JP2004309159A - Gas meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas meter capable of freely adapting to conditions of various different underlaid pipes of consumers and safely starting to supply gases. <P>SOLUTION: The gas meter comprises a shut-off valve arranged between a pipe on the side of gas supply and a secondary-side pipe; a flow sensor installed to the secondary-side pipe of the shut-off valve; a pressure sensor; and a controller for measuring a flow signal transmitted from a measuring sensor and closing the shut-off valve when the quantity of flow is anomalous. The function of estimating the capacity of the secondary-side pipe by tentatively closing the shut-off valve 8 to cut off a gas circuit, then opening the shut-off valve, and measuring the pressure recovery time and pressure recovery flow required for the recovery of pressure and storing the pressure recovery time, the pressure recovery flow, and the capacity of the secondary-side pipe; the function of detecting gas leakage etc. from the secondary-side pipe; and other functions are incorporated to the controller 2 as software. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas meter attached to a gas pipe in a general household or the like to measure a gas flow rate.
[0002]
[Prior art]
FIG. 1 is a block diagram showing a configuration of a gas pipe and a gas meter.
The gas pipe is divided into a gas supply pipe 14 and a secondary pipe 15 with the cutoff valve 8 as a boundary, and a gas metering sensor 10 and a pressure sensor 9 are installed after the cutoff valve 8. The gas appliance 13 is connected to the secondary pipe 15.
The shutoff valve 8, the pressure sensor 9, and the gas metering sensor 10 are components of the gas meter 1. In addition, the gas meter 1 receives a pressure signal and a flow rate signal of the gas transmitted by these sensors through the input circuits 4 and 6, controls the microprocessor 3 and the shut-off valve 8 which process these and output an appropriate control signal. And a controller 2 having an output circuit 5 for performing the operation.
[0003]
The microprocessor 3 can also receive sensor signals from the gas leak alarm 12 and the vibration sensor 11 through the input circuit 4 as appropriate in addition to the above sensors, process them, and output them according to programmed criteria. A signal is output to the output circuit 5 so that the shutoff valve 8 can be controlled. Software for processing, determination, output, and the like is incorporated in the microprocessor 3.
The gas metering sensor 10 emits a flow pulse for each unit volume, and the controller detects the flow pulse. For example, when the microprocessor 3 determines that the flow rate signal from the gas metering sensor 10 is an abnormal flow rate, it outputs a command to close the shutoff valve 8 through the output circuit 5 and stops the supply of gas to the secondary side. The gas meter 1 has a security function such as performing a security function.
[0004]
When the gas can be used normally from the closed state of the shut-off valve, the shut-off valve is first opened and the signal of the gas metering sensor 10 is checked. If there is no flow within a certain period of time from the time of opening, it is determined that the plug of the gas appliance connected to the secondary side is closed, and the opening is maintained and the gas can be used normally. ing. If the flow rate is within a certain period of time, it is determined that the gas appliance is in a state of disappearance, that is, there is a risk of leakage of raw gas from the gas appliance, and the shutoff valve is closed.
Also, shutoff valves, which occupy a large number in the market, once closed by a signal from the controller, maintain the closed state by the force of a spring, and when the shutoff valve is opened, the gas flow path is in front of the gas meter. It is necessary to change from the closed state to the open state by operating the sealed return rod.
[0005]
The controller built in the gas meter is provided with a reed switch 7 as an input means for realizing a function for closing the shut-off valve on a test basis. When the reed switch 7 is turned on by a magnet, the controller turns on the shut-off valve. Close the cap. Once the shut-off valve is closed by the output from the controller, the shut-off valve is kept closed by the force of the spring. When the shut-off valve is opened, the shut-off valve is used to change from the closed state to the open state by operating the return rod which is sealed from the gas flow path in front of the gas meter. In general, the controller monitors the voltage generated from the coil caused by the operation of the plunger of the shut-off valve at the time of return, and detects that the shut-off valve has been opened. I have. This will be referred to as a return input in the following gas meter flowchart.
