What is the purity of compressed air in an ordinary factory
The compressed air purity standards of ordinary factories usually follow the international standard ISO 8573-1, and the specific levels vary according to industry and application needs. The following is a detailed analysis:
1. Purity standard for compressed air in ordinary factories
The main basis for the purity of compressed air in ordinary factoriesISO 8573-1 standardThis standard detects the amount of water in compressed airParticulate matter, water vapor and oil contentClassification of three major pollutants:
| level | Particulate matter (μm) | Pressure dew point (℃) | Oil content (mg/m³) | typical application scenarios |
|---|---|---|---|---|
| Class 1 | ≤0.1 (maximum concentration) | ≤-70 | ≤0.01 | Precision electronics, semiconductors |
| Class 3 | ≤1 (maximum concentration) | ≤-20 | ≤1 | General industries (e.g. machinery, textiles) |
| Class 4 | ≤5 (maximum concentration) | ≤3 | ≤5 | Food packaging, low-pressure equipment |
Common grade in general factories：
- general industrial: Class 3 (such as machining workshops, small assembly lines)
- Food/Drug Packaging: Class 4 (requires dehumidification device)
- pneumatic tools: Class 5 (oil content ≤10mg/m³)
2. The impact of compressed air purity on production
- Excessive particulate matter：
- equipment wear: Accelerate the aging of seals on pneumatic tools, cylinders and other equipment.
- product contamination: For example, the spraying industry may cause paint defects.
- Water vapor exceeds the standard：
- equipment corrosion: Metal pipes and joints are rusty, increasing the risk of air leakage.
- process disturbances: For example, moisture in plastic blow molding causes bubble defects.
- Oil content exceeds standard：
- product contamination: Oil may adhere to product surfaces (such as auto parts).
- equipment failure: Sludge clogging precision instruments (such as sensors).
actual case: Due to the excessive oil content in the compressed air (5mg/m³) in an automobile parts factory, the adhesion of the brake pad coating decreased, and the batch defective rate increased by 3.2%.
3. Quality control measures for compressed air in ordinary factories
- primary purging：
- Air compressor selection: Oil-free lubricated screw machines are preferred (reduce oil content from the source).
- primary filter: Install cyclone separator + pre-filter to remove large particulate impurities (efficiency>90%).
- deep drying：
- Leng gan machine: Reduce the temperature to 2-10℃, and the pressure dew point reaches 3-10℃ (applicable to Class 4).
- dryer: Deeply dehumidify with an adsorbent (such as alumina), with a pressure dew point ≤-40℃ (applicable to Class 3).
- precision filtration：
- Activated Carbon Filter: Absorb oil vapor (outlet oil content <0.01mg/m³).
- Ultra-precision filter: Intercept 0.01μm particles (used in Class 1 scenarios).
- monitoring and maintenance：
- regular testing: Use an infrared spectrophotometer to detect oil content, and a dew point meter to monitor humidity.
- equipment maintenance: Replace filter elements quarterly and check dryer adsorbent annually.
4. Cost control suggestions
- equipment investment: The basic three-level purification system (compressor + cold dryer + filter) is about 50,000 – 80,000 yuan, suitable for small and micro factories.
- energy consumption optimization: Using variable frequency air compressor, energy consumption is reduced by 15%-20%.
- equipment selection: Match the equipment according to the gas consumption to avoid energy waste caused by “big horses and small cars”.
conclusion: Ordinary factories should select compressed air levels according to specific process requirements, and ensure stable air quality through regular inspections (recommended once a month) and equipment maintenance (quarterly). For high value-added products (such as medical devices), it is recommended to upgrade to Class 2 or higher standards.