JP2008111672A - Gas meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas meter improved in the safety of the gas shutoff function by detecting the gas flow or the pressure at an early stage. <P>SOLUTION: A gas flow detection means 15a instantaneously detects the gas flow when refilling the gas into a gas flow path 11 through a gas flowmeter 12 being the ultrasonic sensor. A determination means 15d determines whether the gas flow characteristics detected by the gas flow detection means 15a coincides with the gas flow characteristics previously stored in a memory means 15e or not. If the actually detected gas flow doesn't coincide with the previously stored flow characteristics, the determination means 15d determines generation of gas leak, and immediately shut off a shutoff valve 14 through a valve closing means 15c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas meter having a gas safety cutoff function corresponding to a gas flow rate and pressure.

  In recent years, in addition to a detection function for detecting a gas flow rate with a flow meter, a gas meter has a gas cutoff function for driving a gas cutoff valve to close a gas flow path when the detected gas flow rate is a predetermined value or more. Things are being developed. Therefore, safety is ensured by preventing gas leakage in the piping and accidents caused by this gas outflow.

  As a conventional technique, the flow rate of the gas flowing through the gas flow path is detected by the gas flow rate detection means, and the gas flow path is blocked by the valve opening / closing means in accordance with the detection result of the gas flow rate detection means, and the restoration work is performed. Subsequently, a gas meter has been proposed in which a gas is filled in a gas flow path by opening a valve, and then the valve opening / closing means again shuts off the gas flow path (see Patent Document 1).

In this gas meter, in the state where the gas flow path is shut off again, the detection result of the gas pressure detecting means is determined and the pressure change rate is obtained. It is determined whether it falls within the range, and it is further determined whether or not the pressure fluctuation value is within a predetermined reference value. Therefore, when the pressure fluctuation value is larger than the reference value, it is determined that there is a gas leak, and when it is within the reference value, it is determined that there is no gas leak. That is, when the pressure fluctuation value is determined to be within the reference value, the gas flow path is restored, and thereby the gas leak inspection is completed.
Japanese Patent No. 3359450

  By the way, in the prior art, the gas flow path is blocked by the valve opening / closing means according to the detection result of the gas flow rate detecting means, and after the restoration work is performed, the valve opening / closing means opens the valve by the return blocking means. Is refilled. Then, the valve opening / closing means is driven by the return shut-off means, and the gas flow path is shut off again. Under this condition, the gas pressure fluctuation is detected.

  Here, since the gas volume at the time of refilling is determined by the piping capacity of the gas piping downstream of the gas meter, the flow rate and time of the gas flowing through the meter can be determined from this gas volume. For this reason, since the refill time is set to the time determined from the maximum gas pipe capacity, the gas continues to be filled during the time determined from the maximum pipe capacity even with a short gas pipe capacity. In other words, if a pipe breakage or the like that causes a gas leakage occurs, the conventional gas meter that checks the pressure fluctuation after filling the gas leaks volume gas for the set time to the outside. The problem that cannot be guaranteed.

  In addition, during gas refilling, measurement must be performed as soon as possible. However, if measurement is performed with high accuracy in a short time, battery current consumption is large and the life of the product is shortened. Therefore, as in the prior art, the shutoff valve was closed after refilling was completed and the flow rate and pressure were measured over a long period of time. If this occurs, the volume of gas for the set time leaks to the outside, and safety is not guaranteed. In other words, when the gas is refilled, the gas is filled in the flow path in a short time, so it is necessary to provide a filling time as long as possible and measure the flow rate and pressure change of the system with a high system. It was.

  Further, in the prior art, there is no means for displaying the result during and after the restoration work of the pipe, and as a result, the shut-off valve opens or the restoration succeeds, or the shut-off valve does not open and the restoration is resumed. There was no means for the user to confirm only by failure. For this reason, the cause of the failure cannot be investigated unless the leakage confirmation after the return is completed, and the user's work efficiency has been significantly reduced.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to detect the gas flow rate and / or pressure at an early stage so that the safety of the gas shut-off function can be improved. The object is to provide an improved gas meter.

  In order to achieve the above-described object, the present invention provides a valve opening / closing means for controlling opening / closing of a shut-off valve installed in a gas flow path, and a pressure detection for detecting a pressure in the gas flow path provided downstream of the shut-off valve. Means for determining gas leakage, and when the pressure in the gas flow path is not detected by the pressure detection means, the valve opening / closing means opens the shut-off valve to fill the gas. Then, in the gas meter which closes the shut-off valve and determines the minute gas leakage from the pressure decrease by the determining means, the gas meter includes a gas flow rate detecting means for detecting the flow rate in the gas flow path, The flow rate in the gas flow path is detected when the gas is filled by opening the shut-off valve by the valve opening / closing means, and the determination means has a flow rate characteristic of the gas detected by the gas flow rate detection means. Predetermined And comparing the amount characteristic is determined that the gas leakage if they do not match, the valve opening and closing means may close the shut-off valve on the basis of the determination.

  The pressure detection means detects the pressure in the gas flow path when filling the gas by opening the shut-off valve by the valve opening / closing means, and the determination means is detected by the pressure detection means. When the gas pressure characteristic is compared with a predetermined pressure characteristic and the two do not match, it is determined that the gas leaks, and the valve opening / closing means closes the shut-off valve based on the determination. Is also an embodiment of the present invention.

  Furthermore, one aspect of the present invention includes a gas meter control method in which the above-described category of the invention is changed. The valve opening / closing means is characterized in that when the gas is filled by opening the shut-off valve, the flow rate of the inflowing gas is adjusted by limiting the open amount of the shut-off valve.

  In the above aspect, since the gas leakage can be detected by the change in the gas flow rate or pressure before the gas is completely filled in the flow path, the gas flow path can be immediately shut off, and as a result Since the amount of gas that leaks to the outside can be reduced, safety is improved.

  Further, since the opening amount of the shutoff valve can be adjusted, the flow rate of the gas flowing downstream is suppressed by the pressure loss with the shutoff valve, and the filling time can be prolonged. Therefore, it is possible to measure the flow rate and the pressure with high accuracy by the normal current consumption while the gas is being filled.

