Connection enamelled pipes and the method of its execution

 

The invention relates to the construction and used for the construction of pipelines transporting corrosive environment. The compound contains two tubes enamel, mounted coaxially inside the pipes enameled sleeve with the outer radial ledge. made around the perimeter of the middle section of the sleeve, which has a slit along the length. Before enameling sleeve after it is cut to length to control the elastic deformation of the sleeve on the outer diameter to the size of the inner diameter enamelled pipes perform on a radial protrusion in pairs diametrically cuts. Compress bushing enameled, put on the joint faces of the elements connect the slip fusible silicate enamel. After placing the sleeve on the inside of the ends of adjacent pipes and rasathi the surface of contact between the connected elements are pressed towards each other due to the accumulated compression sleeve of energy. Form a corrosion-resistant coating in the form of an enamel composition on the length of the connection is equal to the length of the sleeve over the entire surface of contact of the ends of the pipe with the sleeve, using the heat of the welding when forming the root of the weld. Given recommended is soedineniya. 2 C. and 7 C.p. f-crystals, 2 Il.

The invention relates to valves, particularly to joints of pipes with internal enamel welding and can be used in the Assembly of pipelines designed to transport corrosive environments in the oil, gas, chemicals, utilities and other industries.

It is known connection of pipelines containing a set of fastening elements: mobile and stationary flanges, a resilient ring and the sleeve, which are mounted on the ends of adjacent pipes and tighten fasteners (1). The connection is structurally and design-hard, massive and does not guarantee reliability, as it does not provide protection against corrosion of the joints of pipes.

A device for protecting an internal welded seam pipe containing a bushing with socket ends, bearing in itself the installation tabs, sealing elements - elastic cuff (2). However, when welding pipes elastic cuffs are heated to high temperatures during operation quickly lose their original properties, which leads to depressurization sealing and proniknout the tattoo is the connection enamelled pipes, consisting of two pipes and installed coaxially inside them in the zone of junction of the sleeve with the inner enamel, with the annular groove and radial thrust tabs. The cavity between the groove of the sleeve and the inner surface of pipes filled with a material with adhesive properties. The compound contains a rubber o ring. After welding of the pipes above the cavity are two holes for injection into the adhesive material such as glue "Ciacil EA" (3). Well-known connection inherent in the above-mentioned disadvantages. In addition, for the formation of a corrosion layer requires additional equipment (heating equipment, transfer pumps, and others), which complicates the implementation of the connection in the field, and use as a protective material glue, rubber seals and the presence of stress concentrators in the connection zone (holes) reduce the reliability of the connection during operation of the pipeline.

Object of the invention is the elimination of existing disadvantages of the known solutions, namely improving the reliability, corrosion resistance of the welded connection, its strength with long-term use is, the reduced energy and material consumption, reducing Assembly time and welding connection.

The problem is solved in that the proposed connection enamelled pipes closest to the known (3) major structural elements and the achieved technical result containing two tubes with internal enamel, enameled sleeve with the outer radial ledge mounted coaxially inside the pipes, anti-corrosion coating between the inner surface of the ends of adjacent pipes and the outer surface of the sleeve, but on the proposed connection sleeve has a slit along its length, and the radial protrusion is made around the perimeter of the middle section of the sleeve, the width (l) and height (h) of the protrusion, and length (L) of the sleeve and the thickness (t) of its walls correspond to the thickness (S) of the walls of adjacent pipes respectively as l/S=(0,1-0,3), h/S=(0,3-0,6), L/S (2-5), t/S=(0,12-0,35), and the sleeve is coupled with the inner outer enamel coating of the same grade composition of enamel and the enamel coating of the pipes, and as the binder component anticorrosion coatings enamel composition used fusible silicate enamel temperature coefficient of linear expansion (TCLE), ravnos perform structural features of the sleeve. The ratio of the radial protrusion of the sleeve length and thickness of its wall is correlated with the thickness of the walls of adjacent pipes and the limits of these ratios is established experimentally, taking into account the education isothermal temperature field in the heat-affected zone created during the formation of the root pass welding of pipes with different wall thickness. Taking into account this factor use cut sleeve, the special composition of the slurry for the formation of low-melting enamel with TCLE equivalent TCLE enamel pipe and sleeve. All marked creates conditions for the formation of durable corrosion-resistant layer on the entire surface of contact between the pipe and sleeve in the form of an enamel composition, including the enamel coating of the pipe and the sleeve, and the process is carried out using thermal energy transmitted from the welding of pipes.

