JP4995164B2 - COOLABLE ELECTRODE BODY AND CONTINUOUS ELECTRIC HEATING DEVICE HAVING THE SAME - Google Patents

Description

  The present invention relates to a coolable electrode body and a continuous energization heating apparatus including the same, and more particularly to an electrode body including a cooling medium flow path and a built-in temperature sensor and an energization heating apparatus including the same. . The continuous energization heating device of the present invention allows a current to be uniformly passed through a material to be heated, and enables appropriate heat treatment according to the characteristics of the material to be heated, particularly food material. The present invention provides a heating means useful in the heating technical field, particularly in the food processing field.

  As one of the methods of heating fluid food materials for sterilization, cooking, etc., the food material is continuously fluidized and transferred in the pipe, and the food material is used for the electric resistance. A heating technique (electric heating, Joule heating) that generates heat by directly energizing the material has been put into practical use (for example, Patent Document 1). In this apparatus, the inner surface of the pipeline is arranged so as to be concentric with respect to the central axis of the pipeline at at least two portions at a predetermined interval from the upstream side to the downstream side of the food transport pipeline. An annular electrode body made of a conductive material is provided, and a voltage is applied between the electrode body installed on the upstream side of the conduit and the electrode body installed on the downstream side in the fluid food material that moves between them. It is heated continuously by passing an electric current and generating Joule heat.

  However, such a type of heating apparatus has room for improvement in terms of uniform heating. That is, when the fluid food material flowing in the pipe is heated, there is a problem that the heating is nonuniform in the portion near the central axis position of the pipe and the portion near the inner peripheral surface of the pipe. In general, when current flows through a medium, if the specific resistance of the medium is uniform, the current normally flows through a path with the smallest electrical resistance, that is, the shortest distance. Therefore, if a voltage for current heating is applied between the annular electrode body on the upstream side and the annular electrode body on the downstream side in a state where the flowable food material is allowed to flow in the pipeline, the current will flow within the pipeline. It shows the tendency to flow through the part near the circumference. As a result, the current density increases near the inner surface of the pipeline through which the food material flows, while the current density decreases extremely near the central axis of the pipeline, resulting in food near the inner periphery of the pipeline. While the material is likely to be overheated, the food material is less likely to be heated near the central axis.

  Such a problem that it is difficult to heat the food material uniformly becomes particularly prominent when heating food materials with high viscosity such as mayonnaise, liquid egg, fruit sauce, jam and the like. The cause is derived from the viscous resistance between the inner surface of the pipeline and the flowable food material in addition to the non-uniform flow of current to the food material in the pipeline. In particular, in the case of fluid food materials with high viscosity, the flow velocity becomes extremely small near the inner surface of the pipeline compared to the central axis position due to the viscous resistance between the inner surface of the pipeline and the food material. In the vicinity of the inner surface, the flow time of the current in the fluid food material becomes extremely long, and overheating is more likely to occur near the inner surface of the pipe.

  In addition, in current heating, a flowable food material generally tends to cause a current to flow as its temperature rises, so that the current concentrates more on the food material that has been overheated and heated near the inner peripheral surface of the pipeline. As a result, the food material flowing near the inner peripheral surface of the pipe line has a problem that the temperature rises rapidly and the temperature difference from the food material flowing near the central portion becomes large. In this way, if the food material is overheated, even if sterilization can be performed sufficiently, the food texture and flavor of the food may be impaired, discoloration may occur, and nutritional components may be destroyed, In order to obtain food of excellent quality, it is necessary to avoid overheating.

  Furthermore, if the fluid food material that flows near the inner peripheral surface of the pipeline is overheated, scaling problems often occur where the food material becomes solidified by heat denaturation or adheres to the inner surface of the pipeline due to scorching. To do. In that case, not only the flavor of the food material is impaired, but also a large current locally flows or sparks due to carbonization of the fixed part, and the spacer tube is locally melted or damaged. Or the energized state may become unstable and appropriate temperature control may be difficult. In particular, the flowable food material containing a large amount of protein such as mayonnaise, liquid egg, or soy milk tends to be denatured and solidified by overheating, and this phenomenon becomes remarkable. Therefore, prevention of sticking of the food material to the inner surface of the pipe line is recognized as an important problem to be solved.

  Conventionally, many techniques for preventing overheating of the inner surface of the food transport pipe have been proposed. For example, a pair of electrodes that are curved along the circumference of the pipe line and are opposed to each other in the diameter direction of the pipe line are used as counter electrode bodies, and a plurality of sets of counter electrode bodies are sequentially spaced apart in the length direction of the pipe line. The configuration is such that the installation angle is shifted, and by applying a voltage between a pair of electrodes constituting each counter electrode, the flowable food material flowing in the pipe line passes between the electrodes of the plurality of counter electrode bodies. There has been proposed a continuous energization heating device that can be heated uniformly to a high temperature without overheating the fluid food material as a whole and passing over, or conversely, insufficient heating. (See Patent Document 2).

