The followings are the materials used for liner of valves for corrosion resistance.
1. PTFE (F4)
Applicable media: strong acid, strong base, strong oxidant, etc;
Operating temperature: -200～180℃;
Features: having excellent chemical stability, high heat resistance and low temperature resistance; the material is also excellent self-lubricating materials while having lower mechanical property, poor mobility and high thermal expansion.
2. FEP (F46)
Applicable media: all of organic solvents or reagents, dilute or strong mineral acids, alkalis, ketones, aromatic hydrocarbons, chlorinated hydrocarbons;
Operating temperature: -85～150℃;
Features: mechanical properties, electrical properties and chemical stability are the same as those of F4. The prominent advantages are that it has high impact toughness, excellent weather resistance and radioactivity.
3. PCTEF (F3)
Applicable media: all of organic solvents, inorganic corrosive liquids (oxidizing acids);
Operating temperature: -195～120℃;
Features: heat resistance, electrical properties and chemical stability is only next to F4. Mechanical strength, creep properties and hardness are better than F4.
4. PVDF (F2)
Applicable media: most of chemicals and solvents;
Operating temperature: -70～100℃;
Features: tensile strength and compression strength; having resistance to bend, weather resistance, radiation resistance, light resistance and aging resistance. The largest advantage is that the material has good toughness, easy for molding.
5. RPP
Applicable media: aqueous solutions of inorganic salt, weak or strong solutions of inorganic acids and alkalis;
Operating temperature: -14～80℃;
Features: one of plastics having the lightest weight; yield strength, tensile strength, compression strength and hardness better than low pressure polyethylene, having good rigidity and good heat resistance, easy for molding. Impact toughness, mobility and modulus of bending elasticity are highly improved after changing properties.
6. PO
Applicable media: acids, alkali and salts with different concentrations and some organic solvents;
Operating temperature: -58～80℃
Features: it is the most ideal anticorrosive material, having already widely applied in rotational molded equipment and liner of pipes.
7. PVC
Applicable media: resistance to water, concentrated alkalis, non-oxidizing acids, chain hydrocarbons, oil and ozone;
Applicable temperature: 0～55℃;
Features: having higher mechanical strength, good chemical stability, dielectric property, oil resistance and aging resistance, easy for welding and bonding, having lower price.
For different types of lining valves, the nominal diameter of shell is the same as connection dimension. According to different media, different materials can be used for liner: modified PO, RPP, F46, F4, F3, F2.
