JPS61139738A - Apparatus for testing leakage from joint of steel pipe - Google Patents

Abstract

PURPOSE:To reduce the time or labor of a leakage test to a large extent, by providing a replaceable seal head apparatus and an apparatus for detecting or recording the sealing pressing of a pressurized medium at the point of time when the pressure in an object to be tested reached predetermined pressure. CONSTITUTION:After the steel pipe 5b of an object 5 to be tested was inserted into the seal part 4b of an outer seal head 4, a seal head 6 is moved to the left direction by the rotation of a rotor 9a and a steel pipe 5c is inserted in the seal part 6b of the seal head 6. The force corresponding to the product of the inner area of the steel pipe and testing pressure acts on seal heads and a frame 1 supports the load thereof. Pump pressure is set by a relief valve 21 and the pressure applied to the object 5 to be tested can be known by the visual observation of a pressure gauge 23 or by the valve of a recorder 28 based on electric outputs from a pressure transducer 24 and a converter 25. When the pressure of the object to be tested reached testing pressure, a mode valve 26 is closed to seal a pressure part and the presence of the leakage at the screw joint part of the object to be tested can be judged from the change in pressure within a predetermined time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a leakage testing device for steel pipe joints, and in particular to a high-pressure testing device used for leakage testing of test objects mainly consisting of threaded joints such as steel pipes for oil wells. Regarding.

[Conventional technology]

Oil country pipes such as caning pipes, tubing pipes, and drill pipes are used in wells for oil, natural gas, etc., and they are generally connected by threaded joints.

These threaded joints are exposed to high pressure, high temperature, and corrosive environments depending on the oil well environment, so they are required to have sufficient airtightness so that they can completely withstand use even in such harsh environments.

For this purpose, depending on the type of thread, steel pipe dimensions, material, and thread tightening conditions, water pressure or gas pressure is applied as internal pressure to the steel pipe threaded joint to test for leaks and perform safety confirmation 1 quality assurance. This is widely practiced. A conventional device adopted for this purpose is shown in Figure 3. This device has blind plates 5d welded to both ends of a threaded joint made for testing, and a pressurized medium is passed through an inlet port attached to one blind plate. Inject water or gas into the threaded joint of the test object using a pressurizing device such as a pump, and after pressurizing it to a specified pressure, visually check for leakage from the threaded joint or check for bubbling (occurrence of bubbles) in the water. ). Although this method is simple, it has the following drawbacks.

(1) A blind plate is welded to each threaded joint of the test object, which takes time and effort, and is not suitable for conducting a large number of tests.

(2) Since tensile load due to internal pressure acts on the weld,
There is a risk of damage due to welding defects, leading to a major accident.

(3) Leakage detection is carried out visually, which is very dangerous, and in order to avoid this risk, observation must be done from a distance, which reduces the accuracy of detection.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a test device that significantly reduces the time and labor required for leakage testing compared to conventional methods, and enables safe and highly accurate testing.

[Means for solving problems]

The device of the invention consists of the following elements:

(A) A pressurizing device that sends a pressurized medium into the test object; (B) Depending on the pipe diameter of the test object, the outer diameter part is sealed to maintain internal pressure, or the inner diameter part is sealed to maintain internal pressure. A seal device in which the seal head is replaceable and installed within the same device.

(C) A device that applies a bending load to the test object, which can be provided as necessary; (D) Contains the pressurized medium and does not replenish the pressurized medium when the internal pressure of the test object reaches a predetermined pressure. equipment for detecting or recording pressure under conditions, and/or leak detection equipment.

[Effect]

According to the present invention, it is possible to omit the time and effort of welding a blind plate to create a test object, and it is possible to use an outer diameter seal when the test object steel pipe is small diameter, and a large diameter steel pipe. An inner diameter seal can be used, and there is no need to increase the size of the equipment when testing large diameter steel pipes.

〔Example〕

'4. JA Ming will be explained in more detail using Examples. FIG. 1 is a cross-sectional view of an embodiment of the apparatus of the present invention, showing the case of a comparatively small-diameter steel pipe test object, with an outer diameter sealing head attached, and FIG. A-A
A cross section is shown.

