25
Design and Function
Function
Function
Spring-to-close actuator (Z)
The valve is closed in the non-actuated position.
In the standard version, the control valve is supplied with a spring-to-close actuator –
spring closed in the non-actuated position –, i.e.:
If the input signal at the positioner increases, the control valve opens.
Spring-to-open actuator (A)
The valve is open in the non-actuated position.
If the input signal at the positioner increases, the control valve closes.
