CN218321154U - Automatic sealing device for optical fiber perform extending furnace mouth - Google Patents

Abstract

The utility model discloses an optical fiber perform extends automatic sealing device of fire door, the device including locate the last fire door telescope tube sealing device who extends the stove top with locate the lower fire door hole shrink expansion sealing device who extends the stove below, go up fire door telescope tube sealing device and include two at least coaxial telescope tubes, lie in that the telescope tube of the most inside runs through and extends the stove inside and the two vertical reciprocating motion in step, have relative motion between two adjacent telescope tubes. The utility model provides an optical fiber perform extends automatic sealing device of fire door, go up fire door telescope tube sealing device and can extend and shorten automatically, hole shrink expansion sealing device can open automatically and contract under the lower fire door, and is sealed respond well, has reduced oxygen and has got into, has prolonged graphite spare life, has reduced product surface oxidation risk, and no impurity produces, is favorable to product quality's assurance, and the operation is simple, need not carry out other extra operations to the plug, has improved work efficiency.

Description

Automatic sealing device for optical fiber perform extending furnace mouth

Technical Field

The utility model belongs to the technical field of the optical fiber preparation, concretely relates to optical fiber perform extends automatic sealing device of fire door.

Background

An optical fiber preform (preform for optical fiber) is a core material for manufacturing a silica-based optical fiber, and is composed of a core layer and a clad layer. The mainstream production process of the existing optical fiber preform is a two-step method, wherein in the first step, a core layer is produced by adopting methods such as VAD, MCVD, OVD and the like; and secondly, adding a cladding on the core rod by RIC/RIT and OVD processes. No matter which process is adopted to add the cladding, a core layer product with large diameter fluctuation needs to be extended into a core rod with proper length, uniform diameter and no foreign matter on the surface, extension furnace equipment needs to be used in the process, the sealing performance of the extension furnace equipment is a key factor for stabilizing a temperature field in the furnace, whether the temperature field in the furnace is stable or not determines the uniformity of the diameter of the core layer, and on the other hand, the sealing in the furnace can reduce the risk of air entering the furnace and reduce the surface oxidation of the core rod.

The core rod extends equipment at present and adopts graphite induction furnace to heat the sandwich layer, and when the leakproofness was relatively poor, the inside graphite layer heating work of extension stove received oxygen oxidation easily, reduces its thermal insulation performance and reduces its life.

Chinese patent publication nos. CN207276494U, CN107555780A, CN201320691614X, CN207862191U, CN203728719U, etc. disclose a sealing device and method in an optical fiber drawing furnace, but the target object is an optical fiber preform, the scene is a state in which an upper clamp is fixed, and the diameter of a lower furnace mouth product is kept fixed, and the operation is different from the target object and the scene of the present application and is complicated, and manual confirmation or adjustment is required.

Chinese patent, publication number CN207276494U, CN107555780A discloses a sealing device under extension stove, set up many pairs of ring structure, the diameter size of passing through cylinder intelligent control according to extending stove lower extreme exit fiber optic fibre adjusts upper and lower graphite baffle circular pass passageway's size, the fiber perform of the different diameters of being convenient for extends smoothly, avoid simultaneously leading to the air to get into the problem that causes the furnace body oxidation because of the aperture is too big, it is fiber perform to the object, the operation is comparatively loaded down with trivial details, it is great to the hole clearance that the semi-ring shaped graphite plate closed the back and formed, be not suitable for the mandrel product that the diameter continuously changes, and need the different fiber diameter of artifical affirmation.

Chinese patent, publication No. CN201320691614.X, discloses that a disc-shaped base is arranged at a furnace mouth at the upper end of a heating cavity of a wire drawing furnace body, a temperature-resistant flexible sealing gasket is arranged in the disc-shaped base, and a radial elastic expansion device is arranged at the periphery of the temperature-resistant flexible sealing gasket. This patent can make the automatic flexible of sealed bore for keep less radial gap or zero clearance throughout when the wire drawing is fed between the undulant optical fiber perform of external diameter and the sealing device, set up inert gas blowing channel on the chamber that generates heat simultaneously, form the isolation gaseous ring, further prevent that the outside air from getting into the furnace chamber, guarantee the stability of air current in the wire drawing furnace, thereby guarantee the quality of wire drawing, solved the optical fiber perform that the external diameter fluctuation is big and be difficult to the technological problem sealed. However, the temperature-resistant flexible sealing gasket of the patent is directly contacted with a product and rubs at high temperature, so that scraps are easily left on the product, and the quality of the product is influenced.

