WO2000060273A1

WO2000060273A1 - Structure and removal method for line pipe lining

Info

Publication number: WO2000060273A1
Application number: PCT/JP2000/001946
Authority: WO
Inventors: Norio Takei
Original assignee: Wamonde Co., Ltd.
Priority date: 1999-03-30
Filing date: 2000-03-29
Publication date: 2000-10-12
Also published as: JP2000283383A

Abstract

A line pipe lining structure, wherein the wall thickness of a lining tube (1) disposed along the inner peripheral surface of a pipe is increased, around the periphery of the tube, according to the amount of wear of that tube caused by a fluid to be transported, whereby the service life of the line pipe can be extended permanently and thus the cost of the lining tube can be reduced to increase a profitability.

Description

Specification

TECHNICAL FIELD The present invention relates to a lining structure of a line pipe and a method of removing a lining.

The present invention relates to a line pipe lining structure suitable for being applied to a pipe line for transporting an abrasive fluid containing earth and sand, coal and ore particles, and a method of removing the lining when replacing a worn lining or the like. It is about. Background art

For example, in hydroelectric power generation, the inventor's earlier proposed technology prevents the accumulation of sediment, organic matter, etc. in the reservoir by sucking and sending the sediment, organic matter, etc., which flowed down into the reservoir, together with the water using a water pipe. (Japanese Patent Laid-Open No. 3-14)

However, rocks with a diameter of about 30 O mm move in the conduit at a speed of about 1 Om / sec, and the amount of wear at the bottom of the conduit is lower than that at the top. It will be 5 times higher than that. Therefore, if a conventional pipe with anticorrosion coating on the inner surface of a steel pipe with tar epoxy resin is used as a water pipe, the bottom will be worn out after about six months of use.

This is because the abrasion of the water pipe generally increases in proportion to the square of the flow velocity, and the larger the particle size, the greater the difference in the amount of wear at the top and bottom.

When a coal slurry containing coal powder with a particle size of about 0.2 to 0.5 mm is transported at a flow rate of 3 to 4 m @ sec, the amount of wear at the bottom is about four times that at the top, and Has a useful life of about 20 years. For irrigation applications with a low sediment contamination ratio, the abrasion of the bottom of the water pipe is about twice that of the top, and its service life is about 40 years.

As described above, the difference in the amount of wear of the water pipe, and hence the service life and the amount of wear at the top and bottom, is greatly affected not only by the flow velocity and the particle size, but also by the specific gravity of the powder fluid, the mixing ratio, and the like. However, in addition to the recent demand for resource and energy savings, business revenues from hydropower, coal slurry transportation, desert greening, etc. In order to improve profitability, extending the service life of the headrace is an extremely important issue.

Then, the inventor proposed the invention according to Japanese Patent Application Laid-Open No. 1-307597 for the purpose of perpetuating the useful life of the line pipe and, consequently, the pipeline. This is because the pipe is lined with a lining tube, and in order to increase the exchangeability when the lining tube is worn, the adhesion between the inner surface of the pipe and the lining tube is reduced without using an adhesive that dries and solidifies. At both ends, adhesive is applied, and in the other parts, the air between the lining tube and the pipe is removed, and the lining tube is pressed against the pipe peripheral surface under the action of atmospheric pressure. On the other hand, removal of the lining tube is based on peeling of the lining tube from the pipe by pressurizing air between the pipe and the lining tube, and then pulling out the old lining tube from the pipe And pulling in the new lining tube.

The present invention is a further improvement of the above-mentioned proposed technology of the inventor from the following viewpoints.Especially, the cost of the lining tube is advantageously reduced, the economic efficiency is improved, and the work of removing the lining tube is performed. It is intended to increase the efficiency of the lining and, preferably, to predict the wear life of the lining tube, thereby facilitating the preparation in advance.

(1) The amount of wear in the circumferential direction varies greatly depending on the specific gravity of the granules, the particle size, the mixing ratio of the granules, and so on. Changing the circumferential thickness of the lining tube in accordance with the amount of wear reduces the tube cost. It can be reduced and more economical.

(2) The length of the pipeline for desert greening and coal slurry transport can be hundreds of kilometers to over 1,000 kilometers, and the worn lining tube must be peeled off in a short period of time over such a long distance. . Similarly, the length of a water-powered water transmission pipe is several tens of kilometers, and a shorter time of stripping is required to shorten the power generation stoppage time. It takes too long.

③ Before the lining is worn out and it is time to replace it, — If it is easy to see that a replacement is needed after a year, the user can easily prepare for the replacement by requesting a new lining tube from the manufacturer in the meantime. Disclosure of the invention

The line pipe lining structure according to the present invention is a line pipe having a lining tube arranged along the inner peripheral surface of the pipe, wherein the thickness of the lining tube is reduced in the circumferential direction by the amount of wear caused by the transport fluid. According to this, the part with a large amount of wear is made thicker and the part with a small amount of wear is made thinner. According to this, after the line pipe has been used for a certain period, the lining tube has reached the end of wear. The remaining wall thickness in the circumferential direction can be made substantially uniform over the entire circumferential direction, so that no excess wall thickness remains in a specific portion of the lining tube. Economic efficiency can be advantageously improved while reducing tube costs and improving raw material yields.

