JP2013164327A - Gas meter mounted with acceleration sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology relating to a gas meter mounted with a three-axial direction acceleration sensor, in particular capable of quantitatively determining an inclination of a gas meter due to the occurrence of an earthquake.SOLUTION: In the case that absolute values of differences between an offset value after an earthquake and an initial offset value are respectively equal to or lower than a prescribed threshold, it is determined that there is no meter inclination due to the earthquake or that the meter inclination can be ignored, and a meter service is continued. If an offset ratio exceeds the threshold, it is determined that the inclination of a pipeline due to the earthquake or the inclination of the entire ground is abnormal, and meter cutoff is performed by closing a cutoff valve. An alarm lamp is simultaneously turned on in an alarm display part 9.

Description

  The present invention relates to a gas meter, and more particularly to a gas meter equipped with a triaxial acceleration sensor.

  Conventionally, an iron ball contact-type seismic intensity switch has been used as a gas meter shut-off device when an earthquake occurs (for example, Patent Document 1). As shown in FIG. 6, the seismic intensity switch 100 houses a ball 103 on a concave conical inner bottom surface 102 in a box 101 so as to roll freely. In a normal state, the ball 103 is held in the center of the inner lid 104 so as to be slidable in the vertical direction, and the ball 103 is pressed downward by its own weight, and the plunger 108 integrated with the disk 105 is lowered, and the switch The mechanism 106 and the contact 107 are turned off.

  When the box 101 vibrates due to an earthquake or the like, the ball 103 rolls from the center to the end, and accordingly, the plunger 108 is pushed upward to turn on the contact 107 and operate the shut-off valve (not shown). Let

  In the seismic intensity switch 100 method, there is a problem that discrimination between seismic motion and impact motion is unclear, and a gas meter equipped with a triaxial acceleration sensor has also been proposed (for example, Patent Document 2).

Japanese Utility Model Publication No. 61-48634 JP-A-9-145444

The gas meter is required to be installed in an upright state with no inclination, and the level is confirmed by a level when the gas meter is installed.
Moreover, even if it is attached in an upright state at the time of installation, an inclination may occur due to an earthquake or the like after installation. In particular, if the entire ground around the meter is significantly tilted due to an earthquake or the like, there may be a problem such as a crack in the underground piping. Restoring is a security issue.

  However, conventionally, there is no means for quickly determining such a state, and only visual confirmation at the time of meter reading has been stopped. Further, Patent Documents 1 and 2 do not disclose anything about the correspondence of this problem.

The inventors of the present application have completed a technique for solving the above problems by using an acceleration sensor mounted on a gas meter. The gist of the present invention is as follows. That is, the acceleration sensor-equipped gas meter according to the present invention is
(1) A gas meter equipped with a triaxial acceleration sensor and having a function of shutting off the meter based on seismic intensity judgment,
Means for obtaining an initial offset value (θ = θ ₀ , φ = φ ₀ ) in the three-axis directions based on an acceleration value measured by the acceleration sensor when the gas meter is installed;
Means for obtaining an offset value (θ = θe, φ = φe) after the end of the earthquake at the time of the occurrence of an earthquake in service of a gas meter;
Means for determining the amount of change from the initial offset value of the offset value after the end of the earthquake;
Means for shutting off the supply of the gas meter when the fluctuation amount exceeds the first threshold (ε1, ε2);
It is characterized by comprising.
However, the triaxial component of the gravitational acceleration G is Gx, Gy, Gz

  In the present invention, it is possible to appropriately select whether to use an arc tangent value and / or an arc sine value and an arc cosine value for the offset value φ.

(2) The invention of the above (1) is characterized by further comprising means for issuing an alarm when the initial offset value exceeds the second threshold value (α0).

(3) In each of the above inventions, when the safety of the piping system is confirmed after the end of the earthquake, an automatic return function for automatically returning the shut-off meter is further provided, and
The apparatus further comprises means for not operating the automatic return function when the fluctuation amount exceeds the first threshold value.

  According to the present invention, since the inclination of the gas meter can be obtained and monitored quantitatively, there is an effect that it is possible to optimize the construction at the time of installation.

  In addition, it can be detected even when the gas meter is tilted after an earthquake, particularly when the entire ground is tilted in the vicinity, which is difficult to determine visually. Thereby, there is an effect that it is possible to determine the risk of cracks in the underground piping from the ground.

  Further, in the invention in which the operation of the automatic return function is stopped based on the fluctuation amount, the automatic return function is not operated when there is a danger such as a crack in the underground pipe, so that the safety can be further improved. There is an effect.

