短语词组短语steam damping -drum drier 蒸气干燥primary steam -drum 一次汽鼓steam -separating drum 蒸汽分离包steam drum water -level 汽包水位single -drum steam generator 单鼓式蒸汽发生器four -drum steam hoist 四滚筒蒸汽提升机high -pressure steam drum 高压汽包 返回 steam drum