4. Classification according to working pressure
(1) Vacuum butterfly valve. Butterfly valve with working pressure lower than standard atmospheric pressure.
(2) Low pressure butterfly valve. Butterfly valve with nominal pressure PN ≤ 1.6MPa.
(3) Medium pressure butterfly valve. Butterfly valve with nominal pressure PN 2.5 〜 6.4 MPa.
(4) High pressure butterfly valve. Butterfly valve with nominal pressure PN 10.0~80.OMPa.
(5) Ultra high pressure butterfly valve. Butterfly valve with nominal pressure PN<100MPa.

Silicone tape is made of glass fiber cloth as the base cloth, and is consumed in the way of coating or calendering. It is made of high temperature resistant, anti-corrosion, high-strength glass fiber cloth, and is calendered or impregnated with silicone rubber. It is a new composite material product with high performance and multiple uses. It is suitable for low temperature - 70 to high temperature 280 degrees; It is resistant to ozone, oxygen, light and weather aging, and has excellent weather resistance for outdoor use, with a service life of up to 10 years; At the same time, it also has high insulation performance, dielectric constant 3-3.2, breakdown voltage 20-50KV/MM; Main use
1. Non metal compensator: silicone rubber cloth can be used as the flexible joint device of the pipeline, and silicone rubber coated glass fiber membrane construction data can be used as the base material of the flexible contraction joint. It can handle the damage of thermal expansion and cold contraction to the pipeline. The silicone cloth has high temperature resistance, corrosion resistance, aging resistance, good elasticity and flexibility, and can be widely used in petroleum, chemical, cement, energy and other fields.
2. Anticorrosion: silicone rubber coated with glass fiber cloth can be used as the internal and external anti-corrosion coating of pipes, which has excellent anti-corrosion performance and high strength, and is an ideal anti-corrosion material.
3. Electrical insulation: silicone cloth has a higher electrical insulation level, can accept high voltage loads, and can be made into insulating cloth, casing and other products.
4. Other categories: structural data of silicone rubber coated glass fiber membrane can be applied to building sealing data, high-temperature anti-corrosion escort tape, packaging data and other categories. Silicone cloth includes single-sided silicone tape and double-sided silicone tape, as well as high-temperature curing silicone tape and room temperature curing silicone tape. The conventional color of the silicone tape is vermilion, blue grey, black, white and other colors can also be customized.