JP5618623B2 - Leakage detection system, leak detection device, and leak detection method - Google Patents

Description

  The present invention relates to a leak detection system, a leak detection device, and a leak detection method.

  Conventionally, there has been proposed a leak detection device that reliably detects a large amount of gas leakage caused by breakage of an embedded tube or a rubber tube. This leak detection device detects a gas pressure by a pressure sensor and determines whether or not the detected gas pressure is outside a normal range. And a leak detection apparatus judges that it is a mass leak, when the state which is outside a normal range continues more than predetermined time (for example, refer patent document 1).

JP 2002-31580 A

  However, in the conventional leak detection device, a large leak cannot be determined unless the gas pressure outside the normal range continues for a predetermined time or more. In particular, when the leak detection device is used in a gas supply system that supplies LP (Liquefied Petroleum) gas, the gas in the LP gas cylinder may almost flow out.

  The present invention has been made to solve such conventional problems, and an object of the present invention is to provide a leak detection system, a leak detection device, and a leak detection capable of detecting a large amount of leaks at an early stage. It is to provide a method.

The leak detection system of the present invention includes a main flow path for supplying fuel gas from a gas supply source to a plurality of houses, a bypass flow path for bypassing the main flow path, and a parent regulator provided in the main flow path And a sub-regulator that is provided in the bypass flow channel and has an adjustment pressure set higher than the adjustment pressure of the parent adjuster, and a leak detection device that detects a gas leak exceeding a predetermined flow rate. The leak detection device is a pressure value based on a signal output by pressure measuring means for storing a flow rate pressure characteristic in advance and outputting a signal corresponding to the pressure in the parent regulator in a predetermined time zone. a storage unit for storing as an initial value, and the pressure drop amount calculating means for calculating the pressure drop based on the output signal and the initial value by the pressure measuring means, by the pressure drop amount calculation means And a flow rate estimation means from the issued amount of pressure drop and the flow pressure characteristics that are stored in the storage unit estimates a flow rate, leakage detection means for detecting a predetermined flow rate or more gas leaks from the estimated flow rate by the flow rate estimating means And.

  According to this leak detection system, the pressure drop amount is calculated from a signal corresponding to the pressure in the parent regulator. Here, when the flow rate increases, the pressure of the parent regulator tends to decrease. Therefore, the flow rate can be estimated from the calculated pressure drop amount. In particular, since a pressure drop occurs relatively instantaneously as the flow rate increases, a large amount of leakage can be detected at an early stage.

  In the leak detection system of the present invention, it is preferable that the pressure drop amount calculating means calculates the pressure drop amount when a flow rate greater than a specified flow rate is generated.

  According to this leak detection system, the amount of pressure drop is calculated when the flow rate exceeds the specified flow rate. For example, when the flow rate hardly occurs and the pressure drop occurs due to changes in the ambient temperature. Therefore, the possibility of erroneously determining a large amount of leakage can be reduced.

  In the leak detection system of the present invention, it is preferable that the parent adjuster has an effect suppressing mechanism that suppresses a venturi effect.

  According to this leak detection system, since it has an effect suppressing mechanism that suppresses the venturi effect, the pressure changes according to the flow rate even in a high flow rate region, and the pressure drop amount even in an apartment house with a large number of houses. From this, the flow rate can be estimated.

In the leak detection device of the present invention, the flow pressure characteristic is stored in advance, and provided in a bypass flow path that bypasses a main flow path for supplying fuel gas from a gas supply source to a plurality of houses in a predetermined time zone. A storage unit that stores, as an initial value, a pressure value based on a signal output by a pressure measuring unit that outputs a signal corresponding to the pressure in the parent regulator set to a lower adjustment pressure than the child regulator, and the pressure Pressure drop amount calculating means for calculating the pressure drop amount based on the signal output from the measuring means and the initial value, the pressure drop amount calculated by the pressure drop amount calculating means, and the flow rate stored in the storage unit comprising: a flow rate estimation means for estimating a flow rate from the pressure characteristic, and a leak detection means for detecting a predetermined flow rate or more gas leaks from the estimated flow rate by the flow rate estimating means To.

