EA022823B1 - Method and assembly for connecting a pipe to a coupling element - Google Patents

Abstract

The invention relates to construction. The technical result is aimed at expanding the scope of methods and means for diffusion welding of a pipe to a coupling element manufactured from a thermoplastic material, in particular, from polyethylene of increased thermal stability, low-pressure polyethylene or polypropylene. Provided is a welding of a coupling element to a thin-walled pipe with a wall thickness within the range of 1.5-3.0 mm in pipes of the most popular size types having an outside diameter of 16 or 20 mm, and also greater thickness walls with accordingly greater outside diameter. A high degree of uniformity and homogeneity of the diffusion welding zone is achieved, practically excluding narrowing of the passage section of the pipeline in said welding area, devices can be used for welding pipeline elements manufactured from polypropylene-based thermoplastic materials. A method for connecting provides mounting a sleeve (5) into the weldable end of the pipe (1) until a bead (6) rests against the end plane of the pipe; a section of the outside surface of the pipe (1) and a section of the inside surface of the coupling element (2) are heated simultaneously using welding attachments, which are fixed on a heater, until the thermoplastic material is melted on the surfaces of of said areas; then the pipe (1) and the coupling element (2) are removed from the welding attachments and the end of the pipe (1) is inserted into the cavity of the coupling element (2) with the melted surfaces being joined; a final curing of the connection takes place until the melted thermoplastics material hardens, forming a diffusion welding zone (8) with the coupling element (2) to the end pipe (1). The assembly comprises the sleeve (5) in the form of a length of thin-walled pipe with the outwardly bent bead (6) on one of the end planes. The length of the sleeve (5) is greater than the length of the welding zone (8).

Description

The invention relates to methods and means used in construction for the construction of water supply, air conditioning and heating systems, including for the construction of a heat-insulated floor, sewage system, various special-purpose pipeline systems, and more particularly, to a method for diffusion welding of pipes, usually thin-walled, with a socket element made of thermoplastic material, as well as to the connection node of the pipe and the coupling element obtained in this way.

State of the art

Under the coupling element, in the sense of the present invention, is meant a section of a pipe fitting or connecting part element that has an inner cylindrical surface, in the interface zone with which the outer surface of the end of the pipe being connected, when these surfaces are coupled with the thermoplastic material being pre-melted onto them, a diffusion welding zone of the pipe and coupling item.

Such a coupling element may have various fittings, including couplings, elbows, tees, as well as valves, taps, valves, filters, regulators for various purposes and the like.

The listed parts and assemblies can be made entirely of thermoplastic material or partially. The connected pipes can also be made of a continuous thermoplastic material, or the pipes can have one or more intermediate layers, in particular, include an intermediate layer of aluminum alloy or of a copolymer of ethyl vinyl alcohol.

Diffusion welding of pipes and a coupling element made of thermoplastic material involves the following operations:

simultaneous heating of the portion of the outer surface of the pipe and the portion of the inner surface of the coupling element using welding nozzles fixed to the heater until the thermoplastic material melts on the surfaces of these sections;

removing the end of the pipe and the coupling element from the welding nozzles and pairing them with each other with said sections with thermoplastic material molten on the surfaces by inserting the end of the pipe inside the cavity of the coupling element;

the final exposure of the connected pipe end and the coupling element to the curing of the molten thermoplastic material with the formation of the diffusion welding zone of the coupling element with the pipe end (EA 014398 V1, IPC V29C 65/18, 2010).

Coupling elements and pipes made of various types of polypropylene can be easily welded using this method, including pipes with intermediate layers of aluminum alloy or of ethylene vinyl alcohol copolymer, other multilayer pipes and coupling elements made on the basis of other thermoplastic polymeric materials that can be welded as described above method.

For continuous pipes, coupling elements are used that have a hole with an internal radial protrusion, which is also melted during welding and the melted end of the welded pipe abuts against it. For multilayer pipes, coupling elements can be used that have a complex protrusion inside the hole that forms an outward annular groove (KI 2380603 C1, IPC P16 13/00, 2010). In this case, heating nozzles are used for welding, allowing to melt the end of the pipe outside, inside and at the end, and the fitting on the inner surface and all surfaces of the specified annular groove, into which the pipe end is then inserted.

The use of coupling elements of this design significantly reduces the flow cross section of the pipeline, so their use is not advisable.

