Electric heating furnace for preform and furnace mouth sealing device thereof

Abstract

The utility model provides an electric heating furnace for a preform and a furnace mouth sealing device of the electric heating furnace. The furnace mouth sealing device comprises a graphite heat insulation sheet, a positioning pin, a rotating disc, a linear guide rail and a driving mechanism, the driving mechanism is connected with the rotating disc to drive the rotating disc to rotate relative to a furnace top plate or a furnace bottom plate, a plurality of arc-shaped sliding grooves are evenly distributed in the circumferential direction of the rotating disc, and the positioning pin penetrates through the graphite heat insulation sheet and is fixedly connected with the graphite heat insulation sheet. The head of the positioning pin penetrates through the arc-shaped sliding groove, the bottom of the positioning pin is contained on the linear guide rail of the furnace top plate or the furnace bottom plate, the multiple graphite heat insulation sheets are enclosed, and the middle portions of the graphite heat insulation sheets jointly form a through hole for a preform to penetrate through. According to the furnace mouth sealing device, the rotating disc rotates to drive the positioning pin to rotate, so that the purpose of adjusting the diameter of the inner hole defined by the graphite heat insulation sheets is achieved, the sealing requirements of preforms with different diameters can be met, the heat loss of the furnace mouth is effectively reduced, and components above or below the furnace mouth are protected from being influenced by high temperature.

Description

Technical Field

[0001] The utility model relates to the technical field of core-taking devices, in particular to an electric heating furnace for a preform and a furnace mouth sealing device thereof. Background Art

[0002] At present, the main preparation process routes of optical fiber preforms are as follows: 1) A loose body (Soot) is prepared by the VAD (axial vapor deposition) technology. The loose body is subjected to high-temperature sintering to remove hydroxyl and impurities, and after melting and stretching to extend, a core rod is obtained. Then, the OVD (outside tube vapor deposition) is used to deposit a cladding on the outer periphery of the core rod, and an optical fiber preform is obtained through subsequent processes such as dehydration and sintering; 2) The RIC (Rod In Cylinder) process route is adopted. The core rod is prepared by PCVD (plasma chemical vapor deposition) or VAD, and then the core rod is nested into a sleeve, and finally an optical fiber preform is obtained through high-temperature melting and shrinking. In the process of preparing optical fiber preforms, quartz tubes, or fiber drawing, high-temperature melting is required, and usually an electric heating furnace is used as a heat source to realize the melting and softening of optical fiber preforms or quartz tubes.

[0003] In the patent CN104710106A, the preform is heated and melted and shrunk with medium-frequency induction heating as the heat source, and the sealing of its heating furnace mouth uses a quartz ring with a fixed size, which cannot achieve continuous variable diameter adjustment and cannot realize the sealing of preforms with different specifications and sizes; in the patent CN108975678A, a pair of swinging graphite shutters are used to achieve heat insulation and sealing, and continuous adjustment cannot be achieved either. Summary of the Utility Model

[0004] The main purpose of the utility model is to provide an electric heating furnace for a preform and a furnace mouth sealing device thereof, aiming to realize continuous adjustability of the diameter of the heating furnace mouth seal.

[0005] To achieve the above purpose, the utility model provides a furnace mouth sealing device for an electric heating furnace for a preform, including a graphite heat insulation sheet, a positioning pin, a rotating disk, a linear guide rail, and a driving mechanism. Among them,

[0006] The rotating disk is installed on the furnace top plate and / or the furnace bottom plate of the electric heating furnace. The driving mechanism is connected to the rotating disk to drive it to rotate relative to the furnace top plate or the furnace bottom plate. A plurality of arc-shaped chutes are evenly distributed in the circumferential direction of the rotating disk. The positioning pin passes through the graphite heat insulation sheet and is fixedly connected to it. The head of the positioning pin passes through the arc-shaped chute, and the bottom of the positioning pin is accommodated on the linear guide rail of the furnace top plate or the furnace bottom plate. A plurality of graphite heat insulation sheets enclose and jointly form a through hole for the preform to pass through in the middle.

[0007] Preferably, the positioning holes on the positioning pin and the graphite heat insulation sheet are in interference fit.

[0008] Preferably, the rotating disk is a disk structure with a through hole in the middle, and a guiding mechanism for guiding its rotation is arranged on the outer peripheral side of the rotating disk.

[0009] Preferably, the guiding mechanism includes a guiding wheel shaft fixed to the furnace top plate or the furnace bottom plate, a bearing sleeved on the top of the guiding wheel shaft, and a guiding wheel sleeved outside the bearing.

[0010] Preferably, a guiding groove is formed on the side surface of the guiding wheel to contact with the side surface of the rotating disk.

[0011] Preferably, the rotating disk corresponds to at least two guiding mechanisms.

[0012] Preferably, teeth are arranged on the outer peripheral side of the rotating disk, and the driving mechanism includes a motor and a driving gear fixed on the output shaft of the motor. The driving gear meshes with the teeth of the rotating disk to drive it to rotate.

[0013] Preferably, the mounting base of the motor is fixed to the furnace top plate or the furnace bottom plate.

