JPH07132566A - Method for forming pipeline of laid pipe made of synthetic resin - Google Patents

Abstract

PURPOSE:To make a resin pipe into a specified crosssectional shape without generating uneven thickness and ununiform deformation by a method wherein a hard or semi-hard thermoplastic resin pipe with a flat crosssection wound on a drum is arranged along a face for laying while it is heated and a pig with a specified shape is inserted from one end of a resin pipe to expand and deform the pipe. CONSTITUTION:A resin pipe extruded from an extruder is wound on a drum while it is heated. This resin pipe 1 is arranged along a face for laying while it is expanded and deformed in some extent by pressing a heated steam therein. Then, a drawing member 50 is inserted into the resin pipe 1 and is pulled to move a pig 60 in the resin pipe 1. The pig consists of a dense material with a round crosssection and a heating medium feeding hose 66 and a cooling medium feeding hose 67 are connected with the rear face and a plurality of heating medium ejecting holes 62 are provided on the apex face and a plurality of cooling medium ejecting holes are provided on the rear face. Then, when the pig 60 is moved in the resin pipe 1 in the longitudinal direction while a heating medium and a cooling medium are ejected, the crosssection of the resin pipe 1 is deformed into a round shape and the shape is held by cooling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a conduit for water and sewer pipes and various other types of laying pipes, and more particularly to a method for forming a synthetic resin laying pipe using a resin pipe made of hard or semi-rigid synthetic resin. .

[0002]

2. Description of the Related Art Conventionally, in the case of newly constructing the above-mentioned pipeline, a large number of short straight tubular pipes having a circular cross section with a length of about 2 to 5.5 m and made of fume pipes or rigid or semi-rigid synthetic resin pipes are used. There has been a method of preparing and laying the pipes in the pipe laying groove while sequentially connecting the ends of these pipes.

However, in such a multi-connection system of short pipes, it is troublesome to process the end connection portion of each resin pipe, and it is complicated because a connection work is required at the time of forming a pipe line. Since the number of connections increases as it becomes a pipeline,
The connection work requires a long time, which in turn lengthens the construction period, and there are drawbacks such that the pipe cannot be bent smoothly.

Therefore, as a method of laying a pipeline which can eliminate such drawbacks, the applicant of the present invention described above, while heating and softening a thermoplastic hard or semi-rigid synthetic resin tube having a flat cross section wound around a drum, while A step of unwinding from the drum and arranging along the laying surface, and a step of bulging and deforming into a circular cross section by internally pressurizing the softened resin pipe by steam pressure feeding etc. while arranging on the laying surface or after arranging We have proposed a method for forming a conduit for a synthetic resin laying pipe, which is characterized by carrying out the above (Japanese Patent Application No. 5-41515).

According to the method for forming a pipeline according to this proposal, the number of connection points can be markedly reduced or the connection work itself can be eliminated. Therefore, the lengthening of the construction period due to the complexity of the connection work is eliminated. In addition, it is possible to dramatically reduce the risk of liquid leakage and liquid intrusion from the connection part, and to lay a laying pipe that functions reliably and stably for a long time in a short time. With the length of the resin pipe wound on the drum, it can be transported to the installation site.
In addition to being efficient in transportation, it is possible to transport a large amount of resin pipes in a short time, and because the resin pipe wound on the drum is placed on the laying surface while heating and softening it, not only linear laying but also bending laying is possible. It is easy to use, and therefore, the practically extremely useful and great advantage can be enjoyed, that is, the freedom to select the conduit can be significantly increased.

[0006]

However, it was found in the subsequent research that the method according to the above-mentioned proposal may have the following new drawbacks.

That is, when the vapor pressure feeding method is used as the internal pressurizing means of the resin pipe, it is necessary to raise the vapor pressure to some extent in order to bulge and deform the resin pipe at a time along the length direction. On the other hand, since the lower surface of the laid resin pipe is in contact with and supported by the laid surface, the upper portion of the cross section is relatively easily deformed. When the high-pressure internal steam is introduced, the upper portion of the resin pipe is preferentially deformed to have a thin wall, which tends to cause uneven thickness.

