Dry pipe valve for fire protection sprinkler system

A differential-type dry pipe valve for a fire protection sprinkler system, comprising:

• a valve body defining an inlet and an outlet, a water-side chamber in communication with said inlet and an air-side chamber in communication with said outlet, and, therebetween, an air valve seat having an air valve axis and a water valve seat having a water valve axis,
• a clapper mounted to pivot about a pivot axis closely adjacent said air valve seat between a first, clapper-closed position for resisting flow of water through said water valve seat and a second, clapper-open position for permitting flow of water through said water valve seat toward said air-side chamber,
• an air valve seal mounted to said clapper for sealing engagement with said air valve seat with said clapper in said first, clapper-closed position, and
• a water valve seal mounted to said clapper for sealing engagement with said water valve seat with said clapper in said first, clapper-closed position,
• said air valve seat being centered a first radial distance from said pivot axis and said water valve seat being spaced a second radial distance from said pivot axis, said air valve seat and said water valve seat being asymmetrically arranged, with said first radial distance being greater than said second radial distance.