Stainless Steel Screw Lubricating Oil Pump

I. Product Overview

Stainless steel screw lubricating oil pumps feature high-precision screw meshing structures, using austenitic stainless steel (316/316L) or duplex stainless steel (2205) as the main material. Designed based on positive displacement transportation principles, they provide low-pulsation and high-pressure transportation solutions for viscous media such as lubricating oil, hydraulic oil, and gear oil. The screw profile adopts a 5:6 asymmetric tooth design (tri-screw pump) with a meshing clearance ≤0.03mm, enabling stable transportation of lubricating oil with viscosity 10-3000cSt under 0.3-4.0MPa pressure, with a volumetric efficiency of 90%-95%. They are suitable for precision lubrication systems, hydraulic stations, and high-cleanliness industrial scenarios.

II. Core Materials and Performance Adaptation

1.316 Stainless Steel (Conventional Lubricating Oil Scenarios)

Characteristics: Contains 2-3% molybdenum, corrosion rate <0.005mm/year in mineral lubricating oil (acid value ≤0.1mgKOH/g), tensile strength ≥520MPa, resistant to lubricating oil temperatures of -20℃~150℃. The screw surface is sprayed with tungsten carbide (coating thickness 50-80μm), hardness reaches HRC65-70, and oil sludge deposition wear resistance is 5 times higher than cast iron.

Applications: Machine tool spindle lubrication systems, industrial gearbox thin oil stations, transporting conventional lubricating oils such as L-HM hydraulic oil and L-CKC industrial gear oil, suitable for media with oil temperature ≤120℃ and low acid value.

2.316L Stainless Steel (Food-Grade/High-Cleanliness Lubrication)

Improved Design: Carbon content ≤0.03%, excellent intergranular corrosion resistance after welding, screw surface electrolytic polishing (Ra≤0.4μm), complying with FDA food contact standards. In synthetic lubricating oil (such as polyalphaolefin PAO), the wear rate is 30% lower than 316 stainless steel, suitable for lubricating oils containing extreme pressure additives (sulfur-phosphorus type).

Typical Scenarios: Lubricating oil transportation for food processing equipment (biscuit production lines, chocolate molding machines), hydraulic systems for pharmaceutical machinery, transporting white oil and food-grade lubricating oil (NSF H1 certified) to avoid media contamination.

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 gear oil containing sulfur extreme pressure additives (sulfur content >1%), tensile strength ≥620MPa, and can withstand 4.0MPa high-pressure lubrication system impact.

Special Applications: Hydraulic systems for metallurgical continuous casting machines (transporting anti-wear hydraulic oil with extreme pressure agents), gearbox lubrication for offshore engineering platforms (resisting humid salt spray environments), and resisting acidic substances (pH≤4) generated by high-temperature oxidation of lubricating oil.

III. Technical Advantages and Application Limitations

Core Technical Advantages

1. Low-Pulsation Transportation and High-Viscosity Adaptability

The spiral meshing of tri-screw pumps forms continuous sealing chambers, with outlet pressure pulsation ≤±1%, suitable for precision hydraulic systems (such as servo valve control). In lubricating grease with viscosity 3000cSt (preheated to 80℃), it still maintains 85% volumetric efficiency, with a self-priming height ≥5m (superior to gear pumps).

2. Long Life and Low-Noise Design

316L stainless steel screws undergo ion nitriding treatment (depth 0.2-0.3mm), surface hardness HRC55-60, service life reaches 80,000 hours in lubricating oil containing 0.1% solid impurities; operation noise ≤75dB (at 1500rpm), 10-15dB lower than gear pumps, suitable for workshop noise reduction requirements.

3. High Cleanliness and Explosion-Proof Safety

The pump body flow channel is mirror-polished (Ra≤0.8μm) to avoid lubricating oil carbonization and coking, suitable for high-cleanliness scenarios such as servo systems; equipped with bellows mechanical seal + PTFE lip seal double protection, leakage ≤3 drops/hour, motor explosion-proof grade Ex d IIB T4 Gb, suitable for combustible lubricating oil vapor environments.

Performance Limitations

1. High-Temperature and Impurity Sensitivity Boundaries

When the oil temperature of 316 stainless steel pumps >180℃, lubricating oil carbonization causes screw wear to increase by 50%, requiring a cooling jacket (heat exchange area ≥2m²). When transporting lubricating oil with particles >10μm, a double-barrel filter (accuracy ≤3μm) is required; otherwise, meshing clearance wear increases by 0.01mm monthly.