  According to the present invention as described above, since the gas can be shut off earlier than the set refilling time, it is possible to reduce the amount of gas leaked from the gas flow path to the outside, resulting in safety. A high gas meter can be provided. Further, by restricting the shutoff valve, the flow rate of the gas flowing downstream of the gas flow path is suppressed by the pressure loss with the shutoff valve, and the filling time can be prolonged. Furthermore, since the gas pressure data and the leakage factor can be displayed on the display unit, it is possible to promptly inform the user of the situation at the time of the failure of the gas flow path restoration. It is possible to improve and work on the return of the gas flow path more quickly.

1. This embodiment
[Constitution]
FIG. 1 shows a basic configuration of a gas meter according to an embodiment of the present invention. In order to avoid complication of illustration, in the following description, description of constituent parts for performing a measurement function similar to that of a general gas meter such as a calculation circuit system of an integrated gas flow value is omitted.

  This gas meter is provided with a gas flow path 11 as a pipe through which a gas supplied from the outside flows, and is configured to send gas to a consumer gas appliance (not shown) via the gas flow path 11. ing. The gas flow path 11 is provided with a shutoff valve 14 for shutting off the flow path in the event of an emergency such as gas leaking from the upstream side, and a gas flow rate measuring device 12 for measuring the gas flow rate on the downstream side thereof. A pressure measuring device 13 for measuring the gas pressure in the gas flow path is provided. In addition, the gas meter is provided with a control unit 15 that receives output signals from the gas flow rate measuring device 12 and the pressure measuring device 13 and determines whether or not there is a gas leak and controls the shut-off valve 14. Further, the gas meter is provided with a display unit 16 for displaying the pressure data and gas flow rate data of the gas in the gas flow path 11.

  The gas flow rate measuring instrument 12 measures the flow rate of the gas supplied from the upstream side to the downstream side of the gas flow path 11 in the same manner as that used in a general gas meter. For example, FIG. In this way, an ultrasonic sensor type is used. In addition, a guessing type such as a hot-wire method and a fluidic method, and a mechanical type such as a membrane type can be used. Of course, it is not limited to these types of measuring instruments, but an ultrasonic sensor type is preferable because it is necessary to instantaneously measure the gas flow rate. It is also necessary that the flow rate can be measured with sufficient accuracy.

  The pressure measuring device 13 measures the gas pressure in the gas flow path 11 flowing from the upstream side to the downstream side, similar to that used in a general gas meter. For example, as shown in FIG. Is using. As in the case of the gas flow rate measuring device 12, it is necessary that the pressure can be measured with sufficient accuracy.

  The shut-off valve 14 is a general valve that can electromagnetically perform both shut-off and return to close the valve body to shut off the flow of gas and open the valve body to allow gas to pass therethrough. The shut-off valve 14 is the same as the conventional one, and generally comprises a control valve that shuts off the gas flow in the gas flow path 11 and a drive unit that controls the control valve by a control signal from the control unit 15. . The shutoff valve 14 can freely adjust the control valve from the drive unit through the control unit 15 in order to obtain a predetermined flow rate. That is, the valve opening amount can be limited to adjust the flow rate of the flowing gas.

  The control unit 15 controls the opening / closing operation of the shut-off valve, and includes a CPU, a ROM, a RAM, a clock, and the like. Here, each means which the control part 15 has in order to open and close the shut-off valve will be described based on FIG.

  Reference numeral 15a denotes a gas flow rate detecting means for detecting the gas flow rate flowing through the gas flow path 11 through the gas flow rate measuring device 12. Reference numeral 15 b denotes a gas pressure detecting means for detecting a change in gas pressure in the gas flow path 11 through the pressure measuring device 13.

  15c is a valve opening / closing means for opening and closing the shutoff valve 14 installed in the gas flow path 11 in accordance with the detection result of the gas flow rate detection means 15a and the detection result of the gas pressure detection means 15b. Specifically, the valve opening / closing means 15c shuts off the gas flow path 11 according to the gas flow rate detected by the gas flow rate detection means 15a, and shuts off the gas flow path 11 after the gas flow is restored. It has a function of opening the valve 14 and closing the shut-off valve 14 again for investigating gas leakage in the gas flow path.

  15d compares a gas flow rate characteristic stored in advance in the storage unit 15e, which will be described later, with a gas flow rate characteristic actually detected by the gas flow rate detection unit 15a, and further includes a pressure characteristic stored in the storage unit 15e in advance. This is a determination means for comparing the pressure characteristic of the gas detected by the gas pressure detection means 15b to determine the gas leakage.

  Specifically, when the shut-off valve 14 is opened after the gas flow path 11 is restored and the gas is refilled, the gas flow rate characteristic flowing in the gas flow path 11 detected by the gas flow rate detection means 15a is stored in the storage means 15e in advance. If the stored gas flow rate characteristics do not match, it is determined that gas leakage occurs, and the valve opening / closing means 15c is controlled to close the shut-off valve 14. Further, even when the gas pressure characteristic detected by the gas pressure detection means 15b does not match the pressure characteristic stored in advance in the storage means 15e, it is determined that gas leakage occurs, and the shutoff valve 14 is connected to the valve opening / closing means 15c. Control the operation to close.

  On the other hand, in the case of detecting both the gas flow rate and the pressure when refilling the gas, the determination unit 15d stores the actually detected flow rate characteristic of the gas in the gas flow path 11 in the storage unit 15e. If it is determined that the gas flow characteristic matches the gas flow characteristic and that the actually detected gas pressure characteristic matches the pressure characteristic stored in the storage unit 15e, it is determined that there is no gas leakage. When refilling the gas, when detecting either the gas flow rate or pressure, if the detected data matches the characteristics stored in the storage means 15e, there is no gas leakage. It is determined to be a thing.

  Further, the determination means 15d also determines whether or not the gas pressure detected by the gas pressure detection means 15b is decreasing when the cutoff valve 14 is shut off.

