Utmost Flow Control Technology Co., Ltd.
Utmost Flow Control Technology Co., Ltd.

The Difference Between Ball Valve and Butterfly Valve

The biggest difference between the ball valve and the butterfly valve is that the opening and closing part of the butterfly valve is a plate, while the ball valve is a ball. The valve plate of the butterfly valve and the spool of the ball valve rotate around their own axis; For lifting movement; butterfly valve and gate valve can adjust the flow through the opening degree; ball valve is not easy to do this.


1. Ball valves and butterfly valves have different characteristics


The butterfly valve is characterized by fast opening and closing speed, simple structure and low cost, but its tightness and pressure bearing capacity are not good. The characteristics of ball valves are similar to those of gate valves, but limited by volume and opening and closing resistance, it is difficult to achieve large diameters.


2. The structure and principle of ball valve and butterfly valve are different


The structural principle of the butterfly valve is especially suitable for making large-diameter valves. The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0° and 90°. When the rotation reaches 90°, the valve is fully open. The utility model has the advantages of simple structure, low cost and large adjustable range. Ball valves are generally suitable for liquids and gases without particulate impurities, with small fluid pressure loss, good sealing performance, and high cost. In comparison, the sealing of ball valves is better than that of butterfly valves.


The ball valve is sealed by the long-term extrusion of the valve seat on the spherical surface. It must wear faster than the semi-ball valve. The seal of the ball valve is usually made of flexible materials, and it is difficult to use in high-temperature and high-pressure pipelines. Butterfly valve sealing uses rubber as the intermediary, which is far behind the metal hard sealing performance of hemispherical valves, ball valves, and gate valves. After the hemispherical valve is used for a long time, the valve seat will also produce a small amount of wear, which can continue to be used through adjustment. The valve stem and packing only need to rotate 90° during the opening and closing process. A few bolts can achieve no leakage at the packing, while other valves are still barely used for small leaks, and valves are replaced for large leaks.


3. The working principle of ball valve and butterfly valve is different


During the opening and closing process, the ball valve operates under the tight force of the valve seats at both ends. Its opening and closing torque is larger than that of the hemispherical valve. The larger the nominal diameter is, the more obvious the opening and closing torque difference is. The opening and closing of the butterfly valve is to overcome the deformation of the rubber. To achieve, the torque is greater. However, gate valves and globe valves operate for a long time and are laborious. Ball valve and plug valve belong to the same type of valve, only its closing part is a sphere, and 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 media.


At present, the butterfly valve, as a component used to realize the on-off and flow control of the pipeline system, has been widely used in many fields such as petroleum, chemical industry, metallurgy, and hydropower. In the known butterfly valve technology, its sealing form mostly adopts a sealing structure, and the sealing material is rubber, polytetrafluoroethylene, etc. Due to the limitations of structural features, it is not suitable for industries such as high temperature resistance, high pressure resistance, corrosion resistance, and wear resistance. An existing relatively advanced butterfly valve is a triple-eccentric metal hard-sealed butterfly valve. The valve body and the valve seat are connected components, and the sealing surface of the valve seat is surfacing with heat-resistant and corrosion-resistant alloy materials. The multi-layer soft stacked sealing ring is fixed on the valve plate. Compared with the traditional butterfly valve, this butterfly valve has high temperature resistance, easy operation, and no friction when opening and closing. The advantages of excellent sealing performance and extended service life.

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