Food processing systems using oil

Abstract

The present invention provides a method for treating food with oil, comprising: a container for oil; a conveying device for conveying food through the oil in the container, including an endless conveyor belt; a supply device for supplying oil; a discharge device for discharging the oil; a heating device for heating the oil; the supply device comprises: at least one supply body, including: an elongated collecting space for oil, and at least two supply conduits, wherein each supply conduit is adjacent to the collecting space and ends at the bottom of the container through an outlet opening of the corresponding supply conduit, a pump for supplying oil heated by the heating device to the collecting space, and a metering device for metering the amount of oil supplied to the outlet opening, wherein the metering device has an adjustable channel opening on each supply conduit, through which the oil can flow from the collecting space into the supply conduit.

Description

Technical Field

[0001] The invention relates to a system for treating food with oil, comprising a container with a bottom for containing oil and a conveying device for conveying food to be treated by the oil in the container along a conveying direction. Background Art

[0002] The conveying device comprises an endless conveyor belt wrapped around a deflector roller, which is arranged at both ends of the system so that the food is located on the carrying stroke of the conveyor belt. When using this processing system, the food in the oil stays on the conveyor belt, and the food is transported through the oil along the conveying direction by the conveyor belt. This processing system is described in the international patent application WO 01 / 28395A1. This processing system is intended for foods that tend to sink into the oil. French fries or relatively thick potato chips are examples of such foods. In general, it involves foods with a specific gravity greater than the specific gravity of the oil. The typical value of the specific gravity of the oil is 0.82 kilograms per liter at least at the temperature often used in practice according to the system of the present invention. In particular, when treating food with an oil with a specific gravity lower than that of the oil, it is known that continuous ovens do not use conveyors. In this device, the food floats in the oil and is driven along the flow direction of the oil by creating a flow in the oil in the same direction of conveyance. In this case, the specific gravity of the food product may be reduced during the contact treatment with the oil because moisture may escape from the food product. For example, for foods such as potato chips, air-filled voids may be created. The flow in the oil is created by supplying the oil on the food delivery side of the container and draining the oil on the opposite side of the container, while the treated food is removed from the oil. In this case, it is also known to use co-rotating immersion belts, paddles, flaps or screws to adjust the residence time of the food in the oil. US 5,085,137, EP 2670261 A1 and US 2017 / 0127882 A1 describe such continuous frying ovens without a conveyor belt. Summary of the invention

[0003] The present invention aims to provide a system according to the preamble, by which foodstuffs having a specific gravity greater than that of the oil used can be similarly treated by means of oil, while these foodstuffs located on a conveyor belt are conveyed by means of the oil. In this case, the invention is based on the understanding that the generation of vortices in the oil pool has a negative impact on the degree of similar treatment of the foodstuffs. The reason is that vortices may cause individual foodstuffs to temporarily detach from the conveyor belt and rotate in the oil pool, so that the residence time of the foodstuffs in the pool may vary. The invention is also based on the understanding that there is a relationship between the way in which the oil is supplied to the container and the risk of the occurrence of vortices. More specifically, the invention is based on the understanding that the way in which the oil is supplied to the container through a slit-shaped supply channel is not optimal for preventing vortices.

[0004] The invention provides a system as claimed in claim 1. By providing the system with a metering device which provides an adjustable channel opening for each supply duct through which the oil is supplied to the container, a stable supply of oil to each supply duct can be achieved, which not only improves a uniform heat input to the oil over the entire pool width, but also reduces the risk of vortices. This therefore facilitates the same treatment of the food by the oil in the pool. It has been found that, in particular, by providing the supply body with two or more supply ducts, the occurrence of vortices can be prevented.

[0005] In a further embodiment, in which the supply body comprises three or more supply ducts, the outlet openings are arranged in a row, transversely to the conveying direction. The mutual distance of the outlet openings is preferably between 5 cm and 30 cm.

