JPS6021474B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device that controls the output of a magnetron by intermittent oscillation. It has become common to have a function to control
One of the most effective ways to achieve this function is to turn the magnetron on and off depending on the required microwave output.

In other words, if operated continuously, a magnetron with an output of 600 W can be used for a relatively short period of time, for example, NI of 1 inkstone sand.
If it is intermittent with a cycle such as Akasuna's FF, it will actually be 30
This provides the same heating effect as continuous oscillation with a microwave output of about 0 W. In this case, methods for intermittent oscillation of the magnetron include a method of intermittent the primary input of the transformer that supplies voltage to the magnetron, a method of intermittent the anode voltage on the secondary side of the transformer, a method of intermittent of the heater voltage, etc. . However, in either method, interference electromagnetic waves over a wide band are generated due to the bouncing phenomenon of the contacts of the switch and arc discharge between the contacts when the switch is turned on and off. If this interfering electromagnetic wave occurs only sporadically, such as when the high-frequency heating device starts and ends its use, it will not pose any practical or legal problems, but when performing the above output control, it is necessary to control the intermittent period. Since it is necessary to keep the time short, on the order of seconds, the interfering electromagnetic waves are always emitted from the main body of the high-frequency heating device and propagate to the outside via the power line, causing the above-mentioned damage. Therefore, it is possible to take measures to prevent this by shielding the contacts of the switch or inserting filter circuits before and after the contacts, but they are very expensive and are not practical. isn't it. Therefore, the present invention aims to solve the above-mentioned drawbacks of the conventional filter by housing the switch in a filter box.

0 Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a magnetron that supplies high-frequency electromagnetic waves into a heating chamber (not shown), and the heater voltage and anode voltage of this magnetron 1 are determined by a half-wave voltage doubler circuit 4 consisting of a cotandenser 2 and a diode 3; It is designed to be supplied via a high voltage transformer 5.

Further, a high voltage reed switch 6 is interposed in the heater voltage and anode voltage supply path, and the opening/closing thereof is ON--
The OFF control circuit 7' is configured to be operated by an electromagnet 8 which is connected to the OFF control circuit 7'.

Note that 9 in Figure 1 is a choke coil, and IQ is a feed-through capacitor, and the filter circuit formed by these two blocks interference waves from getting on the power line.

-Figure 2 shows the arrangement of each of the above parts, and la in this figure is a magnetron! This cathode bushing la is covered with a filter box 11 made of a non-magnetic material such as aluminum.

Further, the above-mentioned high voltage reed switch 6 is also housed within the filter box holder 1.

As is clear from this figure, this high-voltage reed switch S utilizes a vacuum switch in which a fixed pole 6b and a movable pole 6c are housed in a glass tube 6a. In the above configuration, when the ONOFF control circuit 7 shown in FIG.
This allows the movable gutter 6c of the high voltage reed switch 6 in FIG.
Then, the fixed pole 6b is electrically disconnected. ``As a result, the output of the magnetron turtle is controlled, but even if interference electromagnetic waves are emitted from the high-voltage reed switch 6 mentioned above during this control, they will be transmitted to the filter box 1.
1 and will never leak outside. Therefore, as in the conventional case, it is possible to prevent the harmful influence of the interference radio waves on the wireless equipment.

3, 7, and 4 show another embodiment of the present invention, in which a high voltage reed switch 6 is used to turn on and off only the anode voltage.

Note that 9' in FIGS. 3 and 4 is a feedthrough capacitor.

In addition, ``In the above two embodiments, the high voltage IJ-do switch 9 was connected and connected by the electromagnet 8, but it may also be connected and connected by a permanent magnet, and furthermore, by using a switch other than the high voltage reed switch g, this It may be interrupted by other means.

As described above, according to the present invention, the interfering electromagnetic waves generated when the switch that controls the output of the magnetron is operated are shielded by the filter box and never leak outside the high-frequency heating device. will not have any adverse effect on wireless equipment.

In addition, since the structure is simply to provide a switch in the filter box that magnetrons have conventionally included, it can be provided at an extremely low cost.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram of a main part of a high-frequency heating device according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of the same device, and FIG.
The figure is a main electrical circuit diagram of a high-frequency heating device according to another embodiment of the present invention, and FIG. 4 is an enlarged sectional view of the main part of the same device. 1... Magnetron la... Cathode pushing, 6...
High voltage reed switch, 8...electromagnet, 10...filter box. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a high-frequency heating device that performs output control by switching on and off the magnetron heater voltage supply line or anode voltage supply line with a switch, the cathode bushing of the magnetron is covered with a filter box, and the above-mentioned opening/closing switch is placed inside the filter box. A high-frequency heating device is provided with an electromagnet or a permanent magnet outside the filter box as an operation means for intermittent operation of the switch from outside the filter box.