CN113137858B - Cold crucible base and discharging method thereof - Google Patents

Abstract

The invention relates to a cold crucible base and a discharging method, wherein the cold crucible base structure comprises a discharging pipe, a central discharging hole, a water-cooling metal split structure and a medium-frequency induction heating system.

Description

Cold Crucible Base and Its Feeding Method

technical field

The invention relates to the field of vitrification of nuclear waste, in particular to a base of a cold crucible and a discharging method thereof.

Background technique

The cold crucible device is the core unit of the nuclear waste vitrification equipment. In this device, it is necessary to complete the processes of feeding, melting, stirring, bubbling and discharging, and configure a cooling water system, a high-frequency induction heating system, an exhaust gas treatment system and an automatic control system.

The wall (1) of the cold crucible is usually a segmented structure, and cooling water passes through the segmented metal tubes or arc-shaped metal plates. Because the temperature of the crucible wall generally does not exceed 200°C, the glass in contact with the cold wall will solidify and form a "cold shell". The thickness of the cold shell is usually about 1cm. The bottom of the crucible is also a water-cooled metal plate, and the glass is completely contained in the solid glass "cold shell", so it is called a cold crucible induction heating furnace. The crucible is surrounded by a high-frequency induction coil (2). The coil provides a high-frequency magnetic field to generate an induced current in the molten glass, and heats the melt in the crucible through the Joule heating effect to realize the induction melting process of the glass. The whole crucible body and the bottom of the crucible are all fixed on the refractory base (4). Due to the existence of the cold shell, the cold crucible is not easily corroded and has a long service life. After the glass in the cold crucible reaches a stable state, use the freeze-thaw valve or gate valve to discharge the high-temperature glass into the glass storage tank, and complete the discharge process after reaching the predetermined discharge weight. After that, periodic operations such as feeding, melting and discharging are carried out.

The French Atomic Energy Commission discloses a gate valve discharge structure (CN00802430.8). This structure has good compatibility with refractory glass, but the discharge flow rate of the glass is not easy to control, and it is easy to cause overflow of the glass storage tank and cause accidents. . At the same time, the structure of the gate valve is complicated, it is not easy to replace, and it is difficult to carry out long-distance maintenance in a high-radiation environment.

Idaho Falls in the United States discloses a cold crucible freeze-thaw valve discharge structure (US2005/0111518A1). Crystals lead to difficulty in repeated feeding or even material blockage. At the same time, poor temperature control will erode the material of the freeze-thaw valve, especially when operating the vitrification of refractory high-level radioactive waste, the temperature needs to be raised, which in turn affects the service life.

Korea Hydroatomic Power Co., Ltd. discloses a cold crucible freeze-thaw valve base discharge structure (CN103180682B). The base adopts a downwardly inclined water-cooled bottom plate eccentric to one side, combined with leakage from the eccentric freeze-thaw valve, it can improve high-frequency induction heating. Efficiency, so that refractory materials can also be discharged. However, its base structure design is relatively complicated, and the leakage pipe adopts a water-cooled grid structure, so it is difficult to control the discharge temperature and discharge flow rate.

The China Institute of Atomic Energy discloses a high-temperature melt freeze-thaw valve unloading device for cold crucibles (CN201610478762.1). It is not easy to replace it remotely when the leakage pipe is deformed or damaged.

At the same time, due to the influence of high-frequency and medium-frequency electromagnetic induction, the commonly used thermocouples for temperature measurement have poor anti-interference ability, which is not conducive to the remote operation of discharging materials. Therefore, the temperature control of the discharge is one of the bottlenecks affecting the remote control of the cold crucible vitrification discharge operation, which is not involved in the above patents.

In addition, the position selection of the discharge hole is also a key parameter for the design of the bottom of the cold crucible. Most cold crucibles usually adopt an eccentric structure design, combined with a water-cooled stirring mechanical structure at the top, which is conducive to releasing the glass at a higher temperature (skin depth). However, the design of the mechanical structure of the water-cooled mechanical stirring is complicated, which increases the difficulty of assembling the crucible top structure. Not only that, the metal material of the stirring paddle is easily corroded by the gas phase and liquid phase of the high temperature glass, and the reliability is poor.

Contents of the invention

In order to overcome the deficiencies in the design of the existing cold crucible bottom, the present invention provides a cold crucible base and a material discharging method. The cold crucible base can realize the remote control of the freeze-thaw valve discharge in the center of the cold crucible. The cold crucible base has a simple structure, easy It has the advantages of long-distance maintenance and replacement, good reliability and convenient discharge of precious metals.

