D341W蜗轮通风蝶阀QD41W轻型通风蝶阀外形连接尺寸答:DN尺寸(直径):D341W: 300mm, 400mm, 500mm, 600mm, 700mm, 800mm, 900mm, 1000mm, 1100mm, 1200mm, 1300mm, 1400mm, 1500mm, 1600mm, 1700mm, 1800mmQD41W: 350mm, 450mm, 550mm, 620mm, 720mm, 820mm, 920mm, 1040mm, 1140mm, 1240mm, 1340mm, 1440mm, 1540mm, 1640m...