Guidable valve and adjusting method

The invention relates to a guidable valve and an adjusting method. The guidable valve consists of an air valve blade, an air valve blade rotating shaft and a worm-gear pair, and is characterized in that the a worm spindle of the air valve blade is arranged on a position, adjacent to the air outlet side of an exhausting pipe, of the a secondary air return pipe, an air valve blade shaft is fixed at one side of the air valve blade or on the edge of the blade, when the air valve blade is opened, one end, away from the worm spindle of the air valve blade, of the blade extends to the exhausting pipe to form an adjustable angle with the air inlet direction, and an effect of a guide plate is realized. Therefore, the air is exhausted by virtue of the inertance, partial exhausted air flows into the secondary air return pipeline, the secondary air return can be realized without closing an exhausting valve, the exhaustion smoothness of the entire machine is not affected, the negative pressure of a drying box is not reduced, the drying quality of the device is guaranteed, and the energy of the entire machine is saved.