RU2384788C1 - Insulating connecting point of metal pipes - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention refers to pipe production, particularly to pipe connecting points made with application of composite fibre materials and can be implemented at fabrication of pipe connecting points corresponding to elements of cathode protection from electric-chemical corrosion in oil-gas-product-pipelines. The insulating connecting point of metal pipes consists of metal branches with circular bosses whereon there is formed a coupling out of composite materials; a circular element is arranged between conjugating ends of the branches; the circular element consists of a lug of rectangular profile and side relative to the lug flanges placed in recesses of branch walls. According to the invention the circular element is made out of rigid insulating material resistant to aggressive mediums, for example to polyamide; the lug is located from the side of an insertion; the flanges are placed in recesses made on internal walls of the branches and fixed with cylinder rings secured in bores of the branches; also profiles of recesses and side flanges are made with gaps between them wherein packing and retaining their position rings are installed.

EFFECT: invention upgrades reliability of electric-insulating connection of pipelines.

1 dwg

Description

The invention relates to the field of manufacture of pipes, namely, nodes of their connections, performed using composite fibrous materials, and can be used in the manufacture of nodes of the pipes, which are elements of cathodic protection against electrochemical corrosion in oil and gas pipelines, heating networks, etc.

Known pipe connection node made by the method, the priority of which is protected by RF patent No. 22939150.

A known knot of connection of metal pipes containing metal pipes (ends) with annular thickenings on which an insert is formed of composite materials, and between the adjacent ends of the pipes placed a sealing element made of rubber and consisting of a protrusion of a rectangular profile and side shelves. The protrusion is placed between the nozzles on the inside, and the shelves are placed in samples made on the outer walls of the nozzles.

The sealing element is fastened to the nozzles with an adhesive joint (see RF patent No. 2232337 for a prototype).

The disadvantages of this connection node arise from the conditions of its operation. Under the influence of internal pressure (10 MPa or more), tear-off forces act on the side walls of the protrusion and the lower walls of the shelves, which can lead to the destruction of the adhesive joint. The side walls of the shelves from bursting under pressure are additionally pressed to the ends of the pipes, while improving the sealing of the connection.

However, with temperature changes in pipes with assembled insulating nodes, this preload may not be enough. In addition, which is very important, in the absence of internal pressure, which occurs when cleaning pipelines, tear-off forces from temperature fluctuations can reach critical values, leading to the destruction of adhesive joints. Aging of the rubber leads to a loss of elasticity of the joints, which impairs adhesion, reducing the reliability and durability of the structure.

The technical task of the present invention is to increase the reliability and durability of the electrical insulating node of the pipe connection due to the use of a more rigid wear-resistant insulation material in the sealing element, not subject to the influence of aggressive environments, and a new design of its placement in the connection unit using ring seals.

The technical result is achieved by the fact that in the insulating node of the connection of metal pipes containing metal nozzles with annular thickenings on which the sleeve is made of composite materials, and between adjacent ends of the nozzles there is an annular element consisting of a protrusion of a rectangular profile and side shelves relative to it, placed in samples of the walls of the nozzles, the annular element is made of rigid insulating material, not subject to the influence of aggressive environments, for example polyamide, the protrusion is placed n from the side of the coupling, and the shelves are placed in samples made on the inner walls of the pipes and fixed by cylindrical rings installed in the grooves of the pipes, and the profiles of the samples and side shelves are made in such a way that gaps are formed between them, in which the sealing and holding their position are placed rings.

All the distinguishing features in the claims are essential.

- The use of a sufficiently rigid insulating material, not subject to the influence of aggressive media, for example, from a number of nylons (polyamide), can significantly increase the wear resistance of the sealing element, evenly transfer forces from internal pressure to the o-rings and to all surfaces in contact with it.

- Making samples on the inner walls of the nozzles, placing side shelves in them with gaps relative to the walls of the samples and placing the o-rings in the gaps allows reliable sealing of surfaces in contact with it, both by pre-compressing the seals with retaining rings and by preloading them from the inner pressure.

- The retaining rings ensure a stable position of the o-rings.

The invention is illustrated in the drawing.

The insulating assembly includes: metal pipes 1 with annular thickenings 2, a composite insert 3, an annular element 4, consisting of a protrusion 5 and side shelves 6, sealing rings 7, retaining rings 8, fixing cylindrical rings 9.

The feature of the node is as follows.

Under the action of internal pressure, the wall of the protrusion and the walls of the shelves abut against the walls of the samples and the composite insert, while choosing technological gaps and pressing the sealing rings. At the same time, compressive, tensile and bending loads arising during operation acting on the elements of the assembly are assumed by the composite coupling, which is carried out on the basis of natural working conditions.

The tests carried out with imitation of full-scale operating conditions confirmed the reliability of the operation of the annular element, o-rings and the entire assembly as a whole.

Thus, the use of the invention will improve the reliability, bearing capacity and, accordingly, the service life of the electrically insulating pipe joints.

Claims (1)

An insulating node for connecting metal pipes containing metal nozzles with annular thickenings, on which a sleeve is made of composite materials, and between adjacent ends of the nozzles there is an annular element consisting of a protrusion of a rectangular profile and shelves lateral relative to it, located in the samples of the walls of the nozzles, characterized in that in it the annular element is made of rigid insulating material, not subject to the influence of aggressive environments, for example polyamide, the protrusion is placed on the side of the couplings s, and the shelves are placed in samples made on the inner walls of the nozzles and fixed by cylindrical rings installed in the grooves of the nozzles, and the profiles of the samples and side shelves are made in such a way that gaps are formed between them, in which the rings are sealed and holding their position.