MULTI-ZONE FRYER AND METHOD OF MULTI-ZONE FRYING

Abstract

A multi-zone fryer (100) and method for preparation of fried food products (187) comprising an elongated cooking trough (105) for holding a volume of heated cooking oil (115), at least first and second rollers (106a, 106b), and a conveyor (110) arranged to extend and transport the food products in a direction from the first roller (106a) at an inlet end (120), along the bottom (121) of the trough to the second roller (106b) at an outlet end (122), wherein the elongated cooking trough (105) comprises at least a first and second cooking zone (140, 145), each cooking zone having oil level sensors (170,175,180,181) configured to co-operate and control an oil inlet control valve (184;184a) and an oil outlet control valve (185;185a) arranged in fluid connection with the trough (105) and an oil circulation system to ensure that a predetermined oil level is kept in the trough.

Claims

1. A multi-zone fryer for preparation of fried food products comprising an elongated cooking trough for holding a volume of heated cooking oil, at least first and second rollers, and a conveyor arranged to extend and transport the food products in a direction from the first roller at an inlet end, along the bottom of the trough to the second roller at an outlet end, wherein the elongated cooking trough comprises at least a first and second cooking zone, characterized in that each cooking zone has at least two oil level sensors, including a first oil level sensor and a second oil level sensor, wherein the first oil level sensor is arranged at the beginning of the cooking zone and the second oil level sensor is arranged at the end of the cooking zone, wherein a cooking process control device is configured to receive input signals from the oil level sensors and to control an oil inlet control valve and an oil outlet control valve of each cooking zone arranged in fluid connection with the trough and an oil circulation system to ensure that a predetermined oil level is kept in the trough.

2. The multi-zone fryer of claim 1, wherein the oil level sensors in different zones are configured to co-operate and, by means of the cooking process control device, control the oil inlet control valves and the oil outlet control valves of the different zones to ensure that a predetermined oil level is kept at the same level in the different zones in the trough.

3. The multi-zone fryer according to claim 1, comprising three, four, five or more cooking zones, arranged in fluid connection with each other along the length of the trough.

4. The multi-zone fryer according claim 1, wherein the oil level sensors in a particular zone are configured to co-operate and control the oil inlet control valve and the oil outlet control valve of said particular zone to ensure that a predetermined oil level is kept in the trough.

5. The multi-zone fryer according to claim 4, wherein the oil level sensors and the corresponding inlet and outlet valves are configured to co-operate in pairs, crosswise, or together to provide the predetermined oil level.

6. The multi-zone fryer according to claim 4, wherein the oil level sensors and the corresponding inlet and outlet valves are configured to provide the oil level in the trough at least at the height of the particular product on the conveyor belt, when the product is moved through every cooking zone along a horizontal main portion of the run to achieve a uniform deep-frying of the entire product.

7. The multi-zone fryer according to claim 1 wherein each cooking zone comprises an oil inlet an oil outlet having an intermediate part of the cooking trough extending between said oil inlet and oil outlet.

8. The multi-zone fryer of claim 7, wherein the cooking zones are in fluid connection, a first oil level sensor arranged at the beginning of the first cooking zone after and in proximity to a first oil inlet in said direction, a second oil level sensor arranged at the end of the first cooking zone before a first oil outlet, a third oil level sensor arranged at the beginning of the second cooking zone after and in proximity to ta second oil inlet, and a fourth oil level sensor arranged at the end of the second cooking zone and before a second oil outlet, each oil inlet is connected to an oil inlet circuit via an oil inlet control valve and each oil outlet is connected to an oil outlet circuit via an oil outlet control valve, wherein the first oil level sensor is configured to detect the oil level of the cooking oil in the trough near the first oil inlet and by means of the cooking process control device to control the first oil inlet control valve to regulate the flow of oil from the oil inlet circuit into the trough, the second oil level sensor is configured to detect the oil level near the first oil outlet and by means of the cooking process control device to control the first oil outlet control valve to control the flow of oil from the trough through to the first oil outlet to the oil outlet circuit, and the third oil level sensor is configured to detect the oil level of the cooking oil in the trough near the second oil inlet and by means of the cooking process control device to control the second oil inlet control valve to regulate the flow of oil from the oil inlet circuit into the trough, the fourth oil level sensor is configured to detect the oil level near the second oil outlet and by means of the cooking process control device to control the second oil outlet control valve to control the flow of oil from the trough through the second oil outlet to the oil outlet circuit until the predetermined cooking oil level is obtained in the through.

