JPH0315072B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for lining pipes including bent portions.

Conventional technology and its problems Conventionally, as a method for lining pipes such as water pipes, a lining pipe body with a diameter one step smaller than the diameter of the pipe is inserted into the pipe, and then a lining pipe body is inserted between the inner and outer pipes. A so-called pipe-in-pipe construction method has been proposed, in which the pipe body is lined and fixed inside the pipe by filling a bonding material such as mortar inside the pipe. If there were any defects, it would be difficult to insert the tube and it could not be carried out.

In addition, a tube lining method has been proposed in which a flexible elastic tube with the same diameter as the pipe is inserted into the pipe and integrated with the inner surface of the pipe by applying an adhesive. However, since the tube does not have shape retention,
If there is poor adhesion in even a part, peeling will progress gradually and the lining will not be able to maintain its condition.In addition, in bent pipe parts, the difference in curvature between the outer and inner peripheries will cause the inner periphery to peel. There were problems with the construction reliability, such as the tube becoming loose and wrinkled, causing peeling.

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

Means for Solving the Problems When lining a pipe line including a bent portion with a tube made of thermoplastic synthetic resin, the present invention provides for the tube to have a cylindrical shape, shape retention, and flexibility, and furthermore to After flattening this tube so that its outer diameter is smaller than the diameter of the pipe line,
Utilizing the bendability obtained from the flat shape and the above-mentioned flexibility, it is inserted over the entire length of the pipe while passing through the curved part of the pipe, and then moved inside the tube from the starting end toward the terminal end. The tube is expanded into the pipe by using a heat pig that adds a circulation hole for expanding the tube, and pressurized air that passes through the circulation hole of the pig while being heated and is supplied to the tube in front of the pig. A lining for a conduit including a bent portion, which is characterized in that it gradually expands in the radial direction from the starting end toward the terminal end, and as the expansion progresses, a shape-retaining lining made of the tube is formed on the inner surface of the conduit. Concerning construction methods.

Embodiment An embodiment of the present invention will be described below based on the accompanying drawings.

In the construction method of the present invention, a thermoplastic synthetic resin tube 1 is used as the lining material. There are no particular restrictions on the thermoplastic synthetic resin, and it is usually selected from among polyvinyl chloride, polyethylene, polypropylene, etc., but for applications where heat resistance and chemical resistance are particularly required, polyethylene is used. Ethylene fluoride (trade name: Teflon) is suitable.

_The above-mentioned tube 1 has a cylindrical shape, shape retention, and a flattened state.
It is necessary to have a degree of flexibility that does not interfere with insertion into bends, etc.), and such shape retention and flexibility are determined by the type of synthetic resin, degree of polymerization, and polymerization method (polyethylene ), by appropriately selecting the amount of plasticity added (polyvinyl chloride), etc.

The tube 1 has a diameter corresponding to 50 to 70% of the diameter of the conduit a, and if it remains cylindrical, it will be difficult to insert it into the bent part _a1 of the conduit a due to shape retention. The pipe is flattened so that its outer diameter is smaller than the diameter of the pipe a.

Fig. 1 shows the flattening process in the order of steps, where the cylindrical tube 1 is first pressed and deformed in the vertical direction
Next, it is pressed and deformed from the left and right directions to form a flat shape. The degree of this flattening should be as small as possible within the range that makes the outer diameter smaller than the above-mentioned pipe and provides flexibility. By keeping the degree of flattening as small as possible in this way, it is easy to restore the cylindrical shape. becomes. This flattening process can be performed with the tube 1 heated and softened if necessary, but in consideration of the ability to restore the tube to a cylindrical shape, it is preferable to process it at room temperature as much as possible.

After the tube 1 is flattened, it is inserted into the conduit a, as shown in FIG. tube 1
Due to the flexibility obtained from the flat shape and flexibility,
It can easily pass through the bend _a1 of the conduit a, and can be inserted over the entire length of the conduit a while passing through the bend _a1 . In FIG. 2, 2 is a pulling rope, and 3 is a winch for winding up the pulling rope.

Following the insertion of tube 1 into conduit a,
Preparation for lining the tube is performed as shown in the figure. In this preparatory work, the diameter of the starting end side of the tube 1 to be inserted into the pipeline is expanded by applying appropriate means, and a heating pig 4 for expanding the tube diameter is installed in this expanded diameter section 1a. A small-diameter ball 6 for preliminary expansion is connected to the pig 4 via a flexible member 5, and communication holes 4a and 6a are formed in the pig 4 and the ball 6, respectively, to penetrate in the tube axis direction. ing. Furthermore, plugs 7 and 8 are installed at the beginning and end of the tube 1.
The start end plug 7 has a supply port 11 for supplying pressurized air from a supply source such as a compressor 9 into the tube 1 through a conduit 10 with an on-off valve 10a, and the end plug 8 has an exhaust port. 12 are formed respectively, and an on-off valve 13 is provided at the exhaust port 12.
An exhaust pipe 13 with a is connected. tube 1
The pressure of the pressurized air inside can be adjusted by adjusting the opening degree of the on-off valves 10a and 13a.

The heating vig 4 has a built-in electric heater 4b, and is heated by the heater 4b so that the surface temperature is above the softening point of the tube 1 and below the melting point.
The power cord 4b ₁ of the heater 4b freely passes through the starting end plug 7 and is connected to a power source (not shown). In the other figures, 14 is a towing rope, and 15 is a winding winch.

