| |
Selection of the proper refractory
material for your process equipment is
only the first step in designing a lining
which will provide an adequate service
life. Just as important is the selection
of the proper refractory anchoring system
for your lining.
Far too often, when a refractory fails,
improper anchoring can be pointed to as
the cause of the failure.
One of the most common mistakes in
anchoring is the use of an anchor made
from an alloy with a temperature service
limit less than the operating temperature
it is asked to withstand. In addition,
the presence of corrosive gasses can add
to the premature failure of anchors if
they are of the wrong alloy.
Anchor spacing is also an important
factor in the performance of a refractory
lining. Proper spacing is dependent on a
number of factors, including the type of
material to be supported, the thickness
of the lining, operating temperature, the
position of the lining, and the method of
lining installation.
Vertical linings, for example, could
theoretically stand alone with no support
if there were no external forces acting
on them. In reality, however, there are
pressures acting on most vertical walls
such as vibration, thermal expansion, and
wall loading prior to development of the
ultimate strength. Vertical walls must be
attached to the wall of the vessel to
keep it from pulling away from the
vertical position. Wall support plates
should also be used in thicker walls
every four vertical feet or so to prevent
the upper areas of the wall from applying
too much force on the lower areas of the
wall.
Once the proper anchor is selected and
the spacing is decided, the next
important step is to ensure that the
anchor is attached securely to the wall.
Proper welding techniques should be used,
including cleaning or grinding of the
steel surface.
Much like the tires on a car, refractory
anchors may not be very glamorous, but
they are an integral part of the
performance of the lining. Ask your
refractory material supplier or installer
to give you some advice on selecting the
proper anchoring system for your lining.
|
