Soaking device, vacuum electric melting furnace for preparing quartz glass and technology

Abstract

The invention discloses a soaking device which comprises a supporting piece and a soaking plate. The supporting piece is of an annular structure with a mounting hole formed in the middle. The vapor chamber is an isostatic pressing graphite plate, the vapor chamber is arranged in the mounting hole of the supporting piece, and the edge part of the vapor chamber is connected with the supporting assembly; the vapor chamber comprises a plurality of plate bodies which are spliced in the transverse direction and the longitudinal direction, a step face is arranged at the splicing seam of each plate body to form a boss or a groove, and the bosses and the grooves of every two adjacent plate bodies are connected in a matched and clamped mode. And the adjacent plate bodies are connected through rib plates. The invention also discloses a vacuum electrothermal furnace and an adaptive glass preparation process. The vacuum electric melting furnace has the beneficial effects that the soaking device is introduced into the vacuum electric melting furnace, heat provided by the special-shaped graphite heating body is not directly radiated to the upper surface of crystal powder, but is absorbed and soaked by the isostatic pressing graphite plate with the good heat conductivity coefficient, and then the heat is uniformly radiated to the upper surface of the crystal powder, so that the crystal powder is uniformly melted from top to bottom, and the crystal powder is uniformly melted; the problem of bubbles caused by uneven temperature fields is eliminated, and the quality of quartz glass is improved.

Description

Technical Field

[0001] The invention relates to a heating technology, and in particular to a heat-saturating device, a vacuum electric melting furnace and a process for preparing quartz glass. Background Art

[0002] Quartz glass is a special industrial technical glass composed of a single component of SiO2. It has a series of special properties that cannot be replaced by other materials, such as very low thermal conductivity, excellent resistance to thermal vibration, very high deformation temperature and softening temperature, very low thermal conductivity, very low dielectric loss and optical transmittance in a very wide spectral range from ultraviolet to infrared. It is widely used in modern industrial and high-tech fields such as the semiconductor industry, optical communications, solar energy industry, aerospace, medical and electronics industries, and plays a very important role.

[0003] Fused quartz glass is made by melting crystal powder with electricity as the power source. The crystal powder is placed in a special furnace and heated to 1800-2000℃ and 0.1-10Pa vacuum in a vacuum furnace to melt and generate quartz glass. The main macroscopic defect of fused quartz glass is bubbles: due to the uneven temperature distribution of the vacuum melting furnace, the local temperature is low, the crystal powder has not yet completely transformed, and the temperature rise process is too fast, which will cause it to be encapsulated by the glass melt and produce bubbles; the graphite insulation layer of the vacuum melting furnace is exposed directly above the crystal powder. As the number of furnaces used increases, there is a certain probability that the process attachments on the insulation layer will be directly transferred into the crystal powder to form inclusion bubbles. Bubbles have a great impact on the performance of quartz glass. Summary of the invention

[0004] The object of the present invention is to provide a heat-saturating device, an electric melting furnace and a process for preparing quartz glass in view of the deficiencies of the prior art, so as to improve the quality of quartz glass.

[0005] The technical solution adopted by the present invention is: a heat-spreading device, comprising a support member and a heat-spreading plate;

[0006] The support member is a ring-shaped structure with a mounting hole in the middle;

[0007] The heat spreader is an isostatically pressed graphite plate, which is arranged in the mounting hole of the support component, and the edge of the heat spreader is connected to the support component.

[0008] According to the above scheme, the heat spreader includes multiple plates spliced ​​in the horizontal and vertical directions. Each plate is provided with a step surface at the joint to form a boss or a groove. The bosses and grooves of two adjacent plates cooperate with each other to be connected; the adjacent plates are connected by rib plates.

[0009] According to the above solution, the support member includes a support block and a connecting plate;

[0010] There are multiple support blocks, which are arranged in sequence and connected by connecting plates, and the middle part is surrounded to form a mounting hole;

[0011] The heat spreader is arranged in the mounting hole, and the edge of the heat spreader overlaps the inner edge of the support block.