2. Viscosity and Speed Matching Limitations

When transporting low-viscosity lubricating oil with viscosity <10cSt (such as spindle oil), the speed should be controlled ≥2000rpm to avoid increased internal leakage; when viscosity >2000cSt (unpreheated), pump efficiency decreases by 30%, requiring a electric heating (power configured as 2kW/100L/h flow).

3. Cost and Installation Requirements

Duplex stainless steel pumps cost 8-10 times more than cast iron pumps, with a 60% increase in weight (e.g., DN80 pump weighs about 38kg), requiring a rigid foundation (levelness ≤0.1mm/m). Large-flow models (≥300L/min) need an inlet flow stabilizer to prevent cavitation (NPSHa≥3m).

IV. Typical Application Scenarios

1. Industrial Lubrication Systems

Precision Machine Tool Spindle Lubrication: 316L stainless steel tri-screw pump transports 32cSt spindle oil for five-axis machining centers, pressure 2.5MPa, flow 15L/min. Low-pulsation characteristics ensure uniform lubrication of spindle bearings, with temperature fluctuation ≤±2℃.

Wind Turbine Gearbox Lubrication: Duplex stainless steel pump transports synthetic gear oil with extreme pressure agents (viscosity 460cSt) for 3MW wind turbine gearboxes, configured with constant temperature control (40-60℃), started by electric heating in -30℃ low-temperature environments to ensure long-cycle operation of offshore wind power equipment.

2. Hydraulic and Power Systems

Metallurgical Equipment Hydraulic Stations: 316 stainless steel twin-screw pump transports L-HV low-temperature anti-wear hydraulic oil for rolling mill hydraulic systems, pressure 3.5MPa, flow 200L/min, resisting emulsification corrosion from trace water (≤0.05%) and air in hydraulic oil to meet continuous rolling conditions.

Construction Machinery Lubrication: Mining excavator central lubrication systems use 316 stainless steel pumps to transport calcium-based lubricating grease (viscosity 2000cSt), pressure 4.0MPa, controlled by PLC for timed and oil injection, adapting to dusty and vibrating environments.

3. Special Media and Environments

Food and Pharmaceutical Equipment: 316L stainless steel pump transports food-grade white oil (viscosity 100cSt) to biscuit production line chain lubrication points, surface electrolytic polishing (Ra≤0.2μm), complying with GMP certification requirements to avoid lubricating oil contamination of food raw materials.

Chemical Anti-Corrosion Scenarios: Duplex stainless steel pump transports chlorine-containing lubricating oil (chloride ion concentration ≤50ppm) in chemical reactor mixing systems, using fluororubber seals (FKM), heat-resistant up to 200℃, resisting chemical medium corrosion.

V. Usage and Maintenance Specifications

1. Lubricating Oil Pretreatment Requirements

High-viscosity lubricating oil must be preheated to viscosity ≤500cSt (corresponding temperature ~60-80℃), using electric heating jackets (power density ≤2W/cm²). Lubricating oil containing extreme pressure additives should have acid value controlled ≤0.3mgKOH/g, regularly tested (once every 3 months) to avoid acidic substance corrosion of stainless steel surfaces.

2. Operation Monitoring Key Points

Real-Time Parameters: Monitor inlet and outlet pressure (fluctuation ≤±5%), bearing temperature (temperature rise ≤35℃), lubricating oil temperature (not exceeding material tolerance), equipped with flow sensors (accuracy ±1%), and automatically cut off in case of abnormalities (such as flow drop ≥15%).

Regular Maintenance: Inspect screw meshing clearance every 2000 hours (allowable wear ≤0.015mm), replace mechanical seals every 10,000 hours (replace in advance when leakage >5 drops/hour). Lubricating oil replacement cycle should not exceed 6 months; when changing oil, clean the pump cavity with solvents (such as petroleum ether).

3. Safety and Compliance Requirements

Industrial pumps must comply with API 676 standards, explosion-proof grade not lower than Ex d IIB T4, static grounding resistance ≤4Ω. Food-grade pumps must provide NSF H1 certification and surface roughness test reports (Ra≤0.4μm), and stainless steel components in contact with media must pass intergranular corrosion tests (ASTM A262 E method).

Lubrication systems should have high-low pressure protection: low-pressure alarm value ≤0.2MPa (prevent oil shortage), high-pressure cut-off value ≥4.5MPa (prevent overpressure). The pump inlet should install magnetic filters (adsorbing iron filings), and the outlet should be equipped with safety valves (opening pressure 1.1 times working pressure).