FIELD OF THE INVENTION
The present invention relates to an improved configuration of the anchor system for
retaining the cast monolithic refractory lining and method of installation for the same on
shell roof and/or walls used in ladles, tundishes, roof of the ignition hearth furnace of
Sinter plant, rotary kiln and the like, so as to enhance the life of the refractory avoiding
cracking due to dissimilar thermal expansion of the shell metal and the lining material and
thereby accumulation of stress during furnace operation. The configuration of the anchor
systems according to the present invention are broadly divided into two parts viz. (i) the
Anchor Support & (ii) the Anchor proper, both made of stainless steel. The anchor proper
is further divided into two types viz. (i) the Conjugate Anchors and (ii) Linear pair Anchors.
Conjugate anchors are further comprising two Y-types of anchors made of 8-16mm
diameter Stainless Steel rod depending upon the thickness of monolithic lining, that are
complementary to each other, always used in pairs preferably for roof lining of industrial
furnaces and are separated by a selective distance based on lining thickness. The linear
pair anchors on the other hand are combination of L-type and Y-type anchors, the two
being joined flexibly and linearly. Design configuration of the anchor support is such that
the base of the anchor proper can fit properly onto it and anchor hangs freely after
installation. There is free movement of anchor proper inside the anchor support in the
installation arrangement. The anchor support is properly welded to the furnace/kiln shell.
These anchor supports are made out of 6-10 mm thick stainless steel plates depending on
the size of anchor proper and lining thickness. The configuration of anchor system
according to the invention and the installation arrangement thereof thus provide flexible
connection in between the shell wall and the monolithic castable lining and thus ensuring
stress free operation of the refractory lining while the furnace is operating at high
temperatures and the consequent development of thermal stress developed in the shell
wall or the induced stress on adjacent monolithic refractory lining leading to generation
and propagation of cracks. The hot gases of refractory are also prevented to further heat
up the metallic shell wall in absence of cracks/gaps in lining and thus eliminating
consequential damage of shell wall such as buckling/bulging. The anchor design and
installation according to the present invention is thus capable of providing longer life of the
monolithic refractory lining of furnace roof/wall and thus avoiding frequent breakdown and
loss of production, avoiding incurring associated costs and improving productivity of
furnaces/kilns and hence capable of wide industrial application with significant economic
advantage.

BACKGROUND ART
It is well known in the field of refractory lining for industrial furnaces and kilns that the
technical developments in the use of monolithic refractories have risen dramatically over
the last 20 years in India. While the major attention was on the castable compositions of
monolithic refractory to improve physical, chemical and thermal properties, the importance
of Anchor designs and their installation techniques drew little attention for further
development to avoid damage/crack of lining due to accumulation of thermal stresses and
related downtime and costs. Most of the failures in monolithic linings occur due to
inappropriate anchor systems. Costs involved in remedial measures and downtime due to
failure of refractory structures are enormous. Proper design configuration, selection of
materials and installation methods are important considerations to achieve desired
characteristics, longevity and performance of monolithic refractory after installation in
furnaces/kilns.
Conventionally, during installation of monolithic refractory, either V- or Y- Type anchors
are used depending on the lining thickness of monolithic refractory. Generally V-type
anchors are preferred for small thickness (<150 mm) and Y-type anchors are used for
higher thickness (>150mm). Also at the time of installation of the monolithic refractory,
base of the anchors is welded to the furnace shell or kiln. For example, such anchors are
used in ladles, tundishes, roof of the ignition hearth furnace of Sinter plant, rotary kiln,
etc. Since the coefficient of thermal expansion of the refractory material and the metallic
shell are quite different, such type of anchor installation causes undesirably high stress in
the monolithic structure as well as in the furnace shell. This undesirable development of
stresses cause cracks in the monolithic structure. Once cracks develop in the lining, hot
gases inside the furnace/kiln enter the cracks and reaches near to the furnace shell
causing the increase in shell temperature. Increase in shell temperature causes further
increase in undesirable stress. The ultimate result is widening of cracks and buckling of
furnace shell and thus reducing the life of monolithic lining as well as furnace shell.
There has therefore been a continuous need for development of design configuration,
material selection and the method of installation for the anchors for fixing cast monolithic
refractory lining on roof and walls of industrial furnaces or kilns, whereby the difference in
the co-efficient of thermal expansion of the anchor material and the lining material would
not cause occurrence of cracks due to dissimilar expansion at the operating furnace

