ENGINEMAN 1 & Cand dirt when new gears or bearings are wearingin or after they have been opened for inspection.Lint or dirt, if left in the system, may clog theoil spray nozzles. The spray nozzle passages mustbe open at all times. Spray nozzles should not bealtered without proper authorization.Although the lubricating oil strainers performsatisfactorily under normal operating conditions,they cannot trap particles of metal and dirt whichare fine enough to pass through the mesh. Thesefine particles can become embedded in the bear-ing metal and cause wear on the bearings andjournals. These fine abrasive particles passingthrough the gear teeth act like a lapping com-pound and remove metal from the teeth.EFFECTS OF WATER AND ACID INOIL.—Water in the oil is extremely harmful. Evensmall amounts soon cause pitting and corrosionof the teeth. Acid can cause even more seriousproblems. The oil must be tested frequently forwater, and periodic tests should be made for acidcontent. Immediate corrective measures must betaken when saltwater is found in the reductiongear lubricating oil system.Occasionally gross contamination of the oilby saltwater occurs when a cooler leaks or whenleaks develop in a sump. The immediate locationand sealing of the leak is not enough. Additionalsteps must be taken to remove the contaminatedoil from all steel parts. Several instances areknown when, because such treatment waspostponed—sometimes for a week or less—gears,journals, and couplings became so badly corrodedand pitted that it was necessary to remove thegears and recondition the teeth and journals.Saltwater contamination of the lubricating oil mayalso cause bearing burnout.Water, in small amounts, is always presentwithin the lubrication system as a result of con-densation. Air which enters the units containsmoisture. This moisture condenses into waterwhen it strikes a cooler surface and subsequentlymixes with the oil. The water displaces the oilfrom the metal surfaces and causes rusting. Watermixed with oil also reduces the lubricating valueof the oil itself.When the main engines are secured, the oilshould be circulated until the temperature of theoil and that of the reduction gear casing approxi-mate the engineroom temperature. While the oilis being circulated, the cooler should be operatedand the gear should be jacked continuously. Thepurifier should also be operated to renovate theoil while the oil is being circulated and after theoil circulation is stopped until water is no longerdischarged from the purifier. This procedureeliminates condensation from the interior of themain reduction gear casing and reduces rustingin the upper gear case and gears.Generally, lubricating oil will be maintainedin good condition if proper use is made of thepurifier and settling tanks. However, if thepurifier does not operate satisfactorily and doesnot have the correct water seal, it will not separatethe water from the oil. You can check for thepresence of water by taking small samples of oilin bottles, and allowing the samples to settle.These samples should be taken from a low pointin the lube oil system.Samples of lubricating oil should be tested atevery opportunity for acid, water, and sedimentcontent at a naval shipyard (or other similaractivity). With continuous use, lube oil increasesin acidity, and free fatty acids form a mineral soapwhich reacts with the oil to form an emulsion. Asthe oil emulsifies, it loses its lubricating quality.Once the oil has emulsified, the removal of waterand other impurities becomes increasingly dif-ficult. When the formation of a proper oil filmis rendered impossible, the oil must be renovated.Sometimes, when a ship from the reserve fleetis placed back in commission, the rust preventivecompound is not removed completely. The residueof this compound may cause serious emulsifica-tion of the lubricating oil. Operating withemulsified oil may result in damage to the bear-ings or the reduction gears. Since it is extremelydifficult aboard ship to destroy emulsions byheating, settling, and centrifuging, you must makesure that emulsions do not occur. At the firstindication of an emulsion, the plant should bestopped and the oil renovated.MAINTAINING FOR PROPER OILLEVEL.—It is of extreme importance that thequantity of oil in the sump be maintained withinthe prescribed maximum and minimum levels.Too much oil as well as too little oil in the sumpcan lead to trouble. If the oil level is above the4-2
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