JPH0343676Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a microwave output detection device for displaying microwave output and detecting whether or not the output is a predetermined value in a microwave heating device.

[Prior art]

In a microwave heating device, there is a method using half-wave voltage doubler rectification as a high voltage rectification method for operating a magnetron. As a method of varying the output of this method, an intermittent irradiation method in which the microwave output is periodically turned on and off is often adopted. This is a method of changing the average output per certain period of time without changing the output peak value itself.

The period of turning on and off is determined by taking into consideration the heating time based on the temperature increase of the object to be heated, the rise time of the microwave output, and the life span of the magnetron due to frequent turning on and off.
Usually, heater current is supplied continuously in advance,
When turning high voltage on and off, its rise time is
It takes about 0.2 to 1.0 seconds. Therefore, it is not possible to turn on and off at a cycle shorter than that time.

When displaying the output under these conditions, if the display is done directly using the anode current, even when monitoring the microwave, the output will change between high and low points in an on/off cycle. become.
In other words, when the microwave output is on, it shows 〓high〓,
When it is off, it indicates low.

Therefore, if this anode current is used as it is to display the output, it is not possible to accurately know how many watts the current output is or what percentage of the maximum value it is, and it is difficult to use the anode current for industrial or experimental purposes. In this case, it would be necessary to delicately adjust the microwave output, but this would also be impossible. Furthermore, it is not possible to capture how much energy is currently being consumed. Furthermore, unless you directly look at the anode current, you will not be able to tell if there is a difference between the displayed output and the actual output due to a malfunction or the like.

Therefore, the above-mentioned on/off anode current is
It is conceivable to input the data into a circuit with a large time constant and display it, but this would be insufficient in terms of accuracy.

[Purpose of the invention] The purpose of the invention is that even if the output is determined by turning on and off the anode current as described above,
The purpose is to be able to accurately detect the output.

[Structure of the idea]

To this end, the present invention includes means for counting the number of anode current pulses of the magnetron per unit time, and means for holding the output from the means for the unit time.

〔Example〕

Examples of the present invention will be described below. First, when the magnetron is driven by half-wave voltage doubler rectification, the anode current becomes a pulsating flow as shown in FIG.
Therefore, in this embodiment, the output is detected by counting how many peaks of the pulsating flow appear per unit time. For example, 50 when the output is maximized.
In Hz, 50 pieces appear per second, and similarly 60 pieces appear per second.
At Hz, 60 will appear. Therefore, if you reduce the output and turn on half a cycle per second and turn off the remaining half, the output will be 25 at 50Hz and 30 at 60Hz. In this way, by counting the number of peaks in the pulsating flow waveform per unit time, the output can be detected.

By detecting the average microwave output using the intermittent irradiation method, it is possible to monitor it and make subtle adjustments to the microwave output, and also to know what percentage of the maximum output is currently being output. It is also possible to obtain an estimate of energy consumption. Furthermore, by determining whether an anode current is flowing when the conditions are such that microwaves should be generated, it becomes possible to diagnose failures based on the mode jump of the magnetron. In addition, it is very often necessary to display the microwave output for industrial or experimental microwave equipment.

A detailed explanation will be given below with reference to the drawings. FIG. 2 is a diagram showing one embodiment thereof. Reference numeral 1 denotes a detection section for detecting the anode current of the magnetron, and the waveform signal of the anode current detected there as shown in FIG. 1 is shaped into a rectangular wave by the next waveform shaping circuit 2.
The pulses from this waveform shaping circuit 2 are counted by a counter 3 and held by the next hold circuit 4. Reference numeral 5 denotes an oscillator that oscillates a pulse with a constant period, and inputs it to the counter 3 and the hold circuit 4 as a reset signal.

The counter 3 thus counts the pulses that arrive during the period of the pulses from the oscillator 5. In other words, the number of pulsating anode currents arriving during this period is counted. For example, if the period of the output pulse of the oscillator 5 is 1 second, 50 pulses will be counted at 50 Hz. The hold circuit 4 holds the output value of the counter 3 for the period of the output pulse of the oscillator 1, and holds the new output value when the period of the period has elapsed. A display 6 displays the hold value of the hold circuit 4, that is, the microwave output value.

FIG. 3 is a diagram showing another embodiment in which it is possible to detect an abnormality in the anode current due to a mode jump or the like. In this embodiment, a comparator 7 is provided on the output side of the hold circuit 4, a signal from a numerical indicator 8 is inputted to the comparator 7, and the value of the currently detected microwave output is input to the comparator 7. and the value set with the numerical indicator 8 can be compared.

Therefore, by setting the pulse count value that must be currently detected using the numerical indicator 8, by comparing that value with the currently detected pulse count value, for example, if the latter is low, Anomalies will be detected. This detection result can be displayed on the display 9. For example, when the mode jump of the magnetron occurs, the anode current waveform becomes abnormal and is notified on the display 9.

[Effect of idea]

As described above, the present invention is equipped with means for counting the number of magnetron anode current pulses per unit time and means for holding the output from the means for the unit time. Microwave output can be detected easily and accurately, making it easy to make delicate adjustments to microwave output, check energy consumption, and diagnose failures.

[Brief explanation of the drawing]

FIG. 1 is a waveform diagram of the anode current of the magnetron, FIG. 2 is a block diagram of one embodiment of the output detection device of the present invention, and FIG. 3 is a block diagram of another embodiment. 1... Anode current detection section, 2... Waveform shaping circuit,
3... Counter, 4... Hold circuit, 5... Oscillator, 6... Display, 7... Comparator, 8... Numerical indicator, 9... Display.

Claims (1)

[Claims for Utility Model Registration] (1) A microwave heating device comprising means for counting the number of anode current pulses of a magnetron per unit time, and means for holding the output from the means for the unit time. An output detection device characterized by: (2) The output detection device according to claim 1, wherein the output from the holding means is input to display means. (3) The output detection device according to claim 1, wherein the output from the holding means is compared with a predetermined comparison signal, and the comparison result is displayed.