Differences Between Butterfly Valves and Ball Valves

The biggest difference between butterfly valves and ball valves 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 the butterfly valve and the valve core of the ball valve rotate around their own axes;

Differences Between Butterfly Valves and Ball Valves

The biggest difference between butterfly valves and ball valves 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 the butterfly valve and the valve core of the ball valve rotate around their own axes; the butterfly valve can adjust the flow rate through the opening degree, while it is not easy for the ball valve to do this.

Butterfly valves are characterized by fast opening and closing speed, simple structure and low cost, but poor tightness and pressure-bearing capacity. Ball valves have similar characteristics to gate valves, but due to the limitations of volume and opening/closing resistance, it is difficult to achieve large diameters.

During the opening and closing process, the ball valve operates under the clamping force of the valve seats at both ends. Its opening and closing torque is larger than that of the hemispherical valve, and the difference in opening and closing torque becomes more obvious as the nominal diameter increases. The opening and closing of the butterfly valve must overcome the deformation of the rubber, resulting in a larger torque. In contrast, gate valves and globe valves take a long time to operate and are laborious.

Ball valves and plug valves belong to the same type of valve. Their closing part is a ball, which rotates around the center line 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.

The structural principle of butterfly valves is particularly suitable for manufacturing large-diameter valves. The valve plate of a butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the butterfly valve body, the disc-shaped valve plate rotates around the axis with a rotation angle between 0° and 90°. When rotated to 90°, the valve is in a fully open state. It has a simple structure, low cost and a wide adjustable range. Ball valves are usually suitable for liquids and gases without particulate impurities, with small fluid pressure loss, good sealing performance and high cost. Comparatively speaking, the sealing performance of ball valves is better than that of butterfly valves. The sealing of ball valves relies on the valve seat pressing tightly against the ball surface for a long time, which definitely wears faster than that of hemispherical valves. The sealing of ball valves usually uses flexible materials, and it is also difficult to use in high-temperature and high-pressure pipelines. The sealing of butterfly valves uses rubber as an intermediary, and its metal hard sealing performance is far inferior to that of hemispherical valves, ball valves and gate valves. After long-term use of the hemispherical valve, the valve seat will also have slight wear, which can continue to be used through adjustment. During the opening and closing process of the valve stem and packing, the valve stem only needs to rotate 90°. When there is a sign of leakage, slightly tightening the bolts of the packing gland can achieve no leakage at the packing. For other valves, small leaks are barely used and large leaks require valve replacement.