JP2012207818A - Gas leakage prevention device and gas leakage prevention method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent gas leakage over a comparatively long period while accurately detecting presence of gas leakage from a connection of a gas pipe.SOLUTION: The gas leakage prevention device includes a first chamber forming body 15 for air-tightly and externally surrounding the connection 12 of the gas pipe 11 in which gas G flows to form a first chamber R1, and further includes a second chamber forming body 16 for forming a second chamber R2 separated from the first chamber R1 and capable of storing gas G. The first chamber forming body 15 is provided with a communication means 17 for making the first chamber R1 communicate with the second chamber R2 if the internal pressure in the first chamber R1 becomes setting pressure or more.

Description

  The present invention relates to a gas leakage prevention device provided with a first chamber forming body that hermetically surrounds a connecting portion of a gas pipe through which a gas flows and forms a first chamber, and a gas using the gas leakage prevention device The present invention relates to a leakage prevention method.

Conventionally, as a device for detecting leakage of gas at a connecting portion (for example, a flange connecting portion) of a gas pipe and preventing leakage gas from being diffused into the atmosphere, a cover portion that hermetically surrounds the connecting portion is provided. An apparatus including a gas detector that detects the presence or absence of gas in the internal space of the cover portion is known (see Patent Document 1).
In this apparatus, the presence or absence of gas leakage at the connection portion is detected by detecting the gas leaked from the connection portion into the internal space of the cover portion with a gas detector. At this time, since the cover part hermetically surrounds the connection part, leakage gas can be prevented from being diffused into the atmosphere.

Japanese Utility Model Publication No.51-955

  In the above-described apparatus, in particular, when detecting a small amount of leaking gas, it is desirable to reduce the capacity of the internal space formed by the cover part from the viewpoint of accurately detecting the gas with the gas detector. However, if the capacity of the internal space of the cover portion is reduced in this way, the amount of leaked gas that can be stored in the internal space of the cover portion is reduced, the time for storing the leaked gas is limited, and the internal pressure of the cover portion is limited. As a result, the cover portion may not be able to prevent leakage in a relatively short time. For this reason, the operator has had to take measures for the connection portion within a relatively short time after detecting gas leakage.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to detect the presence or absence of gas leakage from the connecting portion of the gas pipe with high accuracy, while leaking gas over a relatively long time. The object of the present invention is to provide a gas leakage prevention device and a gas leakage prevention method that can prevent the gas from being released into the atmosphere.

In order to achieve the above object, the gas leakage prevention device of the present invention comprises:
A gas leakage prevention device comprising a first chamber forming body that hermetically surrounds a connecting portion of a gas pipe through which gas flows, and forms a first chamber,
A second chamber forming body for forming a second chamber capable of storing gas separately from the first chamber;
The first chamber forming body is provided with communication means for communicating the first chamber and the second chamber when the internal pressure of the first chamber becomes a set pressure or higher.

According to the above characteristic configuration, since the first chamber formed by the first chamber forming body and the second chamber formed by the second chamber forming body are separately provided, each has a desired volume. be able to.
Thus, first, the first chamber formed by the first chamber forming body is set to have a relatively small volume, so that the presence or absence of gas leaking from the connection portion can be accurately detected.
In addition, if the operator cannot immediately take measures against the gas leakage for some reason after detecting the gas leakage with a relatively small capacity of the first chamber and confirming the gas leakage, it is as long as possible. Although it is preferable that leakage gas can be prevented from being released into the atmosphere over time, in the present invention, a second chamber is provided separately from the first chamber, and the internal pressure of the first chamber becomes equal to or higher than the set pressure. Communication means for communicating between the first chamber and the second chamber is provided.
As a result, when the gas leakage from the connecting portion to the first chamber continues and the internal pressure of the first chamber becomes equal to or higher than the set pressure, the communication means works to connect the first chamber and the second chamber. Therefore, gas can be guided from the first chamber having a relatively small volume to the second chamber, and the gas can be stored in the second chamber. In this case, the storage time in the second chamber can be extended by setting the second chamber to a relatively large volume. That is, by providing the first chamber and the second chamber as the leakage gas storage portion, it is possible to secure a sufficient time for starting the repair of the connection portion.
As described above, in the first chamber, it is confirmed that gas leakage has occurred, and in the first chamber and the second chamber, leakage gas is stored to check whether there is gas leakage from the connecting portion of the gas pipe. The gas leakage prevention device that can prevent leakage gas from being released to the atmosphere over a relatively long time while detecting the gas accurately.

A further characteristic configuration of the gas leakage preventing device of the present invention is as follows.
The said 2nd chamber formation body exists in the point comprised with the material whose pressure | voltage resistance is lower than the said 1st chamber formation body.

