Crucible smelting furnace structure with stable flow speed for smelting optical glass and control method

Abstract

The invention discloses a crucible smelting furnace structure with stable flow speed for smelting optical glass and a control method. Belongs to the technical field of glass production equipment. The invention mainly solves the problem that the molding size of optical glass is influenced by the gradual reduction of the flow rate of molten glass at a pipe orifice due to the gradual reduction of the liquid level of the existing single crucible. The device is mainly characterized by comprising a melting chamber, a transition material pipe and a transition chamber, wherein the transition material pipe is connected between the bottom of the melting chamber and the top of the transition chamber; the side part of the transition chamber is provided with an overflow port, and the bottom is provided with a leakage pipe. Wherein a plurality of groups of melting chambers are arranged; the leakage pipe has the characteristics of effectively stabilizing the liquid pressure at the outlet of the leakage pipe, stabilizing the flow velocity of the glass liquid in the leakage pipe and ensuring the consistency of glass forming specifications and dimensions, and can be widely applied to glass products formed by leakage, especially high-precision optical glass devices with strict requirements on specifications and dimensions.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass production equipment and relates to an optical glass blank production equipment, in particular to a crucible furnace structure with the function of stabilizing the flow of molten glass, which is suitable for the production of optical glass blanks such as leather material tubes, precision molded preforms, one-time molded parts, plates, and rods. Background Art

[0002] In the production of optical glass blanks, it is hoped that the optical glass blanks will be produced with the minimum redundancy according to the size of the final optical component, so as to reduce the waste of glass caused by cold processing. In particular, for optical glass blanks such as optical glass skin material tubes and precision molded preforms, which have higher use requirements, high precision is required due to the difficulty of cold processing. Therefore, there are higher requirements for the dimensional accuracy of one-time molding. The current production of optical glass blanks is mainly based on leakage molding with platinum material tubes as channels. Its melting structure is mainly in the form of continuous melting furnace and single crucible. The advantage of the continuous melting furnace is that the liquid level is stable. When the process temperature parameters change, its flow rate is stable, and the size of the formed optical glass blank can be controlled more stably. The disadvantage is that the amount of platinum used is large, resulting in high platinum loss, and the continuous feeding method is not suitable for the production of optical glass blanks with small output. Relatively speaking, the structure of a single crucible is relatively simple, and the amount of platinum used is relatively small. It is suitable for the production of optical glass blanks with small demand. The disadvantage is that as the glass liquid is lost, the liquid level will gradually drop, and the pressure of the glass liquid on the leakage port will gradually decrease, causing the flow rate at the tube port to gradually decrease, affecting the molding size of the optical glass. In actual production, this change will be compensated by gradually increasing the temperature of the leakage tube, but this compensation process is dynamic and has great instability, resulting in fluctuations in the flow rate of the glass liquid during the production process, which ultimately affects the stability of the molding size. Summary of the invention

[0003] The present invention proposes a crucible furnace structure and control method for optical glass melting with a stable flow rate, the purpose of which is to structurally compensate for the reduction in the glass liquid pressure of a leakage pipe, so as to maintain the stability of the flow rate of the glass liquid in the leakage pipe during the forming process, and achieve the purpose of accurately controlling the glass forming size.

[0004] From the perspective of mechanics, the pressure on the leaking pipe is P, which is the pressure of the glass liquid on the leaking pipe. 液 =ρhg, the glass surface is subjected to atmospheric pressure P 气 =P0, then the total pressure is P=ρhg+ P0, where P o It is equal to the atmospheric pressure. ρ and g are the density and gravitational acceleration of the glass liquid respectively. They are constants at fixed positions. Therefore, the pressure will only gradually decrease as the liquid level decreases.

[0005] The technical solution of the crucible furnace structure of the present invention is: a crucible furnace structure for optical glass melting with a stable flow rate, including a melting chamber, characterized in that it also includes a transition material pipe and a transition chamber; wherein the transition material pipe is connected between the bottom of the melting chamber and the top of the transition chamber; an overflow port is provided on the side of the transition chamber, and a leakage pipe is provided on the bottom.