  According to this leak detection device, the pressure drop amount is calculated from a signal corresponding to the pressure in the parent regulator. Here, when the flow rate increases, the pressure of the parent regulator tends to decrease. Therefore, the flow rate can be estimated from the calculated pressure drop amount. In particular, since a pressure drop occurs relatively instantaneously as the flow rate increases, a large amount of leakage can be detected at an early stage.

In the leak detection method of the present invention, a main flow path for supplying fuel gas from a gas supply source to a plurality of houses, a bypass flow path for bypassing the main flow path, and a parent provided in the main flow path An adjustment device, a child adjustment device provided in the bypass flow path, the adjustment pressure of which is set higher than the adjustment pressure of the parent adjustment device, and a leak detection device that detects a gas leak of a predetermined flow rate or more. A leak detection method for a leak detection system , wherein a storage step for storing a pressure value based on a signal output by a pressure measuring means for outputting a signal corresponding to a pressure in the parent regulator in a predetermined time zone as an initial value; , pre-serial and pressure drop amount calculation step of calculating the pressure drop based on the output signal and the initial value by the pressure measuring means, the pressure drop calculated in the pressure reduction quantity calculation process And having a flow rate estimation step of estimating the flow from the flow pressure characteristics being, and a leakage detection step of detecting a predetermined flow rate or more gas leaks from the estimated flow rate in the flow rate estimation process.

  According to this leakage detection method, the pressure drop amount is calculated from a signal corresponding to the pressure in the parent regulator. Here, when the flow rate increases, the pressure of the parent regulator tends to decrease. Therefore, the flow rate can be estimated from the calculated pressure drop amount. In particular, since a pressure drop occurs relatively instantaneously as the flow rate increases, a large amount of leakage can be detected at an early stage.

  According to the present invention, it is possible to provide a leakage detection system, a leakage detection device, and a leakage detection method that can detect a large amount of leakage at an early stage.

1 is a configuration diagram of a gas supply system including a leak detection system according to an embodiment of the present invention. It is a block diagram which shows the detail of the leak detection apparatus shown in FIG. It is a graph which shows an example of the flow volume-pressure characteristic of the parent regulator memorize | stored in the memory | storage part shown in FIG. It is a flowchart which shows the leak detection method which concerns on this embodiment, Comprising: The memory | storage process of an initial value is shown. It is a flowchart which shows the leak detection method which concerns on this embodiment, Comprising: The judgment process of mass leak is shown. It is a graph which shows an example of the flow volume-pressure characteristic of the parent regulator concerning a 2nd embodiment. It is a figure which shows the structure of the diaphragm upstream flow path of the parent regulator which concerns on 2nd Embodiment, Comprising: (a) shows sectional drawing, (b) has shown the front view.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a gas supply system 1 including a leak detection system according to an embodiment of the present invention. In the following, the gas supply system 1 that supplies LP gas as fuel gas will be described as an example. However, the present invention is not limited to this, and the gas supply system 1 may supply city gas.

  The gas supply system 1 is a housing facility that supplies fuel gas from a gas cylinder (gas supply source) 110 to a plurality of houses 2. The gas supply system 1 includes a leak detection system 100 and a house-side facility 200. The leak detection system 100 includes a gas cylinder 110, a gas flow path 120, pressure regulators 130 to 150, and a leak detection device 160.

  The gas channel 120 is a channel that continues from the gas cylinder 110 to the plurality of houses 2, and includes a main channel 121 and a bypass channel 122. The main channel 121 is a main channel that supplies fuel gas from the gas cylinder 110 to the plurality of houses 2. The bypass flow path 122 bypasses the main flow path 121, and both ends are connected to the main flow path 121.

