Butterfly Valve Working Principle

Butterfly valve is a valve that uses a disc-type opening and closing part to rotate back and forth about 90° to open, close or adjust the flow of the medium. Butterfly valves not only have simple structure, small size, light weight, low material consumption, small installation size, small driving torque, easy and rapid operation, but also have good flow adjustment function and closing sealing characteristics at the same time. They are the latest development in the past ten years. One of the fastest valve varieties. Butterfly valves are widely used. The variety and quantity of its use are still expanding, and are developing towards high temperature, high pressure, large diameter, high sealing, long life, excellent regulating characteristics, and multi-function in one valve. Its reliability and other performance indicators have reached a high level.
With the application of chemically resistant synthetic rubber to butterfly valves, the performance of butterfly valves has been improved. Since synthetic rubber has the characteristics of corrosion resistance, erosion resistance, dimensional stability, good resilience, easy to form, and low cost, synthetic rubber with different properties can be selected according to different usage requirements to meet the operating conditions of the butterfly valve.
Because polytetrafluoroethylene (PTFE) has strong corrosion resistance, stable performance, not easy to age, low friction coefficient, easy to form, and dimensional stability, its comprehensive properties can be improved by filling and adding appropriate materials to obtain better strength and friction. Butterfly valve sealing materials with lower coefficients overcome the limitations of synthetic rubber. Therefore, polymer materials represented by polytetrafluoroethylene and their filling modified materials have been widely used in butterfly valves, thereby improving the performance of butterfly valves. It has been further improved to create a butterfly valve with wider temperature and pressure range, reliable sealing performance and longer service life.
In order to meet the requirements of industrial applications such as high and low temperatures, strong erosion, and long life, metal-sealed butterfly valves have been greatly developed. With the application of high-temperature resistance, low-temperature resistance, strong corrosion resistance, strong erosion resistance, and high-strength alloy materials in butterfly valves, metal-sealed butterfly valves have been widely used in industrial fields such as high and low temperatures, strong erosion, and long life. Butterfly valves with large diameters (9~750mm), high pressures (42.0MPa), and wide temperature ranges (-196~606℃) have emerged, bringing butterfly valve technology to a whole new level.
When the butterfly valve is fully open, it has a small flow resistance. When it is opened between about 15° and 70°, it can perform sensitive flow control. Therefore, butterfly valves are very commonly used in the field of large-diameter adjustment.
Since the movement of the butterfly plate of the butterfly valve is wiping, most butterfly valves can be used in media with suspended solid particles. Depending on the strength of the seal, it can also be used for powdery and granular media.
Butterfly valves are suitable for flow regulation. Since the pressure loss of butterfly valves in the pipe is relatively large, about three times that of gate valves, when selecting butterfly valves, the impact of pressure loss on the pipeline system should be fully considered, and the strength of the butterfly plate to withstand the pressure of the pipeline medium when closed should also be considered. . In addition, the operating temperature limitations of the elastomeric seat material at elevated temperatures must also be considered.
The butterfly valve has a small structural length and overall height, fast opening and closing speed, and good fluid control characteristics. The structural principle of butterfly valve is most suitable for making large diameter valves. When a butterfly valve is required to control flow, the most important thing is to correctly select the specification and type of the butterfly valve so that it can work properly and effectively.
Generally, in throttling, regulating control and mud media, short structural length, fast opening and closing speed, and low pressure cutoff (small pressure difference) are required. Butterfly valves are recommended. Butterfly valves can be used when there are double-position adjustments, reduced-diameter channels, low noise, cavitation and vaporization, a small amount of leakage into the atmosphere, and abrasive media. Throttle adjustment under special working conditions, or working conditions requiring strict sealing, severe wear, low temperature (cryogenic), etc.