船用空气管头-压载舱透气帽 Air pipe head - ballast tank cap 压载舱空气管头-压载舱透气帽 形式分为： A,AS型帽式空气管头-帽式透气帽-帽式空气帽 Cap type air pipe head cap cap type air cap B/BS型鹅颈式空气管头-鹅颈式透气帽-鹅颈式空气帽 Gooseneck type air pipe h
