CN201132815Y - Furnace equipment for the manufacture of optical fiber preforms - Google Patents

Abstract

The utility model relates to a shrinkage furnace device for manufacturing optical fiber preform rods, which includes a graphite heating furnace, and an air curtain sealing device and an air flow flushing device are arranged on one side of the graphite heating furnace corresponding to the end of the graphite bushing, and is characterized in that The air curtain sealing device and the air flow flushing device are composed of front and rear bushings arranged on the outer casing, wherein annular slits are formed at the connecting ends of the front and rear bushings, and annular air slits are arranged in the inner hole of the outer casing corresponding to the annular slits. The air guide and damping ring is arranged in the annular air chamber to form an air curtain sealing device; a radial through hole is opened on the rear bush along the circumferential direction, and an axial guide is set on the rear bush corresponding to the air outlet of the radial through hole. The air port corresponds to the radial through hole, and a rear annular air chamber is arranged in the inner hole of the jacket, and an air guide damping ring is arranged in the rear annular air chamber to form an airflow flushing device. The utility model has the advantages of simple structure, reasonable setting and convenient processing, and the setting of the gas guide and damping ring makes the sealing air flow evenly distributed and improves the airtight performance of the melting and shrinking furnace.

Description

Furnace equipment for the manufacture of optical fiber preforms

technical field

The utility model relates to a shrinkage furnace device for manufacturing optical fiber preform rods, which is a further improvement on the existing shrinkage furnace device and belongs to the technical field of optical fiber preform rod processing equipment.

Background technique

The optical fiber preform is usually made of a core rod and a glass sleeve, wherein the production of the core rod includes firstly using plasma chemical vapor deposition or other chemical vapor deposition to process pure silica or doped silica glass on the inner wall of the quartz tube. Deposition, after the deposition is completed, it is melted and shrunk into a rod, which is the optical fiber prefabricated core rod. The shrinking furnace device is the processing equipment that melts the deposited quartz tube into a mandrel. The shrinking furnace device for optical fiber preform mandrel is mainly composed of a graphite heating furnace and a graphite bushing installed in the middle of the graphite heating furnace. An air curtain sealing device and an airflow flushing device are installed at one end of the graphite bushing. The air curtain sealing device and the air flow flushing device of the existing shrinkage furnace device are formed by opening small circumferential holes and/or annular slits in the metal bushing. Due to the small aperture and thin annular slit, the structure of the parts is complicated, and the processing and The assembly is difficult and the process requirements are high, otherwise the uniformity of airflow distribution and airtightness will be affected; and the interface connection between the components is difficult to ensure the isolation between different gas paths. In addition, the metal bushing of this structure works at high temperature, is easy to be deformed and damaged, and has a short service life.

Contents of the invention

The technical problem to be solved by the utility model is to provide a melting and shrinking furnace device for optical fiber preform manufacturing with simple and reasonable structure, good manufacturability, easy manufacture and good airtight performance in view of the shortcomings of the above-mentioned prior art.

The technical scheme adopted by the utility model to solve the above-mentioned problems is as follows: it includes a graphite heating furnace and a graphite bushing 4 arranged in the middle of the graphite heating furnace, and a gas bushing is arranged at one end of the graphite heating furnace corresponding to the graphite bushing. The curtain sealing device and the airflow flushing device are different in that the air curtain sealing device and the airflow flushing device are composed of front and rear bushings 6, 8 arranged on the outer casing 7, wherein the connecting ends of the front and rear bushings are formed There is an annular slit 19, and an annular air chamber 16 is arranged in the inner hole of the outer jacket corresponding to the annular slit, and the annular air chamber is connected to the air inlet 18, and an air guide damping is arranged between the annular slit and the air inlet in the annular air chamber The ring 17 constitutes the air curtain sealing device; the rear bush 8 is provided with a radial through hole 15 along the circumference, corresponding to the radial through hole air outlet, and an axial air guide port 11 is set on the rear bush, corresponding to the radial The hole is provided with a rear annular air chamber 12 in the inner hole of the jacket, and the rear annular air chamber is connected to the air inlet 14. An air guide damping ring 13 is arranged between the radial through hole in the rear annular air chamber and the air inlet to form an air flow scouring device.