[0006] In a specific embodiment with structural simplicity, the metering device includes at least one metering body having a metering channel for each supply duct, wherein a transparent portion of the metering channel forms a channel opening, and at least one metering body can be moved relative to at least one supply duct in a metering position to adjust the size of at least one channel opening according to the metering position used.

[0007] In embodiments where the supply body comprises two or more supply ducts, a steady supply of oil to the sump is improved if the dimensions of the individual channel openings are identical to one another, regardless of the metering position used.

[0008] In a practical embodiment, the metering body is rotatable relative to the at least one supply duct about an axis of rotation, in which case the axis of rotation can extend parallel to the row.

[0009] In a further embodiment, the metering body has an at least partially circular, preferably completely circular cross section. Such a metering body may be adapted to rotate.

[0010] Furthermore, it may be preferred if the at least one metering channel extends between two radially opposite sides of the at least partially circular cross section.

[0011] In a further embodiment, the metering body is slidable relative to the at least one supply duct. By sliding the metering body, various metering positions can be set.

[0012] In an embodiment in which the supply body comprises three or more supply ducts and the associated outlet openings are arranged in a row, it is further preferred that the metering body is slidable relative to at least one of the supply ducts parallel to the row.

[0013] If the metering body is strip-shaped, a structurally simple embodiment can be achieved, wherein at least one metering channel can be easily created by means of a hole.

[0014] According to a further embodiment, for structural simplicity and uniform heat input, it may further help if the container has a width and the length of the collecting space is at least equal to 85% of the container width dimension. Thus, the at least one outlet opening can cover the entire width of the container or at least nearly the entire width in a simple manner.

[0015] Alternatively, the system can also comprise two mutually aligned supply bodies. This can be particularly advantageous for relatively wide containers, for example containers with a width of more than 1.5 meters, for example containers with a width of 3 meters. In this case, it is important that the channel openings associated with the respective two mutually aligned supply bodies are driven in a similar manner, in the sense that the dimensions of the channel openings are identical to each other and remain identical.

[0016] Especially for relatively wide containers, it may also be advantageous if the system consists of two metering bodies aligned with each other. Also in this case, it is important to drive the respective metering bodies in a similar manner.

[0017] In a further embodiment, the system comprises a servomotor for driving the displacement of the metering body between metering positions. Using the servomotor, the size of at least one passage opening can be adjusted depending on the measurement of the sensor, thereby regulating the oil flow into the container. The sensor forms part of a control circuit, as does the servomotor. The respective measurement may relate, for example, to the amount of oil in the container, the temperature of the oil in the container and / or the quality of the oil in the container.

[0018] The temperature of the oil, viewed in the conveying direction, can be controlled more accurately if the system comprises at least two supply bodies, which are spaced apart in the conveying direction. Advantageously, in this case, each supply body comprises an elongated collecting space, the longitudinal extension of which is transverse to the conveying direction, and at least two supply ducts as described above. Alternatively, at least one supply body can also have such an elongated collecting space and at least two supply ducts, and at least one supply body can have a conventional design.

[0019] The above advantages may be particularly relevant if the outlet opening associated with at least one (preferably each) of the at least two supply bodies is arranged at a certain distance from the opposite ends of the bottom, for example in a region between 25% and 75% of the distance between the above ends, viewed in the conveying direction.

[0020] The risk of vortices occurring in the oil can also be reduced if the discharge device comprises at least one discharge opening in the bottom of the container and at least one discharge line connected to the at least one discharge opening.

[0021] In order to further control the temperature of the oil, it is advantageous if the discharge device comprises at least two discharge openings in the bottom of the container, and the at least two discharge openings are spaced apart in the conveying direction. In particular, the temperature of the oil can be better controlled if the at least two discharge openings at a distance from the bottom of the container are also spaced apart from opposite ends of the bottom.

[0022] In a further embodiment of the system, a drain is provided upstream of the at least one outlet opening, viewed in the conveying direction, in order to prevent oil just supplied to the container from being immediately discharged by the drain. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is explained in more detail with the aid of a description of a possible embodiment of the system according to the invention, with reference to the following figure, in which:

[0024] Figure 1a A schematic side view of a system for treating food with oil according to the present invention;

[0025] Figure 1b Shows Figure 1a A top view of the system in FIG.

