Marine Cast Iron Bilge Pump

I. Product Overview

Marine cast iron bilge pumps are core equipment for ship bilge drainage systems, constructed with high-strength ductile iron (QT400-18) or gray cast iron (HT250), enabling efficient pumping of bilge wastewater through centrifugal or positive displacement pump principles. The working principle utilizes centrifugal force from impeller rotation or volume changes from pistons/gears to draw bilge water containing oil, sediment, and fibrous impurities through the suction pipe, pressurize it, and deliver it to wastewater treatment units or compliant discharge areas via the discharge pipe. The pump body undergoes integral casting and epoxy resin anti-corrosion coating, with a corrosion-resistant service life ≥8 years in seawater with Cl⁻≤20,000ppm, complying with IMO MARPOL Annex I anti-pollution conventions and classification society certifications (LR, ABS, etc.), widely used in bilge drainage for merchant ships, engineering vessels, and offshore platforms.

II. Core Technologies and Material Characteristics

1.Cast Iron Material Selection and Performance

2.Key Technical Parameters

Flow range: 20-200m³/h, suitable for 500-30,000-ton vessels

Head: 10-40m, meeting long-distance transportation and lifting requirements for bilge water

Impurity passing capacity: Centrifugal pumps pass ≤5mm solid particles; positive displacement pumps pass ≤8mm fibrous impurities

Corrosion resistance design: Epoxy resin coating thickness ≥200μm, 1,000-hour salt spray test passed without rust

Temperature adaptability: Stable operation at -20℃~60℃

III. Technical Advantages and Innovative Design

1. Efficient Wastewater Disposal and Anti-Clogging

Large-curvature flow channel design: Parabolic guide grooves at the impeller inlet, combined with a diffuser's gradually expanding structure, increase impurity passing capacity by 30% and reduce clogging risk by 85%.

Anti-winding impeller: Positive displacement pumps adopt open impellers or cycloidal gear structures, reducing fibrous impurity winding probability by 90%, suitable for bilge water containing rags and cable debris.

2. Complex Condition Adaptability

Anti-tilt operation: Axial force balancing device ensures stable drainage under ship heel 22° and trim 10°, meeting emergency bilge water discharge needs in critical conditions.

Low-temperature start-up resistance: With electric tracing systems at -20℃, start-up response time ≤15 seconds, preventing pump damage from wastewater freezing.

3. Long Life and Low Maintenance

Wear-resistant coating process: Impeller surface treated with supersonic sprayed ceramic layer (thickness 100μm), wear rate ≤0.02mm/1000h in wastewater with sediment content ≤300ppm.

Modular maintenance structure: Flange quick-release design for pump cover and body reduces single-component replacement time by 50%, lowering life-cycle maintenance costs by 35%.

IV. Typical Application Scenarios

1. Merchant Ship Bilge Drainage

Cargo ship engine room bilge discharge: Equips 50,000-ton cargo ships with ductile iron centrifugal pumps, flow 80-120m³/h, pumping oily engine room wastewater and achieving compliant discharge with oil-water separators.

Passenger ship sanitary bilge drainage: Inland cruise ships use gray cast iron positive displacement pumps, flow 30-50m³/h, negative pressure pumping of toilet wastewater to prevent odor diffusion.

2. Engineering Vessels and Special Ships

Dredger bilge sediment discharge: Engineering vessels equipped with wear-resistant ductile iron pumps pass ≤8mm sediment particles, flow 150-200m³/h, adapting to high-sediment wastewater discharge in dredging operations.

LNG ship bilge emergency drainage: Polar LNG ships equipped with low-temperature resistant cast iron pumps operate stably at -15℃, rapidly pumping bilge condensate.

3. Offshore Platforms and Ports

Drilling platform bilge drainage: Offshore platform bilge pumps, flow 100m³/h, head 30m, addressing emergency drainage needs from platform equipment leaks.

Port tugboat bilge cleaning: Tugboats use self-priming cast iron pumps, self-priming height ≥7m, quickly cleaning residual ballast water and oil from bilges.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Wastewater type: Centrifugal pumps for oily wastewater; positive displacement pumps for fibrous impurities; wear-resistant ductile iron pumps for high-sediment wastewater

Ship conditions: Ductile iron for ocean-going vessels; gray cast iron for inland vessels; insulated pump bodies for cold seas

Flow matching: Configure at 1.5x maximum bilge water generation, e.g., 10,000-ton cargo ships recommend flow 100-150m³/h

2. Maintenance Key Points

Daily monitoring: Inspect bearing temperature (≤70℃) and vibration value (≤4.5mm/s) every 400 hours

Regular maintenance: Clean suction filters (accuracy ≤10mm) monthly; inspect coating integrity quarterly; replace mechanical seals annually

In-depth maintenance: Hydraulic pressure test (1.2x rated pressure) every 3 years; replace impellers with wear exceeding 20%

VI. Compliance and Certification

International standards: Complies with IMO MARPOL Annex I anti-pollution convention and ISO 15085 ship drainage system specifications

Classification society certifications: Passed class certifications by LR, ABS, DNV GL, etc.

Environmental requirements: Wastewater discharge complies with MEPC.279(70) standards; 100% recyclable material