JP7201220B2 - Electric heating device for fluid food material and its control method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric heating device for fluid food materials and a control method thereof.

As one method of heating fluid food materials for sterilization, cooking, etc., the food materials are continuously fluidized and transferred in a pipe, and the electrical resistance of the food materials is used to heat the food. A heating technique (electrical heating, joule heating) that heats the food material itself by directly energizing the material has been put into practical use (for example, Patent Document 1). In this device, the inner surface of the food transport pipeline is concentric with the central axis of the pipeline at least two or more portions at predetermined intervals from the upstream side to the downstream side of the food transport pipeline. An annular electrode body made of a conductive material is provided in the pipe line, and a voltage is applied between the electrode body installed on the upstream side of the pipeline and the electrode body installed on the downstream side, and the fluid food material moving between them It is continuously heated by passing an electric current and generating Joule heat.

In the conventional electric heating apparatus, due to uneven heating caused by non-uniform heating, scaling due to overheating on the inner wall of the flow path has been a problem.
Therefore, the applicant provides cooling medium flow paths in a plurality of electrode bodies, provides a temperature sensor for detecting the inner wall temperature of the heated flow path in the vicinity of the outlet end of the heated flow path, and measures the measured value of the temperature sensor. Based on this, we have proposed a continuous electric heating device that controls the cooling conditions by a liquid cooling medium (Patent Document 2).

Japanese Patent Publication No. 5-33024 Japanese Patent No. 4995164

In a manufacturing line that continuously transfers fluid food materials, when restarting operation after suspending continuous transfer due to a failure or replacement of equipment, the temperature inside the heating channel of the electric heating device has fallen, so the target temperature However, if the automatic energization control is executed in such a case, there is a problem that overshooting and hunting exceeding the allowable temperature occur. In particular, fluid food materials that are denatured by temperature, such as grated yam and eggs, have a problem that if heated above the allowable temperature, the fluid food materials in the pipe will be denatured and must be discarded. be. In addition, with fluid food materials whose viscosity changes with temperature, a drop in the temperature of the electric heating device increases the viscosity of the food material in the pipe, causing defects in the products produced after restarting operation.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a control method for an electric heating device that can stably reach a target temperature in a shorter time than in the past without overshooting or hunting.

The electric heating device of the present invention has a plurality of electrode bodies and a plurality of spacer tubular bodies, the inner walls of which are for electrically heating the food material while flowing and transporting it, and the heating channel or the vicinity of the entrance and exit of the heating channel. and a control device that automatically controls the voltage applied to the electrode body based on a signal from the temperature sensor, wherein the control device comprises performs the automatic energization control after performing a start-up step of performing fixed energization control for applying a constant voltage to the electrode body for a certain period of time when the operation of the energization heating device is started , When restarting the operation of the energization heating device after stopping the operation, the automatic energization control is executed after executing the startup step, and when the operation of the energization heating device is stopped during the automatic energization control. and storing a voltage output value when the operation is stopped, and executing the fixed energization control with the stored voltage output value when the start-up process is executed .
In the electric heating device, when the temperature sensor detects a predetermined temperature lower than a target temperature during the start-up process, the control device switches from the fixed energization control to the automatic energization control. may be
In the energization heating device, the control device may switch from the fixed energization control to the automatic energization control when a predetermined time has elapsed from the start of execution of the start-up process.