  15e is a storage means for storing the flow rate characteristics and pressure characteristics of the gas in the predetermined gas flow path 11 as described above. Here, since the flow rate and time of the gas flowing through the gas meter are determined by the piping capacity of the gas flow path 11, the storage means 15e has the flow rate characteristics and pressure characteristics of the gas flowing in at the time of refilling corresponding to the size of the piping capacity. This is stored in advance.

  Note that the gas flow rate characteristic stored in advance in the storage means 15e refers to the inside of the gas flow path 11 when there is no gas leakage when the valve opening / closing means 15c is filled with gas by opening the shut-off valve 14. The flow rate value of the gas and the change with time of the flow rate. The gas pressure characteristics stored in advance in the storage means 15e relate to changes in the pressure value and pressure of the gas in the gas flow path 11 over time when there is no gas leakage when filling the gas. is there.

  Here, the storage means 15e stores a change in flow rate with time, which is a flow rate characteristic, that is, FIG. 9 in which the shutoff valve 14 is fully open and FIG. 13 in which the shutoff valve 14 is half open are stored. Further, FIG. 11 in which the shut-off valve 14 is fully opened and FIG. 15 in which the shut-off valve 14 is half-opened are stored as a change with time of the pressure characteristic, that is, a pressure fluctuation pattern. Each pattern is determined in advance depending on the pipe capacity of the gas flow path 11.

  The display unit 16 displays information related to gas including pressure data in the gas flow path 11 detected by the gas pressure detection means 15b. In addition to simply displaying the detected gas pressure data as a numerical value, it is also possible to display the figure of a character, a graph or the like in order to visually convey the fluctuation of the gas pressure data in an easily understandable manner.

  In addition, when the return of the gas flow path 11 fails due to gas leakage, the display unit 16 is provided with a mechanism for displaying a gas flow rate detection or a gas pressure drop detection as a cause of the failure. Further, in the embodiment described later, the display unit 16 stores a determination time which is a time required for the determination work by the gas flow rate or pressure determination means 15d, that is, a predetermined elapsed time for repeatedly performing the determination work. A mechanism for displaying in the form of quantity time is provided.

[Operation example]
Next, the operation example of the gas meter which is this invention is demonstrated with reference to the flowchart of FIGS. A display example of the display unit 16 will be described with reference to FIG. The flow characteristics used below indicate a flow pattern that is a change in gas flow over time, and the pressure characteristics indicate a pressure fluctuation pattern that is a change in gas pressure over time. is there.

(1) First Example In this example, gas leakage is detected according to the detection result of the gas flow rate detection means 15a, the gas flow path 11 is shut off through the valve opening / closing means 15c, and after the restoration work is completed. A confirmation flow of gas leakage in the gas flow path 11 will be described with reference to FIG. The following second to fourth embodiments also explain the flow of the gas leakage confirmation after recovery under this situation.

  After the restoration, first, in order to confirm the presence or absence of the gas pressure in the current gas flow path 11, whether or not there is a gas pressure through the pressure measuring device 13 by the gas pressure detection means 15b in the downstream portion of the gas flow path 11 is determined. Measure (STEP 301). When there is a gas pressure (NO), it is determined whether or not the detected gas pressure in the gas flow path 11 is lowered by the determination means 15d.

  On the other hand, when the gas pressure is not detected by the gas pressure detection means 15b (YES), the determination means 15d opens the shutoff valve 14 through the valve opening / closing means 15c (STEP 302). As a result, the gas passage 11 is again filled with gas.

  Here, as a feature of the present embodiment, the gas flow rate detecting means 15a instantaneously detects the flow rate of the gas flowing when refilling the gas flow path 11 through the gas flow rate measuring device 12 which is an ultrasonic sensor (STEP 303). ). Then, whether or not the gas flow rate characteristic detected by the gas flow rate detection unit 15a matches the gas flow rate characteristic stored in advance in the storage unit 15e is determined by the determination unit 15d (STEP 304).

  Specifically, as shown in FIG. 9, the storage unit 15 e has a flow rate characteristic of the inflowing gas at the time of gas refilling in the gas passage 11 without gas leakage, in accordance with the magnitude of the piping capacity of the gas passage 11. Accordingly, it is stored in advance. Here, the determination unit 15d uses the gas flow path 11 to determine the gas flow rate characteristic detected by the gas flow rate detection unit 15a when the gas is refilled as shown in FIG. 10 and the flow rate characteristic stored in the storage unit 15e. Corresponding to the capacity of.

  For example, when comparing the flow rate of the gas when the capacity of the pipe that is the gas flow path 11 is large, in FIG. 9 where there is no gas leakage, the gas flow rate suddenly increases when the gas flows in, but as the time passes, The gas is filled and the flow rate of the inflowing gas is lost. On the other hand, in the case where the leakage in FIG. 10 is large, the gas flow rate increases rapidly when the gas flows in, as in the case where there is no leakage, but the gas is not filled in the flow path 11 because the leakage is large. Even if time elapses, the gas flow rate, which is slightly smaller than that at the time of inflow, continues to flow into the flow path 11. That is, the determination means 15d determines the presence or absence of gas leakage based on the difference between the two. FIG. 10 shows an example of a flow rate pattern actually detected, not only when the capacity of the pipe that is the gas flow path 11 is large, but also when the capacity is small, and also corresponding to the magnitude of gas leakage. Yes.

  If it is determined by the determining means 15d that the actually detected flow rate characteristic of the gas does not match the previously stored flow rate characteristic (NO), a gas leak has occurred, so the valve opening / closing means 15c. Then, the shutoff valve 14 is immediately closed and the flow path 11 is shut off (STEP 305). On the other hand, when the determination unit 15d determines that the actually detected flow rate characteristic of the gas matches the previously stored flow rate characteristic (YES), the actual gas is used to confirm the gas leakage. The determination of about 5 seconds between the flow rate characteristic and the stored gas flow rate characteristic is repeated (STEP 306).

