In fluid transport and process control systems, valves are key components for regulating, cutting off, and switching the flow direction of media. They come in many types and have diverse functions.
Butterfly valves, with their advantages of simple structure, rapid opening and closing, small footprint, and moderate cost, are widely used in numerous industrial and civil fields, becoming one of the important control devices in pipeline systems.
The basic structure of a butterfly valve consists of a valve body, a butterfly plate, a valve stem, and a sealing pair. The valve body is a circular cavity with connecting flanges or socket interfaces at both ends to adapt to different pipeline standards. The butterfly plate is a disc-shaped opening and closing element, installed in the valve body and capable of rotating around its own axis. By changing the relative angle between the butterfly plate and the flow channel, the cutting off or regulation of the media is achieved. The valve stem connects the drive device to the butterfly plate, transmitting the opening and closing torque. The sealing pair is located around the butterfly plate or at the contact surface between the valve body and the butterfly plate, ensuring that the media does not leak when closed. Its working principle is as follows: when the butterfly plate rotates to be parallel to the pipeline axis, the flow channel is fully open, and the resistance is minimal; when rotated to be perpendicular to the axis, the flow channel is closed, cutting off the medium. Flow regulation can be achieved at any angle between these two points, thus combining the functions of an on/off valve and a regulating valve.
Butterfly valves can be classified into center-line butterfly valves, eccentric butterfly valves, and soft-seal and hard-seal butterfly valves according to their structure and application. Center-line butterfly valves have a simple structure, with the sealing surface located at the valve stem axis, and are suitable for low-pressure, normal-temperature clean water or gas media; eccentric butterfly valves, through valve stem offset design, reduce friction between the butterfly plate and the valve body, improving sealing reliability and service life, and are often used in medium- and high-pressure conditions or conditions with large temperature differences; soft-seal butterfly valves use rubber or PTFE as the sealing surface, providing good sealing performance and suitable for applications with strict leakage control requirements; hard-seal butterfly valves use metal-to-metal sealing, are resistant to high temperatures and wear, and are suitable for steam, oil, and media containing particles.
The advantages of butterfly valves lie in their low flow resistance, low opening and closing torque, ease of operation, and compact size, making them suitable for installation in space-constrained pipelines. They are lightweight, less expensive than gate valves and ball valves, require less maintenance, and can be equipped with manual, electric, pneumatic, or hydraulic actuators for local or remote control. In industries such as water supply and drainage, HVAC, chemical processes, power auxiliary equipment, and food and pharmaceuticals, butterfly valves are widely used for the shut-off and flow regulation of water, air, oil, mildly corrosive liquids, and some gases.
With advancements in materials technology and manufacturing processes, high-performance butterfly valves are continuously improving in terms of high-temperature resistance, corrosion resistance, zero leakage, and long service life. They can also be integrated with intelligent control systems to achieve precise flow control and status monitoring. With their comprehensive performance and wide applicability, butterfly valves have become an indispensable and important piece of equipment in modern pipeline fluid control systems.