  As described above, the second chamber formed by the second chamber forming body is provided separately from the first chamber that should have a relatively small volume. The leakage gas pressure in the state of flowing into the chamber is low. From this point, the second chamber forming body forming the second chamber may be made of a material having a low pressure resistance, for example, a material having a lower pressure resistance than the first chamber forming body forming the first chamber. Can be configured. Therefore, for example, a highly flexible and small occupied space can be adopted as the second chamber forming body.

A further characteristic configuration of the gas leakage preventing device of the present invention is as follows.
Comprising gas concentration measuring means for measuring the gas concentration in the first chamber;
There is an inspection interval deriving unit for deriving an inspection interval of the gas leakage state of the connecting portion by the operator based on a change in the gas concentration measured by the gas concentration measuring unit.

According to the above characteristic configuration, the gas concentration measuring means measures the gas concentration in the first chamber. The inspection interval deriving unit derives the inspection interval based on the change in gas concentration, in other words, the rate of change in gas concentration over a predetermined time.
Specifically, the inspection interval deriving means estimates the set time when the first chamber and the second chamber are equal to or higher than the set pressure based on the gas concentration change rate during a predetermined time, and estimates a safety factor for the set time. To derive the inspection interval.
Thereby, if an operator checks a connection part based on the said inspection space | interval, possibility that leaked gas will be discharge | released to air | atmosphere can be reduced. As a result, the worker can ensure the safety of the site without having to reside at the site of the gas leak.

A further characteristic configuration of the gas leakage preventing device of the present invention is as follows.
There is a communication means for urging the operator to check at the check timing based on the check interval derived by the check interval deriving means.

  According to the above characteristic configuration, the communication unit can prompt the worker to perform an inspection at an appropriate inspection timing based on the appropriate inspection interval derived by the inspection interval deriving unit. As a result, the operator can inspect the site of gas leakage at an appropriate inspection timing, and can ensure the safety at the site more appropriately.

A further characteristic configuration of the gas leakage preventing device of the present invention is as follows.
Pressure monitoring means for measuring the pressure in the second chamber;
There is an inspection promoting means for urging the operator to check the gas leakage state of the connecting portion when the pressure monitored by the pressure monitoring means exceeds a pressure threshold value.

  According to the above characteristic configuration, when the pressure in the second chamber monitored by the pressure monitoring unit exceeds the pressure threshold value, the inspection promoting unit prompts the operator to check the gas leakage state of the connection portion. When the pressure in the two chambers exceeds the pressure threshold and the risk of gas leakage increases, the operator can be quickly sent to check the connection.

A further characteristic configuration of the gas leakage preventing device of the present invention is as follows.
The first chamber forming body includes a partition wall that hermetically surrounds the connection portion,
The communication means includes a relief valve that opens and closes a communication hole formed in the partition, or a rupture disk provided as a part of the partition.

  According to the above characteristic configuration, the communication means can be realized by a relatively simple configuration in which the relief valve or the rupture disk that can be set with the opening pressure as the set pressure is provided in the partition wall.

The characteristic configuration of the gas leakage prevention method using the gas leakage prevention apparatus including the first chamber and the second chamber described above is as follows:
Measuring the gas concentration in the first chamber;
Based on the measured change in the gas concentration, an inspection interval of the connecting portion by an operator is derived.

  According to the above characteristic configuration, since the inspection interval is derived based on the change in the gas concentration in the first chamber, in other words, the rate of change in the gas concentration in the first chamber for a predetermined time, substantial gas leakage at the connection portion The inspection interval can be derived based on the quantity. As a result, the inspection interval can more appropriately reflect the situation at the site.

Further features of the gas leakage prevention method of the present invention are as follows:
The point is to prompt the operator to inspect the connecting portion at the inspection timing based on the inspection interval.

  According to the above characteristic configuration, the operator is encouraged to check the site for gas leakage at an appropriate inspection timing derived based on an appropriate inspection interval. The site can be inspected at an appropriate inspection timing.

It is a schematic block diagram of the gas leak prevention apparatus which concerns on 1st Embodiment. It is a flowchart which shows the function of the gas leak prevention apparatus which concerns on 1st Embodiment. It is a schematic block diagram of the gas leak prevention apparatus which concerns on 2nd Embodiment. It is a flowchart which shows the function of the gas leak prevention apparatus which concerns on 2nd Embodiment. It is a graph which shows the change of the internal pressure of the 1st chamber of the gas leak prevention apparatus of this invention, and a 2nd chamber.

The gas leakage prevention device of the present invention can accurately detect the presence or absence of the leakage of the gas G in the gas pipe 11 and, when the leakage of the gas G occurs, the leakage gas G over a relatively long time. Can be prevented from being released into the atmosphere, and in particular, even when there is no worker at the site where the gas G leaks, safety at the site can be ensured.
Hereinafter, specific embodiments of the present invention will be described by describing the first and second embodiments of the present invention with reference to the drawings.