  When the determination time of about 5 seconds has elapsed (YES), the gas flow path 11 is blocked through the shutoff valve 14 by the valve opening / closing means 15c (STEP307). Thereafter, the pressure of the gas in the gas flow path 11 is detected by the gas pressure detection means 15b, and the determination means 15d determines whether or not the gas pressure in the pipe is lowered (STEP 308). If it is determined that the gas pressure has decreased (YES), the gas is leaking, and therefore the restoration work of the piping that is the gas flow path 11 has been unsuccessful (STEP 309).

  On the other hand, if the determination means 15d determines that the gas pressure has not decreased (NO), the gas pressure leakage confirmation determination operation for about 2 minutes is repeated (STEP 310). When the gas pressure leakage confirmation determination work for about 2 minutes is completed (YES), it is determined by the determination means 15d that there is no gas leakage, the valve opening / closing means 15c opens the shut-off valve 14, and the gas The return confirmation flow of the flow path 11 ends (STEP 311).

(2) Second Example In this example, as in the above example, the gas flow path 11 is blocked through the valve opening / closing means 15c, and the gas leakage in the gas flow path 11 is confirmed after the restoration operation is completed. The flow will be described with reference to FIG.

  After the restoration, first, similarly to the first embodiment, in order to confirm the presence or absence of the current gas pressure in the gas flow path 11, the gas pressure detection means 15 b passes through the pressure measuring device 13 in the downstream portion of the gas flow path 11. It is measured whether there is no gas pressure (STEP 401). When there is a gas pressure (NO), it is determined whether or not the detected gas pressure in the gas flow path 11 is lowered by the determination means 15d.

  On the other hand, if the gas pressure is not detected by the gas pressure detection means 15b (YES), the determination means 15d opens the shutoff valve 14 through the valve opening / closing means 15c (STEP 402). As a result, the gas passage 11 is again filled with gas.

  Here, as a feature of the present embodiment, the gas pressure detecting means 15b detects the gas pressure when refilling the gas flow path 11 through the pressure measuring device 13 (STEP403). Then, it is judged by the judging means 15d whether or not the pressure characteristic of the gas detected by the gas pressure detecting means 15b matches the pressure characteristic stored in advance in the storage means 15e (STEP 404).

  Specifically, as shown in FIG. 11, the storage unit 15 e has a pressure characteristic of the inflowing gas when the gas is refilled in the gas flow path 11 without gas leakage, and the magnitude of the pipe capacity of the gas flow path 11. Accordingly, it is stored in advance. Here, the determination means 15d uses the gas flow path 11 to determine the pressure characteristics of the gas detected by the gas pressure detection means 15b and the pressure characteristics stored in the storage means 15e as shown in FIG. Corresponding to the capacity of.

  For example, when comparing the pressure of the gas when the capacity of the pipe which is the gas flow path 11 is large, in FIG. 11 where there is no gas leakage, time passes from the time of gas inflow and the gas is filled in the flow path 11. The pressure increases as you go. On the other hand, when the gas leakage in FIG. 12 is large, the gas is not filled in the flow path 11 because a large amount of gas is leaking, and the rate of increase in pressure is small compared to the pressure characteristics without gas leakage. It will be a thing. That is, the determination means 15d determines the presence or absence of gas leakage based on the difference between the two. In addition, FIG. 12 shows not only a case where the capacity of the pipe that is the gas flow path 11 is large, but also a case where it is small as an example of the actually detected pressure pattern, and also corresponds to the magnitude of gas leakage. Yes.

  If it is determined by the determination means 15d that the actually detected pressure characteristic of the gas does not match the pressure characteristic stored in advance (NO), a gas leak has occurred, so the valve opening / closing means 15c. Then, the shutoff valve 14 is immediately closed to shut off the flow path 11 (STEP 405). On the other hand, when the determination unit 15d determines that the pressure characteristic of the actually detected gas matches the pressure characteristic stored in advance (YES), the actual gas is used to confirm the gas leakage. The determination of the pressure characteristic and the stored gas pressure characteristic is repeated for about 5 seconds (STEP 406).

  When the determination time of about 5 seconds elapses (YES), the gas flow path 11 is blocked through the shutoff valve 14 by the valve opening / closing means 15c (STEP407). Thereafter, the gas pressure in the gas flow path 11 is detected by the gas pressure detection means 15b, and the determination means 15d determines whether or not the gas pressure in the pipe is lowered (STEP 408). If it is determined that the gas pressure has decreased (YES), the gas is leaking, and therefore, the restoration work of the piping that is the gas flow path 11 has been unsuccessful (STEP 409).

  On the other hand, if the determination means 15d determines that the gas pressure has not decreased (NO), the gas pressure leakage confirmation determination operation for about 2 minutes is repeated (STEP 410). When the gas pressure leakage confirmation determination work for about 2 minutes is completed (YES), it is determined by the determination means 15d that there is no gas leakage, the valve opening / closing means 15c opens the shut-off valve 14, The return confirmation flow of the gas flow path 11 ends (STEP 411).

  As described above, according to the first and second embodiments, the gas can be shut off earlier than the set refill time, and as a result, the amount of gas leaking from the flow path 11 to the outside is reduced. Therefore, a highly safe gas meter can be provided.

(3) Third Example In this example, as in the above example, the gas flow path 11 is blocked through the valve opening / closing means 15c, and the gas leakage in the gas flow path 11 is confirmed after the restoration work is completed. The operation of extending the gas refill time in the flow will be described with reference to FIG.

  After the restoration, first, in order to confirm the presence or absence of the gas pressure in the current gas flow path 11, whether or not there is no gas pressure through the pressure measuring device 13 by the gas pressure detection means 15 b in the downstream portion of the gas flow path 11. Is measured (STEP 501). When there is a gas pressure (NO), it is determined whether or not the detected gas pressure in the gas flow path 11 is lowered by the determination means 15d.

  On the other hand, when no pressure is detected by the gas pressure detecting means 15b (YES), as a feature of the present embodiment, the determining means 15d causes the shut-off valve 14 to be half-opened through the valve opening / closing means 15c (STEP 502). Therefore, due to the pressure loss generated between the valve body of the shutoff valve 14 and the case, the flow rate of the gas flowing downstream is suppressed, and the time for refilling the gas in the gas flow path 11 is lengthened. The valve opening amount of the shut-off valve 14 is not limited to half-opening, and can be adjusted by the valve opening / closing means 15c in order to adjust the flow rate of the inflowing gas.

