JP3525005B2 - Leak detection method for existing piping system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an existing piping system laid as a gas pipe, a water pipe, etc., and relates to a method for detecting a leak portion occurring in the pipe, and particularly to a flexible and flexible system. The present invention relates to a leak detection method for an existing piping system in which a tube is inverted and inserted into a pipe so that a leak portion generated in a pipe of an inspection path can be detected.

[0002]

2. Description of the Related Art Various techniques have been proposed so far for detecting a leakage portion such as a corrosion hole generated in an existing piping system. For example, JP-A-63-101746 (Japanese Patent Publication No. 4-63329) and JP-A-63-1.
According to Japanese Patent No. 20237, as a relatively simple leak detecting means, a leak detecting pig or a hollow hermetic plug is inserted into a pipe, and this is moved in the pipe in a constricted state, and then expanded at a predetermined position. There is known a method in which the inside of the pipe in the inspection section is hermetically sealed and the pressure change in the pipe in the sealed section is detected to detect the presence or absence of leakage.

[0003]

However, in the case of detecting the presence or absence of leakage by detecting the pressure change in the pipe in the sealed section as described above, the conventional method has the following problems.

As a means for forming a sealed section, in the case of a system for sealing a pipe by inserting a leak detecting pig or a hollow hermetic plug from one opening of the pipe, the pig and the hollow hermetic plug are first There is a problem that it becomes impossible to insert it because it is caught in a step inside the pipe of a curved pipe portion such as an elbow interposed in the pipe line. Further, as a method of introducing the pig or the hollow plug into the pipe, when a traction material is used, the traction material must be inserted into the pipe in advance, which not only increases the number of working steps, but especially bends such as elbows. When there are many tractors, it is difficult to properly insert the traction material. Furthermore, when introducing a pig or a hollow seal into the tube while pushing it with a coil wire or other insertion material, there is a problem with the insertion ability of the insertion material into the tube, and there is a certain limit to the length of the insertion material. There was a problem that the road section could not be set long. Therefore, a large number of work shafts for inspection must be created, which causes a problem that the work cost becomes expensive.

In view of the above-mentioned problems, the present invention provides an existing piping system in which the pipeline section of the inspection path can be set relatively long, and in particular, the position where the leak portion of the piping system having many bends can be accurately specified. It is intended to provide a leak detection method.

[0006]

In order to achieve the above object, the present invention provides a first opening portion on one side and a second opening portion on the other side, which are leakage inspection sections for an existing pipe. A pipe pressure detecting means having a pressure gauge and a pump means for applying a required air pressure to the detecting means are installed on the side of the second opening, and the detecting means is hermetically sealed in the second opening. The pressure inside the pipe in the leak inspection section can be read by a pressure gauge, and the flexible flexible tube is inserted inside the pipe in the state of being turned upside down from the side of the first opening. A fluid pressure is applied, and the pressurizing action advances the inverting and folded portion of the tube along the inside of the pipe to a required position to determine the inspection section, and drives the pump means to move the inside of the pipe of the inspection section. Pressurize or depressurize, and use the pressure gauge to reduce the pressure in the pipeline. Increase was monitored, by moving the position of the inversion folded portion of the tube, and identifies the occurrence position of the leakage section which occurs in the pipe path.

The tube is characterized in that it is provided with an insertion amount detecting means for detecting the insertion amount in the tube.

The fluid pressure applied in the tube is air pressure or water pressure.

[0009]

According to the leak detecting method of the present invention, the inversion tube is inserted into the pipeline from the first opening of the existing pipeline in a state of being inverted and the fluid pressure such as air or water is applied to the tube. Then, the folded portion of the tube is advanced to a required position, for example, a position 50 cm from the first opening, and stopped. The section between the folded portion of the tube and the second opening is defined as the inspection section. Next, the pump means provided on the second opening side is driven to pressurize or depressurize the inside of the inspection section. Then, the decrease or increase in the pressure in the inspection section is monitored by the in-pipe pressure detecting means equipped with a pressure gauge.

