KR20030029239A - A control method for fire sensing of microwave oven - Google Patents

Abstract

PURPOSE: A fire sensing operation control method for a microwave oven is provided to achieve in-advance prevention against fire by turning off power upon detection of fire in the cavity of microwave oven. CONSTITUTION: A fire sensing operation control method comprises a first step(300,310) of permitting a user to input a control signal when the microwave oven is provided with a variety of functions; a second step(320) of permitting the control unit to drive the damper to be open; a third step(330) of permitting the control unit to judge whether the temperature sensed through the thermistor of exhaust unit of microwave oven is higher than 160 Deg.C, if the damper is open; a fourth step(340) of turning off power if the temperature is higher than 160 Deg.C; a fifth step(350) of permitting the thermistor to sense the heat generated during cooking, and judging whether the tilt of voltage increases, if the damper is closed; a sixth step(360) of turning off power of microwave oven, if the tilt of voltage increases; and a seventh step(370) of judging whether the temperature of the thermistor has reached 270 Deg.C, and turning off power of microwave oven, if the temperature of the thermistor has reached 270 Deg.C.

Description

A control method for fire sensing of microwave oven

The present invention relates to a fire detection control method of a microwave oven, and more particularly, when a fire occurs in the cavity, the fire detection control method of the microwave oven to detect the fire occurrence to cut off the power.

Hereinafter, a fire detection control method for a microwave oven according to the prior art will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a typical microwave oven.

As shown in the figure, a cavity 1 serving as a frame of a microwave oven and a cooking chamber 2 are formed inside the cavity 1. In the cooking chamber 2, food is input and cooking is performed while being heated by the oscillation heat of the microwave or the heater.

On one side of the cavity 1, an electric component for oscillation of the microwave is installed, and the electric compartment 3 is provided. One side wall of the cavity 1 of the electric compartment 3 is equipped with a magnetron 4 for oscillating microwaves. The magnetron 4 irradiates microwaves into the cooking chamber 2. In addition to the magnetron 4, a plurality of electric component parts are installed in the electric compartment 3. Examples of the electrical components installed therein include a magnetron, a high voltage capacitor, a high voltage transformer and the like.

On the other hand, the front surface of the cavity 1 is formed by the front plate 5, the front plate 5 is a portion corresponding to the cooking chamber 2 is open. In addition, an inlet 6 is formed on the side wall of the cavity 1 that divides the cooking chamber 2 and the electric compartment 3. The inlet 6 is a portion through which air for sucking air into the cooking chamber 2 and discharging water vapor generated during cooking to the outside.

The upper plate 7 is installed on the upper surface of the cavity 1. An exhaust port 8 through which the air circulated in the cooking chamber 2 is discharged is formed on the upper plate 7. On the upper plate 7, various components including a heater 9 and a convection fan 14 are installed.

On the other hand, the upper plate 7 is formed with a porous portion 11 for minimizing the leakage of the microwave while sending the heat of the heater (9) to the interior of the cooking chamber (2). The heater 9 is installed on the porous portion 11 at the upper end of the cavity 1. The heater 9 transmits convection heat and radiant heat to the inside of the cooking chamber through the porous part 11 to heat the food. The heater 9 is covered by the heater cover 12, the heater cover 12 is formed so as to cover the entire porous portion 11, the radiant heat generated from the heater (9) cooking chamber ( It also serves to reflect inside of 2).

2 is a positional view showing a position of a damper provided in the microwave oven.

As shown in the drawing, the microwave oven according to the prior art is provided with a damper (13a, 13b) as a safety device for preventing the flame from burning out of the cavity (1) when a fire occurs in the oven cavity, the inside of the cavity A temperature fuse is attached or a thermistor is attached.

In the prior art, when a fire occurs in a cavity during cooking, when a flame is detected through a thermistor or a temperature fuse attached to the cavity, the thermistor or the temperature fuse shuts off the power.

Looking at the flow of the control according to the detection of the fire of the microwave oven according to the prior art as follows.

3 is an operation flowchart for the fire detection control of the microwave oven according to the prior art.

As shown in the figure, various modes for cooking in a microwave oven are provided (step 100), and a user inputs cooking details necessary in the cooking mode (step 110). In accordance with the input control signal, the dampers 13a and 13b are opened or closed.

