Heat treatment apparatus and method for heat treatment of food materials

Abstract

To appropriately heating and filling a food material, without using a dummy liquid.SOLUTION: A heat treatment apparatus comprises: a heating device 40; a heating channel in which the heating device 40 is arranged; a branch channel branching from the heating channel; a filling channel communicating with the filling device 140; a pressure device 110 for supplying pressurized air to the filling channel; a switching valve 70 having a first position communicating the heating channel and the branch channel, and a second position communicating the heating channel and the filling channel; and a control unit 150. The control unit 150 performs a heating start-up step in which the food material is transferred with the switching valve 70 in the first position until the heating device 40 stably operates, and, after stable operation of the heating device 40, an actual operation preparation step of transferring the food material to the filling channel pressurized by the pressurizing device 110 with the switching valve 70 in the second position, and an actual operation step of stopping pressurizing by the pressure device 110 when the food material reaches a predetermined position in the filling channel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heat treatment apparatus and a method for heat-treating food materials.

Background Art

[0002] As a heat treatment apparatus for heating a food material having fluidity for sterilization or cooking, while continuously transferring the food material in a pipe, by directly energizing the food material using the electric resistance of the food material, a heat treatment apparatus using a heating technique (electric heating, Joule heating) that causes the food material itself to generate heat has been put into practical use (for example, Patent Document 1). In such an electric heating apparatus, the food material is also heated to a target temperature exceeding 100°C (for example, 121°C) for sterilization or cooking.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Because fluid food materials are mostly composed of water, heating them to temperatures above 100°C requires pressurizing the flow path. Conventionally, to pressurize the flow path, a dummy liquid (such as saline solution or citric acid solution) other than the food material was circulated before the food material was introduced. This dummy liquid filled the flow path, creating a pressurized state, and once it was heated to a target temperature above 100°C, the food material was introduced. However, this method had several problems: it required a large amount of dummy liquid, resulting in high costs; a large amount of dummy liquid was wasted; and components in the dummy liquid (such as salt or citric acid) could contaminate the food material that subsequently flowed through it.

[0005] The present invention aims to provide a heat treatment apparatus and a heat treatment method for food materials that can appropriately heat and fill food materials without using a dummy liquid. [Means for solving the problem]

[0006] The heat treatment apparatus according to the present invention comprises a transfer device for transferring a fluid food material, a heating device for heating the food material, a heating channel in which the heating device is located, a branch channel branching from the heating channel, a filling channel communicating with a filling device, a pressurizing device for supplying pressurized air to the filling channel, a switching valve having a first position communicating the heating channel and the branch channel, and a second position communicating the heating channel and the filling channel, and a control unit for controlling the operation of the transfer device, the heating device, the switching valve, and the pressurizing device. The filling channel includes a cooling unit and a filling channel back pressure valve or a single-screw eccentric pump located on the filling device side of the cooling unit, and the pressurizing device pressurizes the filling channel between the switching valve and the filling channel back pressure valve or single-screw eccentric pump located on the filling device side.The control unit performs a heating start-up step in which the switching valve is set to a first position and the food material is transferred until the heating device is in stable operation; a preparation step for full operation in which the switching valve is set to a second position and the food material is transferred to the filling channel pressurized by the pressurizing device after the heating device is in stable operation; and a full operation step in which the pressurizing device stops pressurizing when the food material reaches a predetermined position in the filling channel. The heating device is a Joule heating device that heats the food material by applying an electric current. In the above-described heating apparatus, the control unit may be configured to heat the food material to a temperature higher than 100°C using the heating device during the heating start-up step. In the above-described heat treatment apparatus, a sterilization filter may be provided between the pressurizing device and the filling channel. In the above-described heating apparatus, a filling channel back pressure valve is further provided in the filling channel, and the filling channel can be pressurized by supplying pressurized air from the pressurizing device to the channel between the switching valve and the filling channel back pressure valve. In the above-described heating apparatus, the control unit may be configured to stop pressurizing by the pressurizing device when the food material reaches the back pressure valve of the filling channel during the main operation step. In the above-described heat treatment apparatus, a uniaxial eccentric screw pump is further provided in the filling passage, and the filling passage can be pressurized by supplying pressurized air from the pressurizing device to the passage between the switching valve and the uniaxial eccentric screw pump. In the above-described heating apparatus, the control unit may be configured to stop pressurizing by the pressurizing device when the food material reaches the uniaxial eccentric screw pump during the main operation step. In the above-described heating apparatus, the filling channel has a cooling section for cooling the food material heated by the heating device, and the main operation step can be configured to stop pressurizing by the pressurizing device when the food material reaches a position beyond the cooling section of the filling channel. The heat treatment method according to the present invention is a heat treatment method using the heat treatment apparatus described above, wherein until the heating apparatus is in stable operation, a heating start-up step is performed in which the switching valve is set to the first position and the food material is transferred; after the heating apparatus is in stable operation, a main operation preparation step is performed in which the switching valve is set to the second position and the food material is transferred to the filling channel pressurized by the pressurizing device; and a main operation step is performed in which the pressurizing by the pressurizing device is stopped when the food material reaches a predetermined position in the filling channel. In the above heat treatment method, a filling channel back pressure valve is provided in the filling channel, and the filling channel can be configured to be pressurized by supplying pressurized air from the pressurizing device to the channel between the switching valve and the filling channel back pressure valve. In the above heat treatment method, a uniaxial eccentric screw pump is provided in the filling passage, and the filling passage can be pressurized by supplying pressurized air from the pressurizing device to the passage between the switching valve and the uniaxial eccentric screw pump. [Effects of the Invention]