Moreover, by providing a stirring means for stirring the food material flowing in the pipe line in the transverse direction of the pipe line between the electrodes for electric heating, the flowable food can be moved in the pipe line by the electric heating. In the continuous heating, a heating device that uniformly heats the entire food material without causing local overheating or insufficient heating has been proposed (see Patent Document 3). Furthermore, in a continuous energization heating device that continuously energizes and heats the flowable food material by applying a voltage between the ring electrode bodies, the flow direction of the flowable food material changes in a stationary state on the inner part of the ring electrode body. A static stirrer that applies stirring force to the flowable food material and energizes between the two annular electrode bodies by applying the same potential between the two annular electrode bodies on both sides of the static stirrer. There has been proposed an energization heating device that is heated to prevent overheating and improve the durability of a static stirring body (see Patent Document 4).
However, in these apparatuses, the installation of a large number of electrodes having a complicated structure in the flow path or the provision of a static stirrer makes the apparatus more complicated. A lot of labor was required for maintenance, management and cleaning during operation.

Therefore, the applicant has a cylindrical body formed with an inner peripheral surface for guiding a fluid food material and an inner peripheral surface corresponding to the inner peripheral surface, and is provided at both end openings of the cylindrical body. A heating member is formed with the annular electrode, and a hollow portion is formed in the electrode to flow a refrigerant for preventing the food material from being heated by conduction heat from the electrode. We proposed a Joule heating unit for food materials with fluidity.
Japanese Patent Publication No. 5-33024 JP 2001-169914 A JP 11-89522 A JP 2003-339537 A Japanese Patent No. 2659313

  With regard to uniform heating in the pipe in the conventional energization heating apparatus, scaling due to overheating on the inner wall of the flow path due to temperature unevenness becomes a problem. In particular, in energization heating of food material containing protein, since the protein is thermally denatured when the food material exceeds a specific temperature, scaling is likely to occur. Scaling causes overheating, and there are problems such as deterioration of the quality of food materials and occurrence of sparks due to mixing of scale. Even if the stirring means is provided in the heating flow path, there still remains a problem that scaling occurs in the stirring means itself. In addition, it is possible to prevent scale growth by periodically cleaning the heating channel at a short timing, but it is difficult to grasp the appropriate cleaning time, and production by increasing the frequency of cleaning A new problem of degradation occurs.

  In the joule heating device described in Patent Document 5, it is possible to circulate a refrigerant for cooling the electrode body. However, it is difficult to accurately measure the temperature of the inner wall portion of the heated channel including the electrode body, and there is room for improvement in terms of performing appropriate temperature control in accordance with the characteristics of foods.

By the way, in the conventional Joule heating device, the temperature is controlled for each power supply unit, and the installation position of the temperature sensor is also provided in the flow path on the downstream side of the heating device. That is, even if heating temperature unevenness occurs between the upstream heating unit and the downstream heating unit, temperature control for eliminating the heating temperature unevenness may not be performed appropriately.
Moreover, conventionally, the temperature sensor provided in the vicinity of the outlet end of the heating unit is for measuring the central axis portion of the flow path, and is not for measuring the inner wall portion of the flow path. This is because in the case of a food material in which laminar flow occurs, the temperature becomes the lowest due to the highest speed of the central axis portion of the flow path. In other words, the temperature sensor at the outlet end is intended to grasp the minimum temperature for performing heat treatment such as sterilization, and predicts the temperature of the inner peripheral wall surface of the pipe line based on this measured value. Was difficult.

The inventor initially studied to embed a temperature sensor in the electrode body and to cool the electrode body from the outside with a liquid cooling medium such as water. However, when the temperature rise of the inner wall of the electrode body becomes a problem, in the configuration in which the electrode body is cooled from the outside, the inner wall must be cooled by heat conduction from the outside, so the cooling capacity is low, and the electrode It was difficult to control the temperature of the inner wall of the body within a desired range.
In such a situation, in view of the above prior art, the present inventors have made intensive efforts with the goal of developing a continuous current heating apparatus in which the material to be heated is not overheated. In a continuous energization heating apparatus including an electrode body in which a cooling medium flow path is formed, it is possible to accurately measure the maximum temperature of the inner wall of the heated flow path, thereby cooling the electrode body by the cooling medium flow path. It has become possible to control under better conditions than before.

  An object of the present invention is to provide a coolable energization heating electrode body and a continuous energization heating apparatus including the same that can solve the above-described problems of the prior art.

The present invention for solving the above-described problems comprises the following technical means.
The continuous energization heating device of the present invention is an energization heating electrode body whose inner wall forms a heating flow path, and the cooling medium flow path is within a range closer to the heating flow path than half of the thickness (T) of the electrode body. The electrode body provided with is provided. In this electrode body, the cooling medium flow path provided in the electrode body is separated from the heating flow path by a wall (438) having a thickness in the range of 5% to 25% of the thickness (T) of the electrode body. Preferably it is. More preferably, the cross section of the cooling medium flow path has an annular shape concentric with the central axis of the heating flow path. Moreover, it is good also as a structure which provides the hole for inserting an electrode temperature sensor, the hole for power supply connection, a cooling-medium supply hole, and a cooling-medium discharge hole toward the heating flow path from the outer surface.

In operating the continuous energization heating device of the present invention, it is important to manage the temperature of the material to be heated, but it is necessary to provide a temperature sensor in the vicinity of the outlet end of the heated channel in order to perform appropriate temperature management. is there. For example, when supplying different voltages between electrode bodies and heating them, an electrode temperature sensor is provided at least on the most downstream electrode body for each group of electrode bodies that use the same voltage, that is, the most downstream that becomes a voltage change point. It is disclosed that an electrode temperature sensor is provided on the electrode body.
The heating device of the present invention has 10 ² mPa.s. A material having a viscosity equal to or greater than s or a material to be heated that is susceptible to thermal denaturation is preferred. As a cooling medium, water can be given as a most preferable example in consideration of hygiene, cooling capacity, economy, and the like.

