RU2471110C1 - Permanent pipe connection assembly, and method for its formation - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: permanent pipe connection assembly is formed of a bushing. Wall thickness of bushing is comparable to wall thickness of attached pipes. A groove (bore) is made in the bushing centre to install a fastener in the form of a stop ring. That fastener serves as a shaper of uniform weld. Prior to installation of bushing on internal surface of connected pipes, layer of plastisol paste is applied. For tight filling of plastisol paste to the gap between bushing and pipe on pipe ends there located are sealing gaskets. Bushing is introduced to the first connected pipe up to the stop; then, connected pipe is led onto it. Besides, plastisol paste fills in the gap between bushing and pipes, which is restricted with sealing gaskets, thus providing the butt joint tightness. Pipe connection is performed by welding. At that, the proposed bushing is turned out to be placed inside the connection, and fastener is welded along the perimetre to the connected pipes when the weld is being performed. Protective coating is applied to internal and end surfaces of bushing.

EFFECT: invention improves reliability of connection of permanent welded connection.

2 cl, 3 dwg

Description

The group of inventions relates to the construction of pipeline transport and is used when laying pipelines formed from pipes made of materials joined by welding.

The invention is known, "Welding joint of the pipeline" (patent RU No. 2283739, V23K 31/02, F16L 13/02, publ. Bull. No. 26 dated 09/20/2006). This assembly contains output connected parts of metal pipes with a protective coating applied to their inner surface and a sleeve located inside these pipe parts. The joints of the mentioned pipe parts on the sleeve are connected by manual and / or automatic welding to obtain a weld, the area of which exceeds the normal cross-sectional area of these pipe parts. The connection has annular elements, annular unreinforced and / or reinforced rubber seals, heat-insulating material, sealing material, L-shaped ring emphasis or at least three L-shaped emphasis equally spaced in the radial plane and used to set the centers of mass. A sleeve located inside said outlet or connected pipe parts is made with a cylindrical section and conical sections flared and / or machined with a blade tool and connected with it. It is placed inside these parts of the pipes in such a way that the edges of the pipes are in contact with the L-shaped ring stop or the L-shaped stops. The protective coating on the inner surface of the pipes is applied at a distance from their ends with the formation of a thermally unloaded zone in the application zone. A L-shaped ring stop or L-shaped stops are placed on half the length of the sleeve and are rigidly fixed on its outer surface, and a protective coating is applied on the inner surface of the cylindrical section and the conical sections of the sleeve mating with it. The ring elements are rigidly fixed on the outer surface of the cylindrical section of the sleeve, equally offset from its ends and installed opposite each other. Ring non-reinforced and / or reinforced rubber seals are placed on the outer surface of the sleeve between the protective coating applied to the inner surface of the pipes, the ends of the ring elements and the conical sections of the sleeve and are in close contact with them. The heat-insulating material is rigidly fixed to the outer surface of the cylindrical section of the sleeve between the ends of the ring elements, and the sealing material is applied to the outer surface of the conical sections of the sleeve.

The disadvantages of this device are:

- the complexity of the design and high complexity associated with a large number of difficult to manufacture and precisely customized parts, including L-shaped ring stops;

- low reliability associated with the thickness of the self-hardening sealant, since the thicker the layer of self-hardening sealant, the higher the likelihood of its destruction over time due to the difference in temperature expansion coefficients of pipe materials and sealant;

- low quality of the resulting weld, which is due to uneven heat distribution due to the use of the L-shaped ring stop, unable to fulfill the function of a shaper of a uniform weld.

The closest in technical essence and the achieved technical result is the invention "Welded joint system" (patent RU No. 2230970, F16L 13/00, publ. Bull. No. 17 dated 06/20/2004). It is an integral pipe connection unit and contains two pipes and a sleeve placed in them, having an outer central annular groove with a heat-resistant composition and clamps in the middle of the length, while the sleeve is made of fiberglass and symmetrically made from the central ring of the groove in pairs grooves for elastic seals , for example cuffs, and cuffs closest to the central groove are mounted with the possibility of longitudinal movement and interact with an elastic element, for example, metal springs There is a memory with memory installed on top of the heat-resistant composition along the perimeter of the sleeve between the clamps, and a self-hardening sealant is placed between the seals.

