JPS58217339A - Lining method of inner surface of pipe - Google Patents

Abstract

PURPOSE:To coat even a long-sized pipe with excellent workability by flattening and fast sticking a rubbery elastic body tube, winding bands on the outer surface of the tube at proper intervals, inserting the tube into the pipe, forwarding air, etc. by pressure, and breaking the bands while compression-bonding the tube with the inner surface of the pipe. CONSTITUTION:The thin circular tube 1 made of a rubbery elastic body is flattened and fast stuck, and bent in a U-shaped and volute section while the outer surface of the tube 1 is coated with a viscous fluidized material such as rust preventive grease. Bands 2 such as a gummed tape are wound at proper intevals in the longitudinal direction, and righting moment to a circular section of the tube 1 is inhibited. A wire 6 is connected at one end of the tube 1 on which the bands are wound, and the tube is pulled into a long-sized steel pipe (such as one of 2km length) 4 by pulling the wire 6 and inserted into the other end. One end of the tube 1 is expanded to a trumpet shape and pushed against the flange 5A surface of the steel pipe 4, air, etc. are forwarded into the tube 1 by pressure to break the bands 2 while the tube 1 is returned to the circular section, and a coating layer for the inner surface of the pipe is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for lining the inner surface of a tube, and particularly to a method for lining the inner surface of a tube suitable for forming an inner surface coating layer of a long pipeline constructed by welding and connecting steel pipes.

Conventionally, when applying anti-corrosion coating or lining to the inner surface of long steel pipes such as pipelines, the coating or lining is usually applied to a single steel pipe (for example, 5 to 6 m long) before connection. The latter steel pipes were connected using methods such as welding, 7-lunge joints, or screw fastening.

With flange joints and screw fastenings, it is difficult to ensure the sealing performance of the connection part, and there are also drawbacks such as the fastening part loosening due to vibration or impact, causing leaks, and the construction cost being enormous. For this reason, welded connections are widely used as pipelines for conveying natural gas, oil, or slurry.

When welding connections using the conventional internal surface model method, the coating film or lining material burns due to welding heat, so do not apply coating or lining to the high temperature range (usually within about 150 m from the welding point). The method employed was to have a worker enter the pipe and paint the area after the welded connection was completed. However, if the inner diameter of the pipe is small (for example, 800 mm or less), people cannot enter the pipe, so the inner surface of the welded part must be left unpainted. Unfortunately, when it is necessary to paint the entire inner surface of a small-diameter pipe, a 7-lunge joint or threaded joint must be used.

As mentioned above, flange joints are significantly more expensive to construct than welded joints, and their airtightness is less reliable, resulting in large maintenance costs. On the other hand, for threaded joints, the inner diameter of the pipe is 15
It is limited to small diameter pipes of 0W or less, and since the thickness of the threaded portion of the pipe is reduced by the depth of the thread root, it is necessary to increase the thickness by that amount in order to ensure strength. Furthermore, there are disadvantages in that the thread surface cannot be sufficiently anti-corrosion treated, stress concentration occurs in the root of the thread when longitudinal tensile force or bending force is applied, making it easy to break, and screws tend to loosen due to vibration or impact. There are many problems such as the following drawbacks.

In order to solve the above-mentioned drawbacks, a method has been proposed in which a pig is passed through the pipe after the pipeline is welded and the inner surface is painted using this pig, but this method also has the following drawbacks: There is.

(1) Pretreatment is required before painting the inside of the pipe.

Namely, foreign matter removal, degreasing, scale removal with hydrochloric acid,
Various processes such as ammonia neutralization, water washing, chemical conversion treatment, and dehydration require considerable cost and equipment, and the construction period is also long.

(1) The thickness of one coat is approximately 0.1 #, and in order to form the required film thickness, it is necessary to insert the pig many times, and it is also necessary to dry and cure each time. In particular, in cases of severe wear such as in slurry piping, a film thickness of 2 cm or more is required, further prolonging the construction period.

It) Compared to when a person enters the pipe and paints directly,
Pretreatment, painting, inspection, repair, pipe temperature control (prevention of condensation)
etc. have low reliability.

