DESC:FIELD OF THE INVENTION

The present disclosure generally relates to burner systems, and more particularly, to fuel efficient burner system and an associated method for outside vapor deposition of silica soot for manufacturing optic fibers.

BACKGROUND

Optic fiber manufacturers produce high purity silica glass having high refractive index homogeneity using silica soot deposition using the Outside Vapor Deposition (OVD) technique among other techniques. Silica (SiO2) ingots are synthesized using silicon tetrachloride (SiCl4) over oxy-hydrogen diffusion flames using a series of kinetic reactions and subsequent cooling.

Conventional burner system includes one or more oxy-hydrogen burners having central axes oriented vertically. Each burner includes a plurality of slits or orifices arranged in concentric circular pattern. Reactants such as but not limited to Silicon tetrachloride (SiCl4), oxygen, hydrogen, inert gases, and doping chemicals such as but not limited to germanium tetrachloride (GeCl4) are fed into the burners through relevant supply lines. The SiCl4 reacts with the oxygen and hydrogen to form silica (SiO2) and hydrochloric acid vapours (HCl).

The silica soot generated from the reactions travels upwards from where the silica soot is deposited on a horizontally oriented spindle. The spindle is rotated about an axis and actuated along a longitudinal direction for deposition of silica soot along the spindle. The exhaust gases including unreacted gases, products from reactions, and un-deposited silica exit through an exhaust unit located above the burners.

After the required silica preform diameter is reached, the burners are switched off and the spindle is removed. The silica preform is then dried and sintered in a furnace maintained at a temperature of approximately 1400–1600 degrees Celsius, before the preform is processed further to produce optical fibers.

One drawback associated with the conventional burner system is that only about 40-70% of the silica soot gets deposited on the spindle while rest of the silica soot escapes through the exhaust unit leading to low soot deposition efficiency. Moreover, the silica soot also escapes past the spindle especially early on during the deposition process when the workpiece diameter is small.

Another drawback is that the silica soot particles are generated with a radial density gradient in an outward direction from a center of the cylindrical burner. Silica soot is deposited onto the spindle in a spiral pattern due to the actuation of the spindle along a longitudinal direction and simultaneous rotation about a central axis. However, due to the spiral deposition pattern, portions having a high soot density are overlapped at certain positions of the spindle. Thus, the overlapped portions of the spindle become relatively thicker. This causes unevenness of the preform, thereby undermining quality. Such unevenness causes ripples on the outer circumference of a finished optical fiber preform after the sintering process. The ripples formed on the surface of the optical fiber preform affects frequency-blocking characteristics and the distribution characteristics that are sensitive to the core diameter. In addition, rapid actuation of the spindle (or the burner) may cause turbulence to a laminar flow characteristic of the flame. So, there is a limit to the spiral pattern pitch which can be generated, to minimize the unevenness.

Yet another drawback is that since the spindle is actuated, both ends of the silica ingot have lower amounts of silica soot deposits. Hence, the silica ingots are conical shaped at either ends. The cone-shaped portions must be discarded resulting in wastage/additional losses.
There is a need for an enhanced burner system and an associated method for outside vapor deposition of silica soot that overcomes at least the drawbacks discussed herein.

SUMMARY
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.

The present disclosure relates to a fuel-efficient burner system for outside vapor deposition of silica soot. The system as disclosed herein provides a plurality of burner modules that focuses concentrated flames to a central axis of a spindle rotating at an axis longitudinal to the plurality of burner modules.

Embodiments of the present disclosure provides a fuel-efficient burner system for outside vapor deposition of silica soot. The system comprises a plurality of burner modules having a plurality of slits to outflow reactant gas, the plurality of burner modules includes a recessed portion and supported by a pair of inclined walls at extreme ends. The system comprises a spindle aligned along a longitudinal direction parallel and placed over the plurality of burner modules, wherein the spindle is supported by rods at extreme ends. The system comprises a hood surrounding the plurality of burner modules to enable a focus of the plurality of slits to a central axis of the spindle, the hood is a dome shaped structure having covered from sides, open at a top narrow at a distal end, and mounted on the base plate. The system comprises a base plate coupled to a bottom of the plurality of burner modules and the hood.

Briefly, according to an exemplary embodiment, streams of oxygen, hydrogen, silicon tetrachloride, and any other chemicals are focused onto a focal line, namely the central axis of the spindle. As a result, percentage of silica soot which does not contact the spindle and going out as exhaust would be minimized.

