JP2010267401A - Heating electrode and method for heating material to be heated using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating electrode capable of matching a load and the impedance of a high-frequency power source without decreasing efficiency of heating the material to be heated, and to provide a method for heating the material to be heated using the heating electrode. <P>SOLUTION: An aggregate of a plurality of pin electrodes 10 consisting of conductive pins is slidably arranged in a through hole 21 of a pin support 20, and a pressure-variable gas chamber 30 in which a pressure can be varied is connected to the pin support 20. In addition, the pin electrodes 10 are arranged in through holes 41 of a load regulation electrode 40 in conductive and sliding form to axially drive the pin electrodes 10 by increasing or decreasing the pressure in the pressure-variable gas chamber 30, while the load regulation electrode 40 is driven separately and independently of the pin electrodes 10 by a position-variable mechanism 42. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heating electrode and a heating method of a heated material using the heating electrode, and more particularly to a heating electrode capable of matching the impedance of a load and a high frequency power supply without reducing the heating efficiency of the heated material and the heating electrode. The present invention relates to a heating method for the material to be heated.

The dielectric heating method, which is one of the methods for electrically heating food materials, applies a high-frequency voltage to the material to be heated (dielectric material), changes the polarity of each molecule constituting the material to be heated at a high frequency, and accompanies it. This is a method of heating a material to be heated by internal heat generation caused by rotation, collision, vibration, friction, etc. of molecules. Therefore, the dielectric heating method has an advantage that the surface of the food can be deeply heated without overheating the food. The principle of dielectric heating is theoretically explained by the equivalent circuit shown in FIG. 10 and its vector diagram. That is, since the internal resistance (r) exists in the dielectric, the equivalent circuit is a circuit in which the capacitance (C) and the internal resistance (r) are connected in parallel. Therefore, when an alternating voltage having a frequency f [Hz] and an effective value V is applied to this dielectric, a current component (I _r ) in phase with the alternating voltage flows inside the dielectric, which corresponds to I _r × V inside the dielectric. to power P _r it is consumed as heat. Its power P per unit area [W / m ^2] is known to be expressed by the proportional expression below.
P∝f × E ² × ε _r × tanδ
Here, E is the electric field strength [V / cm], f is the frequency [Hz] of the power source, ε _r is the relative permittivity, and tan δ is the dielectric loss angle. In particular, the product epsilon _r tan [delta between the relative permittivity epsilon _r and the dielectric loss angle tan [delta called loss factor, calorific value the higher the value of the loss factor increases. Further, as the heating proceeds, the dielectric loss angle tanδ of the heated material changes, and the impedance of the entire load including the heated material also changes. As a result, the impedances of the load and the high frequency power supply do not match. When the impedances of the load and the high-frequency power source do not match, a part of the transmission power of the high-frequency power source is reflected by the load, and the transmission efficiency for the load is reduced. Therefore, normally, a matching circuit for matching both impedances is provided between the load and the high frequency power supply (see, for example, Patent Document 1).
By the way, since the impedance of the entire load including the material to be heated is generally expressed as Z _L = R + jωL + 1 / (jωC), the impedance of the load can be changed by changing any of the resistance R, reactance L, or capacitance C. Z _L can be adjusted.
As a method of matching the impedance of the load and the high frequency power supply, the heating electrode is composed of three electrode plates, the middle electrode plate is a movable electrode plate, the outside is a fixed electrode plate, and the fixed electrode plates are short-circuited. Then, by applying a high-frequency voltage between the movable electrode plate and one fixed electrode plate, and moving the movable electrode plate in the middle to change the capacitance on the load side as necessary, matching the impedance between the load and the high-frequency power supply A dielectric heating apparatus that takes the following is known (for example, see Patent Document 1).

