JPS5927195A - Repair of damaged tube - Google Patents

Abstract

PURPOSE:To repair a damaged tube easily and quickly by a method wherein a tapered sleeve is inserted into a damaged part in the locally damaged tube and both ends thereof are expanded to adhere the outer peripheral surfaces of both ends of the sleeve to the wall of the damaged tube with a pressure. CONSTITUTION:Upon repairing the damaged heat transmitting tube 11 of a heat exchanger, an expanding member 15 is inserted beforehand into the thinner part of the sleeve 13, the tip end screw part of a tension bar 17 is screwed into the center hole of the expanding member 15 and said tension bar 17 is pulled from the outside of the tube toward the thicker side of the sleeve 13 by a proper driving means such as a jack or the like, for example, to pull the expander 15 out of the sleeve 13. In this case, the tapered surface of the inner peripheral surface of the sleeve 13 is expanded forcibly by the tapered surface of the expanding member 15 and, whereby, the sealing between the outer peripheral surface of the sleeve 13 and the inner peripheral surface of the damaged tube 11 may be secured. On the other hand, lubricating oil in a groove 16 for the lubrication of the outer peripheral surface of the expanding member 15 serves to reduce a friction between the outer peripheral surface of the expanding member 15 and the inner peripheral surface of the sleeve 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for repairing a tube, such as a heat exchanger tube, in which a localized portion of damage has occurred due to some reason.

Conventionally, methods have been used to regenerate damaged pipes by inserting a sleeve into the damaged part of a pipe that has caused local damage, protecting the damaged part, and forming a new pressure boundary. In this case, it is necessary to sufficiently seal between the IJ-no and the inner wall of the pipe.

In order to ensure this seal, conventionally, as shown in Fig. 1, the upper and lower ends of the sleeve 2 inserted into the damaged pipe 1 are welded to provide a welded seal, or as shown in Fig. 2. A plurality of annular protrusions 4 are provided on the outer periphery of the upper and lower ends of the sleeve 2, and the upper and lower ends of the sleeve 2 are expanded by the expansion force of a mechanical roller or the like, and the space between the sleeve 2 and the wall of the damaged pipe 1 is expanded. A method of sealing by increasing the contact surface pressure has been taken. However, with the method shown in Figure 1, welding within the mainspring tube is extremely difficult and there are separation points, and with the method shown in Figure 2, in order to obtain a perfect sealing function, it is difficult to The tube must be expanded with a force stronger than that of a mechanical roller or the like, but there is currently no such powerful tube expansion means available.

In view of the above circumstances, the present invention has been proposed for the purpose of providing a method for repairing a damaged pipe that can exhibit a complete sealing function. A sleeve formed to have a thick wall and tapered surfaces on both ends of the inner peripheral surface is inserted into the damaged pipe so as to cover the damaged part from the inside, and then inserted into the thin wall of the sleeve. A cylindrical tube expanding member having an outer diameter as large as possible and having a tapered surface on its outer peripheral surface that matches the tapered surface of the sleeve is inserted into the thin walled portion of the sleeve, and then,
The tube expanding member is moved toward the thick side of the sleeve by an appropriate driving means to expand both ends of the sleeve, thereby crimping the outer peripheral surfaces of both ends of the sleeve to the wall of the damaged tube. The present invention relates to a method for repairing a damaged pipe characterized by the following.

The present invention will be specifically explained below with reference to FIGS. 6 and 4.

In FIG. 6, reference numeral 11 indicates a damaged tube, such as a heat transfer tube of a heat exchanger, which has a damaged portion (not shown), and both ends of the heat transfer tube 110 are attached to a tube plate 12. (However, only one end is shown in the figure.) 13 is a sleeve (metal inner cylinder) inserted into the heat exchanger tube 11 so as to cover the damaged part, and the sleeve 13 has a wall thickness at both ends. is formed in such a manner that it becomes slender in the axial direction from a thin wall portion to a thick wall portion in order, and a tapered surface having a taper angle α is formed on the inner circumferential surface portion of both ends.

Further, a plurality of rows of annular protrusions 14 are provided on the outer circumferential surface of both ends of the sleeve 13, and a tapered surface having a taper angle β is provided on the outer circumferential surface of the protrusions 14 as shown in FIG. It is being Reference numeral 15 denotes a cylindrical tube-expanding member having an outer diameter that can be inserted into the thin-walled portion of the sleeve 1, and whose outer peripheral surface is formed into a tapered surface that matches the tapered surface of the sleeve 13; The surface is provided with an annular groove 16 for lubricating oil. Reference numeral 17 indicates a pull rod whose threaded end portion can be screwed into the center hole of the tube expansion member 15.

