Title of Invention	FURNACE REFRACTORY BRICKS TO ACCOMMODATE HEATING COILS FOR BUILDING FURNACE FLOOR / BED AND METHOD OF PRODUCING THE SAME
Abstract	This invention relates to a furnace refractory bricks to accommodate heating coils for building furnace floor/ bed and a method of producing the bricks furnace refractory bricks for building furnace floor / bed with improved self life and for optimized uniform heating of furnace comprising: a two part split assembly of bottom and top cover part, the bottom part consisting of a base (01), two side walls (02), a divider (03) dividing a gap between the side walls creating a multiple coil grooves (04) running along the length of the brick side walls (02) to accommodate heating coils (14), a stepped bearing surface (05) provided on both top surfaces of the side walls, a lifting relief (06) provided at the upper surface of a centrally cut midsection of the side walls to form slots (07) for converting and dissipating heat generated by the heating coil; the top cover consisting of a central part (08) with two side flanges (09) running along the length of the top part a lifting relief (10) forming sloping passages to form a hollow cavity (12), a bottom surface (11) provided below the flange sit over the stepped shape in bearing surfaces (05) of the bottom part in matching relationship, convection flutes (13) provided below the central part (08) communicating the hollow cavity (12) via the coil grooves to the exterior furnace space to channel away most of heat of coil by convention into the furnace thus enabling optimized, uniform heat transfer of heating coil.

Title of Invention

FURNACE REFRACTORY BRICKS TO ACCOMMODATE HEATING COILS FOR BUILDING FURNACE FLOOR / BED AND METHOD OF PRODUCING THE SAME

Abstract

This invention relates to a furnace refractory bricks to accommodate heating coils for building furnace floor/ bed and a method of producing the bricks furnace refractory bricks for building furnace floor / bed with improved self life and for optimized uniform heating of furnace comprising: a two part split assembly of bottom and top cover part, the bottom part consisting of a base (01), two side walls (02), a divider (03) dividing a gap between the side walls creating a multiple coil grooves (04) running along the length of the brick side walls (02) to accommodate heating coils (14), a stepped bearing surface (05) provided on both top surfaces of the side walls, a lifting relief (06) provided at the upper surface of a centrally cut midsection of the side walls to form slots (07) for converting and dissipating heat generated by the heating coil; the top cover consisting of a central part (08) with two side flanges (09) running along the length of the top part a lifting relief (10) forming sloping passages to form a hollow cavity (12), a bottom surface (11) provided below the flange sit over the stepped shape in bearing surfaces (05) of the bottom part in matching relationship, convection flutes (13) provided below the central part (08) communicating the hollow cavity (12) via the coil grooves to the exterior furnace space to channel away most of heat of coil by convention into the furnace thus enabling optimized, uniform heat transfer of heating coil.

