Graphite component for heating optical fiber preform of optical fiber drawing furnace
Technical Field
The invention relates to a graphite component, in particular to a graphite component for heating an optical fiber preform of an optical fiber drawing furnace.
Background
The graphite component is an important component of the optical fiber drawing furnace, an induction coil is sleeved on the outer side of the graphite component, an optical fiber preform to be heated is inserted into an inner hole of the graphite component, an alternating magnetic field is generated after the induction coil is electrified, so that the graphite component generates eddy currents, the graphite component is heated by the thermal effect of the eddy currents, and the optical fiber preform is heated by the high-temperature graphite component. In the actual production process, the optical fiber drawing furnace is difficult to achieve complete sealing, so that with the increase of the service time, the graphite component contacted with oxygen is slowly oxidized and needs to be replaced frequently, and therefore, the graphite component is a consumable product in the optical fiber drawing furnace.
The traditional graphite component is formed by splicing four sub-components up and down, wherein the two sub-components at the top of the graphite component are closest to the furnace mouth of the optical fiber drawing furnace, are easier to contact with oxygen, and if not replaced in time, the oxidized graphite component is easy to fall off ash, so that the strength of an optical fiber preform product is reduced, and if serious, the optical fiber preform product is scrapped; in addition, because the oxidation resistance of two sub-components at the top of the graphite component is poor, the replacement frequency is high, and the graphite component is expensive, so that the replacement cost is high, but if the shape of the graphite component is changed at will to reduce the volume, the size of the graphite component is easy to change, and the graphite component cannot be smoothly assembled on the furnace mouth of the optical fiber drawing furnace, so that the graphite component for heating the optical fiber preform of the optical fiber drawing furnace needs to be improved.
Disclosure of Invention
The invention aims at: the surface area is smaller, the ash drop condition is reduced, the oxidation resistance is enhanced, the volume is smaller, and the use cost is saved; the graphite component for heating the optical fiber preform of the optical fiber drawing furnace solves the problems of large surface area, serious ash drop, poor oxidation resistance, large volume, increased use cost and the like existing in the existing graphite component.
The technical scheme of the invention is as follows:
A graphite subassembly that is used for optical fiber drawing furnace optical fiber perform to heat, it comprises sleeve, combination section of thick bamboo and muffle tube, its characterized in that: a combined cylinder is sleeved in the port at the top end of the sleeve, an inner hole of the combined cylinder is communicated with an inner hole of the sleeve, a muffle tube is fixedly arranged at the bottom of the sleeve, the inner hole of the muffle tube is communicated with the inner hole of the sleeve, and the muffle tube, the sleeve and the combined cylinder are clamped on a furnace mouth of an optical fiber drawing furnace; the combined cylinder is provided with a first flange, and the combined cylinder above the first flange is provided with a second flange.
Transverse air holes are uniformly distributed on the circumference of the second flange.
The bottom of the first flange is provided with a limit groove.
The limiting groove is an annular groove, and vertical air holes are uniformly distributed in the limiting groove.
The vertical air holes are communicated with the horizontal air holes.
The top of the sleeve is clamped in the limiting groove, the outer diameter of the sleeve is equal to that of the limiting groove, and the inner diameter of the sleeve is larger than that of the limiting groove.
The inner wall of the sleeve and the outer wall of the combined cylinder form an air inlet annular space.
The muffle tube is in a funnel shape.
The invention has the advantages that:
The graphite component for heating the optical fiber preform of the optical fiber drawing furnace has the characteristics of smaller surface area, reduced ash falling condition, enhanced oxidation resistance, smaller volume and use cost saving, optimizes two sub-components at the top of the traditional graphite component, adopts a combined cylinder as a substitute thereof, not only maintains the external dimension, but also reduces the surface area and the volume of the combined cylinder, solves the problems of larger surface area, serious ash falling, poor oxidation resistance and larger volume existing in the existing graphite component, and meets the production requirement of the optical fiber preform.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is an enlarged schematic view of a portion of FIG. 1 at A;
FIG. 3 is a schematic perspective view of a composite cylinder according to the present invention;
FIG. 4 is a schematic bottom view of the composite cartridge of the present invention;
fig. 5 is a schematic structural view of a conventional graphite assembly.
