JPS5915797A - Method of repairing damaged pipe - Google Patents

Abstract

PURPOSE:To improve the sealing function at the expanded pipe portions, by inserting a sleeve having annular projections into a damaged pipe having a sealing layer made of a soft material, and expanding opposite end portions of said sleeve. CONSTITUTION:By inserting a sleeve 12 having annular projections 15 into a damaged pipe 10 and expanding opposite end portions of the sleeve 12, the annular projections 15 of the sleeve 12 are forced into a sealing layer 14 formed over the inner surface of the pipe 10 with a soft metal, a chemical substance or the like and completely closes the leak passage between the damaged pipe 10 and the sleeve 12. Thus, since the fluid is sealed in the annular portion between the damaged pipe 10 and the sleeve 12, perfect sealing function can be obtained at the opposite expanded portions of the sleeve 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for repairing damaged pipes in 1F, especially damaged pipes of heat exchangers, etc., when damaged due to thinning or cracking due to some reason during use.

Heat exchanger tubes are exposed to harsh chemical environments, so they may suffer damage such as thinning or cracking. As a repair method, we can regenerate such damaged tubes while maintaining their functionality. The construction method shown in Figure 1 is known. In the figure, 1 is a pipe with a damaged part 6 occurring on the outer periphery, 2 is a sleeve (inner cylinder) inserted into the pipe 1 as shown in the figure, and the repair method involves repairing both ends of the sleeve 2. , by expanding the tube from the inner diameter side of the sleeve 2 using a tube expansion means such as hydraulic pressure or rollers, the damaged part 6 is sealed with the expanded tube portions at both ends of the sleeve 20;
This is a construction method to make the damaged pipe 1 reusable.

However, the conventional repair method described above simply
Since the joint is simply made by expanding both ends of the pipe and deforming the damaged pipe 1 into a bulge, there is a drawback that sufficient sealing performance at the bulge deformed portion cannot be expected.

The present invention has been proposed for the purpose of eliminating the drawbacks of the above-mentioned conventional methods and providing a method for repairing damaged pipes that can exhibit sufficient sealing performance. A sleeve having at least one annular projection on the outer circumferential surface of both ends is inserted into the damaged pipe formed by an appropriate means, and then both ends of the sleeve are expanded by an appropriate tube expansion means. This relates to a method for repairing damaged pipes.

Hereinafter, one aspect of the present invention will be explained in detail with reference to FIG. In the figure, reference numeral 10 denotes a damaged tube having a damaged portion 1, and the inner surface of the damaged tube 10 is coated with a metal or chemical substance softer than the sleeve material, which will be described later, using means such as plating or vapor deposition. The seal layer 14 is pre-crimped. Reference numeral 12 denotes a sleeve (inner cylinder) inserted into the damaged pipe 10, and the sleeve 12 is expanded at both ends by reducing pressure or by expanding means such as rollers, as in the conventional method, to remove the damaged pipe 1f.
At least one annular projection 15 (two in the illustrated example) having a sharp tip is protruded from the outer peripheral surface of the expanded tube portion of the sleeve 12 . When the sleeve 12 having such an annular protrusion 15 is inserted into the damaged tube 10 and both ends thereof are expanded, the annular protrusion 15 of the sleeve 12 is inserted into the damaged tube 10. It bites into the sealing layer 14 made of metal or chemical material to completely block the leak path between the damaged tube 10 and the sleeve 12. Therefore, the fluid that attempts to flow into the damaged tube 10 from the damaged portion 13 is sealed within the damaged tube 10 and the annulus portion of the sleeve 12, and the sealing function of the expanded tube portions at both ends of the sleeve 12 is completely maintained.

Note that the function of the sleeve 12 to mechanically hold the tube 10 through bulge deformation due to tube expansion is the same as in the conventional method.

In summary, the present invention involves inserting a sleeve having at least one annular protrusion on the outer circumferential surface of both ends into a damaged tube whose inner circumferential surface has a sealing layer made of a soft material formed by an appropriate means, and then The gist of the present invention is a method for repairing a damaged pipe characterized by expanding both ends of the sleeve with an appropriate pipe expanding means. One practical effect is that a method for repairing damaged pipes that provides a good sealing effect can be easily realized.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the conventional method, and FIG. 2 is a schematic explanatory diagram of the present invention.
: Soft seal layer, 15: Annular projection. Sub-Agent Patent Attorney Teru Ito (2 others) Figure 1

Claims (1)

[Claims] A sealing layer made of a soft material is formed on the inner circumferential surface of the damaged tube by an appropriate means, and at least one sealing layer is formed on the outer circumferential surface of both ends.
1. A method for repairing a damaged pipe, which comprises inserting a sleeve having two annular protrusions, and then expanding both ends of the sleeve using a suitable pipe expansion means.