JPH0621830B2 - Pressure measurement method for gas transportation pipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for measuring the pressure in a transportation pipe for transporting gas such as city gas, prior to construction work or the like.

BACKGROUND ART The pressure of a transportation pipe for transporting city gas must be maintained even during construction. Conventionally, before the construction work, at least three operation holes are formed on both sides of this construction site as a check work to confirm whether the gas flow in the transport pipe is a one-sided supply or a two-sided supply. A pressure gauge or the like is connected to both ends, and a bag is inserted into the transport pipe through another operation hole to observe changes in pressure value.

Problems to be Solved by the Invention In such a prior art, it is desired to reduce the number of operation holes formed in the transport pipe and improve workability.

An object of the present invention is to provide a pressure measuring method for a gas transportation pipe, which is capable of measuring the pressure by reducing the number of operation holes to be formed in the gas transportation pipe.

Means for Solving the Problems According to the present invention, two operation holes are formed on both sides of a gas transportation pipe with a construction site interposed therebetween, one operation hole is connected with a pressure gauge, and the other operation hole is provided. Put the sealing bag near the construction site for the other operation hole, supply the fluid to the bag and inflate it so that the bag does not block the transport pipe, and observe the change in the pressure gauge. And a method for measuring the pressure of a gas transportation pipe.

In a preferred embodiment, a pair of pipes are connected to both sides of the bag, and the pipes are moved along the pipe axis direction of the transport pipe to insert and remove the bag into the transport pipe. Is characterized by.

In another preferred embodiment, another pressure gauge is connected to the other operation hole, and the pressures respectively displayed on this pressure gauge and the pressure gauge connected to the one operation hole do not change and continue. When it shows a certain value, the fluid is further supplied to the bag to completely shut off the transportation pipe, and the other bag is inserted from the one operation hole, and the fluid is supplied to the bag. It is characterized by completely blocking the transportation pipe.

Operation According to the present invention, two operation holes may be provided on both sides of the gas transport pipe for the pressure measurement, so that workability is improved. Supply fluid to the bag and inflate it so that it does not block the transport tube.
At this time, since the change of the pressure gauge is observed, the pressure can be measured without interrupting the gas transportation through the transportation pipe. At this time, if there is no change in the pressure gauge, it can be seen that gas is transported from both sides of the transportation pipe, so-called double pressure supply, at which time the bag is further expanded to shut off the transportation pipe, and the pressure gauge is connected. The bag can also be inserted through the operation hole provided to shut off the transportation pipe, and thus the transportation pipe can be constructed. When the change of the pressure gauge is observed as described above, when the pressure measured by the pressure gauge decreases and changes, gas is transported from only one of the left and right sides of the bag. It turns out that this is so-called one-sided feeding. At this time, both sides of the construction site can be connected by a bypass line to achieve the gas supply without interruption.

Embodiment FIG. 1 is a sectional view showing the basic structure of the present invention.
The present invention is preferably carried out in order to replace the transportation pipe 1 or the like at a construction site indicated by reference symbol L of the gas transportation pipe 1 for transporting city gas buried in the ground. Two operation holes 2 and 3 are formed on both sides of the transport pipe 1 with the construction point L interposed therebetween. A U-shaped water column gauge, which is a pressure gauge 4, is connected to one of the operation holes 2 to measure the pressure in the transportation pipe 1. From the other operation hole 3, the other operation hole 3
Regarding, the sealing bag body 30 is inserted near the construction site L. A pressure gauge 6 such as a U-shaped water column gauge is also connected to the operation hole 3. A fluid such as compressed air is supplied to the bag body 30 to inflate it so that the bag body 30 does not block the transport pipe 1. By observing the changes in the pressure gauges 4 and 6 at this time, it is possible to determine whether the gas supply in the transport pipe 1 is a double push or a single push as described later.

