Rotary Servo Valve

The servo valve has four ports: Supply, two Control Ports, and Drain/Tank. With

the hydraulic valve in its middle position, all ports are blocked. As the valve

rotates, the supply is connected to a control port while simultaneously connecting

the drain to the other control port. The combined action of the servo position

controller and cylinder position controller modulate the power cylinder position as

necessary to match the input demand.

Additionally, the Remote Servo has an OVBD (Over Board Drain) port which is

permanently connected to drain. This port can (optionally) be connected to the

OVBD connection on Hydraulic Power Cylinder to drain any leakage pass the

primary rod seal.

A unique function of the software is a periodic, symmetrically opposed impulse

which flushes silt and debris from the servo valve without causing undue wear

called “Silt Buster”. At the interval and amplitude selected by the user, this

function provides a very rapid motion of the hydraulic valve allowing any silt to be

flushed to the drain passage. This motion is followed immediately by a step of

equal amplitude in the opposite direction. The opposing symmetry of the impulse

results in no net change in fluid volume to the controlled servo valve, and thus

does not interrupt the control of the turbine. This unique function provides a

higher degree of stability, reliability, and silt resistance.