Answer / instru

Rotary valves like Ball, butterfly valves are called as
high recovery valves. High recovery means less pressure drop
ofcourse compare to Globe valves. The biggest problem with
high recovery valves is that they are prone to Cavitation.
In case of Globe valves the path is quite torturous and
hence less prone to cavitation. In case of ball valves flow
is starigh through the ball. Cavitation occurs when pressure
at the vena contract drops below the liquid vapour presure.
In case of ball valves the vena contracta pressure and inlet
pressure have marginal difference ( thats why high
recovery). When inlet pressure and vena contract pressure
are clsoe to each other valve is definetely to cavitate .
Hence Ball valves are not used in applications where
cavitation is likely to occur.

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