Technical solution of the present invention is as follows:

A cold crucible base, characterized in that: the water-cooled crucible base includes a material leakage pipe, a central material leakage port, a water-cooled metal split structure and an intermediate frequency induction heating system,

The central leakage opening is located at the center of the water-cooled crucible base, and includes an inverted cone-shaped leakage opening and multiple sets of heat conduction plates arranged symmetrically from the inside to the outside relative to the inverted cone-shaped leakage opening. and a thermal insulation tank, the lower end of the central leaking port is connected to the leaking tube through a leaking tube fixing flange, a temperature measuring hole is arranged outside the upper end of the leaking tube, and the The lower end of the leakage pipe is provided with a water-cooled gate valve, and the water-cooled metal split structure is formed around the central leakage opening, and the water-cooled metal split structure includes a plurality of water-cooled metal boxes, bubbling ports and The base is slit, and the base is slit between the two water-cooled metal boxes. The bubbling openings are symmetrically arranged on the upper surface of each water-cooling metal box at half the radius of the crucible base, and the number of the bubbling openings is Half of the number of the water-cooled metal box, the lower surface of the water-cooled metal box is provided with a water inlet pipe and a water outlet pipe, and an air inlet pipe is also provided on the lower surface of the water-cooled metal box corresponding to the bubbling port , the air inlet pipe passes through the inner cavity of the water-cooled metal box and is connected to the bubbling port, the bubbling port is higher than the upper surface of the water-cooled metal box, and the gap between the base and the crucible body Refractory mud is filled in the connection joints, base openings and heat insulation grooves;

The intermediate frequency induction heating system includes a temperature measuring thermocouple, an isolation transmitter, a temperature controller, an intermediate frequency induction power supply and an intermediate frequency induction coil. The temperature measuring thermocouple is arranged in the temperature measuring hole, and the The intermediate frequency induction coil is provided outside the leakage tube, and the intermediate frequency induction coil is powered by the intermediate frequency induction power supply, and the temperature measuring thermocouple is connected to the temperature controller through the isolation transmitter.

The temperature-measuring thermocouple is a high-temperature-resistant S-type (platinum-rhodium 10%-platinum) thermocouple, which is placed in a metal sleeve after insulation treatment to prevent high-frequency and intermediate-frequency electromagnetic interference. Metal casing, its material is usually copper or stainless steel; The temperature measuring thermocouple, its temperature measuring point is as close as possible to the fixed flange of the leaking pipe, and is located at 5mm near the upper part of the intermediate frequency induction coil, and the depth extends into the The leaking pipe mentioned above is 2-4 mm away from the tapered leaking port.

The material of the leakage pipe is 690 alloy, 310S, 304 or 316, and it should be degaussed after processing. It is advisable to be between ～150°C; and the upper limit temperature of the leakage channel center of the leakage pipe is not higher than 1150°C, and the long-term working temperature should not be higher than 1100°C. 60 to 150°, preferably 90 to 120°.

The radial width of the heat conduction plate is 2-8mm, preferably 2-4mm; the arc of the circumference with the relative bubbling mouth as the center is 20-30°; the height of the heat conduction plate is 1-3cm , the best is 1 ~ 2cm.

The radial width of the heat-insulation groove is 5-15mm, preferably 5-10mm; the circumference width is 20-40° with the relative bubbling mouth as the center of the circle; 2/5～1, the best is 3/5～4/5.

The material of the water-cooled metal box is stainless steel 304 or 316, and it should be degaussed after processing, and the cooling water is introduced into the cavity of the metal box from the water inlet pipe and the water outlet pipe; the number of the water-cooled metal box is set to 4～ 12 splits, preferably 6 or 8 splits.

The bubbling opening protrudes from the upper surface of the water-cooled metal box by 1-3 cm, preferably 1-2 cm.

The width of the slit of the base is 4-15 mm, preferably 4-8 mm.

The distance between the heat insulation groove and the heat conducting plate is 1-5mm.

The refractory mud is aluminosilicate, and the content of alumina in the aluminosilicate is not less than 70%, so as to ensure the refractoriness and sealing performance of the base.

The temperature controller uses a PLC combined with a touch screen to realize parameter setting, PID control, parameter display and data recording functions, and can realize double PID switching of temperature VS power and weight VS power; the working frequency of the intermediate frequency induction power supply is 10-20kHz, working in water-cooled or air-cooled mode; the length of the intermediate frequency induction coil is preferably 1-3cm exposed from the bottom of the leakage pipe; the inner diameter of the intermediate frequency induction coil is the diameter of the leakage pipe Between 1.1 and 1.3 of the outer diameter.

