There are various structural types of marine air compressors, such as vertical and V-shaped, single-stage and multi-stage, single-cylinder or multi-cylinder, air-cooled and water-cooled, etc. The vertical structure is simple and widely used in small boats; The V-type has a small footprint and strong capabilities and is commonly used on warships. The multi-stage structure is more complex than the single-stage structure, with a larger weight and correspondingly higher exhaust pressure. Multi-cylinder operation is smoother than single-cylinder operation, with less vibration but also greater weight. Water cooling is more effective than air cooling, but air cooling equipment is simple and both are used on ships. On larger ships (especially ships), if they are diesel-powered ships, in addition to having two identical main air compressors, emergency air compressors driven by diesel engines should also be installed. Steam powered ships are generally equipped with medium or low pressure air compressors to supply compressed air for automatic boiler control and blowing, or for other auxiliary engines. In order to reduce the storage space of air cylinders, ships are generally equipped with high-speed and high-pressure air compressors to supply compressed air required for medium to high-speed diesel engine start-up, weapon launch, blowing, the rapid ascent of submarines, and balance.

An air compressor for ships is also known as a compressor. Energy conversion machinery using gas as working fluid. A mechanical device that compresses air into high pressure (usually above 0.3 MPa absolute pressure). Air compressors have various working principles, including reciprocating, rotary, centrifugal, etc. On board, compressed air is mainly used for starting and operating main and auxiliary diesel engines, as well as for air horns and other pneumatic tools, blowing tools, and other occasions. The gas consumption is relatively small, not used continuously, and the pressure is relatively high. Therefore, marine air compressors are mostly reciprocating. It drives the piston to move back and forth through a crank connecting rod mechanism, producing a volume change in the cylinder for the intake, compression, and discharge of air. Its structure mainly includes cylinder, piston, crank connecting rod mechanism, suction and exhaust valve mechanism, etc. Reciprocating air compressors can be classified into horizontal, vertical, inline, V-shaped, W-shaped, etc. according to the arrangement of cylinders; There are single cylinder and multiple cylinder types based on the number of cylinders; There are two types of cylinder cooling methods: water-cooled and air-cooled; According to the working space form formed by the piston in the cylinder, there are three types: single acting, double acting, and differential type; According to the number of compressions experienced by air, there are single-stage and multi-stage. The air compressors installed on board the ship are divided according to their mission: air compressors for operating main and auxiliary diesel engines, air compressors for pneumatic automatic control systems, and emergency air compressors with independent starting and running power (such as gasoline or diesel engines). Air compressors are the main equipment in salvage engineering. The compressed air generated by it is widely used as a gas source in rescue and salvage operations, such as using an air lift mud pump for mud removal and inflating the salvage float. The power mother machine is widely used in hydraulic engineering, civil engineering, bridges, mechanical manufacturing, and water transportation engineering for pneumatic tools (such as rock drills, air shovels, air picks, air drills, pneumatic grinding wheels, diver gas supply, etc.). It can also be used for inflation, pumping, and pressurization work. The oil-free air compressor is used for inflation and pressurization in precision automatic control and communication systems.

On diesel powered ships, compressed air is mainly used for starting and reversing diesel engines. After being depressurized, it is used as control air for automatic control of main and auxiliary equipment, as well as for supplying air to other auxiliary mechanical equipment that require compressed air (such as pressure water tanks, air horns, centrifugal pump self suction devices, etc.) and pneumatic tools. It is also used for cleaning parts, filters, etc. during maintenance work. Compressed air is provided by an air compressor and stored in an air bottle. Air compressors are important marine auxiliary engines.