This means that the wall thickness in the circumferential direction of the lining tube was changed in proportion to the wear rate of each part in the circumferential direction of the pipe without the lining tube, and the remaining wall thickness in the circumferential direction of the lining tube was made more uniform. This is especially the case.

Here, preferably, a polyurethane rubber layer having a color different from that of the lining tube is provided on the outer peripheral surface of the lining tube made of soft rubber, and more preferably, the thickness of the urethane rubber layer is set to about one. According to this, complete wear of the lining tube can be confirmed by exposure of the urethane rubber layer, and by predicting the wear of the urethane rubber layer having a specific thickness, the replacement time of the lining can be easily and easily determined. Can be accurately predicted. Since the amount of wear of the urethane rubber differs in the circumferential direction, it is preferable to change the thickness of the urethane rubber layer in proportion to the amount of wear in the circumferential direction.

Further, the method for removing the lining of the line pipe according to the present invention is described as follows. When removing the lining tube from the pipe, remove the lining tube from the pipe by disposing the lining tube along the inner peripheral surface of the

The end portions of the lining tube are peeled off from the pipes, and the end portions are tightened to the respective negative pressure suction tubes inserted into the end portions thereof, and then the air in the lining tube is passed through the negative pressure suction tube. Suctioning and introducing atmospheric pressure between the lining tube and the pipe to separate the lining tube from the pipe over its entire length.

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With this method, peeling off both ends of the lining tube from the pipe is relatively easy because it only needs to be performed against the adhesive, and the air in the lining tube can be removed by removing the air from the lining tube. Since it can be performed more easily and in a shorter time than the press-fitting of air into the pipe, the lining can be removed efficiently. Also, in the method of applying a colored urethane rubber having a predetermined thickness to the outer peripheral surface of the lining tube, it is preferable to vertically move the lining tube up and down, apply a predetermined thickness of urethane rubber to the outer periphery, and heat and vulcanize. . BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing an embodiment of the present invention without a pipe.

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FIG. 2 is an axial partial cross-sectional view showing a separation process of the lining from the pipe. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment in which a lining structure according to the present invention is shown in a cross section except for an outermost line pipe. In the drawing, reference numeral 1 denotes a lining tube. This lining tube 1 made of soft rubber moves from top to bottom It has a circular tube shape whose wall thickness gradually increases. The manufacture of such a lining tube 1 is performed, for example, by measuring the wall thickness of each part in the circumferential direction within the cross section of the worn conventional steel pipe, and measuring the wall thickness of the lining tube 1 so as to be proportional to the wear ratio in the circumferential direction. This is performed by specifying the thickness in the circumferential direction, extruding soft rubber to a length of usually 2 km using an extrusion die manufactured based on this, and continuously vulcanizing and curing it. Can be.

Preferably, a urethane rubber layer 2 having a uniform thickness, for example, a thickness of 1 mra and having a different color from that of the lining tube 1 is adhered to the outer periphery of the lining tube 1, preferably to the outer peripheral surface of the tube. To be provided. The urethane rubber layer 2 can of course be formed by co-extrusion with the lining tube 1, but can also be added after the lining tube 1 has been vulcanized and cured.

In this case, the center axis of the lining tube 1 subjected to the primer treatment is oriented vertically, and the urethane rubber is applied to the outer peripheral surface of the lining tube 1 while maintaining the thickness of the lining tube 1. It is preferable to prevent unevenness in film thickness on the upper, lower, and side surfaces. The excess dripping of the urethane rubber is wiped off, and then the urethane rubber is vulcanized and cured to form an outer periphery of the lining tube 1 as shown in FIG. The urethane rubber layer 2 can be joined to the surface with a substantially uniform thickness over the entire circumference.

More preferably, as shown by phantom lines in FIG. 1, the outer peripheral surface of the urethane rubber layer 2 is further reinforced with a reinforcing sheet 3 so that the action of external force from the inner peripheral side and the outer peripheral side of the lining tube 1 is achieved. On the other hand, deformation of the lining tube 1 in the circumferential and axial directions is sufficiently restrained, and at the same time, the lining tube 1 is effectively prevented from rubbing against the inner circumferential surface of the pipe.

When a specific abrasive fluid of interest is transported in a line pipe having a lining having such a configuration, the lining tube 1 is provided with an amount corresponding to its circumferential thickness during a certain period of use. Wear will be experienced. In this case, if the lining tube 1 is worn substantially evenly over its entire circumference, the lining tube 1 which is normally black Instead, for example, the urethane rubber layer 2, which has become light red, will be exposed on the inner peripheral surface, and this fact can be confirmed by regular endoscopy and the like from a monitoring branch pipe. However, it is possible to clearly recognize that the line pipe liner replacement time is approaching.