Full Text	-2- BROAD AREA OF THE INVENTION The invention broadly relates to furnace that are used for industrial heat treatment. Particularly it concerns electrically heated furnaces that have refractory brick lining SPECIFIC FIELD OF THE INVENTION The invention relates to electrically heated furnaces, used for heating large objects as is done in metal smelters, forging processes and heat treatment processes. More specifically it involves the shape, arrangement and performance of refractory bricks that house the heating coils and also electrically isolate them from the objects to be heated (job). BACKGROUND & STATE OF ART OF THE INVENTION In electrically heated industrial furnaces, the heating coils are placed in the furnace space in such a manner that the heat is distributed all over as uniformly as possible. The passage of electric current through the heating elements causes -3- "ohmic heating", that is proportional to the current carried and that of the electrical resistance of the coil material. The numerical value of energy transferred is usually equal to I2R, where I is the current that flows, expressed in amperes and R is the resistance, expressed in Ohms. One of the primary requirements of the construction of such furnaces is that the heating coil that carries current is electrically isolated from the rest of the surroundings. At the same time, ensuring effective transfer of heat from the heating coil to the entire furnace space is also of great importance. Usually heating elements are mounted on the sidewalls and top wall, from where heat is transferred by "direct radiation" to the charge (job); whereas coils placed at the floor of the furnace or below the "furnace table" manage to transfer the heat only by conducting to the refractory floor and there further by contact or radiation to the "charge". This heat transfer compared to the direct radiation heat transfer is less intense and invariably takes a longer time for a given amount of heat to be transferred. Therefore, the bottom portion of any 'charge' takes the longest time before getting heated to any specified temperature. -4- SHORTCOMINGS OF STATE OF ART Typically the furnace floor refractory bricks are manufactured with profiled grooves or 'coil receptacles' for accommodating the heating elements. The 'as- moulded' bricks are laid in position and then the electric heating coils are externally inserted from outside. The predominant mode of heat transfer from the coil to furnace space is conduction and diffuse radiation from the brick surface. The conventional method inherently suffers from the disadvantages that heat energy get accumulated within the brick causing overheating and failure of heating elements. Additionally the furnace bricks get damaged due to melting of coils. Longer duration of heating cycles due to poor heat energy evacuation from the heating coils results in more energy consumption for the given load. In an attempt to address and solve some of the above problems, the proposed innovative bricks are configured in two-parts. This improved configuration facilitates easy assembly, handling and maintenance. Most importantly, the novel brick permits efficient evacuation of heat from the heating coils to the furnace space, by a combined multi-mode heat transfer that employs all of convection, conduction and radiation of heat. -5- DESCRIPTION OF THE INVENTION It is an object of the invention to enhance the performance of furnace bricks, through a unique constructive design that houses the heating coil as well as forms the refractory floor / bed for electrically heated furnaces. Another object is to prescribe the method of employing such bricks to achieve efficient operation, enhanced performance and ease of maintenance. A still another objective of the invention is to accommodate instrument leads like thermocouples, pressure probes, potential probes etc. in the grooves formed in the brick instead of heating coils. The innovative heating-element-holding refractory bricks for furnaces, comprises of two main parts. The bottom part holds the electric heating element. This part is made of suitable refractory material for the required operating temperature ranges. The shape and size of this brick too depend on the rating and size of the heating element that it will accommodate. The bricks have suitable provisions to make them stackable horizontally over the required length of heating element. -6- The top part acts as a protection cover for the heating coils. Convention openings are provided in both the parts. These openings are so located that no loose object can fall or come into contact with the heating coil that is contained within. Further, the location and shape of these openings ensure that the heat energy released by the electric heating elements from the bottom part will be efficiently evacuated and converted out to the hearth. The top part remains assembled on to the bottom part during normal furnace operation but can be slid away easily for gaining access to heating coils or for any other maintenance need that may warrant removal/replacement of heating coils. The said split refractory bricks are configured into shapes such as parallelogram, cubic, cylindrical, ellipsoidal form etc. According to the invention there is provided furnace refractory bricks to accommodate heating coils for building furnace floor with improved self-life and for optimized uniform heating of furnace comprising - a two part split assembly of bottom and top cover part, the bottom part consisting of a base, two side walls, a divider dividing a gap between the side walls creating a multiple coil grooves running along -7- the length of the brick side walls to accommodate heating coils, a stepped bearing surface provided on both top surfaces of the side walls, a downward slopped lifting relief provided at the upper surface of a centrally cut mid-section of the side walls to form slots for converting and dissipating heat generated by the heating coil; - the top cover consisting of a central part with two side flanges running along the length of the top part, a lifting relief forming sloping passages to form a hollow cavity, a bottom surface provided below the flange sit over the bearing surfaces of the bottom part in matching relationship, convection flutes provided below the central part communicating the hollow cavity via the coil grooves to the exterior furnace space to channel away most of heat of coil by convection into the furnace thus enabling optimized, uniform heat transfer of heating coil. The present invention relates also to a method of producing furnace refractory bricks to accommodate heating coils for building