Copper Centrifugal Fire Pump

I. Product Overview

Copper centrifugal fire pumps are designed based on the centrifugal force transportation principle, using copper and copper alloys (brass, bronze, etc.) as the core material, providing efficient and reliable liquid pressurization solutions for fire water supply systems. The copper impeller and pump body, combined with fire condition optimization design, integrate excellent water corrosion resistance, vibration resistance, and emergency condition adaptability, enabling stable operation in fresh water, seawater, and fire extinguishing media with minor impurities. They meet the requirements of GB 6245 Fire Pumps, GB 50974 Technical Code for Fire Water Supply and Hydrant Systems, and international fire certifications (such as UL, FM).

II. Core Materials and Performance Adaptation

1.Brass (Cu-Zn Alloy)

Characteristics

Zinc content 6-40%, commonly used H62/H68 brass, tensile strength ≥300MPa, excellent fresh water corrosion resistance (pH6-8), corrosion rate <0.05mm/year in seawater (Cl⁻ concentration 20000ppm), thermal conductivity reaches 109W/(m・K), 3 times that of cast iron, effectively reducing pump body temperature rise.

Moderate cost, easy to process and form, suitable for manufacturing non-load-bearing components such as pump bodies and pump covers.

Application Scenarios

Ordinary industrial and civil fire protection systems (such as fire hydrant systems in office buildings and shopping malls), transporting municipal tap water or softened water (hardness ≤450mg/L).

2.Tin Bronze (Cu-Sn Alloy, such as ZCuSn10Pb1)

Characteristics

Contains 10% tin and 1% lead, tensile strength ≥350MPa, hardness HB≥80, wear resistance 40% higher than brass, outstanding cavitation resistance (bubble collapse impact strength ≤200MPa), suitable for high-head conditions (>100m).

Excellent seawater corrosion resistance (with nickel, Cl⁻ concentration resistance up to 30000ppm), self-healing surface oxide film reduces electrochemical corrosion.

Application Scenarios

Marine seawater fire protection systems, coastal storage tank fire pumps, transporting sediment-laden seawater (sand content ≤1%); high-speed centrifugal pump impellers (speed ≥2900r/min), resisting high-speed liquid scouring wear.

3.Aluminum Bronze (Cu-Al Alloy, such as ZCuAl10Fe3)

Characteristics

Contains 10% aluminum and 3% iron, tensile strength ≥600MPa, hardness HB≥150, excellent impact resistance (impact toughness ≥35J/cm²), can withstand water hammer pressure during fire system startup (≤1.5 times working pressure).

In fire extinguishing media with trace corrosive ions (such as SO₄²⁻, HCO₃⁻), corrosion resistance is 2 times higher than brass, suitable for chemical park fire protection scenarios.

Application Scenarios

High-pressure water mist fire extinguishing systems (working pressure ≥10MPa), fire pumps in explosion-proof areas (such as oil depots and natural gas stations). The non-sparking property of copper alloys (friction spark ignition energy ≥50mJ) meets explosion-proof requirements (Ex nA IIC T4).

III. Technical Advantages and Application Limitations

Core Technical Advantages

1. Corrosion Resistance and Fire Condition Adaptation

Tin bronze impellers have a service life of over 15 years in seawater fire protection systems, 3 times that of cast iron impellers. The pump body uses integral copper casting technology (sand casting or centrifugal casting), surface roughness Ra≤12.5μm, reducing scale deposition (scaling rate 60% lower than cast iron).

2. High-Efficiency Pressurization and Reliability

Closed impeller design achieves hydraulic efficiency of 75%-85%, 10% higher than open impellers, with flow stability error ≤±3% under 0.6MPa pressure. Equipped with a self-priming device (such as a vacuum priming pump), the first water absorption time ≤60 seconds to meet emergency fire startup needs.

3. Explosion-Proof Safety and Low Maintenance

Aluminum bronze components do not generate sparks during friction, suitable for inflammable and explosive places (such as environments with dust concentration >65g/m³). The copper surface requires no additional anti-corrosion coating, with maintenance costs 40% lower than cast iron pumps (cast iron needs annual rust removal and painting).

Application Limitations

1. Strong Corrosive Medium Restrictions

Brass pumps are prohibited for fire extinguishing media containing ammonia (NH₃) or concentrated nitric acid (HNO₃) (prone to stress corrosion cracking). In acidic water with pH<5 or alkaline water with pH>9, aluminum bronze must be selected with cathodic protection (such as zinc sacrificial anodes).