Chinese patent, publication number CN207862191U discloses a retractable optical fiber perform wire drawing furnace, and the sealing device of this patent includes the sealing cover, the upper portion of this sealing cover with the stick hanging mechanism fixed, and the lower part corresponding to go up the position of fire door with extend stove furnace body coupling, this structure leads to optical fiber perform to go up excellent operation complicacy, carries out unable direct observation in telescopic sleeve, probably leads to going up excellent operation failure.

Chinese patent, publication No. CN203728719U, discloses a sealing device for an optical fiber drawing furnace, which needs to hoist an optical fiber preform to the drawing furnace for hanging, and has low efficiency, more energy consumption, larger device and more occupied space.

The core rod extension process is a process of heating and melting isometric change, and is a physical change, and the process needs to produce a product with stable diameter and good surface quality (without impurities and oxidation), so the process needs to be carried out in a scene with stable temperature and low oxygen content, but the diameter of the product after the core rod extension fluctuates, and the large end inevitably appears at the extension starting position, so that a device with an arbitrarily adjustable sealing port and good sealing performance needs to be designed.

SUMMERY OF THE UTILITY MODEL

For solving the technical problem that exists among the prior art, the utility model aims to provide an optical fiber perform extends automatic sealing device of fire door.

In order to realize the above purpose, reach above-mentioned technological effect, the utility model discloses a technical scheme be:

the utility model provides an optical fiber perform extends automatic sealing device of fire door, is including setting up in the last fire door telescope tube sealing device who extends the stove top and setting up in the lower fire door hole shrink expansion sealing device who extends the stove below, go up the telescopic tube sealing device of fire door telescope tube and include the telescopic tube of two at least coaxial settings, be located the telescopic tube of the innermost and run through the inside and two synchronous vertical reciprocating motion of extension stove, have relative motion between two adjacent telescopic tube, go up the telescopic tube sealing device of fire door telescope tube and can extend automatically and shorten, hole shrink expansion sealing device can open automatically and contract under the lower fire door.

Further, go up burner port telescopic tube sealing device and include three telescopic tube, by outer graphite sleeve, well graphite sleeve and interior graphite sleeve to interior being outer graphite sleeve in proper order, well graphite sleeve upper end and interior graphite sleeve upper end set up the step respectively, and interior graphite sleeve can be in the inside vertical reciprocating motion of well graphite sleeve, and interior graphite sleeve's step and well graphite sleeve inner wall are laminated all the time, and well graphite sleeve can be in the inside vertical reciprocating motion of outer graphite sleeve, and well graphite sleeve's step and outer graphite sleeve inner wall are laminated all the time, and outer graphite sleeve upper end bore is greater than the diameter of upper handle and is less than the diameter of plug.

Further, hole shrink expansion sealing device under lower fire door is including the diameter testing arrangement and the mechanical iris structure of shrink expansion that from top to bottom set gradually, diameter testing arrangement links to each other with PLC, the maximum bore of the mechanical iris structure of shrink expansion is greater than the diameter of plug.

Furthermore, the lower end of the inner graphite sleeve extending out of the interior of the extension furnace is sequentially provided with a diameter measuring point position and a contraction and expansion mechanical iris structure from top to bottom, and the diameter measuring point position is provided with a diameter testing device.

Furthermore, a lower clamp is arranged below the iris structure of the contraction and expansion machine, and an upper clamp is arranged above the extension furnace.

Furthermore, the mechanical iris structure of contraction and expansion comprises an iris mechanical structure, a driving belt, a small synchronous belt pulley and a motor, wherein the maximum caliber of the iris mechanical structure is larger than the maximum diameter of a core layer product, the motor is installed at the rotating shaft of the small synchronous belt pulley, a large coaxial synchronous belt pulley is arranged outside the iris mechanical structure, the large synchronous belt pulley is connected with the small synchronous belt pulley through the driving belt, and the iris mechanical structure can be contracted or expanded.

