Air pressure self-balancing check valve

Abstract

The invention discloses an air pressure self-balancing check valve used for liquid drainage of a well liquid gaining machine with a gas well. The structure includes that a valve plate is provided with a plurality of valve pins, the upper end of each valve pin is provided with a seal ring and is arranged in a valve groove, and the valve pins are capable of moving up and down along with the valve plates in the valve grooves when the valves move. The valve plate is tightly pressed on a valve seat through a seal compressed spring, and a through hole is formed in the valve seat. The total area of the through hole which is formed in the valve seat is equal to the total area of a valve pin hole. When no liquid is drained, the force on the valve seat is equal to the pressure applied by the seal compressed spring. When liquid is drained and when the upward pushing force on the valve plate exceeds the downward pressure on the valve plate, the check valve is opened, and well liquid is drained from the down-mine to the ground through the check valve. The air pressure self-balancing check valve is simple in structure, is capable of achieving seal of gas, avoids the problem that the born tensile force of a liquid drainage steel wire rope is overlarge caused by the fact that the pressure of the seal compressed spring is overlarge when liquid is drained, is specially suitable for borehole operation of an oil well, a coal well, a coal-bed gas well and the like, and guarantees safety.

Description

technical field [0001] The invention relates to a liquid single-flow valve for liquid drainage of an underground well fluid fishing machine, which is especially suitable for oil well extraction, coal well drainage, coal bed gas well drainage and gas recovery, etc., and is used to control the one-way flow of liquid flow and Play a role in the sealing of downhole gas. Background technique [0002] At present, in the process of oil well, coal well, coalbed methane well and other gas-bearing well fluid extraction and drainage, valves that can not only conduct flow in one direction but also prevent gas leakage are needed. The sealing spring of the commonly used check valve has a small rigidity, and only a small liquid pressure is needed to push the sealing spring to open the check valve and realize the one-way flow of the liquid. In the process of pumping liquid in gas-bearing wells, due to the effect of downhole gas pressure, the check valve is easily pushed open by the gas, re...

AI Technical Summary

Problems solved by technology

In the process of pumping liquid in gas-bearing wells, due to the downhole gas pressure, the check valve is easily pushed open by the gas, causing gas leakage and causing harm

In order to effectively prevent the leakage of downhole gas, especially to ensure the safety when there is a large amount of high-pressure gas in the downhole, it is necessary to increase the stiffness of the sealing spring to ensure a sufficient safety margin, but this in turn requires a greater liquid pressure to Opening the check valve increases the difficulty of draining and affects the service life of the system

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