Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
(OP)
Hello !
We are just performing a HAZOP for a Compressor Tandem dry gas seal. One question raised was regarding if the inboard (primary) and outboard (secondary) seal fails at the same time. To evaluate the risc i would be interested if this is a theoretical scenario or if someone has had this failure in reality.
Best regards
Ed16
We are just performing a HAZOP for a Compressor Tandem dry gas seal. One question raised was regarding if the inboard (primary) and outboard (secondary) seal fails at the same time. To evaluate the risc i would be interested if this is a theoretical scenario or if someone has had this failure in reality.
Best regards
Ed16





RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
good luck!
-pmover
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
We have experienced a failure of both primary and secondary seal on a gas compressor, but I suspect that the outboard seal had already failed, and we had not picked it up due to problems with our detection instrumentation.
monaco8774 we received a similar safety alert from Man Turbo - the important point is to ensure reliable detection of primary or secondary seal failure in various scenarios.
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
Failure of primary and secondary seals simultaneously can happen,due to one of the below or due to all. This can be seen in typical cases where there is no intermediate labyrinth seal between primary and secondary.
1.Defective filters. if the gas filters fail and allow large particles of dirt into the system >3 mirons.
2.Excessive axial thrust or rapid thrust bearing wear out
3.Entry of oil into secondary seal, If no barrier seals are employed and the bearing drains are choked
In the first case, Tandem dry gas seals with intermediate labyrinth seals which ensures clean N2 or air to the secondary seal, will delay the failure of sec seal. Due to failure of primary seal the high primary vent flow alarm and trip can trip the machine. such a seal failure trip will generaly close inlet and discharge valves and vent the compressor loop for safety by opening vent valve.
The seal are wonderful as long as you take all safety precautions.
Hope this will add a bit to what others said,
BVSRTT
bvsrao1949@yahoo.com
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
Special monitoring on outboard seal should be performed.
Regards;
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal
Seals without an N2 purge would have to rely upon trending of the Primary Vent pressure or flowrate to suggest an outboard seal failure. Another way might be to monitor the N2 flow rate to the bearing isolators or barrier seal. If the pressure of the primary leakage is higher than the N2 purge, the purge could be overwhelmed by the leakage and stop flowing into the barrier seal.
RE: Compressor Tandem Dry gas Seal : Failure of inboard and outboard seal