JPH091378A - Device for cooling inside of plated tube - Google Patents

Abstract

PURPOSE: To provide a cooling device which prevents the formation of acicular projections due to plating inside a tube, generation of smoke or change of air density inside the tube, at the time of performing working that accompanies heating such as welding on the outer circumference of a steel tube plated at least on the inside surface. CONSTITUTION: This device performs partially cooling the inner circumferential surface of a tube which is plated at least on the inner surface and which is heated in a working operation accompanying heating on the outer circumference of the tube. The device is so structured that a space to be cooled inside the tube is sectionally formed into a chamber 22 hermetically sealed with a pair of sealing means 11, 12 arranged in the front and back of the space, and that the chamber 22 is communicated with a pipe 23, 29 for feeding a cooling medium and similarly with a pipe 30 for discharging it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a plated pipe, and more particularly to a device for cooling the inner peripheral surface of a steel pipe which is galvanized at least on the inner side when welding or the like. .

[0002]

2. Description of the Related Art In recent years, undergrounding of electric power or communication cables has been promoted. This type of cable is buried underground by burying a small-diameter pipe and passing the cable through it. Generally, steel pipes or plastic pipes are used, but steel pipes are often used in terms of strength and cost.

In burying underground power or communication cables using steel pipes, a small-diameter propulsion method is often used for burying steel pipes. With this small-caliber propulsion method, an underground part (starting pit) is formed in the ground just enough to accommodate the propulsion unit, and the propulsion unit is installed so that it can slide back and forth.

Then, first, the leading pipe is propelled from the starting shaft into the ground, and then a steel pipe is connected to the rear end of the leading pipe for further propelling. After that, steel pipes are successively added,
As a result, a buried pipe having a predetermined distance is formed.

At that time, when changing the direction of the leading conduit,
A slope plate is provided at the tip of the front conduit, and the earth pressure received by this slope plate is used. Therefore, it is necessary to control the direction of the slope plate at the tip of the leading conduit by rotating the entire propelling pipe from the starting shaft. Therefore, it is necessary that each steel pipe is connected with a predetermined strength.

Therefore, in the prior art, as shown in FIG. 6, about half of the sleeve pipe 2 is fitted to one end 1a of each steel pipe 1, and one end portion 2a of the sleeve pipe 2 is welded to the outer peripheral portion of the steel pipe 1 by fillet welding. A welded portion (denoted by reference numeral 3) and fixed (this is referred to as a laying pipe 4 for convenience) is manufactured in advance in a factory.

At the construction site, the other end 1b of the steel pipe 1 in the newly installed laying pipe 4 is inserted into the sleeve pipe 2 provided at one end 1a of the steel pipe 1 in the laying pipe 4 that is propulsively buried from the starting shaft. The other end portion 2b of the sleeve pipe 2 is inserted and fitted, and the other end portion 2b of the sleeve pipe 2 is fillet-welded to the outer peripheral portion of the other end 1b of the steel pipe 1 which has been rejoined.

[0008]

By the way, this kind of steel pipe is generally galvanized. Therefore, in the conventional small-diameter propulsion method, when the new laying pipe 4 is fixed to the already laid laying pipe 4 by welding or the like as described above and added, as shown in FIG. The zinc plating on the inner peripheral surface is oxidized and melted by the heat applied to the inner peripheral surface, and a large number of needle-like protrusions 5 are formed on the inner peripheral surface like fluff.

The needle-like protrusions 5 caused by such melting of the plating have a problem that the cable covering portion is damaged when the power or communication cable is pulled into the pipe and passed through, and its function is affected. Further, there is also a problem that the generation of needle-shaped protrusions due to the melting of plating causes the generation of rust because the plating is substantially lost at that portion, which shortens the life of the steel pipe.

Further, in recent years, it has been necessary to strengthen the welding strength as the propulsion distance is lengthened, and there is a dilemma with respect to the influence on the plated portion. That is, there is a conflicting relationship that if the welding power is increased, the plating will be damaged, and conversely, if the plating portion is protected, the welding power will be reduced.

However, conventionally, since it is necessary to give priority to strengthening the welding force, the needle-like protrusions of the plating generated on the inner peripheral surface after welding are scraped off and ground, and then that portion is repainted. When the sleeve pipe 2 is fitted to one end of the steel pipe 1 and fillet welding is performed to form the laying pipe 4, this work is performed in advance in the factory as described above, and the welded portion is the end portion of the steel pipe. Since it is near the open portion, the work is relatively easy even if the needle-like protrusions of the plating are scraped off and repainted.

