JP2015156349A - Joule heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To energize and heat a food material gelatinized when heated using Joule heat.

SOLUTION: A Joule heating device 10 is used for energizing and heating a food material gelatinized when heated. A heating pipe 12 has electrodes 13a to 13c and spacers 14a, 14b, and a passage 11 is provided in the inside thereof. On a rotary shaft 30 provided in the heating pipe 12, scrape-off plates 41, 42 are provided. In the scrape-off plates 41, 42, scrape-off edges in contact with the inner peripheral surface of the heating pipe 12 are provided. The rotary shaft 30 is supported by electrodes using centering rods 37a, 37c in contact with the inner peripheral surface of the electrodes.

COPYRIGHT: (C)2015,JPO&INPIT

Description

  The present invention relates to a Joule heating device for energizing and heating a food material that gelatinizes when heated.

  Patent Document 1 and Patent Document 2 are used to energize a food material while continuously transporting a fluid food material to a flow path of a heating pipe to cook and heat the food material by Joule heat or to sterilize and heat the food material. Have been developed as described above. The continuous heating device, that is, the Joule heating device described in Patent Document 1, has a heating pipe having a quadrangular cross section, and plate electrodes are provided on two opposing surfaces of the heating pipe. This type of heating pipe is of plate electrode type. On the other hand, the Joule heating device described in Patent Document 2 has a heating pipe formed by a plurality of annular electrodes and a plurality of cylindrical members made of an insulating material, and the heating pipe includes an annular electrode and a cylindrical member. Are alternately arranged and connected. This type of heating pipe is a ring electrode type.

  In these joule heating devices, the food material is heated by energization while flowing through the flow path of the heating pipe. In a Joule heating device having a ring electrode type heating pipe, it is rotated into the heating pipe as described in Patent Document 2 in order to uniformly heat the food material that is energized and heated while being conveyed in the flow path. A stirring member of the type is provided.

  On the other hand, in a joule heating apparatus having a plate electrode type heating pipe, a linear reciprocating scraping member is provided in the heating pipe in order to scrape food material adhering to the electrode plate.

JP-A-2-504331 JP 11-89522 A

  If a linear reciprocating scraping member is provided in the heating pipe as in Patent Document 1, the scraping member increases the flow rate of the food material when the scraping member is driven in the direction of conveying the food material. When the member is driven in the direction opposite to the conveying direction, the food material is driven in the reverse direction by the scraping member, and the food material in the heating pipe cannot be conveyed at a uniform speed as a whole. . On the other hand, when the rotary stirring member is provided in the heating pipe, the food material is transported while being rotated by the stirring member, so that the food material can be transported at a uniform transport speed as a whole.

  Among foods, for example, custard pudding is produced by heating food materials mixed with eggs, sugar, milk and the like. In addition, flour paste is produced by heating a food material in which flour, cocoa, eggs and oils and fats are mixed. In order to mass-produce such food, it is necessary to heat the food material to the cooking temperature and to the sterilization temperature. For example, for mass production of flour paste, after heating to a cooking temperature of about 60-70 ° C., it is further commercialized by heating to a sterilization temperature of less than 100 ° C., for example, about 95 ° C.

  Since custard pudding and flour paste contain starch, when heated to a cooking temperature of about 60 to 70 ° C., the starch is gelatinized and gelatinized. For this reason, food materials that contain a large amount of carbohydrates such as custard pudding and gelatinize when heated can be applied at once by Joule heat from the cooking temperature to the sterilization temperature even when using a stirring member as described in Patent Document 2. Could not heat. The reason for this is that if the material is mixed and then heated while flowing continuously through the heating pipe, the food material flowing on the inner peripheral surface side of the heating pipe, that is, the radial outer periphery of the flow path, is gelatinized and the viscosity increases. On the other hand, the food material flowing in the central portion in the radial direction of the flow path does not gelatinize and remains at a low viscosity.

  Among the food material flowing through the flow path, when the outer peripheral part of the flow path is gelatinized and the central part is not gelatinized, the food material of the outer peripheral part is attached to the inner peripheral surface of the heating pipe, The food material in the central portion passes through the central portion of the flow path without being gelatinized, and a so-called hollow state occurs. Therefore, if the food material that is gelatinized when heated is continuously heated by Joule heat using a heating pipe, the food material cannot be heated uniformly.

  For this reason, in order to cook and sterilize a food material containing a large amount of carbohydrates such as starch, the heat source is externally applied to the cooking temperature while the food material is put in the container. Under the condition that the entire food material is gelatinized by heating to the cooking temperature in the container, heating to the sterilization temperature by Joule heating while continuously conveying the food material into the heating pipe is However, it is possible to heat from normal temperature to a temperature at which gelatinization occurs, but it has not been possible with a conventional Joule heating device. Thus, conventionally, food materials to be gelatinized by heating have been required to be heat-treated in two stages by separate heating methods, the heating step up to the cooking temperature and the heating step up to the sterilization temperature.