It is a figure which shows the control block structure of the acceleration sensor mounting gas meter 1 which concerns on 1st embodiment. It is a figure which shows the method of calculating | requiring triaxial direction offset value (theta) and (phi) of a gravitational acceleration. It is a figure which shows the meter inclination determination flow in 1st embodiment. It is a figure which shows the meter inclination determination flow in 2nd embodiment. It is a figure which shows the meter inclination determination flow in 3rd embodiment. It is a figure which shows the structure of the conventional gas meter interruption | blocking apparatus 100. FIG.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to FIGS. Needless to say, the scope of the present invention is described in the claims and is not limited to the following embodiments.

  <First embodiment>

  Referring to FIG. 1, an acceleration sensor-equipped gas meter 1 includes a flow rate sensor 4 that is disposed in a gas flow path 5 in a housing 1 a and measures a gas usage amount of a consumer, and a pressure measurement in the gas flow path 5. A pressure sensor 7 for shutting off, a shutoff valve 6 for shutting off gas supply in an emergency, an acceleration sensor 3 for detecting an earthquake and a tilt of a meter, and a usage amount display unit 9 for displaying a gas usage amount of a consumer The alarm display unit 8 that issues an alarm when the inclination of the meter exceeds a threshold that will be described later, and the control unit 2 that sends and receives information to and from these units and outputs necessary commands are provided as main components. Yes.

  The acceleration sensor 3 is a sensor that detects accelerations in X, Y, and Z axes orthogonal to each other. For example, a Wheatstone bridge circuit is configured using a piezoresistive element, and a device that detects a change in resistance value may be used. it can. The acceleration signal detected by the acceleration sensor 3 is controlled via a filter (not shown) for extracting a predetermined frequency component, a signal conversion unit (not shown) for A / D converting and outputting the detection signal, and the like. Part 2 is taken in.

  The control unit 2 has functions for performing determination of the inclination of the meter based on the triaxial acceleration obtained by the acceleration sensor 3, opening / closing control of the shutoff valve 6 based on the determination result, alarm issuing control, and the like. The control unit 2 can be implemented by a microcomputer having a CPU, RAM, ROM, clock circuit, auxiliary memory unit, and the like as main components.

  Next, with reference to FIG. 3, the flow of inclination monitoring after the meter installation executed by the control unit 2 will be described. After the completion of meter installation (S101), a meter activation operation is performed (S102).

Next, the acceleration value is measured by the acceleration sensor, and the meter stationary state is confirmed by confirming that the three-axis value fluctuation is within a predetermined threshold (YES in S103).
In this state, initial offset values θ ₀ and φ ₀ are obtained (S104). Referring to FIG. 2, θ ₀ and φ ₀ are expressed by the above formulas (1) and (2) where Gx, Gy, and Gz are three-axis components of gravitational acceleration G. For the convenience of display, the direction of gravity is shown upward.

  When an earthquake occurs after the initial offset value is acquired, seismic intensity by the acceleration sensor or an index value (for example, SI value) corresponding to the seismic intensity is determined (S106). Although omitted in the present flow, in the case of actually corresponding to a predetermined seismic intensity or higher, the meter is shut off by the shut-off valve 6.

Furthermore, the meter is judged to be stationary after the earthquake. The stillness determination is performed based on whether or not the three-axis acceleration value fluctuation is equal to or less than a predetermined threshold (S107). If it is equal to or less than the threshold value (YES in S107), the post-earthquake offset values θe and φe are obtained by the above equations (1) and (2) (S108).

Further, the amount of change of the post-earthquake offset value with respect to the initial offset value is obtained (S109). Specifically, whether or not absolute values | θe−θ ₀ | and | φe−φ ₀ | of offset value differences are within predetermined threshold values (first threshold values in the claims) ε1 and ε2 or not. Determined. If it is equal to or less than the threshold (YES in S109), it is determined that the meter is not tilted due to the earthquake or can be ignored, and the meter is not shut off (to S106).

  If the absolute value of the difference between the offset values exceeds the threshold value (NO in S109), it is determined that the inclination of the piping due to the earthquake or the inclination of the entire ground is abnormal, and the meter is shut off by closing the shutoff valve. Is called. At the same time, alarm lighting is performed on the alarm display section 8. (S110).

  In this embodiment, an example in which the inclination is determined based on the three-axis components Gx, Gy, and Gz of the gravitational acceleration G has been shown. However, taking into account that the X component and the Y component are very small, the error also increases. It is good also as an aspect determined based only on. The same applies to the following embodiments.

  In the present embodiment, an example in which the inclinations θ and φ are obtained using inverse trigonometric functions has been described. However, a determination may be made based on the values of the trigonometric functions cos θ and tan φ of θ and φ.

  In the present embodiment, an example is shown in which different thresholds ε1 and ε2 are used for the offset variation absolute value after the initial and post-earthquake, but the same threshold may be used.