2 is an exploded perspective view of the working device 7 mounted in association with the operation hole 3, FIG. 3 is a sectional view of the working device 7, and FIG. 4 is a plan view of the working device 7. . With reference to these drawings, the working device 7 has a mounting member 8 that extends in a direction perpendicular to the pipe axis of the transport pipe 1. A mounting hole 9 and a mounting notch 10 are formed in the mounting member 8. One screw portion 12 of the U-shaped bolt 11 that surrounds the transport pipe 1 is inserted through the mounting hole 9 and screwed into the nut 13. The other threaded portion 14 of the U-shaped bolt 11 engages with the mounting notch 10,
Screw on nut 15. In this way, the mounting member 8
It is fixed to the transport pipe 1. An insertion hole 16 formed in the mounting member 8 is correspondingly air-tightly connected to the operation hole 3 formed in the transport pipe 1. The mounting member 8 is provided with a right cylindrical base 17 that is continuous with the insertion hole 16. The operation hole 3 can be opened and closed by a plug 18 made of a magnetic material, and the plug 18 can be held by a chuck 19 containing a permanent magnet or the like housed in the base body 17. The chuck 19 is connected to the lower end of the operating rod 20. The other end of the operating rod 20 is provided outside the base body 17 with the handle 2
Connected to 1. The operation rod 20 can be airtightly displaced in the axial direction and the circumferential direction of the operation rod 20 by the backing 22 on the upper portion of the base body 17. A butterfly bolt 24 is screwed into a cylinder 23 attached to the upper part of the base body 17, and by tightening the butterfly bolt 24, the operating rod 20 is displaced upward in FIG. Can be held at.

To the side wall of the base body 17, the base end portions of the guide cylinders 26 and 27 extending obliquely upward along the pipe axis direction of the transport pipe 1 are connected. The free ends of the guide tubes 26, 27 are closed by the closing members 28, 29.
Closed by. Flexible guiding bags 30 and 31 are housed in the guide tubes 26 and 27. The pair of tube bodies 32, 33 attached to the bag body 30 are inserted through the insertion holes 34, 35 formed in the closing member 28. Closing member 28
In the packing 36 installed in the guide tube 26 near the
Airtightness is achieved by inserting the tubes 32 and 33. The tubular bodies 32 and 33 are displaceable in the axial direction,
It can be angularly displaced about their axes. The tube bodies 37 and 38 are similarly connected to the other bag body 31. The tubular bodies 37 and 38 are inserted through the insertion holes 39 and 40 formed in the closing member 29. The tubular bodies 37 and 38 are displaceable in the axial direction thereof and angularly displaceable in the circumferential direction. The packing 41 achieves airtightness.

A pipe joint 42 is attached near the upper portion of the base body 17.
The pipe joint 42 is provided with a mounting cylinder 44 having a pipe joint 43 connected thereto. A pipe joint 45 facing upward is attached to the attachment cylinder 44. A pipe joint 47 is attached to the lower end of the diffusion pipe 46. The pipe joints 45, 47 are so-called pipe joints, and when the two are connected, gas can flow through, and when the two are disconnected, the pipe joint 45 is in a closed state and the mounting cylinder The gas in 44 is not diffused to the outside and is airtight. The connection and disconnection of the pipe joints 45 and 47 can be performed by a simple operation.

Insertion holes 34, 3 formed in the closing members 28, 29
5; 39, 40, as clearly shown in FIG.
In the state where the attachment member 8 is attached to the transportation pipe 1, the mounting member 8 is distributed to the left and right of the pipe axis of the transportation pipe 1. Accordingly, when the bags 30 and 31 in the guide tubes 26 and 27 are individually inserted into the transport pipe 1 from the insertion hole 16 and the operation hole 3 through the inside of the base body 17, the bags 30 and 31 are tubular bodies. 37,38; 32,3
3 touches slightly but avoids inoperability,
It is possible to smoothly insert 31 into the transport pipe 1, and it becomes easy to escape from the transport pipe 1.

A pressure gauge 6 realized by a U-shaped water column gauge or the like is attached to the mounting cylinder 44.