  An object of the present invention is to continuously energize and heat a food material containing a carbohydrate such as starch and gelatinizing when heated from ordinary temperature to sterilization temperature by Joule heat.

  The Joule heating device of the present invention is a Joule heating device that energizes and heats food material while continuously conveying the food material gelatinized when heated into a heating pipe, and is composed of a plurality of ring-shaped electrodes and an insulating material. A heating pipe having a cylindrical spacer and provided therein with a flow path for conveying the food material; and provided in the heating pipe at a central portion of the flow path and driven to rotate by a rotation drive source A rotary shaft, a scraping plate attached to a support rod that protrudes radially outward of the rotary shaft, and disposed axially along an inner peripheral surface of the heating pipe; and radially outward of the rotary shaft And a centering rod whose tip end surface is in contact with the inner peripheral surface of the ring-shaped electrode, and on the inner peripheral surface of the heating pipe on the side surface on the front side in the rotation direction of the scraping plate. Scraping edge in contact The provided width dimension of the front end contact surface of the centering rod in the conveying direction of the food material was smaller than the width of the conveying direction of the ring-shaped electrode.

  A scraping plate extending in the axial direction along the inner peripheral surface of the heating pipe is attached to the rotating shaft disposed in the heating pipe by a support rod, and the inner peripheral surface of the heating pipe is attached to the side surface of the scraping plate. A scraping edge is provided that contacts the surface. Even if the food material that gelatinizes when heated is heated to a predetermined temperature by energization heating and gelatinized and adheres to the inner peripheral surface of the heating pipe, the adhered food material is scraped off by the scraping edge, Guided to the radial center. Thereby, the food material gelatinized when heated can be heated while being continuously conveyed from room temperature to the sterilization temperature.

  The rotating shaft is provided with a centering rod, the tip surface of the centering rod is in contact with the inner peripheral surface of the ring-shaped electrode, and the rotating shaft is supported by the electrode via the centering rod. Since the tip contact surface of the centering rod is set to a size smaller than the width of the electrode, the current between the electrodes is not disturbed by the centering rod, and the food material can be efficiently joule heated. it can.

  When the scraping plate is provided with a through hole, the food material guided to the central portion in the shape direction by the scraping plate passes through the through hole and is guided to the gap between the scraping plate and the heating pipe. As a result, the food material does not adhere to the inner peripheral surface of the heating pipe, and the food material in the flow path is agitated by the rotating scraping plate, and is heated to a uniform temperature as a whole. Is done.

It is sectional drawing which shows a Joule heating apparatus. It is a perspective view which shows the rotating shaft and scraping board which were shown by FIG. (A) is a front view which shows a scraping board, (B) is a right view of (A). (A) is the 4A-4A line expanded sectional view in FIG. 1, (B) is the 4B-4B line expanded sectional view in FIG. (A) is the 5A-5A line expanded sectional view in FIG. 1, (B) is the 5B-5B line expanded sectional view in FIG. It is an expanded sectional view of 6 parts shown in FIG. It is a top view which shows the rotating shaft in the Joule heating apparatus which is a modification. (A) is an enlarged left side view of FIG. 7, and (B) is an 8B-B line arrow view in FIG. 8A. It is a disassembled perspective view which shows the front-end | tip part of the rotating shaft shown in FIG. 7, and a scraping board. It is sectional drawing which shows a part of Joule heating apparatus which is a modification. It is the 11-11 line sectional view in FIG. FIG. 12A is an enlarged cross-sectional view of a portion 12 in FIG. 10, and FIGS. 12B and 12C are cross-sectional views showing an inner surface processing step of the electrode shown in FIG. It is sectional drawing which shows the electrode in the Joule heating apparatus which is another modification. It is sectional drawing which shows a part of Joule heating apparatus which is another modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The joule heating device 10 shown in FIG. 1 contains starch such as flour paste, and is used to continuously heat and heat food materials that are gelatinized when heated from normal temperature to cooking temperature to sterilization temperature. Can do. This Joule heating device 10 has a heating pipe 12 in which a flow path 11 for continuously conveying a food material is provided. The heating pipe 12 has three ring-shaped electrodes 13a to 13c and cylindrical spacers 14a and 14b each made of an insulating material, and the electrodes 13a to 13c and the spacers 14a and 14b are alternately arranged in a straight line. The inner peripheral surface of the heating pipe 12 is the same surface as a whole. A seal member (not shown) is sandwiched between the respective abutting surfaces. A pair of two electrodes 13a and 13b that are abutted against both ends of one spacer 14a and are adjacent to each other in the axial direction are paired, and abutted against both ends of the other spacer 14b and adjacent to each other in the axial direction. Two electrodes 13b and 13c arranged together are paired. Each of the electrodes 13a to 13c is connected to the power supply unit 15, and a high-frequency current is supplied from the power supply unit 15 so that two electrodes adjacent to each other in the conveying direction of the food material have opposite polarities. The The joule heating device 10 shown in FIG. 1 has two electrode pairs, but the number of electrode pairs can be arbitrarily set depending on food materials, energization conditions, and the like. The electrodes 13a to 13c are made of an electrode material such as titanium or platinum.