temperature by incorporating some flexibility in connection of such anchors and its support
means and thus eliminating development of cracks and damage of furnace shell wall due
to overheating by hot gases of furnaces flowing into the widened cracks. The invention
would thus save refractory lining from developing cracks and enhance its operating life so
as to reduce downtime and related costs and improve productivity.
OBJECT OF THE INVENTION
The basic object of the present invention is thus directed to developing a novel design
configuration for the anchor systems for cast monolithic/composite lining of industrial
furnace/kilns in order to avoid generation and propagation of cracks on such refractory
lining due to thermal stress while in operation and thereby enhance its operating life.
Another object of the present invention is directed to developing a method of installing
said anchor systems such that said system comprising the anchor support and the anchor
proper together provide flexible support to the refractory lining in order to eliminate
accumulation of thermal stress due to dissimilar expansion of shell and the lining when
operating at high temperatures that lead to cracks/buckling of shell wall.
A further object of the present invention is directed to developing a paired configuration of
the anchor system that favor either mounting on roof or wall of furnace shell/kiln by
welding of the 'anchor support', selectively spaced based on thickness of the refractory
lining while the top 'anchor proper' gets embedded in the monolithic castable providing
adequate support while also allowing option for free and flexible expansion without any
stress accumulation.
A still further object of the present invention is directed to developing a paired
configuration of the anchor system that favor mounting on roof or wall of furnace
shell/kiln, either in the form of 'V or 'Y' or 'L' type and are made of stainless steel rods or
plates of preferred size and geometric shapes based on location/application/lining
thickness.
A still further object of the present invention is directed to developing a paired
configuration of the anchor system specially designed stainless steel conjugate/linear-pair

anchors are used for application of Low Cement Castable (LCC) monolithic refractory to
take care of mismatch in thermal expansion of refractory lining and metallic shell and thus
preventing development of cracks.
A still further object of the present invention is directed to developing a paired
configuration of the anchor system for monolithic refractory lining of industrial
furnace/kilns wherein conjugate anchor systems are installed on roof of furnaces and also
for vertical walls with lining thickness ranging between 150-300mm.
A still further object of the present invention is directed to developing a paired
configuration of the anchor system for monolithic refractory lining of industrial
furnace/kilns wherein the Linear pair anchor systems are applied for composite lining
design where there is provision for brick lining adjacent to the shell and monolithic working
lining, the thickness of which varies in the range from 300 to 1000mm.
A still further object of the present invention is directed to developing a paired
configuration of the anchor system, wherein the anchor installation on shell wall/roof and
casting of monolithic refractory lining are cured by air heating for about 24 hours at 300°C
or by placing hot ingots in furnace followed by slow heating using burner, before actual
charging and firing of furnace to avoid occurrence of visible cracks even up to an operating
temperature of 1350°C.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is thus directed to an Anchor system for roof
and/or wall of industrial furnaces and the like comprising:
(i) anchor support ;and
(ii) anchor proper,
adapted to favour flexibility of movement of the anchors during use to thereby take care of
mismatch of difference in coefficient of thermal expansion between the shell and
monolithic refractory structure.