The judges, as the fluctuation amount evaluation index, an example of using the absolute value of the difference between the offset value before and after the earthquake, other metrics, for example, specific .theta.e / theta ₀ in both offset values, by .phi.e / phi ₀ etc. It is good also as an aspect.

<Second Embodiment>
Next, another embodiment of the present invention will be described. The present embodiment relates to an aspect in which the inclination when the meter is attached is not more than a predetermined threshold during the meter activation operation. Since the configuration of the present embodiment is the same as the configuration of the above-described embodiment, redundant description is omitted.
Referring to FIG. 4, S201 to S204 are the same as S101 to S104 of the first embodiment. ).

After obtaining the initial offset values θ ₀ and φ ₀ (S204), it is determined whether or not θ ₀ falls within a predetermined threshold value (second threshold value in the claims) α0 (S205). If the threshold value is exceeded (NO in S205), the meter mounting is reworked until the threshold value is reached (S201). If it is less than or equal to the threshold (YES in S205), the meter mounting is not reworked (S205).
Since the subsequent flow is the same as that of the first embodiment, a duplicate description is omitted.

<Third embodiment>
Furthermore, another embodiment of the present invention will be described. The present embodiment relates to an aspect in which the initial and post-earthquake offset fluctuations are not more than a predetermined threshold value as a condition for automatic meter return. The difference of the configuration of this embodiment from the above-described embodiments is that the control unit 2 further includes a meter automatic return availability determination function. Since other configurations are the same as the configurations of the first embodiment, redundant description is omitted.
Referring to FIG. 5, S301 to S306 are the same as S201 to S206 of the second embodiment.

  When an earthquake occurs after the meter starts operating, the acceleration sensor 3 determines the seismic intensity or an index value (for example, SI value) corresponding to the seismic intensity (S307). When it falls below a reference value (for example, a determination value corresponding to seismic intensity 5) (NO in S308), the flow from S208 of the second embodiment is executed.

If it is equal to or greater than the reference value (YES in S307), the shutoff valve 6 is closed to shut off the meter (S309).
After that, the meter is judged to be stationary after the earthquake ends. The stillness determination is performed based on whether or not the three-axis acceleration value fluctuation is equal to or less than a predetermined threshold (S310). If it is equal to or less than the threshold value (YES in S310), the post-earthquake offset values θe and φe are obtained by the above equations (1) and (2) (S311).

  Next, a fluctuation amount with respect to the initial offset value of the post-earthquake offset value is obtained (S312). Specifically, it is determined whether or not the absolute value of the difference between the offset values before and after the earthquake falls within predetermined threshold values (first threshold values in the claims) ε1 and ε2.

  If it is equal to or less than the threshold value (YES in S312), the presence / absence of pipe leakage is determined by detecting the minute flow rate by the flow sensor 4 and detecting the presence or absence of pressure drop by the pressure sensor 7 (S313). If these values satisfy a predetermined condition (YES in S313), if the meter is shut off in S309, an automatic return operation (open shut-off valve 6) is performed (S314), and the process returns to S307. .

  On the other hand, if these values are equal to or less than the reference value (NO in S313), the automatic return operation (opening of the shut-off valve 6) is not performed and the alarm display is lit (S315).

  The present invention can be widely applied not only to a gas meter but also to a measuring instrument having an upright state as an installation condition.

DESCRIPTION OF SYMBOLS 1 ... Gas meter 2 with acceleration sensor ... Control unit 3 ... Acceleration sensor 4 ... Flow rate sensor 5 ... Gas flow path 6 ... Shut-off valve 7 ... Pressure sensor 8 ... Alarm display 9 ... Usage amount display

Claims (3)

A gas meter equipped with a triaxial acceleration sensor and equipped with a function to block the meter based on seismic intensity judgment,
Means for obtaining an initial offset value (θ = θ ₀ , φ = φ ₀ ) in the three-axis directions based on an acceleration value measured by the acceleration sensor when the gas meter is installed;
Means for obtaining an offset value (θ = θe, φ = φe) after the end of the earthquake at the time of an earthquake in service of a gas meter;
Means for determining the amount of change from the initial offset value of the offset value after the end of the earthquake;
Means for shutting off the supply of the gas meter when the fluctuation amount exceeds the first threshold (ε1, ε2);
A gas meter equipped with an acceleration sensor.
However, the triaxial component of the gravitational acceleration G is Gx, Gy, Gz

The acceleration sensor-equipped gas meter according to claim 1, further comprising means for issuing an alarm when the initial offset value (θ = θ ₀ ) exceeds a second threshold value (α 0). When the safety of the piping system is confirmed after the end of the earthquake, it is further equipped with an automatic return function that automatically returns the shut-off meter, and
The acceleration sensor-equipped gas meter according to claim 1, further comprising means for not operating the automatic return function when the fluctuation amount exceeds the first threshold value.

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