  A ground electrode 16a is abutted against the electrode 13a via a spacer 14c, and a ring-shaped earth electrode 16b is abutted against the electrode 13c via a spacer 14d. The spacers 14c and 14d are made of an insulating material in the same manner as the spacers 14a and 14b. A portion between the ground electrodes 16a and 16b constitutes the heating pipe 12, and an end plate 17a attached to one end of the heating pipe 12 is provided with a straight communication pipe 18, and the heating pipe 12 A curved communication pipe 19 is provided on the end plate 17b attached to the other end. Four fastening rods 21 are attached to both end plates 17a and 17b, and the heating pipe 12 and the communication pipes 18 and 19 are integrally assembled by the fastening rod 21. A fastening plate 22 is disposed to face the end plate 17a, and a spring member 23 is mounted on each fastening rod 21 so as to be positioned between the fastening plate 22 and the end plate 17a. The nut 24 screwed to one end of the fastening rod 21 is abutted against the fastening plate 22, and the fastening force between the heating pipe 12 and the communication pipes 18 and 19 is adjusted by adjusting the fastening amount of the nut 24. Is done. A plurality of support plates 25 are attached to the heating pipe 12, and each fastening rod 21 passes through the support plate 25.

  4A and 4B, the electrodes 13a and 13b are provided with screw holes 26, and power supply lines are connected to the screw holes 26, and the electrodes 13a and 13b are connected to the power supply unit by the power supply lines. 15 is connected. A similar screw hole is formed in the electrode 13c. In addition, you may make it cool an electrode and food material by providing a cooling fluid circulation flow path in each electrode 13a-13c.

  When the communication pipe 18 is the inflow side, a supply pipe (not shown) that supplies unheated food material is connected to the communication pipe 18, and the food material supplied from the supply pipe to the communication pipe 18 passes through the flow path 11. Heat is generated by the current flowing between the electrodes while moving, and Joule heating is performed. The heated food material is conveyed from the communication pipe 19 to the next process, for example, a temperature holding process or a cooling process. In addition, you may make it supply the unheated food material from the communication pipe 19 by making the communication pipe 19 into an inflow side.

  The heating pipe 12 is provided with a rotating shaft 30 positioned at the center thereof. A motor shaft 31 of an electric motor (not shown) serving as a rotational drive source is connected to the rotary shaft 30 through the communication pipe 19, and the rotary shaft 30 is rotationally driven by the motor shaft 31. In order to connect the rotating shaft 30 and the motor shaft 31, a fastening sleeve 32 is fastened to the end of the rotating shaft 30 by a hexagon socket head bolt 33, and a screw rod that is screwed to the hexagon socket head bolt 33. The motor shaft 31 is fastened to the rotary shaft 30 by 34. The motor shaft 31 passes through a guide sleeve 35 fixed to the communication pipe 19. A mechanical seal (not shown) is mounted between the guide sleeve 35 and the fastening sleeve 32, and the food material is connected to the guide sleeve 35. Leakage between the motor shaft 31 and the motor shaft 31 is prevented. In addition, you may make it connect a rotating shaft and the motor shaft 31 via a magnet coupling.

  As shown in FIG. 2, two support rods 36 a are provided at one end portion of the rotating shaft 30 so as to protrude radially outward, and the two support rods 36 a are coaxial. Two centering rods 37a are provided at one end of the rotating shaft 30 so as to protrude radially outward from each support rod 36a with a phase shifted by 90 degrees in the rotational direction. Are coaxial. Four support rods 36b are provided at the central portion in the longitudinal direction of the rotating shaft 30 so as to protrude outward in the radial direction. The position of each support rod 36b in the rotation direction corresponds to the position of the support rod 36a and the centering rod 37a in the rotation direction, and the phases are shifted by 90 degrees in the rotation direction.

  At the other end of the rotating shaft 30, two support rods 36c and two centering rods 37c are provided so as to project outward in the radial direction, similarly to the one end. The rotational positions of the two support rods 36c correspond to the positions of the centering rods 37a, the two centering rods 37c correspond to the positions of the support rods 36b, and the support rods 36c and the centering rods 37c are They are 90 degrees out of phase with each other in the rotational direction.

