JP2984476B2 - Cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object generated from an object to be heated.
The present invention relates to a heating cooker provided with a gas sensor for detecting a gas component based on a change in resistance value.

[0002]

2. Description of the Related Art For example, in a microwave oven equipped with an alcohol sensor, when cooking an object to be heated such as food stored in a heating chamber, a gas such as water vapor or alcohol generated from the food is detected and detected. In some cases, heating and cooking conditions are set according to the detected amount, or the type of food is determined.

In this case, the detection circuit for detecting water vapor or alcohol gas is usually constituted by using a gas sensor whose resistance value changes according to the amount of generated gas. And, for example, the detection circuit is configured to apply a predetermined voltage in a state where a resistor is connected in series with the gas sensor, and is configured to detect a gas generation amount by a terminal voltage appearing between both terminals of the gas sensor. I have.

In practice, since the initial resistance value of the gas sensor varies, if the resistance value of the series resistor is kept constant, the sensor terminal voltage at the start of the detection operation cannot be set to a predetermined value. The circuit is configured so that a plurality of types of resistors having different resistance values can be switched and connected to the gas sensor,
At the time when the heating and cooking are started, the resistance is switched so as to be connected in series with an appropriate resistance value, and the sensor terminal voltage is controlled to be constant.

[0005]

However, in the above-described conventional configuration, since the switching of the series resistance in the detection circuit of the gas sensor is performed at the start of heating and cooking, the following problems occur. That is, in the object to be heated containing alcohol, since the alcohol component is generated from the time of being contained in the heating chamber, at the time of starting the heating cooking, the heating chamber is already filled with the alcohol component. At this time, the resistance value of the alcohol sensor may have already changed due to the alcohol gas.

When the series resistance of the detection circuit is switched at the time when heating and cooking are started, the terminal voltage is set to a predetermined voltage in accordance with the state where the resistance value of the alcohol sensor is changing. Therefore, the change in the terminal voltage of the alcohol sensor after the start of the heating and cooking may be reduced, and the amount of alcohol generated may not be accurately detected.

For example, as shown in FIG. 6, in an alcohol sensor, since a resistor having an arbitrary resistance value is connected in series in an initial state, the terminal voltage Vout is larger than a predetermined voltage of 3 V, for example. It has become. When the object to be heated containing an alcohol component is accommodated in the heating chamber by opening the door of the heating chamber, the alcohol gas generated from the object to be heated is detected, and the resistance value of the alcohol sensor decreases. Terminal voltage Vou of alcohol sensor
t also decreases.

Thereafter, when heating and cooking are started, the terminal voltage Vout of the alcohol sensor is set to a predetermined voltage of 3 V. At this time, the alcohol gas has already been detected and the resistance value of the alcohol sensor has decreased. Even if the resistance value fluctuates according to the detected amount of alcohol gas generated by subsequent heating, the detected amount of alcohol gas is accurately detected because the detected amount is canceled despite the detection. You cannot do it. If the accurate amount of the alcohol gas generated from the object to be heated cannot be detected in this way, as described above, when setting the heating and cooking conditions or determining the type of the object to be heated, a correct judgment is made. It may not be possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a heating cooker capable of accurately detecting the amount of gas generated from an object to be heated housed in a heating chamber. To offer.

[0010]

SUMMARY OF THE INVENTION The present invention provides a gas chamber in a heating chamber.
Are those directed to a heating cooker having a gas sensor for detecting a scan by a change in resistance value, a setting unit for applying a voltage through a series resistor to the gas sensor, the door opening and closing the heating chamber is opened And a control means for controlling the setting means so that a terminal voltage of the gas sensor becomes a predetermined voltage when the door switch presents a detection state. Has features.

[0011]

According to the cooking device of the present invention, when the door of the heating chamber is opened, the door switch shows a detection state, and accordingly, the control means adjusts the terminal voltage of the gas sensor to a predetermined voltage. Control the setting means. As a result, the gas chamber is opened before the door of the heating chamber is opened and the object to be heated is stored inside.
A predetermined voltage is set between both terminals of the sensor . Therefore, when the gas sensor has the resistance value in the initial state before the gas is detected, the predetermined voltage is applied from the setting means via the series resistance, and the predetermined voltage is
The output voltage becomes a state in which no gas is detected.

