Combination beading Expanders for fire tube boilers
combination beading expander series - boiler tube expanders
Configuration: four Parallel rollers with one beading roller
Tube sizes covered: 2.0", 2.1/2 and 3.0" OD.
features:
Rolls and beads in one operation.
No need for beading tools or air hammer.
No operator fatigue caused by continuous use of air hammers.
No need to re-roll after completion as with manual beading.
Use:
The Combination Beading Expander comes in three sizes, 2.0", 2.1/2" and 3.0" OD.
NOTE: You only need to replace the Beading Roll and the Guide Roll assembly to change tube wall thickness.
The Powermaster Industrial Combination Beading Expander is is a leader in saving time and reducing operator fatigue. The quality of the bead is consistent around the tube edge with no ridges as in air beaded tubes which can cause cracking on the bead by over working it. As seen below:
The above images are of 2.1/2" 11 BWG tubes we rolled with a total of 104 tube ends. The whole installation was completed in one day including hydro test. The rolling motor used had the capacity for 3.0" tubes. W can't stress enough the key to this operation is proper lubrication to conquer the inherent heat build up from friction within the tool. As a lubricant we used our own Lube Right developed here in Canada for the expansion of tubes.
Theory of The Combination Beading Expander
The combination beading
and expanding tool
simultaneously expands and beads the
tube end in a single operation.
Operating as it does, the tool
assures the creations of a joint,
which is both pressure tight and has
a bead in intimate contact with the
tube sheet. The tool achieves this
objective by the natural feed force
built in to the expander to force
beading against the end of the tube
while expansion is taking place. The
ability of the tool to
satisfactorily accomplish this
depends upon the amount of tractive
force available being of enough
magnitude to enable feeding forces
to be developed which will enable
the beading roll to deform the end
of the tube and press the bead
tightly against the sheet. The
tractive force is made a maximum by
utilizing five expansion rolls in
place of the three or four normally
found in expanders of this type and
using coolant, which has the quality
of minimum lubricity. If the beading
roller expander is set so full
expansion is accomplished before the
bead has been formed, it will not be
possible to complete a proper bead
without further expansion of the
tube.
The tool operates such
that, once the beading roll has
encountered the end of the tube, the
entire inward force of the tool is
available to form the bead. However,
this force is not always of
sufficient magnitude to perform the
required operation. The force is at
a minimum initially while the
expander is expanding the tube to a
metal to metal condition. At this
point the tractive force increases
sharply and builds to a maximum as
the expansion progress. When the
stop nut on the mandrel engages the
thrust bearing on the cage housing
preventing any of the mandrel. This
force then diminishes as continued
rotation of the expander irons out
the tube bead. Therefore, it is
necessary that the beading operation
be completed before the final
expansion of the tube since it will
require the maximum tractive force
available to perform the beading.
Because of normal manufacturing
practices, it would be possible to
perform a proper beading and
expanding operation with the tool
without necessary setting it so that
the beading roll was in contact with
the end of the tube. How far back
would be determined by two factors,
one would be the amount of clearance
between the tube sheet hole and the
tube OD. The greater this clearance,
the further back the beading roll
could be set since effective
tractive force will not be developed
until the tube has been expanded to
the metal to metal condition. The
second factor would be to set the
tool with the beading close to or in
contact with the tube end. It must
be emphasized that no expanding tool
can do a satisfactory job unless the
following three items are complied
with:
- 1. Tool of the correct size
- 2. Tube ends and tube sheet holes have been properly prepared and are clean.
- 3. The tool is properly lubricated.
Compliance with these requirements is even more of a critical nature when using the Combination Beading Expander.
