Do you know what Non-metallic Materials are Commonly used in Valves?
- KEPLER TEAM
- Nov 8, 2021
- 3 min read
Nitrile rubber Buna-N
The rated temperature range of nitrile rubber seat is -18℃~100℃. Usually called NBR, NITRILE, or HYCAR. It is an excellent general-purpose rubber material, suitable for water, gas, petroleum and grease, gasoline (except gasoline containing additives), alcohol and glycol, liquefied petroleum gas, propane and butane, fuel oil and many other media . It also has good abrasion resistance and deformation resistance.
The rated temperature range of food grade (FG) nitrile rubber seat is -18℃~82℃. Its composition complies with 177.2600. Section 21 of the CFR standard. The scope of application is the same as that of conventional nitrile rubber but requires FDA (U.S. Food and Drug Administration) certification.
Ethylene Propylene Rubber EPDM
The rated temperature range of ethylene-propylene rubber valve seat is -28℃~120℃. EPDM is the abbreviation of its components, namely the terpolymer of ethylene, propylene and diene, usually also called EPT, Nordell, EPR. It has excellent ozone resistance and weather resistance, good electrical insulation performance, and good resistance to polar solvents and inorganic media. Therefore, it can be widely used in HVAC industry, water, phosphate ester, alcohol, glycol, etc. Ethylene-propylene rubber seat is not recommended for use in hydrocarbon organic solvents and oils, chlorinated hydrocarbons, turpentine, or other petroleum greases.
The rated temperature range of food grade ethylene propylene rubber valve seat is -28℃~120℃. Its composition complies with 177.2600. Section 21 of the CFR standard. The scope of application is the same as that of conventional nitrile rubber but requires FDA (U.S. Food and Drug Administration) certification.
PTFE
The rated temperature range of PTFE valve seat is -32℃~200℃. Excellent high temperature resistance and chemical resistance. Because polytetrafluoroethylene has high density and excellent permeability resistance, it can also prevent the corrosion of most chemical media.
Conductive PTFE is an improved PTFE product that allows current to pass through the lining and cancels the insulation properties of PTFE. Because of its conductive properties, conductive PTFE cannot be tested by electric sparks.
Reinforced PTFE RTFE
RTFE is a modified body of PTFE material. Although the friction coefficient of pure PTFE is very low (0.02~0.04), the wear amount is very large, and because of its easy creep, poor mechanical properties, low bearing capacity, and poor dimensional stability, it has great limitations when used as a friction material. Only by modification, the special requirements of various industries for wear-resistant sealing materials can be met by the method of material composite. In terms of improving the wear resistance of PTFE, some wear-resistant materials such as glass fiber, carbon fiber, graphite, molybdenum disulfide, Bronze powder and some organic compounds make them form network nodes in the PTFE layered structure to improve stiffness, thermal conductivity, creep resistance, and greatly improve wear resistance.
Viton
The rated temperature of the fluorine rubber valve seat is -18℃~150℃. Viton is a registered trademark of DuPont, and Fluorel is a registered trademark of 3M that is equivalent to fluorine rubber. This material has high temperature resistance and excellent chemical corrosion resistance. It is suitable for hydrocarbon products, low and high concentration mineral acids, but cannot be used in steam media and water (poor water resistance).
Ultra-high molecular weight polyethylene UHMWPE
The rated temperature range of UHMWPE valve seat is -32℃~88℃. This material has better low temperature resistance than PTFE, but still has excellent chemical resistance. Ultra-high molecular weight polyethylene also has good wear resistance and corrosion resistance, and can be used in high abrasive applications.
Silicone copper rubber
Silicone copper rubber is a polymer with organic groups composed of silicon and oxygen atoms in the main chain. The rated temperature range is -100℃~300℃. It has good heat resistance and temperature resistance, excellent electrical insulation performance, and high chemical inertness. Suitable for organic acids and low-concentration inorganic acids, dilute alkalis and concentrated alkalis. The disadvantage is: low mechanical strength. Need post-vulcanization treatment.
Graphite
Graphite is a crystal of carbon, a non-metallic material, with silver gray color, soft texture, and metallic luster. Mohs hardness is 1~2, specific gravity is 2.2~2.3, and its bulk density is generally 1.5~1.8. It has unique physical and chemical properties such as high temperature resistance, oxidation resistance, corrosion resistance, thermal shock resistance, high strength, good toughness, high self-lubricating strength, high thermal conductivity, and strong electrical conductivity. It has special oxidation resistance, self-lubricity and plasticity at high temperatures, and also has good electrical conductivity, thermal conductivity and adhesion. It can be used as a filler or performance improver for rubber, plastic and various composite materials to improve the wear resistance, compression resistance or conductivity of the material. Graphite is usually used to make valve gaskets, packings and valve seats.
The melting point of graphite is extremely high. It starts to soften and tends to melt when it reaches 3000°C under vacuum. Graphite begins to evaporate and sublimate at 3600°C. The strength of general materials gradually decreases at high temperatures, while graphite is heated to 2000°C. On the contrary, the strength is doubled compared with normal temperature, but the poor oxidation resistance of graphite gradually increases with the increase of temperature.
See the Sample:KAT-Q641 Pneumatic Ball Valve Flange Connection
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