9. The multi-zone fryer of claim 7, wherein the oil inlet includes an inlet trough extending laterally along the width of the bottom of the cooking trough, wherein the sectional area of the inlet trough is rectangular, an angle plate facing a bottom corner forming a first chamber in the far end of the inlet trough, and a main chamber, wherein the top part of the angle plate has plurality of holes providing a fluid connection from the oil inlet circuit into the main chamber of the inlet trough, an inclined plate arranged in the main chamber extending from the bottom diagonally to a perforated outlet plate of the main chamber forming a first and second sub chamber, wherein the inclined plate extends along the width of the inlet trough with a gap along the bottom forming a fluid connection between the sub chambers, and the perforated outlet plate is provided with a pattern of lip shaped holes arranged to feed cooking oil into the trough in the same direction as the movement of the food products on the conveyor.

10. The multi-zone fryer according to claim 1, comprising a circulation pump configured to pump the cooking oil into the trough to provide a flowrate of the cooking oil individually in each zone to be equal or essentially equal to the speed of the conveyor belt in order to prevent turbulence.

11. The multi-zone fryer according to claim 1 wherein the cooking process control device is configured to control the operation of the multi-zone fryer.

12. The multi-zone fryer according to claim 11, wherein the process control device is operatively connected to and configured to receive input signals from the oil level sensors and to control the operation of the oil inlet and outlet valves and the oil circulation system including the oil inlet circuit and an oil outlet circuit, such that the predetermined oil level is kept in the trough.

13. A method for preparation of fried foodstuff in a multi-zone fryer according to claim 2, comprising: providing food products on the conveyor for transportation through the heated cooking oil to be fried, wherein the cooking oil level rises due to the displaced oil volume of the product; detecting the rise of the oil level by the first oil level sensor in the first cooking zone; controlling the first oil inlet control valve to regulate the flow of oil to be reduced from the oil inlet circuit into the trough through the first oil inlet in response to the detected cooking oil level; detecting the rise of the oil level by the second oil level sensor; controlling the first outlet control valve to regulate the flow of oil from the trough through the first outlet; detecting the oil level by the third oil level sensor in the second cooking zone; controlling the another oil inlet control valve to regulate the flow of oil from the oil inlet circuit into the trough through the second oil inlet in response to the detected oil level; detecting the oil level by the fourth oil level sensor; controlling the another outlet control valve for regulating the flow of oil from the trough through the second outlet to ensure that a predetermined oil level is kept in the trough.

14. The method of claim 13, wherein the predetermined oil level in the trough is regulated to be at a level between 5-100 mm.

15. The method of claim 13, wherein the predetermined oil level in the trough is regulated to be at a level between 10-35 mm.

16. A computer program comprising program instructions for causing a cooking process control device having computer capability to perform a method for preparation of fried foodstuff in a multi-zone fryer according to claim 2, when said program is run on said cooking process control device, the method comprising: detecting the rise of the oil level by receiving an input signal from the first oil level sensor in the first cooking zone; controlling the first oil inlet control valve to regulate the flow of oil to be reduced from the oil inlet circuit into the trough through the first oil inlet in response to the detected cooking oil level; detecting the rise of the oil level by receiving an input signal from the second oil level sensor; controlling the first outlet control valve to regulate the flow of oil from the trough through the first outlet; detecting the oil level by receiving an input signal from the third oil level sensor in the second cooking zone; controlling the another oil inlet control valve to regulate the flow of oil from the oil inlet circuit into the trough through the second oil inlet in response to the detected oil level; detecting the oil level by receiving an input signal from the fourth oil level sensor; controlling the another outlet control valve for regulating the flow of oil from the trough through the second outlet to ensure that a predetermined oil level is kept in the trough.

