Valve actuator design case study
Brief: Build a fast acting failsafe stop valve actuator for a plant firefighting system. The actuator needed to be compact and pneumatically operated, with no springs for the failsafe function.
The addition of a conventional accumulator would have exceeded the dimensional constraints of the specification, so Rotork-Hiller engineers incorporated the accumulator with the pneumatic actuator. The design freed up additional space for mounting the controls to the actuator. These controls include filters, regulators, solenoid valves and pressure switches, contained within overall actuator dimensions of 470 x 584 x 680 mm.
The controls reduce the customer’s supply pressure of 45 barg (652 psig) to 31 barg (450 psig), which is pumped into the accumulator to provide approximately 4.4 ltrs of storage capacity. The actuator delivers a maximum thrust of 26 617 N (6209 lbs).
‘One of the best features of this design is the pneumatic system redundancy with the ability to support the failsafe function of the valve in a simplified stand alone package’, commented Rotork-Hiller’s Engineering Manager. ‘The integration of the nitrogen storage accumulator with the actuator body itself can be further developed and potentially applied to all existing Rotork-Hiller failsafe pneumatic designs’.
Adapted from a press release by Emma McAleavey.
Read the article online at: https://www.hydrocarbonengineering.com/product-news/18032014/rotork_hiller_valve_actuator27/