Thus, when an object to be heated containing a gas component is accommodated in the heating chamber, even if gas is generated before heating and cooking is started, the gas is detected by the gas sensor.
The terminal voltage and the change in the terminal voltage.
The amount of gas generated by the subsequent heating cooking can also be accurately detected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a microwave oven having a function of heating by an electric heater will be described below with reference to FIGS. First, FIG.
As shown in FIG. 3 and FIG.
A heating chamber 3 whose front surface is opened and closed by a door 2 is provided. A rotating plate 4a on which the rotating plate 4 is placed is provided on the inner bottom of the heating chamber 3. The rotating plate 4 a is configured to be rotated by an RT motor 5 provided on the outer bottom of the heating chamber 3.

A heater 6 for grill cooking is provided on the ceiling of the heating chamber 3, and air in the heating chamber 3 is discharged to the outside of the main body 1 on the left side of the heating chamber 3. Exhaust duct 7 is provided. Inside the exhaust duct 7, an alcohol sensor 8 and a water vapor sensor 9 as gas sensors are provided. In this case, the alcohol sensor 8 has such a characteristic that its resistance value decreases in accordance with the detected amount of alcohol gas.

On the other hand, a machine room is provided on the right side of the heating chamber 3, in which microwaves are supplied into the heating chamber 3 via the waveguide 10 to perform range cooking. Is provided. An operation panel 12 is provided on the front of the machine room of the main body 1. The operation panel 12 is provided with an operation input switch 13 having various switches for the user to select a cooking menu or the like or to instruct the start of cooking, and a display 14 for displaying various messages or the like. I have. A door switch 15 (see FIG. 4) that outputs a detection signal indicating a detection state when the door 2 is opened is disposed inside the main body 1.

FIG. 4 is a schematic block diagram of an electric configuration of the microwave oven configured as described above. A control circuit 16 having a function as a control means is constituted by a CPU 1.
7, a ROM 18, a RAM 19, etc., and a heating cooking program (not shown) is stored in advance. An alcohol sensor 8, a water vapor sensor 9, a door switch 15 and an operation input switch 13 are connected to each input terminal of the control circuit 16, and the control circuit 16 receives various detection signals and various kinds of signals. An operation signal is input.

The output terminal of the control circuit 16 is connected to the above-described display 14 and a switching circuit 20 as setting means.
The magnetron 11 and the heater 6 are connected. The control circuit 16 controls the driving of the RT motor 5, the magnetron 11, and the heater 6 via the drive circuit 21, and provides a display signal to the display 14 to perform necessary display.
Heat cooking is performed. The control circuit 16 outputs a control signal to the switching circuit 20 to apply a voltage to both terminals of the alcohol sensor 8 as described later.

FIG. 1 shows the details of the electrical configuration of the switching circuit 20 and the alcohol sensor 8.
Is composed of, for example, six voltage adjusting resistors 22a to 22f having different resistance values Ra to Rf connected in parallel. Switches 23a to 23f are connected in series to each of the voltage adjusting resistors 22a to 22f. I have. These switches 23a to 23f are turned on and off by receiving a switching signal from each output terminal P1 to P6 of the control circuit 16. Note that the voltage adjustment resistor 22a
The values of the resistance values Ra through Rf of through 22f are, for example,
3.9 kΩ, 6.8 kΩ, 15 kΩ, 43
kΩ, 56 kΩ, and 75 kΩ are set.

One terminal of the alcohol sensor 8 is connected to a DC power supply terminal VD for applying a predetermined voltage (for example, 5 V) via the switching circuit 20, and the other terminal is grounded. Then, the control circuit 16 outputs a switching signal from any of the output terminals P1 to P6 to
To 23f, to apply a predetermined voltage to the alcohol sensor 8 via any of the voltage adjusting resistors 22a to 22f, and to input the terminal voltage Vout of the alcohol sensor 8 to the input terminal P0. I have.

Next, the operation of this embodiment will be described with reference to FIG. In the following description, the detection operation by the alcohol sensor 8 will be mainly described. First,
When the power is turned on, the control circuit 16 outputs the output terminal P
A switching signal is output from, for example, P1 of 1 to P6 to turn on the switch 23a of the switching circuit 20. Thus, a voltage of 5 V is applied to the alcohol sensor 8 from the DC power supply terminal VD via the voltage adjusting resistor 22a and the switch 23a. In this case, since the resistance value Rs of the alcohol sensor 8 varies depending on the product and also varies depending on the temperature and other conditions at that time, the value of the terminal voltage Vout input to the input terminal P0 of the control circuit 16 is constant. Since it does not take a value, for example, as shown in FIG. 5, it takes a value of 3 V or more.

In such a state, when the door 2 is opened to perform the heating cooking, a detection signal indicating the open state is input to the control circuit 16 from the door switch 15. As a result, the control circuit 16 detects the terminal voltage Vout of the alcohol sensor 8 input from the input terminal P0, and detects the terminal voltage Vout from one of the output terminals P1 to P6 so that the voltage value becomes, for example, 3 V as a predetermined voltage. The switching signal is output and set.