That is, when the user inputs the cooking signal using the microwave, the damper is started in the open state according to the signal (step 120).

In the prior art, it was determined whether a fire occurred in a cavity in cooking using the microwave. Therefore, it detects whether the temperature inside the cavity detected by the thermistor is more than 160 degrees Celsius (step 130). If the detected temperature inside the cavity is more than 160 degrees Celsius (° C.), the controller controls the power to be cut off due to the power of the relay being turned off (step 140).

Accordingly, the problems of the fire detection control method of the microwave oven according to the prior art are as follows.

Conventionally, when microwave cooking, a temperature sensor for detecting the temperature inside the cavity was mounted inside the cavity to determine whether a fire occurred. Accordingly, the temperature sensor could not detect whether a fire occurred during the convection function.

In addition, the thermistor or temperature fuse has lost its function due to the flame when hot heat or fire occurs inside the cavity, which causes the flame to ignite and cause a fire.

Accordingly, an object of the present invention is to provide a fire detection control method of a microwave oven that detects and controls a fire when a fire occurs.

1 is an exploded perspective view of a typical microwave oven.

2 is a positional view showing a position of a damper provided in the microwave oven.

3 is an operation flow chart for the fire detection control of the microwave oven according to the prior art.

4 is a view showing the position of the thermistor for detecting the fire of the microwave oven according to the present invention.

5 is a control block diagram for detecting the fire of the microwave oven according to the present invention.

Figure 6 is a state table for controlling the power supply depending on whether the damper operating state.

7 is a state table showing the rate of change of voltage and temperature during cooking.

8a, 8b is an operational flow diagram according to the fire detection control of the microwave oven according to the present invention.

Explanation of symbols on the main parts of the drawings

1: cavity 2: cooking chamber

3: battlefield room 4: magnetron

5: Front plate 6: Intake vent

7: upper plate 8: exhaust port

9: heater 11: porous part

12: heater cover 13a, 13b: damper

14: convection motor S: thermistor

T: turntable

In the microwave fire detection control method according to the present invention, the step of setting the reference temperature 1 for determining whether a fire occurs in the cavity in the closed state of the damper, and controlling the opening / closing operation of the damper according to the cooking mode And monitoring whether the internal temperature of the cavity is higher than the set reference temperature 1 when the damper is in the closed state, and breaking the power supplied when detecting the occurrence of a fire in the monitoring step. It is composed.

Hereinafter, a control method for fire detection of a microwave oven according to the present invention will be described.

4 is a view showing the position of the thermistor for detecting the fire of the microwave oven according to the present invention.

As shown in the figure, the exhaust port 8 is provided with a thermistor S for sensing the temperature in the cavity 1. Accordingly, the oscillation heat of the heater 9 is introduced into the cavity 1 through the porous part 11, and the turntable T in the cavity 1 rotates to heat food by the introduced heat.

5 is a control block diagram for detecting the fire of the microwave oven according to the present invention.

A power supply unit 35 for supplying power to the microwave oven, a signal input unit 15 for inputting a cooking signal, a driving unit 30 for driving food to be heated according to a control signal of the signal input unit 15, And a temperature detector 20 for sensing a temperature in the cavity 1 and a controller 25 for determining abnormal overheating in the cavity 1 according to the sensed temperature and controlling the power to be cut off. An illustration showing the position of a thermistor for detecting fire in a microwave oven according to the present invention.

In the present invention, the thermistor S performs the role of the temperature sensing unit 20. However, this is one embodiment, the role of the temperature sensing unit 20 is possible for various applications.

The oscillation heat of the heater 9 is introduced into the cavity 1 through the porous part 11, and heats food in the cavity 1 due to the introduced heat. At this time, the thermistor S senses the temperature inside the cavity 1 to determine whether a fire has occurred from inside the cavity 1 of the microwave oven.

The temperature signal sensed by the thermistor S is transmitted to the controller 25, and the controller 25 recognizes this and determines whether a fire has occurred in the cavity 1 of the microwave oven according to the temperature signal. . Accordingly, when the controller 25 determines that a fire has occurred in the cavity 1, the controller 25 controls to cut off the power.

6 is a state table for controlling power according to whether the damper is in an operating state.