In Fig. 1, 1.2.3 is a frame, 11 is a pedestal, and 12 is a tank that also serves as a water receiver. One of the outer diameter seals 4 is fixed by inserting a flange 4a provided at one end thereof into a receiver 2a provided on the frame 2. The other seal pad 6 is similarly fixed to the holding plate 7. A screw 8 for moving the sole to the sole is connected to the holding plate 7. The screw 8 moves in the left-right direction by the rotation of a rotor 9a that is rotatably provided concentrically in a support member 9 fixed to the frame L, and the rotor 9a that moves the rad 6 to the seal is attached to the frame L. Rotation of the tab is transmitted from the manual handle 10b of the drive unit 10 provided at the top of the tab to the sprocket 10a, chain 9c, and sprocket 9b, and the tab is rotated.

It is also possible for the drive unit 10 to use an electric motor instead of the manual handle fob. The test object 5 is a threaded joint 5a,
It is composed of steel pipes 5b and 5c, and after first inserting the steel pipe 5b into the seal part 4b of the radial seal 4, the seal head 6 is moved to the left in the figure by the rotation of the rotor 9a, and the steel pipe 5C is inserted into the outer diameter seal. Insert into the seal portion 6b of the seal rad 6.

A longitudinal cross-sectional view of this outer diameter seal system is shown in Figure W44. It is possible to seal both ends of the test object 5 without welding blind plates.

In the outer diameter seal method, a force equivalent to the product of the inner area of the steel pipe and the test pressure acts on the seal head 4.6.

Frame 1 holds the load. In the case of a small-diameter steel pipe, the internal area is small, so the load generated is small. For example, in the case of an internal diameter of 80 mm and a test pressure of 1000 kg/ClT1', the axial load is about 50 t.

On the other hand, in the case of large-diameter steel pipes, the internal area is large, so the load generated is large6.For example, if a 13-3/8-inch steel pipe has an internal diameter of 320 mm and a test pressure of 1000 kg/cm', the axial load will be approximately aooot. , test pressure 500kg/c
ni' is also 11,400 t in the axial direction, and a large frame is required to support this, which increases the scale of the equipment and is not economical.

In addition, sending a large amount of high-pressure fluid into a large-diameter test object is undesirable from a safety standpoint, as there is a high risk of fluid leakage. Therefore, when testing large-diameter pipes, An internal diameter ring type test device that does not generate any load is optimal.

Figure 5 shows an inner diameter seal type test device.

First, the inner diameter seal pad 14 is fixed by inserting the flange L4a provided at its end into the groove 2a. The core 14b serving as an inner diameter seal head is provided with a backing 14c and a backup ring 14d for sealing the inner surface of the steel pipe. Test object threaded joint 5
is positioned as shown in FIG. The pressurized medium is press-fitted into a narrow space 15 surrounded by the core 14b, the backing 14c, the steel pipes 5b and 5c, and the threaded joint 5a, making it possible to test for leakage of the threaded portion. In this method, no axial load is generated on the test object itself, and only a force corresponding to the product of the cross-sectional area of the space 15 and the test pressure is applied to the core 14b.

For example, taking a 13-378 inch steel pipe, the distance between the inner surface of the steel pipe and the bottom of the puffing groove is 20 mm, the inner diameter is 320 mm,
When the internal pressure is 1000 kg/am', the axial tensile force generated in the core 14b is 200 t, which is reduced to approximately 200 t compared to the case of an outer diameter seal.Moreover, the force is generated only in the core 14b, and there is no force in the frame. Since no force is generated, the equipment becomes very compact, and since only a small amount of pressurized medium is required, there is little danger.

Water is often used as the pressurizing medium, but at I&K, tests are often conducted with gases that are more severe for fittings, and in this case, reducing the amount of pressurizing medium can shorten the pressurizing time. , is particularly effective in ensuring safety. Depending on the medium, pressurization methods include water pressure pumps, hydraulic-hydraulic pressure intensifiers,
Methods such as gas boosters can be used.

In addition to the above-mentioned leakage test in which only internal pressure is applied to the screw chamber under test, it is also necessary to check leakage by applying loads such as tension, compression, and bending to oil country tubular joints.

FIG. 5 shows an example equipped with a device 17 capable of applying a bending load in the case of an inner diameter seal, L6 is a lower pedestal, 16a
is a roller-like pedestal that comes into contact with the steel pipe and holds the load. There is a load device 17 at the top, a jack 17a,
It is composed of a load section 17b and a beam 17c. 17c has a structure supported by the frame l, and the jack 17a
The reaction force is received by the frame 17c and the frame l, and a bending load can be applied to the test object 5. Although FIG. 5 shows a case of three-point bending, by changing the shape of the load portion 17b, four-point bending can be achieved in which the load is applied to the steel pipes 5b and 5c instead of the threaded joint 5a. It goes without saying that a similar bending load device can also be provided for the outer diameter seal shown in FIG.
．． 6 can also be used as the lower pedestal 16.

