Butterfly valve, also known as flap valve, is a kind of regulating valve with simple structure, and can also be used for on-off control of low-pressure pipeline medium. Butterfly valve refers to a kind of valve whose closing part (valve disc or butterfly plate) is a disc and rotates around the valve shaft to achieve opening and closing, and it mainly plays the role of cutting off and throttling 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 adjustment. Manual butterfly valve is suitable for conveying various corrosive and non-corrosive fluid medium pipelines in engineering systems such as producer, gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting and power generation and environmental protection. Interrupt the flow of the medium.
Butterfly valves are suitable for flow regulation. Because the pressure loss of the butterfly valve in the pipeline is relatively large, about three times that of the gate valve, when selecting the butterfly valve, the influence of the pipeline system by the pressure loss should be fully considered, and the firmness of the butterfly plate to withstand the pressure of the pipeline medium should also be considered when it is closed. sex. In addition, the operating temperature limitations of the elastomeric seat material at elevated temperatures must also be considered.
The structure length and overall height of the butterfly valve are small, the opening and closing speed is fast, and it has good fluid control characteristics. The structure principle of the butterfly valve is most suitable for making large-diameter valves. 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 the butterfly valve so that it can work properly and effectively. Usually, in throttling, regulating control and mud medium, short structure length and fast opening and closing speed are required. Low pressure cut-off (small differential pressure), butterfly valve is recommended.
(1) The centerline butterfly valve is suitable for fresh water, sewage, seawater, salt water, steam, natural gas, food, medicine, oil that require complete sealing, zero leakage in gas test, high life expectancy, and working temperature of -10℃~150℃ Products and various acid-base and other pipelines.
(2) The soft-sealed eccentric butterfly valve is suitable for the two-way opening and closing and adjustment of ventilation and dust removal pipelines, and is widely used in gas pipelines and waterways of metallurgy, light industry, electric power, and petrochemical systems.
(3) Metal-to-metal wire sealed double eccentric butterfly valve is suitable for urban heating, gas supply, water supply and gas, oil, acid-base and other pipelines, as a regulating and intercepting device.
(4) In addition to being used as a program control valve for a large-scale pressure swing adsorption gas separation device, the metal-to-metal surface sealing triple eccentric butterfly valve can also be widely used in petroleum, petrochemical, chemical, metallurgy, electric power and other fields. Good alternative.
(1) Compared with the gate valve, the butterfly valve has a relatively large pressure loss, so it is suitable for pipeline systems where the pressure loss requirements are not strict.
(2) Since the butterfly valve can be adjusted by flow, it is easy to choose in the pipeline that needs to be adjusted.
(3) The structure of the butterfly valve and the limitation of the sealing material are not suitable for high temperature and high pressure piping systems. The general working temperature is below 300℃, and the nominal pressure is below PN40.
(4) Since the structure length of the butterfly valve is relatively short, and it can be made into a large diameter, the butterfly valve should be selected in the occasions where the structure length is short or the valve with large diameter.
(5) Since the butterfly valve can be opened or closed only by rotating 90°, the butterfly valve should be selected when the opening and closing requirements are fast.