Pressure controlling and air lifting drainage gas recovery equipment and method

The invention relates to pressure controlling and air lifting drainage gas recovery equipment and method, in particular to equipment for achieving drainage gas recovery by combining the pressure controlling technology with the air lifting technology. The pressure controlling and air lifting drainage gas recovery equipment comprises an inner pipe (11), a middle pipe (9) and an outer pipe (8), wherein the inner pipe (11), the middle pipe (9) and the outer pipe (8) are embedded in a gas well and sleeved with one another. The inner pipe (11) is provided with an air lifting valve (7) and a pressure controlling valve (13). The pressure controlling valve (13) is connected with a pneumatic supply (1) and is capable of controlling the pneumatic supply (1) to work. In addition, the invention provides the method for collecting formation gas through the pressure controlling and air lifting drainage gas recovery equipment. By the adoption of the technical scheme, the pressure controlling and air lifting drainage gas recov