[0006] The technical solution of the crucible furnace structure of the present invention also includes a receiving crucible; the receiving crucible cooperates with the overflow port to receive the overflowing glass liquid; the transition material pipe is provided with a heating electrode, and the part exposed to the melting chamber and the transition chamber is wrapped with insulation cotton.

[0007] In the technical solution of the crucible furnace structure of the present invention, the melting chamber is composed of a melting crucible and a melting crucible furnace body, and the melting crucible is provided with a stirrer; the transition chamber is a transition crucible, and a laser liquid level meter is provided on the top; the transition material pipe is composed of an F1 transition material pipe, an F2 transition material pipe and an F3 transition material pipe, the F1 transition material pipe is connected to the melting crucible, the F3 transition material pipe is connected to the transition crucible, and the F2 transition material pipe is connected between the F1 transition material pipe and the F3 transition material pipe; the effective volume of the transition chamber is 3% to 60% of the melting chamber.

[0008] In the technical solution of the crucible furnace structure of the present invention, the F2 transition pipe is replaceably connected to the F1 transition pipe and the F3 transition pipe; the effective volume of the transition chamber is 15% to 30% of the melting chamber.

[0009] In the technical solution of the crucible furnace structure of the present invention, the lower end of the transition material pipe is lower than the lower end of the overflow port.

[0010] In the technical solution of the crucible furnace structure of the present invention, the lower end of the transition material pipe is 10-30 mm lower than the lower end of the overflow port.

[0011] In the technical solution of the crucible furnace structure of the present invention, the area from the lower end of the transition material pipe to the upper horizontal position of the overflow port is a semi-open structure.

[0012] The upper end of the semi-open structure in the technical solution of the crucible furnace structure of the present invention is 10-30 mm away from the glass liquid surface.

[0013] In the technical solution of the crucible furnace structure of the present invention, there are one or more melting chambers.

[0014] The technical solution of the control method of the present invention is: a control method for a crucible furnace for optical glass melting with a stable flow rate, characterized by comprising the following steps: (1) The diameter of the transition pipe is selected according to the diameter of the leakage pipe, so that the flow rate of the glass liquid flowing into the transition chamber through the transition pipe is greater than the flow rate of the glass liquid flowing out of the leakage pipe, or the temperature of the glass liquid in the transition pipe is adjusted so that the flow rate of the glass liquid flowing into the transition chamber through the transition pipe is greater than the flow rate of the glass liquid flowing out of the leakage pipe; an overflow port is set at a set height in the transition chamber to keep the glass liquid level in the transition chamber stable, so as to maintain the stability of the glass liquid flow rate of the leakage pipe: (2) When there are multiple melting chambers, when the glass liquid in one melting chamber is close to running out, the next melting chamber that has completed melting, clarification and homogenization is switched to start production in sequence, and the purpose of continuous production is achieved by alternating back and forth in this way.

[0015] The beneficial effect of the present invention is that by adding a transition pot and an overflow port to maintain the liquid level of the transition crucible above the forming leakage pipe stable, the liquid pressure at the outlet of the leakage pipe can be effectively stabilized, thereby stabilizing the flow rate of the glass liquid in the leakage pipe. In addition, the consistency of the specifications and dimensions of the glass molding can be ensured. By adding multiple groups of single crucible structures, the continuous production of small-volume precision optical glass is achieved, providing a solution for the stable production of small-size precision optical glass blanks. The present invention can be widely used in glass products formed by leakage, especially for high-precision optical glass devices with strict specifications and dimensions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of the furnace structure for stabilizing the flow rate of the optical glass single crucible leakage tube in the present invention.

[0017] Figure 2 It is a cross-sectional view of the structure of the transition crucible in the present invention.

[0018] Figure 3 It is a front view of the F3 transition material pipe in the present invention.

