Hydraulic Actuators for Regulating Large and Quick-Stroking Time Valves

Emerson's Stefano Belletti


Author: Stefano Belletti

Process plants, not only in the oil and gas sector, are becoming increasingly complex in a competitive environment. Therefore, the performance of regulating and modulating valves is also an area where we need to focus our attention to improve the process and optimize costs.

Precision, reliability, speed of operation, and fail-safe capabilities are among the most critical aspects of the performance of regulating and modulating valves which are typically supplied with a pneumatic actuator and a smart pneumatic positioner.

However, for various applications, especially when large-sized valves are involved and/or when quick-stroking time (associated with a fail-safe action) are needed, pneumatic actuators can present complexities and challenges. These are because very high pneumatic flow rates are required to operate and that the pneumatic supply fluid to the actuator is compressible.

Bettis EHO Electro-Hydraulic Operator (Smart)While electric actuators can offer a partial solution since they present some limitation regarding quick-stroking time and fail-safe action, hydraulic actuators with dedicated hydraulic smart controls can now offer a valid alternative to pneumatic actuators in case of large valves and/or quick stroking time, associated with a fail-safe action.

In particular, the new generation of hydraulic smart controls present advanced features similar to pneumatic smart positioners and they can cover, in association with typical advantages of hydraulic systems, the most critical and demanding applications with diagnostic data collection, which is covering not only the valve+ actuator unit, but also to the integral hydraulic power unit (HPU) if present.

From Jim: Stefano will be speaking at the upcoming Valve World Expo in Düsseldorf, Germany. You can attend his presentation on hydraulic actuators at 10.40 a.m. in Room 2. You can also connect with more actuation experts in the Valves, Actuators & Regulators group in the Emerson Exchange 365 community.

Posted Monday, November 26th, 2018 under Actuator.