FIELD OF INVENTION
The Present invention relates to oil burners. More particularly, the present invention
relates to oil burners employed in Circulating Fluidized Bed Combustion (CFBC) boilers.
BACKGROUND OF THE INVENTION
Oil burners are used in CFBC boilers. Bed material in the combustor of CFBC
boilers is heated by these burners upto auto ignition temperature of the solid fuel. As the
oil burners are used during the start-up of the CFBC boilers, the oil burners are
also called as start-up burners.
In CFBC boilers, oil burners are located in the side walls of the pant leg wall portion of the
combustor and are inclined (approximately 25°) downwards to heat the bed material during
the cold start-up of the boiler. As shown in fig. 1, the prior art oil burner includes primarily a
wind-box (1), on which, a guide sleeve (2), a guide pipe means (3), an Oil Gun means (4),
anlgnitor (5), a Flame scanner (6), and a retractor (7) with associated attachment
features are mounted. The Oil Gun means (4) slides inside the guide sleeve (2). The Oil Gun
means (4) is retracted/inserted with the aid of the pneumatically operated retractor (7).
When the burner is in operation, the Oil Gun means (4) is advanced into the combustor,
and Oil Gun means (4) is retracted away from the combustor, when the burner is not in
service. Advancing and retracting of the Oil Gun means (4) are accomplished through
Burner Management Logics.
As the Oil Gun means ( 4) has a spray plate with a plurality of miniature holes at its one
end, it is liable to be choked and is required to be cleaned very frequently. This is
accomplished by withdrawing Oil Gun means (4) out of the guide pipe means (3).
In order to heat the bed material, the burner is mounted inclined downwards such that
the burner flame faces the bed material. As per the prior art, the axis of the wind-box
(1), the guide sleeve (2), the guide pipe means (3) and Oil Gun means (4) are co-axial.
Hence, the burner axis is also invariably, inclined facing the combustor bed.
Accordingly, Oil Gun means (4) inside guide tube means (2&3) move along the axis of
flame propagation either during advance/retraction of Oil Gun means (4)
Consequently, withdrawal of the Oil Gun means (4) is feasible manually for maintenance
without using special handling tackles and accessing from the Burner-existing
platform is possible
The prior art of oil burner for CFBC boilers, is designed based on the "Sword and Sheath"
configuration.
The present invention thus provides a burner assembly suitable for inclined
withdrawal/insertion of Oil Gun means (4) in CFBC boilers, resulting in operational safety
and simplicity. The inventive burner assembly eliminates the possibility of interferences of
the burner components with buck-stays and other structural members of the boiler. The
invention allows modification of the existing burner assembly without a substantial physical
alteration in most of the components. The improved burner assembly enables an easy
accessibility of the burner including its accessories. The invention eliminates provision of
special tackles and additional platform, to withdraw/insert the Oil Gun means (4) assembly.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to propose an oil burner assembly for
CFBC boilers, which eliminates disadvantages of prior art withdrawal/replacement of Oil
Gun assembly inclined with respect to the burner floor.
Another object of the present invention is to propose an oil burner assembly for CFBC
boilers, which enables withdrawal/replacement of Oil Gun assembly inclined with
respect to the burner floor.
A still another object of the present invention is to propose an oil burner assembly for
CFBC boilers, which is provided with a modified wind box enabling orientation of
burner front plate maintaining the desired direction of flame propagation.
A further object of the present invention is to propose an oil burner assembly for CFBC
boilers, which enables an access from the burner floor itself.
A still further object of the present invention is to propose an oil burner assembly for
CFBC boilers, which eliminates provision of additional platform for withdrawal/replacement
of the Oil Gun means (4) of burner assembly .
Yet another object of the present invention is to propose an oil burner assembly for
CFBC boilers, which is simple to manufacture, manipulate and maintain.
SUMMARY OF INVENTION:
Accordingly, there is provided an improved Start-up Burner assembly with "Sword and
Sheath" configuration for circulating fluidized bed combustion (CFBC) boilers, comprising a
wind-box , a guide tube means , a guide sleeve means , Oil Gun means (4), an ignitor
, a flame Scanner , and a retractor , the improvement is characterized in that the guide
tube means comprises a bent pipe of uniform cross section with a guiding piece at
the bent end allowing a horizontal movement of the guide sleeve and in that a plurality of
stainless steel flexible hoses is provided on the atomizer means ,enabling a horizontal
withdrawal/removal of the atomizer means .