17. A computer program according to claim 16 on a carrier.

18. The computer program according to claim 17, wherein said carrier is a record medium, computer memory, read-only memory, computer-readable medium or an electrical carrier signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Exemplary embodiments is illustrated by way of example in the accompanying drawings in which like reference numbers indicate the same or similar elements and in which:

[0043] FIG. 1 is a cross-sectional view of a multi-zone fryer according to a first embodiment;

[0044] FIG. 1A is a perspective view of a portion of the multi-zone fryer shown in FIG. 1 including synchronized dual drive of a conveyor belt;

[0045] FIG. 2 is a perspective view of a portion of the multi-zone fryer shown in FIG. 1;

[0046] FIG. 3 is a close-up perspective view of a portion of the multi-zone fryer shown in FIG. 2;

[0047] FIG. 4 is a close-up cross-sectional view of a portion of the multi-zone fryer shown in FIG. 1;

[0048] FIG. 5 is a close-up cross-sectional view of a portion of the multi-zone fryer shown in FIG. 4;

[0049] FIG. 6A is a close-up cross-sectional view of a portion of the multi-zone fryer shown in FIG. 1;

[0050] FIG. 6B is a close-up perspective view of a portion of the multi-zone fryer shown in FIG. 1;

[0051] FIG. 7 is a schematic block diagram of a control system for running the operation of the multi-zone fryer in FIG. 1; and

[0052] FIG. 8 is a flowchart of a method for frying food products using a multi-zone fryer as shown on FIG. 1

DESCRIPTION OF EMBODIMENTS

[0053] Embodiments of the invention will be described with reference to FIGS. 1-8. In cooperation with attached drawings, the technical contents and detailed description of the present invention are described hereinafter according to embodiments, not used to limit the scope. Any equivalent variation and modification made according to appended claims are covered by the claims.

[0054] Reference will now be made to the figures to describe the embodiments in detail. The same reference signs are used for corresponding features in different figures.

[0055] Reference is made to FIG. 1, which is a multi-zone fryer 100 or deep-fryer for preparation of fried or deep-fried food products such as, but not limited to, potato cakes or croquettes in accordance with a first embodiment. The multi-zone fryer 100 comprises a frame 102 supporting an elongated cooking trough or vessel 105, at least first and second rollers 106a, 106b, and a conveyor, for example a conveyor belt 110. The trough 105 may hold a volume of heated cooking oil 115 up to a desired level. The conveyor belt 110 is arranged to extend from the first roller 106a, which is arranged at an inlet end 120 of the multi-zone fryer 100, along the bottom 121 of the trough to the second roller 106b, which is arranged at an outlet end 122 of the multi-zone fryer 100. The conveyor belt 110 and the rollers 106a, 106b forming a run comprising a first inclined portion 125 from the first roller 106a at the inlet end 120 down to the bottom 121, a horizontal main portion 130, and a second inclined portion 135 from the bottom 121 up to the second roller 106b at the outlet end 122. The rollers 106a, 106b and the conveyor belt 110 may be driven by at least one electric drive motor or any other drive.

[0056] The elongated cooking trough 105 of the multi-zone fryer 100 may further comprise a plurality of cooking zones. In the embodiment, the cooking trough 105 comprises, but is not limited to, two cooking zones, i.e a first cooking zone 140 and a second cooking zone 145. Each cooking zone may comprise an oil inlet, an oil outlet, and the intermediate part of the cooking trough 105 extending between said oil inlet and oil outlet. In this embodiment of the multi-zone fryer 100, the first cooking zone 140 comprises a first oil inlet 150 and a first oil outlet 155, and the second cooking zone 145 comprises a second oil inlet 160 and a second oil outlet 165.