Another aspect of the present invention directed to said Anchor systems comprising a
plurality of combination of anchor support and anchor proper, selectively installed on
furnace roof/wall in a manner to provide a flexible support for refractory lining;
said anchor proper comprising two types of anchors-(i) Conjugate anchors and (ii) Linear
Pair anchors and
both said anchor support and anchor proper made of stainless steel material.
A further aspect of the present invention directed to said Anchor system for refractory
lining of industrial furnaces wherein said anchor support is made of stainless steel plates,
preferably 6-10 mm thick, depending on refractory lining thickness.
A still further aspect of the present invention directed to said Anchor system wherein, said
conjugate anchors are combination of two Y-type anchors which are complementary to
each other and adapted to be combined together in two ways, said two types preferably
installed alternately.
According to yet another aspect of the present invention directed to said An Anchor
system, wherein said conjugate anchors are made up stainless steel rod having diameter
in the range of 8-16 mm, depending upon the thickness of monolithic lining.
Importantly also in said Anchor system for refractory lining of industrial furnaces, wherein
said linear pair anchors are having combination of L-Type and Y-Type anchors, joined
linearly to thereby ensure a flexible connection between the lining and the shell wall.
A still further aspect of the present invention directed to said Anchor system according to
the present invention, wherein said linear pair anchors having L-type portion of anchor
made up of 8-16 mm stainless steel rod and V-type portion of anchor is made up of 6-12
mm thick and 20-35 mm wide stainless steel plates, depending upon the lining thickness
of monolithic refractory.
A still further aspect of the present invention directed to said Anchor system, wherein said
conjugate anchors system is most suitable for roof of the furnaces, although can also be
used in vertical walls where the lining thickness vary in the range of 150 - 300 mm.

According to another aspect of the present invention directed to said Anchor system,
wherein said linear pair anchors system is adapted for composite refractory lining
configuration where there is a provision for brick lining adjacent to the shell and monolithic
working lining having a total lining thickness in the range of 300 - 1000 mm.
A still further aspect of the present invention is directed to a method for installation of the
anchor system comprising,
(i) providing said conjugate anchors comprising two 'Y' type anchors combined in
two ways which are complimentary to each other, installed preferably in pairs
separated by a selective distance depending on the size of anchors and
thickness of monolithic lining, said two Y-type anchor combinations installed
alternately along the length of the beam more preferably on roof or on walls of
industrial furnace such as on the beams of roof of ignition hearth furnace;
said conjugate anchors held straight, during installation, inside the support with
the help of small welding beads at the base of the anchors so that anchors do
not deviate from its position during casting;
after casting with low moisture castable, the beams are air cured, dried and
heated to 300°C, without occurrence of any visible crack, prior to use of the
ignition hearth furnace.
(ii) providing said Linear Pair anchor system comprising a plurality of combination
of L-type and Y- type anchors, installed preferably in soaking pit walls of
reheating furnace of slabbing mills having composite lining configuration
comprising brick lining adjacent to the shell and Low cement castable (LCC)
monolithic working lining, wherein Ceramic fibre of different thickness are
provided in different regions to protect the shell from overheating; and
said Linear pair anchor system attached to the furnace shell through a specially
designed support welded to the furnace shell holding the anchors free from the
shell, providing flexibility of movement of the anchors during use taking care of
mismatch of difference in coefficients of thermal expansion between shell metal
and monolithic refractory structure, and thus reducing the chances of cracks in