Select values TCLE fusible enamel set with regard to bringing complex operational properties of corrosion-resistant layer to the properties of the enamel coating of the pipe and sleeve.

Radial collar around the perimeter of the sleeve in addition to the functions that provide symmetrical geometrical fixation of the pipes relative to each other and the sleeve, when the arc swarms with the root of the welding seam around the perimeter of the pipe.

Cut along the length of the sleeve, made by one of the following: on a line parallel to the axis, at an angle to the axis of the sleeve or in a broken line, provides compensation for the stresses arising from thermal and mechanical impacts during joint Assembly, including welding. With the same purpose on a radial projection performs at least four transverse incision at its height, made in pairs in diametrically opposite directions.

Given the known methods of joining pipes with an internal corrosion-resistant coating of different materials in this application in connection enameled tubes designed a way for his execution.

Sources of information there is a method of joining pipes by their articulation with the intermediate element (4). In the cavity between the intermediate member, the elastic seal at the ends and the inner surface of the pipe after welding through the fittings are served hot air and fill the cavity with liquid hardening material. Then the cavity is rinsed with hot air before the formation of the solid protective film and fill it not hardening corrosion-resistant material. The disadvantages of the method: complex instrumentation, mnogovershinnoe, reducing the Hildren, forming a cavity, weakening the strength of the connection) associated with the use of rubber seals, type of anticorrosive material, technological holes in the weld joint area.

Known methods of joining metal pipes with an internal corrosion-resistant coating (5), thin lined pipe (6) or bilateral enamelled pipes (7). These methods are used to join pipes using two intermediate elements of corrosion-resistant metal, mechanical compression, dual welding (5, 6) or connection enamelled tubes with press-fitting them heated intermediate element (7).

In addition to the above disadvantages? the means of connection is not applicable for joining pipes of external transport pipelines experiencing the longitudinal and transverse amplitude load. This triggers the discontinuity connections, corrosion processes, especially in the area of the welded connection.

The closest in technical essence and the achieved result claimed is a method of connecting pipes with an inner thermoplastic coating (8), including the inside of the pipe ends on the site without termoplastic the annular groove thermoplastic and heat-insulating material, and grooves and sealing rings. Pipes are connected by welding, in which the ends of the internal coating of the pipe at a distance greater than the width of the ring groove and in contact with the coating of the pipe portion of thermoplastic material of the sleeve weld between themselves by melting due to the heat of welding.

Thus, sealing of welded connections inside the tubes used in this method is carried out on a small circular area of the joint elements, and the internal area of the welded connection is in contact only with insulating material and does not protect it from corrosion in case of discontinuity of the plot of melting during welding or during the process of variable loads on the pipelines during operation. Therefore, the above-mentioned disadvantages characteristic of the known method chosen for the prototype.

The task proposed by the invention, a method of connecting pipes with inner enamel using the proposed in this application connection enamelled pipes is to eliminate the disadvantages of the known solutions: improving the reliability, corrosion resistance of the welded connection, its strength during long-term operation of the pipeline is their energy consumption, material consumption, reduce Assembly time and welding connection.

While the proposed method does not require special equipment, expensive materials and high qualification of the personnel.

