ATI Quarter-Turn Gas-Over-Oil Actuator

Performance Highlights




The ATI Quarter-Turn Gas-Over-Oil valve actuator is designed to operate using direct pipeline gas with pressures up to 1500 psi, providing torque outputs over 1 million inch-pounds. The design utilizes a proven canted scotch yoke actuator with dual oil tanks. With the cylinder always immersed in oil, the Gas-Over-Oil actuator provides maintenance free, long cycle-life actuation. The control modules can be used with the actuator to implement various valve control strategies.

ATI Quarter-Turn Gas-Over-Oil Actuator Performance Highlights

Single Cylinder-Dual Oil Tanks

Utilizing a single cylinder of varying size with ASME rated oil tanks mounted directly on the actuator body, the Gas-Over-Oil actuator uses the hi-pressure gas direct from the pipeline to pressure the hydraulic fluid in the tanks into the cylinders at up to 1500 psi. The proven poppet valve is used to direct the power gas to the appropriate oil tank. A hydraulic hand pump is installed in the control circuit between the oil tanks and the cylinders to provide smooth, efficient manual operation. When pipeline pressure is not available, the manual hand pump can be used to safely and reliably open and close the valve at its maximum torque requirement. Independently adjustable opening and closing speed controls are built into the manual hand pump module and are easily adjusted in the field without the need for special tools. Utilizing the pipeline gas for both the pilot gas and power media makes the Gas-Over-Oil actuator system independent of regulator and other power media failure.

Canted Scotch Yoke Design

The canted sctoch yoke mechanism uses small cylinder which provide high breakaway torque at the beginning stroke and reduce costs and gas consumption. All Gas-Over-Oil actuators utilize Teflon impregnated, sintered bronze bushings on a heavily chrome-plated guide bar to absorb any side loads guaranteeing smooth operation and longer cycle life.

Linear Travel Stops

The externally adjustable travel stops are on center with the piston rod, eliminating side loading to the scotch yoke. Located at either end of the actuator, these travel stops provide precise adjustment. Both the open and close travel stops are independently adjustable.

Electroless Nickel Plated Cylinders

The hydraulic cylinder walls are electroless nickel plated and precision honed to ensure long lasting, trouble free service. All pistons are furnished with a teflon impregnated graphite guide ring (wear band) that eliminates any possible metal to metal contact. The piston and rod seals are made of Teflon rings preloaded by an O-ring suitable for the most severe working conditions.


ATI Quarter-Turn Gas-Over-Oil Actuators are used in the following industries. Click below to learn more.

Our Client


I have to say, we looked at the valves and the actuators this afternoon and they are very well packaged and presented. I want to thank ATI for the attention this order has clearly received & I plan to pursue similar solutions in the future with you guys.


In all of the readiness reviews that I have conducted, ATI is by far the most well-prepared. The organization has built a solid foundation, and is off to a healthy start to the new [ISO 9001:2015] standard; ATI has clearly taken a serious approach to addressing the risks of its business and handling mitigation in a controlled manner.

Tom R., , Independent Auditing Agency

ATI linear actuators on 6-inch and 8-inch gate valves have worked flawlessly since put in Y-grade liquid service in 1994.

George Ford, Engineer, Enterprise Products

I was impressed and quite thankful for ATI’s commitment to get the job done on time and with a high level of quality.

Konrad M. Fontenot, Engineering Section Group Lead, Exxonmobil Beaumont

ATI has been supportive when we have had questions and their product has worked well for us. If the application came up again where we had the choice of using the ATI actuators, I would recommend getting them.


All of our switching valves for our mole sieve beds are orbit valves fitted with ATI actuators. These have been in service for ~8 months now and have had no issues.


ATI was very supportive during this project with helping us when we had to retrofit the actuators to the valves during a quick series of valve replacements.


We have 14 of your actuators at this facility, with a clean rack record for over a decade.

Maintenance Team Member, Industrial Gas Supplier

I really appreciate the commitment to deliver the needed products on a very short schedule.

Instrument Engineering Section Member, Gulf Coast Refinery

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