Pure Water. Pure Air. The Most Cost-Effective Class 0 Solution.
The ZIQI OFW Series replaces oil with pure water in the compression chamber. Water acts as the sealant, lubricant, and coolant.
Because water has a high specific heat capacity, the compression temperature is kept below 50°C (near isothermal). This not only guarantees ISO Class 0 100% Oil-Free air but also improves volumetric efficiency by 15% compared to dry compression.
ISO Class 0
Zero risk of contamination. Unlike oil-injected compressors with filters, the OFW series uses no oil in the entire compression system.

To handle water injection, the entire host (housing and rotors) is made of advanced corrosion-resistant materials.
Pure water is injected directly into the compression chamber. It seals the gap between the rotor and housing (improving efficiency) and absorbs the heat of compression immediately.
Water Lubricated (OFW) vs. Dry Oil-Free Screw
| Feature | Dry Oil-Free Screw | ZIQI OFW Water Lubricated |
|---|---|---|
| Compression Temp | High (~180°C - 200°C) | Low (< 50°C Isothermal) |
| Efficiency | Standard | +15% Higher Efficiency |
| Material | Coated Carbon Steel (Coating may peel) | Solid Stainless Steel (No peeling) |
| Maintenance Cost | High (Expensive Air End Rebuild) | Low (Simple Water Change) |
OFW Series (7.5kW - 160kW)
| Model | Motor Power | Air Delivery (m3/min) | Cooling | Noise dB(A) | Weight (kg) | Outlet | |||
|---|---|---|---|---|---|---|---|---|---|
| kW | HP | 0.7 MPa | 0.8 MPa | 1.0 MPa | |||||
| OFW-15A | 15 | 20 | 2.35 | 2.25 | 2.00 | Air/Water | 62 | 450 | G1" |
| OFW-22A | 22 | 30 | 3.60 | 3.50 | 3.10 | Air/Water | 64 | 500 | G1" |
| OFW-37A | 37 | 50 | 6.10 | 5.80 | 5.20 | Air/Water | 66 | 850 | G1?" |
| OFW-55A | 55 | 75 | 9.00 | 8.70 | 7.60 | Air/Water | 68 | 1200 | DN50 |
| OFW-75A | 75 | 100 | 12.5 | 12.0 | 10.5 | Air/Water | 70 | 1500 | DN65 |
| OFW-90A | 90 | 120 | 15.2 | 14.8 | 12.8 | Air/Water | 72 | 1900 | DN65 |
| OFW-132A | 132 | 180 | 23.0 | 22.5 | 20.0 | Water | 75 | 2800 | DN80 |
| OFW-160A | 160 | 215 | 27.5 | 26.5 | 24.0 | Water | 78 | 3200 | DN100 |
* Note: OFW series uses automatic water replenishment system. Requires clean tap water or RO water source.
Does the water cause rust inside the compressor?
No. ZIQI OFW series uses 304/316 stainless steel or special polymer materials for all components in contact with water (rotors, housing, piping), ensuring absolute corrosion resistance.
How often do I need to change the water?
The system has an automatic water exchange and filtration function. Generally, a manual check is recommended every 200 hours, but the intelligent controller manages the daily replenishment automatically.