同根派生 packing nut相关词英汉例句Some wrench-operated valves, specifically those used in ammonia and amines service, have packing nuts with notches machined into the flats.一些扳手型阀门，特别是那些用于氨和胺设施的扳手型阀门的衬垫螺母带有加工进平面的凹槽。packing nut更多例句