furnace floor/ bed with improved self-life and optimized uniform heating of furnace comprising the steps -8- of preparing refractory brick concrete from refractory constituents, and bonding agents on mixing and casting the mix into two separate split part assembly in two preformed moulds and curving the casted two parts to constitute a bottom part consisting of a base, two side walls, a divider dividing a gap between the side walls thus creating a multiple coil grooves running along the length of the brick to accommodate heating coils, a stepped bearing surface provided on both top surfaces of the side walls, a downward slopped lifting relief provided at the upper surface of a centrally cut mid-section of the side walls to from slots for converting and dissipating heat generated by the heating coil; a top cover part consisting of a central part with two side flanges running along the length of the top part, a lifting relief forming a slopping passages to form a hollow cavity provided below the flange sit when put over the bearing surfaces of the bottom part, convection flutes provided below the central part communicating with the hollow cavity via the coil grooves to the exterior furnace space to channel away the heat of heating coil by convection into the furnace to enable uniform heat transfer of heating coil, when the said top part is placed over the bottom part and the furnace walls when formed with mating brick assemblies are heated by the coil provided in the coil grooves in the brick assemblies. -9- The invention will be better understood by the following description with reference to the accompanying drawings in which Figure 1 depicts prior art arrangement of heating coil. Figure 2 depicts the bottom part of the innovative coil-holding brick according to the present invention. Figure 3 depicts the top cover as top and bottom view that is assembled on top of the coil-holder during normal operation according to the present invention. Figure 4 shows a typical assembly of the refractory brick with heating coils and top cover in place according to the present invention. A typical conventional arrangement of heating coil (C) and one piece refractory brick (A) is depicted in Figure-1. -10- The electric heating coils (C) are shrouded by the coil cavity (B) from the furnace space so that oxide scales or other loose objects do not fall on the coils or come into contact with the coils, causing a potential electric short-circuit or grounding. Further, the heat energy from the bottom heating elements does not reach out from the bricks to the furnace surface efficiently, because of which the heat energy released by the heating elements (C) gets accumulated within the brick, often leading to over heating and mechanical failure of the heating elements. Owing to the above, the uniformity of temperature distribution all around the job suffers owing to the less efficient heat transfer from bottom surface compared to the sidewalls and roof. Additionally, replacement of the faulty or damaged heating elements poses difficulty whenever a damaged element melts and gets stuck inside the element groove (B) of the brick. Because of this the entire brick housing the faulty element warrants replacement, though the brick by itself could be undamaged. This in turn cause the furnace downtime to increase, and result in difficulties of the heating elements to be matched and inserted on to the other bricks that are already in place. -11- In Figures 2, 3 and 4 the bottom part or the "coil holder" essentially has a 'base' (1) that is preferably rectangular in shape. There are two 'sidewalls' (02) that run the length of the coil-holder. The gap between the two sidewalls is separated by a 'divider' (03) creating the heating 'coil groove' (04). There can also be more than one divider (03), in order to create multiple 'coil grooves'. The sidewalls (2) have a stepped shape that receive and act as a stopper for the top cover shown in figure 3. The bearing surfaces' (05) support the hearth plate, "charge" or "job" that the furnaces hold. The height of the step from the inner floor surface of the base (1) is tailor made for the chosen coil type. The two sidewalls (02) have 'lifting relief (06) about the mid-section of the longer sides to permit easier handling while assembling and during maintenance. The lifting relief (06) also defines a rectangular or other geometrical slot of a 'convection opening' (07) that helps to convert away and dissipate the heat generated by the heating coils. The lifting relief (06) has a specific downward slope that helps to prevent any foreign matter like oxide scale etc from entering the heating coil groove from furnace space. -12- The double hollow feature (12) in the central part on the top half of the brick is acting like a collection chute for the heat energy and release them through convection flutes (13) so that the energy gets distributed uniformly from the bottom coils throughout the furnace. The top cover has a 'central part' (08) and two side flanges (09) that run the length of the brick. The top cover also has lifting relief (10) and sloping passages identical to that of the bottom part. The bottom surfaces (11) of the flange will sit over the stepped shape in bearing surfaces (05) of bottom part during assembly. There is a 'hollow cavity' (12) on the underside of the top cover. This aids heat from coils to be converted away. There are 'convection flutes' (13) provided below the central part, that communicate from the hollow cavity (12) to the exterior that help effectively channeling away most of the heat by convention into the furnace. Figure 4 shows a typical assembly with heating coils (14) placed in the coil grooves (4). As can be seen the brick assembly with repeated features both along length and width for making a mosaic of brick-lined furnace floor. -13- The innovative 'two-part' assembly results in significant advantage such as: 1. The heating elements can be assembled from top easily. 2. The ventifation openings provided on the bottom bricks and the top cover will allow the complete release of heat energy to reach the bottom hearth surface. 3. The Scales from the heat treatment jobs will not fall on the bottom heating elements. 4. Failed bottom brick alone can be replaced. 5. Condition of the heating elements by visual / testing can be done by just opening the top part. 6. Cleaning the coil zone and maintaining them are easier. 7. The scales can be wiped out easily with out disturbing the element / brick assembly in a very least time. -14- 8. Handling and installing are very easier and skill not required. 9. Interchangeability of the bricks and top cover assembly. 