[0007] According to the present invention, since food materials can be transferred to a pressurized filling channel by a pressurizing device, food materials can be properly heated and filled without using a dummy liquid. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the configuration of the heat treatment apparatus according to the first embodiment. [Figure 2] This is an enlarged view of the main parts around the switching valve of the heat treatment apparatus according to the first embodiment. [Figure 3] This is a diagram showing the configuration of an electrically heated device according to the first embodiment. [Figure 4] This is a diagram showing the configuration of the heating module according to the first embodiment. [Figure 5] This is an enlarged cross-sectional view of the heating module according to the first embodiment. [Figure 6] This is a diagram showing the configuration of the heat treatment apparatus according to the second embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the heat treatment apparatus and the heat treatment method for food materials according to the present invention will be described with reference to the drawings. In the following embodiments, a Joule heating apparatus is used as an example of the heat treatment apparatus according to the present invention, which heats the food material by applying a voltage to an electrode body that forms a flow path for the food material (Joule heating). However, the invention is not limited to a Joule heating apparatus and can be applied to other heat treatment apparatuses, such as those that heat by heat exchange. Furthermore, the food material to be heated in this embodiment is not particularly limited as long as it is a fluid food material, and can be heated from soft drinks, liquid substances such as liquid seasonings and liquid sauces that do not contain solids, gel-like substances such as jams, and mixtures of solids and liquids such as tapioca drinks and cooking sauces that contain solids (for example, chopped vegetables). However, as will be described later, the heating apparatus according to the first embodiment is suitable for liquid or gel-like food materials that mainly do not contain solids or contain only solids of a certain size or smaller (for example, solids with an average particle size of less than 3 mm or less than 1 mm), because it uses a back pressure valve with a relatively narrow internal flow path. The heating apparatus according to the second embodiment is suitable for liquid or gel-like materials that contain solids of a certain size or larger (for example, solids with an average particle size of 1 mm or more, or 3 mm or more, or 5 mm or more), because it uses a single-screw eccentric pump with a relatively wide internal flow path. This is because the configuration using a back pressure valve has the problem of clogging by solids.

[0010] ≪First Embodiment≫ Figure 1 is a diagram showing the configuration of the heat treatment apparatus 1 according to the first embodiment. The heat treatment apparatus 1 is a group of devices for heating and sterilizing food materials by Joule heating and filling the heated food materials into bags or containers. As shown in Figure 1, it includes a raw material tank 10, a pump 20, a preheating unit 30, an energized heating device 40, a temperature sensor 50, a temperature holding unit 60, a switching valve 70, a first cooling unit 80, a first back pressure valve 90, a sterilization filter 100, a pressurized air source 110, a second cooling unit 120, a second back pressure valve 130, and a filling machine 140.

[0011] Furthermore, as shown in Figure 1, the raw material tank 10, pump 20, preheating unit 30, electric heating device 40, temperature holding unit 60, switching valve 70, first cooling unit 80, first back pressure valve 90, second cooling unit 120, second back pressure valve 130, and filling machine 140 are connected by pipes 11-18 and 21-23. In this embodiment, as shown in Figure 2, the flow path from the electric heating device 40 to the switching valve 70 (including pipe 14, temperature holding unit 60, and pipe 15) is described as the first flow path 31, the flow path from the switching valve 70 to the first back pressure valve 90 is described as the second flow path 32, and the flow path from the switching valve 70 to the second back pressure valve 130 is described as the third flow path 33. Figure 2 is an enlarged view of the main parts around the switching valve 70.

[0012] In the heat treatment apparatus 1 according to this embodiment, food materials stored in the raw material tank 10 are sterilized or cooked by Joule heating and then filled into bags or containers by the filling machine 140. When sterilizing food materials, they need to be heated to a predetermined sterilization temperature. However, immediately after the start of heating, the heating by the electric heating device 40 is not stable, and the food materials heated by the electric heating device 40 may be transferred downstream at a temperature lower than the predetermined sterilization temperature. If such food materials that have not been completely sterilized are passed through the second cooling unit 120 or the filling machine 140 downstream of the electric heating device 40, there is a risk that the food materials will be filled with surviving bacteria.

