
Main classification of butterfly valve
1. According to the driving mode
(1) electric butterfly valve
(2) Pneumatic butterfly valve
(3) Hydraulic butterfly valve
(4) Manual butterfly valve
2. According to the structural form:
(1) Center seal butterfly valve
(2) Single eccentric sealing butterfly valve
(3) Double eccentric sealing butterfly valve
(4) Triple eccentric sealing butterfly valve
3. Material of sealing surface:
(1) Soft seal butterfly valve.
1) The sealing pair is composed of non-metallic soft material to non-metallic soft material.
2) The sealing pair is composed of metallic hard material and non-metallic soft material.
(2) Metal hard seal butterfly valve. The sealing pair is made of metal hard material to metal hard material.
4. According to the sealing form:
(1) Forced seal butterfly valve.
1) Elastic sealing butterfly valve: The sealing specific pressure is generated by the elasticity of the valve seat or valve plate when the valve plate squeezes the valve seat when the valve is closed.
2) Applied torque sealing butterfly valve: The sealing-specific pressure is generated by the torque applied to the valve shaft.
(2) Pressure sealing butterfly valve: The sealing specific pressure is generated by the pressure of the elastic sealing element on the valve seat or valve plate.
(3) Automatic sealing butterfly valve: the sealing specific pressure is automatically generated by the medium pressure.
5. According to the working pressure:
(1) Vacuum butterfly valve. A butterfly valve whose working pressure is lower than the standard stack atmospheric pressure.
(2) Low-pressure butterfly valve. Butterfly valve with nominal pressure PN<1.6MPa.
(3) Medium-pressure butterfly valve. Butterfly valve with nominal pressure PN of 2.5–6.4MPa.
(4) High-pressure butterfly valve. Butterfly valve with nominal pressure PN of 10.0–80.0MPa.
(5) Ultra-high pressure butterfly valve. Butterfly valve with nominal pressure PN>100MPa.
6. According to the working temperature:
(1) High temperature. Butterfly valve for t>450 °C.
(2) Medium temperature butterfly valve. 120 C<t<450 ℃ butterfly valve.
(3) Normal temperature butterfly valve. A 40C<t<120 °C butterfly valve.
(4) Cryogenic butterfly valve. A 100<t< a 40 °C butterfly valve.
(5) Cryogenic butterfly valve. t<-100 °C butterfly valve.
7. According to the connection method:
(1) Wafer butterfly valve
The butterfly plate of the wafer butterfly valve is installed in the diameter direction of the pipeline. The valve is fully open.
The wafer butterfly valve has a simple structure, small size, and light weight. Butterfly valves have two sealing types: elastic seal and metal seal. For elastic sealing valves, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.
- Flanged butterfly valve
The flange butterfly valve is a vertical plate structure, and the valve stem is the sealing ring of the integral metal hard seal valve
It is a composite structure of flexible graphite plate and stainless steel plate, installed on the valve body, and the sealing surface of the butterfly plate is surfaced with stainless steel. The sealing ring of the soft seal valve is made of nitrile rubber and is installed on the butterfly plate.
- Lug-type butterfly valve
- Welded butterfly valve
The welded butterfly valve is a non-hermetic butterfly valve, which is widely used in pipelines with medium temperature ≤ 300°C and nominal pressure of 0.1Mpa in the production process of building materials, metallurgy, mining, electric power, etc., to connect, open and close or adjust the medium volume.

Functional use of butterfly valve
The butterfly valve is usually less than 90° from fully open to fully closed. The butterfly valve and butterfly rod have no self-locking ability. To position the butterfly plate, a worm gear reducer should be installed on the valve rod. The use of the worm gear reducer not only enables the butterfly plate to have self-locking ability, and makes the butterfly plate stop at any position, but also improves the operating performance of the valve. The characteristics of the industrial special butterfly valve: are high-temperature resistance, high-pressure range, large nominal diameter of the valve, the valve body is made of carbon steel, and the sealing ring of the valve plate is replaced by a metal ring instead of a rubber ring. Large-scale high-temperature butterfly valves are manufactured by welding steel plates and are mainly used for flue gas ducts and gas pipelines for high-temperature media.