[0057] In some embodiments, the multi-zone fryer may comprise 3, 4, 5 or more zones, each zone including an oil inlet, an oil outlet, and an intermediate part of the cooking trough. Although, the trough is divided in two or more cooking zones, the cooking zones are all in fluid connection with each other. Therefore, cooking oil may flow from one cooking zone to another along the length of the trough 105. The multi-zone fryer 100 with oil inlets and oil outlets are arranged to provide a flow of the cooking oil preferably in the same direction as the direction of the conveyor belt 110, i.e in the direction from the first cooking zone 140 to the second cooking zone 145.

[0058] Each zone comprises at least two oil level sensors. In this embodiment of the multi-zone fryer, a first oil level sensor 170 is arranged at the beginning of the first cooking zone 140 after and in proximity to the first oil inlet 150 in the direction of the oil flow from the inlet 120 to the outlet 122. A second oil level sensor 175 is arranged at the end of the first cooking zone 140 before the first oil outlet 155 in the direction of the oil flow. Similarly, a third oil level sensor 180 is arranged at the beginning of the second cooking zone 145 after and in proximity to the second oil inlet 160 in the direction of the oil flow. A fourth oil level sensor 181 is arranged at the end of the second cooking zone 145 and before the second oil outlet 165 in the direction of the oil flow.

[0059] Reference is made to FIG. 2, which is a perspective view of a portion of the multi-zone fryer 100 in FIG. 1. The oil inlets 150, 160 are configured to provide heated cooking oil to the cooking trough 105 from a cooking oil circulation system. The cooking oil circulation system comprises an oil inlet circuit 182 with pipes and an oil outlet circuit 183 with pipes connected to a heat exchanger 210 (illustrated in FIG. 7) for heating the cooking oil, i.e vegetable oil, outside the cooking trough 105. Heated cooking oil is fed to the cooking trough 105 by a circulation pump 107 (illustrated in FIG. 7) of the oil circulation system via the oil inlet circuit 182 through the first oil inlet 150 of the first cooking zone 140 and the second oil inlet 160 of the first cooking zone 145. Oil is removed from the trough 105 through the first oil outlet 155 in the first zone 140 and the second oil outlet in the second zone 145. As illustrated in FIG. 2, the oil outlet 150 and oil inlet 160 extend laterally along the width of the bottom of the cooking trough 105.

[0060] Each oil inlet is connected to the oil inlet circuit via an oil inlet control valve and each oil outlet is connected to the oil outlet circuit via an oil outlet control valve. The first oil inlet 155 in the first zone is connected to the oil inlet circuit 182 via a first oil inlet control valve 184, and the first oil outlet 155 is connected to the oil outlet circuit 183 via a first oil outlet control valve 185.

[0061] As illustrated tin FIG. 2, the first oil level sensor 170 is configured to detect the oil level of the cooking oil in the trough 105 near the first oil inlet 150 and to control the first oil inlet control valve 184 to regulate the flow of oil from the oil inlet circuit 182 into the trough 105 through the first oil inlet 150. The second oil level sensor 175 is configured to detect the oil near the first oil outlet 155 and to control the first oil outlet control valve 185 to control the flow of oil from the trough 105 through the first oil outlet 155 to the oil outlet circuit 183.

[0062] Therefore, the multi-zone fryer 100 is configured to provide the oil level in the trough at least at the height of the particular food product on the conveyor belt, when the product is moved through every cooking zone 140, 145 along the horizontal main portion 130 of the run. Thereby, the heated cooking oil 115 covers the food product during the cooking to achieve a uniform deep-frying of the entire product.

[0063] Since the conveyor belt and food products, e.g shaped potato products to be fried singularly, move the oil through the reservoir at different speeds depending on the frying time, the level profile will change.

[0064] When preparation starts and food products 187 enter the conveyor belt 110 as illustrated in FIG. 3, the oil level rises due to the displaced oil volume of the product. The rise of the oil level is detected by the first oil level sensor 170, which controls the first oil inlet control valve 184 to regulate the flow of oil to be reduced from the oil inlet circuit 182 into the trough 105 through the first oil inlet 150. Depending on the how much the oil level tends to rise, even the second oil level sensor 175 may detect a rise of the oil level. In that case the second oil level sensor 175 controls the first outlet control valve 185 to regulate the flow of oil from the trough 105 through the first outlet 155.

