JPH02122233A - Inspection instrument for leak of welded flexible gas pipe - Google Patents

Abstract

PURPOSE:To substantially improve the detection sensitivity of a gas detector so that a gas leak can be detected surely by allowing a gas pipe in which gas for becoming an index is enclosed by pressure to pass through the inside of an airtight container. CONSTITUTION:A gas pipe 13 is run so as to pass through the inside of an enclosed container 10. In such a case, when a defect such as a welding failure and a pin hole, etc. exists in the gas pipe 13 and a gas leak is generated, its defective part enters into the container 10, gas leaks out and diffused in the inside of the container 10, its gas is detected by a gas detector 15, or gas blown out of the gas pipe 13 is detected directly by the detector 15, and for instance, an electric signal is outputted. On the other hand, unless a defect for generating a gas leak exists in the gas pipe 13, the detector 15 outputs no signal. Accordingly, by the signal to be detected 15, a gas leak can be known, and a gas leak part can be detected easily.

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a device for inspecting leaks in gas pipes for transporting or supplying gas, and in particular leaks caused by poor welding or pinholes in the material of welded flexible gas pipes. This invention relates to a device for detecting gas leaks.

2. Description of the Related Art An example of a conventionally used device of this type is schematically shown in FIG. In FIG. 3, symbols A and B are welded flexible gas pipes to be inspected, each having valves 1 and 2.
．． A gas cylinder (not shown) is connected via 3, and each gas pipe A.

A differential pressure gauge 4 is arranged between the gas pipes A and B, and the differential pressure gauge 4 is connected to each gas pipe A and B via valves 5 and 6. Roughly speaking, each gas pipe A, B has a gas pressure gauge 7 that indicates its internal pressure.
8 is taken (-1 is taken.

Gas leak detection using the above device is performed as follows. First, seal both ends of each gas pipe A and B,
Then, with the differential pressure gauge 4 attached and valves 5 and 6 closed, valves 1 and 2.3 are opened to supply gas from the gas cylinder, and the inside of each gas pipe A and B is pressurized (for example, 5 K).
Fill with gas at a rate of about 100 g/ci). When the indications of the gas pressure gauges 7 and 8 are both stable, open the valve 5.6 to which the differential pressure gauge 4 is attached, put the differential pressure gauge 4 in communication with each gas pipe △ and B, and connect one gas pipe A. pressure on the side and gas pipe B on the other side
If the difference between the two pressures is equal to or greater than a predetermined value, it is determined that there is a leak in the gas pipe with the lower pressure, and if the pressure difference is equal to or less than the predetermined value, it is determined that there is no gas leak.

Problems to be Solved by the Invention However, the two gas pipes A and B, which are the objects to be inspected, are not necessarily exactly the same in dimensions such as length and diameter, or in structure, and may also have different humidity levels. Therefore, in the above-mentioned conventional device, a pressure difference may occur between each gas pipe A and B due to such a difference in conditions, so even if a pressure difference occurs between each gas pipe A and B, it is There are problems in that it is difficult to unambiguously determine whether the gas leak is caused by a gas leak, and it is difficult and time-consuming to judge whether the gas leak is good or bad. Furthermore, in the conventional apparatus described above, even if it is known that a gas leak has occurred due to a large differential pressure, the gas leak test is generally conducted using the long gas pipe A.

Since the test was carried out for B, it was not immediately possible to know where the gas leak was occurring, and there were problems such as difficulty in finding the gas leak location.

This invention (which was made in order to solve the above-mentioned problems) aims to provide a device that can easily and reliably determine the presence or absence of a gas leak and, if so, the location of the gas leak. It is something.

Means for Solving the Problems In order to achieve the above object, the present invention runs a gas pipe as an object to be inspected through an airtight container, and detects a gas detector inside the airtight container. The device is configured to detect the indicator gas using the following method. More specifically, the device of the present invention allows a welded flexible gas pipe filled with an index gas under pressure to pass through and travel in an airtight state at a predetermined location in the sealed container. The device is characterized in that a detector is arranged to output a signal in response to the gas.

In the present invention, a rotating body may be provided inside the airtight container to rotate the gas pipe by winding the middle part of the gas pipe in a spiral manner.

Function: In the device of the present invention, the gas pipe is run so as to penetrate the inside of the closed container in a state in which a gas to be used as an index is pressurized and sealed therein. Therefore, if the gas pipe has defects such as poor welding or pinholes that cause gas leakage,
Gas blows out from there, and if the defective part reaches the inside of the sealed container, the gas concentration inside the sealed container will increase.
As a result, by constantly detecting the gas concentration inside the sealed container using the gas detector, it is possible to know the gas leak and its cause.

Example Next, embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention, in which a closed container 10 is a container with a cylindrical or rectangular cross section, and inlets 11 are provided at three locations facing each other or at three appropriate locations. A delivery port 12 is formed. These inlet port 11 and outlet port 12 are for allowing the welded flexible gas pipe 13 to be inspected for gas leakage to pass through so that it can run, and the inner circumference of the inlet port 11 and the outlet port A sealing material 14 for maintaining airtightness with the gas pipe 13 is provided on each of the inner peripheral portions of the gas pipes 12 and 12 . Furthermore, a gas detector 15 is arranged inside the closed container 10 to detect a gas used as an index.

Before performing a gas leak test, a suitable gas as an indicator to be distinguished from air is sealed inside the gas pipe 13 under pressure, and one end of the gas pipe 13 is sealed from the introduction port 11. Insert it into the container 10 and pull it out from the delivery port 12.

The interior of the sealed container 10 may be configured to have a meandering gas pipe 13 by providing a plurality of guide rollers, etc., to actively leak gas from defective locations, and to use it as an indicator. In order to increase the detection accuracy by relatively increasing the gas concentration, the pressure inside the closed container 10 may be reduced.