The utility model discloses an automatic sealing device of optical fiber perform extension fire door carries out sealed step and does:

welding an upper handle and a lower handle at the upper end and the lower end of the core rod respectively, wherein the total length of the core rod, the upper handle and the lower handle is marked as L1;

the method comprises the following steps that an extension furnace and an upper clamp are lifted to a height higher than L1, a plurality of high-temperature-resistant soft material rings are placed at the position of the outermost small aperture of an upper furnace mouth telescopic sleeve sealing device, a lower handle of a core rod is clamped on a lower clamp below the extension furnace, when the extension furnace and the upper clamp are lowered, the core rod penetrates through the extension furnace and jacks up a telescopic sleeve of the upper furnace mouth telescopic sleeve sealing device due to the fact that the diameter of the core rod is larger than the aperture of the upper furnace mouth telescopic sleeve sealing device, the upper furnace mouth telescopic sleeve sealing device automatically extends or is shortened by gravity according to the length of the core rod, the extension furnace and the upper clamp stop after the extension furnace and the upper clamp are lowered to a proper position, an upper handle is clamped on the upper clamp, a contraction and expansion mechanical iris structure automatically adjusts to the corresponding aperture according to the diameter value of the core rod tested by a diameter testing device, then, the extension furnace and the upper clamp move upwards, the movement speed of the extension furnace is larger than the movement speed of the upper clamp, the distance between the extension furnace and the upper clamp is close, the upper clamp, the upper furnace and the upper clamp automatically shortens the upper furnace due to the gravity, the contraction and expansion mechanical iris sealing device automatically adjusts the diameter of the extension furnace according to the diameter of the extension furnace and the movement speed of the extension furnace by gravity; the inert gas positive pressure is maintained in the extension furnace in the whole operation process.

Furthermore, the aperture change of the mechanical iris structure of contraction and expansion is adjusted by controlling the rotating speed of the motor, and the method specifically comprises the following steps:

the motor is arranged at the rotating shaft of the small synchronous belt pulley, the large synchronous belt pulley is coaxially arranged outside the iris mechanical structure, and the large synchronous belt pulley is connected with the small synchronous belt pulley through a driving belt; when the motor is rotatory, little synchronous pulley synchronous revolution, and then drive big synchronous pulley and rotate, establish the rotational speed of motor and be n, it is the same with little synchronous pulley's rotational speed, and the rotational speed n's of motor calculation step is:

measuring the diameter of the core rod by a diameter testing device, and recording the diameter as d1; the final diameter of the iris after mechanical structure adjustment is recorded as d3, and d3= d1+2;

the minimum diameter of the iris mechanical structure is recorded as d2, the gear ratio of the small synchronous pulley to the large synchronous pulley is i, the rotating speed of the large synchronous pulley is recorded as n1, n1= n/i, the ratio i1 of the rotating speed n1 of the large synchronous pulley to the diameter increase value delta d of the iris mechanical structure is n1, n 1/delta d = i1, namely delta d = n1/i1, the diameter of the iris mechanical structure is adjusted by controlling the rotating speed of the motor, d3= delta d + d2= n1/i1+ d2= n/(i 1) + d2, and the rotating speed of the motor is finally calculated.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the device operation is simple, need not carry out other extra operations to the plug, goes up furnace mouth telescope tube sealing device and can extend automatically and shorten, and hole shrink expansion sealing device can open automatically and contract under the lower furnace mouth, has improved work efficiency.

2. The aperture of the contraction and expansion mechanical iris structure is automatically adjusted according to a test result, the contraction and expansion mechanical iris structure is closer to a circular shape, and a smaller gap can be reserved, so that the sealing effect is ensured, oxygen is reduced from entering, the service life of a graphite piece is prolonged, and the risk of surface oxidation of a product is reduced.

