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JSW ENERGY BOLT | ISSUE 2
Vijaynagar
Innovative Idea Of Providing Air Curtain At Turbine
Bearing And Bulb Seals In PA And ID Fan
In 300 MW Unit
How and Why was the problem Passing of dampers was resulting in
identified? increase in down time of the equipment
affecting unit availability.
1. Air curtain for Turbine Bearing Pedestal
Oil Catchers: Apart from the above observation, safety
It was noticed that gradual deterioration of was the major concern to take into
oil properties was alarming. On detailed consideration for executing maintenance
analysis, it was summarised that the activities.
change in properties was due to huge
How was the problem solved?
ingression of duct and metallic
ingredients. Owing to dusty environment, 1. Air curtain model prepared for all bearing
chances of iron and coke dust entry into pedestal oil catchers to feed fresh air
the system is inevitable. continuously by avoiding dusty air into
bearing chamber.
As the Turbine oil system operates in a
closed loop with a negative pressure in the 2. Existing Hast alloy seals installed on
bearing chamber, dust entry into the damper flap were not giving complete
system is bound to occur resulting in oil sealing between flaps as its thickness
contamination and subsequent damages was very less. Hast Alloy seals were
to the bearing. replaced with bulb seals which have
additional stiffener to exert seal pressure
2. Passing of PA fan and ID fan dampers:
on other seal. Modification of seals was
PA fans and ID fans are the critical
carried out in PA fan discharge dampers
equipment to maintain PLF of any unit. As
and ID fan IGVs. Bulb seal provided
these fans are equipped with dampers
between flap gives complete seal
supplied by OEM was leading to heavy
between flap to flap.
passing during fan outage resulting in
reverse rotation of fan when isolated.
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