What Is a Flanged Butterfly Valve?
The butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. Moreover, it can be opened and closed quickly by rotating 90 °, and the operation is simple. At the same time, the valve has good fluid control characteristics. The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0 ° and 90 °. When it rotates to 90 °, the valve is fully opened. When the flange butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is small, so it has good flow control characteristics. The butterfly valve has two types of sealing: spring and metal. Elastically sealed valve, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.
Flange butterfly valve
- The butterfly valve is simple in structure, small in size and light in weight, and consists of only a few parts. Moreover, it can be opened and closed quickly by rotating 90 °, and the operation is simple. At the same time, the valve has good fluid control characteristics. The butterfly plate of the butterfly valve is installed in the diameter direction of the pipe. In the cylindrical channel of the butterfly valve body, the disc-shaped butterfly plate rotates around the axis, and the rotation angle is between 0 ° and 90 °. When it rotates to 90 °, the valve is fully opened. When the flange butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated by the valve is small, so it has good flow control characteristics. The butterfly valve has two types of sealing: spring and metal. Elastically sealed valve,
- The rotation center of the butterfly plate (that is, the center of the valve stem) is located on the center line of the valve body and on the sealing surface section of the butterfly plate. The seat is made of synthetic rubber. When closed, the outer sealing surface of the butterfly plate squeezes the synthetic rubber valve seat, causing the valve seat to elastically deform, thereby forming an elastic force as the sealing specific pressure to ensure the seal of the butterfly valve. The flange butterfly valve seal structure uses polytetrafluoroethylene and synthetic rubber to form a composite valve seat. Its characteristics are that the elasticity of the valve is still provided by synthetic rubber and uses the characteristics of polytetrafluoroethylene such as low friction coefficient, not easy to wear, not easy to age, etc. Butterfly valve life is increased.
- The flange butterfly valve has the same sealing principle and structural characteristics as the ordinary centerline butterfly valve.
- The flange butterfly valve seal structure adopts polytetrafluoroethylene, synthetic rubber and phenolic resin to form a composite valve seat, which makes the valve seat more elastic and stronger. At the same time, the butterfly plate is fully covered with polytetrafluoroethylene, so that the butterfly plate has strong corrosion resistance.
- The main features of flange butterfly valve are:
- 1. Compact and lightweight, easy to disassemble and maintain, and can be installed in any position.
- 2. The structure is simple and compact, the operating torque is small, and the 90 ° rotation opens quickly.
- 3. The flow characteristics are straight, and the adjustment performance is good.
- 4. The connection between the butterfly plate and the valve stem adopts a pinless structure, which overcomes the possible internal leakage points.
- 5. The outer circle of the butterfly plate adopts a spherical shape, which improves the sealing performance and prolongs the service life of the valve. It still maintains zero leakage when it is opened and closed under pressure for more than 50,000 times.
- 6, seals can be replaced, and the seal is reliable to achieve a two-way seal.
- 7. The butterfly board can be spray coated according to user requirements, such as nylon or PTFE.
- 8. The valve can be designed into flange connection and wafer connection.
- 9. The driving method can be manual, electric or pneumatic.
- Flange butterfly valve is suitable for water supply and drainage, sewage, food, heating, gas, marine, hydropower, metallurgy, energy system and light textile industries with temperature 120 or 150 and nominal pressure 1.6MPa. It is especially suitable for two-way sealing and Where the valve body is susceptible to rust, it is used to adjust the flow rate and intercept the medium.
- Valves with metal seals generally have a longer life than valves with elastic seals, but it is difficult to achieve a complete seal. Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being temperature limited.
- If butterfly valves are required for flow control, the main thing is to choose the correct valve size and type. The structural principle of the butterfly valve is particularly suitable for making large-caliber valves. Butterfly valves are widely used not only in general industries such as petroleum, gas, chemical, and water treatment, but also in cooling water systems in thermal power stations. Commonly used butterfly valves are wafer type butterfly valves and flange type butterfly valves. Wafer type butterfly valve uses double-headed bolts to connect the valve between two pipeline flanges. Flange type butterfly valves have flanges on the valve, and bolts are used to connect the two ends of the valve to the pipeline flange.
- When in the fully open position, the thickness of the disc is the only resistance when the medium flows through the valve body, so the pressure generated by the valve will be small, and it is estimated that it has good flow control characteristics. Butterfly valve has two types of sealing: elastic seal and metal seal. Elastically sealed valve, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.
- Valves with metal seals generally have a longer life than valves with elastic seals, but it is difficult to achieve a complete seal. Metal seals can adapt to higher operating temperatures, while elastic seals have the disadvantage of being temperature limited.
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- Design and manufacture: GB / T12238-89 "General valve flange and wafer connection butterfly valve" JB / T8527-1997 "Metal seal butterfly valve" JIS
- Flange size: PN = 1.0MPa according to JB / T82.1-94 (that is, the original standard JB82-59) "Protruding face welding steel pipe flange"
- PN = 1.6MPa according to GB9113.3-88 "Convex integral steel pipe flange"
- PN = 2.5MPa according to GB9113.4-88 "Convex integral steel pipe flange"
- Structure length: according to GB12221-89 "Flange connection metal valve structure length"
- Inspection and test: According to GB / T13927-92 "General Valve Pressure Test"