  Then, the gas flow rate detecting means 15a instantaneously detects the flow rate of the gas flowing when refilling the gas flow path 11 through the gas flow rate measuring device 12 which is an ultrasonic sensor (STEP 503). Then, whether or not the gas flow rate characteristic detected by the gas flow rate detection unit 15a matches the gas flow rate characteristic stored in the storage unit 15e in advance is determined by the determination unit 15d (STEP 504).

  Specifically, as shown in FIG. 13, the storage unit 15 e has a flow rate characteristic of the inflowing gas at the time of gas refilling in the gas flow path 11 without gas leakage, in accordance with the magnitude of the pipe capacity of the gas flow path 11. Accordingly, it is stored in advance. Here, as shown in FIG. 14, the determination unit 15d uses the gas flow rate characteristic detected by the gas flow rate detection unit 15a during gas refilling and the flow rate characteristic stored in the storage unit 15e as a gas flow. A comparison is made corresponding to the capacity of the path 11.

  For example, comparing the gas flow rate when the capacity of the pipe that is the gas flow path 11 is large, in FIG. 13 where there is no gas leakage, the gas flow rate suddenly increased when the gas flowed in, and the shut-off valve was half-opened. The flow rate is kept constant over time, and then the flow rate of the gas flowing in the flow path decreases. On the other hand, in the case where the leakage in FIG. 14 is large, the gas flow rate increases rapidly when the gas flows in, as in the case where there is no leakage, but the gas is filled in the flow path 11 because the leakage is large. No, the flow rate is kept constant over time. That is, the determination means 15d determines the presence or absence of gas leakage based on the difference between the two. FIG. 14 shows not only a case where the capacity of the pipe that is the gas flow path 11 is large but also a case where the capacity of the pipe that is the gas flow path 11 is small as an example of the actually detected flow rate pattern. ing.

  If it is determined by the determining means 15d that the actually detected flow rate characteristic of the gas does not match the previously stored flow rate characteristic (NO), a gas leak has occurred, so the valve opening / closing means 15c. Then, the shutoff valve 14 is immediately closed and the flow path 11 is shut off (STEP 505). On the other hand, when the determination unit 15d determines that the actually detected flow rate characteristic of the gas matches the previously stored flow rate characteristic (YES), the actual gas is used to confirm the gas leakage. The determination for about 5 seconds between the flow rate characteristic and the stored gas flow rate characteristic is repeated (STEP 506).

  When the determination time of about 5 seconds has elapsed (YES), the gas flow path 11 is blocked through the shut-off valve 14 by the valve opening / closing means 15c (STEP 507). Thereafter, the pressure of the gas in the gas flow path 11 is detected by the gas pressure detection means 15b, and the determination means 15d determines whether or not the pressure of the gas in the pipe has decreased (STEP 508). If it is determined that the gas pressure has decreased (YES), the gas is leaking, and therefore, the restoration work of the piping that is the gas flow path 11 has failed (STEP 509).

  On the other hand, if the determination means 15d determines that the gas pressure has not decreased (NO), the gas pressure leakage confirmation determination operation for about 2 minutes is repeated (STEP 510). Then, when the gas pressure leakage confirmation determination work for about 2 minutes is completed (YES), it is determined by the determination means 15d that there is no gas leakage, the valve opening / closing means 15c fully opens the shut-off valve 14, and the gas flow The return confirmation flow of the path 11 ends (STEP 511).

  In this embodiment, the valve opening / closing means 15c half-opens the shutoff valve 14 when refilling the gas into the gas flow path 11, but the gas filling time is longer than when the shutoff valve 14 is fully opened. It is not limited to half open as long as it can be made longer.

  As described above, in the third embodiment, the shutoff valve 14 is half-opened by the valve opening / closing means 15c, so the flow rate of the gas flowing downstream of the gas flow path 11 is suppressed by the pressure loss with the shutoff valve 14, and filling is performed. Longer time can be achieved.

  Specifically, as a change in the gas flow rate, a case where FIG. 9 in which the shutoff valve 14 is fully opened when there is no gas leakage is compared with FIG. 13 in which the shutoff valve 14 is half open will be described below. As shown in FIG. 9, the flow rate characteristic with the shut-off valve 14 fully opened increases rapidly when the gas flows in, and then the gas is immediately filled in the flow path 11, so that the flow rate immediately decreases in a short time. End up. On the other hand, in FIG. 13 in which the shutoff valve 14 is half-opened, the flow rate rapidly increases when the gas flows in, but thereafter the flow rate is kept constant for a certain period of time. That is, it is possible to ensure a longer gas filling time when the shutoff valve 14 is half open than when the shutoff valve 14 is fully opened. Since this is the same even when there is gas leakage, it can be remarkably confirmed that the valve opening amount of the shutoff valve 14 corresponds to the filling time.

(4) Fourth Example In this example, as in the above example, the gas flow path 11 is shut off through the valve opening / closing means 15c, and confirmation of gas leakage in the gas flow path 11 after completion of the restoration work is confirmed. The operation of extending the gas refill time in the flow will be described with reference to FIG.

  After the restoration, first, similarly to the above embodiment, in order to confirm the presence or absence of the current gas pressure in the gas flow path 11, the gas pressure is detected through the pressure measuring device 13 by the gas pressure detection means 15 b in the downstream portion of the gas flow path 11. Whether or not there is any is measured (STEP 601). When there is a gas pressure (NO), it is determined whether or not the detected gas pressure in the gas flow path 11 is lowered by the determination means 15d.

  On the other hand, when the pressure is not detected by the gas pressure detection means 15b (YES), as a feature of the present embodiment, the determination means 15d causes the shut-off valve 14 to be half-opened through the valve opening / closing means 15c (STEP 602). Thereby, due to the pressure loss generated between the valve body of the shutoff valve 14 and the case, the flow rate of the gas flowing downstream is suppressed, and the time for refilling the gas in the gas flow path 11 becomes longer. The valve opening amount of the shut-off valve 14 is not limited to half-opening, and can be adjusted by the valve opening / closing means 15c in order to adjust the flow rate of the inflowing gas.

