What materials are suitable for screw pump stator & rotor for Sewage sludge /Wastewater ?

The material selection of screw pump stator and rotor must match the conveyed medium properties, solid content, temperature and corrosiveness, following the core principle of “stator resists medium corrosion/wear, rotor resists erosion/corrosion”. The specific selection steps are as follows:

1. Clarify Medium & Working Condition Parameters

First confirm 3 core indicators: medium type (slurry/crude oil/chemical slurry, etc.), sand content (＜10%/≥10%), pH value (neutral/weak acid-alkali/strong acid-alkali), temperature (≤80℃/＞80℃).

2. Stator Material Selection (Rubber-Based)

-Neutral, non-corrosive or Weak acid-alkali,sand content ＜10% → Nitrile Butadiene Rubber (NBR);Features: Wear-resistant, oil-resistant, high cost-effectiveness, suitable for suitable for conventional slurry ,oil-associated slurry, general Sewage sludge/wastewater transfer ,mining and river dredging,

— Weak acid-alkali, high water content → Ethylene Propylene Diene Monomer (EPDM); suitable for municipal sludge, weak acid-alkali wastewaters/ewage treatment,(But not tolerant of oil)

– Low-to-medium concentration acid-alkali + high sand content → Hydrogenated Nitrile Butadiene Rubber (HNBR); suitable for mining mild corrosive pulp

– Strong acid-alkali, high temperature (≤180℃) → Fluororubber (FKM); suitable for concentrated acid slurry, chemical corrosive paste

– High sand content (≥10%) wear-resistant conditions → Wear-resistant rubber; suitable for river dredging, mining high-sand pulp,

3. Rotor Material Selection (Metal-Based)

– Neutral, non-corrosive, conventional conditions → Quenched 45# Steel / 304 Stainless Steel; low cost, easy to process

– Weak acid-alkali, sand content ＜10% → 316L Stainless Steel; resistant to mild corrosion, suitable for chemical wastewater

– Medium-strong acid, high sand content erosion conditions → 2205/2507 Duplex Stainless Steel; resistant to pitting and erosion

– Ultra-high sand content, severe wear conditions → Tungsten Carbide Coated Rotor; high surface hardness, 3-5 times longer service life than ordinary metal

#Netzsch pump #Seepex pump #screw pump #Progressive Cavity Pump #stator #rotor #Sewage sludge #Wastewater treatment