JPH0375266B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pipe end and a joint, and furthermore, if a terminal device is welded to the end of a long pipe whose inside is coated with corrosion-resistant coating, the corrosion-resistant material This invention relates to a method for attaching an end member such as a flange to the end of the long pipe under conditions where the pipe deteriorates.

When laying pipelines for transporting petroleum, petroleum products and petrochemical products, the pipelines must be of standard length,
It is usually made by welding together 12 m (40 ft) of pipe. Typical pipes for this pipeline are steel pipes coated or lined with a corrosion-resistant plastic material. High engineering efforts have resulted in plastic materials that have the corrosion resistance required by the petrochemical industry and can be suitably applied to the surface of the steel pipes. To coat the inner surface of the steel pipe with this specially developed plastic material, it is applied several times in a coating shop, and after each application, the coated area is heated and dried in a high-temperature oven. The oven is controlled to properly cure the paint coating. The long pipes painted in this way are sent to the construction site and assembled into pipelines.

There are many methods for connecting the painted long pipes, but the widely used method is to butt the ends of the pipes together and weld the periphery. The problem when welding pipes whose inner surfaces are coated with plastic is that the coating burns due to the heat of welding, and
or scorching, so that the corrosion resistance of the inner surface of the tube is lost or significantly reduced.

Special connection methods have been developed to solve the problem of burning of the plastic coating layer on the inner surface of the tube. Among them, N.
1970 by NW Kessler et al.
This is a welding method disclosed in U.S. Pat. This method uses a metal sleeve whose inner surface is coated with a corrosion-resistant plastic material and heat-dried, the long end is shaped like a bell, the bell-shaped end is placed over the sleeve, and the sleeve is butted. The butt portions are welded to connect. A heat insulating material such as asbestos is wrapped approximately in the center of the outer surface of the metal sleeve, just inside the butt of the tube. The end of the metal sleeve is tapered and a packing device, such as an O-ring, is provided to provide a seal between the sleeve and the inner surface of the tube. To reinforce this seal,
Before inserting the sleeve into the tube, an uncured thermoset corrosion-resistant material is applied to the end of the sleeve and to the inner surface of the end of the tube. Thereafter, the peripheries of the butted ends of the tubes are welded.

The ends of the pipeline connected by the above-mentioned welds must be connected to something other than the pipeline, such as a storage tank, a T-joint, a Y-joint, etc. The length of the pipe at this pipeline connection is typically shorter than the standard pipe length of 12 m (40 ft). Since the above-mentioned terminal section is made at the construction site and the terminal section is generally joined by a flange, the flange can be attached to the end of the pipe without reducing the corrosion resistance of the end of the pipe that makes up the pipeline. The equipment and methods for this must be easy to use by welders in the field.

A conventional painted standard pipe is cut to the required length, and a tubular flange is welded to the end of the cut pipe, and then the above-mentioned pipe is welded using a welding device based on the patent of Kessler et al. was connected to the line. As an alternative, painting the inner surfaces of short pipes of different lengths and heating and drying them can be done in a painting factory (this results in a better quality paint film), and the welders at the construction site can use the painted short pipes mentioned above. Another method is to have pipes, so-called dog-eared pipes, be used to install pipelines. In this installation work, a tube end flange is welded to one end of the dog-eared tube, and the other end is welded to the pipeline using the method disclosed in the patent.

In either of the above two methods, the good corrosion-resistant coating on the inner surface of the tube burns or scorches when the flange is welded to the end of the tube. Conventionally, an air-drying plastic patch was applied to the burnt part of the inner surface of the short tube. This method is not completely satisfactory. This is because the natural drying plastic materials available today are inferior in corrosion resistance to the above-mentioned heat-dried plastic materials, and
This is because the above-mentioned air-drying type patching material often does not adhere to the metal parts inside the pipe or the heat-dried parts, or does not have enough corrosion resistance to withstand a highly corrosive environment.

In addition to the methods mentioned above, methods that do not damage the coating on the inner surface of the end of the pipeline include using a pipe with a flange attached, or using a plastic insertion member on the flanged end of a shortened pipe. There is a way to do it. A similar insertion member is also provided on the other flange. These two plastic insertion members are sandwiched and fixed between the flanges that were fitted together when connecting the above pipes, and the joining part of the flanges is covered with something like a plastic backing material so that there is no gap at the joint. However, good results are not always achieved, since the plastic insert may be damaged during this joining operation. On the other hand, if the insertion member attached to the flange is made of strong and durable plastic, it often has poor adhesion to the air-drying backing material.