The problem is solved in that in the proposed method of connection enamelled pipes, including enameling sleeve (coating), the joint pipe sleeve (sleeve inside the pipe ends), welding, forming in the process of welding corrosion-resistant coating between the ends of the pipe and the sleeve in contrast to the known method using a sleeve with a slit along its length and a radial ledge around the perimeter of the middle section of the sleeve, the width (l) and height (h) of the protrusion and the length (L) of the sleeve and the thickness (t) its walls are interconnected with the thickness (S) of the walls of adjacent pipes ratios: l/S=(0,1-0,3), h/S=(0,3-0,6), L/S=(2-5), t/S=(0,12-0,35), and the sleeve is coupled with the inner outer enamel coating of the same grade composition of enamel and the enamel coating of the pipes, and as the binder component anticorrosion coatings enamel composition used fusible silicate enamel with TCLE close TCLE enamel pipe and sleeve, thus, before enameling sleeve after RA is different pipes, then spend the compression bushing enameled, mainly to the closure of the walls where it is cut, then put on the joint faces of the joint elements (sleeve and the pipe ends) the slurry for the formation of a fusible silicate enamel, and after placement of the sleeve on the inside pipe surface contact elements of the connection are pressed to each other due to the accumulated energy when rasathi sleeve and using the heat of welding and accumulated the metal pipe wall hover the root of the weld, form a corrosion-resistant coating in the form of an enamel composition (enamel pipes, sleeves and fusible silicate enamel) on the length of the connection pipe equal to the length of the bushing, on the entire contact surface of the pipe ends with Bush.

Significant advantages of the constructive characteristics of the sleeve used in connection enamelled pipes will be confirmed in the way of its realization.

Flare cut sleeve to the size of the inner diameter enamelled pipes allows to accumulate mechanical energy when the compression sleeve, which is then used for a tight fit of the surfaces prepared for placement of the sleeve on the inside of the ends of a connected t the center of the sleeve, arising because of the inaccuracy of manufacture, tolerances, deviations elleptical form, as well as changes in the thickness of the enamel coating. When rasathi sleeve inside the pipes is forced filling paste of the slip fusible silicate enamel. Thus, between the enamel from the same brand enamel (on the pipe and sleeve) is formed by a layer of slip, fusible silicate enamel. The choice fusible silicate enamel associated with the use of heat from the welding of pipes at the maximum distance from the root of the weld. During the formation of the weld from the heat accumulated metal pipe slip melted with the formation of the layer silicate enamel. At the same time, the enamel coating of the pipes and sleeve melts without losing the original clutch with metallic surface. During this period, created favorable thermodynamic and kinetic conditions for the formation of strong chemical bonds of the phase components of the basic enamel coatings with fusible silicate enamel.

Upon cooling the same linear thermal expansion coefficient in contact with the welding enamels is the condition for the formation of dense, strong, with good ductility corrosion-resistant coating in the form of em is with the ends of adjacent pipes.

The probability of obtaining a high-quality anti-corrosion layer increases with the placement of the bushings in the pipes cut down, and after placing the sleeve in one of the tubes during the filling of the cavity cut paste slurry fusible silicate enamel.

After welding the weld cavity incision is covered with a layer of enamel compositions formed by the cooling of the metal compounds.

In Fig.1 and 2 shows in longitudinal section a General view of the connection enamelled pipes in working condition before pointing the root of the weld.

Connection (Fig.1) consists of two pipes 1, 2 with the inner enamel 3, sleeve 4 with the inner and outer enamel coating 5 of the same grade composition, and that the enamel coating of the pipe on the perimeter in the middle section of the sleeve has a radial protrusion 6, and the length of the wall through the incision 7, made by one of the following: at an angle or parallel to the axis of the sleeve by a broken line. The pipes are connected to the root of the welding seam 8, the length of the connection pipe equal to the length of the bushing has a corrosion-resistant coating 9 of the enamel composition, including enamel coatings, pipes, sleeves and fusible silicate enamel.

In Fig.2, also denoted: 10 - slip silicate radial protrusion of the sleeve, h - the height of the radial protrusion of the sleeve b is the width of the slit sleeve.

