Marine Stainless Steel Bilge Pump

I. Product Overview

Marine stainless steel bilge pumps are core equipment in ship bilge water drainage systems, designed specifically to collect and discharge accumulated water (including oily sewage, rainwater, and leaked water) from engine rooms, cargo holds, and double bottoms. Constructed with 316L ultra-low carbon stainless steel (022Cr17Ni12Mo2) or 304 stainless steel (06Cr19Ni10) as the main material, they achieve efficient transportation of oil-containing, impurity-laden sewage through self-priming centrifugal pump principles. Their working principle involves a power source (electric motor or diesel engine) driving an impeller to rotate, generating a vacuum to draw bilge water into the pump, pressurize it, and discharge it overboard (when meeting standards) or transfer it to sewage tanks after oil-water separation pretreatment. This prevents water accumulation from submerging equipment and endangering ship safety. The pump body undergoes electrolytic polishing and passivation treatment, with a corrosion-resistant service life of ≥15 years in oily sewage and high-salt spray environments. It meets IMO International Convention for the Prevention of Pollution from Ships (MARPOL) Annex I and bilge pump certification requirements of classification societies such as LR and ABS, and is mandatory for all ships over 500 gross tons.

II. Core Technologies and Material Characteristics

1.Stainless Steel Material Selection and Performance

2.Key Technical Parameters

Flow range: 5-200m³/h, suitable for ships of 500-50,000 gross tons (e.g., 10,000 gross ton ships recommend flow ≥50m³/h)

Head coverage: 10-40m, meeting height requirements from bilge (lowest liquid level) to overboard discharge

Medium compatibility: Capable of conveying bilge water, rainwater with oil content ≤15% and solid content ≤3% (particle diameter ≤5mm), and small amounts of chemical leakage (pH 5-9)

Self-priming performance: Self-priming height ≥5m, priming time ≤60 seconds (interval from start-up to drainage), no manual priming required

Temperature adaptability: Wide-temperature operation from -10℃ to 80℃, capable of handling high-temperature leaked water in engine rooms (≤60℃)

3.Safety and Anti-Pollution Design

Equipped with oil content concentration sensors, automatically switching to sewage tanks when oil content in discharged water ≥15ppm, meeting IMO anti-pollution requirements

Impellers adopt anti-winding design, capable of passing fibrous impurities (e.g., ropes, plastic fragments) with length ≤300mm, reducing clogging rate by 90%

III. Technical Advantages and Innovative Design

1. Complex Sewage Transportation Capacity

Cutting-type impeller: Integrates tungsten carbide alloy cutting blades, capable of shredding solid impurities (e.g., metal chips, plastic blocks) with diameter ≤10mm. Combined with fully open flow channels, passability is 60% higher than ordinary impellers.

Gas-liquid separation structure: Built-in gas-liquid separation chamber in the pump can automatically discharge air from the medium (normal operation when gas content ≤10%), avoiding flow attenuation caused by cavitation.

2. Corrosion Resistance and Wear Resistance Enhancement

All-stainless steel flow components: Pump body, impeller, and pump cover are all forged from homogeneous stainless steel, avoiding galvanic corrosion from contact between dissimilar metals, with no pitting after 3000-hour salt spray tests.

Wear-resistant coating technology: Impeller surfaces are sprayed with nickel-based alloy (0.5mm thickness) with hardness up to HRC55, 3 times more wear-resistant than 316L stainless steel, suitable for sandy sewage scenarios.

3. Efficiency and Emergency Support

Dual power source adaptation: Reserved interfaces for electric motors and diesel engines, enabling quick switching to diesel engine drive when main power fails (switching time ≤5 minutes) to ensure emergency drainage.

Intelligent start-stop control: Linked with bilge water level sensors, automatically starting when water level ≥500mm and stopping when ≤100mm, ensuring stable operation even in unattended conditions.

IV. Typical Application Scenarios

1. Engine Room Bilge Drainage

Diesel engine room water accumulation discharge: 15,000 gross ton cargo ship engine rooms are equipped with 316L stainless steel bilge pumps, with flow 80-120m³/h and head 30m, capable of continuously conveying engine room sewage with 10% oil content, with stable outlet pressure at 1.2±0.1MPa, cooperating with oil-water separators to achieve compliant discharge.

High-temperature leaked water treatment: Gas turbine engine rooms use temperature-resistant 316L pumps with flow 30-60m³/h to handle 60℃ lubricating oil leaked water, with impellers resisting oil immersion for 10,000 hours without aging.

2. Cargo Hold and Deck Drainage

Bulk carrier cargo hold water accumulation: 50,000 gross ton bulk carriers are equipped with 316L stainless steel self-priming pumps, with flow 100-200m³/h and self-priming height 5m, quickly discharging residual rainwater (containing small amounts of sediment) from cargo holds after unloading, with drainage time ≤1 hour.

Passenger ship deck drainage: 3,000-passenger ships use 304 stainless steel bilge pumps with flow 20-50m³/h, collecting rainwater through deck drains and discharging it after filter screening to avoid water accumulation affecting passenger safety.

3. Emergency and Special Scenarios

Damaged cabin emergency drainage: After ship collisions, 316L stainless steel emergency bilge pumps start within 10 minutes, with flow 150-200m³/h, cooperating with fire water pipelines to quickly pump out damaged cabin water and buy time for rescue efforts.

Polar ship low-temperature drainage: In -20℃ environments, pump bodies are insulated with electric tracing to ensure start-up within 30 seconds, with flow 50-80m³/h, discharging bilge water containing ice crystals (freezing point -5℃) to avoid pipeline freezing.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Medium type: 316L stainless steel for oily sewage and high-salt environments; 304 stainless steel for freshwater and low-oil sewage

Drainage scale: Configure flow at 1/3 of the maximum bilge water volume; e.g., 100m³ cabin capacity recommends flow ≥30m³/h (draining to safe water level within 1 hour)

Environmental conditions: -20℃ start-up type for cold zone ships; cutting-type impellers for large amounts of impurities; dual power source type for emergency scenarios

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.2MPa), bearing temperature (≤70℃), and impeller vibration (≤4.5mm/s) every 600 hours

Regular maintenance: Clean suction grilles (aperture ≤8mm) monthly; replace mechanical seals (oil-resistant fluoroelastomer material) every six months; inspect impeller wear annually (allowable deviation ≤0.5mm)

In-depth maintenance: Conduct water pressure tests (1.5 times rated pressure) every 5 years; re-passivate 316L components; calibrate oil content sensor accuracy

VI. Compliance and Certification

International standards: Complies with IMO MARPOL Annex I and MEPC.107(49) bilge water discharge specifications

Classification society certifications: Passed type approval for bilge pumps by LR, ABS, CCS (including 1000-hour oily sewage operation tests)

Environmental requirements: Compatible with marine oil-water separators (15ppm), with discharged water quality meeting IMO MEPC.227(64) standards