JPH031794B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an induction heating method for heating the joints of metal pipes constituting the pipelines when lining the joints at the construction site. A method of forming a coil on the outer periphery of a long material such as the metal tube,
The present invention also relates to a jig for carrying out this method.

[Conventional technology]

When laying metal pipes forming pipelines,
When the pipe used is a lined pipe, the joint is lined at the installation site.

This on-site lining is performed by heating the joint portion to a predetermined temperature and supplying a lining material such as an appropriate synthetic resin powder to the heated portion, thereby fusing the lining material to the joint portion to form a film. .

The heating means for the above-mentioned on-site lining include:
Induction heating is often used because it can achieve uniform heating temperatures in a short period of time, but in the past, it had the disadvantage that it required a lot of effort to form the heating coil around the metal tube being installed. Ta.

[Problem to be solved by the invention]

In other words, the conventional method for forming heating coils for on-site lining is to wrap asbestos cloth as a heat insulating material or insulating material around the part of the metal pipe that has been laid in an excavated trench that is to be lined. A method is adopted in which a required number of turns of cable is wound on the cloth to form a heating coil. These cables are often hollow tubes with a coil cooling channel in the center, and are therefore large in diameter and quite heavy, making it difficult to wrap them manually as described above. Not only was it difficult, but the work efficiency was low, hindering the overall efficiency of on-site lining work. Moreover, since the cable was wound manually, the groove in the area where the cable was wound had to be dug deeper later for this winding work, which was troublesome. The above-mentioned difficulties are not limited to heating in on-site lining, but also apply when heat treatment is performed on-site to improve the material quality of joints.

[Means to solve the problem]

The present invention can save labor by using an appropriate long cable when it is necessary to apply induction heating to a long material such as a metal pipe that is being installed at the construction site, as in the case of lining the metal pipe that is being installed as described above. This method was developed with the aim of providing a method for efficiently forming an induction heating coil, and a coil forming jig used to implement this method. Two annular frames formed by connecting and fixing divided annular members are attached to the outer circumferential portion of a long material to be heated, such as at an appropriate distance in the length direction of the long material. A coil forming jig configured by connecting the frames with a substantially cylindrical connecting frame that has an inner diameter that appropriately separates the frames from the outer surface of the elongated material and is rotatably formed around the elongated material. A heating coil is formed by attaching an appropriate cable to the connecting frame of the jig and rotating the connecting frame so that the cable is wound around the connecting frame, and The structure of the coil forming jig for carrying out this method is that the coil forming jig has an inner diameter larger than the outer diameter of a long material such as a metal tube, and is formed by connecting and fixing divided annular members. A cylindrical frame is formed by an annular frame and a substantially cylindrical connecting frame that connects and fixes these, and the connecting frame is spaced evenly apart from the long material on the inner peripheral side of the cylindrical frame. A support ring is provided around the long material to support it rotatably, and one end of an induction heating cable is attached to the surface of the connecting frame, and the connecting frame is attached to the long material. The heating coil formed by the cable can be wound around the connection frame by rotating the cable around the connecting frame.

〔Example〕

Next, an embodiment of the method of the present invention will be described using an example of a coil forming jig.

In FIGS. 1 and 2, 1 indicates an annular frame, and semi-circular annular members 1a and 1b are divided into two.
A connecting piece 1c is formed at the joint. The connecting pieces 1c are connected to each other by being tightened by a tightening member 1d such as a bolt/nut, thereby forming the annular frame 1.

In this embodiment, two of the annular frames 1 are replaced with steel pipes B, which are an example of a long material such as a metal pipe to be heated.
are spaced apart on the same axis of the steel pipe B.
are connected and combined by a cylindrical connecting frame 2 on the outer circumference to form a cylindrical frame A having a cage shape as a whole, and this is used as a coil forming jig in the present invention. In addition, 2a is the above-mentioned connection frame 2
This is a cable wrapping guide formed on the outer surface of the cable.

Thus, each part of the inner surface of the cylindrical frame A is positioned at an equal distance from the outer surface of the steel pipe B, and the cylindrical connecting frame 2 can rotate around the steel pipe B. Four support rings 3 are provided radially toward the inside. The amount of protrusion of each support ring 3 can be adjusted so that the tip thereof always comes into contact with the outer surface of the steel pipe B, regardless of the size of the outer diameter of the steel pipe B. Here, a flexible wheel having a height adjustment part 3a using a screw is used, whereby the cylindrical frame A is in a state where it can rotate and move around the outer periphery of the steel pipe B in the manner shown in the second figure. This constitutes an example of the coil forming jig of the present invention.

After arranging the cylindrical frame body A around the outer periphery of the steel pipe B to be induction heated as described above, the cable 4 to be formed into a heating coil is wound around the cylindrical connecting frame 2 as shown in FIG. However, when wrapping the cable 4 around the outer surface of the connecting frame 2 as shown in Figure 1, the tip end of the cable 4 is temporarily fixed to the guide 2a in front of the connecting frame 2, and then When the cylindrical frame body A itself is rotated relative to the steel pipe B, the cable 4 is sequentially wound around the connection frame to form a heating coil.

In another embodiment shown in FIG. 3, the annular frame 1 of the example shown in FIG. It has a structure formed in a shaped frame body A'.

In this way, the annular frame 1 does not need to rotate, so a normal wheel is sufficient as the support wheel 31 that contacts the steel pipe B, and only the cylindrical connecting frame 2' rotates.

