JP4184548B2 - Pushing jig and welding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a pressing jig used for pipe welding in which pipes such as gas pipes are butted and connected, and a pipe welding method using the jig.
[0002]
[Prior art]
Conventionally, a ring-shaped backing copper plate that also serves as a clamp by automatic welding when a horizontal fixed pipe such as a gas pipe is abutted and connected in the longitudinal direction has been often used. For example, as shown in FIG. 9, the backing copper plates 35... 35 are pressed by the moving device 30 from the inside of the pipes 36 and 36 along the abutting portion. The moving device 30 travels inside the pipe, and has a cylindrical body portion 31 and traveling wheels 32... 32 that are attached radially from the body portion and contact the inner surface of the pipe to cause the moving device 30 to travel. Similarly, an air cylinder (not shown) that is attached so as to extend radially from the body 31 and presses the backing copper plate outward in the radial direction, and an air tank 34 that supplies air to the air cylinder are provided. The backing copper plates 35... 35 are attached so as to cover the tips of the air cylinders from the outside in the radial direction. Then, during welding, the air cylinder is pressed against the abutting portion 37 from the inside of the pipes 36 and 36 to prevent the weld metal from melting into the piping 36 and 36 from the gap formed in the abutting portion 37. Yes.
[0003]
[Problems to be solved by the invention]
However, this apparatus is large enough to tighten most of the pipe diameter, and it is very difficult to put in and out and run in the pipe unless the pipe is formed in a straight line.
[0004]
In addition, when replacing the middle part of an existing pipe, the pipe is cut to a predetermined length, and then a new pipe of the same size is inserted. It was difficult to perform automatic welding as it was.
[0005]
Therefore, in the present invention, when pipes that are bent or curved are connected, or when a part of the existing pipe is replaced, pipe welding can be easily performed even if a wide groove gap is formed. A pressing jig to be used and a pipe welding method using the jig are provided.
[0006]
[Means for Solving the Problems]
In the invention of claim 1, in the pressing jig that abuts the pipes along the abutting portion from the inside of the piping when the pipes are abutted in the longitudinal direction and the abutting portion of the piping is welded, The outer peripheral portions are connected to each other in a chain shape via an annular wire, so that the entire pressing jig is curved in a ring shape so as to abut against the abutting portion and can be pulled out of the pipe. And a plurality of backing pieces each extending in a straight line as the entire pressing jig, each having the same curvature, and a leaf spring for urging these backing pieces radially outward from the inside, One end of the leaf spring is attached to the back surface of the backing piece at the outermost portion with a wire, a wire rope is attached to the backing piece, and the backing piece and the leaf spring are in contact with each other. From an opening formed in the tube wall in the vicinity of the part, in a state of being extended in a straight line having an insertable size in the pipe, by pulling on the wire rope, the pipe outer from the opening The above-mentioned problem is solved by being able to be pulled out.
[0007]
According to the present invention, the state of the pressing jig (1, 11, 16) can be freely changed between a linearly extending state and a ring-shaped state. Therefore, for example, the inside of the pipe (8, 9, 22, 23) such as the gas pipe (10) that is installed as a whole or the gas pipe (21) in which the elbow (23) bent at a right angle exists is provided. Even when repairing the pipes (8, 9, 22, 23) that cannot use the moving device (30) that moves, the openings (8a, 8) provided in the vicinity of the butt portions (9, 24) to be welded 23a), the pushing jig (1, 11, 16) can be easily inserted from the openings (8a, 23a). The backing piece (2, 12, 17) can be brought into contact with the butting portion (9, 24) from the inside of the pipe (8, 9, 22, 23) very easily.
[0008]
According to a second aspect of the present invention, in a pipe welding method in which pipes are butted in the longitudinal direction, the butted parts of the pipes are welded and connected to each other, the outer peripheral parts of the ends are chained together via an annular wire. By being connected in a shape, the entire pressing jig is curved in a ring shape so as to contact the abutting portion, and the entire pressing jig extends linearly so that it can be inserted into the pipe. A plurality of backing pieces each having the same curvature and formed in an arc shape, and a leaf spring for urging the backing pieces from the inside to the outside in the radial direction, one end of the leaf spring being the back end of the end portion It is attached to the back surface of the abutting piece with a wire, and a pressing jig with a wire rope attached to the backing piece is inserted into the pipe from the opening formed in the tube wall near the abutting portion. and, Serial by contact with the backing piece from the inside of the pipe along the abutting section, the weld metal inside the pipe from the gap of the butt portion connected to the pipe together while preventing the burn through After the connection, the wire rope is pulled to pull the pressing jig out of the pipe from the opening in a state where the pressing jig is extended linearly .