The electrode body of the present invention has a characteristic in its structure, and in the electrode body for energization heating having a heating channel through which the material to be heated flows, the thickness (T) is provided inside the electrode body. The cooling medium flow path is provided in a range closer to the heating flow path than half of the above, and the liquid cooling medium can be circulated through the cooling medium flow path by the cooling medium feeding means. Further, heat is efficiently transferred by separating the cooling medium flow path from the heating flow path by a wall having a thickness in the range of 5% to 25% of the thickness (T) of the electrode body. Then, by making the cross section of the cooling medium flow path concentric with the heating flow path, the entire inner wall constituting the heated flow path can be uniformly cooled.
In the electrode body of the present invention having such characteristics, the flow rate of the refrigerant flowing through the electrode body can be reduced as compared with the conventional case, so that the cooling medium flow path can be narrowed. In the electrode body having such a cooling medium flow path, since the hole can be provided from the side surface toward the heated flow path, the temperature sensor can be inserted from the outer peripheral surface toward the center. . Similarly, a power connection hole, a cooling medium supply hole, and a cooling medium discharge hole can be provided in the main body of the electrode body. For this reason, processing is easy, and durability and maintainability are also good.

The continuous energization heating device of the present invention is provided with a temperature sensor for detecting the inner wall temperature of the heated channel near the outlet end of the heated channel, preferably near the downstream side of the electrode member for heating and heating which is the highest temperature. And the cooling condition by the liquid cooling medium is controlled based on the measured value of the temperature sensor. As an arrangement mode of the temperature sensor, for example, (A) it is embedded in the electrode body arranged on the most downstream side of the heating unit, and (B) has a flow channel communicating with the heated flow channel, and the most downstream of the heating unit. It is disclosed that a joint member (which may be a flange-combining member) is provided, and the temperature sensor is disposed on the inner wall portion of the flow path.
In the embodiment (A), it is most preferable to provide a temperature sensor on the electrode body for grounding. This is because the temperature of the cooling medium is not affected as compared with the case where the temperature sensor is provided in the electrode body provided with the cooling medium flow path. However, in the case of adopting a configuration in which no grounding electrode body is provided, the cooling medium flow path and the temperature sensor can be provided in one electrode body (see FIGS. 3 and 4).
In the aspect of (B), it is important to provide a temperature sensor so that the temperature of the inner wall portion of the flow path formed at the joint can be measured pinpoint. This is because, generally, the temperature of the inner wall portion tends to be higher than that of the central axis portion of the flow path. This tendency is further promoted particularly in a fluid food material having a viscosity in which laminar flow occurs. In addition, since there is a problem of cracking and a problem of cleaning properties, avoid providing a temperature sensor in the spacer.
In addition to the above configuration, a temperature sensor embedded in an electrode body disposed in the uppermost stream of the heating unit may be provided.

The present invention is applied mainly when thermal denaturation due to laminar flow occurs, but there is a correlation between the material to be heated and the viscosity thereof, which are likely to undergo thermal denaturation due to laminar flow. For example, food materials can be classified into the following three groups according to viscosity, but the present invention is particularly suitable for materials having a viscosity of the second group (medium viscosity) or higher. However, the present invention is suitable for the first group (low viscosity) that is extremely susceptible to heat denaturation, such as soy milk, eggs, and protein-containing substances.
(First group (low viscosity, less than 10 ² mPa · s))
Beverages (Japanese tea, fruit juice, soy milk, tomato juice, etc.), sauces / tsuyu (pickled soup, noodle soup, etc.), low-viscosity dressings (soy sauce base, non-oil type, etc.), soups (consomme soup, extract, etc.), Whole egg liquid egg (second group (medium viscosity, 10 ² to 10 ⁵ mPa · s))
Sauces (medium sauce, fruit sauce, pasta sauce, mayonnaise, etc.), viscous soups (corn soup, curry paste, etc.), viscous sauces / tsuyu (boiled sauce, sesame sauce, etc.), viscous dressings (sesame, Southern islands, etc.), cheeses, salted egg (third group (high viscosity, over 10 ⁵ mPa · s))
Seaweeds (mekabu, mozuku, etc.), red bean paste, miso, salads (potato salad, etc.), sandwich ingredients (eg egg filling), flower pastes

The following effects are exhibited by the present invention.
(1) By efficiently cooling the electrode body and appropriately controlling the temperature, stable heating can be achieved at the optimum temperature for the intended heat treatment, and the deterioration of the quality of the food material that is the object to be heated is suppressed. can do.
(2) Since heated materials such as food materials that come into contact with the electrode body do not adhere as scales to the inner wall (wall surface of the electrode body) of the heating channel, generation of sparks during energization heating and instability of the energization state Can be prevented.
(3) Deterioration of electrode bodies and spacers due to occurrence of sparks can be prevented.
(4) It is possible to solve the problem of overheating that causes thermal denaturation such as the loss of flavor, fragrance and nutritional components of food materials.