[0013] Therefore, in this embodiment, until the temperature of the food material heated by the electric heating device 40 stabilizes, the food material is not circulated to the second cooling unit 120 or the filling machine 140, but is instead circulated to a different flow path. Specifically, the heating apparatus 1 has a switching valve 70 downstream of the electric heating device 40 that switches the flow path of the food material. By operating the switching valve 70 so that pipe 15 and pipe 16 are in communication (setting the switching valve 70 to the first position), the first flow path (heating flow path) 31 and the second flow path (branching flow path) 32 can be connected. Also, by operating the switching valve 70 so that pipe 15 and pipe 21 are in communication (setting the switching valve 70 to the second position), the first flow path 31 (heating flow path) and the third flow path (filling flow path) 33 can be connected. In this embodiment, as shown in Figure 2, the path through which the heated food material returns to the raw material tank 10 via the first channel 31 and the second channel 32 is referred to as the start-up path 2, and the path through which the heated food material is transferred to the filling machine 140 via the first channel 31 and the third channel 33 is referred to as the main operation path 3. In this embodiment, by controlling the operation of the switching valve 70 with the control unit 150, a heating start-up step is performed in which the food material heated by the electric heating device 40 is circulated through the start-up path 2, which returns to the raw material tank 10 via the first channel 31 and the second channel 32, until the heating of the electric heating device 40 stabilizes. After the heating of the electric heating device 40 stabilizes, a main operation preparation step and a main operation step are performed in which the food material heated by the electric heating device 40 is circulated through the main operation path 3, which transfers it to the filling machine 140 via the first channel 31 and the third channel 33.

[0014] Here, when sterilizing a fluid food material at a temperature higher than 100°C, it is necessary to increase the pressure in the flow path to a temperature exceeding 100°C higher than the atmospheric pressure. In the first embodiment, by using the first backpressure valve 90 and the second backpressure valve 130 whose valves are not opened until a certain pressure is reached, the flow path from the pump 20 that pumps the food material to the first backpressure valve 90 and the flow path from the pump 20 to the second backpressure valve 130 can be set to a pressure higher than the atmospheric pressure. For example, during the circulation operation in which the start-up path 2 is circulated through the food material, the food material is transferred at a constant pressure by the pump 20, and the pressure on the side of the energization heating device 40 (primary side) is adjusted to a pressure higher than the atmospheric pressure by the first backpressure valve 90, so that the pressure in the flow path between the pump 20 and the first backpressure valve 90 is set to a pressure higher than the atmospheric pressure.

[0015] Also, in the present embodiment, before switching from the start-up path 2 to the main operation path 3 (before the first flow path 31 and the third flow path 33 are connected), compressed air is supplied from the compressed air source 110 into the third flow path 33 to pre-pressurize the inside of the third flow path 33. As a result, even immediately after switching from the start-up path 2 to the main operation path 3, the main operation path 3 including the heating flow path 48 is maintained in a pressurized state, and it becomes possible to transfer the food material heated to a temperature higher than 100°C through the pressurized main operation path 3. As a result, it becomes possible to appropriately perform the heat treatment of the food material only with the food material without using a dummy liquid. Hereinafter, each device constituting the heat treatment device 1 will be described.

[0016] The raw material tank 10 has, for example, a kneader function and can store food materials while stirring (or mixing, formulating) them. The food materials stored in the raw material tank 10 are transferred at a constant speed downstream by the pump 20 via the pipes 11 and 12. When the food materials transferred from the raw material tank 10 pass through the preheating section 30, they are heated from room temperature to about 20 to 80 °C and transferred to the electric heating device 40 through the pipe 13. The preheating section 30 can preheat the food materials transferred to the electric heating device 40 by circulating warm water outside the wall surface of the flow path through which the food materials pass. Also, it is possible to directly transfer the food materials from the raw material tank 10 to the electric heating device 40 without providing the preheating section 30, or the raw material tank 10 can have a preheating function.

[0017] The electric heating device 40 is a Joule heating device that directly energizes the food materials by utilizing the electrical resistance of the food materials, causing the food materials themselves to generate heat. The electric heating device 40 can appropriately adjust the heating temperature of the food materials flowing through the electric heating device 40 by appropriately adjusting the voltage applied to the food materials and the length of the heating flow path. FIG. 3 is a configuration diagram of the electric heating device 40 according to the present embodiment. As shown in FIG. 3, the electric heating device 40 according to the present embodiment has three heating modules 41, and the heating modules 41 are communicated with each other via a pipe 42.

[0018] Also, FIG. 4 is a configuration diagram of the heating module 41. As shown in FIGS. 3 and 4, the heating module 41 includes a plurality of electrode bodies 43 arranged alternately and a plurality of spacer pipe bodies 44, and these are clamped and fixed by a flange 45. The inner diameters of the electrode bodies 43 and the spacer pipe bodies 44 are the same, and a heating flow path 48 for subjecting the food materials to electric heating treatment is formed by connecting and communicating them alternately.

