The utility model provides an air distributor, including distributor main part, first blank flange and second blank flange, the inside cavity of distributor main part, both ends have an opening, and distributor main part lateral wall has a plurality of trompils, and wherein an at least trompil is as the air inlet, and an at least trompil is as the gas outlet, and other trompils are as reserve air inlet or reserve gas outlet, each trompil department is equipped with the joint, first blank flange detachably connect in the one end opening part of distributor main part is with the shutoff the opening, be equipped with the relief outlet on the second blank flange, second blank flange detachably connect in the other end opening part of distributor main part, relief outlet and the inside intercommunication of distributor main part. The utility model discloses an among the air distributor, can change the export volume in a flexible way, simple structure maintains that the maintenance is light, work safe and reliable, and low cost, it is respond well.