Selection of valves

Butterfly valves regulate and shut off flow by rotating a butterfly plate within the pipe diameter. Since the drive mechanism is located inside the pipe, there is high fluid resistance and significant pressure loss. They feature a simple structure, low cost, and a wide range of adjustable settings. Ball valves overcome the aforementioned disadvantages of butterfly valves, but they have high frictional resistance at their sealing surfaces. Butterfly valves are generally used as control valves, while ball valves are used as shut-off valves. Of course, ball valves are not used in large-diameter pipelines, as it is difficult to manufacture large spherical surfaces. Ball valves are suitable for liquids and gases that do not contain particulate impurities; they result in low fluid pressure loss, good sealing performance, but at a higher cost. Generally, ball valves are used for small diameters, while butterfly valves are used for large diameters

General application conditions for butterfly valves: 1. Low pressure (below 16 kilograms). 2. Large diameters. 3. Average sealing performance and service life. 4. Low cost. General application conditions for ball valves: 1. Small diameters (minimum DN8MM). 2. High pressure (above 16 kilograms). 3. Higher requirements regarding service life and sealing performance. I’m not sure if this answer satisfies the original poster; I’m quite familiar with these valves! :lol :lol QQ: 928976489 (Italian LAPAR)

Both ball valves and butterfly valves are primarily used for switching purposes. Three-eccentric butterfly valves can currently achieve an ANSI 2500# rating and withstand temperatures of up to 1000 degrees Fahrenheit. Therefore, only the design temperature and pressure need to be considered. Both types of valves can be used, but ball valves are much more expensive. Structurally, since the valve disc of a butterfly valve is exposed to the medium when it is fully open, the pressure drop across a butterfly valve is higher than that of a ball valve, and it is not possible to use it for passing balls through. As a result, ball valves are used in long-distance pipelines (in compliance with API6D standards). In the chemical industry, three-eccentric butterfly valves are commonly used as alternatives to ball valves for large-diameter shut-off applications, owing to their lower cost, lighter weight, ease of operation, and longer sealing life

In my opinion, there isn’t much difference, because what matters is whether it’s a manually operated ball valve or a butterfly valve； It’s still pneumatic; both ball valves and butterfly valves require a relatively high torque when there is a high pressure difference ； For ball valves of type O, it is better to close them, as they can achieve a very high level of sealing. Ball valves of type V are more suitable for handling media that contain impurities or fibers, though their sealing performance is slightly lower. Butterfly valves have metal seals; FISHER models can achieve a V-grade seal performance, while those with softer seals can reach a VI-grade performance. The media flowing through them is usually quite pure, and the temperature can go up to over 400 degrees. Suggestion: When you ask your question, please describe the general operating conditions, so that it’s possible to conduct a comparison and provide you with more appropriate advice.

Ball valves are characterized by a simple structure, small size, few components, light weight, rapid switching, easy operation, low fluid resistance, and high requirements for manufacturing precision. It is generally not suitable for use in high-temperature media. Butterfly valves are characterized by their simple structure, small external dimensions, and light weight, making them suitable for manufacturing valves with large pipe diameters. Suitable for low pressure.