JPH09119645A - Control circuit for gas cooking equipment - Google Patents

Abstract

(57) Abstract: The present invention relates to a gas cooking appliance, and an object thereof is to ensure the safety of the gas cooking appliance. A flame detection flame rod (4), an AC power supply (3) for applying a voltage to the flame rod (4), and a first clock pulse voltage signal (7) for converting a combustion signal by a current from the flame rod (4). Converting means for converting the first clock pulse voltage signal 7 into an opposite phase by the phase inverting element 6 to form a second clock pulse voltage signal, and the second clock pulse voltage. The signal 8 is input, and the microcomputer is configured to monitor the combustion state at the voltage level. With this configuration, it is possible to prevent the raw gas from flowing out even if there is a misfire due to boiling over or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas cooking appliance, and more particularly to improving the safety of its combustion detecting device.

[0002]

2. Description of the Related Art In recent years, in order to improve the safety of combustion equipment, especially gas cooking equipment, a safety device such as an extinguishing safety device, a combustion detection device, and a safety device for preventing a fire caused by forgetting to turn off the oil during cooking have been widely used. Therefore, the need to install it in low-cost gas cooking equipment has increased.

A conventional combustion detection circuit for a gas cooking appliance will be described with reference to FIG. In the figure, when the power source is turned on, a current 10 flows from the AC power source 3. The field effect transistor 5 is turned on by this current, and the output current from the terminal A of the microcomputer 11 flows through this field effect transistor to the ground.

Next, when a combustion state is set, a flame rod current 9 flows through the flame rod 4. This is because in the combustion state, the resistance of the burning portion is significantly lower than the air resistance when not burning. Therefore, the current 10 stops flowing and the field effect transistor 5 is turned off. Therefore, the output current from the terminal A of the microcomputer 11 is input to the terminal B.

That is, the frame rod current 9 is converted by the field-effect transistor 5 into a clock pulse voltage signal 17 output from the microcomputer 11 and having a frequency equal to the frequency of the AC power supply 3, and the clock pulse voltage signal 17 is converted into a microcomputer. It is a circuit for monitoring the combustion state of the gas cooking equipment by inputting to 11. The clock pulse voltage signal 17 is input in the combustion state, and 0 in the non-combustion state.
V is input.

[0006]

However, in the above-mentioned conventional configuration, the combustion signal by the current from the flame rod 4 for combustion detection is converted into the clock pulse voltage signal 17, and the clock pulse voltage signal 17 is converted into the microcomputer 11.
In the method of monitoring the combustion state by inputting to the voltage level,
When a short-circuit failure occurs between the pattern of the conversion device for converting the clock pulse voltage signal 17 and the pattern of the input port of the microcomputer 11, a pseudo combustion signal is formed, so that misfire due to spillage or the like occurs. Nevertheless, the microcomputer 11 determines that the ignition is occurring and holds the gas valve in the open state, so that the raw gas flows out.

Further, the clock pulse voltage signal 17 has the same clock pulse voltage signal 1 as the frequency of the AC power supply 3.
In Fig. 7, when power supply noise occurs, a pseudo combustion signal that is synchronized with the clock pulse voltage signal 17 is formed, so that the microcomputer 11 indicates that ignition has occurred despite misfiring due to spillage or the like. Judgment is made and the gas valve is kept open, so raw gas flows out.

In view of the above, the present invention has a first object of safety and a second object of economically constructing a control circuit for a gas cooking apparatus which solves the above-mentioned conventional drawbacks.

[0009]

To achieve the above object, the present invention provides a combustion detection frame rod, an AC power supply circuit for applying a voltage to the combustion detection frame rod,
First conversion means for converting a combustion signal due to the current from the combustion detecting frame rod into a first clock pulse voltage signal, and a second clock pulse for converting the first clock pulse voltage signal into an opposite phase The second conversion means forming a voltage signal and the microcomputer for inputting the second clock pulse voltage signal and monitoring the combustion state at the voltage level are adopted.

With this configuration, the combustion signal due to the current from the combustion detecting flame rod is converted into the first clock pulse voltage signal, the first clock pulse voltage signal is converted into the opposite phase, and the second clock pulse is generated. By configuring the voltage signal, the voltage level of the opposite phase is maintained even if the pattern is short-circuited due to a component failure or the like in the state where the conversion device for converting the first clock pulse voltage signal and the input port of the microcomputer are adjacent to each other. Therefore, the microcomputer determines that the gas is abnormal, controls the gas valve to be in a closed state, and prevents the raw gas from flowing out even if a misfire due to spillage or the like occurs.

[0011]

To achieve the above object, the first means of the control circuit for a gas cooking appliance according to the present invention uses a combustion signal generated by a current from a combustion detecting frame rod as a first clock pulse voltage signal. The first conversion means for conversion and the second conversion means for converting the first clock pulse voltage signal into the opposite phase and forming the second clock pulse voltage signal are provided.

Further, the second means of the present invention comprises a third conversion means for converting the second clock pulse voltage signal into a third clock pulse voltage signal different from the power supply frequency.

The third means of the present invention uses a microcomputer to form the third clock pulse voltage signal.

Further, the fourth means of the present invention uses an electronic component to form the third clock pulse voltage signal.

