Ball valve with all-welded valve bodies and welding method of ball valve

Abstract

The invention discloses a ball valve with all-welded valve bodies and a welding method of the ball valve. The ball valve comprises a spherical valve spool, a left valve body, a right valve body, a middle valve body, a valve stem, a valve seat, sealing rings, a press plate, a lining plate and the like. The ball valve is applicable to valve systems in gas and liquid delivery pipelines, and a high-frequency welding process is adopted to produce sealed parts. The spherical valve spool is placed in a spherical cavity in the middle valve body together with the lining plate, a thrust plate, a sliding bearing and the like, the sealing rings are mounted on the left and right sides of the spherical valve spool, the valve seat and a valve-seat support ring thereof are mounted on the inner walls of the valve bodies on the left and right sides together with an elastic mechanism, joint parts between the middle valve body and the left and right valve bodies are all sealed by welding, and one end of the valve stem penetrates the middle valve body and is connected with the internal valve spool. The valve stem rotates to drive the spherical valve spool in the cavity to rotate, so that the valve is controlled to be turned off. The ball valve is simple in structure, good in sealing performance, stable in welding and sealing quality, high in production efficiency and applicable to pipeline delivery systems for petroleum, natural gas and the like, and the problem of leakage of conventional valves is solved.

Description

technical field [0001] The invention relates to the technical field of valve manufacturing, in particular to a ball valve with a fully welded valve body and a welding method thereof. Background technique [0002] For long-distance oil and natural gas pipelines, not only the transmission pressure is high, but most of them are buried underground. Once a leak occurs, it is difficult to find and inconvenient to maintain. Therefore, the sealing performance, reliability and other performance parameters of the valves used in the pipeline are good. Damage directly determines the safety and efficiency of pipeline transportation. [0003] At present, ball valves with fully welded valve bodies are mostly used in the field of pipeline transportation. Due to their small fluid resistance, good sealing performance, fast switching and high reliability, they have become the new favorite in the field of valves. Although this kind of valve has greatly improved the leakage problem faced by tra...

AI Technical Summary

Problems solved by technology

Although this kind of valve has greatly improved the leakage problem faced by traditional gate valves, there are still many other problems. First of all, its submerged arc welding groove is in the shape of a straight groove or a V groove, which is not conducive to slag discharge, exhaust, and weld seam. It is easy to produce slag holes and pores, which affect the strength of the weld, the stress of the weld is concentrated, the residual stress in the heat-affected zone is large, and the thermal deformation of the weldment is large, which may cause stress cracks and shorten the service life of the valve. gap but not seal

Secondly, its valve seat is a two-body combined structure composed of a support ring and a piston assembly, which increases the volume of the valve seat and valve body; third, its valve cover is an integral structure, which makes the packing or sealing ring unable to be replaced; Fourth, the valve seat has only one sealing surface, and the sealing structure behind the seat is also realized by one or a group of sealing rings with equal diameters, and the sealing of the valve stem is also "external", which not only affects the sealing performance of the valve , also makes the sealing ring easily damaged, which affects the service life of the valve

[0004] At present, the welding method of fully welded ball valves is mainly automatic / semi-automatic submerged arc welding. During conventional welding, due to the short residence time at high temperature and fast heating speed, there is no corresponding follow-up treatment and then natural cooling. This uneven heating and The cooling process will inevitably lead to the generation of welding residual stress, which is not conducive to improving the quality of weldments

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