[0012] According to the above scheme, the support block includes a radially inward support portion, a radially outward extension portion, a vertically upward connection portion and a vertically downward limit portion; the connection portions of two adjacent support blocks are connected by a connecting plate; the support portions of each support block are enclosed to form a mounting hole, and the edge of the heat spreader is overlapped on the support portion of the support block; the connecting plate is an isostatically pressed graphite plate.

[0013] The present invention also discloses a vacuum electric melting furnace for preparing quartz glass, comprising a furnace body, a furnace cover, a heating device and the above-mentioned heat equalizing device, wherein the bottom and surrounding of the furnace body are surrounded, and the furnace cover is arranged on the top of the furnace body; the heating device is installed at the lower part of the furnace cover; the heat equalizing device is located below the heating device, and the support member of the heat equalizing device is overlapped on the top of the furnace body and enclosed with the furnace body to form a cavity, and the cavity is filled with crystal powder; the bottom of the furnace cover is arranged on the extension part of the support member.

[0014] According to the above scheme, the furnace body includes a bottom structure and a side structure; the bottom structure includes a steel bottom plate and bottom bricks laid on the steel bottom plate;

[0015] The side structure includes a steel cage and inner insulation brick layers respectively arranged inside the steel cage, and zirconium oxide balls are filled between the steel cage and the inner insulation brick layer; the bottom of the steel cage is arranged on a steel bottom plate, and the bottom of the inner insulation brick layer is arranged on the bottom brick; an outer insulation brick layer is arranged on the top outer side of the steel beam;

[0016] The support part of the heat equalizing device support is arranged on the top of the inner insulation brick layer, the extension part of the support is overlapped on the top of the outer insulation brick layer, and the limiting part of the support is inserted between the inner insulation brick layer and the outer insulation brick layer.

[0017] According to the above scheme, zirconia balls are filled between the inner insulation brick layer, the outer insulation brick layer and the steel cage.

[0018] The present invention also adopts a quartz glass preparation process based on the vacuum electric melting furnace as described above, the process comprising:

[0019] Fill the furnace body of the device with quartz sand, and then install a heat-saturating device;

[0020] Vacuuming;

[0021] Start the heating device to heat up, so that the temperature in the furnace rises to the set temperature, then keeps the temperature and maintains the vacuum state;

[0022] Lower the temperature in the furnace to the set temperature and remove the stress inside the quartz ingot;

[0023] The quartz ingot is then cooled to room temperature.

[0024] According to the above scheme, the heating rate is 180℃ / h.

[0025] According to the above scheme, after the temperature in the furnace is reduced to 1300-1350°C, the internal stress of the quartz ingot is relieved.

[0026] The beneficial effects of the present invention are:

[0027] 1. The heat spreader device of the present invention has a detachable connection between the heat spreader and the support member, which is convenient for assembly and hoisting. At the same time, the heat spreader is made of multiple plates spliced ​​together and fixed with ribs. This design is simple and reliable, and the number of plates can be flexibly adjusted according to the actual size of the device.

[0028] 2. The present invention introduces a heat equalizing device into the vacuum electric melting furnace for preparing quartz glass. The heat provided by the special-shaped graphite heating element is not directly radiated to the upper surface of the crystal powder, but is absorbed and equalized by the isostatically pressed graphite plate with good thermal conductivity, and then uniformly radiated to the upper surface of the crystal powder, so that it is uniformly melted from top to bottom, eliminating the bubble problem caused by uneven temperature field and improving the quality of quartz glass.

[0029] 3. The structure of the heat spreader and the support ring designed in the present invention isolates the crystal powder from the upper furnace cover of the vacuum electric melting furnace and its heating element and insulation layer, reduces the deposition of high-temperature volatile silicon dioxide gas on the relatively loose and easily attached surface of the graphite thermal insulation adhesive, and extends the service life of the thermal insulation adhesive; at the same time, harmful impurities such as graphite particles, attachments, and particles in the hard-to-clean parts of the upper furnace cover of the graphite thermal insulation adhesive are also blocked by the heat spreader and will not fall into the crystal powder below, thereby avoiding bubbles caused by foreign particles and further improving the quality of the adapted glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the heat equalizing device in the present invention.

