Greetings.
We had vibration on bearing 2. The mist eliminator filter was choked so there was no sufficient vacuum for a period of time before the vibration happened. The clean side of the Air inlet filters was dirty (but not that much), also bore scope showed that the turbine buckets are dusty. Now @ the outage we have inspected the bearing 2 and found Oil leak in the bearing 2 area. Furthermore, we have opened the oil deflector and the seal ring and there was high amount of carbon in these rings. the holes on the bearing 2 casing that allow the air from BN to enter and cool was chocked with carbon.
According to GE (based on what I have understood from them). the reason for this problem is as follows
First the BN Fan takes filtered air from the inlet air and deliver that air to cool bearing 2 area. some of that air will enter through the holes in the bearing casing and then into the holes in the seal ring to cool that area. After that this air will go to the lube oil tank by the help of the vacuum created by the mist eliminator. So if you don't have clean air from the BN + no enough vacuum in the oil tank this case (carbon) would happen. this carbon if reached a certain amount, then the vibration will show up.
What we have done now is:
1- changed the filter in the mist eliminator
2- changed the inlet air filters
3- changed the oil deflector and seal ring with a new one
But still we have not run the unit.
Please can you explain this case for me in details (like how BN enters the holes and go to the tank, also why there are holes between the oil deflector and seal ring). and I don't get how the holes which air gets through got chocked. please elaborate on the issue
see the picture for the oil deflector, seal ring and the carbon
https://postimg.org/image/xhj3jd1wt/
https://postimg.org/image/t4990o10p/
https://postimg.org/image/ozys1tpf5/
Thank you
We had vibration on bearing 2. The mist eliminator filter was choked so there was no sufficient vacuum for a period of time before the vibration happened. The clean side of the Air inlet filters was dirty (but not that much), also bore scope showed that the turbine buckets are dusty. Now @ the outage we have inspected the bearing 2 and found Oil leak in the bearing 2 area. Furthermore, we have opened the oil deflector and the seal ring and there was high amount of carbon in these rings. the holes on the bearing 2 casing that allow the air from BN to enter and cool was chocked with carbon.
According to GE (based on what I have understood from them). the reason for this problem is as follows
First the BN Fan takes filtered air from the inlet air and deliver that air to cool bearing 2 area. some of that air will enter through the holes in the bearing casing and then into the holes in the seal ring to cool that area. After that this air will go to the lube oil tank by the help of the vacuum created by the mist eliminator. So if you don't have clean air from the BN + no enough vacuum in the oil tank this case (carbon) would happen. this carbon if reached a certain amount, then the vibration will show up.
What we have done now is:
1- changed the filter in the mist eliminator
2- changed the inlet air filters
3- changed the oil deflector and seal ring with a new one
But still we have not run the unit.
Please can you explain this case for me in details (like how BN enters the holes and go to the tank, also why there are holes between the oil deflector and seal ring). and I don't get how the holes which air gets through got chocked. please elaborate on the issue
see the picture for the oil deflector, seal ring and the carbon
https://postimg.org/image/xhj3jd1wt/
https://postimg.org/image/t4990o10p/
https://postimg.org/image/ozys1tpf5/
Thank you