Brush seals are composed of thousands of fine wires and are used to form barriers against flying debris and liquid, block the infiltration of light or air, and seal gaps in doorways. They are available in many shapes and sizes and made from a variety of materials. Brush seals are useful in turbines and aerospace applications because they can form effective barriers while also allowing for thermal or mechanical movement. They are used in high temperature applications to reduce heat loss and in acoustic applications to reduce sound transfer. Brush seals are also used in hollow doors, double hollow metal doors, dock levelers, double doors, doors, rolling steel doors, sectional overhead doors, and windows.
Brush seals are available in nylon or polypropylene filaments or can be made with natural fibers such as horsehair. They can also be made of nickel-alloy bristles to withstand high-temperature applications. The mounting channel for a brush seal is typically made of extruded aluminum and can be configured to fit various widths. Brush seals are flexible, allowing them to conform to any surface to form an effective seal. Brush seals can conform around moving parts with minimal friction. This makes them useful in turbine and aerospace applications.
Aerospace brush seals are air-to-air seals composed of thousands of densely-packed wire filaments fused between two metal plates and are used in jet engines and turbines. Aerospace brush seals are designed to come in contact with the jet engine rotor to provide a positive seal. Because of the flexibility of the wire filaments, brush seals are more effective than traditional labyrinth seals which do not come into contact with the rotor. The flexibility of the hair-like wires enables the brush seal to adjust to changes in the rotor, including start-up, shutdown, and to vibrations during normal operation. Brush seals that are UL-listed meet published standards of safety from Underwriters Laboratories (UL), a third-party certification organization.