JP2002369325A - Pressure feed head for laying pipe and laying method using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel pressure feed head for laying pipes and a laying method using it in which air leak from a deformed part of a PE pipe for preventing freeze trouble can be prevented surely. SOLUTION: In the body 11 of a pressure feed head for feeding a hollow pipe P pneumatically into a sheath pipe 1, two or more annular seal members 6a and 6b are provided in the longitudinal direction of the hollow pipe P wherein the interval of the seal members 6a and 6b is set longer than the length at the deformed part S of the hollow pipe P. Even if the deformed part S of the hollow pipe P reaches the position of either seal member 6a or 6b, the other seal member 6b or 6a adheres constantly to the pipe part P thus sealing the pipe and preventing air leak from that part surely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe laying pressure feed head used when laying a hollow pipe for laying an optical fiber cable in a sheath tube, and a laying method using the same.

[0002]

2. Description of the Related Art Conventionally, when an optical fiber cable or the like is buried underground, it is generally laid in a protective tube called a sheath tube made of a polyethylene tube, a steel tube, or the like. When the water that has entered the sheath tube freezes and expands in volume, the optical fiber cable in the sheath tube is pressed, which may cause problems such as an increase in transmission loss and breakage of the sheath tube.
Such a defect is unlikely because it is unlikely to be below freezing in the soil. Such defects frequently occur because they are directly affected.

[0003] Therefore, conventionally, a flexible hollow pipe such as a polyethylene pipe is laid along with an optical fiber cable or the like inside a sheath pipe at a place where there is a danger of freezing. A technique has been proposed and put to practical use in which such a problem is effectively eliminated by absorbing the volume expansion during freezing by the collapse of the hollow pipe.

[0004] This hollow pipe is generally called a PE pipe for preventing freezing. In order to lay the PE pipe for preventing freezing in a sheath pipe, a pulling method has been conventionally applied. Along with the proposal of a construction method of pneumatically feeding the inside of the sheath tube, there is an increasing need to similarly lay the PE pipe for preventing freezing damage by pneumatically. This is because if the pulling method is adopted as the method of laying PE pipes to prevent freezing damage, and the pneumatic feeding method is used as the method of laying optical fiber cables, it will be necessary to arrange, transport, and install separate laying devices at the same laying site. ,
This is because the laying work efficiency is reduced.

[0005] By the way, as described above, PE
In order to lay the pipe by the pneumatic feeding method, after transporting a drum in which a PE pipe for preventing freezing is multilayered in advance to the site, a PE pipe for preventing freezing drawn out from this drum is provided at the end of the sheath pipe. The compressed air is supplied to the inside of the sheath tube in order by the supplied air pressure head (pressure head). At this time, the PE pipe for freezing prevention has a slight flattening due to the winding habit when wound on the drum. When the high-pressure air acts, the flattening is further promoted, and the high-pressure air for pumping is moved to the freezing prevention PE.
It was found that the pipe could not be smoothly pumped because the pipe leaked in the opposite direction from the periphery of the pipe and the flat portion generated a large resistance when passing through the circular seal at the inlet of the pumping head.

For this reason, the present inventors further provided a straightening roller in the pressure feed head, and fed the pressure pipe while correcting the collapse deformation of the PE pipe for freezing prevention to the original shape of a perfect circular cross section by the straightening roller. By doing so, a new air pressure feeding head that prevents air leakage and enables smooth pressure feeding and an air pressure feeding method using the same have been proposed (Japanese Patent Application No. 11-180535).

[0007] The novel pneumatic pumping head and the pneumatic pumping method using the same, as shown in FIG. 6, include a cylindrical pumping head 2 provided at the end of a sheath tube 1 as shown in FIG. When one or more correction rollers 3 having a structure are provided and the PE roller P for preventing freezing failure drawn out by the propulsion caterpillar 5 from the drum 4 is passed, the correction roller 3 is flattened in cross section. PE pipe P to prevent freezing damage by correcting
And an annular sealing member (O-ring) 6 closely contacting therearound
To prevent air leakage from the gap and reduce the resistance at the time of passage to enable smooth air pressure feeding.

That is, as shown in FIG. 7, the correction roller 3 has a plurality of U-shaped support legs 8 arranged in an annular shape on the inner peripheral side of a ring-shaped support member 7, and each of the support legs 8, 8 rotatably support rollers 9 so that a PE pipe P for preventing freezing obstacles passes through a central portion surrounded by the rollers 9, 9,. .. Uniformly press the PE pipe P for preventing freezing from the periphery thereof so as to correct the original shape of the PE pipe P into a true circular cross-section, while suppressing the increase in the passage resistance by the rotation of the rollers 9. It was done.

