Seal failure index

2.0 Oil barrier seals

Oil barrier seal index

2.3 Failure due to loss of clearance

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	Figure 2.3a Failure of seal ring through deposit of ammonium succinate formed by reaction between ammonia in the gas and the corrosion inhibitor in the oil.     Figure 2.3b Electrostatic erosion of white metal lining of seal ring causing increased inward leakage of the seal oil
Main Characteristics	Failures can occur through loss of clearance caused by deposition of reaction products between the process gas and additives in the oil. Figure 2.3a shows a failure of a seal ring caused by reaction between ammonia in the gas and the succinic acid corrosion inhibitor in the oil. The ammonium succinate reaction product is insoluble in the oil and is deposited on the hot lining of the seal ring. Rings with low clearance are used to limit the inward leakage of the barrier oil. This results in a low oil film thickness between the rotor and the casing and this is the most likely place for discharge to occur in the event of electrostatic build up on the rotor. Figure 2.3b shows electrostatic erosion of the white metal lining of a seal ring giving increased clearance and excessive inward leakage.
Cause
Note
Possible Confusion with Other Types of Damage
Comment

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