Marine Screw Lubricating Oil Pump

I. Product Overview

Marine screw lubricating oil pumps are the "precision core" of lubrication guarantees for ship power systems, designed specifically for high-pressure lubricating oil circulation in equipment such as diesel engines, gearboxes, and turbochargers. Through volumetric changes generated by screw meshing, they continuously deliver high-pressure lubricating oil films to mechanical friction pairs (bearings, gear tooth surfaces) to reduce wear and dissipate heat. Constructed with alloy cast iron (HT350), bronze alloy (ZCuAl10Fe3), or stainless steel (316L) as the main material, they rely on the synchronous rotation of two or three screws to form closed chambers, drawing medium from lubricating oil tanks, pressurizing it, and delivering it directly to various lubrication points via pipelines. The pump body undergoes precision machining and anti-corrosion treatment, with a service life of ≥10 years in -30℃~120℃ environments. It meets IMO Guidelines for Ship Machinery Lubrication Systems (MSC.1/Circ.1234) and lubrication equipment certification requirements of classification societies such as RS, LR, ABS, and CCS, widely used in high-load power equipment lubrication systems of large oil tankers, container ships, passenger ships, and other vessels.

II. Core Technologies and Material Characteristics

1.Material Selection and Performance

2.Key Technical Parameters

Flow range: 1-50m³/h, suitable for equipment power 5000-50,000kW (e.g., 20,000kW main engines require flow ≥8m³/h)

Pressure coverage: 1.6-5.0MPa, meeting pressure requirements for transportation from tanks to high-pressure lubrication points (including filter and cooler resistance losses)

Medium compatibility: Capable of conveying mineral lubricating oil (viscosity 30-1000cSt), synthetic lubricating oil (PAO/ester), extreme pressure gear oil (EP grade), and lubricating media with temperature -30℃~120℃

Self-priming performance: Self-priming height ≥2.5m, priming time ≤40 seconds, suitable for oil suction from low-level tanks without manual oil filling

Volumetric efficiency: ≥97% under design conditions, 2% higher than gear pumps; maintains ≥90% efficiency in high-viscosity (800cSt) media

3.Safety and Precision Design

Pressure closed-loop control: Equipped with pressure sensors and variable frequency motors to adjust screw speed in real-time, ensuring outlet pressure stabilizes within ±0.1MPa of the set value and avoiding pressure fluctuations at lubrication points

Impurity interception system: Inlet fitted with 5μm high-precision filters, cooperating with screw tip clearance (≤0.02mm) to intercept metal debris and sludge, protecting friction pairs from particle wear

Low-pulsation structure: Three-screw meshing "continuous chamber" design achieves a flow pulsation rate ≤3%, 80% lower than gear pumps, avoiding vibration fatigue in high-pressure pipelines

III. Technical Advantages and Innovative Design

1. High-Pressure and High-Viscosity Medium Conveying Capacity

Three-head screw structure: Uses a three-head meshing design with a driving screw and two driven screws, improving volumetric efficiency by 5% compared to twin-screw pumps. In extreme pressure gear oil with 1000cSt viscosity, outlet pressure remains stable at 4.0MPa.

Temperature adaptive adjustment: Pump bodies integrate temperature sensors, automatically increasing screw speed by 15% when lubricating oil viscosity rises due to low temperatures (e.g., reaching 1000cSt at -30℃) to ensure stable flow.

2. Wear Resistance and Corrosion Resistance Enhancement

Screw surface hardening: Alloy cast iron screws undergo nitriding treatment, achieving surface hardness HV800, improving anti-seizure performance by 60% compared to ordinary cast iron, and extending service life to 15,000 hours in lubricating oil containing trace impurities.

Stainless steel flow channel optimization: 316L flow components undergo electrolytic polishing (Ra≤0.4μm) to reduce carbon deposition from high-temperature lubricating oil, extending cleaning intervals to 800 hours and reducing maintenance frequency by 50% compared to ordinary pumps.

3. Adaptability to Ship Operating Conditions

Impact-resistant structure: Pump units and bases adopt rubber shock absorbers + spring composite buffering, with flow attenuation ≤3% under ship heel ±25° and trim ±15°, ensuring uninterrupted lubrication in severe sea conditions.

