Views: 0 Author: Site Editor Publish Time: 2024-06-07 Origin: Site
In industrial fluid control systems, valves are the core control components, and their selection directly affects the operating efficiency, safety, and economy of the system. Ball valves and butterfly valves, as two common types of valves, each have their unique structural features, performance advantages, and applicable scenarios. This article will deeply analyze the technical differences between ball valves and butterfly valves and provide scientific valve selection references for industrial practitioners in combination with actual application scenarios.
The ball valve uses a spherical body as the opening and closing part, with a circular passage in the middle of the sphere. The valve stem is connected to the sphere, and by rotating the valve stem, the sphere rotates 90° around the center line of the valve body to achieve the opening and closing of the valve. When the sphere passage coincides with the pipeline axis, the valve is fully open, and the fluid can pass through without obstruction; after the sphere rotates 90°, its spherical surface completely blocks the passage, and the valve is closed. Some ball valves adopt a floating ball or trunnion ball design. The floating ball can be closely attached to the valve seat under the action of the medium pressure, while the fixed ball relies on the elastic deformation of the valve seat to achieve sealing.
The opening and closing part of the butterfly valve is a disc-shaped butterfly plate, which is installed on the central shaft of the valve body. By rotating the valve stem through the driving device, the butterfly plate rotates around the axis, and within the rotation range of 0°-90°, the opening and closing of the valve and flow regulation are achieved. When the butterfly plate is in the 0° position, the valve is fully open, and the fluid flow resistance is small; when the butterfly plate rotates to 90°, it is completely closed, blocking the fluid passage. According to the relative position and eccentricity of the butterfly plate and the valve seat, butterfly valves can be divided into center sealed butterfly valves, single eccentric butterfly valves, double eccentric butterfly valves, and triple eccentric butterfly valves. Different structural designs affect their sealing performance and applicable working conditions.
Ball valves generally offer superior sealing performance. In particular, ball valves with metal seals or high-performance soft sealing materials can form a tight sealing pair between the ball and the valve seat when closed, effectively preventing media leakage. Even under harsh working conditions such as high pressure and high temperature, they can still maintain good sealing. In contrast, the sealing performance of butterfly valves is greatly affected by their structure and sealing materials. The sealing performance of ordinary center sealed butterfly valves is relatively weak, while the eccentric butterfly valve has improved its sealing performance through optimized structural design, but overall, it still cannot match the sealing reliability of ball valves under extreme conditions.