Hereinafter, an example of the best mode of the present invention will be specifically described.
The best mode of the present invention includes an electrode body and an insulating spacer, and alternately connects and communicates the electrode body and the spacer to form a heating channel through which a material to be heated continuously circulates. A continuous energization heating apparatus including a Joule heating apparatus that includes a plurality of heating units and supplies power between electrode bodies while supplying a material to be heated in a heating flow path to electrically heat the material to be heated. The electrode body for use is provided with a cooling medium flow path, and the electrode body for grounding is provided with an electrode temperature sensor. More preferably, a cooling medium feeding means capable of adjusting the flow rate of the liquid refrigerant is provided according to the measurement value of the electrode temperature sensor.

  The overall configuration of the continuous energization heating device includes, for example, a joule heating device composed of a plurality of heating units, an agitation cooler connected downstream thereof, a temperature measurement device, a control unit, a power supply unit, and an operation panel as main components. To do. The heating unit is composed of a plurality of electrode bodies and a plurality of spacers arranged alternately, and a heating flow path through which the material to be heated continuously flows is formed. The electrode body and the spacer are fixed by a plate, a flange, and a tie rod. The hollow part of the electrode body and the inner peripheral diameter of the spacer are the same diameter, and a heating flow path is formed through which food materials and the like can smoothly flow.

  Of the plurality of heating units, the upstream side may be a preheating unit, and the downstream side may be a heating unit. In this case, normally, a high voltage is applied to the preheating portion and a low voltage is applied to the heating portion to control the amount of heat generation and heating is performed. The electrode bodies in a single heating unit may be used separately for preheating and heating. In particular, the electrode unit having the cooling medium flow path of the present invention is used for a heating unit that is at a high temperature. However, the number of electrode bodies to be cooled and the positions of the electrode bodies are appropriately determined according to heating conditions. The For example, when preheating and heating are performed using one heating unit shown in FIG. 2, the electrode body having the cooling medium flow path of the present invention is disposed in the second to ninth electrode bodies from the upstream. preferable. When a plurality of heating units are used, all of the heating units can be used as the electrode body having the cooling medium flow path of the present invention.

  The preferred temperature rise per heating unit is generally 10-15 ° C. This is because the temperature difference (ΔT) between the central axis portion and the inner peripheral surface portion of the channel to be heated increases as the temperature rise width increases. One reason for this is that when the temperature increase width is increased by a certain level or more, the electrode body is further heated as the amount of supplied power increases. However, in an electrode body having a cooling medium flow path for circulating a coolant, like the electrode body of the present invention, the temperature rise width can be set relatively high compared to an electrode body that does not have a cooling medium flow path. It is. Further, in the present invention, as described below, since the amount of power supplied is controlled for each heating unit, it is possible to minimize the increase in temperature difference (ΔT) even when the temperature increase range is increased. Is possible.

FIG. 8 is a flowchart showing an example of an energization control procedure based on the measured temperature for each heating unit of the present invention. Hereinafter, temperature detection for each heating unit will be described based on the detection temperature of the electrode temperature sensor on the assumption that a laminar flow occurs. The reference numerals are based on the examples of FIGS.
The temperature of the electrode temperature sensor 5 is detected by the temperature measuring device 105 (step S1), the time at the time of temperature detection is stored, and the measurement information is transmitted to the control unit 54 (step S2). Subsequently, the control unit 54 determines whether or not the detected temperature is equal to or higher than a reference value (step S3). If the detected temperature is equal to or lower than a preset reference value, the process returns to step S1 again.
In step S3, if the detected temperature is equal to or higher than the reference value, it is determined whether or not the detected temperature is lower than the dangerous value (step S4). If the detected temperature is lower than the dangerous value, a cleaning alarm is issued ( Step S5). This is because it is assumed that overheating partially occurs due to the occurrence of scaling and the like, so that the temperature of the electrode body 43 is likely to rise.
In step S4, when the detected temperature is equal to or higher than the dangerous value, the power supply unit 56 is turned off (step S6). This is because it is assumed that scaling is in a growth state.

FIG. 9 is a flowchart showing an example of an energization control procedure based on the temperature difference between the outlet temperature sensor 4 and the electrode temperature sensor 5 of the present invention.
The temperature of the outlet temperature sensor 4 is detected by the temperature measuring device 104, the temperature of the electrode temperature sensor 5 is detected by the temperature measuring device 105 (step S11), the time at the time of temperature detection is stored, and the measurement information is stored in the control unit 54. Is transmitted (step S12). Subsequently, in the control unit 54, it is determined whether or not the temperature difference between the outlet temperature sensor 4 and the electrode temperature sensor 5 is greater than or equal to a reference value (step S13). If the temperature difference is less than or equal to a preset reference value, the process returns to step S11 again.
In step S13, if the temperature difference is greater than or equal to the reference value, it is determined whether or not the detected temperature is less than the dangerous value (step S14). If the detected temperature is less than the dangerous value, a cleaning alarm is issued ( Step S15). This is because it is assumed that overheating partially occurs due to the occurrence of scaling and the like, so that the temperature of the electrode body 43 is likely to rise.
In step S14, when the detected temperature is equal to or higher than the dangerous value, the power supply unit 56 is turned off (step S16). This is because scaling grows and risks such as sparks are assumed.
By performing the energization control as described above, it is possible to prevent the occurrence of scaling and to avoid the problem of cracks caused by the occurrence of scaling. 8 and 9, the control method for turning off the power supply unit 56 has been described. However, the voltage may be reduced, and in a production line including a storage tank or the like after Joule heating, power control and In addition, the flow rate may be controlled.

