An interesting demonstration of a ROTEX DRS high performance scotch yoke pneumatic actuator mounted on a large ball valve. Video shows actuator opening valve, closing valve, the valve position indicator, the hydraulic manual override and manual hydraulic pump. Good visual education for those who never saw a large valve and a large actuator.
A Central American power generation company needed 10" and 16", Class 900, triple-offset, critical service butterfly valves to operate flawlessly and quickly in the event of fire or loss of air supply. They chose ROTEX Controls double acting DRS Scotch-Yoke actuators with hydraulic overrides.
The actuator package also specified a (5) second or less close time, a fusable link for emergency close in the event of fire, a declutchable manual override, and ASME air receiver tanks for "fail mode" that would allow for (2) full operational cycles.
ROTEX Controls engineers also included a 3-way fusable link that supplied air to a pilot operated shuttle valve. If the system was exposed to fire, the fusible link will fail, venting the air feed to the pilot causing the shuttle valve to shift and energize the actuator.
The result was an actuator that closed the valve in under (3) seconds. Additionally, the automated packages were delivered on time and under budget!
16" & 10 " Triple Off-set Valves automated block valves. These are pneumatically operated valves with ASME air tanks for fail close operation on loss of electrical signal. Also included are manual hydraulic over-ride cylinders and spring loaded 3-way diverter valves with "fusible links.
After installation of valve in to pipe line, plant air is supplied to the tank inlet valve. A pipe from the tank outlet to the actuator with filter and regulator provides the actuator clean, regulated supply air.
All electrical connections for limit switch and solenoid valves are terminated in the limit switch housing.
Valve are supplied with small 3-way ball valves with fire-safe "fusible" links and spring loaded handles that will close the valve in the event of a fire.
The manual hydraulic over-ride is used in case of loss of air, or loss of electric. 6 foot and 15 foot hydraulic lines are used to supply the hydraulic cylinders power and must be connected of the valves will not function.
As designed, these valves open in under 5 seconds and close in 1.6 seconds, have the ability to be manually over ridden in the event of a loss of air or electric, and have fire-safe spring loaded links to close the valve in the event of a fire.
