Combined sealing structure with pressure compensation

Abstract

The invention discloses a combined sealing structure with pressure compensation. The combined sealing structure is applicable to a full rotary type underground rotary steering drilling tool. A connecting ring is mounted at the left end of a seal cartridge in an interference fit manner; the right end of the connecting ring is welded with the left end of a metallic seal corrugated pipe; the right end of the metallic seal corrugated pipe is welded at the left end of a pressure cylinder sleeve; a safety valve is arranged at the leftmost end of the pressure cylinder sleeve; a one-way valve is arranged on the right side of the safety valve; the interior of the pressure cylinder sleeve and a piston are in interference fit; the piston is in interference fit with a guide shaft at the same time; the right end face of the piston is welded with the left end of a spring; the right end of the spring is welded at the left end face of a spiral seal; the spiral seal sleeves the guide shaft in an interference fit manner; the right end of the spiral seal is positioned through a spring collar; the connecting ring mainly seals drilling fluid entering from the movable space of the guide shaft and interior lubricating oil; the spring seal and the piston jointly seal the drilling fluid entering from the spiral seal structure and the interior lubricating oil; the spiral seal filters the solid particles in the drilling fluid. The combined sealing structure has the characteristics of high temperature resistance, high pressure resistance, corrosion resistance, impact resistance, wear resistance, high sealing property and long service life.

Description

technical field [0001] The invention relates to a seal suitable for a full-rotation pointing rotary steerable drilling tool, in particular to a combined sealing structure with pressure compensation. Background technique [0002] The sealing of the steerable drilling tool is mainly to solve the sealing problem between the rotating casing or the non-rotating casing and the mandrel. The seals commonly used in rotary steerable drilling tools mainly include packing seals and lip seals. These two sealing forms are mainly realized by compressing the sealing material to produce large deformation, which is difficult to meet the controllable bend joint rotary steerable drilling tools in different drilling modes. The performance requirements for the sealing structure under harsh working conditions are mainly reflected in the following points: [0003] 1. The sealing surface has a swing angle within the design range, so the sealing structure needs to realize the seal while leaving an a...

AI Technical Summary

Problems solved by technology

[0007] Because it is difficult for the packing seal to achieve radial compensation when the sealing surface swings, and it wears faster near the gland; the lip seal is difficult to meet the sealing requirements when the pressure difference on both sides of the sealing surface changes irregularly, and the high temperature underground In the environment of high-pressure and high-abrasive drilling fluid, it is difficult to achieve a sealing effect

Therefore, packing seals and lip seals are difficult to meet the above-mentioned requirements for the sealing structure of rotary steerable drilling tools with controllable bend joints

Images