The exemplary burner system facilitates in maintaining a good thermal gradient between the workpiece surface and the silica soot particles to enhance silica soot deposition efficiency due to thermophoresis.

In one embodiment, uniform feed of the reactants mentioned herein along the entire length of the spindle, facilitates in eliminating the need for actuation of the spindle, resulting in uniform deposition of the silica soot and minimization of the conical formation of soot particles at ends of the preform.

To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
FIG. 1 [PRIOR ART] illustrates a schematic representation of a conventional burner system;
FIG. 2 [PRIOR ART] illustrates a schematic representation of a conventional burner and a spindle;
FIG. 3 illustrates a schematic isometric view of a fuel-efficient burner system, in accordance with an embodiment of the present disclosure;
FIG. 4 illustrates a illustrates a schematic side view of the fuel-efficient burner system in accordance with an embodiment of FIG. 3 of the present disclosure;
FIG. 5 illustrates a illustrates a schematic isometric view of the fuel-efficient burner system in accordance with an embodiment of FIG. 3 of the present disclosure;
FIG. 6 illustrates a schematic isometric view of the fuel-efficient burner system without burner module(s) and cooling fan in accordance with an embodiment of FIG. 3 of the present disclosure;
FIG. 7 illustrates a schematic isometric view of the burner module in accordance with an exemplary embodiment of the present disclosure;
FIG. 8 illustrates a schematic cross-sectional view of a top portion of the burner module in accordance with an exemplary embodiment of FIG. 7 of the present disclosure;
FIG. 9 illustrates a schematic isometric view of a base plate of the burner module in accordance with an exemplary embodiment of FIG. 7 of the present disclosure;
FIG. 10 illustrates a schematic isometric view of a gas header coupled to the base plate of the burner module in accordance with an exemplary embodiment of FIG. 9 of the present disclosure;
FIG. 11 illustrates a schematic side view of the gas header coupled to the base plate of the burner module in accordance with an exemplary embodiment of FIG. 10 of the present disclosure;
FIG. 12 illustrates a schematic bottom isometric view of the gas header coupled to the base plate of the burner module in accordance with an exemplary embodiment of FIG. 10 of the present disclosure;
FIG. 13 illustrates a schematic isometric view of the cooling fan in accordance with an exemplary embodiment of the present disclosure;
FIG. 14 illustrates a schematic side view of the cooling fan in accordance with an exemplary embodiment of the present disclosure; and
FIG. 15 illustrates a flow chart of a method for outside vapor deposition of silica soot, in accordance with an embodiment of the present disclosure.

Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION OF FIGURES

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which invention belongs. The system and examples provided herein are illustrative only and not intended to be limiting.

For example, the term “some” as used herein may be understood as “none” or “one” or “more than one” or “all.” Therefore, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would fall under the definition of “some.” It should be appreciated by a person skilled in the art that the terminology and structure employed herein is for describing, teaching, and illuminating some embodiments and their specific features and elements and therefore, should not be construed to limit, restrict or reduce the spirit and scope of the present disclosure in any way.

For example, any terms used herein such as, “includes,” “comprises,” “has,” “consists,” and similar grammatical variants do not specify an exact limitation or restriction, and certainly do not exclude the possible addition of one or more features or elements, unless otherwise stated. Further, such terms must not be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated, for example, by using the limiting language including, but not limited to, “must comprise” or “needs to include.”
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Whether or not a certain feature or element was limited to being used only once, it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do not preclude there being none of that feature or element, unless otherwise specified by limiting language including, but not limited to, “there needs to be one or more...” or “one or more elements is required.”

Unless otherwise defined, all terms and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by a person ordinarily skilled in the art.

Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements of the present disclosure. Some embodiments have been described for the purpose of explaining one or more of the potential ways in which the specific features and/or elements of the proposed disclosure fulfil the requirements of uniqueness, utility, and non-obviousness.

Use of the phrases and/or terms including, but not limited to, “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or other variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

Any particular and all details set forth herein are used in the context of some embodiments and therefore should not necessarily be taken as limiting factors to the proposed disclosure.

