The 79 Series flow control servo valves are throttle valves for 3 and preferably 4-way applications. These three stage servo valves were developed for applications that require high flow rates and high performance. The 79 series covers the range of rated flow from 30 to 200 gpm at 1,000 psi valve drop. These valves are offered with 76X Series pilot valves, in either Standard, High, or Very High performance configurations.

These valves are suitable for electrohydraulic position, speed, pressure, or force control systems with high dynamic response requirements.

An electrical command signal (set point, input signal) is applied to the external control amplifier which drives a current through the pilot valve coils. The pilot valve produces differential pressure in its control ports. This pressure difference results in a pilot flow which causes main spool displacement.

The position transducer, which is excited via an oscillator, measures the position of the main spool (actual value, position voltage). The signal then is demodulated and fed back to the control amplifier where it is compared with the command signal. The control amplifier drives the pilot valve until the error between command signal and feedback signal is zero. Thus, the position of the main spool is proportional to the electrical command signal.

• Electrical feedback on the main spool for low hysteresis and excellent linearity
• Optional external pilot supply and return connections
• High spool control forces
• High dynamics
• Rugged, long-life design
• High resolution, low hysteresis
• Completely set-up at the factory
• Excellent null stability