The material selection of the valve seal ring depends on the specific application scenario and requirements. The following are some common valve sealing ring materials and their characteristics:
Synthetic rubber: has good oil resistance, temperature resistance, corrosion resistance, suitable for nominal pressure PN≤1MPa globe valve, gate valve, diaphragm valve, butterfly valve, check valve, pinch valve and so on. However, rubber seals are easy to age at high temperatures, affecting their service life, and have poor adaptability to highly corrosive fluids.
Nylon: with low friction coefficient and good corrosion resistance, suitable for temperature t≤90℃, nominal pressure PN≤32MPa ball valve, globe valve, etc. However, nylon is poorly adapted to high temperature and high pressure environments.
Polytetrafluoroethylene (PTFE) : has excellent high temperature resistance and corrosion resistance, suitable for temperature t≤232℃, nominal pressure PN≤6.4MPa globe valve, gate valve, ball valve, etc. However, the cost of PTFE sealing rings is higher, and it is easy to embrittlement at low temperatures.
Silicone: has good weather resistance and anti-aging properties, long service life. However, the cost of silicone sealing rings is higher, and the adaptability to highly corrosive fluids is also poor.
In addition to the above common materials, there are cast iron, babbitt, copper alloy, chromium stainless steel and chromium nickel titanium stainless steel and other materials are also commonly used in valve sealing rings. Cast iron is suitable for gas and oil gate valves, globe valves, plug valves, etc. with temperature t≤100℃ and nominal pressure PN≤1.6MPa; Babbitt alloy is used for ammonia stop valves with temperature t-70~150℃ and nominal pressure PN≤2.5MPa; Chromium stainless steel and chromium nickel titanium stainless steel have better corrosion resistance.
In general, the material selection of the valve sealing ring needs to be comprehensively considered according to the specific application scenarios and requirements. In the selection, need to consider the nature of the medium, temperature, pressure, sealing requirements and cost and other factors.