  Then, the gas pressure detecting means 15b detects the gas pressure when refilling the gas flow path 11 through the pressure measuring device 13 (STEP 603). Thereafter, it is judged by the judging means 15d whether or not the pressure characteristics of the gas detected by the gas pressure detecting means 15b coincide with the pressure characteristics previously stored in the storage means 15e (STEP 604).

  Specifically, as shown in FIG. 15, in the storage unit 15 e, the pressure characteristic of the inflowing gas at the time of gas refilling in the gas flow path 11 without gas leakage is the magnitude of the pipe capacity of the gas flow path 11. Is stored in advance. Here, as shown in FIG. 16, the determination unit 15d uses the gas pressure characteristic detected by the gas pressure detection unit 15b during gas refilling and the pressure characteristic stored in the storage unit 15e as a gas flow. A comparison is made corresponding to the capacity of the path 11.

  For example, when comparing the pressure of the gas when the capacity of the pipe that is the gas flow path 11 is large, in FIG. 15 where there is no gas leakage, as time elapses from the time of gas inflow, the gas is filled in the flow path 11 and the pressure is increased. Will increase. On the other hand, when the gas leakage in FIG. 16 is large, a large amount of gas is leaking, so the gas is not filled in the flow path 11, and the rate of increase in pressure is small compared to the pressure characteristics without gas leakage. It will be a thing. That is, the determination means 15d determines the presence or absence of gas leakage based on the difference between the two. FIG. 16 shows an example of a pressure pattern that is actually detected, not only when the capacity of the pipe that is the gas flow path 11 is large, but also when the capacity is small, and also corresponding to the magnitude of gas leakage. Yes.

  If it is determined by the determination means 15d that the actually detected pressure characteristic of the gas does not match the previously stored pressure characteristic (NO), a gas leak has occurred. The shutoff valve 14 is immediately closed through the means 15c to shut off the flow path 11 (STEP 605). On the other hand, when the determination unit 15d determines that the pressure characteristic of the actually detected gas matches the pressure characteristic stored in advance (YES), the actual gas is used to confirm the gas leakage. The determination of the pressure and the stored gas pressure characteristic is repeated for about 5 seconds (STEP 606).

  When the determination time of about 5 seconds elapses (YES), the gas flow passage 11 is shut off through the shut-off valve 14 by the valve opening / closing means 15c (STEP 607). Thereafter, the pressure of the gas in the gas flow path 11 is detected by the gas pressure detection means 15b, and the determination means 15d determines whether or not the gas pressure in the pipe is lowered (STEP 608). If it is determined that the gas pressure has decreased (YES), the gas is leaking, and therefore, the restoration work of the piping that is the gas flow path 11 has failed (STEP 609).

  On the other hand, if the determination unit 15d determines that the gas pressure has not decreased (NO), the gas pressure leakage confirmation determination operation for about 2 minutes is repeated (STEP 610). When the gas pressure leakage confirmation determination work for about 2 minutes is completed (YES), it is determined by the determination means 15d that there is no gas leakage, the valve opening / closing means 15c opens the shut-off valve 14, The return confirmation flow of the gas flow path 11 ends (STEP 611).

  As described above, in the fourth embodiment, since the shutoff valve 14 is half-opened by the valve opening / closing means 15c, the flow rate of the gas flowing downstream of the gas flow path 11 is suppressed by the pressure loss with the shutoff valve 14, and filling is performed. Longer time can be achieved.

  Thus, when there is no gas leakage, comparing FIG. 11 in which the shut-off valve 14 is fully opened and FIG. 15 in which the shut-off valve 14 is half-opened, the rate of increase when the gas flows in when gas is refilled is It can be understood that the case where is fully open is more gradual than the case where it is fully open. That is, when the gas pressure detecting means 15b detects an increase to the peak value of the gas pressure, it is possible to ensure a longer detection time when the shutoff valve is half open.

(5) Display Example Next, a data display example based on the pressure value in the gas flow path 11 in the display unit 16 will be described with reference to FIG.

  FIG. 7A is a display example of pressure data detected by the gas pressure detection means 15b. In this case, the detected pressure data is displayed on the display unit 16 as a numerical value. That is, during the confirmation of the detected pressure data, the part displaying other information such as the gas flow rate is normally switched to the pressure value display.

  FIGS. 7B, 7 </ b> C, and 7 </ b> D are display examples of pressure data fluctuation in the gas flow path 11. FIG. 7b displays the case where the gas pressure data detected by the gas pressure detecting means 15b rises or falls on the display unit 16 as character data. 7C and 7D, on the other hand, it is easy to visually recognize the fluctuation of the pressure data by, for example, a graphic upward to the right when rising and downward to the right when falling. It is displayed in the form.

  FIG. 7E is a display example of the display unit 16 that displays, as character data, whether the cause of the failure in restoring the gas flow path 11 is the detection of the gas flow rate or the detection of the pressure drop. That is, in the above-described embodiment, when the actually detected gas flow rate or pressure characteristic does not match the characteristic stored in advance in the storage means 15e, and the recovery fails due to gas leakage, the leakage confirmation is performed. After that, character data for gas flow rate detection or pressure drop detection is displayed as the cause of failure for a certain period of time.

  FIG. 7 (f) shows a mode in which the determination time required for the determination work by the determination means 15d for the detected gas flow rate or pressure, that is, the predetermined elapsed time in which the determination work is repeated, is the remaining time in the embodiment described above. It is an example of a display of the display part 16 displayed by.

  According to the display example of the display unit 16 as described above, the user can grasp the pressure value in the gas flow path 11 and the failure factor in the leakage confirmation flow for returning the gas flow path 11, so the countermeasure work can be performed. Proposals can be made immediately, and work efficiency can be dramatically improved.

3. Other Embodiments The present invention is not limited to the above-described embodiments. When the gas is refilled, the gas flow rate detection means 15a of Example (1) detects and performs the flow rate of the gas. The following embodiment that includes both the pressure detection by the gas pressure detection means 15b of Example (2) is also included.

