Patent ID: 8251611
Filing Date: 2012-08-28
Classification: E02B,Y10T

Abstract:
1. A preassembled drainage unit comprising a longitudinally extending sleeve comprised of a combination of netting and barrier, wherein the netting is shaped to contain aggregate; wherein the barrier is a sheet of material for resisting passage of fine solids from the exterior of the drainage unit into the aggregate contained within the sleeve, and wherein the barrier sheet forms a portion the exterior of the drainage unit where the barrier sheet is present, the barrier sheet having (a) a fixed first sheet portion extending lengthwise and circumferentially on the outer surface of the drainage unit; and (b) two movable second sheet portions, each second sheet portion running along an opposing lengthwise side of the first portion as a flap which is foldable laterally with respect to a lengthwise direction of the first portion and the exterior surface of the drainage unit; and the lightweight aggregate contained within the sleeve.