Butterfly valve, also called flap valve, is a simple-structured conditioning valve, which can also be used for switching control of low-pressure pipeline media. Butterfly valve is a kind of valve in which the closing part (disc or butterfly plate) is a disc, which rotates around the valve shaft to reach the opening and closing. It mainly cuts off and saves on the pipeline. The butterfly valve opening and closing part is a disc-shaped butterfly plate, which rotates around its own axis in the valve body to achieve the purpose of opening and closing or conditioning. Butterfly valves are suitable for pipelines transporting various corrosive and non-corrosive fluid media in engineering systems such as generators, coal gas, natural gas, liquefied petroleum gas, city gas, cold and hot air, chemical smelting and power generation environmental protection, for conditioning and cutting The activity of the medium.
Application occasions of butterfly valve:
Butterfly valves are suitable for flow regulation. Because the pressure loss of the butterfly valve in the pipeline is relatively large, it is about three times that of the gate valve. Therefore, when selecting the butterfly valve, the influence of the pressure loss on the pipeline system should be fully considered, and the consolidation of the butterfly plate with the pressure of the pipeline medium should also be considered when closing. Sex. In addition, it is necessary to consider the constraints of the operating temperature of the elastic valve seat material at high temperatures.
The structural length and overall height of the butterfly valve are small, the opening and closing speed is fast, and it has outstanding fluid control characteristics. The structural principle of the butterfly valve is most suitable for manufacturing large-diameter valves. When the butterfly valve is required to control the flow rate, the most important thing is to correctly select the size and type of the butterfly valve so that it can operate properly and effectively.
Generally, in saving, conditioning and controlling 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.
In two-position conditioning, narrowed passages, low noise, cavitation and vaporization, a small amount of leakage to the atmosphere, and abrasive media, butterfly valves can be used.
Save conditioning under special working conditions, or require strict sealing, or severe wear, low temperature (cryogenic) and other working conditions when using butterfly valves, you need to use a specially designed metal seal to adjust the triple or double migraine of the equipment Dedicated butterfly valve.
The centerline butterfly valve is suitable for fresh water, sewage, sea water, salt water, steam, natural gas, food, medicine, oil and various products that require complete sealing, zero gas test leakage, high life requirements, and operating temperature of -10~150℃ Acid-base and other pipelines.
The soft sealing butterfly valve is suitable for the two-way opening and closing and adjustment of ventilation and dust removal pipelines. It is widely used in gas pipelines and waterways in metallurgy, light industry, electric power, and petrochemical systems.
The metal-to-metal wire sealing double migraine butterfly valve is suitable for urban heating, steam, water and gas, oil, acid and alkali pipelines, as a conditioning and interception device.
In addition to being used as a large-scale pressure swing adsorption (PSA) gas separation equipment program control valve, the metal-to-metal sealing triple-partial butterfly valve can also be widely used in petroleum, petrochemical, chemical, metallurgical, electric power and other fields, such as gate valves, stop valves, etc. Outstanding replacement product.
Selection principle of butterfly valve:
1. Because the butterfly valve has a relatively large pressure loss compared to the gate valve, it is suitable for the pipeline system with less strict pressure loss requirements
2. Because the butterfly valve can be used for flow adjustment, it is suitable for use in pipelines that require flow adjustment.
3. Because of the restriction of the structure and sealing materials of the butterfly valve, it is not suitable for high temperature and high pressure pipeline system. Generally, the operating temperature is below 300℃, and the nominal pressure is below PN40.
4. Because the structure length of the butterfly valve is relatively short and it can be made into a large diameter, the butterfly valve should be used in the occasions where the structure length is short or the large diameter valve (such as DN1000 or more).
5. Because the butterfly valve can be opened or closed by only rotating 90°, the butterfly valve should be used in the occasions requiring fast opening and closing.
