FIELD OF THE INVENTION
The present invention relates to a gas fired burner system for tundish preheating. More
particularly, the present invention is directed to an improved gas fired burner system having
a plurality of fin like swirlers in gas and air lines in order to anchor the flame and provide
sufficient mixing between gas and air wherein the gas is made to swirl at an angle more
than that of air and a method of preheating the inside surface of tundish before pouring
molten steel through the tundish into continuous casting machine, ensuring desired flame
profile and uniform heating pattern of tundish and enhanced burner life. The improved
burner according to this invention is used for preheating the tundish for continuous casting
process by advantageous and efficient burning with a bushy, swirling type flame adapted to
heat the remotest corners of tundish with equal efficiency through top mounted gas fired
burner system and thus favouring desired stopper rod movements to regulate/stop liquid
metal flow from tundish, reducing the requirement of melt temperature in ladle before
casting, avoiding rapid drop in temperature during casting and thus favouring continuous
casting operation with improved quality, less rejection and reduced cost of operation. The
gas fired burner system according to the present invention is thus having prospects for wide
scale use in steel plants/continuous casting plants with economy in energy efficient manner
and improved productivity.
BACKGROUND ART
Tundishes are required to be preheated to a temperature above 1000°C throughout its
inside surfaces before pouring steel into it, in the continuous casting operation. Improper
preheating of tundishes lining surfaces lead to higher liquid steel temperature drop as it is
poured into the tundish during casting causing unwanted heat loss and poor energy
efficiency. This necessitate requirement of maintaining higher molten metal temperature in
the ladle. Further, improper preheating of the stopper rod which is the part of a tundish for
regulating/stopping liquid steel flow from the tundish to mould, poses problems in proper
stopper rod movement which results in wastage/rejection of casting due to poor
quality/casting defects caused by stopper rod failure. Proper tundish preheating is more
important for adopting flying tundish practice, where tundish will be always in completely
heated condition ready for casting.

It is well known in the art of steel casting processes, gas-fired burners are often used for
preheating the tundish. As the tundish depth is very less, short flame is required to be
generated by the tundish preheating burners. A conventional burner achieves short flame
length through cast burner head with diffuser, whose life is considerably less as it has a
large area exposed to intense heat. Once the burner head gets damaged, the burner
performance gets affected. It has been found that the life of the burner made of SS is very
less during the normal use of tundish preheating. Another drawback is that once the burner
head is damaged due to overheating, the flame configuration gets changed, resulting in
unsatisfactory flame profile and heating pattern. Yet another drawback of the conventional
gas burner based tundish heating systems is that the burners are required to be made with
higher heat resisting material, like inconel, which would increase the cost considerably.
Moreover, the conventional burner design is not energy efficient and economical.
There has been, therefore, a need in the art to develop a gas based burner system for
tundish preheating which would eliminate the problems and limitations experienced in the
prior art and enable providing means for efficient and economic means for tundish
preheating. The burner system would be developed to have improved configuration to
economize fuel gas consumption, ensure desired flame characteristics and pattern of heat
distribution favouring uniform heating of the inner lining of tundish up to any remote corner
location, protect the burner head from over heating and damage, proper stopper movement
for metal flow from tundish, thereby, improving quality and yield of casting process and also
enhancing the burner life.
OBJECTS OF THE INVENTION
The basic object of the present invention is thus directed to developing a gas fired burner
system for tundish preheating ensuring uniform tundish heating in energy efficient manner,
enhancing the burner life and improving casting quality.
Another object of the present invention is directed to developing a gas fired burner system
for tundish preheating ensuring uniform tundish heating wherein the burner system has the
configuration to ensure proper mixing of the air and the gas flow to generate desired flame
characteristics and heat distribution pattern for uniform tundish heating to reduce drop in
temperature of liquid metal during pouring.

