Stainless Steel Ejector Sewage Pump

I. Product Overview

Marine stainless steel ejector sewage pumps are high-efficiency environmental protection equipment designed for ship sewage discharge systems, 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 and treatment of ship sewage (containing oil, solid particles, 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 sewage, which is then pressurized by a diffuser and discharged, suitable for compliant discharge of domestic sewage, engine room sewage, and cargo hold sewage. After solution treatment and electropolishing reinforcement, the stainless steel has 80% better seawater corrosion resistance than cast steel, operating stably in seawater with Cl⁻≤30,000ppm and sewage with pH 5-10. It meets IMO MARPOL Annex IV anti-pollution conventions and international classification society certifications (LR, ABS, DNV, etc.), widely used in cargo ships, passenger ships, engineering vessels, and offshore platforms.

II. Core Technologies and Material Characteristics

1.Stainless Steel Material Selection and Performance

2.Key Technical Parameters

Flow range: 30-300m³/h, suitable for ships of 1,000-35,000 tons

Head: 18-50m, self-priming height ≥9m, start-up response time ≤15s

Impurity passing capacity: Passes ≤12mm solid particles and ≤25mm fibrous impurities, clogging risk reduced by 99%

Structural strength: Stainless steel components tested by ultrasonic testing (UT), bearing 5x rated pressure

Corrosion resistance design: Electropolished surface (Ra≤0.6μm), passing 6,000-hour salt spray test without rust, 85% improved sewage erosion resistance

III. Technical Advantages and Innovative Design

1. Efficient Sewage Disposal 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, sediment, and other impurities in sewage, especially suitable for harsh conditions with complex impurities.

Intelligent pulse backwash: The suction chamber is equipped with a differential pressure sensor that automatically activates the pulse backwash system when vacuum decreases due to impurity accumulation, extending the maintenance cycle to 36 months.

2. Complex Condition Adaptability

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

Anti-winding structure: The diffuser inner wall adopts spiral guide grooves to effectively intercept fibrous impurities, avoiding winding and clogging, and increasing system reliability by 90%.

3. Long Life and Low Maintenance

Wear-corrosion resistance treatment: Stainless steel impeller surface treated by supersonic flame spraying tungsten carbide (thickness 250μm), 6x improved wear resistance, service life exceeding 45,000 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. Ship Domestic Sewage Treatment

Passenger ship sewage discharge: 316L stainless steel pumps treat domestic sewage for cruise ships, flow 60-120m³/h, combined with domestic sewage treatment plants (STP) to meet IMO emission standards.

Crew toilet sewage discharge: Provides negative pressure pumping for multi-deck cabins, self-priming height 10m, avoiding odor accumulation and improving living comfort.

2. Engine Room and Cargo Hold Sewage

Engine room sewage pumping: Duplex stainless steel 2205 pumps extract oily sewage from engine rooms, flow 50-150m³/h, anti-oil film adhesion design to prevent clogging.

Cargo hold sewage emergency discharge: Rapid drainage in case of cargo hold flooding, combined with emergency drainage systems to meet SOLAS emergency requirements.

3. Special Ships and Offshore Platforms

Engineering ship sewage systems: Treat sediment-containing sewage for dredgers, passing ≤12mm sediment particles to ensure compliant sewage discharge during construction.

Offshore platform sewage: High-pressure ejector pumps (head ≥35m) treat platform domestic sewage and industrial wastewater, adapting to complex offshore conditions.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Sewage type: Choose 316L stainless steel for domestic sewage, duplex steel 2205 for oily/particulate sewage

Ship tonnage: Select 316L for <10,000 tons, duplex steel 2205 for ≥10,000 tons (better strength)

Flow matching: Configure at 2x maximum sewage generation, e.g., 8,000-ton cargo ships recommend flow 120-180m³/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 (accuracy ≤20mm) quarterly, remove pump cavity oil sludge 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 IV Regulations for the Prevention of Pollution by Sewage from Ships 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