10. Easy for manufacture and hence cheaper. Though the invention has been narrated and illustrated with a preferred embodiment the same should not be read and construed in a restrictive manner as various adaptations, modifications, alterations are possible within the scope and limit of the invention as defined in the encompassed appended claims. -15- WE CLAIM 1. Furnace refractory bricks to accommodate heating coils for building furnace floor/ bed with improved self life and for optimized uniform heating of furnace comprising: - a two part split assembly of bottom and top cover part, the bottom part consisting of a base (01), two side walls (02), a divider (03) dividing a gap between the side walls creating a multiple coil grooves (04) running along the length of the brick side walls (02) to accommodate heating coils (14), a stepped bearing surface (05) provided on both top surfaces of the side walls, a lifting relief (06) provided at the upper surface of a centrally cut mid-section of the side walls to form slots (07) for converting and dissipating heat generated by the heating coil; - the top cover consisting of a central part (08) with two side flanges (09) running along the length of the top part a lifting relief (10) forming sloping passages to form a hollow cavity (12), a bottom -16- surface (11) provided below the flange sit over the bearing surfaces (05) of the bottom part in matching relationship, convection flutes (13) provided below the central part (08) communicating the hollow cavity (12) via the coil grooves to the exterior furnace space to channel away most of heat of coil by convection into the furnace thus enabling optimized, uniform heat transfer of heating coil. 2. Furnace refractory bricks as claimed in claim 1 wherein the space below bearing surface (05) forms a cylindrical or other preferred geometrical space to receive cylindrically shaped heating coils. 3. Furnace refractory bricks as claimed in claims 1 and 2 wherein when a furnace is heated by other means than that of heating coil, instrument leads like thermocouples, pressure probes, potential probes etc. are housed in the grooves (04) instead of heating coils. 4. Furnace refractory bricks as claimed in the preceding claims wherein the said bricks are configured in geometrical shapes such as parallelogram, cubic, cylindrical, ellipsoidal or other geometrical form used for building floor of a typical furnace. -17- 5. Furnace refractory bricks as claimed in claim 1 wherein in the said bricks multiple dividers (08) are constructed to provide multiple groves (04) in the brick assembly. 6. Furnace refractory bricks as claimed in the preceding claims wherein the furnace walls formed with the said bricks enable easy maintenance by not allowing any scales from the heat treated jobs on the heating elements, easy replacement of failed bottom brick without disturbing the rest furnace walls, easy installation and inspection of heating coil by opening the top part of the refractory brick assembly. 7. A method of producing furnace refractory bricks to accommodate heating coils for building furnace floor / bed with improved self life and optimized uniform heating of furnace comprising the steps of preparing refractory brick concrete from refractory constituents, crushed fire bricks and bounding agents on mixing and casting the mix into two separate split part assembly in two preformed moulds and curving the cast two parts to constitute a bottom part consisting of a base (01), two side walls (02) a divided (03) dividing a gap between the side walls thus creating a multiple -18- coil grooves (04) running along the length of the brick to accommodate heating coils (14), a stepped bearing surface (05) provided on both top surfaces of the side walls, a downward slopped lifting relief (06) provided at the upper surface of a centrally cut mid-section of the side walls (02) to from slots (07) for converting and dissipating heat generated by the heating coil (14); a top cover part consisting of a central part (08) with two side flanges (09) running along the length of the top part, a lifting relief (10) forming a slopping passages to form a hollow cavity (12) provided below the flange sit when put over the bearing surfaces (05) of the bottom part, convection flutes (13) provided below the central part (08) communicating with the hollow cavity (12) via the coil grooves (04) to the exterior furnace space to channel away the heat of heating coil by convection into the furnace to enable uniform heat transfer of heating coil, when the said top part is placed over the bottom part and the furnace walls when formed with mating brick assemblies are heated by the coil (14) provided in the coil grooves (04) in the brick assemblies. 8. A method of producing furnace refractory bricks to accommodate heating coils for building furnace floor / bed with improved self-life and for optimized uniform heating of furnace as herein described. -19- 9. Furnace refractory bricks to accommodate heating coils for building furnace floor/bed with improved self-life and for optimized uniform heating of furnace as herein described and illustrated. Dated this 26th day of March 2007. This invention relates to a furnace refractory bricks to accommodate heating coils for building furnace floor/ bed and a method of producing the bricks furnace refractory bricks for building furnace floor / bed with improved self life and for optimized uniform heating of furnace comprising: a two part split assembly of bottom and top cover part, the bottom part consisting of a base (01), two side walls (02), a divider (03) dividing a gap between the side walls creating a multiple coil grooves (04) running along the length of the brick side walls (02) to accommodate heating coils (14), a stepped bearing surface (05) provided on both top surfaces of the side walls, a lifting relief (06) provided at the upper surface of a centrally cut midsection of the side walls to form slots (07) for converting and dissipating heat generated by the heating coil; the top cover consisting of a central part (08) with two side flanges (09) running along the length of the top part a lifting relief (10) forming sloping passages to form a hollow cavity (12), a bottom surface (11) provided below the flange sit over the stepped shape in bearing surfaces (05) of the bottom part in matching relationship, convection flutes (13) provided below the central part (08) communicating the hollow cavity (12) via the coil grooves to the exterior furnace space to channel away most of heat of coil by convention into the furnace thus enabling optimized, uniform heat transfer of heating coil.