[0006]
FIG. 6 is a flowchart of the operation of the conventional gas meter.
After the return input of step S34, that is, opening of the shut-off valve from the shut-off state of shut-off of the shut-off valve in step S33 (hereinafter, step is omitted), it is determined in S35 that the pressure is recovered. If the pressure on the secondary side has recovered in S35, it is confirmed that there is no flow pulse for a certain period of time determined in S36 and S37, and the leak test in S33 has been completed. That is, it is confirmed that the plug of the gas appliance is closed in the processing of S36 and S37, and the gas is put into a state where it can be used normally.
If the pressure has not recovered in S35, for example, three minutes have elapsed since the opening of the shut-off valve in S38, and if the pressure still did not recover, the shut-off valve in S39 was closed to bring it into a shut-off state.
[0007]
In this way, immediately after opening, even if the plug of the gas appliance is stopped, there is a pipe capacity of the secondary gas pipe, and the gas flows by the secondary pipe capacity. Is not determined as an abnormal flow rate.
Furthermore, in order to correspond to all of the various secondary pipe capacities for each customer, assuming the maximum pipe length that can be estimated, based on the maximum pipe capacity, the time until the pressure recovery at the time of plug opening is determined. In consideration of the supply capacity, for example, it is uniquely determined to be, for example, 3 minutes, and if the pressure does not recover until 3 minutes after opening, the controller determines that there is an abnormality and shuts off.
[0008]
When the gas cannot be supplied due to an abnormality on the supply side, the pressure has decreased, but the controller can detect the decrease in the pressure by a signal from the pressure sensor.
If the gas is not used even in this state of pressure drop, that is, if the controller does not detect a flow signal, the shut-off valve will not be closed, but if there is a flow rate, the gas appliance when there is no gas supply capacity The controller is designed to close off the shut-off valve when there is concern about the release of raw gas from the gas appliance into the atmosphere as a use of a gas appliance. However, also in this case, similarly, in consideration of the fact that gas flows by the pipe capacity of the secondary pipe when the supply abnormality is released and the gas can be supplied, the controller determines the flow rate during the pressure recovery determination. The operation is such that the flow rate is not determined to be abnormal as the gas filling of the secondary side pipe and is not interrupted.
[0009]
[Patent Document 1]
JP-A-8-278170 (page 3-4, FIG. 1)
[Patent Document 2]
JP-A-8-278171 (page 3-4, FIG. 1)
[0010]
[Problems to be solved by the invention]
As described above, when opening the shut-off valve so that the gas can be used, it is determined that there is no fixed amount of flow in order to prevent the gas appliance from being opened in the use state. Since there is a pipe capacity of a gas pipe and a gas filling the pipe flows into the pipe, a leak inspection of a gas appliance is performed by detecting a flow rate for a certain time after waiting for pressure recovery.
However, since the pipe capacity on the secondary side differs depending on the laying condition of the pipes of each customer for pressure recovery, the maximum pipe capacity that can take into account the time required for pressure recovery and the various supply capacities differ from the maximum capacity. By estimating the time, for example, it was uniquely determined to be 3 minutes.
[0011]
In this case, even if the customer has a small pipe capacity, the pressure recovery time according to the above-mentioned maximum pipe capacity is applied until pressure recovery, so if the shut-off valve is opened, For example, even though the time to pressure recovery is short, the controller does not close the shut-off valve until the time of pressure recovery according to the maximum piping capacity described above, so the gas appliance is open. At that time, raw gas is released from the gas appliance into the atmosphere. The same can occur during recovery after the gas supply capacity on the supply side has been lost.
To solve such a problem, a method has been proposed in which a supply gas pressure fluctuation device is added to a gas meter to estimate the supply gas pressure capacity on the secondary pipe side (Japanese Patent Application Laid-Open No. 7-27591). However, in this proposal, the target gas appliances are limited to those with a governor, and cannot be applied to gas appliances without a governor. The cost increases because the supply gas pressure fluctuation device is added.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to provide a gas meter which can freely respond to various conditions of laying piping of each customer and can start supplying gas safely even to a gas appliance having no governor. .