[0019] The electrode body 43 is preferably ring-shaped, but there are no particular restrictions on its shape, such as polygonal or elliptical. The ring-shaped electrode body 43 has an inner surface shape that matches the spacer tube 44, and by arranging the spacer tubes 44 alternately, an electrical circuit is formed and heated by current flow when food material passes between each electrode body 43. The electrode body 43 is made of a highly conductive material, and metals such as aluminum, aluminum alloy, titanium, titanium alloy, platinum, pure iron, and stainless steel can be used. The two electrode bodies provided near both ends of the heating channel 48 are ground electrodes 46 for preventing leakage current, and the remaining electrode bodies 43 sandwiched between the ground electrodes 46 are all for current flow heating.

[0020] The spacer tubes 44 are made of an insulating material and are arranged alternately with the electrode bodies 43 to form a heating channel 48. The spacer tubes 44 are made of non-conductive plastics, such as polytetrafluoroethylene, polyetheretherketone, polyetherimide, or polysulfone. The shape of the spacer tubes 44 is not limited; they may be rectangular cylinders or cylinders with a circular inner surface and a rectangular outer surface. However, it is necessary that the cross-sectional shape of the spacer tubes 44 corresponds to the cross-sectional shape of the electrode bodies 43. A sealing material is incorporated between the connection surfaces of the spacer tubes 44 and the electrode bodies 43 to prevent food material from leaking out of the heating channel 48. The length of the spacer tubes 44 becomes the distance between the electrodes. Preferably, the ratio (L / R) of the distance L between the electrodes to the inner diameter R of the electrode body 43 (diameter of the heating channel 48) is 2 times or more, and more preferably 4 times or more and 12 times or less, to promote uniform heating.

[0021] Joint sections 47 are provided at both ends of the heating channel 48, one for the inlet side and the other for the outlet side. Each electrode 43 is connected to the power supply unit 160 such that adjacent electrode 43s have opposite polarity in the direction of flow of the food material. The number of electrode 43 provided in the heating module 41 can be arbitrarily set according to the heating temperature, etc.

[0022] Figure 5 is an enlarged cross-sectional view of the heating module 41, showing the cross-section of the heating module 41 at the position of the electrode body 43. The electrode body 43 has a medium channel 49 through which the medium flows, concentrically arranged along the inner surface of the heating channel 48. The medium flowing through the medium channel 49 is supplied from a medium supply port 410 provided on the electrode body 43 and discharged from a medium discharge port 411 provided on the opposite side. In this embodiment, any of the following can be selected as the medium supplied to the medium channel 49: cold water at a temperature lower than room temperature, water at room temperature, or hot water at a temperature higher than room temperature.

[0023] Food materials that have been heated, sterilized or cooked in the electrically heated device 40 are transferred via pipe 14 to the temperature holding unit 60, where they are further heated and sterilized by preheating. The food materials that have been heated and sterilized in the temperature holding unit 60 are then transferred via pipe 15 to the switching valve 70.

[0024] Furthermore, as shown in Figure 1, a temperature sensor 50 is provided near the outlet of the electric heating device 40 to measure the temperature of the central axis portion of the flow path in the pipe 14. The temperature sensor 50 according to this embodiment measures the temperature of the food material near the outlet of the electric heating device 40 every second and outputs the acquired temperature data to the control unit 150. Note that the period for measuring the temperature by the temperature sensor 50 is not limited to every second, and may be shorter or longer than one second. Also, a known temperature sensor such as a thermocouple can be used as the temperature sensor 50.

[0025] The control unit 150 includes a processing unit that executes a control program that controls the voltage applied to the electrode body 43 based on temperature data, and a storage device that stores the control program and the temperature data acquired from the temperature sensor 50. Based on the temperature data acquired by the temperature sensor 50, the control unit 150 controls the output of the electric heating device 40 (the voltage applied to the electrode body 43). Specifically, if the temperature of the food material acquired by the temperature sensor 50 has not reached the target temperature, the control unit 150 increases the voltage applied to the electric heating device 40 to raise the temperature of the food material to the target temperature. Conversely, if the temperature of the food material measured by the temperature sensor 50 exceeds the target temperature, the control unit 150 decreases the voltage applied to the electric heating device 40 to lower the temperature of the food material to the target temperature. In this way, the control unit 150 performs feedback control of the voltage applied to the electrode body 43 based on the temperature data of the food material measured by the temperature sensor 50.