the monolithic structures or buckling of furnace shell during use, after drying
and heating up to 1350°C.
According to yet another aspect of the present invention is directed to a method wherein
for installing said linear pair anchor system said furnace is dismantled and cleaned
properly and bottom bricks are laid first except top two layers and then walls are made
upto a height of 1500 mm using bricks;
A still further aspect of the present invention is directed to a method of installation for the
anchor systems comprising providing Linear Pair anchors comprising combination of L-
Type and Y-Type anchors , wherein Longer leg of L-type anchor is threaded on tip end up
to 40-50mm and provided with two suitable nuts, such that said Y-type anchor is joined
linearly with the L-type anchor with the help of nut and bolt assembly, while the other end
of the L-type anchor fits into the support, to thereby providing a flexible connection
between lining and the furnace shell to avoid cracks in lining, comprising
providing said L-type anchor portion made up of stainless steel rod 8-16 mmø,
more preferably 12 mmø depending upon the lining thickness of monolithic
refractory;
providing said Y-type anchor made up of 6-12 mm thick more preferably 8mm
thick and 20-35 mm more preferably 30 mm wide stainless steel plates that is
bend at 90° towards the end of the leg of the anchor at a distance of 40-50 mm
and having a hole of 10-18 mm ø drilled in said bend portion of the Y-type
anchor depending on and to accommodate the diameter of said L-type portion
therethrough;
drying and heating of the furnace lining done by placing hot ingots in the
furnace followed by slow heating using burner, prior to putting the furnace in
normal operation, without occurrence of any visible cracks in the lining
enhancing life of the soaking pit walls by about three-fold.
The present invention and its objects and advantages are described in greater details with
reference to the following accompanying non limiting illustrative figures.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURE
Figure 1: is the illustration of the conventional method of anchor installation in furnace
/kilns wherein base of the anchors is welded to the shell.
Figure 2: is the illustration of the conjugate type anchor proper according to an
embodiment of the present invention showing anchors of the two-Y type configuration
combined together in two ways which are complementary to each other.
Figure 3: is the illustration of the linear pair type anchor proper according to an
embodiment of the present invention comprising combined 'L' type and 'Y' type SS
anchors, providing flexible connection of the monolithic refractory lining with shell wall via
anchor proper and the anchor support.
Figure 4: is the illustration of the general arrangement of the SS anchor assembly along
with layers of ceramic fibres, firebricks and cast monolithic LCC based refractory lining
installed on furnace shell wall.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING FIGURES
Reference is first invited to the accompanying Figure 1 that illustrates the conventional
method of anchor installation wherein the base of anchor is welded to the furnace/shell
wall. Conventionally, V- or Y-T'ype anchors are used for installation of monolithic
refractories, depending on the lining thickness of monolithic refractory on furnace shell
wall/roof. V-type anchors are usually selected for small thickness below 150 mm, whereas
Y-type anchors are used for higher thicknesses over 150mm. During installation of
monolithic refractories, base of the anchors are welded directly to the furnace shell or kiln.
Such anchors are conventionally used in ladles, tundishes, roof of the ignition hearth
furnace of Sinter plant, rotary kiln, etc. It has been experienced in the existing art that the
coefficient of thermal expansion of the refractory material and the metallic shell are having
substantial difference. As a consequence of this, conventional anchor installation causes
undesirable stress accumulation in the monolithic structure as well as in the furnace shell.
These undesirable developed stresses cause cracks in the monolithic structure. Once

cracks are developed in the lining, hot gases inside the furnace/kiln enter the cracks and
propagate through gap near to the furnace shell and thus increasing the shell
temperature. Increase in shell temperature causes further increase in undesirable stress.
The ultimate result of such stress accumulation and over heating is widening of cracks and
buckling of furnace shell and thus reducing the life of monolithic lining as well as furnace
shell.
Reference is now invited to the accompanying Figure 2, that illustrates the modified
anchor configuration and its installation directed to eliminating the problems of crack
development and overheating/buckling of shell by the hot furnace gases. It has already
been stated that to combat the stated problems of prior art, the present invention makes
use of modified anchor configurations that can be broadly divided into two parts.
(i) Anchor Support;
(ii) Anchor Proper;
Both the anchor support and the anchor proper are made up of stainless steel of grade SS
304, of selective section/size. Design of anchor support is such that the base of the anchor
proper can fit properly with support portion and said anchor hangs freely after installation
such that the problem of accumulation of thermal stress do not lead to development of
cracks. There is free movement of anchor proper inside the anchor support. The anchor
support is properly welded to the furnace/kiln shell. These anchor supports are made out
of 6-10 mm thick stainless steel plates depending on the size of anchor proper and lining
thickness.
Anchor proper are further configured into two categories according to the anchor design of
the present invention, as follows:
1. Conjugate Anchors;
2. Linear Pair Anchors;
The type-I and type-II anchors, as illustrated in the accompanying Figure 2, constitute
the conjugate anchors. These anchors are different combinations of two Y-type of anchors.
Two Y-type anchors are combined together in two ways which are complimentary to each
other. These anchors are made up of 8-16 mm diameter Stainless Steel rod depending
upon the thickness of monolithic lining. These are called conjugate anchors because they

