JPH06100517B2 - Pipe leakage detection mechanism - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement of a pipe leakage detection mechanism, and more specifically, it can detect abnormal pressure on the secondary side and, of course, a small amount of gas such as a pipe on the secondary side. The present invention also relates to a pipe leakage detection mechanism that can surely detect leakage in a short time.

(Prior Art) As a conventional pipe leakage detection mechanism G, as shown in FIG. 6, one provided on the outside of the flow chamber 10 is known. The distribution chamber 10 is connected to the primary side 10 by the valve nozzle 11.
It is divided into ₁ (upstream side) and secondary side 10 ₂ (downstream side). The primary side 10 ₁ is the gas inlet 12 and the secondary side 10 ₂ is the gas outlet 13
It has become. The inflow port 12 is connected to a gas supply source, and the outflow port 13 is connected to a gas combustor or the like via a pipe or the like. Further, the valve nozzle 11 is adapted to be opened and closed by the valve body 40.

Piping leakage detecting mechanism G by detecting the pressure P ₂ on the secondary side 10 ₂ of the gas has a structure having a secondary-side pressure detection mechanism 80 for detecting the leakage or the like of gas.

This secondary side pressure detection mechanism 80 has an outlet hole as shown in the drawing.
It has a secondary side pressure detection chamber 70 communicating with 13 via a communication hole 72, and this secondary side pressure detection chamber 70 is closed by a secondary side pressure detection diaphragm D ₁ . That is, the pressure P ₂ on the secondary side 10 ₂ acts on one surface of the secondary side pressure detection diaphragm D ₁ . On the other hand, a secondary pressure detection mechanism 80 is provided on the other surface of the secondary pressure detection diaphragm D ₁ .

This secondary side pressure detection mechanism 80 includes an elastic body receiving member 81, a spring 82 which applies a pressing force to the secondary side pressure detection diaphragm D ₁ with the elastic body receiving member 81 as a fulcrum, and an elastic body receiving member 81. And a secondary side pressure detection diaphragm
An abutting body 84 that moves together with D ₁ and is movable in the tubular body 83, a magnet M provided on the abutting body 84, and a tubular body 83 that is turned on when the magnet M approaches. It is provided with a reed switch R that acts as an OFF.

(When detecting abnormal pressure on the secondary side) When the pressure of the supply gas falls below a predetermined pressure, the pressing force of the spring 82 causes the secondary side pressure detection diaphragm D ₁
Moves to the left side in the drawing, and the magnet M which is linked to this moves away from the reed switch R, the reed switch R is turned on or off, and the pressure drop of the supply gas is detected.

(When Detecting Leakage of Pipe etc. on the Secondary Side) The valve nozzle 11 is once closed by the valve element 40, and a decrease in the secondary side gas pressure after a predetermined time has elapsed is detected. That is,
As shown in FIG. 7, if there is a gas leak somewhere in the pipe A, the gas meter B, the cock C, the combustor D, etc. on the downstream side of the pipe leakage detection mechanism G, the pressure of the secondary side gas decreases, As described above, the secondary side pressure detection mechanism 80 works to detect the gas leakage of the piping or the like on the secondary side.

Therefore, there are the following problems. That is, unless the pressure due to gas leakage from the piping on the secondary side falls below the operating set pressure of the secondary pressure detection mechanism 80, gas leakage from the piping on the secondary side cannot be detected.

As a result, as shown in FIG. 8, when the amount of leaking gas is large, it can be detected in a relatively short time, but when the amount of leaking gas is small, it takes a very long time to detect the leak. At present, it takes time and is virtually undetectable.

(Object of the Invention) The present invention has been studied to solve the above-mentioned problems,
It has been achieved.

Therefore, an object of the present invention is to provide a pipe leakage detection mechanism capable of surely detecting a slight gas leak such as a pipe on the secondary side in a short time as well as detecting a secondary side pressure abnormality. To do.

