Results of theoretical analysis and testing
Finite Element Analysis and classic theoretical
calculations were also carried out to assess
the seal resistance capabilities to repeated
contact with sectorplates (Figure 4) and
cyclic loading from air/gas or gas/gas pressure
differentials (Figure 5). The conclusion of all
of this theoretical work along with the practical
test rig testing and prototype testing within
operating heaters; was that contact seals
were only suitable for closing small even gaps.
However, this is the type of leakage gap
that exists when Howden's new actuated
parabolic sectorplates are installed. This
enhanced combination provides a radical
reduction in the hot end radial leakage.
Benefits would be typically around a 20%
overall leakage reduction relative to standard
actuated sectorplates without contact seals.
In smaller package heaters, where rotor
turndown is too small to adjust sectorplates
these new Howden contact seals are
also effective.