Next, an example of the best mode for carrying out the present invention will be described in more detail with reference to FIGS.
FIG. 1 is a diagram showing an example of the overall configuration of an energization heating device of the present invention using a Joule heating device 13 provided with an electrode body having a cooling medium flow path. The energization heating apparatus of the present invention mainly includes a Joule heating apparatus 13 including a heating unit 8, an agitation cooler 12 connected downstream thereof, temperature measuring instruments 104 and 105, a control unit 54, a power supply unit 56, and an operation panel 55. It is a component. The heating unit 8 includes a plurality of electrode bodies 43 and a plurality of spacer tube bodies 44 arranged alternately, and is fixed by the plate 6 and the flanges 7a to 7d. The inner diameter of the electrode body 43 and the inner diameter of the spacer tube body 44 are the same, and a flow path for a material to be heated that heats and heats food material and the like is formed by alternately connecting and communicating with each other.

  The electrode body 43 is preferably ring-shaped, but there is no particular limitation on its shape such as a polygon or an ellipse. The ring-shaped electrode 43 has an inner surface shape that coincides with the spacer tube 44, and by alternately arranging the spacer tubes 44, an electrical circuit is formed and energized and heated when food passes between the electrodes. (See FIG. 2). The electrode body 43 is made of a highly conductive material. For example, aluminum, an aluminum alloy, titanium, a titanium alloy, or a metal such as platinum or pure iron can be used. From the viewpoint of corrosion resistance, titanium, titanium, and the like. It is preferable to use an alloy or platinum. Of the electrode bodies 43 in the heating unit 8, the electrode bodies 43 at both ends are ground electrodes for preventing leakage current, and the remaining electrode bodies 43 are current-carrying heating electrodes.

  The spacer tube body 44 is made of an insulating material, and is arranged alternately with the electrode body 43 to constitute a tube path that becomes a heated material flow path. The spacer tube 44 is made of a non-conductive plastic, for example, a resin such as polytetrafluoroethylene, polyetheretherketone, polyetherimide, or polysulfone. The shape of the spacer tube 44 may be a rectangular tube, or a tube having a circular inner peripheral surface and a rectangular outer peripheral surface may be used. It is necessary to make the cross-sectional shapes of the spacer tube body 44 correspond to each other. A sealing material is incorporated between the connection surfaces of the spacer tube body 44 and the electrode body 43 to prevent the heated object from leaking outside the heated material flow path 41. The length of the spacer tube 44 is the distance between the electrodes. The distance L between the electrodes is such that the ratio (L / R) to the inner diameter R of the electrode body 43 (the diameter of the heated material channel 41) is twice or more. Preferably, uniform heating is promoted by being 4 times or more and 12 times or less.

  FIG. 2 is an enlarged cross-sectional view of the heating unit 8 constituting the joule heating device 13. The heating unit 8 has a current-carrying heating section 42 having a circular cross section in which a heating channel 41 for guiding food material is formed. As described above, the energization heating unit 42 includes a plurality of ring-shaped electrode bodies 43 and a plurality of spacer tube bodies 44 disposed therebetween. As shown in FIG. 2, joint portions 45 and 46 on the inflow side and the outflow side are provided at both ends of the energization heating unit 42. Each electrode body 43 is connected to the power supply unit 56 so that the electrode bodies 43 adjacent to each other in the direction in which the material to be heated flows have opposite polarities. The number of electrode bodies 43 provided in the heating unit 8 is a design matter that is arbitrarily set according to the heating temperature and the like. For example, among the electrode bodies 43, 43... In FIG. 2, the cooling medium flow path for cooling is provided in the second to ninth electrode bodies from the upstream.

  The heating channel 41 is installed with an inclination, and the standard setting is such that the amount of a material to be heated such as food material is fed from the bottom to the top. This is because if there is a space in the heating flow path 41, there may be a problem that the electric energy applied to the food is not uniform because the energization between the electrode bodies is hindered. In addition, when there is no problem of air accumulation due to the falling, it may be installed in parallel, for example.

  The heating unit 8 includes an outlet temperature sensor 4 provided at the outlet portion of the heating channel 41 and at least one electrode temperature sensor 5. By providing a temperature sensor, which has been conventionally provided for each power supply unit, for each heating unit and for each electrode body, it is possible to measure the precise temperature at each position within the heating unit. However, the present invention is particularly advantageous when the electrode temperature sensor 5 is provided on a specific electrode and there are a plurality of heating units, for example, when the number of heating units is three or more. Scaling in the flow path is likely to occur when the food material reaches a certain temperature or higher. Therefore, in a configuration composed of a plurality of heating units, scaling is usually likely to occur at the final stage where the temperature is highest. However, when using a food material that easily undergoes thermal denaturation, scaling may also occur in heating units other than the final stage, and therefore it is preferable to provide a temperature sensor at least on the most downstream electrode body.

  When the sensor can be provided only in either the outlet temperature sensor 4 or the electrode temperature sensor 5, the electrode temperature sensor 5 is provided. This is because the temperature of the electrode body 43 is higher than that of the outlet portion. By providing the electrode temperature sensor 5 on the electrode body 43 constituting the inner peripheral surface of the pipe line, the outer peripheral surface of the heating channel 41 (the current heating unit 42). It is possible to capture the temperature of the inner peripheral surface. As the outlet temperature sensor 4 and the electrode temperature sensor 5, a known temperature sensor such as a thermocouple can be used.