In the figure: 1. the annular air inlet device comprises a sleeve, 1-1 parts of an air inlet annulus, 2 parts of a combined cylinder, 2-1 parts of a first flange, 2-2 parts of a second flange, 2-3 parts of a limiting groove, 2-4 parts of a vertical air hole, 2-5 parts of a horizontal air hole, 3 parts of a muffle tube, 4 parts of a sub-part A,5 parts of a sub-part B.
Detailed Description
The graphite component for heating the optical fiber preform of the optical fiber drawing furnace consists of a sleeve 1, a combined cylinder 2 and a muffle tube 3, wherein the combined cylinder 2 is sleeved in the top end port of the sleeve 1, the inner hole of the combined cylinder 2 is communicated with the inner hole of the sleeve 1, the lower part of the combined cylinder 2 is sleeved in the sleeve 1, the upper part of the combined cylinder 2 extends to the outside of the sleeve 1, a first flange 2-1 is arranged on the combined cylinder 2 extending to the outside of the sleeve 1, and the outer diameter of the first flange 2-1 is equal to the outer diameter of a sub-component B5 of the existing graphite component, so that the graphite component can be smoothly assembled on a furnace mouth of the optical fiber drawing furnace; the first flange 2-1 has an axial limiting effect on the combined cylinder 2, so that the combined cylinder 2 cannot completely enter the sleeve 1.
The bottom of the first flange 2-1 is provided with a limit groove 2-3, the limit groove 2-3 is an annular groove, the top end of the sleeve 1 is clamped in the limit groove 2-3, and the outer diameter of the sleeve 1 is equal to the outer diameter of the limit groove 2-3, so that the limit groove 2-3 has a radial limit effect on the sleeve 1, and the sleeve 1 is prevented from moving radially relative to the combined cylinder 2; the inner diameter of the sleeve 1 is larger than that of the limit groove 2-3, namely the top end of the sleeve 1 is not completely filled with the limit groove 2-3, vertical air holes 2-4 are uniformly distributed in the limit groove 2-3 on the inner side of the sleeve 1, and the vertical air holes 2-4 are used for discharging protective gas.
Because the top end of the sleeve 1 is not completely filled with the limit groove 2-3, but a certain gap is reserved between the limit groove 2-3, the inner wall of the sleeve 1 is not contacted with the outer wall of the combined cylinder 2, the inner wall of the sleeve 1 and the outer wall of the combined cylinder 2 form an air inlet annulus 1-1, the air inlet annulus 1-1 is communicated with the vertical air holes 2-4, the protective air leaving the vertical air holes 2-4 enters the furnace body of the optical fiber drawing furnace through the air inlet annulus 1-1, the annular structure of the air inlet annulus 1-1 can uniformly spread the protective air in the furnace, so that the high temperature field in the furnace is more stable, the fluctuation of the wire diameter of an optical fiber preform is reduced, the oxidation speed of the optical fiber drawing furnace is reduced, and the aim of optimizing the drawing production index of the optical fiber preform is fulfilled.
The second flange 2-2 is arranged on the combined cylinder 2 above the first flange 2-1, the outer diameter of the second flange 2-2 is equal to the outer diameter of the sub-component A4 of the existing graphite component, so that the graphite component can be smoothly assembled on a furnace mouth of an optical fiber drawing furnace, the second flange 2-2 is utilized to replace the sub-component A4 of the existing graphite component, the self volume is greatly reduced, the manufacturing cost is lowered, and the using cost of the graphite component is further lowered, in addition, the area of the second flange 2-2, which is contacted with oxygen, is reduced correspondingly to the sub-component A4, so that the oxidation resistance is enhanced, the ash drop condition is reduced, and the quality of an optical fiber preform product is not affected.
