JPS5927862B2 - How to thread wire etc. into piping - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for inserting a wire or the like into a pipe.

Piping for equipment that handles high temperatures, high pressures, or special gases must be inspected for corrosion, cracks, etc. after a certain period of use for safety reasons.

For example, in order to inspect the pipe from the inside, a probe for nondestructive testing is inserted into the pipe, and the probe is moved along the entire length of the pipe to check for defects. In such cases, usually a pilot wire such as a piano wire is passed through the tube in advance, the probe and a signal transmission cord are tied together, and the pilot wire is pulled to draw the probe or the like into the tube and move it. However, this method can only be applied to pipes with a simple shape or pipes that are not very long, and when the length of the pipe is several tens of meters, such as a pipe with a complicated shape or many curves, the length of the pipe can be reduced. The wire may rub strongly against the pipe wall at the bend, increasing the frictional force, or the wire may become twisted or tangled, making it impossible to remove the pilot wire even if the pilot wire is pulled. The purpose of the present invention is to provide a method for inserting wires, electric cords, etc. (referred to as wires, etc.) into pipes, which eliminates the above-mentioned drawbacks. Connect the tip of the wire or the like that was attached to the pipe to the rear end of the piston head inserted into the pipe, and apply fluid pressure by flowing pressure fluid from the rear of the piston head.
The piston head is advanced while leaking fluid from the piston head forward, and a thrust is applied to a support attached to the wire to draw the wire into the pipe, and the speed is determined by the rotation of the wire guide drum. This relates to a method for inserting a wire or the like into a tube, which is controlled by adjusting the .

Next, embodiments shown in the accompanying drawings will be described.

One end 1a of the pipe 1 is open to the atmosphere, and the other end 1b is connected to a pressure vessel 2 with a flange 3. A flexible thin piano wire, nylon rope, or the like is used as the wire 4 inserted through the pipe 1, and supports 5 are attached at predetermined intervals. The support 5 is made of a material such as Teflon or plastic, and has a hollow spherical shape as shown in FIG. 2 or a spherical brush shape as shown in FIG. 3 to reduce the coefficient of friction against the inner wall of the tube. In the case of a solid support such as a hollow sphere, it is convenient to attach it rotatably to the wire etc. 4 to prevent the wire etc. from twisting. The spacing between the supports 5 is determined depending on the shape of the pipe, the bending radius of the pipe, the type of wire, etc., so as to prevent the wire inserted into the pipe from coming into direct contact with the inner wall of the pipe and causing friction. The interval should be appropriate. The tip of the wire 4 is tied to a traction piston head 6 that slides along the inner wall of the tube. It is preferable that the piston head 6 has a plurality of seat pad rings 6a attached thereto, for example, as shown in FIG. 4, so that it can easily fit into the inner wall of the pipe. A small hole 6b is made in the piston head, or a gap is provided between the seat packing 6a and the pipe to allow some of the pressure fluid to leak out. If pressurized fluid is allowed to flow from the rear of the piston head in this way, pressure and fluid flow will be generated inside the tube, generating thrust on the support inside the tube, reducing the apparent frictional resistance, and moving the piston forward inside the tube. It's easy and convenient. When this method is used for non-destructive testing, a probe is mounted in front of the traction piston head 6, for example. pressure vessel 2
has a volume capable of storing the wire 4 with a support, and a guide drum 7 for the wire 4 is rotatably provided above it. Further, a pressure fluid such as compressed air, nitrogen gas, or water is supplied to the pressure vessel 2 through a pipe 8. In this way, wires, etc. 4, to which supports 5 of the required length are attached according to the length of the piping 1, are sequentially placed into the pressure vessel 2 so as not to get tangled when being pulled out. The support 5 is hung on the pawl 7a of the guide drum 7, the traction piston head 6 is inserted into the pipe 4, and the flange 3 connects the pipe 1 and the pressure vessel 2 in an airtight or watertight manner.

When pressure fluid is sent from the pipe 8 into the pressure vessel, the pressure fluid flows into the pipe and applies pressure to the back surface of the piston head 6. Since a small hole is provided in the piston head 6 to allow some of the pressure fluid to leak through it, when pressure starts to be applied to the back of the piston head, the pressure fluid leaks from the small hole 6b, so even if the piston head 6 does not move. If a larger amount of pressure fluid flows into the pipe from the pressure vessel than the leakage amount, a traction force is generated on the piston head 6, and a thrust force due to the dynamic pressure of the pressure fluid acts on each support 5, so that the apparent frictional resistance is reduced. It is smaller, making it easier to insert wires etc. into complex piping. If the speed at which the wire etc. 4 is drawn into the pipe is adjusted by adjusting the rotation of the guide drum 7 from the outside, it will prevent the wire etc. from being pulled in suddenly and becoming twisted, or the supports becoming entangled with each other. This can be prevented. As explained above, when using this method, a support with a small friction coefficient is attached to the wire, etc., and the wire, etc. is supported so that it does not rub against the inner wall of the pipe and generate a large frictional force. Low resistance to insertion.

In addition, pressurized fluid is used to insert the wire, etc., and the piston head connected to the wire, etc. is moved forward inside the pipe while leaking the pressure fluid forward from the piston head, and the wire, etc. is pulled into the pipe, so the piston A forward flow of pressure fluid occurs at the rear of the head, and a thrust force due to the dynamic pressure of the pressure fluid acts on each support. It is now possible to insert wires etc. into the inside, and there is no need to insert a pilot wire in advance. The support has good mobility within the pipe, and because it vibrates due to the flow of fluid, there is no risk of it becoming clogged within the pipe. Furthermore, since the speed of the wire, etc. is controlled by the guide drum, great effects can be obtained, such as fewer accidents such as twisting or tangling of the wire when the wire is drawn out from the container.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining an embodiment of the method of the present invention, FIG. 2 is a central vertical cross-sectional end view showing an example of a support, and FIG. 3 is a central vertical cross-sectional view showing another example. FIG. 4 is a partially exploded side view showing an example of a piston head located within a tube. 1...Pipe, 2...Pressure vessel and containment vessel for wires, etc., 3...Flange, 4...
Wire, 5... Support, 6... Piston head for traction, 7... Guide drum, 8...
...Pipe for pressure fluid.

Claims (1)

[Claims] 1 In a method in which a piston head connected to a wire, etc. is inserted into a pipe, and fluid pressure is applied to insert the wire, etc. into the pipe, one end of the wire, etc., to which supports with a small coefficient of friction are attached at a predetermined interval, is inserted into the pipe. The piston head is connected to the rear end of the piston head inserted into the piston head, and pressurized fluid flows into the pipe from the rear of the piston head to apply fluid pressure, and the piston head is advanced while leaking fluid from the piston head to the front thereof. The wire, etc. is drawn into the pipe by applying a thrust to a support attached to the wire, etc., and the speed of the wire, etc. is controlled by adjusting the rotation of a guide drum for the wire, etc., into the pipe. How to insert it.