  The heating unit 8 can monitor whether the temperature difference between the outlet temperature sensor 4 and the electrode temperature sensor 5 is equal to or greater than a predetermined value. In the case of a non-Newtonian fluid (for example, mayonnaise, liquid egg, fruit sauce, jam, etc.) in which a so-called laminar flow occurs, it is considered that the temperature of the inner peripheral surface of the heating channel 41 is higher than the vicinity of the central axis. It is a configuration. When the temperature rise per one heating unit 8 is large, for example, when it exceeds 10 ° C., more specifically when it exceeds 15 ° C., a particularly advantageous effect is obtained. Further, the heating state can be determined by comparing the temperatures of the heating units 8. In the heating unit 8 in which the temperature difference between the outlet temperature sensor 4 and the electrode temperature sensor 5 is equal to or greater than a predetermined value, it is considered that scaling has occurred. Therefore, an alarm for prompting cleaning is issued or the power supply is shut off. Take control.

  Inventors that scaling (overheating) is likely to occur at the highest temperature portion of the electrode body having the same voltage (in other words, at a portion where the voltage or power supplied between the electrode bodies changes). In view of the above rule of thumb, when a plurality of heating units 8 are connected and used, it is preferable to provide a temperature sensor at a portion where the voltage changes. For example, each heating is performed as in the case where 500V power is supplied to the first heating unit 8, 400V power is supplied to the second heating unit 8, and 300V power is supplied to the third heating unit 8. When there is a difference in the supply voltage to the unit 8, among the electrodes using the same voltage, at least the most downstream electrode body having the highest temperature is provided with an electrode temperature sensor. Similarly, when a single heating unit is used and different voltages or power are supplied to the electrode bodies in the unit, an electrode temperature sensor is provided at least on the most downstream electrode body among the electrodes using the same voltage. It is preferable. By providing the electrode temperature sensor on the specific electrode body together with the cooling of the electrode body, the overheating can be more effectively prevented.

3 and 4 show an example of the electrode body 43 of the present invention. FIG. 3 shows a cut surface of the flow path of the electrode body 43. The electrode body 43 is provided with a cooling medium flow path 437 concentrically along the inner surface of the heating flow path 41. The cooling medium is supplied from one of the cooling medium supply ports 436 provided in the electrode body, and is discharged from the cooling medium discharge port 436 provided on the opposite side. The electrode body 43 is further provided with a screw hole 433 for power feeding and a hole 434 for mounting a temperature sensor. By providing the cooling medium flow path 437 and circulating the cooling medium, the temperature rise of the electrode body 43 is suppressed, and the food on the inner wall surface of the electrode is prevented from being overheated. It is necessary to efficiently cool the material to be heated by installing the cooling medium flow path as close to the material to be heated as possible. Therefore, the cooling medium flow path 437 is preferably provided closer to the heating flow path 41 than the outer peripheral surface 439 of the electrode body, and at least the heating flow path 41 is more than half of the thickness T in the radial direction of the electrode body 43. It is provided in a range nearer to the heating channel 41, and more preferably in a range closer to the heating channel 41 than １ ／ of the thickness T of the electrode body 43. In order to increase the cooling efficiency, it is preferable to reduce the thickness of the wall 438 that separates the cooling medium flow path and the heating flow path. The thickness of the wall 438 is determined based on the material, strength, thermal conductivity, and overheating of the electrode body 43. Although it is appropriately determined according to the heating characteristics, fluidity, flow rate, temperature of the cooling medium, and the like of the material amount, it is preferably in the range of 5% to 25% of the thickness T of the electrode body 43. . For example, the cooling medium flow path 437 is preferably provided with a wall having a thickness of 1 mm to 5 mm from the inner surface of the electrode body.
As the cooling medium, a liquid cooling medium (for example, water) having high cooling performance is used. The cooling medium is circulated through the cooling medium flow path by a known cooling medium feeding means (not shown) such as a pump.

FIG. 4 shows an example of another electrode body in which the supply port 436 or the discharge port 436 for the cooling medium is provided at a position facing the power supply screw 433. FIG. 4 is a cross-sectional view of the electrode body 43 cut along the heating channel 41, and is provided with a screw hole 433 for feeding and an insertion hole 434 for mounting the insulated electrode temperature sensor 5. A spacer tube 44 is fitted to the fitting portion 435 of the electrode body via a seal member. Since the temperature sensor needs to sense the temperature of the electrode body in contact with the material to be heated, the temperature sensor can be inserted to a position close to the flow path of the cooling medium so as to detect the temperature of the electrode body cooled by the cooling medium. The hole 434 is preferable.
In the configuration of FIG. 4, for example, the thickness T is 20 mm, the thickness of the partition wall 438 is 2 mm, and the diameter of the heating channel 41 is 23 mm.

  As an attachment position of the electrode temperature sensor 5, the downstream side has a long heating time and becomes high temperature, so that it is installed at least in the electrode body 43 of the most downstream heating unit to perform temperature management. Is done. Although it is preferable to provide the temperature sensor 5 on the most downstream ground electrode, the temperature sensor 5 may be provided on other electrode bodies. Depending on the material to be heated, sparks may occur in the middle or downstream of the heating unit 8. In such a case, the electrode temperature sensor 5 is provided on the electrode body 43 located closest to the place where the spark is expected. May be.

