Marine Ejector Freshwater Pump

I. Product Overview

Marine ejector freshwater pumps are the "efficient conveying core" of ship freshwater supply systems, designed specifically for freshwater needs such as crew domestic water, equipment cleaning, and boiler water replenishment. Through the ejector principle, they pressurize and convey clean water from ship freshwater tanks to various water points, achieving stable water supply from low pressure to high pressure. Constructed with cast iron (HT200), brass (H62), or stainless steel (304) as the main material, they rely on high-speed jet from the nozzle to generate negative pressure in the mixing chamber, sucking in freshwater, which is then pressurized and distributed to kitchens, bathrooms, engine rooms, and other areas via pipelines. They can complete self-priming and continuous conveyance without an impeller, making them particularly suitable for scenarios requiring high water quality cleanliness. The pump body undergoes rust-proof treatment and precision machining, with a service life of ≥8 years in 0℃~60℃ environments. It meets IMO International Maritime Organization Ship Accommodation Specifications (SOLAS Chapter II-1) and freshwater system certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in freshwater supply systems of passenger ships, cargo ships, fishing boats, and other vessel types.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 5-50m³/h, suitable for ships with 50-500 personnel (e.g., 200-person passenger ships require flow ≥15m³/h)

Head coverage: 10-30m, meeting water supply pressure requirements from freshwater tanks to high-rise cabins (including pipeline elbows and valve resistance losses)

Medium compatibility: Capable of conveying drinking freshwater (meeting GB 5749 standards), softened water, and boiler feed water, with temperatures ranging from 0℃ to 60℃ and turbidity ≤5NTU

Self-priming performance: Self-priming height ≥4m, priming time ≤30 seconds, capable of directly drawing water from low-level freshwater tanks without manual priming

Water supply stability: Outlet pressure fluctuation ≤±0.05MPa, with water pressure stability 20% higher than centrifugal pumps of the same specification, avoiding sudden temperature changes at water points

3.Safety and Sanitation Design

Water quality protection: Flow components use food-grade materials (brass/stainless steel) with smooth, free inner walls to prevent bacterial growth, meeting ship drinking water hygiene standards (colony count ≤100CFU/mL)

Dry-running protection: Equipped with liquid level sensors, automatically shutting down when freshwater tank levels are too low to prevent pump damage from dry friction

Silent operation: Adopting noise-reducing nozzles and rubber shock-absorbing bases, with operating noise ≤65dB (at 1 meter), meeting noise limit requirements for crew living areas

III. Technical Advantages and Innovative Design

1. Efficient Freshwater Conveying Capacity

Dual-chamber ejector structure: Adopts a "main ejector chamber + auxiliary pressure-stabilizing chamber" design, with water pressure 30% more stable than single-chamber ejector pumps. It can maintain a constant pressure output of 0.8MPa at a 30m head, ensuring sufficient water supply for high-rise cabins.

Intelligent flow regulation: Linked with water point sensors, automatically increasing ejector pressure (flow increases by 20%) when multiple faucets are opened simultaneously to avoid sudden pressure drops; automatically reducing frequency during low water usage periods, achieving 15% energy savings.

2. Sanitation and Corrosion Resistance Enhancement

Brass flow channel electrolytic polishing: H62 brass flow components undergo electrolytic polishing (Ra≤0.4μm) to reduce scale adhesion, requiring cleaning only once every six months to meet hygiene standards, extending maintenance intervals by 50% compared to ordinary brass pumps.

Stainless steel anti-scaling treatment: The inner wall of 304 stainless steel pump bodies is coated with a food-grade non-stick coating (0.05mm thick) to prevent calcium and magnesium ion deposition, suitable for conveying high-hardness freshwater (hardness ≤450mg/L as CaCO₃).

3. Adaptability to Ship Operating Conditions

Compact installation: Single unit volume ≤0.5m³ (15m³/h model), saving 40% installation space compared to centrifugal pumps of the same flow, suitable for installation in engine room corners or under living cabins.

Sway-resistant design: The pump body and base are connected with spring shock absorbers, with flow attenuation ≤5% under ship heel ±10° and trim ±5°, ensuring normal water supply in severe sea conditions.

IV. Typical Application Scenarios

1. Domestic Water Supply

Crew daily water use: 100-person cargo ships use cast iron ejector freshwater pumps (flow 10-15m³/h, pressure 0.6MPa) to draw clean water from freshwater tanks, which is filtered and delivered to crew dormitories and laundry rooms, with water pressure stable at 0.4-0.5MPa to meet washing and laundry needs.

Passenger ship centralized water supply: 300-person passenger ships use brass ejector pumps (flow 20-30m³/h, pressure 1.0MPa) to supply water to guest rooms and restaurants via zoned pipelines, cooperating with pressure tanks to achieve "instant water on demand" and avoid energy waste from pipeline idling.

2. Equipment and Cleaning Water

Boiler water replenishment: Auxiliary boilers on cargo ships use stainless steel ejector pumps (flow 5-8m³/h, pressure 1.2MPa) to deliver softened water to boilers, with water temperature ≤40℃ and water hardness ≤0.03mmol/L to prevent boiler scaling.

Deck cleaning: Fishing boat deck cleaning uses cast iron ejector pumps (flow 15-20m³/h, pressure 0.8MPa) to pressurize freshwater to 0.6MPa via high-pressure water guns, quickly removing residual fish stains.

3. Special Freshwater Conveyance

Desalinated water supply: Ocean-going cargo ships are equipped with 304 stainless steel ejector pumps (flow 20-25m³/h) to convey freshwater produced by seawater desalination equipment (salt content ≤500ppm), meeting crew drinking and kitchen cooking needs.

Emergency water supply: When the main freshwater system fails, portable brass ejector pumps (flow 5-10m³/h) connect to backup freshwater tanks via hoses to provide emergency water for key areas (e.g., medical rooms) with ≥8 hours.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Water usage scenarios: Cast iron/brass pumps for domestic water; stainless steel pumps for drinking water and boiler water replenishment

Flow calculation: Configure according to 200L daily water consumption per person (including losses); e.g., a 300-person ship requiring 60m³ water daily needs flow ≥10m³/h (based on 6 hours of operation)

Pressure requirements: 0.4-0.8MPa for low-rise cabins; 1.0-1.6MPa for high-rise cabins (≥5 floors)

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.05MPa) and water leakage every 300 hours to ensure stable water supply

Regular maintenance: Clean inlet filters every 1000 hours (to prevent algae and impurity blockage); inspect nozzle wear (replace when diameter expands ≤0.3mm)

Sanitation maintenance: Rinse the pump body with 5% citric acid solution for 1 hour every quarter to remove inner wall scale and ensure water quality safety

3. Compliance Inspection

Annual classification society inspection, focusing on verifying water quality cleanliness (heavy metal content ≤0.01mg/L) and water supply stability

Meets SOLAS Convention requirements for ship freshwater systems, ensuring emergency water supply in critical situations (e.g., fires)

VI. Compliance and Certification

International standards: Complies with ISO 10816 marine pump vibration standards and IMO ship freshwater system hygiene specifications

Classification society certifications: Obtained type approval for ejector freshwater pumps from RS, LR, ABS, and CCS (including 1000-hour clean water operation tests)

Hygiene certification: Flow components meet GB 4806.11 Food Contact Metal Materials and Products standards