Leakages in lube oil system.
Large scale repeated leakages in lube oil system especially pipe lines and hoses in locomotives has become point of extreme concern. Review of recent failures indicates systematic recurring weakness in following areas.
LUBE OIL SYSTEM FAILURE
ITEMS
Sub Assembly Pipings/Joints Gasket Stud & Clamp Total
Centrifuge 1 2 3 6
Strainer 2 1 3
Turbo 1 1
L/Oil cooler 1 3 4
Regulating valve 3 3
Lube oil filter 2 2
Engine Governor 2 2
Drain pipe 1 1
Turbo Filter casing crack 1
Total 13 6 3 23
Preventive measures as outlined below must be started by shed with immediate effect.
Check list containing identified leak prone points as mentioned above should be prepared. Special attention should be paid on pipe lines and joints of strainer, centrifuge, turbo & lube oil cooler. A drive should be launched to check condition of lube oil system in every schedule.
Loco must be cleaned thoroughly and power-pack should be wiped clean and kept dry. No oozing, seepage should be permitted from any joint. Leakages can be detected only on clean background
Lube oil hoses should be replaced/ recertified in M12 and above schedules.
Lube oil hoses kit for non abrasive hoses should be stocked and used by sheds.
Old end fittings should not be reused by sheds. Only hose pipe with integral end fittings should be used. All rubber hoses along with end fittings should be hydraulically tested under water at 10 kg / cm2 air pressure
Hose coupling threads must be cleaned, degreased and coated with thread locking compound before assembly.
Piping: The layout of pipe line should be laid in stream line fashion exactly similar to DLW manufactured/DMW RPP locos. There should not be any sharp bend or rubbing in pipe lines. T gauge should be used for ensuring correct gap and alignment for joining pipe.
Clamping: All clamps are to be renewed during major schedules. Welding over existing welding should not be resorted to. Clamps should be rigidly fixed and soft Gasketting material should be used before clamping pipes/hoses
Colour matching of surface: Whenever two surfaces are to be joined either with or without gasket, proper lapping and colour matching of surface should be ensured. Surface condition should be checked and restored if required.
Gaskets: Condition of old gasket will yield valuable clue regarding poor surface condition, sharp edges, over tightening and premature perishing. Causes of these should be attended before new gasket is fitted. Gasketting compound should be used for attending surface imperfections. Gasket must be visually examined and tightened uniformly.
Over tightening: Whenever any leakage is observed in shed, staff simply over tighten the component and allow it in service. No over tightening should be permitted, if leakage is observed then component should be dismantled and cause of leakages, damaged thread, surface or gasket should be attended.
Leakage checking: Leakages are best checked when loco is on load box test and run for some time. Lube oil leakage tendency is very high at higher temperature due to reduction in viscosity at elevated temperature. Crank case exhauster motor can be stopped for 30 seconds and lube oil leakages can be observed.
Training and acceptance level: Sectional staff and supervisors must be trained and counseled to ensure leak free locomotives. Significance of the objective must be understood by all of them.
Progress of the drive and action taken should be monitored.
Annexure
Hose and Fitting care
Component Inspection: Prior to assembly, a careful examination of the hose and fittings must be performed. All components must be checked to ensure that they are the correct type, size, and length. The hose must be examined for cleanliness, obstructions, blisters, kinks, cracks, cuts or any visible defects. The fitting and sealing surfaces need to be inspected for burns, nicks, corrosion or other imperfections.
Minimum Bend Radius: Particular attention must be given to prevent sharp bends at the hose connection to the fitting. Any bending during installation to less than the minimum bend radius should also be avoided.
Proper Connection of Ports: Proper physical installation of the hose assembly requires a correctly installed port connection ensuring that no twist or torque is transferred to the hose when the fittings are being tightened.
Elbows and Adapters: These are provided to relieve hose strain. Only lab tested forged component should be used.
Routing: The hose assembly should be routed in Stream line manner.
Hydraulic Hose Assembly Care
Lengths: Unnecessarily long hoses can increase pressure drops and affect system performance. When pressurized, a hose that is too short may pull loose from its fittings, or stress the fitting connections causing premature failures.
