Marine Ejector Cooling Water Pump

I. Product Overview

Marine ejector cooling water pumps are "efficient heat dissipation tools" in ship power equipment cooling systems, designed specifically for cooling cycles of diesel engines, generators, and other equipment. They pressurize seawater or freshwater into high-speed cooling water flows through the ejector principle, quickly dissipating heat generated by equipment operation and maintaining operating temperatures within a safe range (≤95℃). Constructed with cast iron (HT250), bronze alloy (ZCuSn10Pb2), or stainless steel (316L) as the main material, they rely on high-speed jet from the nozzle to generate negative pressure in the mixing chamber, sucking in cooling media, which is then pressurized and delivered to the equipment cooling chamber. Achieving self-priming and continuous conveyance without an impeller, they are particularly suitable for cooling scenarios with small amounts of impurities. The pump body undergoes anti-corrosion treatment and pressure-resistant processing, with a corrosion-resistant service life of ≥8 years in -10℃~80℃ environments. It meets IMO Ship Machinery Cooling System Specifications (MSC.389(94)) and cooling equipment certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in cooling systems of power equipment for small and medium-sized ships such as fishing boats, cargo ships, and engineering vessels.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 15-150m³/h, suitable for equipment power 500-10,000kW (e.g., 3000kW main engines require flow ≥30m³/h)

Head coverage: 10-40m, meeting pressure requirements for transportation from overboard/water tanks to equipment cooling chambers (including pipeline elbows and filter resistance losses)

Medium compatibility: Capable of conveying seawater (sediment content ≤1%), freshwater, ethylene glycol antifreeze (concentration ≤30%), with temperatures ranging from -10℃ to 80℃

Self-priming performance: Self-priming height ≥5m, priming time ≤30 seconds, capable of directly drawing water from overboard or low-level tanks without manual priming

Heat dissipation efficiency: Cooling medium temperature rise ≤15℃ (inlet-outlet temperature difference of equipment), with heat dissipation speed 10% higher than centrifugal pumps of the same flow

3.Safety and Stability Design

Temperature interlock protection: Equipped with temperature sensors, automatically increasing ejector pressure (flow increases by 15%) when equipment outlet water temperature ≥95℃; triggering alarms when exceeding 100℃

Debris-proof structure: A 3mm aperture filter installed at the suction port, combined with impeller-free design, allowing passage of sediment particles ≤5mm in diameter, with a clogging rate 70% lower than centrifugal pumps

Impact-resistant performance: The pump body and base are connected with rubber shock pads, capable of withstanding ship heel ±15° and trim ±10°, ensuring uninterrupted cooling

III. Technical Advantages and Innovative Design

1. Efficient Cooling and Conveying Capacity

Multi-stage ejector structure: Adopts a "nozzle + mixing chamber + diffuser" three-stage design, increasing water flow speed by 25% compared to single-stage ejector pumps. It can still maintain a jet speed of 20m/s at a 40m head, enhancing heat exchange efficiency on equipment surfaces.

Wide flow regulation: Flow can be steplessly adjusted within the 40%-110% rated range through frequency conversion control or bypass valves, adapting to heat dissipation needs during equipment idle (small flow) and full load (large flow).

2. Corrosion Resistance and Wear Resistance Enhancement

Bronze flow channel polishing: ZCuSn10Pb2 flow components undergo mirror polishing (Ra≤0.8μm) to reduce marine organism adhesion, showing no rust after 3000 hours of immersion in 3% salt spray environment, suitable for long-term coastal use.

Cast iron pump anti-corrosion treatment: The inner wall of HT250 pump bodies is sprayed with an epoxy resin coating (0.3mm thick), improving freshwater erosion resistance by 50% compared to ordinary cast iron, extending maintenance intervals to 2000 hours.

3. Adaptability to Ship Operating Conditions

Lightweight design: Single unit weight ≤200kg (50m³/h model), 30% lighter than centrifugal pumps of the same flow, suitable for installation in narrow spaces such as engine room tops or decks.