[0026] Figure 2a A side view showing a portion of a supply device in a system according to the invention;

[0027] Figure 2b Shows Figure 2a A top view of the supply device in FIG.

[0028] Figure 3a shows a partially cut-away elevational view of an embodiment of a metering device that can be used in the system according to the previous figure;

[0029] Figure 3b Shows Figure 3a Cross section IIIb-IIIb in;

[0030] Figure 4a a partially cut-away front view showing an alternative embodiment of a metering device;

[0031] Figure 4b Shows Figure 4a Cross section IVb-IVb in FIG. DETAILED DESCRIPTION

[0032] Figure 1a and Figure 1b A system 100 is shown for treating food products, such as potato chips or French fries, with oil 103, which has a higher specific gravity than the oil 103. Therefore, the corresponding food products tend to sink in the oil 103.

[0033] The system 100 comprises a container 101 configured as a deep fryer, having a bottom 121 for oil 103 and a conveying device having an endless conveyor belt 102, which is wound, among other things, around guide rollers 119a, 119b arranged at opposite ends of the system 100. The carrying path of the conveyor belt 102 slopes downwards in an upstream portion 102a, extends horizontally in a central portion 102b and slopes upwards in a downstream portion 102c. The central portion 102b is completely covered with oil 103. The respective top ends of the upstream portion 102a and the downstream portion 102c are located above the oil level 103. By means of the conveying device, the food to be treated with oil 103 can be conveyed from the deep fryer 101 through the oil 103 in a conveying direction T by appropriately driving in rotation at least one guide roller 119a, 119b, wherein the individual products are located on the carrying path of the conveyor belt 102.

[0034] The system 100 further comprises a circulation system for the oil 103. The circulation system comprises a piping system for the oil 103, which is connected to the deep frying pan 101 and comprises a circulation pump 109. The portion of the circulation system located on the upstream side of the circulation pump 109 forms together with the circulation pump 109 a discharge device for discharging the oil 103 from the deep frying pan 101. The portion of the circulation system located on the upstream side of the circulation pump 109 forms together with the circulation pump 109 a supply device for supplying the frying pan 103 with oil.

[0035] The discharge device comprises discharge lines 107a, 107b and 107c, through which the oil 103 is discharged from the deep frying pan 101 in the direction of the pump 109 through the respective discharge openings 106a, 106b and 106c in the bottom 121. The discharge device also comprises a filtering system (not shown), which is known per se to a person skilled in the art and is used to filter the oil 103 from the deep frying pan 101. In the present embodiment, the discharge openings 106a, 106b, 106c are located at positions approximately 1 / 3, 2 / 3 and near the downstream end of the length of the deep frying pan 101, respectively. The respective downstream ends of the discharge lines 107a and 107b are connected to the discharge line 107c. In general, regardless of the number of the discharge openings, at least they are arranged at almost equal distances.

[0036] The supply device comprises a supply line 131 extending between the pump 109 and the manifold 117. A continuous flow heating device 108 is incorporated into the supply line 131 for heating the oil 103 flowing through the supply line 131. The supply device also comprises supply lines 105a, 105b and 105c extending between the manifold 117 and the metering devices 112a, 112b and 112c, respectively. As shown in FIG. 2B , there are four supply lines 105b and four supply lines 105c. The metering device 112a is of a different type from the metering devices 112b and 112c. The metering devices 112b and 112c are particularly important for the present invention and two possible embodiments of such metering devices will be described in more detail below with the aid of FIGS. 3 and 4 . As for the metering device 112a, it should be noted that a control valve 133 has been installed at the downstream end of the supply line 105a towards the metering device 112a, which valve is well known to those skilled in the art. As with the case of the discharge ports, the metering devices are generally placed at least nearly at equal distances. In addition, the number of metering devices may also be different from the number of discharge ports, for example, may be greater than the latter.