A control method for an electric heating device of the present invention includes a heating channel for electrically heating a food material having a plurality of electrode bodies and a plurality of spacer tubes, the inner walls of which are used to flow and transfer food materials, and a heating channel or A control method for an electric heating device comprising: a temperature sensor provided near an entrance thereof; wherein, when the operation of the electric heating device is started, the automatic energization control is executed after performing a start-up step of performing fixed energization control for applying a constant voltage to the electrode body for a certain period of time , When restarting the operation of the energization heating device after stopping the operation, the automatic energization control is executed after the start-up step is executed, and when the operation of the energization heating device is stopped during the automatic energization control. Secondly, the voltage output value at the time of stopping the operation is stored, and the fixed energization control is executed with the stored voltage output value when the start-up process is executed .
In the method for controlling the electric heating device, the fixed electric power control may be performed in a stationary state in which the food material is not transferred, and the automatic electric power control may be performed while the food material is being transferred.
In the method for controlling the electric heating device, the fixed electric power control and the automatic electric power control may be performed while transferring the food material.
In the method for controlling the electric heating device, the food material may be a food material that undergoes irreversible thermal denaturation when it exceeds a certain temperature.
In the method for controlling the electric heating device, the food material may be vegetables including grated yam, fruits including grated apple, jam, dressing, or eggs.

According to the present invention, in a production line that continuously transfers fluid food materials, even when the operation is restarted after the continuous transfer is temporarily stopped, the target temperature is reached in a shorter time than before without overshooting or hunting. stability can be reached.

1 is a configuration diagram of a filling and molding apparatus with a temperature compensation function according to an embodiment; FIG. 1 is an enlarged cross-sectional view of an electric heating device according to an embodiment; FIG. FIG. 4 is a cross-sectional view of a channel of an electrode body according to an embodiment; 6 is a flowchart for explaining temperature control at the time of resuming operation according to the embodiment; 5 is a graph showing an example of temperature change due to temperature control of the electric heating device according to the embodiment. It is a graph which shows an example of the temperature change by the temperature control of the electric heating apparatus based on the conventional embodiment. It is a graph which shows an example of the temperature change by the temperature control of the electric heating apparatus based on the conventional embodiment.

Embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a filling molding apparatus 1 with a temperature compensation function according to an embodiment. This filling and molding apparatus 1 is a group of apparatuses for molding fluid food materials and filling them into bags, and includes a kneader 10, an electric heating device 20, a control unit 30, a power supply unit 40, and a filling and molding machine 50. and In addition, the electric heating device 20 according to the present embodiment can stably reach the target temperature in a shorter time than the conventional electric heating device without overshooting or hunting. , vegetables and fruits such as grated yam and apples that are denatured by heat, food materials such as fruit jams, dressings, and eggs, and food materials such as cheese whose viscosity changes due to heat (melted cheese) Suitable for mold filling.

The kneader 10 has a tank for stirring the fluid food material heated to about 75 to 80° C., and the fluid food material in the kneader 10 is pumped downstream through pipes 11 to 13 by a pump 14. transported quickly. A first opening/closing valve 15 is installed between the pipes 11 and 12 , and a branch flow path having a second opening/closing valve 16 installed in the middle of the pipe 12 is provided. Near the outlet of the pipe 12 (near the inlet of the electric heating device 20), an inlet temperature sensor 31 for measuring the temperature of the central axis of the flow path is provided. ) is provided with an outlet temperature sensor 33 for measuring the temperature of the central axis portion of the flow path. Note that the pipes 11 and 12 may be insulated by double pipes or the like.

An electric heating device 20 is arranged in the middle of the pipes 12 and 13 to heat the temperature of the fluid food material, which has decreased during movement in the pipe 12, before transferring it to the filling machine 50. If the temperature of the fluid food material falls below a certain temperature (for example, 50°C to 60°C or less) immediately before filling, the viscosity of the fluid food material such as melted cheese will increase significantly, causing variations in the filling amount and poor molding. This is because there is a problem that sterilization failure occurs at a temperature below a certain temperature (for example, 60° C. or below) even with other fluid food materials. The electrical heating device 20 electrically heats the fluid food material to a temperature in the range of 60 to 85° C., for example, in consideration of the temperature drop when passing through the pipe 13 .

