JPS591070A - Internal sealing device for electric welded tube - Google Patents

Abstract

PURPOSE:To seal the weld point of an electric welded tube and the neighborhood thereof from the atmosphere by making internal sealing members for said tube expandable and contractable like an umbrella in a radial direction. CONSTITUTION:A cylinder 9 is actuated by a remote operation to slide a movable member 6 which expands or contracts a sealing member 4 like an umbrella. The members 4 provided before and behind the weld point 3 are expanded radially by the operation of the cylinders 9 to contact slidingly with the inside circumferential wall of a blank tube 1 by which the inside of the tube including the point 3 is shielded from the atmospheric air. The members 4 consisting of a rubber-like elastic material and do not damage the inside wall of the tube. Since the circumferential edges of the members 4 are bent in the advance direction of the tube 1, the inside of the tube is sealed positively against the minute fluctuation in the shape of the tube.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal sealing device for sealing a welding point and its vicinity from the atmosphere during the manufacture of an electric resistance welded pipe.

ERW pipe is a steel pipe that is welded by intensively heating both edges of a steel strip and press-welding them using heat generated by electrical resistance.When manufacturing this ERW pipe, high manganese materials and chromium-added materials are used. When welding in air, a defect called a penetrator occurs in the weld. One way to prevent this is to gas-shield the nutrient solution working area with an inert gas, such as argon gas or nitrogen gas.

This gas shielding method includes a method of directly spraying gas and a method of surrounding it with a shield box. but,
Since the former causes air to be trapped and the shielding is insufficient, the latter is generally adopted.

The conventional technology for sealing devices inside ERW pipes is as follows.

JP-A-52-2127.41r JP-A-56-128686
, Utsukai Sho 56-95485 is already known.

These conventional techniques will be briefly explained with reference to FIGS. 1 to 4.

Figure 1 is from Japanese Patent Application Laid-Open No. 52-2127. Figure 2 is JP-A-56-
128686. Figures 3 and 4 are from the 1980s.
485, each showing a pipe sealing device according to No. 485.
In each of these, a sealing member whose peripheral edge slidably contacts the inner circumferential wall of the tube is attached at a predetermined interval in the tube axis direction below the welding point 3 of the mandrel 2 extending inside the blank tube 1. The #P steel to be welded is a long piece wound into a coil, which is then unwound and the ends are successively connected by welding. However, % Japanese Patent Publication No. 52-212
In the pipe sealing device according to No. 7, the elastic body 4A is used as a sealing member, but since it cannot be expanded or contracted in the radial direction, the elastic body 4A may be damaged at the seam and the sealing function may deteriorate. Also.

Nor can it be applied to electric resistance welded pipes with different pipe diameters.

The same applies to the pipe sealing device according to Utility Model Application No. 56-95485 shown in FIG.

In the pipe sealing device according to JP-A-56-128686,
A wire brush 4B is used as a sealing member, but its airtightness is poor and a sufficient sealing effect is not achieved.

I can't do it. Moreover, the wire brush 4B is worn out and lacks durability. Furthermore, the wire brush 4B is broken during pipe making and gets caught in the welded part, causing quality defects.

In the pipe sealing device according to Utility Model Application No. 56-95485, tube 4C is used as a sealing member, but the friction resistance is 1.
If elasticity is required and elasticity is inappropriate, troubles such as breakage of the tube 4C and shear leakage will occur during pipe making.

The present invention was made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a tube inner surface sealing device that can be applied to electric resistance welded tubes having different diameters and can reliably seal the inside of the tube. .

According to the present invention, seal members whose peripheral edges are slidably in contact with the pipe inner circumferential wall are installed at predetermined intervals in the pipe axial direction of a mandrel extending inside the pipe, and when welding the ERW pipe, the seal members are used to secure the welding point and the welding point. In the pipe sealing device for sealing the vicinity from the atmosphere, each of the sealing members has a skirt shape that expands in diameter in the direction of relative movement with the pipe, and is expandable and contractible in an umbrella shape in the radial direction. An intracanal sealing device for a sewn tube is provided, with such an arrangement achieving the above objects.

