The most significant difference between a butterfly valve and a ball valve is that the opening and closing part of a butterfly valve is a plate, while that of a ball valve is a ball. Both the valve plate of a butterfly valve and the valve core of a ball valve rotate around their own axes. A butterfly valve can adjust the flow rate by the degree of opening, but it is not easy to do so with a ball valve. The characteristics of a butterfly valve are that it has a fast opening and closing speed, a simple structure, and a low cost, but it has poor tightness and pressure-bearing capacity. The features of a ball valve are similar to those of a gate valve, but due to the limitations of volume and opening and closing resistance, it is difficult to achieve a large diameter.

The structural principle of butterfly valves is particularly suitable for making large-diameter valves. The butterfly plate of a butterfly valve is installed along the diameter of the pipeline. Inside the cylindrical channel of the butterfly valve body, the circular butterfly plate rotates around the axis, with a rotation angle ranging from 0° to 90°. When it rotates to 90°, the valve is fully open. Its structure is simple, the cost is low, and the adjustable range is relatively large. Ball valves are usually suitable for liquids and gases without particle impurities. They have small fluid pressure loss and good sealing performance, but the cost is high. Compared with butterfly valves, the sealing performance of ball valves is better. The sealing of ball valves is achieved by the valve seat being constantly pressed against the ball surface. It is bound to wear out faster than that of half-balls. The sealing of ball valves usually uses flexible materials and is difficult to be used in high-temperature and high-pressure pipelines. The sealing of butterfly valves is achieved with rubber as an intermediary, which is far inferior to the metal hard sealing performance of half-balls, ball valves, and gate valves. After long-term use, the valve seat of a half-ball valve will also wear slightly. It can continue to be used by adjusting it. During the opening and closing process, the valve stem of a half-ball valve only needs to rotate 90°. When there are signs of leakage, the bolts of the packing gland can be tightened slightly to achieve no leakage at the packing. However, other valves still have to be replaced when they leak seriously after being used for a long time with minor leaks tolerated.

During the opening and closing process, the ball valve operates under the clamping force of the two end seats. Compared with the half ball valve, it requires a greater opening and closing torque, and the difference becomes more obvious as the nominal diameter increases. The opening and closing of the butterfly valve is achieved by overcoming the deformation of the rubber, which requires an even greater torque. In contrast, the operation of the gate valve and the globe valve is time-consuming and laborious.

Ball valves and plug valves belong to the same type of valve. The only difference is that the closing part of a ball valve is a sphere. The sphere rotates around the centerline of the valve body to achieve opening and closing. Ball valves are mainly used in pipelines to cut off, distribute and change the flow direction of the medium.