Composite perforated subsoil drain with exterior filter strip - has pipe and fibrous strip fed from individual spools in same machine with filter wrapped found pipe by spiral funnel

摘要

The process is used in the installation of sub-soil drains effecting the simultaneous placement of a continuous perforated pipe (2) and a wrap round filter (3) in a trench (1). The filter prevents silt ingress, and is in the form of a strip whose width exceeds the pipe circumference. A travelling machine may provide separate spools (12, 15) from which the pipe and the filter are fed, with a tube (21) guiding the wrapped pipe directly onto the trench bottom. The filter may be introduced by a spiral section funnel (18) having traversed a curved slot in a guide plate (17).