Along with wide polypropylene-based pipes, pipes are used that are completely made of cross-linked polyethylene (PEX), or only the inner layer is made of this material. Cross-linked polyethylene pipes are distinguished by high operational properties (service life, flexibility, strength, heat resistance), however, the connection of such pipes is carried out using mechanical fittings that clamp the end of such a pipe mechanically, since cross-linked polyethylene pipes cannot be welded.

At present, another type of polyethylene of increased heat resistance has been used (the material is designated RE-KT Ro1ue1yu1epe οί Ka18eb Tetregahe gem Chapsa) for pipes, connectors and pipe fittings of hot and cold water supply and heating systems.

Such high-temperature-resistant polyethylene is in fact a classic thermoplastic that can be easily welded. Pipes made from this polyethylene can be distinguished by a small wall thickness. The use of such heat-resistant polyethylene pipes for welding with coupling elements of welding nozzles used for welding pipelines from materials based on polypropylene and widely distributed has a drawback.

During welding, the pipe is deformed in the welding zone (welding belt) and the geometry of the bore is changed. A welding defect arises, leading either to a complete or partial overlap of the pipe bore or to an insufficiently strong welded joint between the pipe and the coupling element. A similar disadvantage is the welding of thin-walled pipes made of low-pressure polyethylene or polypropylene.

A known method of pipe welding that eliminates this problem, in which the ends of two connected pipes are worn on a thin-walled metal sleeve. The end of the pipe and fitting can be put on the sleeve. Then, a female sleeve is formed over the joint, including from a thermoplastic material corresponding to the material of the pipes being joined (OV 794833 A, IPC V29C65 / 00, 1956).

This well-known method cannot be used due to the fact that it does not correspond to the currently used structural features of pipes, especially multilayer, sleeve elements, is not continuous for the use of tools that are widely used for welding pipes and sleeve elements made of thermoplastics based on polypropylene. It should also be noted its complexity and lack of manufacturability.

SUMMARY OF THE INVENTION

The technical result of the invention is to expand the arsenal of methods and means for diffusion welding of a pipe with a coupling element made of thermoplastic material, in particular polyethylene of high heat resistance, low pressure polyethylene or polypropylene. These methods and tools allow welding of the coupling element with a thin-walled pipe having a wall thickness in the range of 1.5-3.0 mm for pipes of the most common sizes with an outer diameter of 16 or 20 mm, as well as a wall of greater thickness with a correspondingly larger outer diameter. At the same time, high continuity and homogeneity of the diffusion welding zone is ensured, narrowing of the pipe bore in the specified welding zone is virtually eliminated, tools used for welding pipe products made of thermoplastics based on polypropylene can be used.

The achievement of the technical result of the invention provides a method for diffusion welding of a pipe with a coupling element made of thermoplastic material, comprising installing a sleeve in the welded end of the pipe, made thin-walled in the form of a pipe segment with a bent outwardly along one of the ends, the height of which does not exceed the thickness of the pipe, and made of a material that retains load-bearing properties at a temperature exceeding the melting temperature of the thermoplastic material of the pipe and coupling element, d o stop shoulder in the end of the pipe end;

simultaneous heating of the portion of the outer surface of the pipe and the portion of the inner surface of the coupling element using welding nozzles fixed to the heater until the thermoplastic material melts on the surfaces of these sections;

the subsequent removal of the end of the pipe and the coupling element from the welding nozzles and their conjugation with each other by the said sections with the thermoplastic material molten on the surfaces by inserting the end of the pipe into the cavity of the coupling element;

the final exposure of the connected end of the pipe and the coupling element to the curing of the molten thermoplastic material with the formation of the zone of diffusion welding of the coupling element with the end of the pipe.

In contrast to the known technology described above, the method in accordance with the invention provides for the installation of a sleeve of the specified design in a predetermined position.

In a preferred embodiment of the invention, the depth of introducing its end into the sleeve element is preliminarily marked on the pipe, and during the operation of inserting the pipe end into the cavity of the sleeve element, the pipe end is inserted to a depth corresponding to the previously made mark.

In the best embodiment of the invention, a sleeve is used having a longer length than the length of the diffusion welding zone of the coupling element with the end of the pipe.

It is possible that an outer circumferential groove is made in the middle part of the side surface of the sleeve, where the o-ring is located.

