Method and device for inner corrosion protection of weld joint zone

FIELD: construction.

SUBSTANCE: device comprises the assembling-arresting unit which locks the bushing against self-unscrewing. The bushing is provided with a heat insulating material and sealing composition and is made of the self-unscrewing spring, which accumulates mechanical energy. The inner end of the spiral belt is provided with a blade, which is mounted in the vicinity of the face edge of the inner end of the belt and the ends of which are provided with guiding projections. The method comprises setting the assembling-locking unit with the bushing on the pipe end to be welded, assembling the pipe butt by moving the end of the pipe to be welded onto the projections of the bushing and heat insulating material to provide a gap between the pipe faces, unlocking the bushing, and removing the assembling-locking unit. The spiral belt is unwound with sliding with respect to the inner end. The gap size depends on the thickness of the assembling-locking unit. The projections of the blade cooperate with the side edges of the belt turns and cause the sealing composition to move thus providing a protecting roll.

EFFECT: enhanced reliability of the pipeline.

3 cl, 6 dwg

 

The invention relates to the field of manufacturing and installation of pipelines internal corrosion-resistant coating and can be used for corrosion protection of internal surfaces of the zones of welded joints in the manufacture of pipe sections of a pipe having an internal coating along the length, but the ends, when mounting the trunk, field and other pipelines intended for transportation of crude oil, produced water, gas, oil, water and other environments of the pipe sections or individual tubes.

The known method and device for internal corrosion protection zone of a welded joint of pipe having an internal corrosion-resistant coating on its entire length, but the ends of the pipes (RF patent No. 2080510, CL F 16 L 13/02, the application 95108103/06 from 18.05.95, published 27.05.97, authors: V.A. Kazakov, Kolesne SV, Sytin, H.E., Canasuc NI). The device comprises a hard metal sleeve with a constant diameter, having a corrosion-resistant coating, equipped with a sealing composition, an exterior grooves in its ends is placed an o-ring. In the Central part of the sleeve on its outer surface a groove in which is placed a heat insulating material, designed to protect temperature-sensitive elements of the node set from damaging high temperatures occur in the soup during welding of the pipe joint. The device has a system that secures its position in the pipe joint. Before placing the device in the cavity of the pipe joint to certain portions of the inner surfaces of the abutting ends of these pipes is applied sealant. The device is placed in the cavity abutting pipe ends during Assembly of the welding joint.

To obtain corrosion protection required quality when using this technical solution requires, on the one hand, the external diameter of the device would always be smaller than the inner diameter of the abutting pipe ends, and, on the other hand, so that when the coupling sleeve with the abutting ends of the pipes would not have taken place and an excessively large gap. However, normative deviation of geometric sizes and shapes all standard pipe such that it is not guaranteed the fulfillment of the conditions specified above. In addition, if we consider that there can be substantial random geometric errors of shape and size of the pipe ends, acquired in the process of loading, transporting, unloading and storage, the possibility of effective use of the known device that contains a hard sleeve with a constant diameter, to obtain corrosion protection required quality becomes problematic.

It is desirable to have a method and apparatus for internal protivoga rosinei protection zone of welded pipe connections, to compensate for possible deviations of the geometrical sizes and shapes of the inner surfaces of the ends of the adjacent pipes.

The known method and device for internal corrosion protection zone of a welded joint of pipe having an internal corrosion-resistant coating on its entire length, but the ends of the pipes developed by the company “Tuboscope Vetco International (USA), which was shown at the 10th international exhibition “Oil and gas” in Moscow in July 2001 (see promotional materials company, as well as United States Patent, Patent Number: 4,913,465; Date of Patent Apr. 3, 1990; Inventors: William D. Abbema, J. Casey Jones; Assignee: Tuboscope Inc., Houston, Tex.; Appl. No. 235, 457; Filed: Aug. 24, 1988). The device comprises a hard metal sleeve with a constant diameter, having a corrosion-resistant coating, equipped with a sealing composition, an exterior grooves in its ends is placed an o-ring. In the Central part of the sleeve on its outer surface a groove, in which there is formed in the form of an annular zone heat insulating material designed to protect temperature-sensitive elements of the node set from damage by high temperatures that occur when welding pipes. The device has a system that secures its position in the pipe joint. Before placing the device in the cavity of the pipe joint on certain parts of the inner surfaces of the joint is controlled ends of these pipes is applied sealant. The device is placed in the cavity abutting pipe ends during Assembly of the welding joint. The shape and geometrical dimensions of the outer surfaces of the ends of the sleeve and the inner surfaces of the pipe ends carry out so that when they mate would place the required gap. To this end, taking into account the above possible deviations of the size and shape of pipe ends to the inner surface of the pipe ends prior to placement of the device being calibrated. The degree of accuracy should be such, which ensures the interchangeability of the elements of the connection.