[First Embodiment]
The gas leakage prevention device of the present invention is applied to, for example, a connection part 12 (specifically, a flange connection part) of a gas pipe 11 as an intermediate pressure pipe (gas pressure: 0.10 MPa to 0.99 MPa). . In the connecting portion 12, as shown in FIG. 1, a gasket (not shown) is interposed between the flange joint 13a of the gas pipe 11a on one side and the flange joint 13b of the gas pipe 11b on the other side. Therefore, it is connected by being fastened by the fastener 14.

The gas leakage prevention device of the present invention allows the gas G to flow in order to appropriately detect the leakage of the gas G at the connection portion 12 and to store the leaked gas G for a relatively long time. A plate-shaped blocking member 15 (an example of a first chamber forming body) that hermetically surrounds the connection portion 12 of the gas pipe 11 to form the first chamber R1 is provided, and the gas G is stored separately from the first chamber R1. A cloth-like blocking member 16 (an example of a second chamber forming body) that forms a possible second chamber R2 is provided, and the plate-like blocking member 15 has a communication pressure P (the internal pressure of the first chamber R1 is a set pressure). A rupture disk 17 (an example of a communication means) is provided for communicating the first chamber R1 and the second chamber R2 when the value is equal to or greater than 0.10 MPa and 0.30 MPa.
Hereinafter, the configuration in which the first chamber R1 is formed by the plate-shaped blocking member 15, the configuration in which the second chamber R2 is formed by the cloth-shaped blocking member 16, and the point that the rupture disk 17 functions as the communication means will be described. These will be described in order.

  The plate-like blocking member 15 is an annular shape that covers the outside of the connecting portion 12 in an airtight manner and stores the gas G leaked from the connecting portion 12 in close contact with the outer surface of the gas pipe 11 in the vicinity of the connecting portion 12. A partition wall 23 is used.

The cloth-like blocking member 16 is provided in a state of airtightly surrounding the outside of the plate-like blocking member 15, and both ends thereof are fastened to the outer periphery of the gas pipe 11 by a steel belt 27 or the like. The cloth-like blocking member 16 is made of a material having no air permeability so as to form the second chamber R2 for storing the gas G therein. The second chamber R2 is formed for the purpose of temporarily storing the gas G when the internal pressure of the first chamber R1, which will be described later, becomes equal to or higher than the communication pressure P.
The cloth-shaped blocking member 16 can be made of a material having a lower pressure resistance than the plate-shaped blocking member 15 that forms the first chamber R1. For this reason, the cloth-like blocking member 16 can employ a highly flexible material that is simple in configuration and easy to carry. As a specific material, a vinyl chloride sheet reinforced with nylon cloth or the like can be employed.

A part of the partition wall 23 includes a rupture disk 17 (an example of communication means) that communicates the first chamber R1 and the second chamber R2 when the internal pressure of the first chamber R1 becomes equal to or higher than the communication pressure P. Is provided.
The rupture disk 17 is ruptured to connect the one side and the other side when the pressure difference between the one side and the other side becomes equal to or higher than a predetermined communication pressure P. As shown in FIG. 1, the rupture disk 17 is provided in a shape that bulges from a low pressure side (second chamber R2 side) to a high pressure side (first chamber R1 side). When the pressure in the chamber R1 becomes equal to or higher than the communication pressure P (gauge pressure), a material that becomes the limit of the buckling strength of the material and reverses and buckles is used.
By providing the rupture disk 17, when the pressure in the first chamber R1 becomes equal to or higher than the communication pressure P, the first chamber R1 and the second chamber R2 communicate with each other, and the first chamber R1 to the second chamber R2 Leakage gas G is introduced to

Here, the internal volume V2 of the second chamber R2 is about 50 times to 100 times the internal volume V1 of the first chamber R1. That is, by setting the inner volume V1 of the first chamber R1 to a relatively small volume, the measurement accuracy of the gas concentration when measuring the gas concentration of the first chamber R1 by the gas concentration measuring device 18 described later is increased. Can be high. On the other hand, the internal volume V2 of the second chamber R2 is a relatively large volume. Thereby, even after the gas G in the first chamber R1 flows into the second chamber R2 after the first chamber R1 becomes equal to or higher than the communication pressure P and the rupture disk 17 bursts, the second chamber R2 is sufficient. An amount of the gas G can be stored at a low pressure, and the gas G can be appropriately prevented from being released to the atmosphere over a relatively long time.
This communication pressure P is set to a pressure approximately equal to or higher than a first inspection reference pressure P1, which will be described later, but lower than the second inspection reference pressure P2.

  As described so far, the gas leakage prevention apparatus of the present invention can appropriately prevent the leakage gas G from being diffused to the atmosphere for a relatively long time, without requiring an operator to be stationed at the site. The configuration that can prevent the leakage gas G from being released to the atmosphere is adopted.

