Device and method capable of automatically filtering subway piston air

The invention relates to a device capable of automatically filtering subway piston air, and belongs to the technical field of subway platform doors. The device comprises a pressure sensing type automatic reel filter installed at the position of an air valve or a ventilation opening of a subway platform door; the pressure sensing type automatic reel filter comprises a feeding box, a discharging box, filter material reels, an automatic rolling shutter and a differential pressure sensor, wherein the feeding box and the discharging box are arranged in a shell frame; the filter material reels are arranged in the feeding box and the discharging box, filter materials are wound around the filter material reels, and the filter materials are located on one side close to a subway rail line area; theautomatic rolling shutter is arranged on one sides, facing a station inner waiting area, of the filter materials; and the differential pressure sensor is arranged on the filter materials. According tothe device, the pressure