Stainless Steel Centrifugal Sewage Pump

I. Product Overview

Stainless steel centrifugal sewage pumps are designed based on the centrifugal force transportation principle, using austenitic stainless steel (304/316) or duplex stainless steel. They provide efficient sewage discharge solutions for municipal sewage, industrial wastewater, and building drainage. The stainless steel material system, combined with anti-clogging structural design, integrates excellent sewage corrosion resistance, impurity wear resistance, and large-particle passage capability, enabling stable operation in sewage containing solid particles, fibrous impurities, and acid-base media. It meets the requirements of GB/T 24674-2009 Submersible Electromagnetic Pumps for Sewage and Wastewater and environmental protection discharge standards.

II. Core Materials and Characteristics

1.Austenitic Stainless Steel (304/304L)

Characteristics: Contains 18% chromium and 8% nickel, tensile strength ≥520MPa, resistant to general domestic sewage corrosion (pH6-9), and has better chloride ion (Cl⁻≤500ppm) resistance than cast iron, but is prone to pitting corrosion in sewage containing sulfide (S²⁻).

Applications: Manufactures components such as pump bodies and impellers, suitable for municipal domestic sewage and building drainage systems (water temperature ≤60℃).

2.Austenitic Stainless Steel (316/316L)

Characteristics: Added with molybdenum (2-3%), chloride ion corrosion resistance is 5-8 times higher than 304 (resists Cl⁻≤20000ppm), outstanding acid-base resistance (pH4-12), and strong resistance to grease adhesion in sewage.

Applications: Used for industrial wastewater treatment (e.g., food processing, paper mill wastewater), resisting corrosion from acid, alkali, or mildly oily sewage.

3.Duplex Stainless Steel (2205)

Characteristics: Ferritic-austenitic duplex structure, tensile strength ≥620MPa, pitting corrosion resistance index (PREN) ≥32, 30% improved wear resistance to solid particles in sewage compared to 316 stainless steel, and can withstand bubble collapse impact below 300MPa (excellent cavitation resistance).

Applications: Suitable for highly corrosive industrial sewage (e.g., chemical wastewater, electroplating solution) or harsh sewage discharge scenarios with sediment content ≤1% and fibrous impurities ≥5%.

III. Technical Advantages and Limitations

1.Core Advantages

Excellent Corrosion Resistance and Anti-Clogging Ability

The corrosion rate of 316 stainless steel impellers in chloride-containing sewage is <0.01mm/year, with a service life 8-10 times longer than cast iron impellers. The pump body adopts a large-channel impeller design (flow channel width ≥40mm), capable of passing solid particles with diameter ≤20mm, combined with serrated blades to cut fibrous impurities and reduce entanglement risks.

High-Efficiency Sewage Discharge and Reliability

The hydraulic efficiency of duplex stainless steel impellers under 0.6MPa pressure reaches 85%-90%, 12%-15% higher than cast iron sewage pumps, with pressure pulsation ≤±0.06MPa, ensuring rapid sewage emptying (e.g., 1000m³ sewage discharge time is 25% shorter than cast iron pumps).

Low Maintenance and Environmental Design

The smooth stainless steel surface is less prone to scaling, with maintenance costs 70% lower than cast iron sewage pumps (cast iron requires regular rust removal and anti-corrosion treatment, increasing costs by 30%). Adopts mechanical seal + silicon carbide friction pair, with sewage leakage ≤10 drops/minute, complying with environmental protection discharge standards.

2.Main Limitations

Cost and Weight Constraints

Stainless steel materials cost 2-3 times more than cast iron (e.g., 316 stainless steel sewage pumps cost about 2.8 times that of cast iron pumps), and the density of 7.9g/cm³ is 2.8 times higher than aluminum alloy, increasing the weight of the same diameter pump by 15-20kg, requiring reinforced supports during installation.

High-Temperature and Impurity Working Condition Limitations

The corrosion resistance of 316 stainless steel pumps decreases by 15% at water temperatures >80℃, requiring a cooling system. Although duplex stainless steel pumps can withstand 120℃, in sewage with hard particles (such as sand) >1.5%, the impeller wear rate increases to 0.025mm per thousand hours, requiring a pre-filter.

Energy Efficiency and Environmental Balance

Although the hydraulic efficiency of stainless steel pumps is higher than cast iron, annual energy consumption in large-flow scenarios (such as ≥300m³/h) is still 5%-8% higher than screw sewage pumps, with 10,000-15,000 kWh more annual power consumption. Casting carbon emissions are 38% higher than aluminum alloy, requiring energy consumption reduction through green casting processes (such as vacuum casting) to respond to the "dual-carbon" policy.

IV. Application Scenarios

Municipal Sewage Treatment: 316 stainless steel pumps are used in municipal sewage networks and lift stations of sewage treatment plants to handle domestic sewage and rainwater mixed water quality (pH6-9, with slight sediment).

Industrial Wastewater Treatment: Duplex stainless steel pumps are suitable for wastewater discharge in chemical, pharmaceutical, electroplating, and other industries, resisting corrosive sewage containing acids, alkalis, and heavy metal ions (such as wastewater with pH2-13).

Building Drainage Systems: 304 stainless steel pumps are used for sewage lifting in high-rise buildings and basement sewage discharge, handling domestic sewage containing feces, tissues, and other impurities, used in conjunction with sumps.

Special Working Condition Sewage Discharge: High-alloy stainless steel pumps are used in food processing (resisting oily sewage), mines (sediment-laden sewage), and other scenarios to meet the sewage discharge needs of different industries.

V. Precautions

Working Condition Adaptation: Avoid using 304 stainless steel pumps in sewage with chloride ions >500ppm or sulfide >100ppm; select 316 or duplex stainless steel. When water temperature exceeds 80℃, control pump operation time to prevent seal aging.

Maintenance Recommendations: Flush the pump cavity with high-pressure water quarterly to remove fibrous impurity deposits. Regularly inspect impeller wear (allowable blade thickness wear ≤1mm) to avoid efficiency decline caused by blockage.

Environmental Protection and Compliance: Products must comply with CJ/T 3038-1995 Submersible Sewage Pumps standards. When used for industrial wastewater, ensure corrosion resistance meets industry discharge requirements, and use anti-corrosion coatings for enhanced protection if necessary.