The circumference of the second flange 2-2 is uniformly provided with transverse air holes 2-5, the transverse air holes 2-5 are used for injecting protective gas into the optical fiber drawing furnace, the protective gas is inert gas, and the protective gas is used for exhausting air in the optical fiber drawing furnace so as to reduce the oxidation speed of the graphite component; the transverse air holes 2-5 on the second flange 2-2 are communicated with the vertical air holes 2-4 on the first flange 2-1, and the protective air enters the air inlet annulus 1-1 through the transverse air holes 2-5 and the vertical air holes 2-4 and then downwards enters the optical fiber drawing furnace, so that the high temperature field in the optical fiber drawing furnace is more uniform.
The bottom of the sleeve 1 is fixedly provided with a muffle tube 3, the muffle tube 3 is in a funnel shape, an inner hole of the muffle tube 3 is communicated with an inner hole of the sleeve 1, the muffle tube 3 is used for converging the airflow of the protective gas, the air is prevented from entering the optical fiber drawing furnace, the muffle tube 3, the sleeve 1 and the combined cylinder 2 are clamped on the furnace mouth of the optical fiber drawing furnace, and the muffle tube 3, the sleeve 1 and the combined cylinder 2 are all made of graphite so as to be matched with an external induction coil to generate heat, and the high Wen Duiguang fiber preform is utilized for heating;
The working process of the graphite component is as follows: the combined cylinder 2 is inserted into the upper port of the sleeve 1, so that the sleeve 1 is clamped in the limiting groove 2-3, and then the muffle tube 3 is fixedly arranged at the bottom of the sleeve 1, thus completing the installation work of the graphite component. And assembling the graphite component which is completely installed on a furnace mouth of an optical fiber drawing furnace, and then injecting protective gas into the drawing furnace through the transverse air holes 2-5.
The protective gas enters the graphite component through the transverse air holes 2-5 on the second flange 2-2, then enters the air inlet annulus 1-1 downwards through the vertical air holes 2-4 in the first flange 2-1, the annular structure of the air inlet annulus 1-1 can enable the protective gas to be uniformly dispersed in the furnace, so that a high temperature field in the furnace is more stable, the fluctuation of the wire diameter of the optical fiber preform rod is reduced, and the oxidation speed of the optical fiber drawing furnace is reduced; and the air inlet annulus 1-1 is formed by matching the inner wall of the sleeve 1 with the outer wall of the combined cylinder 2, and the position of the shielding gas entering the furnace through the air inlet annulus 1-1 is lower than that of the traditional graphite component, so that the effect of uniformly distributing the shielding gas is optimized.
After the shielding gas leaves the air inlet annulus 1-1, the shielding gas downwards enters the optical fiber drawing furnace through the muffle tube 3 and extrudes air in the furnace, so that the oxidation speed of the graphite component is reduced, the service life of the graphite component is prolonged, when the air in the furnace is emptied, the induction coil sleeved outside the graphite component is electrified, an alternating magnetic field is generated after the induction coil is electrified, the graphite component generates vortex, the graphite component is heated by the thermal effect of the vortex, and the optical fiber preform is heated by the high-temperature graphite component, so that the production work of optical fiber preform drawing is performed.
Because the combined cylinder 2 is closest to the furnace mouth of the optical fiber drawing furnace and is easier to contact with the outside air, after long-term use, the oxidation speed of the combined cylinder 2 is faster than that of the sleeve 1 and the muffle tube 3, and the combined cylinder needs to be replaced regularly; since the combined cylinder 2 has a smaller surface area relative to the sub-parts A4 and B5 of the conventional graphite assembly and a smaller area for contacting air, the oxidation rate is slower relative to the conventional graphite assembly, reducing the replacement frequency; and the combined cylinder 2 is smaller in volume relative to the sub-parts A4 and B5 of the conventional graphite assembly, reducing the use cost, so that the graphite assembly significantly reduces the replacement and use costs by combining the two aspects.
The graphite component has the characteristics of smaller surface area, reduced ash falling, enhanced oxidation resistance, smaller volume and use cost saving, optimizes two sub-components at the top of the traditional graphite component, adopts the combined cylinder 2 as a substitute thereof, not only maintains the external dimension, but also reduces the surface area and volume of the graphite component, solves the problems of larger surface area, serious ash falling, poor oxidation resistance and larger volume existing in the traditional graphite component, and increases the use cost, and meets the production requirement of the optical fiber preform.