However, when another laying pipe is connected to the laying pipe 4, the work is at the site of the burying work, and the length from the end opening of the single pipe to which the welded portion is added to the welded portion. Since it is almost the entire length of the steel pipe, it is a very difficult work to scrape off, sharpen, or repaint the plating needle-shaped protrusions that have occurred on the inner peripheral surface of the welded part. It took a lot of time and effort.

Further, in the above-mentioned welding when connecting the steel pipes, smoke is generated due to oxidation of the plating and remains in the pipe, and it is necessary to discharge the smoke. Moreover, even during the welding work or the post-welding propulsion work, if you try to confirm the direction of the buried pipe from the starting shaft with a target such as a transit, the welding heat or residual heat after welding There is also a problem that the air density in the tube is changed, and therefore the target collimation is refracted and the correct direction cannot be confirmed.

In particular, the light-emitting diode used as a target often uses a red color which has the highest brightness, and the red color has the highest refractive index, so that the above-mentioned problems cannot be ignored. Was there.

In order to eliminate such inconvenience, in welding under the temperature condition where the plating layer on the inner peripheral surface of the steel pipe is not destroyed or the density of the air in the pipe is not changed, multi-layer welding is performed and the working time is too long. There is a problem that it takes too much.

The object of the present invention is to solve the above-mentioned problems of the prior art. When performing a working operation involving heating such as welding on the outer peripheral portion of a steel pipe having at least its inner surface plated, An object of the present invention is to provide a plating pipe cooling device that prevents formation of needle-like protrusions due to oxidation and melting of plating in the pipe, generation of smoke, and changes in the density of air in the pipe.

[0017]

The present invention is a plating tube cooling device, which is configured as follows in order to solve the above-mentioned technical problems. That is, the present invention is a plating pipe cooling device that partially cools the inner peripheral surface of a pipe portion heated at the time of performing a working operation involving heating at least on the outer periphery of the pipe whose inner surface is plated. A pair of sealing means disposed before and after the portion to be cooled and partitioning and forming a sealed chamber, one end communicating with the sealed chamber through one of the sealing means and the other end installed outside the plating tube A cooling medium supply pipe connected to a cooling medium supply source,
It is characterized in that one end is connected to the sealed chamber through one of the sealing means, and the other end is constituted by a cooling medium discharge pipe opened to the outside of the plating pipe.

<Additional Configuration in the Present Invention> The cooling device for a plating pipe according to the present invention comprises the above-mentioned essential components, but the following configuration is added to the components. . The additional component is that a see-through tube whose both ends are open is installed on the central axis of the plating tube by penetrating the pair of sealing means and the sealed chamber defined by the sealing means.

The cooling device for a plating pipe according to the present invention is realized even when the constituent elements are specifically as follows. The additional components are a support body provided with traveling means such that the pair of sealing means can move in the pipe, and an outer peripheral surface of the support body, which is expandable radially outward. And a flexible tube, and the plating tube cooling device further includes an expansion medium supply device for injecting an expansion medium into the tube.

Further, in the plating pipe cooling device of the present invention,
It is also possible to provide a supply device capable of supplying compressed air from the cooling medium supply pipe so as to discharge the cooling medium from the cooling medium supply pipe, the closed chamber and the cooling medium discharge pipe.

[0021]

According to the cooling device for a plated pipe of the present invention, the end of a new steel pipe is fitted into the sleeve attached to the end of the steel pipe that has already been buried and propelled. After that, the main plating pipe cooling device is inserted from the end opening of the fitted steel pipe, and the inner peripheral part of the fillet welding scheduled part for welding the sleeve pipe and the steel pipe is formed in the closed chamber formed between the pair of sealing means. To be located.

Alternatively, a cooling device for the main plating pipe is placed inside a new laying pipe in advance, and the steel pipe end portion of this laying pipe is fitted into the sleeve pipe located at the end portion of the laying pipe which has been already buried and promoted. You may do it.

Then, each sealing means is operated to partition the inside of the pipe between them into a closed chamber. After that, the above-mentioned welding work is started, and at the same time, the cooling medium is introduced into the closed chamber from the supply pipe and discharged from the discharge pipe. As a result, the inner peripheral portion corresponding to the outer peripheral welded portion of the steel pipe is cooled by the cooling medium, so that the plating layer on the inner surface of the steel pipe is not oxidized and melted by heating, so that the needle-like protrusions are generated by the plated layer. Is prevented.

A flexible member is attached to the outer peripheral surface of a support body having a traveling means capable of moving inside the pipe, and the flexible member is expanded radially outward. In such a case, the closed chamber is formed by introducing gas into the flexible member provided on the outer peripheral portion of each support to expand the flexible member and bring it into close contact with the inner peripheral surface of the steel pipe.

