US Patent 7575658 Vacuum washer drum

A vacuum drum washer is designed to enable the use of an end-draining drum for drum lengths exceeding 20 feet. The drum washer includes a cylindrical drum having a mesh screen defining an exterior wall. A plurality of outer filtrate channels are disposed radially inward from the mesh screen. A plurality of inner filtrate channels are disposed radially inward from the outer filtrate channels and extend along generally less than an entire length of the drum. A transfer channel connects the outer filtrate channels and the inner filtrate channels. A plurality of radial drainage chutes are disposed adjacent a head end of the outer and inner filtrate channels, which direct the filtrate to a drain valve.