(Structure of the Invention) That is, the present invention relates to a flow chamber formed by a side wall, a valve nozzle provided so as to divide the flow chamber into an upstream-side primary side and a downstream-side secondary side, and this valve. A valve body arranged to open and close the nozzle, a differential pressure detection diaphragm provided outside the flow chamber so as to separate the side wall, and detecting a differential pressure between the primary side and the secondary side, A differential pressure detection diaphragm, and a secondary side pressure detection diaphragm provided so as to be adjacent to the differential pressure detection diaphragm,
One surface of the differential pressure detection diaphragm is communicated with the primary side of the flow chamber, and between the other surface of the differential pressure detection diaphragm and one surface of the secondary pressure detection diaphragm facing the other surface. Is communicated with the secondary side of the flow chamber, the other side of the secondary side pressure detection diaphragm is opened to the atmosphere side, and when the valve nozzle is opened, the secondary side pressure detection diaphragm causes abnormal pressure on the secondary side. When the valve nozzle is closed, the differential pressure detection diaphragm detects the pressure drop on the secondary side with respect to the primary side to detect gas leaks in the pipes communicating with the secondary side. .

(Operation of the Invention) In the present invention, (a) the abnormal pressure on the secondary side is detected when the valve nozzle is opened and normal gas is used. That is, when the pressure on the secondary side abnormally drops due to gas leakage during use of gas, one surface side (secondary side) of the secondary side pressure detection diaphragm and the other surface side (atmosphere side) As a result, the pressure balance of the above is lost, and the secondary side pressure detection diaphragm moves. Therefore, the abnormal pressure on the secondary side can be detected by the movement of the secondary side pressure detection diaphragm.

(B) In addition, for a slight gas leak in a pipe or the like that cannot be detected in a normal use state, the valve nozzle is closed by the valve body, and the state of the subsequent pressure drop on the secondary side is detected.

In this case, when the valve nozzle is closed, the pressure on the primary side acts on one surface of the differential pressure detection diaphragm, and the pressure on the secondary side acts on the other surface. If the pressure decreases even a little, the pressure on the primary side, that is, the high pressure side, pushes the differential pressure detection diaphragm to the secondary side. Therefore, the differential pressure detection diaphragm moves even with a slight gas leak on the secondary side. That is, even a slight gas leak on the secondary side can be detected.

(C) Since the secondary side pressure detection diaphragm and the differential pressure detection diaphragm are provided facing and adjacent to each other, it is possible to arrange these diaphragms in an extremely narrow space as compared with the case where they are provided individually. it can.

Embodiments of the Invention The present invention will be specifically described below with reference to the drawings by embodiments.

1 to 5 show a pipe leakage detection mechanism according to an embodiment of the present invention, and FIG. 1 is a main part, that is, a secondary pressure detection chamber, a secondary pressure detection mechanism, a primary pressure detection chamber, and a primary pressure detection chamber. Explanatory drawing which notched a part which shows the differential pressure detection mechanism of the secondary side and the secondary side, 2nd
FIG. 4 is an explanatory view showing a process of changing the pressure detected by the secondary side pressure detection diaphragm D, FIG. 3 is an explanatory view in which a part of a main portion in a valve closed state is cut away, and FIG. 4 is a valve opened state. FIG. 5 is a partially cutaway explanatory view showing a main part, and FIG. 5 is a partially cutaway explanatory view showing a valve operating mechanism and an operating mechanism of a manually operated rod.

