JPH02207874A - Method for lining inside surface of metallic pipe - Google Patents

Abstract

PURPOSE:To prevent the effluence of a fluid lining material by supplying the fluid lining material to the inside surface of a rotating metallic pipe and injecting air to the end of the metallic pipe before the lining material cures. CONSTITUTION:The fluid lining material is supplied into the rotating metallic pipe A. The fluid lining material is pushed back into the pipe and the effluence thereof is prevented by ejecting air pressure when the ejecting air is blown by an air nozzle C to the pipe end A'. The pushed back lining material serves as a dike wall to prevent the effluence of the fluid lining material in the inner part of the pipe. The effluence of the lining material at the pipe end is, therefore, prevented and the lining layer of a uniform thickness is formed if the ejection of the air is continued before the material cures. As a result, there is no need for labor in mounting jigs for preventing the effluence, etc., at all and the safety is assured in the lining method to be executed particularly at a high temp. as there are no changes for the operator to directly touch the pipe.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for lining the inner surface of a metal tube.

[Conventional technology]

Conventionally, cast iron pipes, steel pipes, etc. are provided with a corrosion-resistant lining layer made of mortar or synthetic resin material in order to prevent corrosion caused by internal fluids.

As a means for providing this corrosion-resistant lining layer, centrifugal molding is widely used because a layer of uniform thickness can be easily formed.

By the way, when lining is performed using the centrifugal molding method, after the fluid lining material is supplied into the rotating pipe and until it hardens, the lining material near the end of the pipe may flow out of the pipe. The thickness of the lining layer at the end portions may become thinner, making it impossible to achieve uniform lining.

For this reason, jigs to prevent the lining material from flowing out have traditionally been attached to the pipe ends, but these jigs are troublesome to attach and remove, especially when brazing with thermosetting resin. Heating to high temperatures forces the lining material to be made of metal for heat resistance, which increases the amount of ffi and makes it difficult to handle. There was a problem with great danger.

[Problem to be solved by the invention]

In view of the above, this invention does not require any attachment or detachment of jigs,
Furthermore, the object of this invention is to provide a method for lining the inner surface of a metal tube that can reliably prevent the lining material from flowing out at the end portions, thereby safely and reliably lining the inner surface.

[! ! Technology that led to solving the problem]

That is, in the method for lining the inner surface of a metal tube of the present invention, when a fluid lining material is supplied to the inner surface of a rotating metal tube and cured, the method includes supplying the fluid lining material to the inner surface of the metal tube and until the material is cured. The present invention is characterized in that air is injected into the end of the metal tube to prevent the lining material from flowing out.

[Effect]

When a flowable lining material is supplied into a rotating pipe,
If you blow jet air at the end of the pipe, the wind pressure of the jet air will cause
The flowable lining material is forced back into the tube and is prevented from flowing out.

In addition, the fluid lining material inside the pipe is pushed back by the lining material acting as a bank wall to prevent outflow.

Therefore, if the air injection is continued until the tube hardens, the lining material at the end of the tube will be prevented from flowing out, and a lining layer with a uniform thickness will be formed.

〔Example〕

Next, the present invention will be explained in detail.

Prepare a cast iron pipe with a length of 5 m and a diameter of 1 m, and as shown in Figures 1 and 2, place the pipe A on drive rollers B and B, heat the pipe to 330°C ± 20°C, and rotate it. Powder paint was supplied to the inside of the mold 9 and melted and adhered thereto. During the 30 to 40 seconds until the powder coating finishes adhering, air nozzles C...C were placed at an elevation angle of 60'' with respect to the end A', and air was sprayed. There was no resin leakage during this period.

〔effect〕

As explained above, this invention prevents the lining material from flowing out using the air pressure, so there is no need to attach a jig to prevent the lining material from flowing out, especially in the case of a lining method that uses high temperature treatment. It has the advantage of being safe because there is no direct contact with the pipe.

[Brief explanation of the drawing]

FIG. 1 is a side view of an embodiment of the invention, and FIG. 2 is a front view of the embodiment. ″′i2n

Claims (1)

[Claims] (1) In the case where a fluid lining material is supplied to the inner surface of a rotating metal tube and cured, air is injected to the end of the metal tube until the fluid lining material is supplied to the inner surface of the metal tube and hardens. A method for lining the inner surface of a metal tube, characterized in that the lining material is prevented from flowing out.