According to the above scheme, the annular slit 19 is conical and inclined to the outside to form an air curtain sealing device for blowing air outward.

According to the above scheme, the axial air guide port 11 provided on the rear bushing 8 is an annular axial air guide port, and the inner hole of the rear bush is provided with a guide cone surface 20 corresponding to the axial air guide port.

According to the above scheme, the rear end of the outer jacket 7 is a connecting disc, and a cooling water tank 9 is arranged in the connecting disc, and the two ends of the cooling water tank are respectively communicated with the water inlet 21 and the water outlet 22 to form a water cooling structure of the outer jacket, so that the outer jacket The operating temperature is reduced.

When the utility model is used, the deposited quartz tube is passed through the middle through hole of the graphite melting and shrinking furnace, and the working temperature of the graphite melting and shrinking furnace reaches about 2000° C. The quartz tube 10 is condensed into a solid rod. At this time, the inert gas is blown out through the air curtain sealing device at the entry end of the quartz tube on one side of the graphite melting furnace to form a sealed air curtain, which prevents the outside air from entering the high temperature area of the graphite furnace from the left end and prevents the quartz A new oxide layer is formed on the surface of the tube. At the same time, a certain flow rate of inert gas is blown out through the airflow flushing device, and the silicon carbide particles produced between the graphite liner and the quartz tube due to high temperature and the silicon dioxide volatilized on the surface of the quartz tube are quickly blown away. Go, and prevent the outside air from entering the high temperature zone of the graphite furnace from the right end, so as to realize the melting and shrinking of the quartz tube in the anaerobic state and ensure the processing quality of the optical fiber preform core rod.

The beneficial effects of the utility model are as follows: 1. Adopting the front and rear bushing structures to form the air curtain sealing device and the air flow scouring device, not only can form effective sealing, but also the structure is simple, the setting is reasonable, and it is easy to process; especially by setting the air guide damping ring To adjust the flow rate and flow rate of the gas, the gap of the annular slit and the diameter of the radial through hole can be relatively enlarged, so that the manufacturability of the workpiece processing is greatly improved, and the distribution of the sealing air flow is uniform, and the airtight performance is further improved; 2 . Corresponding to the axial air guide port, there is a diversion cone surface, which can further accelerate the scouring air flow and achieve a better surface scouring effect; 3. A cooling water tank is set on the connecting plate connecting the jacket and the graphite furnace, which can effectively reduce the sealing component. Working temperature, preventing deformation and oxidation of components, effectively prolonging the service life of components.

Description of drawings

Fig. 1 is a front sectional structure diagram of an embodiment of the present invention.

Fig. 2 is a frontal cross-sectional structural diagram of an air curtain sealing device and an airflow flushing device according to an embodiment of the present invention.

Fig. 3 is a right side view of Fig. 2 .

Detailed ways

Further illustrate the embodiment of the present utility model below in conjunction with accompanying drawing, comprise graphite heating furnace, described graphite heating furnace comprises graphite heating element 2 and copper conductive electrode 1, is surrounded with graphite heat insulation layer at the periphery of graphite heating element 3. Outside the graphite heat insulation layer is the shell 5 of the shrinking furnace. A tubular graphite bushing 4 is installed in the graphite heating body in the middle of the graphite heating furnace. The graphite bushing runs through the entire heating zone of the graphite heating furnace. The left end of the corresponding graphite bushing is equipped with a jacket 7 and front and rear bushings 6 and 8 that are configured with the inner hole of the jacket to form an air curtain sealing device and an air flow flushing device, wherein the connecting ends of the front and rear bushings are By controlling the axial spacing, an annular slit 19 is formed, the gap between the slits is 0.5±0.1mm, the annular slit is conical, inclined to the outside, and constitutes an air curtain sealing device for blowing outward, corresponding to the annular slit in An annular air chamber 16 is arranged in the inner hole of the outer jacket 7, and the annular air chamber is connected to the air inlet 18, and an air guide damping ring 17 is arranged between the inner annular slit in the annular air chamber and the air inlet, thereby forming an air curtain seal. Device; radial through-holes 15 are evenly distributed along the circumference on the rear bushing 8, and the diameter of the radial through-holes is 0.8±0.2mm, corresponding to the air outlet of the radial through-holes, an annular axial air guide port 11 is set on the rear bushing , the air outlet of the axial air guide port is equipped with a diversion cone 20, corresponding to the radial through hole inlet end, the rear annular air chamber 12 is arranged in the inner hole of the jacket, and the rear annular air chamber is connected with the air inlet 14. An air-guiding damping ring 13 is arranged between the radial through hole in the annular air chamber and the air inlet to form an airflow scouring device. The rear end of the outer jacket 7 is a connecting disc with a larger diameter, and a cooling water tank 9 is arranged in the connecting disc. The cooling water tank is in the shape of a large semicircle, and the two ends of the arc are respectively connected with the water inlet 21 and the water outlet 22 to form a jacket. The unique water-cooling structure can greatly reduce the working temperature of the coat.