In addition, since the thin portion, which is inevitably produced in manufacturing, preferentially bulges and deforms when the internal pressure is increased,
There is a drawback that a uniform deformed cross section cannot be obtained.

In addition, not only in the cross section of the resin pipe, but especially in the case of long construction, temperature unevenness occurs in the internal steam in the lengthwise direction of the pipe, so that the pipe on the side opposite to the steam pumping side pipe end is generated. It was difficult to obtain uniform deformation at the edges.

In addition, when the pipe is deformed under pressure by steam pressure feeding, the entire pipe is also cooled after the deformation. However, in a long construction, there is a large variation in the contraction rate during cooling, so However, it also had the drawback of being easily deformed.

If the uneven thickness or non-uniform deformation as described above occurs, the pressure loss of the fluid flowing inside the pipe after laying increases or the flow becomes non-uniform, so that the regular performance of the pipe cannot be exhibited. There was

The present invention has been made in view of the above technical background, in which a resin pipe rewound from a drum is
An object of the present invention is to provide a pipeline forming method capable of expanding and deforming into a desired cross-sectional shape without causing uneven thickness or uneven deformation.

[0013]

In order to achieve the above object, the present invention does not bulge and deform a resin pipe by steam pressurization as in the prior proposal, but inserts a pig inside thereof. , To expand the pipe.

More specifically, more specifically, a thermoplastic hard or semi-rigid synthetic resin tube (1) having a flat cross section wound around a drum (7) is wound from the drum (7) while being heated and softened. The step of returning and arranging along the laying surface (30), while arranging on the laying surface (30) or after arranging, insert a pig of a predetermined cross-sectional shape from one end into the inside of the resin pipe (1). And a step of expanding and deforming the resin pipe (1) into a corresponding cross-sectional shape of a pig, which is a gist of a method for forming a conduit line of a synthetic resin laying pipe.

A method for forming a conduit for a synthetic resin laying pipe according to the present invention will be described below in more detail with reference to the accompanying drawings.

As a preferred example of the hard or semi-rigid thermoplastic resin forming the resin tube, a hard vinyl chloride resin can be cited. The reason why the resin pipe is wound around the drum in a flat cross section is as follows.

That is, if the winding diameter is small with a circular cross section, the local bending stress is likely to concentrate on a part of the tube wall, and in order to avoid this, the winding diameter must be increased.
Moreover, since the winding volume increases with each winding,
After all, it cannot be wound into a long one. Therefore, by winding the resin tube in a flat cross-section so that its minor axis direction matches the winding diameter direction, it is possible to wind with a small winding diameter and This enables long winding while suppressing an increase in bulk.

As shown in FIG. 2 (a), the resin pipe (1) is flattened so that the internal hollow portion (1a) has an oval cross section, or at least as shown in FIG. 2 (b). In addition, it is desirable that the both ends in the width direction are flattened so that the hollow portions (1a) are present. That is, as shown in FIG. 3, when the entire inner surface of the cross section of the resin pipe is flattened so as to be in close contact with the resin pipe and the hollow portion is partially blocked in the length direction of the resin pipe, At the time of softening deformation by introducing the heat medium inside, not only the softening deformation takes time due to the obstruction of the flow of the heat medium, but also the heat medium does not flow sufficiently and uniformly in the tube, resulting in uneven heating and softening. As a result, uniform deformation of the entire pipe may be difficult. Therefore, as shown in FIG. 2 (a) or (b), the resin pipe (1) is flattened in a state where the internal hollow portion (1a) is present to promote uniform and smooth circulation of the heat medium and pressurize and swell. It is good to ensure uniform deformation over time. Of course, as shown in FIG. 2 (c), it may be flattened so that the hollow portion (1a) also exists in the widthwise middle portion. However, if the length L1 (shown in FIG. 2B) of the inner hollow portion (1a) in the transverse direction in the minor axis direction is too large, the cross-section becomes close to a circular shape, and the above-mentioned problems during winding are likely to occur. Therefore, it is preferable to flatten the resin pipe (1) so that the length L1 in the minor axis direction is about 5 to 25 mm.