The need to perform calibration of the internal surfaces of the pipe ends complicates the conditions for the use of the known method and device, and increases costs.

It is desirable to have a method and apparatus for internal corrosion protection zone of welded pipe joints to compensate for possible deviations of the geometrical sizes and shapes of the inner surfaces of the ends of adjacent pipes and to exclude the operation of the calibration, making it easier this way and reducing costs.

The known method and device for internal corrosion protection zone of a welded joint of pipe having an internal corrosion-resistant coating on its entire length, but the ends of the pipes (application 2001113021 dated may 16, 2001; 19.06.2001 - positive result of the formal examination; 12 the art 2002 - the decision on the grant of a patent. Authors: Zhdanov M.G., G.M. frost).

The device comprises a sleeve made of metal coiled ribbon of corrosion-resistant performance, representing amarasiriwardena spring, in which the estimated amount of accumulated mechanical energy, equipped with a pad impregnated with a sealing composition. The device comprises a heat insulating material, designed to protect temperature-sensitive elements of the node set from damage by high temperatures that occur during welding of the pipe joint, and a system that secures the tape from samorazvitiyu with deixarei. Fixed device is placed in the cavity of the pipe joint during Assembly of the welding joint, providing the clearance between the ends of adjacent pipes which carry out the subsequent dificatio coiled tape. After deixarei there is a partial samorazvitiya coiled ribbon attached to strip impregnated sealing composition, pressing her this strip and insulating material to certain portions of the inner surfaces of the abutting pipe ends and the implementation of these internal corrosion protection zone of welded pipe joints. Next, perform the welding joint troptraditions way. Partial samorazvitiya coiled ribbon of the known device is limited to the inner surfaces of the abutting pipe ends. The execution of the sleeve in the form of a coiled ribbon representing amarasiriwardena spring, considering the fact that the limiting factor partial samorazvitiyu every time are the specific internal surface of the abutting pipe ends that have specific regulatory and random deviations of geometric sizes and shapes, allows each time to compensate for these specific deviations and every time to get the desired pair in the “nut - abutting ends of the pipe”. Sealant, partially extruded in partial samorazvitiya tape, is formed in areas of the pair of end faces of the sleeve with the inner surfaces of the abutting pipe ends in the form of protective cushions, further increasing the tightness of corrosion protection in these places.

Specified known technical solution is the closest to the claimed combination of essential features and made for the prototype.

However, when using the known method and device, integrity and, as a consequence, the reliability of corrosion protection in place fit the inner end of the coiled tape and attached gasket, propiano the sealing composition, to conjugate this end vneshnesekretornoi the tape surface is insufficient. The reason for this is that when samorazvitiya coiled tape is proculture in the circumferential direction of the inner end of the coiled tape with its associated strip, impregnated sealing composition, relative to the conjugated vneshnesekretornoi the tape surface and the sliding part of the sealing composition is entrapped and taken from the above-mentioned space pairing, resulting in this place a deficit of sealing compound. In addition, when samorazvitiya coiled tape is an arbitrary offset its inner end in the axial direction close to the direction of the longitudinal axis of the pipeline) in one direction or another, which also affects the tightness of corrosion protection in place fit the inner end of the coiled tape to conjugate this end vneshnesekretornoi surface of the tape. The design of the system, fixing tape from samorazvitiyu with deixarei, in the known device determines the existence of the special holes in the tape and in other elements of the device, which reduces the reliability of corrosion protection.