Accordingly, as shown in FIG. 6, the P for preventing the freezing failure from being pulled out of the drum 4 by the propulsion track 5 is provided.
The E-pipe P passes through the correction rollers 3 provided in the pressure feed head 2 so that its deformation is corrected, and the E-pipe P comes into close contact with the annular seal member 6 so that air leakage from the periphery thereof is suppressed. As a result, the combined force of the pushing force of the propelling caterpillar 5 and the high-speed air flow of the high-pressure air causes the tube to be smoothly fed into the sheath tube 1 and is laid efficiently.

[0010]

As shown in FIGS. 8 and 9, the PE pipe P for preventing the freezing failure has the following features.
From the viewpoint of not only the cylindrical pipe portion p having a uniform outer diameter but also the airtightness of the hollow portion and providing a restoring force at the time of ice melting, the length is approximately 50 mm at intervals of about 2 m.
The one having the irregularly shaped portion S whose cross section is narrowed down in a cross shape is used.

Therefore, as shown in FIGS. 10 (1) and 10 (2), while the irregularly shaped portion S passes through the sealing member 6 on the inlet side of the pressure feeding head 2, the periphery of the PE pipe P for preventing freezing failure is formed. The temporary adhesion loses, and backflow and noise are generated due to severe air leakage from the irregularly shaped portion S, which hinders smooth installation work.

The present invention has been devised in order to effectively solve such a problem, and an object of the present invention is to surely prevent air leakage from a deformed portion of a PE pipe for preventing freezing failure. To provide a new pipe laying pressure feed head and a laying method using the same.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention pneumatically feeds a hollow pipe having a deformed portion having a fixed length at predetermined intervals along a length direction into a sheath tube. A straightening roller that passes through the head body for straightening the shape of the hollow pipe into a true circular cross section,
In a pipe laying pumping head having an annular seal member for sealing around the hollow pipe, two or more annular seal members are provided in the longitudinal direction of the hollow pipe, and the installation interval of the seal members is set to It is longer than the length of the irregular shaped part of the hollow pipe.

Thus, even if the irregularly shaped portion of the hollow pipe reaches the position of one of the sealing members, the other sealing member always comes into close contact with and seals the pipe portion. Can be reliably prevented, and backflow and noise due to severe air leaks can be avoided, and smooth laying work can be performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a pressure feed head 10 for laying pipes according to the present invention.

As shown in the figure, the pumping head 10 for laying a pipe has a longer overall length than that of the conventional one, and is provided at the inlet side of a cylindrical pumping head body 11 which is detachably attached to the end of the sheath tube 1. A pair of correction rollers 3a, 3b
And a pair of seal members 6a and 6b are provided so as to form a pair in the longitudinal direction of the PE pipe P for preventing freezing failure.

The straightening rollers 3a and 3b straighten the flat shape and the like due to the curl remaining in the PE pipe P for preventing freezing failure, which is a hollow pipe passing through the inside thereof, to the original perfect cross-sectional shape. The structure is the same as that of the related art (FIG. 7).

On the other hand, the sealing members 6a and 6b are provided in the vicinity of the correction rollers 3a and 3b, respectively, for tightly contacting the surface of the PE pipe P for preventing freezing and preventing air leakage from the periphery thereof. As in the conventional case, the structure is such that only a very small deformation is allowed in order to withstand the high pressure in the pumping head main body 11.

In this embodiment, the interval between the seal members 6a and 6b is longer than the length (about 50 mm) of the irregularly shaped portion S of the PE pipe P for preventing freezing failure. As shown in the drawing, the interval is such that when the irregularly shaped portion S passes over it. still,
An annular seal (O-ring) 12 having a large diameter is also provided on the outlet side of the pumping head main body 11 so as to seal a gap with the sheath tube 1 when attached to the sheath tube 1. Further, an air inlet 13 is provided in the pressure-feeding head body 11 as in the prior art, so that high-pressure air from a compressor or the like (not shown) is supplied into the pressure-feeding head body 11.

The operation of the pipe laying pressure feed head 10 of the present invention and an example of a laying method using the same will be described above.

