短语词组短语seal catch ring 密封挡环Seal Shim Ring 阀盖环C seal -ring C形密封圈seal retaining ring 密封固定环seal case ring 密封箱圈seal protector ring 密封防护垫环seal wiper ring 封闭刮油环INTERNAL SEAL -RING 内部密封环seal packing ring o 形密封圈 返回 seal ring