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[PRODUCTS]
Thin-wall
Metallic Expansion Joint: Universal
The universal expansion joint
consists of two bellows separated by a pipe section or spool. The
primary purpose of this arrangement is to have a unit which will accept
large amounts of lateral deflection. The amount of lateral deflection
they can accept is a function of the amount of angulation each bellows
can absorb and the distance between the bellows. For a given bellows
element, the amount of lateral deflection capability can be increased or
decreased by simply changing the length of the center spool. In this
catalog three standard overall lengths are given with their lateral
movement capability. If the piping problem requires greater capability,
then the overall length can be increased to suit.
Since deflections are usually the
result of piping thermal expansion, and universal expansion joints are
usually long, our units are designed so that the thermal expansion of
the entire unit's length is accepted as compression by the two bellows
elements. In this way, the overall length of the unit does not change
when the piping is heated. The standard units in this catalog have all
been designed to accept the thermal expansion of their length when the
temperature is up to the design temperature shown.
Universal types can be supplied
with or without tie rods. Tie rods connect the ends of the unit to each
other and restrain the pressure thrust load. This unit is normally not
expected to accept any externally applied axial deflections. The thermal
expansion of the distance between the tie rods ---within the expansion
joint--- will be handled by the bellows element, as described above. The
tie rods usually come in sets of two or more, equally distributed around
the circumference of the expansion joint. When only two are provided,
180 degrees apart, the expansion joint is free to bend, or deflect
angularly, as well as laterally. With three or more tie rods, since rods
are loaded equally by the pressure thrust, only lateral deflections are
possible without significant forces being applied by the adjacent
piping. Without tie rods, the universal expansion joint will accept all
of the deflections that a single type will, and the pipe guiding and
anchoring needs discussed for the single type above also apply.
Many times the universal expansion joints will
be attached directly to pipe elbows as shown on page 12. As discussed in
more detail in the Applications Section, this arrangement, because of
the large lateral deflection capability, accepts the thermal expansion
of relatively long runs of heated pipe. So that the distance between the
elbows does not change due to thermal expansion, the tie rods can be
connected to the elbows themselves. This catalog offers this type of
arrangement as one of the standards, and can be seen on each of the
Universal expansion joint pages, along with their dimensions and
performance characteristics.
Metalic Expansion Joints
Fabric Expansion Joints
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