[0013]
[Means for Solving the Problems]
In order to achieve the object of the present invention, at least a shutoff valve arranged between a gas supply side pipe and a secondary side pipe, a flow sensor and a pressure sensor installed in a secondary side pipe of the shutoff valve are provided. A gas meter having a controller that measures a flow signal transmitted from a metering sensor of the gas meter and closes a shutoff valve when an abnormal flow rate flows. After shutting off, the shut-off valve is opened, and the pressure recovery time and the pressure recovery flow required until the pressure recovers are measured to estimate the secondary-side piping capacity, and the pressure recovery time, the pressure recovery flow and It is assumed that the function of storing the secondary pipe capacity is incorporated as software.
[0014]
After the shut-off valve is closed according to the abnormal flow rate by the flow sensor or the input signal from the external sensor, when the shut-off valve is opened, the time until the pressure recovers is determined as the pressure recovery time by the controller. If the time is equal to or greater than the sum of the spare times, the function of closing the shut-off valve and prohibiting the use of gas may be incorporated as software.
After the shut-off valve is closed by the abnormal flow rate by the flow sensor or the input signal from the external sensor, when the shut-off valve is opened, within the time until the pressure is recovered, the controller sets the pressure recovery flow rate and It is preferable that a function of closing the shut-off valve and prohibiting the use of gas when the gas flow signal is equal to or more than the sum of the predetermined marginal flow rates is incorporated as software.
[0015]
The controller is capable of supplying gas from a state in which gas cannot be supplied due to an abnormality on the supply side, that is, in the process of restoring the pressure on the supply side, within the time until the pressure recovers, the pressure recovery flow rate When the gas flow rate is equal to or more than the sum of the predetermined marginal flow rate and the gas flow rate, the function of closing the shut-off valve may be incorporated as software.
According to the present invention, since the secondary pipe capacity can be estimated and the pressure recovery time, the pressure recovery flow rate, and the secondary pipe capacity can be stored, these data can be used for detecting an abnormality in the gas pipe. Can be used.
[0016]
Further, when the time until the pressure recovers when the shut-off valve is opened is equal to or longer than the sum of the pressure recovery time and a predetermined margin time, the shut-off valve is closed to prohibit the use of gas. Thus, the safety of the gas pipe can be maintained with higher accuracy than before.
Similarly, after the shut-off valve is closed, when the shut-off valve is opened, within the time until the pressure recovers, a flow signal of the gas equal to or more than the sum of the pressure recovery flow rate and the predetermined margin flow rate is output. When the measurement is performed, the shut-off valve is closed to prohibit the use of gas, so that the safety of the gas pipe can be maintained with higher accuracy than in the past even for gas appliances without a governor.
Further, since these functions are improved only by incorporating software, the volume of the gas meter does not increase and the cost can be kept low.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to examples.
Example 1
The gas meter emits a flow pulse for each unit volume of gas flow, and the controller detects this flow pulse.For example, if there is a specified flow pulse within a certain time, the abnormal gas is used, that is, the abnormal flow rate As detection, a closing command is issued to the shutoff valve, and the shutoff valve is closed.
When the shut-off valve in the gas meter is opened from a state where there is no gas in the secondary pipe, the pressure in the secondary pipe rises and reaches the pressure on the supply side, and becomes a constant value. FIG. 2 is a graph showing the time course of the pressure in the secondary pipe after the shutoff valve is opened. The signs of the curves correspond to the secondary piping volumes, ie, 10, 20 and 30 liters. If the supply capacity on the supply side is the same when the shut-off valve is opened, the pressure increases faster as the secondary-side piping capacity is smaller. The flow rate flowing from the supply side to the secondary side up to a certain pressure is always constant if the initial pressure conditions and the pipe capacity of the supply side and the secondary side are the same.
