JPH0835653A - Safety device for gas heating instrument - Google Patents

Abstract

PURPOSE:To eliminate the necessity of conduction of unnecessary great holding current even when the ambient temperature of a safety valve is changed, and permit the elongation of the life of a battery. CONSTITUTION:A safety valve B is arranged in the supplying passage of fuel gas for a combustion device 1. To the safety valve B current is fed by a power supply E, consisting of batteries, through a current control unit 2. An impressing voltage on the safety valve B is detected by a voltage detecting part 3. A control unit CN controls a current controlling unit 2 so as to conduct a working current necessary to open the safety valve B. The control unit CN determines a holding voltage, capable of obtaining a holding current necessary for maintaining the opening condition of the safety valve B, based on the impressing voltage on the safety valve B, which is detected by a voltage detecting part 3 during a period of conducting the working current. Further, the control unit CN controls the passing current of the current control part 2 so that a detecting voltage in the voltage detecting part 3 keeps the holding voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas heating device for burning a fuel gas such as city gas or propane gas, and to a safety device for the gas heating device provided with a safety valve on the combustion gas supply path.

[0002]

2. Description of the Related Art Conventionally, in a gas cooking appliance such as a gas stove or an oven, a gas heating appliance such as a bath gas stove, a gas stove, etc., a safety valve is provided on a fuel gas supply passage, and the safety valve is shut off when a combustion abnormality occurs. Therefore, it is considered to prevent accidents due to gas leakage and incomplete combustion.

In this type of safety device, as shown in FIG. 4, a power source E comprises a battery C and a constant voltage circuit RG, and a constant voltage is applied to a safety valve B. Further, a transistor Q having a collector-emitter inserted between the power source E and the safety valve B is provided, and when a sensor (not shown) detects a combustion abnormality, the control unit CN turns off the transistor Q. The safety valve B is shut off.
Here, in order to reduce the frequency of replacement of the battery C as the power source E, it is required to minimize the power consumption of the safety device. On the other hand, a solenoid valve is used as the safety valve B, and the holding current required to maintain the open state is small in the solenoid valve as compared with the moving current required to open the safety valve. In order to reduce the power consumption of, the holding current can be made as small as possible.

[0004]

By the way, it is generally known that the resistance of the coil of the solenoid valve changes depending on the ambient temperature, and a holding current is applied so that the solenoid valve can be kept open regardless of the ambient temperature. In that case, the voltage applied to the coil of the solenoid valve must be set so that the required holding current can be obtained with the maximum resistance value. Therefore, if the resistance value of the coil decreases due to the change of the ambient temperature, a current larger than the holding current required to maintain the open state of the coil of the solenoid valve will flow. Since the resistance value of the coil of the solenoid valve used for this type of safety valve changes in a wide range (for example, changes in 200 to 300Ω), a constant voltage is applied to the coil by using the constant voltage circuit RG as described above. Therefore, when the resistance value of the coil becomes small, the surplus of the holding current becomes large, resulting in a problem that the power consumption of the battery C cannot be made sufficiently small.

An object of the present invention is to solve the above problems and to provide a gas heating device which can prolong the battery life without the need to pass an unnecessarily large holding current even if the ambient temperature of the safety valve changes. It is intended to provide a safety device.

[0006]

According to a first aspect of the present invention, there is provided a safety valve including a solenoid valve arranged on a fuel gas supply path to a combustion device, a power source including a battery for supplying power to the safety valve, and power supply to the safety valve. A current control unit that is inserted into the passage to change the supply current to the safety valve, a voltage detection unit that detects the voltage applied to the safety valve, and a current control unit that controls the current flow so that the sensitive current required to open the safety valve is passed. The holding voltage required to maintain the open state of the safety valve is determined based on the voltage applied to the safety valve detected by the voltage detection unit during the And a control unit for controlling the passing current of the current control unit so as to maintain the holding voltage.