The method for discharging the high-temperature glass of the above-mentioned cold crucible comprises the following steps:

1) After the glass in the cold crucible is ignited, expanded and melted, continue to add new glass beads or glass clinker to the cold crucible in batches until the rated load state is reached, and the melt temperature in the glass reaches 1150°C;

2) Set the bubbling flow rate of the bubbling port (16) to 10-80L/h, preferably 10-40L/h;

3) Adjust the cooling flow rate of the water-cooled base so that the temperature difference between the inlet and outlet water of the base is controlled at 20-40°C and does not exceed the critical temperature and pressure of the cooling water pipe;

4) Turn on the medium frequency induction heating power supply and temperature controller;

5) Set the heating program on the touch screen of the temperature controller: the heating rate is 20-50°C/min, when the temperature reaches 400°C, keep the temperature constant for 5-10min, then change the heating rate to 30-60°C/min, When it reaches 700°C, keep the temperature constant for 3-8 minutes, then change the heating rate to 30-50°C/min, and when the temperature reaches _TL (glass liquidus temperature)+30-50°C, keep the temperature constant;

5) On the touch screen of the temperature controller, set the weight control program according to the discharge flow needs;

6) The temperature controller compares the set segmental temperature curve (SV) with the measured temperature signal (PV) of the thermocouple through the isolation transmitter, performs PID analysis, and outputs the control signal to the intermediate frequency power supply, and the intermediate frequency power supply passes through The intermediate frequency induction coil transfers the energy to the leakage tube;

7) Open the water-cooled gate valve (9) to discharge the material to the glass storage tank. When the material is discharged and the weight signal is stable, immediately switch to weight VS power PID control, that is, the controller is based on the set segmented weight curve ( SV) is compared with the measured weight signal (PV) of the leaked glass, PID analysis is carried out, and the control signal is output to the intermediate frequency power supply, and the intermediate frequency power supply transmits the energy to the leaking material pipe through the intermediate frequency induction coil, and then controls the channel of the leaking material pipe (22 ) The discharge flow rate of high temperature glass;

8) When the weight of the glass storage tank is about to reach the target weight, first turn off the heating of the intermediate frequency power supply through PID control, and when the weight of the glass storage tank reaches the target weight, close the water-cooled gate valve (9) to complete a round of discharging material flow;

9) Continue to feed materials into the cold crucible, and after the complete melting reaches the rated glass load, proceed to the next round of discharging process.

Compared with prior art, the beneficial effect of the present invention is:

1) The gap between the crucible base of the device is filled with aluminosilicate refractory mud, which can increase the sealing performance and electrical insulation performance of the device;

2) The center of the crucible base adopts a symmetrical slot structure to avoid the difficulty of material leakage in the center caused by the overcooling of the water-cooled split valve;

3) In the center of the base of the device, the same number of heat conduction plates as the number of heat insulation tanks is added, combined with the symmetrically designed bubbling mouth, the heat of the molten glass above the cold shell can also be conducted without using the top water-cooled mechanical stirring device To the leakage port, it is not only conducive to the leakage of high-temperature glass from the leakage port, but also conducive to the discharge of precious metals;

4) For the medium frequency induction heating system of this device, a platinum-rhodium thermocouple with a metal sleeve is added to the upper end of the leakage pipe, and the temperature controller is input through photoelectric isolation to further control the output of the medium frequency power supply, combined with the weight signal of the glass storage tank , can realize double PID control, can effectively avoid the problem of ultra-high temperature operation and short life of the leakage pipe;

5) The leakage tube of this device is directly fixed on the lower part of the center of the base with a tray, and does not extend into the base, which reduces the difficulty of assembly and disassembly of the cold crucible, and facilitates long-distance maintenance and replacement of the manipulator during radioactive operation.

Description of drawings

Fig. 1 is a schematic structural view of the cold crucible bottom (position below the high-frequency coil) of the present invention;

Fig. 2 is a top view of the water-cooled cold crucible base structure of the present invention;

Fig. 3 is a schematic structural view of a leakage pipe of the present invention;

Fig. 4 is a structural schematic diagram of the leakage pipe fixing flange of the present disclosure;

Fig. 5 is a schematic structural diagram of a water-cooled gate valve of the present disclosure;

Fig. 6 is a schematic diagram of the intermediate frequency induction control system of the present disclosure.

