Total capability in valve actuation

IMI STI is a world-leading manufacturer of complete actuation systems customised to meet the requirements of the world’s most demanding applications and processes.



Vibrant red actuators await packaging and shipping at IMI STI facility, ready to power valves worldwide with their reliable precision.

World leading solutions

Founded in 1962 and with an installed base of 220,000 actuators, we provide a diverse range of actuation solutions for severe service applications in the power, oil and gas and liquid natural gas industries. Our high-quality, reliable solutions include a range of linear and quarter turn valve actuators (pneumatic, hydraulic and electro-hydraulic), traditional and smart positioners as well as a complete range of accessories.

Impressive combined cycle power plant, underscoring the significance of gate valves in controlling the movement of steam and gases.

Advanced actuation technology for critical applications

IMI STI actuation specialists in the North Sea, expertise in controlling movement and operation.


We design and manufacture highly reliable, fast-stroking actuators that are widely recognised for their excellent performance in the highly demanding power sector. You will find our actuation solutions on turbine bypass systems, steam damper heating, traditional and nuclear boiler level control, pump recirculation, emergency shutdown, line isolation and dampers for fans.

Offshore platforms extract and process oil and gas from offshore reserves. They require technical expertise and hard work in drilling, production, and maintenance. The operation process involves manual and auto functions controlled from a central control room

Oil and gas

Smaller and increasingly more remote oil and gas resources have led to the growing demand for equipment able to operate effectively in harsher process conditions. We design robust solutions that improve safety and plant performance while meeting those tough environmental standards, providing best-in-class anti-surge, choke valves, gas-to-flare and dampers for fans.

The spherical gas reservoir relies on high-performance actuators to control gas flow, enabling efficient storage and processing of LPG/LNG at the refinery.

Liquid natural gas

The use of Liquid Natural Gas has grown exponentially in recent years, and we play a key role in most aspects of the process including gas production, transmission, liquefication, shipping, regasification, storage and distribution. More than 90% of the compressor anti-surge valves in operation in LNG plants globally have been fitted with our high-quality actuation control solutions.

Key Technologies

Linear actuators

Valve piston and damper actuators are one of our key technology solutions and we develop and manufacture them for use on flow control devices such as dampers, louvers, butterfly and ball valves.

Key Technologies

Quarter turn actuators

To cover all on/off valve and modulating control duties, we have developed our innovative RT series. This complete range of pneumatic and hydraulic quarter-turn actuators is used widely across a number of industries and is renowned for its reliability.

Key Technologies

Control drive actuator

Used widely in power stations, the steel industry, petrochemical plants and in remote desert regions across the world our pneumatic actuator system ensures first-class, continuous operation in the harshest of environments.

Key Technologies


We offer a wide range of positioners including pneumatic, electro-pneumatic, smart (very high flow rate) or ‘traditional type’.

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Aftersales support

We supply actuators and accessories for use in some of the world’s most demanding applications and provide best-in-class after-sales support to ensure they remain at peak performance. Our team of expert engineers is available around the clock to provide onsite support, troubleshooting and maintenance services along with express delivery of spare Fast delivery of spare parts, 24-hour shipment service.

Case Study

Anti-Surge valve solution at oil rig in the Indian Ocean

Case Study

New layout design for HIPPS installation

IMI Critical’s Valve Doctors created a cost-efficient new layout design for a HIPPS installation without compromising on material quality.