In FIG. 1, E is a pipe leak detection mechanism according to an embodiment of the present invention. The pipe leak detection mechanism E includes a distribution chamber 10 formed by a side wall 14 and a primary side on the upstream side of the distribution chamber 10. 10 ₁ and the downstream side of the secondary side 10 ₂ and the valve nozzle 11 provided to divide the piping has been the valve body 40 (FIG. 3, reference FIG. 4) so as to open and close the valve nozzle 11 and The sidewall 14
And a differential pressure detection diaphragm D ₂ provided outside the flow chamber 10 so as to separate the differential pressure detection diaphragm D ₂ for detecting the differential pressure between the primary side 10 ₁ and the secondary side 10 ₂ and facing the differential pressure detection diaphragm D ₂ . And a secondary pressure detection diaphragm D ₁ provided so as to be adjacent to each other, and the differential pressure detection diaphragm.
One surface of D ₂ is communicated with the primary side 10 ₁ of the flow chamber 10,
Between the other surface of the differential pressure detection diaphragm D ₂ and one surface of the secondary side pressure detection diaphragm D ₁ facing the other surface is communicated with the secondary side 10 ₂ of the flow chamber 10, The gist is that the other surface of the secondary pressure detection diaphragm D ₁ is open to the atmosphere side.

That is, the flow chamber 10 is connected to the primary side 10 ₁ via the valve nozzle 11.
There has a flow inlet 12, the secondary side 10 ₂ is in the outlet port 13. A valve actuating mechanism housing chamber 30 having a valve actuating mechanism 20 therein is provided at a position facing the valve nozzle 11 with respect to the flow chamber 10 (see FIG. 5). The valve body 40 is
It is adapted to be actuated by the valve actuation mechanism 20. Further, one surface side of the secondary pressure detection diaphragm D ₁ is a secondary pressure detection chamber 70, and the secondary pressure detection mechanism 80 is arranged on the other surface side of the diaphragm D _1. There is. The secondary pressure sensing chamber 70 communicates with the secondary side 10 ₂ through the communication hole 72. Further, this secondary side pressure detection chamber 70 has a communication hole 74
Through the other side of the differential pressure detection diaphragm D ₂ . That is, the other surface side of the differential pressure detection diaphragm D ₂ is also the secondary side pressure detection chamber 70. The secondary pressure detection chamber 70 is provided with a differential pressure detection mechanism 100 that detects the displacement of the differential pressure detection diaphragm D ₂ to detect the differential pressure between the primary side 10 ₁ and the secondary side 10 _2. There is. Further, one surface side of the differential pressure detection diaphragm D ₂ is a primary side pressure detection chamber 90, and this primary side pressure detection chamber 90 communicates with the primary side 10 ₁ via a communication hole 91.

Then, the secondary side pressure detection mechanism 80 has an elastic body 82 (in this embodiment, a spring is used as the elastic body 82 in the other surface of the secondary side pressure detection diaphragm D ₁ via the elastic body receiving portion 81. Since this is referred to as a spring 82 hereinafter), this spring 82 allows the secondary side pressure detection diaphragm D ₁
It is configured so that a predetermined pressing force can be applied to. In addition, the differential pressure detection mechanism 100 includes a differential pressure detection diaphragm D ₂
An elastic body 102 (in this embodiment, a spring is used as the elastic body 102 in the present embodiment, hereinafter referred to as a spring 102) is arranged on the other surface of the elastic body receiving member 101. It is configured so that a predetermined pressing force can be applied to the detection diaphragm D ₂ .

This structure will be further described. In this embodiment, the secondary side pressure detection diaphragm D ₁ and the differential pressure detection diaphragm are used.
D ₂ is located outside the side wall 14 and includes a first auxiliary wall 73 ₁ and a second auxiliary wall 7 1.
It is detachably attached via 3 ₂ . The primary pressure detection chamber 90 is formed by the differential pressure detection diaphragm D ₂ and the first auxiliary wall 73 ₁ , and each of the diaphragms D ₁ and D ₂ is formed.
The secondary side pressure detection chamber 70 is placed in the portion of the second auxiliary wall 73 ₂ sandwiched between
Are formed. The communication hole 72 is formed in the side wall 14, the first auxiliary wall 73 ₁ and the second auxiliary wall 73 ₂ , the communication hole 74 is formed in the second auxiliary wall 73 ₂ , and the communication hole 91 is formed in the first auxiliary wall 73 _1. Is formed in. However, the communication hole 91 is communicated directly to the primary side 10 ₁ through the through hole formed in the side wall 14.

