JPS5852125B2 - High frequency heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device equipped with a mechanism that detects the temperature of an object to be heated and automatically controls the heating time.

BACKGROUND ART In high-frequency heating devices such as microwave ovens, a method has been devised in which the temperature of the object to be heated is indirectly detected by detecting the temperature of the air discharged from the heating chamber, and the heating time is automatically controlled.

This utilizes the phenomenon that as the object to be heated housed in the heating chamber is heated by high frequency power supplied from a high frequency oscillation tube, the temperature of the air passing through the heating chamber increases.

However, in the above-mentioned conventional high-frequency heating device, an exhaust port for discharging air from the heating chamber is provided on the wall of the heating chamber, so the exhaust port is located far away from the object to be heated, and there is a gap between the object to be heated and the exhaust port. The wind path is wide.

For this reason, the air heated by the object to be heated mixes with cold air that has not been warmed by the object to be heated by the time it reaches the exhaust port, resulting in a decrease in temperature, and eventually the exhaust air (
The temperature rise value of the exhaust gas (hereinafter abbreviated as exhaust gas) is extremely small.

Therefore, it is necessary to detect the degree of heating of the heated object by detecting a slight increase in the exhaust gas temperature, so the accuracy of detecting the temperature of the heated object is poor, making it difficult to properly heat the heated object. It had

An object of the present invention is to provide a high-frequency heating device that eliminates the above-described drawbacks of the conventional technology by increasing the temperature rise value of the exhaust gas of the heating chamber, and that accurately and automatically controls the heating time of the object to be heated. be.

In order to achieve the above object, the present invention provides a pipe in the heating chamber and exhausts the air through the pipe, thereby bringing the exhaust port closer to the object to be heated and increasing the temperature rise value of the exhaust gas.

The present invention will be specifically explained below using the drawings.

FIG. 1 shows an embodiment of a high frequency heating device according to the present invention.

The feature of this embodiment is that a pipe 8 is provided in the heating chamber 1 as shown in FIG. , which increases the temperature rise of the exhaust gas.

The mechanism for automatically controlling heating time will be described below.

In FIG. 1, an object to be heated 3 placed on a saucer 2 in a heating chamber 1 is heated by high frequency power supplied from a high frequency oscillation tube 4. As shown in FIG.

During the heating period, the heating chamber ventilation fan 5 operates, and as a result, the outside air that enters from the high-frequency heating device intake port 6 enters the heating chamber 1 from the heating chamber intake lower, passes around the object to be heated 3, and , passes through a pipe 8 protruding into the heating chamber 1, flows out of the heating chamber 1 from the heating chamber exhaust port 9, and flows out of the high frequency heating device via the exhaust fan 5.

Note that the pipe 8 is desirably made of a material that is non-metallic and has low dielectric loss.

Further, 10 is a high-frequency stirring fan for preventing uneven heating, 18 is a partition plate that partitions the inside of the heating chamber, and 19 is a non-ventilated fan.

In FIG. 1, the temperature of the air taken into the heating chamber 1 is detected by the intake sensor 11, and the temperature of the air discharged from the heating chamber exhaust port 9 via the pipe 8 is detected by the exhaust sensor 12. The temperature of the intake air is approximately constant (approximately equal to the temperature of the outside air) with respect to the heating time, but the temperature of the exhaust air gradually increases due to the hot air of the object to be heated 3.

Since the exhaust gas temperature before the start of heating is approximately equal to the intake air temperature, by detecting the temperature difference between the intake air and the exhaust air, it is possible to know the increase in the exhaust gas temperature during the heating period.

By detecting the increased value of the exhaust gas temperature in this manner, the temperature of the object to be heated 3 is detected.

Then, when this detection signal is applied to the control device 13, when the increase value of the exhaust gas temperature reaches a preset value, the control device 13 controls the power supply device 14 of the high frequency oscillation tube.
The output is cut off, the oscillation of the high frequency oscillation tube 4 is stopped, and the heating is ended.

Next, FIG. 2 shows the case where 100 cc of water is used as the object to be heated 3 and the opening 15 at the tip of the object to be heated 3 and the pipe 8.
The figure shows how the increase in exhaust gas temperature changes depending on the distance l.

It can be seen from FIG. 2 that the smaller l is, that is, the closer the tip opening 15 of the pipe is to the object to be heated 3, the greater the increase in exhaust gas temperature becomes.

This result also shows that if pie and eve are not provided as in the past (
That is, it is clear that the increase in exhaust gas temperature is significantly increased by providing the pipe 8 compared to when g=o).