  The pressure regulators 130 to 150 are provided on the gas flow path 120 and adjust the downstream gas pressure by two states, a closed state and an open state. Among these, the former regulator 130 is provided on the gas cylinder 110 side. The parent adjuster 140 is provided in the main channel 121. Specifically, the parent adjuster 140 is provided in a portion of the main channel 121 that is bypassed by the bypass channel 122. The child adjuster 150 is provided in the bypass flow path 122 and has an adjustment pressure set higher than the adjustment pressure of the parent adjuster 140. The leak detection device 160 is provided on the bypass flow path 122 in the gas flow path 120, and detects a gas leak exceeding a predetermined flow rate (that is, a large leak).

  The house-side facility 200 includes a plurality of individual gas passages 210, a plurality of valves 220, a plurality of gas meters 230, and a plurality of gas appliances 240. The plurality of individual gas passages 210 supplies the fuel gas flowing through the gas passage 120 to the plurality of houses 2. The plurality of individual gas passages 210 are branched from the gas passage 120 to supply fuel gas to the plurality of houses 2 respectively.

  The valve 220 is provided at an upstream portion of each individual gas flow path 210. By opening and closing the valve 220, a resident of each house 2 can draw fuel gas into the home.

  The gas meter 230 measures the flow rate of the fuel gas and displays the integrated flow rate. The plurality of gas appliances 240 are a gas stove, a fan heater, a water heater, a floor heating, a gas table, a gas BF bath, and the like.

  In such a gas supply system 1, the fuel gas with a small flow rate does not flow through the parent regulator 140 side due to a difference in adjustment pressure between the parent regulator 140 and the child regulator 150, and passes through the child regulator 150 side. It will flow. In addition, a large flow rate of fuel gas flows through both the parent regulator 140 and the child regulator 150.

  FIG. 2 is a configuration diagram illustrating details of the leakage detection device 160 illustrated in FIG. 1. As shown in FIG. 2, the leak detection device 160 includes a pressure sensor (pressure measurement means) 161, a flow rate sensor 162, a storage unit 163, and a control unit 164.

  The pressure sensor 161 outputs a signal corresponding to the pressure in the parent regulator 140, and is configured by a piezoresistive type or a capacitance type sensor. As shown in FIG. 1, the parent adjuster 140 has a tube 141 connected from the parent adjuster 140 to the leak detection device 160, and the pressure in the parent adjuster 140 is guided to the leak detection device 160. The pressure sensor 161 is installed so as to detect the pressure guided from the parent regulator 140, and outputs a signal corresponding to the pressure in the parent regulator 140.

  The flow sensor 162 outputs a measurement signal corresponding to the gas flow rate in the flow path of the leak detection device 160, and is constituted by an ultrasonic sensor, a flow sensor, or the like. The storage unit 163 stores various data, and stores a pressure initial value, which will be described later, and a flow rate-pressure characteristic of the parent regulator 140.

  The control unit 164 controls the entire leak detection device 160, and includes a pressure drop amount calculation unit (pressure drop amount calculation unit) 164a, a flow rate estimation unit (flow rate estimation unit) 164b, and a leak detection unit (leakage). Detecting means) 164c and a shutoff control unit 164d. The storage unit 163 and the control unit 164 can be configured by a CPU (Central Processing Unit).

  The pressure drop amount calculation unit 164a calculates the pressure drop amount from the signal output from the pressure sensor 161. For example, the pressure drop amount calculation unit 164a measures, as an initial value, a pressure in a time zone in which more gas is used during the day. Here, it is assumed that the initial value is 2.90 kPa. The pressure drop amount calculation unit 164a stores the initial value in the storage unit 163. Thereafter, the pressure drop amount calculation unit 164a measures the pressure and calculates the difference between the measured pressure and the initial value as the pressure drop amount.

