CN211999487U - Optical fiber perform vacuum sintering stove - Google Patents

Abstract

The utility model relates to an optical fiber perform vacuum sintering stove, including stove outer covering (1), heating tube (3) set up in stove outer covering (1), one end sets up evacuation takeover (15), the other end sets up admits air and takes over (6), and the loose body of optical wand hangs in heating tube (3), heating tube (3) outer wall sets gradually thermal-insulated covering (4) and heat-insulating tube (5), heat-insulating tube (5) outer wall sets up heating coil (2), and this heating coil (2) can be along heating tube (3) axial reciprocating motion in the annular gap between heat-insulating tube (5) and stove outer covering (1). In order to improve the axial even heating to the loose body of optical wand, this application designs induction coil for axial reciprocating motion formula, lets induction coil lead to long heating to the heating tube to improve the homogeneity of heating tube axial heating temperature.

Description

Optical fiber perform vacuum sintering stove

Technical Field

The utility model relates to a sintering furnace, concretely relates to with loose body sintering optical fiber perform of silica.

Background

The optical fiber preform is produced through the reaction of high purity metal halide vapor and oxygen in a torch of special structure to form silica particle, deposition on the core rod to obtain loose body, and sintering to obtain transparent quartz glass body as the optical fiber preform. The loose body sintering furnace of the optical fiber perform is one of key devices for manufacturing the optical fiber perform, and the performance of the sintering furnace determines key parameters of the optical fiber perform, such as refractive index distribution, water peak hydroxyl (OH) content and the like.

The existing optical fiber perform rod sintering process is that a sintering device is utilized to suspend the loose body of the optical fiber perform rod in a high temperature resistant quartz tube, and Cl is sequentially introduced into the tube₂The method is used for eliminating the problem of high OH content in the loose body, and the problem of more bubbles in the sintering process of the loose body can be solved by introducing He gas, so that the compact transparent sintered optical fiber preform with less bubbles and low OH content is obtained. The device comprises a sintering furnace, a quartz central tube, a silicon-molybdenum rod heating element, a graphite heat-insulating layer and a prefabricated rod loose body suspension mechanism which are arranged in a cavity of the sintering furnace, an up-and-down mechanism of the loose body, a rotating mechanism, a quartz central tube opening air draft device and the like.

The key properties of the optical fiber perform sintering furnace comprise temperature control precision, temperature field uniformity, furnace body sealing property and the like. Wherein, the insufficient or fluctuating temperature control precision of the sintering furnace can seriously affect the product quality, and the too low temperature can cause that the loose body of the optical fiber preform can not be completely dehydrated or sintered completelyObviously, if the temperature is too high, the optical fiber preform is easy to melt and is stretched and deformed under the action of self weight, if the temperature is too high, the deviation of the outer diameter uniformity of the rod body is large, wire drawing is not facilitated, if the temperature is too high, the rod body is melted and falls, and a sintering furnace is smashed; in addition, the uniformity of the temperature field of the high-temperature region of the sintering furnace must be stable, and the sintered optical fiber preform product can be transparent in the whole body, and the internal stress distribution meets the requirements and the like; finally, the sealing requirement of the central tube of the sintering furnace is higher, and firstly, the introduced dehydrating agent Cl₂The dehydrating agent is dangerous chemical and extremely toxic, if the leakage has serious potential safety hazard, the using amount of the dehydrating agent can be effectively controlled due to good sealing property, the cost is reduced, and the problem that the loose body can not be completely dehydrated due to the fact that external air permeates into a heating central area due to poor sealing property is solved.

However, the temperature accuracy and the temperature field homogeneity of present optical fiber perform fritting furnace are difficult to guarantee, for guaranteeing the good performance parameter of optical fiber perform, optical fiber perform need reciprocate when sintering in the fritting furnace to make optical fiber perform's surface sinter evenly, but optical fiber perform reciprocates on one side rotatoryly and has the risk of falling the stick, in case take place to fall the stick accident, then need readjust, change the key equipment part of fritting furnace, influenced the long-term stability of fritting furnace.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem who solves: the temperature accuracy and the temperature field homogeneity of current optical fiber perform fritting furnace are difficult to guarantee long-term stability, and optical fiber perform is rotatory simultaneously and reciprocates and has great stick risk that falls.

The utility model provides a technical scheme that above-mentioned technical problem adopted does, an optical fiber perform vacuum sintering stove, including stove outer covering, heating tube, the heating tube sets up in the stove outer covering, one end sets up evacuation takeover, the other end sets up admits air and takes over, and the loose body of optical wand hangs in the heating tube, the heating tube outer wall sets gradually thermal-insulated covering and thermal-insulated pipe, thermal-insulated outer wall of the pipe sets up heating coil, and this heating coil can be along heating tube axial reciprocating motion in the annular gap between thermal-insulated pipe and stove outer covering.

Preferably, the thermal insulation covering layer is hard felt thermal insulation cotton, plays a role in heat preservation of the heating tube and contributes to improving the axial heating temperature uniformity of the heating tube.

Preferably, the heat insulation pipe is a glass heat insulation pipe.

Preferably, the heating tube is a graphite heating tube and is heated by induction of an induction coil.

Preferably, the top of the heating tube is provided with a hanging sleeve, the loose body of the optical rod is hung at the lower end of the hanging sleeve, and the hanging sleeve is connected with a rotating motor to drive the loose body of the optical rod to rotate.

Preferably, the furnace shell is made of steel, and the inner wall of the furnace shell is hollow to form a water cooled wall. The steel furnace shell is high temperature resistant and not easy to deform.

Preferably, the heating coil is installed on the coil support, the lower end of the furnace shell is provided with an installation base, the installation base is provided with a motion lead screw, the motion lead screw and the installation base are in screw fit, the motion lead screw is connected with a rotating motor and can axially reciprocate relative to the installation base, and the motion lead screw is connected with the coil support to push the coil support to axially reciprocate in the annular gap.