are complimentary to each other and are always used in pairs separated by a suitable
distance depending on the size of anchors and lining thickness. This type of anchor system
is most suitable for roof of the industrial furnaces. However, it can also be used for lining
on vertical walls. This anchor system has been successfully used in the beams of roof of
ignition hearth at considerably high operating temperatures in the applicants' Bokaro steel
plant reliably without crack for considerable period. The result has thus been very
encouraging as compared to conventional anchor system.
Reference is now invited to accompanying Figure 3, that illustrates the Linear pair anchor
configuration according to the present invention and are basically combination of L-Type
and Y-Type anchors. They are called linear pair anchors because L-Type and Y-Type
anchors are joined linearly with the help of nut and bolt assembly. L-type portion is made
up of 8-16 mm stainless steel rod (SS 304) depending upon the lining thickness of
monolithic refractory. Longer leg of L-type anchor is threaded on tip end over about 40-
50mm length and is provided with two suitable nuts on said threaded portion. The other
end of the L-type anchor fits into the support. The second part, that is the Y-type anchor is
made up of 6-12 mm thick and 20-35 mm wide stainless steel plates. There is a bend at
90° towards the end of the leg of the anchor at a distance of 40-50 mm. A hole is made in
this bend portion of 10-18 mm depending on the diameter of the L-type portion. Y-type
anchor is inserted into the L-type anchors through this hold and tightened by means of the
two nuts provided on the threaded portion, as shown in the accompanying Figure 3, thus
completing the linear pair anchor system.
Reference is now invited to the accompanying Figure 4 that illustrates the arrangement of
the General anchor assembly and lining design. More importantly, such type of anchor
system is suitable for composite lining design where there is a provision for brick lining
adjacent to the shell and monolithic working lining. This anchor system has been used
successfully in walls of one of the soaking pits of Bokaro steel Plant. Ceramic fibre of
different thickness in different regions has been used to protect the shell from
overheating. It is basically a composite lining design in which LCC has been used in
combination with bricks.
Importantly, during the installation of such anchor systems, the bases of anchor proper
are not welded to the furnace shell. They are attached to the furnace shell through a
specially designed support. The supports are welded to the furnace shell holding the

anchors free from the shell. Thus, there is a flexibility of movement of the anchors during
use. This flexibility of movement of anchors take care of mismatch of difference in
coefficients of thermal expansion between shell and monolithic refractory structure. This in
turn helps reducing the chances of cracks in the monolithic structures and thereby
buckling of furnace shell due to over heating with hot gases during use. The performance
of the lining of walls of this pit has been exceedingly well and longer operating life of
refractory lining achieved. No cracks were found to develop anywhere in the walls after
drying and heating up to 1350°C. This type of lining design incorporating linear pair anchor
system, has been developed and implemented in more pits to achieve economy in
operation, less down time and higher productivity.
Results of modified anchor system as observed in actual application are as follows:
a. Conjugate Anchors has been used in the end beam of ignition hearth furnace, with
severe condition of beam. Y-type Anchors systems- type I and II, were used alternately
along the length of the beam. While installing, the anchors are held straight inside the
support with the help of small welding beads at the base of the anchors such that the
anchors do not deviate from its position during casting. After casting with low moisture
castable, the beams were air cured, dried and heated to 300°C prior to be used in the
ignition hearth furnace. No visible cracks were observed after heating the beams for
considerable period. Marked improvement in the performance of the beam has been
observed as compared to conventional practice.
b. Linear Pair Anchors were used in the composite lining of soaking pit walls of reheating
furnace of Slabbing Mill at the applicants' Bokaro Steel plant, as illustrated schematically in
general layout shown in Figure 4. The furnace was dismantled and cleaned properly.
Bottom bricks were laid first except top two layers and then the walls were made up to a
height of 1500mm using first lightweight and then High Grog Fire Bricks. Specially
configured stainless steel (SS 304) Linear pair anchors have been installed for application
of low cement castable (LCC) to take care of mismatch in thermal expansion of refractory
lining and metallic shell and thus preventing development of cracks in the monolithic
lining. After the lining of wall, the remaining two layers were placed in the bottom. After
completion of lining, it is air cured for 24 hours. Then air injection was given for 24 hours
after closing the furnace. There after the bottom of furnace is prepared using coke breeze.