6V) In the case of high-pressure gas piping, high-pressure gas permeates through the coating film and enters between the inner surface of the pipe and the coating film, and when the gas pressure decreases, the permeating gas expands, causing the coating film to peel off.

(V) When steel pipes are connected from the outside by uranami welding, uranami (protrusions of weld metal) with a height of 2 to 3 nodes protrude on the inner surface of the pipe, but when painting through pigs, the coating thickness of this uranami portion is The surface becomes thinner than other parts, and the corrosion protection performance decreases significantly.

The purpose of the present invention is to eliminate the drawbacks of the prior art described above,
To provide a method for lining the inner surface of a pipe, which has excellent workability and can form a reliable inner surface coating layer even for a long pipeline.

A feature of the present invention is that after a pipeline is laid by connecting pipes such as steel pipes by welding, a thin-walled tube made of a rubber-like elastic material is inserted into the inner surface of the pipeline, and the outer surface of the tube is brought into close contact with the inner surface of the pipe to form a lining. It is to form.

That is, according to the present invention, a tube made of a rubber-like elastic body having an outer diameter equivalent to the inner diameter of the tube is successively flattened and brought into close contact with one end thereof, and the flat tube is bent into a U-shaped or spiral cross section, and the outer surface of the tube is The step of applying a sticky fluid to the tube and wrapping it with bands at appropriate intervals in the length direction in order to suppress the restoring force to the circular cross section of the tube, and this band wrapping is performed when the tube is connected by welding to a pipeline or the like. The steps of inserting the pipe from one end to the other and wrapping the band are performed by forcing air or a pig into the tube to break the band and sequentially returning the tube to a circular cross section while crimping it onto the inner surface of the pipe. There is provided a method for lining an inner surface of a tube, characterized in that the tube has several stages i, and a tube inner surface coating layer is formed using the tube.

Hereinafter, the present invention will be described in detail with reference to the drawings.

A large number of steel pipes (for example, 5 to 5 m each) such as pipelines (for example, QKm length) are welded together to produce a tube with an outer diameter equivalent to the inner diameter of the installed pipe.

As shown in FIG. 1, this tube 1 is a thin-walled tube with a circular cross section (for example, three fins and an outer diameter of 500 vma), and its material is a rubber-like elastic body such as natural rubber, synthetic rubber, or synthetic resin. Further, the tube 1 is manufactured to a predetermined length by connecting tubes of standard length with adhesive as necessary so that the length thereof is slightly longer than the length of a predetermined pipeline.

The wall thickness of the tube 1 is determined depending on the properties of the fluid passing through the tube, the required service life of the pipeline, etc., and is usually selected to be 2 or more thick.

The tube 1 shown in FIG. 1 is first made into a cross-sectional shape as shown in FIG. 2 by successively flattening it from one end to the other.

Next, this flat tube is bent into a U-shape as shown in FIG. 3 or a spiral cross-section as shown in FIG. Apply. When applying this fluid, if necessary, the sticky fluid is heated to lower its viscosity and improve workability. These processes have just begun.

This is done until the air in the tube is expelled until the other end is reached.

Following the work of bending the tube 1 into the aforementioned U-shaped or spiral cross-section, bands 2 are sequentially wound around the tube at appropriate intervals in the longitudinal direction of the tube, as shown in FIG. This band 2 serves to suppress the restoring force that tends to return the tube 1 to its circular cross-section, and it is sufficient if it has enough strength to withstand the restoring force.

As the band 2, a material that is sufficiently thin compared to the thickness of the tube 1, such as an adhesive tape such as gummed tape, is used. Further, the interval between each band 2 is determined in consideration of the restoring force of the tube 1, and the larger the wall thickness is compared to the diameter of the tube and the larger the restoring force, the more densely the band needs to be wound.

At the stage where the tube 1 is flattened and brought into close contact, the air inside the tube is expelled to the other end. It is preferable to prevent air from entering. Also,
After completion of the flattening work, it is preferable to similarly apply a sealant to the inner surface of the final end side and press-fit it to prevent air from entering. By sealing both ends with sealant in this way,
The restoring force of the tube can be temporarily reduced.