The filling machine 50 includes a nozzle for filling the bag with the fluid food material and a molding machine for molding the fluid food material filled in the bag. The filling machine 50 also has a hopper, and the fluid food material transferred from the electric heating device 20 is temporarily stored in the hopper. Also, as will be described later, if the filling and molding device 1 breaks down, or if the kneader 10 takes a long time to mix, equipment such as bags for filling fluid food materials and wrapping paper (film rolls) runs out and needs to be replaced. Alternatively, the electrical heating device 20 may be temporarily stopped, such as when the hopper is full of fluid food material. When the electric heating device 20 is temporarily stopped in this way, it may not be possible to heat the fluid food material at an appropriate temperature immediately after the operation is restarted. Poor filling may occur. Therefore, in order to discard such fluid foods, the filling and molding apparatus 1 has a branch valve 17, and by controlling the branch valve 17, the electric heating device 20 stably reaches the target temperature. The fluid food material transferred through the electric heating device 20 can be discarded.

FIG. 2 is an enlarged cross-sectional view of the electrical heating device 20 according to the embodiment. The electric heating device 20 includes a plurality of alternately arranged electrode bodies 23 and a plurality of spacer tube bodies 24, which are clamped and fixed by flanges 22a-22b. The inner diameter of the electrode body 23 and the inner diameter of the spacer tube 24 are the same, and by alternately connecting and communicating with each other, a heating flow path 21 is formed for energizing and heating the food material to be heated.

The electrode body 23 is desirably ring-shaped, but its shape is not particularly limited, such as polygonal or elliptical. The ring-shaped electrode body 23 has an inner surface conforming to the spacer tubes 24, and by alternately arranging the spacer tubes 24, an electrical circuit is formed when the fluid food material passes between the electrodes. Electricity is heated. The electrode body 23 is made of a highly conductive material, and metals such as aluminum, aluminum alloys, titanium, titanium alloys, platinum, pure iron, and stainless steel can be used, for example. Two electrode bodies provided near both ends of the heating channel 21 are ground electrodes 25 for blocking leakage current, and the remaining electrode bodies 23 sandwiched between the ground electrodes 25, 25 are all for electric heating.

The spacer tubular body 24 is made of an insulating material, and is arranged alternately with the electrode bodies 23 to form a conduit that serves as a material flow path to be heated. The spacer tube 24 is made of a non-conductive plastic such as a resin such as polytetrafluoroethylene, polyetheretherketone, polyetherimide, polysulfone. The shape of the spacer tube 24 may be a square cylinder, or a cylinder with a circular inner peripheral surface and a rectangular outer peripheral surface may be used, and the shape is not limited, but the cross-sectional shape of the electrode body 23 It is necessary to make the cross-sectional shape of the spacer tube body 24 correspond to that of the spacer tube body 24 . A sealing material is incorporated between the connecting surfaces of the spacer tubular body 24 and the electrode body 23 to prevent leakage of the material to be heated to the outside of the material flow path 41 to be heated. The length of the spacer tube 24 is the distance between the electrodes, and the ratio (L/R) of the distance L between the electrodes to the inner diameter R of the electrode body 23 (the diameter of the material flow path 41 to be heated) is twice or more. and more preferably 4 times or more and 12 times or less promotes uniform heating.

Joint portions 26 and 26 on the inflow side and the outflow side are provided at both ends of the heating channel 21 . Each of the electrode bodies 23 is connected to the power supply unit 40 so that the electrodes 23, 23 adjacent to each other in the flowing direction of the material to be heated have opposite polarities. The number of electrode bodies 23 provided in the electric heating device 20 can be arbitrarily set according to the heating temperature and the like.

FIG. 3 is a cross-sectional view of the flow path of the electrode body 23. As shown in FIG. A coolant channel 231 is concentrically provided in the electrode body 23 along the inner surface of the heating channel 21 . A cooling medium is supplied from one of the cooling medium supply ports 232 provided in the electrode body and discharged from the cooling medium discharge port 232 provided on the opposite side. The electrode body 23 is further provided with a screw hole 233 for power supply. By providing the cooling medium flow path 231 and circulating the cooling medium, the temperature rise of the electrode body 23 is suppressed and the food on the inner wall surface of the electrode is prevented from being overheated. As the cooling medium, a liquid cooling medium (for example, water) with high cooling performance is used, and the cooling medium flow path is circulated by a known cooling medium supply means (not shown) such as a pump. The technical idea of the present invention can also be applied to an electric heating device including an electrode body that does not have the coolant channel 231 .

