SEALS AND SEALING ELEMENTS
Labyrinth seals
A special form of dynamic sealing is the so-called labyrinth seal. It is used to seal elements (shafts etc.) rotating at high speed. In these applications additional high pressures and/or temperatures often occur, e.g. in turbines.
Due to the high mechanical and thermal loads, metallic materials are often used for labyrinth seals. However, high-performance plastics offer significant advantages within certain temperature limits and are superior even to metallic materials.
Labyrinth seals made of the materials listed below have proved particularly effective:
By using high-performance plastics instead of metallic materials, significantly higher sealing performance can be achieved. Depending on the application, the efficiency per sealing stage can be increased by 0.5 to 2% with labyrinth seals made of high-performance plastics.
The lower leakage rates can be achieved because the high performance plastics allow significantly smaller gap dimensions. Due to the good toughness and high wear resistance, neither the seal nor the shaft are damaged on contact, unlike with metallic seals. Also, due to the good dry-running properties of the high-performance plastics, it is generally impossible to work in (seize) the seal and counterpart.
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