The gas leakage preventing apparatus according to the present invention is configured to take the following usage pattern.
1 At the initial stage when gas leakage occurs, the operator is urged to check the connecting portion 12 once in a state where the leaked gas G in the first chamber R1 reaches a certain pressure (first inspection reference pressure P1). This inspection is an inspection in which a worker actually goes to the site and judges whether or not the situation should be dealt with urgently.
2 In the above situation, the gas leakage prevention device communicates the first chamber R1 and the second chamber R2 in a state where the pressure in the first chamber R1 is equal to or higher than the communication pressure P. Therefore, in this communication state, the pressure in the first chamber R1 decreases.
3 In the gas leakage prevention device of the present invention, the pressure resistance of the second chamber forming body, which is the forming member of the second chamber R2, is set lower than the pressure resistance of the first chamber forming body. For this reason, the next inspection or the start of work on the connection portion 12 is set with reference to the point in time when the pressure in the first chamber R1 and the second chamber R2 becomes the pressure resistance of the second chamber R2.

  In the gas leakage preventing apparatus of this example, a gas concentration measuring device 18 (an example of a gas concentration measuring unit) that measures the gas concentration leaked from the connection portion 12 is provided inside the first chamber R1, A control device 19 is provided for receiving a signal relating to the concentration of the gas G (hereinafter referred to as gas concentration) measured by the gas concentration measuring device 18.

The control device 19 is configured as follows to derive the gas concentration change rate and the inspection interval, which is the frequency with which the operator inspects the site, based on the received signal related to the gas concentration.
That is, the control device 19 has a map showing the correlation between the gas concentration and the gas pressure (internal pressure) in the first chamber R1, and the set gas concentration when the first chamber R1 becomes the first inspection reference pressure P1. It has a storage unit (not shown) for storing (150 ppm or more).
The control device 19 receives a signal related to the gas concentration a plurality of times during a predetermined time (30 minutes), and derives the change rate of the gas concentration. Based on the change rate of the gas concentration and the current gas concentration, the time T when the gas concentration becomes the set gas concentration, that is, the time T when the first chamber R1 becomes the first inspection reference pressure P1 is estimated. . The time T is, for example, a time after about 60 hours have elapsed since the present time. Here, the reason why the inner volume V1 of the first chamber R1 is made relatively small and the inner volume V2 of the second chamber R2 is made relatively large is that the leakage amount of the gas G from the connecting portion 12 is very small. In this case, it takes a long time for the leaked gas G to accumulate to a predetermined gas pressure in both chambers, but by making the first chamber R1 relatively small in volume, gas leakage can be derived in a relatively short time. This is because it can be done. In addition, in a state where the gas pressure of the leaking gas G is low, a more accurate measurement result can be obtained by detecting the gas concentration.

  Initially, according to the time T at which the first chamber R1 becomes the first inspection reference pressure P1, first, the worker goes to the site inspection. During this work, if it is not particularly urgent, check the situation at the site and collect appropriate information to make the necessary preparations for the next work.

  Since the change rate of the gas concentration in the first chamber R1 is confirmed on the control device 19 side, the amount of leaked gas G per unit time can be estimated based on the change rate. When the gas leakage in this state continues, the time for the first chamber R1 and the second chamber R2 to reach the second inspection reference pressure P2, which is a predetermined reference pressure, after the rupture disk 17 bursts. The required time t is estimated.

Therefore, based on the required time t, an inspection interval at which the operator inspects the site is derived. In this way, the control device 19 functions as a gas concentration change rate deriving unit and an inspection interval deriving unit.
The inspection interval is derived by dividing the required time t by the safety factor S (S is a value greater than 1). Here, the required time t and the inspection interval are calculated in the following derived example, assuming that the required time t is 41 days (984 hours) and the safety factor S is 1.64 ≦ S ≦ 1.97. Is estimated to be 500 to 600 hours.