  The flow rate estimating unit 164b estimates the flow rate from the pressure drop amount calculated by the pressure drop amount calculating unit 164a. The flow rate estimation unit 164b estimates the flow rate according to the flow rate-pressure characteristics of the parent regulator 140 stored in the storage unit 163.

  FIG. 3 is a graph showing an example of the flow rate-pressure characteristics of the parent regulator 140 stored in the storage unit 163 shown in FIG. As shown in FIG. 3, the parent regulator 140 has a pressure of 3.10 kPa when the flow rate is 0 L / h, and a pressure of 2.95 kPa when the flow rate is 400 L / h. Similarly, when the flow rate is 800 L / h, the pressure is 2.93 kPa, and when the flow rate is 1500 L / h, the pressure is 2.90 kPa.

  The flow rate estimation unit 164b estimates the flow rate based on the flow rate-pressure characteristics as shown in FIG. More specifically, first, it is stored as an initial value that the pressure is 2.95 kPa when the flow rate is 400 L / h. It is assumed that the pressure has decreased by 0.50 kPa. At this time, the flow rate estimation unit 164b estimates that the flow rate is 1500 L / h from the pressure drop amount.

  Reference is again made to FIG. The leak detection unit 164c detects a gas leak (that is, a large leak) that exceeds a predetermined flow rate from the flow rate estimated by the flow rate estimation unit 164b. Even if the gas appliances 240 are used all at once, a flow rate of 1500 L / h was estimated by, for example, the flow rate estimation unit 164b in a relatively small apartment house (2 units, 4 units, etc.) that does not generate a flow rate of 1500 L / h or more. If this is the case, it can be said that this is a mass leak. For this reason, the leakage detection unit 164c detects a large amount of leakage when the flow rate estimated by the flow rate estimation unit 164b is 1500 L / h.

  The predetermined flow rate for detecting a large amount of leakage can be set as appropriate depending on the size of the apartment house. Further, referring to FIG. 3, the pressures of 1500 L / h and 4000 L / h are the same value. For this reason, it is impossible to estimate a flow rate exceeding 1500 L / h. For example, when the flow rate is 400 L / h as an initial value, the pressure is stored as 2.95 kPa, and the pressure decreases by 0.50 kPa. Since it can be estimated that a flow rate of at least 1500 L / h is generated, there is no problem.

  In addition, the pressure varies with changes in ambient temperature. For this reason, it is desirable that the flow rate estimation unit 164b corrects the initial value according to the ambient temperature or corrects the estimated flow rate result.

  The shutoff control unit 165d is configured to close the shutoff valve when a large amount of leak is detected by the leak detection unit 164c. This shutoff control unit 165d may send a signal to close the valve directly to the shutoff valve, or send a fact of mass leakage to the gas management center or the like, and a signal to close the valve from the gas management center to the shutoff valve. May be sent.

  Further, it is desirable that the pressure drop amount calculation unit 164a calculates the pressure drop amount when a flow rate of a specified flow rate (for example, 21 L / h) or more is generated. This is because, for example, when there is almost no flow rate and a pressure drop occurs due to a change in ambient temperature, it is possible to reduce the possibility of erroneously determining a large leak.

  Next, the leak detection method according to the present embodiment will be described. FIG. 4 is a flowchart showing a leak detection method according to the present embodiment, and shows an initial value storing process. Note that the process shown in FIG. 4 may be initially performed only once, or may be performed at predetermined intervals such as every several days.

  First, as shown in FIG. 4, the control unit 162 determines whether or not a flow rate equal to or higher than the specified flow rate is generated based on a signal from the flow rate sensor 162 (S1). When it is determined that a flow rate exceeding the specified flow rate has not occurred (S1: NO), this process is repeated until it is determined that a flow rate greater than the specified flow rate has occurred.

  On the other hand, when it is determined that a flow rate equal to or higher than the specified flow rate has occurred (S1: YES), the control unit 164 determines whether or not it is a predetermined time zone (S2). Here, the predetermined time zone is a time zone in which the amount of gas used is higher than other time zones, such as in the morning or evening.

