What Do You Know about Butterfly Valves?

Butterfly valve is a valve that uses a disc type opening and closing member to open, close and adjust the fluid passage by turning back and forth about 90 degrees. Butterfly valve has simple structure, small volume, light weight, material consumption, small installation size, and small driving torque, easy and rapid operation, and also has good flow withering function and closing sealing characteristics, is one of the fastest growing varieties of valves in recent years. 

Especially in the United States, Japan, Germany, France, Italy and other industrially developed countries, the use of butterfly valves is very extensive. Its use of varieties and numbers continue to expand, and to high temperature, high pressure, large diameter, high sealing, long life, excellent adjustment characteristics and a valve multi-functional direction of development, its reliability and other performance indicators have reached a high level, and has partially replaced the globe valve, gate valve and ball valve. With the progress of butterfly valve technology, butterfly valve will become the dominant form of valve.

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, low cost, etc., and can be selected according to the different requirements of different properties of synthetic rubber to meet the working conditions of butterfly valves, and thus is widely used in the manufacture of butterfly valve lining and resilient seat.

To meet the use requirements of industrial applications such as high and low temperature, strong erosion, and long life, metal sealed butterfly valves have been developed greatly in the last decade or so. 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 seal butterfly valves have been widely used in industrial fields such as high and low temperature, strong erosion, and long life, and butterfly valves with large diameter (9750mm), high pressure (2.2kN/cm2), and wide temperature range (-102 to 606℃) have emerged, thus making the technology of butterfly valves reach a whole new level.

The butterfly valve has a small flow resistance when it is fully opened, and when it is opened between about 15° and 70°, it can also carry out sensitive flow control, thus the butterfly valve is very commonly used in the field of large diameter regulation and will gradually become the dominant valve type.

Since the movement of the butterfly valve plate is wiping, most butterfly valves can be used for media with suspended solid particles, and can also be used for powder and granular media depending on the strength of the seal.

Sealing principle of butterfly valve

The valve plate is processed to ensure that the sealing surface has a suitable surface roughness value, and the synthetic rubber seat is molded to form a suitable surface roughness value of the sealing surface. When the valve is closed, through the rotation of the valve plate, the outer sealing surface of the valve plate squeezes the synthetic rubber seat, so that the synthetic rubber seat produces elastic deformation and forms an elastic force as the sealing ratio pressure to ensure the sealing of the valve.