Siemens Halo seal
For as long as turbo machinery has been built there has been an ongoing search for better seals. Internally to rotating equipment where there is a rotating element and a stationary component there will be a seal. On centrifugal compressors the internal seals are located at the impeller-eye, inter stage, end-seal, balance piston and division wall locations (pictured) and are typically aluminum labyrinth seals. These seals leak gas that recirculates back through the impellers and get recompressed. This is a waste of power. The more recirculation the less through put the compressor can produce. Many types of seals have been designed, many materials have been developed and a myriad of options exist on the market today. Categorically, the traditional seals available eventually contact the rotating element, wear, and recirculation increases over time until it is so bad that the unit must be overhauled with new seals. Operators are in constant search for ways to lengthen this cycle. Introducing Halo™: The most advanced seal available for internal seal locations.