Brush Seals

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Brush Seals

Technetics Group Brush Seals - Designed to increase airflow efficiency in engines and compressors

Replacing labyrinth seals with brush seals from Technetics Group can reduce leakage by 5 to 17 times, thus providing significant turbomachinery efficiency and output gains.

Brush seals work by absorbing the radial deflections between the shaft and rotor during transient operation. The seal then follows the rotor back to the steady state operating position to maintain minimum leakage. The brush pack is composed of thousands of finely packed 70 to 150 micron diameter wire bristles. The bristle material, a cobalt or nickel alloy, is selected to provide an optimal combination of wear properties and oxidation resistance. The backplates and sideplates are typically fabricated from stainless steel or nickel alloys. The primary consideration is thermal expansion and contraction of the case material.

Technetics Group can manufacture brush seals from 2 inches to 110 inches in diameter. Brush seals can be delivered as a single unit or in multiple segments. The bristles can be configured radially inward, radially outward or axially.

To learn more about Technetics Group Brush Seals, download our Brush Seals PDF. You can also contact us for a custom-engineered solution to your application or to request a quote.

 

Pressure balancing

Pressure balanced design technologies, licensed through Rolls Royce, reduce the force required to deflect the bristles and prevent bristle pack “hang up” following a radial excursion.

In a standard brush seal design, the pressure drop across the bristle pack increasingly loads the bristles against the back plate. This effect creates frictional forces that must be overcome when the rotor deflects the bristle pack radially. Additionally, once the rotor moves back to the steady-state position, these frictional forces will prevent the bristles from tracking with the rotor and create an annular clearance and increase seal leakage.

The pressure-balanced design incorporates a pressure relief cavity along the downstream face of the bristle pack. The cavity is a high-pressure pocket that offsets, or balances, the distributed load on the upstream face. The result is a brush that moves freely with the rotor with no hysteresis.

Advantages

  • Reduced wear rate means longer life
  • Consistent flow provides predictable performance
  • Higher-pressure operation yields flexibility in design
  • Reduced heat generation ensures a cooler rotor
 

 

Resources

APPLICATION DATA SHEET- BRUSH SEALS APPLICATION DATA SHEET- BRUSH SEALS Complete Form
BRUSH SEALS BRUSH SEALS View/Download