Desirable is to have a method and apparatus for internal corrosion protection zone of welded pipe connections, do not have these disadvantages.

The problem is solved in that in the method of internal corrosion protection zone of welded pipe joints, which consists in placing before the connection pipe welding in the cavity of the pipe joint with the adjacent portions of the inner pipe coatings device containing a bushing made in the form of a metal strip of corrosion-resistant performance, coiled into a roll with the provision of external casediameter this roll of smaller internal diameter of the connected pipe, equipped with a sealing composition and representing amarasiriwardena spring, in which the estimated amount of accumulated mechanical energy, heat insulating material, designed to protect temperature-sensitive elements of the node set from damage by high temperatures arising when welding of the pipe joint, and a system that secures the tape from samorazvitiyu with deixarei, what's new is that in the device the inner end of the coiled tape is equipped podpisuvaus scraper, which is located near the end edges of the ends of the belt across its width, is rigidly connected with it, and has at the ends of the guides - borders, which communicates with both sides of the sleeve with the side edges vneshneporozhdaemyh VI the Cove coiled tape. System that secures the tape from smallportion with deixarei made in the form of articulated cloistered manage-stop site covering the tape and heat insulating material on the outside, with the possibility of deixarei by breaking articulated closed canopy Assembly and a locking knot. Before installing the unit into the cavity of the pipe joint to certain portions of the inner surfaces of the ends of adjacent pipes put sealant, install the fixed articulated closed Assembly and locking knot held with them by the sleeve and insulating material abutting the end of one of the pipes with the placement of this sleeve and insulating material part of their length in the cavity abutting the end of this pipe, coaxially with it, produce a coaxial Assembly of a pipe joint for welding by slipped on easily spliced the other end connected pipes protruding part of the sleeve and heat insulating material to form between the ends of the pipes gap, the minimum value of which is regulated articulated closed assembling and retaining node, perform dificatio tape by breaking articulated closed canopy Assembly retainer node with its subsequent destruction beyond the junction of the pipe and thus provide a partial samorazvitiya sleep the social coiled tape, causing slippage of the inner end of the coiled tape, equipped with a sealing composition, and rigidly connected with the end podpisovacieho scraper with guides-borders regarding paired with them vneshnesekretornoi the tape surface in the circumferential direction without displacement in the axial direction, which prevents guides-curbs, interacting with both ends of the sleeve with the side edges vneshneporozhdaemyh of turns of the coiled tape; podpisovanie scraper parts dragged and submitted, due to the aforementioned sliding, sealing compound in place of the pair of the inner end of the coiled tape with vneshnesekretornoi the surface of the tape in a direction close to perpendicular to the end edge of the inner the end of the tape to expiration, at the same time, excess podpisovacieho sealing composition of this place from both sides of the inner end of the coiled tape in the direction close to perpendicular to the side edges of the belt end; pressing with an estimated force parts sealing compound, equipping spirally rolled tape, to certain portions of the inner surfaces of the abutting pipe ends, including those of their plots, which before artelino was applied sealant; the pressing of the tape of insulating material to certain portions of the inner surfaces of the abutting pipe ends adjacent to the ends of the pipe, connecting pipe welding.

The problem is solved in that the device for internal corrosion protection zone of welded pipe joints containing sleeve, made in the form of a metal strip of corrosion-resistant performance, coiled into a roll with the provision of external casediameter this roll of smaller internal diameter of the connected pipe, equipped with a sealing composition and representing amarasiriwardena spring, in which the estimated amount of accumulated mechanical energy, heat insulating material, designed to protect temperature-sensitive elements of the node set from damage by high temperatures that occur during welding of the pipe joint, and a system that secures the tape from samorazvitiyu with deixarei, new is the fact that the inner end of the coiled tape is equipped podpisuvaus scraper, which is located near the end edges of the ends of the belt across its width, is rigidly connected with it, and has at the ends of the guides-borders, which communicates with both sides of the sleeve, with the side edges vneshneporozhdaemyh of turns of the spiral collapse is the tape. System that secures the tape from samorazvitiyu with deixarei made in the form of articulated closed canopy Assembly and locking of the site, covering the tape and heat insulating material on the outside, with the possibility of deixarei by breaking articulated closed canopy Assembly and a locking knot. Podpressdivname scraper with guides-borders at the ends can have different designs and shapes and, in the particular case, may be in the form of a segment of wire with bent ends, which are guides-borders.

