Butterfly valve, also known as flap valve, is a simple structure of the regulating valve, can be used for low-pressure pipe medium switching control. The opening and closing of the butterfly valve is called the butterfly plate, and it takes a disk shape to rotate around the valve stem to open and close.
Butterfly valve can be divided into flange type butterfly valve and wafer type butterfly valve according to the different types of connection; according to the structure, it can be divided into middle line butterfly valve and eccentric butterfly valve. The structure of the butterfly valve is very simple. It consists of a valve body, a valve stem, a valve seat, a butterfly plate and a transmission mechanism. The common transmission methods include a handle, a turbine, a pneumatic and an electric motor. Let's do a parsing of the butterfly valve for the structural diagram of the butterfly valve.
1. The valve body is the support of the entire butterfly valve. Several common materials according to performance from left to right are, gray cast iron, ductile iron, cast steel, stainless steel. Among them, the performance of the butterfly valve made of gray cast iron is the most common, and the performance of the stainless steel butterfly valve is the best.
2. Inside the valve body, the valve stem is connected with the transmission device and butterfly plate of the butterfly valve, and the valve stem is driven by the driving transmission device. The valve stem is rotated with the butterfly plate to realize the opening and closing of the butterfly valve. The stem material is usually stainless steel.
3. The valve seat, like the butterfly plate, is the part that directly contacts the media inside the pipe, and is also subject to the scouring and corrosion of the medium. The butterfly valve can be divided into soft sealing butterfly valve and metal hard sealing butterfly valve according to different valve seats. The soft seat butterfly valve uses the most valve seat material with EPDM, nitrile and PTFE, and has good sealing performance. Zero leakage. The valve seat of the metal hard seal butterfly valve is usually made of metal and can be better applied in high temperature and high pressure environments. There are two kinds of disc material most common, ductile iron and stainless steel, we have already mentioned several materials commonly used in the valve body, on the same butterfly valve, the material properties of the butterfly plate should be at least higher than the valve body material. One grade.
4. The butterfly valve transmission has been introduced above, handle, turbine, pneumatic, electric four most common driving methods. Among them, the handle butterfly valve and the turbine butterfly valve need people to operate, which is also called a manual butterfly valve. Pneumatic butterfly valves and electric butterfly valves are automatic valves.