Marine Cast Iron Centrifugal Bilge Pump

I. Product Overview

The marine cast iron centrifugal bilge pump is a core drainage equipment in the ship's safety guarantee system, specifically designed for removing bilge water (mixed water containing seawater, oil stains and a small amount of impurities) from ships. Its core function is to quickly and efficiently discharge bilge water from cargo holds, engine rooms, ballast tanks and other areas, preventing risks such as reduced stability, structural corrosion or sinking of the ship due to excessive water accumulation, and ensuring the safety of ship navigation and berthing. This equipment adopts high-quality HT200 gray cast iron to manufacture core components such as the pump body, impeller and pump cover, matched with oil-resistant and corrosion-resistant sealing assemblies and reinforced transmission shafts. It has the characteristics of sturdy structure, impact resistance and cost-effectiveness. At the same time, relying on the high-flow delivery advantage of centrifugal pumps, it can adapt to working conditions such as high humidity, salt spray, vibration and complex bilge water media faced by various ocean-going and coastal ships.

As an essential emergency safety equipment for ships, the marine cast iron centrifugal bilge pump strictly complies with international and domestic standards such as the International Convention for the Safety of Life at Sea (SOLAS), IMO Marine Machinery Equipment Rules, GB/T 10832-2011 *Marine Pumps* and GB/T 3216-2005 *Rotodynamic Pumps - Hydraulic Performance Acceptance Tests - Grades 1 and 2*. It has obtained certifications from mainstream classification societies such as China Classification Society (CCS) and American Bureau of Shipping (ABS), and is widely used in various ships including 500-100,000-ton ocean-going cargo ships, oil tankers, passenger ships, container ships, coastal fishing boats, inland water transport ships and offshore operation platforms. Compared with stainless steel and copper bilge pumps, cast iron achieves cost optimization through mature casting technology. At the same time, through targeted anti-rust and sealing design, it can meet the basic needs of bilge water delivery, making it the preferred bilge drainage equipment for small and medium-sized ships and ships sailing under normal conditions, and building a solid "drainage line of defense" for ship safety.

II. Core Technical Parameters

Flow Range: 5-300 m³/h, which can be customized in grades according to ship tonnage, bilge volume and drainage efficiency requirements. The flow stability error under rated working conditions is ≤±3%, ensuring rapid discharge of bilge water and avoiding water accumulation.

Pressure Range: 0.4-2.5 MPa, with a maximum working pressure of up to 3.0 MPa. It can meet the pressure requirements of multi-layer cabins and long-distance drainage pipelines, ensure the smooth flow of accumulated water in complex pipeline layouts, and adapt to the cabin structures of different ships.

Medium Compatibility: It can stably transport bilge water containing a small amount of impurities (seawater, fresh water, oil-stained mixed water); suitable for medium viscosity range of 1-100 mm²/s, impurity content ≤0.5% (particle size ≤3mm); applicable medium temperature range is -15℃ to 100℃, which can meet the needs of navigation in low-temperature sea areas and discharge of high-temperature accumulated water in engine rooms.

Material Parameters: The pump body, impeller and pump cover are made of HT200 gray cast iron (surface painted for rust prevention); the transmission shaft is made of steel (surface chrome-plated for rust prevention); the seals are made of fluororubber (FKM) or nitrile rubber (NBR), which have good compatibility with bilge water (including oil stains) and ensure no leakage, no corrosion during long-term operation.

Drive Mode: Mainly adopts marine motor drive (three-phase asynchronous motor, protection class IP55), with optional diesel engine drive mode; the motor supports marine standard voltages of 220V/380V, and the drive system is equipped with overload, overheating and phase loss protection functions, which can be linked with the ship's central control system to realize automatic start and stop.

Operating Performance: Self-priming height ≥3 m, self-priming time ≤40 seconds (at a suction lift of 2m); volumetric efficiency ≥85%, operating noise ≤78 dB(A), vibration acceleration ≤1.2 m/s²; continuous operation life ≥6000 hours, which can meet the needs of long-term continuous work in emergency drainage scenarios.

III. Structural Design and Core Advantages

3.1 Core Structural Design

Integrated Cast Iron Centrifugal Structure: The pump body and pump cover are formed by integral casting process, without spliced welds, with compact and sturdy structure and excellent impact resistance, which can withstand the during ship navigation and the impact load during emergency drainage; the impeller adopts a closed cast iron impeller, calibrated by dynamic balance, with stable operation. The optimized flow channel design is suitable for the characteristics of bilge water containing a small amount of impurities, effectively reducing the risk of blockage.

Reinforced Sealing and Anti-Leakage System: Adopts a dual-seal structure of "mechanical seal + O-ring". The sealing surface is made of alumina-graphite composite material, which specifically solves the impact of oil stains and salt in bilge water on sealing performance, with a leakage rate ≤0.005 mL/h; equipped with a waterproof and dustproof protective cover for the seal chamber to avoid damage to the seal assembly by bilge debris.

Anti-Vibration and Wear-Resistant Protection Design: The exterior of the pump body adopts a cast iron protective shell, combined with a reinforcing rib structure to improve overall rigidity; the base is made of cast iron and equipped with rubber shock-absorbing pads to effectively buffer operating vibration and avoid resonance with the hull structure; the inlet and outlet pipelines are equipped with flexible joints to reduce the impact of pipeline vibration on the pump body.