Further, the differential pressure sensing mechanism 100, an elastic member receiving member 10 mounted for position adjustment by suitable means to a ₂ second auxiliary wall 73
1, slidably fitted inside the elastic body receiving member 101,
An abutting body 103 whose one end is connected to the other surface of the differential pressure detecting diaphragm D ₂ , and the abutting body 103 and the elastic body receiving member.
And the spring 102 which allowed interposed between the 101, the reed switch R ₂ provided in the second auxiliary wall 73 _2, provided on one end side of the abutting member 103, the differential pressure sensing diaphragm D ₂ second magnet M2 to oN or OFF the reed switch R ₂ close to the reed switch R ₂ when it is moved to the auxiliary wall 73 ₂ side
It has and.

Therefore, when detecting the leakage of the piping in the secondary side 10 _2, once close the valve nozzle 11 in the valve body 40, if, downstream of the pipe from the pipe leakage detection mechanism E, a gas meter, cock, combustor, etc. somewhere there is a gas leak, the gas pressure P ₂ on the secondary side 10 ₂ of the distribution chamber 10 is lowered even a little, the pressure P ₂ of the pressure P ₁ of the primary side 10 ₁ and the secondary side 10 ₂ of the difference occurs, i.e. the pressure difference is generated in the primary side pressure detecting chamber 90 the secondary pressure sensing chamber 70, the differential pressure sensing diaphragm 10 ₂ against the repulsive force of the spring 102 the secondary pressure sensing chamber 70 Move to the side (move to the left in the figure).

Then, the magnet M ₂ attached to the contact body 103 approaches the reed switch R ₂ attached to the second auxiliary wall 73 ₂ , and the reed switch R ₂ is turned on or off.
It becomes, thereby detecting the gas leakage of the pipe or the like in the secondary side 10 _2.

In this case, the pressure P ₁ always in the primary-side pressure detecting chamber 90 primary side 10 _1, that is, the high pressure gas acts, the secondary side
Differential pressure detection diaphragm 1 even if 10 ₂ gas slightly leaks
A large differential pressure acts on 0 ₂ . Therefore, even if the amount of leaking gas is small, the leak of gas can be detected reliably in a short time.

Next, the structure of the secondary pressure detection mechanism 80 will be described.

As shown in FIG. 1, the secondary side pressure detection mechanism 80 includes a second auxiliary wall 73 on the other surface side of the secondary side pressure detection diaphragm D _{1.
2 and the} like, and a plurality of elastic body receiving members that are screwed onto the outer peripheral portion of the cylinder 83 at intervals in the axial direction.
81, a contact body 84 slidably fitted inside the cylindrical body 83, and one end of which is connected to the other surface of the secondary side pressure detection diaphragm D ₁ , and the contact body 84 and the above A spring 82 independently interposed between each elastic body receiving member 81,
Of these springs 82, a spring pressing force selecting member 85 for selecting the spring 82 on which the pressing force acts on the secondary side pressure detection diaphragm D ₁ , and a magnet M provided at the other end of the contact body 84. _1, so as to face the magnet M _1, fixedly provided at a predetermined position, the approach of the magnet M _1, and a reed switch R ₁ switched to oN or OFF.

Further explaining this structure, the elastic body receiving member 81,
In the present embodiment, two first elastic body receiving members 81a and a second elastic body receiving member 81b provided behind this are arranged, and the first elastic body receiving member 81a is arranged. A first spring 82a is interposed between the contact body 84 and the contact body 84, and a second spring 82b is independently interposed between the second elastic body receiving member 81b and the contact body 84.

The number of the elastic body receiving member 81 and the number of the springs 82 described above is two in the present embodiment. However, it is needless to say that the number may be appropriately increased if necessary.

