Chapter 12- PROPULSION STEAM TURBINES 



Preventive inspection and maintenance are 

 vital to successful casualty control, since these 

 activities minimize the occurrence of casualties 

 by material failures. Continuous and detailed 

 inspection procedures are necessary not only 

 to discover partly damaged parts which may 

 fail at a critical time, but also to eliminate the 

 underlying conditions which lead to early failure 

 (maladjustment, improper lubrication, cor- 

 rosion, erosion, and other enemies of machinery 

 reliability). Particular and continuous attention 

 must be paid to the following symptoms of mal- 

 functioning: 



1. Unusual noises. 



2. Vibrations. 



3. Abnormal temperatures. 



4. Abnormal pressures. 



5. Abnormal operating speeds. 



Operating personnel should thoroughly famil- 

 iarize themselves with the specific tempera- 

 tures, pressures, and operating speeds of equip- 

 ment required for normal operation, in order 

 that departures from normal operation will be 

 more readily apparent. 



If a gage, or other instrument for recording 

 operation conditions of machinery, gives an 

 abnormal reading, the cause must be fully in- 

 vestigated. The installation of a spare instru- 

 ment, or a calibration test, will quickly indicate 

 whether the abnormal reading is due to instru- 

 ment error. Any other cause msut be traced to 

 its source. 



Because of the safety factor commonly in- 

 corporated in pumps and similar equipment, 

 considerable loss of capacity can occur before 

 any external evidence, is readily apparent. 

 Changes in the operating speeds from normal 

 for the existing load in the case of pressure- 

 governor-controlled equipment should be viewed 

 with suspicion. Variations from normal pres- 

 sures, lubricating oil temperatures, and system 

 pressures are indicative of either inefficient op- 

 eration or poor condition of machinery. 



In cases where a material failure occurs in 

 any unit, a prompt inspection should be made of 

 all similar units to determine if there is any 

 danger that a similar failure might occur. 

 Prompt inspection may eliminate a wave of re- 

 peated casualties. 



Abnormal wear, fatigue, erosion, or corro- 

 sion of a particular part may be indicative of a 

 failure to operate the equipment within its de- 

 signed limits or loading, velocity and lubrication, 



or it may indicate a design or material de- 

 ficiency. Unless corrective action can be taken 

 which will ensure that such failures will not 

 occur, special inspections to detect damage 

 should be undertaken as a routine matter. 



Strict attention must be paid to the proper 

 lubrication of all equipment, and this includes 

 frequent inspection and sampling to determine 

 that the correct quantity of the proper lubricant 

 is in the unit. It is good practice to make a daily 

 check of samples of lubricating oil in all aux- 

 ilaries. Such samples should be allowed to 

 stand long enough for any water to settle. Where 

 auxiliaries have been idle for several hours, 

 particularly overnight, a sufficient sample to 

 remove all settled water should bedrainedfrom 

 the lowest part of the oil sump. Replenishment 

 with fresh oil to the normal level should be in- 

 cluded in this routine. 



The presence of salt water in the oil can be 

 detected by drawing off the settled water by 

 means of a pipette and by running a standard 

 chloride test. A sample of sufficient size for 

 test purposes can be obtained by adding dis- 

 tilled water to the oil sample, shaking vig- 

 orously, and then allowing the water to settle 

 before draining off the test sample. Because of 

 its corrosive effects, salt water in the lubricating 

 oil is far more dangerous to a unit than is an 

 equal quantity of fresh water. Salt water is par- 

 ticularly harmful to units containing oil- 

 lubricated ball bearings. 



An an example, the maintenance require- 

 ments which shall be conducted in accordance 

 with the 3-M System is shown in figure 12-30, 

 (Maintenance Index Page). 



CASUALTY CONTROL 



The mission of engineering casualty control 

 is to maintain all engineering services in a state 

 of maximum reliability, under all conditions. To 

 carry out this mission, it is necessary for the 

 personnel concerned to know the action nec- 

 essary to prevent, minimize, and correct the 

 effects of operational and battle casualties on 

 the machinery and the electrical and piping 

 installations of their ship. The prime objective 

 of casualty control is to maintain a ship as a 

 whole in such a condition that it will function 

 effectively as a fighting unit. This requires ef- 

 fective maintenance of propulsion machinery, 

 electrical systems, interior and exterior com- 

 munications, fire control, electronic services, 

 ship control, firemain supply, and miscellaneous 



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