JPH0216859B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining pipes by aligning the ends of the joints, and more specifically, by omitting the conventional complicated work and automatically aligning the ends of the joints in a suitable manner. It is easy to make, makes use of the space available for welding, and can test the quality and strength of the joint immediately after welding, allowing you to confirm the completion of welding, shortening the process and ensuring a perfect joint. This relates to a joining method. Traditionally, pipes have been joined together using various materials, not just steel pipes, but joining involves complex surface alignment of 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, then close both ends with blind lids, etc., trap pressurized fluid inside, and perform leakage and strength tests. be. It goes without saying that this blind lid method requires a large amount of pressurized fluid, but when the volume is large, even a small leak will cause a small change in pressure. ), and pressure correction due to temperature changes during this period is also required. However, although this method can be implemented in limited places such as certain factories, underground
For submarine piping, there are problems with strength testing and leakage testing by introducing fluid. 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 up again and all joints checked with soapy water, etc., which results in a large loss of labor and time. Become. In addition, in the case of buried piping on site,
In particular, it is necessary to shorten the time during which traffic is shut down as much as possible, and it is essential that on-site leak tests and pressure tests be carried out 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. Conventional alignment 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 welded 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, aligning the longitudinal axis direction, insert the tube b inside the U-shaped metal fitting 1, drive the wedge 4 between each U-shaped metal fitting 1 and the tube b, and perform centering. The gap 3 between the wedge 4 and the tube b is welded, both the tubes a and b are fixed and positioned with the U-shaped metal fitting 1, and the butted peripheral edges are welded. 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 created a method that eliminates the need for centering adjustment using the conventional U-shaped metal fitting 1 and the wedge 4, and also allows the long axis of the ellipse to be adjusted. This research explores a method that can eliminate the need for dimension measurements for alignment. That is,
We devised a device for skin-aligning joints, and used this device to align one side of the pipes to be joined with the center axis of the device by applying pressure fluid, and at the same time to ensure that the strain in the pipes was also true. Then, by pressurizing the other joining pipe with pressure fluid in the same manner as described above, it is made to have the same center axis as the device, and at the same time, the strain in the pipe is also made into a perfect circle, and the pipes are brought into line with each other. is to be carried out. After this skin matching is completed, the joint is welded and the welded part is then subjected to a pressure test. The basic mechanism will be explained. First, we will discuss the technical background regarding the centering action of a particularly tough rubber-like elastic body made of an elastic polymer material. Figure 3 shows a normal rubber tube, Figure 3-A
Figure 3-B is a cross section showing the state before expansion, and Figure 3-B is a cross section showing the state when internal pressure is applied. It can be seen that all of the shapes become larger, and they grow in almost similar shapes. This is true for both circular and square cross sections. FIG. 4 shows a vertical section of a metal ring MR having a square cross-section groove on the outer periphery, 5 is the square cross-section groove, and FIG. 4-A shows a square tube 6 connected to the square cross-section groove 5. This shows the state in which they are fitted and no internal pressure is applied, and FIG. 4-B is a cross-sectional view of the state in which the internal pressure is applied. When internal pressure is applied, the side walls of the rectangular cross-sectional groove do not bulge laterally, but both the inner and outer diameters of the rectangular tube 6 become larger. Therefore, the concept of fixing the inner diameter side of this rectangular tube is shown in FIG. In other words, a square tube 8 with a steel band ring 7 embedded in the inner diameter side of the square tube 6 is connected to a metal ring MR.
It is set in the rectangular cross-section groove 5, as shown in Fig. 5-
A is a longitudinal section showing the state when no internal pressure is applied, and Fig. 5-B is a longitudinal cross-sectional view of the state when internal pressure is applied.
