The common rotor materials used in lobe pumps are metal rotors and rubber rotors, users can choose the appropriate rotor according to the different materials they convey, the following Ace will introduce the difference between the two.
I. Metal rotors
Metal rotor production cost is relatively low, but for some special media difficult to handle, not suitable for oil fields, printing and dyeing industry and other harsh working conditions, metal rotor and pump chamber between the non-contact, which caused the pump's poor self-priming ability, leakage, volumetric efficiency is relatively low, but also limit the pump outlet pressure.
Common metal rotors are stainless steel 304, stainless steel 316L, QT450, copper, and duplex steel.
1, 304 is generally used in food, or the presence of particulate matter in the medium, and corrosive media. (Used more often).
2, stainless steel 316L has good corrosion resistance to oxidizing acids, dilute alkaline liquids, most organic acids, inorganic salts, atmospheric and water vapour, etc.
3、Copper is generally used in chemical flammable and explosive media with better resilience.
4, duplex steel stress corrosion damage resistance, with high strength, high resistance to chloride local corrosion stress corrosion, generally on the petrochemical industry, oil and gas harsh environment, the price is higher than the metal rotor.
II. Rubber rotor
The rubber rotor makes full use of the high elasticity and good expansion of rubber. The rubber rotor can be used with the pump chamber to achieve interference, which greatly improves the self-priming capacity and volumetric efficiency of the pump. The rubber lobe pump is recommended for use in conditions requiring high self-priming capacity.
Commonly available rubber rotors are NBR, Viton, EPDM and perfluoroelastomer.
1、Nitrile rubber is generally used for clear water, domestic sewage and other simple media transport, oil and wear resistance is very good
2、Ethylene-Propylene rubber is more suitable for transporting alcohols, cleaning agents, etc.
3、Fluoroelastomer is generally used in chemical media, crude oil, seawater and more complex environments.
4. Perfluorinated ethers are very expensive, but have relatively excellent resistance to chemical media.