JP 2004-340471 A Japanese Patent No. 3249701

The load of the dielectric heating device is equivalent to a circuit in which two capacitors (resonance circuit unit 14 and capacitance stabilizing capacitor 21) are coupled in parallel. Therefore, by moving the movable electrode plate, the electrode plate interval of each capacitor is changed, and each capacitance is changed to adjust the load impedance to a desired value. At this time, the function of dielectrically heating the material to be heated is performed by the resonance circuit unit 14 facing the material to be heated.
However, in the above dielectric heating device, when matching the impedance of the load and the high frequency power supply, a gap may be formed between the material to be heated and the electrode plate, or the gap may be further expanded. The gap between the material to be heated and the electrode plate weakens the electrical action (especially, the electric field E acts as a square) that the electrode plate acts on the material to be heated, and between the electrode plates (in this case, movable) The relative dielectric constant ε _r between the electrode plate and the fixed electrode plate is reduced. As a result, the heat generation amount P in the heated material is reduced. By the way, an electrode plate may function also as a heat exchanger plate which heats a to-be-heated material by heat conduction other than an electrical effect | action. In that case, when a gap is generated between the heated material and the electrode plate, heat is hardly transferred to the heated material. As described above, when a gap is generated between the electrode plate and the material to be heated, the electric action on the material to be heated is weakened during dielectric heating, while the heat to the material to be heated is reduced during heating by heat conduction. As a result, there arises a problem that the heating efficiency for the material to be heated is lowered.
Therefore, the present invention has been made in view of the problems of the prior art, and the object thereof is to match the impedance of the load and the high frequency power supply without reducing the heating efficiency for the material to be heated. It is providing the heating electrode and the heating method of the to-be-heated material using the same.

In order to achieve the above object, the heating electrode according to claim 1 is a heating electrode that is disposed to face and holds and heats the heated material, a holding electrode portion that holds the heated material, and the holding electrode And a load adjustment unit that is electrically connected to the unit and can be independently displaced.
The heating electrode is configured so that the load adjusting unit can be independently displaced with respect to the holding electrode unit holding the material to be heated. For this reason, it becomes possible to match the impedance of the load and the power supply while holding the heated material. That is, the heating electrode can match the impedance of the load and the high-frequency power source by the load adjusting unit without forming a gap between the heated material and the holding electrode unit. At that time, the holding electrode portion holds the material to be heated and does not weaken the electrical and thermal effects on the material to be heated, so that the heating efficiency for the material to be heated is suitably maintained.

In the heating electrode according to claim 2, the holding electrode portion and the load adjusting portion are integrated.
With the above-described configuration, the heating electrode can easily match the impedance of the load and the high-frequency power source, and can further integrate the entire apparatus in a compact manner.

In the heating electrode according to claim 3, the holding electrode portion follows the shape of the material to be heated.
With the above-described configuration, the heating electrode can uniformly and efficiently heat the heated material without depending on the shape of the heated material.

In the heating electrode according to claim 4, the holding electrode portion is a pin electrode.
With the above-described configuration, the heating electrode can easily follow the shape of the material to be heated.

In order to achieve the above object, in the method for heating a material to be heated according to claim 5, the material to be heated is heated by a heating electrode comprising a holding electrode part for holding the material to be heated and a load adjusting part for matching impedance. Heating method
While holding the material to be heated by the holding electrode unit, the impedance matching is achieved by displacing the load adjusting unit independently with respect to the holding electrode unit.
In the heating method of the material to be heated, in order to match the impedance of the load and the high frequency power source while the material to be heated is held by the holding electrode portion, while displacing the load adjustment unit independently with respect to the holding electrode portion, It is possible to match the impedance between the load and the high-frequency power source without affecting the heating state of the holding electrode portion with respect to the material to be heated.

  According to the heating electrode of the present invention and the heating method of the heated material using the heating electrode, the impedance of the load and the high-frequency power source can be reduced without creating a gap between the holding electrode portion that holds the heated material and the heated material. It is possible to achieve consistency. Thereby, the fall of the heating efficiency with respect to the to-be-heated material at the time of impedance matching can be prevented suitably. In addition, when at least one of the heating electrodes is a pin electrode, in order to appropriately follow the shape of the material to be heated, the impedance of the load and the high-frequency power source are matched, and the shape of the material to be heated is not affected. It becomes possible to heat the material to be heated uniformly.