The method for winding the resin pipe (1) in a flat cross section is not particularly limited, but the following method is preferable. That is, as shown in FIG. 1, a resin pipe (3) having a circular cross section is extruded from an extruder (2), cooled and solidified by a cooling device (4), and then sent out by a delivery device (5). Further, the resin pipe (3) is guided to the reheating device (6) and heated from the outside to a predetermined softening temperature or higher by supplying steam or the like, and then wound around the drum (7) in a roll shape while maintaining the heat softened state. take. At this time, it is desirable that the reheating device (6) be connected to the resin pipe (3).
When the tip of the tube comes out, a plug body (9) made of rubber or the like having a hose (8) attached to the tip opening is tightly fitted to close the tube end. This hose (8)
Is used for introducing a heat medium or cooling air described later. Then, using the plug body (9), FIG.
As shown in (c), the tip of the resin tube (3) is fixed to the winding drum portion of the drum (7), and the drum is rotated. By rotating the drum (7) at a variable speed corresponding to the feeding speed of the resin pipe (3), the resin pipe (3) is wound around the drum body in a multi-stage stacking state. Then, a predetermined pressing force is applied to the resin pipe (3) having a circular cross section when the resin pipe (3) is wound around the drum body to form the resin pipe (1) having a flat cross section.

The drum (7) wound with the resin pipe (1) is moved to a laying place by a truck or the like and then laid. Specifically, first, a sealing plug (10) as shown in FIG. 4 is attached to the tube opening at the winding end portion. The sealing plug (10) may be attached in advance after winding the resin tube (1) around the drum (7). The sealing plug (10) is a thick disk-shaped plug body (11) made of hard rubber.
And a cylindrical body (12) made of aluminum or an aluminum alloy arranged on the front side of the stopper body, and the tip of the cylindrical body (12) has a reduced diameter. Also, the outer diameter R of the plug body (11)
Is set to +0 to 20 mm with respect to the inner diameter of the resin pipe before flattening, while the outer diameter R ′ of the tip end portion of the tubular body (12) is −0 to 2
It is set to 0 mm. Further, a plurality of retaining projections (13) along the outer periphery are provided on the outer peripheral surface of the plug body (11), and O-rings (14) for sealing are arranged on both outer sides of the protrusions. Has been done. In addition, at the center of the plug body (11), a closable introduction hole (15) for allowing the passage of steam or refrigerant is provided in an axially penetrating state.

The sealing plug (10) is forcibly pushed into the pipe with the tubular body (12) and the plug body (11) in a state where the pipe mouth of the resin pipe (1) is locally softened by heating with a burner or the like. After that,
Tighten the outer circumference of the stopper body (11) from the outside of the pipe with the band band (16). In the attached state, the band band (16) tightly adheres the inner peripheral surface of the pipe to the plug body (11) and the cylindrical body (12) in a liquid-tight state, and the O-ring (14) further prevents leakage and Protrusions on outer peripheral surface of body (13)
The inner surface of the pipe is difficult to fit and the sealing plug (10) is prevented from coming off. In addition, it is preferable to use a band having a portion that can be connected to a fixed object such as a manhole as the band (16).

After attaching the sealing plug (10), vapor as a heating medium is pumped into the resin tube (1) from the hose (8) attached to the winding start end of the resin tube (1) to At the same time as heating and softening the pipe (1) from the inside, while bulging and deforming from the inside to some extent by the vapor pressure, as shown in FIG.
The truck (20) is advanced in the laying direction, and the resin pipe (1) is gradually rewound from the drum (7). This heating and swelling is performed in order to facilitate the rewinding of the resin pipe (1), and therefore may be performed to such an extent that a piano wire or the like described later can be inserted therethrough. For this reason, the vapor pressure is 0.
It is better to set it to about 4 to 1.2 kg / cm ² . Further, as long as the resin pipe (1) can be softened by heating, the mouth of the resin pipe does not necessarily need to be sealed.

