View from the other side

How we arrived at smart actuators and what should be next?

This article, the third of our ‘View from the other side’ feature columns from our colleagues in the USA, is provided by Chris Warnett. Chris, a UK expatriate, is the President of CPLloyd Consulting Inc. Rochester NY, providing marketing and applications expertise for the valve and automation industry. Chris has over 38 years of engineering, sales and marketing experience in valves and automation. Reach him at chris@cplloydconsulting.com Tel 001 585 298 6239.

The majority of valve actuators used around the world on isolating valves fall into two main categories based on the power source used.

1) Electrically powered actuators that typically use 3 phase power to drive a motorized gear mechanism to operate any type of valve.

2) Fluid powered actuators that utilize pneumatic, hydraulic or electrohydraulic power on either a rack and pinion or a scotch yoke mechanism to move a quarter turn valve.

There are other types of valve actuator using other drive variations of motor or gear, but the vast majority of valve actuators fall under the two categories.

The typical fluid power actuator is a relatively simple mechanism. The tendency is for small actuators to use a rack and pinion mechanism and for larger actuators to use a scotch yoke. There are many manufacturers of rack and pinion actuators, so much so, that it is considered a commodity product rather than an engineered product. The scotch yoke device however is manufactured by fewer companies and their fundamental design is basically the same.

On smaller pneumatic actuators there is some standardization of the controls and positon feedback, for example under the NAMUR guidelines, but in general most pneumatic actuators have ‘bolt on’ control components manufactured by other parties. Different end users have their own preference for the type and manufacturer of these controls so there has been little in the way of standardized controls for the larger pneumatic actuators.

This means that the development of ‘smart’ components for pneumatic actuators resides with the manufacturers of the pneumatic controls rather than the actuator manufacturers. In the case of process control valves these are often the same manufacturer, but in the isolating actuator world the actuator prime mover manufacturer may not the same as the control device manufacturer. Even if they happen to be part of the same group of companies, they are not closely integrated in the design process.

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 separate a motor control room containing all the three phase motor starters, including the valve actuator motor controls.

Motor controls and position switches were later integrated in the electric actuator enclosure. This important change placed the actuator design, as an integrated package, under the control of the actuator manufacturer. This opened the possibility for them to incorporate significant advances in their actuator technology.

Later, robust explosion proof electrical enclosures allowed motor starters and switches to be incorporated in the electric valve actuator for field installation in hazardous oil, gas and chemical applications.

The development of superior sealing (often ‘O ring’) for the electrical enclosure allowed more sensitive electronic circuitry to be installed in the actuator. This 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 the non-intrusive configuration and commissioning capability of 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 the user to have a dialogue with the actuator made trouble shooting and record keeping fast and simple.

There are only a handful of large global manufacturers of heavy duty electric valve actuators and most of them now have products that offer these technologies. The non-intrusive feature, for example, has been available in the marketplace now for well over a two decades.

But has the pace of innovation has caught up with the requirements of the end use?

The sophistication of the diagnostic and maintenance tools may have outstripped the capability or desire of the majority of end users to take advantage of these technologies.

There has not been a real breakthrough development in the heavy duty valve actuator field for some time.

If end users are no longer demanding more technology than the existing manufactures currently supply, then how can manufacturers better satisfy their needs?

The competitive pressure on users of automated valves is as strong as ever. Manufacturers have to improve efficiency, productivity and safety continuously to remain competitive. The pressure on ROI is always there and this translates to downward pressure on equipment pricing. Despite the high level of sophistication in valve actuators, the price pressure is constant. Greater efficiencies in manufacture, 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 users maintain high plant efficiency and optimization.

Standardized reliable global products, with multiple manufacturing facilities and strong local service support, will be key competitive edge for the support of the end user decision makers.

This suggests that the design of the next generation of valve actuators should not only have the current level of technological features which users now expect, but should also be easy and quick to supply and support in the field.

This article first appeared online at the VALVE Magazine website (www.valvemagazine.com). Copyright © 2014 Valve Manufacturers Association (www.vma.org). All Rights Reserved.

Published: 25th February 2015