In an embodiment of the present disclosure, a tracking system for a solar energy collector is disclosed. The tracking system enables simultaneous adjustment of the altitude angle and the azimuth angle of the solar energy collector based on the movement of the sun in the sky to maximize solar energy reception.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

For the sake of clarity, the first digit of a reference numeral of each component of the present disclosure is indicative of the Figure number, in which the corresponding component is shown. For example, reference numerals starting with digit “1” are shown at least in Figure 1. Similarly, reference numerals starting with digit “2” are shown at least in Figure 2.

FIG. 1 [PRIOR ART] illustrates a schematic representation of a conventional burner system 10. The burner system 10 includes one or more oxy-hydrogen burners 12 having central axes oriented vertically. The burner(s) includes orifices 14 arranged in concentric circular patterns. Silicon tetrachloride (SiCl4), oxygen, hydrogen, inert gases, and doping chemicals such as germanium tetrachloride (GeCl4) are fed into the burner(s) through relevant supply lines. The SiCl4 reacts with the oxygen and hydrogen to form silica (SiO2) and hydrochloric acid vapors (HCl).

The silica soot generated from the burner(s) 12 travels upwards from where the silica soot is deposited onto a horizontally oriented spindle 16. The spindle 16 is rotated about an axis and actuated in the longitudinal direction for deposition of silica soot along the spindle 16.

FIG. 2 [PRIOR ART] illustrates a schematic representation of a conventional burner 12 and a spindle 16. Silica soot particles are generated with a radial density gradient in an outward direction from a center of the burner 12. Silica soot is deposited on the spindle 16 to form a spiral pattern along a longitudinal direction due to the actuation of the spindle 16 and simultaneous rotation about a central axis. Since the spindle 16 is actuated, both ends of the silica ingot have lower amounts of silica soot deposits. Hence, the silica ingots are conical shaped at either ends.

FIG. 3 illustrates a schematic illustration of a perspective view of an exemplary burner system 20 in accordance with an embodiment of the present disclosure. The fuel-efficient burner system 20 includes a plurality of burner modules 21 having a plurality of slits 28, a spindle 22, a hood 24, and a base plate 40. The burner system 20 includes a plurality of interlocked burner modules 21 aligned along a longitudinal direction parallel to a spindle 22. The plurality of interlocked burner modules 21 are arranged along a substantial length of the spindle 22. Each burner module 21 includes a plurality of slits and/or orifices for exit of the reactants. A distance between the burner modules 21 and the spindle 22 is set such that the slits and/or orifices are positioned focused towards the central axis of the spindle 22. A hood 24 surrounds the burner modules 21 such that inclined walls of the hood 24 are directed towards the central axis of the spindle 22. In the illustrated embodiment, a cooling fan 26, for example, a V-shaped fan is disposed extending in the longitudinal direction of the spindle 22.

According to an embodiment, the fuel-efficient burner system 20 comprises the plurality of burner modules 21 having a plurality of slits 28 to outflow reactant gas. The plurality of burner modules 21 includes a recessed portion 32 and supported by a pair of inclined walls at extreme ends. The term “fuel-efficient burner system” as used herein refers to burners heaters, and/or cookers that are configured to heat workpieces or containers to perform cooking, baking and/or heating. The plurality of burner modules 21 includes the recessed portion 32 having the plurality of slits 28 to outflow the reactant gas.

FIG. 4 illustrates a schematic side view of the fuel-efficient burner system 20 in accordance with an embodiment of FIG. 3 of the present disclosure. The fuel-efficient burner system 20 includes a spindle 22 aligned along a longitudinal direction parallel and placed over the plurality of burner modules 21. The spindle 22 is supported by rods at extreme ends. The rods may include but not limited to ceramic rods. The burner system 20 includes a plurality of interlocked burner modules 21 aligned along a longitudinal direction parallel to the spindle 22 (shown in FIG. 3). Each burner module 21 includes the plurality of slits and/or orifices formed along a plurality of inclined walls. The hood 24 surrounds the burner modules 21 such that inclined end walls of the hood 24 are directed towards the central axis of the spindle 22. In the illustrated embodiment, the cooling fan 26 is disposed extending along the longitudinal direction of the spindle 22.