The electrode temperature sensor 5 is connected to the temperature measuring device 105. The temperature measuring device 105 includes detection time storage means, and can store the detected temperature of the electrode body 43 and the detection time. The temperature measuring device 105 is connected to the control unit 54, and the power supplied to the electrode body 43 is controlled by the control unit 54 that receives the signal from the temperature measuring device 105, and the temperature and flow rate of the cooling medium are simultaneously controlled. It is controlled to prevent overheating of heated materials such as food materials. The control unit 54 performs PID control on the power supplied to the electrode body 43. The values of the proportional action (P action) and the integral action (I action) in PID control are set appropriately and optimally according to the total length of the energization heating unit 42, the flow rate of the food material, etc. so as not to cause overshoot or cycling. . The control unit 54 is provided with an operation panel 55 having a display means, and can input set values and the like. Further, the control unit 54 has a reporting unit and can issue a cleaning alarm.
In order to control the heating temperature of food in the present invention, scorching due to overheating, generation of scale, etc., it can be performed by controlling the electric power and controlling the cooling medium according to the detected temperature. Control is possible.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

In this example, the temperature of the electrode body was measured by operating a continuous energization heating apparatus using a heating unit using a water-cooled electrode body, using a material to be heated that easily increases the electrode temperature. A comparative study was conducted on the temperature rise of the electrode body depending on whether or not the electrode body was cooled.
A device was constructed and tested according to FIG. Two joule heating pipes (heating unit 8) were connected in series as the preheating section, and one joule heating pipe (heating unit 8) was connected downstream as the heating section to form a joule heating apparatus 13. A cooling double tube having a static mixer was disposed downstream of the Joule heating device.
The arrangement of the electrode bodies in the heating section is as shown in FIG. 2, and the electrode bodies are electrode bodies (water-cooled electrode bodies) having cooling channels. Further, no water-cooled electrode was disposed on the electrode body in the preheating portion.
As the material to be heated, a highly viscous viscous seasoning liquid was used for conducting heating, and it was examined how the temperature of the electrode body changes depending on whether or not the electrode body is cooled. Further, as a comparative test, operation was performed in the same manner using salt water having low viscosity, and the temperature change was compared.
Table 1 shows the instrument conditions used in the test.

  The inlet temperature of the heating part of the sample (viscous seasoning liquid) was 66 ° C, 62 ° C, 58 ° C, and the heating temperature was set to 70 ° C. The flow rate of the viscous seasoning liquid or salt water was 350 L / hr or 175 L / hr, and the electrode cooling medium was 600 L / hr or 300 L / hr as tap water. The test conditions are summarized in Table 2.

  Table 3 shows the test results of the energization heating of the viscous seasoning liquid and the salt water performed under the test conditions 1 to 13. From these results, it was confirmed that the electrode temperature can be prevented from rising even under severe heating conditions by cooling the electrode body. When the temperature of the piping surface at the outlet of the Joule heating device (the piping surface corresponds to the portion of the electrode body 2 to 9 from the inlet side in FIG. 2) was measured, the flow rate was 350 L / hr, 58 ° C. to 70 ° C. The pipe surface temperature when the electrode body was cooled under conditions of heating to ℃ was 75 ° C or more and less than 80 ° C, while the pipe surface temperature when the electrode body was not cooled was 85 ° C or more and less than 90 ° C The temperature rose. By cooling the electrode body, the portion on the tube wall surface where the material to be heated is likely to be overheated was cooled, and temperature variations at the outlet of the energization heating device could be suppressed.

Table 3 shows the test results obtained under conditions 1 to 13. (The numbers of the electrode 3, the electrode 4, the electrode 5, the electrode 6, and the electrode 7 mean the order from the entrance side in the configuration of FIG. 2).
The test results shown in Table 3 demonstrate that the temperature of the electrode body can be lowered and accurately controlled by water-cooling the electrode body regardless of the viscosity of the material to be heated and the flow rate of the cooling water. FIG. 5 is a graph showing the measured temperatures of the electrode bodies in Table 3 for each test condition. From this graph, it is clearer that the electrode temperature is significantly increased under the condition that the electrode is not cooled.
In the conditions 1 to 13, a test condition for making the Joule outlet temperature constant was set, and the Joule outlet temperature was made constant by controlling the voltage.

  A viscous seasoning liquid was used as a material to be heated, an electric heating device having a distance between electrodes of 75 mm was constructed, and the material to be heated was heated at a flow rate of 350 L / hr. The electric heating device is constructed using the members shown in Table 4 and shows the effective length, cross-sectional area, capacity, flow rate, and passage time of each part. This energization heating device is constructed by assembling the members shown in Table 4 in the order of (i) to (iv), and (iii) all of the seven electrode bodies provided in the Joule heating unit constitute a water-cooled electrode. Is. The apparatus was operated for 2 hours at a raw material temperature of 58 ° C. and a heating temperature of 70 ° C., but the electrode temperature was constant at 32.7 ° C., and overheating of the heated material, scorching, and generation of scale were not observed. .