[0065] On the other hand, if the cooking oil level is detected to decrease by one or more of the oil level sensors in a cooking zone, the inlet control valve in that zone is regulated to open to some degree in order to increase the flow of oil through the oil inlet into the through until the predetermined cooking oil level is obtained in the through.

[0066] Hence, the oil level sensors in a particular zone may be configured to co-operate and control the oil inlet control valve and the oil outlet control valve of said particular zone to ensure that a predetermined oil level is kept in the trough. Since the predetermined oil level is desirable or rather required in each cooking zone along the length of the trough, the oil level sensors and the corresponding inlet and outlet valves may be configured to co-operate in pairs, crosswise, or together to provide the predetermined oil level. If the cooking level rises in a cooking zone the outlet control valve at the end of that zone is controlled to open to some degree until the predetermined cooking oil level is obtained in the through. If the cooking oil level is reduced, due to an increased speed of the conveyor belt causing a pump effect, the outlet control valve at the end of that zone may be regulated to close to some degree until the predetermined cooking oil level is obtained in the through. Preferably, the flow rate of the cooking oil should be at a similar speed as the speed of the conveyor belt.

[0067] FIG. 4 is a cross-sectional view of a portion of the multi-zone fryer 100 illustrating the first cooking zone 140 in further detail.

[0068] FIG. 5 is a close-up cross-sectional view of a portion of the multi-zone fryer illustrating the first oil inlet 150 including an inlet trough 190 extending laterally along the width of the bottom 121 of the cooking trough 105. The sectional area of the inlet trough may be rectangular. An angle plate 192 facing a bottom corner 193 forms a small first chamber 195 in the far end of the inlet trough 190 facing away from the inlet end 121, and a main chamber 196. The top part of the angle plate 192 has plurality of holes 197 providing a fluid connection from the oil inlet circuit 182 into the main chamber 196 of the inlet trough 190. An inclined plate 198 is arranged in the main chamber 196 extending from the bottom 199 diagonally to a perforated outlet plate 200 of the main chamber 196 forming a first sub camber 196a and second sub chamber 196b. The inclined plate 198 extends along the width of the inlet trough 190 with a narrow gap 201 along the bottom 199 forming a fluid connection between the sub chambers 196a and 196b. The perforated outlet plate 200 is provided with a pattern of lip shaped holes arranged to feed cooking oil into the through in the same direction as the movement of the food products on the conveyor belt. However, the cooking oil should be pumped into the through relatively slow in order to prevent turbulence.

[0069] Thus, the oil inlet circuit 182 is arranged in fluid connection with the cooking trough 105 via a labyrinth including the inlet trough 190, the holes 197 to the first sub chamber 196a, the inclined plate 198, the narrow gap 201, the second sub chamber 196b, and the perforated outlet plate 200. During preparation the cooking oil flows through the labyrinth in a direction illustrated by the arrows in FIG. 5.

[0070] FIGS. 6A and 6B show close-up cross-sectional views of portions of the multi-zone fryer shown in FIGS. 1 and 1A. As described above, the rollers 106a, 106b and the conveyor belt 110 may be driven by the at least one electric drive motor. In this embodiment of the multi-zone fryer, the underside of the conveyor belt 110 is provided with one or more transvers scrapers 205 arranged to sweep or scrape sediment and deposit from the bottom 121 of the trough when the conveyor belt 110 is moving along the length of the through 105. Thereby, the sediment and deposit follow the flow of cooking oil towards the oil outlets 155, 165 for filtration by filtering means of the cooking oil circulation system. The rollers 106a, 106b are open and provided with flat bars 206 or strips extending from the circumference of and transvers along the width of the rollers. The scrapers 205 may fit into gaps 207 between the flat bars forming teeth to drive the conveyor belt. Since the scrapers 205 and teeth 206 extend along the width of the rollers, potential wear is reduced. Due to the gaps or openings 207 between the scrapers 205 of the open rollers 106a, 106b, sediment and deposit are allowed to pass through the rollers, thereby preventing accumulation of sediment and deposit.

