JPS63223433A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To prevent high-frequency energies from leaking outward by allowing at least one turn of coil-shaped lead wires to exist in a through hole on the wall surface of a heating chamber, and setting the dimension of the lead wire at a value amply smaller than a working waveform. CONSTITUTION:In a heating chamber 1, high frequency energies of a wavelength lambdaare sealed to subject a food to dielectric heating, and the food is externally heated by a sheath heater 3. A coil-shaped lead wire 5 is connected to the end part of the coil-shaped heater wires 6, and at least one turn of the lead wires 5 is positioned in a lead wire support tool 7 of a small dielectric loss inserted into a through hole 4 formed on a wall surface 2 of the heating chamber 1. Therefore, no coaxial transmission line is formed at that part. Further, since the dimension L of the entire part of the lead wire is set as L<<lambda, high- frequency energies do not leak outward from the end part of the sheath heater 3.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a structure for preventing leakage of high-frequency energy from a sheathed heater terminal in a high-frequency heating device that employs a combined heating method using high-frequency energy and radiated heat from a sheathed heater.

Conventional technology Conventionally, a combined heating method has been adopted in which a sheathed heater that penetrates the wall of the heating chamber is installed in the heating chamber to dielectrically heat the food by introducing high-frequency energy, and the food is externally heated using these heating sources. Often seen in high frequency heating devices.

Problems to be Solved by the Invention However, the terminal of the conventional sheathed heater that penetrates the wall of the heating chamber is a rod-shaped terminal connected to the terminal of the sheathed heater, a central conductor, and a coaxial wire that can be considered as the outer conductor or the wall of the heating chamber. Due to the formation of a transmission line, high frequency energy leaks to the outside of the heating chamber during cooking.
As disclosed in Japanese Patent No. 88690, there is a structure in which a choke structure is formed to form a structure for preventing leakage of high frequency energy.

However, with such a configuration, there is a problem that not only the structure is complicated but also a sufficient sealing effect cannot be obtained.

Means for Solving the Problems The present invention has been made to solve the above problems, and includes a coiled heater wire made of a small resistance member at the end of a coiled heater wire of a sheathed heater installed in a heating chamber. At least one lead wire is connected to the lead wire support, which is made of a heat resistant member with a small dielectric loss and is inserted into a through hole drilled in the wall of the heating chamber with a gap between the pitches. In addition, the dimension of the coiled lead wire located on the outside of the heating chamber from the inside of the wall surface is set to be sufficiently smaller than the wavelength used.

By doing this, the heating chamber wall and the coiled lead wire no longer form a coaxial transmission line, and are insulated from the through hole via the lead wire support, and the lead wire has a small resistance. Since the member is a member, temperature rise within the through hole drilled in the wall surface is also suppressed.

Example An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1 showing the configuration of the embodiment, reference numeral 1 denotes a box-shaped heating chamber made of a metal plate, which confines high-frequency energy and dielectrically heats the food placed inside. Reference numeral 2 denotes a wall surface of the heating chamber 1, through which a sheathed heater 3 is provided at the upper part of the heating chamber 1 for externally heating the food. A coiled lead wire 4 is a good conductor made of a material with low resistance loss, which is connected to the end portion of the coiled heater wire 6 in the sheathed heater 3 passing through the wall surface 2 through a through hole drilled in the wall surface 2. This is a portion into which a lead wire support 7 made of a material having high heat resistance and low dielectric loss, such as ceramics, is inserted. At least one turn of the lead wire 5 is located inside the lead wire support 7 and is provided from the inside of the wall surface 2 to the outside of the heating chamber l.The overall dimensions of the lead wire 5 are as follows: When the length of one roll is n and the @number is nL〈〈λ
The sheathed heater 3 is installed in the heating chamber 1 in such a manner. This sheathed heater 3 has a metal outer conductor 8
A coiled heater wire 6 is buried in an insulator 9 filled inside the heater wire 6, and a coiled lead wire 5 formed of a good electrical conductor for supplying current is provided at the end of the heater wire 6. are connected by welding or the like, and a terminal 10 is provided on the opposite side of the lead wire 5 to the heater wire 6.

Next, the operation of the above configuration will be explained.

When high-frequency energy is introduced into the heating chamber 1 to dielectrically heat food, the terminal of the sheathed heater 3 that penetrates the wall surface 2 has at least one turn of the coiled lead wire 5 in the through hole 4, so Such a coaxial transmission line is not formed in this part.

Moreover, since the overall dimension of the lead wire 5 provided from the inside of the wall surface 2 to the outside of the heating chamber l is as described above, according to microwave theory, it is necessary to Since there is no high frequency energy that travels to the outside, the high frequency energy that leaks to the outside from the sheathed heater 3 terminal is significantly lower than the standard value, and there is almost no high frequency energy that leaks.

Furthermore, the lead wire 5 penetrating through the wall surface 2 is reinforced and insulated so that it is inserted into a lead wire support 7 inserted into a through hole 4 formed in the wall surface 2, and the lead wire 5 is Since it is made of a good conductor, it does not generate heat, and the temperature rise inside the through hole 4 is suppressed to a low level.

Effects of the Invention As described above, according to the present invention, the portion of the sheathed heater that penetrates the heating chamber wall surface is penetrated by a coiled lead wire made of a good conductor and connected to the end portion of the heater wire of the sheathed heater, and at least the lead wire is One turn of the lead wire is located in the through hole through which it passes, and the overall dimensions of the lead wire, which is located penetrating from the inside of the heating chamber wall surface to the outside of the heating chamber, are sufficiently small for the wavelength used. Therefore, there is no high-frequency energy leaking to the outside from the terminal part of this sheathed heater, and it is possible to prevent high-frequency energy from leaking to the outside without forming a complicated choke structure like in the past, and to create a simple and reliable seal. You can get some effect.

Further, by providing a lead wire support around the lead wire passing through one through hole, the lead wire is insulated and reinforced, and a more stable sealing effect can be obtained.

Furthermore, since the lead wire is made of a good conductor with low resistance loss, it is possible to suppress the temperature rise inside the through hole, which prevents thermal deformation in this area, resulting in a more stable sealing effect. It is possible to provide a high-frequency heating device that can obtain the following results.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a main part of a sheathed heater terminal portion of a high-frequency heating device showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Heating chamber, 2... Wall surface, 3... Sheathed heater, 4... Through hole, 5... Coiled lead wire, 6... Coiled heater wire, 7... Lead Line support.

Claims (1)

[Claims] A sheathed heater (3) having a built-in coiled heater wire (6) is provided in a metal heating chamber (1) that dielectrically heats food by introducing high frequency energy, the heating chamber (1) A through hole (4) is bored in the wall surface (2) of the hole, and a lead wire support (7) made of a heat resistant material with low dielectric loss is inserted into the through hole (4). A coiled lead wire (5) made of a small resistance member whose windings are located in the lead wire support (7) and whose pitches are spaced apart is connected to an end portion of the coiled heater wire (6), and , heating chamber (1) from inside the wall surface (2).
) A high-frequency heating device characterized in that the dimensions of the lead wire (5) located on the outside are sufficiently smaller than the wavelength used.