[0031] Figure 2 A top view of the heat spreader.

[0032] Figure 3 This is the front view of the heat sink.

[0033] Figure 4 Schematic diagram of the exploded view of the heat spreader.

[0034] Figure 5 A schematic diagram of the support.

[0035] Figure 6 A top view of the support member.

[0036] Figure 7 for Figure 6 AA section view.

[0037] Figure 8 Schematic diagram of the connection between two support blocks.

[0038] Fig. 9 A schematic diagram of the structure of the support block.

[0039] Fig.10 The front view of the support block.

[0040] Fig.11 This is the left side view of the support block.

[0041] Fig.12 A top view of the support block.

[0042] Fig.13 This is a schematic diagram of the overall structure of a vacuum electric melting furnace.

[0043] Fig.14 It is a schematic diagram of the connection between the heat equalizing device and the furnace body.

[0044] In the figure, 1-1, furnace cover, 1-2, graphite heating element, 2-1, heat spreader, 2-10, lifting ear, 2-11, heat spreader one, 2-12, heat spreader two, 2-13, heat spreader three, 2-14, heat spreader four, 2-15, heat spreader five, 2-16, heat spreader six, 2-17, heat spreader seven, 2-18, rib plate one, 2-19, rib plate two, 2-2, support member, 2-21, support block, 2-22, connecting plate; 2-23, connecting part, 2-24, limiting part, 2-25, extension part, 2-26, supporting part, 2-27, mounting hole, 3-1, steel cage, 3-2, inner insulation brick layer, 3-3, outer insulation brick layer, 3-4, bottom brick, 3-5, steel bottom plate. DETAILED DESCRIPTION

[0045] In order to better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0046] like Figures 1 to 3 A heat-saturating device is shown, specifically a heat-saturating device for fused quartz glass process,

[0047] It includes a support member 2-2 and a heat spreader 2-1;

[0048] The support member 2-2 is a ring-shaped structure with a mounting hole in the middle;

[0049] The heat spreader 2-1 is an isostatically pressed graphite plate, and the heat spreader 2-1 is arranged in the mounting hole of the support member 2-2, and the edge of the heat spreader 2-1 is connected to the support assembly.

[0050] In the present invention, the shapes of the support member 2-2 and the heat spreader 2-1 can be designed according to actual needs. For example, if the heat spreader 2-1 is designed to be square or round, the mounting hole of the support member 2-2 can be designed to be square or round accordingly; the support member 2-2 as a whole can be designed to be a circular ring structure or a square ring structure.

[0051] In the present invention, the heat spreader 2-1 includes a plurality of plates joined in the horizontal and vertical directions, and the edges of adjacent plates are connected by snapping; the adjacent plates are connected by ribs. Specifically, the edges of two plates adjacent in the horizontal direction or connected in the vertical direction are snapped by bosses and grooves, that is, the edge of one plate is designed with a groove, and the corresponding edge of the other plate is designed with a boss that matches the groove.

[0052] In this embodiment, the heat spreader 2-1 is a circular plate with a diameter of 1900 mm and a thickness of 25 mm. Figure 4 The plate body 1 2-11, plate body 2-12, plate body 3 2-13, plate body 4 2-14, plate body 5 2-15, plate body 6 2-16, and plate body 7 2-17 are spliced ​​and connected; there are two plates 1-11, and one plate each. The material of each plate is isostatic graphite, with an ash content of ≤5ppm; a step surface is provided at the joint of each plate to form a boss or a groove, and the bosses and grooves of two adjacent plates are matched and connected with each other to ensure that the shape of the spliced ​​components is complete and the size is accurate. Among them, plate body seven 2-17 and plate body six 2-16 are rectangular plates, which are arranged in the middle after being assembled; two plate bodies one 2-11 are respectively arranged on the left and right sides of plate body seven 2-17 and plate body six 2-16 (plate body one 2-11 is consistent in length with plate body six 2-16 and plate body seven 2-17, and the outer side surface of plate body one 2-11 is arc-shaped) to form a middle plate body; the plate body two 2-12 and plate body three 2-13 are assembled to form a first side plate body (the inner side is parallel and the outer side is arc-shaped), and the plate body four 2-14 and plate body five 2-15 are assembled to form a second side plate body (similar in structure to the first side plate body); the first side plate body and the second side plate body are assembled on the front and back sides of the middle plate body to form a heat spreader 2-1 as a whole.

