Marine Air Compressors – An In-depth Guide 


Air compressors are eminent equipment in marine vessels primarily used to compress gases for diverse purposes. The compressed air stored in tanks on a ship serves multiple applications. But when it comes to choosing marine air compressors for a watercraft, there are various types of compressors to address specific needs on board.

In this blog post, we present an overview of various types of air compressors and their significance in vessel operation.

Types of Marine Air Compressors and Their Uses

#1. Main Air Compressor 

The main air compressor is a high-capacity compressor equipped with large air storage units. These compressors are continuously in operation on the ship to supply high-pressure air at 30 bars or more to operate the main engine. This equipment features a control air filter and pressure-reducing valve for supplying control air to the main engine.

Applications: The main air compressors supply power for starting and regulating the primary and auxiliary engines in the watercraft.

#2. Service Air Compressor 

These marine air compressors compress air at 7-8 bar pressure to support low-pressure applications on the ship.

Applications: The low-pressure compressed air is a.k.a. filtered service air (control air). This air is 100% clean and free of moisture and oil traces for various operations.

First, compressed air at 7-8 bars is ideal for remote control pneumatic systems for operating ship onboard machinery.

Second, low-compressed air is necessary for engine control systems and tank gauging operations.

Third, these compressors support air supply to the temperature and pressure controls.

Fourth, low pressure is an integral element for operating LNG/LPG cargo instruments, cargo pumps turbine governors, etc.

#3. Reciprocating Air Compressor/ Piston Air Compressor  

These positive displacement type air compressors feature a crankshaft attached to the pistons and cylinders with connecting rods, suction valve, discharge valves, and a wrist pin. The compressor sucks large volumes of air into the compression chamber and the crankshaft drives the piston to compress the air.

There are two types of reciprocating air compressors – single-stage and multi-stage. The multi-stage reciprocating compressors are configured to support operations in large ships.

Applications: Reciprocating air compressors support the pneumatic tools on board.

#4. Emergency Air Compressor

Emergency air compressors are small-sized compact devices used to drive power to the engine from the emergency switchboard. The system is connected to an emergency air bottle and engine. These compressors can be configured to motor-driven or engine-driven systems in ships. This lifesaving compressor offers a backup power supply during a power failure.

Applications: Supplies backup power to start the primary and auxiliary engines during power outages.

#5. Deck Air Compressor 

As the name suggests, this air compressor meets the deck power requirements. The portable equipment is connected to a small air storage bottle to produce low-pressure compressed air (6-8 bars).

Applications: Used for supplying compressed air to the deck hose connections, regulating power for running repair tools, operating fire pumps, etc.

#6. Topping Up Air Compressor 

The topping-up air compressor is a safety device to protect the vessel during instances of air leaks. This compressor is connected to the air pressure monitoring system. It creates the required air pressure balance whenever the pressure drops below the normal level.

Applications: The topping-up compressors maintain the required air pressure during air leaks in the engine room. It protects the watercraft from damage caused by air leakage below the deck.

#7. Rotary Screw Air Compressor 

The rotary screw air compressor has two lubricated rotors (helical screws) rotating in opposite directions to compress the air passing through them. This mechanism with an integrated cooling system works on the principles of positive displacement. It passes the air to a compact chamber where the volume is reduced to create high pressure. This compressed air can be stored in a bottle for diverse applications.

Applications: Ideal for producing power up to 350 HP for diverse marine applications.

Looking for air compressors for your vessel?

Alfa Marine Spare Parts sells marine air compressors from leading brands worldwide. Contact us with the compressor part number/model to find the exact match. Get a custom quote from our friendly and knowledgeable staff within 24 hours.


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