In this way, the rewound resin pipe (1) is arranged along the laying surface (30) as the truck (20) advances. As in the conventional case, the groove (31) is previously cut in the laying place, and the resin pipe (1) is cut along the groove (31).
Is generally arranged.

Thus, the unwound resin pipe (1) may have a winding curl. In that case, the resin pipe (1) is laid on the laying surface (30) in a state where it is bent or bent, and the laying surface is It is not possible to obtain a laying condition that is straight along. Therefore, as shown in FIG. 5, it is recommended to use a pipe axis restricting jig (40) for fitting the installation surface (30) in a straight line.

FIG. 9 is an enlarged view of an example of the tube axis regulating jig (40) in which the lower regulating jig (41) and the upper regulating jig (42) are combined. By being
It is shaped like a wedge, with the top facing down and the bottom facing up. And the lower tube axis regulation jig (41)
Is formed with a semi-circular recess (41a) along the outer periphery of the resin pipe (1) at the center of its upper surface, and the upper pipe axis regulating jig (42) is also provided at the center of its lower surface. A semicircular recess (42a) is formed along the outer periphery of the resin pipe (1). When the upper and lower pipe axis regulating jigs (41) (42) are combined, a resin pipe insertion hole (43) is formed in the central portion so as to penetrate in the thickness direction. Further, as shown in FIG. 9 (b), both upper end edges (41b) (41b) of the recessed portion (41a) of the lower tube axis regulating jig (41) and the upper tube (not shown) are shown. The lower end edges of both sides of the recessed portion (42a) of the shaft regulating jig (42) are chamfered to prevent damage to the surface of the resin pipe due to contact with these edge portions.

The pipe axis regulating jig (40) is used as follows. That is, the lower pipe axis regulating jig (41) is arranged along the laying surface (30) at predetermined intervals by inserting the lower portion thereof into the ground. At this time, as shown in FIG. 11A, when the laying surface (30) is a uniform surface that does not require leveling, the lowest position of the recess (41a) is the laying surface (30), that is, the groove surface. Insert the jig into the ground until it reaches the same level, and set the groove surface and the recessed part (41) in the entire length direction of the resin pipe (1).
It should be supported by the bottom of a). On the other hand, as shown in FIG. 11 (b), when unevenness is present on the laying surface (30) and level adjustment is required, the lowest position of the recess (41a) should be at the same level.
The length of each jig (41) inserted into the ground may be adjusted.

Next, the rewound resin pipe (1) is arranged so as to pass over the recessed portions (41a) of the pipe axis regulating jigs (41).

After the unwinding of the resin pipe (1), the sealing plugs (9) and (10) at both ends are removed, and if necessary, the pipe ends are connected and fixed to a fixed object such as a manhole. Then, after inserting the piano wire or the like from the one end pipe opening of the resin pipe (1) to the other end pipe mouth, the piano wire is connected with a pulling member (50) such as a wire and pulled back to pull the pulling member (50) into the resin pipe. Insert into (1). Then, the end of the pulling member (50) is connected to the pig (60), and the pulling member (50) is pulled from the other end side to move the pig (60) into the resin pipe.