[0026] Furthermore, during normal operation, the control unit 150 can automatically control the power supplied to the electrode body 43 using PID control based on the measurement value of the temperature sensor 50. The values ​​of proportional action (P action) and integral action (I action) in the PID control are appropriately and optimally set according to the total length of the heating channel 48 and the flow rate of the food material, etc., so as not to cause overshoot or cycling. In addition, in this embodiment, the temperature sensor 50 is installed near the outlet of the energized heating device 40, but in addition to this configuration, another temperature sensor can also be installed near the inlet of the energized heating device 40, in the piping 42 between the first heating module 41 and the second heating module 41, or in the piping 42 between the second heating module 41 and the third heating module 41.

[0027] Furthermore, in this embodiment, the control unit 150 has the function of controlling the flow path of food materials by operating the switching valve 70. In this embodiment, as the flow path of food materials heated by the electric heating device 40 and the temperature holding unit 60, a rise path 2 is set up in which the food materials transferred to the switching valve 70 are returned to the raw material tank 10 via the first cooling unit 80 and the first back pressure valve 90, and a main operation path 3 is set up in which the food materials are transferred to the filling machine 140 via the second cooling unit 120 and the second back pressure valve 130. The switching valve 70 is, for example, a three-way valve, and under the control of the control unit 150, as shown in Figure 2, it can be operated to connect the first flow path 31 in pipe 15 and the second flow path 32 in pipe 16 so that the food materials flow through the rise path 2, and it can also be operated to connect the first flow path 31 in pipe 15 and the third flow path 33 in pipe 21 so that the food materials flow through the main operation path 3.

[0028] In this case, the heat treatment device 1 may not stabilize at a predetermined sterilization temperature immediately after heating begins. However, even in such cases, after some time has passed (for example, about 1 minute after heating begins in the heat treatment device 1), the first flow path 31 becomes sufficiently pressurized, and the food material can be stably heated to a temperature above the sterilization temperature. However, if the food material is transferred to the second cooling unit 120 and the filling machine 140 while it is still at a temperature lower than the predetermined sterilization temperature, bacteria that have survived will enter the second cooling unit 120 and the filling machine 140, resulting in the need not only to discard the filled food material but also to re-sterilize and clean the second cooling unit 120 and the filling machine 140. Therefore, in this embodiment, until the heating temperature in the energized heating device 40 stabilizes, the control unit 150 uses the switching valve 70 to circulate the food material through the riser path 2. Then, once the heating temperature in the energized heating device 40 stabilizes, the control unit 150 switches the switching valve 70 to perform a filling operation that allows the food material to flow through the main operating path 3. The control unit 150 can also be configured to determine whether the heating temperature of the food material has stabilized based on the temperature of the food material measured by the temperature sensor 50 and control the switching valve 70, or it can be configured to determine that the heating temperature of the food material has stabilized after a certain period of time has elapsed since the start of heating and control the switching valve 70.

[0029] Here, when the switching valve 70 is switched to allow the food material heated by the energized heating device 40 to flow into the main operating path 3 (from the first flow path 31 to the third flow path 33), if the pressure from the switching valve 70 to the second back pressure valve 130 is at atmospheric pressure, immediately after switching the switching valve 70, the pressure in the main operating path 3, including the heated flow path 48 which was under pressurization, drops, and it may not be possible to heat the food material in the heated flow path 48 to a target temperature exceeding 100°C. In addition, the food material heated to a temperature higher than 100°C that flows into the third flow path 33 may boil over when exposed to atmospheric pressure, and the flow velocity of not only the food material flowing through the third flow path 33 but also the subsequent food material flowing through the first flow path 31 increases. As a result, in some cases, the energized heating time in the heated flow path 48 is insufficient, and the food material may not be heated to the target temperature.

[0030] In contrast, in this embodiment, before the control unit 150 connects the first flow path 31 and the third flow path 33, it supplies compressed air from the pressurized air source 110 to the third flow path 33, keeping the third flow path 33 pressurized. This allows the main operating path 3, including the heating flow path 48, to remain pressurized even immediately after switching the switching valve 70, enabling the food material to be continuously heated to a target temperature exceeding 100°C. Furthermore, by keeping the third flow path 33 pressurized by the pressurized air source 110, even if food material heated to a temperature higher than 100°C flows into the third flow path 33, it is possible to prevent the food material from boiling over. As a result, the change in the flow velocity of the food material due to boiling over as described above can be prevented, and the energizing time of the food material in the heating flow path 48 can be kept constant, thus enabling the food material to be heated appropriately.

[0031] The pressurized air source 110 is an air compressor or the like, which takes in air from the outside, compresses the taken-in air, and sends it to the third flow path 33. The pressurized air source 110 is also controlled on / off based on the control of the control unit 150. The compressed air blown from the pressurized air source 110 is sent to the third flow path 33 via the sterilization filter 100. The sterilization filter 100 is a filter that prevents bacteria and germs from passing through, allowing only air to pass through, so that the compressed air supplied from the pressurized air source 110 is provided to the third flow path 33 in a sterile state. In this embodiment, by providing the second back pressure valve 130 on the main operating path 3, the flow path between the switching valve 70 and the second back pressure valve 130 (not only the third flow path 33, but also the flow path in the second cooling unit 120 and the flow path in the pipe 22) can be pressurized by providing compressed air from the pressurized air source 110 to the third flow path 33.