  The rotary shaft 30 is provided between the support rod 36a and the support rod 36b, and two support rods 38 are provided projecting radially outward. The positions of the support rods 38 in the rotational direction are provided. Corresponds to the position of the support rod 36a. Further, two support rods 38 are provided on the rotary shaft 30 so as to protrude between the support rods 36b and 36c in the radial direction, and the rotation directions of the respective support rods 38 are provided. Corresponds to the position of the support rod 36c.

  The axial distance between the support rod 36a and the support rod 36b corresponds to the distance between the electrode 13a and the electrode 13b, and the axial distance between the support rod 36b and the support rod 36c is the electrode 13b. This corresponds to the distance between the electrode 13c and the electrode 13c. Therefore, as shown in FIG. 1, when the rotating shaft 30 is inserted into the heating pipe 12, the support rods 36a, 36b and 36c can be positioned at the positions of the electrodes 13a, 13b and 13c.

  Two strip-shaped scraping plates 41 are provided as a pair on one end side of the rotating shaft 30. Each scraping plate 41 is disposed in the axial direction along the inner peripheral surface of the heating pipe 12, and both end portions are attached to the support rod 36 a and the support rod 36 b, and the longitudinal center portion is attached by the support rod 38. It is done. Two scraping plates 42 are provided as a pair on the other end side of the rotating shaft 30. Each scraping plate 42 is disposed in the axial direction along the inner peripheral surface of the heating pipe 12, and both ends are attached to the support rod 36 b and the support rod 36 c, as well as the scraping plate 41. The central portion in the longitudinal direction is attached by 38. The rotating shaft 30 shown in FIG. 2 is provided with two pairs of a scraping plate pair composed of two scraping plates 41 and a scraping plate pair composed of two scraping plates 42. The scraper plate pair is 90 degrees out of phase in the rotational direction. As described above, the rotating shaft 30 is provided with a plurality of pairs of scraping plates. Each scraping plate 41, 42 is formed with a fitting hole 43 into which a small diameter portion provided at the tip of the support rod enters.

  As the material of the rotating shaft 30 including the support rod and the centering rod and the material of the scraping plates 41 and 42, an insulating material is used so that no current flows from the electrodes. As the material, polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polyether ether ketone, or polyphenylene sulfide can be used. Moreover, it is also possible to use a metal material as the rotating shaft 30, and in that case, the surface is covered with an insulating layer. As the material for the insulating layer, any of the above-mentioned polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, polyether ether ketone, or polyphenylene sulfide can be used.

  Assuming that the rotation direction of the rotation shaft 30 is the direction indicated by the arrow in FIG. 2, the rotation shaft 30 is shown as being rotated 90 degrees in FIG. An inclined surface 44 inclined at an angle θ from the outer surface toward the inner surface is formed on the side surface of each scraping plate 41, 42 on the front side in the rotational direction, and intersects the inclined surface 44 and the outer surface. A scraping edge 45 is formed by the portion. As shown in FIGS. 4 and 5, the scraping edge 45 formed on the side surface of the scraping plates 41 and 42 is in contact with the inner peripheral surface of the heating pipe. In the illustrated case, the inclination angle θ is set to 45 degrees.

  As shown in FIG. 4A, when the dimension between the tip surfaces of the two support rods 36a is L0 and the dimension between the tip surfaces of the two centering rods 37a is L1, the dimension L1 is a heating pipe. This corresponds approximately to the inner diameter of 12. The dimension between the tip surfaces of the other two centering rods 37c is also L1, and the dimension between the tip surfaces of the other support rods 36b and 36c is also L0. The dimension L0 between the end faces of the support rod is set to be smaller than the dimension L1 between the end faces of the centering rod, and there is a gap between the scraping plates 41, 42 and the inner peripheral surface of the heating pipe 12. 46 is provided. The respective centering rods 37a and 37c are positioned on the inner peripheral surfaces of the electrodes 13a and 13c. As a result, the tips of the centering rods 37a and 37c come into contact with the inner peripheral surfaces of the electrodes 13a and 13c, and the rotary shaft 30 is supported by the electrodes 13a and 13c via the centering rods 37a and 37c at both ends. It will be. The electrodes 13a to 13c are made of metal, have higher hardness than the resin spacers 14a to 14d, and have higher wear resistance than the spacers. By making the centering rods 37a and 37b contact the inner peripheral surface of the spacer without contacting the inner peripheral surface of the spacer, the durability of the rotary shaft 30 is improved as compared with the case of contacting the inner peripheral surface of the spacer. be able to.

  When surface hardening treatment is performed on the inner peripheral surfaces of the electrodes 13a to 13c, the wear resistance of the electrodes 13a to 13c can be further improved. When an insulating surface-cured layer is applied to the inner peripheral surfaces of the electrodes 13a to 13c, the surface-cured layer is applied only to the central portion of the electrodes 13a to 13c in the direction of the food conveying material. On the other hand, when a conductive surface-cured layer is applied to the inner peripheral surfaces of the electrodes 13a to 13c, the surface-cured layer may be applied to the entire inner peripheral surface.