Further, as shown in FIG. 5, each band 2 is preferably provided with notches 3 in the same direction to facilitate the cutting operation described later.

After the tube 1 is wrapped in a band as shown in FIG. 5 in the above steps, it is rolled and transported to a piping construction site such as a pipeline.

On the other hand, during piping work, each individual steel pipe is connected with a welded joint, and as shown in Fig.
Weld 7 flanges 5A and 5B to both ends of piping) 4.

In addition, a wire 6 for drawing the tube 1 is inserted into the pipe line 4.

After the above work is completed, the wire 6 is connected to one end of the tube 1, and the wire 6 is pulled to pull the tube 1 into the pipe line 4. Pull it in until it comes out from the end.In this way, the tube 1 is inserted into the pipe line 4.

Next, band wrapping is performed by opening the crimp-sealed portion of the tube end on the side corresponding to the direction in which the notch 3 of the band 2 of the tube 1 (see FIG. 5) is formed, returning the tube to a circular cross section, and then wrapping the tube. The end is expanded into a trumpet shape and pressed against the surface of the flange 5A of the pipeline, and then tightened by the 7 flange 7A4C to fix in an airtight state. This state is shown in Figure 6.

Next, by pumping compressed air, pressurized water, or VIG into the tube 1 from its open end, each band 2 is broken and the tube 1 is successively returned to its circular cross-section and crimped onto the inner surface of the tube. At this time, the air remaining in the cavity 8 between the tube 1 and the inner surface of the pipeline 4 is expelled to the other end B side as the tube 1 is expanded and crimped, and is discharged to the outside.

When the tube 1 is expanded one after another, a force as shown by the arrow in FIG. 7 acts on each band 2 that suppresses the rearward force, and the band breaks at the notch 3. When an adhesive tape containing fibers in the vertical and horizontal directions is used as the band 2, its characteristic is that the tensile strength in the longitudinal direction of the tape is large, but when a tearing force is applied to the notch 3 in the direction of the arrow as shown in Fig. 7, the force is relatively small. This adhesive tape 2 has the property of breaking when the tube (lining) 1 is broken easily and smoothly.
Since it is sufficiently thin compared to the thickness of the lining, there will be no functional problem even if it is left as is between the inner surface of the pipeline and the inner surface of the pipeline.

The crimping between the tube 1 and the inner surface of the pipeline 4 is at the end (sixth
When the tube 1 reaches the left end in the figure), cut the tube 1 at the desired length, spread the end in a ratchet shape, and press it against the surface of the flange 5B as in the case of the starting end. ) to keep it airtight.

This completes the lining of the inner surface of the tube.

According to the embodiment described above, the following actions and effects can be obtained.

(1) First, the lining material and its thickness can be selected to be strong enough to withstand and recover against external forces acting on the lining from transport fluids, pipelines, etc., resulting in the following advantages: It will be done.

(1) Even if there is a local lack of adhesion of the tube to the inner surface of the Hypline, this can be compensated for by the entire lining, which has resilience, so there is no need for severe pre-treatment like in the case of painting. , the construction period can be shortened accordingly. In the case of painting, the pretreatment is defective even locally;
Rust, scale.

If there is even a small amount of foreign matter, dew condensation, etc., the adhesion in that area will be poor and the coating will peel off, and this area will become a breakthrough and cause further corrosion and peeling. There are no problems.

(11) When the transport fluid' is a high-pressure gas, even if pressure fluctuations or negative pressure occur, the problem of lining separation does not occur. In the case of paint films, the film is thin, so gas permeates through the paint film and stays between the inner surface of the pipe and the paint film, which expands when the pressure is reduced, causing the paint film to peel off. In contrast, this embodiment does not have such a problem. That is, according to this embodiment, one is able to freely select a tube with sufficient thickness to prevent gas from penetrating, and second, a fluid adhesive is interposed between the tube and the inner surface of the tube. When high-pressure gas pressure is applied, this adhesive also presses the tube inward with a pressure equal to the gas pressure, so high-pressure gas cannot penetrate the lining.