Claims (7)

1. A shrinking furnace device for the manufacture of optical fiber preforms, comprising a graphite heating furnace and a graphite bushing (4) arranged in the middle of the graphite heating furnace, and one end of the graphite heating furnace corresponding to the graphite bushing is arranged There is an air curtain sealing device and an airflow scouring device, and it is characterized in that the air curtain sealing device and the airflow scouring device are composed of front and rear bushings (6, 8) equipped with an outer jacket (7), wherein the front and rear bushings The connecting end is formed with an annular slit (19), corresponding to the annular slit, an annular air chamber (16) is arranged in the inner hole of the overcoat, and the annular air chamber is connected with the air inlet (18). An air guide damping ring (17) is arranged between the air inlets to form an air curtain sealing device; a radial through hole (15) is opened on the rear bush (8) along the circumference, corresponding to the radial through hole air outlet An axial air guide port (11) is set on the rear bush, and a rear annular air chamber (12) is arranged in the inner hole of the jacket corresponding to the radial through hole. The rear annular air chamber is connected with the air inlet (14). An air-guiding damping ring (13) is arranged between the indoor radial through hole and the air inlet to form an airflow scouring device. 2. The melting and shrinking furnace device for manufacturing optical fiber preform according to claim 1, characterized in that the said annular slit (19) is conical and inclined to the outside, forming an air curtain seal for blowing air outwards device. 3. The shrinking furnace device for manufacturing optical fiber preforms according to claim 1 or 2, characterized in that the axial gas inlet (11) opened on the rear bushing is an annular axial gas inlet, and the rear bushing Corresponding to the axial air inlet, the sleeve inner hole is provided with a diversion cone surface (20). 4. The shrinking furnace device for manufacturing optical fiber preform according to claim 1 or 2, characterized in that the rear end of the jacket (7) is a connecting disc, and a cooling water tank (9) is arranged in the connecting disc ), the two ends of the cooling tank are communicated with the water inlet (21) and the water outlet (22) respectively, forming the water cooling structure of the overcoat. 5. The shrinking furnace device for manufacturing optical fiber preform according to claim 1 or 2, characterized in that the graphite heating furnace includes a graphite heating element (2) and a copper conductive electrode (1). The outer circumference of the heating element is surrounded by a graphite heat-insulating layer (3), and the outside of the graphite heat-insulating layer is a shrink furnace shell (5), and a tubular graphite bushing (4) is installed in the graphite heating body in the middle of the graphite heating furnace. The graphite bushing runs through the entire heating zone of the graphite furnace. On the left side of the graphite heating furnace corresponding to the end of the graphite bushing, a jacket (7) and front and rear bushings (6, 8) arranged with the inner hole of the jacket are installed to form a Air curtain sealing device and air scour device. 6. The shrinking furnace device for manufacturing optical fiber preform according to claim 1 or 2, characterized in that the gap between said annular slits is 0.5±0.1mm. 7. The shrink furnace device for manufacturing optical fiber preform according to claim 1 or 2, characterized in that the diameter of said radial through hole is 0.8±0.2 mm.

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