  As shown in FIG. 6, the outer diameter d of the centering rod 37c is set smaller than the width dimension W of the electrode 13c, and the front end surface of the centering rod 37c is a convex surface 39 protruding outward. That is, the central portion in the food conveyance direction protrudes outward. The rotation direction of the centering rod 37c is a curved surface corresponding to the inner peripheral surface of the electrode. The same applies to the other centering rods 37a. Accordingly, the inner peripheral edges of the electrodes 13a and 13c are not partially covered by the centering rods 37a and 37c. Since the electric current F flowing between the electrodes 13a to 13c through the food material mainly flows from the edge E portion of the inner peripheral surface of the electrodes 13a to 13c, the edge E portion is aligned with the centering rods 37a and 37c. The food material can be reliably heated and energized without being covered or disturbed by the front end surface.

  Thus, by making the outer diameter d smaller than the width dimension W, the width dimension of the tip contact surface of the centering rod 37c in the food material conveyance direction is made smaller than the width dimension in the electrode conveyance direction. . However, if the width of the convex surface 39 in contact with the inner peripheral surface of the electrode, that is, the width of the tip contact surface in the conveying direction can be made smaller than the width of the electrode, the outer diameters of the bases of the centering rods 37a and 37c are It may be larger than the width dimension W.

  As shown in FIGS. 2 and 3, each scraper plate 41, 42 is formed with a plurality of through-holes 47 made of elongated holes extending in the longitudinal direction. As indicated by arrows in FIG. 5B, when the scraping plates 41, 42 rotate with the rotation of the rotary shaft 30, the food material adhering to the inner peripheral surface of the heating pipe 12 is scraped by the scraping edge 45. It is taken off, peeled off from the inner peripheral surface, guided to the inclined surface 44 and guided to the center side of the flow path 11. The food material guided to the center side is returned to the gap 46 between the scraping plates 41 and 42 and the inner peripheral surface of the heating pipe 12 through the through hole 47. As a result, the food material is prevented from adhering to the inner peripheral surface of the heating pipe 12 and the fluidized food material is always supplied to the gap 46. The gap 46 is an outer peripheral portion of the flow path 11 in the heating pipe 12, and a larger current flows than the center portion. Therefore, the food material can be efficiently heated by guiding the food material to the gap 46. it can.

  The joule heating device 10 described above can be applied to a case where a food material that is gelatinized when heated, such as a flour paste, is energized and heated. In the flour paste, food materials are prepared by stirring flour, cocoa, eggs and the like. The prepared food material of flour paste is put into, for example, a hopper (not shown), and is continuously supplied from the hopper to the communication pipe 18 by a pump. The food material of the flour paste supplied from the communication pipe 18 into the heating pipe 12 is in a state where the four scraping plates 41 and 42 are rotationally driven by rotationally driving the rotary shaft 30 by an electric motor. Thus, the flow path 11 is conveyed from the upstream side toward the downstream side. When power is supplied from the power supply unit 15 to the electrodes 13a to 13c, a current flows between the electrodes via the food material, and the food material is heated by energization.

  Since the food material contains starch, for example, when the food material is heated to a temperature of about 60 to 70 ° C., the starch is gelatinized, that is, becomes α, and adheres to the inner peripheral surface of the heating pipe 12. When the gelatinized starch remains attached to the inner peripheral surface of the heating pipe 12, the portion is overheated, whereas the food material flowing through the central portion in the radial direction of the flow path 11 is not heated to a predetermined temperature. . In this joule heating device 10, scraping plates 41 and 42 are disposed in the flow path 11 along the inner peripheral surface of the heating pipe 12 in the axial direction, and the scraping plates provided on the side surfaces of the scraping plates 41 and 42 are disposed. The food material adhering to the inner peripheral surface of the heating pipe 12 is scraped off by the take-off edge 45. The scraped food material is guided to the central portion of the flow path 11 by the inclined surface 44 and is drawn into the gap 46 so as to be drawn through the through hole 47 as indicated by an arrow in FIG. Supplied. Accordingly, even if the food material is gelatinized, the gelatinized food material is prevented from adhering to the inner peripheral surface of the heating pipe 12, and the food material in the flow path 11 is stirred and continuously downstream. To be transported. By the time the food material is carried out from the downstream side, the food material is continuously heated by energization to a sterilization temperature of 90 to 130 ° C. higher than the cooking temperature.

  7-9 shows the rotating shaft which is a modification of a Joule heating apparatus. In these figures, the same reference numerals are given to members common to the constituent members of the joule heating device described above.