An object of the present invention is to provide an apparatus and method that can perform end treatment to attach a flange without damaging the high-quality corrosion-resistant coating on the inner surface of the end of the tube.

A second object of the present invention is to provide an apparatus and method that allow a welder working on pipeline construction to easily and economically attach a flange to a pipe and perform terminal treatment at the construction site.

A third object of the present invention is to provide an apparatus and method for terminal treatment of connecting pipes with good corrosion resistance without using flanges.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall view of the end portion of the tube 10, to which the flange is attached. The pipe 10 is for pipeline use and may be any type of pipe having a diameter from 152.4 mm (6 inches) to 1219.2 mm (48 inches).
The inner surface of the tube 10 is coated 1 with a corrosion-resistant plastic material.
1, and this coating 11 is applied and heat-dried at a pipe coating factory. This coating 11 is manufactured by, for example, AMF Scope Co., Ltd. (AMF) located in Hyuston, Texas, USA.
It may be any of the phenolic, epoxy, or urethane-based plastic materials known as Tube Kote, which are formed in the Tuboscope Inc. paint shop. The above application is carried out two or more times by heating a liquid plastic material and spraying it over the entire surface of the tube, or by heating a powdered plastic material and sprinkling it on the inside of the tube.
Each application is heated and dried in an oven until hardened in the case of liquid plastics or melted and hardened in the case of powdered plastics. This plastic coating is shown in FIG. 1, the thickness of which is exaggerated for illustration purposes.

A commercially available flange 14 having an annular welding neck is butt welded to the right end of the pipe 10 coated as described above. This welding is similar to the conventional standard welding method, with two
This is done by applying beads more than once. In addition, as with the conventional standard connection method, the flange 14
Drill a vertical hole 16 in the hole, pass a bolt through this hole 16,
These bolts tightly connect the flange 14 and the opposing flange to prevent leakage of the fluid to be transported. A metal sleeve-shaped insertion tool 20 is disposed within and coaxially with this flange 14, and the right end 15 of this insertion tool 20 is firmly fixed to the flange 14 by welding. The left end of this insertion tool 20 is roundly recessed inward, and a taper 22 is machined on the outside of the left end. A narrow annular groove 24 is provided on the cylindrical body of the insertion tool 20 at the base of the tapered portion 22, and a sealing device such as a resilient O-ring 28 is installed in the groove 24. . A wide groove 30 is provided on the entire outer periphery of the central part of the sleeve-shaped insertion device 20, and a heat insulating material 32 such as asbestos tape is wrapped several times so as to substantially fill the groove 30.

A high-quality continuous coating 40 of corrosion-resistant plastic material is applied in a paint shop and heated to dry, starting from the connecting surface 42 of the flange 14 and extending over the sleeve-shaped insert. 20 and the tapered surface 22 to form an annular groove 30 in the center of the sleeve-shaped insert 20.
The range extends to the outer surface of the vicinity of . A sealant 44 made of an epoxy-based corrosion-resistant plastic material is applied around the painted surface of the tapered portion 22 of the sleeve-shaped insert 20 and the painted inner surface 11 of the tube 10.

Thermal insulation material 32 is wound in multiple layers around the annular groove 30.
is located directly below the abutting ends of the tube 10 and the flange 14, and prevents heat from being transferred to the sleeve-shaped insert 20 during welding, and this insulation effect prevents the plastic on the inner surface of the sleeve-shaped insert 20 from being transmitted to the sleeve-shaped insert 20. Prevents burning or scorching of the coating 40 during welding. A similar structure is disclosed in the aforementioned US Pat. No. 3,508,766.

Welding of the flange 14 of the sleeve-shaped insert 20 and painting of the welded portion are carried out at a reception factory and a painting factory, and the work is carried out before shipping to the pipeline installation site. This way, the painting can be done under controlled conditions in the paint shop,
A high-quality corrosion-resistant coating can be produced by curing, that is, heating and drying. For example, the tapered end 2 in FIG.
2. Insertion tool 20 provided with grooves 24 and 30
must be made by machining steel pipes of the same grade as the steel pipes for the pipelines mentioned above. Do not paint yet at this stage. The flange 14 for forming the end portion of the tube 10 is attached to the right end of the insertion tool 20. The procedure for attaching the flange 14 is to hold the flange 14 until the joint end embedding 50 of the flange 14 comes to approximately the center of the groove 30. The method is to push it in. Second
As shown, the inner surface of the flange 14 should substantially contact the outer surface of the sleeve-shaped insert. Next, the flange 14 is welded and fixed around the right end of the sleeve-shaped insertion tool 20, and the joining surface 42 of the flange 14 is made flat by machining, and the inner right corner 5 of the sleeve-shaped insertion tool 20 is
Round the sharp edges of number 8. The coupling surface 42 of the flange 14, the entire inner surface of the sleeve-shaped insert 20, and the tapered end 22 are then connected to the annular groove 30.
A corrosion-resistant plastic material, such as the above-mentioned Tube Coat, is applied to the area up to the edges to improve the coating quality, and the assembled assembly is placed in a furnace under controlled conditions. The coating film is cured by heating and drying it. This procedure is exactly the same as for the pipeline pipe described above.

