Explosion-Proof Electric Actuator for Valve — 1/4 Turn, ISO5211, IP66/IP68, ATEX / IECEx / CSA, 35 to 1500 NM

The explosion-proof electric actuator for valves from Cematic is the standard device for automating ball and butterfly valves in industrial areas classified as hazardous. Its flameproof and combustible dust-proof enclosure also ensures that any internal ignition is contained within the actuator body.

Therefore, it cannot trigger an explosion in the external atmosphere. It is also certified under ATEX, IECEx, and CSA, complying with international standards for Zones 1, 2, 21, and 22 with Group IIA/IIB gases and Group IIIC dusts. It is also available with torques from 35 to 1500 NM and in On-Off or Modulating modes.

Unlike the standard electric actuator in the OM range, this model does not include spring return. Therefore, the valve's position in the event of a power loss remains in the last commanded state.

However, when the process requires automatic closure upon power failure, the assembly with a fail-safe spring return actuator must be specified. See explosion-proof fail-safe actuator →

Why an explosion-proof actuator — and when it is necessary

A standard electric actuator is not suitable for classified areas because its internal electrical components can produce sparks or heat above the ignition temperature of the environment. The explosion-proof electric actuator, however, is built with specific protective measures for classified areas:

• Flameproof enclosure (Ex db): The actuator body is designed to contain any internal ignition. The housing joints and threads are also machined to specific tolerances that prevent flame propagation to the outside. Therefore, even if an internal spark occurs, the explosion is contained within the actuator body.
• Protection against combustible dust (Ex tb): The IP66/IP68 enclosure also prevents combustible dust from coming into contact with internal electrical components. The maximum surface temperature (T130°C) is also below the ignition temperature of most common combustible dusts.
• Self-locking gear system: The gear system also maintains the valve position without continuous current, resulting in zero standby consumption. Therefore, there is zero energy consumption in standby and no heat generated by friction in the transmission system.

Classified areas where this actuator applies

The ATEX/IECEx certification of this actuator enables it for the following zones, according to the installation's risk level:

• Zone 1 — occasional presence of explosive gases: Areas where an explosive gas atmosphere may be occasionally present during normal operation. Therefore, it is the most common zone in refining, gas plants, and petrochemical processing. Thus, the actuator meets the requirements for Zone 1 with Group IIB gases.
• Zone 2 — unlikely presence of explosive gases: Areas where an explosive atmosphere is unlikely under normal conditions. However, it may occur under abnormal conditions or during maintenance. The actuator also meets the requirements for Zone 2 without additional restrictions.
• Zone 21 and Zone 22 — combustible dusts: Areas with the presence of suspended combustible dusts. The Ex tb IIIC T130°C Db certification also covers Group IIIC dusts. Therefore, it is the correct actuator for metal dust, coal, flour, and sugar plants.

On-Off vs. Modulating in hazardous areas

This actuator is also available in two control modes depending on the process requirements in the classified area:

• On-Off: The actuator operates in two positions — fully open or fully closed — by an electrical signal from the control system. Therefore, it is the standard option in isolation, shut-off, and diversion systems in hazardous areas. The control signal is digital, so no signal converters are required between the safe area and the classified zone.
• Modulating: The actuator positions the valve proportionally to the 4-20 mA signal. Consequently, it is the correct option for PID control loops within classified areas. It also includes 4-20 mA position feedback for verification from the control system.

Torque selection

The actuator torque must also be greater than the operating torque of the valve at maximum working pressure. The available range covers everything from small ball valves to large diameter butterfly valves. The available range is described below:

• OME-1 — 35 NM: For ball and butterfly valves in diameters from 1/2" to 2". It also includes a manual override lever. Therefore, it is the entry torque of the Ex-Proof range for small diameter installations.
• OME-A / OME-AM — 50 NM: For valves in diameters from 2" to 3". The OME-A does not include manual override; the OME-AM, however, includes an integrated lever. It is also the most compact torque in the range for intermediate diameters.
• OME-2 / OME-3 — 90 to 150 NM: For valves with diameters from 3" to 6" or valves that require more torque. They also include a manual override handwheel and adjustable mechanical stops.
• OME-4 to OME-6 — 400 to 650 NM: For 6" to 12" butterfly valves or valves at high differential pressure. They are also the standard torques in large diameter industrial process lines.
• OME-7 / OME-8 — 1000 to 1500 NM: For the highest torque applications in large diameter or high pressure valves. Therefore, they cover the most demanding industrial services in the Ex-Proof range.

Technical specifications

Hazardous area certifications

Applications of the explosion-proof electric actuator

Petrochemical and Refining Industry

The explosion-proof electric actuator is the standard component for valve automation in refining and petrochemical process plants. The ATEX/IECEx/CSA certifications also enable it for the most common classified areas in this sector.

Therefore, no additional safety barriers are required in the control signal. Thus, it is the correct actuator in hydrocarbon shut-off and regulation systems in Zones 1 and 2.

Natural Gas and LPG Plants

In natural gas, LPG, and biogas installations, this actuator also controls valves in potentially explosive atmospheres with full regulatory safety. Its certification for Group IIB gases also covers natural gas, propane, and the vapors of the most common solvents in these installations.

Consequently, it is the reference actuator in gas compression, distribution, and storage stations.

Chemical Industry with Flammable Fluids

In chemical synthesis plants, storage and handling of solvents and flammable products, this actuator allows valve automation in classified areas. The Modulating version is also the correct option in flow control loops where continuous regulation is a requirement.

Therefore, it is the most versatile explosion-proof actuator for the chemical industry. Therefore, it is the most versatile explosion-proof actuator for the chemical industry.

Mining and Processes with Combustible Dusts

In mineral processing plants and the production of flour, sugar, and other combustible dusts, the Ex tb IIIC T130°C Db certification also enables this actuator for Zones 21 and 22. Its maximum surface temperature of 130°C is also below the ignition temperature of Group IIIC dusts.

Consequently, it is the standard actuator in installations where protection against combustible dusts is a regulatory requirement of the plant.

Power and Cogeneration Plants

In power generation plants using fossil fuels or biomass, this actuator also automates valves in areas with the presence of flammable vapors or gases. Its range up to 1500 NM also covers large diameter valves in power process lines.

Therefore, it is suitable for steam, boiler water, and fuel line control in cogeneration plants with classified areas.

For the complete range of explosion-proof actuators, see Ex-Proof actuators collection →

Technical Data Sheet - OME 

Data Sheet - OME

User Manual - OME