  Both ends of the scraping plate 41 are attached to the support rods 36a and 36b shown in FIG. 7 in the same manner as shown in FIG. 2, and both ends of the scraping plate 42 are respectively attached to the support rods 36b and 36c. Is attached in the same manner as shown in FIG. Each scraping plate 41, 42 has the same shape as that shown in FIGS. Further, like the rotary shaft 30 shown in FIG. 2, a centering rod 37 a protrudes in the radial direction at the front end portion of the rotary shaft 30, and a centering rod 37 c protrudes in the radial direction at the rear end portion of the rotary shaft 30. ing.

  As shown in FIG. 7, the tip of the rotating shaft 30 is provided with a conical pointed convex portion 51. When the communication pipe 18 is on the inflow side, as shown in FIG. Compared with the case where the tip portion of the shaft 30 is flat, the food material does not adhere to the tip portion of the rotating shaft 30.

  As shown in FIGS. 8 and 9, the support rod 36 a and the centering rod 37 a have a streamlined outer peripheral surface along the rotation direction. The other support rods 36b and 36c, the other centering rod 37c, and the support rod 38 have the same shape. The outer peripheral surface 52 on the front side in the conveyance direction of the food material of each support rod and the centering rod and the outer peripheral surface 53 on the rear side in the conveyance direction are streamlined, and the width dimensions in the respective rotation directions are shown in FIG. Assuming that d1 is as shown in A) and the width dimension in the transport direction is d2 as shown in FIG. 8B, the width dimension d1 in the rotation direction is larger than the width dimension d2 in the transport direction. .

  The support rod and the centering rod shown in FIG. 2 have a circular cross section, whereas the support rod and the centering rod shown in FIGS. It is set to a larger value than the case. As shown in FIGS. 7 to 9, the outer peripheral surfaces 52 and 53 are streamlined, and a stirring edge is formed by the cross lines 54 and 55 where both the outer peripheral surfaces 52 and 53 intersect. The cross line 54 as a stirring edge is located on one side in the rotational direction, and the cross line 55 is located on the other side. Accordingly, when the scraping plates 41 and 42 are rotated by the rotating shaft 30, it is possible to suppress the food material from adhering to the support rod and the stirring rod as compared to the case where the scraper plates 41 and 42 are circular.

  As shown in FIG. 9, the thickness dimensions of the support rods 36 a to 36 c are smaller than the inner diameter of the fitting hole 43. A small-diameter portion 56 that fits into the fitting hole 43 is provided at the distal end portion of each support rod. The small-diameter portion 56 has a long-diameter portion corresponding to the inner diameter of the fitting hole 43 and a width dimension smaller than this. And a short diameter portion set to be small. A small-diameter portion 57 similar to the support rod is also provided at the tip of the centering rods 37a and 37c, and the centering rod can be manufactured using the same material as the support rod. However, as shown in FIG. 8 (A), the tip surfaces of the small diameter portions 57 of the centering rods 37a and 37c are curved in the circumferential direction in correspondence with the inner peripheral surface of the electrode. Similar to the case shown, the convex surface protrudes in the direction of food conveyance.

  10 is a cross-sectional view showing a part of a Joule heating device which is another modification, FIG. 11 is a cross-sectional view taken along line 11-11 in FIG. 10, and FIG. 12A is an enlarged view of a portion 12 in FIG. FIGS. 12B and 12C are cross-sectional views showing an inner surface processing step of the electrode shown in FIG.

  FIG. 10 shows an enlarged view of the ring-shaped electrode 13a shown in FIG. 1 and portions corresponding to part of the spacers 14a and 14c arranged on both sides thereof. As shown in FIGS. 10 and 11, the electrode 13 a has an annular coolant circulation channel 64 formed therein. The electrode 13a is provided with a screw hole 65 for circulating a coolant in addition to a screw hole 26 for connecting a power supply line. A power supply plug to which a power supply line is connected is attached to the screw hole 26. On the other hand, a pipe joint for guiding the coolant is attached to the two screw holes 65, and the coolant supplied from the supply-side pipe attached to the one screw hole 65 flows through the coolant circulation passage 64. And discharged to the piping on the discharge side attached to the other screw hole 65. In this way, the electrode 13b is cooled by the coolant flowing through the coolant circulation channel 64.

  Seal members 66 are disposed between both end faces of the electrode 13a and the spacers 14a and 14c. Each seal member 66 is annular, and positioning projections 67 are provided on both surfaces.

  The inner peripheral surface of the electrode 13a has a hard material surface 68 in the central portion in the axial direction and current-carrying surfaces 69 on both sides thereof. The hard material surface 68 is formed by providing a hard material layer 70 made of a hard material in a concave groove formed on the inner peripheral surface of the inner ring 61. As the hard material for forming the hard material layer 70, tungsten carbide (WC) as hard ceramics is used. However, the hard material is not limited to this, and other hard ceramics such as titanium nitride (TiN) may be used.