[0018]
In using the gas meter according to the present invention, after laying the piping, first storing the secondary-side piping capacity in the controller is performed. FIG. 3 is a flowchart at the time of measuring the pipe capacity of the gas meter according to the present invention.
First, software is installed in the controller so as to store the secondary-side piping capacity when the shut-off valve is opened after the reed switch input is continuously input as shown in S2 and S3.
Thereafter, the gas meter installation worker temporarily removes the gas pressure on the secondary side by opening the gas appliance in a state where the shut-off valve is closed in S4 to reduce the pressure in the secondary side pipe to the atmospheric pressure. And the same as
[0019]
Thereafter, the shutoff valve is opened. The controller monitors the voltage generated from the coil by operating the plunger of the shut-off valve when the shut-off valve is opened, detects that the shut-off valve has been opened, and can determine the return input. I have.
The controller, which has determined the return input in S5, measures the time t0 until the pressure is recovered in S6, S7, and S8 and the number n0 of the flow rate pulses of the gas flowing until the pressure is recovered in S8. If there is no flow pulse for a certain period of time at equivalent S9 and S10, it is determined that there is no leakage from the gas appliance, and the gas is normally used. At this time, the previously measured t0 and n0 are registered in S11.
[0020]
On the other hand, if there is a flow pulse within a certain period of time in S9 and S10, it is determined that there is a leak from the gas appliance in S13, and the shutoff valve is closed to be in the cutoff state. Since there is a leak, the measured time t0 and the flow pulse number n0 are different from the measurement of the secondary-side piping capacity, so that t0 and n0 measured in S14 are discarded and registration is not performed. Since the installation worker can determine that registration of t0 and n0 has failed due to the interruption in S13, the installation worker performs inspection and maintenance and attempts registration in the same procedure.
Example 2
After the registration, for example, when the abnormal flow rate is detected, a closing command is issued to the shut-off valve, and when the shut-off valve is opened after the shut-off state, the time t0 and the pressure until the pressure recovery stored in the flowchart of FIG. A leak test after opening is performed based on the number n0 of flow rate pulses of the gas flowing until recovery. FIG. 4 is a flowchart in the leak test of the gas meter according to the present invention.
[0021]
After opening the shut-off valve from the shut-off state (S16, S17), a time t0 + t1 obtained by adding a margin time t1 in consideration of the resolution of the measuring function and an error in the time measurement to the time t0 until the pressure is recovered in S22. The flow is measured at S20 and S21, and the flow rate at S18 is measured. In step S19, it is determined whether or not there is a flow pulse within the time t0 + t1 which is equal to or more than n0 + n1 obtained by adding the flow rate pulse n0 required before the pressure recovery and the surplus flow rate n1 in consideration of the resolution and the measurement error of the measuring function. If there is a flow pulse, it is determined that the plug of the gas appliance connected to the secondary side is not closed, and it is determined that there is a leak, and the shutoff valve is closed in S25.
[0022]
Also, based on the time measurement in S20, it is determined in S21 whether or not the time t0 + t1 has elapsed since the opening of the shut-off valve. If the pressure has not recovered by this time, it is determined that there is an equivalent leak, and the shut-off valve is closed in S25. And shut off.
Example 3
This is a case where the supply capability returns after the supply capability of the gas is lost on the supply side.
FIG. 5 is a flowchart when the supply capacity of the supply side of the gas meter according to the present invention returns.
When the gas supply capacity is lost, the pressure drops as shown in S27. This can be determined by the controller detecting the signal of the pressure sensor in the gas meter.
[0023]
The controller measures the flow rate pulse from the time when the pressure drops to the pressure recovery state (S30) in S28, and when the measured flow rate pulse becomes n0 + n1 or more (S29), the secondary side piping capacity or more. The gas appliance is used after the state of S27 in which the flow rate of the gas has flown, that is, the gas supply capability has been lost, and thereafter, the raw gas is released into the atmosphere from the gas appliance which is still open after the supply side pressure is restored. In step S31, the shutoff valve is closed to set the shutoff state.
