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Power Plant Engineering 2.17 High Pressure Boilers, , , , Provisions under Boiler Act for Remedial Measure:, 1. Prohibitions of use of unregistered or uncertified boiler., 2. Renewal of certificate from time to time., 3. Modification and Renewal to boiler., 4. Modification or changes in steam pipes., , , , 2.15 MAINTENANCE PROCEDURE FOR MAJOR COMPONENTS OF, HIGH PRESSURE AND FBC BOILERS, ¢ Maintenance of high pressure and FBC boilers can be done in two stages:, (A) Boiler inspection:, ¢ The boilers are required to be tested regularly as per Indian Boilers Act. Before inspection, boiler, should be made empty and all manhole doors, caps, mud drums, fire bars, front end bridge plates,, oil burners etc. should be removed and boiler should be cleaned., ¢ All tubes, smoke boxes and external flues should be cleaned and checked., ¢ All the steam and water connections should be disconnected and then, it should be made ready for, conducting the following tests:, , (a) Hydraulic Test: This test is conducted to find out leakages in steam boiler. For this test, the, mountings should be fitted tightly except the safety valves. The openings of the safety valves, should be closed. All the joints should be made tight and leakproof. Boiler should be filled with, water and inspector's gauges should be fitted to the boiler. Generally, the boilers are tested at a, pressure equal to twice the working pressure of the boiler. During this test, no part of boiler, should deflect., , (b) Steam Test: This test is conducted to check whether the safety valves operate properly to relieve, the steam, when the steam pressure inside the boiler exceeds the rated pressure. This operation, is tested keeping the feed valve and steam stop valve closed., , (B) Boiler Maintenance:, e Regular maintenance and careful supervision of working of various components of boiler result in, the efficient operation of the boiler., ¢ The various factors, which should be carefully observed for proper maintenance of the boiler are as, follow:, , 1. The combustion equipment should be so adjusted that, the temperature in the furnace does not, exceed the designed value. The air supply to the furnace should be in correct proportion., , 2. The water level in the boiler should not be allowed to fall beyond the minimum level., , 3. The temperature should change slowly and uniformly in the various parts of the boiler. Rapid, changes in temperature lead to unequal expansion., , 4. The water used for steam generation should be free from scale forming impurities, because the, scale deposited on tube and boiler shell does not allow the heat transfer to take place effectively, and sometimes causes over heating of tubes and boiler shell, which may result in failure of tubes, and boiler explosion., , 5. Soot and ash deposited in tubes on gas side should be removed regularly., , Bearings of pumps, stokers, pulverisers and fans etc., should be lubricated regularly., , 7. Oil or scale in the tubes is undesirable. Hence, such tubes should be traced or located to solve, the problem., , 8. All stays should be in even tension and they should be properly adjusted., , 9. The tube leakage is caused due to extreme overheating of tubes as it is exposed to high, temperature. The boiler should be stopped, when such leakage is noted and it must be, immediately repaired.