In the figure: 1—water-cooled crucible wall; 2—high-frequency induction coil; 3—water-cooled metal box; 4—refractory base; 5, 17&20—refractory mud joint filling; 6—temperature measuring thermocouple; —Leakage pipe; 9—Water-cooled gate valve; 10&12—Water inlet and outlet pipes; 11—Intake pipe; 13—Fixing flange of leakage pipe; 14—Central leakage port; 15—Water-cooled crucible base split structure; 16—Bubble port ;18—heat conduction plate; 19—insulation groove; 21—temperature measuring hole; 22—leakage channel; 23—fixed flange positioning bolt hole; 24—perforation of leakage pipe; 25—water cooling gate valve inlet and outlet pipe; 26—water cooling Gate valve water cooling chamber.

Detailed ways

The present invention will be further described below in conjunction with the embodiments and accompanying drawings, but the protection scope of the present invention should not be limited thereby.

First please refer to Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, as can be seen from the figures, the cold crucible of the present invention includes a water-cooled crucible wall 1, a high-frequency induction coil 2 and a water-cooled crucible base, and the high-frequency induction coil 2. It is arranged around the wall 1 of the water-cooled crucible, and the wall 1 of the water-cooled crucible and the base of the water-cooled crucible are placed on the refractory base 4. Leakage port 14, water-cooled metal split structure 15 and medium frequency induction heating system,

The central leakage opening 14 is located at the center of the water-cooled crucible base, and includes an inverted cone-shaped leakage opening and a plurality of groups symmetrically distributed from the inside to the outside relative to the inverted cone-shaped leakage opening 14. The heat conducting plate 18 and the heat insulating groove 19 are fixedly connected to the leaking pipe 8 at the lower end of the central leaking port 14 through the leaking pipe fixing flange 13, and on the outside of the upper end of the leaking pipe 8 A temperature measuring hole 21 is provided, and a water-cooled gate valve 9 is provided at the lower end of the leakage pipe 8. Around the central leakage opening 14 is the water-cooled metal split structure 15, and the water-cooled metal The split structure 15 includes a plurality of water-cooled metal boxes 3, bubbling openings 16 and base slits 17, between the two water-cooled metal boxes 3 is a base slit 17, and the upper surface of each water-cooled metal box 3 is within the crucible base radius Said bubbling opening 16 is arranged symmetrically at half of the said bubbling opening 16, and the quantity of said bubbling opening 16 is half of the quantity of said water-cooled metal box 3, and the lower surface of said water-cooled metal box 3 is provided with a water inlet pipe 10 and Outlet pipe 12, on the lower surface of said water-cooled metal box 3, corresponding to said bubbling port 16, an air inlet pipe 11 is also provided, and said air inlet pipe 11 passes through the inner cavity and the drum of said water-cooled metal box. The bubble mouth (16) is connected, and the bubble mouth 16 is higher than the upper surface of the water-cooled metal box 3, and the connection seam 5 between the base and the crucible body, the base slit 17 and the heat insulation groove 19 are filled with refractory mortar;

The intermediate frequency induction heating system includes a temperature measuring thermocouple 6, an isolation transmitter, a temperature controller, an intermediate frequency induction power supply and an intermediate frequency induction coil 7, and the temperature measuring thermocouple 6 is arranged in the temperature measuring hole 21 , the intermediate frequency induction coil 7 is set outside the leakage pipe 8, the intermediate frequency induction coil 7 is powered by the intermediate frequency induction power supply, and the temperature measuring thermocouple 6 is connected with the isolation transmitter through the The temperature controller is connected.

The temperature-measuring thermocouple 6 is a high-temperature-resistant S-type (platinum-rhodium 10%-platinum) thermocouple, which is placed in a metal sleeve after insulation treatment to prevent high-frequency and intermediate-frequency electromagnetic interference. Even metal casing, its material is usually copper or stainless steel; The temperature measuring point 21 of described temperature measuring thermocouple is as close as possible to described leaking material pipe fixing flange 13, and is positioned at the upper vicinity 5mm of described intermediate frequency induction coil 7 The depth extends into the leakage pipe, and is 2-4 mm away from the tapered leakage opening.

The material of the leaking pipe 8 is 690 alloy, 310S, 304 or 316, and it should be demagnetized after processing. The length of the leaking pipe 8 depends on the temperature at the thermocouple and the temperature gradient at the center of the intermediate frequency induction coil It is advisable between 100-150°C; and the upper limit temperature of the center of the leakage channel 22 of the leakage pipe 8 is not higher than 1150°C, and the long-term working temperature should not be higher than 1100°C. Trumpet-shaped, with a taper of 60-150°, preferably 90-120°.

