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Oil-free Air Compressor

Oil-Free Air Compressors

The ZIQI OFW Series (Water-Lubricated) is the ultimate solution for industries demanding 100% Class 0 purity, such as pharmaceuticals, food & beverage, and electronics. Unlike traditional "dry screw" compressors that rely on fragile coatings and high temperatures, the OFW Series uses pure water for sealing and cooling. This achieves near-isothermal compression (<45°C), delivering 15% higher air volume and significantly lower maintenance costs than dry-type competitors.
Working Power
7.5 - 250 kW
Free Air Delivery
6.6 - 58.5 m³/min
Working Pressure
0.7 - 1.0 MPa (7 - 10 bar)
Transmission
Flexible Direct Drive
Cooling Method
Air-Cooling & Water-Cooling
Oil-free Air Compressor
Oil-free Air Compressor
Oil-free Air Compressor
Oil-free Air Compressor
Oil-free Air Compressor
Oil-free Air Compressor
Oil-free Air Compressor
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An oil-free air compressor is designed to deliver 100 oil free air with reliable air purity, meeting ISO 8573-1 Class 0 and other strict ISO class requirements. These oil free compressors provide high quality oil free compressed air for food and beverage processing and other industries where contamination must be avoided. Compared with traditional systems, free air compressors help reduce operating cost while maintaining consistent performance across a wide range of applications. As a dependable air compressor solution, oil-free designs support stable production, clean processes, and long-term efficiency.
Product Details Product Applications


💧 100% Oil-Free · Class 0 Certified

ZIQI OFW Water-Lubricated Oil-Free Compressor

Stainless Steel Air End · Near-Isothermal Compression · ISO 8573-1 Class 0 · 17 Models from 7.5–250 kW
Class 0
ISO 8573-1 Certified
Zero Oil Risk
<50°C
Compression Temp
Near-Isothermal
17
Models Available
7.5 – 250 kW
15%
More Air per kW
vs Dry Oil-Free

Why ZIQI Water-Lubricated Technology Is the Future of Oil-Free Air

Unlike traditional dry oil-free compressors that rely on extreme operating temperatures (up to 200°C) and Teflon-coated rotors that degrade over time, the ZIQI OFW Series utilizes pure water for sealing, cooling, and lubrication. This method guarantees ISO 8573-1 Class 0 air quality while the injected water acts as a natural scrubber — washing dust and impurities from the intake air during compression.

With no Teflon coating to peel off, no high-temperature wear, no oil filters, and no oil separators to change, the ZIQI OFW offers unparalleled durability and the lowest Total Cost of Ownership (TCO) for industries demanding absolute air purity. The stainless steel 304/316 compression chamber with polymer composite star wheel ensures zero corrosion risk throughout the machine's entire lifespan. With 17 models spanning 7.5 to 250 kW — from compact air-cooled units for small cleanrooms to large water-cooled systems for full-scale pharmaceutical plants — the OFW series covers every Class 0 application. For dry-type oil-free options, see our OFD dry screw series.

Core Hardware — Engineered for Absolute Purity
Advanced metallurgy and thermodynamics combined in the ultimate oil-free air end.
Corrosion Proof🛡️

Stainless Steel Air End

The entire compression chamber — rotor, housing, and internal passages — is crafted from high-grade Stainless Steel (304/316) or specialized copper alloy equivalents. Zero rust, zero contamination, zero compromise.

  • Material: Full SS housing + polymer composite star wheel

  • Structure: Single-screw design — balanced radial forces, low vibration

  • Purity: Output air is absolutely clean and rust-free

  • Life: No coating degradation — constant efficiency over decades

High Efficiency💧

Near-Isothermal Compression

Water's heat capacity is vastly superior to oil or air. Injecting pure water during compression absorbs heat instantly, achieving thermodynamically ideal near-isothermal compression — the most energy-efficient process possible.

  • Efficiency: ~15% more air per kW than dry screw types

  • Temperature: Operating temp safely below 50°C (vs 200°C+ dry)

  • Scrubbing: Water washes dust from intake air during compression

  • Eco-Friendly: Zero waste oil disposal — only clean water discharge

✅

100% Oil-Free Certified

Tested and certified to ISO 8573-1 Class 0. There is physically no lubricating oil anywhere inside the compressor — completely eliminating the risk of oil carry-over into your product or process.