In this case, the inner diameter of the rectangular tube 8 does not change even if the inner pressure is applied, and only the outer diameter increases. The cross-sectional view of FIG. 6 shows a state in which a device having such a mechanism is inserted into the connecting pipe 9 and internal pressure is applied to the square tube 8. In this case, a square cross-section groove 5 is formed on the outer periphery. When a load W is applied to the metal ring MR in the direction of the arrow, the change in x, that is, the deflection is set as Δx, and the results are shown in the W-Δx curve in FIG. In FIG. 7, the vertical axis shows the load W (ton.), and the horizontal axis shows Δx (mm). A 400A steel pipe was used as the adhesive tube 9 used in this experiment, and a rubber-like elastic body made of an elastic polymer material had a shear modulus of 90 kg/cm ² . Although this W-Δx curve changes depending on the shear modulus and other design parameters, it can be seen from this example how large the centering force is. Note that this force is greatly influenced by the rigidity of the side wall portions 8a on both sides of the rectangular tube 8 , but is hardly affected by the internal pressure. The principle of a mechanism for aligning connecting tubes using this rectangular tube 8 will be explained with reference to a schematic diagram of the principle in FIG. In the figure, CTE is a skin matching device, which has a cylindrical base 10 with a hollow part 11 in the center.
A first rectangular cross-section groove 12 and a second rectangular cross-section groove 13 are provided as a rectangular cross-section groove FCS for fixing, and a third rectangular cross-section groove 14 is provided as a rectangular cross-section groove JCS for connection in the axial direction on the lower part of the welded part. It is formed into a protruding annular shape by providing a space part at an appropriate interval without causing any trouble by welding.Practically speaking, each side wall 12a, 13a, 14a of each square cross-section groove is located at the position of the above-mentioned square cross-section groove. Depending on the configuration, both side walls or one side wall are assembled on the outer periphery of the base body 10. This apparatus CTE uses a cylindrical base 10 for joining steel pipes, but it goes without saying that for irregular joining, bases having shapes corresponding to the respective shapes are used. The first, second and third rectangular cross-section grooves 12 , 13 ,
The rectangular tube 15 that fits into the tube 14 is shown as having an integral structure used in the explanation of the experiment, but in practice, the bottom part 15a and the side wall part 1
The airtight part 15d is formed by assembling the side walls of the rectangular cross-sectional groove by molding the two parts of the U-shaped annular part consisting of both sides of the 5b and the outer peripheral part 15c at the bottom, or The annular portion having a U-shaped cross section and the bottom portion 15a are formed by joining together in advance, and these are configured to be strongly assembled and fixed by assembling the side walls. Of course, the bottom portion 15a has the steel band ring 7.
A fixing ring 16 of the same type of metal is embedded, and fixes the lower surface of the U-shaped annular section of the square tube 15 to the bottom of the square cross-section groove in a non-stretchable manner similar to the bottom section 15a. Further, the embedded fixing ring 16 is provided with a metal fitting for joining the fluid introduction pipe from the base body 10. The figure omits the connection for fluid introduction. The rectangular tube 15 is made of a rubber-like material with high toughness and modulus made of an elastic polymer material, and has a high shear modulus. Moreover, between the second rectangular cross-sectional groove 13 and the third rectangular cross-sectional groove 14 , a space part TS is provided at the lower part of the welded part at a distance that does not interfere with welding.
The space can be used to test for leakage and strength of the welded joint. This embodiment is an example of a method for skin-to-bottom joining of the joining ends of the pipe body Pa and the connecting pipe Pb, as shown in FIG.
The CTE is placed in the pipe body Pa in the range of the first rectangular cross-sectional groove 12 and the second rectangular cross-sectional groove 13 , which are the rectangular cross-sectional groove FCS for fixing, and about 1/2 part, which is a part of the length of the space part TS. Insert the tubular body into the area between the remaining approximately 1/2 length of the space part TS and the third square cross-section groove 14 , which is the joint square cross-section groove JCS, as the connection skin-matching part CC.
