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 the butterfly valve so that it can work properly and effectively.

Generally, in throttling and regulating control and mud medium, short structure length and fast opening and closing speed (1 / 4 turn) are required. Low pressure cut-off valve (small differential pressure), butterfly valve is recommended.

Butterfly valve can be selected in case of double position regulation, necked ground channel, low noise, cavitation and gasification, small leakage to the atmosphere and abrasive medium.

When the butterfly valve is used under special working conditions, such as throttling regulation, strict sealing requirements, or severe 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 requiring complete sealing, zero gas test leakage, high service life and working temperature of – 10 ℃ ~ 150 ℃.

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 sealed double eccentric butterfly valve is suitable for urban heating, gas supply, water supply and other gas, oil, acid-base and other pipelines as a regulating and throttling device.