Butterfly valves are of various types and have obvious advantages. It can withstand high temperature, wide range of pressure, large nominal diameter of valve, strong self-cleaning ability, and the valve body is made of carbon steel, and the sealing ring material of valve plate has many options. It is often used for the flow of air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive medium. It is mainly used for cutting off and throttling on the pipeline. Today, we will classify butterfly valves in many ways.
1、 Divided by driving mode
(1) Electric butterfly valve
(2) Pneumatic butterfly valve
(3) Hydraulic butterfly valve
(4) Manual butterfly valve
2、 According to the structure form:
(1) Central seal butterfly valve
(2) Single eccentric seal butterfly valve
(3) Double eccentric sealing butterfly valve
(4) Three eccentric seal butterfly valve
3、 Material of sealing surface:
(1) Soft seal butterfly valve.
1. the sealing pair is composed of non-metallic soft material to non-metallic soft material
2. the sealing pair is composed of hard metal materials to non-metallic soft materials
(2) Metal hard sealed butterfly valve.
The sealing pair is composed of hard metal material to metal hard material
4、 According to the sealing form:
(1) Forced seal butterfly valve.
1. elastic sealing butterfly valve: the specific pressure of sealing is generated by the elasticity of valve plate pressing the valve seat when the valve is closed, and the valve seat or valve plate is elastic.
2. external torque seal butterfly valve: the specific pressure of the seal is generated by the torque applied to the valve shaft.
(2) Filling seal butterfly valve: the specific pressure of sealing is generated by charging the spring seal element on the valve seat or valve plate.
(3) Automatic sealing butterfly valve: the specific pressure of sealing is generated automatically by medium pressure.
4、 According to working pressure:
(1) Vacuum butterfly valve. Butterfly valve with working pressure lower than atmospheric pressure of the stack.
(2) Low pressure butterfly valve. Butterfly valve with nominal pressure PN < 1.6Mpa.
(3) Medium pressure butterfly valve. Butterfly valve with nominal pressure PN of 2.5-6.4mpa.
(4) High pressure butterfly valve. Butterfly valve with nominal pressure PN of 10.0-80.0mpa.
(5) Ultra high pressure butterfly valve. Butterfly valve with nominal pressure PN > 100MPa.
5、 According to the working temperature:
(1) High temperature. t> 450 ° C butterfly valve.
(2) Medium temperature butterfly valve. The butterfly valve with 120 C < T < 450 ℃.
(3) Normal temperature butterfly valve. One butterfly valve with 40C < T < 120 ° C.
(4) Low temperature butterfly valve. One butterfly valve with 100 < T < 40 ° C.
(5) Ultra low temperature butterfly valve. T < a butterfly valve at 100 ° C.
6、 According to the connection mode:
1. Wafer butterfly valve
Butterfly plate of the clamp butterfly valve is installed in diameter direction of the pipe. The valve is fully open.
The structure of the wafer butterfly valve is simple, the volume is small and the weight is light. Butterfly valve has two sealing types: elastic seal and metal seal. Elastic sealing valve, sealing ring can be embedded on the valve body or attached to the butterfly plate.
2. Flange butterfly valve
Flange butterfly valve is vertical plate structure, and the valve stem is a integral metal hard seal valve. The sealing ring of the valve is a composite structure of flexible graphite plate and stainless steel plate, which is installed on the valve body, and the sealing surface of butterfly plate is overlaid with stainless steel. The sealing ring of soft sealing valve is made of NBR, which is installed on butterfly plate.
3. Lug butterfly valve
4. Welded butterfly valve
Welding butterfly valve is a kind of airtight butterfly valve, which is widely used in the pipeline with medium temperature ≤ 300 ℃ and nominal pressure of 0.1MPa in the production process of building materials, metallurgy, mine and power, so as to connect, open and close or adjust the medium quality.