Butterfly valves can be divided into offset plate type, vertical plate type, inclined plate type and lever type according to the structure. According to the sealing form, it is divided into two types: relatively sealed type and hard sealed type. Soft seal butterfly valves generally use rubber ring seals, and hard seal butterfly valves generally use metal ring seals. According to the connection type, it is divided into flange connection and wafer connection. According to the transmission mode, it is divided into manual, gear transmission, pneumatic, hydraulic and electric. 

For a wide variety of butterfly valves, and in special working conditions, the corresponding butterfly valve products are also different, so for this kind of valve, you should choose the type separately from the engineer! According to common types and classifications, butterfly valves can be divided into the following forms:

(1) Classified by structure

1. Center sealing butterfly valve

2. Single eccentric sealing butterfly valve

3. Double eccentric sealing butterfly valve

4. Triple eccentric sealing butterfly valve

(2) Classified by link

1. Wafer butterfly valve

2. Flange butterfly valve

3. Lug butterfly valve

4. Welded butterfly valve

(3) Classified by working temperature

1. High temperature butterfly valve

2. Medium temperature butterfly valve

3. Normal temperature butterfly valve.

4. Low temperature butterfly valve.

(4) Classified by sealing surface material

1. Soft sealing 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 metallic hard materials and non-metallic soft materials.

2. Metal hard sealing butterfly valve. The sealing pair is composed of a metal hard material to a metal hard material.

(5) Classified by work pressure

1. Vacuum butterfly valve, a butterfly valve whose working pressure is lower than the atmospheric pressure of the standard stack.

2. Low pressure butterfly valve, butterfly valve with nominal pressure 1.6MPa.

3. Medium pressure butterfly valve, butterfly valve with nominal pressure PN of 2.5-6. 4MPa.

4. High-pressure butterfly valve, the butterfly valve whose nominal pressure PN is 10.0-80.0MPa.

5. Ultra-high pressure butterfly valve, butterfly valve with nominal pressure PN>100MPa.

(6) Classified by sealing form

1. Forced sealing butterfly valve.

(1) Elastic sealing butterfly valve. The specific pressure of the seal is generated by the elasticity of the valve seat or the valve plate when the valve plate squeezes the valve seat when closed.

(2) External torque sealing butterfly valve. The seal specific pressure is generated by the torque applied to the valve shaft.

2. Pressurized sealing butterfly valve. The specific sealing pressure is generated by the pressure of the elastic sealing element on the valve seat or valve plate.