[Derivation example of required time t]
Hereinafter, an example of a method for deriving the required time t will be described with reference to FIGS.
FIG. 5 shows the change over time in the internal pressure of the leaked gas when leaked into the first chamber R1 and the second chamber R2.
Specifically, between OA, first, the leakage gas begins to leak and shows the change over time in the internal pressure of the first chamber R1 until the interior of the first chamber R1 is fully filled. Between B, the rupture disk 17 ruptures, and the internal pressure changes with time when the leaked gas moves from the first chamber R1 to the second chamber R2. Between B and C, the leaked gas flows into the first chamber R1. And the time-dependent change in the internal pressure until the first chamber R1 and the second chamber R2 are fully filled, leaking into the first chamber R1. And shows the change over time in the internal pressures of the first chamber R1 and the second chamber R2 from when the interior of the second chamber R2 is filled up to the allowable pressure resistance of the cloth-like blocking member 16 forming the second chamber R2. ing.
The required time t corresponds to the time between OD, but the time between OA is much shorter than the time between BC and the time between CD. In the following, it is derived as the sum of the time between BC and the time between CD.
In FIG. 5, the pressure at the point A corresponds to the communication pressure P, the predetermined pressure that passes until the point A or the point A is reached corresponds to the first inspection reference pressure P1, and the pressure at the point D is the first pressure. 2 corresponds to the inspection reference pressure P2.
[Time between B and C]
First, the internal volume V1 of the first chamber R1 is obtained by subtracting the volume of the gas pipe 11 included in the first chamber R1 from the total volume inside the first chamber R1.
V1 = π / 4 × L1 ² × L2-π / 4 × L4 ² × L2
Here, L1: height of the first chamber R1 = 0.3 m
L2: width of the first chamber R1 = 0.1 m
L4: Diameter of the gas pipe 11 = 0.2 m
Then, V1≈4.0 × 10 ⁻³ m ³
Next, the internal volume V2 of the second chamber R2 is obtained by subtracting the volume of the gas pipe 11 included in the second chamber R2 and the internal volume V1 of the first chamber from the total volume inside the second chamber R2. It will be a thing. Here, it is assumed that the total volume inside the second chamber R2 is a volume of an ellipsoid having L3 as a major axis and L5 as a minor axis in FIG.
V2 = 4π / 3 × L3 / 2 × L5 / 2 × L5 / 2-π / 4 × L4 ² × L3-V1
Here, L3: long axis of the second chamber R2 = 1.0 m
L5: minor axis of second chamber R2 = 0.8 m
Then, V2≈300.0 × 10 ⁻³ m ³
Further, the inner volume V2 ′ of the second chamber R2 immediately after the rupture disc 17 has ruptured is assumed to be a boil According to Charles' law,
P × V1 = P2 ′ × (V2 ′ + V1) However, the temperature is assumed to be constant.
Assuming P = 0.3 MPa, the following equation holds because of atmospheric pressure.
(0.3 + 0.1013) × 4.0 × 10 ⁻³
= (0 + 0.1013) × (V2 ′ + 4.0 × 10 ⁻³ )
V2 '≒ 11.8 × 10 ^-3 m ³
Here, if the volume of the leaked gas that can be stored in the second chamber R2 after the rupture disk 17 bursts is V2max, V2max = V2−V2′≈288.2 × 10 ⁻³ m ³
= 72V1
Here, if the flow rate of the leaked gas is 10 ml / min, the daily leak amount is
10 ml / min × 60 × 24 = 14.4 × 10 ⁻³ m ³ / day The number of days from when the rupture disk 17 bursts until the leaked gas fills the volume V2max that can be stored in the second chamber R2 is: Under atmospheric pressure
72 × 4.0 × 10 ⁻³ /(14.4×10 ⁻³ ) = 20 days (A)

[Time between CD]
Next, the number of days in which the internal pressure of the second chamber R2 rises to the allowable pressure resistance of 0.1 MPa of the cloth-shaped blocking member 16 after the inside of the second chamber R2 is filled with leaking gas and its volume becomes V2. Is derived.
Here, the relationship between the volume V: (V1 + V2) and the leakage amount Q of the leakage gas is based on Boyle-Charles' law.
Q = V × ΔP / 0.1013 / T1
The relationship is established.
Here, Q: Leakage gas leakage amount = 10 ml / min
ΔP: differential pressure = 0.1 MPa
V: V1 + V2 = (300.0 + 4.0) × 10 ⁻³ m ³
T1: Elapsed time (min)
T1 = 304.0 × 10 ⁻³ × 10 ⁶ × 0.1 / 0.1013 / 10
≒ 300 × 10 ² min
≒ 20.8 days ... (B)

From the above, the total time from when the rupture disk 17 bursts until the internal pressure of the second chamber R2 reaches the allowable pressure resistance of 0.1 Mpa of the cloth-like blocking member 16 is
(A) + (B) ≈41 days = 984 hours And, after the rupture disk 17 has ruptured, both the first chamber R1 and the second chamber R2 are the time required to reach the second inspection reference pressure P2. t is obtained as follows, assuming the safety factor as S.
t = 984 hours / S
Here, when the range of the safety factor S is 1.64 ≦ S ≦ 1.97, the range of the required time t is 500 hours ≦ t ≦ 600 hours.

  A transmitter 21 capable of communicating with the receiver 20 is electrically connected to the control device 19. The transmitter 21 receives a signal (hereinafter referred to as an inspection promotion signal) that prompts the operator to check the gas leakage state at the inspection timing of the inspection interval derived as described above. 20 is configured to notify the operator of the inspection timing. The receiver 20 and the transmitter 21 function as communication means.