  In this embodiment, the gas flow path 11 is blocked through the valve opening / closing means 15c and the flow for confirming the leakage of the gas in the gas flow path 11 after the completion of the restoration work is described with reference to FIG. To do.

  As in the above embodiment, after the restoration, first, in order to confirm the presence or absence of the gas pressure in the current gas flow path 11, the gas pressure detection means 15 b passes through the pressure measuring device 13 in the downstream portion of the gas flow path 11. It is measured whether there is no gas pressure (STEP 801). When there is a pressure (NO), it is determined whether or not the detected gas pressure in the gas flow path 11 is lowered by the determination means 15d.

  On the other hand, when the gas pressure is not detected by the gas pressure detection means 15b (YES), the determination means 15d opens the shutoff valve 14 through the valve opening / closing means 15c (STEP 802). As a result, the gas passage 11 is again filled with gas.

  Here, as a feature of the present embodiment, the gas flow rate detecting means 15a instantaneously detects the flow rate of the gas flowing when the gas flow path 11 is refilled through the gas flow rate measuring device 12 which is an ultrasonic sensor (STEP 803). ). Further, in addition to the gas flow rate, the gas pressure is also detected by the gas pressure detecting means 15b through the pressure measuring device 13 (STEP 804).

  Then, the determination unit 15d determines whether or not the gas flow rate characteristic detected by the gas flow rate detection unit 15a matches the gas flow rate characteristic stored in the storage unit 15e in advance, and further the gas pressure detection unit 15b. It is determined whether or not the pressure characteristics of the gas detected by the above match the pressure characteristics stored in advance in the storage means 15e (STEP 805).

  If it is determined by the determining means 15d that at least one of the actually detected gas flow rate characteristic and gas pressure characteristic does not match the previously stored flow rate or pressure characteristic (NO), a gas leak occurs. Therefore, the shutoff valve 14 is immediately closed through the valve opening / closing means 15c to shut off the flow path 11 (STEP 806). On the other hand, if it is determined by the determination means 15d that both the actually detected gas flow rate characteristic and the gas pressure characteristic match the previously stored characteristic (YES), in order to confirm the gas leakage The determination of the actual gas flow rate and pressure and the stored characteristics is repeated for about 5 seconds (STEP 807).

  When the determination time of about 5 seconds has elapsed (YES), the gas flow path 11 is blocked through the shut-off valve 14 by the valve opening / closing means 15c (STEP 808). Thereafter, the gas pressure in the gas flow path 11 is detected by the gas pressure detection means 15b, and the determination means 15d determines whether or not the pressure of the gas in the pipe has decreased (STEP 809). If it is determined that the pressure has decreased (YES), the gas is leaking, and therefore, the restoration work of the piping that is the gas flow path 11 has failed (STEP 810).

  On the other hand, if the determination means 15d determines that the gas pressure has not decreased (NO), the gas pressure leakage confirmation determination operation for about 2 minutes is repeated (STEP 811). When the gas pressure leakage confirmation determination work for about 2 minutes is completed (YES), it is determined by the determination means 15d that there is no gas leakage, the valve opening / closing means 15c opens the shut-off valve 14, The return confirmation flow of the gas flow path 11 ends (STEP 812).

  The present invention also includes an embodiment in which the control method for half-opening the shutoff valve 14 described in the third and fourth embodiments is applied to another embodiment based on the flowchart of FIG. .

Configuration diagram of a gas meter in an embodiment of the present invention The block circuit diagram of the control part in the embodiment of the present invention Example 1 of the embodiment of the present invention Second example of embodiment of the present invention Example 3 of the embodiment of the present invention Fourth example of embodiment of the present invention Display example of the display unit in the embodiment of the present invention Examples in other embodiments of the present invention Flow characteristics (1) of the first example in the embodiment of the present invention Flow rate characteristics (2) of the first example in the embodiment of the present invention Pressure characteristics (2) of the second example in the embodiment of the present invention Pressure characteristics (2) of the second example in the embodiment of the present invention Flow characteristics (3) of the third example in the embodiment of the present invention Flow characteristic (2) of the third example in the embodiment of the present invention Pressure characteristics (4) of the fourth example in the embodiment of the present invention Pressure characteristics (2) of the fourth example in the embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Gas flow path 12 ... Gas flow rate measuring device 13 ... Pressure measuring device 14 ... Shut-off valve 15 ... Control part 15a ... Gas flow rate detection means 15b ... Gas pressure detection means 15c ... Valve opening / closing means 15d ... Determination means 15e ... Storage means 16 ... Display section

Claims (14)