[0053] After the plates are joined together to form the heat spreader 2-1, they are connected by rib plates; specifically, Figure 4As shown, the rib plate includes four L-shaped rib plates 1 2-18 and two U-shaped rib plates 2-19. The four L-shaped rib plates 1 2-18 are respectively arranged at the upper and lower corners of the heat spreader 2-1, and the two U-shaped rib plates 2-19 are arranged in the middle of the heat spreader 2-1. Corresponding bolt holes are opened on each rib plate and each plate body. Each rib plate is connected to each plate body through high-strength bolts, and each plate body is connected to at least two rib plates. The rib plates and high-strength bolts are made of carbon-carbon composite materials. Specifically, there are threaded holes on each plate body and corresponding through holes on the rib plates. The holes of the assembled plate bodies correspond to the holes of the rib plates one by one. Tighten and fix the high-strength bolts to connect and fix the plate bodies. The rib plate or heat spreader 2-1 is provided with symmetrical lifting ears to facilitate the lifting of the heat spreader 2-1. In this embodiment, there are 8 threaded holes on the four rib plates 2-18, and the four lifting ears 2-10 are fixed to the rib plate 2-18 by high-strength bolts made of carbon-carbon composite materials, which facilitates the lifting of the heat spreader 2-1 on the support 2-2.

[0054] Preferably, if Figures 5 to 8 As shown, the support member 2-2 includes a support block 2-21 and a connecting plate 2-22;

[0055] There are multiple support blocks 2-21, which are arranged in sequence and connected by connecting plates 2-22, and the middle part is enclosed to form a mounting hole;

[0056] The heat spreader 2-1 is arranged in the mounting hole, and the edge of the heat spreader 2-1 overlaps the inner edge of the support block 2-21.

[0057] In the present invention, Figures 9 to 12 As shown, the support block 2-21 includes a radially inward support portion 2-26, a radially outward extension portion 2-25, a vertically upward connection portion 2-23 and a vertically downward limit portion 2-24; the connection portions 2-23 of two adjacent support blocks 2-21 are connected by a connecting plate 2-22 (bolts connect the connecting plate 2-22 and the connection portions 2-23 of the two support blocks 2-21, and the bolts are carbon-carbon composite material bolts); the support portions 2-26 of each support block 2-21 enclose a mounting hole, and the edge of the heat spreader 2-1 overlaps the support portion 2-26 of the support block 2-21. The connecting plate 2-22 is an isostatically pressed graphite plate.

[0058] In this embodiment, the support member 2-2 is composed of 20 isostatically pressed graphite support blocks 2-21 spliced ​​end to end into a circular regular icosagonal shape, and is connected and fixed by connecting plates 2-22 and carbon-carbon composite material bolts.

[0059] like Fig.13 and 14A vacuum electric melting furnace for preparing quartz glass is shown, comprising a furnace body, a furnace cover 1-1, a heating device and the above-mentioned heat equalizing device, wherein the bottom and surrounding of the furnace body are surrounded, and the furnace cover 1-1 is arranged on the top of the furnace body; the heating device is installed at the lower part of the furnace cover 1-1; the heat equalizing device is located below the heating device, and the support member 2-2 of the heat equalizing device is overlapped on the top of the furnace body, and is surrounded with the furnace body to form a cavity, and the cavity is filled with crystal sand; the bottom of the furnace cover 1-1 is arranged on the extension part 2-25 of the support member 2-2.

[0060] In the present invention, Fig.13 As shown, the heat equalizing device is arranged below the heating device.