  The tip surface of the centering rod 37a shown in FIGS. 2 and 9 is in contact with the hard material surface 68 of the electrode 13a. Thus, when the tip surface of the centering rod 37a is brought into contact with the hard material surface 68, the electrode is compared with the case where the tip surface of the centering rod 37a is brought into direct contact with the inner peripheral surface of the titanium electrode. The wear resistance of the portion of the inner peripheral surface of 13a where the tip surface of the centering rod 37a contacts can be improved, and the durability of the electrode 13a can be improved.

  The current-carrying surfaces 69 provided at both ends of the inner peripheral surface of the electrode 13a are not provided with the hard material layer 70 and are exposed. As shown in FIG. 6, since the current flowing between the electrodes 13a to 13c through the food material flows mainly from the edge portion of the inner peripheral surface of the electrodes 13a to 13c, the hard material layer 70 is the electrode. Even if it is provided at the axially central portion of the inner peripheral surface of 13a, the food material can be reliably heated by energization. The thickness dimension in the axial direction of the illustrated electrode 13a is about 20 mm, and the thickness dimension in the radial direction of the hard material layer 70 is about 0.15 mm.

  In order to form the hard material layer 70 on the electrode 13a, as shown in FIG. 12B, an annular groove 71 is formed on the inner peripheral surface of the electrode 13a. Under this state, as shown in FIG. 12C, the hard material 70a is coated on the entire inner peripheral surface of the inner ring 61 by a surface treatment technique such as thermal spraying. When coated, since the hard material 70a is also coated on the current-carrying surfaces 69 at both ends of the inner peripheral surface, the entire inner peripheral surface is removed in order to remove the hard material 70a coated on the current-carrying surface 69. The current-carrying surface 69 is exposed by grinding. As a result, as shown in FIG. 12A, the current-carrying surfaces 69 are exposed at both ends of the inner peripheral surface, and a hard material surface 68 made of the hard material layer 70 is formed at the center.

  10 to 12 show the electrode 13a shown in FIG. 1, the electrode 13c has the same structure.

  FIG. 13 is a cross-sectional view showing an electrode in a Joule heating apparatus which is still another modification, and shows a portion corresponding to the electrode 13a shown in FIG. However, the other electrodes 13c have the same structure. The electrode 13 a has an inner ring 61 and an outer ring 62, and the inner ring 61 is fitted in close contact with the inner peripheral surface of the outer ring 62. The outer ring 62 is made of another conductive metal such as titanium or stainless steel. The inner ring 61 is made of tungsten carbide (WC). Unlike the electrodes shown in FIGS. 11 and 12, the inner ring 61 itself is made of a hard material, and its inner peripheral surface is hard. A material surface 68 is provided.

  An annular groove 63 is formed at the axially central portion of the outer peripheral surface of the inner ring 61, and a coolant circulation channel 64 is formed by the annular groove 63 and the inner peripheral surface of the outer ring 62. The inner ring 61 is made of titanium, the energization ring 72 is made of titanium, and the inner peripheral surface of the energization ring 72 is an energization surface 69. Further, the electrode 13 a has two energization rings 72, and the energization ring 72 is abutted against the end faces of the inner ring 61 and the outer ring 62 via a seal member 73. Thus, the hard material surface 68 and the current-carrying surface 69 are formed of different members in the electrode shown in FIG.

  The energization ring 72 is fastened to the outer ring 62 by a screw member 74 made of a conductive material, and the energization ring 72 is electrically connected to the outer ring 62 made of a conductive material via the screw member 74.

  As described above, the hard material layer 70 may be provided on the inner peripheral surface of the electrode, and the hard material surface 68 may be formed by the inner surface thereof, and the inner ring 61 itself that is a member constituting the electrode is formed of the hard material. However, the hard material surface 68 may be formed by the inner surface of the hard material. Although the centering rod 37a does not contact the electrode 13b shown in FIG. 1, the electrode 13b having the structure shown in FIGS. 10 to 13 may also be used.

  Further, unlike the electrodes shown in FIGS. 1 and 6, the inner ring and the outer ring are not provided, and the integrated electrode is provided with a hard material surface 68 at the central portion of the inner peripheral surface thereof. The energizing surfaces 69 may be provided at both ends in the axial direction.

  FIG. 14 is a cross-sectional view showing a part of a Joule heating device which is a modified example, and FIG. 14 shows two scraping plate 41 portions. In this Joule heating device, the centering rods 37 a and 37 c are not provided, and the rotating shaft 30 is centered on the heating pipe 12 by bringing the scraping plate 41 into contact with the inner peripheral surface of the heating pipe 12. Supported. The support rods 36 a, 36 b and 38 are fitted in the fitting groove 43 a, and the tip end surface of the support rod is not exposed on the inner peripheral surface of the heating pipe 12. As described above, the centering of the rotating shaft 30 may be performed by the scraping plate 41 instead of the centering rod. As the centering mode of the rotating shaft 30, the centering by the scraping plate 41 is performed. And a form using a centering rod.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the joule heating device 10 described above has four scraping plates, but by providing at least one scraping plate in the heating pipe 12, the heating pipe resulting from gelatinization of the food material Adhesion to the inner peripheral surface can be prevented.