Visual Inspection: Any of the following conditions require immediate shut down and replacement of the hose assembly:
· Fitting slippage on hose.
· Damaged, cracked or charred hose.
· Cracked, damage or badly corroded fittings.
· Leaks at fitting or in hose.
· Kinked, crushed, flattened or twisted hoses.
· Blistered, soft, degraded or loose covers.
Function Test: Operate the system at maximum operating pressure and check for possible malfunctions and leaks.
Hydraulic System Storage and Protection
Hose Sleeves: Sleeves are designed to protect hoses from abrasive wear and other hostile conditions. They simply slip over the end of a hose assembly, or they may be spilt to allow them to be installed around a hose assembly already on equipment. Hose covers are generally made of high strength fabric, and coated with appropriate materials to resist chemicals, heat, particles, moisture etc.
Hose storage: Temperature, humidity, ozone, sunlight, oils, solvents, corrosive liquids, insects, rodents, and radioactive materials can adversely affect hose products. Hoses should be stored in a dark, dry atmosphere away from heat sources, electrical equipment, and the above adverse elements. The ideal storage temperature for rubber hose is +50°F (10°C) to +70°F (21°C), with a maximum of 100°F (38°C). The date of manufacture of the hoses also needs to be checked.
Hose Storage Life: Hoses must be replaced in M24 & above schedule. No hose older than one year should be fitted.
Hydraulic Hose Assembly Care
The date of manufacture of hoses is generally marked on the hose and other information is provided, for example:
· R1 ~ 2Q/05 marked on a hose shows it is a single wire construction hose made in the 2nd quarter of 2005
· R2 ~ 4Q/05 would denote a two wire construction hose made in the fourth quarter of 2005.
Tips on Hose Assembly Care and Maintenance
Always clean fittings before connection.
Always ensure caps and plugs are fitted on hoses when not in use.
Store hoses out of sunlight. Hoses left in direct sunlight will degrade and high pressures will be generated when oil expands in hose making connection difficult.
Use protective tape, anticorrosive coating to protect fittings from corrosion.
.
Large scale repeated leakages in lube oil system especially pipe lines and hoses in locomotives has become point of extreme concern. Review of recent failures indicates systematic recurring weakness in following areas.
LUBE OIL SYSTEM FAILURE
ITEMS
Sub Assembly Pipings/Joints Gasket Stud & Clamp Total
Centrifuge 1 2 3 6
Strainer 2 1 3
Turbo 1 1
L/Oil cooler 1 3 4
Regulating valve 3 3
Lube oil filter 2 2
Engine Governor 2 2
Drain pipe 1 1
Turbo Filter casing crack 1
Total 13 6 3 23
Preventive measures as outlined below must be started by shed with immediate effect.
Check list containing identified leak prone points as mentioned above should be prepared. Special attention should be paid on pipe lines and joints of strainer, centrifuge, turbo & lube oil cooler. A drive should be launched to check condition of lube oil system in every schedule.
Loco must be cleaned thoroughly and power-pack should be wiped clean and kept dry. No oozing, seepage should be permitted from any joint. Leakages can be detected only on clean background
Lube oil hoses should be replaced/ recertified in M12 and above schedules.
Lube oil hoses kit for non abrasive hoses should be stocked and used by sheds.
Old end fittings should not be reused by sheds. Only hose pipe with integral end fittings should be used. All rubber hoses along with end fittings should be hydraulically tested under water at 10 kg / cm2 air pressure
Hose coupling threads must be cleaned, degreased and coated with thread locking compound before assembly.
Piping: The layout of pipe line should be laid in stream line fashion exactly similar to DLW manufactured/DMW RPP locos. There should not be any sharp bend or rubbing in pipe lines. T gauge should be used for ensuring correct gap and alignment for joining pipe.
Clamping: All clamps are to be renewed during major schedules. Welding over existing welding should not be resorted to. Clamps should be rigidly fixed and soft Gasketting material should be used before clamping pipes/hoses
Colour matching of surface: Whenever two surfaces are to be joined either with or without gasket, proper lapping and colour matching of surface should be ensured. Surface condition should be checked and restored if required.