[0061] Preferably, the furnace body includes a bottom structure and a side structure; the bottom structure includes a steel bottom plate 3-5 and bottom bricks 3-4 laid on the steel bottom plate 3-5;

[0062] The side structure includes a steel cage 3-1 and inner insulation brick layers respectively arranged on the inner side of the steel cage 3-1, and zirconium oxide balls are filled between the steel cage 3-1 and the inner insulation brick layer 3-2; the bottom of the steel cage 3-1 is arranged on a steel bottom plate 3-5, and the bottom of the inner insulation brick layer 3-2 is arranged on a bottom brick 3-4; an outer insulation brick layer 3-3 is arranged on the outer side of the top of the steel cage 3-1 (the bottom of the outer insulation brick layer 3-3 is arranged on a horizontal member on the upper part of the steel cage 3-1, and zirconium oxide balls are also filled between the inner insulation brick layer 3-2 and the outer insulation brick layer 3-3);

[0063] The supporting portion 2-26 of the heat equalizing device support 2-2 is arranged on the top of the inner insulation brick layer 3-2, the extending portion 2-25 of the support 2-2 is overlapped on the top of the outer insulation brick layer 3-3, and the limiting portion 2-24 of the support 2-2 is inserted into the zirconia balls between the inner insulation brick layer 3-2 and the outer insulation brick layer 3-3 to ensure that the support 2-2 is firmly placed on the inner and outer insulation bricks.

[0064] In this embodiment, the steel cage 3-1, the inner insulation brick layer 3-2, the outer insulation brick layer 3-3, the bottom brick 3-4, and the steel bottom plate 3-5 constitute a furnace body that carries crystal sand (i.e., quartz sand). The steel cage 3-1 and the steel bottom plate 3-5 constitute the external frame of the furnace body; the bottom brick 3-4 is a zirconia brick, which is laid flat on the bottom of the frame; the inner insulation brick is stacked on the bottom brick 3-4, and the outer insulation brick is stacked on the steel cage 3-1, and the height of the inner and outer bricks is the same. The raw material crystal sand of quartz glass is filled inside the furnace body, and zirconia balls are filled between the inner insulation brick layer 3-2, the outer insulation brick layer 3-3 and the steel cage 3-1. The bottom structure and the side structure of the furnace body are existing structures and will not be repeated here.

[0065] In the present invention, the heating device and the furnace cover 1-1 are both components of the vacuum electric melting furnace, and the two are fixed to the upper furnace cover 1-1 of the vacuum electric melting furnace to form the working area of ​​the vacuum electric melting furnace. The heating device is a graphite heating element 1-2, which is made of isostatic graphite material and is powered on as a power source to provide the heat required for melting the crystal sand. The furnace cover 1-1 is made of graphite material, which can be graphite hard felt, and its function is to limit the heat within the required space to ensure that the heat does not leak too much to the metal furnace shell, thereby ensuring the safe production of the equipment.

[0066] A quartz glass preparation process based on the above device, the process comprising:

[0067] S1. Fill the furnace body of the device with quartz sand and then install the equalizing device: according to the diameter and height size surrounded by the insulation brick layer 3-2 in the steel cage 3-1, put enough raw material quartz sand into the furnace body, and then install the equalizing device (the side wall of the furnace body is provided with a lifting mechanism for driving the equalizing device to rise and fall. After the loading is completed, the equalizing device is hoisted from the side of the furnace body, and then the equalizing device is raised to the upper part of the furnace body under the action of the lifting mechanism);

[0068] S2. Vacuuming: Close the furnace cover 1-1 of the device and use a vacuum pump to evacuate the vacuum degree in the furnace to below 5Pa;

[0069] S3, heating: start heating, raise the temperature inside the furnace from room temperature to 1700°C, the heating rate is 180°C / h, then continue heating to 1900°C at a heating rate of 80°C / h, and keep warm for 60h, and keep the vacuum state during the heating and keeping period;

[0070] S4, cooling down to remove stress: after the insulation is completed, the temperature inside the furnace is lowered to 1300-1350°C and maintained for 20-30 hours for annealing to remove the internal stress of the quartz ingot;

[0071] S5. Cool down to room temperature: Continue to cool down until the temperature of the quartz ingot reaches room temperature, then open the device and take out the quartz ingot.

