How to distinguish between an air compressor and a compressor

I. Different Concepts: An air compressor is a mechanical product primarily used for compressing air and can be used in many places. For example, one of the most common functions of an air compressor is to compress air for use as power, which is widely used in the power industry. In addition, it can also be used for cooling and separating gases, transporting gases, etc., playing a very important role in life and work.

A compressor is a general term. There are many types of compressors, such as refrigeration compressors, hydrogen compressors, and air compressors. An air compressor is just one type of compressor. Its compression medium is air, and compressors can be used to compress many things, not just air. Therefore, the difference between an air compressor and a compressor is like the difference between a Chinese person and a human being. A Chinese person belongs to the category of humans. An air compressor is included in the general concept of a compressor and is one type of compressor.

II. Different Working Principles of Air Compressors: Taking a screw air compressor as an example, the working cycle of a screw compressor can be divided into three processes: intake (1), compression (2, 3), and exhaust (4). When the rotor rotates, each pair of meshing teeth successively completes the same working cycle. 

1.Intake Process: When the rotors rotate, the tooth space between the male and female rotors is at its maximum when they turn towards the intake end wall opening. At this time, the tooth space of the rotors connects with the intake port. Since the gas in the tooth space is completely discharged during the exhaust process, the tooth space is in a vacuum state when exhaust is complete. When the rotors turn towards the intake port, external gas is drawn in and enters the tooth space of the male and female rotors axially. When the gas fills the entire tooth space, the end face of the rotor inlet side turns away from the intake port of the housing, and the gas in the tooth space is sealed.

2. Compression Process: When the suction of the male and female rotors ends, the tips of the teeth of the two rotors close with the housing, and the gas does not flow out from the tooth space. The mating surfaces gradually move towards the exhaust end. The tooth space between the meshing surface and the exhaust port gradually decreases, the gas in the tooth space is compressed, and the pressure increases.

3. Exhaust Process: When the meshing end face of the rotor connects to the exhaust port of the housing, the compressed gas begins to be discharged until the meshing surface of the tooth tips and tooth spaces moves to the exhaust end face. At this point, the gap between the meshing surfaces of the male and female rotors and the tooth grooves of the exhaust port of the casing is zero, indicating that the exhaust process is complete. Simultaneously, the tooth groove length between the rotor meshing surfaces and the air inlet of the casing reaches its maximum value, and the intake process resumes.

Compressor Working Principle: Taking a typical centrifugal compressor as an example, a turbine (or motor) drives the compressor's main shaft impeller to rotate. Under centrifugal force, the gas is thrown into the diffuser behind the impeller, forming a thin zone in the middle of the impeller. The gas in front enters the impeller from the steam inlet section in the middle of the impeller. As the impeller rotates continuously, the gas can be continuously discharged, thus maintaining a continuous flow of gas in the air compressor. The gas pressure increases due to centrifugal force, and it can also leave the impeller at high speed. The gas velocity gradually decreases as it passes through the diffuser, converting kinetic energy into static energy, further increasing the pressure. If the pressure obtained by one impeller is insufficient, multiple impeller stages can be connected in series to meet the outlet pressure. The series connection between stages is achieved through bends and reflux devices. This is the working principle of a centrifugal compressor.