JPH1019629A - Gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a special dummy load resistor and a special circuit for applying a test current to the special resistor for determining valve driving ability. SOLUTION: As a solenoid valve for shutoff and reset of gas, a self retaining type of opening-closing valve 2 is used which may be electrically opened and closed. To determine the valve driving ability of a battery 4, first, a microcomputer 1 determines if the opening-closing valve 2 is open or closed according to the state of signal output to a valve control circuit 5. If opened, an open valve signal is issued from an output port 1c to apply a current to the coil 2a of the opening-closing valve 2 in the direction of the solid line arrow A. The voltage of the battery 4 this time is detected with a voltage detection circuit 7. If closed, a closed valve signal is issued from the output port 1d to apply a current to the coil 2a in the direction of the broken line arrow B. The voltage of the battery 4 at this time is measured with the voltage detection circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement of a gas meter having a safety function.

[0002]

2. Description of the Related Art A built-in microcomputer constantly monitors a gas flow rate, and when it is determined that a gas flow rate abnormality or a gas continuous use time abnormality has occurred, or a built-in gas pressure sensor detects an abnormal decrease in gas pressure. 2. Description of the Related Art Gas meters having a so-called safety function that closes a shutoff valve to stop gas supply when a built-in seismic sensor detects an earthquake with a seismic intensity equal to or greater than a predetermined value are well known.

[0003] In an emergency, the shut-off valve is actuated by a shut-off signal output from a microcomputer and is closed. The shut-off signal is output for a short time necessary to close the shut-off valve composed of an electromagnetic valve, and turns on a transistor connected in series with the exciting coil of the shut-off valve for a short time, and through the transistor. An exciting current flows from the battery to the exciting coil, and the shutoff valve is closed.

The closed shut-off valve has a structure in which the closed state is maintained even during the non-excitation state after the cut-off signal disappears in a short time. After the abnormality disappears, the shut-off valve is manually returned and opened, and the gas supply is restarted.

In a gas meter having a microcomputer of this type, if the voltage of the battery drops below the minimum operating voltage of the shut-off valve, the shut-off valve cannot be closed by the shut-off signal in an emergency. Is impaired.

Therefore, a circuit for temporarily supplying a current to a pseudo resistor (load resistor) corresponding to the resistance value of the exciting coil of the shut-off valve is added to input the same signal as the shut-off signal, and the terminal voltage of the battery at that time is input. Has been provided with a function of detecting whether the voltage is equal to or higher than the shut-off valve operating voltage and determining the shut-off valve driving capability of the battery.

In order to detect the battery voltage drop, it is not necessary to actually supply a current to the shut-off valve built in the gas meter and to detect the terminal voltage of the battery at that time. It closes and the gas supply stops.
Since it is not a good idea to stop the gas in order to detect the battery voltage drop, such a method cannot be taken.

[0008]

In the above prior art,
The current flowing through the pseudo-resistance and the current flowing through the exciting coil of the valve when the valve is actually closed due to the difference in resistance and inductance between the pseudo-resistance and the shut-off valve excitation coil, and the difference in the temperature coefficient of the resistance, that is, the temperature characteristic. Therefore, the terminal voltage of the battery when a current flows through the pseudo resistor and the terminal voltage of the battery during actual driving have different values, and the detection of the battery voltage for determining the driving capability of the battery is accurate. There was a problem that can not be performed.

[0009] Further, in order to detect a decrease in the battery voltage which is performed to determine the driving capability of the battery, a special resistor or a circuit for supplying a test current to the pseudo resistor is required, and parts for the test are required. There was also a problem that the circuit became complicated.

Therefore, an object of the present invention is to provide a gas meter that can solve such a problem.

[0011]

