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Structure and performance principle of butterfly valve and its classification
Jun 04, 2018

Butterfly valves are commonly used valves in industrial water systems. They are small valves with high cost performance and become common valves for pipelines. The main products of butterfly valves are clamped soft seal butterfly valves and flanged butterfly valves. Although butterfly valves are less than gate valves, there are many differences between them to suit different conditions. This article Shanghai butterfly valve manufacturer - Shanghai mill valve will ask you to introduce butterfly valve performance, butterfly valve principle, butterfly valve structure, butterfly valve classification, to help you better carry out butterfly valve selection.

Butterfly valve closure - butterfly plate is disc shaped, revolving around the axle in the valve seat 90 degrees can start and close and adjust the medium. It is widely used in medium and low pressure large caliber pipelines. The structure of the butterfly valve is shown as shown.

1, the classification of butterfly valves:

According to the structure classification, butterfly valves are mainly divided into middle and eccentric ones, including eccentric, eccentric, double eccentric and three eccentric butterfly valves.

Related butterfly valve products: clip butterfly valve, signal butterfly valve, flange butterfly valve, large diameter flange butterfly valve and so on.

2, the performance principle of butterfly valve

Butterfly valve uses the valve plate along the centerline rotation structure, so the valve is small. By rotating the handle 90 degrees or worm wheel and other driving mode, the valve plate and the medium flow direction parallel can open the valve. Therefore, the butterfly valve has the characteristics of simple structure, small size, light weight, small installation size, convenient operation and quick opening and closing. At the same time, it also has the characteristics of sealing and flow regulation. However, due to the large resistance of disc, medium pressure has great influence on valve opening and closing, so it is not suitable for high pressure environment.

The former butterfly valve is restricted by technology and sealing material, most of the structure is medium and linear soft seal, that is, the seat is mostly rubber, plastic, butterfly plate as metal or metal coated rubber or plastic. In recent years, with the rapid development of science and technology, the butterfly valve has developed a new structural type. The eccentric metal seal butterfly valve is one of them. The valve seat and butterfly plate seal face of eccentric metal seal is made up of metal cemented carbide material, or the butterfly plate is made up of soft and hard material (non metal layer clip metal layer). The butterfly valve can endure high temperature, low temperature resistance, abrasion resistance, erosion resistance, good sealing performance and long service life, so it is widely used.

Butterfly valves have replaced gate valves, globe valves, throttle valves and ball valves in a wide range. They are one of the valve varieties that have developed rapidly in recent years.

(1) performance comparison of butterfly valve:

The performance advantages of butterfly valve are mainly concentrated in small volume, simple structure, fast opening and closing of these three points, the disadvantages are also obvious that the pressure loss of the pipe flow medium is relatively large, and the high pressure environment is difficult to open and close.

(2) the different structure of butterfly valve classification and difference:

The sealing performance of middle line butterfly valve, single eccentric butterfly valve, double eccentric butterfly valve and three eccentric butterfly valve is increased in turn, and the life span is also increased in turn, but the structure is more difficult and the cost is increasing. Therefore, unless there are special requirements, it is often more economical and suitable for butterfly valves.