Rotork GTE Range Rack and Pinion Pneumatic Valve Actuator

Rotork GTE Range cost-efficient rack and pinion actuators and how they differ from the GT

The Rotork GTE Range is a pneumatic rack and pinion actuator series optimised for 90 degree part-turn valves. Where the GT Range offers 21 body sizes, optional rotation angles up to 240 degrees and a very wide material and temperature menu, the GTE is positioned by Rotork as a cost-efficient solution for general valve automation: fixed 90 degree drive, fourteen body sizes from 050 to 300, a torque capability of 2 to 6,300 Nm and a simple, compact design. It is built for the large population of ball, butterfly and plug valves that need a dependable on/off or fail-safe drive without special features.

The model code is easy to read from the torque chart. The letters GTEA are followed by the size, for example GTEA110, and then DA for double-acting or FC plus a spring count for spring-return fail-close, such as GTEA110FC08. Spring-return units use cartridges in the same body, which makes it possible to convert a double-acting actuator into a spring-return one in the field by adding springs, or the reverse by removing them.

Technical specifications of the GTE Range

On the GTEA300 double-acting unit the brochure limits operating pressure to 6.7 bar, and to 7 bar for spring-return, so check the torque chart footnotes for the largest size.

How the GTE Range produces torque

Air applied between two pistons drives them apart or together, and the racks on the pistons rotate a central pinion that turns the valve shaft. In a double-acting actuator, air is switched from one chamber to the other to drive the valve open or closed. In a spring-return actuator, spring cartridges push the pistons back when air is exhausted, producing a defined fail position. The brochure torque chart gives, for each spring-return model, the spring torque at 0 and 90 degrees and the air-assisted torque at each supply pressure, so the torque available at both ends of the stroke can be checked against the valve.

Double-acting output scales roughly with pressure. For instance, the brochure chart gives 30 Nm for a GTEA050 at 8 bar, 266.9 Nm for a GTEA110, 1,073 Nm for a GTEA160 and 4,607 Nm for a GTEA270. Sizing should include a safety factor above the valve’s maximum torque and take account of minimum supply pressure at the actuator rather than at the compressor.

Where the GTE Range fits and related Rotork actuators

Use the GTE for general purpose quarter-turn automation where 90 degree rotation, anodised aluminium construction and standard temperature options meet the requirement. If you need 120, 180 or 240 degree rotation, high temperature to +160 °C, or special coatings, the GT Range is the more flexible choice. For stainless steel construction in marine, offshore, pharmaceutical or sanitary service, use the GTS Range. Our site also lists the Rotork CP compact pneumatic actuator, the GP/GH scotch yoke range for high torque and the IQT3 electric part-turn actuator, which serve different supply and torque needs.

Selection and ordering checklist for the GTE Range

• Valve torque at break, run and seat, with a safety factor.
• Double-acting or spring-return, and the fail direction.
• Minimum supply pressure at the actuator, up to the 8 bar rating.
• Ambient temperature, and whether the enhanced low-temperature seal set is needed.
• ISO 5211 flange size and shaft drive, or a mounting kit.
• Accessories such as NAMUR solenoid, limit switches or positioner, and manual override.
• Corrosion protection suited to coastal or chemical sites.

Installation, commissioning and maintenance

Fit the actuator on the valve using the specified bracket or mounting kit, with the valve and the actuator in the same position before coupling. Connect air through the NAMUR port or an accessory manifold, and use dry, filtered air. Set the travel stops to the valve seat positions; the brochure allows five degrees of adjustment at each end. Cycle the valve several times, observe the position indicator, and record the supply pressure and stroke time for later comparison.

Because spring-return units are loaded, never remove end caps from an actuator that still contains springs without following the manual. Typical service involves checking for air leaks at the end caps and pinion, replacing O-rings and bearings with a service kit and relubricating as needed. A de-clutchable manual override can be added where the valve must be operated on loss of air.

Typical applications in Oman and the GCC

GTE-class actuators are used on cooling-water and seawater butterfly valves, utility and instrument air isolation, fuel and lube skids, chemical dosing and water treatment lines at Gulf oil and gas, power and desalination plants. With ambient temperatures that regularly pass 50 °C in the sun, check the maximum rating of the seals and keep solenoids and positioners shaded. Dust and humidity call for sealed accessories, and corrosive coastal air may justify protective coatings or a move to the GTS stainless range.

GTE sizes at a glance

Information to send with an RFQ for the GTE Range

• Valve type, size, class and torque curve, with ISO 5211 flange.
• Double-acting or spring-return with fail direction.
• Air pressure, temperature range and area classification.
• Accessory package and control signals.
• Quantity and timing.

Documents and quotation

The Rotork GTE Range brochure is attached on this page. Send the details above and we will confirm availability and prepare a quotation for the GTE Range in Oman and the GCC. Seven Star LLC is an independent supplier in Muscat.