It is principal part cross-sectional explanatory drawing which shows the heating electrode which concerns on the heating electrode of this invention. It is explanatory drawing which shows the example of a heating of the foodstuff by the heating electrode which concerns on the heating electrode of this invention. It is principal part cross-sectional explanatory drawing which shows the pin support stand which concerns on Example 1. FIG. 6 is an explanatory view showing a heating method using a heating electrode according to Example 2. FIG. FIG. 6 is a cross-sectional explanatory view of a main part showing a heating electrode according to Example 3. It is explanatory drawing which shows the heating method of the foodstuff using the said heating electrode. It is explanatory drawing which shows the heating method of the foodstuff using the heating electrode which concerns on Example 5. FIG. FIG. 10 is an explanatory cross-sectional view of a main part showing a heating electrode according to Example 6. 10 is an explanatory view showing a heating electrode according to Example 7. FIG. It is explanatory drawing which shows the principle of a dielectric heating method.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings.

FIG. 1 is an explanatory cross-sectional view of a main part showing a heating electrode 100 of the present invention.
The heating electrode 100 includes a plurality of pin electrodes 10 serving as holding electrode portions that are in contact with a material to be heated and exerting an electrical or thermal action, and each pin electrode 10 is slidably supported and a power source for the pin electrode 10 Alternatively, a pin support base 20 as a conductive base serving as a heat source, a pressure variable gas chamber 30 that displaces the pin electrode 10 relative to the pin support base 20, and a dielectric heating by applying a high-frequency electric field to the material to be heated. A load adjustment electrode 40 as a load adjustment unit that matches the impedance of the load and the high frequency power supply is provided.

The load adjustment electrode 40 is configured to be able to displace independently from the pin electrode 10 while being electrically connected to the pin electrode 10. Therefore, the load adjusting electrode 40 is provided with a through hole 41 through which the pin electrode 10 is slidable and slidable, and is itself driven by the position variable mechanism 42. On the other hand, the pin electrode 10 is driven in the axial direction by the pressure variable gas chamber 30 while sliding on the load adjusting electrode 40. Therefore, the load adjustment electrode 40 and the pin electrode 10 can be relatively displaced independently while always maintaining the same potential. Therefore, the heating electrode 100 does not affect the electrical and / or thermal action of the pin electrode 10 on the heated material in a state where the pin electrode 10 is in contact with the heated material. Can be matched independently of the pin electrode 10 to match the impedance between the load and the high-frequency power source.
In addition to the structure penetrating the other as described above, the electrode holding portion and the load adjusting portion may be an integrated structure having a concavo-convex structure that is electrically conductive and slidable, such as fitting.

  For example, a slide mechanism can be adopted as the position variable mechanism 42. The position variable mechanism 42 is attached to the pin support 20 in a built-in or external form, and is configured integrally with the pin electrode 10 electrically and mechanically.

  Examples of the material of the load adjustment electrode 40 include conductive materials such as aluminum, copper, titanium, and platinum.

  The pin electrode 10 is an electrical or thermal contact with the pin head 11 that directly contacts the food and the pin head 11 and defines the amount of movement (stroke) of the pin electrode 10 relative to the pin support base 20. It consists of a rod 12 and a pin cap 13 that defines the end position of the pin head 11 and functions as a stopper.

  The pin head 11 has, for example, a shape in which a hemispherical portion and a cylindrical portion are combined, and the rod 12 has, for example, an elongated cylindrical shape, and one end is screwed to the pin cap 13 and the other end is screwed. ing. Further, the rod 12 is inserted into a through-hole 21 described later and serves as an electrical or thermal contact with the pin support base 20.

  In addition, about the coupling | bonding of the pin head 11 and the rod 12, although the screw coupling | bonding which can replace | exchange a pin head according to the shape of a foodstuff is preferable, you may form integrally, such as cutting and welding. Alternatively, the rod 12 and the pin cap 13 may be integrally formed by cutting, welding, caulking, etc., and the pin head 11 and the rod 12 may be screwed together.

  The material of the pin head 11, the rod 12 and the pin cap 13 is the same conductive material as aluminum, copper, carbon, titanium, platinum, etc., as in the load adjusting electrode plate.