[0037] The metering device 112a includes a distribution pipe 141 (see Figure 2a and 2b ), which spans the entire width of the deep frying pan 101 and from which, in the present embodiment, six supply lines 142 extend. Alternatively, the number of supply lines can also be greater or less, for example two or more, ten or less. The mutual distance is preferably between 20 cm and 40 cm, for example 30 cm. The supply lines 142 end in a pressure space 144, which is provided with an upwardly directed slit-shaped outlet opening 143 at the top, and by means of this outlet opening 143, more specifically, ends at the bottom 121 of the deep frying pan 101 on its upstream side, so that the food immediately after the oil 103 supplied to the deep frying pan 101 experiences the effect of the oil 103 provided to the deep frying pan 101 through the outlet opening 143. The amount of oil 103 supplied to the deep frying pan 101 through the outlet opening 143 is controlled by adjusting the control valve 133.

[0038] Figure 3a The metering device 112b is shown in more detail. The design of the metering device 112c is similar to that of the metering device 112b. The metering device 112b has an elongated collecting space 151 which extends in the horizontal direction at right angles to the conveying direction T and whose length is almost equal to the width of the deep frying pan 101. Four supply lines 105b end in the collecting space 151 at equal distances, so that the oil 103 can be evenly distributed along the length of the collecting space 151 via the supply lines 105b.

[0039] Directly above the collecting space 151, the metering device 112b further comprises an elongated outlet body 152, which is rigidly connected to the collecting space 151 and in which the discharge ducts 111 are arranged parallel to each other and equidistant from each other. The top end of the discharge duct 111 ends at an outlet opening 153 of the deep frying pan 101, which coincides with the bottom 121 of the deep frying pan 101. The outlet openings 153 are evenly distributed and form a row which is transverse to the conveying direction T and spans almost the entire width of the deep frying pan 101. The outlet openings 153 are also arranged at a short distance downstream from the discharge opening 106a or 106b.

[0040] An at least substantially cylindrical space is provided between the collecting space 151 and the outlet body 152, which space extends along the entire length of the collecting space 151. In this space, a cylindrical metering body 115 with an axis 154 is provided. Metering ducts 118 are provided in the metering body 115 at the same spacing as the discharge duct 111, and these metering ducts 118 pass through the metering body 115 transversely to the central axis 154 of the metering body 115. The cross-sectional shape and diameter of the metering duct 118 are the same as those of the discharge duct 111. The top end of the metering duct 118 forms a passage opening for the oil 103, for the portion where the top end of the metering duct 118 overlaps with the bottom end of the associated discharge duct.

[0041] The metering body 115 is rotatable about a central axis 154 and can be driven for this purpose via a servomotor 155 through a gear transmission 120 or, alternatively, manually in an embodiment without a servomotor 155 and without a transmission 120. The gear transmission 120 comprises a gear 161 on an output shaft 162 of the servomotor 155. The use of a servomotor provides the possibility of automatically controlling the speed at which the oil 103 is supplied to the deep frying pan 101, which depends on the required oil 103 supplied to the deep frying pan 101, for example based on a measurement of the quality and / or temperature of the oil in the deep frying pan 101.

[0042] Gear 161 meshes with gear 163 and both are arranged to rotate together with gear 164 on shaft 165. Gear 164 meshes with gear 166 which is rigidly connected to shaft 167. Shaft 167 is rigidly connected to metering body 115. Appropriate excitation of servomotor 155 can rotate the metering body through a desired angle.

[0043] Figure 3bThe cross-sectional view shows how the rotation of the metering body 115 causes the top end of the metering conduit 118 to abut against the bottom end of the discharge conduit 111, so that in the fully flowing position, the metering conduit 118 abuts against the discharge conduit 111. In this case, the size of the passage opening is equal to the cross-sectional size of the metering conduit 118. In the fully closed position, the metering conduit 118 is not at all adjacent to the discharge conduit 111, so that no oil 103 from the collecting space 151 can reach the discharge conduit 111. Therefore, the size of the passage opening is equal to zero. By appropriately exciting the servomotor 155, the metering body 115 is positioned in a metering position between this fully flowing position and the fully closed position, and the amount of oil 103 that can reach the discharge conduit 111 from the collecting space 151 can be metered. According to the continuously variable metering position, the size of the passage opening is therefore between zero and the size of the cross section of the metering conduit 118.

