 Since
the dramatic economical development, mechanical seals have been
increasingly used for sealing rotating shafts. Today, they are
the predominant type of seal found on centrifugal pumps, compressors,
and similar machines. In terms of sealing efficiency and versatility
of application, they represent a significant improvement over
former sealing techniques, for example, gland packing, which
they have now largely displaced. 
Mechanical seals are the most versatile
type of seal for rotating shafts. Their main use is on liquid/gas
sealing, e,g.,centrifugal pumps. Mechanical seals are also used
on gas/gas applications, e.g., compressor and agitator shaft
seals, but in these cases they are usually deployed as double
seals with liquid injection to provide lubrication of the seal
faces. Liquid/liquid sealing duties occur in such applications
as double seals where process fluid is on one side and barrier
fluid on the other. Mechanical seals have largely replaced soft-packed
glands because of low leakage and the absence of a requirement
for routine maintenance. |
