Marine Centrifugal Freshwater Pump

I. Product Overview

Marine centrifugal freshwater pumps are the "power hub" of ship freshwater supply systems, designed specifically to transport clean media such as drinking water, washing water, equipment cooling freshwater, and boiler feed water. They perform the dual core functions of supplying crew domestic water and cooling ship power systems. Constructed with cast iron (HT250), bronze alloy (ZCuSn10Pb1), or stainless steel (304) as the main material, they use centrifugal force generated by high-speed rotation of centrifugal impellers to draw freshwater from storage tanks, pressurize it, and deliver it to various water points or cooling equipment via pipelines. The pump body undergoes precision machining and anti-oxidation treatment, with a corrosion-resistant service life of ≥10 years in ambient temperature freshwater and short-term high-temperature (≤80℃) environments. It meets IMO Ship Freshwater System Safety Guidelines (MSC.1/Circ.1580) and freshwater pump certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in freshwater supply and cooling circulation systems of passenger ships, cargo ships, yachts, and other vessel types.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 2-200m³/h, suitable for 50-5000 ship occupants (e.g., 1000-passenger ships require domestic water flow ≥20m³/h)

Head coverage: 10-50m, meeting pressure requirements for transportation from storage tanks to water terminals (including pipeline elbows and valve resistance losses)

Medium compatibility: Capable of conveying drinking water (meeting WHO water quality standards), cooling freshwater (with corrosion inhibitors), softened water (hardness ≤50mg/L as CaCO₃), and clean liquids with temperature ≤80℃

Suction performance: Suction lift ≥6m, net positive suction head (NPSH) ≤3m, suitable for water absorption from low-level storage tanks without additional priming devices

Operation efficiency: Hydraulic efficiency ≥85% under design conditions, 10% more energy-efficient than ordinary centrifugal pumps of the same specification, saving up to 6000kWh/year per unit

3.Safety and Sanitary Design

Sanitary-grade flow channels: Surface roughness of bronze alloy and stainless steel flow components ≤Ra0.8μm, meeting FDA food contact standards to prevent bacterial growth (colony count ≤10CFU/mL)

ressure protection device: Safety valves automatically relieve pressure when outlet pressure exceeds 1.2 times the rated value, preventing burst of domestic water pipes (pressure resistance ≤1.0MPa)

Low-noise operation: Impellers adopt low-noise hydraulic design, with operating noise ≤65dB (measured at 1 meter), meeting passenger cabin noise requirements

III. Technical Advantages and Innovative Design

1. Efficient Water Conveyance Capacity

Low cavitation impeller: Uses double-suction impellers and streamlined blades to reduce cavitation margin from 5m to 3m, enabling cavitation-free operation in low-level storage tanks (liquid level difference 6m) and extending pump life by 30%.

Wide operating condition adaptability: Flow can stably operate in the 30%-110% rated range; during low water consumption periods at night on passenger ships (flow reduced to 50%), efficiency remains ≥80%, avoiding losses from frequent start-stop cycles.

2. Sanitary and Corrosion Resistance Guarantees

Fully enclosed flow channels: Pump body, impeller, and seals use homogeneous materials to avoid galvanic corrosion from contact between dissimilar metals, ensuring iron and copper ion content in drinking water ≤0.3mg/L.

Sterile cleaning design: Flow channels have no dead corners and smooth transitions, supporting CIP in-situ cleaning (80℃ hot water + citric acid) to completely remove biofilms, meeting ship drinking water hygiene requirements.

3. Adaptability to Ship Scenarios

Tilt-resistant structure: Pump unit bases adopt elastic damping design, with flow fluctuation ≤5% under ship heel ±20° and trim ±10°, ensuring stable water supply in severe sea conditions.

Modular assembly: Core components (impeller, bearings, mechanical seal) feature a modular design, reducing replacement time to ≤2 hours and minimizing ship docking maintenance duration.

IV. Typical Application Scenarios

1. Domestic Water Supply

Passenger ship centralized water supply: 3000-passenger ships are equipped with bronze alloy centrifugal freshwater pump sets (3 units in parallel, single unit flow 30m³/h) with pressure 1.0MPa, delivering drinking water to guest rooms and restaurants via pipelines, with constant pressure control ensuring stable shower water temperature (±2℃).

Yacht independent water supply: Luxury yachts use stainless steel centrifugal freshwater pumps (flow 5-10m³/h) to draw water from freshwater tanks to kitchens and bathrooms, with sanitary-grade flow channels ensuring water safety and low-noise operation meeting cabin comfort requirements.

2. Equipment Cooling Circulation

Main engine cooling system: 15,000kW main engines are equipped with stainless steel centrifugal freshwater pumps (flow 100-150m³/h, head 30m) to deliver cooling freshwater to cylinder liners and piston cooling chambers, controlling inlet water temperature at 30-40℃ and outlet temperature difference ≤10℃.

Generator cooling: 1000kW diesel generators use cast iron freshwater pumps (flow 10-15m³/h, head 20m) to provide circulating cooling water to generator cylinders, cooperating with thermostatic valves to stabilize outlet temperature at 65±3℃.

3. Special Freshwater Conveyance

Boiler feed water: Ship steam boilers use stainless steel centrifugal freshwater pumps (flow 5-20m³/h, pressure 2.5MPa) to deliver softened water to boiler drums, with water quality meeting standards (total dissolved solids ≤300mg/L) to avoid scaling and blockage.

Polar anti-freeze water supply: In -30℃ environments, bronze pumps with heating jackets convey antifreeze-containing freshwater (30% ethylene glycol concentration) at 15-30m³/h, preventing pipeline freezing and ensuring normal operation of research vessel freshwater systems.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Application scenarios: Bronze alloy pumps for drinking water and high hygiene requirements; stainless steel pumps for cooling systems and boiler feed water; cast iron pumps for inland short-haul use

Flow calculation: Configure 200L per person per day for domestic water (50L drinking water + 150L washing water); e.g., 500-person ships require flow ≥12.5m³/h

Pressure requirements: High-pressure models (1.6-2.5MPa) for cooling systems (main engines, generators); low-pressure models (0.6-1.0MPa) for domestic water

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.05MPa), bearing temperature (≤65℃), and seal leakage (≤1mL/h) every 800 hours

Regular maintenance: Replace mechanical seals (food-grade nitrile rubber) every 2000 hours; clean inlet filters (preventing algae blockage); inspect impeller wear (allowable radial clearance ≤0.2mm)

Sanitary maintenance: Circulate and disinfect domestic water pumps with 50ppm sodium hypochlorite solution for 30 minutes every 3 months to ensure water colony count ≤10CFU/mL

VI. Compliance and Certification

International standards: Complies with ISO 9001 quality management system and IMO MSC.1/Circ.1580 freshwater system guidelines

Classification society certifications: Passed type approval for freshwater pumps by RS, LR, ABS, and CCS (including 500-hour drinking water operation tests)

Sanitary certifications: Bronze alloy and stainless steel flow components meet FDA 21 CFR 175.300 and NSF/ANSI 61 drinking water system standards