Roof forced ventilation and purification device

The utility model relates to the field of roof covering layers of ventilation devices, in particular to a roof forced ventilation and purification device. The roof forced ventilation and purification device comprises an integral frame (5), a roof ventilation clerestory (6) and a roof (7), and is characterized by further comprising a centrifugal fan (1), a bag type dust collector (2) and a gas ash conveying machine (4), the gas ash conveying machine (4) is arranged at the bottom of the roof ventilation clerestory (6), an air inlet of the gas ash conveying machine (4) penetrates through the roof ventilation clerestory (6), and the bag type dust collector (2) is erected on the upper portion of the gas ash conveying machine (4). An ash inlet of the bag type dust collector (2) is connected with an ash outlet of the gas ash conveying machine (4), the centrifugal fan (1) is arranged at the top of the bag type dust collector (2), and an air inlet of the centrifugal fan (1) is connected with an air outlet of the bag t