ProAct
General. The Alpha Thames range of electric actuators have been developed over time and currently employ many common standard parts across the various actuators. For example the same compact permanent magnet DC brushless torque motor and drive system is used on all actuators. All actuators are oil filled and pressure balanced to operate at the ambient pressure. They are designed for close coupling to the valve through the valve bonnet and are capable of operating the valve under all conditions as outlined for the different actuators below. Position monitoring of the actuators is provided and is independent of the motor.
PROAct is a fast acting pressure balanced, subsea electric linear actuator for the modulation of flow control valves. PROAct is the first subsea electric actuator available for modulating control valves. This actuator is positioned to control oil, gas or water outflow from the separation unit.
When coupled to a suitable flow control valve, its speed of response make it ideally suited to maintaining the liquid level in a separation vessel. The speed of the actuator is
able to cater for normal operation as well as for start-up and shutdown conditions and
rapid changes in the process level due to short-term discontinuities in the process.
Closed-loop control is achieved by means of a suitable feedback sensor, giving
continuous process control. Under failure conditions the static line pressure will fully
open the valve and allow process functions to continue, albeit without the control from
that particular actuated valve.
In a System-Module, which has three-phase separation, a PROAct actuated valve would be required for each of the following functions to:
- Maintain water level
- Maintain oil level
- Control gas and separator pressure.
Although already test proven, PROAct is undergoing a series of endurance testing which is proving the capability of the actuator for prolonged use subsea.