1.
AXIAL MOTION:
Axial motion means dimensional variation of a flexible
tube along its longitudinal axis and displacement is
expressed as the amount of extension/contraction or percentage
of them for primary length. Braided Hoses should not
be used for such motion.
Unbraided corrugated Hose is recommended while care must
be taken in limited length by buckling. For axial displacement,
an expansion joint is more suitable.
2. PERMANENT BEND: In order to simplify the connection of two piping systems,
it is used in place of an ordinary bend pipe. If the
Hose is bent and installed in excess of the minimum allowable
bend radius of the tube, motion of the piping system
will be absorbed to a certain extent by the tube.
3 OFFSET MOTION: Offset motion is the parallel motion that occurs in a
tube with a flange at both ends while the distance between
the two flanges remain the same. The amount of the motion
is the movement of center line of free end up and won
from the center line of the fixed end. It is expressed
as plus and minus M respectively or as total motion T.
When a corrugated Hose is used for vibration, offset
is considered small and can be regarded as L=C. When
offset is large as with thermal expansion etc., the difference
between L and C is considerable, care must be taken when
installing.
4. RADIAL MOTION: When a Hose is bent and attached, as shown in figure,
radical motion is the horizontal or vertical motion at
the beginning of the circular arc. It is generally called
a moving loop and the amount of motion is expressed as
the horizontal or vertical distance moved.
If a total motion is known and bend radius is properly
chosen, the actual length of the tube and loop length
can be calculated.
5. RANDOM MOTION: Besides the above four types of motion, there is disordered
one called random motion. A garden Hose is a typical
example. Even when a Hose is freely handled, it will
suffer random movement.
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