JPS60228948A - Heating apparatus - Google Patents

Abstract

PURPOSE:To prevent erroneous operation inducing the early cut-off of heating caused by the rising of an indirect heater, by mounting a timer started when the supply of a current to the indirect heater begins and reserving the supply of a current to a heating apparatus before a predetermined time is counted. CONSTITUTION:In a heating apparatus having a sensor equipped with an indirect heater, a control part has a timer built therein. When heating is delayed until the indirect heater rises but started prior to the elapse of a delay time TD, heating is reserved. About 10min is required before the perfect rising of the indirect heater but the delay time TD is shortened to such a degree that a detection level DELTAR largely receives no influence, for example, 1min degree. Said time is further shortened by introducing a period outputting a microwave but performing no processing of the sensor resistance by the control part, that is, a mask time TM. By this mechanism, the detection time T1 of the sensor prevents the early cut-off of heating caused by erroneous operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating device equipped with a sensor, and more particularly to a configuration for preventing malfunctions when an indirect heater starts up.

Conventional configuration and its problems A heating device that automatically ends heating using a sensor is
In recent years, it has come into widespread practical use.

For example, this applies to automatic microwave ovens, and the most commonly used sensor is a gas sensor equipped with an indirect heater. The absolute humidity sensor Neo Humiceram manufactured by Matsushita and the gas sensor manufactured by Figaro have been put into practical use, and these sensors indirectly heat the sensor chip to a predetermined temperature using an indirect heater, and remove the water vapor generated from the heated object. Demonstrates desired detection characteristics for various gases.

Now, in a gas sensor equipped with such an indirect heater, power supply to the indirect heater generally starts at the same time as plug-in, but it takes several minutes for it to start up, as shown in FIG. At this time, the resistance of the sensor chip decreases as the temperature of the indirect heater increases, as shown in FIG. 4, and eventually stabilizes.

On the other hand, sensor resistance is reduced by steam or gas. When an object to be heated is heated, it usually changes as shown in FIG. 5A, and by detecting the amount of change ΔR, heating can be automatically terminated.

At this time, the heating time becomes T1. However, if heating is started immediately after plug-in, before the temperature of the indirect heater has risen sufficiently, as shown in Figure 6B, the temperature of the heater will rise before steam or gas is generated from the heated object. The sensor resistance changes by more than ΔR due to a decrease in sensor resistance.

Therefore, since the device apparently behaves as if steam or gas had been generated, heating ends erroneously at time T2, resulting in premature shutdown.

In this way, in a gas sensor equipped with a conventional indirect heater, if heating is started before the indirect heater starts up,
There has been a problem in that heating ends by mistake before the object to be heated is heated.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a heating device that can prevent malfunctions such as premature termination of heating due to startup of the indirect heater.

Structure of the Invention In order to achieve the above object, the heating device of the present invention includes a timer means that is started when power supply to the indirect heater is started, and suspends power supply to the heating means until a predetermined time is counted. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a heating device according to the present invention.

A door body 2 is pivotally supported on the front surface of the main body 1 so as to be freely openable and closable, and an operation panel 3 is provided. An auto key 4 is arranged on the operation panel 3 to perform automatic heating using a sensor.

FIG. 2 is an example of a sensor according to the present invention, and shows Neo Humiceram manufactured by Matsushita Corporation. The sensor chip 5 has moisture-sensitive characteristics and is indirectly heated to a predetermined temperature by an indirect heater 6.
Develop the desired sensing characteristics.

The base 7 supports the sensor chip 5 and the indirect heater 6, and the windproof net 8 removes the influence of wind.

Next, the configuration of such a heating device will be explained using FIG. 6.

Commands input from the auto key 4 on the operating spring y3 are decoded by the control section 9.

Then, the control section 9 starts supplying power to the magnetron 11, which is a heating means, via the driver 10.

In the heating chamber 12, an object to be heated 13 is placed on a mounting plate 14 and rotated by a motor 15 to improve uneven heating.

As the heating progresses, steam and gas begin to be generated from the heated object 13. This water vapor is discharged to the outside of the aircraft from an exhaust guide 17 by a fan 16, and a sensor 18
will be placed. Then, it is connected to the control section 9 via the detection circuit 19. The control unit 9 can be realized by a microcomputer.

Now, the control section 9 has a built-in timer means, and performs control as shown in FIG. 7 at the time of plug-in. FIG. 7 (5) shows the change in sensor resistance over time, which is the same as that explained in the conventional example of FIG.

On the other hand, Figure 7 (■) shows the output state of the microwave, and heating is delayed by a timer means that starts counting from the plug-in until the indirect heater starts up. This is the delay time TD, and if heating is started before the TD time has elapsed after plug-in, the heating will be delayed until the delay time TD has elapsed.

It takes about 100 minutes for the indirect heater to fully start up.
If this is used as a delay time, the product quality will be significantly lowered. Therefore, the delay time is shortened to such an extent that the detection level ΔR is not significantly affected. Since 95% or more of the saturation temperature is normally reached in one minute, the delay time may be about one minute. In this embodiment, a mask time TM is introduced to further reduce this time. This is a period in which the microwave is output, but the control unit does not process the sensor resistance.

To complete heating no matter how small the amount of the object to be heated, it takes 30~
It takes 40 seconds to cook. Mask Time TM focuses on this point, and is based on the viewpoint that heating will not end even if the microwave is output while masking the sensor processing for about 20 to 30 seconds. This allows for example TD
= 30 seconds and TM = 30 seconds, it is possible to suppress the total heating time T() from increasing by 1 minute due to the delay to 30 seconds.

By introducing the delay time TD and mask time TM,
(5) As shown in the figure, the sensor detection time T1 is the fifth
It is possible to prevent malfunction and premature disconnection as in the conventional example shown in Figure B.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) It is possible to prevent malfunctions such as premature termination of heating due to startup of the indirect heater immediately after plug-in.

2. In actual use, it is impossible to start heating immediately after plug-in, considering the time required to open and close the door, carry the object to be heated into the heating chamber, select the desired auto key, etc. There are relatively many cases in which more time than the delay time TD is spent on these tasks.

Therefore, in practice, heating time is unlikely to be significantly extended by TD, but even if the user quickly starts heating within the TD time, the present invention can reliably prevent premature cut-off.

■ Delay time TD can be further shortened by introducing mask time TM. Therefore, in practice, it is unlikely that the TD time will extend the heating time.

[Brief explanation of the drawing]

Fig. 1 is a heating device showing an embodiment of the present invention, Fig. 2 is a partial sectional view of a sensor equipped with an indirect heater, Fig. 3 is a rise characteristic diagram of the indirect heater of such a sensor, and Fig. 4 is a Figure 5 is a diagram showing the change in sensor resistance over time during conventional heating, A is normal, B is heating immediately after plug-in, and Figure 6 is a diagram showing the present invention. An example of
FIG. 7 is a block diagram showing the configuration of the heating device shown in FIG. 7, a diagram showing changes in sensor resistance during heating, and FIG. 5...Sensor chip, 6...Indirect heater, 9...Control unit, 11...Heating means, 12...Heating Chamber, 13... Heated object, 18... Sensor. Name of agent Patent attorney Toshio Nakao and 1 Energy saving Figure 1 Figure 2 Figure 3 Figure 4 1+Time (current) Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] A heating chamber in which an object to be heated is placed, a heating means coupled to the heating chamber, a control section for controlling power supply to the heating means, and an indirect heater for detecting a heating state of the object to be heated. and a timer means, and the control unit starts the timer means when power supply to the indirect heater starts, and does not supply power to the heating means until a predetermined time is counted. A heating device configured as follows.