Patent ID: 7467911

Claim:
A gate system for attachment to a structure that has an opening through which fluid flows, the system comprising: a) a gate assembly having a gate portion designed and constructed to allow fluid flow therethrough while preventing the passage of particulate matter of a predetermined size and shape, said gate portion rotatable between a closed position and an open position relative to said opening, and biased to said closed position; b) at least one bracket assembly attached to said gate system on a side of said gate portion, said bracket assembly having at least one detent; c) a trip plate rotatably attached to said gate assembly and rotatable between a closed position and an open position, and designed and constructed such that sufficiently large fluid flow through said gate portion flows at least in part against said trip plate, said trip plate being biased to said closed position; d) said trip plate having at least one pin, said pin extending from said plate adjacent said bracket assembly; e) said pin communicating with said detent in said bracket assembly to hold said gate portion in the closed position until fluid flow against said trip plate causes it to rotate out of communication with said detent, thereby allowing said gate portion to rotate into an open position away from said opening.