[0032] Furthermore, when the food material is transferred to the second back pressure valve 130, the flow path from the pump 20 to the second back pressure valve 130 is filled with the food material, and the flow path becomes under constant pressure. In this state, it is no longer necessary to supply compressed air from the pressurized air source 110 into the third flow path 33, so the control unit 150 stops supplying compressed air from the pressurized air source 110. The control unit 150 can determine whether the food material has reached the second back pressure valve 130, for example, by using a flow sensor installed near the second back pressure valve 130.

[0033] The food material passing through pipe 21 (third flow path 33) is transferred to the second cooling section 120. In the second cooling section 120, the heated food material is cooled to a temperature suitable for filling. The second cooling section 120 can cool the food material being transferred to the filling machine 140 by, for example, circulating a coolant on the outside of the wall surface of the flow path through which the food material passes. The food material cooled in the second cooling section 120 is then transferred to the filling machine 140 via pipe 22, the second back pressure valve 130, and pipe 23.

[0034] The filling machine 140 is equipped with a nozzle for filling the bag with food material and a molding machine for shaping the food material filled in the bag. The filling machine 140 is also equipped with a hopper, which can temporarily store the food material transferred from the electrically heated device 40.

[0035] As described above, the heating apparatus 1 according to this embodiment includes an electric heating device 40 for heating food material, a switching valve 70 for switching the flow path of food material, and a control unit 150 for controlling the switching operation of the switching valve 70. The control unit 150 performs a heating start-up step in which it transfers food material with the switching valve 70 in a first position so that the first flow path 31, which is the flow path from the electric heating device 40 to the switching valve 70, and the second flow path 32, which allows the flow of unsterilized food material, are in communication until heating by the electric heating device 40 stabilizes. After the electric heating device 40 has stabilized, it performs a preparation step for full operation in which it transfers food material to the third flow path 33, which is pressurized by the pressurizing device 110, with the switching valve 70 in a second position. When the food material reaches the second back pressure valve 130, it performs a full operation step in which it stops pressurizing by the pressurizing device 110. As a result, in the heating apparatus 1 according to this embodiment, when the first flow path 31 and the third flow path 33 are connected, the main operating path 3, including the heating flow path 48, can be kept under pressure without filling it with dummy liquid and creating a pressurized state. Therefore, food materials can be continuously heated under pressurized conditions, and it is possible to heat the food materials to a target temperature exceeding 100°C. In addition, since there is no need to use dummy liquid, it is possible to reduce the cost associated with dummy liquid, prevent the disposal of dummy liquid, and prevent the contamination of food materials with components of dummy liquid.

[0036] Furthermore, when the food material heated by the electric heating device 40 is flowed through the main operating path 3 (from the first flow path 31 to the third flow path 33), if the pressure from the switching valve 70 to the second back pressure valve 130 is at atmospheric pressure, the food material heated to a temperature higher than 100°C will boil over when exposed to atmospheric pressure. This will increase the flow rate not only of the food material flowing through the third flow path 33 but also of the food material flowing through the subsequent first flow path 31, potentially preventing some food material from being heated for a sufficient amount of time and thus failing to reach the target temperature. However, in this embodiment, by pressurizing the flow path from the switching valve 70 to the second back pressure valve 130 with the pressurized air source 110, the main operating path 3, including the heating flow path 48, can be maintained in a pressurized state. This prevents sudden boiling of the food material and suppresses changes in the flow velocity of the food material due to sudden boiling. As a result, the food material can be passed through the heating flow path 48 at a constant speed and heated by electric current for a certain period of time, and the food material being sequentially transferred to the heating flow path 48 can be heated to a target temperature exceeding 100°C without interruption.

[0037] Furthermore, in the heat treatment apparatus 1 according to this embodiment, when the food material has flowed through the third flow path 33 to the second back pressure valve 130, the supply of compressed air from the pressurized air source 110 is stopped, allowing the pressurized air source 110 to be pressurized only when necessary, thereby reducing the running costs for heating and sterilizing the food material. In addition, the heat treatment apparatus 1 according to this embodiment can pressurize the first flow path 31, the second flow path 32, and the third flow path 33 with a relatively inexpensive and simple configuration by using the first back pressure valve 90 and the second back pressure valve 130.

[0038] ≪Second Embodiment≫ Next, the heating apparatus 1a according to the second embodiment will be described. The heating apparatus 1a according to the second embodiment has the same configuration as the heating apparatus 1 according to the first embodiment and operates in the same manner, except that it has a first single-screw eccentric pump 170 and a second single-screw eccentric pump 180 instead of the first back pressure valve 90 and the second back pressure valve 130. In the following, the same configuration as the heating apparatus 1 according to the first embodiment will be omitted from the description. In the following, the first single-screw eccentric pump 170 and the second single-screw eccentric pump 180 will also be described simply as single-screw eccentric pumps 170 and 180.