Referring to FIG. 5 (1), the intra-tube closing device 57 basically has a flexible bag body 30 and a flexible hole in which a through hole 66 is formed in a portion extending into the bag body 30. Pair of tubular bodies 3 having properties
2 and 33 are included. The bag body 30 is flat when no compressed air is supplied therein, and its plane is a quadrangle at right angles. The bag body 30 is made of cloth-rubber or the like. The tube bodies 32 and 33 are fixed inside the bag body 30 along the side portions 49 and 50 of the bag body 30.
33 communicates with the inside of the bag body 30. The tubular bodies 32 and 33 are flexible and relatively rigid in the axial direction, and thus the bag bodies 30 are inserted into the transport pipe 1 by pushing the tubular bodies 32 and 33. It can be made of, for example, acrylic resin. The pipe bodies 32 and 33 are connected to the air pump 53 by pipe joints 51 and 52 called a cut.

When inserting the bag body 30 into the transport tube 1, the tube body 3 is used.
2 and 33 can be wound around their axes and in mutually opposite directions to obtain the state of FIG. 5 (2) or FIG. 5 (3). This makes it easy to insert the bag body 30 into the transport pipe 1 from the guide tube 26, and at the same time, the bag body 30
Is prevented, and the bag body 30 can be easily removed from the transport pipe 1.

In the base 17 of the working device 7, the chuck 19 holding the plug 18 is set in the raised position as shown by the phantom line 25 in FIG. 3, and the bag body 30 is guided there in the state of FIG. 5 (2). Then, it is pushed into the transport pipe 1 from 26 through the base body 17 and inserted. As a result, the bag body 30 is located closer to the construction site L with respect to the operation hole 3. The state in which the bag body 30 is inserted into the transportation pipe 1 is shown in FIG. 6 (1), and the cross section perpendicular to the axis of the transportation pipe 1 is simplified and shown in FIG. 6 (2). Tube 3
2, 33 are turned in mutually opposite directions around their axes as indicated by arrows 54, 55 in FIG. 6 (3), so that the bag body 30 has at least the respective tubular bodies 32, 33. Each one is wrapped around.

Therefore, the bag body 30 is unfolded as shown in FIG. 7 (1).
In this state, the cross section perpendicular to the axis of the transport pipe 1 is as shown in FIG. 7 (2). In order to bring the bag body 30 in the state shown in FIG. 6 into the state shown in FIG. 7 (1) and FIG. 7 (2), the pipe bodies 32, 33 are set by the arrow 5 mentioned above.
Rotate in the opposite direction to 4, 55 as indicated by reference numerals 56, 57 in FIG. 7 (3). This allows the bag body 30 wound around the tube bodies 32 and 33 to be spread.

Therefore, compressed air is supplied into the bag body 30 via the pipe bodies 32 and 33 by the air pump 53 shown in FIG.
A state in which the bag body 30 is slightly swollen is shown in FIG. 8 (1), and a cross section perpendicular to the axis of the transport pipe 1 in this state is shown in FIG. 8 (2). By further supplying compressed air to the bag body 30, the bag body 30 swells as shown in FIG. 8 (3), and the pressure gauge 4 , 6 is used to observe the pressure as will be described later.

When the bag body 30 is fully inflated, the transport tube 1 can be fully closed as shown in FIG. This also applies to the other bag 31.

FIG. 10 shows an experimental result of the inventor of the present invention. In FIG. 10, the bag body 30 is inserted into the transportation pipe 1 of FIG. 1, and the bag body 3 is inserted from the state of FIG. 7 as shown in FIGS. 8 and 9.
When compressed air is supplied to 0, pressure gauge 4 or pressure gauge 6
The pressure change due to is shown. The city gas is supplied to the transportation pipe 1 from the right side in FIG. 1 at 150 mmH ₂ O at 71.8 m ³ / h. When compressed air was supplied to the bag body 30 at a constant flow rate, the pressure change by the pressure gauge 4 decreased relatively slowly as shown by the line l1.