(iii) K to ensure pipeline durability
The lining thickness can be freely selected depending on the desired durability. In the case of painting, the thickness of one coating is about 0.1r! l) In order to form a film thickness of 2.011111 or more, it is necessary to apply the coating many times, which requires a long construction period. In this embodiment, any thickness of lining can be formed at once, and the construction period can be shortened.

(lv) In this embodiment, a covering having a uniform thickness can be formed. Since the tube forming the lining is manufactured in a factory, its thickness can be easily controlled and checked. On the other hand, in the case of painting, variations in thickness tend to occur, and the coating film becomes thinner, especially at the protruding parts of the Uranami welds at the welded joints of steel pipes, which becomes a weak point in Tsukuibrine corrosion protection.

(2) According to this embodiment, the on-site construction is easier and requires less equipment than the Vig painting. 1. Pressing the tube against the inner surface of the tube. This can be done simply by supplying air or pressurized water. Lining (
Since a considerable load is applied to the tube (tube), the lining thickness is increased accordingly, and pressure is applied to the inner surface of the tube using Vig pressure feeding to completely expel air between the inner surface of the tube and the tube and increase the adhesive strength between the two. There is also a need to improve.

Even in this case, it is only necessary to prepare the pig and its pumping device. Additionally, in the case of submarine pipelines, using pressurized water to pressurize the lining can prevent the pipeline from floating due to its weight, which has the advantage of eliminating the need for a weight to sink the pipeline.

(3) Furthermore, when attaching a branch pipe to a pipeline and forming a coating inside the branch pipe, it is possible to line the pipe more easily and reliably by adopting the procedure described below with respect to Figs. 8 to 11. can.

(1) 40 main pipelines, as shown in Figure @8,
Branch pipes 10 having flanges 9 are connected by welding. The inner diameter d and length t of the branch pipe 10 are d > 100 wm in order to facilitate the following lining work.

It is preferable to select t=150m to 300%.

(11) Branch pipe 1 of main pipe lining (tube) 1
Cut and remove the part that touches the inner edge of 0 with a knife.

(1) A branch pipe tube 11 as shown in FIG. 9 is manufactured in advance. The material of this branch tube 11 is a highly elastic rubber-like elastic body similar to that of the main tube 1, and the outer diameter of this branch tube is equal to the inner diameter d of the branch tube 10, and the length of the branch tube is the same as that of the main tube 1. 7 lange folding allowance ( than the length t of
(adhesion allowance) or longer. A collar 12 is formed at one end of the branch pipe tube 11 (the end on the side that contacts the inside of the main pipe). The height of this collar 12 should be about 10 mm. The branch pipe tube 11 as described above is shown in FIGS. 10 and 11.
As shown in the figure, following the case of the main tube 1 described above, after being flattened and tightly attached, it is bent into a U-shaped or spiral cross section.
The adhesive tape 13 is wrapped to suppress the restoring force to the circular cross section. In the illustrated example, adhesive tape 13 is wound around two locations, and each adhesive tape has a notch 14 formed from its outer side edge.

Ov) Apply adhesive to the inner surface of the branch pipe 10 and the peripheral edge of the connection opening of the main tube 1 (the part where the collar 12 of the branch pipe tube 11 contacts). Branch pipe tube, 11
After applying adhesive to the outer surface of the tube and the contact surface of the collar 12, insert this branch pipe tube into the branch pipe IO so that the collar 12 at the tip touches the opening periphery of the main tube 1.
do.

・I(V) Next, the branch pipe 10 and the branch pipe tube 11
A knife is inserted between the two to break the adhesive tape 13 closer to the main tube (closer to the boxwood 12), returning the area near the brim 12 to a circular cross section. In this way, the collar 12 is brought into contact with the inner surface of the main tube 1, and after confirming this contact, the adhesive tape 13 on the front side is broken. Insert your hand or a stick into the branch pipe tube 11 to remove the inner surface of the branch pipe tube 11 and the boxwood portion 12.
Press evenly to adhere.

(Xun) The outer end of the branch pipe tube 11, that is, the branch pipe 10
The end protruding into the 7 flange 9@ is bent and adhered and fixed to the flange 90 surface.

