短语词组短语piston compressor ring valve 压缩机环状阀supply valve piston ring [铁路]供给阀鞲鞴涨圈large main valve piston ring 主阀大活塞环Main valve piston large ring 主阀鞲鞴大涨圈Piston Ring for Control Valve 控制阀用活塞环 返回 piston valve ring