In the present embodiment, the spung pressing force selecting member 85 is, as shown in FIGS. 1 and 2, the second elastic body receiving member 81.
b and are brought into correspondence, a plurality of those in the second auxiliary wall 73 ₂ is attached by screws 86.

Therefore, if you want to grant the pressing force of only the first spring 82a to the secondary-side pressure sensing diaphragm D _1, as shown by the solid line in FIGS. 1 and 2, the spring pressing force selection member 85
The second spring 82b is set so as to be restrained by the spring pressing force selecting member 85 so that the pressing force of the second spring 82b does not act on the diaphragm D ₁ .

Further, when the pressing force of the first spring 82a and the pressing force of the second spring 82b are to be combined and applied to the secondary side pressure detection diaphragm D ₁ , the spring pressing force selection member 85 is rotated as shown by the dotted line in FIG. At the very least, the pressing force of the second spring 82b should act on the diaphragm D ₁ .

Therefore, the pressing force acting on the other surface of the secondary side pressure detection diaphragm D ₁ can be changed simply by selecting each spring as required, and the secondary side can be selected according to the type of gas used. The pressure at which the pressure detection diaphragm D ₁ operates can be easily and accurately changed at the installation site.

As a result, the production line, quality control, inventory control, etc. can be simplified, while the inventory quantity can be greatly reduced, and the cost can be reduced.

In addition, it is not necessary to bring many types of piping leak detection mechanisms to the installation site like the conventional ones, so it is possible to reduce the cost of installation work, adjustment is easy and advanced technology is not required, There is no risk of mistaken spring replacement.

Further, since the secondary side pressure detection diaphragm D ₁ and the differential pressure detection diaphragm D ₂ face each other and are adjacent to each other, these diaphragms D ₁ and D ₂ are different from each other as compared with the case where they are individually provided. The installation space for D ₁ and D ₂ can be saved. That is, it is possible to provide a very small pipe leakage detection mechanism.

Next, the valve body 40 described above will be described with reference to FIGS. 3 and 4.

As shown in the present embodiment, the valve body 40 includes a first valve body 41 that opens and closes the valve nozzle 11 and a slave valve nozzle 42 provided in the first valve body 41, which is operated by the plunger P. It is composed of a second valve body 43 that opens and closes and operates the first valve body 41.

That is, the first valve body 41 constituting the valve body 40 is provided with a through hole 44 penetrating the upper and lower surfaces in the central portion, and the sub valve nozzle 42 is fitted in the through hole 44. is there.

Further, the second valve body is surrounded by surrounding the sub valve nozzle 42.
A second valve body mounting member 45 for mounting the 43 up and down is detachably screwed.

As shown in the figure, the second valve body mounting member 45 has an inwardly projecting step portion 45a formed in the middle portion thereof, and a gas circulation hole 46 is formed in the lower peripheral portion thereof at intervals. ing.

Further, on the lower surface of the above-mentioned first valve body 41, the valve nozzle
A seal member made of a rubber-like elastic material at a position corresponding to 11.
47 is fitted.

Next, the second valve body 43, which is mounted in the second valve body mounting member 45 of the first valve body 41 so as to be capable of moving up and down, has a rubber-like elasticity at a position corresponding to the slave valve nozzle 42 on the lower surface. A seal member 48 composed of a body is fitted, and a mounting portion 49 for mounting the lower end of the plunger P is provided at the center of the upper portion.

And, as shown in the figure, this second valve body 43 is
The valve body mounting member 45 is mounted so as to be able to move up and down via a second valve body pressure-lowering spring 43a.

Therefore, when the valve body 40 is opened, if the plunger P is pulled up, first, the second valve body 43 is pulled up against the pressing force of the second valve body lowering spring 43a, and the slave valve nozzle 42 is opened. Then, the first valve body 41 can be pulled up to open the valve nozzle 11, and the gas can flow.