For reference, a bag is connected to the tip of a single pipe, the bag is inserted into the transport pipe 1, and compressed air is supplied to the pipe at a constant flow rate to inflate the bag. At this time, the pressure change detected by the pressure gauge 4 is the line 12
It changes rapidly as shown by. A bag connected to the tip of a single tube is inserted into the transport tube 1 in a state of being folded by a breakable tape, and compressed air is supplied to the bag. Then, the bag body expands, the expansion force causes the tape to break, and the bag body expands in the transport pipe 1. With such a configuration, the inside of the transportation pipe 1 is blocked in a short time. Therefore, pressure gauge 4
Alternatively, it is difficult for the pressure gauge 6 to observe the change in the pressure inside the transport pipe 1 together with the inflated state of the bag body. On the other hand, according to the present invention, when compressed air is supplied to the bag body 30 at a constant flow rate, a pressure change observed by the pressure gauge 4 or the pressure gauge 6 is indicated by a line l1. It is so loose that the transport tube 1 is packed into the bag 3
The transport pipe 1 is prevented from being accidentally sealed by 0.
The risk of interrupting the transportation of gas due to is certainly eliminated.

In removing the bag body 30 from the transport tube 1 again after the bag body 30 has been used in the transport tube 1, the air pump 53 is removed from the tube bodies 32 and 33 to release the compressed air in the bag body 30 to the outside. To do. Then, one of the tubular bodies 32 and 33 is turned around its axis. As a result, the air remaining in the bag body 30 flows toward the other tube body 33 side. Thus the bag 30
It can be in a state where no air remains inside. In this way, with the bag body 30 wrapped around the one tube body 32, the tube bodies 32 and 33 are pulled, and the base body 17 is removed from the inside of the transport tube 1.
It can be returned to the inside of the guide tube 26 via.

In the above-described embodiment, when the bag body 30 is inserted into the transport pipe 1, the bag body 30 is partially wound around the pipe bodies 32 and 33, respectively. As an example, the bag body 30 may be inserted while being wound around one of the tube bodies 32 and 33.

With reference to FIG. 11, a procedure of work for cutting and exchanging the construction site L of the transportation pipe 1 will be described. First, as shown in FIG. 11 (1), the operation holes 2 and 3 are formed in the transport pipe 1, and the operation hole 2
Is equipped with a pressure gauge 4. The work device 7 is attached to the operation hole 3, and the plug 18 (see FIG. 3) that previously closes the operation hole 3 is removed by the operation of the handle 21, where the bag body 30, the tube body 32, Insert 33 into the transport tube 1 by pushing it in. The bag body 30 is inserted near the construction site L with respect to the operation hole 3. Whether or not the bag body 30 has reached the optimum position in the transport tube 1 can be known from the outside by the marks previously displayed on the tube bodies 32 and 33. Bag 30
Pressure gauge is not supplied to the pressure gauge 4
And the pressure measured by the pressure gauge 6 attached to the working device 7 are compared, and it is confirmed that the pressure values by these pressure gauges 4 and 6 are the same.

Therefore, the bag body 30 is changed from the state shown in FIG. 6 to the state shown in FIG. 7, and thereafter, compressed air is supplied into the bag body 30 by the air pump 53. As a result, the pressure values of the pressure gauges 4 and 6 are observed before the transportation pipe 1 is blocked. At this time, if neither of the pressure gauges 4 and 6 has the same pressure value and the pressure value remains the same, the gas is supplied to the transport tube 1 from both sides of the bag body 30, and so-called double-pressed supply is used. I know there is. At this time, compressed air is further supplied to the bag body 30 to close the transportation pipe 1 as shown in FIG. 11 (2). Similarly, using the working device 7, another bag 31 is inserted into the transportation pipe 1 to inflate it, and the transportation pipe 1 is closed as shown in FIG. 11 (3). The work device 7 is equipped with a diffusion pipe 46 by means of pipe joints 45 and 47. Similarly, using the working device 7a having the same configuration as the working device 7, the bags 30a and 31a are transferred from the operation hole 2 to the transport pipe 1 by using the working device 7a.
It is inserted inside and the transport pipe 1 is shut off. Since the diffusion pipe 46 is attached to the working device 7, the gas in the space inside the transportation pipe 1 closed by the bags 30 and 31 is diffused to the atmosphere, and the bags 31 and 31a and the transportation pipe 1 are also discharged. It is possible to dissipate the city gas that comes through the gap between the pipe wall and the atmosphere.
The same applies to the other working device 7a. In this way, it is possible to excise and replace the construction site L while the transport pipe 1 is blocked by the bags 30, 31; 30a, 31a.

