Inner expansion connecting structure for screw sleeve type steel and plastic composite pipe

Abstract

The invention discloses an inner expansion connecting structure for a screw sleeve type steel and plastic composite pipe, which comprises a threaded sleeve and a clamp sleeve in coaxial parallel arrangement, wherein a screw sleeve for regulating the distance between the threaded sleeve and the clamp sleeve is sheathed outside the threaded sleeve and the clamp sleeve, the end part of the threaded sleeve far away from the clamp sleeve and the end part of the clamp sleeve far away from the threaded sleeve are respectively provided with inwards projected annular shoulders in the radial direction, two pipelines requiring the butt joint respectively extend into the structure from the annular shoulder parts of the threaded sleeve and the clamp sleeve, annular expansion bulges are respectively and outwards expanded on the extending sections of the two pipelines requiring the butt joint in the radial direction, the two expansion bulges are respectively and tightly butted on the two annular shoulders, an lining sleeve sheathed outside the two pipelines requiring the butt joint is rightly butted and arranged between the two expansion bulges, both sides of the expansion bulges are respectively butted by the end parts of the annular shoulders and the lining sleeve, the expansion bulges can not easily generate and recover the deformation to disconnect the pipeline even when the pipeline receives excessive disconnecting force, and the anti-disconnecting capability of the connecting structure is effectively improved, simultaneously, the expansion bulges can not easily generate the deformation, the position of a pipe opening is relatively fixed, and the sealing is more reliable.

Description

Technical field [0001] The invention relates to a pipeline sealing connection structure, in particular to a sealing connection structure of a steel-plastic composite pressure pipe. Background technique [0002] Steel-plastic composite pipe is a new type of composite pipe. It has the advantages of strong pressure bearing capacity, good corrosion resistance, and low linear expansion coefficient. At present, it has been increasingly used in oil and gas transportation, industrial and mining pipes, Various fields such as drinking water pipes and drainage pipes. [0003] In order to solve the problem of rapid sealing connection of steel-plastic composite pipes, a variety of connection structures have been proposed in the prior art. Among them, the expansion connection structure is not reduced in diameter, has strong pull-out resistance, reliable sealing, and easy disassembly and assembly. The advantage has become the most widely used connection structure. The existing expansion connect...

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Problems solved by technology

[0003] In order to solve the problem of fast sealing connection of steel-plastic composite pipes, various connection structures have been proposed in the prior art. Among them, the structure of expansion connection has the advantages of no diameter reduction, strong resistance to pulling out, reliable sealing, and easy disassembly. The advantages become the most widely used connection structure. The existing expansion connection structure generally uses a threaded ring and a snap ring to imprison two pipes to be connected with expansion protrusions, such as the patent ZL200510113148.7 "steel-plastic composite pressure However, the above-mentioned expansion connection structure still has the following two disadvantages: 1) The pull-out force is limited by the strength of the steel pipe in the steel-plastic composite pipe. When the pull-out force is too large, the expansion The protrusion may still be squeezed and deformed to return to the size of the normal pipe diameter, causing the pipe connection to be disengaged; 2) Even if the expansion protrusion does not fall off under the action of the pull-out force, it is easy to produce small deformation, which will damage the pipe connection. The sealing has adverse effects. When the pipeline is used for hot water, high-pressure medium, etc., it is easy to leak

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