Patent Grant
10882777
The present disclosure generally relates to burners, and more particularly to adjustable fume tubes of silica particle burners.
Outside vapor deposition (OVD) processes are used for the production of optical fiber preforms. Certain burners may be able to make one preform blank in a single run. Both soot capture efficiency and laydown rate are important to the overall cost of fiber manufacturing. However, increased laydown rates often have a deleterious effect on the efficiency of the soot capture by the optical fiber preform. Accordingly, new methods and systems of increasing soot capture efficiency and laydown rate may be desirable.
According to at least one example of the present disclosure, a method of forming an optical fiber preform includes the steps: igniting a burner having a fume tube assembly to produce a first spray size of silicon dioxide particles; depositing the silicon dioxide particles on a core cane to produce a soot blank; and adjusting an effective diameter of an aperture of the fume tube assembly to produce a second spray size of the silicon dioxide particles. The second spray size is larger than the first spray size.
According to another example of the present disclosure, a burner includes a back block and a face block. The face block defines a plurality of gas emitting regions. A fume tube assembly extends through the face block and is surrounded by the gas emitting regions. The fume tube assembly includes a first fume tube coupled to the face block. A second fume tube is positioned within the first tube. An aperture is defined at an end of the fume tube assembly. An actuator is coupled with the second fume tube and configured to move the second fume tube within the first fume tube to adjust an effective diameter of the aperture.
According to another example of the present disclosure, a burner includes a face block defining a plurality of gas emitting regions. A fume tube assembly extends through the face block and is surrounded by the gas emitting regions. The fume tube assembly includes a first fume tube. A second fume tube is movably positioned within the first tube and defines an exterior surface. The exterior surface is tapered. An aperture is defined at an end of the fume tube assembly. An actuator is coupled with the second fume tube and configured to move the second fume tube within the first fume tube to variably adjust an effective diameter of the aperture.
These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.
The following is a description of the figures in the accompanying drawings. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.
Additional features and advantages of the invention will be set forth in the detailed description which follows and will be apparent to those skilled in the art from the description, or recognized by practicing the invention as described in the following description, together with the claims and appended drawings.
As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.
In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions.
Referring now to
Referring now to
The soot blank 58 of the optical fiber preform 50 grows (e.g., in thickness and diameter) with time as silica soot from the burner 10 is deposited thereon. In other words, the target (e.g., the soot blank 58) of the burner 10 grows in size with time. For example, the optical fiber preform 50 may grow from about 20 mm in diameter (e.g., essentially the diameter of the core cane 54) to about 300 mm in size (e.g., the diameter of the core cane 54 and soot blank 58) over the course of the deposition or laydown process. As such, deposition of the silica soot onto the optical fiber preform 50 may be broken into a plurality of stages. According to at least one example, the deposition of the silica soot from the burner 10 onto the optical fiber preform 50 may be broken into an early-stage, a transition stage, and a late stage.
In the early stage, the optical fiber preform 50 may provide a small target area (e.g., just the core cane 54) for the burner 10 and as such a first spray size of the silica soot particles from the burner 10 may be small. The first spray size may have a diameter of from about 0.5 cm to about 2.4 cm, or from about 0.8 cm to about 2.0 cm at from about 8 cm to about 10 cm from the aperture 38 of the fume tube assembly 26. In a specific example, the first spray size may have a diameter of about 1.2 cm at about 9 cm from the aperture. The spray size of the burner 10 may remain constant at the first spray size during the early stage. Keeping the first spray size of the burner 10 small while the optical fiber preform 50 is small in the early stage may be advantageous in increasing the soot capture, or efficiency, of the burner 10. For example, a smaller spray size may ensure that a greater quantity of the silica soot is captured by the preform 50 and does not merely pass by the preform 50. The early-stage of the laydown process may encompass the first 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes or 130 minutes of the deposition process. It will be understood that the size of the optical fiber preform 50 at the end of the early-stage may vary from process to process and may be dependent on factors such as size of the burner 10, desired size of the soot blank 58 and/or overall size of the optical preform 50.