Full Text

-2-
BROAD AREA OF THE INVENTION
The invention broadly relates to furnace that are used for industrial heat
treatment. Particularly it concerns electrically heated furnaces that have
refractory brick lining
SPECIFIC FIELD OF THE INVENTION
The invention relates to electrically heated furnaces, used for heating large
objects as is done in metal smelters, forging processes and heat treatment
processes. More specifically it involves the shape, arrangement and performance
of refractory bricks that house the heating coils and also electrically isolate them
from the objects to be heated (job).
BACKGROUND & STATE OF ART OF THE INVENTION
In electrically heated industrial furnaces, the heating coils are placed in the
furnace space in such a manner that the heat is distributed all over as uniformly
as possible. The passage of electric current through the heating elements causes

-3-
"ohmic heating", that is proportional to the current carried and that of the
electrical resistance of the coil material. The numerical value of energy
transferred is usually equal to I2R, where I is the current that flows, expressed in
amperes and R is the resistance, expressed in Ohms.
One of the primary requirements of the construction of such furnaces is that the
heating coil that carries current is electrically isolated from the rest of the
surroundings. At the same time, ensuring effective transfer of heat from the
heating coil to the entire furnace space is also of great importance. Usually
heating elements are mounted on the sidewalls and top wall, from where heat is
transferred by "direct radiation" to the charge (job); whereas coils placed at the
floor of the furnace or below the "furnace table" manage to transfer the heat
only by conducting to the refractory floor and there further by contact or
radiation to the "charge". This heat transfer compared to the direct radiation
heat transfer is less intense and invariably takes a longer time for a given
amount of heat to be transferred. Therefore, the bottom portion of any 'charge'
takes the longest time before getting heated to any specified temperature.

-4-
SHORTCOMINGS OF STATE OF ART
Typically the furnace floor refractory bricks are manufactured with profiled
grooves or 'coil receptacles' for accommodating the heating elements. The 'as-
moulded' bricks are laid in position and then the electric heating coils are
externally inserted from outside. The predominant mode of heat transfer from
the coil to furnace space is conduction and diffuse radiation from the brick
surface. The conventional method inherently suffers from the disadvantages that
heat energy get accumulated within the brick causing overheating and failure of
heating elements. Additionally the furnace bricks get damaged due to melting of
coils. Longer duration of heating cycles due to poor heat energy evacuation
from the heating coils results in more energy consumption for the given load.
In an attempt to address and solve some of the above problems, the proposed
innovative bricks are configured in two-parts. This improved configuration
facilitates easy assembly, handling and maintenance. Most importantly, the novel
brick permits efficient evacuation of heat from the heating coils to the furnace
space, by a combined multi-mode heat transfer that employs all of convection,
conduction and radiation of heat.

-5-
DESCRIPTION OF THE INVENTION
It is an object of the invention to enhance the performance of furnace bricks,
through a unique constructive design that houses the heating coil as well as
forms the refractory floor / bed for electrically heated furnaces.
Another object is to prescribe the method of employing such bricks to achieve
efficient operation, enhanced performance and ease of maintenance.
A still another objective of the invention is to accommodate instrument leads like
thermocouples, pressure probes, potential probes etc. in the grooves formed in
the brick instead of heating coils.
The innovative heating-element-holding refractory bricks for furnaces, comprises
of two main parts. The bottom part holds the electric heating element. This part
is made of suitable refractory material for the required operating temperature
ranges. The shape and size of this brick too depend on the rating and size of the
heating element that it will accommodate. The bricks have suitable provisions to
make them stackable horizontally over the required length of heating element.

