TURBOCHARGERS CAN HAVE 2 TYPES OF BEARING SYSTEMS, NAMELY:-
- A BALL BEARING AND ROLLER BEARING SYSTEM IN WHICH THE TWO BEARINGS NAMED ARE AT THE EITHER ENDS OF THE ROTOR SHAFT.
- SLEEVE BEARING WHICH ARE PRESENT AT THE MIDDLE OF THE ROTOR SHAFT.
THE LUBRICATION SYSTEM IN BOTH OF THE BEARING SYSTEM IS DIFFERENT.
IN THE FIRST ONE BOTH THE BEARINGS CONSIST OF INDEPENDENT LUB OIL PUMPS WHICH ARE CONNECTED TO THE ROTOR SHAFT AND OPERATES WHEN THE TURBOCHARGER ROTATES. THESE ARE GEAR PUMP.
IN THE SECOND SYSTEM THERE CAN BE TWO TYPES OF LUB OIL SYSTEM PROVIDED. IN ONE SYSTEM LUB OIL IS SUPPLIED BY THE MAIN LUB OIL LINE BY THE HELP OF ENGINE’S MAIN LUB OIL PUMP. THIS LUB OIL GOES TO THE BEARING THROUGH A THROTTLE VALVE WHICH HELP IN ADJUSTING THE LUB OIL PRESSURE OF TURBOCHARGER, AND THIS OIL RETURN BACK TO THE SUMP.
IN THE SECOND ONE THE LUB OIL IS SUPPLIED FROM THE MAIN LUB OIL SYSTEM THROUGH THE GRAVITY TANK. THE OIL IS DISCHARGED TO THE MAIN LUB OIL BOTTOM TANK VIA SLEEVE BEARING. A SEPARATE TANK IS MOUNTED ON THE TOP OF THE TURBOCHARGER WHICH REMAINS FILLED UP BY LUB OIL FROM THE MAIN SUPPLY PIPELINE. IN THE EVENT OF FAILING LUB OIL SUPPLY DUE TO TRIP OR ANY OTHER DEFECT, ENGINE WILL BE SHUT DOWN BY SAFETY SYSTEM AT THAT TIME LUBRICATION OF THE HIGH SPEED ROTOR BEARING WILL BE CARRIED OUT BY THIS OVERHEAD TANK, UNTIL ROTOR COMES TO STOP. THIS TANK HAS A LEVEL ALARM WHICH WILL OPERATE WHEN LEVEL OF LUB OIL IN TANK STARTS FALLING. THIS PROTECTS IN CASE LUB OIL IS NOT GETTING FILLED TO THE TANK DUE TO ANY OTHER REASON.
