JPH01263029A - Rigid tube lining method for inner face of conduit with branch - Google Patents

Abstract

PURPOSE:To prevent water from leaking from a branch opening by forming an adhesive layer on a part of the outer periphery of a tube to be opposed to a branch, and allowing part of the outer periphery of the tube to adhere to the inner face of the periphery of a branch tube at the time of tube pressure expansion. CONSTITUTION:The part 1a of the outer periphery of a rigid tube 1 to be opposed to a conduit branch (b) is formed in advance with an adhesive layer 2. Steam is supplied through a conduit 4 and the first supply hole 5 of a front plug 3a into the tube 1. After the temperature of the outer surface of the tube 1 arrives at a softening point or higher of vinyl chloride resin and a melting point of the layer 2, compressed air is supplied as required into the tube 1 through a conduit 8 and a second supply hole 9 while the steam is continuously supplied. When the pressure in the tube 1 is raised, the tube 1 is expanded to be lined on the inner face of the conduit (a), thereby forming a hard tube lining. The periphery of the port b1 of the branch (b) adheres to the inner face of the conduit (a) through the layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hard tube lining method for the inner surface of a conduit with a branch section.

The conventional method for lining the inner surface of a pipeline is to insert a hard tube with a smaller diameter into the pipeline, and then expand the tube under pressure from the inside under heating and softening conditions to line the inner surface of the pipeline. A hard tube lining method has been proposed. The diameter of the hard tube lining formed by applying such heating and pressurizing expansion method is reduced by thermal contraction after the heating and pressurizing expansion, so a gap inevitably occurs between the hard tube lining and the pipe. Therefore, when a branch part is attached to a pipe line, when the branch part pipe port is opened, the gap at the branch part pipe port communicates with the inside of the pipe line, causing water leakage (or gas leakage).

The present invention has been made with the aim of eliminating such conventional problems.

Means for Solving the Problems The present invention provides a method for expanding a hard tube inserted into a conduit with a branch part under pressure from the inside under heating and softening conditions to line the inner surface of the conduit. An adhesive layer is formed in advance on the part of the surface facing the branch part, and when the tube is expanded under pressure, a part of the outer peripheral surface of the tube is attached to the pipe through the adhesive layer. This invention relates to a hard tube lining construction method for the inner surface of a pipe with a branch, which is characterized by adhering to the inner surface around the branch pipe opening.

EXAMPLE An example of the construction method of the present invention will be described below based on the accompanying drawings. In this example, the hard tube (1) was made of vinyl chloride resin, and the adhesive layer (2) was made of hot melt type. ) is made of thermoplastic synthetic resin such as polyethylene or polypropylene, and the adhesive layer (2) is made of thermoplastic synthetic resin such as polyethylene or polypropylene.
Instead of the hot-melt type, a two-component curing type can be used with the pot life adjusted appropriately.

FIG. 1 schematically shows the situation when the hard tube (1) is inserted into the conduit (a) with the branch part (b).

The hard tube (1) is made of vinyl chloride resin and has a circular cross section, and has an outer diameter (diameter) corresponding to about 50 to 90% of the inner diameter (diameter) of the pipe line (a). It is inserted into the pipe (a) using the difference in diameter between the pipe (a) and the pipe (a).

The pipe branch part (b) of the outer peripheral surface of the hard tube (1)
) An adhesive layer (2) is previously formed on the portion (1a) facing the portion (1a). The surface area of the adhesive layer (2) is the branch part (b
) It is slightly larger than the outer diameter of the pipe port and is bonded to the inner surface (al) of the pipe around the pipe port of the branch part (b).

The adhesive layer (2) is a hot-melt type, and the heating temperature of the hard tube (1) during lining construction is, for example, 90 to 1
A material that melts at a temperature of about 00°C is used.

FIG. 2 schematically shows the situation during the lining operation of the hard tube (1) for the conduit (a).
) are closed at both front and rear ends by a front plug (3a) and a rear plug (3b).

Now, when steam is supplied into the hard tube (1) through the conduit (4) and the first supply hole (5) of the front tube (3a) in the state shown in Figure 2, the steam flows inside the hard tube (1) from the front end. It flows toward the rear end, heating the tube (1) during this time, and is discharged to the outside through the exhaust hole (6) of the rear plug (1) and the exhaust pipe (7) connected thereto.

