Stainless Steel Centrifugal General Pump

I. Product Overview

Stainless steel centrifugal General pumps are designed based on the centrifugal force transportation principle, using austenitic stainless steel (such as 304, 316, 316L, etc.) as the core material. They are suitable for liquid transportation needs in industrial, civil, and environmental protection fields. The material system, combined with precision manufacturing processes, integrates excellent corrosion resistance, hygienic properties, and adaptability to complex working conditions, enabling stable operation in acid-base solutions, high-temperature media, and liquids with minor impurities. It meets the strict requirements of industries such as chemical, food, and pharmaceutical.

II. Core Materials and Characteristics

1.304 Stainless Steel

Characteristics: Contains 18% chromium (Cr) and 8% nickel (Ni), tensile strength ≥515MPa, resistant to general corrosion (such as weak acid-base, water), surface finish Ra≤0.8μm, complying with food hygiene standards.

Applications: Widely used in drinking water transportation, air-conditioning circulating water systems, and mildly corrosive media (such as aqueous solutions with pH 6-8).

2.316 Stainless Steel

Characteristics: Added with 2-3% molybdenum (Mo), significantly improved chloride ion corrosion resistance (can withstand Cl⁻ concentration ≤20000ppm), enhanced high-temperature stability (operating temperature ≤120℃), and pitting corrosion resistance 3 times higher than 304.

Applications: Suitable for seawater desalination pretreatment, acid-base liquid transportation in chemical processes (such as sulfuric acid concentration ≤15%), and marine ballast water systems.

3.316L Stainless Steel

Characteristics: Carbon content ≤0.03%, excellent intergranular corrosion resistance after welding, outstanding stress corrosion cracking resistance, and stable operation in the range of -20℃~150℃.

Applications: Sterile liquid transportation in the pharmaceutical industry, CIP/SIP cleaning systems in food and beverage processing, and high-temperature and high-pressure chemical reactor circulation.

III. Technical Advantages and Limitations

Core Advantages

1. Corrosion Resistance and Hygienic Performance

The annual corrosion rate of 316L stainless steel impellers in media with Cl⁻ concentration 10000ppm is <0.1mm, extending the service life by 5 times compared to cast iron pumps. The surface roughness Ra≤0.4μm complies with FDA and GMP standards, suitable for food-grade liquid transportation.

2. High Efficiency, Energy Saving, and Stability

Closed impeller design achieves hydraulic efficiency of 75%~85%, 15% more energy-efficient than open impellers. Precision dynamic balance treatment (residual unbalance ≤2.5g・mm) ensures operation vibration ≤1.5mm/s and noise ≤70dB.

3. Convenient Maintenance and Cost Optimization

Modular structure design allows mechanical seal replacement in only 30 minutes, with maintenance costs 40% lower than multistage pumps. Stainless steel materials have a service life of over 10 years, with full life cycle costs 20% lower than engineering plastic pumps.

Main Limitations

1. High-Temperature and High-Viscosity Restrictions

304 stainless steel is prone to stress corrosion in strongly alkaline media (pH>12) at >80℃; 316L with a cooling jacket is required. When transporting liquids with viscosity >100cP, efficiency decreases by 10%~15%.

2. Cost and Weight Challenges

316L stainless steel is 3~5 times more expensive than cast iron, with a density of 7.9g/cm³ (2.5 times higher than aluminum alloy), requiring special supports for installation. Large-flow models (>500m³/h) have higher motor power, increasing energy consumption costs.

3. Impurity Adaptability Limitations

Closed impellers are sensitive to solid particles (>2mm) and require pre-filters. Fiber-containing media easily entangle the shaft seal; open impellers should be selected with regular cleaning.

IV. Application Scenarios

1. Chemical and Petrochemical Industries

316L stainless steel pumps transport concentrated sulfuric acid (concentration ≤98%) and caustic soda solution (concentration ≤30%), resisting medium corrosion and high temperature (≤120℃).

2. Food, Beverage, and Pharmaceutical

304 stainless steel pumps are used in milk pasteurization systems and liquid medicine filling lines, with electrolytic polishing treatment (Ra≤0.2μm) to prevent microbial growth.

3. Water Treatment and Environmental Protection

316 stainless steel pumps handle electroplating wastewater containing heavy metal ions (such as Cr⁶⁺, Ni²⁺), resistant to wide-range corrosion of pH 2~12. Self-priming design quickly drains sewage pool water.

4. Construction and HVAC

304 stainless steel pipeline pumps are used for constant pressure water supply in high-rise buildings, with a flow range of 5~500m³/h and a maximum head of 150m, transporting chilled water (-10℃~70℃) in closed-loop systems.

V. Precautions

1. Media Adaptability

High-silicon stainless steel (such as 316Ti) should be selected for transporting strongly oxidizing acids (such as concentrated nitric acid). For media containing solid particles (such as mineral slurry), downgrade to 316L and reduce the rotation speed to 1450r/min.

Configure cooling pipelines for high-temperature conditions (>100℃) to prevent mechanical seal overheating failure. Use 316L and add antifreeze in low-temperature environments (<-10℃).

2. Installation and Maintenance

The foundation flatness error should be ≤0.1mm/m, and the coaxiality error between the pump shaft and motor shaft should be ≤0.05mm. Soft connections should be set in inlet and outlet pipelines to avoid stress transfer.

Check bearing temperature rise (≤35℃) weekly and replace lubricating oil (ISO VG 46) quarterly. Replace mechanical seals promptly when leakage exceeds 5 drops/minute.

3. Compliance Requirements

Food industry applications require FDA certification (such as 316L material), and pharmaceutical industry applications must comply with GMP standards (such as surface roughness Ra≤0.4μm).

In explosive areas (such as petrochemical workshops), use explosion-proof motors (Ex d IIB T4) and configure leakage detection sensors.