[0044] Figure 4a and 4b An alternative metering device 212 is shown which is similar to metering device 112b. The differences from metering device 112b will be discussed in more detail below.

[0045] The metering device 212 includes an elongated collecting space 251, and its supply line is such as the supply line 105b (not shown). Figure 4a and 4b 103 is connected to the supply line to supply the oil 103 to the collecting space 251. Directly above the collecting space 251, the metering device 212 further comprises an elongated outlet body 252 rigidly connected to the collecting space 251 and in which the discharge conduits 211 parallel to each other are arranged. The top end of the discharge conduit 211 is at the outlet opening 253, which coincides with the bottom 121 of the deep frying pan 101.

[0046] Between the collecting space 251 and the outlet body 252, a rectangular space is provided which extends along the entire length of the collecting space 251 and contains a strip-shaped metering body 215. A metering conduit 218 is provided in the metering body 215 at a similar mutual distance to the discharge conduit 211. The cross-sectional shape and diameter of the metering conduit 218 are the same as those of the discharge conduit 211.

[0047] The metering body 215 can be slid in a reciprocating manner by means of a servo motor (not shown) along the double arrow 261. Alternatively, this can also be achieved by an actuator motor or a pneumatic or mechanical adjustment device, which can be manually operated or not. Figure 4bThe cross-sectional view of shows how the top end of the metering conduit 218 is brought into abutment with the bottom end of the discharge conduit 211 by sliding the metering body 215. In the full flow position, the metering conduit 218 is completely in abutment with the discharge conduit 211, and in the fully closed position, the metering conduit 218 is not in abutment with the discharge conduit 211 at all, so that the oil 103 in the collection space 251 cannot reach the discharge conduit 211. By positioning the metering body 215 in a position between the full flow position and the fully closed position, the amount of oil 103 that can reach the discharge conduit 211 from the collection space 251 can be metered.

[0048] The use of metering devices such as metering devices 112a, 112b and 212 helps to evenly distribute the oil 103 over the entire width of the deep frying pan 101, regardless of the pressure in the pressure chamber 151 or 251. In this way, vortices generated by the oil 103 in the deep frying pan 101 can be counteracted and the uniform heating of the oil 103 in the deep frying pan 101 is improved, so that the food products conveyed in the oil 103 by the conveyor and located on the conveyor belt 102 are treated the same, partly because they have the same residence time in the oil 103.

[0049] The invention is not limited to the above-described embodiments. In alternative embodiments, for example, the metering device may comprise two metering bodies instead of a single metering body, wherein the two metering bodies are aligned with each other and driven in a similar manner, for example by two synchronous drive devices. Such an embodiment may be particularly advantageous for relatively wide frying pans, for example frying pans of 2 or even 3 meters wide. If, for example, the length of the cylindrical metering body 115 is 3 meters, there is a risk that unfavorable torsion phenomena may occur.

[0050] In a further alternative embodiment, the deep frying pan may be larger than FIG. Figure 1a In this case, there is only a single metering device instead of two metering devices 112a, 112b, and only a single combination of discharge port and discharge line instead of two such combinations, such as the combination of discharge ports 106a, 106b and discharge lines 107a, 107b. The discharge port of this alternative embodiment, such as discharge port 106c, will be located Figure 1a The position of the middle discharge port 106b.

[0051] The invention can be used in a particularly suitable manner for treating potato products with oil, but other types of food, such as peanuts and fish or meat products, can also be advantageously treated with oil by means of the system according to the invention.