In the electric heating device 20 of the embodiment, the electrode temperature sensor 32 is provided only on the ground electrode 25 positioned on the most upstream side. The reason why the temperature sensor is provided at the most upstream portion of the heating channel 21 is that the temperature at the most upstream portion of the heating channel 21 is the lowest and the temperature at the location where the viscosity of the fluid food material is considered to be high can be detected. to obtain. The electrode temperature sensor 32 is preferably provided on the ground electrode 25 positioned on the most upstream side, but may be provided on another electrode body 23 (for example, the electrode body 23 positioned on the most upstream side).

Temperatures measured by the temperature sensors 31 to 33 are sent to the control unit 30 . The control unit 30 includes a processing device, a storage device storing control programs, and an operation panel, and controls the output of the electric heating device 20 based on the measured values of the temperature sensors 31-33. As the temperature sensors 31 to 33, known temperature sensors such as thermocouples can be used. In the embodiment, when the temperature of the inlet temperature sensor 31 is 55°C, the heating is performed so that the temperature of the outlet temperature sensor 33 becomes 75°C.
During normal operation, the power supplied to the electrode body 23 is automatically controlled by PID control based on the measured value of the temperature sensor 33 . The values of the proportional action (P action) and integral action (I action) in PID control are appropriately and optimally set according to the total length of the heating channel 21, the flow velocity of the food material, etc. so as not to cause overshooting or hunting. .

Here, if the filling and molding device 1 breaks down during the filling and molding process of the fluid food material, if it takes time to mix with the kneader 10, the bag or wrapping paper (film roll) filled with the fluid food material It may be necessary to temporarily stop the operation of the filling and molding apparatus 1 when the hopper runs out and needs to be replaced, or when the hopper is full of fluid food materials. The more the temperature of the fluid food material in the channel decreases. For example, it was confirmed that the flowable food material, which was at 75°C, dropped to 55°C when stopped for about 10 minutes. Fluid food materials such as melted cheese become difficult to transfer by the pump 14 when the product temperature drops below 40° C., so it is necessary to discard all the fluid food materials in the flow path.
Even when the temporary stop time is short, the control for adjusting the temperature of the fluid food material whose temperature has decreased is different from that during normal operation. If the same automatic control as during normal operation is performed when the temperature is low, the voltage output value will be higher than during stable operation to warm up to the target temperature, which may cause overshoot or hunting that exceeds the allowable temperature. Moreover, it takes several minutes, for example, to obtain stable operation. In addition, if the heating temperature exceeds the allowable temperature due to overshooting or hunting, fluid food materials such as eggs and grated yam may be denatured. of the flowable food material must be discarded.
Furthermore, the automatic output control by the outlet temperature sensor 33, which is performed during normal operation, is not fed back until the temperature-lowered fluid food material reaches the outlet temperature sensor 33, so there is a problem that a corresponding delay occurs. Fluid food materials transferred until stable operation was obtained had problems of poor quality and poor filling, so it was necessary to discard all of them (for example, at a flow rate of 60 kg / min, several hundred kg flowable food material must be discarded).
Temperature control at the time of resuming operation according to the embodiment will be described below with reference to FIG. 4 . The following description assumes that the temperature of the lowest temperature portion in the flow path is 40° C. or higher.

FIG. 4 is a flowchart illustrating temperature control at the time of resuming operation according to the embodiment.
STEP 101 : When the operation is restarted, the control unit 30 starts the first heating by the electrical heating device 20 . As a result, the fluid food material in the heating channel 21 of the electrical heating device 20 is electrically heated. The first heating is static heating in which the voltage output is constant without automatic control. The voltage applied during static heating may be a preset value, or may be automatically set by storing the voltage value applied when the operation is stopped.