[0039] Here, although the first back pressure valve 90 and the second back pressure valve 130 according to the first embodiment have a simple structure and are relatively inexpensive, their internal flow paths are narrow, and when the food material is a liquid or gel containing solids of a certain size or larger (for example, solids with an average particle size of 1 mm or more, or 3 mm or more, or 5 mm or more), such food material may not be able to pass through the first back pressure valve 90 and the second back pressure valve 130, or the solids may be crushed in the first back pressure valve 90 and the second back pressure valve 130, making it undesirable to apply the heat treatment apparatus 1 according to the first embodiment.

[0040] In contrast, in the heating apparatus 1a according to the second embodiment, a first uniaxial eccentric screw pump 170 is installed in the startup path 2, and a second uniaxial eccentric screw pump 180 is installed in the main operation path 3. The uniaxial eccentric screw pumps 170 and 180 are pumps that can deliver food materials by rotating an eccentric screw about an axis in the same direction as the internal flow path. Compared to the back pressure valves 90 and 130 according to the first embodiment, the uniaxial eccentric screw pumps 170 and 180 according to the second embodiment have a wider internal flow path, so they can pass food materials containing solids of 1 mm or more (or 3 mm or more, or 5 mm or more). For example, the NHLA type of Heishin Mono Pump (registered trademark) (manufactured by Heishin Equipment Co., Ltd.) can be used as the uniaxial eccentric screw pumps 170 and 180 according to the second embodiment. Furthermore, in the NHLA type single-screw eccentric pump of Heishin Mono Pump, the internal flow path of the single-screw eccentric pumps 170 and 180 can be narrowed by pressing the outer circumference constituting the flow path with pressurized air from the outside, and the internal flow path of the single-screw eccentric pumps 170 and 180 can be widened by reducing or stopping the application of pressurized air to the outer circumference, thus making it easier to clean the internal flow path of the single-screw eccentric pumps 170 and 180. In the second embodiment as well, the control unit 150 can be configured to determine whether the food material has reached the second single-screw eccentric pump 180, for example, by using a flow sensor installed near the second single-screw eccentric pump 180, and if it determines that the food material has reached the second single-screw eccentric pump 180, it can be configured to stop the supply of compressed air from the pressurized air source 110.

[0041] Although preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the embodiments described above. Various modifications and improvements can be made to the above embodiments, and such modified or improved forms are also included within the technical scope of the present invention.

[0042] For example, in the embodiment described above, a configuration is illustrated in which a switching valve 70 is provided and this switching valve 70 is controlled to switch between the heating rise path 2 and the main operation path 3. However, the configuration is not limited to this, and for example, a configuration can be made that does not have a switching valve 70 or a rise path 2, but only has the main operation path 3. In this case, by pressurizing the main operation path 3 (for example, the flow path from the pump 20 to the second back pressure valve 130) with a pressurized air source 110, the main operation path 3, including the heating flow path 48, can be kept pressurized without using a dummy liquid, making it possible to heat the food material in the heating flow path 48 to a target temperature exceeding 100°C.

[0043] Furthermore, although the above-described embodiment illustrates a configuration having a first cooling section 80 and a second cooling section 120, a configuration without the first cooling section 80 and / or the second cooling section 120 is also possible. In this case, the food material heated by the electrically heated device 40 will be cooled as it passes through the pipe 16 or pipe 21. Note that the "cooling section" in the present invention is not limited to the second cooling section 120, but includes parts where cooling is performed by heat dissipation, such as the pipe 21.

[0044] Furthermore, in the above-described embodiment, a startup path 2 was illustrated in which the food material is returned to the raw material tank 10 via pipe 18 until the temperature of the heated food material stabilizes. However, the configuration is not limited to this, and the food material heated by the electric heating device 40 can be discharged to the outside via the second flow path 32 until the temperature of the heated food material stabilizes. Also, the temperature holding unit 60 is not essential, and the configuration can be made without a temperature holding unit 60. Moreover, even after the temperature of the food material has stabilized, the temperature of the food material may become unstable due to insufficient stirring or mixing errors of the food material introduced into the raw material tank 10 during operation, and the target sterilization temperature may not be achieved. In such cases, the control unit 150 can be configured to control the switching valve 70 so as to switch the flow path through which the food material flows from the main operation path 3 to the startup path 2.