In order to achieve the above object, according to the present invention, a battery for a power supply, a solenoid valve for stopping gas supply, and an excitation coil of the solenoid valve are temporarily supplied from the battery. A valve drive circuit that closes the solenoid valve by flowing current
In a gas meter having a microcomputer which supplies an exciting current from a battery to an electromagnetic valve via the valve drive circuit in the event of an emergency by judging a gas flow rate abnormality or the like, a one-way driving current is temporarily passed through the exciting coil (2a). As a result, the valve is closed,
The valve is kept closed even after the current is cut off, and is opened by temporarily supplying a drive current to the exciting coil (2a) in the other direction. The valve is kept open even after the current is cut off. A holding on-off valve (2) and the exciting coil (2a)
Valve drive circuit (3) for allowing one-way or reverse-direction drive current to flow through
And a valve control circuit (5) for controlling the valve drive circuit (3)
And outputs a valve closing signal for closing the on-off valve (2) in an emergency or the like to the valve control circuit (5) temporarily, if necessary, and if necessary, operates the on-off valve (2). A microcomputer (1) for temporarily outputting an open valve opening signal to the valve control circuit (5); and a voltage detection signal for detecting the voltage of the battery (4). ) And a microcomputer (1) for judging the valve driving capability of the battery, determine whether the state of the on-off valve (2) is open or closed by the valve control circuit. After confirming by the signal output state to (5), if the valve is open, the valve open signal is output.
In the closed state, a valve closing signal is temporarily sent to the valve control circuit (5), and a voltage detection command signal for operating the voltage detection circuit (7) is sent out. A gas meter for detecting whether the voltage is lower than a driving voltage.

According to a second aspect of the present invention, in the gas meter according to the first aspect, a driving current is supplied to the on-off valve (2) via the valve driving circuit (3) as a power supply battery.
And a second battery (6) for supplying power to the microcomputer (1) and the valve control circuit (5), and a voltage detection circuit (7) is provided for the first battery (4). It is characterized by detecting a voltage.

[0013]

FIG. 1 is a block diagram of a main part of a preferred embodiment of the present invention, and FIG. 2 is a specific electric circuit diagram of the block diagram of FIG.

In both figures, reference numeral 1 denotes a microcomputer for controlling the entire gas meter, and 2 denotes an on-off valve built in the gas meter. When a current in one direction is applied to the exciting coil 2a temporarily, the valve closes to cut off the current. A self-holding type electromagnetic device that operates so as to maintain the valve-closed state even after the valve is opened and to temporarily maintain the valve-opened state after the valve is opened and the current is cut off when a current in the other direction is temporarily supplied to the exciting coil 2a. It is a valve.

The on-off valve 2 is provided at the inlet of the gas meter like a conventional shut-off valve of a gas meter having a safety function, and allows gas to pass when the valve is open and stops gas supply when the valve is closed.

Reference numeral 3 denotes a valve drive circuit, which includes four transistors T
1, T2, T3 and T4 are connected in a bridge as shown in the figure. The connection point (collector) between the transistors T1 and T4 is connected to one end (the lower end in the figure) of the exciting coil 2a of the on-off valve 2, and the connection point (collector) between the transistors T2 and T3.
Is connected to the other end (the upper end in the figure) of the exciting coil 2a.

The emitters of the transistors T2 and T4 are both grounded, and the emitters of the transistors T1 and T3 are both connected to the positive terminal of the first battery 4 for driving the valve.
The negative terminal of the first battery 4 is grounded.

R1, R2, R3 and R4 are base resistors connected to the respective bases of the bridge-connected transistors T1, T2, T3 and T4. 5 is a valve control circuit,
Inverters A1, A2, transistors T5, T6, T7
And T8, and base resistors R5, R6, R7 and R8, etc. are connected as shown in the figure.

The collectors of the transistors T5 and T6 are connected to the bases of the transistors T1 and T2 of the valve drive circuit 3 via base resistors R1 and R6, respectively. Also,
The collectors of the transistors T7 and T8 are connected to the transistor T3 of the valve driving circuit 3 via base resistors R3 and R4, respectively.
And the base of T4.

The emitters of the transistors T5 and T7 are both grounded. The emitters of the transistors T6 and T8 are both connected to the positive terminal of the second battery 6 for the control circuit. The negative terminal of the second battery 6 is grounded. The operating power of the inverters A1 and A2 is supplied from the second battery 6.

Reference numeral 7 denotes a voltage detection circuit, as shown in FIG.
When a voltage detection command signal is received from the output port 1a of the microcomputer 1, it is detected whether the voltage of the first battery 4 is a constant value, that is, the minimum drive voltage of the on-off valve 2 or less, and the battery voltage detection signal is Send to port 1b.

As shown in FIG. 2, the voltage detection circuit 7 is constituted by connecting a voltage detector 7A formed of a well-known integrated circuit, a transistor T9, and resistors R9, R10, R11 and R12.

The input terminal 7a of the voltage detector 7A is connected to a resistor R9.
The output terminal 7b is connected to the input port 1b of the microcomputer 1, and the ground terminal 7c is grounded via the transistor T9.