By steam heating, the temperature of the outer surface of the hard tube (1) becomes higher than the softening point of the vinyl chloride resin (approximately 80°C) and higher than the melting point of the hot melt adhesive layer (2), e.g.
After the temperature reaches about 5 to 100°C, compressed air is introduced into the tube (1) through the conduit (8) and the second supply hole (9) of the front tube (3a) connected to it while continuing to supply steam. If necessary, the tube (1) is supplied while being preheated to a temperature of about 80 to 100°C, and the pressure inside the tube (1) is adjusted from normal pressure to 0.3 kg/c.
1.0 to 1.5 kg/c from low pressure of ♂ (gauge pressure)
When the pressure is increased to around rl (gauge pressure), the hard tube (1
) is pressurized from the inside and expands, lining the inner surface of the conduit (a) as shown in FIGS. 2 and 3, effectively forming a hard tube lining.

After the hard tube (1) is expanded under pressure and the inner surface of the pipe (a) is lined, the supply of steam and the preheating of the compressed air are stopped while the inside of the tube (1) is kept under pressure. When the supply of compressed air at room temperature is continued, the hard tube (1) cools and solidifies, and thereafter maintains its lining state.

When the hard tube (1) is cooled and solidified, the tube (1)
Heat shrinkage occurs, and as shown in Figure 4, the pipe (a)
A gap (C) is created between the pipe opening (C) of the branch part (b).
Around bl), the tube (1) is glued to the inner surface of the conduit (a) via an adhesive layer (2). Since this adhesive layer (2) is simply formed around the tube opening (bl) of the branch part (b), it is hardly affected by the heat shrinkage of the tube (1), and the tube (1) To stably and reliably maintain an adhesive state regardless of heat shrinkage.

The pipe opening (bl) of the branch part (b) is
Although it is opened by applying conventional means, an adhesive layer (2) remains around the pipe opening (bl), and this adhesive layer (2)
acts as a seal around the tube opening (bl).

In the embodiment, a case is shown in which steam is used as a heating means for the hard tube, but a low electric heater or the like may also be used. In addition, as a pressurized expansion means, instead of pressurized fluid,
Functional pressurized inflation means such as a tube expansion pig or the like may also be applied. Further, the adhesive layer (2) may be formed only on the part facing the pipe opening (bl) of the branch part (b) as shown in the example, or it may have a width as shown in FIG. It may be formed over the entire length of the hard tube. In the former case, it is necessary to perform preliminary operations to check the location of the branch in two directions: the circumferential direction of the pipe and the pipe axial direction, but in the latter case, it is necessary to perform preliminary operations to check the location of the branch in two directions: the circumferential direction and the pipe axial direction. It would be very useful if you researched it.

Effects According to the construction method of the present invention, in the area around the pipe opening of the branch,
The adhesive layer that adheres the hard tube lining to the inner surface of the pipe acts as a seal around the branch mouth, eliminating the risk of water (or gas) leakage from the branch opening.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view schematically showing the state of the hard tube insertion process in the method of the present invention, and Fig. 2 is a longitudinal sectional view schematically showing the situation of the heating and pressurizing expansion process of the same hard tube. 3
The figure is a cross-sectional view of the branch portion in FIG. 2, FIG. 4 is a cross-sectional view showing the state when the hard tube is cooled and solidified, and FIG. 5 is a cross-sectional view showing the state when the branch port is opened. In the figure, (1) is a hard tube, and (2) is an adhesive layer. (that's all)

Claims (1)

[Claims] [1] When a hard tube inserted into a conduit with a branch part is expanded under pressure from the inside under heating and softening conditions to line the inner surface of the conduit, the outer peripheral surface of the tube facing the branch part is An adhesive layer is formed in advance on the part where the tube is to be attached, and when the tube is expanded under pressure, a part of the outer peripheral surface of the tube is bonded to the inner surface around the branch port of the pipe through the adhesive layer. A hard tube lining construction method for the inner surface of a conduit with a branch section.