Stainless Steel Gear Fuel Oil Pump

I. Product Definition and Principle

Stainless steel gear fuel oil pumps are positive displacement pumps that achieve fuel transportation through gear meshing volume changes, using austenitic/duplex stainless steel as the main material. The core structure consists of stainless steel driving gears, driven gears, and pump bodies, suitable for sulfur-containing/high-viscosity fuel media such as diesel, heavy oil, and biodiesel, enabling stable oil supply within the pressure range of 0.3-2.5MPa. The pump body adopts an all-welded stainless steel structure, combined with fluororubber or PTFE seals, meeting the anti-leakage and corrosion resistance requirements of fuel systems. It is widely used in marine fuel supply, industrial fuel boilers, and mobile power generation equipment.

II. Core Materials and Performance Adaptation

1.316 Stainless Steel (Medium-Sulfur Fuel Scenarios)

Chemical Properties: Contains 2-3% molybdenum, with an annual corrosion rate <0.01mm in diesel with sulfur content ≤0.5%, tensile strength ≥520MPa, and can withstand fuel temperatures of -40℃~120℃.

Application Scenarios: Marine main engine light diesel supply systems (e.g., 0# diesel, viscosity 3-8cSt), industrial gas turbine fuel pumps, resisting corrosion from sulfides and antioxidants in fuel.

2.316L Stainless Steel (Low-Sulfur Fuel/Welding Scenarios)

Improved Design: Carbon content ≤0.03%, enhanced intergranular corrosion resistance after welding, gear surface boronized (hardness HRC45-50), with a wear rate 30% lower than 316 stainless steel in ultra-low sulfur diesel with sulfur content ≤0.1%.

Typical Applications: Marine fuel systems after IMO 2020 sulfur restrictions, diesel auxiliary pumps for LNG-powered ships, transporting biodiesel blended fuels (blend ratio ≤20%).

3.Duplex Stainless Steel (2205/2507)

High-Strength Corrosion Resistance: Ferritic-austenitic duplex structure, pitting corrosion resistance index (PREN) ≥40, stress corrosion resistance 2 times higher than 316L in heavy oil with sulfur content 1-3%, tensile strength ≥620MPa, and can withstand 2.5MPa high-pressure fuel impact.

Special Scenarios: Heavy oil (viscosity 180-380cSt) supply pumps for ocean-going ships, sulfur-containing fuel transport pumps in refineries, resisting acidic substances (pH≤4) generated by fuel high-temperature cracking.

III. Technical Advantages and Application Limitations

Core Technical Advantages

1. Fuel Adaptability and Sealing Performance

316L stainless steel gears achieve a volumetric efficiency of 85%-90% in 300cSt heavy oil (preheated to 80℃), with a self-priming height ≥5m (diesel medium); fluororubber seals have a leakage of ≤10 drops/hour in 120℃ fuel, complying with API 610 standards.

2. Wear Resistance and Long-Life Design

Duplex stainless steel gears undergo ion nitriding treatment, with surface hardness HRC55-60, and a service life of 40,000 hours in fuel containing 0.1% solid impurities (such as metal debris from damaged fuel filters), 8 times that of cast iron gears.

3. Explosion-Proof and Safety Compliance

The pump body adopts an explosion-proof design (Ex d IIB T4 Gb), and the motor junction box explosion-proof rating meets ATEX certification, suitable for hazardous areas (Zone 1) near fuel tanks, with static grounding resistance ≤1Ω to prevent fuel friction-induced explosions.

Performance Limitations

1. High-Temperature and High-Viscosity Boundaries

When the fuel temperature of 316 stainless steel pumps >150℃, fuel carbonization causes gear wear to increase by 50%, requiring a cooling jacket; when transporting heavy oil with viscosity >500cSt (unpreheated), pump efficiency decreases by 20%, requiring an electric heating device (power configured as 1kW/100L/h flow).

2. Impurity Sensitivity

Gear meshing clearance is 0.05-0.1mm, sensitive to solid particles >30μm (such as sand and rust in fuel), requiring a 前置 double-barrel filter (filtration accuracy ≤10μm); stop for cleaning when impurity content >50mg/L.

3. Cost and Noise Control

Duplex stainless steel pumps cost 5-6 times more than cast iron pumps, with a 40% increase in weight (e.g., DN80 pump weighs about 35kg); noise ≥80dB during high-speed operation (>1800r/min), requiring a soundproof cover (noise reduction ≥15dB).

IV. Typical Application Scenarios

1. Marine Fuel Systems

Main Engine Heavy Oil Supply: Duplex stainless steel pumps transport 380cSt heavy oil for low-speed two-stroke main engines, configured with electric heating jackets (heating power calculated based on 30℃ fuel temperature rise), achieving stable oil supply under 1.6MPa pressure to meet the fuel pressure requirements of MAN B&W main engines.

Emergency Fuel Pumps: 316L stainless steel pumps serve as fuel supply equipment for marine emergency generators, started by hand pumps, providing at least 3 hours of fuel supply when the main power fails, complying with SOLAS convention requirements for emergency systems.

2. Industrial Fuel Transportation

Boiler Fuel Supply: 316 stainless steel pumps transport 0# diesel for industrial boilers converted from coal to fuel, with a flow rate of 5-50m³/h and pressure of 0.6-1.0MPa, combined with a PLC control system for constant pressure oil supply, meeting TSG G0001 Boiler Safety Technical Supervision Regulations.

Mobile Power Generation Equipment: Integrated into container-type diesel generator sets, 316L stainless steel pumps transport -10# diesel, started through a fuel preheater (power 5kW) in -20℃ environments to ensure field operation power supply.

3. Special Fuel Media

Biodiesel Mixed Transportation: 316L stainless steel pumps transport B20 biodiesel (20% vegetable oil + 80% diesel), resisting the swelling effect of fatty acid methyl esters on metals. Seals use FFKM perfluororubber, heat-resistant up to 200℃, preventing biodiesel oxidation and deterioration.

V. Usage and Maintenance Specifications

1. Fuel Pretreatment Requirements

Heavy oil must be preheated to viscosity ≤100cSt (corresponding temperature ~100-120℃) using electric heating or steam tracing; when diesel water content >0.5%, a 前置 water separator is required to avoid water emulsification causing gear corrosion (stainless steel has increased pitting risk in fuel with water content >1%).

2. Operation Monitoring Key Points

Real-Time Parameters: Monitor inlet and outlet pressure (fluctuation ≤±5%), bearing temperature (temperature rise ≤35℃), fuel temperature (not exceeding material tolerance), equipped with pressure transmitters (accuracy 0.5 class) and temperature sensors (PT100).

Abnormality Handling: When abnormal pump vibration (amplitude >0.08mm) or unusual noise is detected, stop the pump immediately to inspect gear meshing clearance (allowable wear ≤0.03mm) to avoid gear tooth breakage caused by fuel impurity jamming.

3. Safety and Compliance Requirements 

Marine pumps must pass CCS/ABS classification society certification, providing sulfur corrosion test reports for stainless steel materials (ASTM G35 standard, no pitting after 72-hour immersion); industrial pumps must comply with API 676 standards, with an explosion-proof rating not lower than Ex d IIB T4.

Fuel system grounding resistance ≤4Ω, using conductive gaskets between the pump body and pipelines to prevent static electricity accumulation causing fuel vapor explosions.