replacement of agitators , rakers and clarifloculators in pa / pc plants , fact cd . , replacement of agitators , rakers and clarifloculators in pa / pc plants , fact cd . , maintenance and replacement of agitators . work involves: a ) decoupling drive motor , removing from position , transporting to electrical work shop or any other place as per the instruction of engineer in-charge , collect repaired / new motor , transport to site , fixing , alignment and coupling . b ) decoupling gearbox from agitator , transporting to mech workshop or any other place as per the instruction of engineer- in-charge , removal of coupling from gear box and re fixing ( if required ) transport back to site , fixing , alignment and coupling . c ) lifting and transporting the defective agitator from pit / attack tank , cleaning thoroughly for inspection , minor repair like welding of cracks , straightening and reinforcing , welding of bend blades , replace worn out parts like blade , stiffeners , gland , coupling , bearing housing etc . by welding and building up , transporting to and back from workshop for machining and after machining , assembling with new bearing ( if fitted with bearings ) and making ready for use . d ) minor repair of foundation of agitator , motor , gearbox and base plate by replacing damaged structural members / repairing the weld cracks etc . as per instruction of engineer- in-charge . e ) fixing back the repaired / new agitator in position , leveling , tightening and servicing without any defect . the above works are to be arranged on the following equipments . a ) digestion vessel agitators . i / ii / iii . b ) attack tank agitators of 11 , 12 , 13 , 14 , 15 , 16 compartments , weak and strong acid storage tank agitators . c ) 21st compartment agitator , slurry circulators , agitators of fst and pumping vessel agitators . d ) 30% and 45% settler rakers , clarifloculators in p . c . plant .