Complete drying and heating of the furnace has been carried out placing hot ingots in the
furnace, followed by slow heating using burner, after which the furnace was put in normal
operation. No visible cracks are observed anywhere in the lining after heating. The furnace
is running successfully with life of the soaking pit walls prolonged by about three-times
compared to conventional configuration.
It is thus possible by way of the present invention to develop improved anchor systems for
the cast monolithic refractory lining of industrial furnaces/kilns and method of installation
thereof, such as in the ladles, tundishes, roof of the ignition hearth furnace of Sinter plant,
rotary kiln and the like, directed to eliminating occurrences of cracks in said refractory
lining while the furnace is in operation due to accumulation of thermal stress because of
dissimilarity in the coefficient of thermal expansion of shell metal and the lining material
and there by overheating of the shell wall and its resultant buckling leading to reduction in
the furnace operating life and its yield/productivity. In modified anchor systems, there is a
flexibility of movement of the anchors during use. This flexibility of movement of anchors
takes care of mismatch of difference in coefficients of thermal expansion between shell
and monolithic/composite refractory structure. This helps in reducing the chances of cracks
in the monolithic structures and buckling of furnace shell while in operation. While the
Conjugate anchors system is suitable for roof of the furnaces and can also be used in
vertical walls for lining thickness varying in the range of from 150 - 300 mm, Linear pair
anchors system is suitable for composite lining design where there is a provision for brick
lining adjacent to the shell in combination with monolithic working lining, and the lining
thickness may varying in the range of from 300 - 1000 mm. The present invention is thus
capable of providing longer life of the cast monolithic lining of industrial furnaces/kilns on
roofs/walls free of developing any cracks/ damage to shell walls, reducing down time and
related costs and thus improving productivity and yield, making the anchor system and its
method of installation according to the invention capable of wide industrial application in
the large integrated steel plants and similar other plants using such furnaces/kilns.

We Claim:
1. Anchor system for roof and/or wall of industrial furnaces and the like comprising:
i) anchor support ;and
ii) anchor proper,
adapted to favour flexibility of movement of the anchors during use to thereby take care of
mismatch of difference in coefficient of thermal expansion between the shell and
monolithic refractory structure.
2. Anchor system as claimed in claim 1 comprising a plurality of combination of anchor
support and anchor proper, selectively installed on furnace roof/wall in a manner to
provide a flexible support for refractory lining;
said anchor proper comprising two types of anchors-(i) Conjugate anchors and (ii) Linear
Pair anchors and
both said anchor support and anchor proper made of stainless steel material.
3. Anchor system as claimed in anyone of claims 1 or 2 wherein said anchor support is
made of stainless steel plates, preferably 6-10 mm thick, depending on refractory lining
thickness.
4. Anchor system as claimed in anyone of claims 1 to 3 , wherein said conjugate anchors
are combination of two Y-type anchors which are complementary to each other and
adapted to be combined together in two ways ,said two types preferably installed
alternately.
5. An Anchor system as claimed in anyone claims 1 to 4, wherein said conjugate anchors
are made up stainless steel rod having diameter in the range of 8-16 mm, depending upon
the thickness of monolithic lining.

6. Anchor system as claimed in anyone of claims 1 to 5, wherein said linear pair anchors
are having combination of L-Type and Y-Type anchors, joined linearly to thereby ensure a
flexible connection between the lining and the shell wall.
7. Anchor system as claimed in claim 6, wherein said linear pair anchors having L-type
portion of anchor made up of 8-16 mm stainless steel rod and Y-type portion of anchor is
made up of 6-12 mm thick and 20-35 mm wide stainless steel plates, depending upon the
lining thickness of monolithic refractory.
8. Anchor system as claimed in anyone claims 1 to 7, wherein said conjugate anchors
system is most suitable for roof of the furnaces, although can also be used in vertical walls
where the lining thickness vary in the range of 150 - 300 mm.
9. Anchor system as claimed in anyone claims 1 to 8, wherein said linear pair anchors
system is adapted for composite refractory lining configuration where there is a provision
for brick lining adjacent to the shell and monolithic working lining having a total lining
thickness in the range of 300 - 1000 mm.
10. A method for installation of the anchor system as claimed in anyone of claims 1 to 9
comprising,
i) providing said conjugate anchors comprising two 'Y' type anchors combined in
two ways which are complimentary to each other, installed preferably in pairs
separated by a selective distance depending on the size of anchors and
thickness of monolithic lining, said two Y-type anchor combinations installed
alternately along the length of the beam more preferably on roof or on walls of
industrial furnace such as on the beams of roof of ignition hearth furnace;
said conjugate anchors held straight, during installation, inside the support with
the help of small welding beads at the base of the anchors so that anchors do
not deviate from its position during casting;
after casting with low moisture castable, the beams are air cured, dried and
heated to 300°C, without occurrence of any visible crack, prior to use of the
ignition hearth furnace.