As the optical fiber preform 50 grows in size, the laydown process may change to the transition state. In the transition state, the effective diameter of the aperture 38 of the fume tube assembly 26 may be adjusted and/or increased as explained in greater detail below. The increased effective diameter of the aperture 38 may provide a second spray size of the silica soot particles toward the optical fiber preform 50. According to various examples, the second spray size may be larger (e.g., wider, taller, and/or thicker) than the first spray size. For example, the second spray size may have a diameter of from about 1.0 cm to about 3.0 cm, or from about 1.2 cm to about 1.8 cm at from about 8 cm to about 10 cm from the aperture 38 of the fume tube assembly 26. In a specific example, the second spray size may have a diameter of about 1.5 cm at about 9 cm from the aperture. Although described as a stage, it will be understood that the transitional stage and the adjusting of the effective diameter of the aperture 38 may take place instantaneously or gradually over a period of time (e.g., greater than or equal to about one second, one minute, or greater than or equal to about 10 minutes).
The late stage state of the deposition process may take place once the optical fiber preform 50 reaches a predetermined thickness or deposition time. The late stage state of the deposition process may begin at about 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, 130 minutes into the laydown process and extend to the end of the process run. The spray size of the burner 10 may remain constant at the second spray size during the late stage. During the late stage state of the laydown process, the second spray size, which is larger than the first spray size, may facilitate a higher deposition rate of the silica soot onto the soot blank 58 while maintaining a desired level of silica soot capture (e.g., a desired level of efficiency). In other words, as the thickness of the soot blank 58 increases, it is able to accommodate the larger second spray size. As such, the silica soot from the burner 10 may be applied with a higher deposition rate. The amount of gas emitted from the gas emitting regions 22 of the burner 10, as well as the amount of silica soot produced by the fume tube assembly 26, may be increased in the late stage.
It will be understood that other examples of the laydown process may be implemented. For example, the laydown process may be divided into less than or greater than three stages. For example, when the fume tube assembly 26 includes greater than two fume tubes, the laydown process may include an additional transition stage and an intermediate stage between the transition stages. In examples of the burner 10 where the effective diameter of the aperture 38 may be smoothly transitioned over a majority or the entirety of the laydown process, the laydown process may effectively be a single transition stage, or the transition stage may extend over a large portion (e.g., greater than or equal to about 30 min) of the laydown process with an early stage and a late stage on either side of the transition stage.
Division of the deposition process into the early-stage, transition stage and late stage, and the adjusting of the effective diameter of the aperture 38 may not only be advantageous in increasing the capture efficiency of the silica soot by the optical fiber preform 50, but may also be advantageous in increasing the rate at which the silica soot particles are adhered to the optical fiber preform 50 (e.g., thereby shortening manufacturing time).
Still referring to
In use, the face block 18, manifold plate 70, back block 14 and fume tube assembly 26 are assembled as described below to form a subassembly which is mounted to the burner mounting block 74 through bolts 78. The actuator 42 is positioned rearward of the burner 10, and coupled to the second fume tube 34. It will be understood that the actuator 42 may be coupled to the burner mounting block 74 without departing from the disclosure provided herein. The actuator 42 is configured to move the second fume tube 34 coaxially within the first fume tube 30. Additionally or alternatively, the actuator 42 may be coupled with the first fume tube 30 such that the first fume tube 30 may move relative to the second fume tube 34. Further, the actuator 42 may be configured to function as a gas supply to the first and/or second fume tubes 30, 34 as explained in greater detail below. The fume tube assembly 26 may be press fit into back block 14. In this way, a precision alignment is achieved between the fume tube assembly 26 and the back block 14. The face block 18 of the burner 10 has a sliding fit over fume tube assembly 26 which provides alignment, as well as easy disassembly, of these components. In other words, the fume tube assembly 26 is extending through the face block 18.
