Getting Maximum Control Of Butterfly Valves

Update:06-03-2020
Summary:

Butterfly valves are a great (and less expensive) alter […]

Butterfly valves are a great (and less expensive) alternative to globe and other control valves in applications where 1-2% accuracy is acceptable. Process conditions will dictate whether a resilient seated or high performance butterfly valve should be selected.

A resilient seated butterfly valve is the most economical choice. If pressures and temperatures are not extreme, this type of valve should work just fine. If pressure and temperature exceed the limits of a resilient seat, a high performance butterfly valve is necessary.

Getting Maximum Control of Butterfly Valves

Other control valves have linear flowing characteristics. A butterfly valve’s design does not allow it to have linear flow characteristics (due to the shape of the disc and its relationship to the pipe), thus making it more difficult to control.

Consider adding instrumentation and a positioner to the valve to help gain more precise control of the valve. Also, make sure operating process conditions are ideal for proper control. Excessive temperatures and high velocities always need to be considered.

Though the butterfly valve isn’t the right choice for processes that require precise control, like mixing paints or food flavors, don’t throw it out of contention. It still has a place in the control valve category. We recommend looking to the butterfly valve first for control applications. It could mean the difference between $100 and $1,000.