ii) providing said Linear Pair anchor system comprising a plurality of combination
of L-type and Y- type anchors, installed preferably in soaking pit walls of
reheating furnace of slabbing mills having composite lining configuration
comprising brick lining adjacent to the shell and Low cement castable (LCC)
monolithic working lining, wherein Ceramic fibre of different thickness are
provided in different regions to protect the shell from overheating; and
said Linear pair anchor system attached to the furnace shell through a specially
designed support welded to the furnace shell holding the anchors free from the
shell, providing flexibility of movement of the anchors during use taking care of
mismatch of difference in coefficients of thermal expansion between shell metal
and monolithic refractory structure, and thus reducing the chances of cracks in
the monolithic structures or buckling of furnace shell during use, after drying
and heating up to 1350°C.
11. A method as claimed in claim 10 wherein for installing said linear pair anchor system
said furnace is dismantled and cleaned properly and bottom bricks are laid first except top
two layers and then walls are made upto a height of 1500 mm using bricks;
12. A method as claimed in anyone of claims 10 or 11 comprising providing Linear Pair
anchors comprising combination of L-Type and Y-Type anchors , wherein Longer leg of L-
type anchor is threaded on tip end up to 40-50mm and provided with two suitable nuts,
such that said Y-type anchor is joined linearly with the L-type anchor with the help of nut
and bolt assembly, while the other end of the L-type anchor fits into the support, to
thereby providing a flexible connection between lining and the furnace shell to avoid
cracks in lining, comprising
providing said L-type anchor portion made up of stainless steel rod 8-16 mmø,
more preferably 12 mmø depending upon the lining thickness of monolithic
refractory;
providing said Y-type anchor made up of 6-12 mm thick more preferably 8mm
thick and 20-35 mm more preferably 30 mm wide stainless steel plates that is
bend at 90° towards the end of the leg of the anchor at a distance of 40-50 mm

and having a hole of 10-18 mm ø drilled in said bend portion of the Y-type
anchor depending on and to accommodate the diameter of said L-type portion
therethrough;
drying and heating of the furnace lining done by placing hot ingots in the
furnace followed by slow heating using burner, prior to putting the furnace in
normal operation, without occurrence of any visible cracks in the lining
enhancing life of the soaking pit walls by about three-fold.
13. An Anchor system for refractory lining on roof/wall of industrial furnace adapted to
eliminate cracks and a method for installation of such system for monolithic and composite
lining as hereindescribed with reference to the non limiting illustrative figures, in particular
figures 2,3 and 4.

Anchor systems for retaining the cast monolithic/composite refractory lining and method
for installation thereof in various industrial furnaces to enhance the life of the refractory
lining avoiding cracking due to dissimilar thermal expansion of shell and lining. The anchor
system according to the invention are broadly divided into two parts viz. (i) the Anchor
Support & (ii) the Anchor proper, both made of stainless steel. The anchor proper is further divided into two types viz, (i) the Conjugate Anchors and (ii) Linear pair Anchors, based on specific applications. Conjugate anchors comprise two Y-type of anchors combined in two different ways that are complementary to each other. The Linear pair anchors are combination of L-type and Y-type anchors, the two being joined flexibly and linearly. Free movement of anchor proper relative to anchor support is allowed in the installation arrangement. Present: anchor systems for refractory lining of furnaces thus avoid loss of production due to cracks, improving productivity of industrial furnaces/kilns and hence capable of wide industrial application.