The dimensions of the sleeve interconnected with the wall thickness of the pipe: l/S=(0,1-0,3), h/S=(0,3-0,6), L/S=(2-5), t/S=(0,12-0,35), b/S=(0,04-0,1).

Under specific inner diameter and wall thickness enamelled pipes 1 and 2, subject to connection, make the sleeve 4, the external diameter of which is determined taking into account the standards and requirements of free landing of connected elements. Other dimensions of structural elements of the sleeve, the wall thickness (t) length (L), width (l) and height (h) of the radial protrusion 6 and the width of cut (b) are performed according to established ratios depending on the wall thickness of the pipe. Made sleeve is cut along the length (L) width (b), equal (0,04-0,1)s.

For regulating the elastic-plastic deformation occurring during the preparation of the sleeve for connection to the pipe, the radial protrusion 6 perform at least four transverse incision height pairs in diametrically opposite directions.

Cut sleeve resultshowever on the outer diameter to the size of the inner diameter enamelled pipes, then emulerat over the entire surface of the brand enamel used for the enamelling of pipes. Enameled sleeve to compress Caprice fluidity and TCLE, close TCLE enamels coatings pipe and sleeve. The slip 10 (in the form of paste or doughy mass) by the conventional technology enameling metal products applied on the external surface of the sleeve 4 and the inner surface of the ends of adjacent pipes at a distance of half the length of the sleeve. The sleeve is placed first in one of the pipes until it touches the pipe end and the radial protrusion 6 of the sleeve 4 section 7 down. Due to the fact that when the compression bushing enameled upon contact of the walls of the cut are saved cavity, they additionally are filled with a paste of the slip. After placing the sleeve in the second pipe it open. The wall of the sleeve due to the elastic deformation constant force is pressed against the walls of the pipe and the slip, filling all voids shall be distributed in the form of a continuous layer 10 between the walls of the pipe and sleeve. The connection is to be prepared for welding the joint between the pipes 1 and 2 (Fig.2).

When forming the root of the weld, except the ends of the pipe wall, melting the metal top of the lip of the bushing. From thermal energy emitted during welding and transmitted through the protrusion and the wall of the pipe, is warming up and softening of the enamel coating of the pipe and sleeve, and slip melting fusible emka enamel and pressure of the arc is thermodynamic interaction between contacting molten enamel. Thanks to the close values of thermal expansion enamels, during cooling of the welded connection is formed solid, dense with sufficient ductility corrosion-resistant coating of the enamel composition 9 throughout the length and surface of contact between the sleeve and welded pipes. Sleeve (through radial protrusion) and the pipes are connected to the root of the welding seam, which reinforces the strength of the connection as a whole.

For said pipe connection and method of its execution does not require additional equipment and energy consumption (only used heat welding process with the isotherm thermal fields generated in the heat-affected zone on the metal from the heat of welding), special training and qualifications of performers, which is very important to make the connection in the field.

The example run. To connect enamelled pipes with an inner diameter of 245 mm and a wall thickness of 20 mm sleeve made from a grade of steel used for the tubes. Bushing parameters: outer diameter taking into account the tolerances on the free landing and the thickness of the enamel coating is 241 mm, wall thickness 2.5 mm, length 56 mm, width and height of the protrusion of 2.8 and 9.0 mm, respectively. On diametrically protivotoka cut to length at an angle of 15to its axis at a width of 2 mm and flared at the outer diameter to the size of the inner diameter of the enameled tube. On the surface of the expanded sleeve by known techniques applied enamel coating enamel brand ASBT-9 TCLE 10510-7, 1/C used in the enamelling pipes.

Enameled sleeve has been compressed to the closing of the cut walls and fixed in a compressed state.