If the flow rate pulse measured in S28 is n0 + n1 or less and the recovery of the pressure in S30 is detected, it is determined that the gas supply has been restored to normal, and the S32 pressure drop monitoring state is ended, that is, the gas can be used normally. And
[0024]
【The invention's effect】
According to the present invention, a gas meter having a controller that measures a flow signal transmitted from a metering sensor of a gas meter and closes a shut-off valve when an abnormal flow rate flows, in the controller, test-closes the shut-off valve. After shutting off the gas circuit, open the shut-off valve, measure the pressure recovery time and pressure recovery flow required until the pressure recovers, estimate the secondary side piping capacity, and recover the pressure recovery time and pressure recovery. Since the function of storing the flow rate and the pipe capacity on the secondary side is incorporated as software, it is possible to monitor the time until the pressure recovery and the flow rate until the pressure recovery at the time of opening from the closed state, and for each customer. Even if the conditions for laying the piping are different, it is possible to appropriately determine the leak from the gas appliance.
[0025]
Further, the present invention can be constructed by software based on the conventional configuration, so that there is no increase in cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a gas pipe and a gas meter. FIG. 2 is a graph showing a time course of pressure in a secondary pipe after opening of a shutoff valve. FIG. 3 is a pipe capacity of a gas meter according to the present invention. FIG. 4 is a flowchart of a gas meter leakage inspection according to the present invention. FIG. 5 is a flowchart of a gas meter according to the present invention when the supply capacity on the supply side is returned. FIG. 6 is an operation of a conventional gas meter. Flow chart [Explanation of reference numerals]
DESCRIPTION OF SYMBOLS 1 Gas meter 2 Controller 3 Horizontal part 4 Input circuit 5 Output circuit 6 Flow rate input circuit 7 Reed switch 8 Shut off valve 9 Pressure sensor 10 Gas metering sensor 11 Seismic sensor 12 Alarm device 13 Gas appliance 14 Supply side piping 15 Secondary side piping

Claims (4)

At least a shut-off valve disposed between the gas supply-side pipe and the secondary-side pipe, a flow sensor and a pressure sensor installed on the secondary-side pipe of the shut-off valve, and transmitted from the gas meter's metering sensor. In a gas meter having a controller that measures a flow signal and closes a shutoff valve when an abnormal flow rate flows, the controller includes a test shutoff of a shutoff valve and shutting off of a gas circuit, and then opening of a shutoff valve. A function of estimating the secondary pipe capacity by measuring the pressure recovery time and the pressure recovery flow required until the pressure is recovered, and storing the pressure recovery time, the pressure recovery flow, and the secondary pipe capacity. A gas meter characterized in that is incorporated as software. After the shut-off valve is closed according to the abnormal flow rate by the flow sensor or the input signal from the external sensor, when the shut-off valve is opened, the time until the pressure recovers is determined as the pressure recovery time by the controller. 2. The gas meter according to claim 1, wherein a function of closing the shut-off valve and prohibiting the use of gas when the time is equal to or longer than the sum of the spare time is installed as software. After the shut-off valve is closed by the abnormal flow rate by the flow sensor or the input signal from the external sensor, when the shut-off valve is opened, within the time until the pressure is recovered, the controller sets the pressure recovery flow rate and 3. The function according to claim 1, wherein a function of closing the shut-off valve and prohibiting the use of the gas when the flow signal of the gas equal to or more than the flow rate of the sum of the predetermined marginal flow rates is measured is incorporated as software. The described gas meter. The controller is capable of supplying gas from a state in which gas cannot be supplied due to an abnormality on the supply side, that is, in the process of restoring the pressure on the supply side, within the time until the pressure recovers, the pressure recovery flow rate The gas meter according to any one of claims 1 to 3, wherein a function of closing a shut-off valve when measuring a gas flow rate equal to or more than the sum of the predetermined marginal flow rate and the flow rate is incorporated as software. .

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