When carrying out a leak test with a small volume of pressurized medium as in the present invention, leakage can be detected by sealing the pressurized medium after increasing the pressure to the test pressure and monitoring the pressure.

Figure 6 shows a schematic of the pressure containment system, 18
1 is a pressure pump, and 19 is a drive motor. The pump pressure is set by the relief valve 21, and the test object 5 is pressurized with the remote valve 26 in the form of a solenoid valve or an air valve open. The pressure applied to the test object 5 can be determined visually from the pressure gauge 23 or by measuring the electrical output from the pressure transducer 24 and converter 25 using the recorder 28. When the test object pressure reaches the test pressure, the transducer 24. It is possible to close the remote valve 26 in response to a signal from the converter 25 to seal the pressurized part, and determine whether there is a leak at the threaded joint of the test object from the pressure change within a predetermined time.

When the pressurized medium is water, it is relatively easy to detect a leak based on pressure changes, but it is difficult to detect a very small leak. As an example of a leakage detection device that can be suitably used in such a case, the tJTJz diagram shows an imaging system such as a camera television monitor that can detect even a minute amount of leakage.

The television camera 13 monitors the test object 5 through a gap provided between the frame 1 and the mount 11, and can view it on a monitor. At this time, if a small amount of fluorescent dye is mixed into the pressurized water and the test object 5 is irradiated with ultraviolet rays, even if there is only a slight amount of water leaking, the water will emit light, making the leak more effective and clear. can be detected.

On the other hand, if the pressurized medium is a gas, even if there is a leak, the pressure change will be small, so another detection device will be required. The simplest device is one that immerses the outside of the threaded joint of the test object in water and detects the leaking gas as bubbles. Figure 7 shows an example of an inner diameter seal.A water tank 29 is installed outside the test object 5, and is filled with water until the test object 5 is completely submerged.Gas can dance from the joint of the test object. In some cases, it floats to the surface as bubbles, making it easy to detect leaks. Of course, exactly the same device can be used in the case of external diameter seals.

One of the features of the present invention is that the seal portion is divided according to the diameter of the test object so that the outer diameter is sealed when the test object is small in diameter, and the inner diameter is sealed when the test object is large in diameter. The selection of the diameter that determines whether to seal the inner diameter or the outer diameter is arbitrary, but from the viewpoint of ease of manufacturing the seal head and compactness of the entire device, the outer diameter of 4 to 5 inches (
It is preferable to divide it by about 100 to 125 mm).

[Effects of the Invention] Since the present invention is configured as described above, it is possible to perform a leakage test on steel pipe joints in a single time efficiently and labor-savingly, without welding the test object, etc. , with high precision. Furthermore, since the outer diameter seal head and the inner diameter seal head are configured to be replaceable and attachable to the frame, the entire device can be made compact.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, and FIG. 2 is an A-
View from arrow A, Figure 3 shows a conventional steel pipe threaded joint leakage test device,
Figure 4 is a longitudinal sectional view of an embodiment that seals the outer diameter, Figure 5 is a longitudinal sectional view of an embodiment that seals the inner diameter, Figure 6 is a flow diagram of pressurized medium containment, and Figure 7 is gas pressurization. It is a longitudinal cross-sectional view of the leakage detection device in the case of. L, 2.3... Frame, 4.6... Outer diameter seal head, 5... Test object, 5a... Steel pipe threaded joint, 5
b, 5c...Steel pipe, 7...Holding plate, 8...Head moving screw, 9...Supporting member, lO...Drive unit. DESCRIPTION OF SYMBOLS 11... Frame, 12... Tank, 13... Television camera, 14... Inner diameter seal head, 15... Space, 16... Lower pedestal, 17... Bending load device, 18
...Pump, 19...Motor, 21...Relief valve.

Claims (1)

[Scope of Claims] 1. A pressurizing device that sends a pressurized medium into a test object, an exchangeable seal head device that seals the outer diameter or inner diameter near both ends of the test object depending on the pipe diameter of the test object, and a test object. 1. A steel pipe joint leakage testing device comprising a device for detecting or recording pressure by sealing a pressurized medium when the pressure inside the test body reaches a predetermined pressure, and/or a leakage detection device. 2. A steel pipe joint leakage testing device according to claim 1, comprising a device that applies a bending load to the test object.