FIG. 5 illustrates a schematic perspective view of the exemplary burner system 20 in accordance with an embodiment of FIG. 3 of the present disclosure. Each burner module 21 includes the plurality of slits 28 for exit of reactants.
The reactants eventually egress from the slits 28. Thereafter, these reactants react to form silica nano-particles that are deposited onto the spindle 22. In another embodiment, instead of a plurality of burner modules 21 disposed along the entire length of the spindle 22, only a single burner module 21 or a small number of burner modules 21 may be utilized. In such an embodiment, the spindle 22 would actuate along the longitudinal direction in addition to rotational motion about a longitudinal axis. Also, in such an embodiment, much broader spiral patterns of silica soot deposition would form on the spindle 22 which would solve the problem of uneven deposition to a large extent. The hood 24 is not shown. It also be noted herein that shapes, number, and dimensions of orifices and slits may vary depending on the application. The angle of inclination of the slits and/or orifices may vary depending on the application. The dimensions of the burner modules 21 may also vary depending on the application.

One consideration for silica soot deposition is that the silica soot deposition efficiency significantly depends on the thermophoretic effect caused by the thermal gradient between the hot silica soot particles and the cooler workpiece surface. Therefore, to facilitate silica soot deposition, having a cooler workpiece surface is necessary.

In one embodiment of the present disclosure, there is no actuation of the spindle 22 along a longitudinal direction, and hence the cooling time for all portions of the workpiece are dependent only on the rotation speed of the spindle 22. In accordance with the exemplary embodiment of the present disclosure, the heat from the burner module(s) 21 is spread over a larger area of the workpiece, causing much lesser increase of the temperature of the workpiece. Nevertheless, the workpiece surface may need to be cooled down to maintain acceptable preform properties and a good silica soot deposition rate.

To rapidly cool the workpiece to a desired temperature, the burner module(s) 21 is shut down and pressurized air at room temperature is blown to the entire length of the workpiece by the cooling fan 26. The cooling slab of air is laminar in nature, thereby enabling to cool down the workpiece uniformly via convection. The spindle 22 is rotated to ensure uniform cooling. The burner module(s) 21 is shut down only after a certain number of rotations of the spindle 22 to ensure uniform deposition the silica soot to the spindle 22. After cooling operation is completed, the burner(s) module 21 is restarted by an automatic spark ignition unit. The deposition and cooling cycles continue till the desired workpiece diameter is obtained. In some embodiments, a control system is used to govern motions of the spindle 22 and the operation of burner valves and the spark ignition unit.

FIG. 6 illustrates a schematic perspective view of the exemplary burner system 20 in accordance with an embodiment of FIG. 3 of the present disclosure. In the illustrated embodiment, the burner module(s) 21 and the cooling fan 26 are not shown. The hood 24 (made of glass or stainless steel, for example) is disposed surrounding the burner module(s) 21. The longer sides of the hood 24 converge towards the central axis of the spindle 22. The hood height is set so that a top end of the hood 24 is positioned at a predefined distance, for example, 25-30 mm away from the maximum circumference of the workpiece. The hood height may be adjusted/varies to ensure that silica soot does not deposit onto hood walls. The purpose of the hood 24 is to further direct the burner reactants towards the central axis of the spindle 22 to improve the deposition efficiency. The hood 24 ensures that the reactants that egress from the burner module(s) 21 do not diffuse into surroundings away from the burner flame.

FIG. 7 illustrates a schematic perspective view of the burner module 21 in accordance with an exemplary embodiment of the present disclosure. In the illustrated embodiment, the burner module 21 includes a plurality of slits 28 formed for exit of reactants. Further, in the illustrated embodiment, the burner module 21 includes slits 28 also formed in a recessed portion 32 formed between the inclined end walls 30. In some embodiments, orifices may be used instead of slits. In other embodiments, combination of slits 28 and orifices may be used. In one embodiment, the burner module 21 may have a trapezoidal shape cross section.

FIG. 8 illustrates a schematic cross-sectional view of a top portion 34 of the burner module 21 in accordance with an exemplary embodiment of FIG. 7 of the present disclosure. The top portion 34 includes the plurality of slits 28 formed along a plurality of inclined end walls 30. Further, in the illustrated embodiment, the burner module 21 includes slits 28 formed in the recessed portion 32 between the inclined end walls 30. The top portion 34 includes a plurality of channels 36 and plates 38, where each channel 36 is formed between a pair of plates 38. Each channel 36 is fluidically coupled to the corresponding slit 28. The number of channels 36, slits, and/or orifices may vary depending on the application.

