JPH1078342A - Gas meter - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a gas meter that can automatically return after confirming safety after a gas flow path is cut off. SOLUTION: A shut-off valve 13 which can be electrically driven bidirectionally is used as a means for shutting off a gas flow path (gas pipe 12). When the shut-off valve 13 is operated to cut off the gas flow path due to any abnormality, the control unit 20 sets the pressure switch 1
The state of the gas pressure drop on the downstream side is monitored by 5, and after confirming that there is no gas pressure drop abnormality due to gas leakage or the like, the shut-off valve 13 is automatically returned. This makes it possible to automatically return the gas meter while ensuring safety without bothering the user or the like. Since the pressure switch 15 is a method of outputting a detection signal only when the pressure falls below a predetermined set pressure, battery consumption is reduced as compared with a case where a pressure sensor which always needs to supply a drive current for pressure monitoring is used. Few.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas meter having a function of shutting off a gas flow path when any abnormality occurs.

[0002]

2. Description of the Related Art Some gas meters have a safety function of shutting off a gas flow path when an abnormality occurs using a microcomputer. Here, the abnormal time is when an earthquake exceeding a predetermined seismic intensity occurs, when an abnormal impact is applied to the gas meter for some reason, or when the gas supply pressure drops abnormally.

FIG. 8 shows a schematic configuration of a main part of a conventional gas meter. The gas meter includes a flow detector 310 for detecting a gas flow rate flowing through a gas flow path, a one-way valve 320 provided in a gas flow path on the upstream side of the flow detector 310, a flow detector 310 and a unidirectional valve. A safety function unit 330 connected to the valve 320 and controlling these operations;
An accumulator 340 connected to the flow detector 310 for accumulating the detected flow, a display 350 for displaying the result integrated by the accumulator 340, and a one-way valve 320 operating when any abnormality occurs to activate the gas flow. And an LED 360 for displaying a warning that the road has been interrupted.

Next, the operation of the gas meter shown in FIG. 8 will be described with reference to FIG. Normally, the flow detector 310 outputs a flow pulse proportional to the gas flow flowing through the gas flow path. The flow rate pulses are integrated by the integration unit 340 and displayed on the display unit 350. Here, when vibration or shock due to an earthquake or other causes, or abnormal decrease in gas supply pressure occurs, the safety function unit 330 drives the one-way valve 320 to close it, and shuts off the gas flow path (FIG. 9). Step S201). At this time, the LED 360 is turned on.

When the user notices that the valve is shut off by turning on the LED 360, the user presses a return shaft (not shown) provided outside the gas meter (step S20).
2). Thereby, the one-way valve 320 is once opened (step S203), and the gas flow path is opened. Next, the safety function unit 330 checks whether there is a flow pulse from the flow detection unit 310, and if there is a flow pulse (step S20).
4; Y), it is determined that there is gas use or gas leak on the downstream side, and the one-way valve 320 is closed again (step S20)
1). On the other hand, if there is no flow pulse after the interruption (step S204; N), it is confirmed whether or not the state continues for 2 minutes or more (step S205). As a result, when there is no flow pulse for 2 minutes or more (step S205; Y), it is determined that there is no abnormality such as gas leakage on the downstream side, and the gas meter is returned to the return state by maintaining the valve open state as it is. (Step S206).

[0006]

As described above, in a conventional gas meter provided with a safety function, a shutoff valve is electrically driven in response to an abnormal signal to shut off a gas flow path. In this shut-off valve, a unidirectional valve that can be electrically driven only in a direction in which the valve is closed is used. In order to return the gas flow path to the original open state, the valve is manually opened. Operation was required. For this reason, it does not return to the return state unless the user or the like notices the gas flow path cutoff state. In this case, the warning display LED 36
There is a problem in that 0 remains lit and battery consumption is accelerated.

Further, in the conventional gas meter, since the return operation by hand is indispensable, when the one-way valve 320 is actuated due to a factor other than the original abnormality (for example, a vibration due to a mere passing of a car). However, the user must perform a return operation every time, which is troublesome.
Furthermore, if the user does not know how to perform the return operation,
There was a problem that the service staff of the gas company had to be dispatched.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a gas meter that can automatically return after confirming safety after shutting off a gas flow path.

[0009]

According to a first aspect of the present invention, there is provided a gas meter provided in a gas flow path for measuring a gas flow rate, wherein the gas flow path is shut off and the gas flow path is opened. And a pressure detecting means for detecting a gas pressure in a gas flow path on the downstream side of the bidirectional shutoff valve when a predetermined abnormal situation occurs. While driving the bidirectional shutoff valve to the shutoff state, when the gas pressure below a predetermined set pressure is not detected by the pressure detecting means within a predetermined time after the bidirectional shutoff valve enters the shutoff state, Valve drive control means for driving the shut-off valve to return to the return state.

