JPS61268920A - Microwave heater - Google Patents

Abstract

PURPOSE:To enable a heating condition of heated item to be controlled uniformly irrespective of variation in power supply voltage by a method wherein the power supply voltage is sensed and a timer setting time is corrected in response to the sensed power supply voltage. CONSTITUTION:A voltage sensor 10 for use in sensing a power supply voltage is provided and its sensed voltage E is inputted into a time calculation means 11. A memory 12 connected to the time calculation means 11 stores a relation between the power supply voltage E and a heating output W at the heating part 35 in advance, the time calculation means 11 reads the heating output W corresponding to the sensed power supply voltage E from the memory 12 and carries out the calculation for correcting the set time (t) set in a timer 31 by the time setting means 30 in an increasing or decreasing direction in response to the increased or decreased heating output W. With this arrangement, even if the power supply voltage E is varied, it is controlled so that a total heating energy becomes a complete constant value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a high-frequency heating device equipped with a timer that regulates the heating time of a heating section according to a set time that is preset by a time setting means.

[Technical background of the invention and its problems]

Although there are various types of high-frequency heating devices of this type, the following explanation will be given using a heating device known as a microwave oven in the field of home appliances as an example.

In the microwave oven, as shown in FIG.
By setting the start switch 33 on in advance, the N source 34 supplies power to the heating unit 35, which has a magnetron as its main component, and outputs the desired high-frequency heating output to heat the object to be heated (not shown). Heat. After the start of heating, when the set time is reached, the timer 31 operates, ie, times up, and the contacts 32 are opened to end the heating.

In such a high-frequency heating device, an increase or decrease in the voltage E of the power source 34 directly leads to an increase or decrease in the output W of the heating section 35, as shown in FIG. 4(a). On the other hand, since the set time t of the timer 31 is constant regardless of fluctuations in the power supply voltage E as shown in FIG. 3(b), the integral value S of the output W within the set time corresponding to the total heating energy Same figure (C)
As shown in , it increases or decreases according to fluctuations in the power supply voltage E. It is obvious that when the power supply voltage E remains at a certain value within the set time and does not change substantially, the output integral value S is equal to the product of the voltage value at the beginning of heating and the set time. . The set time t is determined so that the total heating energy reaches a predetermined value on the premise that the power supply voltage E is maintained at approximately the rated value, and it changes as shown in Figure 4 (C). If this happens, the heating state of the object to be heated, for example, the quality of cooking in a microwave oven, will be different from what was originally planned.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a high-frequency heating device that can control the heating state of a heated object to be constant regardless of fluctuations in power supply voltage.

(Summary of the Invention) In order to achieve the above object, the present invention detects the electric WA voltage, and detects the integrated value of the heating section so that it almost matches the product of the rated heating output of the heating section and the set time. The present invention is characterized in that the set time of the timer is adjusted according to the power supply voltage.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention.

Components that are the same as or correspond to those in FIG. 3 are given the same reference numerals. In the device shown in Figure 1, the electric current mN
A voltage detector 10 for detecting voltage is provided, and the detected voltage E is taken into a time calculation means 11 consisting of, for example, a central processing unit of a microcomputer. A memory 12 is connected to this time calculation means 11. The memory 12 stores in advance the relationship between the power supply voltage E and the heating output W of the heating unit 35, and the time calculation means 11 stores the relationship between the power supply voltage E and the heating output W of the heating unit 35, and the time calculation means 11
The heating output W corresponding to is read from the memory 12, and according to the increase/decrease in the heating output W, a calculation is made to correct the set time t set in the timer 31 by the time setting means 30 in the direction of decreasing or increasing. That is, time calculation means 1
1, when the heating output W changes by a factor of (1+a), the set time t is corrected to become a factor of (1+a)-'. To achieve this, there are two possible methods: modifying the timer 31 from time to time, and modifying the final time-up operation time.

It is assumed that the timer 31 is a pulse counter type built in the aforementioned microcomputer.

According to the first time correction method, the repetition frequency of the counting pulse input to the timer 31 is changed from moment to moment (1+
a) Time correction means 13 so that the total heating energy finally reaches a predetermined value by amending the repetition period of the counting pulse by a factor of (1+a).
Make time corrections via . According to the second time correction method, the heating output W read from the memory 12 is integrally calculated, and the integral value is the rated output of the heating section 35 (heating output when the power supply voltage is at the rated value) and the time setting means 30 When the product is equal to the set time, the timer 31 is caused to perform a time-up operation via the time correction means 13. The same heating effect can be obtained by either method.

According to the present invention, as shown in FIG. 2(a), attention is paid to the fact that the heating output W also changes as the power supply voltage E changes, and as shown in FIG. By adding to the set time t according to the fluctuation, the output integral value S, that is, the total heating energy, is kept at a constant value of 100% with no excess or deficiency, even if the power supply voltage E fluctuates as shown in (C). controlled by.

(Effects of the Invention) As described above, according to the present invention, even if the power supply voltage fluctuates and the heating output fluctuates, the heating time is automatically corrected to always achieve a constant heating effect corresponding to the set time. be able to.

[Brief explanation of drawings]

- Figure 1 is a block diagram showing one embodiment of the present invention, Figure 2 is a block diagram showing an embodiment of the present invention.
Figures (a), (b), and (c) are characteristic diagrams showing how the heating output, set time, and output integral value change when the power supply voltage fluctuates in the device shown in Figure 1, and Figure 3 shows the characteristics of the conventional device. Block diagram of the high-frequency heating device, FIGS. 4(a) and (b). (c) shows Fig. 2 (a) and (b) in the apparatus shown in Fig. 3.
, is a characteristic diagram similar to (c). 10... Voltage detector, 11... Time calculation means, 12
...Memory, 13...Time correction means, 30...Time setting means, 31...Timer, 32...Timer contact, 33...Start switch, 34...Power supply, 35
...Heating section. Applicant's representative Kiyoshi Inomata Figure 1, 92 3rd prisoner

Claims (1)

[Claims] 1. A high-frequency heating device equipped with a timer that regulates heating time by the heating section according to a set time preset by a time setting means, comprising: a voltage detector that detects a power supply voltage; a time period for correcting the set time of the timer in accordance with the power supply voltage detected by the voltage detector so that the integral value of the heating output approximately matches the product of the rated heating output of the heating section and the time set by the time setting means; A high-frequency heating device characterized by being provided with a correction means. 2. The timer comprises a pulse counter, the time setting means comprises means for setting an operation count value of the pulse counter, and the time correction means adjusts the input for the pulse counter according to the power supply voltage. 2. The high-frequency heating device according to claim 1, further comprising means for changing the repetition period of the pulse. 3. The timer comprises a pulse counter, the time setting means comprises means for setting an operation count value of the pulse counter, and the time correction means adjusts the operation count of the pulse counter according to the power supply voltage. 2. The high-frequency heating device according to claim 1, further comprising means for increasing and decreasing the value. 4. The time correction means reads a memory storing the relationship between the power supply voltage and the heating output by the heating section, and reads from the memory the heating output corresponding to the power supply voltage detected by the voltage detector; 3. The high-frequency heating apparatus according to claim 2, further comprising arithmetic processing means for calculating the set time according to the heating output. 5. The high-frequency heating device according to any one of claims 1 to 4, wherein the heating section includes a magnetron, and the set time corresponds to a cooking time.