3. The reserved apertures at the upper part and the lower part are small, so that the heat in the furnace can be favorably reserved, the stability of a temperature field in the furnace is ensured, and the diameter of the core rod can be favorably controlled.

4. In the whole operation process, the upper part and the lower part are sealed without contacting with a large area of a core rod product, and the upper furnace mouth telescopic sleeve sealing device only contacts with the upper handle of the auxiliary material, so that the generation of impurities is avoided, and the product quality is guaranteed.

5. The upper sealing device and the lower sealing device are small in space structure, long sleeve type sealing is avoided, and space utilization rate is improved.

Drawings

FIG. 1 is a schematic structural view of the core rod, the upper handle and the lower handle of the present invention;

FIG. 2 is a schematic view of the present invention;

fig. 3 is a schematic structural view of the upper tuyere expansion sleeve sealing device of the present invention after three expansion sleeves are completely jacked up;

FIG. 4 is a schematic structural view of the upper tuyere telescopic sleeve sealing device according to the present invention when three telescopic sleeve portions are jacked up;

fig. 5 is a schematic structural view of the mandrel of the present invention after being stretched and when the three telescopic sleeves are not jacked up;

FIG. 6 is a schematic structural view of the high temperature resistant soft material ring of the present invention;

fig. 7 is a schematic structural view of the mechanical structure of the iris of the present invention;

FIG. 8 is a schematic structural view of the iris mechanical structure and the large synchronous pulley of the present invention;

fig. 9 is a schematic structural view of the iris structure of the contraction and expansion machine of the present invention.

Detailed Description

The present invention is described in detail below to enable the advantages and features of the present invention to be more easily understood by those skilled in the art, thereby making more clear and definite definitions of the scope of the present invention.

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

As shown in fig. 1 to 9, an automatic sealing device for an extension furnace mouth of an optical fiber preform rod is aimed at a mandrel 1 with upper and lower ends respectively welded with a clamping handle with a fixed diameter, the clamping handle at the upper end of the mandrel 1 is marked as an upper handle 2, the clamping handle at the lower end of the mandrel 1 is marked as a lower handle 3, the device comprises an upper furnace mouth telescopic sleeve sealing device 4, an upper clamp 5 and a lower furnace mouth lower hole contraction and expansion sealing device, the upper furnace mouth telescopic sleeve sealing device 4 is arranged above an extension furnace 7, the upper clamp 5 is arranged above the extension furnace 7, the lower furnace mouth lower hole contraction and expansion sealing device is arranged below the extension furnace 7, and the upper furnace mouth telescopic sleeve sealing device 4 can realize expansion according to the diameter and the length of the mandrel 1.

Go up fire door telescope tube sealing device 4 and include two at least coaxial arrangement's telescope tube, be located the telescope tube of innermost and run through and extend stove 7 inside and the synchronous vertical reciprocating motion of the two, have relative motion between two adjacent telescope tube, go up fire door telescope tube sealing device 4 and can realize automatic extension or receive gravity and shorten according to the diameter and the length of plug 1.

Hole shrink expansion sealing device under lower fire door is including the diameter testing arrangement and the mechanical iris structure of shrink expansion 9 that from top to bottom set gradually, and diameter testing arrangement links to each other with PLC, and the mechanical iris structure of shrink expansion 9 can be according to diameter value automatic adjustment of the plug 1 of diameter testing arrangement test to corresponding aperture size, realizes shrinking and expanding, and the mechanical iris structure of shrink expansion 9 below is provided with anchor clamps 10 down.

Specifically, mechanical iris structure 9 of shrink expansion includes iris mechanical structure 91, drive belt 92, little synchronous pulley 93 and motor, iris mechanical structure 91's maximum bore is greater than the maximum diameter of sandwich layer product, the motor is installed in little synchronous pulley 93's pivot department, iris mechanical structure 91 outside sets up coaxial big synchronous pulley 94, link to each other through driving belt 92 between this big synchronous pulley 94 and the little synchronous pulley 93, in the use, through the diameter testing arrangement diameter of test sandwich layer product and with the test result upload to corresponding PLC in handle, PLC gives the motor instruction according to test diameter and aperture change law, the motor rotates corresponding value and drives iris mechanical structure 91 shrink or expand to the target aperture.