Further, when it is desired to confirm the direction of the buried pipe during the welding operation as described above by using a transit or the like from the starting shaft to confirm the target provided in the leading conduit, a pair of sealing means and partition formation are performed by these means. It collides with the target through a transparent tube which penetrates through the closed chamber and is opened on both sides of the central axis of the steel tube.

Further, when the cooling device in the plating pipe is to be pulled out after the completion of the welding work, an expansion medium such as compressed air is supplied to the cooling medium supply pipe in advance so that the cooling medium does not diffuse into the laying pipe. Almost all cooling medium is discharged from the pipes, closed chamber and cooling medium discharge pipe.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The cooling apparatus for a plating pipe according to the present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 shows a cooling device 10 for a plating pipe according to an embodiment of the present invention. As mentioned above, in the small-diameter propulsion method, the steel pipe (laying pipe) with the sleeve pipe is sequentially connected from the starting shaft to the tip conduit 7 with the direction-correcting blade tip 6 and the target 7 on the central axis being connected in sequence. To be done. Such a construction method itself is the same as the conventional one.

The plating pipe cooling device 10 of this embodiment is
In the case of connecting and fixing a new laying pipe 4 to the laying pipe 4 already propulsion buried, the steel pipe end of the new laying pipe 4 is fitted into the sleeve pipe 2 of the laying pipe 4 already propulsion buried, A device for cooling the inner surface of the steel pipe during meat welding, which is arranged before and after the planned cooling portion in the steel pipe 1,
A pair of sealing means 11 and 12 for partitioning and forming a closed chamber are provided.

Since the respective sealing means 11 and 12 are almost the same, only the structure of one sealing means 11 will be described. As shown in FIG. 2, the sealing means 11 includes a support 15 having two disc-shaped spokes, that is, spoke discs 14a and 14b, which are attached to an axially central portion of a tubular rim 13 with a space therebetween.

As shown in FIG. 3, a rubber annular band 16 is attached to the outer peripheral surface of the rim 13, and both ends of the annular band 16 are fixed to the outer peripheral surface of the rim 13 by retaining rings 17. ing. The space 18 between the two spoke discs 14a and 14b provided at the axial center of the cylindrical rim 13 has a large number of vent holes 19 formed in the rim 13.
And communicates with the outside of the outer surface of the rim 13.

The two sealing means 11 and 12 are shown in FIG.
As shown in, they are arranged side by side and are fixedly connected. As this connecting means, each support 15
A communication pipe 20 for connecting the spoke plates of each support body 15 so as to connect the space 18 between the spoke plates 14a, 14b.
Further, it is a see-through tube 21 having both ends open, which is provided on the central axis line through the respective spoke plates 14a and 14b.

As shown in FIGS. 2 and 4, a ring-shaped pipe 23 is arranged in the space portion 22 connected to each other with a space therebetween in this way. A large number of cooling water ejection holes 24 are formed on the outer peripheral portion of the ring-shaped pipe 23.

Further, on the outer side portions of the pair of sealing means 11 and 12 which are integrally connected, as shown clearly in FIG. It is fixed to the inner surface of the rim 13 by welding or the like. Casters 26 are fixed to the outside of each side of the bracket 25, and the casters 26 contact the inner surface of the steel pipe 1 at three points to movably support the sealing means 11 and 12.

The in-plating pipe cooling device 10 thus constructed is further provided with an air supply pipe 27 for supplying compressed air to the space 18 between the spoke plates 14a and 14b of the one sealing means 12. The air supply pipe 27 has one end connected to the spoke board 14b and the other end fixed to a stay 28 attached to the see-through pipe 21.

Similarly, one end of a cooling water supply pipe 29 is supported by this stay 28, and the other end has one sealing means 1.
2 through the spoke plates 14a, 14b and are fixed to the inner peripheral portion of the ring-shaped pipe 23 described above, and are communicated with each other by communication holes as shown in FIG.

Further, the cooling water discharge pipe 3 is provided in the stay 28.
0 has one end supported and the other end has one sealing means 12
Through the spoke discs 14a and 14b in FIG.

In these three pipes, that is, the air supply pipe 27, the cooling water supply pipe 29 and the cooling water discharge pipe 30, the stay 2 is provided.
Flexible hoses are connected to the respective ends projecting from 8, and are connected to a compressed air supply source, a cooling water supply source, a cooling water pool, etc. installed outside the laying pipe 4.