A further object of the present invention is directed to developing a gas fired burner system
for tundish preheating adapted to ensure longer burner life by protecting the burner head
against overheating and damage.
A further object of the present invention is directed to developing a gas fired burner system
for tundish preheating wherein a plurality of fin like swirlers in gas and air lines are provided
in order to provide sufficient mixing between gas and air resulting in anchoring of the flame.
A still further object of the present invention is directed to developing a gas fired burner
system for tundish preheating wherein the gas is made to swirl at an angle more than that
of air, depending on the tundish dimensions, gas pressure and air pressures, that change
from one application to another, so that the burner design is modified to distribute gas and
air accordingly.
A still further object of the present invention is directed to developing a gas fired burner
system for tundish preheating wherein said system provides efficient burning with a bushy
swirling type flame adapted to heat the remotest corners of tundish with equal efficiency
through top mounted gas fired burner system.
A still further object of the present invention is directed to developing a gas fired burner
system for tundish preheating wherein uniform heating of tundish helps eliminating the
problems of stopper rod movement during continuous casting so as to ensure desired
regulating/stopping liquid steel flow from tundish.
A still further object of the present invention is directed to developing a gas fired burner
system for tundish preheating wherein uniform heating of tundish favours flying tundish
practice, so that tundish will be always in completely heated condition ready for casting.
A still further object of the present invention is directed to developing a gas fired burner
system for tundish preheating wherein said system is simple, energy efficient, less
expensive, reliable and adapted for enhanced life of burner in continuous casting operation.

SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to developing a gas-fired burner
system adapted for uniform preheating of tundish comprising atleast one burner having a
central dummy tube adapted for supporting gas swirlers, a concentric outer gas tube with
air swirlers on the outer side, for supplying gas and another outer concentric air tube for
supplying air such as to achive said desired uniform preheating of the tundish.
A further aspect of the present invention is directed to developing a gas-fired burner system
wherein in order to anchor the flame and provide sufficient mixing between gas and air, the
gas is made to swirl at an angle more than that of air.
A still further aspect of the present invention is directed to developing a gas-fired burner
system wherein based on the tundish dimensions, gas pressure and air pressures from one
application to another, the said burner is adapted for selective modification to distribute
gas and air accordingly.
A still further aspect of the present invention is directed to a gas-fired burner system
wherein the head of the burner is provided with a co-axially disposed cylindrical gas tube for
supplying gas for combustion which is adapted to fit around the fin-like gas swirlers.
A still further aspect of the present invention is directed to a gas-fired burner system
wherein the head of the burner has a co-axially disposed cylindrical gas tube surrounded by
a set of fin-like air swirlers.
According to yet another aspect of the present invention is directed to a gas-fired burner
system wherein the heat transfer rate from the hot burner head exposed to intense heat is
increased with the incoming cold gas and air taking part in combustion with the help of the
increased surface area of fin-like gas and air swirlers.
A still further aspect of the present invention is directed to a gas-fired burner system
wherein the head of the burner has a co-axially disposed cylindrical air tube adapted for
supplying air for combustion which fits around the air swirlers.

According to an important aspect of the present invention is directed to a gas-fired burner
system adapted such that the flame generated impinges upon the farthest corners of the
tundish thereby providing the heat required to the remote corners of the tundish.
Also, said gas-fired burner system is adapted for preheating tundish which can be used for
pouring molten metal into a mould for casting without splashing.
A still further aspect of the present invention is directed to a method of uniform preheating
of tundish comprising using the burner system.
The present invention and its objects and advantages are described in greater details with
particular reference to the following non limiting accompanying figure.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 : is the schematic illustration of the cross section of the improved gas fired burner
system of the present invention showing disposition of different components, flow passages
for gas/air and the selective orientation of gas/air swirlers.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS
The present invention relates to an improved gas fired burner system having a plurality of
fin like swirlers in gas and air lines and a method of preheating the inside lining surface of
tundish before pouring molten steel through the tundish into continuous casting machine.
The burner system generates bushy swirling type thurst flame adapted to heat the tundish
uniformly while the flame profile is able to reach the most remote corner of the tundish
lining.
Reference is invited to the accompanying Figure 1 that schematically illustrates cross
sectional view of the improved gas fired burner system of the present invention showing
disposition of different components, flow passages for gas/air and the selective orientation
of gas/air swirlers.

