Non-Contacting Face Seal Application: Gearbox

The Gearbox in a commercial aircraft engine had multiple locations with carbon face seals experiencing high leakage and seal failures. Technetics’ Qualiseal® Technology was called upon to find a solution to reduce time and expense due to maintenance downtime.

Operating Conditions

  • High speed (up to 27,000 rpm)
  • Gearbox oil (MIL-R-23699)
  • 5 psid

Determining Cause and Failure Modes

  • High heat generation of seals caused oil to coke
  • Abrasive coke particles became embedded in sealing faces causing excessive leakage and wear
  • Seals had to be replaced on the wing before scheduled maintenance of the gearbox due to excessive leakage

Technetics’ Qualiseal® Technology Solution

  • Designed a new non-contacting carbon face seal with hydrodynamic features on the mating ring to reduce heat generation
  • The new design allows for maintenance-free seals before the gearbox is pulled for scheduled maintenance
  • Final design solution required NO COST INCREASE over the original product

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