This technical solution is selected as a prototype, as it contains the largest number of essential features that match the essential features of the claimed node integral connection. However, the prototype has significant disadvantages, namely:

- the complexity of the design and high complexity associated with a large number of difficult to manufacture and precisely customized parts, including springs made from expensive and difficult to process metal with memory;

- a significant narrowing of the bore at the junction and, as a result, increased resistance to fluid flow, due to the need to place the spring and the fact that the insulator from the thermal effect of the pipes being welded on the sleeve is only an air gap, which should be of sufficient thickness for this;

- low reliability associated with the thickness of the self-hardening sealant, since the thicker the layer of self-hardening sealant, the higher the likelihood of its destruction over time due to the difference in temperature expansion coefficients of the pipe materials, the sleeve and the sealant, while additional elements for isolating the joint from the aggressive medium are not provided .

From the description of the invention “Welded joint system” (patent RU No. 2230970, F16L 13/00, publ. Bull. No. 17 from 06/20/2004) there is a known method for the formation of the previously described site one-piece pipe connection. This method includes the implementation of a fiberglass cylindrical sleeve with a central groove located in the middle of the length and with a heat-resistant composition placed in it, as well as with clamps fixed uniformly in the center by means of an epoxy compound and evenly located in the center of the circle. Two grooves are made on each side of the central groove, into which elastic seals are placed, for example cuffs. In this case, the cuffs closest to the central groove are axially movable and interact with an elastic element, for example, a metal spring with a memory pre-installed around the sleeve perimeter on top of the heat-resistant composition between the latches. A self-hardening sealant is placed between the cuffs, the outer diameter of the elastic seals being equal to the sum of the inner diameter of the connected pipes and the tolerance for this diameter, and the outer diameter of the sleeve equal to the smallest inner diameter of the pipes being welded. Then form the site of one-piece pipe connection. This happens as follows. A sleeve is installed in the pipe with seals and self-hardening sealant applied to the stop of the clamps at the pipe edge. Then, on the other end of the sleeve with seals and self-hardening sealant, they put the second pipe all the way into the retainer and weld the joint with a seam, while the retainer is fused with a seam and the sleeve is stationary relative to the seam, while the spring takes the specified value from the thermal energy received when welding the pipes position, changing its height from H1 to H2, acting on the internal seal, which acts on the self-hardening sealant, forcing it to fill all possible voids.

This known method is taken as a prototype, as it contains the largest number of essential features that match the essential features of the proposed method. However, the prototype has significant disadvantages, namely:

- technological complexity in the formation of a permanent connection node due to the use of a large number of component parts, including a spring made of hard-to-work and scarce metal with memory;

- low reliability of the formed site of one-piece pipe connection, since the clamps are in the form of separate parts, and they do not cover the entire weld, which does not allow to form a uniform weld;

- the difficulty of securing the sleeve using clamps. The first task is to create a new unit of one-piece pipe connection, which allows to achieve the following technical result: to increase the reliability of pipe connections while simplifying the design.

The second task is to create a new way of forming an integral pipe connection node, which allows to achieve the following technical result: to increase the reliability of the permanent pipe connection assembly being formed while simplifying the technology of its formation.

The first problem is solved as follows. In a known fixed pipe joint assembly comprising two pipes and a sleeve placed therein made of fiberglass and having a central annular groove with a clamp on the outer surface in the middle of the length and symmetrically located from the center at the ends of the sleeve of the groove with elastic seals, ACCORDING to the present invention, the clamp is made in in the form of a detachable metal ring with an outer diameter depending on the internal diameters of the pipes to be welded, and with the possibility of performing the function of the former evenly about the weld between the ends of the pipes to be joined, conical grooves are made at the ends of the sleeve along the inner and outer diameters, a layer of a protective coating of epoxy-based material is applied to the inner and end surfaces of the sleeve, and for sealing the joint between the pipe and the sleeve there is a space between the elastic seals and the ends bushings over the entire outer diameter of the bushings are filled with sealant.

Such a new technical solution with all its essential features allows us to achieve the following technical result, namely: to increase the reliability of the pipe connection while simplifying the design of the integral pipe connection.

This is due to the fact that the latch as a stop for the connected ends of the pipes is made in the form of a detachable metal ring placed in the annular groove of the detachable ring. It prevents the flow of molten metal from the weld zone into the pipe under the action of gravity. Accordingly, a uniform seam is formed, i.e. the lock in our case serves as a shaper of a uniform seam. In addition, due to the use of a clamp during welding, two sealed parts are formed, each of which serves as a damper to eliminate sound vibrations during operation of this joint and a compensator for the resulting deformations due to the influence of external influences.

