Strana: 1|2|3|4|5|6

PNEUMATIC ACTUATOR - SPRING RETURN (FAIL SAFE)


Sizing example of spring return actuator:

Valve torque 60N.m plus 30% safety factor = 78N.m. Minimum operating pressure: 6bar(87psig). The spring return actuator selected is HTS-105-12. The HTS-105-12 has the following output torques:

1. air torque 0°(valve close) = 124N.m > 78N.m
2. air torque 90°(valve open) = 84N.m > 78N.m
3. spring torque 90゜(valve open) = 120N.m > 78N.m
4. spring torque 0°(valve close) = 80N.m > 78N.m



The operating principle of single acting spring return actuator

Air to port A forces the pistons outwards, causing the springs to compress. The pinion turns counter-clockwise while air is being exhausted through port B.	Loss of air pressure through port A allows the stored energy in the springs to force the pistons inwards. The pinion turns clockwise while air is being exhausted through port A.