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Ship’s Service Air System

Service air system in ship

Partial Compressed Air System (Service Air System)
Partial Compressed Air System (source-

Pressured air on ships is used for a variety of purposes. The high-pressure air of 30 bar is used mainly for large engines to start. This high-pressure air is used to reduce the pressure of working through the pressure reduction pipes and is used for other important purposes. The air at the reduced pressure of 7-8 bar is used as the service air for most applications. Some of these include the launch of Auxiliary Engines, Emergency Generators, Freshwater and drinking water charging, fog blowing, spring engine exhaust valve Main, dry Main Engine turbocharger, used for cleaning sewage plants -aerobic sewage disposal, boiler spray, oil transfer air pumps and many other things such as air purifier for use in cleaning, painting works, grinding and operation of wind tools such as grinders, chisels etc. One very important branch of this air pressurized bar 7-8 is used as a control air. The control air is a filtered branch of the service air that is free from any moisture and oil contamination. This controlled air is used for air controls and is essential for the operation of shipping equipment. This makes the air line in the ship a very important factor in the operation of the ship. This document sheds light on the Ship’s airline in general, its key components and functionality. The complete air pressure line on the ship includes the Main High-pressure airline, service airline and control airline.

Main Air Compressor

The main air pressure is the heart of the airway. The air conditioner compresses the air by reducing its volume to increase its pressure. Air compressors can be of various types. They include mainly modern merchant ships equipped with air reciprocating air compressors with intercoolers and aftercoolers for automatic discharge and stabilization arrangements. The main air compressor capacity is displayed according to Free Air Delivery (FAD) and stated in cubic mtrs / hour. Free Air Delivery can be defined as the air volume emitted by a compressor for 1 hour, which could be incorporated if it was extended down to atmospheric pressure and cooled to room temperature.

Air Compressor, screw type
Air Compressor (screw type)


The release of a large air compressor is led to a large air bottle or pond that holds this compressed air in the top 30-32 bar. A ship can have 2 or 3 large air compressors depending on many factors such as the strength of each air compressor, the amount of air volume required for the start of the Main Engine, the air demand for that particular vessel etc.

Air compressor working

Piston air compressor is widely used in the ship’s hull. A reciprocating compressor is a piston, connecting rod, crank shaft, wrist pin, non-return valve and the exhaust valve.  The piston is connected to the upper and the lower side of the suction and discharge lines. As the crankshaft rotates, which in turn pushes on the piston. The downward moving piston to reduce the pressure in the main cylinder, and the pressure to open the inlet valve. The piston can be reduced by rotating the crankshaft, and is a low-pressure air to fill the cylinder. The piston is now an up-and-down movement, and an upward motion, starting to close the inlet valve. When the pressure of the air at a certain value is reached, the exhaust valve opens and the compressed air is starting to move the ball to the line, and is located inside the air cylinder. This is with compressed air in the air cylinder, can be used to control both the main and auxiliary engines in the future. The vessel can be both a single and a double piston air compressor.

Applications of Air Compressors

The air compressor is a device that has a wide application in almost all industries as well as households in Russia. In the maritime industry as well, the air compressor, can be used in the devices and equipments for a variety of systems. It can be used in many processes, ranging from the small to the cleaning process, filter for important tasks, such as the start of the main and auxiliary engines. The air compressor provides compressed air to reduce the amount of air, and this, in turn, increases the pressure. The different types of air compressors, which are used depending on their use. In more technical terms, an air compressor can be defined as a mechanical device, that is, the electrical and the mechanical energy is converted into pressure energy in the form of compressed air.

The compressor operates on principles of thermodynamics. According to the equation for a perfect gas, and without any kind of difference in temperature, when the gas pressure increases, the volume decreases. The compressor works on the same principle and produces compressed air, which is the some of the air, and the reduction of the volume leads to an increase in the pressure of the air, without any difference in the temperature.

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