The operation of the present invention will be described below. According to the first means of the present invention, the combustion signal due to the current from the flame rod for combustion detection is converted into the first clock pulse voltage signal, and the first clock pulse voltage signal is converted into the opposite phase. By configuring the clock pulse voltage signal of the above, the voltage level is maintained even when the conversion device for converting into the first clock pulse voltage signal and the input port of the microcomputer are adjacent to each other and the pattern is short-circuited due to a component failure or the like. This is a control circuit for a gas cooking device in which the microcomputer determines that there is an abnormality because of the opposite phase, controls the gas valve to the closed state, and raw gas does not flow out even if there is a misfire due to spillage or the like. Further, if the converting means for forming the second clock pulse is composed of a general-purpose IC, it can be easily and economically constructed, and since it is a simplified circuit, control of a gas cooking appliance with a low failure rate is possible. It becomes a circuit.

According to the second means, by converting the second clock pulse into a third clock pulse voltage signal different from the power supply frequency, power supply noise synchronized with the power supply frequency is generated, and the second clock pulse is generated. Even if the clock pulse voltage signal is formed in synchronization with the clock pulse voltage signal of 2,
Since the frequency is different, the position of the voltage level input to the microcomputer is also different, the microcomputer judges that it is abnormal, controls the gas valve to the closed state, and even if there is a misfire due to spillage etc., raw gas will flow out and a gas explosion will occur It is a control circuit for gas cooking equipment that is not dangerous.

According to the third means, the clock pulse voltage signal can be easily constructed by constructing the third clock pulse voltage signal by the microcomputer.

According to the fourth means, the clock pulse voltage signal can be economically constructed by constructing the third clock pulse voltage signal with an electronic component.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a combustion detection circuit according to the present invention, in which a flame rod current 9 flows from the flame rod 4 when the gas cooking appliance enters a combustion state. The frame rod current 9 is transferred to the microcomputer 1 by the field effect transistor 5.
The first conversion means in the microcomputer 1 converts the first clock pulse voltage signal 7 output from the. The first
Of the first clock pulse voltage signal 7 is converted into an opposite phase using the phase inverting element 6, and the second clock pulse voltage signal 8 is constituted by the second converting means. It is a circuit for monitoring the combustion state of the gas cooking appliance by inputting the clock pulse voltage signal 8 of 2 to the microcomputer 1. The second clock pulse voltage signal 8 is input in the combustion state, and 0 V is input in the non-combustion state.

The first clock pulse voltage signal 7 of the present embodiment is the third clock pulse voltage signal 7 when it is output from the microcomputer 1.
The clock pulse voltage signal is converted into a third clock pulse voltage signal having a frequency different from the frequency of the AC power supply 3 by the microcomputer 1 which is the conversion means. Further, the third conversion means can also be configured by an electronic component.

[0021]

From the above description, in the control circuit of the gas cooking appliance according to claim 1 of the present invention, the combustion signal due to the current from the flame rod for combustion detection is converted into the first clock pulse voltage signal, and the first clock pulse voltage signal is converted. Between the pattern of the conversion device for converting the clock pulse voltage signal of the above into the first clock pulse voltage signal by converting the clock pulse voltage signal into the opposite phase and the second clock pulse voltage signal, and the pattern of the input port of the microcomputer. Even if a short-circuit failure occurs, a pseudo combustion signal is not formed, and the microcomputer does not erroneously determine that it is igniting despite misfiring due to spillage or the like. Therefore, it is possible to provide to the market a gas cooking device in which raw gas does not flow out even if a fire is lost due to spillage or the like.
Further, if the converting means for forming the second clock pulse is configured by a general-purpose IC, it can be easily configured at low cost, so that it can be mounted on a low-priced gas cooker and is safe in the market. Since the popularity of products has increased and the circuit has been simplified, the structure is simple.

According to a second aspect of the present invention, by converting the second clock pulse voltage signal into a third clock pulse voltage signal having a frequency different from the power supply frequency, power supply noise is generated and the second clock pulse voltage signal is generated. Even when synchronized with the clock pulse voltage signal, since a pseudo combustion signal is not formed, the microcomputer does not erroneously determine that ignition has occurred despite misfire due to spillage or the like. Therefore, it is possible to provide to the market a gas cooking device in which raw gas does not flow out even if there is a misfire due to spillage or the like.

According to a third aspect of the present invention, the third clock pulse voltage signal is constituted by a microcomputer,
Since the clock pulse voltage signal can be easily configured,
The structure is simple and does not easily break down.

According to a fourth aspect of the present invention, the third clock pulse voltage signal is composed of electronic parts.
Since the clock pulse voltage signal can be economically configured, it can be installed in a low-priced gas cooker, and the diffusion rate of safe products in the market can be increased.

[Brief description of the drawings]

FIG. 1 is a combustion detection circuit diagram of a gas cooking appliance according to an embodiment of the present invention.

FIG. 2 is a combustion detection circuit diagram of a conventional gas cooking device.

[Explanation of symbols]

 1 Microcomputer 2 DC 5V power supply 3 AC power supply 4 Frame rod 7 First clock pulse voltage signal 8 Second clock pulse voltage signal 9 Frame rod current

Claims (4)

[Claims] 1. A combustion detection frame rod, and an AC power supply circuit for applying a voltage to the combustion detection frame rod.
First conversion means for converting a combustion signal due to the current from the combustion detecting frame rod into a first clock pulse voltage signal, and a second clock pulse for converting the first clock pulse voltage signal into an opposite phase A control circuit for a gas cooking appliance, comprising: a second conversion unit that forms a voltage signal; and a microcomputer that inputs the second clock pulse voltage signal and monitors a combustion state at a voltage level. 2. A control circuit for a gas cooking appliance, comprising a third conversion means for converting the second clock pulse voltage signal into a third clock pulse voltage signal different from the AC power supply frequency. 3. A control circuit for a gas cooking appliance, wherein the third converting means is composed of a microcomputer. 4. A control circuit for a gas cooking appliance, wherein the third converting means is composed of electronic parts.