Brg#2 Vent and its high noise level - GT fr.9 E


Thread Starter


Why GT Fr. 9E bearing no. 2 vent line is to noisy. Does it help in any kind on condition monitoring of bearing seals condition ?

Does Brush seals instead of conventional labyrinth actually produces less noise ( as we observed in comparison of two machines) ?

finally, can we put silencer in the vent line and how much back pressure is allowed ?
When did this problem start?

There is a considerable amount of cooling and sealing air supplied to the #2 bearing (which is "inside" the unit). If the #2 Bearing Vent (sometimes called the "fire plug") is not installed properly or there is some problem with excessive cooling and sealing air flows into the #2 bearing then the noise can be excessive.

I would not recommend installing any kind of silencer or flow restriction on the vent outlet without consulting the packager of the turbine and without attempting to understand why there is excessive noise or excessive air flow out of the vent. You may cause other problems by trying to reduce the noise, and those other problems could be expensive to rectify for a little "peace and quiet".

If the problem was exacerbated or began after a maintenance outage, then it's a good bet that something was amiss with the reassembly of the unit. There have also been problems with cooling and sealing orifices not being the proper dimensions or not being reinstalled in the proper locations.

Please consult with the packager of the unit for resolution to this problem. If this is a newer unit which is still under warranty, then this is definitely something which the packager should be reviewing and helping to explain or rectify. But taking unilateral action to reduce the noise could cause unintended problems.

And, everyone's definition of excessive noise is different. If the unit has a noise level guarantee and it's relatively new, then this should again be discussed with the packager in view of the noise guarantee.

Any difference between seals as it affects #2 bearing vent noise levels should also be discussed with the packager.