DesignThe Hallite 71 single acting fluid seal assembly consists of the standard Hallite 18 single acting fluid seal and the Hallite 62 L shaped bearing ring (wear ring). Manufactured in very hard wearing polyacetal resin, the bearing ring was originally designed to replace conventional bronze or cast iron piston bearings, reducing the problem of cylinder bore scoring to a minimum and allowing the designer to use compact, strong, cost effective steel pistons. The inherent nature of the material enables it to settle to the bore size once it has been pressurized, therefore providing an excellent anti-extrusion member and also increasing seal life.Due to its flexibility it should not be used primarily as a bearing where severe knuckling or excessive side loading may occur. Under these conditions we suggest the use of conventional bronze or cast iron bearings or the additional use of the Hallite 506 bearings. The proportions of the range have been determined to give a satisfactory performance when used with the recommended operating conditions.Other sizes are available outside this range.