First, similarly to the conventional example shown in FIG. 6, a drum 4 around which a PE pipe P for preventing freezing is wound and a propulsion caterpillar 5 are installed on an extension of the end of the sheath tube 1 and the sheath tube is provided. After the pipe laying pumping head 10 of the present invention is attached to one end of the PE pipe P for freezing prevention from the drum 4, the propelling caterpillar 5
Through the pumping head main body 11 and pushed into the sheath tube 1 and inserted as it is over as long as possible.

Next, when such a state is reached, a compressor (not shown) is driven to drive the
At the same time as supplying high-pressure air to the inside, the propelling caterpillar 5 is driven to draw out the PE pipe P for preventing freezing from the drum 4 at a constant speed.
Feed continuously into 1.

Then, as shown by a broken line arrow in FIG. 1, the high-pressure air supplied into the pressure-feeding head main body 11 vigorously flows so as to escape into the sheath tube 1 to form a high-speed air flow. The PE pipe P for preventing freezing failure inserted into the pipe 1 rises to reduce the frictional resistance with the sheath tube 1 and, at the same time, the sheath is smoothly sheathed by the combined force of the high-speed air flow and the propulsive force of the aforementioned propelling caterpillar 5. It is sent into the pipe 1 and laid.

Here, in the pumping head 10 for laying pipes according to the present invention, the sealing member 6 for sealing the periphery of the PE pipe P for preventing freezing in the pumping head body 11 is provided.
Since a and 6b are provided doubly along the longitudinal direction at intervals longer than the length of the irregularly shaped portion S, backflow due to severe air leakage generated from the irregularly shaped portion S as in the prior art And noise can be effectively suppressed to achieve smoother installation.

In other words, as shown in FIG. 2A, at the time of starting the installation of the PE pipe P for preventing freezing failure, the irregularly shaped portion S has not yet reached the inside of the pipe installation pressure feeding head body 10. The periphery of the PE pipe P for preventing the freezing failure is securely sealed by the two sealing members 6a and 6b, and there is no inconvenience that the high-pressure air in the pumping head body 11 leaks out from the periphery. . Further, as described above, the pressure-feeding head body 1
Even if the flattening habit occurs in the PE pipe P for preventing the freezing failure sent into the inside of the pipe 1, the sealing member 6 thereof
correction rollers 3 provided in the vicinity of a and 6b
a, 3b to correct the original cross section to a perfect circle,
Air leakage from the gap due to the curl does not occur.

Next, in this state, the PE pipe P for preventing freezing failure is further fed into the pipe laying pumping head 10, and as shown in FIG. When reaching the sealing member 6a on the inlet side of 10, the adhesiveness with the sealing member 6a is lost, and the sealing function at that portion is lost.
Since one of the sealing members 6b located on the downstream side is securely in close contact with the pipe portion p of the PE pipe P for preventing freezing failure, even if the sealing function of the upstream sealing member 6a is lost. The high-pressure air in the pumping head main body 11 does not leak.

Thereafter, the PE pipe P for preventing freezing failure is further fed into the pipe laying pressure feed head 10 from such a state, and as shown in FIG. 6b, the upstream sealing member 6a again comes into contact with the pipe portion p on the upstream side to restore its sealing function. ), The irregularly shaped portion S reaches the downstream-side seal member 6b,
Although the sealing function is lost, since the sealing function of the sealing member 6a on the upstream side has already been recovered at this point, the high-pressure air in the pressure-feeding head main body 11 similarly does not leak out.

When the deformed portion S passes through the downstream sealing member 6b, the pipe portion p comes into close contact with the sealing member 6b as shown in FIG. 2 (5), and the sealing function is restored again. The periphery of the PE pipe P for preventing freezing failure is reliably sealed by the two seal members 6a and 6b.
Thereafter, the operations shown in FIGS. 1 (1) to 1 (5) are repeated for the irregularly shaped portions S which sequentially flow at predetermined intervals, whereby an excellent sealing function is always exerted. Air leakage is reliably prevented, and a smooth laying operation can be achieved.

Next, another embodiment of the present invention will be described with reference to FIGS.

In the above embodiment, the pair of seal members 6a and 6b are provided in a double manner with a predetermined space therebetween, so that air leakage from the irregularly shaped portion S of the PE pipe P for preventing freezing failure can be achieved. In such a configuration, the passage resistance between the PE pipe P for preventing freezing failure and the sealing members 6a and 6b intermittently increases for a very short time, and the sealing is performed. It is conceivable that a new problem arises in that the members 6a, 6b become severely worn and the life of the seal members 6a, 6b may be shortened.

