Stainless Steel Ejector Bilge Pumps for Marine Applications

I. Product Overview

Marine stainless steel ejector bilge pumps are high-efficiency environmental protection equipment designed for ship bilge water discharge, using 316L austenitic stainless steel or duplex stainless steel 2205 as the main material. Based on the ejector pump principle (Venturi effect), they enable rapid pumping of bilge water (containing oil, sediment, fibrous impurities, etc.). The working principle is that high-pressure water forms a high-speed jet through a stainless steel nozzle, creating vacuum negative pressure in the suction chamber to draw in bilge water, which is then pressurized by a diffuser and discharged, suitable for bilge drainage in cargo ships, passenger ships, and special vessels. After solution treatment and passivation coating reinforcement, the stainless steel has 50% better seawater corrosion resistance than cast steel, operating stably in seawater with Cl⁻≤30,000ppm, meeting IMO MARPOL Annex I anti-pollution conventions and international classification society certifications (LR, ABS, DNV, etc.).

II. Core Technologies and Material Characteristics

1.Stainless Steel Material Selection and Performance

2.Key Technical Parameters

Flow range: 40-350m³/h, suitable for ships of 1,000-30,000 tons

Head: 18-45m, self-priming height ≥9m, start-up response time ≤15

Impurity passing capacity: Passes ≤10mm solid particles and ≤20mm fibrous impurities, clogging risk reduced by 99%

Structural strength: Stainless steel components tested by ultrasonic testing (UT), bearing 4x rated pressure

Corrosion resistance design: Electropolished surface (Ra≤0.6μm), passing 6,000-hour salt spray test without rust, achieving the highest IMO anti-biofouling rating

III. Technical Advantages and Innovative Design

1. Efficient Drainage and Anti-Clogging Capability

Non-rotating component design: Ejector pumps have no vulnerable parts such as impellers or shafts. Large-diameter flow channel design ensures smooth transport of rags, rust, and other impurities in bilge water, especially suitable for harsh conditions with complex impurities.

Intelligent pulse backwash: The suction chamber is equipped with a pressure sensor that automatically activates the pulse backwash system when vacuum decreases due to impurity accumulation, extending the maintenance cycle to 24 months.

2. Extreme Condition Adaptability

All-attitude operation technology: Stable drainage under ship trim 28° and list 15°, combined with anti-tilt sensors, ensuring timely bilge water discharge in emergencies.

Explosion-proof safety design: Stainless steel generates no sparks during friction. Combined with explosion-proof motors (Ex d IIB T6), it is suitable for hazardous bilges with combustible gases (e.g., oil tanker cargo bilges).

3. Long Life and Low Maintenance

Wear-corrosion resistance treatment: Stainless steel impeller surface treated by supersonic flame spraying tungsten carbide (thickness 200μm), 6x improved wear resistance, service life exceeding 40,000 hours.

Modular quick-release structure: Pump body and pipelines use clamp-type quick-connect design, reducing single-component replacement time by 85% and life-cycle maintenance costs by 50%.

IV. Typical Application Scenarios

1. Merchant Ship Bilge Drainage

Cargo ship engine room bilge: 316L stainless steel ejector pumps drain engine room water with lubricating oil, flow 100-200m³/h, combined with oil-water separators for compliant discharge (oil content ≤15ppm).

Passenger ship sanitary bilge: Provides negative pressure drainage for multi-deck cabins, self-priming height 10m, ensuring rapid discharge of domestic sewage and avoiding odor accumulation.

2. Special Vessel Emergency Drainage

Offshore engineering vessels: Duplex stainless steel 2205 ejector pumps drain at ≥250m³/h under drilling platform tilt conditions, meeting SOLAS emergency requirements.

LNG ship bilge: Low-temperature resistance design (-40℃) can drain low-temperature bilge water after LNG leakage, combined with insulated pipelines to ensure system safety.

3. Oil Tankers and Hazardous Cargo Vessels

Oil tanker cargo bilge: Anti-static stainless steel ejector pumps (grounding resistance ≤2Ω) drain bilge water with crude oil residues, avoiding explosion risks from sparks.

Chemical tanker bilge: Duplex steel 2205 effectively resists corrosion from chemicals like methanol and hydrochloric acid, ensuring safe drainage system operation.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Water quality conditions: Choose 316L stainless steel for conventional bilge water, duplex steel 2205 for high-salinity/particulate/corrosive media

Ship conditions: Ocean-going vessels and special operation ships require duplex steel 2205 (superior anti-tilt performance)

Flow matching: Configure at 2x maximum bilge water generation, e.g., 10,000-ton cargo ships recommend flow 180-250m³/h

2. Maintenance Key Points

Daily monitoring: Real-time monitoring of inlet/outlet pressure and vacuum, ensuring pressure fluctuation ≤±8%

Regular maintenance: Clean suction grilles (filtration accuracy ≤15mm) quarterly, remove pump cavity dirt with special cleaners annually

In-depth maintenance: Nondestructive testing every 3 years, reapply passivation coating, and inspect seal status

VI. Compliance and Certification

International standards: Complies with IMO MARPOL Annex I Regulation 15 for bilge water discharge and ISO 15085 ship drainage system specifications

Classification society certifications: Passed LR Rules for the Classification of Ships and ABS Rules for Building and Classing Ships

Environmental requirements: Components in contact with sewage comply with FDA food-grade standards, and stainless steel is 100% recyclable