[0019] Figure 4 It is a three-dimensional diagram of the F3 transition pipe in the present invention.

[0020] Markings in the figure are: 100-melting chamber; 110-melting crucible; 120-melting crucible furnace body; 130-stirrer; 200-transition material pipe; 210-F1 transition material pipe; 220-F2 transition material pipe; 230-F3 transition material pipe; 300-transition chamber; 310-transition crucible; 320-leakage pipe; 330-receiving crucible; 340-overflow port. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present invention, the present invention is further described below in conjunction with the accompanying drawings.

[0022] like Figures 1 to 4As shown, the crucible furnace structure for melting optical glass with stable flow rate disclosed in the present invention is composed of three parts: a melting chamber 100, a transition material pipe 200 and a transition chamber 300.

[0023] There are two melting chambers 100 with the same structure, which are used for the melting, clarification and homogenization steps of the glass batch material. The same as the prior art, the corresponding process system is formulated according to the glass components of different grades. The melting chamber 100 is composed of a melting crucible 110 and a melting crucible furnace body 120. A stirrer 130 is arranged above the melting crucible 110. During the melting process, the stirrer 130 stirs downward to homogenize the glass liquid.

[0024] The transition pipe 200 is connected between the bottom of the melting chamber 100 and the top of the transition chamber 300. There are two sets of transition pipes 200, each consisting of an F1 transition pipe 210, an F2 transition pipe 220 and an F3 transition pipe 230. The F1 transition pipe 210 is connected to the corresponding melting crucible 110, the F3 transition pipe 230 is connected to the transition crucible 310, the F2 transition pipe 220 is connected between the corresponding F1 transition pipe 210 and the corresponding F3 transition pipe 230, and the F2 transition pipe 220 is arranged in a horizontal direction. The F2 transition pipe 220 is replaceably connected to the F1 transition pipe 210 and the F3 transition pipe 230. The transition pipe 200 connects two separate furnace chambers, and a portion is exposed outside the furnace chamber and wrapped with heat insulation cotton. The upper part of the horizontal position from the lower end of the F3 transition tube 230 to the upper end of the overflow port 340 is a semi-open structure. The upper end of the semi-open treatment is above the glass liquid level, preferably 10-30mm higher than the glass liquid level. The opening ratio is preferably 30%~60% of the original transition tube. The glass liquid flows down along the open half-tube wall. The upper end of the semi-open is above the glass liquid level and contacts the air, which strongly separates the glass liquid of the melting crucible and the transition crucible, ensuring that the liquid pressure of the transition crucible is only affected by the height of the transition crucible liquid level. The lower end of the F3 transition tube 230 is lower than the lower end of the overflow port 340, preferably 10-30mm lower than the lower end of the overflow port 340. The glass liquid flows into the transition crucible from the semi-open tube wall, reducing the impact on the surface of the glass liquid and avoiding liquid level fluctuations. The F1 transition tube 210, the F2 transition tube 220 and the F3 transition tube 230 are provided with heating electrodes. The length and diameter of the F1 transition pipe 210 and the F3 transition pipe 230 are fixed, and the F2 transition pipe 220 can be replaced, and its diameter can be individually designed according to different glass grades and the flow rate required for product molding. The transition pipe 200 transports the smelted glass liquid to the transition crucible 310, wherein the F2 transition pipe 220 is arranged outside the melting chamber 100 and the transition chamber 300. In the process of changing the grade of the F2 transition pipe 220, the diameter of the pipe that meets the requirements is replaced based on the actual required discharge amount and the viscosity temperature curve of the corresponding grade. When in normal production, the F1 transition pipe 210, the F2 transition pipe 220 and the F3 transition pipe 230 are electrically heated, and the temperature is controlled by the size of the current to stabilize the flow rate of the glass liquid of the F1 transition pipe 210, the F2 transition pipe 220 and the F3 transition pipe 230.