The slits 28 are directed towards a central axis of the spindle. The inner slits 28 maybe offset downward by a distance ‘l’. This difference in height ensures that the silicon tetrachloride and silica soot have a longer distance to travel to reach the spindle. Therefore, the longer travel time ensures that the silicon tetrachloride can react completely and also possibly yield large silica soot particles. It should be noted herein that larger size silica soot particles have more momentum and are therefore more likely to deposit on the workpiece. Such an arrangement enables to generate an inner flame inside an outer flame. In one embodiment, the distance “l” is but not limited to 60 mm. In one embodiment, the burner module 21 may have a trapezoidal shape cross-section without any recession of the inner slits instead of the configuration shown in FIG. 8.

FIG. 9 illustrates a schematic isometric view of a base plate 40 of the burner module 21 in accordance with an exemplary embodiment of FIG. 7 of the present disclosure.
The base plate 40 includes a plurality of projections coupled to a plurality of grooves at a base of the plurality of burner modules 21. The base plate 40 is a corrugated plate having projections 42 that are inserted into matching grooves formed on the bottom surface of the top portion 34 (shown in FIG. 8). Such a coupling enables the top portion 34 and the base plate 40 to fit tightly and to prevent gas leakage and mixing between individual compartments of the burner module 21. The base plate 40 also includes bolt holes 44 for securing the top portion 34 and base plate 40 together. The base plate 40 also includes additional holes for enabling connection of the gas supply lines/header. The base plate 40 also includes shoulder portions on which wire mesh cassettes of 50 to 150 microns size, for example, can fit in each of gas chambers to enhance diffusion of the incoming reactants from a gas header uniformly along the length of the burner module 21. The provision of wire mesh cassettes ensures that flow rate of reactants along the length of the burner module 21 is homogeneous to ensure homogeneous silica soot deposition onto the spindle. In some embodiments, perforated plates may be used instead of the wire mesh cassettes/inserts. The base plate 40 also includes gas inlet holes 41, corresponding to the gas channels 36 on the burner top portion. These inlet holes are provided with threaded or welded fittings that help connect the gas supply hoses to the burner base plate 40.

FIG. 10 illustrates a schematic isometric view of a gas header 46 coupled to the base plate 40 of the burner module 21 having in accordance with an exemplary embodiment of FIG. 9 of the present disclosure. The gas header 46 includes a plurality of tubes (for example, square tubes) 48 having blind flanges at both ends. The gas header 46 may be made of aluminium or mild steel, for example.

FIG. 11 illustrates a schematic side view of the gas header 46 coupled to the base plate 40 of the burner module 21 in accordance with an exemplary embodiment of FIG. 10 of the present disclosure. In one embodiment, the gas header 46 includes a plurality of layers of wire mesh cassettes of 50-micron size, for example, to facilitate uniform diffusion of the incoming reactants along a longitudinal direction. The layers of wire mesh cassettes are supported by shelves provided inside the tubes 48. The layers of wire mesh cassettes facilitate to diffuse reactants along the length of the header 46 to ensure that each burner module 21 receives substantially equal amounts of the supplied reactants. The reactants enter the header 46 through fittings that connect the header 46 to the gas supply lines (typically flexible hoses). The reactants exit the header 46 through fittings and flexible hoses that connect the header 46 to the burner module(s) 21. In one embodiment, wire mesh cassettes/inserts are also provided inside the burner module(s) 21.

FIG. 12 illustrates a schematic bottom isometric view of the gas header 46 coupled to the base plate 40 of the burner module 21 in accordance with an exemplary embodiment of FIG. 10 of the present disclosure. In one embodiment, oxygen, hydrogen, and silicon tetrachloride are fed through the gas header 46 underneath the burner module(s) 21. Wire mesh cassettes/inserts inside the burner module 21 and/or pipe header 46 ensure that the reactants get distributed uniformly throughout the burner module(s) 21. The reactants eventually egress from the above-mentioned orifices and/or slits. Thereafter, these reactants react to form silica nano-particles that are deposited on the spindle.