The improved gas fired burner system of the invention having its configuration comprising
of a vertical cylindrical dummy tube being surrounded by a set of fin-like gas swirlers; a co-
axially disposed vertical cylindrical gas tube being surrounded by a set of fin-like air
swirlers; the gas tube fits around the said dummy tube and gas swirlers for supplying gas
through the gas swirlers and another co-axially disposed vertical cylindrical air tube around
the said gas tube for supplying air through the air swirlers. The swirlers are so inclined,
preferably in the range of 10 to 45 degrees for air and 15 to 60 degrees for gas, so as to
ensure proper and thorough mixing of the air with gas and generate a bushy, properly
anchored high thrust flame commensurate with tundish dimensions, air and gas pressure
thereby reaching the most remote corner of inner lining surface of tundish.
The accompanying Figure 1 shows the cross section of an improved gas fired burner of the
invention. Referring to the drawing, it can be seen that each burner consists of a central
dummy tube (1) for supporting gas swirlers (4), a concentric outer gas tube (2) with air
swirlers (5) on the outer side, for supplying gas and another outer concentric air tube (3),
for supplying air. In order to anchor the flame and provide sufficient mixing between gas
and air, the gas is made to swirl at an angle more than that of air. If the tundish
dimensions, gas pressure and air pressures change from one application to another, the
burner design can be modified to distribute gas and air accordingly.
It is thus possible by way of the present invention to provide a gas fired burner system for
preheating of tundish wherein said burner system creates a short, bushy, high thrust flame
where the flame and combustion products spread to the farthest corner of the inside lining
of the tundish, thereby releasing the heat of combustion at a further away point. The burner
system also increases the heat transfer rate from the hot burner head which is exposed to
intense heat to the incoming cold gas and air taking part in combustion, with the help of the
increased surface area of fin-like swirlers.
Advantageously, the burner configuration according to the present invention is adapted to
provide uniform tundish preheating to a temperature above 1000 °C within 3 hours and
increased burner head life to more than 10 years, making such system capable of wide
industrial application in steel plants for continuous steel casting operation.

We Claim:
1. A gas-fired burner system adapted for uniform preheating of tundish comprising
atleast one burner having a central dummy tube adapted for supporting gas
swirlers, a concentric outer gas tube with air swirlers on the outer side, for
supplying gas and another outer concentric air tube for supplying air such as to
achieve said desired uniform preheating of the tundish.
2. A gas-fired burner system as claimed in claim 1 wherein in order to anchor the
flame and provide sufficient mixing between gas and air, the gas is made to swirl
at an angle more than that of air.
3. A gas-fired burner system as claimed in anyone of claims 1 or 2 wherein based
on the tundish dimensions, gas pressure and air pressures from one application
to another, the said burner is adapted for selective modification to distribute
gas and air accordingly.
4. A gas-fired burner system as claimed in anyone of claims 1 to 3 wherein the
head of the burner is provided with a co-axially disposed cylindrical gas tube for
supplying gas for combustion which is adapted to fit around the gas swirlers.
5. A gas-fired burner system as claimed in anyone of claims 1 to 4 wherein the
head of the burner has a co-axially disposed cylindrical gas tube surrounded by a
set of fin-like swirlers.
6. A gas-fired burner system as claimed in anyone of claims 1 to 5 wherein the
heat transfer rate from the hot burner head exposed to intense heat is increased
with the incoming cold gas and air taking part in combustion with the help of the
increased surface area of fin-like swirlers.
7. A gas-fired burner system as claimed in anyone of claims 1 to 6 wherein the
head of the burner has a co-axially disposed cylindrical air tube adapted for
supplying air for combustion which fits around the air swirlers.

8. A gas-fired burner system as claimed in anyone of claims 1 to 7 adapted such
that the flame generated impinges upon the farthest corners of the tundish
thereby providing the heat required to the remote corners of the tundish.
9. A gas-fired burner system as claimed in anyone of claims 1 to 8 adapted for
preheating tundish, which is used for pouring molten metal into a mould for
casting without splashing.
10. A method of uniform preheating of tundish comprising using the burner system
as claimed in anyone of claims 1 to 9.
11. A gas-fired burner system substantially as herein described and illustrated with
reference to the accompanying figures.

The present invention relates to an improved gas fired burner system having a plurality of
fin like swirlers in gas and air lines in order to anchor the flame and provide sufficient
mixing between gas and air wherein the gas is made to swirl at an angle more than that of
air for desired uniform preheating of the inside lining surface of tundish, before pouring
molten steel with enhanced burner life. The gas-fired burner of the invention is used for
energy efficient preheating of the tundish with a bushy, swirling type anchored flame
adapted to heat the remotest corners of tundish with equal efficiency avoiding rapid drop in
temperature during casting and thus favouring continuous casting operation with improved
quality, less rejection and reduced cost of operation. The gas fired burner system according
to the present invention is thus having prospects for wide scale use in steel plants /
continuous casting plants with economy in energy efficient manner and improved
productivity.