JPH0792049A - Leak detecting device for pipe fitting - Google Patents

Abstract

PURPOSE:To protect a detector from a condensing gas such as oil vapor or steam, and keep the leak detection highly sensitive by successively arranging a constant temperature bath, an air filter mechanism, and a paper filter mechanism in a transporting pipe toward the detector. CONSTITUTION:A mixed gas of helium and nitrogen is supplied into a pipe 1 from the feed hole 3a of a block 3 arranged on a pipe 1 both ends. An oil vessel 4 alternately feeds high temperature and low temperature hot medium oils around a tube fitting 2 to impart the heat cycle of the pipe 1. A vessel 5 collects the leak gas from the fitting 2 and transfers it to a detector 8 by a pure nitrogen blown through a piping 7 by a transfer pipe 6. A constant temperature bath 9 lowers the temperature of the gas in the transfer pipe 6 to condense it, and the oil and water contents in the gas are removed through a valve 6a. The remaining oil and water contents are again collected by an air filter mechanism 10, and the oil vapor and steam passing it are removed by a paper filter mechanism 11. The detector 8 judges the presence or absence of the leak gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak detecting apparatus suitable for investigating the gas seal resistance of a joint portion of a pipe used for mining oil or gas.

[0002]

2. Description of the Related Art The depth of an oil well reaches several thousand meters, and in recent years it has reached about 10,000 meters. An enormous number of oil well pipes are vertically inserted into such an oil well, all of which are connected by pipe joints.

Such pipe joints include various types such as axial tensile force due to the weight of the pipe and the pipe joint itself, pressure from the outer peripheral surface of the pipe (ground pressure), pressing force on the inner peripheral surface by the internal fluid, etc. The harsh power of

Needless to say, these forces become more severe as the depth of the oil well increases, and in a pipe joint that can be used under such severe conditions, a large tensile load is applied. It is required to have a reliable sealing property while being capable of withstanding.

Many proposals have hitherto been made as joints that meet the above-mentioned requirements. As a typical example of them, the ends of the pipes are screwed to connect the pipes to each other. A coupling type is known (Fig. 3
reference).

For a pipe connected using such a pipe joint, it is indispensable to investigate the gas sealability at the joint portion before the pipe is installed. Gas leak resistance test is conducted according to the procedure.

A block for exerting a tensile force along the axial direction is attached to each end of a pipe (test body) connected by a pipe joint, and nitrogen gas containing a specified amount of helium gas is used as the internal pressure of the test body. While loading, a heat cycle is applied to the test body by alternately sending hot and cold heat transfer oil around the joint portion of the pipe.

Then, by using a leak detection device composed of a container for collecting leaked gas in the joint portion, a gas transfer pipe and a detector, it is investigated whether or not the gas leaks from the joint portion, or the amount of leaked gas. (Whether gas is leaking from the joint, or the amount of gas leaked, the carrier gas (pure nitrogen gas) was made to flow through the transfer pipe at a constant speed, and the gas carried to the detector It is judged by detecting the amount of helium or its amount.

[0009]

As described above, the gas seal resistance of a pipe joint is often investigated by simulating the actual condition of an oil well (performed under a thermal cycle). The heat transfer oil used for the purpose of applying a heat cycle to the test piece, or grease oil called a compound used for tightening the pipe joint part, becomes liquid or mist due to the temperature increase of the heat cycle. When the leaked gas enters the container for collecting the leaked gas, oil or water is condensed in the leak detection analysis gas, which lowers the sensitivity of the leak detection device or causes a malfunction of the device.

Regarding this point, a paper filter is conventionally provided in the leak gas transfer path. However, although such measures prevent the effect of oil to some extent, the above problem is completely eliminated. It has not been resolved.

An object of the present invention is to provide a leak detecting device for a pipe joint, which can protect from a condensable gas such as oil vapor and water vapor and can maintain high leak detecting sensitivity.

[0012]

According to the present invention, there is provided a container for collecting leak gas from a pipe joint, a transfer pipe for transferring the leak gas collected in the container, and whether the leak gas is transferred to the transfer pipe. A device for investigating gas leak resistance, which comprises a detector for judging whether or not a thermostatic chamber for lowering the temperature of leak gas, an air filter mechanism, and a paper filter mechanism are sequentially installed in the transfer pipe toward the detector. This is a leak detecting device for a pipe joint.

[0013]

[Function] Regarding the leak detection device used when investigating the gas sealability of pipe fittings used in the mining of oil and gas, etc., a constant temperature bath is provided inside the transfer pipe for the leak detection analysis gas to reach the detector. Oil droplets or oil vapor contained in the gas by lowering the temperature of the gas by the refrigerant of
Condensable gas of water vapor can be reduced, and the detection sensitivity of the device can be maintained at a high level.

Further, by providing a paper filter mechanism which can be easily replaced with an air filter mechanism so as to block the transfer pipe in the transfer pipe following the constant temperature tank, the oil contained in the gas for the leak detection analysis gas. It is possible to further reduce the condensable gas such as drops or oil vapor and water vapor, and maintain the detection sensitivity of the device at a high level.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a detector according to the present invention attached to a test body. In the figure, 1 is a pipe used for mining oil or gas, and 2 is a pipe joint for connecting the pipe 1. Therefore, the pipe joint 2 and the pipe 1 constitute a test body.

