Canadian actuator manufacturer Cowan Dynamics has engineered and delivered a custom SIL 3-certified Scotch-yoke actuator system for China's $20 billion Yulong Island Refining and Chemical Project: 90-degree rotation, spring-return fail-open design, spring-fail torque of 2.7 million in.lbs (approx. 305,000 N·m) — with the full stroke completed in under 31 seconds on an available air supply of just 50 psi (approx. 3.4 bar). The system incorporates Topworx technology for partial stroke testing (PST) and emergency shutdown (ESD). The complete assembly measures 13.5 meters in length. Compiled from Valve World (2026-10-09).
Cowan Dynamics custom scotch-yoke actuator (image: Valve World / Cowan Dynamics)
| Item | Value |
|---|---|
| Application | Yulong Island Refining and Chemical Project, China (approx. $20 billion investment) |
| Type | Scotch-yoke pneumatic actuator, 90° rotation, spring-return |
| Safety rating | SIL 3 certified |
| Fail position | Fail-open (spring-return) |
| Spring-fail torque | 2.7 million in.lbs (approx. 305,000 N·m) |
| Available air supply | 50 psi (approx. 3.4 bar) |
| Stroke time | Below 31 seconds |
| Assembly dimensions | 13.5 m (44 ft) long × 2.6 m (8.5 ft) wide × 1.69 m (5.5 ft) high |
| Stroke volume | 164,800 in³ |
| Interlock functions | Topworx technology: partial stroke testing (PST) + emergency shutdown (ESD) |
The process loop served by this actuator demands both high mechanical load capability and fast response, while the available air pressure is only 50 psi. Delivering a 305,000 N·m-class fail-safe torque from roughly 3.4 bar of air is exactly what the scotch-yoke mechanism is for: cylinder force is converted to output-shaft torque through the yoke, with torque naturally amplified toward the end of travel — matching the seating demand of large valves. The spring-return design drives the valve to its safe position (fail-open in this case) on air failure.
Beyond raw force, the system must also "measure accurately and act fast": Topworx valve position technology supports partial stroke testing (PST) — proving the interlock function online with a small stroke without interrupting the process, a standard capability in SIL-rated loops — and full-stroke emergency shutdown (ESD) within 31 seconds.
"The mechanical requirements for this petrochemical facility pushed the boundaries of standard valve automation," said Aymen Ghorbal, President & CEO of Cowan Dynamics. "Engineering a Scotch-Yoke actuator over 13.5 meters long that can safely and reliably manage over 2.7 million inch-pounds of break torque is an immense physical challenge. Achieving this while maintaining strict SIL 3 safety compliance and sub 31-second stroke times is a testament to our team's mechanical expertise and our commitment to the global petrochemical market."
Source: Valve World, "Cowan Dynamics delivers 13.5 m Scotch-yoke actuator" (2026-10-09, by Valve World Publisher), original article. Need pneumatic actuators sized and supplied? Submit an RFQ.
An industry resource for electric & pneumatic actuators, dampers and heaters: brand manuals, sizing guides and maintenance know-how. Global brands in, China manufacturing out.
