Top entry ball valve body cavity has high precision valve hole, because they have to cooperate with the valve seat sleeve 0-ring, so fine A general admission HS level, the surface roughness Ra value should be less than 1.65m. In the upper part of the body cavity and the valve cover has a spigot cooperating, fine Zhuang for I VIVA, level, surface roughness Ra value of less than 3. 25m. Another connection with the valve cover bolt hole and is threaded for fine quality thread 6H level, the surface roughness Ra value should be less than 6.35m. At the bottom of the valve body has a bearing bore and bearing with the lower stem, Liaoduo is H9, a surface roughness Ra value is lower than 3.25m. The valve cover has a bearing hole cooperating with stem bearing, and the precision of the valve packing or 0-ring sweep mating hole, the hole is H8 level, should be lower than the value of the surface roughness Ra 1.65m, and have the A bolt hole of the valve body into contact, with the hole perpendicular to the bottom surface of the valve cover is not greater than 1 °. Wenzhou Frank Valve Co., Ltd. Address: Wenzhou Yongqiang Hi-Tech Industrial Development Zone of the Hill Industrial Park Road 59 macro Tel: 0577-86939928 Fax: 0577-86930999 Contact: Manager Wu phone: 18067796085 QQ: 1450086854 E-mail: 1450086854@qq.com American Standard Ball: http: //www.lankevalve.com due to the implementation of standards and American Standard ball valve GB structural differences in the design, so the two will be the difference in the price, so when purchasing, please Phone us directly.