For power generation through steam turbine or steam engine, steam is required. Steam is also required for industrial process work, hot water supply and heating installations etc. This steam is produced with the help of utility called boiler.
A boiler is a closed vessel where combustion of fuel produces heat to convert water into steam at the desired temperature and pressure.
For the safe operation of boiler, it should be inspected by various methods and at various stages. You will find some important information on boiler inspection from below description.
01) Inspection before registration:-
Every new boiler must get registration from government authority so this is the first inspection carried out on new boiler. For this inspection boiler is completely stripped off all its mountings, coverings etc. Each and every part is carefully examined for defects due to design, workmanship or transportation. If any defects found, these are noted in the registration book.
The working pressure of the boiler is fixed after testing its various parts and a certificate is issued for the results obtained. After various satisfactory tests, the boiler is registered and a registration certificate is issued.
02) Annual Inspection: -
Generally boiler inspection is carried out annually but in case of any accident or abnormal complaint it should be done at any time. In this inspection all parts, mountings and accessories are removed and inspected.
The boiler is inspected from internally and externally for any defects which may develop during the course of its working. If the boiler found defect free then only the certification of registration is renewed.
03) Hydro Test: -
The hydraulic test is carried out to inspect the tightness of joints, fittings and the leakages from the repaired parts. To carry out this test, the boiler is completely filled with pressurized water. The water pressure is different for different situations as below,
01) For an old boiler, the hydraulic pressure applied will be 150% of the prescribed pressure for operation. At the given pressure the boiler should not leak at any spot.
02) For the new boiler,
A) The hydraulic pressure applied will be 200% of the working pressure and it should not leak under this pressure. The pressure mentioned is applied when the boiler has working pressure is less than 100 lbs/inch square.
B) When the boiler is working above 100 lbs/inch square, the hydraulic pressure applied for test is 150% + 50 lbs/inch square and the boiler should not leak at any spot under this pressure.
04) Steam Test:-
To check the setting of the safety valves at the working pressure, this test is carried out. After satisfactory test, the valves are sealed and the owner is not permitted to change the settings.
05) Inspection in Presence of Steam: -
This type of test is very rare but when boiler can not stop due to any reason, this test carried out. At the time of this test, steam generation is in process by boiler. A prior approval is from government is necessary to run the boiler after expiry date of its current certificate.
06) Internal Inspection: -
When boiler is small in size and when inspector can not enter inside for close inspection of internal parts this type of test is carried out. Inspection is done when internal parts are taken out for repairs.
07) Causal Inspection:-
To check out that the boiler owner is operating the boiler according to boiler act, the surprise visits from time to time are carried out for inspection.
08) Accident Inspection: -
If due to any reason accident took place, the boiler inspector holds an inquiry to fix the reasons of accident, the damage to the boiler and worker by inspection at site.
If you know something more on the topic, please add it by comments.
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