Is a butterfly valve only considered a type of flow control valve if it is

Every type of valve can be generally considered to be a flow control
device. Most types of valves, gate, globe, ball, B’fy can

be manually
set anywhere from full open to fully closed and can be set to any
partially open position.

The term control valve generally refers to valves, including butterfly


types that are automatically regulated to modulate a rate of flow
according to a control signal to the valve actuating device.

Sometimes
the signal is from a remote sensing element such as the temperature
sensor controlling a refrigeration expansion

valve. Sometime the signal
is from within the actuating device itself as in a water pressure
regulator in your home city water

supply.

The signal itself can be modulating , as above or it can be on/off such
as an emergency shutdown valve on a steam

turbine or the on/off valve
on your washing machine.
From the original1checkvalve
.