The reason why the exhaust temperature increases by using the pipe 8 is that the exhaust port is substantially closer to the object to be heated, which makes it easier to concentrate the hot air from the object to be heated, and the pipe 8 forms a narrow air path. This is thought to be because cold air can be prevented from entering while passing through the pipe.

As a result, the accuracy of detecting the temperature of the object to be heated based on the exhaust gas temperature is improved, the object to be heated can be properly heated, and the control device can be simplified and lowered in price.

Next, FIG. 3 is a diagram showing another embodiment of the present invention.

This shows an example in which the pipe 8 is installed horizontally, and also shows how to create an air path that can reduce the number of fans.

When the heating chamber ventilation fan 5 operates, the outside air entering from the high frequency heating device intake port 6 provided at the front of the device enters the heating chamber 1 from the heating chamber intake lower, rotates the high frequency stirring window 10, and passes through the partition plate. 18, the flow flows downward from the door 19 side by stroking the back side of the door 19 to prevent fogging of the non-ventilated door 19, passes around the object to be heated 3, is sucked into the pipe 8, and enters the heating chamber. It flows out of the heating chamber from the exhaust port 9, cools the high frequency oscillation tube 4 via the ventilation fan 5, and flows out of the housing.

The temperature of the exhaust gas is detected in front of the ventilation fan 5.

In this way, according to the embodiment shown in FIG. 3, with one fan,
It is economical because it can rotate the high-frequency stirring fan, prevent the door from fogging up, ventilate the heating chamber, and cool the high-frequency oscillation tube.

The above explanation has been about the method of detecting the temperature rise of the air discharged from the heating chamber, but the mechanism according to the present invention can also be applied to a method of detecting the humidity of the discharged air and controlling the heating time of the object to be heated. has the effect of increasing control accuracy.

This control method based on detection of exhaust humidity is a method in which steam generated from the object to be heated 3 is detected and heating of the object to be heated is stopped.

Now, if we apply the exhaust method using the pipe of this example,
In FIG. 1, as the exhaust port approaches the object to be heated 3, the proportion of steam in the exhaust gas increases significantly compared to the conventional example, and the humidity of the exhaust air becomes high. Detection becomes more accurate.

Note that in this case, the intake sensor 11 is not necessary.

Furthermore, although the above embodiment describes a method for detecting the temperature (or humidity) of the air discharged from the heating chamber, it can also be used to detect the temperature (or humidity) of the air inside the pipe installed in the heating chamber. The effects of the present invention remain unchanged.

In this case, the exhaust sensor is used while being shielded from high frequency power by a high frequency shield having ventilation holes.

In addition, in the above embodiment, the door is a non-ventilated door, but an opening in the door can be used to draw outside air into the heating chamber through the door (i.e., when the door is used as the heating chamber intake port). The present invention is also applicable.

Furthermore, the present invention is also applicable to the case where heating is continued by reducing the high frequency power when the temperature (or humidity) of the exhaust gas reaches a preset value.As described above, according to the present invention, By providing a protruding pipe in the heating chamber and exhausting the air through this pipe, the exhaust port is brought closer to the heated object, so the temperature rise value of the exhaust gas (or the humidity of the exhaust gas) becomes large, and therefore the heated object This not only improves the accuracy of temperature detection and optimizes heating, but also improves the reliability of control performance.
Furthermore, significant effects such as the simplification and cost reduction of the control device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the high-frequency heating device according to the present invention, FIG. 2 is a diagram showing the exhaust temperature increase characteristic for explaining the present invention in detail, and FIG. 3 is a diagram showing an example of the high-frequency heating device according to the present invention. This is an example. 1... Heating chamber, 3... Heated object, 4.
...High frequency oscillation tube, 5...Heating chamber ventilation fan, 8...Pap, 9...Heating chamber exhaust port, 11... ...Intake sensor, 12...
...Exhaust sensor, 13...Control device.

Claims (1)

[Scope of Claims] 1. A mechanism for detecting the temperature of air within the heating chamber or air discharged from the heating chamber in a high-frequency heating device that supplies high-frequency power into a heating chamber housing an object to be heated to heat the object. a mechanism for stopping the supply of the high-frequency power or a mechanism for reducing and continuing the high-frequency power when the temperature of the air reaches a preset value; and a pipe protruding into the heating chamber; A high-frequency heating device characterized in that the heating chamber is evacuated through the heating chamber. 2 A mechanism for detecting the humidity of the air in the heating chamber or air discharged from the heating chamber, and a mechanism for stopping the supply of the high frequency power or reducing the high frequency power when the humidity of the air reaches a preset value. 1. A high-frequency heating device, comprising: a mechanism for continuously heating the heating chamber; and a pipe protruding into the heating chamber, the heating chamber being exhausted through the pipe.