As shown in FIG. 6, such a pig is made of a solid material having a circular cross section formed of a metal such as an aluminum alloy, and a traction member is connected to the central portion of its spherical tip surface. A connecting portion (61) is formed for this purpose. The pig (60) plays a role of forcibly expanding the resin pipe (1) by forcibly inserting the flat resin pipe (1) inside, and for this reason, the outside of the pig (60). The diameter is 0 to 1 with respect to the inner diameter of the resin pipe before flattening.
0% (preferably 0 to 3%) is set large,
The length is set to about 200 to 400 mm. Further, a plurality of heating medium ejection ports (62) are radially outwardly arranged at intervals in the circumferential direction at the radial middle portion of the tip surface of the pig (60), and the rear surface of the pig (60) is also formed. A plurality of cooling medium jets (63) at the middle position in the radial direction
Open radially outward at intervals in the circumferential direction.
Further, a heating medium introducing hole (64) and a cooling medium introducing hole (65) are opened in the central portion of the rear surface of the pig, and the heating medium is supplied to the heating medium introducing hole (64) and the cooling medium introducing hole (65). The hose (66) and the cooling medium supply hose (67) are connected to each other. Moreover, the heating medium introduction hole (64) and the heating medium jet port (62) are connected to each other through the heating medium flow passage (6
8), and the cooling medium introduction hole (65) and the cooling medium jet port (63) are communicated with each other through an annular cooling medium flow passage (69). Therefore, the heating medium supplied from the heating medium supply hose (66) to the introduction hole (64) is ejected radially outward from the ejection port (62) through the flow passage (68) in the traveling direction, and the cooling medium. The cooling medium supplied from the supply hose (67) to the introduction hole (65) is ejected radially outward from the ejection port (63) through the flow passage (69) in the traveling direction. The heating medium may be steam, and the cooling medium may be water or air.

Then, while jetting the heating medium and the cooling medium, as shown in FIG. 7, the pig (60) is pulled to move the resin pipe (1) in the longitudinal direction. The jetted heating medium collides with the inner surface of the pipe in the forward direction, and the pipe wall is heated and softened. Therefore, as the pig (60) advances, the softened portion is forcibly and easily expanded in the radial direction until the softened portion conforms to the cross-sectional shape of the pig. On the other hand, the cooling medium ejected from the rear surface of the pig (60) collides with the inner surface of the resin pipe which has been subjected to the forced deformation force by the pig, and the pipe wall is cooled and shaped. In this way, as the pig (60) advances, the resin pipe (1) gradually and continuously deforms into a circular cross section from the one end side, and is cooled and shaped.

In this way, the pipe expansion by the pig (60) is carried out. However, if the twisting or bending due to the winding of the resin pipe (1) cannot be eliminated by only one pipe expanding step, the resin pipe after the pipe expansion ( A tensile load may be applied to 1), or the pig (60) may be inserted twice or more.

In the expanded resin pipe (1), the outer peripheral surface of the pipe and the inner surface of the recessed portion (41a) of the pipe axis regulating jig are in contact with each other in the portion where the pipe axis regulating jig (41) is present. To do. Therefore, the lateral displacement of the resin pipe (1) is prevented, the pipe axis is regulated, the pipe diameter is also regulated, and the circularity of at least the lower half of the pipe is secured. At the end portion on the rewinding start end side, as shown in FIG. 5, for positioning and fixing, the upper pipe axis regulating jig (42) is covered with the lower pipe axis regulating jig (41). It is desirable to join the resin pipes (1) by joining the facing surfaces to each other with an adhesive or the like. Also, if necessary, cover the upper pipe axis regulating jig (42) with the lower pipe axis regulating jig (41) also on the portion other than the rewinding start end portion so that the outer peripheral surface of the pipe wall is on the upper side. By making contact with the inner surface of the recess (42a) and joining the upper and lower pipe axis regulating jigs (41) (42) to each other in this state, the tube axis regulation, displacement prevention, and pipe diameter regulation are further strengthened. Is also good. Further, in order to prevent expansion and contraction of the resin pipe after installation, the resin pipe (1) and the pipe axis regulating jig (41) or (42) may be finally joined with an adhesive or the like.

In addition to the jig shown in FIG. 9, the pipe axis restricting jig (40) may have a rectangular parallelepiped shape as a whole by splitting into two pieces as shown in FIG. In FIG. 10, parts having the same names as those in FIG. 9 are given the same reference numerals.

After that, the end of the resin pipe (1) is cut if necessary, and the laying is completed (FIG. 8). In addition, when it is necessary to connect another resin pipe to the laid resin pipe,
It suffices to perform edge processing and connect by a method similar to the conventional method.