🌬️

"Washed" Clean Air

The injected water acts as a natural air scrubber, dissolving airborne dust and impurities during compression. The result is exceptionally clean discharge air — cleaner than what dry oil-free compressors can achieve alone.

📉

Ultra-Low Maintenance

No oil changes, no oil filters, no oil separators to replace. Maintenance is simplified to water filter changes and bearing lubrication — cutting annual service costs by 40-60% versus dry oil-free machines.

Industries That Demand Class 0 Air
Any trace of oil contamination is unacceptable in these applications.
🍞Food & BeverageDirect food contact, packaging, bottling, fermentation
💊PharmaceuticalTablet coating, conveying, cleanroom supply, GMP lines
🔬Electronics & SemiconductorCleanroom air, wafer handling, PCB manufacturing
🏥Medical & DentalSurgical air, breathing systems, dental chairs, lab air

Tell us your industry, flow rate, and air quality requirements — we'll spec the right OFW model.

Get Class 0 Quotation            WhatsApp Us
Dry Oil-Free vs ZIQI OFW Water-Lubricated
Why modern critical industries are switching to water-lubricated systems.
Feature Traditional Dry Oil-Free ZIQI OFW (Water-Lubricated)
Compression Temperature Extremely high (>200°C) Ultra-low (<50°C) — near-isothermal
Air End Material Teflon-coated rotors — coating degrades over time Stainless steel 304/316 — no coating, constant efficiency
Discharge Air Quality Class 0 — but no dust washing Class 0 + natural water-scrubbed "washed" air effect
Energy Efficiency Lower — high temp compression wastes energy ~15% more air per kW due to isothermal process
Air End Overhaul Every 3-5 years — $8,000-$15,000 per overhaul Not required — SS construction lasts machine lifetime
Consumables Oil filters + oil separators + air end coating repair Water filter only — no oil, no coating, no separators
Annual Maintenance Cost $3,000-$6,000 typical $1,000-$2,000 — 40-60% lower
Environmental Impact Requires Teflon coating disposal Zero waste oil — only clean water discharge
10-Year TCO
(55 kW model)		 $80,000-$120,000 (incl. 2-3 overhauls) $50,000-$70,000 — up to 40% lower lifetime cost
How to Select an Oil-Free Compressor
Three steps to the right Class 0 solution for your facility.
1

Verify Air Quality Requirements

Confirm that your facility strictly requires ISO 8573-1 Class 0 compressed air (zero risk of oil contamination). This is mandatory for direct food contact, electronics cleanrooms, and medical/dental use.

2

Calculate Air Demand (m³/min)

Determine the maximum volumetric flow rate needed by your pneumatic processes. The OFW series ranges from 0.75 m³/min (7.5 kW) up to 42.0 m³/min (250 kW). Add 15-20% margin for future expansion.

3

Select Discharge Pressure & Cooling

Choose from 0.7, 0.8, or 1.0 MPa. Models 55 kW and above offer both air-cooled (A) and water-cooled (W) options. Not sure which fits? Contact our engineers for a free sizing recommendation.

Full Technical Specifications
17 models from 7.5 to 250 kW. "A" = Air-Cooled, "A/W" = Air or Water-Cooled, "W" = Water-Cooled only. Requires purified water supply (RO/Deionized).

OFW Compact Series — 7.5 to 45 kW

Air-Cooled · Single Screw · Class 0
Model Motor Power Air Delivery (m³/min) @ Pressure Noise dB(A) Dimension L×W×H (mm) Weight (kg) Outlet
kW HP 0.7 MPa 0.8 MPa 1.0 MPa
OFW-7.5A 7.5 10 0.90 0.85 0.75 58±2 1060×760×1020 500 G3/4"
OFW-11A 11 15 — — 1.00 58±2 1300×870×1200 600 G3/4"
OFW-15A 15 20 1.85 1.70 — 60±2 1300×870×1200 650 G3/4"
OFW-18.5A 18.5 25 2.60 2.20 1.80 61±2 1420×1020×1350 700 G1"
OFW-22A 22 30 3.40 3.30 2.60 61±2 1420×1020×1350 750 G1"
OFW-30A 30 40 5.20 5.00 3.20 64±2 1670×1250×1450 1150 G1-1/4"
OFW-37A 37 50 6.40 6.30 5.00 64±2 1680×1200×1500 1200 G1-1/4"
OFW-45A 45 60 7.80 7.70 6.20 66±2 2045×1320×1600 1400 G2"