Claims

1. A system for treating food with oil, comprising: - a container for oil provided with a bottom; - conveying means for conveying the food to be treated through the oil in the container in a conveying direction, the conveying means comprising an endless conveyor belt wound around guide rollers arranged at opposite ends of the system so that the food is located on the carrying path of the conveyor belt; - supply means for supplying oil to said container; - a drain device for draining the oil from said container; - heating means for heating said oil; The supply device comprises: - at least two supply bodies, viewed from the conveying direction, the at least two supply bodies are arranged at a certain distance, each supply body comprising: - an elongated collecting space for the oil, wherein the longitudinal direction of the collecting space extends transversely to the conveying direction, and - at least two supply ducts, wherein each supply duct adjoins said collecting space on its respective upstream side and ends on its respective downstream side in said bottom portion of said container via an outlet opening of a respective supply duct, - a pump for supplying the collecting space with oil heated by the heating device, and - metering means for metering the amount of oil supplied to said outlet opening, The metering device has a channel opening on each supply duct, which is arranged between the respective supply duct and the collecting space, through which oil can flow from the collecting space into the supply duct, and wherein the size of each channel opening is adjustable.

2. The system according to claim 1, wherein: The outlet openings are arranged in a row.

3. The system according to claim 2, wherein: The rows extend in a horizontal direction and transversely to the conveying direction.

4. The system according to claim 2, wherein: The metering device comprises at least one metering body having a metering channel corresponding to each supply conduit, wherein a free-flowing portion of the metering channel forms a channel opening, and wherein the at least one metering body is movable relative to at least one supply conduit to adjust a size of the at least one channel opening according to a metering position.

5. The system according to claim 4, wherein: Regardless of the metering position used, the dimensions of the individual passage openings are the same.

6. The system according to claim 4 or 5, wherein: The metering body is rotatable relative to the at least one supply line about an axis of rotation.

7. The system according to claim 6, wherein: The rotation axis extends parallel to the rows.

8. The system according to claim 6, wherein: The metering body has an at least partially circular cross section.

9. The system according to claim 6, wherein: The metering body has a completely circular cross section.

10. The system according to claim 8 or 9, wherein: At least one metering channel extends between two radially opposite sides of the at least partially circular cross-section.

11. The system according to claim 4, wherein: The metering body is slidable relative to the at least one supply duct.

12. The system according to claim 11, wherein: The metering body slides relative to at least one supply duct parallel to the row.

13. The system according to claim 11 or 12, wherein: The measuring body is in the shape of a bar.

14. The system of claim 1, wherein: The container has a width and the collecting space has a length at least equal to 85% of the width of the container.

15. The system of claim 1, wherein: The system comprises two supplies aligned with each other.

16. The system of claim 4, wherein: The system comprises two measuring bodies which are aligned with each other.

17. The system of claim 4, wherein: The system has a servomotor for driving the displacement of the at least one metering body between the metering positions.

18. The system according to claim 1, wherein the outlet opening associated with at least one of the at least two feed bodies is arranged at a distance from an opposite end of the bottom portion, viewed in the conveying direction.

19. The system of claim 1, wherein the outlet opening associated with each of the at least two feeds is arranged at a distance from opposite ends of the bottom portion, viewed in the conveying direction.

20. The system of claim 1, wherein: The discharge device comprises at least one discharge opening in the bottom of the container and at least one discharge line connected to the at least one discharge opening.

21. The system of claim 20, wherein: The discharge device comprises at least two discharge openings in the bottom of the container, the at least two discharge openings being arranged at a distance from each other as viewed in the conveying direction.

22. The system of claim 21, wherein: The at least two discharge openings arranged at a distance in the bottom of the container are also arranged at a distance from opposite ends of the bottom, viewed in the conveying direction.

23. A system according to claim 20, 21 or 22, wherein: The discharge opening is arranged upstream of at least one of the outlet openings, viewed in the conveying direction.

24. The system of claim 1, wherein: The outlet opening associated with at least one of the at least two feed bodies is arranged in a region between 25% and 75% of the distance between opposite ends of the bottom.

25. The system of claim 1, wherein: The outlet opening associated with each of the at least two feeds is arranged in a region between 25% and 75% of the distance between opposite ends of the bottom.

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