In this case, since the alcohol sensor 8 has not yet detected the alcohol gas, the terminal voltage Vout is set to 3 in the state where the resistance value Rs is in the undetected state.
V can be set to the reference voltage. Further, the terminal voltage Vout of the alcohol sensor 8 can be expressed as: Vout = 5 (V) × Rs / (Rs + RL). RL is the switch 23a
3 shows any one of the resistance values Ra to Rf of the voltage adjustment resistors 22a to 22f connected by the resistors 23a to 23f.

Thereafter, when the heating target A containing, for example, an alcohol component is accommodated in the heating chamber 3, the alcohol gas generated from the heating target A is released into the heating chamber 3. This alcohol gas is detected by the alcohol sensor 8 when flowing outside through the exhaust duct 7. Since the resistance value Rs of the alcohol sensor 8 changes so as to decrease in accordance with the amount of alcohol gas, the terminal voltage Vout also decreases. Control circuit 16
Can detect the amount of alcohol gas generated by detecting a deviation from the terminal voltage Vout and the reference voltage of 3 V. That is, it is possible to accurately detect the amount of alcohol generated before starting heating and cooking. Can be.

When the cooking is performed after the door 2 is closed, the alcohol gas generated from the object to be heated A is further detected by the alcohol sensor 8. Therefore, the control circuit 16 can accurately detect the amount of alcohol gas generated since the object A to be heated is accommodated in the heating chamber 3. Thus, for example, when a heating cooking program is executed, it is possible to accurately set the heating conditions according to the amount of alcohol gas generated, and to determine the type of the object to be heated based on the amount of alcohol gas generated. In this case, no erroneous determination is made.

According to this embodiment, the switching setting operation of the voltage adjusting resistors 22a to 22f of the switching circuit 20 connected in series to the alcohol sensor 8 is performed by the door switch 15 when the door 2 is opened. Since the detection is performed when a detection signal is received, the terminal voltage Vout of the alcohol sensor 8 can be set to the reference voltage in a state where the alcohol gas is not detected, and the subsequent detection of the amount of alcohol gas generated can be accurately performed. It can be carried out. Accordingly, accurate setting and discrimination can be performed in a setting operation and a discriminating operation based on the amount of alcohol gas generated by the heating cooking program.

In the above-described embodiment, the switching circuit 20 having a configuration in which the voltage adjusting resistors 22a to 22f are switched and used is used as the setting means. However, the present invention is not limited to this. By changing the applied voltage, the terminal voltage of the alcohol sensor 8 is set to, for example, 3V.
May be set to the predetermined voltage.

In the above embodiment, the case where the present invention is applied to a microwave oven has been described. However, the present invention is not limited to this, and can be applied to all heating cookers provided with a gas sensor .

[0028]

As described above, according to the cooking device of the present invention, when the door switch detects that the door of the heating chamber is open, the terminal voltage of the gas sensor is set to a predetermined voltage by the control means. Since the setting means is controlled, the terminal voltage in the undetected state of the gas sensor can be set to an accurate voltage value, whereby the gas generation amount of the object to be heated housed in the heating chamber can be accurately detected. It has excellent effects.

[Brief description of the drawings]

FIG. 1 is an electrical configuration diagram of a main part showing one embodiment of the present invention.

FIG. 2 is an external perspective view of the overall configuration.

FIG. 3 is a schematic longitudinal sectional front view of the entire configuration.

FIG. 4 is a block diagram of an electrical configuration.

FIG. 5 is an operation explanatory view showing a transition of a terminal voltage of the alcohol sensor.

FIG. 6 is a diagram corresponding to FIG. 5 showing a conventional example.

[Explanation of symbols]

1 is a main body, 2 is a door, 3 is a heating chamber, 7 is an exhaust duct, 8 is an alcohol sensor (gas sensor) , 9 is a water vapor sensor,
11 is a magnetron, 15 is a door switch, 16 is a control circuit (control means), 20 is a switching circuit (setting means), 22a
Reference numerals 22f to 22f indicate voltage adjustment resistors, and reference numerals 23a to 23f indicate switches.

Claims (1)

(57) [Claims] 1. A heating cooker having a gas sensor for detecting a change in resistance of the heating chamber of the gas, the gas
A setting unit for applying a voltage through a series resistor Susensa, a door switch that exhibits a detectable state when the door opening and closing the heating chamber is opened, the gas sensor when the door switch is exhibited detection state Control means for controlling the setting means so that the terminal voltage becomes a predetermined voltage.