Patent Application
20060177788
This application claims priority to an application entitled “Burner For Fabricating Optical Fiber Preform,” filed with the Korean Intellectual Property Office on Feb. 4, 2005 and assigned Serial No. 2005-10564, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an optical fiber. More particularly, the present invention relates to an apparatus for fabricating silica glass such as an optical fiber preform.
2. Description of the Related Art
In general, an optical fiber preform is fabricated using a vapor-phase deposition method or a sol-gel method. According to the sol-gel method, a liquid-phase raw material is input into a mold. The mold is heated so that the liquid-phase raw material is changed into a gel-phase material. The gel-phase material is then sintered forming fabricating silica glass. The sol-gel method is performed under a low temperature atmosphere, which reduces the manufacturing cost of the silica glass. In addition, this also enables the composition of the silica glass to be easily adjusted.
The vapor-phase deposition method includes a modified chemical vapor deposition (MCVD) method, a vapor-phase axial deposition (VAD) method and an outside vapor deposition (OVD) method. According to the vapor-phase deposition method, a solid optical fiber preform is fabricated through a vapor reaction under a high-temperature atmosphere of about 1800° C. The vapor-phase deposition method requires expensive manufacturing equipment in order to fabricate the optical fiber preform while causing low productivity. However, the vapor-phase deposition method can obtain a high-quality optical fiber preform. When performing the vapor-phase deposition method, a burner is used in order to promote deposition of an evaporated raw material.
As shown in
However, if the temperature of the mixture exceeds the combustion point or if ignition occurs by an ignition source the conventional burners 10 and 20 may cause explosion or combustion in the mixing regions before the mixture of the fuels and the oxidizing agents are fed into the combustion units. Such a phenomenon is called a “backfire.” In order to prevent the backfire, one proposed method is to suppress any temperature increase in the mixing regions and control a cut-off order of the fuels and the oxidizing agents when turning off the burners, but the backfire problem still remains.
Such a conventional burner is called a “dispersing burner.” According to the dispersing burner, the fuel and the oxidizing agent are separately exhausted from the combustion unit and mixed with each other at an end of the combustion, so explosions only rarely occur. However, since the fuel and the oxidizing agent may be burned even if the fuel is not sufficiently mixed with the oxidizing agent, density of a mixing gas is irregularly formed in flames exhausted from the conventional burner. This causes unstable flames and imperfect combustion.
One aspect of the present invention relates to a burner for fabricating an optical fiber preform, capable of preventing a backfire phenomenon.
Another aspect of the present invention relates to a burner for fabricating an optical fiber preform, capable of obtaining stable flames and a perfect combustion by allowing fuels to be sufficiently mixed with oxidizing agents.
One embodiment of the present invention is directed to a burner used for fabricating an optical fiber perform. The burner includes a burner housing; a first body formed with a plurality of spraying ports, at least a part of the first body being accommodated in the burner housing; and a second body aligned in a length direction of the first body, at least a part of the second body being accommodated in the burner housing, an oxidizing agent being fed into the second body along an outer peripheral surface of the second body and a fuel being fed into the second body along an inner peripheral surface of the first body. The oxidizing agent is uniformly mixed with the fuel in the first body and a mixture thereof is exhausted to an exterior through the spraying ports.
The above and other aspects, features and embodiments of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. For the purposes of clarity and simplicity, a detailed description of known functions and configurations incorporated herein will be omitted as it may obscure the subject matter of the present invention.
As shown in
The first and second bodies 102 and 103 include, at a sidewall, at least one pair of injection ports 113 and 115. Fuels and oxidizing agents are fed into the burner housing 101 through the injection ports 113 and 115.
The first body 102 is formed at one end with a plurality of spraying ports 121. The first body 102 is formed at an inner portion with a cavity having a predetermined size, which is coupled to the spraying ports 121.
The second body 103 is accommodated in the burner housing 101 while being aligned in a length direction of the first body 102. The first body 102 is spaced from the second body 103 by a predetermined distance in order to form an oxidizing agent port 123 therebetween. The oxidizing agent port 123 is formed along an outer circumferential portion of the second body 103. A passage is formed between an outer peripheral surface of the second body 103 and an inner peripheral surface of the burner housing 101 in order to connect one of the injection ports 113 and 115 with the oxidizing agent port 123. The oxidizing agent is fed into the burner 100 through one of the injection ports. The oxidizing agent then moves along the outer peripheral surface of the second body 103 and flows into the first body 102 through the oxidizing agent port 123. The injection port 113 connected to the oxidizing agent port 123 is called an “oxidizing agent injection port.” The oxidizing agent port 123 is inclined towards the first body 102.
