primary valve lever 充油阀杆

primary valve prolapse 原发性瓣膜脱垂

primary throttle valve 主节流阀 ; 初次节流阀

primary pilot valve 调速器主滑阀

primary steam safety valve 一次蒸汽安全阀

primary steam isolation valve 一次蒸汽隔离阀

converter primary regulator valve 变矩器初级调节器阀

primary pressure relief valve 主安全阀