JPS6159438B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for skin-to-skin joining of joint ends of pipes and a test method thereof, which eliminates the conventional complicated work and automatically determines a suitable joint end. The aim is to create a method for completing joining and testing in a short period of time, by which skin alignment can be easily performed, and the quality and strength of the joint can be tested at the same time after welding is completed.

Traditionally, pipes have been joined together using various materials, not just steel pipes.Joining involves a complex process of skin-aligning the pipes, but the joints require testing for strength and leakage. Therefore, in factories and piping construction sites, it is customary to join a fixed length of pipe to a certain length, close both ends with blind covers, confine pressurized fluid inside, and perform leakage and strength tests. be.

This blind lid method requires a large amount of pressurized fluid, but with such a large volume, even a small leak will cause a small change in pressure.
Since it will be left for a long time (for example, over a day and night), it will be necessary to correct the pressure due to temperature changes during that time. However, although this method can be carried out in limited places such as certain factories, there are problems in strength testing and leakage testing by introducing fluid into underground submarine piping. That is, even if it were possible to fill the entire pipe with pressurized fluid, it would require a large amount of fluid, many man-hours, and time, and in the event of a leak, it would be impossible to determine the location of the leak. In order to confirm, for example, in the case of buried piping, the soil that has been backfilled must be dug again and all joints checked with soapy water, etc., which can result in a large loss of labor and time. Become. In addition, in the case of buried piping on site, it is especially necessary to shorten the time of traffic interruption as much as possible.
It is important to perform on-site leak tests and pressure tests in as short a time as possible.

Accordingly, there is a keenly felt need for improvements in the operations associated with joining pipes. First, let us refer to the conventional state.

The state of the conventional process of aligning the joint ends of two pipes to be joined will be described.

For example, in the case of steel pipes, the cross section of the steel pipe is not necessarily a perfect circle, but rather an ellipse, and tolerances are allowed for the pipe diameter, so it is common for each pipe to have a different inner diameter.

The skin alignment mentioned here includes two operations: centering, which aligns the axes of the two tubes, and, if the tubes are somewhat oval, aligning the long axes or short axes of the two tubes.

Conventionally, in order to align the skin, it was necessary to measure the diameters of the two tubes in several places to find the long axis direction, turn the tubes to be joined so that the long axis directions match, and then measure the diameters of the tubes. First, the two tubes are aligned so that their central axes are on the same line. Centering will be explained based on FIGS. 1 and 2.

FIG. 1 is a front view showing the alignment state after longitudinal alignment, and FIG. 2 is a side view.

In the figure, reference numeral 1 denotes a U-shaped metal fitting. First, one end of the U-shaped metal fitting 1 is fixed by welding 2 to a pipe a having a large diameter parallel to the axial direction at equal intervals in the radial direction.
As shown in FIG. 2, this U-shaped metal fitting 1 is provided at three or more locations on the outer periphery. Next, align the long axis direction and insert the tube b inside the U-shaped fitting 1,
After driving the wedge 4 between each U-shaped fitting 1 and the tube b and performing centering, the gap 3 between the wedge 4 and the tube b is welded, and both ends of the tubes a and b are connected to the U-shaped fitting 1. to fix and position it, and then weld the butt periphery. After welding, the welded portion of the U-shaped metal fitting 1 is cut off, and any scratches left on the outer circumferential surface are repaired. Furthermore, this conventional method uses the outer surface as a reference, and there is a high possibility that a step will be formed on the inner surface.

As mentioned above, skin-to-skin joining has conventionally been performed through such complicated operations.

Therefore, the inventors aimed to improve such conventional complicated work, and found that there is no need for centering adjustment of the conventional U-shaped metal fitting 1 or wedge 4, and that the long axis of the elliptical shape is This research explores a method that can eliminate the need for dimension measurements to match the dimensions. That is,
We devised a fitting and testing device for the joints, and used this device to align one side of the pipes to be joined with the center axis of the device, and at the same time, rounded the pipes and then tested the other pipe. After aligning the pipe by aligning it with the same central axis as the device and making it a perfect circle, the joint is welded and the welded part can be subjected to pressure tests as is.

Next, the principle of the mechanism for aligning the joined pipes of the present invention will be explained with reference to a sectional view of FIG. 3 showing the aligned state.