The radial width of the heat conducting plate 18 is 2 to 8 mm, preferably 2 to 4 mm; the circumferential width is 20 to 30° with the relative bubbling mouth as the center of the circle; the height of the heat conducting plate 18 is 1 ~3cm, preferably 1~2cm.

The radial width of the heat-insulation groove 19 is 5-15mm, preferably 5-10mm; the circumference width is 20-40° with the relative bubbling mouth as the center of the circle; the depth of the heat-insulation groove is the thickness of the base 2/5 to 1, the best is 3/5 to 4/5.

The material of the water-cooled metal box 3 is stainless steel 304 or 316, and should be degaussed after processing, and the cooling water is introduced into the cavity of the metal box by the water inlet pipe 10 and the water outlet pipe 12; the quantity of the water-cooled metal box 3 Set to 4 to 12 splits, the best is 6 or 8 splits.

The bubbling opening 16 protrudes from the upper surface of the water-cooled metal box 3 by 1-3 cm, preferably 1-2 cm.

The width of the base slit 17 is 4-15 mm, preferably 4-8 mm.

The distance between the heat insulation groove 19 and the heat conducting plate 18 is 1-5 mm.

The refractory mud is aluminosilicate, and the content of alumina in the aluminosilicate is not less than 70%, so as to ensure the refractoriness and sealing performance of the base.

The temperature controller uses a PLC combined with a touch screen to realize parameter setting, PID control, parameter display and data recording functions, and can realize dual PID switching of temperature VS power and weight VS power; the operating frequency of the intermediate frequency induction power supply is 10-20kHz, working in water-cooled or air-cooled mode; the length of the intermediate frequency induction coil 7 is preferably 1-3 cm exposed from the bottom of the coil at the lower edge of the leakage pipe; the inner diameter of the intermediate frequency induction coil 7 is the Between 1.1 and 1.3 of the outer diameter of the material leakage pipe 8 .

Utilize the discharging method of above-mentioned cold crucible high temperature glass, comprise the following steps:

1) After the glass in the cold crucible is ignited, expanded and melted, continue to add new glass beads or glass clinker to the cold crucible in batches until the rated load state is reached, and the melt temperature in the glass reaches 1150°C;

2) Set the bubbling flow rate of the bubbling port (16) to 10-80L/h, preferably 10-40L/h;

3) Adjust the cooling flow rate of the water-cooled base so that the temperature difference between the inlet and outlet water of the base is controlled at 20-40°C and does not exceed the critical temperature and pressure of the cooling water pipe;

4) Turn on the medium frequency induction heating power supply and the temperature controller, and set the heating program on the touch screen of the temperature controller: the heating rate is 20-50°C/min, when the temperature reaches 400°C, keep the temperature constant for 5-10min, and then Change the heating rate to 30-60°C/min, when it reaches 700°C, keep the temperature constant for 3-8 minutes, then change the heating rate to 30-50°C/min, when the temperature reaches _TL (glass liquidus temperature)+30-50°C time, constant temperature;

5) On the touch screen of the temperature controller, set the weight control program according to the discharge flow needs;

6) The temperature controller compares the set segmental temperature curve (SV) with the measured temperature signal (PV) of the thermocouple through the isolation transmitter, performs PID analysis, and outputs the control signal to the intermediate frequency power supply, and the intermediate frequency power supply passes through The intermediate frequency induction coil transfers the energy to the leakage pipe;

7) Open the water-cooled gate valve (9) to discharge the material to the glass storage tank. When the material is discharged and the weight signal is stable, immediately switch to weight VS power PID control, that is, the controller is based on the set segmented weight curve ( SV) is compared with the measured weight signal (PV) of the leaked glass, PID analysis is carried out, the control signal is output to the intermediate frequency power supply, and the intermediate frequency power supply transmits the energy to the leaking material tube through the induction coil, and then controls the channel of the leaking material tube (22) The discharge flow rate of high temperature glass;

8) When the weight of the glass storage tank is about to reach the target weight, first turn off the heating of the intermediate frequency power supply through PID control, and when the weight of the glass storage tank reaches the target weight, close the water-cooled gate valve (9) to complete a round of discharging material flow;

9) Continue to feed materials into the cold crucible, and after the complete melting reaches the rated glass load, proceed to the next round of discharging process.