A viscous seasoning liquid was used as the material to be heated, an electric heating device having a distance between electrodes of 100 mm was constructed, and the material to be heated was heated at a flow rate of 0.8 m ³ / hr. The electric heating apparatus used eight Joule heating sections (1S8 section), and the two most downstream were water-cooled electrode type. A static mixer was disposed between the eight joule heating units (heating units). Table 5 shows data such as the effective length, cross-sectional area, capacity, flow rate, and transit time of each part. In Table 5, SP means set temperature, and HDT means actual temperature.
FIG. 6 is a graph showing changes in electrode temperature in each heating unit (joules 1 to 8), and FIG. 7 is a graph comparing the outlet temperature and electrode temperature of each heating unit. In this example, the raw material temperature was 58 ° C. and the heating temperature was 70 ° C., and this apparatus was operated continuously for the time shown in Table 5. However, the increase in electrode temperature was 62 ° C. at maximum and was stable. In addition, it was the 5th electrode and the 6th electrode (non-water cooling type) that the electrode temperature rose most. The reason why the Joule outlet temperature of each heating unit (Joule 1 to 8) and the hold (HDD) outlet temperature coincide with each other is presumed to be that stirring by the static mixer is sufficiently performed.
The flow rate of the electrode cooling water was 432 L / hr, and the return temperature was about + 2 ° C. with respect to the inlet temperature (loss of 860 kcal / h).
Also in this example, overheating of the material to be heated, scorching, and generation of scale were not recognized.

  As described above in detail, the present invention has a plurality of electrode bodies and a plurality of insulating spacers, and by alternately connecting and communicating the electrode bodies and the spacers, a heating flow in which a material to be heated circulates is provided. A cooling medium flow path and a temperature detection are formed in the electrode body of an electric heating device that forms a path and supplies electric power between the electrode bodies while continuously circulating the heated material in the heating flow path to electrically heat the heated material. The present invention relates to a continuous energization heating apparatus provided with a vessel. The present invention makes it possible to provide a continuous energization heating apparatus capable of stable and accurate temperature control, such as high-viscosity fluid foods and foods that are susceptible to thermal denaturation, such as mayonnaise, jam, The present invention provides an optimum heating device for heat-treating proteins such as liquid eggs. The present invention makes it possible to easily perform a heat treatment of a substance that requires delicate heat management, and enables mass production and provision of a substance imparted with new characteristics by a precise heat treatment. The present invention provides a technique useful as a heating apparatus and method particularly useful in the food industry field.

It is a schematic block diagram of the whole continuous current heating apparatus of this invention. It is an expanded sectional view of the heating unit of the present invention. It is front sectional drawing of the electrode body of the heating unit of FIG. It is side surface sectional drawing of the electrode body of another aspect of this invention. It is the temperature change of the electrode body for every conditions obtained in Example 1. FIG. 6 is a graph showing changes in electrode temperature in each heating unit of Example 3. 6 is a graph comparing the outlet temperature of each heating unit of Example 3 and the electrode temperature. It is a flowchart which shows an example of the electricity supply control procedure based on the measured temperature for every heating unit of this invention. It is a flowchart which shows an example of the electricity supply control procedure based on the temperature difference of the exit temperature sensor of this invention, and an electrode temperature sensor.

Explanation of symbols

4 outlet temperature sensor 5 electrode temperature sensor 6 plates 7a, 7b, 7c, 7d flange 8 heating unit 11a, 11b, 11c flow path of material to be heated 12 agitator cooler 21 cooler 22 agitator 13 Joule heating device (continuous energization) Heating device)
41 Heating channel 42 Current heating unit 43 Electrode body (ring-shaped electrode)
44 Spacer 45, 46 Joint
54 Control unit 55 Operation panel 56 Power supply unit 104, 105 Temperature measuring device 43 Electrode body (ring-shaped electrode)
433 Screw hole for power supply connection 434 Temperature measuring instrument insertion hole 435 Insertion part 436 Cooling medium supply / discharge port 437 Cooling medium flow path 438 Partition 439 between heating flow path and cooling medium flow path

Claims (9)

In a continuous energization heating apparatus comprising a heating unit that has a plurality of electrode bodies and a plurality of spacer tubes, and whose inner walls form a heated channel for energization heating while fluidly transferring food material,
The plurality of electrode bodies are configured to include an electrode body provided with a cooling medium flow path,
A continuous type comprising a temperature sensor for detecting an inner wall temperature of the heated channel near the outlet end of the heated channel, and controlling a cooling condition by the liquid cooling medium based on a measured value of the temperature sensor. Electric heating device.   The continuous energization heating apparatus according to claim 1, wherein the temperature sensor is embedded in an electrode body disposed on the most downstream side of the heating unit.   Furthermore, the continuous energization heating apparatus of Claim 2 provided with the temperature sensor embedded at the electrode body arrange | positioned in the uppermost stream of a heating unit.   The continuous energization heating device according to claim 2 or 3, wherein the electrode body in which the temperature sensor is embedded is an electrode body for grounding.   2. The continuous energization according to claim 1, further comprising a joint member disposed at the most downstream side of the heating unit, the joint member being provided on the most downstream side of the heating unit, wherein the temperature sensor is disposed on an inner wall portion of the passage. Heating device.   6. The electrode assembly according to claim 1, wherein the plurality of electrode bodies include an electrode body in which a cooling medium flow path is provided in a range closer to the heating flow path than half of the thickness (T). Continuous electric heating device.   The cooling medium flow path provided in the electrode body is separated from the heating flow path by a wall (438) having a thickness in the range of 5% to 25% of the thickness (T) of the electrode body. The continuous electric heating apparatus as described.   The continuous heating according to any one of claims 1 to 7, wherein a plurality of heating units having one or more electrode temperature sensors are provided, and electric power supplied to each heating unit is controlled based on a measured temperature of each electrode temperature sensor. Type electric heating device. The continuous energization heating device according to any one of claims 1 to 8, wherein the liquid cooling medium is water.