High-precision actuation solution for multiport valves

Jon Lawson

AUMA actuators for multiport valves in hydrocarbon service support up to 16 ports with a combination of high speed and excellent precision, thanks to their variable speed motors. Positioning accuracy is better than 0.3° and lift plug valves are also supported, making the actuators suitable for the most challenging applications in this market.

Multiport valves require high positioning accuracy as they direct fluids from many different production inlets in turn to a single sampling system. AUMA’s SAVEx variable speed actuators achieve this through precise slow motion as the valve plug approaches its target port, virtually eliminating overrun. For most of the valve travel the motor runs at full speed, so cycle times remain short.

The SAVEx multi-turn actuators are rated for open-close duty and positioning duty (classes A and B) / (short-time duty S2-15 min). Special sizing for longer running times is available for the S2-30 min duty. Meanwhile, SARVEx multi-turn actuators are rated for modulating duty (class C) S4 - 25 %. Special versions for S4 - 50 % are also available.

Multiport valves featuring a lift plug design make actuation even more demanding because two different movements have to be coordinated: before the plug can rotate to the desired port it first has to be lifted from its seat. AUMA’s clever solution is to use two actuators in a master-slave configuration that appears to the DCS as a single actuator. The integral actuator controls handle the complete sequence of movements and the safety interlock that allows rotation to start only once the plug has been lifted into its ‘free’ position.