Butterfly valve also known as flap valve, is a simple structure of the control valve, but also can be used for low-pressure pipeline medium switch control. Butterfly valve refers to a kind of valve whose closing part (disc or disc) is a disc, which rotates around the valve shaft to open and close. It mainly plays the role of cutting off and throttling on the pipeline. The opening and closing part of butterfly valve is a disc-shaped butterfly plate, which rotates around its own axis in the valve body, so as to achieve the purpose of opening and closing or adjusting. Butterfly valve is applicable to the pipeline conveying various corrosive and non corrosive fluid media in generator, gas, natural gas, liquefied petroleum gas, city gas, cold and hot air, chemical smelting and power generation and environmental protection engineering systems, which is used to regulate and cut off the flow of medium.
Application of butterfly valve
Butterfly valves are suitable for flow regulation. Since the pressure loss of butterfly valve in the pipeline is relatively large, which is about three times of that of gate valve, the influence of pressure loss on pipeline system should be fully considered when selecting butterfly valve, and the firmness of butterfly plate bearing pipeline medium pressure when closing should also be considered. In addition, the working temperature limit of resilient seat material at high temperature must be considered.
The structure length and overall height of butterfly valve is small, the opening and closing speed is fast, and it has good fluid control characteristics. The structure principle of butterfly valve is most suitable for making large diameter valve. 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 butterfly valve, so that it can work properly and effectively.
Generally, in throttling, regulating control and mud medium, short structure length and fast opening and closing speed (1 / 4R) are required. Low pressure cut-off (small pressure difference), butterfly valve is recommended.
Butterfly valve can be used when double position adjustment, contraction channel, low noise, cavitation and gasification phenomenon, a small amount of leakage to the atmosphere, and abrasive medium.
When the butterfly valve is used under special working conditions, such as throttling regulation, strict sealing, severe wear and low temperature (deep cooling), special butterfly valve with special design metal sealing belt regulating device shall be used.
The middle line butterfly valve is suitable for fresh water, sewage, sea water, salt water, steam, natural gas, food, medicine, oil and various acid-base and other pipelines that require complete sealing, zero gas test leakage, high life requirements, and working temperature of – 10 ~ 150 ¡æ.
It is widely used in metallurgy, light industry, electric power, petrochemical system gas pipeline and water channel.
Metal to metal wire sealed double eccentric butterfly valve is suitable for urban heat supply, steam supply, water supply and gas, oil, acid and alkali pipelines as regulating and intercepting devices.
Metal to metal seal triple eccentric butterfly valve is not only used as program control valve of large pressure swing adsorption (PSA) gas separation device, but also widely used in petroleum, petrochemical, chemical, metallurgy, electric power and other fields. It is a good substitute for gate valve and stop valve.
Selection principle of butterfly valve
1. Compared with gate valve, the pressure loss of butterfly valve is larger, so it is suitable for pipeline system with less pressure loss requirements
2. Since the butterfly valve can be adjusted by flow, it is suitable to be selected in the pipeline that needs flow regulation
3. Due to the limitation of structure and sealing material of butterfly valve, it is not suitable for high temperature and high pressure pipeline system. The general working temperature is below 300 ¡æ and the nominal pressure is below PN40.
4. As the butterfly valve structure length is relatively short, and can be made into a large diameter, so in the case of short structure length or large diameter valve (such as more than DN 1000), butterfly valve should be selected.
5. Since the butterfly valve can be opened or closed only by 90 ¡ã rotation, it is suitable to select butterfly valve in the field with fast opening and closing requirements.
Post time: Nov-10-2020