The invention is illustrated by the graphic material, in which figure 1 shows the device placed part of its length in the inner cavity abutting the end of one of the pipes; figure 2 shows the cross section A-a in figure 1; figure 3 shows the position of the device in the cavity of the pipe joint to the point of breaking articulated closed canopy Assembly retainer node and its subsequent removal outside of the pipe joint; figure 4 shows the articulated Assembly and the locking node after its opening area of the pipe joint; figure 5 shows the cross section b-B in figure 4, which shows a pipe joint after removal of the articulated the Assembly of the locking unit; figure 6 presents the welded connection of pipes with internal corrosion protection.

The device which contains the sleeve, made in the form of coiled tape 1, equipped with a sealing composition 4, a heat insulating material 3 formed in the form of an annular belt, and articulated Assembly and the locking node 2. Connect the pipes 5 and 6 have an internal corrosion-resistant coating 7 and 8 along the entire length, but the ends of the pipes. Certain portions of the inner surfaces of the abutting ends of the pipes 5 and 6 applied sealant 15 and 16. Articulated Assembly and locking the node 2 includes a bracket-arm 11, the bracket-arm 12, the hinge 13 and the lock 14. Between the ends of the pipes 5 and 6 is formed of the gap 9. The inner end of the coiled tape 1 is equipped podpisuvaus scraper 17, which is rigidly connected with the inner end of the coiled tape 1. Podpressdivname scraper 17 is at the ends of the guides-borders 18. The sealing composition 4, which is equipped with a tape 1, and the sealant 15 and 16, previously applied to the inner surface of the abutting ends of the pipes 5 and 6, after partial samorazvitiyu coiled tape 1 fused among themselves, partly embossed tape 1 and formed protective rollers 10, further augmented by the excess sealing compound 4, expired on rollers 10 due podpisovacieho action of the scraper 17.

