Pneumatic & Hydraulic Actuators

Pneumatic and hydraulic actuators use air or oil pressure to operate valves quickly and reliably, with spring-return versions for fail-safe action. Seven Star LLC, an independent supplier in Muscat, supplies pneumatic and hydraulic actuators from Masoneilan, Biffi, Bettis, Fisher, IMI STI, Rotork, Air Torque, SAMSON, Bray, Flowserve and EBRO to customers in Oman and the GCC.

Types of pneumatic actuator in this category

Spring-diaphragm actuators such as the Masoneilan 87/88, 37/38 and 81/82, Fisher 657 and 667 and SAMSON Type 3271 and 3277 drive globe control valves. Piston actuators like the Masoneilan 51/52/53 and Fisher 1061 give higher thrust. Rack and pinion actuators (Biffi RPD and RPS, Bettis RPX, Bray 92/93, Air Torque, Rotork CP) suit smaller quarter-turn valves, and scotch yoke actuators such as the Bettis G and CBB series, Bray Series 98, IMI STI RTC and RTQ, Rotork GP/GH and Flowserve Automax deliver high torque for large valves. Hydraulic versions like the Biffi OLGA-H and Rotork Skilmatic serve remote and fail-safe duties.

How to select a pneumatic actuator

Calculate the valve torque or thrust with a safety margin at the minimum supply pressure. Choose double-acting or spring-return and the fail direction, then the stroke time. Specify supply medium and pressure, temperature range, mounting to ISO 5211 or the valve yoke, and accessories such as positioners, solenoid valves, limit switches and manual overrides.

Data needed for a quotation

Send the actuator model and size, or valve type, torque or thrust, supply pressure, fail action, accessories and quantity.