Next, the operation of the plating pipe cooling device 10 of the above-described embodiment will be described. First, the end of the steel pipe 1 of the new laying pipe 4 is fitted into the sleeve pipe 2 of the laying pipe 4 which has already been pushed and buried. After that, the main plating pipe cooling device 10 is inserted from the end opening of the fitted steel pipe 1, and the caster 2
6, the inner peripheral surface of the fillet welding planned portion for moving the inside of the pipe to weld the sleeve pipe 2 and the steel pipe 1 has a pair of sealing means 11, 1
It is located in the space 22 between the two.

Alternatively, the plating pipe cooling device 10 is placed in a new laying pipe 4 in advance, and then the end of the steel pipe 1 of the laying pipe 4 is located at the end of the laying pipe 4 which has been already buried and propelled. Fit inside. Then, in the plating pipe cooling device 10, the plating pipe cooling device is arranged such that the inner peripheral surface of the fillet welding planned portion for welding the sleeve pipe 2 and the steel pipe 1 is located in the space 22 between the pair of sealing means 11 and 12. Correctly adjust the position of 10.

Then, as shown in FIG. 1, the compressed air supply source 31 installed outside the laying pipe such as the starting shaft is operated, and the compressed air is supplied to one side through the solenoid valve device 32, the hose and the air supply pipe 27. It is introduced into the space 18 between the spokes 14a and 14b of the support 15 which constitutes the sealing means 12. The compressed air is also introduced into the space portion 18 between the spoke plates 14a and 14b of the support 15 which constitutes the other sealing means 11 through the communication pipe 20.

The compressed air introduced into these space portions 18 is blown out from a large number of vent holes 19 formed in each rim 13 to expand the band 16. When the band 16 expands and comes into close contact with the inner wall surface of the steel pipe 1, the gap 22 between the pair of sealing means 11 and 12 cooperates with the steel pipe 1 to form a closed chamber.

Thereafter, the cooling water is supplied from the cooling water pool 34 by the cooling water supply pump 33 to the hose and the cooling water supply pipe 2.
Water is sent to the ring-shaped pipe 23 via 9 and is jetted toward the inner wall of the steel pipe from a large number of cooling water jet holes 24 formed in the outer peripheral portion of the pipe 23. At the same time, fillet welding of the sleeve pipe 2 and the steel pipe 1 is started.

As described above, when the cooling water is jetted into the pipe 23 through the large number of jetting holes 24 in the sealed space portion 22, that is, the sealed chamber, the cooling water is stored in the sealed chamber 22 and its level is cooled. When it reaches the open end of the water discharge pipe 30, it is discharged from the cooling water discharge pipe 30 to the outside of the steel pipe through the hose and returned to the cooling water pool 34. As a result, the inner peripheral portion corresponding to the outer peripheral welded portion of the steel pipe is cooled by the cooling water, so that the plating layer on the inner surface of the steel pipe is not heated and melted, so that the occurrence of needle-like protrusions due to the plating layer is prevented. .

When it is necessary to confirm the propulsion direction of the buried pipe with the main pipe cooling device 10 left inside the laying pipe 4 during the welding work or after the welding work is completed, it is installed in the starting shaft. The transit T penetrates through the pair of sealing means 11 and 12 and the closed chamber 22 defined by these, and is provided in the front conduit 8 through the see-through tube 21 with both ends opened installed on the central axis of the steel tube 1. Target 7
Align the collimation with.

When the fillet welding between the sleeve pipe 2 and the steel pipe 1 is completed and the welded portion is sufficiently cooled, the supply of cooling water is also stopped. However, in the cooling water supply pipe 29, the closed chamber 22
The remaining cooling water that has not been completely drained remains inside and in the cooling water discharge pipe 30. Particularly, when the buried pipe is installed at a downward slope, almost all the cooling remains in the cooling water supply pipe 29, the closed chamber 22, and the cooling water discharge pipe 30. Therefore, compressed air is supplied to the cooling water supply piping system from the compressed air supply source 31 connected to the cooling water supply piping system through the solenoid valve device 35, and the compressed air in the sealed chamber 22 is discharged while increasing the atmospheric pressure.

As a result, the cooling water remaining in the cooling water supply pipe 29, the closed chamber 22 and the cooling water discharge pipe 30 is drained to the outside of the steel pipe through the cooling water discharge pipe 30, and in particular, the drainage path. The cooling water remaining in the corners of the tank is also discharged at the wind speed, and as a result, most of the cooling water is discharged.
Although very little cooling water remains at the end, this amount of water has almost no effect on the work and can be ignored.

Thereafter, the compressed air in the band 16 of each of the sealing means 11 and 12 is exhausted and contracted, and the cooling device 10 is pulled out of the laying pipe. Then, the normal laying pipe propulsion work is continued. Alternatively, it is also possible to perform a normal laying pipe propulsion work while leaving the plating pipe cooling device 10 inside the laying pipe 4, and pull out the plating pipe cooling device 10 left after the completion of the propulsion to the outside of the laying pipe.