It is possible that an additional insert made of a thermoplastic material in the form of a ring having a transverse L-shaped section, which is worn on the pipe end with its location inside the corner cavity of the insert, is used.

In accordance with the invention, welding may be carried out with a pipe with an intermediate layer of aluminum alloy or of a copolymer of ethyl vinyl alcohol.

It is possible to weld a pipe and a coupling element, which are made of a material selected from the group including high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene. Accordingly, the pipe, sleeve element and insert, when used, are made of the same thermoplastic material. The thickness of the welded pipe may lie in the range of 1.5-3 mm.

A sleeve may be used that is made of a material selected from the group consisting of steel, aluminum alloy, copper alloy. The sleeve can be made of a polysulfone-based polymer structural material. A sleeve may be used that is made with a thickness ranging from 0.05 to 3 mm.

In accordance with the described method, the connection node diffusion welding of the pipe with the socket

- 2 022823 an element made of thermoplastic material, further includes a sleeve made thin-walled in the form of a pipe segment with a collar bent outward along one of the ends, the height of which does not exceed the thickness of the pipe, and made of a material that retains load-bearing properties at a temperature exceeding the melting temperature thermoplastic material of the pipe and coupling element.

The sleeve is inserted into the end of the pipe until it stops against the end, and the pipe is inserted into the sleeve by this end to form a part of the inner surface of the sleeve element with a part of the outer surface of the pipe of the interface between the diffusion welding of the sleeve element and the pipe end. The length of the sleeve is greater than the length of the specified zone of diffusion welding.

In contrast to the known connection unit, where a sleeve is used to connect parts of a thermoplastic material, the invention is characterized by the design of the connected elements, the location of the welding zone, the design of the sleeve and the features of its installation.

The connection node in particular cases of the invention is characterized according to the method described above by the following design features:

outside, in the middle part of the side surface of the sleeve, an annular groove may be made in which the sealing ring is located;

the assembly can be equipped with an insert of a thermoplastic material in the form of a ring between the pipe end and the lateral surface of the inner radial protrusion of the coupling element, with the surfaces of which the insert is paired with the formation of an additional diffusion welding zone;

the pipe may be made with an intermediate layer of aluminum alloy or of a copolymer of ethyl vinyl alcohol;

the pipe and coupling element can be made of a material selected from the group including high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene;

the pipe, the coupling element and the insert can be made of a material selected from the group including high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene;

pipe thickness may lie in the range of 1.5-3.0 mm.

the sleeve may be made of a material selected from the group comprising steel, aluminum alloy, copper alloy;

the sleeve may be made of a polysulfone-based polymer structural material;

the sleeve can be made in a thickness ranging from 0.05 to 3 mm.

The implementation of the invention

The possibility of carrying out the invention is illustrated by an example of a specific implementation, which is illustrated in graphic materials.

In FIG. 1 shows a longitudinal section through a joint assembly by diffusion welding of a pipe with a coupling member;

in FIG. 2 - a longitudinal section of the sleeve;

in FIG. 3 is a longitudinal section through a diffusion welding joint of a pipe with a coupling element, the sleeve of which has an annular groove on the outside in the middle of the side surface in which the sealing ring is located;

in FIG. 4 is a longitudinal section through the end of the pipe, into which a sleeve is inserted, and an insert of thermoplastic material in the form of a ring is dressed on the pipe end.

The connection site by diffusion welding (Fig. 1) of the pipe 1 with the coupling element 2, which in a particular particular example is part of the coupling 3 with an internal radial protrusion 4 made of thermoplastic material, further includes a sleeve 5 made thin-walled in the form of a pipe section with the pipe bent outward a shoulder 6 (Fig. 1, 2) along one of the ends, the height of which does not exceed the thickness of the pipe 1, and made of a material that retains load-bearing properties at a temperature exceeding the melting temperature of the thermoplastic mat rial of the pipe 1 and the muff member 2.

The sleeve 5 is inserted into the end of the pipe 1 until it stops against the shoulder 6 in the end 7, and the pipe 1 is inserted into the coupling element 2 with this end to form, on the plot 8, a part of the inner surface of the coupling element 2 and a part of the outer surface of the pipe 1 of the diffusion welding zone of the coupling element 2 pipe end 1. The length of the sleeve 5 is greater than the length of the specified zone (8) diffusion welding.

