Nov.07.2024
Butterfly valves and ball valves are two of the most widely used and versatile types of valves in pipelines. Both are simple to operate and serve the function of stopping and cutting off pipeline media. They operate on the quarter-turn principle, requiring a 90-degree rotation from fully open to fully closed. They are employed for controlling the flow of various gases or liquids under different temperatures and pressures. Both ball valves and butterfly valves are favored for their relatively low cost, extended lifespan, and reliability. However, certain differences exist that can assist users in making a choice between the two.
Main Differences Between Butterfly Valves And Ball Valves
1. Structural
Structurally, the main difference between ball valves and butterfly valves lies in their closure elements. The closure element of a butterfly valve is a disc, while that of a ball valve is a sphere. Butterfly valves can regulate flow through the degree of opening, which is not possible with ball valves.
A butterfly valve consists of four parts: the valve body, seat, disc, and stem, all of which are exposed and visible to the naked eye. On the other hand, a ball valve is composed of a valve body, a spherical core (the ball), and a stem. The core is inside the valve body, with only a portion visible to the naked eye.
2. Sealing and Diameter
Butterfly valves are characterized by fast opening and closing speeds, simple structure, and low cost, but they have poor sealing and pressure-bearing capabilities. Ball valves can achieve rapid opening and closing and complete sealing under high pressure and temperature. Therefore, comparatively, the sealing performance of ball valves is better than that of butterfly valves. However, due to limitations in size and operating resistance, it is difficult for ball valves to achieve large diameters, while the structural principles of butterfly valves are particularly suitable for making large-diameter valves.
3. Operating Temperature and Pressure Resistance
From the perspective of operating temperature, due to sealing material and structural reasons, ball valves are not suitable for steam media, whereas butterfly valves can be used for conventional saturated steam media (below 350 degrees).
Butterfly valves, with their relatively simple structure, are generally used for low-pressure applications, while the structural form of ball valves is relatively more complex and can withstand higher pressures.
4. Operating Torque
In terms of operating torque, butterfly valves are triple eccentric metal-sealed butterfly valves, so their opening and closing torque is very small. As the diameter of a ball valve increases, the contact area of the sealing surface also increases exponentially, resulting in very high opening and closing torque for large-diameter ball valves.
Different Choices Between Butterfly Valves And Ball Valves
The above-discussed differences between ball valves and butterfly valves provide a basis for making choices between the two. When selecting valves, customers need to consider factors such as space, media, and pressure on-site comprehensively.
1. High-Pressure Capability of Ball Valves
One significant difference between butterfly valves and ball valves is that ball valves can withstand high pressures, with a maximum pressure capacity of up to 900 kilograms.
2. Comparative Processing
In terms of processing, manufacturing molds for ball valves are relatively more convenient compared to butterfly valves. High-pressure ball valves can be forged during processing.
3. Diameter Comparison
Butterfly valves are rarely made with diameters below 50, whereas ball valves can be manufactured with a minimum diameter of 8. For diameters below 40, the cost of butterfly valves might be higher compared to ball valves.
4. Selection
However, under the same conditions, some may choose to use butterfly valves based on cost restrictions, while others may opt for ball valves based on size requirements.