  If it is determined that it is not the predetermined time zone (S2: NO), the process proceeds to step S1. On the other hand, when it is determined that it is the predetermined time zone (S2: YES), the control unit 164 stores the flow rate value and the pressure value as initial values in the storage unit 163 (S3). Thereafter, the process shown in FIG. 4 ends.

  Note that the reason for storing the initial value when it is determined that it is the predetermined time zone (S2: YES) is as follows. First, the initial value is used for flow rate estimation by the flow rate estimation unit 164b. At this time, if the flow rate value and the pressure value when the gas usage amount is small are the initial values, there is a possibility that an error becomes large when the flow rate is estimated when a large flow rate is generated.

  As shown in FIG. 3, in the region where the flow rate is less than 200 L / h, the amount of pressure fluctuation is large according to the flow rate. For this reason, there is a high possibility that the measurement error also increases, and the error can be reduced by storing the flow rate value and pressure value in a predetermined time zone in which the gas usage is increased as the initial value. In particular, when the flow rate is less than 180 L / h, gas does not flow through the parent regulator 140, but gas flows only through the child regulator 150. For this reason, the flow rate-pressure characteristic is as shown by a broken line (see FIG. 3) when the child regulator 150 is taken into consideration. For this reason, if the flow rate value and the pressure value in this region are stored as initial values, an error is caused. Therefore, the error can be further reduced by storing the flow rate value and the pressure value in a predetermined time zone in which the amount of gas used is increased as the initial value.

  FIG. 5 is a flowchart showing the leak detection method according to the present embodiment, and shows a process for determining a large leak. Note that the processing illustrated in FIG. 5 is repeatedly executed until the power of the leakage detection device 160 is turned off.

  First, as shown in FIG. 5, the control unit 162 determines whether or not a flow rate equal to or higher than the specified flow rate is generated based on a signal from the flow rate sensor 162 (S11). When it is determined that a flow rate exceeding the specified flow rate has not occurred (S11: NO), this process is repeated until it is determined that a flow rate greater than the specified flow rate has occurred.

  On the other hand, when it is determined that a flow rate equal to or higher than the specified flow rate has occurred (S1: YES), the control unit 164 measures the pressure in the parent regulator 140 based on the signal from the pressure sensor 161 (S12). Next, the pressure drop amount calculation unit 164a calculates the pressure drop amount from the pressure measured in step S12 and the initial value (pressure value) stored in step S3 of FIG. 4 (S13).

  Next, the flow rate estimation unit 164b estimates the flow rate from the pressure drop amount calculated in step S13, the initial value (flow rate value), and the data table stored in the storage unit 163 (S14). Then, the leakage detection unit 164c determines whether or not the flow rate calculated in step S14 is equal to or greater than a predetermined flow rate (S15).

  When it is determined that the flow rate calculated in step S14 is not equal to or higher than the predetermined flow rate (S15: NO), the process illustrated in FIG. 5 ends. On the other hand, when it is determined that the flow rate calculated in step S14 is equal to or greater than the predetermined flow rate (S15: YES), the cutoff control unit 164d executes control for closing the cutoff valve (S16). Thereafter, the process shown in FIG. 5 ends.

  Thus, according to the leak detection system 1, the leak detection device 160, and the leak detection method according to the present embodiment, the pressure drop amount is calculated from the signal corresponding to the pressure in the parent adjuster 140. Here, when the flow rate increases, the pressure of the parent regulator 140 tends to decrease. Therefore, the flow rate can be estimated from the calculated pressure drop amount. In particular, since a pressure drop occurs relatively instantaneously as the flow rate increases, a large amount of leakage can be detected at an early stage.

