2.8.1 Main Engine Lubricating Oil System
The Main Engine has its own lubricating oil systems, described as follows:
There are three separate lubricating oil systems:
1. Main lubricating oil system, which supplies lubricating oil under pressure from the sump to the crankshaft and crosshead bearings. It also supplies cooling oil to the piston cooling spaces and turbocharger bearings.
2. Camshaft lubricating oil system, which supplies oil under pressure to the camshaft bearings.
3. Cylinder oil system, which lubricates the cylinders and piston rings. It is a once through system.
Main Lubricating Oil System Main Lubricating Oil Pumps
No of sets: 2
Capacity: 165m3/h at 4.7 kg/cm2
Two vertical centrifugal pumps located aft of the main engine at engine room floor level, supply oil through non-return valves at a rate of 165 m3/h and a pressure of 4.7 kg/cm2. Oil is directed to all the main bearings, connecting rod and crosshead bearings plus other internal running gear, such as the camshaft chain drive, thrust bearing and turbocharger.
Oil from the crosshead is supplied to the cooling spaces of the piston, and down the connecting rods to the bottom end bearings. The oil drains from the crankcase back to the L.O. sump. One of the two pumps will normally be running, with the other pump on stand-by, set to start in the event of the failure of the running pump discharge pressure, or voltage failure.
The pumps discharge through a cooler where a 3-way valve controls the temperature by directing the oil through or bypassing the cooler. The oil is then passed through an automatic back flush filter before the oil is supplied to the main engine. The auto-filter automatically back-flushes itself when the pressure differential across it rises to 0.7 kg/cm2. An alarm is activated if the differential pressure reaches 0.9 kg/cm2. A bypass filter is supplied for use when the backflush filter is shut down for maintenance. Drains from all the bearings are led to the main engine sump.
Procedure for Operation of the Main Engine Lubricating Oil System a) Check the level of oil in the main engine sump and top up if
necessary.
b) Supply steam to the main engine sump heating coil.
c) Ensure all pressure gauge and instrumentation valves are open.
d) Set up valves as shown in the tables below:
Position Description Valve
Open No.1 L.O. Pump Discharge Valve RS28
Open No.2 L.O. Pump Discharge Valve RS29
Close Line Drain to Sump RS50
Open L.O. Inlet Valve to Cooler RS18
Open L.O. Outlet Valve from Cooler RS19
Open Auto Filter Inlet Valve RS23
Open Auto Filter Outlet Valve RS24
Close Auto Filter Bypass Filter Inlet Valve RS21 Close Auto Filter Bypass Filter Outlet Valve RS22 Open M.E. L.O. Inlet Valve
e) Start one main L.O. pump.
f) Put the auto backflush filter on line.
g) Lubricating oil is now being supplied to the piston cooling oil spaces, crossheads and bearings turbocharger bearings.
h) Supply cooling water to the L.O. cooler.
i) Switch other pump to standby.
j) Shut steam off the sump heating coil when the engine is in use.
Stuffing Box Drain System
Any leakage from the piston-rod stuffing box is drained to the stuffing box drain tank. When there is sufficient quantity, the oil is transferred to the adjacent circulating tank using the L.O. purifier or L.O. transfer pump.
Circulation is continued through the purifier until all impurities are removed.
The oil is then processed through the C.J.C. fine filter, either by circulating back to the circulating tank or to the main engine sump.
Camshaft Lubricating System
A separate lubricating oil system supplies lubricating oil at a rate of 98.3 l/min and at a pressure of 3.5 kg/cm2to the camshaft bearings and cam followers and exhaust valve actuators.
Two horizontal gear type pumps supply the oil through a cooler and filter to the camshaft lubricating oil supply rail. One of the two pumps will normally be running, with the other pump on standby, which will start in the event of running pump discharge pressure failure, or voltage failure.
The cooler is circulated with cooling water from the central low temperature fresh water cooling system. All oil supplied to the camshaft bearings is filtered in a duplex filter. In addition to this a C.J.C. fine filter circulates oil in the camshaft lubricating oil drain tank. The camshaft L.O. drains back to the camshaft L.O. sump tank through a magnetic filter.
Preparation for the Operation of the Camshaft L.O. System
a) Check the level of oil in the camshaft drains tank and top up if necessary.
b) Ensure all pressure gauge and instrumentation valves are open.
c) Set up valves as shown in the tables below:
Position Description Valve
Open No.1 Camshaft L.O. Pump Suction Valve RS9 Open No.1 Camshaft L.O. Pump Discharge Valve RS6 Open No.2 Camshaft L.O. Pump Suction Valve RS10 Open No.2 Camshaft L.O. Pump Discharge Valve RS7
Open Fine Filter Inlet Valve RS11
Open Fine Filter Outlet Valve RS12
Open L.O. Cooler Inlet Valve RS4
Open L.O. Cooler Outlet Valve RS2
Closed L.O. Cooler Bypass Valve RS3
d) Supply cooling water to the camshaft L.O. cooler.
e) Check the condition of the filters.
f) Switch the other pump to standby operation.
g) Start the fine filter circulating pump.