Next, the operation of the gas leakage prevention device described so far, that is, the detection of the presence or absence of gas leakage at the connecting portion 12 of the gas pipe 11 and the prevention of the release of the leaked gas G to the atmosphere are shown in the flow of FIG. Based on
The operator first installs the plate-like blocking member 15 in the connection portion 12 of the gas pipe 11 where the gas G may be leaked, and then airtightly surrounds the plate-like blocking member 15. In this manner, the cloth-like blocking member 16 is installed to form the first chamber R1 and the second chamber R2 (# 101). At this time, the plate-shaped blocking member 15 is provided with a rupture disk 17 as communication means. In addition, a gas concentration measuring device 18 that measures the gas concentration inside the first chamber R1 is provided in the first chamber R1 in a state of being electrically connected to the external control device 19.

  The gas concentration measuring device 18 measures the gas concentration inside the first chamber R1. At this time, if the gas G is leaking from the connecting portion 12 of the gas pipe 11, the gas concentration measuring device 18 measures the gas concentration and detects that there is a gas leak (# 102).

  For example, the control device 19 receives the gas concentration measured by the gas concentration measuring device 18 over a predetermined period of time, derives a first-order approximation expression based on the least squares method, etc., and changes the gas concentration in the first chamber R1. Is derived. Further, based on the derived gas concentration change rate and the current gas concentration, the time until the gas concentration in the first chamber R1 reaches the set gas concentration corresponding to the first inspection reference pressure P1 is estimated. First, a time T that requires inspection is derived (# 103).

From the viewpoint of safety, it is preferable that the worker takes measures for preventing gas leakage at the connection portion 12 by the time T. However, depending on the work situation, the work may not be performed by the time T.
On the other hand, on the gas leakage prevention device side, after the first chamber R1 rises to the communication pressure P, the first chamber R1 and the second chamber R2 enter the communication state, and the gas pressure in the device once decreases.
In this state, the control device 19 estimates the required time t described above. Here, based on the required time t, the control device 19 sets an inspection interval (t / S: where S is a value greater than 1) in which the worker expects the safety factor S (# 104).

  And the control apparatus 19 transmits the signal (henceforth an inspection promotion signal) which urges inspection of the connection part 12 from the transmitter 21 to the receiver 20 which an operator holds at the inspection timing based on the said inspection interval. (# 105). Thereby, even if it is a case where the worker is away from the site of gas leakage, the site can be inspected at an appropriate inspection timing, and safety can be improved.

[Second Embodiment]
Next, a second embodiment of the gas leakage preventing apparatus of the present invention will be described based on FIG. 3 and FIG.
The gas leakage preventing apparatus according to the second embodiment is characterized in that the communication means described in the first embodiment is configured by the relief valve 22 and the configuration relating to the promotion of inspection of the gas leakage state. Therefore, the following description will be given with an emphasis on this point, and the description of the same configuration as in the first embodiment may be omitted.

  Similarly to the first embodiment, the gas leakage prevention device of the second embodiment is a plate-shaped blocking member that hermetically surrounds the connecting portion 12 of the gas pipe 11 that flows the gas G to form the first chamber R1. 15 (an example of a first chamber forming body) and a cloth-like blocking member 16 (an example of a second chamber forming body) that forms a second chamber R2 capable of storing gas G separately from the first chamber R1. ing. The configurations of the plate-shaped blocking member 15 and the cloth-shaped blocking member 16 are the same as those in the first embodiment, and thus description thereof is omitted here.

When the internal pressure of the first chamber R1 formed by the plate-shaped blocking member 15 is equal to or higher than the communication pressure P, the partition wall 23 constituting the plate-shaped blocking member 15 has the first chamber R1 and the second chamber R2. A relief valve 22 is provided as a communication means for communicating with each other. The relief valve 22 is of a so-called umbrella type check valve type, and includes an umbrella portion 22a that energizes the communication hole 24 formed in the partition wall 23 in the vicinity thereof from the outside of the first chamber R1. ing. The umbrella portion 22a communicates with the communication hole 24 based on the relationship between the internal pressure on one side (first chamber R1 side) of the communication hole 24 and the internal pressure on the other side (second chamber R2 side) of the communication hole 24. It is what. When the first chamber R1 becomes equal to or higher than the communication pressure P (gauge pressure), the umbrella portion 22a releases the sealing bias toward the communication hole 24 and opens the communication hole 24, so that the first chamber R1 R1 and the second chamber R2 are brought into a communication state (a state indicated by a dotted line in FIG. 3).
Note that the umbrella-type relief valve 22 used as the communication means in the second embodiment is not broken even when the communication pressure P is higher than the rupture disk 17, and can be used repeatedly.