An automatic sealing method for an optical fiber preform extension furnace mouth comprises the following steps:

setting the upper end and the lower end of a core rod 1 to be respectively welded with a section of clamping handle, wherein the clamping handle at the upper end of the core rod 1 is marked as an upper handle 2, the clamping handle at the lower end of the core rod 1 is marked as a lower handle 3, and the total length of the core rod 1, the upper handle 2 and the lower handle 3 is marked as L1 as shown in figure 1;

the method comprises the steps of raising an extension furnace 7 and an upper clamp 5 to a height higher than L1, placing 3-4 high-temperature-resistant soft material rings 6 at the position of the outermost small aperture of an upper furnace mouth telescopic sleeve sealing device 4, clamping a lower handle 3 of a core rod 1 on a lower clamp 10 below the extension furnace 7, then lowering the extension furnace 7 and the upper clamp 5, enabling the core rod 1 to automatically extend or shorten due to gravity according to the fact that the diameter of the core rod 1 is larger than that of the upper furnace mouth telescopic sleeve sealing device 4 after penetrating through the extension furnace 7, stopping after the extension furnace 7 and the upper clamp 5 are lowered to proper positions, clamping the upper handle 2 on the upper clamp 5, automatically adjusting a contraction and expansion mechanical iris structure 9 to the corresponding aperture size according to the diameter value of the core rod 1 tested by a diameter testing device, then preheating the core rod 1, moving the extension furnace 7 and the upper clamp 5 upwards until the movement speed of the extension furnace 7 is larger than that of the upper clamp 5, continuously adjusting the movement speed of the extension furnace 7 and the extension furnace mouth telescopic sleeve sealing device, continuously adjusting the diameter of the extension furnace 1, and the extension furnace mouth telescopic sleeve sealing device 7, and automatically adjusting the diameter of the extension furnace 7 and the extension furnace 1 according to the iris structure of the extension furnace. The positive pressure of inert gas is kept in the furnace in the whole operation process, and the reliability of the whole device is enhanced.

Let the distance between the diameter measuring position and the sealing position of the mechanical iris contraction and expansion structure 9 be L2, the movement speed of the extension furnace 7 be V, and the time when the mechanical iris contraction and expansion structure 9 rises to the diameter measuring position be t, t = L2/V. Let the rotation speed of the motor be n, which is the same as the rotation speed of the small synchronous pulley 93, and the calculation step of the rotation speed n of the motor is as follows:

measuring the diameter of the core rod 1 by a diameter testing device, and recording the diameter as d1; the adjusted final diameter of the iris mechanical structure 91 is denoted as d3, d3= d1+2;

the minimum diameter of the iris mechanical structure 91 is represented as d2, the gear ratio of the small synchronous pulley 93 to the large synchronous pulley 94 is i, the rotation speed of the large synchronous pulley 94 is represented as n1, n1= n/i, the ratio i1 of the rotation speed n1 of the large synchronous pulley 94 to the diameter increase value Δ d of the iris mechanical structure 91, n1/Δ d = i1, that is, Δ d = n1/i1, the diameter of the iris mechanical structure 91 is adjusted by controlling the rotation speed of the motor, d3= Δ d + d2= n1/i1+ d2= n/(i 1) + d2, and the rotation speed of the motor is finally calculated.

