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What does valve commonly use nonmetal material to have?

2021-05-18 11:03


       Nitrile rubber

  NBR seat rated temperature range-18 °C ~ 100 °C. It is an excellent general-purpose rubber material suitable for water, gas, oil and grease, gasoline (other than gasoline with additives) , alcohol and ethylene glycol, Liquefied petroleum gas, propane and butane, fuel oil and many other media. At the same time, it also has good wear resistance and deformation resistance.

  Food Grade (FG) NBR valve seat rated temperature range-18 °C ~ 82 °C. Its composition conforms to CFR standard part 21177.2600. Stanza. It is used for the same range of applications as conventional nitrile rubber but requires FDA approval.

       Ethylene propylene rubber

  Ethylene propylene rubber seats are rated at temperatures ranging from-28 °C to 120 °C. EPDM is the abbreviation of its composition, namely ethylene, propylene and Diene Terpolymer, ozone resistance and weather resistance excellent, good electrical insulation performance, resistance to polar and inorganic media good. Therefore, it can be widely used in HVAC industry, water, phosphate Ester, alcohol, ethylene glycol and so on. Ethylene propylene rubber seats are not recommended for use in hydrocarbon solvents and oils, chlorinated hydrocarbons, Turpentine, or other petroleum oils and fats.

  Food Grade Ethylene propylene rubber seats are rated at temperatures ranging from-28 °C to 120 °C. Its composition conforms to CFR standard part 21177.2600. Stanza. It is used for the same range of applications as conventional nitrile rubber but requires FDA approval.


  Polytetrafluoroethylene seats are rated at temperatures ranging from-32 °C to 200 °C. Excellent resistance to high temperature and chemical corrosion. Polytetrafluoroethylene is highly dense, impermeable, and resistant to corrosion in most chemical media.

  The conductive polytetrafluoroethylene is an improved polytetrafluoroethylene that allows current to pass through the lining and thereby negate the insulating properties of the polytetrafluoroethylene. Because of its conductive properties, conductive polytetrafluoroethylene can not be used to test its quality.

      Enhanced polytetrafluoroethylene

   RTFE is a modified body of PTFE material. Although pure PTFE has a low friction coefficient (0.02 ~ 0.04) , it has a great amount of wear, and it is limited to be used as a friction material because of its easy creep, poor mechanical properties, low bearing capacity and poor dimensional stability. Only modification, through the method of composite materials to meet all walks of life to wear-resistant sealing materials put forward special requirements, in improving the wear resistance of PTFE, it can be mixed with wear resistant materials such as fiberglass, carbon fiber, graphite, molybdenum disulfide, bronze powder, and some organic compounds, it makes them form network node in PTFE layer structure, which improves stiffness, thermal conductivity, creep resistance and wear resistance.


    The rated temperature of fluorine rubber valve seat is-18 °C ~ 150 °C. Viton is the trademark of DuPont, and fluorine is the trademark of 3M. This material has high temperature resistance and excellent anti-chemical corrosion. Suitable for hydrocarbon products, low concentration and high concentration mineral acids, but can not be used in steam medium and water (poor water resistance) .

        Ultrahigh molecular weight polyethylene

   Uhmwpe seat rated temperature ranges from-32 °C to 88 °C. The 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, can be used in high wear occasions.

       Silicon copper rubber

  Silicon-copper rubber is a polymer with organic groups and the main chain is composed of silicon and oxygen atoms. Rated temperature ranges from-100 °C to 300 °C. With good heat resistance and temperature resistance, excellent electrical insulation, chemical inertness. Suitable for organic acid and low concentration of inorganic acid, dilute alkali and concentrated Alkali. DISADVANTAGES: Low Mechanical Strength. It needs post-curing.


  Graphite is the crystal of carbon, is a non-metallic material, silver gray color, soft, with a metallic luster. The MOHS hardness is 1 ~ 2, the specific gravity is 2.2 ~ 2.3, and the bulk density is 1.5 ~ 1.8. With high temperature, oxidation resistance, corrosion resistance, thermal shock resistance, strength, toughness, self-lubricating high strength, thermal conductivity, strong conductivity and other unique physical and chemical properties. It has special oxidation resistance, self-lubrication and plasticity at high temperature, and has good conductivity, heat conduction and adhesion. It can be used as filler or performance improver of rubber, plastic and various composite materials to improve their wear resistance, compression resistance or conductivity. Graphite is usually used to make the sealing gasket, packing and seat of the valve.

     The melting point of graphite is very high, the melting point of graphite begins to soften when the temperature reaches 3000 °C in vacuum, the graphite begins to evaporate and sublimate when the temperature reaches 3600 °c, the strength of general materials gradually decreases when the temperature reaches 2000 °C, the strength of graphite is twice as high as that at normal temperature, but the oxidation resistance of graphite increases with the increase of temperature.

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