Electro-hydraulic actuators are devices that operate a valve through pressurized hydraulic fluid, however, their main source of energy is solely electrical. The electrical power supplied is used to energise a motor that runs a hydraulic pump which then supplies the pressurized fluid to operate a hydraulic actuator which controls the valve.

The complete system is self-contained, eliminating the need for a separate hydraulic power unit, simplifying system construction and improving safety and reliability.

A self-contained electrohydraulic actuator can be used with linear or rotary valves, the need for its use will depend on the requirements of the application. These devices are ideal for operating valves that need large torques or thrusts, or where fail-safe systems or high operating speeds are required.

Cowan Dynamics offers a line of electrohydraulic linear actuators, which are compact, self-contained devices that have a thrust capacity of up to 282,600 in-lbs’ plus an on/off and modulating service. It also has a line of electrohydraulic rotary actuators, E2HR, which have a torque capacity of up to 300,000 in-lbs’, as well as an on/off and modulating service.
Both lines of actuators provide safe valve closure, speeds of up to 20 degrees per second for rotary or 1 second per inch for linear and very low power consumption.