欧美精品亚洲精品日韩国产_日韩无夜高潮大片AV_在线亚洲欧洲一区_亚洲AⅤ人无码激艳猛片服务器_朝鲜女人下边毛茸茸_欧美一级艳片视频免费观看_亚洲日韩在线激情另类专区_乌克兰肥妇黑毛bbw_久久人妻无码一区二区_无码中字日韩经典

     Loose flange of butt welding ring is a slip flange, which is generally matched with water supply and drainage fittings. There is a flange at both ends of the expansion joint, which is directly connected with the pipeline and equipment in the project by bolts.