- SOLAS Chap II-1, Part C – Machinery Installations, Regulation 27, Item 4
- Internal combustion engines of a cylinder diameter of 200 mm or a crankcase volume of 0.6 m3 and above shall be provided with crankcase relief valves of a suitable type with sufficient relief area.
- SOLAS Chap II-1, Part E – UMS Regulations, Regulation 47, item 2
- Internal combustion engines of 2,250 kW and above or having cylinders of 300 mm bore shall be provided with oil mist detectors.
- Larger engines (>300 mm cylinder diameter) require one relief valve on each crankcase door
- Smaller engines (≤300 mm cylinder diameter) may have relief valves at the crankcase ends
- The combined free area of valves must be at least 115 cm2/m3 of crankcase gross volume
- Minimum free area should not be smaller than 45 cm2.
Crankcase Relief Valve Installation and Placement
The number and placement of relief valves depend on engine size:
→ Engines with cylinders 200-250 mm bore: At least two valves, located at or near crankcase ends.
→ Engines with cylinders 250-300 mm bore: One valve per alternate crank throw, minimum of two valves.
→ Engines with cylinders >300 mm bore: One valve per main crank throw.
Crankcase Relief Valve Maintenance and Safety:
Key maintenance points include:
→ Regular inspection for leaks during engine operation
→ Replacement of O-rings if leaks occur
→ Visual inspection of flame arresters after any work that could cause mechanical damage
→ Complete replacement of flame arresters after a crankcase explosion
Inspection:
State the procedure for crankcase inspection
.crankcase inspection .cc inspection
Purpose:
To look for early sign of failure
Preparation:
· Tool box meeting carried out.
· Carry out proper risk assessment and work permit taken
· Enclosed space entry permit to be taken and enclosed space entry procedure to be followed
· Inform bridge and put warning notice at ECR
· Block the starting mechanism and stop L.O pump
· Open indicator cocks and engage turning gear
· Propeller clearance taken
· Turning gear must be operated by only in remote mode
· All personnel involved should not have any object in their pocket
· Instrument/tools to be used should be checked and counted
Procedure:
Starting from the top
1. Check stuffing box arrangement
· Ensure locking wires and bolts are intact
· Check drainpipe is clear
2. Check crosshead bearing for any sign of wiping
3. Check cross guide shoes for any abnormal sign of scoring
4. Check lube oil telescopic pipe for any sign of leakage due to loosen connection
5. Check bottom end bearing bolts and nuts for any slackness and sign of wiping
7. Check crank web and journal of crankshaft (semi-built type) for any sign of slippage comparing to the reference mark provided
8. Check main bearing bolts for slackness and sign of wiping
9. Check tie rods for slackness
10. Check transverse girder for any cracks if any doubt carry out die penetrant Check
11. OMD sampling cup for blockage
12. Check crankcase relief valve gauge for dents, wetness, and form of clogging
13. Check crankcase floor and drain traps for any metallic debris present
14. Close all unit crankcase door and start lo pump
· One at a time open the crankcase door to inspect the oil flow pattern comparing to the other unit. Flow pattern will differ when there is a reduction of LO flow or early sign of bearing failure
· Check crosshead lube oil piping linkage for leakages if possible
· For chain gear compartment check the oil spray nozzle for any change in oil flow and the condition of rubber guide and clearance.
· For chain thrust bearing check oil nozzle for clogging and flow pattern