  The pin support 20 is provided with a through-hole 21 in which the pin electrode 10 slides and relatively displaces independently for each pin electrode 10. The inner diameter of the through hole 21 is slightly larger than the outer diameter of the rod 12 of the pin electrode 10. Thereby, each pin electrode 10 can be relatively displaced in the axial direction separately from the pin support base 20 while energizing or transferring heat with the pin support base 20, and can suitably follow the shape of the foodstuff.

  By the way, the drive of the pin electrode 10 is performed by changing the internal pressure of the pressure variable gas chamber 30, as will be described later. Therefore, the clearance between the rod 12 and the through-hole 21 may be considered to affect the driving of the pin electrode 10. However, as described above, this clearance is very small, so that the amount of gas leak from the variable pressure gas chamber 30 through this clearance. As a result, the pressure fluctuation in the pressure variable gas chamber 30 becomes extremely small. As a result, this clearance hardly affects the driving of the pin electrode 10. The driving of the pin electrode 10 can be easily realized by using an elastic tool such as a spring or rubber in addition to the pressure variable gas chamber.

  Further, since the pin support 20 serves as a power source or heat source for the pin electrode 10, a material having a conductivity and thermal conductivity equal to or higher than that of the pin electrode 10 is preferable.

  Further, the shape of the pin support 20 may be a flat plate or a composite shape having a curved surface.

The pressure variable gas chamber 30 includes an inner space 31 for storing gas, a channel 32 serving as a gas flow path, and a gas port 33 connected to an external high-pressure gas source (compressor) or a (vacuum) pump. The pressure of the inner space 31 is adjusted by supplying or exhausting gas through the channel 32. Here, the pressure P _in of the inner space 31 is higher than the outside air P _out, the pressure gradient at the inlet and outlet of the through hole 21 is a pin electrode 10 occurs relatively displaced downwardly pushed down by the gas pressure of the inner space 31 It will be. On the other hand, when the pressure Pin _in the inner space 31 is lower than the outside air _Pout , a pressure gradient opposite to that occurs, and the pin electrode 10 is pushed up by the outside air and relatively displaced upward. As described above, the pin electrode 10 can be displaced relative to the pin support 20 by adjusting the pressure of the inner space 31. Further, by adjusting the pressure of the inner space 31 in a state where the pin electrode 10 is in contact with the food material, it is possible to change the pressure at which the pin electrode 10 is in contact with the food material. Therefore, by adjusting the pressure in the inner space 31 with the pin electrode 10 in contact with the food material, the food material can be heated and held by the plurality of pin electrodes 10. Accordingly, by providing the heating electrode 100 with a conveying means, it is possible to stably heat and hold the food by the electrode.

  In addition, about the gas used, they are inert gas, such as clean air and nitrogen, for example.

FIG. 2 is an explanatory view showing an example of heating food by the heating electrode 100 of the present invention.
In this heating example, the food material 51 wrapped in the packaging material 50 as a material to be heated is heated and held by the heating electrodes 100 and 100 arranged vertically (in the vertical direction), and the position between the electrode plates is determined. In this state, it is conveyed by a conveying means (not shown) while being dielectrically heated.

The heating proceeds, the load and if the impedance mismatch of the high-frequency power source occurs, the load by changing the electrode plates distance load adjustment electrodes 40, 40 by the position changing mechanism 42 impedance Z _L and the high frequency power source Match impedance Z _S.

  For adjusting the pressure of the pressure variable gas chamber 30, for example, the compressor 34 and the vacuum pump 35 are coupled to the pressure variable gas chamber 30 via the three-way valve 36, and in the case of pressurization, the pressure is reduced by switching the three-way valve to the compressor 34 side. In this case, the three-way valve is switched to the vacuum pump 35 side.

  Moreover, the frequency of the high frequency power supply 60 is, for example, several KHz to several hundred MHz or 3 MHz to 100 MHz.

  The packaging material 50 is made of, for example, a resin such as PE (polyethylene), PP (polypropylene), or PET (polyethylene terephthalate), a metal such as iron or aluminum, paper, glass, a composite material composed of a combination thereof, or the like. The packaging form is not particularly specified such as a film, a tray, or a cup-shaped container. These containers may be subjected to various surface treatments such as paint and vapor deposition treatment.

