arches are a very economical means of constructing a
kiln or furnace roof. Their use is widespread in many
industries. A thorough understanding of proper design
and installation practice is necessary to ensure maximum
life of the lining.
A general rule
worth following is to limit the use of the suspended
roof design to applications where the temperature will
not exceed 1345°C (2450°F). Above this
temperature, the better solution is to utilize a sprung
arch construction. IFB exposed to higher
temperatures is limited in its ability to resist forces
of traction. This applies to even the highest IFB
applications in the ceramic industry can be filled by
BNZ 26-60 IFB. It is a specially formulated brick
with a high alumina content that is very stable, shock
resistant, alkali attack resistant, and has a very low
temperature furnace roofs, BNZ 23 HS is equally good.
ceramic hanger overcomes the two primary shortcomings of
normal stainless steel hangers.
• Ceramic hangers withstand temperatures up to 1300°C—
nearly 400°C higher than the limit of stainless steel.
The traditional stainless steel hanger is embedded
approximately 50 mm from the cold face of a module. Care
must be exercised during design to ensure that the
maximum temperature limit of the anchor is not exceeded.
Module failure can occur, resulting in premature
shutdown of the furnace.
• Ceramic hangers
resist chemical attack better than stainless steel
hangers. Chemical attack can occur in a ceramic
kiln when corrosive elements condense out of gasses that
have penetrated the IFB modules in positive pressure
zones. The path of these gasses is most often through
the gaps that exist between mortared blocks. As stated
previously, this is not a problem with BB-Blok because
of the precision machining.
Roof thickness is
a function of two design criteria that oppose one
another in the old style modules: energy conservation;
and the physical limitations of the steel hangers as
for energy efficiency necessitates thick layers of
backup insulation, causing the hangers to be subjected
to temperatures above safe limits. The solution is to
sacrifice energy efficiency to protect the hangers, or
to specify thicker brick modules. Thicker IFB
effectively move the anchor tip away from the hot face,
but drives up the cost of the modules.
By specifying the
new BB-Blok with a ceramic hanger, additional insulation
can safely be installed without worry of anchor