During operation, the burner 10 is configured to emit a plurality of gasses. Some of the gasses may be shield gasses while other gasses are burned to aid in the production of the silica soot. The gas pumped through the first and/or second fume tubes 30, 34 of the fume tube assembly 26 is a fumed, or vaporized, silicon tetrachloride (Siltet) and/or octamethylcyclotetrasiloxane (OMCTS) and O2 mixture. Although disclosed in connection with Siltet and OMCTS, it will be understood that the any silica producing compound may be provided through the fume tube assembly 26. For example, tetraorthosilicate (TEOS) may also be provided through the fume tube assembly 26. As explained above, the actuator 42 may be the source of the Siltet and/or OMCTS and/or the O2. In the depicted example, the Siltet and/or OMCTS and O2 enter the burner 10 through the fume tube assembly 26, and ultimately exits the fume tube assembly 26 through the aperture 38. It will be understood that the fume tube assembly 26 may also include one or more inert gasses (e.g., N2) in addition to the Siltet and/or OMCTS and O2 without departing from the teachings provided herein. The burner 10 may have a flow rate of Siltet and/or OMCTS of from about 6 grams per minute to about 25 grams per minute, or from about 10 grams per minute to about 15 grams per minute. In a specific example, the flow rate of Siltet and/or OMCTS may be about 12.5 grams per minute. The flow rate of the O2 through the fume tube assembly 26 may be from about 1 slpm to about 10 slpm, or from about 2.5 slpm to about 8 slpm. In a specific example, the flow rate of O2 through the fume tube assembly 26 may be about 5.5 slpm.
Gas receiving apertures 90 of the back block 74 mate with gas supply lines and gas tight fittings to receive a CH4 and O2 premix. The CH4 and O2 premix enters the burner mounting block 74, proceeds through a gas passage 130 in the back block 14, passes through pressure equalizing orifices of manifold plate 70, and ultimately exits the burner's face through a gas burner region 134. The burner 10 may have a flow rate of CH4 of from about 1 slpm to about 7 slpm, or from about 2 slpm to about 5 slpm. In a specific example, the flow rate of CH4 may be about 3.5 slpm. The burner 10 may have a flow rate of premix O2 of from about 1 slpm to about 7 slpm, or from about 2 slpm to about 5 slpm. In a specific example, the flow rate of O2 may be about 2.8 slpm. The CH4 and O2 premix may be ignited and burned to provide heat which combusts the OMCTS and O2 mixture to produce the silica soot. The combustion of the OMCTS and O2, along with the shield gasses, propels the silica soot toward the optical fiber preform 50.
Inert gas receiving apertures receive an innershield N2. The innershield N2 enters burner mounting block 74 through a gas receiving aperture, proceeds through a gas passage in the back block 74, enters a central aperture 110, passes through an integral inner shield manifold of the manifold plate 70, and ultimately exits a face of the burner 10 through inner shield region 114. The burner 10 may have an innershield N2 flow rate of from about 1 slpm to about 7 slpm, or from about 2 slpm to about 5 slpm. In a specific example, the burner 10 may have an innershield N2 flow rate of about 3.2 slpm.
Outershield O2 enters the burner mounting block 74, proceeds through a gas passage and into an inner annulus 118, passes through a pressure equalizing orifice of the manifold plate 70, and ultimately exits a face of the burner 10 through outershield regions 122 and 126. The burner 10 may have an outer shield O2 flow rate of from about 4 slpm to about 20 slpm, or from about 6 slpm to about 13 slpm. In a specific example, the outer shield O2 flow rate may be about 9.9 slpm. As such, the outershield regions 122 and 126, inner shield region 114 and the gas burner region 134 may correspond to the gas emitting regions 22.
Referring now to the example depicted in
The first and second fume tubes 30, 34 may be made from a metal, a ceramic and/or combinations thereof. In metal examples, the metal may be a stainless steel (e.g., 303 stainless steel) and/or tungsten carbide (e.g., a composite material composed of tungsten carbide ceramics disposed within a cobalt matrix). Examples where the first and second fume tubes 30, 34 are composed of a hard metal and/or ceramic may be advantageous not only in providing scratch resistance, but also in allowing the precise formation of the first and second fume tubes 30, 34.
