Compressor is one such device which is used for quite a lot of purposes on a ship. As the main objective of the compressor, as the name proposes, is to compress air or any fluid in order to reduce its volume. Some of the main applications of compressors are main air compressor, deck air compressor, AC compressor and refrigeration compressor. In this post we will learn about air compressors and its types.
Air Compressor creates pressurized air by decreasing the volume of air and in turn increasing its pressure. Different types of air compressors are used according to the usage.
Types of Air Compressors
There are primarily four types of compressors:
Rotary vane compressor
Rotary screw compressor
Reciprocating air compressor
Though, on ship reciprocating air compressor is widely used.
Uses of Air Compressor on Ship
On board a ship, compressed air is used for numerous purposes. On the basis of application, different air compressors are kept for a particular usage. Normally, air compressors on board ships are:
main air compressor
topping up compressor
deck air compressor
Emergency air compressor
Main air compressor
Main air compressor is used for supplying high pressurized air for starting of main and auxiliary engines. The pressurized air produced by the air compressor is stored in air storage bottle. These are high capacity compressors and the air pressure that is needed from these compressors to start the main engine is 30 bars.
Control air is also delivered from air bottle through a pressure reducing valve and a control air filter. Normally they are twice in number and can be more than that for redundancy.
READ ALSO: WHAT TO KNOW ABOUT SHIP SCAVENGE FIRES
Topping up compressor
Topping up compressor takes up the lead to cover up for the leakage in the system. This means that as soon as the air pressure in the system goes below a particular level, the topping up compressor replenished the system with pressurized air.
Deck air compressor
Deck air compressor is used for deck use and as service air compressor and might have a distinct service air bottle for the same. These are lower capacity pressure compressors as pressure needed for service air is in between the range of 6 to 8 bar.
Emergency air compressor
Emergency air compressor is used for starting auxiliary engine at the time of an emergency or when the main air compressor has failed for filling up the main air receiver. This type of compressor can be motor driven or engine driven. If motor driven, it should be supplied from emergency source of power.