JPH0160356B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for reducing the consumption of shielding gas such as argon used when performing TIG welding of piping.

When TIG welding pipes from the outside, the inside of the pipe must be in a shielding gas atmosphere such as argon or helium. For this reason, if the entire interior of the pipe is filled with shielding gas, a large amount of expensive shielding gas will be consumed, so various devices have been devised to confine the gas to the welding area. One of them is a device in which two disk-shaped elastic sealing materials are connected with a rope at a predetermined interval. This device moves one end of the device with a rope and moves it inside the pipe so that the weld is located between the sealing materials, and fills the shielding gas only between the sealing materials, reducing gas consumption. be. This device is useful when there are many welding points in the temporarily assembled piping, as it can be moved sequentially, but it cannot be used if the piping has bends. This is because when this device is moved by a pulling rope, the sealing material is pulled diagonally with respect to the center axis of the tube by the pulling rope at the bent part, so the sealing material is strongly pressed against the inner surface of the tube in one direction, and due to the friction. This is because it stops moving.

The object of the present invention is to eliminate such drawbacks and to improve the above-mentioned device so that it can be used even in pipes having bent portions.

That is, the present invention provides a guide wheel in front of each sealing material that contacts the inner surface of the tube at two places in the front and back direction,
The rear end of this guide car and the sealing material are connected by a universal joint located at a position that passes approximately through the center of the pipe when passing through the bent portion of the pipe, and a wheel is further provided at the rear of the front sealing material to prevent excessive deformation of the sealing material. It is something.

Next, the present invention will be explained with reference to illustrated embodiments. Reference numeral 10 denotes a front guide vehicle, which is pulled by a rope 12, and has four wheels 14,..., 16,... protruding in each direction at two locations in the front and back directions, and two of these wheels at each location.
The inner surface of the tube 18 is in contact with the inner surface of the tube 18. Reference numeral 20 denotes a front sealing material, which is made of a disc-shaped elastic body and is in contact with the inner surface of the tube 18. As this elastic body, a closed-cell foamed plastic, a laminated structure of open-celled foamed plastic and paper, etc. are used. The center part 22 of the front sealing material 20 is connected to the rear end of the front guide wheel 10 and a universal joint 24 located at a position that passes approximately through the center of the pipe when passing through the bent part of the pipe.
connected via. Four wheels 26 are provided near the outer periphery of the rear part of the front sealing material 20, and are in contact with the inner surface of the tube 18 to prevent excessive deformation of the sealing material. A rear guide wheel 28 has the same configuration as the front guide wheel 10, and is connected to the rear of the front sealing material 20 via a rope 30. 32 is a rear sealing material, which has the same structure as the front sealing material 20. A central portion 34 of the rear sealing material 32 is connected to the rear end of the rear guide wheel 28 via a universal joint 36 located at a position passing approximately through the center of the tube when passing through the bent portion of the tube.

Since this device has the above configuration, it is used as follows. First, as shown in FIG. 3, the rope 12 and gas hose 38 are inserted into the temporarily assembled piping 18. Next, one end of the rope 12 is connected to the front guide wheel 10, the gas hose 38 is passed through the front sealing material 20, and the ends are connected to both sealing materials 20,
It is located between 32 and 32. Next, pull the rope 12,
The entire apparatus is drawn into the pipe 18, moved so that the welding part 40 is positioned between the two sealing materials as shown in FIG. 1, and shielding gas is fed between the two sealing materials through the gas hose 38 to perform welding.
If there are multiple welding locations, the device is further moved and welding is performed one after another in the same manner as above. Finally, the rope is pulled and the device is pulled out from the end of the pipe, completing the work.

In the device of the present invention, each sealing material is not pulled directly by a rope, but from a position where the central part passes approximately through the center of the tube by a universal joint connected to the rear end of the guide wheel. The sealing material is not pressed in one direction on the inner surface of the tube, and the sealing material moves smoothly. In addition, wheels are provided at the rear of the front sealing material to prevent excessive deformation of the front sealing material, so that the rear sealing material deforms due to the frictional force with the inner surface of the pipe at bent portions of the pipe. Even if the front seal material is pulled diagonally to the center axis of the pipe and pressed against the inner surface of the pipe in one direction, the front seal material will not deform excessively, and therefore the part of the front seal material that is pressed against the inner surface of the pipe will be in the opposite direction. Seal leakage on the outer periphery is prevented, and movement becomes smoother.

Therefore, the device of the present invention can be used even with pipes having bent portions, and has the feature of reducing the amount of shielding gas consumed.

[Brief explanation of drawings]

FIG. 1 is a front cross-sectional view showing an embodiment of the present invention in use, FIG. 2 is a cross-sectional view taken along the - line in the previous figure, and FIG. 3 is a perspective view of piping in which the present invention is used. 10... Front guide wheel, 12... Rope, 14, 16
...Wheel, 20...Front sealing material, 22...Center, 2
4...Universal joint, 26...Wheel, 28...Rear guide wheel,
30... Rope, 32... Rear sealing material, 34... Center part, 36... Universal joint.

Claims (1)

[Claims] 1. A front guide wheel that is pulled by a rope body and touches the inner surface of the tube at two places in the front and rear directions, and an inner surface of the tube that is connected to the rear end of this front guide wheel through a universal joint located approximately at the center of the tube. a front sealing material made of an elastic body in contact with the front sealing material; a wheel provided near the rear outer periphery of the front sealing material to prevent excessive deformation of the sealing material; and a wheel connected to the rear of the front sealing material via a rope body. , a rear guide wheel in contact with the inner surface of the tube at two places in the front-rear direction, and a rear seal made of an elastic body in contact with the inner surface of the tube, connected to the rear end of the rear guide wheel through a universal joint located at a position passing approximately through the center of the tube. A back seal device for piping welding, characterized by having a material.