Patent ID: 7322423

Claim:
A fire protection system comprising: a supply pipe having a first fluid pressurized to a first pressure; a network of pipes having a plurality of sprinklers, the network of pipes having a second fluid being pressurized to a second pressure at approximately 5.5 times the first pressure; and a dry pipe valve including: a body defining a passage extending along a longitudinal axis between an inlet coupled to the supply pipe and an outlet coupled to the network of pipes, the inlet having an inlet diameter of approximately WD inches; a seat disposed in the body, the seat having a seating surface with a diameter AD approximately less than two times WD inches; and a clapper pivotable about an axis orthogonal to the longitudinal axis between a first position occluding the passage when the ratio of the second pressure to the first pressure is at least 5.5 and a second position permitting fluid flow through the passage when the ratio is less than 5.5, the seat disposed relative to the inlet such that the second pressure is sufficient to independently seal the clapper in the seat in the first position against the first pressure when the ratio of the second pressure to the first pressure is at least 5.5.