. Common Terms of Air Compressors
• Pressure
The discharge pressure specified on the compressor nameplate is usually gauge pressure, not absolute pressure.
Common pressure units: bar, MPa. In the air compressor industry, "kilogram" refers to "bar", i.e., 1 kilogram equals 1 bar. Conversion: 1 MPa (megapascal) = 1000 kPa (kilopascal), 1 bar = 0.1 MPa.
• Volumetric Flow Rate
Domestically, it is also called displacement or nameplate flow rate. It refers to the volume of gas discharged by the air compressor per unit time, converted to the intake state (i.e., the volume of suction air). According to national standards, the actual displacement of an air compressor is qualified if it is within ±5% of the nominal flow rate. Common units: m³/min, L/s.
• Oil Content in Gas
The mass of oil (including oil droplets, suspended particles, and oil vapor) contained in a unit volume of compressed air. The commonly mentioned "PPM" in the industry is a weight ratio unit: 1 PPM means one part per million by weight, i.e., 1 milligram in 1 kilogram.
• Pressure Dew Point
It refers to the temperature at which unsaturated water vapor in a gas under a certain pressure condenses into saturated water vapor and precipitates when the gas is cooled to that temperature. Atmospheric dew point is the temperature at which unsaturated water vapor in gas condenses into saturated water vapor and precipitates under standard atmospheric pressure. In the air compressor industry, dew point indicates the dryness of the gas.
• Specific Power
It refers to the power consumed by the compressor per unit volumetric flow rate. It is an important indicator for evaluating the energy efficiency of compressors. Unit of air compressor specific power: KW/m³.
Air compressor energy efficiency levels are divided into 4 grades:
Grade 1 (optimal level): Reaching international advanced level, most energy-efficient with the lowest energy consumption.
Grade 2: Relatively energy-efficient.
Grade T (target energy efficiency limit value): Its energy efficiency is better than Grade 3, and it has replaced Grade 3 energy efficiency value since December 1, 2013.
Grade 3 (energy efficiency limit value): High energy consumption, serving as the market access indicator.
Production and sales of products below Grade 3 are prohibited.
