Valve actuator torque calcs

[chettyc]

I am trying to calculate torque required to open a butterfly valve where the pressure is defined and the valve diameter is known. Is there such an equation or table for this?The fluid is water at 20degc and the upstream pressure is 10 bar anf the down stream is atmosphere.
Thanks in advance.

 

[atad]

I would suggest that you contact the valve manufacturer with your pressure, fluid and temperature parameters. The manufacturer will be able to give you the torque figures.

 

[owlscreech]

I agree with atad. These calculations involve calculating the torque required to overcome stem bearing friction, seating friction, packing friction and hydrostatic static/dynamic forces. While there are generic approaches, they are generally bounding. Therefore they will almost invariably end up with oversized operators. That means wasted dollars. Most valve manufacturers provide data and calculational procedures for seating/unseating torques for their product lines. These data are based on extensive testing and should be used as the primary approach to determine seating/unseating requirements.