APPARATUS FOR THE MANUFACTURE OF A PREASSEMBLED DRAINAGE LINE UNIT

摘要

A preassembled unit for a sewage nitrification field has minimum outward dimensions of loose, lightweight plastic aggregate material enveloped and bound by a plastic slee ve around a horizontal conduit. In one embodiment, the unit takes a bag form with an aggregate-filled nettin g sleeve concentrically surrounding and fastened to the ends of corrugated plastic vent pipe. In another form, the sleeve is a plastic extrusion of rectangular cross-section and the conduit can be formed integrally with the sleeve. Cross-webbing is added for strength. In ground installation, conduitless uni ts make up the insufficiency of aggregate dimension. Mating male and female end caps are used to interconnec t the conduit of adjacent units end-to-end. Apparatus for manufacturing the concentric netting sleeve/vent pipe version has a hopper that discharges aggregate into the top of a mandrel and an annular disc or helica l auger blade that pushes the aggregate forward into the sleeve.