The present invention will be described in detail below with reference to one drawing.

FIGS. 5 and 6 are views showing an embodiment of the pipe sealing device according to the present invention.

5 and 6, a seal whose peripheral edge is slidably in contact with the inner peripheral wall of the raw pipe 1 is located at a predetermined interval in the tube axis direction below the welding point 3 of the mandrel 2 extending inside the raw pipe 1. A member 4 is attached via a fixing member 5.

This sealing member 4 is configured in a skirt shape whose diameter increases rearward in the direction of relative movement with the raw pipe 1.

The fixed member 5 is connected via an expansion joint 7 to a movable member 6 that engages with the mandrel 2 and is slidable in the axial direction. The movable member 6 and the seal member 4 are connected by an appropriate number of links 8 provided radially, a cylinder 9 is connected to the movable member 6, and this cylinder 9 is fixed to the mandrel 2 by a cylinder mounting member 10. ing. The cylinder 9 can be operated by remote control, and the operation of the cylinder 9 causes the movable member 6 to slide, and the seal member 4 to expand and contract in an umbrella shape.

The body members 4 provided in front and behind the welding point 3 expand in the radial direction by the operation of the cylinder 9 and come into sliding contact with the inner circumferential wall of the blank tube 1, so that the inside of the tube including the welding point 4 is isolated from the outside air.

The sealing member 4 is made of a rubber-like elastic body.

The inner wall of the pipe is not damaged.

In addition, the sealing member 4 is attached in the direction of movement of the raw pipe 1 (Figs. 5 to 6).
The structure is inclined in the direction of the white arrow shown in the figure), so that the advance of the raw pipe 1 is not hindered by the seal member 4, and the amount of wear of the seal member 4 during pipe production, which would otherwise damage the periphery of the seal member 4, is minimized. Can be done. Since the seal member 4 is brought into sliding contact with the W# wall in the raw pipe 1 in an umbrella-like manner by an appropriate number of radially provided links, for example, 8, the peripheral edge of the seal member 4 is bent in the direction of movement of the raw pipe 1. As a result, the inside of the pipe is reliably sealed against slight variations in the pipe shape. .

Welding is carried out by moving the base pipe 1 formed from a steel band in the direction of the arrow, but when the seal member 4 approaches a seam (not shown), the seal member 4t is moved by operating the cylinder 9.
? If the seal member 4 is reduced in size so that the peripheral edge of the seal member comes into contact with the seam and exerts force, the seal member 4 will not be damaged.

A shield box 11 is fixed to the mandrel 2 and provided directly below the welding point 3 to fill the area around the welding point 3 with inert gas.

Reference numeral 12 is a squeeze roll for pressing the edge of the raw tube 1, and reference numeral 13 is a contact tip for power supply.

I can't help it.

In the above embodiment, two cylinders 9 are installed, but one cylinder may also be used in combination.

Furthermore, by using this device together with an inner and outer shield box, the shielding effect of the welding work area can be further enhanced.

As is clear from the above description, according to the present invention, the inside of the tube can be reliably sealed, and even electric resistance welded tubes having different diameters can be reliably sealed using this device.

[Brief explanation of drawings]

1 to 4 are cross-sectional views of a conventional pipe I-seal device, FIG. 5 is a cross-sectional view of an embodiment of the present invention, and FIG. 6 is a sectional view of a conventional pipe I seal device. ··Expansion joints. 8...Link, 9...Cylinder. Agent Tatsuyuki Unuma (and 2 others) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) Seal members whose peripheral edges are slidably in contact with the pipe inner circumferential wall are installed at predetermined intervals in the pipe axis direction of the mandrel extending inside the pipe, and when welding the ERW pipe, each seal member keeps the welding point and its vicinity from the atmosphere. In the sealing device for sealing the inside of a pipe, each of the sealing members is configured in a skirt shape whose diameter expands rearward in the direction of relative movement with the pipe, and is expandable and contractible in an umbrella shape in the radial direction. In-pipe sealing device. Q) The internal sealing device for an electric resistance welded pipe according to claim 1, wherein the sealing member is made of a rubber-like elastic body.