AUMA TIGRON Fail Safe Spring-Return Electric Actuator

AUMA TIGRON Fail Safe spring-return electric actuator

The AUMA TIGRON Fail Safe is a part-turn electric actuator that combines a mechanical return spring with a scotch yoke mechanism. It targets large valves that must close or open reliably when mains power is lost, without compressed air or hydraulic systems. The TIGRON Fail Safe covers a torque range of 2,000 Nm to 60,000 Nm and a swing angle of 90 degrees. Seven Star LLC supplies AUMA products in Oman and the GCC as an independent supplier; this page sets out what the TIGRON Fail Safe is, how it is built and what an enquiry should contain.

In the safe direction the stored spring energy moves the valve to its fail-safe position. In normal service the electric drive moves the valve and re-compresses the spring, so the device is an intelligent electric actuator with a purely mechanical safety function.

TIGRON Fail Safe technical data

Operating principle of the TIGRON Fail Safe

A scotch yoke converts the linear force of the spring and of the drive into a rotary torque at the valve shaft. The yoke arrangement is known for delivering high torque at the ends of the stroke, which is exactly where ball, plug and butterfly valves need it most for unseating and tight shut-off. The mechanical spring provides the emergency energy, therefore the fail-safe action does not rely on a battery, a hydraulic accumulator or an air receiver.

The manufacturer highlights three attributes: the actuator is safe, because the spring supplies energy at power failure; low-maintenance, because the components wear little and no pneumatic or hydraulic system is required; and intelligent, because TIGRON communicates with the DCS including position feedback, and its diagnostic functions help keep availability high.

Where the TIGRON Fail Safe fits in a plant

Typical choices are large pipeline and header isolation valves, emergency shutdown valves on tank and loading lines and cooling water or seawater valves where a fail-closed or fail-open position is required. Heavy valves above several thousand newton metres are often hard to serve with pneumatic spring-return actuators because the cylinders and air systems become very large; the TIGRON Fail Safe offers an electric alternative up to 60,000 Nm. For lower-torque SIL applications see the TIGRON TR-M SIL and the FQM/FQMEx SIL unit.

TIGRON Fail Safe selection checklist

• Valve torque for the full stroke, including breakaway and seating values for both directions
• Required fail-safe direction: closing or opening on loss of power
• Required operating time for the 90 degree stroke, within the stated 1 to 60 s range
• Ambient temperature extremes and whether the actuator will be outdoors in direct sun
• Valve flange and shaft dimensions and the mounting position
• Control interface and feedback requirements for the DCS
• Whether a safety-integrity requirement applies to the complete valve assembly

Installation and maintenance of the TIGRON Fail Safe

Because the unit stores spring energy, mounting, dismounting and any work on the spring section must follow the manufacturer instructions and be carried out by trained personnel. Lifting points, the mass of the assembly and the support of the valve must be checked in advance, as 60,000 Nm units are heavy. During commissioning, end positions and torque limits are set through the electronics, and the emergency stroke should be verified by an actual loss-of-power test. Since the components show low wear and no air or oil system is present, routine maintenance is mainly visual inspection, verification of the emergency stroke time and review of the diagnostic data recorded by the actuator.

Applications in Oman and the GCC

In the Gulf, spring-return electric actuators are attractive where instrument air quality is poor, dust and humidity load is high or remote sites lack compressed air. Oil and gas export lines, gas plants, power stations with cooling water systems and desalination plants with large seawater and brine valves are all natural candidates. The wide ambient range, from -65 °C to +75 °C, covers desert heat as well as colder export locations, and the IP68 enclosure suits wash-down, flooding and sand exposure.

Comparing TIGRON Fail Safe with other fail-safe options

Information to send with an RFQ

• Part number: TIGRON Fail Safe and required torque
• Valve type, diameter, pressure class and maximum differential pressure
• Fail-safe direction and required closing or opening time
• Supply voltage, frequency and control interface
• Site ambient range and hazardous-area requirement if any
• Quantity and delivery location

Site conditions in Oman for the TIGRON Fail Safe

Valves and their accessories in Oman work in demanding conditions: high ambient temperatures, direct sun on outdoor pipe racks, dust, and corrosive coastal air at many oil, gas and water sites. When you specify the TIGRON Fail Safe, confirm the pressure and temperature ratings, body and trim materials and any sour-service or hazardous-area requirements against the actual line data, and check that seals and soft parts suit the process medium and the full temperature range.

For reliable operation, plan access for maintenance, define which spare parts are kept on site, and record the configuration of each installed TIGRON Fail Safe. Sending the complete process data sheet with your RFQ allows the selection to be checked before the order is placed.

Documents and quotation

Send the part number TIGRON Fail Safe, the application and the quantity, and Seven Star LLC will confirm which official documents are available for your configuration. Please do not rely on a general description alone: the order data, wiring diagram number and explosion-protection marking of the delivered unit are what count for engineering and commissioning.

Seven Star LLC is an independent supplier in Muscat serving customers across Oman and the GCC. Quotations are prepared against your enquiry data and are confirmed individually.