DESCRIPTION OF SYMBOLS 10 Joule heating apparatus 11 Flow path 12 Heating pipe 13a-13c Electrode 14a-14d Spacer 15 Power supply unit 18, 19 Communication pipe 21 Fastening rod 30 Rotating shaft 31 Motor shaft 36a, 36c Support rod 37a, 37c Centering rod 39 Convex surface 41, 42 scraping plate 44 inclined surface 45 scraping edge 46 gap 47 through-holes 52, 53 outer peripheral surfaces 54, 55 crossing line (stirring edge)
61 Inner ring 62 Outer ring 64 Coolant circulation channel 68 Hard material surface 69 Current-carrying surface 70 Hard material layer

Claims (11)

A Joule heating device that energizes and heats food material while continuously conveying the food material that is gelatinized when heated into a heating pipe,
A heating pipe provided with a plurality of ring-shaped electrodes and a cylindrical spacer made of an insulating material, and provided with a flow path for conveying the food material therein;
A rotating shaft that is provided in the heating pipe at the center of the flow path and is driven to rotate by a rotation driving source;
A scraping plate attached to a support rod projecting radially outward of the rotating shaft, and disposed in an axial direction along an inner peripheral surface of the heating pipe;
A centering rod that protrudes radially outward from the rotating shaft and has a tip surface that contacts the inner peripheral surface of the ring-shaped electrode;
A scraping edge that contacts the inner peripheral surface of the heating pipe is provided on the side surface on the front side in the rotational direction of the scraping plate,
A Joule heating device in which the width dimension of the tip contact surface of the centering rod in the conveyance direction of the food material is smaller than the width dimension of the ring-shaped electrode in the conveyance direction.   2. The joule heating device according to claim 1, wherein the food material peeled off by the scraping plate and returned to the center side of the flow path is guided between the scraping plate and the inner peripheral surface of the heating pipe. A Joule heating device provided with holes in the scraping plate.   The joule heating device according to claim 1 or 2, wherein an outer peripheral surface along a rotation direction of the centering rod and the support rod is a streamline type.   The joule heating device according to any one of claims 1 to 3, wherein a hard material surface made of a hard material is formed on a portion of the inner peripheral surface of the electrode that contacts the centering rod.   5. The joule heating device according to claim 4, wherein a concave groove is formed on an inner peripheral surface of the electrode, a hard material layer made of a hard material is coated in the concave groove, and the hard surface is formed by an inner peripheral surface of the hard material layer. Joule heating device with material surface. A Joule heating device that energizes and heats food material while continuously conveying the food material that is gelatinized when heated into a heating pipe,
A heating pipe provided with a plurality of ring-shaped electrodes and a cylindrical spacer made of an insulating material, and provided with a flow path for conveying the food material therein;
A rotating shaft that is provided in the heating pipe at the center of the flow path and is driven to rotate by a rotation driving source;
A scraping plate provided on the rotating shaft and disposed in the axial direction along the inner peripheral surface of the heating pipe;
A scraping edge that contacts the inner peripheral surface of the heating pipe is provided on the side surface on the front side in the rotational direction of the scraping plate,
A through hole is provided in the scraping plate for guiding the food material peeled off by the scraping plate and returned to the center side of the flow path between the scraping plate and the inner peripheral surface of the heating pipe. Joule heating device.   The joule heating device according to any one of claims 1 to 6, wherein a stirring edge is formed by a cross line where the outer peripheral surface on the front side in the transport direction and the outer peripheral surface on the rear side in the transport direction intersect. .   The joule heating device according to any one of claims 1 to 7, wherein a plurality of scraping plates are provided on the rotary shaft in pairs with the rotational axis shifted in a rotational direction. .   9. The joule heating device according to claim 8, wherein a plurality of pairs of scraping plates paired by a plurality of the scraping plates are provided adjacent to each other in the axial direction on the rotating shaft, and the scraping plate pairs adjacent to each other in the axial direction are scraped. A Joule heating device that shifts the phase of the catch plate in the rotational direction.   The joule heating device according to any one of claims 1 to 9, wherein an end portion of the scraping plate is positioned on an inner peripheral surface of the electrode.   The joule heating device according to any one of claims 1 to 10, wherein the food material is continuously heated to a sterilization temperature of 90 to 130 ° C, which is higher than the cooking temperature.

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