OFW Industrial Series — 55 to 250 kW

Air / Water-Cooled · Single Screw · Class 0
Model Motor Power Air Delivery (m³/min) @ Pressure Noise dB(A) Dimension L×W×H (mm) Weight (kg) Outlet
kW HP 0.7 MPa 0.8 MPa 1.0 MPa
OFW-55A 55 75 10.0 9.0 7.8 66±2 2045×1320×1660 1600 G2"
OFW-75A 75 100 13.5 13.4 10.0 70±2 2300×1470×1800 1780 G2"
OFW-90A/W 90 120 16.5 14.0 13.0 70±2 3000×1850×1920 (A)
2250×1700×1800 (W)		 2500 G2½"
OFW-110A/W 110 150 20.3 20.0 16.5 72±2 3000×1850×1920 (A)
2250×1700×1800 (W)		 3100 G2½"
OFW-132A/W 132 180 23.1 23.0 20.0 72±2 3000×1850×1920 (A)
2250×1700×1800 (W)		 3250 G2½"
OFW-160W 160 215 29.0 28.0 24.0 72±2 2750×1850×1920 4100 DN80
OFW-185W 185 250 30.0 29.5 28.0 74±2 2750×1850×1920 4300 DN80
OFW-200W 200 270 36.5 36.0 30.0 74±2 2780×1860×1950 4500 DN100
OFW-250W 250 340 42.0 41.0 38.0 74±2 2780×1860×1950 5000 DN100

* "A" = Air-Cooled, "A/W" = Air or Water-Cooled option, "W" = Water-Cooled only. "—" indicates pressure configuration not available for that model. All data verified against master spec sheet. Requires purified water supply (RO or deionized water). Specifications subject to change. Contact our engineers for exact configuration and pricing.

Need Class 0 Pure Air for Your Facility?

Tell us your industry, air demand, and quality requirements. Our engineers will recommend the optimal OFW model and deliver a technical proposal within 24 hours.

Request Technical ProposalWhatsApp: +86 150 2676 7628
Frequently Asked Questions
Is the ZIQI OFW compressor truly 100% oil-free?
Yes. The OFW series does not use any lubricating oil in the compression chamber. It relies entirely on pure water for lubrication, sealing, and cooling, guaranteeing ISO 8573-1 Class 0 oil-free air — completely safe for food, beverage, pharmaceutical, and electronics manufacturing.
Will the water cause the internal components to rust?
No. The entire compression chamber, including the single-screw rotor and housing, is manufactured from high-grade Stainless Steel (304/316) or specialized copper alloys. These materials are 100% corrosion-resistant and will not degrade over the machine's lifetime.
What is Near-Isothermal Compression?
Water has a heat capacity vastly superior to oil or air. As water is injected during compression, it absorbs heat instantly, keeping the operating temperature below 50°C — approaching an "isothermal" state. This is thermodynamically the most efficient compression process possible, requiring significantly less energy than the 200°C+ temperatures in dry oil-free compressors.
What kind of water is required for the compressor?
The compressor requires RO (Reverse Osmosis) water, demineralized water, or purified drinking-quality water. This prevents scale buildup and ensures the highest air purity. A basic RO water system is a low-cost addition and ZIQI can supply integrated water treatment units if needed.
What is the difference between water-lubricated and dry oil-free compressors?
Dry oil-free compressors use Teflon-coated rotors spinning at high speed without lubrication, generating extreme heat (200°C+). The coating degrades over time, requiring expensive air end overhauls every 3-5 years. Water-lubricated compressors inject pure water for sealing, cooling, and lubrication — achieving much lower temperatures (<50°C), ~15% better energy efficiency, and eliminating air end overhauls entirely. Both achieve Class 0 certification, but water-lubricated machines have significantly lower TCO.
How much energy does a water-lubricated compressor save compared to dry type?
The OFW series delivers approximately 15% more air per kilowatt compared to dry oil-free compressors — because near-isothermal compression wastes far less energy as heat. For a typical 55 kW compressor running 8,000 hours per year, this translates to roughly $4,000-$6,000 in annual electricity savings.
What industries require Class 0 oil-free compressed air?
Any industry where oil contamination is unacceptable: food and beverage processing (direct food contact, packaging, bottling), pharmaceutical manufacturing (GMP tablet coating, cleanrooms), electronics and semiconductor fabrication (wafer handling, PCB assembly), medical and dental applications (surgical air, breathing systems), and specialty chemical processing. For more details, see our full oil-free compressor range.
What maintenance does a water-lubricated compressor need?
Maintenance is drastically simplified versus both oil-injected and dry oil-free compressors. There are no oil changes, no oil filters, and no oil separators. Routine service includes water filter replacement, water quality monitoring, and standard bearing lubrication — reducing annual maintenance costs by 40-60% compared to dry oil-free machines and eliminating the $8,000-$15,000 air end overhauls entirely.
Related Products
🔵OFD Dry Oil-Free ScrewDry-type Class 0 for high-temp tolerance⚙️GAS Screw CompressorOil-injected 7.5–180 kW industrial air💧Air Treatment EquipmentDryers, filters, tanks for pure air systems📞Contact ZIQIFree Class 0 system design support

