US Patent 12025239 Dry pipe valve

Differential-type dry pipe valves for fire protection systems are provided. The valve includes a body with a clapper assembly disposed in an internal passage of the valve body between an inlet and an outlet. The clapper assembly is movable between a closed position and an open position to respectively prevent and permit fluid flow through the passage from the inlet to the outlet. With the clapper assembly in the open position, an internal mechanism is positioned to stop the clapper moving to the closed position. The valve includes a resetting assembly having a knob exterior to the body. Translation of the knob toward the outlet moves the internal mechanism which permits the clapper assembly to move to the closed position.