Practice has shown that for an average pipe size, when the latch is made in the form of a detachable metal ring, its fit on the sleeve when the pipes are welded reduces heat transfer to the walls of the sleeve. In this case, burnout of the surface layer of the sleeve usually occurs to a depth of 0.1-0.2 mm and practically does not affect the strength parameters of the sleeve. In addition, the low thermal conductivity of the material of the sleeve (0.4 W / (m × K)) prevents the spread of heat through the sleeve, heating the layer of protective coating and sealant. This reduces its viscosity and, accordingly, prevents the leakage of sealant from the bonding zone. Moreover, the ends of the sleeve along its entire outer diameter are filled with sealant. It should be noted that when creating this assembly, the central annular groove usually has a depth of 0.8-1.0 mm in practice, the outer diameter of the ring is 2 mm larger than the inner diameter of the pipes being connected, and plastisol mastic applied with a thickness of 2 is used as sealant -3 mm, and elastic seals are made, for example, in the form of rubber rings.

Compared with the prototype, the proposed unit of one-piece pipe connection has significant differences, and the patent search conducted by the Applicant on this topic did not reveal the popularity of the proposed combination of essential features. Therefore, the claimed invention "Node one-piece pipe connection" can be considered new.

The proposed node integral pipe connection for a specialist explicitly logically does not follow from the prior art. However, certain essential features are known in another set of essential features in devices that are close to their intended purpose. For example, the “Welding joint of the pipeline” is known (patent RU No. 2283739, B23K 31/02, F16L 13/02, publ. Bull. No. 26 of 09/20/2006), which is an integral pipe joint assembly. This assembly contains metal pipes with a protective coating applied to their inner surface and a sleeve located inside the pipes, and the pipe joints on the sleeve are connected by manual and / or automatic welding to obtain a weld whose area exceeds the normal sectional area of the pipes. The connection has annular elements, annular unreinforced and / or reinforced rubber seals, heat-insulating material, sealing material, L-shaped ring emphasis or at least three L-shaped emphasis equally spaced in the radial plane, used to establish centers of mass. The sleeve located inside the pipes is made with a cylindrical section and conical sections flared and / or machined with a blade tool mating with it. It is placed inside the pipes in such a way that the edges of the pipes are in contact with the L-shaped ring stop or the L-shaped stops. The protective coating on the inner surface of the pipes is applied at a distance from their ends with the formation of a thermally unloaded zone in the application zone. L-shaped ring emphasis or L-shaped emphasis placed on half the length of the sleeve and rigidly fixed on its outer surface. On the inner surface of the cylindrical section and the conical sections of the sleeve mating with it, a protective coating is applied. The ring elements are rigidly fixed on the outer surface of the cylindrical section of the sleeve, equally offset from its ends and installed opposite each other. Ring non-reinforced and / or reinforced rubber seals are placed on the outer surface of the sleeve between the protective coating applied to the inner surface of the pipes, the ends of the ring elements and the conical sections of the sleeve and are in close contact with them. The heat-insulating material is rigidly fixed to the outer surface of the cylindrical section of the sleeve between the ends of the ring elements, the sealing material is applied to the outer surface of the said conical sections of the sleeve.

The following essential features are known from this well-known permanent connection assembly:

- a sleeve placed inside the pipes;

- pipe joints on the sleeve are connected by manual and / or automatic welding to obtain a weld;

- the connection has annular elements and annular unreinforced and / or reinforced rubber seals, heat-insulating material, sealing material;

- L-shaped ring emphasis or at least three L-shaped emphasis equally spaced in the radial plane, used to set the centers of mass.

The disadvantages of this combination of essential features are:

- the complexity of the design and the high cost associated with a large number of complex time-consuming to manufacture and precisely customized parts, including L-shaped ring stops;

- low reliability associated with the thickness of the self-hardening sealant, since the thicker the layer of self-hardening sealant, the higher the likelihood of its destruction over time due to the difference in temperature expansion coefficients of pipe materials and sealant;

- low quality of the resulting seam, which is formed unevenly due to the use of the L-shaped ring stop.

In our case, the situation is different.

