Air compressors perform a variety of functions in marine environments. The primary purpose of an air compressor is to take in air and compress it to decrease its volume and increase its energetic potential. When released from the marine air compressor tanks, the air is able to return to its original volume. This process provides additional power that can be directed to completing specific tasks.
There are four primary forms of marine air compressors, including:
- Centrifugal
- Reciprocating
- Rotary Screw
- Rotary Vane
The most common form of marine air compressor tends to be of the reciprocating variety, though others may be more appropriate for different functions, depending on their intended purpose.
Differences between Marine and Other Compressors
Marine air compressors are designed to function within the ship environment. Often, these machines need to withstand wet conditions, as well as the presence of salt in the water and air. Not all metals handle the conditions as well, so using an air compressor that isn’t designed for these specific conditions can result in device failure or even safety hazards.
Marine Air Compressor Uses
Compressed air can serve multiple functions designed to assist with ship operations. Often, each marine air compressor is maintained for a specific use. That helps determine appropriate sizing and power potential to ensure that the task at hand is properly managed.
Marine air compressors are normally separated based on the following uses:
- Main
- Deck
- Emergency
- Topping Up
Main Marine Air Compressor
The main air compressor on a ship provides power for starting primary and auxiliary engines. Pressurized air is stored in an appropriate tank, and released to provide the power necessary to start engine operations. Often, these compressors are high capacity, as it can require a significant amount of energy to start the engines.
Deck Marine Air Compressor
Marine air compressors have a variety of uses on the deck. Often, these are smaller systems that maintain a lower capacity. This helps ensure the systems are more portable. Air compressors can operate a variety of pneumatic power tools, allowing for certain ship repairs and other mechanical operations to be completed while out on the water. They also have functions related to cleanliness and sanitation.
A deck air compressor can also assist in certain safety activities. For example, they can operate emergency fire pumps in case of fire. Since ships out to sea are generally on their own during an emergency, having sufficient systems available to control situations like fires, are critical to the integrity and safety of the ship and safety of the crew.
Emergency Marine Air Compressor
As the name suggests, emergency air compressors provide a backup source of potential energy in case of an emergency. Often, they are designed to provide power to auxiliary engines should the main compressor fail.
Topping Up Marine Air Compressor
Marine air compressors are designed for topping up to help compensate for any leaks in the system. They are connected to monitoring devices that provide information on the current pressure within the system. When the pressure falls below a designated level, the topping up compressor works to restored the desired balance.
Operating Procedures
While each marine air compressor may have slightly different operating requirements (which will be dictated in the operator’s manual), certain requirements tend to be standard. Some of the common standards requirements include:
- Maintaining proper lubrication
- Valve unloading
- Pressure gauge cocks for avoiding excess pressure
- Air filtering processes
- Cooling water usage
- Relief valve operation
- Air line piping maintenance
Regular maintenance is based on specific time intervals. Certain procedures and checks are required daily or before using the marine compressor that is in a standby state. Others are completed after a certain number of running hours, such as 250 or 500 hours of operation.
Timed Maintenance
Marine air compressor timed maintenance requirements will either be dictated by the owner’s manual or the standards set by the parts manufacturer. Some maintenance activities involve cleaning and inspection tasks, while others require parts replaced. While the precise activities required are reviewed in the operator’s manual, here is an overview of some of the more common requirements.
Air filters need regularly cleaning to ensure proper operation of the compressor. Over time, contaminants will build up on the filter which inhibits air passage through the filter itself and into the tank. It can also raise the temperature of the air, which may pose a fire hazard.
Valves need to be cleaned, inspected regularly and replaced should damage be identified. The same advice pertains to drive belts, such as the v-belt. Damaged belts may fail and improperly fitted belts can slip.
Unloader operation must regularly be tested as well, and crankcase oil requires changing after certain usage periods. The frequency at which crankcase oil must be replaced varies depending on the oil being used. For example, synthetic oils often have longer usable life spans compared to their non-synthetic brethren.
Troubleshooting Processes
Certain issues in marine air compressors will affect their performance and can cause safety hazards. While problems can vary depending on the compressors use and ship conditions, some common issues can be managed with simple troubleshooting. While these are not all of the problems that can be experienced, this overview can be useful for identifying the causes of certain operational issues:
- Low-pressure warnings can be caused by leakage, as well as a choked suction strainer. Faulty pressure gauges and a low level of available oil can also trigger the warning.
- High-temperature warnings related to the cooling water can occur when the associated valves are closed. Faulty cooling water pumps may also be responsible, as well as low water levels. Pipe blockages and damaged belts are also possible causes.
- Excessive noise during operation of the marine air compressor can have a variety of causes. Worn bearings and piston rings can increase the amount of noise created. Issues relating to the valves, including poor seating and damaged or broken pieces, may also be responsible.
Before troubleshooting any issue or performing any maintenance activities, it is important to consult the operator’s manual regarding recommended procedures and basic safety precautions. Failure to do so could result in additional damage as well as a violation of safety hazards for the person troubleshooting the equipment.