* All 17 OFW models verified against master spec sheet. "A" = Air-Cooled, "A/W" = Air or Water-Cooled, "W" = Water-Cooled only. Requires purified water supply (RO or deionized). Specifications subject to change. Contact ZIQI for exact configuration and pricing.

ZIQI OFW Series Water Lubricated Compressor Specifications

Complete Technical Specifications

OFW Series Water Lubricated Oil-Free Compressor (7.5kW - 250kW)

Model Motor Power Air Delivery (m³/min) @ Pressure Noise
dB(A)		 Dimension (mm) Weight
(kg)		 Outlet
kW HP 0.7 MPa 0.8 MPa 1.0 MPa L W H
OFW-7.5A 7.5 10 0.90 0.85 0.75 58±2 1060 760 1020 500 -
OFW-11A 11 15 - - 1.0 58±2 1300 870 1200 600 G3/4"
OFW-15A 15 20 1.85 1.70 - 60±2 1300 870 1200 650 G3/4"
OFW-18.5A 18.5 25 2.60 2.20 1.80 61±2 1420 1020 1350 700 G1"
OFW-22A 22 30 3.40 3.30 2.60 61±2 1420 1020 1350 750 G1"
OFW-30A 30 40 5.20 5.00 3.20 64±2 1670 1250 1450 1150 G1-1/4"
OFW-37A 37 50 6.40 6.30 5.00 64±2 1680 1200 1500 1200 G1-1/4"
OFW-45A 45 60 7.80 7.70 6.20 66±2 2045 1320 1600 1400 G2"
OFW-55A 55 75 10.0 9.0 7.8 66±2 2045 1320 1660 1600 G2"
OFW-75A 75 100 13.5 13.4 10.0 70±2 2300 1470 1800 1780 G2"
OFW-90A 90 120 16.5 14.0 13.0 70±2 3000 1850 1920 2500 G2-1/2"
OFW-110W 110 150 20.3 20.0 16.5 72±2 3000 1850 1920 3100 G2-1/2"
OFW-132W 132 180 23.1 23.0 20.0 72±2 3000 1850 1920 3250 G2-1/2"
OFW-160W 160 215 29.0 28.0 24.0 72±2 2750 1850 1920 4100 DN80
OFW-185W 185 250 30.0 29.5 28.0 74±2 2750 1850 1920 4300 DN80
OFW-200W 200 270 36.5 36.0 30.0 74±2 2780 1860 1950 4500 DN100
OFW-250W 250 340 42.0 41.0 38.0 74±2 2780 1860 1950 5000 DN100

Cooling Method: "A" = Air-cooling, "W" = Water-cooling. (Models 90kW+ available in both, 160kW+ standard water cooled).

Starting Method: Direct Start (7.5-11kW), Y-▲ Starter (15kW+), or Frequency Start (VFC) available for all models.

Water Requirement: Requires purified water supply (RO water or distilled water) to prevent scaling.

Note: 60Hz power supply requires customized Variable Frequency Drive (VSD).

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