[0025] The transition chamber 300 is composed of a transition crucible 310 and a receiving crucible 330. An overflow port 340 is provided on the side of the transition crucible 310, and a leakage pipe 320 is provided at the bottom. The receiving crucible 330 cooperates with the overflow port 340 to receive the overflowed glass liquid, which can be returned to the furnace for remelting. The effective volume of the transition chamber 300 is 3% to 60% of the melting chamber 100, preferably 15% to 30% of the melting chamber 100. The function of the transition chamber 300 is mainly to stabilize the liquid level. The glass liquid flowing from the melting crucible 110 gradually fills the transition crucible 310. When the liquid level gradually approaches the height of the overflow port 340, the leakage pipe 320 starts to discharge. During normal production, the flow rate of the transition material pipe 200 is controlled to be slightly greater than the flow rate of the leakage pipe 320, and the excess glass liquid flows out through the overflow port to maintain a stable liquid level. The melting pot 110 and the transition pot 310 are in different furnace cavities. A laser level meter is arranged above the transition crucible 310 to monitor the liquid level. By adjusting the current and temperature of the transition material pipe 200 , the flow rate of the transition material pipe 200 is controlled to be always greater than the amount of molding material in the transition crucible 310 , thereby maintaining the stability of the liquid level.

[0026] A method for controlling a crucible furnace for optical glass melting with a stable flow rate comprises the following steps: (1) The diameter of the transition material pipe 200 is selected according to the diameter of the leakage pipe 320, so that the flow rate of the glass liquid flowing into the transition chamber 300 through the transition material pipe 200 is greater than the flow rate of the glass liquid flowing out of the leakage pipe 320, or the temperature of the glass liquid in the transition material pipe 200 is adjusted so that the flow rate of the glass liquid flowing into the transition chamber 300 through the transition material pipe 200 is greater than the flow rate of the glass liquid flowing out of the leakage pipe 320; the overflow port 340 is set at a set height in the transition chamber 300, so that the height of the glass liquid level in the transition chamber 300 remains stable, so as to maintain the stability of the glass liquid flow rate of the leakage pipe 320; (2) When there are multiple melting chambers 100, when the glass liquid in one melting chamber 100 is close to running out, the next melting chamber 100 that has completed melting, clarification and homogenization is switched to start production in sequence, and the purpose of continuous production is achieved by alternating back and forth in this way.

[0027] When the glass liquid in the first group of melting crucibles 110 is used for molding, it can be melted in the second group of melting crucibles 110; when the glass liquid in the first group of melting crucibles 110 is close to running out, the corresponding transition pipes 200 of the first group are powered off, and the corresponding transition pipes 200 of the second group of melting crucibles 110 are powered on to flow the glass liquid into the transition crucible 310 for molding.

[0028] To avoid unstable liquid levels during the switching of multiple crucibles, the next group of melting crucibles 110 can be discharged in advance when the previous group of melting crucibles 110 is close to flowing out, and the excess glass liquid will overflow into the receiving crucible 330 .

[0029] According to the structure and control method of the present invention, a single-crucible furnace structure for optical glass is designed, and a corresponding control method is used to produce a drip (precision molded preform). Three products of different specifications are produced, and 500 groups of sampling data (three groups, ABC) are taken for each sample and compared with the sampling data of a drip produced by a common single-crucible leakage tube structure (group D). The weight data are shown in Table 1 below, which compares the weight stability of the preform produced by the furnace structure and control method designed by the present invention and the preform produced by the common production method.

[0030] According to the data obtained in Table 1, the weight stability of the three groups of precision molded preforms of different products obtained by the present invention is good, and the range and standard deviation of the weight are better than those of the precision molded preforms produced by ordinary single crucibles. It is proved that the present invention can stabilize the flow rate of the single crucible leakage tube, thereby stabilizing the molding control of the precision optical glass blank.

