Marine Cast Steel Fuel Oil Pump

I. Product Overview

Marine cast steel fuel oil pumps serve as the "core fuel delivery system" for ship power plants, specifically designed for inter-tank transfer, pressurization, and supply of marine fuels such as diesel oil, heavy fuel oil, and residual fuel oil. Constructed with high-strength alloy cast steel (WC6/WC9) or carbon cast steel (WCB), they achieve stable delivery of high-pressure, high-viscosity fuel oils through gear pump or piston pump principles. The working principle involves a power source driving gear meshing or piston reciprocation to generate volume changes, drawing fuel oil from storage tanks, pressurizing it, filtering it, and delivering it to the fuel injection systems of power equipment such as main engines and generators to ensure combustion efficiency and operational stability. The pump body undergoes integral forging and oil-resistant anti-corrosion treatment, with a corrosion-resistant service life of ≥10 years in fuel oils with temperatures ranging from -30°C to 150°C and sulfur content ≤5%. It meets the IMO MARPOL Annex VI fuel system specifications and certification requirements of classification societies such as LR and ABS, widely used in oil tankers, cargo ships, LNG carriers, and engineering vessels.

II. Core Technologies and Material Characteristics

1.Cast Steel Material Selection and Performance

2.Key Technical Parameters

Flow range: 10-300m³/h, suitable for main engine power 1000-30,000kW

Pressure range: Gear pumps 1.6-6.0MPa, piston pumps 4.0-10.0MPa, meeting pressure requirements of different injection systems

Medium compatibility: Capable of transporting diesel oil, heavy fuel oil, residual oil, and blended fuels with additives, with viscosity 5-2000cSt

Heating performance: Integrated steam jacket or electric heating device, capable of heating heavy fuel oil from ambient temperature to 80-120°C to reduce viscosity for delivery requirements

Temperature adaptability: Continuous operation at -30°C~150°C; low-temperature models can withstand -40°C startup

3.Safety and Explosion-Proof Design

Motor explosion-proof grade Ex d IIB T4, suitable for Zone 1 hazardous areas (near fuel oil tanks)

Leak detection and automatic shutdown device, immediately shutting down and alarming when fuel oil leakage ≥5mL/h

III. Technical Advantages and Innovative Design

1. High-Viscosity Fuel Oil Delivery Capability

Screw-gear composite structure: The suction section uses screw pump principles to enhance suction, while the discharge section uses gear pump pressurization, capable of delivering heavy fuel oil with viscosity up to 2000cSt without pre-dilution, with delivery efficiency ≥92%.

Gradient heating system: The pump body is independently heated in three sections (suction section 60°C, compression section 80°C, discharge section 100°C) to avoid local overheating causing fuel oil cracking, reducing energy consumption by 25%.

2. Extreme Condition Reliability

Anti-cavitation and anti-air locking: A spiral inducer is installed at the inlet to reduce the net positive suction head (NPSH) by 40%, avoiding cavitation in low liquid level or high-temperature fuel oil; a built-in exhaust valve automatically removes air from the fuel oil to prevent air locking.

Vibration and inclination resistance: The pump body and base use elastic shock absorbers, with vibration value ≤3.0mm/s, ensuring stable operation even when the ship heels 30° transversely or trims 15° longitudinally, meeting requirements for harsh sea conditions.

3. Long Life and Low Maintenance

Wear-resistant friction pair: Gears/pistons use nitrided alloy cast steel (38CrMoAlA), with surface hardness up to HV900, 6 times more wear-resistant than ordinary cast steel, and trouble-free operation cycle exceeding 60,000 hours.

Modular quick-repair design: The pump core and drive end use flange quick connections, allowing replacement of wearing parts without disassembling pipelines, with single maintenance time ≤2 hours, 70% shorter than traditional structures.

IV. Typical Application Scenarios

1. Main Engine Fuel Oil Supply

Heavy fuel oil supply for low-speed diesel engines: 150,000-ton cargo ship main engines are equipped with WC6 alloy cast steel piston pumps, with flow 50-150m³/h and pressure 8.0MPa, cooperating with a heating system to heat heavy fuel oil to 100°C to meet the high-pressure injection requirements of main engines.

Light diesel oil supply for high-speed diesel engines: Passenger ship gas turbines are matched with gear-type fuel oil pumps, with flow 10-50m³/h and pressure 4.0MPa, providing high-pressure atomized diesel oil to the combustion chamber with a response time ≤0.5 seconds.

2. Fuel Oil Inter-Tank Transfer

Heavy fuel oil storage tank-service tank transfer: Oil tankers use twin-screw fuel oil pumps, with flow 100-300m³/h and pressure 6.0MPa, capable of completing inter-tank transfer of 500m³ heavy fuel oil within 3 hours with full-temperature control.

Emergency diesel oil supply: Cargo ship emergency generators are equipped with self-priming cast steel fuel oil pumps, with self-priming height ≥6m and flow 10-30m³/h, ensuring quick switching to emergency fuel oil tanks in case of main fuel supply system failures.

3. Special Vessels and Platforms

Low-temperature fuel oil delivery for polar ships: In -35°C environment, through pump body insulation and fuel oil preheating design, ensuring light diesel oil does not solidify at low temperatures, with pump body startup time ≤30 seconds to supply fuel to icebreaker main engines.

Power generation units for drilling platforms: Offshore platform power generation units use high-temperature fuel oil pumps, operating stably under 120°C heavy fuel oil conditions, with flow 20-80m³/h and pressure 5.0MPa.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Fuel oil type: Alloy cast steel piston pumps (with heating) for heavy fuel oil/residual oil, carbon cast steel gear pumps for diesel oil

Main engine power: Configure according to 1.2 times the main engine fuel consumption rate of 180g/kW·h; for example, 10,000kW main engines recommend flow ≥2160m³/h (Note: The unit here should be m³/d, which may be a typo in the original text and needs conversion for actual hourly calculation)

Environmental conditions: Sulfur-resistant alloy cast steel (WC9) for high-sulfur fuel oil, -40°C startup type for cold regions, forced cooling type for tropical regions

2. Maintenance Key Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.2MPa), oil temperature (≤150°C), and vibration value (≤3.5mm/s) every 400 hours

Regular maintenance: Clean fuel oil filters (precision ≤20μm) monthly, calibrate heating temperature (deviation ≤±5°C) quarterly, replace mechanical seals (material: silicon carbide-nickel-based alloy) annually

In-depth maintenance: Disassemble and inspect gear/piston wear (dimensional deviation ≤0.05mm) every 5 years, re-grind the mating surface, and test pressure stability

VI. Compliance and Certification

International standards: Complies with IMO MARPOL Annex VI and MEPC.321(74) fuel system emission requirements

Classification society certifications: Passed type approval for fuel oil pumps by LR, ABS, CCS, and other institutions (including explosion-proof and pressure tests)

Environmental requirements: Pump body materials 100% recyclable, lubricants using biodegradable types, meeting IMO anti-pollution requirements