Lets understand about main engine lubrication system

Main lubrication system consists of storage tanks for lubricating oil. they are fitted at higher levels in the engine room to bunker the oil easily. The arrangement provides a positive head to the system.

Main engine lubricating oil sump receives oil from the storage tank. Main lubricating oil supply pump takes suction from the sump and supplies it to main bearings, crosshead guides, guide shoes and other components of the engine.

Repeated use of the oil makes it hot and dirty. It is cleaned by a set of purifiers. the temperature of the oil is brought down to the working levels by coolers. They can either be shell and tube type or plate type. The three way valve regulates the temperature of the oil entering the engine. It is placed just after the cooler and allows part of the oil to bypass without being cooled. Auto backwash filter is one of the critical elements in the system. This ensures that clean oil enters the bearings and other working parts, which have fine running clearances. Debris in the oil chokes the passages of flow. hence, the oil that is drained from the stuffing box of the engine cannot be reused directly. A CJC filter is used to filter the oil. further, purification is carried out by the centrifuges to make the oil reusable. 

Lets see how they can be connected together to work as a system :

The hand pump transfers cylinder oil in the storage tank to the service tank. from here the oil flows to the engine driven lubricators by gravity.

The main engine lubricating oil pump takes suction from the lubricating oil sump tank through a duplex strainer. It supplies the oil to the main engine through a cooler and auto backwash filter.

From the stage tank lubricating oil is transferred to the lubricating oil sump tank by gravity, as and when required.

The purifier feed pump takes suction from the lubricating oil sump tank and supplies it to the purifier through a heater.

The purified oil is delivered back to the sump.

The used oil from the stuffing box is drained to the dirty oil tank. the purifier purifies the dirty oil and transfers it to the clean oil tank.

The CJC filter further purify this oil and transfers it to the lubricating oil sump tank.

Operating conditions :

In any dynamic system, the process is reflected by its parameter.

Any parameter deviating in value from its normal levels will signify a change in the system process.

For example, if the temperature of oil at engine inlet is higher than normal,it indicates a wrong setting on the viscosity regulator.

If the pressure of the oil at engine inlet is lower than normal, it indicates a clogged filter.

Safety features :

Safety devices warn the operator of any deviation.

The highlighted devices of the system act as front line safety provisions, which trigger the actual safety alarms, shut downs or isolation.

Temperature transmitters, pressure transmitters, level transmitters also provide first level of protection against system break downs.