STEP 102-103: Temperature monitoring by the electrode temperature sensor 32 of the heating channel 21 is started. The first heating is continued until the temperature of the electrode temperature sensor 32 reaches the first target temperature (for example, 50°C). The reason why the temperature is monitored by the electrode temperature sensor 32 is that if the cheese near the inner peripheral surface of the heating channel 21 is not sufficiently melted, a so-called hollow (laminar flow) occurs and the inner peripheral surface of the heating channel 21 This is because the cheese in the vicinity may burn. Alternatively, the electrode temperature sensor 32 may not monitor the arrival of the first target temperature, and the first heating may be performed for a predetermined period of time or a period of time corresponding to the suspension period.

STEP104-105: When the temperature of the electrode temperature sensor 32 reaches the first target temperature, the control unit 30 activates the pump 14 to resume transfer of the fluid food material. Also, the sensor to be monitored is switched from the electrode temperature sensor 32 to the inlet temperature sensor 31, and the second heating is started. The second heating is also stationary heating with constant voltage output without automatic control. The first heating and the second heating may be under the same conditions or under different conditions.

STEP 107: Continue the second heating until the temperature of the inlet temperature sensor 31 reaches the second target temperature (for example, 75°C). Here, the second target temperature is the temperature measured by the inlet temperature sensor 31 during normal operation. Alternatively, the second heating may be performed for a predetermined period of time or a period of time corresponding to the temporary stop period without monitoring the arrival of the second target temperature by the inlet temperature sensor 31 .

STEP 108: When the temperature of the inlet temperature sensor 31 reaches the second target temperature (for example, 75° C.), the control unit 30 stops the second heating and automatically controls the output of the electric heating device 20 based on the measured value of the outlet temperature sensor 33. to start. Automatic output control based on the measured value of the outlet temperature sensor 33 is control performed during normal operation.

In the example of FIG. 4, the second heating is performed after the first heating. good. In this case, the first heating may be performed based on the signal from the inlet temperature sensor 31 instead of the signal from the electrode temperature sensor 32 . Alternatively, the second heating may be performed while the fluid food material is transferred by activating the pump 14 without performing the first heating. That is, when the operation is restarted, the fixed energization control may be performed while transferring the fluid food material. In this case, it is preferable to control the branch valve 17 and discard the food material in the flow path.
Further, the static heating performed in the first heating may be performed with different output depending on the temperature value detected by the electrode temperature sensor 32 or the inlet temperature sensor 31 . The relationship between the time required to reach the target temperature from a certain temperature and the voltage value should be calculated by experiments in advance and described in the control program.

Next, the effect of temperature control of the electric heating device 20 according to the embodiment will be described. FIG. 5 is a graph showing an example of temperature change due to temperature control of the electric heating device 20 according to the embodiment, and FIGS. 6 and 7 show temperature changes due to temperature control of the electric heating device according to the conventional embodiment. It is a graph which shows an example of. 5 to 7, heating was started at 27.degree. C. with the target temperature of the outlet temperature sensor 33 being 60.degree. The voltage output value was 280V when the target temperature of 60°C was maintained. Furthermore, the amount of treated saline solution was set to 180 L per hour, and the heating time was set to 20 seconds. Then, in the examples shown in FIGS. 5 to 7, the time from the start of voltage application until the temperature measured by the outlet temperature sensor 33 stabilizes at the target temperature of 60° C.±1° C. was measured. In addition, "the time until the target temperature is stabilized at 60°C ± 1°C" is the time until the initial temperature reaches 59°C when the time from 59°C to 61°C continues for several seconds (for example, 5 seconds). It was measured. In addition, the time required for the applied voltage to stabilize at 280 V was also measured.

