Method and apparatus for encasing drainage pipes

摘要

Method and apparatus for encasing drainage pipes, using fibrous or particulate loose filler material guided onto the drainage pipe by means of a hollow screw and held there with a permeable envelope material preferably wound round with a filament. The pitch or number of threads on the screw, the height thereof and the speed at which the screw rotates determine the amount of filler material applied to the drainage pipe per unit of area. The apparatus comprises a machine consisting of a guide tube carrying an internal hollow screw, the drainage pipe being guided in the interior of the screw, the encasing envelope material being placed externally upon the said guide tube and preferably being wound around with a filament at the end of the screw.