On the sleeve made of fiberglass, there is a latch, which is made in the form of a detachable metal ring. It prevents the flow of molten metal from the weld zone into the pipe under the action of gravity. Accordingly, a uniform seam is formed, i.e. the lock in our case serves as a shaper of a uniform seam. The ring stop performs the same function, and the loose fit of the ring reduces heat transfer to the sleeve wall.

At the same time, the quality of the welded pipe joint assembly is improved, and the design of this assembly is simplified.

Thus, the inventive node integral connection has an inventive step.

To solve the second problem, it is proposed in a method for creating an integral pipe connection assembly, including preparing the inner surface of the pipe ends, installing a sleeve made of fiberglass inside the connected pipes and having a central ring groove with a clamp on the outer surface in the middle of the length and located grooves symmetrically from the center at the ends of the sleeve with elastic seals, and the implementation of the weld at the junction of the joined pipes, it is proposed:

- to prepare the inner surface of the ends of the pipes by applying a sealant to the edges of the connected pipes so that it fills the space between the elastic seals and the ends of the sleeve;

- Install the sleeve until it stops in the edge of the pipe;

- moreover, the latch is made in the form of a detachable metal ring located in the annular groove, the outer diameter of which is determined by the internal diameter of the pipes being welded, when making a weld, the ring around the entire perimeter is welded to the pipes being connected.

Compared with the prototype, the proposed method for creating an integral pipe connection unit has significant differences, and the patent search conducted by the Applicant on this topic did not reveal the popularity of the proposed combination of essential features. Therefore, the claimed invention, "a Method of creating a site of one-piece pipe connection" can be considered new.

The proposed method for creating a permanent pipe connection unit for a specialist explicitly logically does not follow from the prior art. This is due to the fact that a sleeve made of fiberglass is used, on which a clamp is installed in the form of a detachable metal ring, which serves as a shaper of a uniform weld between the joined ends of the metal pipes. In the known methods for creating an integral pipe connection unit, ring elements are used as a clamp, which are not able to form a uniform weld between the pipe ends being joined (see patent for the invention RU No. 2283739, V23K 31/02, F16L 13/02, publ. Bull. No. 26 dated 09/20/2006).

Practical performance and technical essence is illustrated by the following description and drawings.

Figure 1 is a front view in section of a permanent connection node.

Figure 2 is a sectional view of the edge of the sleeve.

Figure 3 is a view in section of a weld seam node integral connection.

1 - pipe;

2 - sleeve;

3 - clamp;

4 - plastisol mastic;

5 - sealing gasket;

6 - clearance;

7 - a protective coating.

The inventive node permanent connection of pipes and the method of its creation are described together, since they are united by a single inventive concept.

The site (Fig.1, 3) one-piece pipe connection 1 is formed from a sleeve 2, which is made of a composite material based on polyester resins and fiberglass threads. The wall thickness (conventionally shown in the drawing) of the sleeve 2 is comparable to the wall thickness (conventionally shown in the drawing) of the connected pipes 1. The strength parameters of the material of the sleeve 2 are not worse than the parameters of the steel from which the connected pipes 1 are made (for example, steel 20). When using steels with other strength characteristics, wall thickness (conventionally shown) of sleeve 2 is recalculated based on the strength parameters of pipe materials 1 and sleeve 2. A groove (groove) is made in the center of sleeve 2 (conventionally shown in the drawing), for example, by depth 0.8-1.0 mm for mounting the retainer 3, made in the form of a thrust ring, in particular, with a thickness of 1-2 mm (this parameter is determined by the wall thickness of the pipes 1 to be welded and, accordingly, the requirements of GOST for the profile view of butt welded joints ). The outer diameter of the clamp 3 is, for example, 2 mm larger than the inner diameter of the connected pipes 1. This clamp 3 serves as a shaper of a uniform weld (conventionally shown in the drawing) (Figure 3).

Before installing the sleeve 2 on the inner surface (conditionally shown in the drawing) of the connected pipes 1, departing from the ends (conventionally shown in the drawing) of the pipes 1 by about 30 mm, a layer of plastisol mastic 4 is usually applied with a thickness of 2-3 mm (Figs. 1, 2 )

To tightly fill mastic 4 of the gap 6 between the sleeve 2 and the pipe 1 at the ends (conventionally shown in the drawing), the pipes 1 have sealing gaskets 5, for example, in the form of rubber rings. In addition, their presence contributes to the mutual alignment of the connected pipes 1.