As described above, in this embodiment, the plunger P
However, first, the second valve body 43 is pulled up against the pressing force of the second valve body pressure lowering spring 43a to open the slave valve nozzle 42. Therefore, the slave valve nozzle 42 is opened to the upstream side. That is, the gas can be discharged from the high-pressure gas supply side toward the downstream side of the secondary pressure, and the upstream gas pressure and the downstream gas pressure can be substantially balanced in advance.

Therefore, the valve body 40 can be opened with a smaller amount of energy as compared with the above-described conventional pipe leakage detection mechanism.

Further, in the present embodiment, when the second valve body 43 is pulled up, the flange portion 43b formed on the lower peripheral edge of the second valve body 43 strikes the step portion 45a of the second valve body mounting member 45. As a result, the valve opening operation described above can be promoted.

Next, the valve actuating mechanism 20 will be described with reference to FIG.

As shown in this embodiment, the valve actuating mechanism 20 includes a solenoid S, an actuating mechanism T of a manually operated rod M arranged above the solenoid S, and an actuating mechanism of the solenoid S and the manual operated rod M. And a plunger P operated by T.

The solenoid S fits the plunger holder 22 on the upper part of the plunger slide tube 21 into which the plunger P is slidably inserted, via the gas seal member 51 (O ring in this embodiment). , Plunger sliding tube above
The permanent magnet 23 is arranged around the lower part of the 21, and the solenoid coil 24 is arranged around the middle part.

The upper part of the plunger P is formed in a convex shape as shown in the drawing, and the upper end of the plunger P has a manual operation rod M penetrating the plunger holder 22 and having a display Ma at the top. There is. Further, the above-mentioned valve element 40 is detachably attached to the lower end of the plunger P via a valve rod 25.

Also, the upper casing that forms the valve actuating mechanism storage chamber 30.
A solenoid mounting holder 60 is attached to the lower surface of 31 via a gas seal member a (O ring in this embodiment) so as to cover the lower surface of 31 and the upper surface of the first valve body 41. The first valve body pressing spring 61 is attached between the two.

Next, the valve actuating mechanism 20 described above is actuated to operate the valve element described above.
The case of closing 40 and the case of opening 40 will be described.

(When closing the valve) When a gas cutoff pulse signal is sent to the solenoid S described above, the magnetic field of the solenoid coil 24 forms a circuit opposite to the magnetic field circuit of the permanent magnet 23, and as a result, the attraction force of the permanent magnet 23. And the plunger P to which the valve element 40 is attached is lowered by the pressing force of the valve element pressing spring 61.

Then, first, the valve body 40 is pressed against the valve nozzle 11 to close the valve nozzle 11, and at the same time, the second valve body 43 descends due to the pressing force of the second valve body lowering spring 43a. The slave valve nozzle 42 is closed to completely shut off the gas flow.

(When opening the valve) When a gas flow pulse signal is sent to the solenoid S,
The magnetic field of the solenoid coil 24 forms a magnetic field circuit in the same direction as the magnetic circuit of the permanent magnet 23, the attracting force of the solenoid S increases, and the plunger P rises.

Then, first, the second valve body 43 is pulled up against the pressing force of the second valve body pressure reducing spring 43a, and the slave valve nozzle 42 is opened.
Subsequently, the plunger P further rises against the pressing force of the first valve body pressing spring 61, and the first valve body 41 moves to the valve nozzle.
11 is opened and gas is circulated.

Next, the operating mechanism T of the manual operation rod M attached to the upper end of the plunger P as described above will be described.

As shown in FIG. 5 in the present embodiment, the actuation mechanism T of the manual operation rod M includes a post nut 26 screwed onto the plunger holder 22 of the solenoid S via a gas seal member 52, and this post. Gas seal member for nut 26
Manual button 27 loosely inserted so that it can be raised and lowered via 53
And a spring 28 that gives a return function to the manual button 27, and a spring holder 29 that houses the spring 28.

To explain this structure further, the above manual button 27
As shown in the figure, an engaging member internally formed with an engaging portion A that engages with the neck of the display Ma provided on the top of the manual operation rod M when the manual operation rod M is pulled up. 27a is provided, and a spring receiver 27b that receives the spring 28 is provided on the outside.

