What is a butterfly valve: Butterfly valve opening and closing pieces is a disc-shaped butterfly plate, rotating around its own axis in the body, so as to achieve opening and closing or regulating valve called butterfly valve. The butterfly valve fully open to the whole is usually less than 900, the butterfly valve and the butterfly rod itself is not self-locking force, in order to disc positioning, to install a worm reducer on the stem. The use of worm reducer, not only can make the disc self-locking ability to stop the butterfly plate in any position, but also to improve valve performance. Industrial butterfly valve features high temperature, high pressure range, the valve nominal diameter, the valve body made of carbon steel, the valve ring using a metal ring instead of rubber ring. Large high temperature butterfly valve welded steel manufacturing, mainly for high temperature medium smoke duct and gas pipelines. Butterfly valve features: 1, opening and closing fast and convenient, labor-saving, fluid resistance is small, you can often operate. 2, simple structure, small size, light weight. 3, you can transport the mud, the liquid accumulated in the pipe port at least. 4, under low pressure, can achieve a good seal. 5, adjust the performance. The shortcomings of the butterfly valve are as follows: 1, the use of pressure and small working temperature range. 2, poor sealing. Butterfly valve classification: 1, according to the structure classification (1) center seal butterfly valve (2) single eccentric seal coal valve (3) double eccentric sealing butterfly valve (4) three eccentric sealing butterfly valve 2, according to the sealing surface material classification (1) Butterfly valve 1) The sealing pair is made of non-metallic soft material to non-metallic soft material. 2) The sealing pair is made of metal hard material to non-metal soft material. (2) metal seal butterfly valve. The sealing pair is made of metal hard material to metal hard material. 3. Classified by seal (1) Forced seal butterfly valve 1) Elastomeric seal butterfly valve. Sealing pressure ratio by the valve is closed when the valve plate squeeze valve seat, valve seat or valve plate flexibility 2) plus torque butterfly valve. Sealing than the pressure applied by the valve shaft torque (2) pressure sealing butterfly valve. Sealing than the pressure from the valve seat or valve plate elastic seal components generated pressure (3) automatic sealing butterfly valve. Sealing pressure is automatically generated by the media pressure. 4. Classified by working pressure (1) Vacuum butterfly valve. Work pressure is lower than the standard reactor atmosphere calendar butterfly valve. (2) low pressure butterfly valve. Butterfly valve with nominal pressure PN <1.6MPa. (3) medium pressure butterfly valve. Nominal pressure PN 2.5 - 6.4MPa butterfly valve. (4) high-pressure butterfly valve. Nominal pressure PN 10.0 - 80.0MPa butterfly valve. (5) Ultra-high pressure butterfly valve. Nominal pressure PN> 100MPa butterfly valve. 5. Classified by working temperature (1) High temperature butterfly valve. Butterfly valves with t> 450 C (2) Medium temperature butterfly valves. Butterfly valves of 120 C <t <450 C (3) Normal temperature butterfly valves. A 40C <t (4) low temperature butterfly valve. A 100 <t <a 40 C butterfly valve (E) ultra-low temperature butterfly valve. t <a 100 C butterfly valve 6. According to the connection classification (1) on the butterfly valve. (2) Flanged butterfly valve. (3) Bellow butterfly valve. (4) welded butterfly valve. Butterfly valve installation and maintenance should note the following: 1, the installation, the valve to stop in the closed position. 2, the opening position should be determined by the rotation angle of the disc. 3, with bypass valve butterfly valve, open the bypass valve should be opened before. 4, should be installed according to the manufacturer's installation instructions, the weight of the butterfly valve, should be set up a solid foundation. How to choose Butterfly butterfly valve installed in the pipe diameter direction. In the butterfly valve body cylindrical channel, the disc-shaped disc rotates about the axis, the rotation angle is between 0 ° -90 °, when rotated to 90 °, the valve is fully open state card. Butterfly valve structure is simple, small size, light weight, only a few components. And just turn 90 ° to quickly open and close, easy to operate, while the valve has good fluid control features. When the butterfly valve is fully open, the thickness of the disc is the only resistance to the flow of the medium through the valve body, so the pressure drop across the valve is small and therefore has good flow control characteristics. Butterfly valve seal and metal seal two types of seal. Flexible sealing valves, seals can be embedded in the body or attached to the butterfly plate around. Valves with metal seals generally have a longer life than elastomeric valves, but are harder to seal completely. Metal seals can adapt to higher operating temperatures, while flexible seals have temperature-limited defects. If the butterfly valve is required to be used as a flow control, the main choice is the correct size and type of valve. The structural principle of the butterfly valve is especially suitable for making large diameter valves. Butterfly valve not only in the oil, gas, chemical, water treatment and other general industry has been widely used, but also used in thermal power station cooling water system. Commonly used butterfly valve clamp butterfly valve and flange two. Butterfly Valve with the valve head bolt connection between two pipe flanges, flange type butterfly valve is a valve with a flange, both ends of the flange bolts with the valve connected to the pipe flange.
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