It is set so that it is left protruding outside the Pa. In the case of joining both straight pipes to each other, two fixing square cross-section grooves are used. With this setting, when internal pressure is applied to the airtight portion 15d of the rectangular tube 15 of the first rectangular cross-sectional groove 12 and the second rectangular cross-sectional groove 13 , which are the rectangular cross-sectional grooves for fixing, the center line EC of the axis of the skin matching device CTE and the center line of the tube body Pa
It operates so that it is collinear with PaC, and the pipe body Pa
The cross-sectional ellipse distortion of is made into a perfect circle so that it becomes close to a perfect circle, and this skin matching device CTE is firmly fixed. Next, about 1/2 of the length of the space part TS left outside the pipe body Pa and the square cross-section groove JCS for joining.
Insert the adhesive tube Pb into the connection skin-matching portion CC consisting of the following. In that state, as shown, the adhesive tube Pb
The center line PbC is different from the center lines EC and PaC of the skin matching device CTE and the tube body Pa. In this state, next, when internal pressure is applied to the airtight portion 15d of the square tube 15 of the third square cross-sectional groove 14 , the center line PbC of the adhesive tube Pb, the center line EC of the skin matching device CTE, and the center line of the tube body Pa. It operates so that it is on the same line as the center line PaC, and the strain in the adhesive tube becomes a perfect circle, completing the skin alignment. Next, in this fixed state, the pipe body above the space part
The skin-matching portions of the mutual ends of Pa and the bonded tube Pb are welded to perform skin-to-skin joining of the joined ends. When joined, the space portion TS formed between the second rectangular cross-sectional groove 13 and the third rectangular cross-sectional groove 14 is
Since an airtight space is formed by pressurizing the rectangular tube 15 , if fluid (gas or liquid) at the required pressure is introduced into this space TS,
The airtightness test and strength test of the joint can be performed at the same time as skin-to-skin joining. Therefore, if there is no abnormality, buried pipes have the great advantage of being able to be immediately backfilled, and the conventional troublesome steps such as welding metal fittings for centering, adjusting wedges, and measuring preliminary dimensions are eliminated. In addition, there is no need to remove and repair the welded part of the alignment fitting, and there is no need to separately test the entire long pipe. It has remarkable features such as the ability to immediately perform local tests to check for leakage and the strength of welded parts by using the space at the bottom.
A particularly significant effect is that everything can be completed in a short period of time. The above-described embodiments have exemplified the case where straight pipes are connected to each other, but next, the case where a straight pipe and a curved pipe are joined will be described. In the case of this straight curved pipe joint, the skin matching device CTE used in the example of skin matching between straight pipes is too long and hits the inner wall of the curved pipe, so it is necessary to reduce the outside diameter and length of the device. be. Therefore, regarding the necessary repairs to square cross-section grooves and square tubes, Section 9
This will be explained with reference to FIGS. FIG. 9 is an explanatory enlarged partial sectional view showing the relationship between the rectangular cross-sectional groove 17 for a straight pipe and the rectangular tube 15 of the skin matching device in the case of joining a straight pipe and a curved pipe.
Because it is necessary to reduce the outer diameter OD of the side wall 17a of the rectangular cross-section groove 17 for straight bent pipes with respect to the inner diameter ID,
The clearance RI becomes relatively wide, and if the square tube 15 for mutual use of straight pipes of the previous embodiment is used in the square cross-sectional groove 17 for straight pipes, and the internal pressure of fluid is applied to the airtight portion 15d, as shown in the figure. The upper part of the side wall portion 15b protrudes into the gap and the withstand pressure becomes weaker. Therefore,
In the case of straight bent pipe joints, it is necessary to prevent this drop in pressure resistance. FIG. 10 is an enlarged partial cross-sectional view of the main part of the rectangular cross-sectional groove 17 for a straight curved pipe showing the reinforcing structure of the reinforced rectangular tube 18. The left half shows the state before internal pressure is applied to the airtight part 18d, and the right half shows the state before internal pressure is applied. This shows the condition when it is stretched. A unit fan-shaped metal plate 19 is installed in the entire side wall annular portion between the side wall 17a of the rectangular cross-section groove 17 for straight bent pipes and the side wall portion 18b of the reinforcing rectangular tube 18.A combination plan view of the unit fan-shaped metal plate 19 in FIG. As shown in the figure, many are inserted in a donut shape. Each of the unit fan-shaped metal plates 19 is provided with an annular protrusion 19a that fits into an annular groove 20 of the side wall portion 18b of the reinforcing square tube 18. Therefore, when internal pressure is applied to the reinforcing rectangular tube 18 , the unit fan-shaped metal plate 19 moves in the outer radial direction as the side wall portion 18b expands, and the reinforcing rectangular tube 1
8 is suppressed from protruding, and strong pressure is maintained. Similar to the previous embodiment, the reinforced square tube 18 forms a bottom portion 18a, a side wall portion 18b, an outer peripheral portion 18c, and an airtight portion 18d. Next, we will introduce the above-mentioned skin matching device CTE for joining straight bent pipes.