At this time, if the pressure fluctuation is confirmed in the inspection section, it is judged that there is a leakage point in the inspection section. Then, the fluid pressure is applied to the tube again, and the tube is advanced by a required amount (for example, 50 cm) to determine the inspection section. Then, similarly to the above, the pressure fluctuation in the inspection section is monitored. In the process of narrowing the inspection section in this way, the pressure fluctuation disappears when the tube blocks the leaked portion. At this point, by confirming the insertion amount of the tube into the tube by means of an insertion amount detecting means such as a scale provided on the tube, it is possible to specify that the leak location is within 50 cm of the detected value.

In addition, in order to identify the leaked portion more accurately, the folded portion of the tube is retracted and the pressure is detected again to accurately identify the leaked portion.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 indicates an existing underground pipe which is a leakage inspection target. As shown in FIG. 1, the existing pipe 1
, A pipe joint such as an elbow 1c or a socket 1d is interposed, and a leak portion h exists in the route of the existing pipe 1 due to corrosion or the like.

As a component for detecting the leaked portion h,
On the side of the second opening 1a of the existing pipe 1, a communication pipe 18 that connects the second opening 1a and the pressure detecting means 16 is connected. The pressure detecting means 16 includes a pressure gauge 17 and an orifice valve 20, and is also connected to an air pump 15 for applying air pressure. Therefore, the air pump 1
When the air is sent from 5 to the pressure detecting means 16, the air is sent to the pressure detecting means 16, the communicating pipe 18 and the existing pipe 1, and the internal pressures of the pressure detecting means 16, the communicating pipe 18 and the existing pipe 1 are increased. For example, when the pressure exceeds P1, the orifice valve 20 is opened, so that the internal pressures of the pressure detecting means 16, the communication pipe 18 and the existing pipe 1 are kept at P1.

Further, one end of the tube introducing pipe 3 is connected to the side of the first opening 1b of the existing pipe 1, and the other end of the tube introducing pipe 3 can be turned upside down with flexibility. Tube sending / storing device 1 that stores a simple tube 6
0 is connected by the connecting jig 11. Here, the tube 6 is called an inversion tube, and generally has a two-layer structure of an elastomer layer for providing a sealing property and a fiber layer for accommodating an adhesive. ing. However, in the present invention, since it is not necessary to bond the tube to the inner wall of the tube, it is possible to use a reversal tube having only the elastomer layer. Therefore, it is possible to reduce the cost of the tube, and by using only the elastic elastomer layer, it is possible to enhance the layer permeability to the inside of the conduit having many bends such as the elbow 1c.

Also, as shown in FIG.
The storage device 10 is configured so that the tube 6 can be delivered and stored, and a reel or the like is built in so that the tube 6 can be fed, stopped, and wound.
Further, an air injection control device 12 and an air pump 13 are connected to the tube delivery / storing device 10. The air injection limiting device 12 sets the air pressure fed from the air pump 13 to P2, for example, and the tube delivery / storage device 1
Send to 0. Therefore, the pressure P2 is applied to the inside of the tube 6, and the tube 6 advances into the existing pipe 1. Here, the air injection control device 12 is adjusted so that P1 <P2.

As a method of detecting a leaked portion of the existing pipe 1 in the above-described equipment structure, first, the air pump 15 is operated to keep a predetermined air pressure inside the existing pipe 1 to be leak-checked for a predetermined time. Keep calling over. At that time, if the pressure inside the pipe indicated by the pressure gauge 17 is lower than the pressure P1, it can be determined that the existing pipe 1 has a leak portion.

Then, the air pump 13 is operated to move the tube 6 into the existing pipe 1 by, for example, 50 cm. Then, the delivery of the tube delivery / storage device 10 is stopped. Then, the tube 6 is stopped while the pressure P2 is applied to the inside of the tube 6. In this state, the search section is determined to be between the inverted turnback portion of the tube 6 (position 50 cm from the first opening) and the second opening 1a.

Next, the air pump 15 is operated to apply the pressure P1 in the inspection section to perform the airtightness test. Here, from the relationship of P1 <P2, the pressure P applied in the inspection section is
The tube 6 is not pushed back by 1 and the airtight test can be properly performed within the inspection section. When the fluctuation (decrease) of the pressure gauge 17 can be confirmed, it can be determined that the leaked portion h is within the inspection section, the tube 6 is advanced further 50 cm, and the airtightness test is performed again. At this time, since the tube 6 has high layer permeability, the tube 6 can easily pass even in a curved portion such as the elbow 1c. Further, the tube 6 smoothly advances by the pressure P2, so that the inspection section can be extended to a long distance. Can be set. In addition, the pressure gauge 17
When it is not possible to confirm the pressure fluctuation, it can be determined that the tube 6 has blocked the leaked portion h, and it can be confirmed that the leaked portion h is in the 50 cm section where the tube 6 has advanced. Further, when it is desired to specify a more accurate position, the tube 6 is rewound, retracted by a required amount, and the airtight test is performed again to specify the accurate position of the leakage portion h.