After performing the above-described processing, the component assembly shown in FIG. 2 is shipped to the construction site, and the subsequent steps are performed by a welder at the construction site. A welder at the construction site aligns the component assembly shown in FIG. 2 with the right end of the pipeline pipe 10, lightly chamfers the outer surface 62 of this part, and then applies thermosetting plastic sealant 44 to the pipe. It is applied in a band shape to the inner surface of the end of the insertion tool 20, and also applied to the range from the tapered part 22 to the groove 30 on the outer surface of the insertion tool 20. What you should be careful about when working at this construction site is to apply the sealant 44 to the two locations without any breaks;
The coating operation should not be interrupted even on holidays, and the tube 10 should be stored so that the vicinity of the end of the tube 10 is not contaminated in a manner that would have a detrimental effect on welding. As the above sealant
A suitable sealant is sold by AMF Tuboscope under the trade name Thru-Kote sealant. Next, the O-ring 28 of the groove 24 is attached, the groove 30 is wrapped with asbestos tape, and the tapered end of the sleeve-shaped insertion device 20 is forcibly inserted into the open end of the tube 10. The right end of is the innermost part 50 of the flange 14.
Insert until it is 1.6 mm (1/16 inch) from In this way, the flange and the end of the tube will be in a suitable position for welding the outer peripheries of these two parts. This outer circumferential welding, like normal welding, must be repeated many times before finishing.
Additionally, as disclosed in the Kessler et al. patent, the initial welding may cause the welding gas to blow out from the O-ring 28 and cause the O-ring 28 to
In order to allow the welding gas to escape from the vent hole without breaking the seal formed by the sealant 44 and the sealant 44, the welding is performed in at least two stages. Said tube 10
and the left end of the flange 14, ensuring that the weld is directly above the asbestos-wrapped portion 32, so that the plastic on the inner surface of the sleeve-shaped insert 20 is removed from this weld. The heat transmitted to the coating film 40 is suppressed to a minimum to prevent the coating film from burning. Therefore, no deterioration damage is caused to the excellent corrosion resistance properties of the heat-dried coating film.

The flanged terminal shown in FIGS. 1 and 2 is a preferred embodiment of the present invention, and the method invention is not limited to this type of terminal. FIGS. 3, 4, and 5 show simplified shapes of end members of known tubes of other types than those described above, and the metal sleeve-shaped insert 20 may also be used for these end members. can be used in substantially the same manner as described above. For example, FIG. 3 shows a combination of the metal sleeve-type insert 20 and a Victor-type pipe joint, and FIG. 4 shows the combination of the sleeve-type insert 20 and the Victor-type pipe joint.
FIG. 5 shows a combination of the sleeve type insert 20 and a standard female threaded fitting. As can be seen in FIGS. 3-5, the joint ends of each of the joints are located approximately in the center of the annular groove 30, just as in FIGS. 1 and 2. The process of painting the inner surface of the assembly shown in FIGS. 3 to 5 is the same as that shown in FIGS. 1 and 2, and the sleeve-shaped insert shown in FIGS. 3 to 5 is inserted into the end of the tube. The procedure for doing this is also substantially the same as in the case of FIGS. 1 and 2.

Although preferred embodiments of the present invention have been described above with reference to the drawings, these embodiments may be replaced or improved within the scope of the claims of the present application.

[Brief explanation of drawings]

1 is a sectional view of the end of a tube according to the invention; FIG. 2 is a sectional view of a sleeve-shaped insert and flange assembly used in the end of the tube of FIG. 1; FIGS. FIG. 5 shows another type of tube end assembly. 10... Pipe, 11... Corrosion-resistant coating film, 13... Welding bead, 14... Flange, 16... Hole for flange connection, 20... Metal sleeve-shaped insertion tool,
22... Tapered portion on the outer surface of the insertion tool, 24... Concave portion, 28... O-ring, 30... Groove, 32... Heat insulating material, 40... Paint film, 42... Flange joint surface,
44... Sealant, 62... Chamfered portion.

