Single Stage Variable Speed Water Injected Oil-Free Screw Compressor Model: OGWY(B)
- Discharge Pressure: 7-10 [bar], 101-145 [psig]
- Free Air Delivery: 0.9-43 [m³/min], 32-1519 [cfm]
- Rated Motor Power: 7.5-250 [kW], 10-340 [hp]
- Features
- Technical Specifications
- Configuration
- Downloads
100% Oil-Free Operation
The compressor uses water for lubrication instead of oil, ensuring 100% clean and pure compressed air that meets ISO 8573-1 (2010) and TÜV CLASS ZERO standards.
High Efficiency
- Single-Screw Technology: Eliminates clearance volume, improving performance.
- Water Lubrication: Seals gaps in the compression chamber, allowing for high efficiency even at temperatures close to 50°C.
- Near Isothermal Compression: Uses water as a cooling medium to maintain constant air temperature throughout compression, reducing energy consumption.
Low Noise
- Quiet Design: Single screw airend utilizes a stainless steel screw rotor and polymer-made star wheels for meshing components.
- Direct Coupling: Features a direct coupling between the motor and the screw, minimizing vibration and noise.
- Sound Insulation: The enclosure is lined with sound-absorbing material to effectively reduce noise levels.
Energy Saving
- VSD+PM Motor: Variable speed drive combined with a permanent magnet motor for exceptional energy efficiency and savings.
Stable Air Delivery
- Dynamic Pressure Control: The controller continuously monitors discharge pressure using the compressor’s pressure sensor and adjusts the inverter’s output frequency to regulate motor speed and ensure stable free air delivery.
Robust Components
- Stainless Steel 304: All piping and key components, including the airend (rotor and housing) that come into contact with air and water, are constructed from durable Stainless Steel 304. This ensures long-lasting performance and resistance to corrosion.
OGWY(B) Model Configuration
Gairs Airend
- Stainless steel 304 rotor & housing
- Star wheel pieces material: PEEK (polyether ether ketone)
- Speed of Revolution: 3000 rpm
Permanent Magnet Motor
- Motor Enclosure Protection: IP55
- Energy Efficiency Class: IE5
- Direct coupling
Inverter & PLC controller
- Brand: Inovance
- Language: Chinese, English, Korean, Russian
Centrifugal Fan (air-cooled unit)
- Enhanced cooling efficiency
- Reduced noise levels
Electrics
- AC Contactor brand: Schneider
Parts & Valves
- Water softener brand: Pentair
- Normally open/closed solenoid valves: SMC

In-House Designed and Manufactured Airend
Since 1988, all of Gairs’ airends have been produced in-house. For a single screw airend, the screw rotor is crafted from stainless steel to enhance wear and corrosion resistance, while the star wheel components are made from polyether ether ketone (PEEK)—a high-performance polymer known for its superior mechanical and chemical resistance, even at elevated temperatures.
Low Maintenance Cost
For regular maintenance, just swap out the air filter element, water filter element, and water softener element. No need to worry about a bunch of extra spare parts like with other compressors.


Save Big on Your Energy Costs!
With a motor power of 90kW at 7 bar, the OGWY(B) delivers 16.8m³/min, outperforming a comparable dry twin screw compressor at 15.4m³/min. This efficiency translates to a difference of approximately 10kW/h in electricity usage.
Annual Savings Calculation:
Electricity Cost: $0.15 per kW/h
Energy Savings: 10kW/h×24hours×365days×$0.15=$13,140
By switching to the OGWY(B) models, you could save around $13,140 annually on your electric bill!
Comparison
Water-lubricated Oil-free Single Screw Compressor |
Dry Oil-free Twin Screw Compressor |
|
Air Quality | 100% oil free due to water lubrication |
Potential oil contamination due to oil in the gear box |
Discharge Temp. | Up to 55℃ | 180-200℃ |
Cooling Method | No internal cooling system | Requires interstage and after-cooling systems |
Airend Structure | High efficiency, no clearance volume | Lower efficiency, has clearance volume |
Rotational Speed | 3000 r/min | 18000 r/min |
Regular Maintenance | Air filter, water filter, and water softener resin elements only | Air, oil filter elements, seal kits, o-rings, separator element, etc. |


Frequently Asked Questions
The following are frequently asked by our customers about OGWY(B) oil-free water lubricated air compressors.
Reverse osmosis (RO) water must be used as the lubricating water source.
In our Gairs OGW series of water-lubricated compressors, lubricating water is injected into the airend to facilitate cooling. Inside the airend, the water acts as a seal between the star wheel and the screw rotor, enhancing the compressor’s volumetric efficiency. Since the lubricating water continuously circulates within the system, its quality directly impacts the airend’s lifespan.
1. Reduced Maintenance: Water-injected oil free compressors generally have fewer moving parts and less wear, leading to lower maintenance needs.
2. Lower Operating Temperature: They operate at cooler temperatures, reducing the risk of overheating and extending equipment life.
3. Better Efficiency: Water injection helps with cooling and sealing, improving efficiency and energy consumption.
4. Cleaner Air Supply: They produce 100% oil-free compressed air, reducing contamination risks.
5. Quieter Operation: Typically quieter than dry twin screw compressors due to the single screw airend structure.
We suggest replacing the air filter element every 2000 hours of operation, the water filter element every 1000 hours, and the water softener element twice a year.
Maintenance of the airend depends on the compressor’s usage frequency and the working conditions of the compressor room. For single-stage models like OGWY(B) and OGWBD, it is recommended to perform maintenance every 3 to 5 years. For specific inquiries, please contact us directly.
Typically, the lead time for a single-stage model is approximately 25-30 working days, while the lead time for a two-stage model is around 40-45 working days.