[0014] Preferably, the graphite heat insulation sheet is in the shape of a triangular plate.

[0015] The present utility model further provides an electric heating furnace for a preform, which includes a furnace top plate and a furnace bottom plate, and the above-mentioned furnace mouth sealing device is installed on the furnace top plate and / or the furnace bottom plate.

[0016] For the furnace mouth sealing device provided by the present utility model, when the rotating disk rotates, the positioning pin is driven to rotate, and then the corresponding graphite heat insulation sheet is driven to move, so as to achieve the purpose of adjusting the diameter of the inner hole formed by enclosing the graphite heat insulation sheet, and further adapt to the sealing requirements of preforms with different diameters, thereby effectively reducing the heat loss at the furnace mouth and protecting the components above or below the furnace mouth from the influence of high temperature. This furnace mouth sealing device also has the advantages of simple structure, stable and reliable operation, low manufacturing cost and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the furnace mouth sealing device of the electric heating furnace for a preform of the present utility model;

[0018] Figure 2 is a schematic structural diagram of the guiding mechanism in the furnace mouth sealing device of the electric heating furnace for a preform of the present utility model;

[0019] Figure 3 is a partial schematic structural diagram of the furnace mouth sealing device of the electric heating furnace for a preform of the present utility model;

[0020] Figure 4 is a schematic structural diagram of the cooperation of the positioning pin with the graphite heat insulation sheet and the linear guide rail in the furnace mouth sealing device of the electric heating furnace for a preform of the present utility model.

[0021] In the figure, 1 - furnace bottom plate, 2 - motor, 3 - graphite heat insulation sheet, 4 - positioning pin, 5 - preform, 6 - driving gear, 7 - guide wheel, 8 - linear guide rail, 9 - driven gear ring, 10 - bearing, 11 - guide wheel shaft.

[0022] The realization, functional features and advantages of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiment

[0023] It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0024] It should be noted that in the description of the present utility model, the orientation or positional relationship indicated by the terms "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] The present utility model provides a furnace mouth sealing device for an electric heating furnace for a preform.

[0026] Referring to Figures 1 to 4 , in this preferred embodiment, a furnace mouth sealing device for an electric heating furnace for a preform includes a graphite heat insulation sheet 3, a positioning pin 4, a rotating disk, a linear guide rail 8 and a driving mechanism. Among them,

[0027] The rotating disk is installed on the furnace top plate and / or the furnace bottom plate 1 of the electric heating furnace. The driving mechanism is connected to the rotating disk to drive it to rotate relative to the furnace top plate or the furnace bottom plate 1. A plurality of arc-shaped chutes are evenly distributed in the circumferential direction of the rotating disk. The positioning pin 4 passes through the graphite heat insulation sheet 3 and is fixedly connected thereto. The head of the positioning pin 4 passes through the arc-shaped chute, and the bottom of the positioning pin 4 is received on the linear guide rail 8 of the furnace top plate or the furnace bottom plate 1. A plurality of graphite heat insulation sheets 3 enclose each other and jointly form a through hole in the middle for the preform to pass through.

[0028] Specifically, the number of arc-shaped chutes is the same as the number of graphite heat insulation sheets 3, and they correspond one by one. Each graphite heat insulation sheet 3 is correspondingly provided with a positioning pin 4. A limiting plate is provided on the head of the positioning pin 4, and the limiting plate is located above the top surface of the rotating disk.

[0029] In this embodiment, the positioning pin 4 and the positioning holes on the graphite heat insulation sheet 3 are in interference fit. In this embodiment, the rotating disk is a disk structure with a through hole in the middle, and a guiding mechanism for guiding its rotation is arranged on the outer peripheral side of the rotating disk. The inner hole of the rotating disk is coaxially arranged with the inlet of the furnace top plate or the furnace bottom plate 1.

[0030] Referring to Figure 2 , this embodiment hereby proposes a specific structure of the guiding mechanism: The guiding mechanism includes a guiding wheel shaft 11 fixed on the furnace top plate or the furnace bottom plate 1, a bearing 10 sleeved on the top of the guiding wheel shaft 11, and a guiding wheel 7 sleeved outside the bearing 10. The cooperation of the bearing 10 and the guiding wheel 7 ensures that the guiding wheel 7 is relative to the guiding wheel shaft 11

[0031] Furthermore, a guiding groove is formed on the side surface of the guiding wheel 7 to contact with the side surface of the rotating disk. The guiding groove limits the rotation of the rotating disk to prevent its position from shifting during rotation, thereby ensuring the accuracy of the moving position of the graphite heat insulation sheet 3. Specifically, the rotating disk corresponds to at least two guiding mechanisms.

[0032] Furthermore, teeth are arranged on the outer peripheral side of the rotating disk (that is to say, the rotating disk is a toothed ring, and the outer peripheral side can be provided with teeth in some parts and no teeth in other parts, and the part without teeth contacts with the guiding wheel 7). The driving mechanism includes a motor 2 and a driving gear 6 fixed on the output shaft of the motor 2. The driving gear 6 meshes with the teeth of the rotating disk to drive its rotation.