With reference to FIG. 12, another procedure of excision and replacement work of the construction site L will be described. Using the working device 7, the bag 3 is placed inside the transport pipe 1.
The procedure up to storing 0 and inflating the bag body 30 to the extent that the transport tube 1 is not blocked is similar to the procedure described with reference to FIG. 11 above. At this time, the pressure values of the pressure gauges 4 and 6 are changed, and when it is observed that the pressure values of the pressure gauges 4 and 6 are different from each other, the transportation pipe 1
It can be understood that the gas is supplied only from one of the left and right sides of the bag body 30, that is, so-called one-sided supply. At this time, the bag body 30 is reduced and the guide tube 2 of the working device 7 is reduced.
Put back in 6 and store. Therefore, as shown in FIG.
As shown in (2), connecting holes 61 and 62 are formed outside the tube axes of the operation holes 2 and 3, and these connecting holes 61 and 62 are connected by a bypass conduit 63. In this way, with the bypass pipe 63 connected to the transport pipe 1, the working device 7 again inserts the bag body 30 into the transport pipe 1 as shown in FIG. Block the tube 1. Similarly, the bag body 31 is inserted into the transportation pipe 1 to shut off the transportation pipe 1. Further, regarding the operation hole 2, the working device 7a
And the transport tube 1 is shut off by the bags 30a and 31a. Therefore, the gas in the transport pipe 1 including the construction point L can be diffused in the same manner as described above, and the construction point L can be excised and replaced.

The present invention can be implemented not only in the context of city gas transport pipes, but also in a wide range of contexts with transport pipes for transporting other gases.

Effect As described above, according to the present invention, the pressure can be measured only by forming the two operation holes in the transport pipe, so that the workability is improved.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of a working device 7, FIG. 3 is a sectional view of the working device 7, FIG. 4 is a plan view of the working device 7, FIG. FIG. 5 is a plan view showing the bag body 30 and the tube bodies 32, 33, etc., and FIGS. 6, 7, and 8 are views for explaining a procedure for inflating the bag body 30 in the transport pipe 1, 9 FIG. 10 is a cross-sectional view showing a state in which the transport pipe 1 is blocked by the bag body 30, FIG. 10 is a graph showing experimental results, and FIG. 11 is a cross-sectional view for explaining a procedure for measuring the pressure of the transport pipe 1. , FIG. 12 is a sectional view for explaining another procedure for measuring the pressure of the transport pipe 1. 1 ... Transport pipe, 2, 3 ... Operation hole, 4, 6 ... Pressure gauge,
7 ... Working device, 17 ... Base, 26, 27 ... Guide tube, 30, 30a; 31, 31a ... Bag, 32, 3
3; 37, 38 ... Tube, 53 ... Air pump, 57 ...
… In-pipe closure

Claims (3)

[Claims] 1. An operation hole is formed on both sides of a gas transportation pipe, sandwiching a construction site, and a pressure gauge is connected to one operation hole.
From the other operation hole, place the sealing bag near the construction site with respect to the other operation hole, supply the fluid to the bag, and inflate it so that the bag does not block the transport pipe. A method for measuring pressure in a gas transport pipe, which comprises observing a change in a meter. 2. A pair of pipe bodies are connected to both sides of the bag body, and each pipe body is moved along the pipe axis direction of the transport pipe to insert and remove the bag body into the transport pipe. The pressure measuring method for a gas transportation pipe according to claim 1, wherein 3. Another pressure gauge is connected to the other operation hole, and the pressures respectively displayed on this pressure gauge and the pressure gauge connected to the one operation hole do not change and remain constant. Value, the fluid is further supplied to the bag to completely shut off the transport tube, and another bag is inserted from the one operation hole, and the fluid is supplied to the bag to transport the tube. The method for measuring pressure of a gas oil supply pipe according to claim 1, wherein the pressure is completely shut off.