As shown in FIG. 3 when welding a multilayer pipe 9 (the multilayer pipe 9 in FIG. 3 is not reflected), an annular groove 11 is made on the outside in the middle part of the side surface of the sleeve 10, in which the sealing ring 12 is located. For the same purpose, as shown in FIG. 4, i.e. to prevent delamination of the multilayer pipe 13 (the multilayer pipe 13 in Fig. 4 is also not reflected), the node is equipped with an insert 14 of thermoplastic material in the form of a ring between the end of the pipe 13 and the side surface of the inner radial protrusion of the coupling element (in Fig. 1 correspond, respectively, positions 4, 2), with the surfaces of which the insert 14 is associated with the formation of an additional diffusion welding zone (not shown in the drawings), which covers the bead 15

- 3 022823 sleeves 16.

As indicated above, the pipe (9, 13) can be made with an intermediate layer of aluminum alloy or of a copolymer of ethyl vinyl alcohol. Welding of a multilayer pipe of a different design of intermediate layers can be provided. Welding is mainly provided by pipes with a thickness in the range of 1.5-3 mm and a coupling element made of high temperature resistant polyethylene. Welding can be carried out on pipes and couplings made of low pressure polyethylene or polypropylene. When using the insert 14, it is made of the same material as the welded pipe and the coupling element. A pipe and a coupling element of other thermoplastic materials can be welded, including in the case when the connected pipe is not characterized by a small wall thickness.

The sleeve (5, 10, 16) is mainly made of brass, but steel, aluminum alloy, another copper alloy, as well as a refractory polysulfone-based structural material (for example, polyarylene ether sulfone, polyalkylene sulfone, polyethersulfone) can be used for its manufacture. The sleeve (5, 10, 16) may, depending on the material used, have a thickness of 0.05 to 1 mm. A sleeve of greater thickness can be used with an appropriate size of the parts to be welded.

The technology (method) of the connection by diffusion welding of a pipe with a coupling element made of a thermoplastic material, which allows to obtain the connection node described above, involves the following operations:

installation in the welded end of the pipe (1, 9, 13) of a sleeve (5, 10, 16), made as described above, until it stops with a shoulder 6 at the end of the end of the pipe (1,9, 13);

simultaneous heating of the portion of the outer surface of the pipe (1, 9, 13) and the portion of the inner surface of the coupling element (2) using welding nozzles fixed to the heater until the thermoplastic material melts on the surfaces of these sections;

the subsequent removal of the end of the pipe (1, 9, 13) and the coupling element (2) from the welding nozzles and their conjugation with each other by the said sections with thermoplastic material melted on the surfaces by inserting the end of the pipe (1, 9, 13) inside the cavity of the coupling element ( 2);

the final exposure of the connected pipe end (1, 9, 13) and the coupling element (2) until the molten thermoplastic material is solidified to form diffusion welding zone (8) of the coupling element (2) with the pipe end (1, 9, 13).

Before performing these operations, the depth of introducing its end into the sleeve element (2) can be preliminarily marked on the pipe (1,9, 13), and during the operation of inserting the end of the pipe (1,9, 13) inside the cavity of the sleeve element (2) the insertion of the end of the pipe (1, 9, 13) is carried out to a depth corresponding to the indicated previously made mark.

The invention is not limited to the above embodiment. Other specific forms of constructive realization of the invention, which are designed with its use and ordinary engineering knowledge, are also within the scope of patent claims. Can also be supplemented by additional known operations, the technology of joining by diffusion welding of the pipe (1, 9, 13) with the coupling element (2).

Claims (23)