[0033] In this embodiment, the mounting base of the motor 2 is fixed on the furnace top plate or the furnace bottom plate 1. The motor 2 is a servo motor. Referring to Figure 4 , the graphite heat insulation sheet 3 is in the shape of an obtuse triangle plate (a corner is cut at one acute angle of the triangle).

[0034] The working principle of this furnace mouth sealing device is as follows: Through the meshing relationship between the driving gear 6 and the driven toothed ring 9 (that is, the rotating disk), the motor 2 works to drive the driven toothed ring 9 to generate a rotational motion, and the rotation angle changes continuously. The rotational motion of the driven toothed ring 9 is converted into a linear motion of the graphite heat insulation sheet 3 along the linear guide rail 8 through the positioning pin 4 and the linear guide rail, thereby realizing the continuous variable diameter of the furnace mouth sealing, and the angular position can be changed arbitrarily, and further effectively reducing the heat loss at the furnace mouth and protecting the components above or below the furnace mouth from high temperature effects.

[0035] The furnace mouth sealing device proposed in this embodiment drives the positioning pin 4 to rotate when the rotating disk rotates, and then drives the corresponding graphite heat insulation sheet 3 to move, so as to achieve the purpose of adjusting the diameter of the inner hole formed by the enclosure of the graphite heat insulation sheet 3, and further can adapt to the sealing requirements of preforms with different diameters, thereby effectively reducing the heat loss at the furnace mouth and protecting the components above or below the furnace mouth from high temperature effects. This furnace mouth sealing device also has the advantages of simple structure, stable and reliable operation, low manufacturing cost, excellent light-shielding and heat-insulating performance, and easy implementation.

[0036] The present utility model further provides an electric heating furnace for a preform.

[0037] In this preferred embodiment, an electric heating furnace for a preform includes a furnace top plate and a furnace bottom plate 1, and a furnace mouth sealing device is installed on the furnace top plate and / or the furnace bottom plate 1. For the specific structure and beneficial effects of the furnace mouth sealing device, refer to the above embodiments and will not be elaborated here. Among them, the furnace top plate and the furnace bottom plate 1 are internally provided with cooling water channels and are circumferentially and uniformly provided with protective gas inlet channels.

[0038] The above are only the preferred embodiments of the present utility model, and do not limit the patent scope of the present utility model accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present utility model.

Claims

1. A furnace mouth sealing device for an electric heating furnace of a preform, characterized in that, It includes a graphite heat insulation sheet, a positioning pin, a rotating disk, a linear guide rail and a driving mechanism. Among them, the rotating disk is installed on the top plate and / or the bottom plate of the electric heating furnace. The driving mechanism is connected to the rotating disk to drive it to rotate relative to the top plate or the bottom plate of the furnace. A plurality of arc-shaped chutes are evenly distributed in the circumferential direction of the rotating disk. The positioning pin passes through the graphite heat insulation sheet and is fixedly connected to it. The head of the positioning pin passes through the arc-shaped chute, and the bottom of the positioning pin is accommodated on the linear guide rail of the top plate or the bottom plate of the furnace. Multiple graphite heat insulation sheets enclose each other and jointly form a through hole in the middle for the preform to pass through.

2. The furnace mouth sealing device of the electric heating furnace for a preform according to claim 1, characterized in that, The positioning hole on the positioning pin and the graphite heat insulation sheet is an interference fit.

3. The furnace mouth sealing device of the electric heating furnace for a preform as described in claim 1, characterized in that, The rotating disk is a disk structure with a through hole in the middle, and a guiding mechanism for guiding its rotation is arranged on the outer peripheral side of the rotating disk.

4. The furnace mouth sealing device of the electric heating furnace for a preform according to claim 3, characterized in that, The guiding mechanism includes a guiding wheel shaft fixed on the top plate or the bottom plate of the furnace, a bearing sleeved on the top of the guiding wheel shaft, and a guiding wheel sleeved outside the bearing.

5. The furnace mouth sealing device of the electric heating furnace for the preform according to claim 4, characterized in that, A guiding groove is formed on the side surface of the guiding wheel to contact the side surface of the rotating disk.

6. The furnace mouth sealing device of the electric heating furnace for a preform according to claim 4, characterized in that, The rotating disk corresponds to at least two guiding mechanisms.

7. The furnace mouth sealing device of the electric heating furnace for a preform according to claim 3, characterized in that, Teeth are arranged on the outer peripheral side of the rotating disk. The driving mechanism includes a motor and a driving gear fixed on the output shaft of the motor. The driving gear meshes with the teeth of the rotating disk to drive it to rotate.

8. The furnace mouth sealing device of the electric heating furnace for a preform according to claim 7, characterized in that, The mounting base of the motor is fixed on the top plate or the bottom plate of the furnace.

9. The furnace mouth sealing device of the electric heating furnace for a preform according to any one of claims 1 to 8, characterized in that, The graphite heat insulation sheet is in the shape of a triangular plate.

10. An electric heating furnace for a preform, characterized in that, It includes a top plate and a bottom plate of the furnace, and the furnace mouth sealing device described in any one of claims 1 to 9 is installed on the top plate and / or the bottom plate of the furnace.

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