Page 22 - GarlockFluidSealing2010

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Construction
Figure 1
Figure 2
Figure 3
Compression packings are made in a variety of
shapes, sizes and constructions, from a wide range of
materials. The following describes the most commonly-
used constructions, and the advantages of each.
Braid-Over-Braid (Figure 1)
Round braiding machines braid tubular jackets
using yarns, rovings, ribbons and various other materi-
als, either alone or in combination. Size is obtained by
braiding jackets one over the other (braid-over-braid).
Finished packings can be supplied in round, square or
rectangular cross section. Braid-over-braid packings,
also known as round braid or multiple braid packings,
are relatively dense and are recommended for high-
pressure, slow-speed applications such as valve stems,
expansion joints, groove gasketing, etc.
Braid-Over-Core (Figure 2)
Finished product is produced by round braiding
one or more jackets of yarns, rovings, ribbons or other
forms of various materials over a core, which may be
extruded, twisted, wrapped or knitted. This construction
allows for a wide range of densities and different cross
sectional shapes.
Square Braid (Figure 3)
Yarns, rovings, ribbons and other various materi-
als, either alone or in combination, are processed on
equip-ment where strands pass over and under strands
running in the same direction. Resulting packings are
usually supplied in square cross section, but rectan-
gular sizes can also be braided by this method. The
packing is usually soft and can carry a large percent-
age of lubricant. Square braided packings are easy on
equipment and are generally used for high-speed rotary
service at relatively low pressure. The packing’s soft-
ness makes it ideal for old or worn equipment.
LATTICE BRAID® (Figure 4)
Yarns, rovings, ribbons and other forms of various
materials, either alone or in combination, are processed
on equipment where the strands crisscross from the
surface diagonally through the body of the packing.
Each strand is strongly locked by other strands to form
a solid integral structure that cannot easily ravel or
come apart in service. There are no jackets to wear
through, and no plaits to come loose. LATTICE BRAID®
packing has a more even distribution of yarn density
throughout and has the potential for improved lubricant
retention. The fnished packing is relatively dense, but
fexible.
LATTICE BRAID® packings are suitable for appli-
cations on both reciprocating and centrifugal pumps,
agitators, valves, expansion joints and in grooves.
Figure 4