JPS6016233A - Automatic high frequency heater - Google Patents

Abstract

PURPOSE:To generate sensor signal and at the same time enable to prevent the dew condensation from developing on the inner wall of a chamber by a structure wherein an air flow rate changing device such as damper or the like is provided in an air passage between a supply fan and an outside air discharging part so as to change the air flow rate with a proper timing. CONSTITUTION:A damper is open for a certain fixed period of time ts after the start of heating in order to scavenging for the previous cooking. After that, the damper is closed in order to turn the flow rate of air blasted in a chamber to zero or smaller. A point of detection is determined by comparing the signal S with the minimum value Sm, at the value of which the threshold value equals to the set threshold values DELTASs. The satisfactory heating is established by stopping a magnetron at the point of detection or by controlling heating after the point of detection. Further, when the damper is open at the time when the point of detection is determined, no dew condensation occurs because the high humidity gas in the chamber can be scavenged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a configuration for increasing the sensor reliability of an automatic microwave oven (high frequency heater).

Is the conventional gas sensor or humidity sensor material automatic? 1. ? : r
Many microwave ovens have a duct that scavenges air from inside the oven to the outside, and a magnetron cooling fan is often used to blow the scavenging air. Furthermore, rather than sending all the airflow after magnetron cooling into the refrigerator, a portion of the airflow was sent in a branched manner. This is to reduce the air blow Lit in order to make the sensor signal as large as possible.

On the other hand, there are conditions for scavenging inside the warehouse. There is a minimum air volume that prevents condensation through the window that looks into the inside of the microwave oven and the compartment 17 when steam is generated from the food in the microwave oven as it heats. That means it needs to work.

Therefore, there was a problem in that the sensor signal could not be increased beyond a certain level by restricting the amount of scavenging air (riill11).Especially when using a sensor that detects relative humidity, it is difficult to use a microwave oven in combination with a normal oven. When attempting to detect humidity after cooking in the oven, the temperature inside the oven is high, so the relative humidity often drops and detection is not possible at all, so it is necessary to wait until the temperature inside the oven cools down.

The present invention has a configuration in which an air volume changing device such as a damper is installed in the air path between the blower fan and the outside air exhaust section, and by changing the air volume at an appropriate timing, the sensor signal can be increased and the structure can also prevent rice bran from forming on the interior walls of the refrigerator. This is what makes it possible.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, 1 is a heating chamber, 2 is food, 3 is a plate on which the food is placed, and 4 is a heating wall constituting the heating chamber. 5
, 6 is an opening I provided in the heating chamber wall.

■, 7 is a waveguide for supplying radio waves, 8 is a magnetron, 9 is a blower fan for cooling the magnetron, and 1 after cooling! iI
is partially branched, one goes through the inside of the refrigerator and goes outside the refrigerator, and the other is directly discharged outside the refrigerator. 10 is an exhaust duct, and 11 is a sensor whose resistance value changes depending on the amount of gas or humidity. 12 is a damper for changing the wind path resistance, 13 is the main body case, 1
4 is a leg, and 16, 16° and 17 are arrows to indicate the air path. The damper 12 controls the ratio of the amount of air flowing out of the refrigerator along arrows 15 and 16 and the amount of air directly exiting the refrigerator following arrow 17.

As a sensor, S is used, whose resistance value changes depending on gas and humidity.
It is assumed that nO2 or MgCv204-TiO2-based sintered bodies are used.

Figure 2 shows the humidity signal as an example: A when the air flow rate is large, and the sensor signal S (resistance value, the value obtained by collecting the resistance value as a voltage, and the resistance value as a capacitor) after the start of heating when the air flow rate is small. (such as those obtained as oscillation frequencies by combinations of) is shown. iK head Jjl: (11,
It can be divided into (It).

Region (1) shows how the relative humidity decreases as the magnetron temperature increases by 1. Area (1116
This indicates that the amount of steam generated from food is increasing.