That is, in the state shown in FIG. 2A, the pair of correction rollers 3a and 3b are connected to the freezing prevention P.
Since it effectively acts on the pipe portion of the E pipe P, even if the pipe portion p has a flat curl, it is corrected by the respective correcting rollers 3a and 3b into an original true circular cross section. As a result, the seal members 6a and 6b having the perfect circular passage holes pass smoothly without causing a large passage frictional resistance.

However, from this state, the PE pipe P for preventing freezing further advances, and as shown in FIG. 2 (2), when the irregularly shaped portion S reaches the correction roller 3a on the upstream side, the irregularly shaped portion S Since the correction roller 3a does not effectively act on S, the curl is not corrected. Then, the winding habit due to the springback is returned at that portion, and the pipe portion p in the vicinity thereof passes through the upstream-side seal member 6a in a state of being flatly deformed.
As described above, since the sealing member 6a has a structure in which only a very small deformation is allowed in order to exhibit a high sealing property, a large friction is generated particularly at the flattened long-diameter portion. It is conceivable that the abrasion progresses locally and the sealing property is impaired in a short period of time. Further, when the PE pipe P for preventing freezing trouble further advances and reaches the state shown in FIG. 2 (4) through the state shown in FIG. 2 (3), the correction roller 3b on the downstream side no longer acts. However, the curl in the vicinity is no longer corrected, and the friction with the seal member 6b in the vicinity also increases, and the sealing performance of the seal member 6b is impaired in a short period of time.

This phenomenon occurs because if the distance between the sealing members 6a and 6b, that is, the distance between the correction rollers 3a and 3b is short, the effect of the correction force of one correction roller sufficiently extends to the other correction roller. Although this does not cause a serious problem, the longer the distance between the correction rollers 3a, 3a, the more the influence of the correction force of one correction roller on the other correction roller becomes more difficult.

For this reason, in the present embodiment, as shown in FIG. 3, a correction roller 3c is further newly provided between the seal members 6a and 6b, specifically, at the center thereof. An increase in friction with the seal members 6a and 6b can be effectively suppressed.

That is, by providing a new correction roller 3c between the seal members 6a and 6b, the deformed portion S reaches the upstream correction roller 3a as shown in FIG. At the time of the correction roller 3b on the downstream side
Not only that, since the shape is corrected by the correction roller 3c at the center, as a result, springback due to curl does not occur at that portion, and even if it occurs, the amount is very small. The frictional force with the seal member 6a in the vicinity thereof is also reduced, and the wear of the seal member 6a can be suppressed.

Further, from this state, the PE pipe P for preventing freezing trouble further advances, and even if the irregularly shaped portion S reaches the correction roller 3b on the downstream side and its operation is no longer possible, the center of the correction pipe at the center of the correction roller 3b is not affected. Since the correcting force of the roller 3c reaches the downstream seal member 6b, the frictional force is reduced, and the wear of the seal member 6b can be effectively suppressed, so that the life of the seal members 6a and 6b due to abnormal wear is reduced. It can be reliably prevented.

In this embodiment, the seal members 6a, 6a,
Although an example in which one correction roller 3c is provided between the correction rollers 6b and 6b has been described, two or more correction rollers may be provided, and it goes without saying that a more remarkable effect can be exerted as the number of correction rollers 3c increases.

In each of the above-described embodiments, the PE pipe P for preventing freezing is laid alone in the sheath tube 1 by the pneumatic feeding method in order to easily explain the method for laying the PE pipe P for preventing freezing. As described in the case, in actual construction, the PE pipe P
Needless to say, it is necessary to lay the optical fiber cable in the sheath tube 1 in addition to the above.

As a method of laying the optical fiber cable, the frost prevention PE pipe P is laid before the laying of the frost protection PE pipe P or as described in the above embodiment.
It is also conceivable to re-lay the cable after the cable is laid, but it is desirable to lay the pipe at the same time as the PE pipe P for preventing freezing failure in consideration of the time and labor required for the laying.

Therefore, in the present embodiment, the Y-shaped branch pipe 14 is not used, as shown in FIG.
In addition, the optical fiber cable C is simultaneously fed from one of the branch pipes 14 and air-fed at the same time as the PE pipe P for preventing freezing failure. The optical fiber cable C is wound around a drum 15 like the PE pipe P for preventing freezing failure, and is fed into the sheath tube 1 via the branch tube 14 by the propulsion track 16.