In this gas meter, even if the bidirectional shut-off valve shuts off the gas flow path due to the occurrence of some abnormality,
When it is confirmed that there is no abnormality such as a gas leak on the downstream side, the shut-off valve automatically returns.

According to a second aspect of the present invention, there is provided the gas meter according to the first aspect, wherein the pressure detecting means is provided only when the gas pressure in the gas flow path downstream of the bidirectional shutoff valve falls below a predetermined set pressure. This uses a pressure switch that outputs a detection signal. In this gas meter, the pressure switch as the pressure detecting means does not output a detection signal when the pressure is equal to or higher than the set pressure, and outputs a detection signal only when the pressure is equal to or lower than the set pressure. There is no need to constantly supply current.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic sectional configuration of a gas meter according to an embodiment of the present invention. This gas meter 10
Is a main body 11, an inlet portion 12A inserted into the main body 11 for receiving gas a, and an outlet portion 1 for discharging gas.
And a gas pipe 12 as a gas flow path having 2B. The gas pipe 12 includes, in order from the inlet 12A side, a shutoff valve 13 for shutting off a gas flow path in the event of an abnormality, a flow detection unit 14 for detecting a flow rate of gas flowing through the gas flow path,
When the internal pressure of the gas pipe obtained through the pressure introducing hole 17 provided in the gas pipe 12 on the downstream side of the flow rate detecting section 14 exceeds a predetermined pressure, the internal contact is closed and the set pressure detection signal is output. An output pressure switch 15 is provided. The main body 11 is further provided with a control unit 20 that receives the output signals of the flow rate detection unit 14 and the pressure sensor 15 and controls the shutoff valve 13. As the shutoff valve 13, a bidirectional shutoff valve that can electrically select a shutoff state in which the gas flow path is shut off and a return state in which the gas flow path is opened is used. As the flow detection unit 14, for example, a later-described membrane flow meter (FIG. 4) is used.

FIGS. 2 and 3 show the shut-off valve 13 in FIG.
FIG. 2 shows a reset state,
FIG. 3 shows a cut-off state. In the following description, the opening 12a in the gas flow path in the gas pipe 12 and the shutoff valve 1
The positional relationship of 3 will be described with the opening 12a on the upper side and the shutoff valve 13 side on the lower side.

The shut-off valve 13 has a housing 41 made of a magnetic material. The housing 41 is formed in a small-diameter cylindrical shape on the upper side and in a large-diameter cylindrical shape on the lower side,
The upper end is open and the lower end is closed. A flange portion 4 is provided outside a central portion of the housing 41 in the vertical direction.
2 is fixed. This flange portion 42 is fixed to the main body 11 in FIG. A cylindrical permanent magnet 43 is fixedly fitted on the inner surface side of the upper portion of the housing 41, and a coil 44 serving as an electromagnet is provided on the lower side of the housing 41. A plunger 45 is inserted in a hollow portion formed by the permanent magnet 43 and the coil 44 so as to be movable in the axial direction. This plunger 45
Has an upper magnetic portion 45a formed of a magnetic material and a lower nonmagnetic portion 45b formed of a nonmagnetic material.
The upper end of the plunger 45 projects from the upper end of the housing 41, and the upper end of the plunger 45 has an opening 12.
A rubber valve body 46 capable of closing a is attached. A spring 47 is provided between the rubber valve body 46 and the flange portion 42 to urge the rubber valve body 46 upward.

A current does not normally flow through the coil 44 of the shut-off valve 13. For this reason, as shown in FIG. 2, the magnetic force of the permanent magnet 43 acts as shown by an arrow 48, the plunger 45 is retracted, and the opening 12a is opened. As a result, gas can pass through the opening 12a as shown by the arrow 49. In order to bring the shut-off valve 13 into the shut-off state, as shown in FIG. 3, a current is passed through the coil 44 to generate a magnetic field that cancels out the magnetic field generated by the permanent magnet 43. The magnetic force generated by the coil 44 is represented by a dashed arrow 50.
Indicated by Then, the plunger 45 projects by the force of the spring 47, and the opening 12 a is closed by the rubber valve body 46. On the other hand, in order to bring the shut-off valve 13 into the return state, a current in a direction opposite to the direction in which the shut-off valve 13 is brought into the coil 44 is supplied to the coil 44 to generate a magnetic field that strengthens the magnetic field generated by the permanent magnet 43. As a result, the plunger 45 is retracted by overcoming the force of the spring 47, and as a result, the opening 12a is opened.