FIG. 13 illustrates a schematic isometric view of the cooling fan 26 in accordance with an exemplary embodiment of the present disclosure. FIG. 14 illustrates a schematic side view of the cooling fan 26 in accordance with an exemplary embodiment of the present disclosure. In one embodiment, the cooling fan 26 may have one continuous slit 27 that is directed towards a central axis of the spindle. The cooling fan 26 may also have another continuous slit 27, if required, to direct air towards an adjacently placed workpiece/preform. In other words, the cooling fan 26 may be capable of cooling two workpieces/preforms simultaneously. The cooling fan 26 may include a plurality of wire mesh cassettes placed one above the other and restrained in place by shelves and the inclined lateral walls. Both ends of the cooling fan 26 are sealed by blind flanges. The cooling fan 26 is configured to supply compressed air to the workpiece/preform through an inlet 29. The wire mesh cassettes ensure that volume egress of air egress is uniform along a longitudinal direction of the slit length so that convective cooling effect on the workpiece is longitudinally uniform.

FIG. 15 illustrates a flow chart of a method 150 for outside vapor deposition of silica soot, in accordance with an embodiment of the present disclosure. At a step 152, reactant gas is supplied to a base plate 40 through a plurality of gas headers 46 and a plurality of tubes 48. At a step 154, the plurality of burner modules 21 is ignited using an automatic spark ignition unit to flame the reactant gas. At a step 156, ceramic rod is provided to a central axis of a spindle. At s step 158, focus of flames of the plurality of burner modules 21 is concentrated to the central axis of the spindle. At a step 160, coolant using a fan is provided to perform deposition of silica soot.

In accordance with the embodiments discussed herein, the exemplary burner system facilitates a higher percentage of the silica soot deposition because the orifices and/or slits of the burner module(s) are focused to the central axis of the spindle. In some embodiment, the actuation of the spindle is not required due to the uniformity of the distribution of the orifices and/or slits of the burner system along the length of the spindle. As a result, formation of conical ends of the silica ingot is prevented. Also, the unique cooling method of the workpiece, if required, ensures that a good thermal gradient exists between the workpiece and the silica soot particles, thereby enhancing silica soot deposition by thermophoresis.

While specific language has been used to describe the present disclosure, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The drawings and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.

,CLAIMS:We Claim:
1. A fuel-efficient burner system (20) for outside vapor deposition of silica soot, the system (20) comprising:
a plurality of burner modules (21) having a plurality of slits (28) to outflow reactant gas, wherein the plurality of burner modules (21) includes a recessed portion (32) and supported by a pair of inclined walls at extreme ends;
a spindle (22) aligned along a longitudinal direction parallel and placed over the plurality of burner modules (21), wherein the spindle (22) is supported by rods at extreme ends;
a hood (24) surrounding the plurality of burner modules (21) to enable a focus of the plurality of slits (28) to a central axis of the spindle (22), wherein the hood is a dome shaped structure having covered from sides, open at a narrow top at a distal end; and
a base plate (40) coupled to a bottom of the plurality of burner modules (21) and the hood (24).

2. The system as claimed in claim 1, wherein the plurality of burner modules (21) includes a top portion (34) having a plurality of channels (36) fluidically coupled to the plurality of slits (28).

3. The system as claimed in claim 2, wherein the plurality of channels (36) is formed between a pair of plates 38 of the top portion (34).

4. The system as claimed in claim 1, wherein the base plate (40) includes a plurality of projections coupled to a plurality of grooves at a base of the plurality of burner modules (21).

5. The system as claimed in claim 1, wherein the base plate (40) includes a plurality of bolt holes 44 to securely couple the top portion (34) and base plate (40).

6. The system as claimed in claim 1, wherein the base plate (40) includes a plurality of inlet holes (41) for enabling gas supply to the plurality of burner modules (21).

7. The system as claimed in claim 1, wherein the base plate (40) includes a plurality of gas headers (46) and a plurality of tubes (48) corresponding to each of the plurality of burner modules (21).

8. The system as claimed in claim 1, further comprising a fan (26) including a continuous slit (27) and an inlet (29).

9. The system as claimed in claim 1, further comprising an automatic spark ignition unit to ignite the plurality of burner modules (21).

10. A method (150) for outside vapor deposition of silica soot, the method comprising:
supplying reactant gas to a base plate (40) through a plurality of gas headers (46) and a plurality of tubes (48), wherein the plurality of gas headers (46) and a plurality of tubes (48) is fluidically coupled to the plurality of burner modules (21);
igniting the plurality of burner modules (21) using an automatic spark ignition unit to flame the reactant gas;
providing ceramic rod to a centre axis of a spindle;
concentrating focus of flames of the plurality of burner modules (21) to the centre axis of the spindle; and
providing coolant using a fan to perform deposition of silica soot.