Marine Cast Steel Bilge Pump

I. Product Overview

Marine cast steel bilge pumps are key equipment for removing bilge water from ships, designed specifically to clear accumulated water, oil contaminants, and impurity-laden sewage from bilges. Constructed with high-strength alloy cast steel (WC6) or carbon cast steel (WCB), they achieve efficient transportation of high-viscosity, impurity-containing media through centrifugal or reciprocating pump principles. Their working principle involves a power source (electric motor or diesel engine) driving an impeller or piston to generate negative pressure, drawing bilge water into the pump body, pressurizing it, and discharging it overboard or to sewage treatment devices via pipelines. This prevents accumulated water from affecting ship stability or corroding hulls. The pump body undergoes integral forging and anti-corrosion treatment, with a corrosion-resistant service life of ≥10 years in oily sewage and seawater environments. It meets IMO International Convention for the Prevention of Pollution from Ships (MARPOL) and certification requirements of classification societies such as LR and ABS, widely used in bilge drainage systems of cargo ships, oil tankers, passenger ships, and engineering vessels.

II. Core Technologies and Material Characteristics

1.Cast Steel Material Selection and Performance

2.Key Technical Parameters

Flow range: 30-300m³/h, suitable for 500-50,000-ton vessels

Head: 15-60m, meeting requirements for long-distance transportation of bilge water and lifting to overboard

Impurity passing capacity: Centrifugal pumps can pass ≤10mm solid particles; reciprocating pumps can pass ≤15mm fibrous impurities (e.g., ropes, rags)

Corrosion resistance design: Inner walls adopt epoxy resin + glass fiber composite coating (thickness ≥300μm), withstanding 10,000 hours of oil immersion without peeling

Temperature adaptability: Stable operation at -20℃~100℃, capable of handling high-temperature bilge water (e.g., engine room cooling water leakage)

3.Safety Performance

Equipped with overload protection devices, automatically shutting down when torque exceeds limits due to foreign objects to avoid pump damage

Explosion-proof motors comply with ATEX Zone 2 standards, suitable for flammable and explosive cabin environments such as oil tankers

III. Technical Advantages and Innovative Design

1. Anti-Clogging and Impurity Handling Capability

open impeller + cutting structure: Centrifugal pumps use serrated open impellers, capable of cutting fibrous impurities (e.g., plastic ropes, fishing nets) with diameters ≤8mm, reducing clogging rates by 90% and eliminating the need for frequent cleaning.

Self-priming design: Integrated vacuum priming device with self-priming height ≥8m, capable of starting when bilge water level is only 50mm, avoiding damage from "dry pumping."

2. Adaptability to Complex Media

Oil-water mixture transportation: Pump body flow channels adopt anti-cavitation design, capable of transporting mixed sewage with oil content ≤30% without air locking, maintaining transportation efficiency ≥85%.

Anti-inclination and vibration resistance: Pump body and base use rubber shock-absorbing pads with vibration values ≤4.0mm/s, ensuring stable water absorption and drainage when the ship heels 25° or trims 15°.

3. Long Service Life and Low Maintenance

Wear-resistant flow components: Impeller surfaces are overlaid with tungsten carbide alloy (2mm thickness) with hardness up to HRC65, 4 times more wear-resistant than ordinary cast steel, with a service life exceeding 50,000 hours

Quick-release structure: Pump cover and body use a snap-on connection, allowing disassembly in ≤15 minutes, facilitating cleaning of impurities in the suction chamber and improving maintenance efficiency by 60%.

IV. Typical Application Scenarios

1. Bilge Drainage for Cargo Ships and Oil Tankers

Removal of accumulated water in dry cargo holds: 100,000-ton bulk carriers are equipped with alloy cast steel bilge pumps with flow rates of 100-200m³/h and pressure of 2.5MPa, capable of quickly draining accumulated water from cargo holds caused by rain or leakage, operating stably even with sand content ≤3%.

Bilge treatment in oil tanker engine rooms: 300,000-ton VLCCs use explosion-proof bilge pumps with flow rates of 80-150m³/h, transporting oily bilge water to oil-water separators and cooperating with heating systems (oil temperature ≤60℃) to improve separation efficiency.

2. Passenger Ships and Special Vessels

Bilge drainage in passenger ship living areas: Cruise ships are equipped with low-noise cast steel bilge pumps (noise ≤70dB) with flow rates of 50-100m³/h, filtering hair, fabrics, and other impurities through filters to avoid pipeline clogging.

Removal of muddy water in engineering vessels: Dredgers use wear-resistant bilge pumps capable of passing ≤10mm sediment particles with flow rates of 150-300m³/h, adapting to high-sediment bilge water during dredging operations.

3. Emergency and Special Scenarios

Drainage for stranded ships: Portable diesel-driven cast steel bilge pumps with flow rates of 30-80m³/h and self-priming height of 6m are used to quickly reduce water levels in cabins when ships run aground and take on water.

Anti-freeze drainage for polar ships: Bilge pumps of polar research vessels adopt heating jacket designs, starting within 30 seconds in -30℃ environments to prevent bilge water from freezing and damaging the pump body.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Ship type: Alloy cast steel (WC6) explosion-proof type for oil tankers and engineering vessels; carbon cast steel (WCB) economical type for ordinary cargo ships and passenger ships

Drainage requirements: Configure flow rate at 1.5 times the maximum accumulated water volume in the bilge; for example, a 5,000m³ cabin capacity recommends a flow rate ≥150m³/h

Media characteristics: Cutting impellers for fibrous impurities; wear-resistant types for high sediment content; anti-cavitation types for oily sewage

2. Maintenance Key Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.1MPa), bearing temperature (≤75℃), and abnormal noise every 200 hours

Regular maintenance: Clean suction filters (precision ≤10mm) monthly; inspect impeller wear quarterly; replace mechanical seals annually

In-depth maintenance: Conduct water pressure tests (1.5 times the rated pressure) every 4 years, inspect pump bodies for cracks, and re-spray anti-corrosion coatings

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, and other institutions (including performance and safety tests)

Environmental requirements: Discharged water has an oil content ≤15ppm, meeting IMO anti-pollution discharge standards, with 100% recyclable pump body materials