The method is as follows. Before us is a time device, certain portions of the inner surfaces of the abutting ends of the pipes 5 and 6, having an internal corrosion-resistant coating 7 and 8, is applied sealant 15 and 16. On the abutting end of one of the connected pipe 5 set recorded articulated closed Assembly and the locking node 2 held with them by the sleeve and the insulating material 3, with the placement of this sleeve and heat insulating material 3 a part of their length in the cavity abutting the end of the pipe 5. Based on the outer surface abutting the end of the pipe 5, articulated closed Assembly and the locking node 2 centers held their sleeve and a heat insulating material 3 in the cavity abutting the end of the pipe 5. The outer casediameter roll, in which a spirally coiled strip 1, are equipped with a sealing composition 4, substantially less than the internal diameter of the connected pipe 5, and 6, that allows to avoid when placing the device hit the sealing composition 4 on the edge and near the adjacent area of the inner surface abutting the end of the pipe 5 and the edge and near the adjacent area of the inner surface abutting the end of the pipe 6 (subsequent nadhani pipe 6 to the device). Produce a coaxial Assembly of the pipe joint 5 and 6 for welding by slipped on easily spliced the other end of the pipe 6 to perform the s part of the sleeve and heat insulating material 3 to form between the ends of the pipes 5 and 6 of the gap 9, minimum value which is regulated by the thickness of the radial elements staples-levers 11 and 12 of the articulated Assembly of the stopper node 2. Are dificatio coiled tape 1 by breaking articulated closed canopy Assembly retainer node 2 using the lock 14, attach the bracket to the lever 11 and the bracket-arm 12 angular movement around the hinge 13 and remove the articulated Assembly and the locking node 2 beyond the joint between the pipes 5 and 6. When opened, articulated node 2 and the angular movement of the staple-levers 11 and 12 around the hinge 13 occur defecate and partial samorazvitiya tape 1 through part accumulated in her mechanical energy, while the inner surface of the abutting ends of the pipes 5 and 6 restrict partial samorazvitiya tape 1. Partial samorazvitiya coiled tape 1 is slippage in the circumferential direction of its inner end and rigidly connected with him podpisovacieho scraper 17, having at the ends of the guides-curbs 18, relative to paired with them vneshnesekretornoi surface of the tape 1. When this slippage part carried and brought sealing compound 4 encounters an obstacle in the form of a scraper 17 and consequently force podrazdelyaetsya them in place with the Directive of the inner end of the coiled tape 1 with vneshnesekretornoi the surface of the tape 1 in the direction close to perpendicular to the end edge of the end, after the excess podpisovacieho sealing part 4 of this place from both sides of the inner end of the tape 1 in the direction close to perpendicular to the side edges of the end of the tape 1. Therefore, eliminated the deficit sealing compound 4 in the above-mentioned place mates and, consequently, achieves the required tightness corrosion protection and in this place. When slippage of the inner end amarasiriwardena coiled tape 1 in the circumferential direction prevents its displacement in the axial direction due to the fact that guides the borders 18 podpisovacieho scraper 17, interacting with the side edges vneshneporozhdaemyh of turns of the coiled tape 1, prevent such displacement of the inner end of the tape 1, which also positively affects the tightness of corrosion protection in place fit the inner end of the coiled tape 1 to conjugated vneshnesekretornoi surface of the tape 1. Partial samorazvitiya coiled tape 1 sealant 4, which is equipped with a tape 1, and the sealant 15 and 16, previously applied to the inner surface of the abutting ends of the pipes 5 and 6, Slivets settled between themselves and partially removed with the formation of the protective rollers 10, additionally replenished excess sealing compound 4, expiring due podpisovacieho action of the scraper 17. Tabs-curbs 18 podpisovacieho scraper 17 are thus encapsulated in a protective rollers 10. Possible polymerization of the sealant composition can be carried out with external heating of the junction of the 5 and 6 from an external source, but it can be carried without special heating based on the properties of the sealing means. Weld abutting ends of the pipes 5 and 6 according to the traditional technology, as performed internal corrosion protection zone of the pipe joint does not require it to change.

An example of a specific implementation of the device. Metal spirally coiled strip 1 is made of cold spring complex steel strip according to GOST 2283-79 thickness of 0.5 mm as a heat insulating material 3 used heat resistant tensile fiberglass special weave thickness of 3 mm as the sealing composition 4, which equip the tape 1, and a sealing compound 15 and 16, which is applied on the inner surface of the abutting ends of the pipes 5 and 6, used polymeric thixotropic (nesteia) composition based on epoxy resin. The metal strip 1 has a corrosion-resistant utverjdenie coating thickness of 0.5 mm on the basis of epoxy resin. Truboprovod, the weld joint which protects from the inside, made of pipes 5 and 6 welded steel according to GOST 20295-85. Internal corrosion-resistant coating 7 and 8 of these pipes is made on the basis of epoxy resin over the entire length, but the ends of the pipes. Nominal outer diameter of the pipe - 219 mm, wall thickness - 7 mm, an Outer transverse dimension of the device at 180 mm, length 240 mm

