498 Parker Hannifin Corporation Fluid Control Solutions Europe General Catalogue FCSE/0112/UK V2.2 07/2022 PILOT OPERATED VALVE To control a higher flow, it is necessary to use pilot operated valves. The supply pressure enters the direct operated "pilot stage" which directs the flow to a "pilot chamber" which,in turn, applies the pilot pressure over a large area (generally a diaphragm or piston). Therefore, a large force is generated to move the main sealing elements against higher pressure or over a large orifice. One condition of operation is to have a minimum pressure available to shift the valve (indicated in the catalogue). In most applications, this presents no particular problems (refer to magnalift valve section). The pressure rating of the valve starts between 0.1 to 0.5 bar (depending on the valve). (NB. Pilote Operated Valves are also called Servo Operated Valves). Pilot Operated Valve De-energised Energised Example: • 321 Series • 7321B Series TECHNICAL INFORMATION
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