Valve opening / closing means for controlling opening / closing of a shut-off valve installed in the gas flow path, pressure detecting means for detecting pressure in the gas flow path provided downstream of the shut-off valve, and determination means for determining gas leakage And when the pressure detection means does not detect the pressure in the gas flow path, the valve opening / closing means opens the shut-off valve to fill the gas, and then closes the shut-off valve, and the judgment means In the gas meter that judges the leakage of minute gas from the decrease in
Gas flow detection means for detecting the flow rate in the gas flow path,
This gas flow rate detecting means detects the flow rate in the gas flow path when filling the gas by opening the shut-off valve by the valve opening and closing means,
The determination means compares the gas flow rate characteristic detected by the gas flow rate detection means with a predetermined flow rate characteristic and determines that the gas leaks when both do not match,
The gas meter characterized in that the valve opening / closing means closes a shut-off valve based on the determination. Valve opening / closing means for controlling opening / closing of a shut-off valve installed in the gas flow path, pressure detecting means for detecting pressure in the gas flow path provided downstream of the shut-off valve, and determination means for determining gas leakage And when the pressure detection means does not detect the pressure in the gas flow path, the valve opening / closing means opens the shut-off valve to fill the gas, and then closes the shut-off valve, and the judgment means In the gas meter that judges the leakage of minute gas from the decrease in
The pressure detection means detects the pressure in the gas flow path when filling the gas by opening the shut-off valve by the valve opening and closing means;
The determination means compares the gas pressure characteristic detected by the pressure detection means with a predetermined pressure characteristic and determines that the gas leaks when both do not match,
The gas meter characterized in that the valve opening / closing means closes a shut-off valve based on the determination. Valve opening / closing means for controlling opening / closing of a shut-off valve installed in the gas flow path, pressure detecting means for detecting pressure in the gas flow path provided downstream of the shut-off valve, and determination means for determining gas leakage And when the pressure detection means does not detect the pressure in the gas flow path, the valve opening / closing means opens the shut-off valve to fill the gas, and then closes the shut-off valve, and the judgment means In the gas meter that judges the leakage of minute gas from the decrease in
Gas flow detection means for detecting the flow rate in the gas flow path,
The gas flow rate detecting means detects the flow rate in the gas flow path when filling the gas by opening the shut-off valve by the valve opening / closing means,
The pressure detection means detects the pressure in the gas flow path when filling the gas by opening the shut-off valve by the valve opening and closing means;
The determination unit compares the flow rate characteristic of the gas detected by the gas flow rate detection unit with a predetermined flow rate characteristic, and the pressure characteristic of the gas detected by the pressure detection unit and a predetermined pressure The characteristics are compared, and if at least one of the contrasts does not match, it is determined that there is a gas leak,
The gas meter characterized in that the valve opening / closing means closes a shut-off valve based on the determination.   The valve opening / closing means adjusts the flow rate of the inflowing gas by limiting the amount of opening of the shut-off valve when filling the gas by opening the shut-off valve. The gas meter according to any one of claims.   The predetermined gas flow rate characteristic is that the gas flow value and flow rate in the gas flow path when there is no gas leakage when the valve opening / closing means fills the gas by opening the shut-off valve. The gas meter according to any one of claims 1 to 3, wherein the gas meter changes with time.   The predetermined pressure characteristic of the gas is a pressure value of the gas in the gas flow path and a change with time of the gas when there is no gas leakage when filling the gas. The gas meter according to any one of 1 to 3.   Displays information on the gas including at least one of pressure data of the gas flowing in the gas flow path, change in the pressure data, gas leakage factor information, and determination time data which is a time required for determining the gas leakage. The gas meter according to claim 1, further comprising a display unit.   The said display part displays the said pressure data of the gas detected by the said pressure detection means, when filling gas by opening a shut-off valve by the said valve opening / closing means. Gas meter.   When the gas is filled by opening the shut-off valve by the valve opening / closing means, the display unit displays the change in the pressure data of the gas detected by the pressure detecting means as character or graphic information. The gas meter according to claim 7 or 8. When the determination unit compares the flow rate characteristic of the gas detected by the gas flow rate detection unit with a predetermined flow rate characteristic and determines that they do not match, or the pressure of the gas detected by the pressure detection unit When comparing the characteristics with a predetermined pressure characteristic and determining that they do not match,
The gas meter according to any one of claims 7 to 9, wherein the display unit displays the gas flow rate or pressure characteristic determined to be inconsistent by the determination unit as the leakage factor information of the gas.   The gas meter according to any one of claims 7 to 10, wherein the display unit displays a remaining amount of the determination time, which is a time required for determination of gas leakage by the determination unit. A valve opening / closing step for controlling opening / closing of a shut-off valve installed in the gas flow path, a pressure detecting step for detecting pressure in the gas flow path provided downstream of the shut-off valve, and a determination step for determining gas leakage And when the pressure in the gas flow path is not detected by the pressure detection step, the gas is filled by opening the shut-off valve by the valve opening / closing step, and then the shut-off valve is closed and the pressure is determined by the determination step. In the control method of the gas meter that judges the leakage of minute gas from the decrease in
A gas flow rate detecting step for detecting a flow rate in the gas flow path;
This gas flow rate detection step detects the flow rate in the gas flow path when filling the gas by opening the shutoff valve by the valve opening and closing step,
The determination step compares the flow rate characteristic of the gas detected by the gas flow rate detection step with a predetermined flow rate characteristic, and determines that there is a gas leak when both do not match,
The valve opening and closing step closes the shut-off valve based on the determination, and controls the gas meter. A valve opening / closing step for controlling opening / closing of a shut-off valve installed in the gas flow path, a pressure detecting step for detecting pressure in the gas flow path provided downstream of the shut-off valve, and a determination step for determining gas leakage And when the pressure in the gas flow path is not detected by the pressure detection step, the gas is filled by opening the shut-off valve by the valve opening / closing step, and then the shut-off valve is closed and the pressure is determined by the determination step. In the control method of the gas meter that judges the leakage of minute gas from the decrease in
The pressure detection step detects the pressure in the gas flow path when filling the gas by opening the shut-off valve in the valve opening / closing step,
In the determination step, the gas pressure characteristic detected in the pressure detection step is compared with a predetermined pressure characteristic, and when both do not match, it is determined that the gas leaks,
The valve opening and closing step closes the shut-off valve based on the determination, and controls the gas meter. A valve opening / closing step for controlling opening / closing of a shut-off valve installed in the gas flow path, a pressure detecting step for detecting pressure in the gas flow path provided downstream of the shut-off valve, and a determination step for determining gas leakage And when the pressure in the gas flow path is not detected by the pressure detection step, the gas is filled by opening the shut-off valve by the valve opening / closing step, and then the shut-off valve is closed and the pressure is determined by the determination step. In the control method of the gas meter that judges the leakage of minute gas from the decrease in
A gas flow rate detecting step for detecting a flow rate in the gas flow path;
The gas flow rate detection step detects the flow rate in the gas flow path when filling the gas by opening the shutoff valve by the valve opening / closing step,
The pressure detection step detects the pressure in the gas flow path when filling the gas by opening the shut-off valve in the valve opening / closing step,
The determination step compares the flow rate characteristic of the gas detected by the gas flow rate detection step with a predetermined flow rate characteristic, and the pressure characteristic of the gas detected by the pressure detection step and a predetermined pressure The characteristics are compared, and if at least one of the contrasts does not match, it is determined that there is a gas leak,
The valve opening and closing step closes the shut-off valve based on the determination, and controls the gas meter.

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