Lubricated Rotary Screw Compressor – Efficient, Reliable, and Cost-Effective Industrial Air Power

Product Overview

The lubricated rotary screw compressor represents the most widely used compressed air technology in general industry – and for good reason. By injecting oil into the compression chamber, these compressors achieve levels of efficiency, reliability, and longevity that make them the practical choice for manufacturing, automotive, food processing, and countless other applications where instrument-quality air is not required.

How Oil-Flooded Technology Works

In a lubricated rotary screw compressor, oil serves multiple critical functions:

Sealing: Oil fills the microscopic clearances between rotors and housing, preventing air from leaking back through the compression chamber. This sealing action is the key to screw compressor efficiency – without oil, internal leakage would reduce output by 30–50%.

Cooling: Compression generates heat – lots of it. Oil absorbs this heat as it circulates through the compressor, carrying it away to an oil cooler. This cooling action keeps discharge temperatures moderate and prevents thermal damage to components.

Lubrication: Bearings, rotors, and seals all require continuous lubrication. The oil system delivers filtered oil to every moving part, ensuring long life and reliable operation.

The Result: A compressor that delivers more air per horsepower, runs cooler, and lasts longer than any alternative for general industrial use.

Precision-Engineered Components

Rotors – The Heart of the Compressor:

• Forged steel rotors with precision-ground profiles

• Asymmetric rotor design optimizes sealing line for maximum efficiency

• Hardened surfaces (58–62 HRC) resist wear for decades of service

• Manufacturing tolerances: 0.001–0.003 inches – measured in microns

• Dynamic balancing ensures smooth, vibration-free operation

Bearing System:

• Heavy-duty roller bearings on discharge end handle radial loads

• Deep-groove ball bearings on inlet end accommodate thrust

• Bearing life: L10 100,000+ hours (11+ years continuous operation)

• Oil-cooled for extended life under all conditions

Sealing System:

• Non-contacting labyrinth seals on rotor shafts

• Oil injection creates dynamic seal during operation

• Stationary seals prevent leakage when stopped

• All seals replaceable without major disassembly

Lubrication System – The Lifeline

Oil Circulation:

1. Oil is injected into compression chamber through multiple ports

2. Mixes with air, sealing clearances and absorbing heat

3. Exits with compressed air into oil separator tank

4. Primary separation removes 99% of oil

5. Oil passes through cooler and filter

6. Returns to injection points – continuous cycle

Oil Specifications:

• Type: Synthetic hydrocarbon or diester-based

• Viscosity: ISO VG 46 or 68 typical

• Change interval: 4,000–8,000 hours (synthetic)

• Capacity: Sized for continuous operation at rated output

Drive System Options

Direct Drive:

• Motor shaft connects directly to compressor rotor via flexible coupling

• 100% power transfer – no transmission losses

• No belts to tension or replace

• No pulley alignment issues

• Quieter operation

• Ideal for continuous, high-speed operation

Belt Drive:

• Motor mounted separately, connected by precision-matched belts

• Speed adjustment possible via pulley change

• Lower initial cost

• Motor isolation reduces vibration transmission

• Suitable where future flow changes may be needed

Variable Frequency Drive (VFD):

• Automatically adjusts motor speed to match air demand

• Speed range: 25–100% of rated

• Energy savings: 20–35% in variable-demand applications

• Precise pressure control: ±0.15 bar

• Soft start eliminates current spikes

• Power factor: >0.95 across speed range

Cooling System Options

Air-Cooled:

• Fin-tube coolers (aluminum fins, copper tubes)

• Thermostatically controlled fans maintain optimal temperature

• Design ambient: 100°F (38°C) standard, higher available

• No water required – simplifies installation

• Ideal for facilities without cooling water infrastructure

Water-Cooled:

• Shell and tube or plate heat exchangers

• Lower operating temperatures in high-ambient environments

• Stable performance year-round

• Heat recovery potential (up to 80% of input power)

• Smaller footprint than air-cooled

Temperature Control:

• Thermostatic bypass valve maintains minimum oil temperature

• Prevents condensation during light load periods

• Optimizes oil viscosity for bearing protection

• Ensures reliable operation in all conditions

Control & Monitoring Systems

Standard Control Features:

• Pressure switch with adjustable setpoints

• Load/unload operation with minimum pressure band

• Automatic start/stop based on system pressure

• Safety shutdowns (high temperature, low oil pressure)

• Hour meter for maintenance tracking

• Fault indication lights

Advanced PLC Control:

• Touchscreen interface with graphical display

• Real-time monitoring of all parameters

• Pressure, temperature, run hours, fault history

• Multi-compressor sequencing capability

• Remote monitoring via Ethernet, Modbus, Profibus

• Data logging for maintenance optimization

• Predictive maintenance alerts

Why Choose Our Lubricated Rotary Screw Compressors?

• Proven Technology: Millions of installations worldwide

• Application Expertise: We help match the right compressor to your needs

• Quality Construction: Built to industrial standards

• Energy Efficiency: Advanced designs minimize power consumption

• Comprehensive Support: Worldwide parts and service network

For reliable, efficient, cost-effective compressed air in general industrial applications, lubricated rotary screw compressors deliver the performance and value that industry demands.