FIG. 4 shows a schematic cross-sectional configuration of the flow rate detector 14. Here, a case where a membrane flow meter is used will be described as an example. As shown in this figure, the flow detection unit 14 has a case main body 60, and a gas inlet 61 and a gas outlet 62 are provided on the upper part of the case main body 60. Further, a front weighing chamber 70 and a rear weighing chamber 80 are provided inside the case main body 60.

In the front weighing chamber 70, a membrane 71 is provided at the center in the front-rear direction (the left side in the figure is the front side), and a membrane plate 72 is attached to the membrane 71. Here, a space on the front side of the membrane 71 in the front measurement chamber 70 is defined as a chamber,
The space on the rear side is a room. In the upper part of the front weighing chamber 70,
A gas port 73 communicating with the chamber and a gas port 74 communicating with the chamber are provided. A blade shaft 76 is connected to the membrane plate 72 via a blade 75. The blade shaft 76 is configured to rotate with the movement of the membrane 71 in the front-rear direction. The blade shaft 76 penetrates through the front measurement chamber 70 and protrudes upward.

Similarly, in the rear measuring chamber 80, a membrane 81 is provided at the center in the front-rear direction, and the membrane 81 is provided with a membrane plate 82.
Is attached. Here, the space in front of the membrane 81 in the rear measurement chamber 80 is defined as a room, and the space on the rear side is defined as a room. A gas inlet / outlet portion 83 communicating with the chamber and a gas inlet / outlet portion 84 communicating with the chamber are provided at an upper portion of the rear measuring chamber 80. A blade shaft 86 is connected to the membrane plate 82 via a blade. The blade shaft 86 is configured to rotate with the movement of the film 81 in the front-rear direction. Wing shaft 8
The reference numeral 6 penetrates the rear measuring chamber 80 and projects upward.

A gas discharge pipe 63 is provided between the gas ports 73 and 74 and between the gas ports 83 and 84, respectively.
Are provided. This gas discharge pipe 63 is connected to the gas outlet 62. In addition, the gas entrance 7
Above 3, 74, a valve 64 is provided. The valve 64 can be moved in the left and right direction in the figure, and depending on its movement position, a state in which the gas inlet / outlet portions 73 and 74 are both closed, a state in which the gas inlet / outlet portion 73 communicates with the gas exhaust pipe 63, One of the states in which the part 74 communicates with the gas discharge pipe 63 can be selected. Similarly, a valve 65 is provided above the gas ports 83 and 84.
Is provided. The valve 65 can also move in the left-right direction in the figure, and depending on the movement position, a state in which the gas inlet / outlet portions 83 and 84 are both closed, a state in which the gas inlet / outlet portion 83 communicates with the gas exhaust pipe 63, Doorway 84
And the gas discharge pipe 63 can be selected from any state.

An upper arm 77 is connected to an upper end of the wing shaft 76, and an upper arm 87 is connected to an upper end of the wing shaft 86.
These elbows 77 and 87 are fixed to the adjusting plate 9 by pins 91.
2 are connected. The adjusting plate 92 has the crankpin 9
3, the crank arm 94 and the valve arm 95,
96 are connected. The crank arm 94 is connected to a crank shaft 97, and rotates the crank shaft 97. Valve arms 95, 96 are connected to valves 64, 65, respectively, and these valves 64, 6
5 is moved left and right in the figure. A worm 98 and a worm wheel 99 are provided on the crankshaft 97.
, A disc (not shown) is attached, and this is shown in FIG.
1 rotates in accordance with one cycle of the flow meter shown in FIG. A plurality of magnets are attached to this disk at equal intervals along the circumferential direction, and the rotation speed of the disk is detected by a magnetic sensor disposed at a position capable of facing these magnets. Has become.