Example 1

The inner diameter of the cold crucible is 350mm, which is made of water-cooled stainless steel; the bottom thickness of the crucible is 22mm, and the weight of the cold crucible is about 100kg when fully loaded with glass. The water-cooled metal split structure 15 has 6 splits, the slit of the base is 6 mm, the number of bubbling openings is 3, and the upper surface of the water-cooled box protrudes 2 cm. The number of heat insulation grooves located in the central area of the leakage port is designed to be 3, the radial width is 8mm, the depth is 20mm, and the arc size relative to the bubbling port as the center of the circle is 30°. The number of the heat conducting plates 18 is 3, symmetrically distributed on the inner side of the heat insulation groove 19, the radial width is 3mm, the height is 2cm, and the arc size relative to the bubbling mouth as the center of the circle is 20°. Base slit 17, heat insulation groove 19, base and crucible body are all filled with refractory mud, and the material is aluminosilicate. The content of aluminum oxide in aluminosilicate is 90%, and the content of silicon dioxide is 8%. A 690 alloy leakage tube is selected, with an outer diameter of 40mm, an inner diameter of 16mm, and a total length of 170mm. The length of the intermediate frequency coil is 100mm, and the inner diameter is 60mm. Borosilicate glass with a liquidus temperature _TL of 900°C is selected.

The feeding method of high temperature glass is as follows:

1) After the glass in the cold crucible has been ignited, expanded and melted (glass in the crucible ~50kg), continue to add new glass beads or glass clinker to the cold crucible in batches to reach a rated load of about 100kg, and the melt Internal temperature 1150℃;

2) Set the bubbling flow rate of the bubbling port to 25L/h;

3) Adjust the flow of cooling water at the base of the cold crucible to a temperature difference of about 20-25°C between the inlet and outlet water;

4) Turn on the medium frequency induction heating power supply and the temperature controller, and set the temperature rise program on the touch screen of the temperature controller, 400°C constant temperature for 5 minutes (heating rate 50°C/min), 700°C constant temperature for 3 minutes (heating rate 50°C/min), 950°C constant temperature (heating rate 50°C/min), starting temperature VS power PID control discharge program;

5) On the touch screen of the temperature controller, set the weight control program (0-10min) according to the rate of 5kg/min;

6) Open the water-cooled gate valve (9) to discharge the material into the glass storage tank. When the material is discharged and the weight signal is stable, immediately switch to weight VS power PID control;

7) After the material is released and the weight signal is stable, the controller automatically switches to weight VS power PID control;

8) When the weight of the glass storage tank reaches the target weight (50kg), the intermediate frequency power supply heating has stopped ahead of time, and the water-cooled gate valve 9 is closed to complete a material leakage operation;

9) Continue to feed materials into the cold crucible, and after the complete melting reaches the rated glass load, proceed to the next round of discharging process.

Example 2

The inner diameter of the cold crucible is 550mm, and it is made of water-cooled stainless steel curved plate; the thickness of the bottom of the crucible is designed to be 25mm, and the weight of the cold crucible is about 400kg when fully loaded with glass. The water-cooled metal box 3 is set to be divided into 8 parts, the slit 17 of the base is designed to be 8 mm, and the number of bubbling ports 16 is 4, extending 2 cm from the upper surface of the water-cooled box. The number of heat insulation grooves 19 located in the central area of the leakage opening is designed to be 4, the radial width is 10mm, the depth is 22mm, and the arc size relative to the bubbling opening as the center of the circle is 40°. The quantity of heat conduction plate is 4, is symmetrically distributed in heat insulation groove (19) inner side, and radial width is 4mm, and height is 2cm, and the radian size that is the center of circle relative to bubbling mouth is 30 °. The slit of the base, the heat insulation groove, and the space between the base and the crucible body are all filled with refractory mud, and the material is aluminosilicate. The content of aluminum oxide in aluminosilicate is 90%, and the content of silicon dioxide is 8%. A 690 alloy leakage tube is selected, with an outer diameter of 50mm, an inner diameter of 18mm, and a total length of 180mm. The length of the intermediate frequency coil is 120mm, and the inner diameter is 80mm. Borosilicate glass with a liquidus temperature _TL of 900°C is selected.

