A butterfly valve is regulating valve with simple structure that can be used for low pressure pipeline medium on-off control. A butterfly valve is a kind of valve whose closing part is a disc, which rotates around the valve shaft to open and close. Unlike a ball valve, the disc is always present within the flow, therefore a pressure drop is always induced in the flow, regardless of valve position. The valve can be used to control the flow of various types of fluids such as air, water, steam, mud, oil products, liquid metal, radioactive media and various corrosive media, mainly playing the role of cutting and throttling in the pipeline.
Butterfly valve is now in the fast development towards to high temperature, high pressure, large diameter, high sealing, excellent regulation performance, long service life direction, and has partially replaced gate valve, globe valve and ball valve. Butterfly valve, as a component used to realize on/off and flow control of pipeline system, has been widely used in petroleum, chemical industry, metallurgy, hydropower and other fields. In the known butterfly valve technology, its sealing form mostly uses the sealing structure, and the sealing material is rubber, polytetrafluoroethylene and so on. Due to the limitation of structural characteristics, it is not suitable to be used in such as high temperature situation, high pressure situation, corrosion situation and wear situation.
There is a more advanced butterfly valve that is a triple offset butterfly valve, whose body and seat are jointing components, and the sealing surface layer of the seat is covered with heat-resistant and corrosion-resistant alloy materials. Compared with the traditional butterfly valve, the triple offset butterfly valve has the advantages of high temperature resistance, light operation, no friction when it is opened and closed, and compensates the seal with the increase of the torque of the transmission mechanism when it is closed. The sealing performance and the service life of butterfly valve is improved. As a high performance valve, the triple offset butterfly valve has become the first choice in the regulating valve market with its unique structural characteristics and performance advantages.
Advantages of butterfly valve:
1. Simple in structure, small in size and light in weight.
2. Good regulating performance.
3. Less effort, small fluid resistance, operating usually, easy to open and close quickly.
4. Butterfly valve can transport mud, and the pipe post has the least liquid accumulation.
5. Under low pressure, butterfly valve has good sealing performance.
Disadvantages of butterfly valve:
1. Poor sealing.
2. Operating pressure and temperature is in a small range.