In repairing the damaged pipe 11 by the method of the present invention,
When the wall thickness of both outer ends of the sleeve 160 is thick as shown in the illustrated example, the tube expansion member 1 is inserted into the thin wall portion of the pre-swaged sleeve 16.
5 is inserted, and the threaded end of the pull rod 17 is screwed into the center hole of the tube expansion part 15, and the pull rod 17 is moved from outside the tube by an appropriate driving means such as a jack to adjust the thickness of the sleeve 1. Pull it toward the meat part side and slide the tube expanding member 15.
Pull out J-No1ro. At this time, the tapered surface of the inner circumference of the sleeve 16 is forcibly expanded by the tapered surface of the tube expansion member 15, and the thick part of the sleeve 13 is fluid-tightly pressed against the inner circumferential wall of the damaged tube 11. A seal is ensured between the outer circumferential surface of the pipe 13 and the inner circumferential surface of the damaged tube 11. Furthermore, the lubricating oil in the lubricating oil groove 16 on the outer circumferential surface of the tube expanding member 15 is distributed between the outer circumferential surface of the tube expanding section control 5 and the sleeve 13.
Helps reduce friction between the inner peripheral surfaces. Furthermore, in the illustrated example, since the outer circumferential surface of the annular protrusion 14 provided on the outer circumferential surface of the end of the sleeve 13 is formed into a tapered surface with a taper angle α, the outer circumferential surface of the end of the sleeve 16 and tube 11
This helps to ensure a better sealing effect between the inner circumferential surface of the

If the same operation as described above is performed on the other end of the sleeve 16, a complete seal will be formed between the outer peripheral surface of both ends of the sleeve 13 and the inner peripheral surface of the damaged tube 11. tube 1
1 is played.

The illustrated example uses a sleeve 13 whose wall thickness accumulates in the axial direction from both ends and becomes thinner as it goes inward. When using a sleeve, the cylindrical tube expanding member may be pushed in from outside the tube.

In summary, the present invention provides a sleeve that is formed so that the wall thickness of both ends decreases in the axial direction from a thin wall part to a thick wall part, and that has a tapered surface formed on the inner peripheral surface of both ends, inside a damaged pipe. A cylindrical expanded pipe having an outer diameter that can be inserted into the thin walled part of the sleeve after being inserted to cover the damaged part from the inside, and having a tapered surface on the outer peripheral surface that matches the tapered surface of the sleeve. The member is inserted into the thin-walled portion of the sleeve, and then the tube-expanding member is moved toward the thick-walled side of the sleeve by an appropriate driving means to expand both ends of the sleeve. Since the gist of the present invention is a method for repairing a damaged pipe characterized by crimping the outer circumferential surface of the damaged pipe to the pipe wall of the damaged pipe, the present invention can repair a damaged pipe with a locally damaged part. The practical effect is that repairs can be carried out easily, reliably, and quickly.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are schematic explanatory diagrams of the conventional method, respectively;
6 and 4 are schematic explanatory diagrams of the method of the present invention, and FIG.
The figure is a longitudinal sectional view of the main part, and FIG. 4 is an enlarged view of section A in FIG. 3. 11: Damaged pipe, 12: Tube plate, 1 Ronisleeve,
14: Annular projection, 15: Cylindrical tube expansion member, 16;
Groove for lubricating oil, 17: Tension rod, α, β; Taper angle. One meeting. Sub-Agent Patent Attorney Teru Ito 5 (2 others) Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] Is the wall thickness at both ends in the axial direction? After inserting a sleeve, which is formed from a thin wall part to a thick wall part in sequence and has a tapered surface on the inner circumferential surface of both ends, into the damaged pipe so as to cover the damaged part from the inside. It has an outer diameter that allows it to be inserted into the thin wall portion of the sleeve. and, inserting a cylindrical tube-expanding member having an outer peripheral surface with a tapered surface that matches the tapered surface of the sleeve into the thin-walled portion of the sleeve, and then driving the tube-expanding member with an appropriate driving means, A method for repairing a damaged pipe, which comprises moving the sleeve toward the thick side and expanding both ends of the sleeve, thereby crimping the outer circumferential surface of both ends of the sleeve to the wall of the damaged pipe.