The graph shown in FIG. 5 shows a case where temperature control is performed by the electric heating device 20 according to the embodiment. C., and automatic energization control was performed after the temperature measured by the outlet temperature sensor 33 reached 50.degree. In this case, as shown in FIG. 5, it took 38 seconds from the start of voltage application until the temperature stabilized at the target temperature of 60° C.±1° C. on the outlet side of the saline solution. Further, it took 5 seconds from the start of voltage application until the applied voltage was stabilized at 280V. As shown in FIG. 5, in the energization heating device 20 according to the embodiment, fixed energization control is performed until a predetermined temperature of 50°C, which is lower than the target temperature of 60°C, is reached, and the temperature measured by the outlet temperature sensor 33 reaches 50°C. After that, by performing automatic energization control, it was possible to prevent overshoot and hunting. As a result, it was found that, when handling fluid food materials such as eggs and grated yam, denaturation of these fluid food materials due to heat can be effectively prevented.

On the other hand, the graph shown in FIG. 6 shows an example of temperature change when temperature control (automatic energization control (PID control) from the beginning of operation restart) of the energization heating device according to the conventional embodiment is executed. In this case, it took 106 seconds from the start of voltage application until the temperature measured by the outlet temperature sensor 33 stabilized at the target temperature of 60°C ± 1°C. Further, it took 90 seconds from the start of voltage application until the applied voltage was stabilized at 280V. This is because, in the example shown in FIG. 6, the voltage output value is suppressed at an earlier timing than in the example shown in FIG. It is possible that it was delayed.

In the graph shown in FIG. 7, as shown in FIG. 6, it is an example of executing temperature control (automatic energization control (PID control) from the beginning of operation restart) of the energization heating device according to the conventional embodiment. In the example shown in FIG. 7, since it takes time to raise the output voltage value in the example shown in FIG. 6, the proportional gain of PID control is set so as to raise the output voltage value in a short time. In this case, as shown in FIG. 7, it took 222 seconds for the temperature measured by the outlet temperature sensor 33 to stabilize at the target temperature of 60° C.±1° C. from the start of voltage application. Further, it took 320 seconds from the start of voltage application until the applied voltage was stabilized at 280V. Furthermore, in the example shown in FIG. 7, since the output voltage value was raised in a short period of time, overshoot and hunting occurred, and it took extra time to stabilize at the target temperature.

As described above, the electric heating device 20 of the embodiment shown in FIG. 6 and 7, the output voltage value can be increased in a short time, and overshoot and vibration phenomena (hunting) can be prevented compared to the case where automatic energization control (PID control) is executed from the beginning of operation restart shown in FIGS. It turns out that it can be prevented.

In the example shown in FIG. 5 described above, the configuration is illustrated in which the fixed energization control is switched to the automatic energization control on the condition that the temperature measured by the outlet temperature sensor 33 is 10° C. lower than the target temperature. However, without being limited to this configuration, for example, it is possible to switch from fixed energization control to automatic energization control on the condition that the temperature measured by the outlet temperature sensor 33 is 5 to 15° C. lower than the target temperature. can. Also, the temperature can be appropriately changed according to the type and properties of the fluid food material. Further, as a condition for switching from fixed energization control to automatic energization control, it is possible to set a predetermined period of time after the start of voltage application. Also in this case, the predetermined time can be appropriately set according to the type and properties of the fluid food material, and can be set to 20 to 30 seconds, for example.

According to the filling and molding apparatus 1 with temperature compensation function according to the embodiment described above, since the temperature of the fluid food material can be raised in a short time by the electric heating device 20, the heat between the pipes 12 and 13 can be increased. It is possible to shorten the length of the pipes 12 and 13 as compared with the configuration in which the exchanger is installed. In addition, in the case of a structure in which the pipes 12 and 13 are kept warm by double pipes, etc., the food material in the pipes continues to be heated even during a temporary stop, and product deterioration occurs. Heating is also stopped, so there is no problem of product deterioration.