  In this heating example, the dielectric heating example using the two heating electrodes 100 and 100 has been described. However, the present invention is not limited to this, and dielectric heating by a combination of the heating electrode 100 and a normal plate electrode may be used. Further, the arrangement of the electrodes may be not only in the vertical direction but also in the horizontal direction.

FIG. 3 is an explanatory cross-sectional view of a main part showing the pin support 20 according to the first embodiment.
In the pin support 20, a water channel 22 through which temperature adjusting water (hereinafter referred to as “temperature-controlled water”) flows vertically passes between the through holes 21. Accordingly, by flowing the temperature-controlled water while the pin electrode 10 is in contact with the food material, heat exchange is performed between the temperature-controlled water and the pin electrode 10, and at the same time, between the pin electrode 10 and the food material. However, since heat exchange is performed, the surface of the food is indirectly heated or cooled as a result. Therefore, hot water is flown as temperature control water in the case of poor heating where the temperature rise is slow, and conversely, cooling water is flowed as temperature control water in the case of overheating where the temperature rise is steep and likely to exceed the target temperature. This makes it possible to control the temperature of food with high accuracy. Thus, by forming the water channel 22 inside the pin support base 20 and flowing the temperature-controlled water, it is possible to control the temperature more efficiently for the food than to air-condition the entire atmosphere. In addition, it is possible to finely adjust the heating temperature for foods that are difficult to adjust by adjusting the frequency and output of the high-frequency power supply 60.

FIG. 4 is an explanatory diagram illustrating a heating method using the heating electrodes 100 and 100 according to the second embodiment. For convenience of explanation, only the pin electrode 10 and the pin support base 20 are drawn, and the other components are omitted.
The heating electrodes are arranged horizontally opposite so that the axial direction of the pin electrode 10 is parallel to the conveying surface of the conveyor C and perpendicular to the conveying direction. Therefore, the food material 51 passes through between the heating pin electrodes while being conveyed by the conveyor C, and is thus subjected to heat sterilization by receiving dielectric heating from the pin electrode 10. In addition, the conveyor C may be stopped for a certain period of time, and the food material 51 may be subjected to heat sterilization by intensively receiving dielectric heating.

FIG. 5 is an explanatory cross-sectional view of a main part showing the heating electrode 200 according to the third embodiment.
The heating electrode 200 includes a cover 52 that suitably protects the pins from contamination due to food contact, steam generated from the food during heating of the food, or corrosion due to the atmospheric environment. The material of the cover 52 is not particularly limited as long as it is flexible and does not impair the pin operation. For example, silicon rubber or fluororubber having a thickness of about 0.3 mm to 5 mm, a thickness of 0.05 mm to 0.00 mm. It is a thermoplastic resin film such as PP, PE, and PET of about 2 mm, or a composite material thereof, and may be a conductive metal foil or conductive foil such as aluminum, copper, carbon, titanium, or platinum. The configuration other than the above is the same as that of the heating electrode 100.

FIG. 6 is an explanatory diagram showing a method of heating food using the heating electrode 200.
This heating method is a heating method in the case where the material to be heated is the food material 51 filled in a container 53 such as a tray or a cup in an unsealed state. One of the electrodes is a heating electrode 200 that is arranged on the upper side and suitably follows the uneven shape of the food material 51 to heat the food material 51, and the other is a concave shape 300a that is arranged on the lower side and molds the bottom shape of the container 53. This is a heating electrode 300 for heating the food 51. Further, the heating electrode 300 is obtained by applying a Teflon (registered trademark) coat, a dicron coat, an electroless nickel plating, etc. as a highly corrosion-resistant surface treatment to an aluminum material processed into a concave shape obtained by shaping the bottom shape of the container 53. In addition, a conductive material such as copper, carbon, titanium, or platinum may be used.