According to the present invention, unlike the sheath or a sword, the guide pipe means
includes a bent pipe of uniform cross section and a guiding piece, which enables a
horizontal withdrawal/removal of the Oil Gun means (4). Thus the Oil Gun means (4)
provided with stainless steel flexible hoses, is abled to freely move inside the guide sleeve. The shape of the
nozzle body in-built in the Oil Gun means (4) prevents the Oil Gun from getting stuck
during insertion/withdrawal. The front plate of the burner is modified so as to accommodate
the guide pipe, the guide sleeve and the Oil Gun means (4)
The Wind box provided having its front plate oriented perpendicular to the burner floor so
as to have an easy access to the oil gun, view ports and other accessories. Further, the
wind box is so arranged to ensure flame propagation to the desired direction and easy
mounting of the scanner and the ignitor.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure -1 : Prior art Burner assembly employed in CFBC boilers
Figure - 2 : Shows a Burner assembly for CFBC boilers according to the invention.
Figure - 3 : Shows a Wind-box with retractor arrangement according to the present
invention.
Figure - 4 : Shows a Guide Pipe means of the burner assembly according to the present
invention.
Figure - 5 : Shows a Guide sleeve means of the burner assembly as per the present
invention.
Figure - 6 : Shows an Oil Gun means of the burner assembly according to the present
invention
DETAILED DESCRIPTION OF THE INVENTION
As shown in figure-2, the oil burner assembly of the present invention include primarily a
wind-box (1), in which, a guide tube means with spinner (2), a guide sleeve means
(3), an Oil Gun means (4), an Ignitor (5), a Flame scanner (6), a retractor (7) and
other associated features are mounted. The Oil Gun means (4) slides inside the guide tube
means (2). The Oil Gun means (4) is retracted/advanced with the aid of the
pneumatically operated retractor (7). When the burner is in operation, the Oil Gun
means (4) is advanced into the combustor and when the burner is not in service, the Oil
Gun means (4) is retracted away from the
combustor. The Oil Gun means (4) is freely movable inside the guide sleeve means (3).
A plurality of seals are provided between the guide tube means (2) and the guide sleeve
means (3). An 'O' ring is provided on the Oil Gun means (4) which seals the interface
between the guide sleeve (3) and the atomizer means (4). Advancing and retracting of the
guide pipe means (2) are accomplished through the Burner Management Logics.
As shown in figure-3, n the wind-box assembly (1), a front plate (8) is placed oriented
perpendicular to the burner floor so as to allow an easy access to the oil gun, view
ports, and other accessories.
Further, the wind box (1) is so arranged to ensure the desired direction, flame
propagation to an easy mounting of the scanner (6) and ignitor (5). The guide pipe
means (2) is provided in the face plate (8) of the wind-box (1) in such a way that on
mounting of the burner, the axis of the guide pipe (2) is horizontal with respect to the
burner floor. A retractor (9) is mounted above the guide tube means (2).
As shown in figure-4, the guide tube means (2) has a bent (2a) and a straight portion
(2(b)). A conical piece (2a) is welded and the spinner (10) is mounted on the
conical piece (2a). The bent segment (2a) helps to locate the atomizer means (4)
inclined downwards. The Conical piece (2a) helps the atomizer means (4) to move
inside the guide pipe means (2) without getting stuck.
As shown in figure-5, the guide sleeve means (3) has a tube with a flange (11), a ball valve
(12) and a stationary union (13). One end of guide sleeve (2) is provided with
tapered inside to accommodate the smooth movement of the atomizer means (4).
As shown in figure-6, the Oil Gun means (4) has a nozzle body (14) and a spray plate (15)
attached to SS flexible hoses (16,17). Other ends of the SS hoses (16,17) are connected to
an oil pipe (18) and an air/steam pipe (19). The SS flexible hose (18,19) helps to align the
axis of flame propagation to the required inclination. On mounting of the burner, the
straight portion (2b) of the oil pipe (18) and air/steam pipe (19) are parallel to the burner
floor. This helps to withdraw the Oil Gun means (4), horizontally, accessing from the burner
floor.