We will refer to the method of skin-to-skin joining of the joined ends. As shown in FIG. 12, this example illustrates the case of a straight pipe Pa and a bonded curved pipe Pc.
In the case of straight pipe joints, the square cross-section groove 17 (FCS) for fixing the straight pipe and the square cross-section groove 17 for connecting the straight pipe
(JCS) is used. As in the previous embodiment, at least one outer side wall of both side walls is constructed in an assembly manner on the outer periphery of the base body 10. Further, this reinforcing square tube 18 is manufactured in the same manner as the square tube 15 of the above embodiment except that an annular groove 20 is provided in the side wall part 18b.
8b is reinforced with unit fan-shaped metal plates and is configured to be strongly fixed by assembling the side walls of the rectangular cross-sectional groove. In this case, the unit fan-shaped metal plate 19 is inserted between the side wall 17a of the rectangular cross-sectional groove 17 for fixing and connecting the straight bent tube and the reinforcing rectangular tube 18 .
It is formed of these two identical square cross-section grooves 17 , one of which is used as the square cross-section groove 17 for fixing a straight curved pipe (FCS), and the other is the square cross-section groove 17 for connecting a straight curved pipe (JCS). A space portion TS is formed between the square cross-section grooves of both. Using this device, insert the rectangular cross-sectional groove 17 (FCS) for fixing the straight pipe into the straight pipe body Pa, and insert the range of about 1/2 part, which is a part of the length of the space part TS, into the straight pipe body Pa. The area between the remaining approximately 1/2 length of the section TS and the rectangular cross-section groove 17 (JCS) for joining the straight curved pipe is set as the skin-matching section CC for connection, so as to protrude outside the pipe body Pa. With this setting and maintaining the horizontal position, if internal pressure is applied to the airtight part 18d of the reinforcing square tube 18 in the square cross-section groove for fixing the straight curved tube, the center line EC of the axis of this device and the center line of the tube body Pa It operates so that it is on the same line as the PaC, and the distortion of the tube becomes close to a perfect circle and is firmly fixed. Next, connect the skin-matching part CC protruding outside the pipe body Pa.
Insert the connected curved pipe PC. In this state, as shown in the figure, the center line PcC of the connecting curved pipe PC is deviated from the center lines EC and PaC of the skin matching device CTE and the pipe body Pa. Next, the rectangular cross-section groove 17 for connecting a straight bent pipe.
When internal pressure is applied to the reinforced rectangular tube 18 of (JCS),
Matches the center line PcC of the connecting curved pipe PC. It is also possible to connect a straight pipe to a curved pipe in the opposite way. This skin matching device CTE, which is short in length and outer diameter, can be easily removed from the curved pipe after use. Although the apparatuses in each of the above embodiments are exemplified as having a hollow part, the base body does not need to be hollow and is not limited to this. This invention makes it possible to perform face-to-face jointing of many pipe bodies, such as straight pipes and straight pipes and straight pipes and curved pipes, in a short time, easily and suitably, and allows leakage tests and strength tests to be performed as is. , which has many of the features mentioned above.

[Brief explanation of drawings]

Fig. 1 is a front view showing how the conventional joint pipes are aligned with each other, Fig. 2 is a side view showing the state in which the U-shaped metal fittings are welded to the pipe body, and Figs. 3-A and B. FIG. 4-A is a cross-sectional view showing the state of a normal rubber tube before and after expansion, and FIG.