(4) The tube (lining) 1 that coats the inner surface of the pipeline 4 is made flat and tightly adhered, and then bent into a U-shaped cross section as shown in Figure 3, so that the tube (lining) 1 is approximately half of its original diameter.
diameter. Also, after flat contact, the fourth
The diameter can be further reduced by bending it into a spiral cross section as shown in the figure.

If the pipeline has many bends, it is preferable to bend the spiral cross section as described above and make the diameter as small as possible before inserting it into the pipeline. In this case, each band (
It is preferable that the notch 3 of the adhesive tape 2 is formed at a stepped portion 15 at the outer end of the overlap shown in FIG.

Although the present invention has been specifically described above with reference to preferred embodiments, the present invention can be widely applied to slurry piping, corrosion-resistant piping, and other various pipelines that require low fluid resistance. Furthermore, the pipeline may be straight or curved in one or more arbitrary positions and in any direction, and can be widely applied to these.

As is clear from the above description, according to the present invention, a method for lining the inner surface of a pipe can be obtained which can form an inner surface coating with excellent workability and reliability.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view illustrating the tube (lining) used in the implementation of the present invention, Fig. 2 is a cross-sectional view illustrating the tube (lining) in Fig. 1 in a flat and close contact state, and Fig. 3 is the one in Fig. 2. U
4 is a cross-sectional view illustrating a tube bent into a U-shaped cross section; FIG. 4 is a cross-sectional view illustrating a tube bent into a spiral cross section from the one in FIG. FIG. 6 is a partial perspective view illustrating a state in which the band is wrapped; FIG. 6 is a longitudinal cross-sectional view illustrating a state in which the tube is fixed to the pipeline at the insertion start end after the tube is inserted into the pipeline; FIG. 7 is a partial perspective view for explaining how a band wrapped around a tube is broken inside a pipeline, FIG. 8 is a cross-sectional view illustrating a state in which a branch pipe is connected to a pipeline, and FIG. 10 is a side view illustrating the state in which the tube of FIG. 9 is flattened, bent and wrapped with a band; FIG. 11 is a longitudinal cross-sectional view illustrating a tube for branch pipe; FIG. DESCRIPTION OF SYMBOLS 1... Tube (lining), 2... Band (adhesive tape), 3... Notch, 4... Pipeline, 6... Wire, 10... Branch pipe, 11... Tube for branch pipe. Agent Tatsuyuki Unuma (and 2 others) Miko Miyohira z3 Figures 3 and 4t

Claims (6)

[Claims] (1) The step of sequentially flattening and tightly fitting a rubber-like elastic tube with an outer diameter equivalent to the inner diameter of the tube from one end, and bending this flat tube into a U-shaped or spiral cross section and attaching a sticky fluid to the outer surface of the tube. and wrapping bands at appropriate intervals in the longitudinal direction to suppress the restoring force to the circular cross section of the tube, and this band wrapping is performed by wrapping the tube from one end of a welded pipe such as a pipeline to another. a step of inserting the tube into the end; and a step of wrapping the band by force-feeding air or a pig into the tube to break the band and sequentially returning the tube to a circular cross section and crimping it onto the inner surface of the tube from the force. A method for lining the inner surface of a tube, comprising: forming a tube inner surface coating layer on the tube. (2) The method for lining the inner surface of a tube according to claim 1, characterized in that adhesive tapes are used as the bands, and each adhesive tape is provided with notches in the same direction. (3) In the band wrapping, when inserting the tube into a long tube, the tube is coupled to a wire that has been passed through the tube in advance, and the wire is pulled into the tube. Or the tube inner surface lining method described in item 2. (4) The tube is made slightly longer than the long tube, and both ends of the tube after insertion are fixed under pressure to the surfaces of flanges provided at both ends of the long tube. 3. The method for inning an inner surface of a tube according to any one of items 1 to 3. (5) After completing band winding of the flat tube,
5. A method for lining the inner surface of a tube according to any one of claims 1 to 4, characterized in that a liquid sealing material is applied to the inner surface of both ends and crimped to prevent air from entering the tube. (6) A method for lining an inner surface of a tube according to any one of claims 1 to 5, characterized in that a corrosion-resistant grease is used as the sticky fluid applied to the outer surface of the tube.