An inside diameter of the first fume tube 30 may be from about 1 mm (0.04 inches) to about 4 mm (0.16 inches), or from about 2 mm (0.08 inches) to about 3 mm (0.12 inches). An inside diameter of the second fume tube 34 may be from about 0.5 mm (0.02 inches) to about 5.5 mm (0.22 inches), or from about 2.0 mm (0.06 inches) to about 2.8 mm (0.11 inches). It will be understood that the inside diameter of the first and second fume tubes 30, 34 may take any of the values between the disclosed ranges. According to various examples, the outer diameter (e.g., the second exterior surface 34A) of the second fume tube 34 may be substantially, or approximately, equal to, that of the inside diameter (e.g., the first interior surface 30B) of the first fume tube 30 such that no gap exists between the first and second fume tubes 30, 34. It will be understood that a gap may be defined between the first and second fume tubes 30, 34 without departing from the teachings provided herein.
The aperture 38 is defined at an end of the fume tube assembly 26 and has an effective diameter. The effective diameter of the aperture 38 is the diameter of the fume tube assembly 26 through which the Siltet and/or OMCTS and O2 may exit. The effective diameter of the aperture 38 may correspond to an inner diameter of one of the fume tubes of the fume tube assembly 26 in some examples (e.g.,
Positioning of the first and second fume tubes 30, 34 to adjust the effective diameter of the aperture 38 may be advantageous in adjusting the spray size of the burner 10 based on the stage at which the silica soot laydown process is at. For example, during the early stage, when the relatively smaller first spray size is desirable, the ends of the first and second fume tubes 30, 34 may be substantially flush with one another such that the effective diameter of the aperture 38 is narrow (e.g., the diameter of the second fume tube 34). During the transitional stage, the actuator 42 may move the first and/or second fume tubes 30, 34 such that the effective diameter of the aperture 38 is substantially that of the inside diameter of the first tube 30. As such, the effective diameter of the aperture 38 is increased to produce the relatively larger second spray size which may be desirable for the late stage of the laydown process.
Referring now to
Similarly to the example depicted in
Use of the third fume tube 140 may be advantageous in increasing the efficiency of the silica set laydown process as compared to use of only the first and second fume tubes 30, 34. For example, use of the third fume tube 140 may allow the silica set laydown process to be broken into a greater number of stages (e.g., an additional laydown stage and an additional transitional stage) which may increase the capture efficiency of the silica set laydown process. For example, in the early stage the first, second and third fume tubes 30, 34, 140 may be substantially flush with one another such that the effective diameter the aperture 38 is that of the third fume tube 140 and thereby produces the relatively smaller first spray size. A transitional stage may exist where the third fume tube 140 is retracted into the fume tube assembly 26 to create a stepped region similar to that described above in connection with the first and second fume tubes 30, 34. This may allow an intermediate laydown stage where the effective diameter of the aperture 38 is substantially equal to that of the second fume tube 34 which may provide an intermediate spray size. Next, a second transition stage may occur where the second fume tube 34 is retracted into the first fume tube 30 such that the effective diameter of the aperture 38 is changed to that of the inside diameter of the first fume tube 30 thereby producing the relatively larger second spray size. With the increased number of spray sizes afforded by the third fume tube 140, the resulting spray size of the burner 10 may be more accurately tailored to the size of the optical fiber preform 50 which may increase the capture rate, or efficiency, of the burner 10.
Referring now to the depicted example of
In the depicted example, the first fume tube 30 defines a first tapered region 30C and the second fume tube 34 defines a second tapered region 34C. The first tapered region 30C may be tapered in a radially inward direction toward a center axis of the first fume tube 30 such that an inner diameter of the first tube 30 is smaller proximate the aperture 38 relative to an inner diameter over the rest of the first tube 30. The first tapered region 30C may be tapered at an angle β. The angle β may be less than or equal to about 10°, 9°, 8°, 7°, 6°, 5°, 4°, 3°, 2° or less than or equal to about 1°. The second tapered region 34C may be tapered in a radially inward direction, similar to that of the first tapered region 30C, such that an outer diameter of the second fume tube 34 is smaller proximate the aperture 38 than an outside diameter of the rest of the second fume tube 34. The second tapered region 34C may be tapered at an angle α. The angle α may be less than or equal to about 10°, 9°, 8°, 7°, 6°, 5°, 4°, 3°, 2°, or less than or equal to about 1°. According to various examples, the angles α and β may be complementary to one another such that the first tapered region 30C flushly engages, or couples, the second tapered region 34C of the second fume tube 34.