According to a second aspect of the present invention, a safety valve including a solenoid valve arranged on a fuel gas supply path to the combustion device, a power source including a battery for supplying power to the safety valve, and a safety valve inserted into the power supply path to the safety valve are provided. The current control unit that makes the supply current of the variable is variable, the voltage detection unit that detects the voltage applied to the safety valve, and the voltage during the period when the current control unit is controlled so that the moving current required to open the safety valve flows. Based on the voltage applied to the safety valve detected by the detection unit, the holding voltage that is the holding current required to maintain the open state of the safety valve is determined, and the voltage detected by the voltage detection unit is set to maintain the holding voltage. The control unit that controls the passing current of the control unit stores the holding voltage that is determined by passing a sensitive current through the safety valve, and the difference between the stored voltage and the applied voltage to the safety valve detected by the voltage detection unit when the safety valve is opened is Fixed It exceeds the value when, characterized in that it comprises a voltage correction unit that the current passing through the current control unit is re-determine the holding voltage is controlled such that the impressed current.

[0008]

According to the structure of the first aspect of the invention, the current control unit is controlled so that the holding current becomes a level required to maintain the open state after passing the sensing current to the safety valve, and the sensing current is passed. The holding voltage at which the holding current is obtained is determined based on the applied voltage of the safety valve during the current period, and the current control unit is controlled so that the applied voltage to the safety valve is maintained at the holding voltage during the period when the safety valve is in the open state. Therefore, even if the ambient temperature of the safety valve at the time of opening the safety valve is different, it is possible to flow a nearly constant holding current to the safety valve, which consumes less power than the conventional configuration that used only a constant voltage power supply. Can be suppressed, and the life of the battery as a power source can be extended.

According to the second aspect of the invention, the holding voltage determined during the period when the sensing current is flowing is stored,
The voltage applied to the safety valve is detected during the safety valve opening period,
When the difference between the detected voltage and the stored holding voltage exceeds a certain threshold value, the holding voltage is re-determined as a state in which the sensitive current is made to flow again, so that the holding current is maintained even if the ambient temperature changes while the safety valve is open. By re-determining, it is possible to always maintain an almost optimum holding current.

[0010]

【Example】

(Embodiment 1) In this embodiment, as shown in FIG. 1, a safety valve B composed of a solenoid valve is provided on a combustion gas supply path to a combustion device 1 for combusting a fuel gas like a gas burner. On the power supply path from the power source E to the safety valve B, the safety valve B
A current control unit 2 for controlling the supply current to is inserted. Further, a voltage detection unit 3 that detects the voltage applied to the safety valve B is provided. The control unit CN is provided with a resistance detection unit 4 that detects the resistance of the coil of the safety valve B based on the voltage detected by the voltage detection unit 3. A battery power source is used for the power source E.

A more specific description will be given. As shown in Figure 2
In the current controller 2, the emitter and collector are connected in series.
Two transistors Q₁, Q₂And resistance R, R₁₁,
R₁₂, R_{twenty one}, R_{twenty two}Consists of For excitation coil of safety valve B
Has a resistor R connected in series, and both transistors Q₁, Q₂of
The series circuit between the emitter and collector and the resistor R is connected to the power source E.
It is inserted between the exciting coil of the safety valve B. Also the voltage
The detector 3 averages the voltage across the exciting coil of the safety valve B.
Resistance R₁, R₂And capacitor C₁, C ₂And from
It is composed of an integrating circuit. Power source E is battery C and constant voltage
It consists of a circuit RG and the voltage across the battery C is a constant voltage circuit R.
The voltage is made constant by G. Here, battery C and constant voltage
Interlocked with the ignition and extinguishing operation of the combustion device 1 between the road RG
The power switch SW for switching is inserted. Controller CN is my
It is a black computer, and it is powered by the power supply E and is safe.
With the output voltage of the voltage detector 3 that detects the voltage across the valve B
Based on this, the resistance detection unit 4 built in the control unit CN (see FIG. 1)
The resistance value of the coil of safety valve B is calculated by
The current controller 2 is controlled based on the above. Also, not shown
However, a reset that resets the control unit CN when the power is turned on.
Circuit is provided.

