10)

REIVI N DICACIONES

1 . A fryer system comprising: a fryer including a pan containing butter therein; u a heat exchanger placed inside the trough; heating means for supplying heat to said heat exchanger or; control means for controlling said heating means, the control means repeatedly cycling the heating means between a shutdown condition and an ignition condition during a melting operation mode and maintaining the heating means in an ignition condition during a cooking operation mode; manual switch means for switching said control means from the fusing operation mode to the cooking operation mode; prevention means for preventing said control means from entering the cooking operation mode, and thereby maintaining said heating means in an ignition condition, prior to the actuation of said manual switch means.

2. The fryer system of claim 1, wherein the tundish contains a selected amount of butter, the shortening within said tundish in a substantially melted state which is at least sufficient to substantially cover said heat exchanger and therefore it defines a safe level of butter. The fryer system of claim 2, wherein the manual switch means is operated after the shortening has sufficiently melted to reach said safe level. The fryer system of claim 1, wherein the prevention means further require that said control means operate in the fusing mode whenever the energy is initially supplied to them after a power interruption. The fryer system of claim 4, further comprising energy switch means having an on position and an off position for energizing and de-energizing, respectively, for said control means. The fryer system of claim 5, further comprising switch means for applying energy to said control means when said drain switch means are closed and interrupting the power to said control means when the switch means of drainage are open, said drainage switch means being closed when a drain valve of said tundish is closed and open when the trough drain valve is open, said draining switch means ensuring this so that the drain valve of said tundish is closed before applying the energy to said control means. The fryer system of claim 5, further comprising return switch means for applying energy to a filter and the return system when the return switch means are closed and interrupting the energy to the filter and the system. return when said return switch means are open, said return switch means being closed when the power switch means are in an off position and said return switch means are open when said power switch means are in a switched-on position, said return switch means thus ensuring that the energy is not applied to said control means before applying the energy to the filter and the return system. The fryer system of claim 5, wherein said control means further includes sensor means for detecting the temperature of the molten butter within the tundish and creating a signal when the detected temperature reaches a predefined value. The fryer system of claim 8, wherein said manual switch means can be actuated only after said sensor means reaches said predefined value. The fryer system of claim 9, wherein said control means further includes an on / off switch is operated to the ignition condition. eleven . An operation method of a heating system for a fryer comprising the steps of: placing a quantity of lard inside lard inside a fryer trough; apply energy to the fryer system by operating a main power switch; applying energy to a control means for the heating system, the control means that initiate the operation of the heating system in a melting mode; observe the level of the butter inside the trough; and operating an outlet fusing switch when the observed level of the shortening is sufficient to substantially cover a heat exchanger placed inside the fryer trough; wherein the control means switches the operation to the cooking mode in response to the operation of the output fusing switch. The method of claim 1, wherein said step of placing butter into the fryer trough includes placing a solid shortening with the tundish of the fryer and said stage of observing the level of the shortening. It includes observing the level of the melt that has melted as a result of the melting operation mode of the heating system. SUMMARY The present invention provides a frying system including a fryer with a trough (12), with butter inside, a heat exchanger (14) placed inside the tundish (12), a heating mechanism to provide heat to the heat exchanger (14). ), and a control mechanism to control the heating mechanism. The control means repetitively changes the heating mechanism between an off condition and an ignition condition during a melt operation method and maintains the heating mechanism in an ignition condition during a cooking operation method. A manual switch is provided to change the control mechanism of the melt operation method to the cooking operation method. Also, a prevention mechanism is provided to prevent the control means from entering the cooking operation means, and consequently maintain the heating mechanism in an ignition condition, before the manual switch comes into action.