11 SSV HYDRAULIC OPERATED GATE VALVE PAGE 75 The SSV GateValve Actuator operates with hydraulic pressure. Pressure is applied to the top of the piston. This process is designed to open a normally closed (reverse) gate valve, or close a normally open gate valve. HYDRAULIC ACTUATED SLAB GATE VALVE (SSV) Upper Shaft Bonnet Cap Lower Shaft Upper Housing Springs Lower Housing Seat Gate Valve Body Vents Inlet Lube