[0009]
According to the present invention, a pressing jig capable of freely changing the state between a linearly extended state and a ring-shaped state can be easily inserted into a pipe (8, 9, 22, 23). Even if (8, 9) is curved or provided with an elbow (23), it is possible to easily connect the pipes (8, 9, 22, 23) and weld them.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
1 and 2 show an embodiment of a pressing jig 1 according to the present invention. As shown in FIG. 1, the pressing jig 1 has a plurality of backing pieces 2... 2 each having a copper plate formed in an arc shape with the same curvature, and these backing pieces 2. Wires 3... 3 connected in a chain are provided, and a leaf spring 4 as a belt -like urging member attached to the back surface of the backing piece 2 at the end of the wire with a wire 5. The leaf spring 4 is attached so as to coincide with the extending direction of the backing pieces 2.
[0012]
The backing pieces 2 ... 2 are connected to each other by a wire 3.3 ... 3 so that they can be bent freely, and the pressing pieces 2 ... 2 are formed in an arc shape having the same curvature. As shown in FIG. 2, the pressing jig 1 can be curved so that the overall shape is substantially ring-shaped.
[0013]
The pressing jig 1 is used when, for example, repairing a curved gas pipe 10 as shown in FIG. 3, the gas pipes are butted together and the butted portions are welded together. FIG. 3 shows a state in which the existing gas pipe 10 is partially exchanged only in the portion provided with the opening / closing valve 7. The existing gas pipe 10 is cut before and after the opening / closing valve 7 in the longitudinal direction, and thereafter, a pipe 6 having substantially the same size and having the opening / closing valve 7 is newly inserted. In the pipes 8 and 8 at both ends of the inserted pipe 6, openings 8 a and 8 a are respectively provided in the immediate vicinity of the pipe 6. Prior to the repair, another pipe is erected upward from the pipes 8 and 8 at the openings 8a and 8a, and for example, a gas meter is provided in the pipe. The openings 8a and 8a are formed by cutting this pipe.
[0014]
The pressing jig 1 is inserted into the inside of the pipe 8 through the opening 8a in a state where the pressing jig 1 is linearly extended. Then, a hand is inserted into the inside of the pipe 8 through the opening 8a, and the pressing jig 1 is moved to the butting part 9 between the pipe 6 and the pipe 8 as shown in FIG. At this time, the pressing jig 1 is moved inside the pipe 8 while being formed in a substantially ring shape in the circumferential direction so that the backing pieces 2... 2 are positioned outside the leaf spring 4. Then, the backing pieces 2... 2 are contacted from the inside of the gas pipe 10 along the abutting portion 9 and welded from the outer periphery of the gas pipe 10 to the groove formed in the abutting portion 9. Connect the pipe 8.
[0015]
The backing pieces 2... 2 are biased almost uniformly outward in the radial direction by the leaf springs 4, so that the backing pieces 2. 2 are stationary at the position of the abutting portion 9 without being displaced. The weld metal is prevented from melting into the gas pipe 10 and the back bead of the welded portion is prevented from being oxidized. Further, the backing pieces 2... 2 of the pressing jig 1 form a smooth back bead to prevent the gas flowing inside the gas pipe 10 from being turbulent at the welded portion.
[0016]
If a long and thin wire rope is attached to the pressing jig 1, the pressing jig 1 inserted into the gas pipe 10 can be removed from the gas pipe 10 by simply pulling the wire rope after welding. Can be convenient.
[0017]
FIG. 5 shows another embodiment of the pressing jig 11 according to the present invention. The pressing jig 11 includes a plurality of backing pieces 12... 12 each having a copper plate formed in an arc shape having the same curvature, and these backing pieces 12. A wire 13... 13 and a coil spring 14 having an end surface attached by a wire 15 on the back surface of the backing piece 12 at the end. The coil spring 4 is attached so as to coincide with the extending direction of the backing pieces 2.
[0018]
The pressing jig 11 can also be bent so that the entire shape is substantially ring-shaped with the coil spring 14 on the inside, and the butted portion between the pipes is attached with a weak force from the inside to the outside. The backing pieces 12... 12 can be brought into contact with the abutting portion while being urged.
[0019]
6 and 7 show still another embodiment of the pressing jig of the present invention.
[0020]
In this pressing jig 16, a plurality of backing pieces 17... 17 formed of a copper plate in the shape of an arc having the same curvature are connected to each other by wires 18. A bag body 19 is provided on the back surface of. The bag body 19 is attached to a backing piece 17 having an end portion provided at an end portion by a hook-and-loop fastener 20.
[0021]
The bag body 19 is provided with a filling portion 19 a for filling air into the end portion on the opposite side to the end portion attached to the backing piece 17. When the bag 19 is filled with air from the filling portion 19a, the bag 19 expands from the state shown by the solid line in FIG. 6 to the state shown by the broken line. Then, when the entire pressing jig 16 is curved in a substantially ring shape as shown in FIG. 7, a force to return the bag body 19 to a straight state is applied, and the backing pieces 17. Energize to.