Simple Emergency Control Module: Equipped with a standardized emergency control box, supporting manual/automatic dual-start mode, which can be linked with the ship's bilge water level sensor to realize automatic start of drainage when the water level exceeds the standard; the control panel has a simple layout and clear labeling, equipped with simple flow and pressure indicators and fault alarm lights, facilitating quick operation and fault diagnosis by the crew.

3.2 Core Technical Advantages

Cost-Effective and Durable: HT200 gray cast iron has easily available raw materials and mature casting technology. Compared with stainless steel bilge pumps, the purchase cost is reduced by 40%-60%, and the price of maintenance parts is low; cast iron has excellent impact resistance and wear resistance, adapting to the complex and bumpy working conditions of ships, with a long service life, greatly reducing the purchase and operation and maintenance costs of ship equipment, and meeting the economic needs of small and medium-sized ships.

Adaptable to Complex Bilge Media: Designed for the characteristics of bilge water containing seawater, oil stains and a small amount of impurities, the cast iron pump body is painted for rust prevention, combined with oil-resistant and corrosion-resistant seals, which can effectively resist salt spray erosion and oil corrosion; the optimized flow channel and closed impeller design can smoothly transport accumulated water containing impurities with particle size ≤3mm, not easy to block, ensuring continuous drainage.

Stable Operation and Efficient Drainage: Relying on the high-flow delivery characteristics of centrifugal pumps, it can quickly discharge bilge water, avoiding safety hazards caused by water accumulation; it has strong self-priming capacity, no additional priming is needed, and can quickly start drainage in emergency situations; low operating noise and small vibration, without affecting the normal navigation of the ship and the working environment of the crew.

Convenient Maintenance and Simple Operation: Key components adopt modular design, and wearing parts such as impellers and seals can be quickly disassembled and replaced with simple tools, without professional maintenance skills; daily maintenance only needs to regularly clean the inlet filter screen, check the sealing status and add lubricating oil, with a long maintenance cycle (regular maintenance interval ≥3 months), reducing the maintenance workload of the crew.

Safe, Compliant and Widely Adaptable: Strictly follows international and domestic ship safety standards, and has passed multiple rigorous tests by classification societies (pressure test, leakage test, vibration test, high and low temperature operation test, etc.); adapts to the bilge drainage systems of various 500-100,000-ton ships, and supports simple customization according to the specific cabin layout and drainage needs of the ship, with strong adaptability.

IV. Typical Application Scenarios

4.1 Bilge Drainage for Ocean-Going Cargo Ships/Oil Tankers

Ocean-going cargo ships and oil tankers have long navigation distances and large cabin volumes, and bilge water mixed with seawater, cargo oil residues and rainwater is likely to accumulate at the bilge, requiring high reliability and drainage efficiency of bilge pumps. The marine cast iron centrifugal bilge pump can quickly discharge accumulated water from various cargo holds and engine rooms. The impact resistance of cast iron adapts to the bumpy working conditions of ocean-going navigation, and the oil-resistant sealing design can resist corrosion from cargo oil residues, ensuring the safety and stability of long-term ocean-going navigation of the ship.

4.2 Cabin Drainage for Passenger Ships/Ferries

Passenger ships and ferries carry a large number of passengers, and bilge water is directly related to the safety of passengers and the ship, requiring strict requirements on the operational stability and safety of bilge pumps. The marine cast iron centrifugal bilge pump has low operating noise and small vibration, which can ensure the comfort of passengers; the automatic start-stop function can realize timely drainage when the water level exceeds the standard, and the dual-seal structure avoids water leakage, providing a reliable guarantee for the navigation safety of passenger ships.

4.3 Bilge Drainage for Coastal Fishing Boats/Small Operation Ships

Coastal fishing boats and small operation ships have complex navigation environments and limited maintenance conditions, requiring high cost-effectiveness and durability of bilge pumps. The marine cast iron centrifugal bilge pump is low-cost and easy to maintain, can adapt to the high salt spray and strong vibration environment of coastal areas, quickly discharge bilge water formed by wave influx and rainwater accumulation, ensure the navigation safety of small 

hips, and reduce equipment use costs.

4.4 Emergency Drainage for Special Ships (Icebreakers, Scientific Research Vessels)

Icebreakers and scientific research vessels often navigate in low-temperature sea areas such as polar and frigid zones, and bilge water mixed with melted snow and seawater is likely to accumulate at the bilge. The marine cast iron centrifugal bilge pump has excellent low-temperature starting performance (can start normally at -15℃), and the low-temperature resistance and impact resistance of cast iron can adapt to extreme navigation conditions. It has strong emergency drainage capacity, providing a guarantee for the navigation safety of special ships in extreme environments.

4.5 Bilge Drainage for Coastal Operation Platforms

Operation platforms such as coastal drilling platforms and aquaculture platforms face high salt spray and high humidity environments, and seawater and rainwater are likely to accumulate at the bilge. The anti-rust protection design and dual-seal system of the marine cast iron centrifugal bilge pump can effectively resist salt spray erosion, stably discharge accumulated water at the platform bilge, and ensure the structural safety of the platform and the personal safety of operators.