Next, the operation of the controller CN will be described.
First, when the power switch SW is turned on, the control unit CN is reset by the reset circuit, and in the control unit CN, both transistors Q ₁ and Q ₂ of the current control unit 2 are turned on at the same time. In this state, since a DC voltage is applied to the safety valve B, Ohm's law is applied to the relationship between the output voltage of the voltage detection unit 3, the resistor R, and the constant voltage power supply RG, and the DC voltage of the coil of the safety valve B is applied. You can ask for resistance. That is, if the output voltage of the constant voltage circuit RG is V ₀ and the output voltage of the voltage detection unit 3 is V ₁ , the resistance value Rx of the coil of the safety valve B is
Rx = R · V ₁ / (V ₀ −V ₁ ). The resistance value Rx of the coil of the safety valve B can be obtained by performing this calculation by the resistance detection unit 4 provided in the control unit CN. The holding voltage applied to the coil of the safety valve B is determined from the resistance value Rx thus obtained and the target value of the holding current required to maintain the safety valve B in the open state. _{One of} the transistors Q ₁ and Q ₂ forming the current control unit 2 is switched by PWM control so that the voltage becomes the holding voltage (that is, switching is performed at a constant cycle and the on-duty is changed).

When the power is turned on as described above, the safety valve B is opened by continuously turning on both transistors Q ₁ and Q ₂ to allow a sensing current to flow, and at this time, the resistance value of the coil of the safety valve B is changed. After the safety valve B is opened, both transistors Q are connected so that the holding voltage determined based on the obtained resistance value is applied to the coil of the safety valve B.
_1, by switching one of Q _2, because in the flow a holding current necessary to maintain the open state of the safety valve B, the resistance value of the coil of the safety valve B is changed by the ambient temperature, unnecessary Without passing a large holding current to
As a result, the life of the battery C is extended.

(Embodiment 2) In Embodiment 1, the resistance value of the coil of the safety valve B is obtained when the power is turned on, and thereafter, the holding voltage determined by using the resistance value is fixedly applied to the coil of the safety valve B. . However, since the safety valve B is arranged near the combustion device 1, the ambient temperature of the safety valve B changes after the power is turned on (the combustion device 1 is started), and the resistance value of the coil of the safety valve B changes after the power is turned on. It will be. That is, since the holding voltage determined when the power is turned on is continuously applied to the coil of the safety valve B while the coil is kept open, the coil resistance value after the safety valve B is opened is changed. Cannot follow.

Therefore, in the present embodiment, an example is shown in which the change in the resistance value of the coil is detected and the holding voltage is corrected even after the safety valve B is opened. That is, as shown in FIG.
In the present embodiment, the control unit CN is provided with the voltage correction unit 5, and the voltage correction unit 5 holds the voltage determined by flowing a sensitive current through the coil of the safety valve B, or the voltage detection unit 3 at the time when the holding current starts to flow. Store the output voltage of. In addition, the output voltage of the voltage detection unit 3 is monitored during the period in which the safety valve B is in the open state, and when the difference from the stored output voltage exceeds a certain threshold value, the resistance value of the coil of the safety valve B is changed. As a result, both the transistors Q ₁ and Q ₂ of the current control unit 2 are turned on again, and the holding voltage applied to the safety valve B is recalculated. Thus, both transistors Q ₁ , Q ₂
When the difference between the output voltage of the voltage detection unit 3 and the stored holding voltage exceeds a threshold value, the applied voltage is recalculated so that the safety valve B is stored.
It is possible to follow the change in the resistance value of the coil during the opening of, and the power consumption can be further reduced as compared with the first embodiment. Here, it goes without saying that the threshold value is set within a range in which the holding current that can keep the safety valve B open can be kept flowing. Other configurations and operations are the same as those in the first embodiment, and thus the description thereof is omitted.