When pressurized air is supplied into the tube 1 in the state shown in FIG.
It is heated as it passes through a, becomes heated and pressurized air, and flows into the tube 1 on the front side of the pig 4,
While heating and pressurizing the tube 1, the exhaust port 1 of the terminal plug 8 is opened.
2, the gas is discharged through an exhaust pipe 13 connected thereto. The opening degree of the valve 13a on the exhaust pipe 13 is adjusted so that the pressure inside the tube 1 is maintained at a predetermined pressure, for example, about 0.5 to 5.0 kg/cm ² .

The tube 1 on the front side of the heating pig 4 is preheated by the heated and pressurized air and at the same time tends to restore its shape to a cylindrical shape, and the degree of this preheating and restoration tendency is as follows:
The closer you get to the heating pig 4, the larger it becomes; for example, the heating pig 4
At the _P1 position, which is close to P1, the shape is restored to a substantially cylindrical shape as shown in FIG. 4, but at the _P2 position, which is far away, the flattened state is maintained as shown in FIG.
The pressurized air is supplied to the conduit 10 as shown in Figure 3-a.
The tube 1 is heated by the heater 16 provided for
It may also be supplied inside.

In this way, while preheating and restoring the shape of the tube 1 on the front side of the heating pig 4 using pressurized air, the tow rope 14 is operated to remove the pig 4.
As shown in FIG.
As the pig 4 moves, the tube 1 is heated and softened and expanded in the radial direction, and this heating softening and expansion occurs quickly because the tube 1 has been preheated with pressurized air and restored to its cylindrical shape. is carried out smoothly. On the other hand, tube 1 after diameter expansion
is pressed against the inner surface of the pipe a by the pressure of the pressurized air, and maintains this pressed state thereafter. If the heating pig 4 is equipped with a small diameter ball 6 as shown in the figure, the ball 6 will preliminarily expand the tube 1.
Although the burden upon expansion of the heating pig 4 is reduced accordingly, provision of such a ball 6 may be omitted.

By continuing the supply of pressurized air into the tube 1 and the movement of the heating pig 4 within the tube 1, the lining of the tube 1' can be applied over the entire length of the conduit a as shown in FIG. Can be done. Since the lined tube 1' has shape retention,
To stably and reliably maintain the lining condition thereafter without applying adhesive or the like. Moreover, the tube 1' lined in conduit a is expanded by 50 to 70% of the diameter of conduit a, and therefore, not only the straight part of conduit a but also the curved part _a1 , especially the curvature Even on the inner circumferential side where the radius is small, no wrinkles occur at all, and a smooth finished surface can be obtained over the entire length of the pipe a. If the diameter of tube 1 exceeds 70% of the diameter of conduit a, wrinkles tend to occur in the lining on the inner circumferential side of bent part _a1 , and if it is less than 50%, tube 1 expands. Both of these methods are undesirable, since the rate becomes considerably large and causes problems such as uneven expansion and the occurrence of fissures.

In the present invention, the wall thickness of the tube 1 used as the lining material is reduced by expansion, so a wall thickness that can maintain its shape without any problem even when the wall thickness is reduced is used. is selected from a range of about 1.0 to 10.0 mm depending on the diameter, expansion ratio, material, etc.

Also, as the heating pig 4, instead of a spherical one,
For example, it is possible to use a truncated conical shape as shown in FIG. 8, which has a hemispherical portion 4d at the front end via a stepped portion 4c.

Effects According to the construction method of the present invention, by flattening the lining tube 1, it is possible to ensure insertion into the curved part _a1 of the pipe line a, and the diameter is 50 to 70 mm smaller than the diameter of the pipe line a.
%, it is possible to apply a smooth lining over the entire length of the pipe a including the bent part _a1 without causing troubles such as cracks, and furthermore, due to the shape retention property, after the tube is lined, Tube linings of good quality and properties can be applied to conduits including curved parts, such that the lining condition can be maintained stably and reliably for a long time.

Furthermore, since the tube 1 is preheated and restored from a flat shape to a cylindrical shape, it is heated and softened and expanded by the heating pig 4, so that such heating softening and expansion are carried out smoothly, increasing the lining construction speed and work efficiency. can be improved.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an example of flattening of the lining tube used in the construction method of the present invention, Figure 2 is a sectional view showing how the tube is inserted into the pipeline, and Figure 3 is lining construction. Figure 3-a is a cross-sectional view of the main part showing an example of its modification, Figures 4 and 5 are cross-sectional views of positions P ₁ and P ₂ in Figure 3, Figure 6 FIG. 7 is a cross-sectional view showing the state of the lining, and FIG. 8 is a cross-sectional view showing an example of the heating pig. In the figure, 1 is a lining tube, 1' is a tube lined with a conduit, 2 is a lead-in rope, and 3 is a tube for lining the pipe.
is a winch, 4 is a heating pig, 5 is a connecting member, 6 is a ball, 7 and 8 are plugs, 9 is a compressor, 10
1 is a conduit, 11 is a supply port, and 12 is an exhaust port.

Claims (1)

[Claims] 1. When lining a pipe line including a bend with a thermoplastic synthetic resin tube, the tube must have a cylindrical shape, shape retention, and flexibility, and a diameter corresponding to 50 to 70% of the diameter of the pipe line. After flattening this tube so that its outer diameter is smaller than the diameter of the conduit, the tube is made into a flat shape by utilizing the bendability obtained from the flat shape and the flexibility. The heating pig is inserted along the entire length of the pipe while passing through the bent portion of the tube, and then moved inside the tube from the starting end toward the terminal end. The pipe is gradually expanded in the radial direction from the starting end toward the terminal end within the tube pipe line, using pressurized air that passes through the pipe and is supplied into the tube in front of the pig, and as this expansion progresses, the pipe line A method for lining a conduit including a curved portion, characterized by forming a shape-retaining lining made of the tubes on the inner surface.