In order to improve the running stability of the induction coil, the coil support is provided with a motion guide rod extending axially, the motion guide rod is parallel to the motion lead screw, and when the motion lead screw axially displaces relative to the mounting base, the motion guide rod is simultaneously in sliding fit with the mounting base.

Compared with the prior art, the utility model has the advantages of: the utility model discloses the loose body of optical wand only need make rotary motion in the heating tube, need not realize the thermally equivalent through upper and lower displacement. In order to improve the axial even heating to the loose body of optical wand, this application designs induction coil for axial reciprocating motion formula, lets induction coil lead to long heating to the heating tube to improve the homogeneity of heating tube axial heating temperature.

This application adopts the displacement of motion lead screw drive induction coil, more is favorable to the control to the induction coil displacement condition, and is simple effective. An air inlet connecting pipe is arranged at the bottom of the heating pipe, a vacuumizing connecting pipe is arranged at the top of the heating pipe, and Cl is sequentially introduced through the air inlet connecting pipe₂The method is used for solving the problem of high OH content in the loose body, and the problem of more bubbles in the sintering process of the loose body can be solved by introducing He gas, so that the compact transparent sintered optical fiber preform with low OH content and less bubbles can be obtained.

Drawings

FIG. 1 is a schematic structural diagram of a vacuum sintering furnace for an optical fiber preform according to an embodiment of the present invention;

fig. 2 shows a movement structure of a heating coil according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the embodiments of the drawing, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

The embodiment relates to an optical fiber perform vacuum sintering stove, including stove outer covering 1, graphite heating tube 3 sets up in stove outer covering 1 center, and the upper end sets up the end cover, sets up evacuation takeover 15 again on the end cover, the lower extreme sets up admits air and takes over 6, takes over 15 messenger heating tube inside negative pressure that forms through the evacuation. A hanging sleeve 14 is further arranged on the end cover, the light rod loose body is hung at the lower end of the hanging sleeve 14, and the hanging sleeve 14 is connected with a first rotating motor 16 and driven to rotate.

The outer wall of the graphite heating tube 3 is wrapped with hard felt heat insulation cotton to form a heat insulation covering layer 4, a glass heat insulation tube 5 is sleeved outside the heat insulation covering layer 4, a heating coil 2 is movably sleeved on the outer wall of the glass heat insulation tube 5, and the heating coil 2 can axially reciprocate along the heating tube 3 in a closed annular gap between the heat insulation tube 5 and the furnace shell 1, so that the graphite heating tube 3 is uniformly heated.

This application adopts the steel stove outer covering, and stove outer covering inner wall cavity forms the water-cooling wall, and the water-cooling wall cools off the stove outer covering through cooling water.

The heating coil moves along the graphite heating tube in the axial direction: the heating coil 2 is installed on the coil support 11, the bottom of the furnace shell 1 is provided with an installation base 7, the installation base 7 is provided with a motion lead screw 8, and the motion lead screw 8 is connected with a second rotating motor 9 and can axially reciprocate linearly relative to the installation base 7. The moving lead screw 8 is fixedly connected with the coil support 11, so that the coil support is indirectly pushed to axially reciprocate in the annular gap. A pair of axially extending motion guide rods 10 are fixedly connected to the coil support 11, the two motion guide rods 10 are respectively located on two sides of the motion screw 8 and are arranged in parallel, and the motion guide rods 10 are in sliding fit with the mounting base 7 to balance the displacement of the auxiliary motion screw 8.

Although the preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that modifications and variations of the present invention are possible to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. The utility model provides an optical fiber perform vacuum sintering stove which characterized in that: including stove outer covering (1), heating tube (3) set up in stove outer covering (1), one end sets up evacuation takeover (15), the other end sets up admits air and takes over (6), and the loose body of optical wand hangs in heating tube (3), heating tube (3) outer wall sets gradually thermal-insulated covering (4) and thermal-insulated pipe (5), thermal-insulated pipe (5) outer wall sets up heating coil (2), and this heating coil (2) can be along heating tube (3) axial reciprocating motion in the annular gap between thermal-insulated pipe (5) and stove outer covering (1).

2. The furnace of claim 1, wherein: the heat insulation covering layer is made of hard felt heat insulation cotton.

3. The furnace of claim 1, wherein: the heat insulation pipe is a glass heat insulation pipe.

4. The furnace of claim 1, wherein: the heating tube is a graphite heating tube.

5. The furnace of claim 1, wherein: the heating tube top is provided with hangs sleeve (14), and the loose body of smooth rod hangs hang sleeve (14) lower extreme, hang sleeve (14) and connect first rotating electrical machines (16) and drive the loose body of smooth rod rotatory.

6. The furnace of claim 1, wherein: the furnace shell (1) is made of steel, and the inner wall of the furnace shell is hollow to form a water-cooled wall.

7. The furnace of claim 1, wherein: the heating coil is installed on a coil support (11), the lower end of the furnace shell (1) is provided with a mounting base (7), the mounting base (7) is provided with a motion lead screw (8) and is in screw fit with the motion lead screw, the motion lead screw (8) is connected with a second rotating motor (9) and can move axially and reciprocally relative to the mounting base (7), the motion lead screw (8) is connected with the coil support (11), and the coil support is pushed to move axially and reciprocally in an annular gap.

8. The furnace of claim 7, wherein: the coil support (11) is provided with a motion guide rod (10) extending axially, the motion guide rod (10) is parallel to the motion lead screw (8), and when the motion lead screw (8) axially displaces relative to the mounting base (7), the motion guide rod (10) is simultaneously in sliding fit with the mounting base (7).

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