Maximum Pressure on Butterfly Valves

Butterfly valves with more than 8" diameters at applications of more than 100 PSI are wisely to be changed to Spherical MOV (motor operated Valve) or ROV (Remote operated valve), In Zakum Develpment Filed in Abu Dhabi U.A.E All valves was changed in 1986 from butterfly to spherical valves with either electrical motor operated or Pnumatic Air operated. Even if some one tell where is it used it will not be wise to use..

Dr. Awad El Sayed

One of the problems you will encounter with large diameter butterflys is the dreaded cavitation, @ small openings, the thing will shake it self apart ! Use ball, spool or sleeve valves instead.

The butterfly valve are used on-off, I know a case when at low pressure (60psi) a valve of 12" fail the disc because theyt used to regulated a water flow. I like to know if anybody have any experince at hydroelectric plants.??

Few years ago I was working in a hydroelectric power plant with a nominal head of 150 meters and the turbine inlet valve is a butterfly valve of 1.80 meters in diameter.

This valve has a by-pass line to equalise the pressure on both sides of the disc prior the openning but, eventually, in case of failure of this by-pass,the valve is put in "crack openning" position (around 10 %open) in order to achieve the pressure equalisation.

This plant has been in operation for around two decades, the "crack openning" operation has been achieved several times and, no problems in this valve have occurred.

I recive information about over 260 m of water pressure the admision valve have to be spheric, Any body cant confirmed that pressure??