Controlling and Regulating with Continuous Directional Valves – for Reliable Turbine Operation

Content
Continous directional valves

To have the capability of actuating the adjustment devices in a turbine via control and regulation systems is a fundamental requirement for achieving high availability and reliability.

A wide variety of continuous directional valves, with and without integrated valve electronics, is available for hydraulic control and regulation systems. Customers can also choose from digital continuous directional valves for suitable applications as an alternative to this classic valve technology with analog command value input.

Directional Servo Valves

Directional servo valves are used in hydraulic actuators when short response times are required in conjunction with dynamic closed control loops. Double piloted directional servo valves consist of a torque motor in redundant design realized by two or three coils and a hydraulic amplifier. This electrohydraulic amplifier converts an electronically defined valve command value to a hydraulic power signal for adjusting the valve piston. In order for the valves to function, the hydraulic oil in the system must have a high level of cleanliness.

Directional Control Valves

A very good alternative to directional servo valves are directional control valves. Since the controlling does not take place via an electrohydraulic amplifier but directly via control solenoids, the resistance to contamination is considerably higher.

The dynamic properties of directional control valves are almost as refined as those of directional servo valves.

Proportional directional valves

Proportional directional valves are similar to directional control valves by design. The dynamic performance of these valves is in line with controlled applications. They can also be used as proportional throttle valves in turbine gears, for example.