How to distinguish micro-oil from oil-free air compressor

There are significant differences between micro-oil and oil-free air compressors in terms of lubrication, compressed air quality, application scenarios, maintenance costs and equipment structure, which can be distinguished by the following methods:

1. lubrication: the core difference

1. micro-oil air compressor
   • lubrication principle: By injecting a small amount of lubricating oil (usually synthetic oil or mineral oil) into the screw cavity, the following functions are achieved:
     • cooling: Absorbs the heat generated during compression and reduces the exhaust temperature.
     • Seal: oil film is formed between the screw rotors to prevent gas leakage.
     • Lubrication: Reduce the friction between the rotor and the bearing and extend the life of the equipment.
   • Oil residue: Compressed air will carry trace oil (usually 0.01-1 mg/m & sup3;), which needs to be further purified by post-processing equipment such as oil and gas separators and precision filters.
2. Oil-free air compressor
   • lubrication principle: No lubricating oil is used at all, and oil lubrication is replaced by the following technology:
     • dry oil-free: Using special ceramic or carbon steel rotor, the surface is precision machined to reduce friction.
     • water lubricated oil free: Water is used as the lubricating medium to achieve cooling, sealing and lubrication through water film.
   • Oil residue: Compressed air does not contain oil and can directly reach Class 0 of ISO 8573-1 standard (oil content ≤ 0.001 mg/m & sup3;).

2. compressed air quality: direct judgment basis

1. micro-oil air compressor
   • oil content: Even after high-efficiency oil and gas separation, traces of oil (Class 1-2) may still remain in the compressed air.
   • Applicable Scenarios: General industrial scenarios that are not sensitive to oil content, such as machinery manufacturing, auto repair, construction, etc.
   • Post-processing requirements A precision filter (such as an activated carbon filter) is required to further reduce the oil content, but it cannot be completely eliminated.
2. Oil-free air compressor
   • oil content: Compressed air is completely oil-free, which can directly meet the requirements of high cleanliness (Class 0).
   • Applicable Scenarios: Industries that are extremely sensitive to oil, such as food, medicine, electronics, semiconductor manufacturing, etc.
   • Post-processing requirements: No additional oil removal equipment is required, but dryers, dust collectors, etc. may be required to control moisture and particulate matter.

3. application scenarios: industry demand-oriented

1. micro-oil air compressor
   • advantage: Low cost, simple maintenance, high energy efficiency (oil lubrication reduces friction loss).
   • Typical applications:
     • auto repair shop (painting, pneumatic tools).
     • Construction site (concrete spraying, pneumatic nail gun).
     • General machinery manufacturing (pneumatic control, power source).
2. Oil-free air compressor
   • advantage: Compressed air has no oil pollution to avoid product defects or safety risks.
   • Typical applications:
     • food Industry beverage filling and packaging line (to prevent oil contamination of food).
     • Pharmaceutical industry pharmaceutical production, sterile environment (in line with GMP standards).
     • Electronic industry: Chip manufacturing, circuit board cleaning (to avoid short circuit caused by oil).
     • Textile Industry: Pneumatic loom (to prevent oil pollution cloth).

4. maintenance costs and complexity

1. micro-oil air compressor
   • maintenance content: Regularly replace the lubricating oil, oil and gas separation core, air filter element, oil filter element, etc.
   • Cost: Consumables are replaced more frequently (usually every 2000-3000 hours), but the single cost is lower.
   • Risk: If the maintenance is improper (such as filter element failure), the oil content may exceed the standard, and the post-processing cost shall be increased.
2. Oil-free air compressor
   • maintenance content:
     • dry oil-free: Regularly check the rotor for wear, replace the bearing, and clean the cooler.
     • water lubricated oil free regularly replace the water quality stabilizer, clean the waterway and check the water pump.
   • Cost: The initial investment is higher (the rotor material is special), but the long-term operating cost may be lower (no oil pollution treatment cost).
   • Risk: After the dry rotor is worn, the whole machine or rotor needs to be replaced, and the maintenance cost is high; water lubrication needs to strictly control the water quality, otherwise it is easy to scale.

5. equipment structure and volume

1. micro-oil air compressor
   • structure: Contains oil and gas separation tank, oil cooler, oil filter and other components, with large volume.
   • Noise: High operating noise (friction is reduced due to oil lubrication, but noise may be generated during oil and gas separation).
2. Oil-free air compressor
   • structure:
     • dry oil-free: The structure is compact, but the rotor processing accuracy is extremely high.
     • water lubricated oil free: Water tank, water pump and other waterway systems are required, and the volume may be slightly larger.
   • Noise the dry type has low noise (no oil and gas separation process), and the noise of the water lubricated type depends on the performance of the water pump.

Summary of 6. differentiation methods

7. purchase recommendations

1. if not sensitive to oil: Choose micro-oil air compressor, which is more cost-effective and simple to maintain.
2. If high cleanliness air is required choose an oil-free air compressor to avoid oil pollution to the product or the environment.
3. If the budget is limited but need close to oil-free effect micro-oil type precision filter can be selected, but the oil content needs to be monitored regularly.
4. If the ambient humidity is high: Water-lubricated oil-free air compressor is preferred to avoid the combination of oil and moisture to form emulsion.