FIG. 7 is an explanatory diagram illustrating a heating method of food using the heating electrode 400 according to the fifth embodiment.
In this heating method, the food 51 wrapped in the packaging material 50 is heated by the heating electrodes 400 and 100 (in the present embodiment, fixed and the position variable mechanism 42 is removed) arranged to face each other in the vertical direction. Dielectric heating is performed in a state of being held and positioned. The heating electrode 400 is a movable electrode, and a variable position mechanism 42 ′ is provided in the variable pressure gas chamber 30 so that the pin support 20 ′ also functions as a load adjustment electrode. 'By pin support 20' the position changing mechanism 42 is relatively displaced in independently of the driving of the pin electrodes 10 relative to the other pin support table 20, matching the impedance Z _L and the high-frequency power source impedance Z _S of the load It becomes possible to make it. The configuration other than the above is the same as that of the heating electrode 100.

  Thus, even if the load adjusting electrode 40 is not separately provided for the heating electrode, for example, by using one heating electrode as a movable electrode and the other heating electrode as a fixed electrode, the pin electrode 10 can be electrically connected to the material to be heated. And / or impedance matching between the load and the high frequency power supply can be achieved without affecting the thermal action.

FIG. 8 is an explanatory cross-sectional view of a main part showing a heating electrode 500 according to the sixth embodiment.
In the heating electrode 500, an electrode that exerts an electrical or thermal action on the heated material while holding the heated material together with the other electrode (not shown) facing each other is constituted by the plate electrode 11 ′. And is driven in the axial direction by the pressure variable gas chamber 30. Similar to the heating electrode 100, the load adjustment electrode 40 can be independently displaced with respect to the plate electrode 11 ′ by the position variable mechanism. Therefore, as in the case of the heating electrodes 100, 200, and 400, when the plate electrode 11 ′ holds the material to be heated and exerts an electrical action and / or a thermal action, the plate electrode 11 ′ has a resistance to the material to be heated. The impedance of the load and the high frequency power source can be matched without affecting the electrical and / or thermal effects.

  Further, similarly to the heating electrode 200, a cover 52 may be provided for the heating electrode 500.

FIG. 9 is an explanatory diagram illustrating the heating electrode 600 according to the seventh embodiment. FIG. 9A is a plan view, and FIG. 9B is a cross-sectional view taken along line AA.
In this heating electrode 600, an electrode that electrically and / or thermally acts on the food 51 that is a material to be heated forms a shape following electrode 11 ″ that partially fits to the outer peripheral surface of the body portion of the container 53. Therefore, the form for heating the food material 51 is a split-type heating form that is sandwiched from both sides by the shape following electrodes 11 ″ and 11 ″ via the insulating member 70. Also, like the heating electrode 100, a load is applied. Since the adjustment electrode 40 can be independently displaced with respect to the shape following electrode 11 "by the load adjustment drive shaft 42a, the electric action and / or the thermal action of the shape following electrode 11" on the material to be heated is affected. The impedance of the load and the high-frequency power source can be matched without affecting the other components, which are not shown in the figure, similar to those of the heating electrodes 100, 200, 400, 500. is there.

  The heating electrode of the present invention and the heating method of a material to be heated using the heating electrode can be suitably applied particularly to heating of an irregular shaped food material.

DESCRIPTION OF SYMBOLS 10 Pin electrode 11 Pin head 12 Rod 13 Pin cap 20 Pin support 21 Through hole 30 Pressure variable gas chamber 31 Inner space 32 Channel 33 Gas port 34 Compressor 35 Vacuum pump 36 Three-way valve 40 Load adjustment electrode 42 Position variable mechanism 52 Cover 100 , 200, 300, 400, 500, 600 Heating electrode

Claims (5)

  A heating electrode for holding and heating a material to be heated that is disposed opposite to the heating electrode, and includes a holding electrode unit that holds the material to be heated, and a load adjustment unit that is electrically connected to the holding electrode unit and can be independently displaced. A heating electrode characterized by that.   The heating electrode according to claim 1, wherein the holding electrode portion and the load adjusting portion are integrated.   The heating electrode according to claim 1 or 2, wherein the holding electrode portion follows the shape of the material to be heated.   The heating electrode according to claim 3, wherein the holding electrode portion is a pin electrode. A heating method for heating a material to be heated by a heating electrode composed of a holding electrode unit for holding the material to be heated and a load adjusting unit for matching impedance,
A method for heating a material to be heated, wherein the impedance matching is achieved by separately displacing the load adjusting unit with respect to the holding electrode unit while holding the material to be heated by the holding electrode unit. .

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