The feeding method of high temperature glass is as follows:

1) After the glass in the cold crucible has been ignited, expanded and melted (glass in the crucible ~ 200kg), continue to add new glass beads or glass clinker to the cold crucible in batches, and the glass in the crucible will reach the rated load of about 400kg. And the temperature inside the melt is 1150°C;

2) Set the bubbling flow rate of the bubbling port to 30L/h;

3) Adjust the flow of cooling water at the base of the cold crucible to a temperature difference of about 25-30°C between the inlet and outlet water;

4) Turn on the medium frequency induction heating power supply and temperature controller, and set the temperature rise program on the touch screen of the temperature controller, 400°C constant temperature for 5 minutes (heating rate 50°C/min), 700°C constant temperature for 5 minutes (heating rate 50°C/min), 950°C constant temperature (heating rate 50°C/min), starting temperature VS power PID control discharge program;

5) On the touch screen of the temperature controller, set the weight control program (0-25min) according to the rate of 8kg/min;

6) Open the water-cooled gate valve 9 to discharge the material to the glass storage tank. When the material is discharged and the weight signal is stable, immediately switch to weight VS power PID control;

7) After the material is released and the weight signal is stable, the controller automatically switches to weight VS power PID control;

8) When the weight of the glass storage tank reaches the target weight (200kg), the heating of the intermediate frequency power supply has stopped in advance, and the water-cooled gate valve is closed to complete a material leakage operation;

9) Continue to feed materials into the cold crucible, and after the complete melting reaches the rated glass load, proceed to the next round of discharging process.

Claims (12)