The series connection of the resistors R9 and R10 functions as a voltage divider for dividing the voltage of the first battery 4 and inputting it to the input terminal 7a of the voltage detector 7A, and the resistor R11 functions as a pull-up resistor.

In FIG. 2, when an "H" level voltage detection command signal is output from the output port 1a of the microcomputer 1, the transistor T9 is turned on and the voltage detector 7A operates. When the voltage of the first battery 6 at that time is equal to or higher than the predetermined value, the output terminal 7c goes to the “H” level, and when the voltage is less than the predetermined value, the output terminal 7c goes to the “L” level. Send to port 1b.

The determination of the valve driving capability of the first battery 4 for valve driving is performed in the same manner as when the battery 4 is supplied to the exciting coil 2a via the valve driving circuit 3 during normal valve opening and valve closing. , A current is temporarily supplied for a short time, and the voltage of the battery 4 at that time is detected by the voltage detection circuit 7.

In determining the valve driving capability of the battery 4, the microcomputer 1 checks whether the state of the on-off valve 2 is the open state or the closed state by the signal output state to the valve control circuit 5.
If the valve is open, an "H" level valve opening signal is sent from the output port 1c of the microcomputer 1 to the transistor T5 and the inverter A1 for a short time.

Then, the transistors T5 and T1 are turned on, and the valve opening signal is inverted by the inverter A1 to turn on the transistors T6 and T2. Therefore, the on-off valve is opened from the first battery 4 via the transistors T1 and T2. An exciting current flows through the exciting coil 2a in the direction indicated by the solid line indicated by the symbol A in the direction of the arrow.

At this time, since the on-off valve 2 is in the open state, the open state is maintained even if the exciting current flows in the direction indicated by the solid line indicated by the reference symbol A. At this time, the microcomputer 1 sends out the valve opening signal for a short time from the output port 1c, and simultaneously sends the voltage detection command signal from the output port 1a for the same short time.

Immediately before the valve opening signal and the voltage detection command signal disappear, the microcomputer 1 reads the voltage detection signal from the voltage detection circuit 7 to determine whether or not the battery 6 has the valve driving capability. Thereafter, the valve opening signal and the voltage detection command signal disappear.

In determining the valve driving capability of the battery 6, the microcomputer 1 checks whether the state of the on-off valve 2 is open or closed by the signal output state to the valve control circuit 5. If this is the case, an "H" level valve closing signal is sent from the output port 1d of the microcomputer 1 to the transistor T7 and the inverter A2 for a short time.

Then, the transistors T7 and T3 are turned on, and the valve closing signal is inverted by the inverter A2 to turn on the transistors T8 and T4, so that the first battery 4 opens and closes the transistor via the transistors T3 and T4. Excitation current flows in the direction indicated by the dotted line indicated by the symbol B in the second excitation coil 2a.

At this time, since the on-off valve 2 is in the closed state, the closed state is maintained even if an exciting current flows in the direction indicated by the dotted line indicated by the symbol B. At this time, the microcomputer 1 sends the valve closing signal from the output port 1c for a short time, and simultaneously sends the voltage detection signal from the output port 1a for the same short time.

The microcomputer 1 reads the voltage detection signal from the voltage detection circuit 7 just before the valve closing signal and the voltage detection command signal disappear, and determines whether or not the battery 4 has the valve driving capability. Thereafter, the valve closing signal and the voltage detection command signal disappear.

As described above, in determining the valve driving ability of the battery 4, the microcomputer 1 determines whether the state of the on-off valve 2 is the open state or the closed state by the signal output state to the valve control circuit 5. After the confirmation, if the valve is in the open state, a valve opening signal is transmitted from the output port 1c for a short time and a voltage detection command signal is transmitted from the output port 1a for a short time.

The time width of the two signals depends on the output port 1 to open the on-off valve 2 when an emergency such as abnormal flow is eliminated.
c is set to be the same as the time width of the valve-opening signal sent out from c. Also, in order to determine the valve drive capability of the battery 6, as described above, the short time period during which the microcomputer 1 sends the valve closing signal and the voltage detection command signal from the output ports 1d and 1a, respectively, depends on the flow rate abnormality and the like. Is set to be the same as the time width transmitted from the output port 1d to close the on-off valve 2 in the event of an emergency.

In the above embodiment, the microcomputer 1, the shut-off valve control circuit 5, and the pull-up resistor R11 are connected to the second battery 6 independent of the first battery 4, so that the second battery Power is supplied from 6.

