Exclusion of small animals from drainage pipes - involves device with swinging arms forming grid which does not impede flow of water

摘要

The device prevents small animals from entering drainage pipes, but does not impede the flow of water in the opposite direction. The device consists of a circular housing (1) with internal ribs (2,2'). These ribs project axially from one end of the housing. Slots (5) in these projections receive pins (4) which support swinging arms which normally hang vertically and form a grid which obstructs the passage of the animal. The grid offers no resistance to the flow of water or to any solid matter suspended in the water as the ribs swing upwards to the horizontal position to allow the solid matter to pass through. USE - Drainage systems, sewers etc.