  In addition, in order to calculate the amount of pressure drop when a flow rate exceeding the specified flow rate is generated, for example, when there is almost no flow rate and a pressure drop occurs due to a change in ambient temperature, a large amount of leakage is mistakenly detected. The possibility of making a determination can be reduced.

  Next, a second embodiment of the present invention will be described. The leak detection system 1 according to the second embodiment is the same as that of the first embodiment, but the configuration and processing contents are partially different. Hereinafter, differences from the first embodiment will be described.

  First, in the parent adjuster 140 according to the second embodiment, the venturi effect is suppressed. That is, the normal parent regulator 140 has a structure for exhibiting the venturi effect, so that the pressure does not decrease as the flow rate increases as in the region where the flow rate is 1500 L / h or more shown in FIG. It has become.

  On the other hand, since the Venturi effect is suppressed in the parent adjuster 140 according to the second embodiment, as shown in FIG. 6, even in a region where the flow rate is 1500 L / h or more, the flow rate increases. The pressure drops.

  FIG. 6 is a graph illustrating an example of a flow rate-pressure characteristic of the parent regulator 140 according to the second embodiment. As shown in FIG. 6, when the venturi effect is suppressed, the parent regulator 140 has a pressure of 2.90 kPa when the flow rate is 1500 L / h and a pressure of 2.90 kPa when the flow rate is 4000 L / h. 85 kPa.

  In the second embodiment, the storage unit 163 stores a flow rate-pressure characteristic as shown in FIG. Therefore, the flow rate estimation unit 164b according to the second embodiment can estimate the flow rate in the region of 1500 L / h or more based on the pressure drop amount calculated by the pressure drop amount calculation unit 164a.

  In addition, by suppressing the venturi effect, the flow rate-pressure characteristic is substantially linear from a flow rate of 200 L / h to 4000 L / h. Therefore, the storage unit 163 may store an approximate expression obtained by linearly approximating a flow rate-pressure characteristic from a flow rate of 200 L / h to 4000 L / h.

  Here, there are a plurality of effect suppression mechanisms for suppressing the venturi effect of the parent adjuster 140, but the following effect suppression mechanisms are preferably employed. 7A and 7B are diagrams showing the structure of the diaphragm upstream flow path of the parent adjuster 140 according to the second embodiment, wherein FIG. 7A shows a cross-sectional view and FIG. 7B shows a front view.

  As shown in FIG. 7A, a valve 141 having a substantially H cross section is provided in a flow path upstream of a diaphragm (not shown). A rubber member 142 is attached to the upstream side of the valve 141.

  Further, as shown in FIGS. 7A and 7B, the valve 141 has a protrusion 141a that closes the upper part of the downstream flow path. In the present embodiment, a diaphragm is provided on the upper side of the flow path. By closing the upper side of the flow path, gas flows from below the flow rate, and this gas pushes up the diaphragm located above. Thereby, the venturi effect is canceled and suppressed.

  As described above, since the venturi effect is suppressed, a flow rate of 1500 L / h or more can be estimated, and a large amount of leakage can be detected at an early stage in a relatively large apartment house (such as 5 or more).

  In this way, according to the leak detection system 1, the leak detection device 160, and the leak detection method according to the second embodiment, it is possible to detect a large amount of leaks at an early stage and to erroneously determine a large amount of leaks. Can be reduced.

  In addition, since it has an effect suppression mechanism that suppresses the Venturi effect, the pressure changes according to the flow rate even in a high flow rate region, and the flow rate is estimated from the pressure drop amount even in an apartment house with many units. Can do.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention.

  For example, in the present embodiment, the leak detection device 160 includes the pressure sensor 161. However, the present invention is not limited thereto, and the parent adjuster 140 includes a pressure sensor, and a signal from the pressure sensor is input to the leak detection device 160. It may be.