1. The way internal corrosion protection zone of welded pipe joints, which consists in placing before joining pipes by welding, in the cavity of the pipe joint with the adjacent portions of the inner pipe coatings device containing a bushing made in the form of a metal strip of corrosion-resistant performance, coiled into a roll with the provision of external casediameter this roll, the smaller the internal diameter of the connected pipe, equipped with a sealing composition and representing amarasiriwardena spring, in which the estimated amount of accumulated mechanical energy, heat insulating material, designed to protect temperature-sensitive elements of the node set from damage by high temperatures that occur during welding of the pipe joint and a system that secures the tape from samorazvitiyu with deixarei, characterized in that the inner end of the spirally rolled the th tape equipped podpisuvaus scraper, located near the end edges of the ends of the belt across its width, is rigidly connected with it, and has at the ends of the guides-borders, which communicates with both sides of the sleeve, with the side edges vneshneporozhdaemyh of turns of the coiled tape, and the system that secures the tape from samorazvitiyu with deixarei made in the form of articulated cloistered manage-stop site covering the tape and heat insulating material on the outside, with the possibility of deixarei by breaking articulated closed canopy Assembly and locking of the site before installing the unit into the cavity of the pipe joint to certain portions of the inner surfaces the ends of adjacent pipes put sealant, install the fixed articulated closed Assembly and locking knot held with them by the sleeve and insulating material abutting the end of one of the pipes with the placement of this sleeve and insulating material part of their length in the cavity abutting the end of this pipe, coaxially with it, produce a coaxial Assembly of a pipe joint for welding by slipped on easily spliced the other end connected pipes protruding part of the sleeve and heat insulating material to form between the ends of the pipes gap, minimum value which reglamentary the tsya articulated with the Assembly and locking knot, are dificatio tape by breaking articulated closed canopy Assembly retainer node with its subsequent destruction beyond the junction of the pipe and thus provide a partial samorazvitiya coiled tape, causing slippage of the inner end of the coiled tape, equipped with a sealing composition, and rigidly associated podpisovacieho scraper with guides-borders regarding paired with them vneshnesekretornoi the tape surface in the circumferential direction without displacement in the axial direction, which prevents guides-curbs, interacting with both ends of the sleeve with the side edges vneshneporozhdaemyh of turns of the coiled tape, podpisovanie scraper parts dragged and viable due to the aforementioned sliding, sealing compound in place of the pair of the inner end of the coiled tape with vneshnesekretornoi the surface of the tape in a direction close to perpendicular to the end edge of the inner end of the tape, after the excess podpisovacieho sealing composition of this place from both sides of the inner end of the coiled tape in the direction close to perpendicular to the side edges of the belt end, when atie with an estimated force parts sealing compound, equipping spirally rolled tape, to certain portions of the inner surfaces of the abutting pipe ends, including those of their plots, which was previously applied sealant, pressure tape of insulating material to certain portions of the inner surfaces of the abutting pipe ends adjacent to the ends of the pipe, connecting pipe welding.

2. Device for internal corrosion protection zone of welded pipe joints containing sleeve, made in the form of a metal strip of corrosion-resistant performance, coiled into a roll with the provision of external casediameter this roll, the smaller the internal diameter of the connected pipe, equipped with a sealing composition and representing amarasiriwardena spring, in which the estimated amount of accumulated mechanical energy, heat insulating material, designed to protect temperature-sensitive elements of the node set from damage by high temperatures that occur during welding of the pipe joint, and a system that secures the tape from samorazvitiyu with deixarei, characterized in that the inner end of the coiled tape equipped podpisuvaus scraper, which is located near the end edges of the ends of the belt across its width, rigidly with azan and has at the ends of the guides-borders, communicates with both sides of the sleeve, with the side edges vneshneporozhdaemyh of turns of the coiled tape, and the system that secures the tape from samorazvitiyu with deixarei made in the form of articulated closed canopy Assembly and locking of the site, covering the tape and heat insulating material on the outside, with the possibility of deixarei by breaking articulated closed canopy Assembly and locking of the node.

3. The device according to claim 2, characterized in that podpressdivname scraper with guides-borders at the ends made in the form of a segment of wire with bent ends.



 

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FIELD: construction.

SUBSTANCE: device comprises the assembling-arresting unit which locks the bushing against self-unscrewing. The bushing is provided with a heat insulating material and sealing composition and is made of the self-unscrewing spring, which accumulates mechanical energy. The inner end of the spiral belt is provided with a blade, which is mounted in the vicinity of the face edge of the inner end of the belt and the ends of which are provided with guiding projections. The method comprises setting the assembling-locking unit with the bushing on the pipe end to be welded, assembling the pipe butt by moving the end of the pipe to be welded onto the projections of the bushing and heat insulating material to provide a gap between the pipe faces, unlocking the bushing, and removing the assembling-locking unit. The spiral belt is unwound with sliding with respect to the inner end. The gap size depends on the thickness of the assembling-locking unit. The projections of the blade cooperate with the side edges of the belt turns and cause the sealing composition to move thus providing a protecting roll.