By the way, urethane rubber has excellent abrasion resistance, and if the thickness of the urethane rubber layer 2 is 1 mm, it can be used for one to two years after it is exposed. By manufacturing a new lining tube 1 during the grace period, the lining tube 1 can be easily and reliably prepared for replacement.

When the preparation of the new lining tube 1 has been completed in this way and the worn lining tube 1 has been removed from the line pipe, the adhesive is first applied to the inner peripheral surface of the line pipe 4 with both ends. A lining tube 1 having a portion adhered, more precisely, a lining 4 composed of a urethane rubber layer 2 and a reinforcing sheet 3 as shown in FIG. From the flange positions at both ends of 5, peel off the peripheral surface of the pipe against the adhesive force of the adhesive, and then seal each end to the negative pressure suction pipe 6 inserted there, for example, with a string 7. The vacuum inside the lining 4 is removed by suction, for example, with a vacuum pump 8 connected to the respective negative pressure suction pipes 6, and the air is drawn between the pipe 5 and the lining 4. By introducing the pressure, the lining 4 by collapsing the entire length of it, is separated from the Paibu peripheral surface.

According to this, by ensuring the sufficient capacity of the vacuum pump 8, the lining can be performed much easier and in a shorter time than when air is injected between the lining 4 and the pipe 5. 4 can be completely separated from pipe 5

After that, the used lining 4 is pulled out to one side of the pipe 5, and on the other hand, a new lining tube 1 is drawn into the pipe. It can be used repeatedly without substantial damage. Industrial applicability

Thus, according to the present invention, the following remarkable effects can be obtained.

(1) By changing the thickness of the lining tube in the circumferential direction, the cost of the lining tube itself can be reduced and the economy can be improved.

(2) It is easy to find the time to replace the lining tube. In other words, the thickness of the lining tube in the circumferential direction is adjusted to the rate of wear in the circumferential direction due to the abrasive fluid, so that the lining tube made of soft rubber is not worn away and the urethane rubber layer is exposed. This is almost the same period, with no difference in the circumferential direction. Therefore, when the urethane rubber layer is exposed, a wide area in the circumferential direction is exposed, making it easy to find. If the inside of the pipe is regularly checked with an endoscope from the monitoring branch pipe installed at an appropriate position in the pipeline, the exposure of the urethane rubber layer of a different color to the black lining tube can be easily found. So don't overlook.

(3) Since the replacement time of the lining tube is notified in advance, sufficient preparation such as the production of a new lining tube is easy.

(4) At the time of replacement, the lining tube is worn out, and preferably, only the urethane rubber layer and the reinforcing sheet remain. However, the reinforcing sheet is hardly worn and so can be reused.

(5) If the lining tube is replaced according to this method, the inner surface of the pipe will not be worn at all, and the service life of the pipe will be permanent.

(6) Regarding the method of peeling the worn lining, the method of blowing compressed air from the end of the pipe between the pipe and the lining tube by a conventional method and crushing the tube is stagnant in the lining tube It took time to crush the air while expelling it, but in the present invention, if the inside of the lining tube was evacuated with a powerful vacuum pump, the entire length of the lining tube was simultaneously and quickly reduced to a vacuum, and the entire outer circumference became large. It is quickly crushed by the action of air pressure, allowing for quick replacement.

Claims

The scope of the claims

1. In a line pipe in which a lining tube is arranged along the inner peripheral surface of a pipe, the thickness of the lining tube is increased in the circumferential direction according to the amount of wear caused by the transport fluid. Line pipe lining structure

2. The lining structure of a line pipe according to claim 1, wherein the wall thickness of the lining tube in the circumferential direction is changed in proportion to the wear rate in the circumferential direction of the pipe without the lining tube.

3. The line pipe lining structure according to claim 1, wherein a urethane rubber layer having a different color from the lining tube is provided on an outer peripheral surface of the lining tube made of soft rubber.

4. The line pipe lining structure according to claim 3, wherein the urethane rubber layer has a thickness of about 1 mra.

5. The line pipe lining structure according to claim 1, wherein the thickness of the urethane rubber layer is changed in proportion to the amount of wear in the circumferential direction.

6. When removing the lining tube of a line pipe having a lining tube that is arranged along the inner circumferential surface of the pipe and that has both ends adhered to the inner circumferential surface of the pipe,

The ends of the lining tube are peeled off from the pipe, and the ends are fastened to the respective suction tubes inserted into the ends, and then the air in the lining tube is passed through the suction tube. A method of removing a lining of a line pipe, comprising the step of: aspirating and introducing atmospheric pressure between the lining tube and the pipe to separate the lining tube from the pipe over its entire length.

7. In the method of applying colored urethane rubber of a predetermined thickness to the outer peripheral surface of the lining tube,

A method in which the lining tube is moved up and down in the vertical direction, and urethane rubber having a predetermined thickness is applied to the outer periphery thereof, followed by heating and vulcanization.