JPS6350838B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electric heating device in a high frequency heating device incorporating an electric heating device.

Conventional Structure and Problems When an electric heating device is incorporated into a high-frequency heating device, it becomes a problem to prevent leakage of radio waves to the outside from the mounting portion of the heating chamber.

Conventionally, a cylindrical attenuator was installed on the wall of the heating chamber to prevent wave leakage. The size of this opening is determined by the size of the insulator or protective tube that thermally and electrically protects and insulates the heater. When the size of the heater terminal is small, the radio waves propagating on the heater wire or the heater terminal may leak to the outside without being attenuated by the attenuator.

For example, as shown in FIG. 1, in the case of a heater device in which a coil heater 2 is built into a protective tube 1 made of quartz glass or ceramic, the outer diameter of the insulator 3 that insulates the protective tube 1 and its ends is is determined by the diameter of the coil of the coil heater 2. For the leader wire at the end of the heater, the wire of the coil may be used as is, or a plate-shaped terminal 4 made of a conductive material may be used inside the protective tube 1. It is common to connect this to the insulator 3 and extend it to the outside by passing through the center of the insulator 3.

The through opening of the choke attenuator 5 is determined by the size of the insulator 3, and the size of the terminal 4 is smaller than the outer diameter of the insulator 3, so that the radio waves transmitted through the terminal 4 are There was a drawback that the water leaked out without being attenuated by the choke attenuator 5. On the other hand, it is necessary to hold the protective tube 1 coaxially with the insulator 3, and it is necessary to reduce the size of the insulator 3 due to the work of inserting it from the outside of the heating chamber into the inside and attaching the heater device. Due to the limitations, it has been difficult to realize effective dimensions for demonstrating the effect of the chiyork attenuator.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide a terminal structure that reduces radio wave leakage from the mounting end of a heater.

Composition of the Invention In order to achieve the above object, the heater terminal of the present invention forms a cylindrical part with a size as close as possible to the inner diameter of the through opening of the choke attenuator, and closes one end of the cylindrical part to prevent wave leakage. The path is limited to the gap between the inner cylinder of the chiyoke and the outer cylinder of the terminal, so that the chiyoke attenuator can be effectively used, which has the effect of significantly reducing leakage waves from the heater mounting end.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

In FIG. 2, 6 is a heating chamber, and a tubular heater 7 is attached to penetrate the wall of the heating chamber. A chiyoke attenuator 8 is provided at both ends inside the wall surface.
Note that 9 is a high frequency oscillation device such as a magnetron, and 10 is a waveguide that guides high frequency waves into the heating chamber.

In FIG. 3, 11 is a heater protection tube made of right-handed glass or heat-resistant ceramic, 12 is an insulator, 13 is a coil heater, and 14 is a heater terminal. Since the protection tube 11 and the insulator 12 have approximately the same outer diameter and are coaxial, the size of the through hole of the yoke attenuator 8 through which they pass is approximately equal to the outer diameter of the protection tube 11. terminal 14
The coil heater 13 has a cylindrical portion 14a, the outer diameter of which is large enough to be inserted into the inner diameter of the protection tube 11, and a plate-like protrusion 14b extending in the longitudinal direction.
The lead wires are connected by spot welding, etc. The other end 14c is closed, and wiring is provided on this end surface. The cutout groove 14d is used in combination with a small protrusion provided on the inner wall of the insulator 12 to prevent the terminal 14 from slipping out from the insulator 12. The inner diameter of the insulator 12 is the same as the outer diameter of the cylindrical portion 14a of the terminal 14, and therefore the inner diameter and outer diameter of the protective tube 11 are the same.

FIG. 5 and FIG. 6 show another embodiment, in which the terminal 15 has a hollow cylindrical portion 15a and plate-like protrusions 15b and 15c at both ends. One protrusion 1
5b is a connecting portion of the lead wire of the coil heater 13 as in the first embodiment. After the other protruding piece 15c passes through a hole provided in the insulator 16, it is bent in a direction to close the cylindrical part 15a, as shown by the broken line in FIG.