EFFECT: enhanced reliability of the pipeline.

3 cl, 6 dwg

FIELD: corrosion prevention technologies.

SUBSTANCE: method includes serial application of layers of polymer compositions to metallic surface, while serial layers of polymer compositions are made with various thermal expansion coefficients. As said polymer composition polyurethane compound is used with special admixtures and filling agent, influencing thermal expansion coefficient of covering layer, and content of said filling agent in each following layer is set less than content of said filling agent in previous layer.

EFFECT: higher efficiency.

2 cl, 9 ex

FIELD: construction.

SUBSTANCE: protecting coating comprises several layers. One of the layers is made of an elastomer. The elastomeric sealing layer is made of a calendered raw rubber which is protected with the fiber glass fabric from both sides. The fiber glass fabric is impregnated with phenol-formaldehyde resin with subsequent solidifying and vulcanizing the rubber.

EFFECT: enhanced reliability.

1ex

FIELD: construction.

SUBSTANCE: method comprises removing the exhaust insulation from the pipeline, preparing the outer side, applying the primer coat, and winding belt coating made of oil polymer. The belt coating is reinforced with glass net.

EFFECT: enhanced reliability.

FIELD: pipeline transport.

SUBSTANCE: method comprises fusing corrosion-resisting metal on the zone of the inner surface directly adjacent to the faces of pipes, lining the inner surface of the pipe ends including the surface of the fusing by adhesion coating made of heat-resistant corrosion-resisting material, applying anticorrosion coating on the inner surface of pipes including the surface of lining, and joining pipes by welding. The adhesive coating made of the heat-resistant corrosion-resistant material is made by gas-thermal spraying of the corrosion-resistive metal.

EFFECT: enhanced reliability.

1 cl, 2 dwg

FIELD: protection of metals against corrosion; protection of extended underground gas lines against corrosion.

SUBSTANCE: proposed method includes restoration of defective sections of gas lines by application of insulating protective coats and connection with cathode protection system; defective section of gas line is preliminarily disconnected from gas main and is freed from natural gas; gas released from this section is compressed and is charged in reservoirs under pressure; gas line surface is cleaned from soil and defective coat by forming temperature gradient and stresses between defective coat and gas line; then finish cleaning of outer surface of gas line is performed at simultaneous suction of dust and gas line is heated to temperature of 70 to 175°C, after which layers of adhesive composition and dielectric insulating coat are applied at succession at overlapping joints between steel pipes of gas line and layer of spiral-shaped coat made from metal at potential more negative as compared with potential of gas line being protected; metal coat is applied in form of tape or foil whose ends are brought out at distance of (0.01-1)d, where d is diameter of pipe. Then, insulating plastic coat is applied on metal coat and after erection of gas line, ends of tape or foil are electrically connected at points of joints of steel pipe over entire length of gas line through switching units and parameter measuring units.

EFFECT: enhanced reliability of corrosion protection; considerable reduction of energy expenses; increased service life of metal coat.

3 cl, 10 dwg

FIELD: construction.

SUBSTANCE: method comprises setting the tip in the end section of the pipe lined by a plastic shell. A protector is fit in the tip with interference. The tip clamps the end of the plastic shell by mandrelling. The tip is fit in the pipe with interference. The tip is mandrelled out of the zone of protector.

EFFECT: enhanced reliability.

2 dwg

FIELD: protection of pipe against corrosion.

SUBSTANCE: method comprises applying prime coat on metallic surface at a temperature of no less than 10°C, applying insulating polymeric belt coating on metallic surface, and heating the coating to provide its shrinking.

EFFECT: enhanced corrosion protection.

6 cl, 1 tbl, 3 ex

FIELD: pipeline construction.

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EFFECT: enhanced reliability.

2 cl, 5 dwg

FIELD: construction.

SUBSTANCE: method comprises applying epoxy primary layer and thermo-shrinking adhesion belt provided with a protecting layer on the surfaces to be insulated. The epoxy primary layer is applied on the surface heated up to a temperature of 60-90°C.

EFFECT: enhanced reliability.

4 cl, 1 tbl

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