The sleeve 2 is inserted into the first connected pipe 1 (welded to the previous ones in the assembled pipeline) until it stops in the retainer 3, then the mating pipe 1 is inserted onto it. In this case, the plastisol mastic 4 fills the gap 6 between the sleeve 2 and the pipes 1, limited by gaskets 5, providing joint sealing (shown on the drawing conditionally).

The pipe connection 1 is performed by welding. In this case, the proposed sleeve 2 is placed inside the connection, and the retainer 3 around the entire perimeter is welded to the pipes 1 to be joined when making a weld (conventionally shown in the drawing). This creates additional rigidity in the weakened section of the sleeve 2, along the groove (conventionally shown in the drawing), and improves the characteristics of the node with respect to the longitudinal shear load. The gap 6 between the sleeve 2 and the pipe 1 is usually 1.5-2.5 mm (depending on the diameter of the pipes and, accordingly, the permissible ellipticity). The presence of this air gap 6 allows the operation of the node to compensate for vibration effects on it and to provide increased reliability of this node.

On the inner and outer diameters of the sleeve 2, conical grooves are performed, which provide a decrease in the node's resistance to the flow of flowing fluid and, accordingly, an increase in the speed of pumped volumes.

The proposed design of the sleeve 2 can significantly facilitate the connection due to its mass, four times less than that used metal bushings.

The used plastisol mastic 4 is created on the basis of polyester resins related to the bushings used in the production of the materials.

On the inner and end surfaces (up to the grooves under the sealing cuffs) of the sleeve 2, a protective coating 7 is applied that is resistant to abrasion (this is necessary if there are abrasive impurities in the flowing fluid: sand, particles of solid rocks). The material of the protective coating 7 has an epoxy base, therefore, provides high adhesion to the material of the sleeve 2 and plastisol mastic 4. The additional coating 7 reduces the roughness of the inner surface of the sleeve 2 and reduces the resistance to fluid flow.

In addition, when machining the ends of the sleeve 2 at working angles, the parallel layers of the glass fiber framework are opened and roughness along the processing contour is created, which, with the above affinity of the materials, provides additional adhesion of the plastisol mastic 4 to the sleeve 2 due to the developed surface.

The material of the sleeve 2 has high dielectric characteristics and is not subject to destruction by stray currents.

The densities of the materials of the sleeve 2 and pipe 1 differ significantly (up to 4 times), which prevents the creation of favorable conditions for the development of various types of vibrations in the pipeline, leading to additional loads directly on the pipe thread 1, but even stronger on the supports (not shown in the drawing )

Thus, when using the proposed one-piece connection, the reliability of the welded joint, as well as the entire structure of the pipeline, increases, the cost and weight of the structure also decreases. At the same time, it is possible to increase the speed of pumping fluid.

Claims (2)

1. An integral pipe connection unit comprising two pipes and a sleeve placed therein made of fiberglass and having a central annular groove with a clamp on the outer surface in the middle of the length and symmetrical grooves located at the ends of the sleeve with elastic seals, characterized in that the clamp is made in the form of a detachable metal ring with an outer diameter depending on the internal diameters of the welded pipes and with the possibility of performing the function of a shaper of a uniform weld between t ends of the pipes, conical grooves are made at the ends of the sleeve along the inner and outer diameters, a layer of a protective coating of epoxy-based material is applied to the inner and end surfaces of the sleeve, and to seal the joint between the pipe and the sleeve, the space between the elastic seals and the ends of the sleeve around the entire outer the diameter of the sleeve is filled with sealant. 2. A method of creating an integral pipe connection assembly, including preparing the inner surface of the pipe ends, installing a sleeve made of fiberglass inside the pipes to be connected and having a central annular groove with a clamp on the outer surface in the middle of the length and grooves with elastic seals located symmetrically from the center at the ends of the sleeve, and the implementation of the weld at the junction of the joined pipes, characterized in that the preparation of the inner surface of the ends of the pipes is carried out by applying a sealant to paradise of the connected pipes so that it fills the space between the elastic seals and the ends of the sleeve, the installation of the sleeve is carried out to the stop of the latch on the edge of the pipe, the latch being preformed in the form of a metal split ring, and then placed in the annular groove of the sleeve, the outer diameter of the metal split ring is determined by the inner diameter of the pipes being welded, and when performing the weld, a metal split ring around the entire perimeter is welded to the pipes being connected with the formation of uniform th weld.

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