What are the main types of butterfly valves?

Butterfly valve, also known as flap valve, is a simple control valve. Butterfly valve, which can be used to control the opening and closing of low-pressure pipeline medium, refers to a valve whose closing part (disc or butterfly plate) is a disc and rotates around the valve shaft to realize opening and closing. The valve can be used to control the flow of various types of fluids, such as air, water, steam, corrosive media, mud, oil, liquid metal and radioactive media. It mainly cuts off and throttles the pipeline.

Main classification

1, by driving mode

(1) electric butterfly valve

(2) Pneumatic butterfly valve

(3) Hydraulic butterfly valve

(4) Manual butterfly

2, according to the structural form:

(1) butterfly valve with center seal

(2) Single eccentric sealing butterfly valve

(3) Double eccentric sealing butterfly valve

(4) Three-eccentric sealing butterfly valve

3. Key points of sealing surface materials:

(1) Soft sealing butterfly valve.

1) The sealing pair consists of nonmetallic soft materials and nonmetallic soft materials.

2) The sealing pair consists of metal hard materials and nonmetal soft materials.

(2) Metal hard seal butterfly valve. The sealing pair consists of metal hard material and metal hard material.

4. According to the sealing form:

(1) Forced sealing butterfly valve.

1) butterfly valve with elastic seal. The sealing specific pressure is produced by the elasticity of the valve plate pressing against the valve seat, valve seat or valve plate when the valve is 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 sealing specific pressure is generated by the pressurization of the elastic sealing element on the valve seat or valve plate.

(3) Automatic sealing butterfly valve. The seal specific pressure is automatically generated by the medium pressure.

5, according to the working pressure:

(1) vacuum butterfly valve. Butterfly valve with working pressure lower than atmospheric pressure of standard reactor.

(2) Low pressure butterfly valve. Nominal pressure pn

(3) Medium pressure butterfly valve. Butterfly valve with nominal pressure PN of 2.5-6.4 MPa.

(4) High pressure butterfly valve. The nominal pressure PN is 10. 0-80.0 MPa butterfly valve.

(5) Ultra-high pressure butterfly valve. Nominal pressure PN> 100MPa butterfly valve.

6, according to the working temperature:

(1) high temperature. Butterfly valve at t & gt450°c

(2) Medium temperature butterfly valve. 120C & lt； Butterfly valve at t & lt450℃.

(3) Normal temperature butterfly valve. 1.40c < t<120 c butterfly valve

(4) Low temperature butterfly valve. One piece 100

(5) ultra-low temperature butterfly valve. T< 100℃ butterfly valve

7. According to the connection mode:

1, wafer butterfly valve

The butterfly plate of the wafer butterfly valve is installed in the diameter direction of the pipeline. The valve is fully open.

This butterfly valve is simple in structure, small in size and light in weight. Butterfly valves have two sealing forms: elastic seal and metal seal. Elastic sealing valve, the sealing ring can be embedded in the valve body or attached to the periphery of the butterfly plate.

2. Flange butterfly valve

Flange butterfly valve is vertical plate structure, and the valve stem is the sealing ring of integral metal hard sealing valve.

It is a composite structure of flexible graphite plate and stainless steel plate, which is installed on the valve body, and stainless steel is surfacing on the sealing surface of butterfly plate. The sealing ring of the soft sealing valve is made of nitrile rubber and installed on the butterfly plate.

3. Lug butterfly valve

4. Welding butterfly valve

Welding butterfly valve is a kind of unsealed butterfly valve, which is widely used in pipelines with medium temperature ≤300℃ and nominal pressure of 0. 1Mpa in the production process of building materials, metallurgy, mining and electric power. , to connect, open and close or adjust the media quality.