Gaskets: Condition of old gasket will yield valuable clue regarding poor surface condition, sharp edges, over tightening and premature perishing. Causes of these should be attended before new gasket is fitted. Gasketting compound should be used for attending surface imperfections. Gasket must be visually examined and tightened uniformly.
Over tightening: Whenever any leakage is observed in shed, staff simply over tighten the component and allow it in service. No over tightening should be permitted, if leakage is observed then component should be dismantled and cause of leakages, damaged thread, surface or gasket should be attended.
Leakage checking: Leakages are best checked when loco is on load box test and run for some time. Lube oil leakage tendency is very high at higher temperature due to reduction in viscosity at elevated temperature. Crank case exhauster motor can be stopped for 30 seconds and lube oil leakages can be observed.
Training and acceptance level: Sectional staff and supervisors must be trained and counseled to ensure leak free locomotives. Significance of the objective must be understood by all of them.
Progress of the drive and action taken should be monitored.
Annexure
Hose and Fitting care
Component Inspection: Prior to assembly, a careful examination of the hose and fittings must be performed. All components must be checked to ensure that they are the correct type, size, and length. The hose must be examined for cleanliness, obstructions, blisters, kinks, cracks, cuts or any visible defects. The fitting and sealing surfaces need to be inspected for burns, nicks, corrosion or other imperfections.
Minimum Bend Radius: Particular attention must be given to prevent sharp bends at the hose connection to the fitting. Any bending during installation to less than the minimum bend radius should also be avoided.
Proper Connection of Ports: Proper physical installation of the hose assembly requires a correctly installed port connection ensuring that no twist or torque is transferred to the hose when the fittings are being tightened.
Elbows and Adapters: These are provided to relieve hose strain. Only lab tested forged component should be used.
Routing: The hose assembly should be routed in Stream line manner.
Hydraulic Hose Assembly Care
Lengths: Unnecessarily long hoses can increase pressure drops and affect system performance. When pressurized, a hose that is too short may pull loose from its fittings, or stress the fitting connections causing premature failures.
Visual Inspection: Any of the following conditions require immediate shut down and replacement of the hose assembly:
· Fitting slippage on hose.
· Damaged, cracked or charred hose.
· Cracked, damage or badly corroded fittings.
· Leaks at fitting or in hose.
· Kinked, crushed, flattened or twisted hoses.
· Blistered, soft, degraded or loose covers.
Function Test: Operate the system at maximum operating pressure and check for possible malfunctions and leaks.
Hydraulic System Storage and Protection
Hose Sleeves: Sleeves are designed to protect hoses from abrasive wear and other hostile conditions. They simply slip over the end of a hose assembly, or they may be spilt to allow them to be installed around a hose assembly already on equipment. Hose covers are generally made of high strength fabric, and coated with appropriate materials to resist chemicals, heat, particles, moisture etc.
Hose storage: Temperature, humidity, ozone, sunlight, oils, solvents, corrosive liquids, insects, rodents, and radioactive materials can adversely affect hose products. Hoses should be stored in a dark, dry atmosphere away from heat sources, electrical equipment, and the above adverse elements. The ideal storage temperature for rubber hose is +50°F (10°C) to +70°F (21°C), with a maximum of 100°F (38°C). The date of manufacture of the hoses also needs to be checked.
Hose Storage Life: Hoses must be replaced in M24 & above schedule. No hose older than one year should be fitted.
Hydraulic Hose Assembly Care
The date of manufacture of hoses is generally marked on the hose and other information is provided, for example:
· R1 ~ 2Q/05 marked on a hose shows it is a single wire construction hose made in the 2nd quarter of 2005
· R2 ~ 4Q/05 would denote a two wire construction hose made in the fourth quarter of 2005.
Tips on Hose Assembly Care and Maintenance
Always clean fittings before connection.
Always ensure caps and plugs are fitted on hoses when not in use.
Store hoses out of sunlight. Hoses left in direct sunlight will degrade and high pressures will be generated when oil expands in hose making connection difficult.
Use protective tape, anticorrosive coating to protect fittings from corrosion.
.
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