Figure 5-B is a vertical cross-sectional view showing the state in which internal pressure is applied to the square tube in the square cross-sectional groove of the metal ring, and Figure 5-A is a longitudinal sectional view showing the state in which a steel band ring is placed on the inner diameter side of the square tube set inside the metal ring. Fig. 5-B is a vertical cross-sectional view of the rectangular tube shown in Fig. 5-A with internal pressure applied, and Fig. 6 is a longitudinal cross-sectional view of the rectangular tube shown in Fig.
The figure is a vertical cross-sectional view showing the state in which Fig. 5-A is inserted into the connecting pipe and internal pressure is applied to the rectangular tube. Fig. 7 is a curve diagram showing the relationship between load W and deflection. FIG. 9 is a sectional view showing a mechanism for aligning straight pipes with each other using a matching device; FIG. 10 is an explanatory enlarged partial sectional view showing the relationship between a square cross-sectional groove and a square tube in the case of joining a straight pipe and a curved pipe; FIG. 11 is an enlarged partial cross-sectional view of a square cross-section groove showing the reinforcement structure of a reinforced square tube.
The figure is a plan view of a combination of unit fan-shaped metal plates, and FIG. 12 is a cross-sectional view showing a skin-matching mechanism for joining straight curved pipes using a skin-matching device. CTE...Skin alignment device, Pa...Pipe body, Pb...Connecting pipe, 10...Base body, FCS...Fixing square cross-section groove, 12 ...First square cross-section groove, 13 ...Second square cross-section groove , JCS... Square cross-section groove for connection, 14 ......
Third square cross-section groove, TS...space part, 15 ...
Square tube, 15d...airtight part, CC...connecting skin matching part, EC...center line of skin matching device, PaC
... Center line of tube body, PbC ... Center line between connections, 1
6...Fixing ring, 17 ...Square cross-section groove for fixing and connecting straight curved pipes, 17 (FCS)...Square cross-section groove for fixing straight curved pipes, 17 (JCS)...Connection of straight curved pipes Square cross-section groove, 18 ... Reinforced square tube, 18
d... Airtight part, Pc... Connecting curved pipe, PcC... Center line of connecting curved pipe, 19 ... Unit fan-shaped metal plate, 19a
... annular projection, 20 ... annular groove.

Claims (1)

[Claims] 1. One or two fixing square cross-sectional grooves and one connecting square cross-sectional groove are formed on the outer periphery of the base, and between the connecting square cross-sectional groove and the fixing square cross-sectional groove. At the bottom of the welded part, a space part is provided at an appropriate interval that will not be disturbed by welding, and in each square cross-sectional groove, a square tube or reinforcement made of a rubber-like material with high toughness and modulus with a non-extensible bottom part is installed. In the skin matching device that combines square tubes, one square cross-section groove for connection and the skin matching part for connection in the range of about 1/2 of the length of the space part are left, and the square cross-section groove for fixing and the space part are By inserting about 1/2 part into the tube body and introducing pressure fluid into the airtight part of the rectangular tube of the fixing rectangular cross-section groove or the reinforcing rectangular tube of the insertion part,
The center line of the matching device and the center line of the pipe body are made to match, and at the same time the distortion of the pipe is made into a perfect circle. Next, the connecting pipe or connecting curved pipe is connected to the above-mentioned skin matching part for connection left outside the pipe body. Pressure fluid is introduced into the airtight part of the square tube or reinforcing square tube of the square cross-section groove for connection, and the center line of the connecting tube and the center line of the tube body are aligned to perform skin alignment, and the mutual ends are After welding, the required pressure fluid is introduced into the space of the skin matching device to perform a leakage and strength test on the joint to confirm the completion of the joint. Skin-to-skin joining method. 2. The joint according to claim 1, in which the reinforcing rectangular tube is reinforced so that the reinforcing plate, which is formed by combining a large number of unit fan-shaped metal plates and set in a donut shape, moves in the outer radial direction as the side wall of the rectangular tube expands. Edge joining method.