Pneumatically actuated butterfly valves are designed to allow / stop the flow of liquids, even chemically aggressive. The options permit automatic operations.
Electrically actuated butterfly valves are useful to stop the flow of fluids in part of a plant. Opened they do not induce pressure drop. These models in plastics are designed for aggressive liquids. Assistance with manual operating for maintenance or emergency operations (actuator power supply is switched off before a manual operating).