Marine Screw Fuel Pump

I. Product Overview

Marine screw fuel pumps are the "efficient core" of fuel supply in ship power systems, designed specifically to deliver fuels such as diesel, heavy oil, and residual oil to equipment like diesel engines and gas turbines. Through volumetric changes in closed chambers formed by screw meshing, they achieve high-pressure, stable fuel delivery, ensuring sufficient combustion and stable power output. Constructed with cast iron (HT200), bronze alloy (ZCuSn10Pb2), or stainless steel (316L) as the main material, they rely on the synchronous rotation of two or three screws to generate suction and pressure, drawing medium from fuel tanks, pressurizing it, and delivering it directly to injectors or burners after filtration. The pump body undergoes precision machining and anti-corrosion treatment, with a corrosion-resistant service life of ≥8 years in -20℃~150℃ environments. It meets IMO Ship Fuel System Safety Specifications (MSC.285(86)) and fuel pump certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in high-pressure fuel supply systems of oil tankers, container ships, bulk carriers, and other vessels.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 2-100m³/h, suitable for equipment power 1000-50,000kW (e.g., 20,000kW main engines require flow ≥20m³/h)

Pressure coverage: 1.0-5.0MPa, meeting high-pressure delivery requirements from fuel tanks to injectors (including pipeline and filter resistance losses)

Medium compatibility: Capable of conveying light diesel (viscosity 8-20cSt), heavy diesel (viscosity 20-100cSt), heavy oil (viscosity 100-1000cSt, requiring heating), and fuel with temperature -20℃~150℃

Self-priming performance: Self-priming height ≥3m, priming time ≤50 seconds, suitable for oil suction from low-level fuel tanks without manual oil filling

Volumetric efficiency: ≥96% under design conditions, 3% higher than gear pumps of the same specification; maintains ≥90% efficiency in high-viscosity (800cSt) heavy oil

3.Safety and Explosion-Proof Design

Explosion-proof certification: Motors adopt Ex d IIB T4 Gb explosion-proof grade, suitable for Zone 1 hazardous areas near fuel tanks to prevent safety risks from oil and gas leakage

Overpressure protection: Safety valves automatically relieve pressure (returning oil to fuel tanks) when outlet pressure exceeds 1.2 times the rated value, avoiding pipeline burst

Precision filtration system: Inlet fitted with 10μm filters, cooperating with screw tip clearance (≤0.03mm) to intercept metal particles and sludge, protecting injectors

III. Technical Advantages and Innovative Design

1. High-Viscosity Fuel Conveying Capacity

Twin-screw meshing structure: Uses a double-helix meshing design with a driving screw and driven screw to form continuous closed chambers. In heavy oil with 1000cSt viscosity, pressure fluctuation ≤±0.05MPa, with pulsation 80% lower than gear pumps.

Integrated heating jacket: Pump bodies are wrapped with steam heating jackets (working pressure 1.0MPa), capable of heating heavy oil from ambient temperature (1000cSt viscosity) to 80℃ (viscosity reduced to 100cSt), ensuring fuel fluidity in low-temperature environments.

2. Wear and Corrosion Resistance Enhancement

Screw surface hardening: Stainless steel screws undergo nitriding treatment, achieving surface hardness HV700, improving resistance to sulfur corrosion in fuel by 50%, and extending service life to 12,000 hours.

Bronze pump anti-adhesion design: Bronze alloy screw tooth surfaces undergo mirror polishing (Ra≤0.8μm), reducing heavy oil colloid adhesion, extending cleaning intervals to 600 hours, and reducing maintenance frequency by 40% compared to ordinary screw pumps.

3. Adaptability to Ship Operating Conditions

Vibration-resistant structure: Pump units and bases adopt rubber shock absorbers + spring composite damping, with vibration values ≤3.0mm/s, ensuring stable operation in high-vibration main engine room environments (flow fluctuation ≤2%).

Compact design: 30% smaller in volume than gear pumps of the same flow, with a single unit weight ≤400kg, suitable for installation in narrow engine rooms and supporting both vertical and horizontal mounting.

IV. Typical Application Scenarios

1. Main Engine and Auxiliary Engine Fuel Supply

Low-speed diesel engine fuel supply: 30,000kW low-speed main engines are equipped with stainless steel screw fuel pumps (flow 30-50m³/h, pressure 4.0MPa) to deliver heavy oil heated to 120℃ (150cSt viscosity) to injectors, maintaining stable fuel supply pressure at 3.5±0.1MPa and ensuring atomized particle diameter ≤50μm.

Diesel generator fuel supply: 2000kW generators use cast iron screw pumps (flow 3-5m³/h, pressure 1.6MPa) to deliver light diesel to fuel injection pumps, with flow response time ≤1 second during generator load changes to ensure stable combustion.

2. Special Fuel Conveyance

High-sulfur heavy oil conveyance: Ocean-going oil tankers use stainless steel screw pumps (flow 20-30m³/h) to deliver heavy oil with 3.5% sulfur content, heated to 100℃ via heating jackets to reduce viscosity to 100cSt, operating continuously for 1000 hours without leakage and showing no pump body corrosion.

Polar low-temperature fuel supply: In -30℃ ice zone navigation, screw pumps with heating jackets (3kW power) convey -20℃ low-sulfur diesel (with 3% anti-freeze additives), heating oil temperature to 10℃ (15cSt viscosity) within 3 minutes, maintaining flow 5-10m³/h and ensuring startup of research vessel main engines.

3. Inter-tank Fuel Transfer

Fuel tank balancing: When large oil tankers need to adjust fuel tank positions during navigation, bronze alloy screw pumps (flow 15-20m³/h, pressure 2.0MPa) transfer fuel via cross-tank pipelines, completing 500m³ fuel transfer within 30 minutes to ensure ship stability.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Fuel type: Cast iron/bronze pumps for light diesel; stainless steel pumps for heavy oil and high-sulfur oil

Flow calculation: Configure 1.3 times the maximum fuel consumption of main engines; e.g., a main engine consuming 5m³/h requires flow ≥6.5m³/h

Pressure requirements: 3.0-5.0MPa for low-speed engines and heavy oil systems; 1.6-3.0MPa for medium-speed engines and light diesel

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.1MPa), bearing temperature (≤80℃), and mechanical seal leakage (≤3mL/h) every 600 hours

Regular maintenance: Replace mechanical seals (oil-resistant fluoroelastomer) and clean inlet filters every 2000 hours; inspect screw clearance (maximum allowable 0.08mm) every 8000 hours

Fuel switching maintenance: Flush pump chambers with light diesel before conveying different grades of fuel to avoid mixing contamination; fill pumps with anti-rust oil during long-term shutdown

3. Compliance Inspection

Annual classification society inspection, focusing on verification of volumetric efficiency (≥90%), explosion-proof performance, and compatibility with fuel systems

Meets IMO MARPOL Annex I requirements for fuel systems, ensuring fuel leakage rate ≤0.05% and compliance with environmental emission regulations

VI. Compliance and Certification

International standards: Complies with ISO 8661 marine screw pump performance standards and IMO MSC.285(86) fuel system safety guidelines

Classification society certifications: Obtained type approval for screw fuel pumps from RS, LR, ABS, and CCS (including 3000-hour heavy oil operation tests)

Environmental requirements: Compatible with low-sulfur fuel, meeting IMO 2020 global sulfur emission limits (≤0.5%)