In the plating tube cooling device of the above-described embodiment, water is used as the cooling medium, and the tube 17 is used.
Although compressed air was used as the gas for expanding the slag, this is merely an example and any cooling medium and expansion gas may be used.

Further, in the plating pipe cooling device of the present embodiment, it was used to cool the inner peripheral portion when the laying pipes were welded and connected, but the present invention is limited to such use. Not to mention, it is needless to say that it is effective for partially cooling the inner peripheral surface of the pipe portion when performing various processing operations involving heating on the outer peripheral portion of the laid pipe.

[0050]

As described above, according to the plating pipe cooling apparatus of the present invention, when performing various processing operations involving heating on the outer peripheral portion of the plating pipe, the inner peripheral surface can be relatively easily partially removed. Since it can be cooled to a high temperature, it is possible to prevent the generation of needle-like protrusions due to the melting of the plating, and as a result, there is no need to perform the work such as scraping off the needle-like protrusions and repainting, which has been done conventionally. It is possible to prevent damage to the coating portion of the cable such as electric power that is passed through the laying pipe and generation of rust.

Therefore, sufficient welding work strength can be obtained without paying attention to the influence of the welding heat on the plated portion, and during such a working operation or while the plating pipe cooling device is left in the laying pipe. Even in this state, it is possible to perform the target visual confirmation work by transit, which is a great effect.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing the whole of a plating pipe cooling device according to an embodiment of the present invention, which is installed in a laying pipe buried in the ground.

2 is an enlarged cross-sectional view showing a cooling device in a plating tube of the embodiment shown in FIG.

FIG. 3 is a cross-sectional view partially enlarging one sealing means that constitutes the plating pipe cooling device shown in FIG.

FIG. 4 is a vertical cross-sectional view of the cooling device in a plating tube, which is cut along the line 4-4 in FIG.

FIG. 5 is a vertical cross-sectional view of the cooling device in the plating tube, which is cut along the line 5-5 in FIG.

FIG. 6 is a cross-sectional view of a conventional laying pipe that schematically shows a generation state of needle-like protrusions generated by melting of a plating layer on an inner peripheral portion when the outer peripheral portion of the pipe is welded when connecting the laying pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steel pipe 2 Sleeve pipe 3 Fillet welded part 4 Laying pipe 10 Cooling device in plating pipe 11 Sealing means 12 Sealing means 13 Rim 14a Spoke machine 14b Spoke machine 15 Support body 16 Annular band 17 Retaining ring 18 Space part 19 Vent hole 20 Communication pipe Reference numeral 21 Fluoroscopic tube 22 Interval (closed chamber) 23 Pipe 24 Cooling water ejection hole 25 Bracket 26 Caster 27 Air supply pipe 28 Stay 29 Cooling water supply pipe 30 Cooling water discharge pipe

Claims (4)

[Claims] 1. A cooling apparatus for a plating pipe, which partially cools an inner peripheral surface of a pipe portion heated at the time of performing a working operation involving heating on the outer periphery of a pipe having at least an inner surface plated, wherein cooling is performed inside the pipe. A pair of sealing means arranged before and after a predetermined portion and partitioning and forming a hermetic chamber, and one end communicating with the hermetic chamber through one of the sealing means and the other end being installed outside the plating tube A cooling medium supply pipe connected to a medium supply source, and a cooling medium discharge pipe having one end communicating with the sealed chamber through one of the sealing means and the other end opened to the outside of the plating pipe. The cooling device in the plating pipe, which is characterized in that 2. The plating tube cooling device further penetrates the pair of sealing means and the sealed chamber defined by the sealing means, and is provided on the central axis of the plating tube and is open at both ends for perspective. The plating pipe cooling device according to claim 1, further comprising a pipe. 3. A support body, wherein each of the pair of sealing means is provided with a movable means capable of moving inside the pipe, and a flexible body which is attached to an outer peripheral surface of the support body and is expandable radially outward. 3. The cooling device for the inside of the plating tube further comprising an expansion member, and an expansion medium supply device for injecting an expansion medium into the flexible member. Cooling device inside the plating tube. 4. The plating pipe cooling device supplies an expansion medium such as compressed air from the cooling medium supply pipe so that almost all of the cooling medium is discharged from the cooling medium supply pipe, the closed chamber and the cooling medium discharge pipe. The plating tube cooling device according to claim 1, 2 or 3, wherein the cooling device is provided with a device capable of performing the cooling.