As shown in the figure, when the damper is opened, the thermistor S located in the exhaust port senses the temperature in the cavity 1. The thermistor S transmits the temperature signal to the controller 25 when the sensed temperature is 160 degrees Celsius or more, and the controller 25 determines that a fire has occurred in the cavity 1, Control the power off.

On the other hand, when the damper is closed, the thermistor S located in the exhaust port senses the temperature inside the cavity 1. When the temperature detected by the thermistor S is 270 degrees (° C.) or more, the temperature signal is transmitted to the controller 25, and the controller 25 determines that a fire has occurred in the cavity 1, and thus, power supply. Control it to be blocked.

7 is a state table showing the rate of change of voltage and temperature during cooking.

When a fire occurs in the cavity 1, the thermistor S detects that a fire has occurred in the cavity 1 as the temperature suddenly rises due to the change of the flame. That is, as shown in the drawing, as the voltage drops sharply as the voltage decreases to a negative value, it means that the temperature rises sharply, and the inside of the cavity 1 is caused by the sudden temperature rise. It is determined that a fire has occurred. The larger the slope of the graph means that the temperature in the cavity is rapidly increased.

Including the above configuration, the operation flow of detecting and controlling a fire in a microwave oven is as follows.

8A and 8B are flowcharts illustrating operations of fire detection control of a microwave oven according to the present invention.

All cooking functions are provided in the microwave oven (step 200). In this state, the user inputs a cooking signal (operation 210). The controller 25 determines the cooking according to the input cooking signal, and the controller 25 controls the damper to be driven in an open or closed state according to the input signal.

When the input signal is cooking using microwaves, the controller 25 controls the damper to be driven in an open state (step 220).

When the damper is driven in the open state by the control, the thermistor provided in the exhaust port of the microwave oven senses the temperature inside the cavity. The control unit 25 determines that the maximum temperature detected when the damper is opened is preset, and when the maximum temperature is reached, the control unit 25 determines that a fire has occurred in the cavity. The preset maximum temperature is 160 degrees Celsius.

That is, when the damper is opened, the controller 25 determines whether the temperature sensed through the thermistor S is 160 degrees (° C.) (step 230). In response to the determination of the controller 25, the controller 25 detects that a fire has occurred in the cavity, and controls the controller 25 to stop driving of the relay. The relay for driving the magnetron is stopped. Accordingly, the power is turned off (step 240).

If the cooking signal input by the user is a convection mode or a speed cook in operation 220, the electric heating heater is driven.

If the cooking signal input by the user needs to be heated using microwave, the microwave is heated directly to the food, so there is no problem in heating the food itself even if the ambient air is low, so even if cold air is introduced into the cavity, No big difference occurs.

However, when food is heated by a heater, the air temperature around the food must be heated to a very high temperature. Therefore, when the heat inside the cavity should not escape to the outside, the damper is used to block the inflow portion through which the air flows to prevent air from entering the cavity, thereby preventing the leakage of heat inside the cavity. Therefore, in the convection mode, the damper for preventing the flow of air into the cavity is controlled by a closing algorithm.

The damper is closed, and the thermistor S provided in the exhaust port senses the heat generated during the cooking process (S250). When the damper is closed, when a fire occurs in the cavity of the microwave oven, the flame does not come out of the cavity, but the thermistor (S) senses that the temperature in the oven suddenly rises.

The thermistor S is set to the highest temperature in the chamber detected by the cavity 1. When the maximum temperature is reached, the controller detects that a fire has occurred in the cavity and transmits the signal to the controller 25. The maximum temperature of the thermistor S in this control operation flow chart is 270 degrees (° C).

Alternatively, when the voltage for driving the relay according to the temperature suddenly decreases in operation 250, the signal is transmitted to the controller 25. The signal is input to the controller 25, and the controller 25 detects that the inside of the cavity is high temperature or a fire has occurred. The control unit 25 displays a signal indicating that a fire has occurred on the display unit (not shown), and turns off the driving of the relay so that the driving of the microwave oven is stopped. This turns the power off (step 260).

Looking at another control flow chart for the fire detection control method of the microwave oven according to the present invention.

All cooking functions are provided in the microwave oven (step 300). In this state, the user inputs a cooking signal (S310). The controller 25 determines the input signal, and the controller 25 controls the damper to be driven in an open or closed state according to the input signal.