As shown in figure-2, the burner assembly is mounted inclined downwards such that the
burner flame faces the bed material and heat the bed material. As per the invention, the
axis of the outlet of the wind-box (1), one end of guide tube means (2) and the Oil
Gun means (4) are in line with the axis of flame propagation. A substantial length of
the guide tube means (2) and the Oil Gun means (4) are parallel to the burner floor.
The guide sleeve (3) is also placed horizontal to the burner floor. The guide
sleeve (3) along with the Oil Gun means (4) can be advanced/retracted. Movement
of the Oil Gun means (4) and the guide sleeve (3) are along the burner floor. During
withdrawal/replacement of the Oil Gun means (4) ,the end of the Oil Gun means (4) is
accessible from the burner floor, through out its entire withdrawal.

WE CLAIM ;
1. An improved Start-up Burner assembly with "sword and sheath" configuration for
circulating fluidized bed combustion (CFBC) boilers, comprising
a wind-box (1), a guide tube means (2), a guide sleeve means (3),
an Oil Gun means (4) ,an ignitor (5), a flame Scanner (6), and a retractor (7), the
improvement is characterized in that the guide tube means (2) comprises a bent pipe
(2b) of uniform cross section with a guiding piece (2a) at the bent end allowing a
horizontal movement of the guide sleeve (3),and in that a plurality of stainless steel
flexible hoses (18,19) is provided on the Oil Gun means (4),enabling a horizontal
withdrawal/removal of the Oil Gun means (4).
2) The burner assembly as claimed in claim-1 wherein the Wind box (1) is provided
with a front plate (8) oriented perpendicular to the burner floor enabling an easy access to
the oil gun, view ports and other accessories.
3. The burner assembly as claimed in claim 1, wherein a bent guide tube is provided.
4) The burner assembly as claimed in claim-3, wherein a curved segment 2(a) is provided
with a long radius of curvature corresponding to the burner orientation of the CFBC boiler.
5) The burner assembly as claimed in claim-3, wherein the guide tube means (2) is
located below the centre axis of the wind-box (1).
6) The burner assembly as claimed in claim-1 wherein the retractor (7) is mounted
above the guide pipe (2) on the wind box (1).
7) The burner assembly as claimed in claim-3 wherein the guide pipe means (2) is
provided with a guide piece (2b) for locating appropriately a spray plate (15), of the
Oil Gun means (4)
8) The burner assembly as claimed in claim-7, wherein a conical inner plate (2a) enables
a smooth gliding of the spray plate/nozzle body (15,14) inside the guide pipe means (2)
and to ensure an exact location of the spray plate (15) inside the burner.
9) The burner assembly as claimed in claim-1 wherein the guide sleeve (3)
comprises a ball valve (12) and a stationary union (13).
10) The burner assembly as claimed in claim-1 wherein the Oil Gun means (4)
comprises a nozzle body (4).
11) The burner assembly as claimed in claim-10 wherein the nozzle body (14) has a
tapered end, and wherein a broader end of the nozzle body (14) is welded to a SS flexible
hose (18,19) to allow the Oil Gun means (4) to move without getting stuck inside the guide
pipe (2).
12. The burner assembly as claimed in claim 1, wherein the axis of the outlet of the wind
box (1), a first end of the guide tube means (2), and Oil Gun means (4) are coaxial with the
axis of flame propagation.
13. The burner assembly as claimed in claim 12, wherein a substantial length of the guide
tube means (2), the guide sleeve (3) and the Oil Gun means (4) are parallel to the burner
floor.
14. An improved Start-up Burner assembly with "sword and sheath" configuration for
circulating fluidized bed combustion (CFBC) boilers as substantially described and illustrated
herein with reference to the accompanying drawings.

The invention relates to an improved Start-up Burner assembly with "sword and sheath"
configuration for circulating fluidized bed combustion (CFBC) boilers, comprising a wind-
box (1), a guide tube means (2), a guide sleeve means (3), an Oil Gun means (4), an
ignitor (5), a flame Scanner (6), and a retractor (7). The guide tube means (2)
comprises a bent pipe (2b) of uniform cross section with a guiding piece (2a) at the bent
end allowing a horizontal movement of the guide sleeve (3),and in that a plurality of
stainless steel flexible hoses (18,19) is provided on the atomizer means (4),enabling a
horizontal withdrawal/removal of Oil Gun means (4).