3 Optional
3.1 Type
The butterfly valve has different structures such as single eccentric, inclined plate type, center line type, double eccentric and triple eccentric. The medium pressure acts on the valve shaft and bearing through the butterfly plate. Therefore, when the flow resistance of high pressure and small diameter is large, the shaft diameter and the thickness of the butterfly plate will increase accordingly. If gate valves, ball valves or globe valves are used, from the aspects of sealing and flow resistance The analysis is more suitable than the butterfly valve.
3.1 Type
The butterfly valve has different structures such as single eccentric, inclined plate type, center line type, double eccentric and triple eccentric. The medium pressure acts on the valve shaft and bearing through the butterfly plate. Therefore, when the flow resistance of high pressure and small diameter is large, the shaft diameter and the thickness of the butterfly plate will increase accordingly. If gate valves, ball valves or globe valves are used, from the aspects of sealing and flow resistance The analysis is more suitable than the butterfly valve.
In recent years, the emergence of soft-seal gate valves in water systems has improved the shortcomings of gate valves that are easy to sediment. Its flow resistance is relatively small, and it can be repaired online. It is very suitable for small and medium diameters, so it has gradually been applied.
3.2 Sealing pair
The main advantages of the metal sealing butterfly valve are reliable sealing, long life, high temperature resistance, not easy to damage and tear, and high pressure bearing capacity. Therefore, it has been widely used in recent years, especially for key parts of engineering systems. If the rubber soft sealing butterfly valve is well designed and manufactured, it can be well sealed, and the large diameter can easily be changed on-line. However, rubber has aging problems and can only be used in working conditions where the temperature is not high, so it is widely used in tap water and water supply systems.
The main advantages of the metal sealing butterfly valve are reliable sealing, long life, high temperature resistance, not easy to damage and tear, and high pressure bearing capacity. Therefore, it has been widely used in recent years, especially for key parts of engineering systems. If the rubber soft sealing butterfly valve is well designed and manufactured, it can be well sealed, and the large diameter can easily be changed on-line. However, rubber has aging problems and can only be used in working conditions where the temperature is not high, so it is widely used in tap water and water supply systems.
Foreign metal sealing butterfly valves are also used in pumping stations, condensers, steam extraction systems and heat exchange systems in thermal power plants. Nuclear power plants are also used in pressure shell isolation, spray systems and brine, etc., oil storage isolation and steam in petroleum refining systems. Supply valve, desulfurization system and tail gas treatment, thermal cracking and catalytic unit. There are also petrochemical plants, cryogenic, slurry and papermaking systems.
For medium temperature and medium pressure conditions, it is better to use metal sealing butterfly valves. For places that require high reliability, long life, and long-term replacement, metal-sealed butterfly valves should also be used.
For the valve used for normal temperature water, if it is not very demanding, it will not be replaced for a long time or where it is inconvenient to replace, it is advisable to adopt a butterfly valve with a soft seal structure. If the quality of rubber can be guaranteed, large-diameter butterfly valves for water should still be mainly rubber seat butterfly valves.
4 Conclusion
The continuous emergence of new technology and new materials will improve the structural performance of the butterfly valve, expand the application range of the butterfly valve, and put forward updated requirements for the design and selection of the butterfly valve.
The continuous emergence of new technology and new materials will improve the structural performance of the butterfly valve, expand the application range of the butterfly valve, and put forward updated requirements for the design and selection of the butterfly valve.
Nortech is one of the leading industrial valve manufacturers in China with quality certification ISO9001.
Major products: Butterfly Valve, Ball Valve,Gate Valve, Check Valve, Globe Vavlve,Y-Strainers, Electric Acurator , Pneumatic Acurators .
Post time: Aug-20-2021