Numeral 3 is a block which is arranged at each end of the pipe 1 and exerts a tensile force along the axial direction. At least one of the blocks 3 is filled with a mixed gas of helium and nitrogen in the pipe 1. A supply hole 3a for supplying is formed.

Reference numeral 4 denotes an oil vessel that surrounds the pipe 1 and alternately sends high-temperature and low-temperature heat transfer oil around the joint to give a heat cycle to the pipe 1. Reference numeral 5 denotes a container for collecting leak gas from the pipe joint 2. , 6 is a valve 6 for draining the drain
Pure nitrogen gas (carrier gas) having a and having the leak gas collected in the container 5 blown through the pipe 7.
A transfer pipe (made of copper or the like) for transferring at 8; a detector connected to the transfer pipe 6 and determining whether or not a leak gas exists; 9 a constant temperature bath for lowering the temperature of the gas in the transfer pipe 6; The air filter mechanism 11 is a paper filter mechanism that can be easily replaced. The air filter mechanism 11, the transfer pipe 6, the detector 8, the constant temperature bath 9, the air filter mechanism 10, and the paper filter mechanism 11 serve as a pipe joint mechanism. Configure a leak detection device.

The constant temperature bath 9 is intended to remove oil and water contained in the gas by lowering and condensing the temperature of the leak detecting analysis gas in the transfer pipe 6, and a refrigerant in the bath. It is recommended that about 10 liters of ethanol and a handy cooler be constantly set to about -20 ° C. The refrigerant body can be changed to a type of medium according to the type of heat transfer oil and is not particularly limited. During operation of the detection device, the oil and water condensed can be removed by opening the valve 6a in the vicinity of the outlet side of the constant temperature bath 9.

The air filter mechanism 10 is installed for the purpose of collecting again the oil and water that could not be removed in the constant temperature bath 9. Here, too, the oil and water are removed by opening the valve 6a. be able to. The capacity of the air filter may be about 500 cc, but if it becomes too large, it will take time for the leaked gas to flow to the leak detection device, so it is optimal to set it to about 100 cc. Particularly, it is preferable to have a capacity of about 100 cc because it can have a function as an oil reservoir when the heat transfer oil suddenly enters the transfer pipe 6. If the mesh size of the filter is 5 μm, it is insufficient to reduce the oil vapor. On the other hand, if it is smaller than 0.5 μm, clogging is likely to occur and the leak response becomes poor. For this reason, the size of the filter mesh is preferably about 2 μm.

Regarding the paper filter mechanism 11, a paper filter having a mesh size of about 1 μm is attached after the air filter mechanism to remove oil vapor and water vapor that have passed through the air filter 10.

80 mm length by API standard, outer diameter 88.9 mm, wall thickness
When a thermal cycle was applied to a 6.45 mm oil country tubular good under the following conditions and a gas leak resistance test of the joint part was performed, the results shown in FIG. 2 were obtained.

Thermal Cycle Conditions The thermal cycle uses 30 high temperature (280 ° C) and low temperature (66 ° C) oils.
Send in alternating rotations, one high temperature and one low temperature for a total of 1 hour
As a cycle, a 25-cycle test was performed 8 times (200 cycles).

FIG. 2 above shows the number of times the leak detection device has been adjusted to increase the detection sensitivity because the leak detection sensitivity has decreased due to the condensable gas of oil droplets or oil vapor or water vapor. is there. As is clear from the figure, in the device according to the present invention, no adjustment was required to enhance the detection sensitivity, whereas in the comparative example using the ordinary device, 0.12 adjustments were required per cycle. It was confirmed that

[0024]

According to the present invention, not only the leak detection device can be protected from the condensable gas such as water vapor and oil vapor to maintain the detection sensitivity of the device at a high level, but also the adjustment cost for it is significantly increased. Reduction has become possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a leak detection device according to the present invention.

FIG. 2 is a diagram showing a result of checking the number of adjustments of the detection sensitivity of the leak detection device.

FIG. 3 is an end view of a main part of a pipe joint.

[Explanation of symbols]

 1 Pipe 2 Pipe Joint 3 Block 4 Oil Vessel 5 Container 6 Transfer Pipe 7 Piping 8 Detector 9 Constant Temperature Chamber 10 Air Filter Mechanism 11 Paper Filter Mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichi Suzuki, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Technical Research Division, Kawasaki Steel Co., Ltd. (72) Masataka Sonoda 1-1, Kawasaki-cho, Handa-shi, Aichi Kawasaki Steel Co., Ltd.Chita Works

Claims (1)

[Claims] 1. A container for collecting leak gas from a pipe joint, a transfer pipe for transferring the leak gas collected in the container, and a detector connected to the transfer pipe for judging whether or not the leak gas is transferred. A device for investigating gas leak resistance, comprising a pipe joint characterized in that a constant temperature bath for lowering the temperature of leak gas, an air filter mechanism, and a paper filter mechanism are sequentially arranged in the transfer pipe toward the detector. Leak detector.