The manual button 27 described above is made of a transparent synthetic resin in this embodiment so that the display portion Ma of the manual operation rod M can be seen from the outside.

As shown in the figure, the spring 28 is composed of an upper spring 28a and a lower spring 28b, and the upper spring 28a includes a collar portion 29a formed on the top of the spring holder 29 and the manual button 27. Install it between the spring holder 27b and the lower spring 28b
Is the spring holder 27b and the spring holder 29.
It is mounted between a collar portion 29b formed on the bottom of the.

A cap 32 is detachably screwed onto the top of the upper casing 31 via a gas seal member 54. In the present embodiment, the cap 32 is molded of transparent synthetic resin, and is the display portion of the manual operation rod M described above.
Ma can be seen from the outside.

Since the operating mechanism T of the manual operation rod M is configured as described above, when shutting out the outflow of gas by manual operation, first, the cap 32 is removed from the top of the upper casing 31, and then, The manual button 27 is pressed to lower it, and the manual operation rod M is lowered.

Then, the upper part of the plunger P is separated from the plunger holder 22, the attraction force between the plunger holder 22 and the plunger P is reduced, and the plunger P with the valve element 40 attached is lowered by the pressing force of the valve element pressing spring 61. Then, the valve body 40 is brought into pressure contact with the valve nozzle 11 to block the flow of gas.

When the gas is to be circulated by manual operation, first, the cap 32 is removed from the top of the upper casing 31 as described above, and then the manual button 27 is pulled up so that the plunger P is attracted to the plunger holder 22. Raise to the area.

Then, the attraction force of the plunger holder 22 raises the plunger P against the pressing force of the valve body pressing spring 61, and the valve body 40 opens the valve nozzle 11 to allow the gas to flow.

Further, in the present embodiment, the gas sealing means for preventing the leakage of gas from the flow chamber 10 to the valve actuation mechanism housing chamber 30 is, as described above, the upper portion of the plunger sliding tube 21 and the plunger holder 22. The gas seal member 51 (O ring in this embodiment) provided between the plunger holder 22 and
Gas seal member provided between the upper part of the and the post nut 26
52 (O ring in this embodiment) and gas seal member 53 (O ring in this embodiment) provided between the post nut 26 and the manual button 27.

As described above, in this embodiment, each gas seal member is not provided on the sliding portion of the plunger P at all.

Therefore, when the plunger S is operated by the solenoid S, the operating performance of the solenoid S can be greatly improved, while the gas seal members 51, 52, 53 do not come into direct contact with the gas, so that the gas seal members 51 are not directly contacted. 52, 53 does not change in hardness due to the decrease in gas temperature, and the operating resistance of the plunger P does not increase. As a result, the valve actuating mechanism such as the solenoid can be further downsized in cooperation with the above-described present invention, and the cost can be reduced.

Also, when the plunger P is operated by the manual operation rod M, since the operation resistance of the plunger is small as described above, the manual operation can be facilitated and ensured.

(Effects of the Invention) According to the present invention, (a) the abnormal pressure on the secondary side is detected when the valve nozzle is opened and normal gas is used. That is, when the pressure on the secondary side abnormally drops due to gas leakage during use of gas, one surface side (secondary side) of the secondary side pressure detection diaphragm and the other surface side (atmosphere side) As a result, the pressure balance of the above is lost, and the secondary side pressure detection diaphragm moves. Therefore, the abnormal pressure on the secondary side can be detected by the movement of the secondary side pressure detection diaphragm.

(B) In addition, for a slight gas leak in a pipe or the like that cannot be detected in a normal use state, the valve nozzle is closed by the valve body, and the state of the subsequent pressure drop on the secondary side is detected.