-6-
The top part acts as a protection cover for the heating coils. Convention
openings are provided in both the parts. These openings are so located that no
loose object can fall or come into contact with the heating coil that is contained
within. Further, the location and shape of these openings ensure that the heat
energy released by the electric heating elements from the bottom part will be
efficiently evacuated and converted out to the hearth. The top part remains
assembled on to the bottom part during normal furnace operation but can be slid
away easily for gaining access to heating coils or for any other maintenance need
that may warrant removal/replacement of heating coils. The said split refractory
bricks are configured into shapes such as parallelogram, cubic, cylindrical,
ellipsoidal form etc.
According to the invention there is provided furnace refractory bricks to
accommodate heating coils for building furnace floor with improved self-life and
for optimized uniform heating of furnace comprising
- a two part split assembly of bottom and top cover part, the bottom
part consisting of a base, two side walls, a divider dividing a gap
between the side walls creating a multiple coil grooves running along

-7-
the length of the brick side walls to accommodate heating coils, a
stepped bearing surface provided on both top surfaces of the side
walls, a downward slopped lifting relief provided at the upper surface
of a centrally cut mid-section of the side walls to form slots for
converting and dissipating heat generated by the heating coil;
- the top cover consisting of a central part with two side flanges running
along the length of the top part, a lifting relief forming sloping
passages to form a hollow cavity, a bottom surface provided below the
flange sit over the bearing surfaces of the bottom part in matching
relationship, convection flutes provided below the central part
communicating the hollow cavity via the coil grooves to the exterior
furnace space to channel away most of heat of coil by convection into
the furnace thus enabling optimized, uniform heat transfer of heating
coil.
The present invention relates also to a method of producing furnace refractory
bricks to accommodate heating coils for building furnace floor/ bed with
improved self-life and optimized uniform heating of furnace comprising the steps

-8-
of preparing refractory brick concrete from refractory constituents, and bonding
agents on mixing and casting the mix into two separate split part assembly in
two preformed moulds and curving the casted two parts to constitute a bottom
part consisting of a base, two side walls, a divider dividing a gap between the
side walls thus creating a multiple coil grooves running along the length of the
brick to accommodate heating coils, a stepped bearing surface provided on both
top surfaces of the side walls, a downward slopped lifting relief provided at the
upper surface of a centrally cut mid-section of the side walls to from slots for
converting and dissipating heat generated by the heating coil; a top cover part
consisting of a central part with two side flanges running along the length of the
top part, a lifting relief forming a slopping passages to form a hollow cavity
provided below the flange sit when put over the bearing surfaces of the bottom
part, convection flutes provided below the central part communicating with the
hollow cavity via the coil grooves to the exterior furnace space to channel away
the heat of heating coil by convection into the furnace to enable uniform heat
transfer of heating coil, when the said top part is placed over the bottom part
and the furnace walls when formed with mating brick assemblies are heated by
the coil provided in the coil grooves in the brick assemblies.

-9-
The invention will be better understood by the following description with
reference to the accompanying drawings in which
Figure 1 depicts prior art arrangement of heating coil.
Figure 2 depicts the bottom part of the innovative coil-holding
brick according to the present invention.
Figure 3 depicts the top cover as top and bottom view that is
assembled on top of the coil-holder during normal
operation according to the present invention.
Figure 4 shows a typical assembly of the refractory brick with heating coils
and top cover in place according to the present invention.
A typical conventional arrangement of heating coil (C) and one piece refractory
brick (A) is depicted in Figure-1.

-10-
The electric heating coils (C) are shrouded by the coil cavity (B) from the furnace
space so that oxide scales or other loose objects do not fall on the coils or come
into contact with the coils, causing a potential electric short-circuit or grounding.
Further, the heat energy from the bottom heating elements does not reach out
from the bricks to the furnace surface efficiently, because of which the heat
energy released by the heating elements (C) gets accumulated within the brick,
often leading to over heating and mechanical failure of the heating elements.
Owing to the above, the uniformity of temperature distribution all around the job
suffers owing to the less efficient heat transfer from bottom surface compared to
the sidewalls and roof. Additionally, replacement of the faulty or damaged
heating elements poses difficulty whenever a damaged element melts and gets
stuck inside the element groove (B) of the brick. Because of this the entire brick
housing the faulty element warrants replacement, though the brick by itself could
be undamaged. This in turn cause the furnace downtime to increase, and result
in difficulties of the heating elements to be matched and inserted on to the other
bricks that are already in place.