In the figure, CTE is a skin matching/testing device, and the left half is the same as the right side and has been omitted. In other words, the center line between the left and right sides of the device
The left and right sides of the ME are configured in the same form,
This device consists of a circular inner base 5A and a circular outer base 5B at both ends thereof, and 6 is a hollow part, but it does not necessarily have to be a hollow part. In this device, on the outer periphery of a circular inner base 5A, a test space TS for leakage tests and strength tests is formed near the center with both side walls 7 having a U-shaped cross section. Wedge mechanisms WM for skin alignment are provided on both outer sides, and pressurized sealing mechanisms SM are formed on the outer periphery of the circular outer base body 5B at both ends thereof. The outer base body 5B is hermetically fixed to both ends of the inner rule base body 5A using fixing devices such as bolts 14.

The above wedge mechanism WM is the test space part
It is set in the space between the side wall 7 of the TS and the inner wall 9 of the pressurized sealing mechanism SM. Pressure seal mechanism
In the SM, an annular seal space portion 10 having a rectangular cross section is formed by an outer wall 8 and an inner wall 9 on the outer periphery of the outer base body 5B. The movable seal ring 11 shown in FIG. 5 is inserted into the seal space portion 10, as shown in the enlarged sectional view of FIG.

As shown in the enlarged sectional views of FIGS. 5A and 5B, the movable seal ring 11 has seal lips 11a for self-sealing protruding from both sides on the inner diameter side of the ring, and the outer circumferential surface has a skin-matching surface. This is a sealing surface 11b that seals between the inner circumferential surface of the connecting pipe and an uneven pattern may be formed on the surface as necessary. As shown in FIG. 5-A, this movable seal ring 11 is molded only from a rubber-like elastic body such as rubber or plastic, and as shown in FIG. 5-B, a reinforcing cord 12 is molded in the width direction. Toward this end, there are cases where individual cords are buried in parallel over the entire circumference. This reinforcing movable seal ring 11 can freely expand in the outer diameter direction, but its strength in the lateral direction (axial direction) is increased, and it can strongly support deformation in the lateral direction. This is preferable because a stronger sealing function can be obtained.

Figure 4 shows an enlarged sectional view of the pressurized seal mechanism SM in Figure 3, and shows the seal space portion 1.
When the movable seal ring 11 is inserted into the movable seal ring 11, the seal lip 11a is pushed into the outer wall 8 and the inner wall 9, and contact pressure is generated between the two walls. When pressurized fluid is introduced from 13, the movable seal ring 11 comes into contact with the inner surfaces of the connecting tubes to be sealed and exhibits sealing properties, and the seal lip 11a is strongly pressed against both wall surfaces by the pressure of the pressurized fluid itself. , which exhibits even stronger self-sealing.
Furthermore, since the sealing function can be freely changed by applying pressure, it is possible to not only respond to changes in the state of the contact surface, but also to obtain reliable sealing performance.

Next, we will refer to the wedge mechanism WM of the above device.

In the figure, 15 is a ring-shaped wedge that slides on the inner base 5A, and 16 is a cylinder having a ring-shaped space, which functions to push out the ring-shaped wedge 15.
is always pulled by the spring 17.
Reference numeral 18 denotes skin matching wedges provided at several locations around the circumference, which are connected to the ring-shaped wedge 15 through grooves 19 or the like. Of course, the greater the number of wedges 18 for skin matching, the higher the accuracy of the roundness correction of the tube. 2
0 is an O-ring, and the space of the wedge mechanism WM is formed by the pressurized seal mechanism SM and the O-ring 20.
It is kept airtight from the outside during leakage and strength tests.

Next, an exemplary skin-to-edge joining method and testing method for the joining end portions of the pipe body Pa and the connecting pipe Pb will be described.

Insert approximately 1/2 of the above skin matching/testing device CTE, that is, the right half of the center line ME into the tube Pa,
When pressurized fluid is introduced into the cylinder 16, the ring-shaped wedge 15 is pushed out toward the center, and the skin-matching wedges 18 provided at several locations move in the radial direction and are pressed against the inner surface of the tubular body Pa, resulting in skin-matching. It operates so that the center line EC, which is the axis of the test device CTE, and the center line PaC of the tube Pa are on the same line, and the cross-sectional elliptical distortion of the tube Pa is corrected so that it becomes close to a perfect circle. It becomes firmly fixed. FIG. 3 is a sectional view showing this state.

