Downward coal seam gas pressure measuring and hole drilling automatic water drainage device

Abstract

The invention discloses a downward coal seam gas pressure measuring and hole drilling automatic water drainage device which is composed of a water drainage pipe orifice automatic control valve, a gas guide pipe, a shock pipe, a hole drilling and sealing structure, a pressure measuring pipe, a piezometer, a piezometer rear valve, a tee joint, a piezometer front valve and a water drainage pipe. The water drainage pipe orifice automatic control valve is composed of a fixed pipe, an elastic membrane, a sealing pad, a gas cavity and an adjustable support. Opening and closing of the water drainage pipe are controlled by utilizing unequal stress on two sides of the elastic membrane, gas pressure difference outside a pressure measuring gas chamber and a drilled hole and a capillary structure are utilized as water drainage power of the water drainage pipe, water drainage speed is controlled by utilizing small pipe diameter of a capillary, the outside of the pressure measuring gas chamber and the water drainage pipe is constantly in a water sealing state in the whole process of water drainage, and gas leakage of the pressure measuring gas chamber is avoided, so that reliable, continuous and slow water drainage is realized without water drainage power.

Description

technical field [0001] The invention relates to the technical field of mine gas prevention and control, and is applicable to the drainage of underground pressure measuring boreholes in coal mines. Background technique [0002] Gas pressure is an important parameter to measure the occurrence of coal seam gas, and it is also one of the basic parameters that must be mastered in the coal mine production process. On-site testing is the basic method to obtain gas pressure. When water is contained in the piezometer borehole, the pressure measurement result will be inaccurate. Since it is difficult to know the water volume in the piezometric chamber and whether there is water column in the piezometric tube in the downward piezometric borehole, It often leads to a large error in the measured pressure, or even a failure of the pressure measurement. The main method to eliminate the impact of water in downward pressure measurement drilling is to use pumping devices to pump out the accu...

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Problems solved by technology

On-site testing is the basic method to obtain gas pressure. When water is contained in the piezometer borehole, the pressure measurement result will be inaccurate. Since it is difficult to know the water volume in the piezometric chamber and whether there is water column in the piezometric tube in the downward piezometric borehole, It often leads to a large error in the measured pressure, or even a failure of the pressure measurement

The main method to eliminate the impact of water in downward pressure measurement drilling is to use pumping devices to pump out the accumulated water in the borehole, but the control of the timing of pumping is critical. Once the gas in the pressure measurement chamber is discharged by mistake, the pressure measurement process will be prolonged. Even manometric failure

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