The invention aims at providing a gas extraction metering device, so as to solve or improve at least one of the above problems. The gas extraction metering device has an extraction assembly, a connecting assembly, and a metering mechanism. The extraction assembly has an outer pipe, a first inner pipe, and a clamping assembly.
The connecting assembly has a second inner pipe. The metering mechanism has a first metering assembly and a second metering assembly.
The outer pipe is fixedly connected to two plugs at both ends. The plugs have grooves that the first inner pipe passes through. The invention provides a method for metering dual-layer coal seam methane extraction, which can simultaneously drill holes and extract methane in coal seams of two horizons.
The invention can extract and meter methane of the two coal seams respectively in the same borehole, which is convenient for analyzing and monitoring the methane content and coal gas content of each coal seam.
The invention is simple in structure, accurate in measurement, convenient in installation and disassembly, small in occupied space and low in cost.