In the above-described state, the gas pipe 13 is run through the inside of the closed container 10. If there is a defect such as a welding defect or a pinhole in the gas pipe 13, and gas leaks from the defective point, the defective point will enter the inside of the sealed container 10, causing gas to leak into the sealed container 10. The gas that leaks out and diffuses is detected by the gas detector 15, or the gas ejected from the gas pipe 13 is directly detected by the gas detector 15 and outputs, for example, an electrical signal. On the contrary, gas pipe 1
If there is no defect that causes gas leakage in 3, even if the entire gas pipe 13 passes completely through the hermetic container 10, there will be no gas inside the hermetic container 10.
The gas detector 15 never outputs a signal. Therefore, gas leakage can be detected by the signal output from the gas detector 15, and the gas detector 1 of the gas pipe 13
5 outputs the signal, it means that there is a defective point where gas leaks in the part located inside the closed container 10, so that the gas leak point can be easily discovered.

Note that the gas pipe 13 may run continuously, or may run intermittently, with the length from the inlet 11 of the closed container 10 to the outlet 12 being one pitch. .

Further, a plurality of gas detectors 15 may be arranged, and the inside of the closed container 10 may be divided into a plurality of compartments, and a gas detector 15 may be arranged in each compartment.

FIG. 2 shows another embodiment of this defense, which is an example constructed to improve space efficiency.

That is, a pair of capstans 16.17 around which the welded flexible gas pipes 13 are wound spirally are respectively rotatable and arranged parallel to each other. is housed in. Each closed container 18.19 has a capstan 1
6.1. ．． An inlet 20, 21 and an outlet 22, 23 are formed which face approximately in the tangential direction of FIG. The introduction ports 21 face each other. These inlet ports 20.21 and outlet ports 22
．． 23 is a hole for inserting the gas pipe 13,
A sealing material 24 for maintaining airtightness with the gas pipe 13 is provided on the inner peripheral side of each. Gas detectors 25 and 26 are arranged inside each closed container 18 and 19, respectively.

In addition, in the apparatus shown in FIG. 2, each closed container 18.1
9 may be depressurized.

A gas leak test using the apparatus shown in FIG.
．． 17, as shown in FIG. 2, and the gas pipe 13 is run in this state. Therefore, if there is a gas leak defect in the gas pipe 13, the defect will first enter the inside of the closed container 18 on the left side in FIG.
8, the gas concentration inside the gas pipe 13 becomes high, or
The gas ejected from the gas detector 25 is directly sprayed onto the gas detector 25, and as a result, the gas detector 25 outputs a signal in response to the gas. Note that if the gas pipe 13 is wrapped around the cab stan 16 multiple times, the defective location will pass through the gas detector 25 multiple times, so each time the gas will pass through the gas detector 25.
If the gas is directly blown onto the gas, the output signal of the gas detector 25 will increase each time. Therefore gas detector 2
5 outputs a signal, it means that a gas leakage defect exists in the portion located inside the closed container 18, and the defective location can be easily discovered. Further, the gas pipe 13 is sent out from the closed container 18 on the left side of FIG. 2 and then sent into the closed container 19 on the right side of FIG. Inside this airtight container 19, the airtight container 1 on the left side of FIG.
8 as well as the capstan 17 and gas detector 2
6 is placed, gas leak detection is performed again here, and the location of the gas leak can therefore be confirmed. If the configuration shown in FIG. 2 is used, each airtight container 1
Since the length of the gas pipe 13 located inside the 8.19 is increased, space efficiency is improved.

In the case of the configuration shown in FIG. 2, in order to prevent excessive tension from being applied to the gas pipe 13, the left and right capstans 16 and 17 are connected by a transmission means 30 to which a belt or chain is wound. both capstans 16.17
It is preferable to configure it so that it rotates at a constant speed. Further, in the configuration shown in FIG. 2, the gas pipe 13 is once exposed to the outside between the left and right sealed containers 16 and 17, but the delivery port 22 of one sealed container 18 and the inlet port of the other sealed container 19 A case may be provided between the gas pipe 13 and the gas pipe 21 to airtightly surround the gas pipe 13, and a gas detector may be used to detect gas leakage in that portion as well. Further, a plurality of gas detectors may be arranged in each closed container 18, 19 as necessary.

Effects of the Invention As is clear from the above description, the device of the present invention detects gas within an airtight container by passing a gas pipe filled with a pressurized index gas into the container. Because of this configuration, the substantial detection sensitivity of the gas detector is improved, and gas leaks can be reliably detected.

Further, since the gas leak location is located inside the closed container when the gas detector is activated, the gas leak location can be easily discovered. In particular, if the gas pipe is wound around a rotating body such as a capstan in a closed container, the length of the part of the gas pipe that is housed in a narrow space becomes long, so it is necessary to miniaturize the device. Space efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention, FIG. 2 is a schematic sectional view showing another example, and FIG. 3 is a schematic view showing an example of a conventional device. 10.18.19...Airtight container, 11.20°21
...Inlet port, 12,22.23...Outlet port, 1
3...Gas pipe, 14.24...Sealing material, 15
゜25.26...Gas detector.

Claims (2)

[Claims] (1) A welded flexible gas pipe filled with a pressurized gas as an index is passed through in an airtight state, and a signal is output to a predetermined location of the sealed container in response to the gas inside the sealed container. A leak inspection device for a welded flexible gas pipe, characterized by having a detector arranged therein. (2) The welding flexible gas according to claim 1, characterized in that a rotating body is provided inside the airtight container to cause the gas pipe to run by winding the gas pipe in a spiral and rotating the rotating body. Leakage inspection device for pipes.