短語詞組短語blow -down valve 排氣閥;排污閥;排放閥;排水閥sequencing blow -down valve 順序排污閥surface blow -down valve 上排污閥boiler blow down valve 鍋爐排污閥BLOW DOWN VALVE BDV 排空閥bottom blow down valve 底部排污閥BDV blow down valve 放泄閥;疏水閥 返回 blow down valve