Valve Actuators for Corrosive and Hazardous Environments - Emerson Automation Experts

Valve Actuators for Corrosive and Hazardous Environments

For those non-mechanical engineers who have heard the phrase “rack and pinion” but are unfamiliar with the term, Wikipedia defines it:

"Rack and pinion animation". Licensed under Public domain via Wikimedia Commons

“Rack and pinion animation”. Licensed under Public domain via Wikimedia Commons

rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion.

A circular gear called “the pinion” engages teeth on a linear “gear” bar called “the rack”; rotational motion applied to the pinion causes the rack to move, thereby translating the rotational motion of the pinion into the linear motion of the rack.

John Hancill Strategic Marketing Director

John Hancill
Strategic Marketing Director

Emerson’s John Hancill, shared with me that the EL-O-Matic line of rack and pinion actuators, is typically used in on/off quarter-turn valves in harsh and hazardous environments. These actuators are designed for the automation of ball, butterfly, non-lubricated plug valves, and quarter-turn rotating mechanisms such as venting louvers.

These pneumatic actuators are intended for use in areas in which explosive atmospheres caused by mixtures of air and gases, vapors, mists or by air/dusts are likely to occur. Therefore it may be used in classified Zones 1, 2 (gases) and/or 21, 22 (dust).

To provide long-term corrosion protection, the new EL-O-Matic F-Series actuators are made of cast aluminum with low levels of copper and magnesium. Corrosion protection includes the powder coating on the actuator, high grade & hard anodized aluminum or stainless steel pinions that have passed a 500 hours accelerated salt spray test and stainless steel external parts.

Spring Return Actuator

Spring Return Actuator

Actuator torque is optimized with high-performance springs, designed to deliver a torque range suitable for a wide range of applications. Six separate spring sets help with proper sizing for all quarter-turn valve types with a wide range of supply pressures.

John pointed to some applications where these actuators have been applied. One food & beverage manufacturer developed problems with increasing torque requirements on their compact ball valves operating on a vessel’s heating jacket. The increasing torque led to actuator failures which impacted batch quality. The EL-O-Matic actuators provided the required torque and durability to become the standard for these types of applications.

He also shared a petrochemical plant application in which oil-derived waxes are produced. The bulk of the automated on/off valves throughout the facility were driven by the EL-O-Matic actuators.

In addition to these examples, corrosive and explosive environments found in offshore oil & gas production, onshore wellpads, refineries, and great applications for the EL-O-Matic F-Series actuators.

You can connect and interact with other valve automation experts in the Actuators track of the Emerson Exchange 365 community.

Posted Thursday, July 31st, 2014 under Actuator.


  1. Jonas Berge says:

    Also note that today you can get two-wire “intelligent” on-off valves by putting an on-off valve controller on on the rack and pinion actuator. This includes for example FieldQ and TopWorx ValveTop DXP. This enables the on-off valve to be integrated with Intelligent Device Management (IDM) software part of the Asset Management System (AMS) just like control valves and electric actuators / motor operated valves (MOV). That is, the on-off valve has diagnostics that can be viewed from a central location. It can also be configured through software. See explanation in this article:

    See further explanation of Intelligent Device Management here:

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