Shut-off valve for natural gas wellhead

Abstract

The invention discloses a cut-off valve for a natural gas wellhead. The cut-off valve comprises a valve body. The valve body is provided with transversely penetrated flow passages and a vertically arranged valve chamber communicated with the top of the valve body. The valve chamber divides the flow passages into an inlet flow passage and an outlet flow passage, and the valve chamber is provided with a vertically movable valve plate. The upper end of the valve plate is connected to a valve stem, the upper end of the valve stem protrudes from the top of the valve chamber, a seal packing is arranged between the valve stem and the valve body, the inlet flow passage is communicated with the upper portion of the valve chamber through an inlet auxiliary flow passage, and the valve body is provided with an auxiliary flow passage stopper capable of closing or opening the inlet auxiliary flow passage. According to the cut-off valve for the natural gas wellhead, through the modification of the valve body and the valve plate structure, the auxiliary flow passage stopper opens the inlet auxiliary flow passage when the valve plate is closed, the natural gas with a certain gas pressure enters theupper portion of the valve chamber through the inlet auxiliary flow passage, and the natural gas becomes the power for driving the valve plate to move downward so that the valve plate is stably and firmly pressed at the bottom of the valve chamber and the valve can better achieve the effect of blocking and meet the on-site requirements.

Description

technical field [0001] The invention belongs to the technical field of natural gas exploitation, and in particular relates to a cut-off valve for a natural gas wellhead. Background technique [0002] At present, in the production of natural gas wells, after throttling is performed downhole or at the wellhead, the surface gas transmission pipeline adopts a medium-pressure design. The rupture of the downstream pipeline causes a large amount of leakage of natural gas. Therefore, a closure device with high and low pressure protection functions must be installed at the natural gas wellhead. At present, wellheads generally use gate valves or other similar devices to realize this function, such as the Chinese patent whose authorized announcement number is CN102373899 B: the opening and closing of natural gas wellhead pipelines, which discloses a self-energy passing through the medium in the valve body. The chamber and the lower chamber have different contact areas with the medium,...

AI Technical Summary

Problems solved by technology

At present, wellheads generally use gate valves or other similar devices to realize this function, such as the Chinese patent whose authorized announcement number is CN102373899 B: opening and closing of natural gas wellhead pipelines, which discloses a self-energy passing through the medium in the valve body. The chamber and the lower chamber have different contact areas with the medium, forming a power opening and closing valve that lifts the spool. It is characterized in that it can open and close the valve without using electricity, but its sealing effect will inevitably decrease with the thickness of the spool. Small, there is a certain risk; at the same time, the internal structure of the valve body is quite complicated, and it is very difficult to process. In many cases, its role is relatively limited and cannot meet the needs of the gas field.

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