The other injection port 115 extends into the second body 103 to allow the fuel to be injected into the second body 103. The other injection port 115 is called a “fuel injection port.” The fuel injected into the second body 103 through the fuel injection port 115 is fed into the first body 102 through the second body 103.
The center plug 104 is inserted into the second body 103 so that one end of the second body 103 is closed by the center plug 104. The center plug 104 is formed at an outer peripheral portion thereof with a slot having a predetermined size, so that a cavity 141 is formed between the center plug 141 and the second body 103 when the center plug 104 has been accommodated in the second body 103. The cavity 141 is connected to the fuel injection port 115 such that the fuel can be fed into the first body 102 through the cavity 141. A fuel exhaust port 143 is formed between the cavity 141 and an end of the second body 103. The exhaust port 143 is spaced from the end of the second body 103.
When the oxidizing agent is fed into the burner 100, the oxidizing agent is introduced into the first body 102 through the oxidizing agent port 123 while generating a high-speed fluid flux. Such a high-speed fluid flux caused by the oxidizing agent introduced into the first body 102 may form a low-pressure region 131 between the fuel exhaust port 143 and the end of the second body 103. Due to the low-pressure region, the fuel provided in the cavity 141 is fed into the first body 102 through the fuel exhaust port 143. The fuel is fed into the first body 102 through the fuel exhaust port 143 and the low-pressure region 131 due to differential pressure between the low-pressure region 131 and the cavity 141. The oxidizing agent is mixed with the fuel in a mixing region 129 formed in the first body 102. As the oxidizing agent and fuel are continuously fed into the burner 100, pressure of the mixing region 129 may rise, so that mixing gas is exhausted to an exterior due to differential pressure between the mixing region 129 and the exterior.
The burner 100 is formed at an inner portion thereof with the mixing region 129 in which the fuel is mixed with the oxidizing agent. The mixture of the fuel and the oxidizing agent is sprayed to the exterior through the spraying ports 121, so the backfire phenomenon may not occur. In addition, since the fuel is sufficiently mixed with the oxidizing agent in the burner 100 before they are exhausted out of the burner 100, it is possible to obtain stable flame and perfect combustion.
As shown in
The burner housing 201 receives the first and second bodies 102 and 103 therein and includes at least one pair of injection ports 113 and 115 at a sidewall. Oxidizing agents are introduced into the burner housing 201 through the injection port 213. The injection port 213 is called a “first oxidizing agent injection port.”
A plurality of spraying ports 221a and 221b are formed at one end of the first body 202, which are coupled with the burner housing 201. The first body 202 includes, at an inner portion thereof, a cavity having a predetermined size, in which the spraying ports 221a and 221b are communicated with the cavity. In contrast to the first embodiment, in which one end of the first body 102 is closed, In the second embodiment, one end of the first body 202 is closed by the center plug 204 extending lengthwise along the burner housing 201. The spraying ports 221a and 221b are formed at an end of the center plug 204. In addition, the cavity formed in the first body 202 is positioned between an inner peripheral surface of the first body 202 and an outer peripheral surface of the center plug 204.
The second body 203 is inserted into the burner housing 201 while being aligned in a length direction of the first body 202. The first body 202 is spaced from the second body 203 by a predetermined distance in order to form an oxidizing agent port 223 therebetween. The oxidizing agent port 223 is formed along an outer circumferential portion of the second body 203. A passage is formed between an outer peripheral surface of the second body 203 and an inner peripheral surface of the burner housing 201 in order to connect the first oxidizing agent injection port 213 with the oxidizing agent port 223. The oxidizing agent is fed into the burner 200 through the first oxidizing agent injection port 213, moves along the outer peripheral surface of the second body 203 and flows into the first body 202 through the oxidizing agent port 223. The oxidizing agent port 223 is inclined towards the first body 202.
A first fuel injection port 215 is formed at an outer peripheral surface of the second body 203 and is connected to an inner portion of the second body 203. The fuel introduced into the second body 203 through the first fuel injection port 215 is fed into the first body 202 through the second body 203.