Example 1

As shown in fig. 1-9, an automatic sealing device for an optical fiber perform extension furnace mouth is a core rod 1, the upper end and the lower end of which are respectively welded with a clamping handle with a fixed diameter, the clamping handle at the upper end of the core rod 1 is an upper handle 2, the clamping handle at the lower end of the core rod 1 is a lower handle 3, the automatic sealing device comprises an upper furnace mouth telescopic sleeve sealing device 4 arranged above an extension furnace 7 and a lower furnace mouth hole contraction and expansion sealing device arranged below the extension furnace 7, the upper furnace mouth telescopic sleeve sealing device 4 comprises three coaxially arranged telescopic sleeves, an outer graphite sleeve 41, a middle graphite sleeve 42 and an inner graphite sleeve 43 are sequentially arranged from outside to inside, the caliber of the upper end of the outer graphite sleeve 41 is larger than the diameter of the upper handle 2 and smaller than the diameter of the core rod 1, the outer graphite sleeve 41 is sleeved outside the middle graphite sleeve 42, the middle graphite sleeve 42 is sleeved outside the inner graphite sleeve 43, the upper end of the middle graphite sleeve 42 and the upper end of the inner graphite sleeve 43 are respectively provided with steps, the inner graphite sleeve 43 can vertically move inside the middle graphite sleeve 42 and the inner graphite sleeve 42 can always move along with the inner wall of the inner graphite sleeve 42, and the inner graphite sleeve 41 can move synchronously with the inner wall of the inner graphite sleeve 42, and the inner graphite sleeve 7, the inner wall of the inner graphite sleeve can move synchronously.

The lower furnace mouth lower hole contraction and expansion sealing device comprises a diameter testing device and a contraction and expansion mechanical iris structure 9, the lower end, extending out of the interior of the extension furnace 7, of the inner graphite sleeve 43 is sequentially provided with a diameter measuring point position 8 and the contraction and expansion mechanical iris structure 9 from top to bottom, the diameter measuring point position 8 is provided with the diameter testing device, the diameter of the core rod 1 is measured through the diameter testing device, data are fed back to the PLC, and the maximum caliber of the contraction and expansion mechanical iris structure 9 is larger than the diameter of the core rod 1.

An upper clamp 5 is arranged above the extension furnace 7, and a lower clamp 10 is arranged below the iris structure 9 of the contraction and expansion machine.

An automatic sealing method for an optical fiber preform extension furnace mouth comprises the following steps:

setting the upper end and the lower end of a core rod 1 to be respectively welded with a section of clamping handle, marking the clamping handle at the upper end of the core rod 1 as an upper handle 2, marking the clamping handle at the lower end of the core rod 1 as a lower handle 3, and marking the total length of the core rod 1, the upper handle 2 and the lower handle 3 as L1 as shown in figure 1;

the method comprises the steps of raising an extension furnace 7 and an upper clamp 5 to a height higher than L1, placing 3-4 high-temperature-resistant soft material rings 6 at the outermost small aperture of an upper furnace mouth telescopic sleeve sealing device 4, clamping a lower handle 3 of a core rod 1 on a lower clamp 10 below the extension furnace 7, then lowering the extension furnace 7 and the upper clamp 5, jacking a first layer (namely an inner graphite sleeve 43) of the upper furnace mouth telescopic sleeve sealing device 4 due to the fact that the diameter of the core rod 1 is larger than that of the upper furnace mouth telescopic sleeve sealing device 4 after the core rod 1 passes through the extension furnace 7, if the core rod 1 is longer, jacking a second layer (namely a middle graphite sleeve 42), automatically extending the upper furnace mouth telescopic sleeve sealing device 4 according to the length of the core rod 1 or shortening the core rod due to gravity, stopping after the extension furnace 7 and the upper clamp 5 descend to a proper position, clamping the upper handle 2 on the upper clamp 5, automatically adjusting a contraction and expansion mechanical iris structure 9 to the diameter value of the core rod 1 tested by a diameter testing device to a corresponding aperture size, then starting to preheat the extension furnace 1, moving the extension furnace 7 and the upper clamp 5 until the extension furnace mouth and the extension furnace mouth move towards the upper clamp 5, and the extension furnace mouth automatically adjusting the extension furnace mouth and finishing the extension furnace mouth and the extension furnace mouth expansion speed of the extension furnace and the extension furnace mouth of the extension furnace according to the iris structure of the iris structure 9. The positive pressure of the inert gas is kept in the furnace in the whole operation process, so that the reliability of the whole device is enhanced.

