Drainage system for expressing fibrous materials

Abstract

A drainage system for expressing liquids and fluids from fibrous materials. The system includes a plurality of spaced apart compression elements each retained in juxaposition one to another so as to have a fluid escape slot between each adjacent compression element. Each compression element has a longitudinal passageway therethrough each having an inlet and an outlet which is inwardly tapered toward its outlet. The combination of passageways through each compression element forms a compression conduit whose inlet and outlet generally functionally coincide with the intake and exit, respectively, of the drainage system. The fibrous material to be expressed is introduced into the system's intake under pressure, the fibrous material being compressed as it is forcably urged through each tapered passageway, the expressed fluids exiting the compression conduit radially outwardly through fluid escape slots. The slots, which may be dynamically variable in width, are sized to facilitate fluid escape or discharge, but to contain the fibrous material within the compression conduit. The preferred embodiment of the shape of each taper is a truncated cone whose nominal diameter may also vary along the length of the compression conduit to prevent build-up and cloging of the fibrous material as it passes through the drainage system. This concept of fluid discharge slot variability during operation is also applied to improvements in conventional screw press cage screen bars.