7 and 8 show still another embodiment, in which the terminal 17 has a cylindrical shape with one end closed, the closed end surface 17b faces the inside of the heating chamber, and the heater coil 13 is located in the center. It has a small hole for passing a leader wire through and connecting by welding or the like. Therefore, the cylindrical portion 17a has an opening on the outside and a plate-like protrusion 17c for external wiring at one end.
Note that the cut-and-raise claw 17d is for preventing the protruding piece 17c from coming off after passing through the insulator 18.

Heater terminals 14, 15, 1 with the above configuration
7 are all cylindrical portions 14a, 15a, 1
7a is arranged so as to overlap the inner cylindrical portion of the chiyoke attenuator 8, and the protection tube 11 and each of the insulators 12, 16, 18 can be inserted into the inner cylindrical portion and held coaxially. . In other words, a gap corresponding to the thickness of the protective tube 11 becomes a space through which high-frequency waves leak, and the function of the choke attenuator 8 can be effectively utilized.

The cylindrical terminal with one end closed reflects the high frequency waves passing through it, regardless of the size of the heater through-hole of the choke attenuator 8. The yoke attenuator 8 is provided with an opening 8a for introducing high frequency waves passing through the through hole, and the cylindrical portions 14a, 15a, 17a of the terminal are arranged to cover this portion. Furthermore, if the terminal protrudes too far from the wall surface of the heating chamber, it acts as a radiation antenna, resulting in a problem of increased wave leakage. Therefore, the terminal is mounted near the outside of the York attenuator 8.

As described above, this embodiment has the effect that leakage can be prevented regardless of the size of the heater penetration opening of the choke attenuator 8.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

1. Even if the outer diameter of the heater becomes large when it passes through the attenuator, the cylindrical terminal with a closed end reflects the high frequency waves that try to pass through the through hole, reducing leakage.

2. The terminal can be inserted as a support material in the inner cylinder of the protective tube or insulator, and the space corresponding to the thickness of the protective tube or insulator becomes a waveguide path for high-frequency waves, and this high-frequency wave is sufficiently affected by the attenuation effect of the chi-yoke attenuator. , it is possible to reduce leakage of waves to the outside.

3 The protective tube and insulator can be held coaxially with the terminal cylindrical part as the axis, and the heater device can be completed as a single piece with a uniform outer diameter, which is convenient for packaging and transporting only the heater device, and There are no irregularities on the outside when installing through the chamber, making it easy to work without getting caught.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a conventional heater device, FIG. 2 is a partial cross-sectional view showing the heater device according to an embodiment of the present invention installed in a heating chamber, and FIG. 3 is a partial cross-sectional view of a heater device according to an embodiment of the present invention.
4 is an external perspective view of the terminal in FIG. 3, FIG. 5 is a partial sectional view of the heater device according to the second embodiment of the present invention, and FIG. 6 is a partial sectional view of the heater device according to the second embodiment of the present invention. External perspective view of the terminal in Figure 5, No. 7
The figure shows a partial sectional view of a heater device according to a third embodiment of the present invention, and FIG. 8 shows an external perspective view of the terminal shown in FIG. 7. 8...Chiyoke attenuator, 11...Protection tube, 1
2, 16, 18... Insulator, 13... Heater coil, 14, 15, 17... Heater terminal.

Claims (1)

[Claims] 1. A straight pipe heater provided in a high frequency heating chamber, a terminal to which the wire end of the heater coil is connected is formed into a hollow cylindrical shape with one end closed,
A high-frequency heating device with an electric heating device, in which the closed end of the terminal is arranged near the outside of a through opening for attaching a heater of a chiyoke attenuator provided on a wall surface of a heating chamber. 2. Claims in which the heater terminal has a hollow cylindrical shape, an extension protrusion is provided in a part of the heater terminal, the protrusion is passed through an insulating member, and then the protrusion is bent so as to close the cylinder. The high-frequency heating device with an electric heating device according to item 1. 3 The protective tube of the heater and the insulator at the end have substantially the same outer diameter, and the protective tube and the insulator are held coaxially with the cylindrical portion of the terminal as a common axis. The high-frequency heating device with an electric heating device according to item 1.