Butterfly valves for air and gas 

VF and VFH butterfly valves are designed for regulation and control of air and gas flow.
Valves can be operated manually using a lever (to setup the high-fire rate of the burner) or automatically using a servomotor (modulating or staged control) or a solenoid actuator (two-stage control).
The setting can be monitored on a graduated scale, this allows  precise regulation ratios.
This type of device is suitable for air and gas adjustment in combustion processes, like industrial kilns, drying stoves, smelting and annealing furnaces.