A plurality of electric heating devices 20 may be connected in series. In this case, the inlet temperature sensor 31 is installed near the entrance of the electric heating device 20 positioned most upstream, and the electrode temperature sensor 32 is positioned most upstream. The outlet temperature sensor 33 is installed near the exit of the electrical heating device 20 located most downstream.
The filling and molding apparatus 1 with a temperature compensation function according to the embodiment is not limited to application to fluid food materials, but any fluid food whose viscosity increases due to a decrease in temperature (e.g., custard cream, creme, sauce, jams, fruit sauces). Liquid seasoning liquids containing thickeners can also be used as fluid foods whose viscosity changes with a decrease in temperature. A drop in temperature immediately before filling fluid food not only causes a decrease in the filling amount, but also may cause a sealing failure problem due to insufficient heat quantity of the bag product, but the present invention also solves such problems. It is possible. It is also useful for heat-denatured fluid food materials such as eggs and grated Japanese yam, since overshooting and vibration phenomena (hunting) can be prevented.

1 Filling and molding device with temperature compensation function 10 Kneader 11 to 13 Pipe 14 Pump 15 First opening and closing valve 16 Second opening and closing valve 17 Branch valve 20 Electric heating device (Joule heating device)
21 heating channel 22 flange 23 electrode body (ring-shaped electrode)
24 spacer 25 ground electrode (ring-shaped electrode)
26 joint part
30 control unit (control device)
31 inlet temperature sensor 32 electrode temperature sensor 33 outlet temperature sensor 40 power supply unit

Claims (8)

having a plurality of electrode bodies and a plurality of spacer tubes;
a heating channel for electrically heating the food material while their inner walls flow and transfer the food material;
a temperature sensor provided near the heating channel or its entrance;
and a control device that automatically controls the voltage applied to the electrode body based on a signal from the temperature sensor, the energization heating device comprising:
The control device is
When the operation of the energization heating device is started, after performing a start-up step of performing fixed energization control for applying a constant voltage to the electrode body for a certain period of time, the automatic energization control is performed ,
When restarting the operation of the energization heating device after stopping the operation, the automatic energization control is executed after the start-up step is executed, and when the operation of the energization heating device is stopped during the automatic energization control. (2) an electric heating apparatus , wherein a voltage output value when the operation is stopped is stored, and the fixed energization control is executed with the stored voltage output value when the start-up process is executed ; 2. The apparatus according to claim 1 , wherein the control device switches from the fixed energization control to the automatic energization control when the temperature sensor detects a predetermined temperature lower than a target temperature during execution of the start-up process. The electrical heating device described. 2. The energization heating device according to claim 1 , wherein the control device switches from the fixed energization control to the automatic energization control when a predetermined time has elapsed from the start of execution of the start-up process. having a plurality of electrode bodies and a plurality of spacer tubes;
a heating channel for electrically heating the food material while their inner walls flow and transfer the food material;
a temperature sensor provided near the heating channel or its entrance;
a control device for automatically controlling voltage applied to the electrode body based on a signal from the temperature sensor, the control method for an electric heating device comprising:
When the operation of the energization heating device is started, after performing a start-up step of performing fixed energization control for applying a constant voltage to the electrode body for a certain period of time, the automatic energization control is performed ,
When restarting the operation of the energization heating device after stopping the operation, the automatic energization control is executed after the start-up step is executed, and when the operation of the energization heating device is stopped during the automatic energization control. (2) a control method for an electric heating device, characterized in that a voltage output value when the operation is stopped is stored, and the fixed energization control is executed with the stored voltage output value when executing the start-up process ; executing the fixed energization control in a stationary state in which the food material is not transferred;
5. The method of controlling an electric heating device according to claim 4 , wherein the automatic electric power control is executed while transferring the food material. 5. The method of controlling an electric heating device according to claim 4 , wherein said fixed energization control and said automatic energization control are executed while transferring said food material. 7. A control method for an electric heating device according to claim 4 , wherein said food material is a food material that undergoes irreversible thermal denaturation when it exceeds a certain temperature. 8. The method of controlling an electric heating device according to claim 7 , wherein the food material is vegetables including grated yam, fruits including grated apple, jam, dressing, or eggs.

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