[0022]
In addition to what has been described above, a rubber material having excellent heat resistance may be used as the urging member.
[0023]
As mentioned above, although the case where this invention is applied to the gas pipe arrange | positioned entirely curved was demonstrated, it is not limited to this, For example, as shown in FIG. It can also be adapted.
[0024]
The gas pipe 21 shown in FIG. 8 includes a short cylindrical pipe 22 extending linearly and elbows 23 and 23 bent at right angles provided at both ends of the pipe 22. In the gas pipe 21, the pressing jig according to the present invention is used when the butted portions 24 and 24 of the pipe 22 and the elbows 23 and 23 are brought into contact with each other. The pressing jig is inserted by hand from the openings 23a and 23a on the end surfaces of the elbows 23 and 23 to the position of the butting portions 24 and 24. And it is formed in a substantially ring shape inside the abutting portions 24, 24, and the backing piece is used in contact with the abutting portions 24, 24.
[0025]
【The invention's effect】
As described above, according to the present invention, even when the pipe is curved or has a portion bent at a right angle, the pressing jig is inserted into the pipe very easily when the pipes are butted against each other and welded. be able to. For this reason, the weld metal does not melt into the pipe at the butt portion to be welded. Further, the back bead of the welded portion can be formed smoothly, and turbulent flow is not formed in the fluid such as gas flowing in the pipe.
[Brief description of the drawings]
FIG. 1 is a front view showing a state in which a pressing jig according to an embodiment of the present invention is extended.
FIG. 2 is a front view showing a state where the pressing jig of FIG. 1 is bent in a ring shape.
FIG. 3 is a perspective view showing one mode of a gas pipe in which the pressing jig shown in FIG. 1 is used.
FIG. 4 is a longitudinal sectional view of a gas pipe showing a state where a pressing jig is used at a welded portion of the gas pipe.
FIG. 5 is a front view of a pressing jig according to an embodiment different from the pressing jig of FIG. 1;
6 is a front view showing a state in which a pressing jig according to another embodiment different from the pressing jig shown in FIGS. 1 and 5 is extended. FIG.
7 is a front view showing a state where the pressing jig of FIG. 6 is bent in a ring shape. FIG.
FIG. 8 is a perspective view showing one embodiment of a gas pipe provided with an elbow.
FIG. 9 is a side view of a moving device provided with a pressing copper plate that is used when welding a conventionally used gas pipe.
[Explanation of symbols]
1,11,16 Pushing jigs 2,12,17 Backing pieces 4,14,19 Biasing bodies 9,24 Butting parts 10,21 Gas pipe 19 Bag body 20 Surface fastener 23 Elbow

Claims (2)

In the pressing jig that abuts along the abutting part from the inside of the pipe when the pipes are butted together in the longitudinal direction and the abutting part of the pipe is welded,
The outer periphery of the ends are connected to each other in a chain via an annular wire, so that the entire pressing jig can be bent into a ring shape so as to abut against the abutting portion, and can be pulled out of the pipe. In this way, the pressing jig as a whole is provided with a plurality of backing pieces that extend linearly and are each formed in an arc shape with the same curvature, and a leaf spring that biases these backing pieces radially outward from the inside. One end of the leaf spring is attached to the back surface of the backing piece at the extreme end by a wire, a wire rope is attached to the backing piece, and the backing piece and the leaf spring are from the mating opening which is formed in the tube wall in the vicinity of, in a state of being extended in a straight line having an insertable size in the pipe, by pulling on the wire rope, the pipe through the opening Jig Pushing characterized that it is drawable. In the welding method for piping, in which the pipes are butted in the longitudinal direction, the butted portions of the pipes are welded and these are connected,
The outer periphery of the ends are connected to each other in a chain via an annular wire, so that the entire pressing jig can be bent into a ring shape so as to abut against the abutting portion, and can be inserted into the pipe. In this way, the pressing jig as a whole is provided with a plurality of backing pieces that extend linearly and are each formed in an arc shape with the same curvature, and a leaf spring that biases these backing pieces radially outward from the inside. One end of the leaf spring is attached to the back surface of the backing piece at the outermost portion by a wire, and a pressing jig to which a wire rope is attached is attached to the backing piece in the vicinity of the butting portion. inserted from the tube wall to form the opening in the pipe, said along the backing piece from the inside of the pipe to the abutting portion abutted, welding from the gap of the butt portion inside the pipe Metal melts Connecting said pipe to each other while preventing, after the connection ends, the jig Te the pushing and pulling the wire rope, the pipe outer from the opening in a state where the jig Te said pressing is extended in a straight line A method of welding pipes characterized by being drawn out.

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