If the input signal is cooking using microwaves, the controller 25 controls the damper to be driven in an open state (step 320).

When the damper is driven in the open state by the above control, the thermistor S provided in the exhaust port of the microwave oven senses the temperature inside the cavity 1. The controller 25 presets a maximum temperature detected when the damper is opened, and when the maximum temperature is reached, the controller 25 determines that a fire has occurred in the cavity. The maximum temperature preset in the controller is 160 degrees Celsius.

That is, when the damper is opened, the controller 25 determines whether the temperature sensed through the thermistor S is 160 degrees (° C.) (step 330). In response to the determination of the controller 25, the controller 25 detects that a fire has occurred in the cavity 1, and controls the controller 25 to stop driving of the relay. The relay for driving the magnetron is stopped. Accordingly, the power is turned off (step 340).

In operation 320, when the cooking signal input by the user is a convection mode or a speed cook, the electric heating heater is driven.

If the cooking signal input by the user needs to be heated using microwave, the microwave is heated directly to the food, so there is no problem in heating the food itself even if the ambient air is low, so even if cold air is introduced into the cavity, No big difference occurs.

However, when food is heated by a heater, the air temperature around the food must be heated to a very high temperature. Therefore, when the heat inside the cavity should not escape to the outside, the damper is used to block the inflow portion through which the air flows to prevent air from entering the cavity, thereby preventing the leakage of heat inside the cavity. Therefore, in the convection mode, the damper for preventing the flow of air into the cavity is controlled by a closing algorithm.

The damper is closed, and the thermistor S provided in the exhaust port senses heat generated during the cooking operation (operation 350). When the damper is closed, as shown in FIG. 7, when the voltage gradient according to the temperature increases (step 350), it detects that a fire has occurred in the cavity and transmits the signal to the controller 25. The control unit 25 receiving the signal controls to cut off the power of the microwave oven (360).

On the other hand, if the thermistor S does not detect the increase in the slope of the voltage according to the temperature in step 360, it is detected whether a fire has occurred in the cavity according to the final temperature. That is, the thermistor (S) has a maximum temperature set to 270 degrees (° C.), and if the fire is not detected inside the cavity even by a change in the slope of the voltage according to the temperature, the maximum temperature detected by the thermistor (S) When the temperature reaches 270 degrees Celsius (step 370), the detection signal is transmitted to the controller 25. The controller 25 controls the power to be cut off according to the input detection signal (360).

In the present invention, when the damper is driven by the closing algorithm, the fire generated in the cavity can be detected using the thermistor.

According to the present invention as described above, when the damper is in a closed state, using a thermistor mounted to the exhaust port of the microwave oven to detect the temperature inside the cavity, when the detected temperature is a predetermined maximum temperature, the temperature It is a basic technical idea that a signal is transmitted to a control part and the control part cuts off power.

At this time, when the slope of the voltage at which the relay is driven increases according to the temperature to a negative size, it detects that a fire has occurred in the cavity. However, when it is not detected even by the slope of the voltage according to the temperature, the final temperature is sensed and the control unit controls the detected signal.

The rights of the present invention are not limited to the embodiments described above but are defined by what is stated in the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

According to the detection is to allow the user to prevent the fire in advance.

Therefore, when a fire occurs in the cavity due to the present invention, it is possible to extinguish the fire beforehand by shutting off the power by detecting the temperature sensor. In addition, the safety of the product can provide the user with satisfaction.

Claims (3)

Setting a reference temperature 1 for determining whether a fire has occurred inside the cavity in a closed state of the damper; Controlling an open / close operation of the damper according to the cooking mode; Monitoring whether the temperature inside the cavity rises above the reference temperature 1 when the damper is in the closed state; In the monitoring step, the fire detection control method of the microwave oven comprising the step of breaking the power supply when detecting the occurrence of a fire. The method of claim 1, In the closed state of the damper, the fire detection control method of the microwave oven further comprises the step of determining whether a fire occurs in the cavity using the slope of the voltage according to the temperature. Setting a reference temperature 2 for determining whether a fire has occurred in the cavity while the damper is opened; The fire detection control method of the microwave oven further comprises the step of detecting the occurrence of a fire by comparison with the set reference temperature 2 in the open state of the damper.