Air compressors are commonly used equipment in manufacturing companies, petrochemical mines, transportation and construction industries. Screw air compressors account for 1/3 of the market share of the entire air compressor market, especially in low and medium pressure applications.
Most of the practitioners in the air compressor industry in the country are focusing on screw air compressors. Because the air compressor industry is small and the knowledge system is complex, there are not many teaching institutions involved. The related knowledge of screw air compressor system and maintenance can only be obtained from the manufacturer or the master and the apprentice. This chapter focuses on practice and combines theory, highlights pertinence and practicability, and provides a way for the majority of air compressor maintenance personnel to learn and improve.
What is air?
The air is the atmosphere in which we live. Normal air is a prescribed value (different from country to country): it is called normal air when the pressure is 0.1MPa (or 1 standard atmospheric pressure), the temperature is 20℃, and the relative humidity is 36%.
What is normal air?
Normal air differs from standard air to be discussed later in temperature and humidity.
What is standard air?
The definition of air standard state is: air pressure is 0.1MPa (or 1 standard atmosphere), temperature is 0°C, and humidity is 0%. The air in this state is called the standard state of air.
Definition of the standard state of air?
In the standard state, the density of air is 1.185kg/m. If this is used as the unit of air compressor flow rate and dryer throughput, it should be written as Nm/min (commonly known as the standard square).
What is atmospheric pressure?
The pressure caused by the thick atmosphere surrounding the earth's surface on the earth's surface or surface objects is called atmospheric pressure.
What is absolute pressure?
The pressure directly acting on the surface of the container or object is called absolute pressure, and the absolute pressure takes absolute vacuum as the starting point.
What is gauge pressure?
The pressure measured with pressure gauges, vacuum gauges, U-tubes and other instruments is called gauge pressure, and the gauge pressure starts from atmospheric pressure. The relationship between the three: absolute pressure = gauge pressure + atmospheric pressure.