-11-
In Figures 2, 3 and 4 the bottom part or the "coil holder" essentially has a 'base'
(1) that is preferably rectangular in shape. There are two 'sidewalls' (02) that
run the length of the coil-holder. The gap between the two sidewalls is separated
by a 'divider' (03) creating the heating 'coil groove' (04). There can also be more
than one divider (03), in order to create multiple 'coil grooves'. The sidewalls
(2) have a stepped shape that receive and act as a stopper for the top cover
shown in figure 3. The bearing surfaces' (05) support the hearth plate, "charge"
or "job" that the furnaces hold. The height of the step from the inner floor
surface of the base (1) is tailor made for the chosen coil type. The two sidewalls
(02) have 'lifting relief (06) about the mid-section of the longer sides to permit
easier handling while assembling and during maintenance. The lifting relief (06)
also defines a rectangular or other geometrical slot of a 'convection opening' (07)
that helps to convert away and dissipate the heat generated by the heating coils.
The lifting relief (06) has a specific downward slope that helps to prevent any
foreign matter like oxide scale etc from entering the heating coil groove from
furnace space.

-12-
The double hollow feature (12) in the central part on the top half of the brick is
acting like a collection chute for the heat energy and release them through
convection flutes (13) so that the energy gets distributed uniformly from the
bottom coils throughout the furnace.
The top cover has a 'central part' (08) and two side flanges (09) that run the
length of the brick. The top cover also has lifting relief (10) and sloping
passages identical to that of the bottom part. The bottom surfaces (11) of the
flange will sit over the stepped shape in bearing surfaces (05) of bottom part
during assembly. There is a 'hollow cavity' (12) on the underside of the top
cover. This aids heat from coils to be converted away. There are 'convection
flutes' (13) provided below the central part, that communicate from the hollow
cavity (12) to the exterior that help effectively channeling away most of the heat
by convention into the furnace.
Figure 4 shows a typical assembly with heating coils (14) placed in the coil
grooves (4). As can be seen the brick assembly with repeated features both
along length and width for making a mosaic of brick-lined furnace floor.

-13-
The innovative 'two-part' assembly results in significant advantage such as:
1. The heating elements can be assembled from top easily.
2. The ventifation openings provided on the bottom bricks and the top
cover will allow the complete release of heat energy to reach the
bottom hearth surface.
3. The Scales from the heat treatment jobs will not fall on the bottom
heating elements.
4. Failed bottom brick alone can be replaced.
5. Condition of the heating elements by visual / testing can be done by
just opening the top part.
6. Cleaning the coil zone and maintaining them are easier.
7. The scales can be wiped out easily with out disturbing the element /
brick assembly in a very least time.

-14-
8. Handling and installing are very easier and skill not required.
9. Interchangeability of the bricks and top cover assembly.
10. Easy for manufacture and hence cheaper.
Though the invention has been narrated and illustrated with a preferred
embodiment the same should not be read and construed in a restrictive manner
as various adaptations, modifications, alterations are possible within the scope
and limit of the invention as defined in the encompassed appended claims.

-15-
WE CLAIM
1. Furnace refractory bricks to accommodate heating coils for building
furnace floor/ bed with improved self life and for optimized uniform
heating of furnace comprising:
- a two part split assembly of bottom and top cover part, the bottom
part consisting of a base (01), two side walls (02), a divider (03)
dividing a gap between the side walls creating a multiple coil grooves
(04) running along the length of the brick side walls (02) to
accommodate heating coils (14), a stepped bearing surface (05)
provided on both top surfaces of the side walls, a lifting relief (06)
provided at the upper surface of a centrally cut mid-section of the side
walls to form slots (07) for converting and dissipating heat generated
by the heating coil;
- the top cover consisting of a central part (08) with two side flanges
(09) running along the length of the top part a lifting relief (10)
forming sloping passages to form a hollow cavity (12), a bottom

-16-
surface (11) provided below the flange sit over the bearing surfaces
(05) of the bottom part in matching relationship, convection flutes (13)
provided below the central part (08) communicating the hollow cavity
(12) via the coil grooves to the exterior furnace space to channel away
most of heat of coil by convection into the furnace thus enabling
optimized, uniform heat transfer of heating coil.
2. Furnace refractory bricks as claimed in claim 1 wherein the space below
bearing surface (05) forms a cylindrical or other preferred geometrical
space to receive cylindrically shaped heating coils.
3. Furnace refractory bricks as claimed in claims 1 and 2 wherein when a
furnace is heated by other means than that of heating coil, instrument
leads like thermocouples, pressure probes, potential probes etc. are
housed in the grooves (04) instead of heating coils.
4. Furnace refractory bricks as claimed in the preceding claims wherein the
said bricks are configured in geometrical shapes such as parallelogram,
cubic, cylindrical, ellipsoidal or other geometrical form used for building
floor of a typical furnace.

