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:funk: special term for air compressor, air compressor, whole process air compressor； A machine designed based on the working principle that the rotation of twin screws (also called yin and yang rotors) changes the volume of gas. It can suck in natural air and then complete the work through several internal processes, and finally discharge the compressed air that meets the pressure requirements. This machine is called a screw air compressor. There are many forms of expression for the working pressure of air compressors. Here we mainly introduce the commonly used pressure expression units for screw air compressors. ； ① Working pressure, domestic users often call it exhaust pressure. Working pressure refers to the highest pressure of gas discharged by the air compressor ； ② Commonly used units for working pressure are: bar or Mpa, 1 bar = 0.1 Mpa ； ③ Generally, users usually call the pressure unit: Kg (kilogram), 1 bar = 1 Kg. Volume flow rate of air compressor ① Volume flow rate, domestic users often call it exhaust volume. Volumetric flow refers to the volume of gas discharged by the air compressor per unit time under the required exhaust pressure, converted to the amount of air intake. ② The volumetric flow unit is: m3/min (cubic/minute) or L/min (liter/minute), 1m3 (cubic) = 1000L (liter) ； ③ Generally, the commonly used flow unit is: m3/min (cubic meter/minute) ； ④ Volume flow is also called exhaust volume or nameplate flow in my country. Power of air compressor ① Generally speaking, the power of air compressor refers to the nameplate power of the matching drive motor or diesel engine. ； ② The unit of power is: KW (kilowatt) or HP (horsepower), 1KW ≈ 1.333HP. A.Volume flow: Volume flow is also called exhaust volume or nameplate flow in my country. Generally speaking, under the required exhaust pressure, the volume of gas discharged by the air compressor per unit time is converted to the intake state, that is, the volume value at the suction pressure at the first-stage air inlet pipe and the suction temperature and humidity. The unit is m3/min. B. Exhaust pressure: The pressure referred to in the compressor industry is what we called pressure in middle school. The pressure measured with atmospheric pressure as the zero point is called gauge pressure. The pressure with absolute vacuum as the zero point is called absolute pressure. The discharge pressure usually given on the compressor nameplate is gauge pressure. The unit is MPa or bar. C. Gas oil content: The mass of oil (including oil droplets, suspended particles, and oil vapor) contained in a unit volume of compressed air, converted to the value under standard atmospheric conditions of an absolute pressure of 0.1MPa, a temperature of 20°C, and a relative humidity of 65%, in mg/m3. D.PPM: A symbol indicating the content of trace substances in a mixture, referred to as parts per million or parts per million (parts by weight PPMw and volume ratio PPMv). Usually what we call PPM is the weight ratio. (One millionth of 1kg is milligram) 1PPMw=1.2mg/m3 (PA=0.1MPa, t=20℃, φ=65%) E. Dew point temperature Humid air is cooled under constant pressure, so that the unsaturated water vapor originally contained in the air becomes saturated water vapor. In other words, when the temperature of the air drops to the dew point, the original unsaturated water vapor contained in the air reaches a saturated state (that is, the water vapor begins to liquefy and liquid condenses out). Similarities and differences between compressor volumetric flow and pneumatic component air consumption. Compressor volumetric flow refers to the flow of free air, while pneumatic component air consumption refers to the flow of air in a compressed state. Its conversion formula: Qself=Qpressure * ε m3/min ε=P row (absolute pressure)/P suction (absolute pressure) = (P row (gauge pressure) + 1.033)/1.033 = (P' row (gauge pressure) + 0.1013)/0.1013 Among them, P row (gauge pressure) - unit kg/cm2 P' row (gauge pressure) - unit MPa