Working Principle of Butterfly Valve and Emergence of New Butterfly Valve

Figure 1: A butterfly valve with simple structure.

Butterfly valve is a kind of valve that opens, closes, and adjust medium flow by using disc type hoist to turn back and forth about 90 °. Butterfly valve is not only simple in structure, small in size, light in weight, low in material consumption, small in installation size and driving torque, with simple and rapid operation, but also has good flow regulation function and closing sealing characteristic. It is one of the fastest developing valve varieties in recent decades.

Butterfly valve enjoys a wide range of application. The varieties and quantities of the valve continue to expand, and they are developing towards high temperature, high pressure, large diameter, high-quality sealing, long service life, excellent regulation characteristics and multi-function in one valve. Its reliability and other performance indexes have reached a high level.

Figure 2: The diagram of how a butterfly valve control the media flow.

Butterfly valve has relatively less fluid resistance when it is fully opened. It can perform sensitive flow control, when it is opened between 15° and 70°.Therefore, butterfly valves are widely used in the field of large-diameter adjustment. Since the movement of butterfly plate is characteristic in wiping, most butterfly valves can be used for media with suspended solid particles. Depending on the strength of the sealing element, it can also be used for powdery and granular media.

Butterfly valve is suitable for flow adjustment. As the pressure loss of the butterfly valve in the pipe is relatively large, which is approximately three times as large as that of the sluice valve, the influence of the pressure loss on the pipeline system should be fully considered when selecting the butterfly valve, and the strength of the butterfly plate bearing the pressure of the pipeline medium when it is closed should also be considered. In addition, the operating temperature limitations of the resilient seat material at high temperature must be considered.

Figure 3: The diagram of manual sluice valve.

Butterfly valve has small structural length and overall height, fast opening and closing speed, and great fluid control characteristic. The structural principle of butterfly valve is most suitable for making large-diameter valve. The most important thing is to select the proper specification and type of butterfly valve so that it can work properly and effectively, when it is required to control flow.

Emergence of Butterfly Valve in New Form

With the wide application of chemical resistant synthetic rubber in butterfly valve, Improvements in its performance are made. As synthetic rubber has the characteristics of corrosion resistance, erosion resistance, stable size, good resilience, easy forming, low cost, etc., synthetic rubber with different properties can be selected according to different use requirements to meet the service conditions of butterfly valves.

Figure 4: The diagram of synthetic rubber used in making butterfly valve.

Because polytetrafluoroethylene (PTFE) has the characteristics of strong corrosion resistance, stable performance, not easy to aging, low friction coefficient, easy to form, and stable size, and can improve its comprehensive performance by stuffing and adding appropriate materials, so as to obtain butterfly valve sealing materials with better strength and lower friction coefficient, which overcomes the limitations of synthetic rubber. Therefore, the high polymer materials represented by polytetrafluoroethylene and their stuff materials have been widely used in butterfly valves, which further improves the performance of butterfly valves, and produces butterfly valves with bearing higher temperature and lager pressure range, reliable sealing and longer service life.

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