In this case, when the valve nozzle is closed, the pressure on the primary side acts on one surface of the differential pressure detection diaphragm, and the pressure on the secondary side acts on the other surface. If the pressure decreases even a little, the pressure on the primary side, that is, the high pressure side, pushes the differential pressure detection diaphragm to the secondary side. Therefore, the differential pressure detection diaphragm moves even with a slight gas leak on the secondary side. That is, even a slight gas leak on the secondary side can be detected.

(C) Since the secondary side pressure detection diaphragm and the differential pressure detection diaphragm are provided facing and adjacent to each other, it is possible to arrange these diaphragms in an extremely narrow space as compared with the case where they are provided individually. it can.

[Brief description of drawings]

1 to 5 show a pipe leakage detection mechanism according to an embodiment of the present invention, and FIG. 1 is a main part, that is, a secondary pressure detection chamber, a secondary pressure detection mechanism, a primary pressure detection chamber, and a primary pressure detection chamber. Explanatory drawing which notched a part which shows the differential pressure detection mechanism of the secondary side and the secondary side, 2nd
FIG. 4 is an explanatory view showing a process of changing the pressure detected by the secondary side pressure detection diaphragm D, FIG. 3 is an explanatory view in which a part of a main portion in a valve closed state is cut away, and FIG. 4 is a valve opened state. FIG. 5 is a partially cutaway explanatory view showing a main part, FIG. 5 is a partially cutaway explanatory view showing a valve operating mechanism and an operating mechanism of a manual operation bar, and FIG. 6 is a conventional pipe leakage detecting mechanism. FIG. 7 is an explanatory view showing a main part with a part cut away, FIG. 7 is an explanatory view showing an example of a gas pipe, and FIG. 8 is a view showing a relationship between gas leakage and gauge pressure. 10 …… Flow chamber, 11 …… Valve nozzle, 12 …… Flow chamber inlet, 13 …… Flow chamber outlet, 14 …… Side wall, 20 …… Valve operating mechanism, 30 …… Valve operating mechanism storage chamber , 40 ...... Valve body, 70 ...... Secondary pressure detection chamber, 72 ...... Communication hole, 73 ₁ ...... First auxiliary wall, 7
3 ₂ …… Second auxiliary wall, 80 …… Secondary side pressure detection mechanism, 81 ……
Elastic body receiving member, 82 ...... Elastic body, D ₁ ...... Secondary side pressure detection diaphragm, 90 ...... Primary side pressure detection chamber, 91 ...... Communication hole,
100 …… Primary side and secondary side differential pressure detection mechanism, 101 …… Elastic body receiving member, 102 …… Elastic body, D ₂ …… Primary side and secondary side differential pressure detection diaphragm.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenya Nakamura 23 Minamikashima, Futamachi, Tenryu-shi, Shizuoka Prefecture (72) Chihiro Okebaya 23 Minamikashima, Futamachi, Tenryu-shi, Shizuoka Prefecture

Claims (1)

[Claims] 1. A flow chamber formed by a side wall, a valve nozzle provided to divide the flow chamber into an upstream primary side and a downstream secondary side, and a valve nozzle for opening and closing the valve nozzle. A disposed valve body, a differential pressure detection diaphragm that is provided outside the flow chamber so as to separate the side wall, and detects a differential pressure between the primary side and the secondary side, and faces the differential pressure detection diaphragm. And a secondary pressure detection diaphragm provided so as to be adjacent to each other, one surface of the differential pressure detection diaphragm is communicated with the primary side of the flow chamber, the other side of the differential pressure detection diaphragm. The surface and one surface of the secondary pressure detection diaphragm facing the other surface are communicated with the secondary side of the flow chamber, and the other surface of the secondary pressure detection diaphragm is opened to the atmosphere side. The valve nozzle When opening, the secondary side pressure detection diaphragm detects abnormal pressure on the secondary side, and when the valve nozzle is closed, the differential pressure detection diaphragm detects pressure drop on the secondary side with respect to the primary side and connects to the secondary side. A pipe leakage detection mechanism characterized by detecting gas leakage such as.