20℃ as the condition for air flowing through arrows 15 and 16
60Lf3(RH) at 0.12m! /TruR, and when heating 200cc of water at 20℃ with 500W (radio wave output), after about 2 minutes it changes from area (1) to area (If
). Separation of water generated from load %10.2 g/5
The signal changes as A and B depending on the magnitude of ecQc. FIG. 3 shows an example of changes in the signal S according to the present invention, and FIG. 4 shows the state of the damper in relation to FIG.

The detection threshold value for automatically controlling microwave oven heating (b) is assumed to be ΔSs. To explain the operation, the damper is opened for a certain period of time (Ts) after heating starts;
Clean out air from previous cooking. After that, the damper is closed to reduce the amount of air blown into the refrigerator Qc to zero or to a small value. The detection point is where the signal S becomes the same as the set threshold value ΔSs in comparison with the lowest value Sm. The magnetron may be stopped at this signal detection point, or heating may be controlled after the detection point. If the damper is opened at this point, the excess gas in the refrigerator can be scavenged, so there will be no condensation.

As explained above, according to the present invention, the air flow inside the refrigerator is reduced until the borrowing is detected, and the air blower Fit-i is turned on after the detection, so the signal can be detected at high humidity, and after that the air flow is reduced. Since the amount of water is controlled to increase, it is possible to realize a product with the characteristic that there is no fear of condensation. When using a humidity sensor, etc., which is particularly sensitive to low humidity conditions or cannot be sufficiently ventilated, it is practical to reduce the internal air flow rate Qc to enable detection in high humidity areas. . It goes without saying that there is no need to open the damper if heating is to be stopped at the time of detection of the error.

In addition, when refreshing the sensor by heating with a heater, b
The larger the internal ventilation block, the faster the temperature will be lowered and measurement will be possible, but if the refresh is completed within the fixed time Ts shown in Figure 4, the rapid cooling conditions for the sensor will also be affected. Becomes Noh.

In addition, theory 1 above shows an example in which the disclosed scavenging timing (Ts) is set in the first half of heating, but it is also possible to shift it after heating is completed, to restrict the damper air volume only when the exhaust temperature is high, and to The degree of opening and closing of the damper may be controlled depending on the temperature to control the ventilation inside the refrigerator.

In the first embodiment, a case has been described in which the air after cooling of the magnetron cooling fan is used, but the air path may be changed as appropriate within the range where the magnetron cooling fan is used.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an automatic high-frequency heater showing an embodiment of the present invention, Fig. 2 is a time change characteristic diagram of a signal in the same control circuit, and Fig. 3 is a time change characteristic diagram of a signal in the present invention. FIG. 4 is an explanatory diagram showing an example of damper control in relation to FIG. 3. 1...Heating chamber (inside the warehouse), 8...Magnetron, 9...Blower fan (inside the warehouse)
, 11...Sensor, 12...Damper (
15.16...Arrow indicating the internal ventilation path, ts...Time of signal detection. Procedural amendment (method) 7 June 78, 1980 Commissioner of the Japan Patent Office 1 Indication of case 1988 Patent Application No. 59998 2 Name of invention Automatic high-frequency heater 3 Gatekeeper with case of person who corrects sleeves Special Permit Application Address 1006 Kadoma, Kadoma City, Osaka Prefecture Name (
582) Matsushita Electric Industrial Co., Ltd. Representative Toshihiko Yamashita 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 6 Date of amendment order, contents of amendment

Claims (5)

[Claims] (1)゛ It has a sensor that detects gas and humidity, an internal ventilation fan, and a control device that controls the amount of internal air flow, and the control device has at least An automatic high-frequency heater characterized in that it is configured to control an air blowing fan within a recording distance of <1> by changing the air blowing amount once. (2) White according to claim 1, which uses a magnetron cooling fan as the internal ventilation fan! 1iIJ high frequency heater. (3) After the signal is detected, the automatic high-frequency heater according to the first paragraph of the claim (!j1) in which the internal ventilation Fl: (4) The automatic high-frequency heater according to claim 1, which utilizes opening and closing of a damper as a device for controlling the amount of air blown inside the refrigerator. (5) The automatic high-frequency heater according to claim 1, wherein when heating continues even after the signal is detected, the amount of air blown inside the refrigerator is controlled from small to small.