Oil-bearing grade of compressed air of micro-oil air-cooled screw air compressor

The oil-bearing grade of compressed air of micro-oil air-cooled screw air compressor is usually Class 1 to Class 2 of ISO 8573-1 standard. Some high-end models can be optimized to approach Class 0 but need to rely on post-treatment equipment. The following is a specific analysis:

core criteria for 1. oil grades

the oil content level of compressed air is based on international standards. ISO 8573-1 the standard divides the oil content into the following levels (based on total oil content, unit: mg/m & sup3;):

• Class 0 oil content ≤ 0.001 mg/m & sup3;(not detected), suitable for industries that are extremely sensitive to oil pollution (such as food, medicine, electronics).
• Class 1: Oil content 0.01-0.1 mg/m & sup3;(10-100 ppm), suitable for scenes with certain tolerance to oil content.
• Class 2: Oil content 0.1-1 mg/m & sup3;(100-1000 ppm), suitable for general industrial use.
• Class 3 and above: The oil content is higher, and it is usually not used in oil-sensitive occasions.

2. oil grade range of micro-oil air-cooled screw air compressor

1. typical oil grade
   the micro-oil screw air compressor will inject lubricating oil into the screw cavity during the compression process, and filter the oil through post-processing equipment such as oil and gas separator. The oil content of its output compressed air is usually:
   • Class 1 (0.01-0.1 mg/m & sup3;): Most micro-oil models can meet this standard by optimizing the oil and gas separation system (such as high-precision oil and gas separation core) to meet the requirements of general machinery manufacturing, automobile maintenance and other scenarios that are not sensitive to oil.
   • Class 2 (0.1-1 mg/m & sup3;): Some basic models or improperly maintained equipment may be in this range, which is suitable for construction, mining and other working conditions with low requirements on air source cleanliness.
2. Possibility of approaching Class 0
   A few high-end micro-oil models can approach Class 0 through the following technical optimization:
   • multistage oil and gas separation triple purification processes such as cyclone separation, coalescence filtration and activated carbon adsorption are adopted to reduce the oil content to less than 0.5 ppm.
   • Intelligent oil quantity control: through the electronic metering pump precise adjustment of fuel injection, reduce oil residue.
   • Nanoscale Filtration: Use nano-coated filter elements to improve filtration efficiency.
     But note that: Even after optimization, the micro-oil model still needs to rely on post-processing equipment (such as precision filters) to stably reach Class 0, and the filter element needs to be replaced regularly to maintain performance.

3. Key Factors Affecting Oil Grade

1. oil and gas separation efficiency
   the design of the oil-gas separator (such as the structure of the separation tank and the material of the filter element) directly affects the oil removal effect. Insufficient separation efficiency will cause the oil to exceed the standard.

2. Maintenance cycle
   the filter element, oil core and other consumables need to be replaced regularly (usually every 2000-3000 hours). If the filter element fails, the oil content may suddenly rise to more than 100 ppm.

3. Operating condition

   • pressure and flow: Operating pressure lower than the rated value or excessive flow fluctuation may reduce the separation effect.
   • Temperature control: Too low oil temperature will cause moisture condensation, dilute the lubricating oil and affect the separation performance.

4. quality of lubricating oil
   the use of inferior lubricating oil or oil deterioration will aggravate the problem of oil residue.

4. industry application recommendations

1. oil-sensitive industries (e. g. food, pharmaceuticals, electronics)
   priority selection oil-free screw air compressor(such as dry oil-free or water-lubricated oil-free models), the output air can directly reach Class 0 to avoid post-processing risks.

2. General industrial scenarios (e. g., machine building, auto repair, construction)
   micro-oil air-cooled screw air compressor is a cost-effective choice, but to ensure that:

   • configuration of efficient oil and gas separation system (such as two-stage buffer three-stage reflux design);
   • regularly replace the filter element and monitor the oil content;
   • select the appropriate pressure and flow parameters according to the working conditions.

3. Optimization for high-demand scenarios
   if the micro-oil model needs to approach Class 0, the following measures can be taken:

   • add post precision filter (such as activated carbon filter);
   • stable operation parameters using variable frequency drive technology;
   • with the heat recovery device to improve energy efficiency, indirectly reduce the risk of oil pollution.