heavy-duty channelseal handles higher pressuresbut doesn’t have much travel.
It features a top surface and
base that are reinforced to
hold their shapes. But its side-
walls are not reinforced, let-
ting them stretch when the channel
seal handlesheavy-duty applications and
mounts in a groove or metal
channel that supports its sides
and helps keep it in place. It
may be held in place by adhe-
sives or simply by friction with
the sidewalls. These
seals are
widely used as grippers on ro-
bots and in part fixtures and
handling.The heavy-duty snap
seal handles higher pressures and
is more durable than standard
footed snap
seals. But it deliv-
ers less travel and has no foot
to act as a mounting point. In-
stead, it is held in place with
adhesives. This
seal is widely
found on food and pharmaceu-
tical-processing equipment be-
cause its straight sides make it
easy to clean and it has no
crevices to trap debris.The footed snap
seal deliv-ers relatively large travel for
its width, so it can close big
gaps, but this comes at the ex-
pense of durability and pres-
sure capacity. When deflated,
the
seal collapses into itself.
And if it is inflated beyond acertain point, it snaps into a
round cross section. The con-
tact surface is made extra
thick to withstand wear.The footless
seal deliversthe same performance as the
footed
seal, but is held in place
by friction. It is often used in
tight spaces where there’s no
room for a footed
seal, or
geometry of mating parts can
be used to keep it in place. A
footless
seal should not be
glued in place because the
base doesn’t remain flat after
inflating the
seal.The
Designing With Inflatable Seals - 7327 FASTENING & JOINING
footed
seal is the mostwidely used. It can be fastened
in place using the foot, while
its wall provides a good combi-
nation of durability, pressurecapacity, and range of travel.
There are usually used around
doors and hatches.The
Custom in-flatable
seals
can be provided
in a wide variety
of configurations,
including rectangular,
U-shaped, and wind tun-
nel. They generally cost less
and
seal better than compres-
sion
seals, especially on rough and
irregular surfaces.
Round
inflatable seals can act axially,inward radially, or outward radially.
CROSS SECTIONS
Inflatable
seals come in awide variety of shapes or cross
sections. But engineers can
meet most design needs with
one of six basic designs. All
seals can expand in whatever
direction is needed. The main
issues regarding cross-section
selection are required pres-
sures and amount of travel. In
some applications, cleanliness
is also a consideration. For in-
stance, some cross sections
have fewer crevices to trap
contaminants and are easier to
clean. In fact, they were devel-
oped mainly for food and phar-
maceutical industries.The
Axial expansionExpand in
Expand out