FIG. 12 shows a modification of the pig.
In this example, a front projecting neck portion (60b) having a small diameter is provided at the center of the front surface of a pig body (60a) having a heating medium ejection port (62) that opens obliquely outward on the front surface, and the neck portion (60b) is provided. An umbrella-shaped head (60c) having a three-month longitudinal cross-section and a circular cross-section is provided at the tip of the head. Then, a connecting portion (61) with the pulling member (50) is provided at the center of the front surface of the head portion (60c). With such a configuration, as shown in FIG. 12B, the pig main body (60
The heating medium ejected from the heating medium ejection port (62) in a) is
Between the pig body (60a) and the head (60c), the neck (6
0b) can be confined to some extent in the space (70) formed around the space (70b), so that the heat of the heating medium is effectively applied to the tube wall of the resin tube (1) located outside the space (70). The pipe wall can be softened efficiently. Note that, in FIG. 12, portions having the same names as those of the pig shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 13 shows another modification of the pig. In this example, a drain discharge groove (80) having a semicircular cross section with a depth of about 5 to 20 mm is provided on the lower surface of the pig (60) over the entire length in the longitudinal direction. The drain discharge groove (80) plays a role of guiding the drain generated from the vapor as the heating medium to the rear of the pig and discharging it.
Since the frictional resistance between the groove and the inner wall of the pipe is reduced, there is also an effect that the traction force at the time of inserting the pig can be reduced. In the process of expanding and deforming the resin pipe, the pig (6) should be placed so that the drain discharge groove (80) always faces downward.
It is assumed that 0) moves in the resin pipe (1). The configuration of the other pigs is the same as that shown in FIG. 6, and thus the same components are designated by the same reference numerals and detailed description thereof is omitted.

The pigs shown in FIGS. 6, 12, and 13 are all pulled by the pulling member (50).
The pig (60) may be provided with a self-propelled mechanism such as a motor or a self-propelled mechanism by injecting a cooling medium so that the pig (60) can be inserted through the resin pipe while self-propelling. Also in this case, it is preferable to provide the heating medium ejection port on the front surface of the pig and the cooling medium ejection port on the rear surface of the pig. In the case of the self-propelled type, since it is not necessary to insert the pulling member (50) into the resin pipe (1), the resin pipe (1) is rewound from the drum (7) and at the same time the pig (60) is wound. The rewinding step and the tube expanding and deforming step can be performed at the same time by advancing into the tube from the returning side tube opening.

In the above embodiment, the heating medium jetting port (62) is provided for the pig (60) to jet the heating medium. However, instead of jetting the heating medium, electric heating by a heater or the like is performed. A device may be provided in the pig (60) and the resin pipe (1) may be heated and softened by the heating device. Further, the pipe expanding operation by the pig (60) does not necessarily have to be accompanied by heating and softening of the resin pipe, and when the traction force and self-propelling force of the pig (60) are large or the deformation resistance of the resin pipe (1) is large. When it is small, the tube may be expanded and deformed without being softened by heating. Although the pig (60) has a circular cross section, it may have an oval or elliptical cross section together with the pipe axis regulating jig.

[0039]

[Function] Resin pipe (1) after the cross-sectional shape of the pig (60) is deformed
Since the pig (60) having a predetermined cross-sectional shape is inserted into the inside of the resin pipe (1) from one end of the resin pipe (1) to expand and deform the resin pipe (1) into the corresponding cross-sectional shape of the pig, The risk of applying excessive internal pressure, such as when bulging and deforming due to pressure, is eliminated, preferential deformation of the upper portion of the resin pipe and the thin-walled portion that is inevitably produced during manufacturing is prevented, and uneven thickness is also prevented. Moreover, since the resin pipe (1) receives the same internal pressure by the pig (60) regardless of the position in the longitudinal direction,
Even with the construction of long pipes, a uniform cross-section deformation can be obtained in the length direction.

[0040]

Example: 260 mm outer diameter made of hard vinyl chloride resin
A long tubular body having a circular cross section with a diameter of φ, a thickness of 8.0 mm, and a length of 50 m is heated and softened, and is wound around a drum (7) while being deformed into a flat cross section as shown in FIG. 2 (c). I took it.
The width W of the flat resin pipe (1) is 420 mm, the height L2 of the end portion is 55 mm, and the height L3 of the middle portion in the width direction is 35 mm.
Met. Further, when wound on a drum, a plug body (9) with a hose (8) was tightly fitted into the opening of the tip of the resin tube as shown in FIG. 1 (b).

