Marine Ejector Bilge Pump

I. Product Overview

Marine ejector bilge pumps are "efficient dredging equipment" in ship bilge water removal systems, designed specifically to clear bilge water, oil stains, and sediment mixtures. Through the ejector principle, they form negative pressure to suck in bilge water containing impurities, which is then discharged overboard after mixing and pressurization. Without an impeller, they can handle complex media with a solid content of ≤5%. Constructed with cast iron (HT200), wear-resistant cast iron (KmTBCr20Mo), or stainless steel (316L) as the main material, they rely on high-speed jet from the nozzle to generate a vacuum in the mixing chamber, drawing bilge water from the suction port to mix with the working fluid, and finally discharging it through the diffuser. The pump body undergoes anti-corrosion and wear-resistant treatment, with a service life of ≥8 years in -10℃~60℃ environments. It meets IMO International Convention for the Control and Management of Ships' Ballast Water and Sediments (MEPC.200(62)) and bilge pump certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in bilge drainage systems of cargo ships, oil tankers, fishing boats, and other vessel types.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 10-150m³/h, suitable for ships of 500-30,000 gross tons (e.g., 10,000 gross ton ships require flow ≥30m³/h)

Head coverage: 5-30m, meeting pressure requirements for drainage from bilge to overboard (including pipeline elbows and filter resistance losses)

Medium compatibility: Capable of conveying mixtures containing sediment (particle size ≤10mm), oil stains (concentration ≤10%), and wood chips, with temperatures ranging from -10℃ to 60℃

Self-priming performance: Self-priming height ≥4m, priming time ≤45 seconds, capable of direct startup without priming devices, suitable for low-level bilge water scenarios

Anti-clogging capability: Suction port diameter ≥50mm, combined with impeller-free design, achieving 98% passage rate for fibers, plastic bags, and other impurities, with a clogging rate 80% lower than centrifugal pumps

3.Safety and Anti-Clogging Design

Overload protection: Equipped with pressure switches, automatically cutting off power when outlet pressure exceeds 1.5 times the rated value due to pipeline blockage, avoiding pump body damage

Reverse check: A check valve installed at the suction port prevents bilge water backflow after shutdown, ensuring no need for re-priming during restart

Tilt-resistant structure: Flow attenuation ≤8% under ship heel ±20° and trim ±10° conditions, ensuring drainage capability in severe sea conditions

III. Technical Advantages and Innovative Design

1. Complex Media Handling Capacity

Dual-nozzle ejector structure: Adopts main and auxiliary dual-nozzle design. The main nozzle generates high-pressure jet to form negative pressure, while the auxiliary nozzle helps break large impurities (e.g., gravel ≤10mm in diameter), increasing impurity passage rate by 40% compared to single-nozzle designs.

Wide-channel flow path: The flow path diameter gradually expands from 50mm to 80mm from suction port to discharge port, reducing turbulent resistance. Pressure loss for sediment-laden water ≤0.1MPa, 30% lower than centrifugal pumps of the same specification.

2. Wear Resistance and Corrosion Resistance Enhancement

Wear-resistant cast iron surface treatment: The inner wall of KmTBCr20Mo pump bodies is overlay-welded with wear-resistant alloy (3mm thick) to achieve HRC60 hardness, doubling service life against sediment erosion compared to ordinary cast iron pumps.

Stainless steel anti-adhesion treatment: 316L flow components undergo sandblasting + Teflon coating (0.1mm thick) to reduce oil adhesion, extending cleaning intervals to 300 hours and reducing maintenance frequency by 50% compared to ordinary stainless steel pumps.

3. Adaptability to Ship Operating Conditions

Lightweight and portable design: Single unit weight ≤200kg (30m³/h model) with lifting rings, allowing manual transportation for temporary drainage in different cabins, suitable for emergency scenarios.

No lubrication system required: No mechanical seals or bearings, relying on medium self-lubrication, reducing vulnerable parts and lowering maintenance costs by 60% compared to gear pumps.

IV. Typical Application Scenarios

1. Routine Bilge Drainage

Cargo ship hold drainage: 10,000 gross ton dry cargo ships use cast iron ejector bilge pumps (flow 50-80m³/h, pressure 1.0MPa) to remove accumulated water (with low wood chips and sediment) from hold bottoms caused by rainwater and cargo leakage, ensuring dry bilges.

Oil tanker slop tank drainage: Ocean-going oil tankers use stainless steel ejector bilge pumps (flow 30-50m³/h, pressure 1.6MPa) to extract bilge water containing 10% oil, which is discharged after treatment by oil-water separators, meeting MEPC.107(49) emission standards.

2. Special Media Removal

Fishing boat hold dredging: Trawler boats are equipped with wear-resistant cast iron ejector pumps (flow 20-30m³/h, pressure 1.2MPa) to clear mixtures of fish scales, bone fragments, and sediment from holds, preventing bottom and odor.

Engineering ship bilge cleaning: Dredgers use dual-nozzle ejector pumps (flow 80-100m³/h, pressure 1.5MPa) to remove bilge water containing large amounts of sediment (particle size ≤8mm). Cooperating with high-pressure water guns, they can empty 50m³ cabins within 30 minutes.

3. Emergency Drainage Scenarios

Stranded ship bilge rescue: When a ship runs aground and bilge water enters due to hull damage, portable stainless steel ejector pumps (flow 15-20m³/h) connect to bilges via hoses, continuously draining water to maintain buoyancy and buy time for repairs.

Post-fire cargo hold drainage: After cargo hold fires, cast iron ejector pumps extract mixtures of fire-fighting foam and water (foam concentration ≤5%) at 40-60m³/h, preventing residual liquid from corroding cabins.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Medium type: Cast iron pumps for freshwater + low sediment; wear-resistant cast iron pumps for high sediment content; stainless steel pumps for oil-contaminated or seawater environments

Flow calculation: Configure 1.5 times the maximum bilge water accumulation rate; e.g., a hold with 10m³/h accumulation requires flow ≥15m³/h

Installation method: Horizontal installation for fixed bilge drainage; portable vertical pumps (with wheels) for temporary emergency drainage

2. Maintenance Points

Daily inspection: Start once a week (run for 10 minutes), check outlet pressure (fluctuation ≤±0.1MPa) and leaks to ensure emergency availability

Regular maintenance: Clean suction filters every 1000 hours (to prevent hair and fiber entanglement), inspect nozzle wear (replace when diameter expands ≤1mm)

Medium switching maintenance: Rinse the pump body with clean water for 10 minutes before switching from sewage to oil drainage to avoid impurity mixing and pipeline blockage

3. Compliance Inspection

Annual classification society inspection, focusing on verifying impurity-containing media conveyance capacity (flow attenuation ≤10% with 5% sediment content) and anti-clogging performance

Meets MEPC.200(62) Convention requirements for bilge water discharge, ensuring pump compatibility with oil-water separators

VI. Compliance and Certification

International standards: Complies with ISO 8316 marine bilge pump performance standards and IMO MEPC.200(62) bilge water management regulations

Classification society certifications: Obtained type approval for ejector bilge pumps from RS, LR, ABS, and CCS (including 500-hour sediment-laden water operation tests)

Environmental requirements: When used with marine oil-water separators, drained water contains ≤15ppm oil, meeting international anti-pollution standards