What might be around the next curve for smart actuators? Before suggesting some answers to that question, let’s first discuss how today’s actuators evolved.
Most valve actuators used for isolating valves fall into two main categories, based on the power source used:
- Electrically powered actuators: typically use three-phase power to drive a motorized gear mechanism to operate any type of valve.
- Fluid-powered actuators: use pneumatic, hydraulic or electrohydraulic power on either a rack and pinion or a scotch yoke mechanism for moving a quarter-turn valve.
Other types of valve actuators that use drive variations of the motor or gear exist, but most fall under those two categories.
The fluid power actuator is a relatively simple mechanism. Typically, small actuators use a rack and pinion mechanism while larger actuators use a scotch yoke. Because so many manufacturers of rack and pinion actuators exist, such actuators are considered a commodity product rather than an engineered product. Fewer manufacturers make the scotch yoke device, and the fundamental design is largely the same, though some variations do exist.
On smaller pneumatic actuators, some standardization of the controls and position feedback exists under guidelines such as those from NAMUR. But in general, most pneumatic actuators have “bolt on” control components manufactured by other parties. End users have their own preferences for type and manufacturer of these controls so very few standardized controls have been created for the larger pneumatic actuators.
This means that manufacturers of the pneumatic controls have developed the “smart” components for pneumatic actuators rather than the actuator manufacturers. In the case of process control valves, the controls and smart component makers are often the same manufacturer. But in the isolating actuator world, the manufacturer of the actuator’s prime mover may not the same as the control device manufacturer. Even if they are part of the same group of companies, it’s not likely the two parties are closely integrated in the design process.
How Electric Actuators Evolved
Electric actuators have developed in a different way.
Initially, the valve actuator was a motorized gearbox with torque limiting switches and a separate motor control. Power plants, for example, used a separate motor control room containing all three-phase motor starters, including the valve actuator motor controls.
Motor controls and position switches were later integrated into the electric actuator enclosure, an important change that placed the actuator design, as an integrated package, under the control of the actuator manufacturer. This opened the possibility for incorporating significant advances in actuator technology.
Later, robust, explosion-proof electrical enclosures allowed motor starters and switches to be incorporated into the electric valve actuator for field installation in hazardous oil, gas and chemical applications.
The development of superior sealing (often an “O ring”) for the electrical enclosure allowed more sensitive electronic circuitry to be installed in the actuator, which allowed greater monitoring and control options to improve controllability and safety.
The rapid development and adoption of electronic control and communications systems led to the innovation of a non-intrusive configuration and commissioning capability for the automated valve. This prevented the ingress of dirt and moisture into the actuator enclosure during field start up, one of the most vulnerable times for an automated valve.
Wireless technology then made the non-intrusive setup even more versatile and easy to use. The ability for a user to conduct dialogue with the actuator made trouble shooting and record keeping fast and simple.
Where We’re Headed
Only a handful of large global manufacturers make heavy-duty electric valve actuators, and most have products that offer the newer technologies. The non-intrusive feature, for example, has been available in the marketplace for more than two decades.
But has the pace of innovation caught up with the requirements of the end users?
The sophistication of diagnostic and maintenance tools may have outstripped the capability or the desire most end users have to take advantage of these newer technologies.
Meanwhile, a real breakthrough development in the heavy-duty valve actuator field has not occurred for some time.
If end users no longer demand more technology than the existing manufacturers currently supply, how then can manufacturers better satisfy their needs?
The competitive pressure on users of automated valves is as strong as ever. Likewise, to remain competitive, manufacturers must continually improve efficiency, productivity and safety. The pressure for better returns on investment is always present, which translates to downward pressure on equipment pricing. Despite the high level of sophistication in valve actuation, this price pressure is constant. Greater efficiencies in manufacturing, supply and support may be the next area of focus for the valve actuator companies.
This may result in a new form of actuator design that allows faster fulfillment to global users with service and support infrastructure that can help those users maintain high plant efficiency and optimization.
Standardized, reliable global products with multiple manufacturing facilities and strong local service support will be a key competitive advantage to support end-user decision makers.
This suggests that design of the next generation of valve actuators will have both the current level of available technological features users now expect—and also be easy and quick to supply and support in the field.