Compact design: 40% smaller in volume than gear pumps of the same flow, with a single unit weight ≤300kg, suitable for installation in narrow engine rooms and supporting both vertical and horizontal mounting methods.

IV. Typical Application Scenarios

1. Main Engine and Gearbox Lubrication

Low-speed diesel engine lubrication: 30,000kW low-speed main engines are equipped with stainless steel screw lubricating oil pumps (flow 10-15m³/h, pressure 4.0MPa) to deliver 46-grade extreme pressure lubricating oil to crankshaft main bearings, maintaining stable oil supply pressure at 3.5±0.1MPa and ensuring bearing temperature ≤70℃.

Reduction gearbox lubrication: Container ship main gearboxes use bronze alloy screw pumps (flow 5-8m³/h, pressure 3.0MPa) to deliver 150-grade gear oil to meshing tooth surfaces, forming an oil film ≥8μm thick and controlling tooth surface wear rate within 0.005mm/1000 hours.

2. High-Speed Equipment and Special Equipment Lubrication

Turbocharger lubrication: 20,000r/min high-speed turbochargers are equipped with miniature stainless steel screw pumps (flow 0.8-1.2m³/h, pressure 4.5MPa) to deliver 32-grade turbine oil to floating bearings, ensuring a lubricating oil film ≥3μm thick and avoiding bearing burnout during high-speed operation.

Stern tube lubrication: Large oil tanker stern tubes use alloy cast iron screw pumps (flow 2-3m³/h, pressure 2.0MPa) to deliver lubricating grease with 400cSt viscosity, forming a sealing oil film during shaft rotation to reduce seawater intrusion.

3. Extreme Environment Adaptation

Polar low-temperature lubrication: In -30℃ environments, screw pumps with heating jackets (2kW power) heat low-temperature lubricating oil (800cSt viscosity) to 40℃ (viscosity reduced to 150cSt), maintaining flow at 2-5m³/h and ensuring proper lubrication during research vessel main engine startup.

Tropical high-temperature lubrication: In 45℃ engine room environments, stainless steel screw pumps deliver 68-grade high-temperature lubricating oil to diesel generators at 4-6m³/h. The pump body's heat dissipation design controls oil temperature at 60±3℃, preventing oxidative deterioration of lubricating oil.

V. Selection and Maintenance Specifications

1. Key Selection Parameters

Equipment type: Alloy cast iron/stainless steel pumps for low-speed diesel engines and gearboxes; bronze alloy pumps for high-speed turbochargers

Flow calculation: Configure 1.3 times the total oil consumption of equipment lubrication points; e.g., a gearbox consuming 0.6m³/h requires flow ≥0.78m³/h

Pressure requirements: 1.6-3.0MPa for ordinary bearing lubrication; 3.0-5.0MPa for high-pressure gear tooth surfaces; heating-equipped models for extremely cold environments

2. Maintenance Points

Daily monitoring: Check outlet pressure (fluctuation ≤±0.05MPa), screw shaft temperature (≤80℃), and mechanical seal leakage (≤0.5mL/h) every 500 hours

Regular maintenance: Clean inlet filters monthly; replace mechanical seals (oil-resistant fluoroelastomer) every 2000 hours; inspect screw clearance (maximum allowable 0.05mm) every 8000 hours

Oil quality management: Test lubricating oil viscosity changes (≤15%) and water content (≤0.1%) every 3 months; replace oil promptly if exceeding standards to avoid corrosion of pump internal components

3. Compliance Inspection

Annual classification society inspection, focusing on verification of volumetric efficiency (≥92%), pressure stability, and compatibility with lubrication systems

Meets IMO requirements for ship machinery lubrication, ensuring equipment friction pair temperatures do not exceed design limits (e.g., diesel engine piston pin temperature ≤180℃)

VI. Compliance and Certification

International standards: Complies with ISO 12151 marine screw pump performance standards and IMO MSC.1/Circ.1234 lubrication system guidelines

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

Material compliance: Flow-through components meet ASTM A48 (alloy cast iron), ASTM B148 (bronze alloy), and ASTM A240 (316L stainless steel) standards