Here, an outline of the operation of the membrane type flow meter shown in FIG. 4 will be described with reference to FIG. The introduction of gas into and out of the measuring chambers 70 and 80 is performed by the interlocking action of the valves 64 and 65 and the membranes 71 and 81. The driving force for the movement of the membranes 71, 81 is the gas pressure difference between the gas inlet 61 and the gas outlet 62.
In the state shown in FIG. 5A, the valve 64 closes both the gas ports 73 and 74, and the valve 65 communicates the gas port 83 with the gas discharge pipe 63. In this state,
The gas entering the chamber from the gas inlet / outlet section 84 pushes the membrane 81 toward the chamber by a pressure difference, and the gas in the chamber is discharged from the gas outlet section 62 through the gas inlet / outlet section 83, the valve 65 and the gas exhaust pipe 63 in this order. You. The movement of the membrane 81 is controlled by the blade shaft 86, the elbow metal 87, the adjustment plate 92, and the valve arms 95 and 96.
5 in sequence, and as shown in FIG.
4 is moved to a state where the gas port 74 and the gas discharge pipe 63 communicate with each other, and the valve 65 is moved to a state where both the gas ports 83 and 84 are closed. At this time, the gas in the room is supplied to the gas port 73, the valve 64,
The gas passes through the gas discharge pipe 63 in order and is discharged from the gas outlet 62. In the same manner, the movement of returning to the state of FIG. 5A through the states of FIGS. 5C and 5D is repeated.

With the above movement, the crank arm 94 and the crank shaft 97 rotate. The rotation of the crankshaft 97 rotates the above-mentioned disk (not shown) via the worm 98 and the worm wheel 99. The rotation of the disk is detected by the above-described magnetic sensor (not shown), and the sensor output is output as a flow rate pulse as a flow rate calculation unit 21 described later.
(FIG. 6).

FIG. 6 shows the configuration of the control unit 20 and its peripheral parts in FIG. As shown in this figure, the gas meter 10 further includes a display unit 25, and the control unit 20 is connected to the shut-off valve 13, the flow detection unit 14, the pressure switch 15, and the display unit 25. Control unit 20
A flow rate calculating unit 21 for calculating a flow rate based on an output signal of the flow rate detecting unit 14, an integrating unit 22 for calculating an integrated flow rate by integrating the flow rates calculated by the flow rate calculating unit 21; , Flow calculation unit 21 and pressure switch 15
Safety function unit 23 that detects an abnormality based on each output signal of
And a shutoff valve drive circuit 24 that drives the shutoff valve 13 under the control of the safety function unit 23. Safety function part 2
3 and the shut-off valve drive circuit 24 correspond to the valve drive control means in the present invention. The flow rate calculation unit 21, the integration unit 22, and the safety function unit 23 are configured by, for example, a microcomputer.

The integrated flow rate calculated by the integrating section 22 is displayed on the display section 25. The safety function unit 23 controls the shut-off valve drive circuit 24 in the event of an abnormality such as when an earthquake or shock exceeding a predetermined seismic intensity is detected by the above-mentioned seismic sensor or when the gas supply pressure falls below a predetermined value. The shutoff valve 13 is driven to cut off the gas flow path, and an alarm display such as blinking of an LED (light emitting diode) is displayed on the display unit 25.

Next, the operation of the gas meter configured as described above will be described with reference to FIG.

Normally, the flow rate detecting section 14 outputs a flow rate pulse proportional to the gas flow rate flowing through the gas flow path and inputs the pulse to the flow rate calculating section 21. The flow rate calculator 21 calculates the gas flow rate based on the flow rate pulse from the flow rate detector 14. The calculated gas flow rates are integrated by the integration unit 22 and displayed on the display unit 350. Here, when vibration or shock due to an earthquake or other causes, or abnormal decrease in gas supply pressure, etc., occur, the safety function unit 23 drives the shut-off valve 13 to open the opening 12.
a to close the gas flow path (step S10 in FIG. 7).
Along with 1), the LED of the display unit 25 is turned on to display a warning.

After the gas flow path is shut off, the safety function unit 23 starts monitoring whether or not there is a set pressure detection signal from the pressure switch 15 (step S102). This monitoring is, for example, 1
It is performed at regular intervals at time intervals of less than seconds. Then, when the set pressure detection signal is not input from the pressure switch 15 (Step S103; N), such monitoring is continuously performed for a certain period of time. As a result, when the set pressure detection signal is not input from the pressure switch 15 for a certain period of time or more (step S104; Y), it is determined that there is no gas use or gas leak downstream of the shutoff valve 13, and the shutoff is performed. The shutoff valve 13 is opened by the valve drive circuit 24 to return to the return shutoff (step S105).

On the other hand, after the gas flow path is cut off, the pressure switch 1
When the set pressure detection signal is input from Step 5 (Step S103; Y), it is determined that there is gas use or gas leakage downstream of the shut-off valve 13, and the shut-off valve 13 is kept closed. Then, the process waits for a return operation by a person (step S107).