Similarly to the depicted examples of
In an exemplary operation (e.g., soot laydown process) of the presently depicted fume tube assembly 26, the fume tube assembly 26 may begin (e.g., an early stage of the laydown process) in the configuration depicted in
Use of the example of the fume tube assembly 26 depicted in
Referring now to
The method 150 may further include a step of emitting gas proximate the fume tube assembly 26. As explained above, the gas may be emitted proximate the fume tube assembly 26 through any one of the gas emitting regions 22 (e.g., inner shield N2, outershield O2 and/or the CH4 and O2 premix). The method 150 may further include a step of increasing a flow rate of the emitted gas after adjusting the effective diameter of the aperture 38. As the adjustment of the effective diameter of the aperture 38 allows a greater amount of Siltet and/or OMCTS and O2 to be emitted from the fume tube assembly 26, a corresponding increase in the amount of gas emitted from the emitting regions 22 may be increased to decrease turbulence and homogenize the spray of silica particles. The method 150 may further include a step of decoupling a tapered region (e.g., the second tapered region 34C) of the second fume tube 34 with a tapered region (e.g., the first tapered region 30C) of the first fume tube 30. As explained above, decoupling of the first and second tapered regions 30C, 34C increases the effective diameter of the aperture 38 and allows a greater OMCTS and O2 flow through the fume tube assembly 26. The method 150 may also include a step of moving the second fume tube 34 and the third fume tube 140 within the first fume tube 30. As explained above, moving of the second and third fume tubes 34, 140 within the first fume tube 30 alters the effective diameter of the aperture 38 such that an increased OMCTS and O2 flow may pass through the fume tube assembly 26 without added turbulence.
Use of the present disclosure may offer a variety of advantages. First, altering of the effective diameter of the aperture 38 allow for the burner 10 to provide a variable spray size of silica particles. The variable nature of the spray size allows the burner 10 to provide increased capture efficiency by producing a spray size that is based on the current size and/or diameter of the soot blank 58 of the optical fiber preform 50. Increase of the capture efficiency of the burner 10 may aid in cost savings for the production of silica soot. Second, as the effective diameter of the aperture 38 may be variably adjusted, a laydown rate, or rate of deposition of the silica soot on the optical fiber preform 50 may be increased. Third, as the disclosed fume tube assembly 26 is capable of adjusting the effective diameter of the aperture 38 dynamically while in operation, the burner 10 may not need to be shut down in order to increase laydown rate or change the spray size of the silica soot particles.
Modifications of the disclosure will occur to those skilled in the art and to those who make or use the disclosure. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the disclosure, which is defined by the following claims, as interpreted according to the principles of patent law, including the doctrine of equivalents.
It will be understood by one having ordinary skill in the art that construction of the described disclosure, and other components, is not limited to any specific material. Other exemplary embodiments of the disclosure disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.
For purposes of this disclosure, the term “coupled” (in all of its forms: couple, coupling, coupled, etc.) generally means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components. Such joining may be permanent in nature, or may be removable or releasable in nature, unless otherwise stated.
As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not a numerical value or end-point of a range in the specification recites “about,” the numerical value or end-point of a range is intended to include two embodiments: one modified by “about,” and one not modified by “about.” It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially” may denote values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.
It is also important to note that the construction and arrangement of the elements of the disclosure, as shown in the exemplary embodiments, is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts, or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures, and/or members, or connectors, or other elements of the system, may be varied, and the nature or numeral of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.
It will be understood that any described processes, or steps within described processes, may be combined with other disclosed processes or steps to form structures within the scope of the present disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.
It is also to be understood that variations and modifications can be made on the aforementioned structures and methods without departing from the concepts of the present disclosure, and, further, it is to be understood that such concepts are intended to be covered by the following claims, unless these claims, by their language, expressly state otherwise. Further, the claims, as set forth below, are incorporated into and constitute part of this Detailed Description.
This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/472,164 filed on Mar. 16, 2017 the content of which is relied upon and incorporated herein by reference in its entirety.
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