Anti-clogging advantage: No vulnerable parts such as impellers or bearings, achieving 95% passage rate for aquatic plants, small shells, and other impurities in cooling water, reducing shutdown risks due to clogging.

IV. Typical Application Scenarios

1. Power Equipment Cooling

Diesel engine cooling: 5000kW fishing boat main engines use bronze alloy ejector cooling water pumps (flow 40-60m³/h, pressure 1.2MPa) to draw seawater (sediment content ≤1%) into cylinder liner cooling chambers, controlling inlet water temperature ≤35℃ and outlet temperature at 85±2℃, ensuring main engine thermal efficiency ≥40%.

Generator cooling: Cargo ship diesel generators are equipped with cast iron ejector cooling water pumps (flow 15-25m³/h, pressure 1.0MPa) to cool stators through freshwater closed-loop circulation. Flow automatically adjusts with generator load (reducing to 50% at idle), stabilizing water temperature at 65-75℃.

2. Special Equipment Heat Dissipation

Fish hold refrigeration unit cooling: Refrigeration compressors in refrigerated fish holds use stainless steel ejector pumps (flow 20-30m³/h, pressure 1.6MPa) to convey low-temperature seawater (5-10℃) for condenser cooling, controlling condensation temperature at 35±3℃ and improving refrigeration efficiency by 8%.

Hydraulic system cooling: Engineering ship hydraulic stations use dual-nozzle ejector pumps (flow 30-40m³/h, pressure 1.5MPa) to cool hydraulic oil (viscosity ≤200cSt), reducing oil temperature from 60℃ to 40℃ and preventing high-temperature aging of hydraulic components.

3. Extreme Environment Adaptation

Low-temperature startup cooling: In -10℃ environments, ejector pumps with heating jackets (1.5kW power) heat antifreeze (30% concentration) to 10℃, maintaining flow at 10-15m³/h and ensuring unobstructed cooling systems during research vessel generator startup.

High-temperature sea area heat dissipation: In 35℃ tropical sea areas, stainless steel ejector pumps convey seawater to diesel main engines at 50-70m³/h. By enlarging nozzle diameter, cooling water temperature rise is controlled within 10℃, avoiding main engine overheating shutdown.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Cooling medium: Cast iron/bronze pumps for freshwater and low-salinity seawater; stainless steel pumps for high-salinity seawater and chemicals

Flow calculation: Configure 1.2 times the equipment heat dissipation; e.g., equipment with 1000kW heat dissipation per hour (requiring 0.1L/s cooling water per kW) requires flow ≥43.2m³/h

Pressure requirements: Low-pressure cooling systems (generators, hydraulic stations) select 0.8-1.2MPa; high-pressure systems (main engine cylinder liners) select 1.2-2.0MPa

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.1MPa), filter clogging, and pump body leakage every 600 hours

Regular maintenance: Clean inlet filters every 2000 hours; inspect nozzle wear every 3000 hours (replace when diameter expands ≤0.5mm)

Seasonal maintenance: Inject antifreeze (concentration ≥20%) into cast iron pumps of freshwater cooling systems before winter to prevent pump body freezing

3. Compliance Inspection

Annual classification society inspection, focusing on verifying flow stability, heat dissipation efficiency, and compatibility with cooling systems

Meets IMO requirements for ship machinery cooling systems, ensuring equipment operating temperatures do not exceed design limits (e.g., diesel engine cylinder head temperature ≤150℃)

VI. Compliance and Certification

International standards: Complies with ISO 8861 marine diesel engine cooling system standards and IMO MSC.389(94) cooling equipment guidelines

Classification society certifications: Obtained type approval for ejector cooling water pumps from RS, LR, ABS, and CCS (including 2000-hour seawater circulation tests)

Material compliance: Flow-through components meet ASTM B584 (bronze), ASTM A48 (cast iron), and ASTM A240 (316L stainless steel) standards