Next, in the gas leakage prevention apparatus of the second embodiment, a description will be given of a configuration that prompts inspection of the gas leakage state.
The gas leakage prevention device of the second embodiment is configured to prompt the operator to check the gas leakage state based on the internal pressure of the second chamber R2.
Specifically, the piping 25 is provided in a state communicating with the second chamber R2 with respect to the cloth-like blocking member 16 forming the second chamber R2, and the internal pressure of the piping 25 is measured. A gas pressure measuring device 26 is provided. Thereby, the gas pressure measuring device 26 can measure the internal pressure of the second chamber R <b> 2, and the measured internal pressure is sent to the control device 19.

The control device 19 stores a second inspection reference pressure P2 (a value of 0.05 MPa or more and 0.06 MPa or less) that is an allowable pressure of the second chamber R2, and the internal pressure of the second chamber R2 described above is the first pressure. 2 It is configured to be able to monitor whether or not it is larger than the inspection reference pressure P2, and the control device 19 functions as pressure monitoring means.
In the vicinity of the control device 19, a transmitter 21 capable of transmitting an inspection promotion signal that prompts the receiver 20 owned by the operator to check the gas leakage state is provided in a state of being electrically connected to the control device 19. ing. When the internal pressure of the second chamber R2 is greater than the second inspection reference pressure P2, the control device 19 transmits an inspection measurement signal from the transmitter 21 to the receiver 20. The said control apparatus 19, the receiver 20, and the transmitter 21 function as an inspection promotion means.

Next, the operation of the gas leakage prevention apparatus of the second embodiment will be described based on the flow of FIG.
As in the case of the first embodiment, the operator first installs the plate-shaped blocking member 15 for the connection portion 12 of the gas pipe 11 that may leak the gas G. Then, the cloth-like blocking member 16 is installed so as to secretly surround the plate-like blocking member 15 to form the first chamber R1 and the second chamber R2 (# 201). The partition wall 23 of the plate-like blocking member 15 is provided with a relief valve 22 as communication means.
Here, in order to provide the cloth-like blocking member 16, the worker arranges the pipe 25 in a form communicating with the second chamber R2 therein. The pipe 25 is provided with a gas pressure measuring device 26 that measures the internal pressure, and a control device 19 that is electrically connected to the gas pressure measuring device 26.

  In the second embodiment, after the relief valve 22 as the communication means brings the first chamber R1 and the second chamber R2 into communication, the gas G flows from the first chamber R1 to the second chamber R2, When the second chamber R2 reaches the second inspection reference pressure P2, the operator is urged to inspect the gas leakage state.

Therefore, in the control device 19 according to the second embodiment, the internal pressure of the second chamber R2 measured by the gas pressure measuring device 26 is received, and the internal pressure and the second inspection reference pressure P2 stored in advance are stored. Comparison is made (# 202, 203). And when the internal pressure of 2nd chamber R2 becomes larger than 2nd inspection reference pressure P2, the control apparatus 19 transmits the inspection promotion signal from the transmitter 21 to the receiver 20 which an operator holds ( # 204).
Thereby, even when the worker is away from the site of gas leakage, if the internal pressure of the second chamber R2 becomes higher than the second inspection reference pressure P2, the operator checks the gas leakage state at the site. It can be performed and safety can be secured.

[Another embodiment]
(1) In the said 1st Embodiment, the communication means was comprised as the rupture disk 17, and it comprised as the relief valve 22 in 2nd Embodiment. However, in both the first and second embodiments, the communication means exhibits its function satisfactorily regardless of which of the rupture disc 17 and the relief valve 22 is used.
Moreover, in the said 2nd Embodiment, although the relief valve 22 employ | adopted the umbrella-type check valve, even if it employ | adopts what is called a so-called duck bill, the function of this invention is exhibited well.

(2) Although the present embodiment is applied to the connection portion 12 of the gas pipe 11 which is an intermediate pressure pipe, for example, even a low pressure pipe or the like can be suitably used.

(3) In the first embodiment, the gas leakage prevention device includes the gas concentration measuring device 18 and the control device 19, and the control device 19 measures the gas in the first chamber R 1 measured by the gas concentration measuring device 18. Based on the rate of change in concentration, the time when the internal pressure of the first chamber R1 becomes the first inspection reference pressure P1 is derived, the time T at which the first inspection is performed is notified, and the first chamber R1 and the second chamber R2 The inspection interval is derived based on the required time t when the internal pressure becomes the second inspection reference pressure P2.
However, for example, an operator measures the gas concentration in the first chamber R1 using a portable gas concentration measuring device or the like, derives the rate of change from the measured gas concentration, and first calculates the change rate of the gas concentration. The time T when the internal pressure of the chamber R1 becomes the first inspection reference pressure P1 may be derived, and based on the time T, the inspection interval at which the operator should inspect the site may be derived. Then, at each inspection timing based on the inspection interval, the inspection may be promoted to a worker who is away from the site where the gas G is leaking using a communication device such as a mobile phone.

