METHOD AND APPARATUS FOR LINING MANHOLE ASSEMBLIES AND THE LIKE

摘要

Each section of a manhole assembly is cast in a mold which incorporates a mesh-like wire cage superstructure, employed to enhance the structural strength of the cast member, and liner sections joined end to end about the interior of the cast member by a slide-on clip structure which locks flanges of adjacent liner sections and compresses a gasket therebetween to assure a liquid-tight interior. The liner sections are produced from a low density polyethylene material using a rotocasting method capable of forming sturdy reenforcement ribs providing superior structural strength to maintain and retain the shape of the liner sections. Ties are passed through openings provided in the reenforcement ribs and looped around the members of the wire reenforcement cage structure to assure proper alignment of the liner sections as well as permanent anchoring of the liner sections to the cast material. Mounting mandrels are employed during the casting operation to maintaining proper positioning of a gasket and the liner sections and to retain the gasket in proper position within the hole defined by the mandrel. The liner material in inert to corrosive forces. Top liner and manhole extension members, also formed utilizing the rotocast method, protect the upper regions of the manhole assembly. The extension member cooperates with the top liner to provide a height adjustable water-tight seal for cast material between the top liner and grade level.