Claims (1)

[Claims] 1. A method for fixing a terminal member to the end of a tube whose inner surface is coated with a corrosion-resistant coating that is likely to deteriorate due to heating, the method having an annular groove on the outer surface near the center. placing the terminal member over one end of the sleeve-shaped insertion tool; aligning the joining end of the terminal member with the annular groove; placing the terminal member over the sleeve-shaped insertion tool; fixing; applying a corrosion-resistant coating to the inner surface of the sleeve-shaped insert and the entire surface of the end member that comes into contact with fluid when passing it through the tube;
substantially filling the annular groove with a heat insulating material;
applying a sealant to the end of the insert and/or the tube; inserting the sleeve insert into an end of the tube having an inner diameter sufficient to receive the sleeve insert; pushing the sleeve-shaped insert so that the end wall of the upper tube and the joining end of the terminal member abut against each other directly above the heat insulating material; abutting against the joining end of the terminal member; A method for terminal processing a pipe, comprising the step of welding the periphery of the end of the pipe to connect the two parts together. 2. In a method for manufacturing a component assembly for end treatment, which is used by being fixed to the end of a pipe whose inner surface is coated with a corrosion-resistant coating that may deteriorate due to heating, placing a tube end member over one end of an annular metal sleeve-shaped insert having an annular groove; aligning a mating end of the end member with the annular groove;
fixing the terminal member to the sleeve-shaped insert; applying a corrosion-resistant plastic material to the inner surface of the sleeve-shaped insert and the entire surface of the terminal member that comes into contact with fluid when flowing through the tube; A component assembly for pipe end treatment comprising the steps of applying and coating the same; and curing the corrosion-resistant plastic coating by heating the component assembly in a furnace. How to manufacture. 3. When welding an end flange to a pipe whose inner surface is coated with a corrosion-resistant plastic material, the corrosion-resistant coating may be deteriorated or damaged by the heat generated when welding the end flange to the pipe. In the terminal processing method, a step of assembling an annular tube end flange so as to cover one end of a metal tubular insert having an annular groove on the outer periphery between both ends; aligning a mating end of a flange with the annular groove; welding the terminal flange to the metal tubular insert to form a component assembly; flowing fluid through the tube; coating the inner surface of the metal tubular insert and all surfaces of the terminal flange, which are sometimes in contact with the fluid, with a corrosion-resistant plastic material; the coated metal tubular insert; curing the corrosion-resistant plastic coating by heating the flange in a furnace; substantially filling grooves in the outer surface of the metal tubular insert with insulation material; applying a sealing member comprising a sealant to an end of the device opposite the flange; inserting the metal tubular insert into the open end of the tube so that the end wall of the tube and the pushing the insert so that the joint end of the terminal flange and the butt position are directly above the heat insulating material; welding the end of the pipe and the joint end of the terminal flange; A method for treating the end of a pipe, comprising the step of integrating the two parts so that no fluid leakage occurs between the two parts. 4. A metal annular end flange with a joint surface at one end and the opposite end; and a metal annular sleeve having an annular groove extending in the axial direction on its outer surface. a component assembly for end treatment of a pipe, characterized in that the joint end of the flange on the side of the pipe to be joined is located above the groove of the sleeve and the relative arrangement thereof; 5. Claim 4, characterized in that a corrosion-resistant plastic coating is continuously applied to the entire inner surface of the sleeve and the joint surface of the flange, and the coating is cured by heating and drying. Component assembly for pipe end treatment. 6 an annular groove provided on the outer surface of a portion of the sleeve adjacent to the end opposite to the welded portion; a tapered portion provided on the outer surface of the opposite end of the sleeve; The tube according to claim 5, characterized in that it is combined with the tapered end on the opposite side from the inner surface and the corrosion-resistant plastic coating that is uniformly applied over the groove and cured by heating. Component assembly for terminal processing. 7. The component assembly for pipe end treatment according to claim 6, characterized in that a sealing device provided in the convex portion and a heat insulating device provided in the groove are combined. 8. Abutting the joint end of the flange and the end of the pipe at a position directly above the heat insulating material, inserting the sleeve into the end of the pipe, and connecting the end of the pipe to the flange. 8. The component assembly for pipe end treatment according to claim 7, characterized in that the component assembly is combined with holding at the joint end of the pipe.