JPS5944787A - High 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 (1) Field of the Invention The present invention relates to a high-frequency heating device that heats an object to be heated to a predetermined temperature by supplying a predetermined power to a heating coil.

(2) Conventional technology A high frequency heating device is generally as shown in FIG.

The output of the high frequency oscillator 1 is applied to the heating coil 2.

The temperature of the object to be heated 3 heated by the heating coil 2 is measured by a radiation thermometer 4, and based on the temperature measured by the radiation thermometer 4, the controller 5 adjusts the temperature of the object to be heated 3 to a predetermined value. The control voltage of the high frequency oscillator 1 was controlled to supply a predetermined power to the heating coil 2.

However, in order to heat a large number of objects 3 to be heated, it is necessary to prepare a plurality of high frequency oscillators 1, which poses a problem that the device becomes very expensive.

Therefore, as shown in FIG. 2, if the capacity of the plurality of heating coils for heating the object to be heated is small, the power output of one high-frequency oscillator 1 is constant.

After rectifying this with a plurality of rectifiers 6, two oscillators 7 are driven, and the output of this oscillator 7 is applied to a small heating coil 2, and a heated object 3 is heated by this heating coil 2.
There is a method of measuring the temperature with a radiation thermometer 4, controlling the control voltage El of the oscillator 7 via the controller 5, and controlling the power of the heating coil 2.

However, even with this method, a large rectifier and two oscillators are required, resulting in a complicated and expensive configuration.

For this purpose, as shown in FIG. 3, a plurality of movable iron core transformers 81 and 82 of relatively small capacity are connected to one high-frequency oscillator 1 with a constant power output, and the output is used to control the heating coil 21.
, 22 are heated, and the temperatures of the heated bodies 31 , 32 are measured using radiation thermometers 41 , 42 .
It controlled the iron core of 82 and the power of heating coils 21 and 22.

However, this method is simple to configure.

Although it was cheaper, it had the disadvantage of poor responsiveness.

(3) Each object of the invention: cvB4cy>50(“・2104°°”・
``An object of the present invention is to provide a high-frequency heating device that is fast and can control the power of a plurality of heating coils connected to one high-frequency oscillator.

(4) Embodiment of the Invention FIG. 4 is an explanatory diagram showing an embodiment of the invention, and the same reference numerals as those in FIGS. 1 to 3 indicate the same components.

In the figure, 1 is one high-frequency oscillator, and its output 1 is distributed from a plurality of transformers 91°92 through an output line t.
The voltage is stepped down to 500V. The outputs of the transformers 91 and 92 are separately applied to a plurality of thyristors 101 and 102, respectively.

The heating coils 21 and 22 are driven by these sirisks ioi and 102 to heat the objects to be heated 31 and 32 at high frequency.

Then, the surface temperatures of the heated bodies 31 and 32 are measured with radiation thermometers 41 and 42 without contact, and a plurality of controllers 5
1 and 52, the outputs of the radiation temperatures i141 and 42 are compared with a preset set value to generate an adjustment signal. This adjustment signal causes multiple ignition circuits 111°11
2, the cyrisks 101 and 102 are arranged at a constant period T1.2 as shown in FIG. Frequency division ignition control is performed to control the on time t within 1, and a predetermined power is supplied to each heating coil 21, 22.

In other words, the output of one high-frequency oscillation is distributed and passed through the plurality of thyristors 101 and 102 to the heating element 51,
52, the thyristor 10 is activated by the ignition circuits 111 and 112.
The heating coils 21 and 2 are subjected to frequency division ignition control.
2 to r! [I am trying to supply a constant amount of power.

Therefore, the device has advantages such as low cost and quick response.

In addition, in the above example, the control loop has been explained as having two loops, but it may be larger than that.

The transformers 91 and 92 are provided as necessary and can be omitted. Further, the control of the thermometers 101 and 102 is performed using radiation thermometers 41 and 42 and adjustment g151.5.
2 may be omitted and the setting fltlJ control may be performed manually.

(5) Summary of the Invention As described above, this invention applies the output of one high-frequency oscillator to a heating coil via a plurality of thyristors.
This is a high-frequency heating device that uses a firing circuit to control the firing of a thyristor in frequency division.

(6) Effects of the invention Therefore, compared to the conventional example, the device for controlling the power supplied to a plurality of heating coils is significantly smaller.

It can be simple, inexpensive, and highly reliable. In addition, since 9-minute station ignition control is performed, compared to phase angle control, it does not generate harmonics in the heating coil and is highly efficient. Also, the response is fast and highly accurate heating control is possible, and the practical effect is extremely large 0

[Brief explanation of drawings]

Figures 1, 2, and 3 are configuration explanatory diagrams showing conventional examples;
FIG. 4 is a configuration explanatory diagram showing one embodiment of the present invention, and FIG.
The figure is a waveform diagram for explaining the operation.01...High frequency oscillator,
2,1.22...Heating coil, 101°102
...Thyristor, 111,112...Ignition circuit patent applicant Noboru Chino Seisakusho Co., Ltd. *() 1

Claims (1)

[Claims] 1. One high-frequency oscillator, a plurality of thyristors to which the output of this high-frequency oscillator is applied, and a plurality of heating coils controlled by these thyristors. A high-frequency heating device comprising: a plurality of ignition circuits that perform frequency division ignition control of the thyristor.