Cylinder Oil System
High alkaline lubricating oil is supplied to the main engine cylinders on a once through basis in order to lubricate the piston rings and to reduce wear and counteract the acidity of the products of combustion.
Each cylinder of the engine is fitted with six oil injection pumps which pump a measured quantity of cylinder lubricating oil on each stroke of the engine into injection ports through the cylinder walls in order to supply oil to the running surface of the cylinder liner. The oil is injected when the piston rings are passing the injection ports on the compression stroke. The flow to the cylinders is monitored by a no-flow alarm.
The oil is supplied under gravity and through filters from a daily use tank, which is topped up daily from one of the cylinder oil storage tanks. The storage tanks are filled from filling connections at the accommodation side-wall on both port and starboard side.
Preparation for the Operation of the Main Engine Cylinder Lubricating Oil System
a) Top up the cylinder oil storage tank. This can be done from the No.1 or No.2 storage tanks using the cylinder L.O. pump.
b) Note the reading of the tank for measuring purposes.
c) Set up the valves as in the table below.
Position Description Valve
Closed No.1 M.E. Cylinder Oil Storage Tank
Outlet Valve RS37
Closed No.1 M.E. Cylinder Oil Storage Tank
Outlet Valve RS36
Closed Daily Use Tank Bypass Valve
from Storage Tank RS51
Open Run Down Valve from Daily Use Tank RS32
Open Filter Inlet Valve RS43
Open Filter Outlet Valve RS45
d) Ensure the daily use tank outlet filters are clean.
e) Check the consumption on a daily basis. Ensure the consumption does not drop below the manufacturer's recommendations. False economy will result in excessive piston ring and cylinder wear and sticking rings.
f) Check the condition of liner and piston rings, especially during the running-in period. If there are any signs of dryness the consumption should be increased.
g) Ensure that all the cylinder oil injection points are receiving equal quantities.
Illustration 2.8.2a Stern Tube Lubricating Oil System
LAL
LAL
LAL
LAL HAL
PV
Key
Lubrication Oil US16
US17
US31
US31
US32
US32
US15 US9
US13 US12 US3
US8
US14
Stern Tube L.O Sump Tank PV P
P
P
P
PV
PV
US1 US2
US10 US11
Stern Tube Head Tank
Forward Seal Head Tank US4
Aft Seal Head Tank
Aft Seal Pump
Circulating Pumps (0.5m3/h) US7
US6 US5
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
To L.O.
Transfer and Purifying Systems Stern Tube
Pump (0.5m3/h) N.C.
US33 US33
2.8.2 Stern Tube Lubricating Oil System
The stern tube is lubricated by its own L.O. system.
The stern tube is sealed by a set of lip seals at the forward and aft end.
An aft seal L.O. circulating pump feeds the oil chamber between No.2 and No.3 seal rings at the top of the chamber. The oil returns to the aft seal tank from the bottom of the chamber.The tank overflows back to the sump tank. The head of the seal tank is sufficient to prevent ingress of sea water. The aft seal header tank is filled from the stern tube header tank.
The forward seal is naturally circulated through its own header tank and is separate from the main stern tube system.
The stern tube bearing has its own L.O. circulation system in order to keep the bearing both lubricated and clean.
The header tank is filled from the stern tube L.O. tank using the stern tube transfer pump. The header tank overflows to the stern tube sump tank via a sight glass.
This tank has a suction to the L.O. purifier or L.O. transfer pump for purifica-tion direct or transfer to the M.E. L.O. settling tank. The purifier discharges back to the sump tank. The L.O. tank can be topped up from the M.E. L.O.
storage tank, or can be drained during refit.
Procedure for the Preparation of the Stern Tube L.O. System a) Ensure that all instrumentation valves are open.
b) Set valves as shown in the tables below:
Aft Seal
Position Description Valve
Open Aft Seal Circulating Pump Discharge Valve US6 Closed Aft Seal Circulating Pump Bypass Valve US7 Open Aft Seal Circulating Pump Suction Valve US5
Open Aft Seal Return Valve US8
Closed Header Tank Filling Valve US4
Closed Drain from Tank US9
Forward Seal
Position Description Valve
Open Outlet from Forward Seal Header Tank US10 Open Inlet to Forward Seal Header Tank US11 Stern Tube
Position Description Valve
Open Outlet Valve from Sterntube Header Tank US3
Closed Drain to L.O. Sump Tank US14
Open Inlet to Stern Tube US16
Open Outlet from Stern Tube US1
Open Inlet to Stern Tube Header Tank US2
Closed Drains from Stern Tube US15 & US17 c) Start the aft seal circulating pump.
Stern Tube Bearing Circulating System
Position Description Valve
Open Inlet to filters US33
Open Outlet from filters US33
Open Both Circ. Pumps Suction Valves US32
Open Both Circ Pumps Discharge Valves US31
d) Start one circulating pump and place the other on automatic start.
e) Check the L.O. tank level by operating the self-closing valves at the top and bottom of the tank gauge glass. If necessary replenish the tank by supplying L.O. from the stern tube L.O. tank via the stern tube transfer pump.
f) Check the system for water at regular intervals.
g) Take sample for analysis from the sampling cock at regular intervals.
The system is continuously operated, as above, both in port and at sea.