As described above, in the present embodiment, the shutoff valve 13 that can be electrically driven bidirectionally is used as a means for shutting off the gas flow path (gas pipe 12), and the gas flow path is changed due to occurrence of some abnormality. When the shutoff valve 13 is shut off, the state of the gas pressure drop on the downstream side is monitored thereafter, and after confirming that there is no gas pressure drop abnormality due to gas leakage or the like, the shutoff valve 13 is automatically returned. In addition, the gas meter can be automatically reset while ensuring safety without bothering the user or the like. In particular, in the present embodiment, a pressure switch that outputs a detection signal only when the pressure falls below a predetermined set pressure is used.Therefore, a pressure sensor that must constantly supply a drive current for pressure monitoring is used. Battery consumption can be reduced as compared with the case where the battery is used.

As described above, the present invention has been described with reference to some embodiments. However, the present invention is not limited to these embodiments, and can be variously modified within an equivalent range. For example, in the present embodiment, the flow rate detector 14 is described by taking a membrane flow meter as an example, but may be another type of flow meter (fluidic flow meter, thermal flow meter, or the like).

Although the pressure switch 15 described in the present embodiment may be newly provided, an existing pressure switch conventionally provided for monitoring the gas supply pressure may be used. You may. However, in this case, since the gas pressure set for monitoring the gas supply pressure is usually a considerably low value, if this set value is used as it is, the “constant time” in step S104 of FIG. Therefore, it is difficult to perform quick processing after the gas flow path is cut off. Therefore, separately from the low set pressure for monitoring the gas supply pressure, a configuration is adopted in which a higher set pressure used for determining whether to return to the return state (step S104 in FIG. 7) can be set to the same pressure switch. It is desirable to do.

[0033]

As described above, according to the gas meter of the first or second aspect, the two-way shut-off valve is used as the means for shutting off the gas flow path, and the gas flow path is cut off by the occurrence of some abnormality. In such a case, after confirming that there is no abnormality such as gas leakage on the downstream side after that, the two-way shutoff valve was automatically returned, so
There is an effect that the gas meter can be automatically reset while ensuring safety without bothering the user or the like, and the number of times the gas company is dispatched to return the gas meter can be drastically reduced.

According to a second aspect of the present invention, there is provided the gas meter according to the first aspect, wherein the pressure detecting means is provided only when the gas pressure in the gas flow path downstream of the bidirectional shutoff valve falls below a predetermined set pressure. This uses a pressure switch that outputs a detection signal. In this gas meter, the pressure switch as the pressure detecting means does not output a detection signal when the pressure is equal to or higher than the set pressure, and outputs a detection signal only when the pressure is equal to or lower than the set pressure. There is no need to constantly supply current. Therefore, there is an effect that the consumption of the battery can be reduced as compared with a case where a pressure sensor which always needs to supply a drive current for monitoring pressure is used.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a main part of a gas meter according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a shutoff valve in a return state (valve open state).

FIG. 3 is a cross-sectional view illustrating a schematic configuration of a shutoff valve in a shutoff state (valve closed state).

FIG. 4 is a cross-sectional view illustrating a schematic configuration of a membrane flow meter as an example of a flow detection unit.

FIG. 5 is an explanatory diagram for explaining the operation of the flow rate detection unit.

FIG. 6 is a block diagram illustrating a configuration of a control unit and a peripheral unit thereof.

FIG. 7 is a flowchart for explaining the operation of the gas meter.

FIG. 8 is a block diagram illustrating a schematic configuration of a conventional gas meter.

FIG. 9 is a flowchart for explaining the operation of a conventional gas meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body 12 Gas pipe 13 Shutoff valve 14 Flow rate detection part 15 Pressure switch 20 Control part 21 Flow rate calculation part 22 Integration part 23 Safety function part 24 Shutoff valve drive circuit 25 Display part

Claims (2)

[Claims] 1. A gas meter disposed in a gas flow path for measuring a gas flow rate, wherein both a cut-off state for cutting off the gas flow path and a return state for opening the gas flow path are electrically selectable. A two-way shut-off valve, pressure detecting means for detecting a gas pressure in a gas flow path on the downstream side of the two-way shut-off valve, and driving the two-way shut-off valve to shut off when a predetermined abnormal situation occurs. On the other hand, when a gas pressure lower than a predetermined set pressure is not detected by the pressure detecting means within a certain period of time after the bidirectional shutoff valve is set to the shutoff state, the valve drive for driving the bidirectional shutoff valve to return to a reset state is performed. A gas meter comprising control means. 2. The pressure sensor according to claim 1, wherein the pressure sensor is a pressure switch that outputs a detection signal only when a gas pressure in a gas flow path downstream of the bidirectional shutoff valve falls below the predetermined pressure. The gas meter according to claim 1, wherein