JPS63252390A - Radio frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

Conventional technology A conventional high-frequency heating device employs a combined heating method in which a sheathed heater is installed in a heating chamber to introduce high-frequency energy to dielectrically heat foods to externally heat nine foods. This can be seen in the No. 1 gazette, etc.

Problems to be Solved by the Invention According to the above configuration, in the conventional system in which the sheathed heater is provided penetrating through the heating chamber wall surface, the sheathed heater is connected to the central conductor in the portion of the sheathed heater terminal portion that penetrates the heating chamber wall surface. Since the heating chamber wall surface forms a coaxial transmission line that can be regarded as an external conductor, high frequency energy leaks to the outside of the heating chamber, and a choke must be configured to prevent this leakage.

As shown in Japanese Utility Model Application Laid-Open No. 61-88690, this choke structure is not only very complicated, but also has the problem that a sufficient sealing effect cannot be obtained.

Means for Solving the Problems The present invention has been made to eliminate the above-mentioned drawbacks.The present invention has been made to eliminate the above-mentioned drawbacks. The sheathed heater is removed by fixing only the helical heater wire inside the sheathed heater with a heater support provided inside the cylindrical body facing in the opposite direction and passing it through.

Operation With the above-described configuration, the heating chamber wall surface and the spiral heater wire in the sheathed heater that penetrates the wall surface do not form a coaxial transmission path, so that no high frequency energy leaks to the outside. Furthermore, the cylindrical body installed toward the inside of the heating chamber has the same effect as increasing the apparent thickness of the plate, and the spiral heater wire inside the cylindrical body is fixed to a support to make it more stable. Maintain seal performance.

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

The configuration of the embodiment is as shown in FIG.

In the figure, 1 is a heating chamber made of a metal plate, which confines high frequency energy and dielectrically heats food 2. A sheathed heater 4 is provided penetrating the heating chamber wall surface 6 to heat one food item 2 externally.

A heating chamber wall surface 6 through which the sheathed heater 4 penetrates is provided with a cylindrical body 5 that projects toward the inner side of the heating chamber 1. Heating chamber wall 3
The terminal portion of the sheathed heater 4 that penetrates the sheathed heater 4 is formed by removing the sheathed conductor 6 of the sheathed heater 4 located inside the link 5, forming a gravel-like spiral heater wire 7, and forming a heat-resistant wire around the outer periphery of the heater wire 7. Moreover, it is a material with low dielectric loss.

For example, a heater support 8 made of ceramics or the like is provided and fixed within the cylindrical body 5. At least one turn of the heater wire 7 is located inside the cylinder 5, and the entire dimension of the helical heater wire 7 within the height of the cylinder 5 from the inside of the heating chamber wall surface 3 corresponds to the working wavelength λ.
, When the length of one turn of the spiral heater wire 7 and the number of turns are n, then nL((λ), the sheathed heater 4
is fixed in the heating chamber 1. The sheathed heater 4 has a metal jacket conductor 6 and a spiral heater wire 7 inside the sheathed conductor 6.
An insulator 9 is filled between the two, and one end of the heater wire 7 is provided with a terminal 10 for supplying current. The protruding height of the cylinder 5 is such that at least one turn of the spiral heater wire 7 is included.

Next, the operation of this embodiment having the above configuration will be explained.

When high-frequency energy is introduced into the heating chamber 1 to dielectrically heat the food 2, if the conventional sheathed heater 4 is installed through the heating chamber 1, a coaxial transmission path will be formed in the penetration part. Therefore, high frequency energy leaks to the outside of the heating chamber 1. However, in the present invention, the terminal of the sheathed heater 4 that penetrates the heating chamber wall surface 3 is a gravel-like spiral heater wire 7 existing inside the sheathed heater 4. Moreover, the fact that at least one turn of the spiral heater wire 7 is present in the link 5 means that a coaxial transmission path unlike the conventional one is not formed in this portion. Providing the link 5 inside the heating chamber wall surface 3 has the effect that at least one turn or more of the spiral heater wire 7 can be stably installed inside. In addition, according to the microwave theory, radiation is emitted in the axial direction of the sheathed heater 4 under conditions such that the entire dimension of the spiral heater wire 7 within the height of the cylinder 5 from the inside of the heating chamber wall surface 3 to the end surface is nL ((λ). This means that there is no high frequency energy that travels along the sheathed heater 4 toward the outside of the heating chamber 1. This means that the sheathed heater 4 having the above structure
This was also confirmed in an experiment using , and when the above conditions are satisfied, the high frequency energy leaking to the outside from the sheathed heater 4 terminals is significantly lower than the standard value, and almost no high frequency energy leaks. Further, the spiral heater wire 7 passing through the heating chamber wall surface 3 is reinforced by a heater support 8.

Insulated support.

Effects of the Invention As described above, according to the present invention, a cylindrical body is provided on the inner side of the heating chamber surface that penetrates the wall surface of the heating chamber, and the helical heater wire of the sheathed heater is passed through the cylindrical body.

A spiral bead in which at least one turn of the spiral heater wire is located within the cylinder and extends through the cylinder to the wall surface of the heating chamber. The overall dimension of the evening line is.

This is because it is sufficiently small (nL<<λ) relative to the wavelength.

There is no high frequency energy leaking to the outside from this sheathed heater terminal. Therefore, it is possible to prevent external leakage of high frequency energy without forming a complicated choke structure as in the conventional case, and a simple and reliable sealing effect can be obtained. Further, by providing a heater support around the heater wire that passes through the cylinder, it is insulated and reinforced, and a more stable effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a high-frequency heating device showing an embodiment of the present invention. 1...Heating chamber, 3...Heating chamber wall surface. 4... Sheathed heater, 5... Cylinder 4° 6... Sheathed conductor, 7... Spiral heater wire. 8... Heater support.

Claims (1)

[Claims] The sheathed heater (
The heating chamber (1) is attached to the heating chamber wall (3) through which the end of the heating chamber (1) passes through.
) A cylindrical body (5) formed to protrude inward, and a sheathed conductor (6) of the sheathed heater (4) located near the inside of this cylindrical body (5).
) is formed only with a spiral heater wire (7) from which the heater wire (7) is removed, and a heater support (8) made of a material with low dielectric loss and high heat resistance is provided around the outer periphery of the heater wire (7). The heater wire (7) passes through the cylinder (5) without electrical contact, and at least one turn of the spiral heater wire (7) is located inside the cylinder (5) to heat the cylinder. The spiral heater wire (7) inside the cylinder (5) is inserted from the inside of the chamber wall (3).
) The overall dimensions are nL<<λ (where λ is the wavelength used, L is the length of one turn of the spiral heater wire (7), and n is the number of turns of the heater wire (7) located inside the cylinder (5). A high-frequency heating device characterized by having a sheathed heater 4 having a structure that satisfies the following.