What is the difference between spring return and double acting actuators?

Spring-return (single) actuators supply power/pressure to only one side of a piston, the spring powers the alternate side moving the valve to open or close position.

In contrast, the double-acting actuator uses piston element to operate the valve therefore both chambers require pressurization.

单作用执行机构,有故障位置,双作用执行机构必须通过储气罐,才能实现故障位置,带口径较大的执行机构。

Single acting actuators with fault position, double acting actuators must pass through a storage tank in order to achieve a fault position with a larger diameter.