Next, a joining pipe Pb to be joined to the pipe body Pa is inserted into the portion of the pipe body Pa that projects outside, that is, the left side of the center line ME of the device. In this state, as shown in the figure, the center line PbC of the connecting pipe Pb is
The center lines EC and PaC of ETC and tube body Pa are different from each other. In this state, next, the cylinder 16 of the skin matching wedge mechanism WM on the left half of the center line ME of the device
When pressurized fluid is introduced into the pipe body Pa, the center line PbC, which is the axis of the connecting pipe Pb, is lifted, and the center line EC of the device ETC and the center line of the pipe body Pa are lifted.
At the same time, the distortion is corrected so that it is on the same line as PaC, and the tubes are completely aligned, and the tubes are held firmly in a fixed state.

Next, this fixed state of the skin-matching continuous portion JP is welded to perform skin-matching joining of the joining end portions.
When welding is completed, pressurized fluid is introduced into the seal spaces 10 on both sides of the pressurized seal mechanism SM, and not only the test space TS but also the entire device becomes sealed. In this sealed state, the test pressurized fluid inlet 2 of the test space section TS
When a pressurized fluid is introduced into 1, a leakage test and a strength test of the welded portion are continuously performed on the welded body as it is.

As mentioned above, this method can be used at the pipe welding site,
It is a method that allows continuous and consistent alignment of the joint ends of pipe bodies to be joined, welding, and testing at a buried site, etc. In particular, in the case of buried pipes, it can be performed consistently at the buried site. If there are no abnormalities as a result of the test, it can be backfilled immediately, and has the great advantage of reducing traffic interruptions in a short time. In addition, there is no need to go through the trouble of removing and repairing the welded parts of the alignment fittings.
In addition, it has remarkable features such as the ability to immediately check for leakage and the strength of the welded part through local testing at the same time as welding, without the need to separately test the entire long pipe. A particularly significant effect is that everything can be completed in a short period of time.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the mutual alignment of conventional jointed pipes, Fig. 2 is a side view of the welded part of the U-shaped metal fitting in Fig. 1, and Fig. 3 is a side view of the welded part of the U-shaped fitting shown in Fig. 1. FIG. 4 is an enlarged sectional view of the sealing mechanism of the skin matching/testing device, and FIGS. 5A and 5B are enlarged sectional views of the movable seal ring. 5A...Inner base, 5B...Outer base, TS...Test space section, 7...Side wall (of the test base section), SM...Pressure type seal mechanism, 8...Outer wall, 9...
Inner wall, 10... Seal space portion, 11... Movable seal ring, WA... Wedge mechanism for skin alignment, 15...
Ring-shaped wedge, 18... Wedge for skin matching, 19...
Dovetail, ME...Central line (of skin matching and testing equipment), EC...Center line of skin matching and testing equipment, PaC...Center line of pipe, PbC...Center line of connecting pipe, (Pb), JP
...Connection part.

Claims (1)

[Claims] 1. An annular test space with walls on both sides is formed near the center on the circular inner base, and a pressurized sealing mechanism consisting of an annular seal space with a rectangular cross section and a movable seal is formed on the outer base at both ends. A skin-matching wedge connected by a groove on a ring-shaped wedge is provided at two places on the left and right between the inner wall of the sealing mechanism at both ends and the side wall of the sealing space part, and a skin-matching wedge connected by a groove is placed on the ring-shaped wedge so that the ring-shaped wedge slides. Insert one side of the left and right sides of the center line of the skin matching/testing device, which is equipped with a wedge mechanism for skin matching that can move up and down, into one side of the connecting pipe body, and insert the ring-shaped wedge of the insertion part. actuating in the central direction to expand the skin matching wedge in the radial direction to firmly fix the device;
Next, insert the other side of the skin matching/testing device into the other side of the pipe body to be connected, and in the same manner as above, move the ring-shaped wedge toward the center to firmly fix the pipe body and the connecting pipe. The mutual center line and the center line of the skin matching/testing device are made to match, and rounding correction is performed, and this fixed joint is welded. After welding, the seal space of the pressurized seal mechanism on both sides is A method for skin-to-skin joining and testing of joint ends, characterized by introducing pressurized fluid into the test space to create a sealed state, and testing the leakage and strength of the weld by introducing pressurized fluid into the test space.