Difference Between Ball Valve and Butterfly Valve

Ball valves and butterfly valves have a lot in common. Both are quarter-turn valves, which makes them easy to open. Both are quite popular because of their simple designs and low cost. Due to these factors, it might be hard to choose one that is best for you. In this article, you are going to know the difference between ball valve and butterfly valve to help you make an intelligent choice.

Ball Valve

The ball valve is characterized by a sphere-like disc encased in a globe-like valve body. This sphere-like disc is hollow. With a turn of the lever or handwheel by only 90 degrees, the disc opens to pass the media through, or closes to prevent the media from doing so. Ball valves are known to have low-pressure drops. 

Butterfly Valve 

The butterfly valve is a compact valve with a wafer-like disc that acts as a barrier when the disc is closed. Also, it only takes a quarter turn for this valve to open. Used for low-pressure and low-temperature flow systems, the butterfly valve is also lightweight and has a short face-to-face dimension. The working mechianism of butterfly valve is also different from the ball valve. The following are the main difference between the two valves.

Ball Valve vs. Butterfly Valve
 

                                                         

Application

Sealing performance affects how these valves are being used in services. Since ball valves have better sealing, they can be used in critical applications where issue on contamination is a priority. Also, ball valves are well-suited for gas applications, especially the low-pressure type. The ball valve has a wide variety of ANSI classes. It is also resistant to extremely cold temperatures such as those used in cryogenic industries.

On the other hand, butterfly valves are more cost-effective and do not occupy too much space in the plant. They are used in water services where there is a need to control the flow of media. Since the butterfly valve is more economical to build, it is used in large scale projects. 

Butterfly valve suppliers often follow the ANSI Class 150 rating. It means the valves can withstand pressures as high as 285 psi, with temperature ranging from -200F to 1000F.

Function

Ball valves are used only for isolation. Ball valves are known for their bubble-tight shutoff. Rarely would you see a ball valve used as a control valve because the soft resilient seat gets damaged easily in this condition. 

When the ball valve is open, there is very little interference from the valve parts, so the pressure drop is small. These valves are precise when used in high-pressure applications. There is no need for a pressure balancing scheme to equalize internal pressure.

Butterfly valves can act as isolation and control valves. But these don't provide bubble-tight shutoff. For the valve to be a great throttling valve, it needs the media to move slowly to avoid friction.

Also, there is a substantial pressure drop in the linear pressure when the butterfly valve is open. The medium is always in contact with the disc as it flows, resulting in a change in pressure. 

For larger butterfly valves, a bypass valve may be installed to compensate for the balance of pressure. Additionally, larger butterfly valves may need pneumatic or electronic actuation as these valves are difficult to manually open.

Structure

The ball valve has a hollow sphere-like disc inside the valve body. The butterfly valve has a thin disc with a relatively thin body.

Conclusion

Ball valves and butterfly valves are inexpensive, practical and durable. Which one to pick depends on the nature of your projects. Butterfly valves in America is also in good quality and you can also consider some nice manufacturers. Contact a highly dependable valve manufacturer for assistance when choosing the right kind of valve.