Therefore, according to this embodiment, the PE pipe P for preventing freezing failure is laid in the sheath pipe 1 via the branch pipe 14, and at the same time, the high speed generated from the pipe laying pressure feed head 10 side. The optical fiber cable C can also be laid in the sheath tube 1 by the airflow and the propulsion caterpillar 16, so that not only the PE pipe P for preventing freezing failure but also the optical fiber cable C can be efficiently laid. In addition, according to the present embodiment, when the optical fiber cable C is pneumatically fed, the pipe laying pressure feed head 1 is used.
Since a high-speed air flow generated from zero can be used, there is an advantage that a compressor head and a compressor for pneumatically feeding the optical fiber cable C can be used.

[0043]

In summary, according to the present invention, since the sealing member for sealing the periphery of the hollow pipe is provided in the inside of the pressure feed head, a hollow pipe having a deformed portion at every predetermined length is laid. Even in this case, a smooth laying operation can be achieved without generating backflow or noise due to severe air leakage. Further, since a new correction roller is provided between the seal members, wear of the seal members is suppressed, and the life of the seal members can be extended. Furthermore, by connecting this pressure feed head to the sheath pipe via the branch pipe, and air-feeding the fiber pipe and the optical fiber cable into the sheath pipe and laying the same, the work of laying the hollow pipe and the optical fiber cable can be performed efficiently. Such an excellent effect can be exhibited.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a pipe laying pressure feed head according to the present invention.

FIG. 2 is an explanatory view showing the operation of the pipe laying pressure feed head of the present invention.

FIG. 3 is a sectional view showing another embodiment of the pipe laying pressure feed head according to the present invention.

FIG. 4 is an explanatory view showing the operation of the pipe laying pressure feed head shown in FIG. 3;

FIG. 5 is an explanatory view showing an embodiment of a laying method according to the present invention.

FIG. 6 is an explanatory view showing an example of a conventional pipe laying method.

FIG. 7 is an enlarged sectional view taken along line AA in FIG.

FIG. 8 is a side view showing an example of a PE pipe (hollow pipe) for preventing freezing damage used in the present invention.

FIG. 9A is an enlarged sectional view taken along line AA in FIG.
(B) is an enlarged sectional view taken along line BB in FIG. 8.

FIG. 10 (1) is a side view showing an example of a conventional pipe laying pressure feeding head. (2) is a conceptual diagram showing a state of air leakage from a conventional pipe laying pressure feeding head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheath pipe 2 Pressure feed head 5 Propulsion caterpillar 3,3a, 3b.3c Correction roller 6,6a, 6b Seal member 10 Pipe laying pressure feed head 11 Pressure feed head main body 14 Branch pipe C Optical fiber cable P PE pipe for freezing prevention (Hollow pipe) S Irregular shaped part p Pipe part

Continuation of the front page F term (reference) 2H038 CA69 5G369 AA05 BA04 DC03 DC10 DC14 EA01

Claims (5)

[Claims] 1. A head main body for pneumatically feeding a hollow pipe having a deformed portion having a fixed length at predetermined intervals along a longitudinal direction into a sheath tube, the shape of the hollow pipe being cross-sectionally true. In a pipe laying pumping head comprising: a straightening roller for passing while correcting the shape of a circular pipe; and an annular sealing member for sealing around the hollow pipe, two annular sealing members are provided in the longitudinal direction of the hollow pipe. A pipe-laying pumping head, comprising the above, and wherein the interval between the seal members is longer than the length of the irregularly shaped portion of the hollow pipe. 2. The pressure feed head for pipe laying according to claim 1, wherein said straightening rollers are provided near each of said seal members. 3. The pressure feed head for laying a pipe according to claim 1, further comprising the correction roller between the seal members. 4. The pipe laying method using the pipe laying pumping head according to claim 1, wherein the hollow pipe is provided in the head body after the head body is attached to an end of a sheath tube. Simultaneously feeding compressed air into the head main body and correcting the shape of the hollow pipe fed into the head main body to a perfect circular cross section with the correction roller, and surrounding each of the sealing members. A method for laying using a pipe laying pressure feed head, wherein the pipe is laid in the sheath tube while sealing with one or both of the above. 5. A pipe laying method using the pipe laying pumping head according to claim 1, wherein the pumping head is attached to the sheath pipe via a Y-shaped branch pipe. An optical fiber cable is fed into the sheath pipe from one of the branch pipes, the hollow pipe is laid, and the optical fiber cable is simultaneously laid in the sheath pipe. Laying method.