[0072] The present invention optimizes the process temperature and the heating rate by designing a soaking device, so that the temperature difference below the soaking plate 2-1 and the temperature without the soaking plate 2-1 is within 5‰, ensuring the original process temperature while making the temperature inside the furnace more uniform, and greatly reducing bubbles in the product.

[0073] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0074] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat equalization device, characterized in that: including a support member and a heat sink; The support member is an annular structure with a mounting hole in the middle; The heat spreader is an isostatically pressed graphite plate, which is arranged in the mounting hole of the support component, and the edge of the heat spreader is connected to the support component.

2. The heat equalizing device according to claim 1, characterized in that: The heat spreader includes a plurality of plates joined in the transverse and longitudinal directions. A step surface is provided at the joint of each plate to form a boss or a groove. The bosses and grooves of two adjacent plates cooperate with each other and are engaged and connected. Adjacent plates are connected by rib plates.

3. The heat equalizing device according to claim 1, characterized in that: The support member includes a support block and a connecting plate; There are multiple support blocks, which are arranged in sequence and connected by connecting plates, and the middle part is surrounded to form a mounting hole; The heat spreader is arranged in the mounting hole, and the edge of the heat spreader overlaps the inner edge of the support block.

4. The heat equalizing device according to claim 3, characterized in that: The support block includes a radially inward support portion, a radially outward extension portion, a vertically upward connection portion and a vertically downward limit portion; the connection portions of two adjacent support blocks are connected via a connecting plate; the support portions of each support block are enclosed to form a mounting hole, and the edge of the heat spreader is overlapped on the support portion of the support block; the connecting plate is an isostatically pressed graphite plate.

5. A vacuum electric melting furnace for preparing quartz glass, characterized in that: It comprises a furnace body, a furnace cover, a heating device and a heat equalizing device as claimed in claim 4, wherein the bottom and surrounding of the furnace body are surrounded, and the furnace cover is arranged on the top of the furnace body; the heating device is installed at the lower part of the furnace cover; the heat equalizing device is located below the heating device, and the support member of the heat equalizing device overlaps the top of the furnace body and encloses the furnace body to form a cavity, and the cavity is filled with crystal powder; the bottom of the furnace cover is arranged on the extension part of the support member.

6. The vacuum electric melting furnace according to claim 5, characterized in that: The furnace body includes a bottom structure and a side structure; the bottom structure includes a steel bottom plate and bottom bricks laid on the steel bottom plate; The side structure includes a steel cage and inner insulation bricks respectively arranged inside the steel cage, and zirconium oxide balls are filled between the steel cage and the inner insulation brick layer; the bottom of the steel cage is arranged on a steel bottom plate, and the bottom of the inner insulation brick is arranged on the bottom brick; an outer insulation brick layer is arranged on the top outer side of the steel beam; The support part of the heat equalizing device support is arranged on the top of the inner insulation brick layer, the extension part of the support is overlapped on the top of the outer insulation brick layer, and the limiting part of the support is inserted between the inner insulation brick layer and the outer insulation brick layer.

7. The vacuum electric melting furnace according to claim 1, characterized in that: Zirconia balls are filled between the inner insulation brick layer, the outer insulation brick layer and the steel cage.

8. A quartz glass preparation process based on the vacuum electric melting furnace as claimed in claim 5, characterized in that: The process includes: Fill the furnace body of the device with quartz sand, and then install a heat-saturating device; Vacuuming; Start the heating device to heat up, so that the temperature in the furnace rises to the set temperature, then keeps the temperature and maintains the vacuum state; Lower the temperature in the furnace to the set temperature and remove the stress inside the quartz ingot; The quartz ingot is then cooled to room temperature.

9. The quartz glass preparation process according to claim 8, characterized in that: The heating rate is 180°C / h.

10. The quartz glass preparation process according to claim 8, characterized in that: After the temperature in the furnace is lowered to 1300~1350℃, the internal stress of the quartz ingot is relieved.

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