US Patent 8469112 Dry sprinkler

A dry sprinkler for a fire protection system. The preferred dry sprinkler has a metallic disc annulus positionable within a passageway to skew a central axis of a face of the metallic disc annulus with respect to a longitudinal axis of the dry sprinkler so that an expected minimum flow rate based on a rated discharge coefficient is provided. The dry sprinkler operates to provide an expected flow rate over a range of start pressures. The expected flow rate is based on a K-factor rating. The dry sprinkler provides an acceptable level of fluid flow rate from the expected flow rate based on the K-factor for a range of start pressures.