In each of the above embodiments, the voltage applied to the coil of the safety valve B is adjusted, but a resistor is connected in series to the coil of the safety valve B to keep the voltage across the resistor constant. A constant current may be caused to flow through the coil of the safety valve B by controlling 2. Further, since the control unit CN performs digital processing using a microcomputer, some voltage fluctuation does not affect the circuit operation, and a means for voltage detection is separately provided so that the output voltage of the power supply E can be known. Then, the constant voltage circuit RG is not always necessary.

[0017]

According to the first aspect of the present invention, the current control unit is controlled so that the holding current becomes a level necessary for maintaining the open state after the moving current is passed through the safety valve, and the moving current is passed. The holding voltage that gives the holding current is determined based on the applied voltage of the safety valve during the period, and the current control unit is controlled so that the applied voltage to the safety valve is maintained at the holding voltage during the period when the safety valve is in the open state. Even if the ambient temperature of the safety valve at the time of opening the safety valve is different, it is possible to pass an almost constant holding current to the safety valve, reducing power consumption compared to the conventional configuration that used only a constant voltage power supply. Therefore, there is an advantage that the life of the battery as a power source can be extended.

According to the second aspect of the present invention, the holding voltage determined during the period in which the sensing current is flowing is stored, the voltage applied to the safety valve is detected even during the opening period of the safety valve, and the detected voltage is stored. If the difference between the holding voltage and the holding voltage exceeds a certain threshold, the holding voltage is re-determined as a state in which the sensitive current is made to flow again, so by re-determining the holding current even if the ambient temperature changes while the safety valve is open, This has the advantage that the almost optimum holding current can be maintained at all times.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment.

FIG. 2 is a circuit diagram showing a first embodiment.

FIG. 3 is a block diagram showing a second embodiment.

FIG. 4 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 1 Combustion device 2 Current control unit 3 Voltage detection unit 4 Resistance detection unit 5 Voltage correction unit B Safety valve C Battery CN Control unit E Power supply

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Marusa, Kenji Marukasa 1-52 1 Minami-shi Oka, Minato-ku, Osaka Harman Co., Ltd. (72) Inventor Kazutoshi Adachi 1-52 Minami-shi Oka, Minato-ku, Osaka Co., Ltd. In Herman

Claims (2)

[Claims] 1. A safety valve including a solenoid valve arranged on a fuel gas supply path to a combustion device, a power source including a battery for supplying power to the safety valve, and a supply current to the safety valve inserted in the power supply path to the safety valve. Current control unit, a voltage detection unit that detects the voltage applied to the safety valve, and a voltage detection unit that detects the voltage applied to the safety valve during the period when the current control unit is controlled so that the moving current required to open the safety valve flows. Based on the voltage applied to the safety valve, the holding voltage required to maintain the open state of the safety valve is obtained.The holding voltage is determined and the voltage detected by the voltage detector passes through the current controller to maintain the holding voltage. A safety device for a gas heating appliance, comprising: a control unit for controlling an electric current. 2. A safety valve including a solenoid valve arranged on a fuel gas supply path to a combustion device, a power source including a battery that supplies power to the safety valve, and a supply current to the safety valve that is inserted into the power supply path to the safety valve and is variable. Current control unit, a voltage detection unit that detects the voltage applied to the safety valve, and a voltage detection unit that detects the voltage applied to the safety valve during the period when the current control unit is controlled so that the moving current required to open the safety valve flows. Based on the voltage applied to the safety valve, the holding voltage that is the holding current required to maintain the open state of the safety valve is determined, and the passing current of the current control unit is set so that the voltage detected by the voltage detection unit maintains the holding voltage. The control unit that controls the safety valve and the holding voltage that is determined by passing a sensitive current through the safety valve are stored, and the difference between the voltage applied to the safety valve detected by the voltage detection unit when the safety valve is opened and the stored voltage exceeds a certain threshold value. And current A safety device for a gas heating appliance, comprising: a voltage correction unit that controls the passing current of the control unit to be a moving current and redetermines the holding voltage.