New manual actuator for control valves
10 April 2019
Manual control valves are often used in pilot and production plants. The most common use of manually operated valves is clearly as a shut-off device.
On some occasions however, manually operated valves are also used as a fixed control valve, which can be a cost effective alternative to automated solutions in continuous processes, where changes in the valve setting never or very rarely occur.
Valves with the new manual actuator can be passively integrated into an automation concept, so it is possible to provide a manual control valve with an analogue position feedback and/or digital limit switches. It is also possible to replace the actuator at a later date for an automated solution if desired. As the manual valve is compatible with the standard valve design, the valve can remain in the system during conversion.
In previous designs of such valves, the plug typically is ‘screwed’ in a rotational movement in the direction of the seat. At micro flow rates, this can damage the seat plug set and it is for this reason that manual control valves could not be used with small Cv values in the past. It was also difficult to seal manual control valves with a metallic bellows. The new manual actuator prevents this rotation. With the new manual control valve, the valve is now raised and lowered in a pure linear motion.