Next, a sealing plug (10) as shown in FIG. 4 is attached to the pipe opening on the rewinding start end side of the resin pipe (1), and then 0.6 kg / g is fed through the hose (8). The resin pipe (1) was laid on the laying surface (30) while introducing steam having a pressure of cm ² for about 10 minutes to soften and unwind the resin pipe (1) and at the same time bulge and deform the resin pipe (1). It is to be noted that a pipe axis regulating jig (41) having a lower shape shown in FIG. 9 is previously embedded in the laying surface (30) in an embedded state, and the rewound resin tube (1) is provided with the tube axis regulating jig. It was laid so as to pass through the recessed portion (41a) of the jig (41), but the unwound resin pipe (1) still had some curl. Therefore, the pumping of the steam was stopped, and the resin pipe was pulled in the lengthwise direction to correct the bend and the twist.

Next, the sealing plugs at both ends were removed, and one end of the resin pipe (1) was connected and fixed to a fixed object such as a manhole. Then, after inserting the piano wire from the pipe mouth, a wire as a pulling member was attached to the piano wire and the piano wire was pulled back to insert the wire into the resin pipe.
Then, after connecting the wire to the connecting portion (61) of the pig (60) having a circular cross section shown in FIG. 6, the pig (60) is inserted into the resin pipe (1) from one end, and the other end side The pig (60) was moved in the length direction of the resin pipe (1) by pulling with a winch. The heating medium and cooling medium supply hoses (66, 67) are connected to the rear surface of the pig in advance, and steam as the heating medium is discharged from the jet port (62) on the front surface of the pig and the jet port (63) on the rear surface. The pig (60) was pulled and moved while ejecting air as a cooling medium from each. The vapor pressure supplied to the pig (60) was 1.2 kg / cm ² , the air pressure was 1.0 kg / cm ² , and the pulling speed of the pig by the winch was 1.0 m / min.

By the movement of the pig (60), the softened resin pipe wall in front of the pig is forcibly expanded and deformed, and the expanded and deformed resin pipe wall is ejected from the rear surface of the pig as the pig moves forward. After that, it was cooled and shaped immediately by the air.

Thus, the pig (60) was inserted over the entire length of the resin pipe (1) to continuously expand the resin pipe, and then the laying work was completed. When the shape of the laid resin pipe (1) was visually observed, it was found that the whole had a substantially circular shape. Further, when examined in more detail, as shown in FIG. 8, the outer diameter of the resin pipe at a position P1 2 m from the rewinding start end side was 267.2 mmφ, and the outer diameter at a position P2 5 m was 267.4 mmφ. , 2 from the other end
The outer diameter at the position P3 of m was restored to 267.5 mmφ. Further, when the resin pipe was cut at the position P2 and the uneven thickness state was examined, almost no uneven thickness was observed.

[0045]

According to the present invention, depending on the above, the resin pipe having a flat cross section is heated and softened, is unwound from the drum and is arranged along the laying surface, or after being arranged,
A pig having a predetermined cross-sectional shape is inserted into the inside of the resin pipe from one end thereof, and the resin pipe is bulged and deformed into a cross-sectional shape corresponding to the pig. Therefore, it suffices if the cross-sectional shape of the pig is made to correspond to the inner diameter of the resin pipe after deformation, so it is possible to eliminate the risk of excessive internal pressure such as when bulging and deforming due to vapor pressure, It is possible to avoid a situation in which the thin-walled portion inevitably occurring is preferentially deformed, and thus uneven thickness can be prevented. Moreover, since the resin pipe receives the same internal pressure by the pig irrespective of the position in the length direction, even when the long pipe is constructed, it is possible to obtain a uniform deformation in the cross section in the length direction.

