Actuators

Actuators are vital to the safe operation of nuclear plants and are used in numerous applications to control valves and ventilation dampers.  There are a variety of actuator types ranging from quarter-turn to linear and driven by electric motors, pneumatically, and hydraulically.  NLI offers products in each of these areas.

One of the advantages of NLI’s actuator offering is the companies we’ve selected to work with.  Because of NLI’s engineering expertise plus our ability to qualify equipment and provide quality assurance oversight, we went out and selected actuator manufacturers that were best-in-class.  While actuators are vital to nuclear plants, nuclear is certainly not the only industry to use them, and in fact, many industries are much more demanding.

The quarter-turn pneumatic actuator is the workhorse of the industry and most of the original equipment is now obsolete.  Newer models offer incremental improvements over flawed legacy designs.  NLI found an actuator company that took a radical approach to actuator design and built what can only be described as a better mousetrap.  QTRCO pneumatic quarter-turn actuators offer a balanced design and an all stainless steel construction.  And in a major departure from existing designs, they apply pressure from the outer ends of the balanced cylinders, so the body is not pressurized.  This eliminates the need for shaft seals – a common failure point with existing designs.  Additionally, the captured spring allows O-rings to be replaced without removing the actuator from the valve or damper.

NLI’s engineers worked with QTRCO to make their designs easier to qualify for nuclear applications.  Most models have just two easily changeable O-rings, and others use metal seal rings and are qualified for harsh environments.  NLI manufactures all QTRCO actuators sold to the nuclear industry.

Other NLI actuator partners like ATI and Beck are also well known in their respective areas of expertise.  ATI specializes in pneumatic, hydraulic, and electro-hydraulic actuators for rising stem valves.  Beck has been manufacturing actuators for 75 years and is renowned for their fine control modulated motors and sturdy gearboxes, which ensure reliability and extremely long lives.

 When requested by customers, NLI will qualify and supply other manufacturer’s actuator models.