Claims

1. A crucible furnace structure for melting optical glass with a stable flow rate, comprising a melting chamber (100), characterized in that: It also includes a transition material pipe (200) and a transition chamber (300); wherein the transition material pipe (200) is connected between the bottom of the melting chamber (100) and the top of the transition chamber (300); an overflow port (340) is provided on the side of the transition chamber (300), and a leakage pipe (320) is provided on the bottom.

2. The crucible furnace structure for melting optical glass with a stable flow rate according to claim 1, characterized in that: It also includes a receiving crucible (330); the receiving crucible (330) cooperates with the overflow port (340) to receive overflowing glass liquid; the transition material pipe (200) is provided with a heating electrode, and the portion exposed to the melting chamber (100) and the transition chamber (300) is wrapped with heat-insulating cotton.

3. A crucible furnace structure for melting optical glass with a stable flow rate according to claim 1 or 2, characterized in that: The melting chamber (100) is composed of a melting crucible (110) and a melting crucible furnace body (120), wherein the melting crucible (110) is provided with a stirrer (130); the transition chamber (300) includes a transition crucible (310), and a laser level meter is provided on the top; the transition material pipe (200) is composed of an F1 transition material pipe (210), an F2 transition material pipe (220), and an F3 transition material pipe (230), wherein the F1 transition material pipe (210) is connected to the melting crucible (110), the F3 transition material pipe (230) is connected to the transition crucible (310), and the F2 transition material pipe (220) is connected between the F1 transition material pipe (210) and the F3 transition material pipe (230); and the effective volume of the transition chamber (300) is 3% to 60% of the melting chamber (100).

4. The crucible furnace structure for melting optical glass with a stable flow rate according to claim 3, characterized in that: The F2 transition material pipe (220) is replaceably connected to the F1 transition material pipe (210) and the F3 transition material pipe (230); the effective volume of the transition chamber (300) is 15% to 30% of the melting chamber (100).

5. A crucible furnace structure for melting optical glass with a stable flow rate according to any one of claims 1 to 2 and 4, characterized in that: The lower end of the transition pipe (200) is lower than the lower end of the overflow port (340).

6. The crucible furnace structure for melting optical glass with a stable flow rate according to claim 5, characterized in that: The lower end of the transition pipe (200) is 10-30 mm lower than the lower end of the overflow port (340).

7. A crucible furnace structure for melting optical glass with a stable flow rate according to any one of claims 1 to 2, 4 and 6, characterized in that: The area above the horizontal position from the lower end of the transition pipe (200) to the upper end of the overflow port (340) is a semi-open structure.

8. The crucible furnace structure for melting optical glass with a stable flow rate according to claim 7, characterized in that: The upper end of the semi-open structure is 10-30 mm away from the glass liquid surface.

9. A crucible furnace structure for melting optical glass with a stable flow rate according to any one of claims 1-2, 4, 6, and 8, characterized in that: The number of the melting chamber (100) is one or more.

10. A method for controlling a crucible furnace for melting optical glass with a stable flow rate according to any one of claims 1 to 9, characterized in that The following steps are involved: (1) The diameter of the transition material pipe (200) is selected according to the diameter of the leakage pipe (320), so that the flow rate of the glass liquid flowing into the transition chamber (300) through the transition material pipe (200) is greater than the flow rate of the glass liquid flowing out of the leakage pipe (320), or the temperature of the glass liquid in the transition material pipe (200) is adjusted so that the flow rate of the glass liquid flowing into the transition chamber (300) through the transition material pipe (200) is greater than the flow rate of the glass liquid flowing out of the leakage pipe (320); and an overflow port (340) is provided at a set height in the transition chamber (300), so that the height of the glass liquid level in the transition chamber (300) remains stable, so as to maintain the stability of the glass liquid flow rate of the leakage pipe (320); (2) When there are multiple melting chambers (100), when the glass liquid in one of the melting chambers (100) is close to running out, the next melting chamber (100) that has completed melting, clarification and homogenization is switched to start production, and the purpose of continuous production is achieved by alternating back and forth in this way.

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