The center plug 204 is inserted into the second body 203 in order to close one end of the second body 203. The center plug 204 is provided at an outer peripheral surface thereof with a rib extending in a circumferential direction of the center plug 204. A cavity 241 is formed between the center plug 204 and the second body 203 when the center plug 204 has been inserted into the second body 203. The cavity 241 is coupled with the first fuel injection port 215 so that the fuel is fed into the first body 202 through the cavity 241. A fuel exhaust port 243 is formed between the cavity 241 and the end of the second body 203, in which the fuel exhaust port 243 is spaced from the end of the second body 203.
As described above, the center plug 204 extends lengthwise along the burner housing 201 and the end of the center plug 204 closes the end of the first body 202. In addition, plural spraying ports 221a and 221b are formed at the end of the center plug 204 to allow the cavity formed in the first body 202 to be coupled to the exterior.
In addition, one of the spraying ports 221a and 221b linearly extends along the center of the center plug 204 so that the spraying port (herein, the spraying port 221b) is aligned at the center of the plural spraying ports. The spraying port 221b formed at the center of the center plug 204 is coupled to a second fuel injection port 245 formed at the outer peripheral surface of the center plug 204.
In the meantime, the guide housing 205 receives the burner housing, the first body, the second body and the center plug therein. The guide housing 205 is formed with a perforation hole coupled to the first and second fuel injection ports 215 and 245 and the first oxidizing agent injection port 213. In addition, the guide housing 205 has a second oxidizing agent injection port 219. The oxidizing agent can be fed into the burner through the second oxidizing agent injection port 219 separately from the first oxidizing agent injection port 213. The oxidizing agent fed into the burner through the second oxidizing agent injection port 219 is introduced into the cavity formed between the inner peripheral surface of the burner housing 201 and the outer peripheral surface of the first body 202 while flowing along the outer peripheral surface of the burner housing 201. The first body 202 is formed with a plurality of guide holes 221c, which are coupled to the cavity formed between the burner housing 201 and the first body 202. Referring to
When the oxidizing agent is fed into the burner 200 through the first oxidizing agent injection port 213, the oxidizing agent is introduced into the first body 102 through the oxidizing agent port 223 while generating a high-speed fluid flux. Such a high-speed fluid flux caused by the oxidizing agent introduced into the first body 202 may form a low-pressure region 231 between the fuel exhaust port 243 and the end of the second body 203. Due to the low-pressure region 231, the fuel provided in the cavity 241 is fed into the first body 202 through the fuel exhaust port 243. The fuel is fed into the first body 202 through the fuel exhaust port 243 and the low-pressure region 231 due to differential pressure between the low-pressure region 231 and the cavity 241. The oxidizing agent is mixed with the fuel in a mixing region 229 formed in the first body 202. As the oxidizing agent and fuel are continuously fed into the burner 200, pressure of the mixing region 229 may rise, so that mixing gas is exhausted to the exterior due to differential pressure between the mixing region 229 and the exterior.
The burner 200 is formed at an inner portion thereof with the mixing region 229. The fuel is mixed with the oxidizing agent and the mixture of the fuel and the oxidizing agent is sprayed to the exterior through the spraying ports 221a and 221b, so the backfire phenomenon may not occur. In addition, since the fuel is sufficiently mixed with the oxidizing agent in the burner 200 before they are exhausted out of the burner 100, it is possible to obtain stable flame and perfect combustion.
In addition, the fuel and the oxidizing agent fed into the burner 200 through the second fuel injection port 245 and the second oxidizing agent injection port 219 are exhausted to the exterior through the spraying port 221b formed at the center of the first body 202 and the guide holes 221c. The fuel fed into the burner 200 through the second fuel injection port 245 is exhausted out of the first body 202 while being burned together with mixing gas formed in the first body 202. In addition, the oxidizing agent exhausted to the exterior through the guide hole 221c may flow along a peripheral area of the mixing gas to allow the mixing gas to be stably burned. A part of the oxidizing agent can be mixed with the mixing gas in order to adjust a mixing ratio of the mixing gas.
As described above, the fuel and the oxidizing agent are separately fed into the burner and mixed with each other in the burner, thereby preventing the backfire phenomenon. In addition, since the fuel is mixed with the oxidizing agent in the burner just before the mixing gas is sprayed to the exterior from the burner, the backfire phenomenon may not occur. Furthermore, since the mixture of the fuel and the oxidizing agent is sprayed to the exterior after the fuel has been sufficiently mixed with the oxidizing agent in the burner, it is possible to obtain the perfect combustion for the mixing gas.
While the invention has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-10564 | Feb 2005 | KR | national |
