The closing part of the butterfly valve is a disc shape, which rotates around a fixed axis in the valve body to open, close and adjust the fluid channel.
Advantage
Simple structure, small size and light weight;
Under low pressure, a good seal can be achieved;
Easy to open and close, labor saving, low fluid resistance, and can be operated frequently;
Can transport mud, with minimal liquid accumulation at the pipe mouth;
Good adjustment performance.
Disadvantages
Poor tightness;
The operating pressure and operating temperature range are small.
Butterfly valves are developing fastest now, and are developing towards high temperature, high pressure, large diameter, high tightness, excellent adjustment performance, and long life. They have partially replaced gate valves, globe valves, and ball valves.
According to the structure, the butterfly valve can be divided into center seal type, single eccentric seal type, double eccentric seal type and triple eccentric trial butterfly valve. The center seal type belongs to the earlier butterfly valve form; compared with the center seal type, the single eccentric seal butterfly valve has a more complicated structure, a slightly higher cost, better sealing performance, longer service life, and higher operating pressure; double eccentric seal type and Compared with the single-eccentric type, the three-eccentric butterfly valve has a more complicated structure, higher manufacturing cost, better sealing performance, longer service life and higher use pressure.
The characteristics of industrial special butterfly valve can withstand high temperature, and the applicable pressure range is also high. The nominal diameter of the valve is large. The valve body is made of carbon steel. The sealing ring of the valve plate uses a metal ring instead of a rubber ring. Large high-temperature butterfly valves are manufactured by welding steel plates, and are mainly used for flue gas ducts and gas pipes of high-temperature media.
Installation and maintenance should pay attention to the following matters:
During installation, the disc should stop at the closed position;
The opening position should be determined according to the rotation angle of the butterfly board;
Butterfly valves with bypass valves should be opened before opening;
The installation should be carried out according to the manufacturer's installation instructions. The heavy-weight butterfly valve should be installed with a solid foundation.
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