By doing so, the exciting coil 2 of the on-off valve 2
The microcomputer 1 and the valve control circuit 5 are prevented from being adversely affected by the temporary decrease in the terminal voltage of the first battery 4 caused by the flow of a large exciting current through the a.

[0039]

Since the gas meter according to the present invention is constructed as described above, a test current is supplied to the exciting coil of the valve built in the gas meter in determining whether the battery has the valve driving capability. Since the battery voltage at the time of the detection can be detected, the voltage can be accurately detected.

When the battery voltage is detected to determine the valve driving capability of the battery (4), the excitation coil (2) of the on-off valve (2) is detected.
Even if a test current flows in a), there is no possibility that the state of the on-off valve changes.

Further, unlike the prior art, there is no need for a pseudo resistor corresponding to the exciting coil or a special circuit for flowing a test current through this pseudo resistor, so that there is an advantage that the number of parts can be reduced.

[Brief description of the drawings]

FIG. 1 is a main part block diagram of an embodiment of the present invention.

FIG. 2 is a specific electric circuit diagram of the block diagram of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microcomputer 2 On-off valve 2a Excitation coil 3 Valve drive circuit 4 First battery 5 Valve control circuit 6 Second battery 7 Voltage detection circuit

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 000005234 Fuji Electric Co., Ltd. 1-1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Ikko Itsui 9-10 Misonodai, Fujisawa-shi, Kanagawa Prefecture (72) ) Inventor, Katsuto Sakai 3-2-7-13-123, Takasago, Katsushika-ku, Tokyo (72) Inventor, Satoshi Sato 2-11-2, Kajigaya, Takatsu-ku, Kawasaki-shi, Kanagawa (72) Inventor Shinichi Sato, Kitano, Hachioji-shi, Tokyo 543-15 Machi (72) Inventor Mitsuru Mitsuto Saito 2-70, Chinen 1-chome, Atsuta-ku, Nagoya City, Aichi Prefecture Inside (72) Inventor Tomio Uetono 1-70, Chinen 2-chome, Atsuta-ku, Nagoya City, Aichi Prefecture Inside Aichi Watch Electric Co., Ltd. (72) Takayuki Matsumoto, Inventor 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Ground Inside the Toshiba Yanagimachi Plant (72) Inventor Takeshi Numagami 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. No. 1 Inside Fuji Electric Co., Ltd.

Claims (2)

[Claims] A battery for a power supply, a solenoid valve for stopping gas supply, a valve drive circuit for closing a solenoid valve by temporarily supplying current from the battery to an exciting coil of the solenoid valve, In a gas meter having a microcomputer that supplies an exciting current from a battery to an electromagnetic valve via the valve drive circuit in the event of an emergency by judging a flow rate abnormality or the like, by temporarily passing a unidirectional driving current to the exciting coil (2a), The valve is brought into a closed state, the valve is kept closed even after the current is cut off, and the drive current is temporarily passed in the other direction to the exciting coil (2a), so that the valve is opened and the valve is opened even after the current is cut off. Self-holding on-off valve that maintains state (2)
A valve drive circuit (3) for supplying a drive current in one direction or a reverse direction to the excitation coil (2a); a valve control circuit (5) for controlling the valve drive circuit (3); And outputs a closing signal to close the on-off valve (2) in an emergency or the like to the valve control circuit (5) temporarily, and temporarily outputs an opening signal for opening the on-off valve (2) as necessary. A microcomputer (1) that outputs a voltage to the valve control circuit (5), and a voltage detection circuit that detects the voltage of the battery (4) and outputs a voltage detection signal to the microcomputer (1) when the battery voltage is less than a certain value. (7) In determining the valve drive capability of the battery, the microcomputer (1)
However, after confirming whether the state of the on-off valve (2) is the open state or the closed state by the signal output state to the valve control circuit (5), the valve-open signal is output if the valve is open, and the valve is closed if the valve is closed A valve signal is temporarily sent to the valve control circuit (5), and a voltage detection command signal for operating the voltage detection circuit (7) is sent out.
A gas meter for detecting whether a battery voltage is lower than a minimum drive voltage of an on-off valve (2). A first battery (4) for supplying a drive current to the on-off valve (2) via a valve drive circuit (3); a microcomputer (1); and a valve control circuit (5). 2. The gas meter according to claim 1, further comprising a second battery (6) for supplying power to the first battery (4), wherein the voltage detection circuit (7) detects the voltage of the first battery (4).