WHAT ARE THE SAFETY FEATURES IN AIR COMPRESSORS?
ANS) Every Air compressor on a ship is fitted with several safety features to avoid abnormal and dangerous operational errors of the equipment. If safety, alarms and trips are not present on the air compressor, abnormal operation may lead to breakdown of the compressor and may also injure a person working on or around it.
Relief valve: Fitted after every stage to release excess pressure developed inside it. The setting of the lifting pressure increases after every ascending stage.
Bursting disc: A bursting disc is a copper disc provided at the airside of the compressor. It is a safety disc, which bursts when the pressure exceeds over the pre-determined value.
Fusible plug: Generally located on the discharge side of the compressor, it fuses if the air temperature is higher than the operational temperature. The fusible plug is made up of material, which melts at high temperature.
Lube Oil low-pressure alarm and trip: If the lube oil pressure goes lower than the normal, the alarm is sounded followed by a cut out trip signal to avoid damage to bearings and crank shaft.
Water high temperature trip: If the intercoolers are choked or the flow of water is less, then the air compressor will get over heated. To avoid this situation high water temperature trip is activated which cut offs the compressor.
Water no-flow trip: If the attached pump is not working or the flow of water inside the intercooler is not enough to cool the compressor then moving part inside the compressor will get seized due to overheating. A no flow trip is provided which continuously monitor the flow of water and trips the compressor when there is none.
Motor Overload trip: If the current taken by motor during running or starting is very high then there is a possibility of damage to the motor. An overload trip is thus fitted to avoid such situation.
High Air Temperature Trip