It should be noted that the cable 4 may be a coaxial cable with a cooling water passage formed therein or a suitable cable having another structure in order to prevent the cable itself from being heated due to radiant heat during heating.

Cable 4 to the above cylindrical connecting frame 2 or 2'
The cable 4 is wrapped around the connecting frame 2 due to the winding mode.
Alternatively, it can be wound in a multi-turn coil shape from the front to the rear on the outer surface of 2'. In addition, when winding the cable around the inner surface of the connecting frame 2', the tip of the cable is slid onto the inner surface of the cylindrical frame A' and rotated, thereby creating a multi-turn coil as shown in Fig. 3. It is also possible to form

In the present invention, a non-inductive material is used for the structure of the cylindrical connecting frame 2 around which the cable is wound so that it does not interfere with induction heating of a long material such as a metal tube, or In order to block heat radiation from the heated elongated material, the elongated material may be wrapped in asbestos or the like.

Furthermore, in any coil formation, the cable 4 can be wound partially or entirely in two or more stages. In addition, in order to set the winding pitch to a predetermined pitch or to make various changes, the winding guide 2a or 2a may be formed by a groove formed on the surface of the cylindrical connecting frame 2 or 2' in the direction in which the cable 4 is wound. This can be easily done using 2a'. When the cable 4 is wound around the outer surface of the cylindrical connection frame 2 or 2', the rotation of the connection frame 2 or 2' may be performed using the rotational driving force of a motor or the like.

It is important that the coil forming jig of the present invention has a generally cylindrical outer shape and is formed to be rotatable relative to a long material such as a metal tube, and is formed only from the structural members of the embodiment. It does not have to be able to be divided or assembled freely. Further, as long materials to which the present invention can be applied, in addition to the above examples,
There are metal columns and metal beams.

〔Effect of the invention〕

The present invention is as described above, and by using the cylindrical frame that is the coil forming jig of the present invention, conventionally, each turn of the cable was manually wound around a long material such as a metal tube. Therefore, it was difficult and inefficient to form an induction heating coil, but it is extremely labor-saving and efficient because an induction heating coil using a cable can be formed around the outer circumference of a long material by simply rotating the connecting frame. A heating coil can be formed.

In particular, when the coil forming jig of the present invention is used to form a heating coil by winding a cable as long as 100 m, the above-mentioned effects will be extremely significant.

In addition, in the above-mentioned coil forming jig, since the annular frame is usually provided with a support ring that can run in the axial direction, for example, when heating is to be performed at multiple locations on a metal pipe being laid, it is possible to It can be easily moved to the next heating site as is, and in this respect as well, there is an effect that cannot be obtained with the prior art. However, if the support wheel is not a running wheel, for example, even if it is just a height adjustment rod, movement is possible as long as there is some play between it and a long material such as a metal tube.

The coil forming jig according to the present invention assembles a cylindrical frame from an annular frame and a connecting frame onto the outer periphery of, for example, a steel pipe that is being laid at a construction site and attaches it as a coil forming jig. By rotating the cable and winding the cable, a coil for induction heating can be formed, and it is easy to disassemble, assemble, and
Alternatively, since it can be transported and stored, it is extremely useful as a coil forming jig at the construction site.

As described above, when it is desired to partially heat a long material such as a metal pipe being laid at a construction site, the present invention can easily heat a long material such as a metal pipe by wrapping a cable around a rotary cylindrical frame that is easy to install. It is also possible to efficiently form induction heating coils for ancillary work on the long materials, making it extremely convenient for on-site lining work and heat treatment work, which were extremely difficult in the past. can bring.

Therefore, the present invention is particularly useful as a method for forming an induction heating coil at a metal pipe installation site, and as a heating coil forming jig used when carrying out this method.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing an example of the jig of the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a front view of another example with the lower half thereof sectional. A, A'...Cylindrical frame, 1...Annular frame, 1c...
...Connection piece, 1d...Tightening member, 2...Cylindrical connection frame, 2a...Wrapping guide, 3...Support ring, 4...
Cable, B...steel pipe.

Claims (1)

[Claims] 1. Two annular frames formed by connecting and fixing divided annular members are attached to the outer peripheral portion of a long material such as a metal pipe that is being installed at a construction site to be heated. A substantially cylindrical shape that is attached at appropriate distances in the longitudinal direction of the length of the length, has an inner diameter that appropriately distances the annular frame from the outer surface of the length of the length, and is rotatably formed around the length of the length of the length. Equipped with a coil forming jig constituted by connecting with a connecting frame forming a coil forming jig, attaching an appropriate cable to the connecting frame of the jig, and winding the cable around the connecting frame by rotating the connecting frame. A method for forming an induction heating coil, the method comprising forming a heating coil. 2. Two annular frames that have an inner diameter larger than the outer diameter of a long material such as a metal tube and are formed by connecting and fixing divided annular members, and a substantially cylindrical connecting frame that connects and fixes them. to form a cylindrical frame body, and the connecting frame is supported on the inner peripheral side of the cylindrical frame body with an equal distance from the long material, and is rotatable around the long material. A supporting ring is provided to support the connecting frame, one end side of the induction heating cable is attached to the surface of the connecting frame, and the connecting frame is rotated around the long material, so that the cable is attached to the connecting frame. An induction heating coil forming jig, characterized in that it is capable of winding and forming a heating coil.