Moreover, unlike the case where the pipe is deformed under pressure by vapor pressure feeding, it is not necessary to simultaneously cool the entire pipe after the deformation, and it is possible to prevent the pipe from being deformed due to the variation in the contraction rate during cooling.

As described above, according to the present invention, since it is possible to lay a resin pipe having a uniform cross-section without uneven thickness, it is possible to reduce the flow resistance of the fluid in the pipe and also to have excellent durability. sell.

Furthermore, only by changing the sectional shape of the pig,
Since the resin pipe can be easily set to have a circular cross section, an oval shape, an elliptical cross section, or any other desired shape, the flexibility in selecting the cross sectional shape of the laying pipe can be increased.

Of course, since the resin pipe wound on the drum is placed on the laying surface while being heated and softened, not only linear laying but also bending laying is easy, and therefore the flexibility in selecting the pipe line is significantly increased. It goes without saying that you can do it.

According to the pipe forming method of the second aspect, the pig moves in the resin pipe while supplying the heating medium to the front in the traveling direction and the cooling medium to the rear in the traveling direction. Therefore, the heating medium can soften the tube wall in the forward direction of the moving direction, thus reducing the deformation resistance and facilitating the tube expanding process by the pig.
The force required to move the pig can be reduced. And,
After expanding the pipe, it can be cooled and shaped immediately by the cooling medium,
It is possible to lay a resin pipe with even more stable deformation.

[Brief description of drawings]

FIG. 1A is an explanatory view showing an example of a method of manufacturing a resin tube having a flat cross section, FIG. 1B is a perspective view before attaching a plug with a hose to an opening of a winding start end, and FIG. ) Is a longitudinal sectional view of the drum.

FIG. 2A is a sectional view showing a preferable example of a flattened resin pipe, and FIG. 2B is a sectional view showing another preferable example.

FIG. 3 is a cross-sectional view of another flattened resin pipe.

FIG. 4 is a cross-sectional view of an essential part in a state where a sealing plug is attached to one end of a resin pipe.

FIG. 5 is a schematic explanatory view showing a state where the resin pipe is being unwound and placed on the laying surface.

6A is a longitudinal sectional view of a pig, and FIG. 6B is a perspective view of the same.

FIG. 7 is a cross-sectional view showing a state in which a resin pipe expanding process is performed using the pig of FIG.

FIG. 8 is a schematic explanatory view showing a laid state of a resin pipe.

9A is an overall perspective view in which upper and lower tube axis regulating jigs are combined, and FIG. 9B is a lower tube axis regulating jig shown in FIG.
It is sectional drawing cut | disconnected by the IX-IX line.

FIG. 10 is an overall perspective view of another tube axis regulating jig.

FIG. 11A is a cross-sectional view showing a state where the pipe axis regulating jig is arranged on a uniform laying surface, and FIG. 11B is a cross section showing a state where the pipe axis regulating jig is arranged on a laying surface having irregularities. It is a figure.

FIG. 12A is a vertical cross-sectional view showing a modified example of a pig,
(B) is sectional drawing of the state which is performing the pipe expansion process using the pig of (a).

13A is a vertical sectional view showing still another modified example of the pig, and FIG. 13B is a sectional view taken along line XIII-XIII of FIG. 13A.

[Explanation of symbols]

 1 ... Resin tube 1a ... Internal hollow part 7 ... Drum 30 ... Laying surface 60 ... Pig

Claims (2)

[Claims] A thermoplastic hard or semi-rigid synthetic resin tube (1) having a flat cross section wound around a drum (7) is unwound from the drum (7) while being heated and softened, and the laying surface (30 ) Along with the step of arranging it on the laying surface (30) or after arranging it,
A synthetic resin laying, characterized in that a step of inserting a pig having a predetermined cross-sectional shape into the inside of the resin pipe (1) from the one end and expanding and deforming the resin pipe (1) into a corresponding cross-sectional shape of the pig. A method for forming a pipe duct. 2. The synthetic resin laying pipe according to claim 1, wherein the pig moves in the resin pipe while supplying a heating medium to the front in the traveling direction and a cooling medium to the rear in the traveling direction. Pipe forming method.