As another leakage detection method, particularly when the section to be inspected extends over a long distance, first, the tube 6 is advanced to a substantially middle position of the section to be inspected, and whether the leakage portion h is in the first half position of the existing pipeline. Determine if it is in the second half position.
When the first half position is specified, the airtightness test is performed while the tube 6 is retracted by a predetermined amount (about 50 cm), and the position of the leaked portion h is specified. Further, when the latter half position is specified, as described above, the position of the leaked portion h is specified while the tube 6 is advanced.

Further, it is assumed that there are two leak parts h in the section to be inspected.
If there is one, connect one of the leak parts h to the tube 6
If it is blocked with, the rate of fluctuation will be slower than the fluctuation (decrease) in the first stage. Therefore, it is possible to specify the position of the two leaked portions h occurring in the inspection target section by specifying the point where the pressure fluctuation becomes gentle and the position where the pressure fluctuation stops.

In the above-mentioned embodiment, air pressure is used as the feeding means for the tube 6, but the present invention is not limited to this, and water or the like may be used. In this case, since the water is contained inside the tube 6, water drops will not adhere to the inner wall surface of the conduit after the tube is collected.

[0022]

According to the leak detection method of the present invention, a tube having a high layer permeability into the pipeline is advanced to the inside of the pipeline to specify the search section, so that it is sufficiently compatible with a piping system with many bends. Further, the inspection section can be set to a long distance. Therefore, unlike the conventional case, it is not necessary to create many work shafts for inspection, so that the work cost can be reduced and the work time can be significantly shortened.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a leak detection method for an existing piping system according to the present invention.

FIG. 2 is a device for delivering / accommodating an inversion tube used in the leak detection system of the present invention.

[Explanation of symbols]

1 Existing piping 1a Second opening 1b First opening 1c Elbow 1d socket 3 tube introduction tube 6 tubes 10 Tube delivery / storage device 11 Connection jig 12 Air injection control device 13 Air pump 15 Air pump 16 Pressure detection means 17 Pressure gauge 18 Communication pipe 20 Orifice valve h Leakage section

Continuation of the front page (56) Reference JP-A-5-280300 (JP, A) JP-A-7-88962 (JP, A) JP-A-60-140135 (JP, A) JP-A-9-101232 (JP , A) JP-A-47-15192 (JP, A) JP-A-51-57688 (JP, A) Actually-opened Sho 64-53941 (JP, U) Actually-opened Sho-56-133542 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01M 3/28 G01M 3/00 G01M 3/26 F17D 5/04

Claims (4)

(57) [Claims] 1. An existing pipe is provided with a first opening on one side that is a leakage inspection section and a second opening on the other side, and a pressure gauge is provided on the side of the second opening. A pipe pressure detecting means and a pump means for applying a required air pressure to the detecting means are installed, and the detecting means is airtightly connected to the second opening so that the pressure in the pipe in the leakage inspection section can be read by a pressure gauge. From the side of the first opening, the flexible tube is inserted inside the tube in a state of being turned upside down, and a fluid pressure is applied to the inside of the turning tube so that the turning action of the tube causes the turning portion to turn over. To the required position along the pipeline to determine the inspection section, drive the pump means to pressurize or depressurize the inside of the pipeline of the inspection section, and use the internal pressure detection means to detect the internal pressure of the pipeline. Monitor for decrease or increase, then invert the tube By moving the position of the then part, existing piping system leak detection method which is characterized by identifying the occurrence position of the leakage section which occurs in the pipe path. 2. The leak detection system for an existing piping system according to claim 1, wherein the tube is provided with an insertion amount detecting means capable of detecting an insertion amount in the tube. 3. The leak detection system for an existing piping system according to claim 1, wherein the fluid pressure applied in the tube is air pressure. 4. The leak detection method for an existing piping system according to claim 1, wherein the fluid pressure applied in the tube is water pressure.