2. Cost and Weight Challenges

Copper materials cost 3-5 times more than cast iron (e.g., tin bronze pump body costs about 4 times that of cast iron), density 8.9g/cm³ is 15% higher than cast iron, increasing pump weight by 10-15kg for the same diameter, requiring reinforced foundations during installation.

3. Impurity Sensitivity

Impeller clearance 0.5-1.0mm, sensitive to solid particles >2mm (such as pipeline rust and sediment), requiring Y-type filters (filtration accuracy ≤5mm), otherwise wear rate increases to 0.05mm per thousand hours.

IV. Typical Application Scenarios

1. Industrial Fire Protection Systems

Chemical Enterprise Fire Protection: Aluminum bronze pumps transport sodium bicarbonate-containing (pH8-9) foam extinguishing agents, resisting alkaline medium corrosion, and cooperate with pressure sensors for constant pressure water supply (pressure fluctuation ≤±0.05MPa), meeting GB 50160 Code for Fire Protection Design of Petrochemical Enterprises.

Oil Depots and Storage Tank Areas: Tin bronze pumps serve as fixed fire cannon water supply pumps, transporting seawater or fresh water, with a head of 150-200m and flow rate of 200-500m³/h, ensuring rapid foam mixture  (rate ≥50L/s).

2. Marine and Offshore Engineering

Marine Seawater Fire Protection: Brass/tin bronze pumps are connected to marine seawater main pipes, supplying water to deck fire hydrants and water mist systems. Seawater corrosion-resistant design meets IMO SOLAS convention requirements for fire pumps (e.g., fire pump flow ≥25m³/h for ships over 3000 GT).

Offshore Platform Fire Protection: Aluminum bronze pumps operate stably in high-temperature (≤60℃) and high-salt fog environments, equipped with diesel engine drive units (backup power), ensuring continuous water supply ≥3 hours when the main power fails.

3. Special Building Fire Protection

High-Rise Building Fire Hydrants: Tin bronze pumps provide high-head water supply (head ≥150m), impellers use backward-leaning blades (β2=30°-45°) to reduce axial force, and cooperate with variable frequency control cabinets for variable flow pressure stabilization (pressure deviation ≤±2%).

Data Centers and Laboratories: Brass pumps transport deionized water (conductivity ≤10μS/cm) to precision gas fire extinguishing systems. The low electrical conductivity of copper materials (resistivity ≤0.02Ω・mm²/m) avoids static electricity accumulation risks.

V. Usage and Maintenance Specifications

1. Selection Notes

Medium Compatibility:

Fresh water/municipal water: Prioritize brass pumps (cost-effective);

Seawater/alkaline foam liquid: Select tin bronze or aluminum bronze pumps;

Strongly corrosive media (such as ammonium phosphate): Require stainless steel linings or all-fluoroplastic pumps.

Installation Environment:

When installed outdoors, the pump body must be sprayed with acrylic anti-corrosion paint (thickness ≥100μm) to prevent copper green (basic copper carbonate) deposition caused by sulfides (such as SO₂);

Explosion-proof areas require aluminum bronze impellers + explosion-proof motors (Ex d IIB T4), grounding resistance ≤4Ω.

2. Maintenance Key Points

Daily Monitoring:

Record inlet and outlet pressure daily (deviation ≤±5% of rated value), bearing temperature (temperature rise ≤40℃), equipped with vibration sensors (threshold ≤2.5mm/s), automatic alarm for abnormalities.

Regular Maintenance:

Clean the filter quarterly (replace the element when pressure difference >0.1MPa);

Disassemble and inspect impeller wear annually (blade thickness wear ≤1mm), use dilute hydrochloric acid (concentration 5-10%) to remove pump cavity scale (soaking time ≤30 minutes to avoid over-corrosion);

Replace mechanical seals when leakage >10 drops/minute, seal materials prefer silicon carbide/fluororubber (temperature resistance -20℃~120℃).

3. Compliance Requirements

Domestic products must pass CCCF fire product certification, providing corrosion resistance test reports for copper alloys (such as GB/T 10119-2021 Test Method for Ammonia Stress Corrosion of Copper and Copper Alloys);

Exports must comply with UL 448 standards (fire pump efficiency ≥70%) and FM 2000 certification (seismic performance meets 4.5g acceleration impact).

VI. Conclusion

Copper centrifugal fire pumps, with the corrosion resistance, wear resistance, and explosion-proof characteristics of copper alloys, become the preferred equipment for industrial, marine, and special building fire protection, particularly demonstrating significant advantages in seawater, alkaline media, and explosion-proof scenarios. During selection, precise matching of medium characteristics and working condition parameters is required. Regular maintenance ensures reliable operation in emergency situations while meeting the dual requirements of domestic and international fire protection standards for safety and efficiency.