A hatch cover assembly includes a vent passageway through a hatch cover for venting the interior of a railroad hopper car, or the like, to the environment. The hatch cover is held in closed position by a locking strap, and the vent passageway is located directly beneath the locking strap to help prevent...http://www.google.sh/patents/US5158022?utm_source=gb-gplus-sharePatent US5158022 - Hatch vent assembly for railroad cars with baffle and screen mesh to prevent entry of contaminants