Based on the results of the study of the distribution at welding temperature field on metal depending on the wall thickness of the welded connection is selected in the special composition of the slip with a minimum melting temperature for the formation of low-melting enamel with TCLE 0510-7, 1/C i.e., equivalent TCLE enamel pipe and sleeve, an entire section of the welded joint on the length of the sleeve. Close values of thermal expansion of enamel is an important condition for the formation of high quality coatings with high performance enamel composition, the limiting rate of which is resistance against tensile loads.

After applying the slurry on the surface of the elements of the connection sleeve was placed in tubes and unclenched.

Welding of pipes proizv.

Weld has stood the test according to the existing methods on the strength of the welded joint, the density and tightness of the enamel composition and the high corrosion resistance of the welded connection in various media, transported through pipelines.

Currently, the proposed connection enamelled pipes used in connection 400 m of pipelines in JSC "Neftegazstroy" , Volgograd.

The sources used information

1. RF patent № 2158872.

2. Certificate of utility model No. 20360.

3. RF patent № 2080510.

4. RF patent № 2080509.

5. RF patent № 2202457.

6. RF patent № 2153120.

7. RF patent № 2158871.

8. RF patent № 2157479.

Claims

1. Connection enamelled pipes containing two tubes enamel, mounted coaxially inside the pipes enameled sleeve with the outer radial ledge and placed between the inner surface of the ends of adjacent pipes and the outer surface of sleeve anti-corrosion coating, characterized in that the radial protrusion is made around the perimeter of the middle section of the sleeve, the latter has a slit along its length, the inner and outer enamel coating has Maro is th fusible enamel temperature coefficient of linear expansion (TCLE), close TCLE enamel pipe and sleeve, and the width (l) and height (h) of the radial protrusion and the length (L) of the sleeve and the thickness (t) of its walls belong to the thickness (S) of the walls of adjacent pipes respectively as l/S=(0,1-0,3), h/S=(0,3-0,6), L/S=(2-5), t/S=(0,12-0,35).

2. Connection on p. 1, characterized in that the width of the slit sleeve is (0,04-0,l)s.

3. Connection under item 1 or 2, characterized in that the cut of the sleeve along its length is made on a line parallel to the axis of the sleeve.

4. Connection under item 1 or 2, characterized in that the cut of the sleeve along its length is made at an angle to the axis of the sleeve.

5. Connection under item 1 or 2, characterized in that the cut of the sleeve along its length made by a broken line.

6. The compound according to any one of paragraphs.1-5, characterized in that the radial protrusion of the sleeve has at least four pairs of diametrically transverse incision at its height.

7. The method of connecting pipes with internal enamel coating, including enameling sleeve, placing the sleeve on the inside of the ends of pipes, welding, forming in the process of welding corrosion-resistant coating between the ends of the pipe and the sleeve, characterized in that use sleeve with a slit along its length and a radial ledge around the perimeter of the middle section of the sleeve, with the inner and washago coverage use fusible silicate enamel temperature coefficient of linear expansion (TCLE), close TCLE enamel pipe and sleeve, and before enameling sleeve after it is cut to length to control the elastic deformation of the sleeve on the outer diameter to the size of the inner diameter enamelled pipes perform on a radial protrusion in pairs diametrically cuts, hold the compression bushing enameled, put on the joint faces of the elements connect the slip fusible silicate enamel, and after placement of the sleeve on the inside of the pipe ends when rasathi sleeve to the contact surfaces of the joint elements are pressed towards each other due to the accumulated energy, and then form a corrosion-resistant coating in the form of an enamel composition on the length of the connection, equal to the length of the sleeve over the entire surface of contact of the ends of the pipe with the sleeve, using the heat of the welding when forming the root of the weld, the width (l) and height (h) of the radial protrusion and the length (L) of the sleeve and the thickness (t) of its walls belong to the thickness (S) of the walls of adjacent pipes respectively as l/S=(0,1-0,3), h/S=(0,3-0,6), L/S=(2-5), t/S=(0,12-0,35).

8. The method of connecting pipes under item 7, characterized in that the compression bushing enameled done before closing the walls in places it cut.

9. The method of pipe connection is

 

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