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5. Furnace refractory bricks as claimed in claim 1 wherein in the said bricks
multiple dividers (08) are constructed to provide multiple groves (04) in
the brick assembly.
6. Furnace refractory bricks as claimed in the preceding claims wherein the
furnace walls formed with the said bricks enable easy maintenance by not
allowing any scales from the heat treated jobs on the heating elements,
easy replacement of failed bottom brick without disturbing the rest
furnace walls, easy installation and inspection of heating coil by opening
the top part of the refractory brick assembly.
7. A method of producing furnace refractory bricks to accommodate heating
coils for building furnace floor / bed with improved self life and optimized
uniform heating of furnace comprising the steps of preparing refractory
brick concrete from refractory constituents, crushed fire bricks and
bounding agents on mixing and casting the mix into two separate split
part assembly in two preformed moulds and curving the cast two parts to
constitute a bottom part consisting of a base (01), two side walls (02) a
divided (03) dividing a gap between the side walls thus creating a multiple

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coil grooves (04) running along the length of the brick to accommodate
heating coils (14), a stepped bearing surface (05) provided on both top
surfaces of the side walls, a downward slopped lifting relief (06) provided
at the upper surface of a centrally cut mid-section of the side walls (02) to
from slots (07) for converting and dissipating heat generated by the
heating coil (14); a top cover part consisting of a central part (08) with
two side flanges (09) running along the length of the top part, a lifting
relief (10) forming a slopping passages to form a hollow cavity (12)
provided below the flange sit when put over the bearing surfaces (05) of
the bottom part, convection flutes (13) provided below the central part
(08) communicating with the hollow cavity (12) via the coil grooves (04)
to the exterior furnace space to channel away the heat of heating coil by
convection into the furnace to enable uniform heat transfer of heating
coil, when the said top part is placed over the bottom part and the
furnace walls when formed with mating brick assemblies are heated by
the coil (14) provided in the coil grooves (04) in the brick assemblies.
8. A method of producing furnace refractory bricks to accommodate heating
coils for building furnace floor / bed with improved self-life and for
optimized uniform heating of furnace as herein described.

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9. Furnace refractory bricks to accommodate heating coils for building
furnace floor/bed with improved self-life and for optimized uniform
heating of furnace as herein described and illustrated.
Dated this 26th day of March 2007.
This invention relates to a furnace refractory bricks to accommodate heating coils
for building furnace floor/ bed and a method of producing the bricks furnace
refractory bricks for building furnace floor / bed with improved self life and for
optimized uniform heating of furnace comprising: a two part split assembly of
bottom and top cover part, the bottom part consisting of a base (01), two side
walls (02), a divider (03) dividing a gap between the side walls creating a
multiple coil grooves (04) running along the length of the brick side walls (02) to
accommodate heating coils (14), a stepped bearing surface (05) provided on
both top surfaces of the side walls, a lifting relief (06) provided at the upper
surface of a centrally cut midsection of the side walls to form slots (07) for
converting and dissipating heat generated by the heating coil; the top cover
consisting of a central part (08) with two side flanges (09) running along the
length of the top part a lifting relief (10) forming sloping passages to form a
hollow cavity (12), a bottom surface (11) provided below the flange sit over the
stepped shape in bearing surfaces (05) of the bottom part in matching
relationship, convection flutes (13) provided below the central part (08)
communicating the hollow cavity (12) via the coil grooves to the exterior furnace
space to channel away most of heat of coil by convention into the furnace thus
enabling optimized, uniform heat transfer of heating coil.

Documents:

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Patent Number

251434

Indian Patent Application Number

469/KOL/2007

PG Journal Number

11/2012

Publication Date

16-Mar-2012

Grant Date

14-Mar-2012

Date of Filing

26-Mar-2007

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OPERATIONS DIVISION (ROD), PLOT NO : 9/1, DJBLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI- 110049

Inventors:

#	Inventor's Name	Inventor's Address
1	KAMALAKKANNAN, ISRAEL	HIGH PRESSURE BOILER PLANT BHARAT HEAVY ELECTRICALS LIMITED., TIRUCHIRAPALLI-620 014

PCT International Classification Number

C04B33/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA