DRIVING STAGE FOR SAFETY VALVE, INDIRECT-ACTING MANUALLY-REGULATED SAFETY VALVE AND INDIRECT-ACTING PROPORTIONAL SAFETY VALVE Russian patent published in 1999 - IPC

FIELD: driving stages for safety valves. SUBSTANCE: stage includes axially movable valve gate bounding the valve chamber on one side forming seat for valve taper shut-off lock. Valve gate forms active surface in pressure chamber whose magnitude considerably exceeds free transversal section of valve seat. When pressure chamber is loaded with pressure, valve gate is acted on by hydrostatic force opposing to closing force of adjusting compression spring. Body stop determined first axial final position of valve gate in direction of this hydrostatic force. EFFECT: improved qualities of stage both in manually-regulated safety valves and in proportional safety valves. 9 cl, 7 dwg