[0045] Furthermore, while the above-described embodiment illustrates a configuration in which a sterilization filter 100 and a pressurized air source 110 are provided between the switching valve 70 and the second cooling unit 120, the configuration is not limited to this, and a configuration in which the sterilization filter 100 and a pressurized air source 110 are provided between the second cooling unit 120 and the second back pressure valve 130 is also possible. In addition to the above-described embodiment, if the food material contains solid matter or other materials with low fluidity, a mono pump or the like can be provided on the filling machine 140 side of the main operating path 3, rather than on the switching valve 70 side.

[0046] In addition, although the above-described embodiment illustrates a configuration in which the electrode body 43 is ring-shaped, the configuration is not limited to this, and for example, the electrode body 43 can be configured as a flat plate. For example, when performing electric heating by an AC high-electric field sterilization method, a flat plate-shaped electrode body 43 can be used, and this electrode body 43 can be heated and cooled with a medium. [Explanation of Symbols]

[0047] 1,1a... Heat treatment apparatus 10… Raw material tank 20... Pump 30… Preheating section 40…Electric heating device 41…Heating module 42... Piping 43...electrode body 44...Spacer tube 45…Flange 46... Ground electrode 47... Joint part 48…Heating channel 49…Media flow path 410…Media supply port 411…Media outlet 50...Temperature sensor 60...Temperature holding part 70…Switching valve 80...1st cooling section 90...First back pressure valve 100... Sterilization filter 110... Pressurized air source 120…Second cooling section 130...Second back pressure valve 140...Filling machine 150...Control Unit 160... Power supply unit 170...First single-screw eccentric pump 180... Second single-screw eccentric pump

Claims

1. A transfer device for transferring fluid food materials, A heating device for heating the aforementioned food material, The heating channel in which the heating device is arranged, A branch channel that branches off from the aforementioned heating channel, A filling channel that communicates with the filling device, A pressurizing device that supplies pressurized air to the aforementioned filling channel, A switching valve having a first position that connects the heating channel and the branch channel, and a second position that connects the heating channel and the filling channel, The system comprises a control unit that controls the operation of the transfer device, the heating device, the switching valve, and the pressurizing device, The filling channel is provided with a cooling section and a filling channel back pressure valve or a single-screw eccentric pump located on the filling device side of the cooling section. The pressurizing device pressurizes the filling passage between the switching valve and the filling passage back pressure valve or the single-screw eccentric pump. The control unit performs a heating start-up step in which it transfers the food material with the switching valve in the first position until the heating device is in stable operation. After the heating device has started operating stably, the switching valve is set to the second position, and the food material is transferred to the filling channel pressurized by the pressurizing device in this preparation step for full operation. The operation step involves stopping the pressurization by the pressurizing device when the food material reaches a predetermined position in the filling channel, A heating apparatus wherein the heating device is a Joule heating device that electrically heats the food material.

2. The heating apparatus according to claim 1, wherein the control unit heats the food material to a temperature higher than 100°C using the heating device in the heating start-up step.

3. Furthermore, the heat treatment apparatus according to claim 1, wherein a sterilization filter is provided between the pressurizing device and the filling channel.

4. Furthermore, the heating apparatus according to claim 1, wherein a filling channel back pressure valve is provided in the filling channel, and the filling channel is pressurized by the pressurizing device supplying pressurized air to the channel between the switching valve and the filling channel back pressure valve.

5. The heating apparatus according to claim 4, wherein the control unit stops pressurizing by the pressurizing device when the food material reaches the back pressure valve of the filling channel during the main operation step.

6. Furthermore, the heating apparatus according to claim 1, wherein a single-screw eccentric pump is provided in the filling passage, and the filling passage is pressurized by the pressurizing device supplying pressurized air to the passage between the switching valve and the single-screw eccentric pump.

7. The heating apparatus according to claim 6, wherein the control unit stops pressurizing by the pressurizing device when the food material reaches the uniaxial eccentric screw pump during the main operation step.

8. The filling channel has a cooling section for cooling the food material heated by the heating device, The heating apparatus according to claim 1, wherein the main operation step involves stopping the pressurization by the pressurizing device when the food material reaches a position beyond the cooling section of the filling channel.

9. A heat treatment method using a heat treatment apparatus according to any one of claims 1 to 8, Until the heating device is in stable operation, the heating start-up step involves transferring the food material with the switching valve in the first position. After the heating device has started operating stably, the switching valve is set to the second position, and the food material is transferred to the filling channel pressurized by the pressurizing device in this preparation step for full operation. A heat treatment method comprising: a main operation step of stopping pressurization by the pressurizing device when the food material reaches a predetermined position in the filling channel; and

10. The heat treatment method according to claim 9, wherein a filling channel back pressure valve is provided in the filling channel, and the filling channel is pressurized by the pressurizing device supplying pressurized air to the channel between the switching valve and the filling channel back pressure valve.

11. The heat treatment method according to claim 9, wherein a single-screw eccentric pump is provided in the filling passage, and the filling passage is pressurized by the pressurizing device supplying pressurized air to the passage between the switching valve and the single-screw eccentric pump.

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