Solenoid actuator for butterfly valves

Solenoid actuators are designed to operate VF and VFH butterfly valves.
When the coil is not energized the inner spring pushes down the plunger and, by means of a gear mating, shifts the connected valve to the minimum opening position.
When the coil is powered the plunger moves up fast (SR) or slowly (SL-ST), shifting the valve to the maximum opening position.
This type of device, connected to VF and VFH butterfly valves,
is used in two-stage control of gas and air flow in combustion processes.