[0071] Referring to FIG. 7, a block diagram of a control system is illustrated, which may comprise a cooking process control device 700, configured to run the operation of the multi-zone fryer 100. The cooking process control device 700 may be located within a cabinet of the multi-zone fryer and is operatively connected to and configured to receive input signals from the oil level sensors 170, 175, 180, 181 and to control the operation of the oil inlet and outlet valves 184, 185, 184a, 185a according to the method described below. Further, the cooking process control device 700 may be operatively connected to and configured to control the operation of the oil circulation system including the oil inlet circuit 182 and an oil outlet circuit 183, and the heat exchanger 210. As describe above, heated cooking oil is provided to the cooking trough 105 by the circulation pump 107, which may also be controlled by the cooking process control device. The at least on drive motor for driving the rollers 106a, 106b may also be operatively connected to and controlled by the cooking process control device 700.

[0072] FIG. 1A is schematic perspective view of a synchronized dual drive of the conveyor belt 110. In this embodiment, the dual drive comprises a first separate drive 136a operatively connected to the first roller 106a and a second separate drive 136b operatively connected to the second roller 106b. The first and second separate drives 136a and 136b may be electric drive motors or any other drives. In this embodiment, a slave computer device 700a is connected to and configured to control the operation of the first separate drive 136a, and a master computer device 700b is connected to and configured to control the operation of the second separate drive 136b and to achieve synchronized dual drive of the conveyor belt 110. Thereby, the conveyor belt advantageously will follow the bottom 121 of the cooking trough 105 on the sliding strips 202 along the length of the trough up to about at least, but not limited to, 20 to 30 m. In one embodiment, the trough 105 and conveyor may be about 25 m. The master computer device 700b and the slave computer device 700a may be operatively connected to the cooking process control device 700. In one embodiment, the cooking process control device 700 may be configured to control the overall operation to achieve synchronized dual drive of the conveyor belt 110 via the master computer device 700b and the slave computer device 700a.

[0073] In one embodiment, the cooking process control device 700 is configured to control the circulation pump/s 107 to provide a flowrate of the cooking oil individually in each zone to be equal or essentially equal to the speed of the conveyor belt, for example but not limited to 0.15-0.5 m/s. Advantageously, the synchronization of the flowrate of the cooking oil with the movement of the conveyor belt will cause the products to stay on the conveyor belt during the frying process along the cooking trough.

[0074] Reference is made to FIG. 8, which is a flowchart of a method for preparation of fried foodstuff according to an embodiment. The method may involve a multi-zone fryer according to the present disclosure.

[0075] Initially, the cooking trough 105 is filled with heated cooking oil 110 via the oil inlets 150, 160 to a desired level, which may be, but is not limited to, 5-100 mm or preferably 10-35 mm depending on the thickness of the products 187. The cooking oil is circulated by means of the oil circulation system. The cooking oil may be withdrawn from the trough 105 through the oil outlets 155, 165 by means of the pump 107 before it is reheated to a determined temperature, which may be 150-195° C., preferably 170-180° C., by the heat exchanger and forwarded via the oil inlet circuit 182 through the oil inlets 150, 160.

[0076] The cooking process or preparation starts by providing 300 food products 187 on the conveyor belt 110 for transportation through the heated cooking oil to be fried in the multi zone fryer 100. The cooking oil level rises due to the displaced oil volume of the product. The rise of the oil level is detected 305a by the first oil level sensor 170, which controls 310a the first oil inlet control valve 184 to regulate the flow of oil to be reduced from the oil inlet circuit 182 into the trough 105 through the first oil inlet 150 in response to the detected cooking oil level. Depending on how much the cooking oil level tends to rise, even the second oil level sensor 175 may detect 305b a rise of the oil level. In that case the second oil level sensor 175 controls 310b the first outlet control valve 185 to regulate the flow of oil from the trough 105 through the first outlet 155. The temperature of the cooking oil may drop about 5-15° C. from the inlet to the outlet in each zone of the trough.

