Improvements in screens and methods of their manufacture

摘要

Screens with particular application as filters in a downpipe, and methods for their manufacture are disclosed. The screen (1) has a plurality of channels (7) that pass from an upstream side to a downstream side, where the openings of the channels on the upstream side are larger than the openings of the respective channels on the downstream side. More than 50% of the surface area of the upstream side is occupied by channel openings. In use, the screen is positioned on an incline in a fluid flow to separate out debris from the flow.