Butterfly valves are versatile and can be used at many different industrial applications, fluid, sizes, pressures, temperatures and connections at a relative low cost.
The development of this type of valve has been more recent than other ones. A major conviction on saving energy in the installations was an advantage for its introduction, due its head loss is small. At the beginning they were used in low pressure installations service, but technologic improvements, especially in the elastomer field let their extension to higher performances.
As of any quarter turn valve, the operation of the butterfly valve is easier understood. The closure member is a disc that turns only 90º; to be fully open or closed for quick operation.
As compared to Ball valve and Globe valve, friction of Butterfly shaft is much lesser. Hence, wear and tear is minimum. Another added advantage is a smaller torque is needed which equates to a smaller actuator. Net benefit, lower cost for actuator, be it is manual, hydraulic or electrical motorized.
Butterfly valves geometry is simple and compact, therefore, it is an economical valve category to manufacture in material usage and post mechanization.
Its reduced size makes its installation a breeze. Gate and globe valves are naturally heavier with slightly more complex geometry.
Butterfly valve’s head loss is smaller as flow goes aerodynamically around the disc when valve is full open. Although the head loss is higher than in spherical and gate valves, but because their flow zone are totally free from obstacles, it is clearly lower than in globe valves.
Butterfly valves also work seamlessly with any fluid, gas, liquid and also with solids in suspension. As a difference against Gate, Globe or Ball valves where cavities present which solid can be form to impair on the valve operation.
Pressure and temperature are one of the determining factors and correlated designing factors. At a constant pressure, rising temperature means a lower performance for the valve, since some materials have lower capacity. As of gate, globe and ball valves, the butterfly valve can be manufactured with metallic seats (metal-Metal contact) that allows high pressure-temperatures applications.