There are many types of valves, but the basic function is the same, that is, to connect or cut off the medium flow. Therefore, the sealing problem of the valve is very prominent.
To ensure that the valve can cut off the medium flow well without leakage, it is necessary to ensure that the valve seal is intact. There are many reasons for valve leakage, including unreasonable structural design, defective sealing contact surface, loose fastening parts, loose fit between valve body and bonnet, etc. All these problems may lead to poor sealing of the valve. Well, thus creating a leak problem. Therefore, valve sealing technology is an important technology related to valve performance and quality, and requires systematic and in-depth research.
The commonly used sealing materials for valves mainly include the following types:
1. NBR
Excellent oil resistance, high wear resistance, good heat resistance, strong adhesion. Its disadvantages are poor low temperature resistance, poor ozone resistance, poor electrical properties, and slightly lower elasticity.
2. EPDM
The most important feature of EPDM is its superior oxidation resistance, ozone resistance and corrosion resistance. Since EPDM belongs to the polyolefin family, it has excellent vulcanization characteristics.
3. PTFE
PTFE has strong chemical resistance, resistance to most oils and solvents (except ketones and esters), good weather resistance and ozone resistance, but poor cold resistance.
4. Cast iron
Note: Cast iron is used for water, gas and oil media with a temperature of ≤100°C and a nominal pressure of ≤1.6mpa.
5. Nickel-based alloy
Note: Nickel-based alloys are used for pipelines with a temperature of -70~150°C and an engineering pressure PN≤20.5mpa.
6. Copper alloy
Copper alloy has good wear resistance and is suitable for water and steam pipes with temperature ≤ 200 ℃ and nominal pressure PN ≤ 1.6mpa.
Post time: Dec-02-2022