[0077] The cooking oil level may vary even in the second zone 145. The oil level is detected 305c by the third oil level sensor 180, which controls 310c another oil inlet control valve 184a to regulate the flow of oil from the oil inlet circuit 182 into the trough 105 through the second oil inlet 160 in response to the detected oil level. Depending on the how much the cooking oil level tends to rise, even the fourth oil level sensor 181 may detect 305d a rise of the oil level. In that case the fourth oil level sensor 181 controls 310d the another outlet control valve 185a to regulate the flow of oil from the trough 105 through the second outlet 165. At the end of the process, fried food products are removed 400 from the cooking trough.

[0078] Hence, the oil level sensors in a particular zone may be configured to co-operate and control the oil inlet control valve and the oil outlet control valve of said particular zone to ensure that a predetermined oil level, which may be, but is not limited to, 5-100 mm or preferably 10-35 mm depending on the thickness of the products 187, is kept in the trough. More particularly, the cooking process control device 700 is configured to control the oil inlet control valves and oil outlet control valves of each zone in response to sensor signals of the oil level sensors. Since the same predetermined oil level is desirable or rather required in each cooking zone along the length of the trough, the oil level sensors and the corresponding inlet and outlet valves may be configured to co-operate in pairs, crosswise, or together to provide the predetermined oil level. In some embodiments, the cooking process device may be configured to control the different valves within a particular control interval. For example, the outlet valves may not be closed and the inlet valves may have a limited maximum opening. Moreover, the control system and the cooking process device may be configured with self-learning capability, i.e the cooking process device is configured to operate according to a self-learning algorithm that ingests new data as it becomes available from the different sensors. The cooking process control device 700 is trained and continuously adapted in response to the new data. For example, if the control system detects only small variations of the oil level in the trough, the control level interval is reduced over time, thereby making the control system more stable or inert. However, the control system is configured to use control intervals of a relatively large range according to a selected recipe at the beginning of a cooking process. Thereby, the control system is adapted to be responsive to a big change in the oil level in the trough when the food products enter into the oil of the trough. During the cooking process, the control system may be trained.

[0079] In some embodiments, the oil level sensors in different zones may be configured to co-operate and control the oil inlet control valves and the oil outlet control valves of the different zones to ensure that a predetermined oil level, which may be, but is not limited to, 5-100 mm or preferably 10-35 mm, depending on the thickness of the products 187, is kept at the same level in the different zones in the trough.

[0080] Embodiments of the present invention have been described herein with reference to a multi-zone fryer and the operation of the multi-zone fryer. It will be understood that the control of the operation of the multi-zone fryer and the method of preparation of fried foodstuff may be implemented in the form of an entirely hardware embodiment, including but not limited to the cooking process control device 700, or an embodiment combining software and hardware aspects including computer program instructions to control the different components and systems of the multi-zone fryer. These computer program instructions may be provided to a processor of the cooking process control device, a general purpose computer, special purpose computer, computing device or any other programmable data processing apparatus of the multi-zone fryer, such that the instructions when executed create means for implementing the specified functions/acts of the multi-zone frying process to operate the multi-zone fryer accordingly. The multi-zone fryer is operated according to different recipes, which are defined by means of different computer program products operating on different parameters, including temperatures, frying time, cooking oil level etc.

[0081] The master computer device 700b and the slave computer device 700a may be implemented in the form of an entirely hardware embodiment, or an embodiment combining software and hardware aspects including computer program instructions, to control the operation of the first and second drives 136a, 136b to provide synchronized dual drive of the conveyor belt 110.

[0082] The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention, which fall within the scope of the technology. However, although embodiments of the method and apparatus of the technology has been illustrated in the accompanying drawings and described in the foregoing detailed description, the disclosure is illustrative only and changes, modifications and substitutions may be made without departing from the scope of the technology as set forth and defined by the following claims.