1.6 Compress air and Auxiliary purpose

Before any work is commenced electric power must be turned off at the starter panel and the main switch board and the switch on the main switch board must be marked with a notice (repair work is in progress)

The discharge valve must be closed and the pressure must be released in all pressurized part of the compressor.

The safety valve, bursting disc (safety plate) and other safety equipment must be fitted and inspected regularly.

The compressor must never be used if the safety equipment is defective.

The usage of the compressed air on board is 

• Starting air system (both direct air admission and using air motor)

• Pneumatic control system

• As a power source for machinery and tools

• For miscellaneous services such as Ship whistle, boiler soot blowing,

Instrument reading is very important for duty watch man. During watch keeping duty, air pressure must be checked in the control room and near the air bottle and must understand which air bottle is in used and which one is reserved for emergency used.

• Watch man should know running compressor and standby compressor

• Check starting and stopping pressure of each compressor

When air compressor is starting all unloader valves should be opened. At that moment the motor ampere is low. The motor ampere is coming high, when the unloader valves are closed. The duty watch man must know correct ampere.

When compressor is starting the watch man must check 1st stage (low pressure) side and 2nd stage (high pressure) which can see in the pressure gauge.

• Check air temperature before and after intercooler and cooling water in and out temperature

• Check air temperature before and after aftercooler and cooling water in and out temperature

• Check Sump oil level

• Check lube: oil pressure

• Check lube: oil drip lubrication

• Check air compressor air system leakages

• Check air compressor condition during running means, noisy or vibration

• Check air compressor running hour 

• Check safety equipment (safety valve, safety plate (bursting disc), fusible plug if fitted.

If it is found any abnormal, should inform to duty engineer immediately without hesitant.

During air compressor is running, if it is found that suction and discharge valve for low pressure side and high pressure side are not working properly. 

Safety valve can be opened 

Compressor running time more than normal means, very close to overhauling time. 

Compressor is running but air bottle pressure is not coming up or may be air pressure going down

High air temperature can cause explosion.

Low lubrication oil pressure can cause excessive damage