Let the distance between the diameter measuring position and the sealing position of the mechanical iris contraction and expansion structure 9 be L2, the movement speed of the extension furnace 7 be V, and the time when the mechanical iris contraction and expansion structure 9 rises to the diameter measuring position be t, t = L2/V. Let the rotation speed of the motor be n, which is the same as the rotation speed of the small synchronous pulley 93, and the calculation step of the rotation speed n of the motor is as follows:

measuring the diameter of the core rod 1 by a diameter testing device, and recording the diameter as d1; the adjusted final diameter of the iris mechanical structure 91 is recorded as d3, d3= d1+2;

the minimum diameter of the iris mechanical structure 91 is represented as d2, the gear ratio of the small synchronous pulley 93 to the large synchronous pulley 94 is i, the rotation speed of the large synchronous pulley 94 is represented as n1, n1= n/i, the ratio i1 of the rotation speed n1 of the large synchronous pulley 94 to the diameter increase value Δ d of the iris mechanical structure 91, n1/Δ d = i1, that is, Δ d = n1/i1, the diameter of the iris mechanical structure 91 is adjusted by controlling the rotation speed of the motor, d3= Δ d + d2= n1/i1+ d2= n/(i 1) + d2, and the rotation speed of the motor is finally calculated.

The utility model discloses not the part or the structure of concrete description adopt prior art or current product can, do not do here and describe repeatedly.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all utilize the equivalent structure or equivalent flow transformation that the content of the specification does, or directly or indirectly use in other related technical fields, all including in the same way the patent protection scope of the present invention.

Claims (6)

1. The utility model provides an optical fiber perform extends automatic sealing device of fire door, its characterized in that, including setting up in the last fire door telescope tube sealing device who extends the stove top and setting up in the lower fire door hole shrink expansion sealing device who extends the stove below, go up the fire door telescope tube sealing device and include the telescope tube of two at least coaxial settings, be located the telescope tube of the innermost and run through and extend the stove inside and the vertical reciprocating motion of the two synchronization, have relative motion between two adjacent telescope tubes, go up the fire door telescope tube sealing device and can extend and shorten automatically, hole shrink expansion sealing device can open automatically and contract under the lower fire door hole.

2. The automatic sealing device of the optical fiber preform extending furnace mouth according to claim 1, wherein the upper furnace mouth telescopic sleeve sealing device comprises three telescopic sleeves, an outer graphite sleeve, a middle graphite sleeve and an inner graphite sleeve are sequentially arranged from outside to inside, steps are respectively arranged at the upper end of the middle graphite sleeve and the upper end of the inner graphite sleeve, the inner graphite sleeve can vertically reciprocate inside the middle graphite sleeve, the steps of the inner graphite sleeve are always attached to the inner wall of the middle graphite sleeve, the middle graphite sleeve can vertically reciprocate inside the outer graphite sleeve, the steps of the middle graphite sleeve are always attached to the inner wall of the outer graphite sleeve, and the caliber of the upper end of the outer graphite sleeve is larger than the diameter of the upper handle and smaller than the diameter of the core rod.

3. The apparatus of claim 1, wherein the apparatus for sealing the lower opening of the furnace by shrinkage and expansion comprises a diameter measuring device and a mechanical iris shrinkage and expansion structure, the diameter measuring device is connected to the PLC, and the maximum diameter of the mechanical iris shrinkage and expansion structure is greater than the diameter of the mandrel.

4. The automatic sealing device for the furnace mouth of the optical fiber preform rod extension furnace of claim 2, wherein the lower end of the inner graphite sleeve extending out of the interior of the extension furnace is provided with a diameter measuring point position and a contraction and expansion mechanical iris structure in sequence from top to bottom, and the diameter measuring point position is provided with a diameter testing device.

5. The apparatus of claim 3 or 4, wherein a lower jig is provided below the iris structure of the contraction and expansion machine, and an upper jig is provided above the elongating furnace.

6. The automatic sealing device of claim 3, wherein the mechanical iris structure comprises a mechanical iris structure, a driving belt, a small synchronous pulley and a motor, the maximum diameter of the mechanical iris structure is greater than the maximum diameter of the core product, the motor is mounted at the rotating shaft of the small synchronous pulley, a large synchronous pulley is coaxially arranged outside the mechanical iris structure, the large synchronous pulley is connected with the small synchronous pulley through the driving belt, and the mechanical iris structure can be contracted or expanded.

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