常见例句Some wrench-operated valves, specifically those used in ammonia and amines service, have packing nuts with notches machined into the flats.一些扳手型閥門，特別是那些用於氨和胺設施的扳手型閥門的襯墊螺母帶有加工進平麪的凹槽。 返回 packing nut