JPS63223425A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To prevent high-frequency energies from leaking outward by setting the diameter of each of heater wires located within the penetrating part of the wall surface of a heating chamber at a value smaller than the diameter of the hole of the penetrating part, but larger than the half of the hole diameter and further setting the dimension of the heater wire at a value sufficiently smaller than a working wavelength. CONSTITUTION:In a heating chamber 1, high-frequency energies having a wavelength designated by lambda a food placed therein is subjected to dielectric heating, and the food is heated externally by a grill heater 4 containing therein coil-shaped heater wires 3 each having a turn diameter (r). The heater wires 3 are supported by heater support tubes 5 made of ceramics and the like, and the terminal end parts of the heater wires 3 are disposed so that at least one turn thereof is located within a penetrating part 6 having a hole diameter R and formed on the wall surface 2. Further, the dimension L of the entire part of the heater wires 3 are set as L<lambda. For this reason, the penetrating part 6 and the heater wires 3 do not constitute a coaxial transmission line, and high-frequency energies advancing toward the outside of the heating chamber 1 along the axial direction of the heater 4 do not exist. Further, the diameter (r) of the turn is set at R/2<r<R thereby to set the amount of high-frequency energies leaking at minimum.

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 heater terminal in a high-frequency heating device that employs a combined heating method that utilizes high-frequency energy and radiated heat from a grill heater.

Conventional technology Conventionally, a heating chamber for dielectrically heating foods by introducing high-frequency energy was equipped with a Krill heater that penetrated the heating chamber wall and had a coiled heater wire built into a support tube made of ceramics, etc. JP-A-13442 adopts a composite heating method that heats food externally using a source.
This can be seen in high-frequency heating devices as described in Publication No. 7.

Problems to be Solved by the Invention However, in the conventional method of providing a creel heater having a coiled heater wire that penetrates the wall surface of the heating chamber, the rod-shaped portion of the heater wire that penetrates the wall surface of the heating chamber is the heater wire. Since it forms a coaxial transmission line that can be regarded as a central conductor, a heating chamber wall, or an external conductor, the heater wire or the part that passes through the heating chamber wall during high-frequency cooking leaks to the outside of the heating chamber wall. The yoke structure is not only complicated, but also has problems in that it does not provide a sufficient sealing effect.

Means for Solving the Problems The present invention has been made to solve the above problems, and at least one turn of a coiled heater wire having a gap between the pitches of a creel heater provided in the heating chamber is provided in the heating chamber. The heater wire is located within a penetration hole drilled in the wall surface, and the diameter of the heater wire is smaller than the hole in the penetration section, and the diameter is larger than half of the hole diameter, and the heater wire is located inside the wall surface. The dimensions of the coiled heater wire located on the outside of the heating chamber, including the inside of the through-hole, are set to be sufficiently smaller than the wavelength used.

Effect: By doing this, the wall of the heating chamber and the coiled heater wire do not form a coaxial transmission line.

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

In FIG. 1 showing the structure of the embodiment, reference numeral 1 denotes a box-shaped heating chamber, which is composed of a metal plate, and is designed to confine high-frequency energy and dielectrically heat the food placed inside. Reference numeral 2 denotes a wall surface of the heating chamber 1, and a grill heater 4 having a built-in coiled heater wire 3 is provided at the upper part of the heating chamber 1, passing through the wall surface, so as to externally heat the food. Further, the outer periphery of the heater wire 3 is supported by a cylindrical heater support tube 5 made of a material with high heat resistance and excellent heat conduction, such as quartz or ceramics. The part that penetrates the wall surface 2 of the terminal is
At least one turn of the heater wire 3 is located within a through-hole 6 formed in the wall surface 2.

Furthermore, when r is the diameter of the heater wire 3 and R is the diameter of the hole 6 through which the heater wire 3 passes, R/2 < r <
R... has the following relationship, and the overall dimension of the heater wire 3 provided outside the heating chamber 1 including the inside of the penetration part 6 from the inside of the penetration part 6 is nL<λ (where λ is the wavelength used About 12
0 mm, L is the length of one turn of the heater wire 3, and n is the number of turns of the heater wire 3 located inside and outside the wall surface 2. ).

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

When high frequency energy is introduced into the heating chamber l to dielectrically heat food, the heater wire 3 passing through the penetration part 6
The overall dimension of the heater wire 3 provided on the outside of the heating chamber 1 including the inside of the penetration part 6 from the inside of the wall surface 2 such that at least one turn or more is present in the penetration part 6 is such that < nL < λ as described above. Because of these conditions, the penetration part 6 and the heater wire 3 do not constitute a coaxial transmission line, and according to microwave theory, there is no high frequency energy that propagates toward the outside of the heating chamber 1 along the axial direction of the grill heater 4.

Further, when the diameter r of the heater wire 3 is R/2 < r < R, the leakage amount of high frequency energy is the smallest.

Effects of the Invention According to the present invention, as described in 2., a grill heater having a coiled heater wire housed in a heater support tube is passed through a penetration portion drilled in the wall surface of the heating chamber, and at least the heater wire is connected to the grill heater. One turn of the heater wire is located within the penetration part, and the overall dimensions of the heater wire, which is located penetrating from the inside of the heating chamber wall surface to the outside of the heating chamber, are made sufficiently small relative to the wavelength used, and the heater wire is By making the diameter smaller than the hole diameter of the through-hole but larger than half of the hole diameter, there is no high frequency energy leaking to the outside from the grill heater terminal, and a complicated choke structure like the conventional one can be formed. It is possible to provide a high-frequency heating device that can prevent high-frequency energy from leaking to the outside without any problems, and can provide a simple and reliable sealing effect.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of a main part of a terminal portion of a Krill heater of a high-frequency heating device showing an embodiment of the present invention. 1... Heating chamber, 2... Wall surface, 3... Coiled heater wire, 4... Grill heater, 5... Heater support tube, 6... Penetration part.

Claims (1)

[Claims] A grill heater (4) in which a coiled heater wire (3) is built into a heater support tube (5) made of ceramics or the like is installed in a metal heating chamber (1) that heats food by introducing high-frequency energy. The heating chamber (1)
A diameter (r) of the heater wire (3) is formed with a penetration part (6) in the wall surface (2), and at least one turn is located in the penetration part (6), and each pitch is spaced apart. is smaller than the hole diameter (R) of the penetrating portion (6), and the diameter (r) is larger than half of the hole diameter (R), and the penetrating portion is formed from the inside of the wall surface (2). (6) A high-frequency heating device characterized in that the dimensions of the heater wire (3) located outside the heating chamber (1) including the inside thereof are sufficiently smaller than the wavelength used.