SU1679124A1 - Method of pipe coupling - Google Patents

Abstract

The invention relates to the construction of pipelines and can be used in the oil producing, petrochemical, and other industries. The purpose of the invention is to increase the reliability and durability of the joint, which at high pressures allows mechanization of the assembly process. The connection for implementing the method consists of a socket and a pipe. A trumpet has a greater radial stiffness than a pipe. A seal is placed in the lead-in part of the pipe, and the rest of it is used to create friction forces ensuring axial fixation. An axial force equal to Rosev is applied to the pipe.

Description

The invention relates to mechanical engineering, concerns pipe-making equipment and can be used to connect cast-iron and polyethylene pipes with internal anti-corrosion coatings, welding of which is impossible.

The purpose of the invention is to increase reliability and durability by converting the internal pressure of the medium due to friction on conic surfaces,

The drawing shows a bell-shaped pipe connection, a longitudinal section.

The pipe connection consists of an outer pipe 1 with a coupling (socket), an inner pipe 2, a sealing element 3. The pipe (coupling) is made with high radial rigidity, and the inner tube 2 has small radial rigidity

During assembly, the preliminary axial fixation of the pipes is provided by frictional forces due to the mating on the conical surfaces with the tension provided by controlled axial compression with the force

Rose (0,6-0,8) Stg F.

When creating this axial force P0c, the latter causes the maximum permissible deformation in the body of the pipe inserted into the socket (inner pipe). In the socket part (outer tube), due to its small thickness, these stresses are insignificant and depend on the thickness ratio.

After applying pressure to the medium, its effect on the material object is that there is a redistribution

nor r:

deforming in radio

the prestressed state in the pipe body under the socket and in the socket and the occurrence of additional axial frictional force. Since the permissible pressure of the medium is determined by the permissible stresses, the stresses from the preliminary compression in the inner tube under the socket and from the pressure are balanced because they are opposite in sign and equal.

At the socket part, these stresses are summed. Therefore, there is a need to increase the thickness of the socket.

The magnitude of the preliminary deformation of the compression of the inner tube is equal to - DIN (dotted line). A final axial fixation is provided when the working pressure is supplied.

D

In the opposite direction, the inner section of the pipe together with the socket (coupling) up to the value of AR is. With such equality of deformations due to the greater stiffness of the coupling, the internal pressure is perceived with the latter completely at the interface and causes the appearance of additional axial frictional force opposing the opening of the connection. In case of equal deformations of the socket part (coupling) of the CNH - CNT, the force due to pressure is completely transformed into an additional friction force arising at the contact of the conical surfaces. If the equality is violated (YNL-5), when pressure is applied, the frictional force will in any case decrease. The ratio of the hardnesses of the outer and inner cones due to the ratio of average thicknesses hcpi / hcp2 ranging from 1.5 to 5 was found to be calculated

from the condition of equal strength ™ of the outer and inner pipe during joint deformation and at the same time creating the necessary frictional force.

After assembly, a geometrical joint is formed in which the filled annular groove in the initial part of the feed cone with a small rigidity acts as a seal. When using sealants, the injection of polymerizable compositions is carried out through the opening C. The length and rigidity of the sealing section A with low rigidity is selected depending on the magnitude of the working pressure, ensuring the non-opening of the joint and its tightness. The length and rigidity of section B is determined from the conditions of the strength of the pipes and the necessary friction force, ensuring the non-opening of the joint, h

Claims (1)

Claims The method of joining pipes involves inserting the conical surface of the inner pipe into the outer socket with tension and installing an adhesive sealing element into the annular cavity in the contact zone characterized in that. that, in order to increase reliability and durability by converting the internal pressure of the medium due to friction on conical surfaces, an axial compressive force equal to (0.06-0.8) is applied to the pipes. Or F, where OV is the yield strength of the pipe material, FT is the cross-sectional area of the pipe, causing elastic deformation of the inner pipe in the joint zone, then working pressure is applied, which causes reverse pipe deformation in the specified zone, the forward and reverse values being equal between by myself.