Butterfly valve, also known as flap valve, is a simple regulating valve. At the same time, it can also be used for switching control of low-pressure pipeline medium. Butterfly valve refers to a valve whose closing part (disc or disc) is a disc and rotates around the valve shaft to open and close. It mainly plays the role of cut-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, closing or adjustment. Butterfly valve is applicable to pipelines conveying various corrosive and non corrosive fluid media in engineering systems such as generator, gas, natural gas, liquefied petroleum gas, urban gas, hot and cold air, chemical smelting, power generation and environmental protection, and is used to regulate and cut off the flow of media.
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 that of gate valve, when selecting butterfly valve, the influence of pressure loss on pipeline system should be fully considered, and the firmness of butterfly plate bearing pipeline medium pressure when closing should also be considered. In addition, the working temperature limit of elastic seat material at high temperature must be considered.
The butterfly valve has small structural length and overall height, fast opening and closing speed, and 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 control flow, 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, regulation and control and mud medium, short structure length and fast opening and closing speed (1 / 4R) are required. Low pressure cut-off valve (small differential pressure), butterfly valve is recommended.
Butterfly valve can be used in the channel with double position regulation and necking, low noise, cavitation and gasification, 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 or serious wear, low temperature (cryogenic) and other working conditions, it is necessary to use the special three eccentric or double eccentric butterfly valve with specially designed metal seal and regulating device.
The midline butterfly valve is applicable to fresh water, sewage, seawater, brine, steam, natural gas, food, medicine, oil products, various acid and alkali and other pipelines that require complete sealing, zero gas test leakage, high service life and working temperature of – 10 ~ 150 ¡æ.
Soft seal eccentric butterfly valve is suitable for two-way opening, closing and adjustment of ventilation and dust removal pipeline. It is widely used in gas pipeline and water channel of metallurgy, light industry, electric power and petrochemical system.
Metal to metal wire sealed double eccentric butterfly valve is suitable for urban heat supply, steam supply, water supply, gas, oil, acid and alkali and other pipelines as regulating and intercepting devices.
In addition to being used as the program control valve of large pressure swing adsorption (PSA) gas separation unit, the metal to metal sealed triple eccentric butterfly valve can also be 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. Because the pressure loss of the butterfly valve is relatively large compared with the gate valve, it is suitable for the pipeline system with lax pressure loss requirements
2. Since the butterfly valve can be adjusted by flow, it is suitable for selection in the pipeline requiring flow adjustment
3. Due to the limitation of butterfly valve structure and sealing materials, 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. Since the butterfly valve has a short structural length and can be made into a large diameter, it should be selected for occasions where the structural length is required to be short or for large diameter valves (such as above DN1000).
5. Since the butterfly valve can be opened or closed only by rotating 90 ¡ã, it is appropriate to select the butterfly valve in the field with fast opening and closing requirements.
Post time: Jan-13-2022