Selection of butterfly valve
The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline. The butterfly valve is simple in structure, small in size, and light in weight. It consists of only a few parts, and it can be opened and closed quickly only by rotating 90°. The operation is simple, and the valve has good fluid control characteristics. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the resistance when the medium flows through the valve body, so the pressure drop generated by the valve is very small, so it has good flow control characteristics.
If the butterfly valve is required to be used as a flow control, the main thing is to correctly select the size and type of the valve. The structural principle of the butterfly valve is especially suitable for the production of large-diameter valves. Commonly used butterfly valves include wafer butterfly valves and flanged butterfly valves. The wafer butterfly valve is used to connect the valve between two pipe flanges with stud bolts. The flanged butterfly valve has flanges on the valve, and the flanges at both ends of the valve are connected to the pipe flanges with bolts.
Butterfly valve, as a component used to realize on-off and flow control of pipeline systems, has been widely used in many fields such as petroleum, the chemical industry, metallurgy, hydropower, and so on. In the known butterfly valve technology, its sealing form mostly adopts a sealing structure, and the sealing material is rubber, polytetrafluoroethylene, etc. Due to the limitations of structural features, it is not suitable for industries such as high-temperature resistance, high-pressure resistance, corrosion resistance, and wear resistance.
An existing relatively advanced butterfly valve is a triple-eccentric metal hard-sealed butterfly valve. The valve body and the valve seat are connected components, and the sealing surface of the valve seat is surfaced with heat-resistant and corrosion-resistant alloy materials. The multi-layer soft stacked sealing ring is fixed on the valve plate. Compared with the traditional butterfly valve, this butterfly valve has high-temperature resistance, easy operation, and no friction when opening and closing. The advantages of excellent sealing performance and extended service life.
Where Butterfly Valves Are Applicable
Butterfly valves are suitable for flow regulation. Since the pressure loss of the butterfly valve in the pipeline is relatively large, the robustness of the butterfly plate to withstand the pressure of the pipeline medium should also be considered when it is closed. In addition, the limitation of the operating temperature of the elastic seat material at high temperatures must also be considered. The structural length and overall height of the butterfly valve are small, the opening and closing speed is fast, and it has good fluid control characteristics. The structural principle of the butterfly valve is most suitable for making large-diameter valves. When the butterfly valve is required to be used for flow control, the most important thing is to correctly select the size and type of the butterfly valve so that it can work properly and effectively.
Usually, in throttling, regulating control, and mud medium, the structure length is required to be short and the opening and closing speed is fast (1/4 turn). For low-pressure cut-off (small pressure difference), a butterfly valve is recommended.
Butterfly valves can be used for double-position adjustment, narrowing channels, low noise, cavitation and gasification, a small amount of leakage to the atmosphere, and abrasive media.
When throttling adjustment is required under special working conditions or strict sealing is required, or the butterfly valve is used under severe wear, low temperature (cryogenic), and other working conditions, it is necessary to use a specially designed triple eccentric or double eccentric metal sealing belt adjustment device. Butterfly valve.
Butterfly valves are suitable for freshwater, sewage, seawater, salt water, steam, natural gas, food, medicine, oil, and various types of valves that require complete sealing, zero leakage in gas test, high life expectancy, and working temperature between -10 degrees and 150 degrees. Acid-base and other pipelines.
The soft-seal eccentric butterfly valve is suitable for two-way opening and closing and adjustment of ventilation and dust removal pipelines and is widely used in gas pipelines and waterways in metallurgy, light industry, electric power, petrochemical systems, etc.
The metal-to-metal wire-sealed double eccentric butterfly valve is suitable for gas, oil, acid, and alkali pipelines such as urban heating, gas supply, water supply, etc., as a regulating and throttling device.
The metal-to-metal surface-sealed triple eccentric butterfly valve is not only used as a program control valve for a large pressure swing adsorption (PSA) gas separation device but also can be widely used in petroleum, petrochemical, chemical, metallurgy, electric power, and other fields. It is an excellent choice for gate valves and globe valves. replacement product.
Installation And Maintenance of Butterfly Valve
1. When installing, the disc should stop at the closed position.
2. The opening position should be determined according to the rotation angle of the butterfly plate.
3. For butterfly valves with bypass valves, the bypass valves should be opened before opening.
4. It should be installed according to the installation instructions of the manufacturer. For heavy butterfly valves, a firm foundation should be set up.