DESCRIPTION OF SYMBOLS 1 ... Gas supply system 2 ... House 100 ... Leak detection system 110 ... Gas cylinder (gas supply source)
DESCRIPTION OF SYMBOLS 120 ... Gas flow path 121 ... Main flow path 122 ... Bypass flow path 130 ... Original regulator 140 ... Parent regulator 141 ... Valve 141a ... Projection part 142 ... Rubber member 150 ... Child regulator 160 ... Leak detector 161 ... Pressure sensor (Pressure measuring means)
162 ... Flow sensor 163 ... Storage unit 164 ... Control unit 164a ... Pressure drop amount calculation unit (pressure drop amount calculation means)
164b ... Flow rate estimating unit (flow rate estimating means)
164c ... Leakage detection unit (leakage detection means)
164d ... Blocking control unit 200 ... Housing-side equipment 210 ... Multiple individual gas flow paths 220 ... Multiple valves 230 ... Multiple gas meters 240 ... Multiple gas appliances

Claims (4)

A main flow path for supplying fuel gas from a gas supply source to a plurality of houses,
A bypass channel bypassing the main channel;
A parent adjuster provided in the main flow path;
A child adjuster provided in the bypass flow path, the adjustment pressure of which is set higher than the adjustment pressure of the parent adjuster;
A leak detection system comprising a leak detection device that detects a gas leak exceeding a predetermined flow rate,
The leak detection device stores a flow rate pressure characteristic in advance, and stores, as an initial value, a pressure value based on a signal output by a pressure measuring unit that outputs a signal corresponding to the pressure in the parent regulator in a predetermined time zone. wherein a storage unit, and the pressure drop amount calculating means for calculating the pressure drop based on the output signal and the initial value by the pressure measuring means, the pressure drop calculated by the pressure drop amount calculating means for A flow rate estimating means for estimating a flow rate from the flow rate pressure characteristics stored in the storage unit, a leak detecting means for detecting a gas leak of a predetermined flow rate or higher from the flow rate estimated by the flow rate estimating means,
A leak detection system comprising: The leakage detection system according to claim 1, wherein the pressure drop amount calculation unit calculates the pressure drop amount when a flow rate equal to or higher than a specified flow rate is generated. The flow pressure characteristics are stored in advance, and the adjustment pressure is higher than that of the child regulator provided in the bypass flow path that bypasses the main flow path for supplying fuel gas from the gas supply source to the plurality of houses in a predetermined time zone. A storage unit that stores, as an initial value, a pressure value based on a signal output by a pressure measuring unit that outputs a signal corresponding to a pressure in a parent regulator set to be low ;
A pressure drop amount calculating means for calculating a pressure drop amount based on the signal output by the pressure measuring means and the initial value ;
A flow rate estimating means for estimating a flow rate from a pressure drop amount calculated by the pressure drop amount calculating means and a flow rate pressure characteristic stored in the storage unit ;
A leak detection means for detecting a gas leak of a predetermined flow rate or higher from the flow rate estimated by the flow rate estimation means;
A leak detection device comprising: A main flow path for supplying fuel gas from a gas supply source to a plurality of houses,
A bypass channel bypassing the main channel;
A parent adjuster provided in the main flow path;
A child adjuster provided in the bypass flow path, the adjustment pressure of which is set higher than the adjustment pressure of the parent adjuster;
A leak detection method of a leak detection system comprising a leak detection device that detects a gas leak of a predetermined flow rate or more,
A storage step of storing, as an initial value, a pressure value based on a signal output by a pressure measuring unit that outputs a signal corresponding to the pressure in the parent regulator in a predetermined time zone;
A pressure drop amount calculating step for calculating a pressure drop amount based on the signal output by the pressure measuring means and the initial value ;
A flow rate estimating step for estimating a flow rate from the pressure drop amount calculated in the pressure drop amount calculating step and a flow rate pressure characteristic stored in advance ;
A leak detection step of detecting a gas leak of a predetermined flow rate or higher from the flow rate estimated in the flow rate estimation step;
A leakage detection method characterized by comprising:

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