In terms of classification, what category does an air compressor belong to?

The classification of air compressors within the industrial system

An air compressor (commonly referred to as an air compressor) is the core equipment that provides compressed air power. In the standard industrial and national economic industry classification, air compressors are primarily categorized under…General-purpose machinery and equipmentMajor category. Specifically, it is further subdivided intoFluid machineryorGas compression machineryWithin the product category, it is typically classified under the intermediate category of “Manufacture of Pumps, Valves, Compressors, and Similar Machinery” in relevant manufacturing classification standards. As one of the “heart” components of industrial production, air compressors, along with water pumps, fans, and other equipment, belong to the category of basic general-purpose machinery and are widely used across various industrial sectors.

Main classification dimensions of air compressors

To meet diverse operating conditions and requirements, air compressors have been developed in a variety of types. Understanding their classification helps ensure more accurate equipment selection.

1. Classification by Operating Principle

This is the most fundamental classification of air compressors, which are broadly divided into two main types: positive-displacement and dynamic.

• Positive-displacement compressor: Gas pressure is increased by directly compressing the gas volume. Common types include piston, screw, vane, and scroll compressors. Among these, screw compressors are widely used in industry due to their high efficiency and operational stability.
• Dynamic compressor: Kinetic energy is converted into pressure energy by a high-speed rotating impeller. The main types include centrifugal and axial‑flow compressors, which are typically suited for specific industrial applications requiring high flow rates at medium to low pressures.

2. Classification by Lubrication Method

Depending on whether lubricating oil is used in the compression chamber, air compressors can be classified as:

• Oil-lubricated air compressor: During compression, lubricating oil is used for cooling, sealing, and lubrication. This type of equipment is relatively low-cost, with well-established maintenance procedures, making it suitable for routine industrial applications where high gas purity is not required.
• Oil-free lubricated air compressor: The compression chamber uses no lubricating oil, or employs special self-lubricating materials. The discharged gas is oil-free, making this equipment the preferred choice for industries with extremely stringent air quality requirements, such as food processing, pharmaceuticals, and precision electronics.

3. Classification by Cooling Method

The compression process generates substantial heat, so the cooling method is also an important classification criterion:

• Water-cooled air compressor: Utilizes recirculating cooling water to remove heat. It offers excellent cooling performance and low operating noise, making it well suited for high‑power, continuous‑operation facilities that have access to a reliable water supply.
• Air-cooled air compressorIt relies on a built-in fan and heat sink for air cooling. Easy to install and requiring no external water supply, it is commonly used in small- and medium‑power equipment or in areas with limited water access.

Equipment Selection and Category Application Recommendations

Clearly defining the product category and classification characteristics of air compressors is a prerequisite for making informed equipment selections. In practical procurement and application, users should comprehensively assess their air consumption, operating pressure, environmental conditions, and specific requirements for compressed‑air quality. For example, typical mechanical manufacturing plants often opt for oil‑lubricated screw compressors, whereas medical‑device manufacturers or food‑packaging lines must deploy oil‑free models. Appropriately matching the equipment type not only ensures production safety but also helps reduce long-term energy consumption and maintenance costs.