(4) In the first and second embodiments, the cloth-like blocking member 16 hermetically surrounds the plate-like blocking member 15 and both ends thereof are attached to the gas pipe 11 in close contact with the steel belt 27. The configuration is illustrated.
However, the second chamber R2 may be provided as a completely separate body from the first chamber R1, and the first chamber R1 and the second chamber R2 may be connected by a pipe provided in a state through the communication means. . In other words, the cloth-like blocking member 16 forms an independent second chamber R2, and the cloth-like blocking member 16 and the plate-like blocking member 15 are connected to each other by a pipe via the rupture disk 17. Good.

(5) In the above embodiment, the second chamber forming body can be configured by the cloth-like blocking member 16 made of vinyl chloride having a low pressure resistance. Good.

(6) In the first embodiment, according to the time T at which the first chamber R1 becomes the first inspection reference pressure P1, the worker is initially directed to on-site inspection, and then the first chamber R1 and the second chamber The required time t, which is the time required for both the chamber R2 and the second inspection reference pressure P2 to reach, is estimated, and the operator is encouraged to check at the inspection timing for each inspection interval derived based on the required time t. It was supposed to be.
However, for example, the required time t2, which is the time for the first chamber R1 to reach the first inspection reference pressure P1, is estimated, and the operator is informed at the inspection timing for each inspection interval derived based on the required time t2. It may be configured to prompt inspection.
The inspection interval in this case is derived by dividing the required time t2 by the safety factor S (S is a value greater than 1). From the viewpoint of deriving the inspection interval to the safe side, the safety factor S is calculated. It is preferable that the value is larger than the value set in the first embodiment.
Such a configuration is preferably implemented when the pressure resistance of the first chamber forming body and the pressure resistance of the second chamber forming body are set to be approximately the same.

  In the gas leakage prevention apparatus and gas leakage prevention method of the present invention, a gas leakage prevention apparatus capable of accurately detecting the presence or absence of gas leakage from the connecting portion of the gas pipe and preventing gas leakage for a relatively long period of time. It can be effectively used as a gas leakage prevention method.

G: Gas P: Communication pressure (an example of set pressure)
R1: 1st chamber R2: 2nd chamber 11: Gas pipe 12: Connection part 15: Plate-shaped interruption | blocking member (an example of 1st chamber formation body)
16: Cloth-like blocking member (an example of a second chamber forming body)
17: Rupture disc (an example of communication means)
18: Gas concentration measuring device 19: Control device 20: Receiver (an example of communication means)
21: Transmitter (an example of contact means)
22: Relief valve (an example of communication means)
23: Partition 24: Communication hole 26: Gas pressure measuring device

Claims (8)

A gas leakage prevention device comprising a first chamber forming body that hermetically surrounds a connecting portion of a gas pipe through which gas flows, and forms a first chamber,
A second chamber forming body for forming a second chamber capable of storing gas separately from the first chamber;
The gas leakage prevention device in which the first chamber forming body is provided with communication means for communicating the first chamber and the second chamber when the internal pressure of the first chamber becomes equal to or higher than a set pressure. .   The gas leak prevention device according to claim 1, wherein the second chamber forming body is made of a material having a lower withstand pressure than the first chamber forming body. Comprising gas concentration measuring means for measuring the gas concentration in the first chamber;
3. The gas according to claim 1, further comprising an inspection interval deriving unit that derives an inspection interval of a gas leakage state of the connecting portion by an operator based on a change in gas concentration measured by the gas concentration measuring unit. Leakage prevention device.   4. The gas leakage prevention device according to claim 3, further comprising a communication unit that prompts an operator to perform an inspection at an inspection timing based on the inspection interval derived by the inspection interval deriving unit. Pressure monitoring means for measuring the pressure in the second chamber;
The gas leakage according to claim 1 or 2, further comprising inspection promoting means for urging an operator to check the gas leakage state of the connecting portion when the pressure monitored by the pressure monitoring means exceeds a pressure threshold value. Prevention device. The first chamber forming body includes a partition wall that hermetically surrounds the connection portion,
The gas leakage prevention according to any one of claims 1 to 5, wherein the communication means includes a relief valve that opens and closes a communication hole formed in the partition wall, or a rupture disk provided as a part of the partition wall. apparatus. A gas leakage prevention method using the gas leakage prevention device according to claim 1 or 2,
Measuring the gas concentration in the first chamber;
A gas leakage prevention method for deriving an inspection interval of the connecting portion by an operator based on the measured change in the gas concentration.   The gas leakage prevention method according to claim 7, wherein an operator is urged to check the connecting portion at an inspection timing based on the inspection interval.

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