1. A cold crucible base, characterized in that: the water-cooled crucible base includes a leaking pipe (8), a central leaking port (14), a water-cooled metal split structure (15) and an intermediate frequency induction heating system, The central leakage opening (14) is located at the center of the water-cooled crucible base, and includes an inverted cone-shaped leakage opening and a plurality of groups symmetrically distributed from the inside to the outside relative to the inverted cone-shaped leakage opening. The heat conduction plate (18) and the heat insulation groove (19), at the lower end of the central leakage port (14), connect the leakage pipe (8) through the leakage pipe fixing flange (13), in the A temperature measuring hole (21) is provided on the outer side of the upper end of the leakage pipe (8), a water-cooled gate valve (9) is provided at the lower end of the leakage pipe (8), and a water-cooled gate valve (9) is provided at the center leakage port ( 14) is surrounded by the water-cooled metal split structure (15), and the water-cooled metal split structure (15) includes a plurality of water-cooled metal boxes (3), bubbling ports (16) and base slits (17 ), between the two water-cooled metal boxes (3) is a base slit (17), and on the upper surface of the water-cooled metal box (3) the bubbling mouth (16) is symmetrically set at half the radius of the crucible base, so The number of the bubbling ports (16) is half of the number of the water-cooled metal box (3), and the lower surface of the water-cooled metal box (3) is provided with a water inlet pipe (10) and a water outlet pipe (12), The lower surface of the water-cooled metal box (3) is also provided with an air inlet pipe (11) corresponding to the bubbling port (16), and the air inlet pipe (11) passes through the water-cooled metal box The inner cavity is connected to the bubbling mouth (16), the bubbling mouth (16) is higher than the upper surface of the water-cooled metal box (3), the connecting seam (5) between the base and the crucible body, Refractory mud is all filled in base slit (17) and heat insulation groove (19); The intermediate frequency induction heating system includes a temperature measuring thermocouple (6), an isolation transmitter, a temperature controller, an intermediate frequency induction power supply and an intermediate frequency induction coil (7), and the temperature measuring thermocouple (6) is set on the In the temperature measuring hole (21), the intermediate frequency induction coil (7) is set outside the leakage pipe (8), and the intermediate frequency induction coil (7) is powered by the intermediate frequency induction power supply. The temperature measuring thermocouple (6) is connected to the temperature controller through the isolation transmitter. 2. The cold crucible base according to claim 1, characterized in that the temperature-measuring thermocouple (6) is a high-temperature-resistant S-type thermocouple, and the thermocouple is insulated and placed in a metal sleeve to prevent High-frequency and medium-frequency electromagnetic interference, the metal sleeve of the thermocouple is made of copper or stainless steel; the temperature measurement point (21) of the temperature measurement thermocouple is close to the fixed flange (13) of the leakage tube, and It is located 5mm above the intermediate frequency induction coil (7), extends deep into the leakage pipe, and is 2-4mm away from the tapered leakage opening. 3. The cold crucible base according to claim 1, characterized in that the material of the leakage pipe (8) is 690 alloy, 310S stainless steel, 304 stainless steel or 316 stainless steel, and degaussing treatment after processing, the said The length of the leakage pipe (8) is between 100°C and 150°C based on the temperature gradient between the temperature at the thermocouple and the center of the intermediate frequency induction coil; and the upper limit temperature of the center of the leakage channel (22) of the leakage pipe (8) is not high At 1150°C, the long-term working temperature is not higher than 1100°C, and the tapered leakage port is an inverted trumpet shape with a taper of 60-150°. 4. The cold crucible base according to claim 1, characterized in that the radial width of the heat conducting plate (18) is 2-8mm; the circumference width is 20-30° with the arc as the center relative to the bubbling mouth ; The height of the heat conducting plate (18) is 1~3cm. 5. The cold crucible base according to claim 1, characterized in that the radial width of the heat insulation groove (19) is 5-15mm; the arc of the circumference with the relative bubbling mouth as the center is 20-40° ; The depth of the heat insulation groove is 2/5~1 of the thickness of the base. 6. The cold crucible base according to claim 1, characterized in that the water-cooled metal box (3) is made of stainless steel 304 or stainless steel 316, and degaussed after processing, the water inlet pipe (10), the outlet pipe (12) Lead cooling water into the cavity of the metal box; the number of the water-cooled metal box (3) is set to 4-12 splits. 7. The cold crucible base according to claim 1, characterized in that the bubbling mouth (16) protrudes 1-3 cm from the upper surface of the water-cooled metal box (3). 8. The cold crucible base structure according to claim 1, characterized in that the width of the base slit (27) is 4-15 mm. 9. The cold crucible base according to claim 1, characterized in that the distance between the heat insulation groove (19) and the heat conduction plate (18) is 1-5 mm. 10. The cold crucible base according to claim 1, characterized in that the refractory putty is aluminosilicate, and the content of alumina in the aluminosilicate is not less than 70%, so as to ensure the refractoriness and Sealing performance. 11. The cold crucible base according to claim 1, characterized in that the temperature controller uses a PLC combined with a touch screen to realize parameter setting, PID control, parameter display and data recording functions, and can realize the adjustment of power according to temperature PID control and dual PID switching of PID control based on weight to power; the operating frequency of the intermediate frequency induction power supply is 10~20kHz, and it works in water-cooled or air-cooled mode; the length of the intermediate frequency induction coil (7) is The lower edge of the material tube exposes 1-3 cm from the bottom of the coil; the inner diameter of the intermediate frequency induction coil (7) is between 1.1 and 1.3 times the outer diameter of the material leakage tube (8). 12. have the described cold crucible discharge method of the cold crucible base of claim 1, it is characterized in that: this method comprises the following steps: 1) After the glass in the cold crucible is ignited, expanded and melted, continue to add new glass beads or glass clinker to the cold crucible in batches until the rated load state is reached, and the melt temperature in the glass reaches 1150°C; 2) Set the bubbling flow rate of the bubbling port (16) to 10~80L/h; 3) Adjust the cooling flow rate of the water-cooled base so that the temperature difference between the inlet and outlet water of the base is controlled at 20-40°C and does not exceed the critical temperature and pressure of the cooling water pipe; 4) Turn on the medium frequency induction heating power supply and temperature controller; 5) Set the heating program on the touch screen of the temperature controller: the heating rate is 20~50°C/min, when the temperature reaches 400°C, keep the temperature constant for 5~10min, then change the heating rate to 30~60°C/min, When it reaches 700°C, keep the temperature constant for 3~8 minutes, then change the heating rate to 30~50°C/min, when the temperature reaches T _L +30°C~50°C, keep the temperature constant; T _L is the glass liquidus temperature; 6) On the touch screen of the temperature controller, set the weight control program according to the discharge flow needs; 7) The temperature controller compares the set segmental temperature curve (SV) with the measured temperature signal (PV) of the thermocouple through the isolation transmitter, performs PID analysis, and outputs the control signal to the intermediate frequency power supply, and the intermediate frequency power supply passes through The induction coil transfers the energy to the leakage pipe; 8) Open the water-cooled gate valve (9) to discharge the material to the glass storage tank. When the material is discharged and the weight signal is stable, immediately switch to the PID control of the power based on the weight, that is, the controller is based on the set segment weight. The curve (SV) is compared with the measured weight signal (PV) of the leaked glass, and the PID analysis is carried out, and the control signal is output to the intermediate frequency power supply, and the intermediate frequency power supply transmits the energy to the leakage pipe through the induction coil, and then controls the leaking pipe channel ( 22) The discharge flow rate of high temperature glass; 9) When the weight of the glass storage tank reaches the target weight, first turn off the intermediate frequency power heating through PID control, and when the weight of the glass storage tank reaches the target weight, close the water-cooled gate valve (9) to complete a round of discharge material flow; Continue to feed materials into the cold crucible, and after the complete melting reaches the rated glass load, the next round of feeding process will be carried out.

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