CLAIM 1. The method of connecting by diffusion welding of a pipe with a coupling element made of thermoplastic material, comprising installing a sleeve into the welded end of the pipe, made thin-walled in the form of a pipe segment with an outward-curved flange along one of the ends, the height of which does not exceed the thickness of the pipe, and made of material retaining load-bearing properties at a temperature exceeding the melting temperature of the thermoplastic material of the pipe and the coupling element, until it stops with a shoulder at the end of the pipe end, while heating Surveillance of the outer surface of the pipe and the portion of the inner surface of the coupling element using welding nozzles fixed to the heater until the thermoplastic material melts on the surfaces of these sections, the subsequent removal of the pipe end and the coupling element from the welding nozzles and their interconnection with the said sections with the thermoplastic material molten on the surfaces by inserting the end of the pipe into the cavity of the coupling element, the final exposure of the connected pipe end and the coupling e element before curing the molten thermoplastic material with the formation of the diffusion welding zone of the coupling element with the end of the pipe. 2. The method according to claim 1, characterized in that the depth of the insertion of its end into the coupling element is preliminarily marked on the pipe, and during the operation of inserting the end of the pipe into the cavity of the coupling element, the end of the pipe is inserted to a depth corresponding to the previously made mark. - 4 022823 3. The method according to claim 1, characterized in that they use a sleeve having a greater length than the length of the diffusion welding zone of the coupling element with the end of the pipe. 4. The method according to claim 1, characterized in that they use a sleeve on the outside in the middle part of the side surface of which an annular groove is made, where the o-ring is located. 5. The method according to claim 1, characterized in that it further uses an insert of a thermoplastic material in the form of a ring having a transverse L-shaped section, which is worn on the pipe end with its location inside the corner cavity of the insert. 6. The method according to claim 5, characterized in that they carry out welding with a pipe with an intermediate layer of aluminum alloy or of a copolymer of ethyl vinyl alcohol. 7. The method according to claim 1, characterized in that the pipe and the coupling element are welded, which are made of a material selected from the group including high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene. 8. The method according to claim 5, characterized in that the pipe, coupling element and insert are welded, which are made of a material selected from the group including high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene. 9. The method according to claim 1, characterized in that the pipe is welded, the thickness of which lies in the range of 1.5-3 mm. 10. The method according to any one of claims 1 to 8, characterized in that they use a sleeve that is made of a material selected from the group comprising steel, aluminum alloy, copper alloy. 11. The method according to any one of claims 1 to 8, characterized in that they use a sleeve that is made of a polysulfone-based polymer structural material. 12. The method according to any one of claims 1 to 8, characterized in that the sleeve is used, which is made with a thickness lying in the range from 0.05 to 3 mm. 13. The connection of the pipe and the coupling element made of thermoplastic material, made by diffusion welding, containing a sleeve made thin-walled in the form of a pipe segment with a collar bent outward along one of the ends, the height of which does not exceed the thickness of the pipe, and made of a material that retains bearing properties at a temperature higher than the melting temperature of the thermoplastic material of the pipe and the coupling element, while the sleeve is inserted into the end of the pipe until it stops with the shoulder in the end, and these pipes end is inserted into the muff member to form at the site of conjugation of the inner surface of the muff member with a portion of the outer surface of the diffusion pipe welding muff member zone of the pipe end, wherein the sleeve is longer than the length of said diffusion bonding zone. 14. The connection according to item 13, characterized in that on the outside in the middle part of the side surface of the sleeve is made an annular groove in which the o-ring is located. 15. The connection according to item 13, characterized in that it is equipped with an insert of thermoplastic material in the form of a ring between the end of the pipe and the side surface of the inner radial protrusion of the coupling element, with the surfaces of which the insert is paired with the formation of an additional diffusion welding zone. 16. The compound according to 14, characterized in that the pipe is made with an intermediate layer of aluminum alloy or a copolymer of ethyl vinyl alcohol. 17. The compound according to clause 15, characterized in that the pipe is made with an intermediate layer of aluminum alloy or of a copolymer of ethyl vinyl alcohol. 18. The compound according to any one of paragraphs.13-17, characterized in that the pipe and coupling element are made of a material selected from the group comprising high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene. 19. The compound according to clause 15, characterized in that the pipe, the coupling element and the insert are made of a material selected from the group including high-temperature resistant polyethylene, low-pressure polyethylene, polypropylene. 20. The compound according to any one of paragraphs.13-17, 19, characterized in that the pipe thickness lies in the range of 1.5-3 mm. 21. The compound according to any one of paragraphs.13-17, 19, characterized in that the sleeve is made of a material selected from the group comprising steel, aluminum alloy, copper alloy. 22. The compound according to any one of paragraphs.13-17, 19, characterized in that the sleeve is made of a polysulfone-based polymer structural material. 23. The compound according to any one of paragraphs.13-17, 19, characterized in that the sleeve is made of a thickness lying in the range from 0.05 to 3 mm.