The AUMA fail-safe actuator
Incorporating a patent pending constant force spring motor, the new AUMA fail safe unit mechanically provides the required torque in the event of an emergency, this product is designed for hazardous areas (like in the O&G indusry) where the actuator must open and close the valves even if the power supply is not avalable. While conventional springs lose 80% of their torque across valve travel, the AUMA solution provides virtually constant torque. Additionally, an overriding gear arrangement ensures that the spring does not move during standard operation. Both these factors contribute to enabling selection of significantly smaller actuator solutions. Premature spring fatigue and excessive torques at the valve are also avoided.
A further special feature of the AUMA FQM innovation is variable running speed during fail safe operation. The soft end position approach of the valve is achieved by reduced speed. This also avoids pressure peaks within the pipeline and preserves the valve.
The AUMA fail safe unit is particularly suited to automation of butterfly valves and ball valves at an angle of up to 90°. The fail safe unit meets the requirements of safety-related applications up to SIL 2/SIL 3 and is virtually maintenance-free. An explosion-proof version is also available.
