Multifunctional single-tube air-blowing liquid level measuring device and its usage method

Abstract

A multifunctional single-tube air-blowing liquid level measuring device includes an air-blowing system, a water-cooled measuring rod, and a control system. The air-blowing system consists of an air source, a pressure reducing valve, a flow meter, and an air guide pipe. The water-cooled measuring rod consists of an inlet chamber, an outlet chamber, a water-cooled inner tube, a water-cooled outer tube, an end air guide port, and inlet and outlet water pipes. The control system consists of a pressure transmitter, a programmable logic controller (PLC), and a touch screen. The lower end of the water-cooled measuring rod adopts an inverted flared design to prevent the end air guide port from being blocked due to an excessively thick cold shell, while ensuring sufficient cooling effect. The water-cooled measuring rod is cooled by high-temperature cooling water, which can significantly reduce the condensation of gaseous components above the melt, thereby effectively reducing gas phase corrosion and ensuring long-term reliable operation of the liquid level measuring device. Simultaneously, during melting and charging, the air-blowing liquid level measuring device can also be used as a bubbler for molten glass, helping to improve the melting and charging efficiency of the cold crucible and reduce precious metal deposition.

Description

Technical Field

[0001] This invention relates to the field of nuclear waste vitrification, specifically to a multifunctional single-tube blowing liquid level measuring device and its usage method for measuring the liquid level of glass melt and bubbling devices. Background Technology

[0002] In the engineering application of cold crucible glass solidification, glass solidification is an intermittent feeding and leaking process, requiring accurate measurement of the temperature and level of the molten glass to ensure the smooth progress of the solidification process. Monitoring and controlling the molten glass level is one of the challenges in glass solidification technology. Nuclear waste glass is highly corrosive at high temperatures, including both gas and liquid phase corrosion, which places high demands on the material selection of the level gauge and the cooling method. Meanwhile, in the cold crucible glass solidification process, bottom venting and bubbling combined with top water-cooled mechanical stirring are typically used to improve the melting and homogenization efficiency of the glass and prevent the deposition of precious metals. However, the complex mechanical design of the water-cooled mechanical stirring mechanism increases the assembly difficulty of the crucible top structure. Furthermore, the metal material of the stirring paddle is susceptible to corrosion from the gas and liquid phases of the high-temperature glass, resulting in poor reliability.

[0003] Glass level monitoring technologies mainly include high-frequency probe level gauges, bell-type level gauges, and air-purge differential pressure level gauges. Among these, the air-purge differential pressure level gauge is also known as a purge level gauge. Purge level gauges are divided into single-tube and double-tube types, with the double-tube type being the most common in the glass curing field. In Joule furnace applications, the level gauge material is typically Inconel 690, lacking a water-cooling structure. This material is inevitably subject to corrosion from the gas and liquid phases of radioactive glass, resulting in a relatively short lifespan. The compact structure and limited operating space of cold crucibles restrict the application of double-tube level gauges.

[0004] A French nuclear fuel company and the Atomic Energy Commission (CEA) have disclosed a measuring rod (CN1474936A) for measuring the height of a molten liquid pool. This measuring rod has cooling water at 20°C circulating inside and outside the vent pipe, allowing it to operate under the protection of a cold shell. While the portion of the measuring rod in contact with the molten glass is protected by a cold shell of a few millimeters at this temperature, resulting in relatively low corrosion, the temperature difference causes gaseous components from above the molten glass to easily condense on the measuring rod, potentially accelerating corrosion of the material after prolonged use. Furthermore, the lower end of the measuring rod has a straight-hole structure for the vent, which is easily blocked by the cold glass shell under cooling water (resulting in very low bubbling flow), ultimately causing the liquid level monitoring function to fail. In addition, this invention does not explicitly provide a specific method for measuring the liquid level.

[0005] Taijia Glass Fiber Co., Ltd. in China has disclosed a device and method for detecting liquid level changes in glass furnaces (CN111928921A). This device includes an air blowing device, a differential pressure transmitter, an air blowing pipeline, a probe, and a liquid level change judgment unit. The liquid level measuring probe is a single-tube type, with a relatively simple and practical structure and reliable measurement results. However, this invention does not specify the probe material, lacks a surrounding water-cooling structure, and relies solely on a small amount of air blowing for cooling, which cannot alleviate the high-temperature gas and liquid phase corrosion of radioactive waste glass. Furthermore, the liquid level change is mainly obtained through the pressure difference over different measurement times, without explaining how the actual glass liquid level is obtained. Summary of the Invention

[0006] To overcome the shortcomings of existing air-blowing level gauges, this invention discloses a multifunctional single-tube air-blowing level measuring device that can be used simultaneously for measuring the level of corrosive glass and for top bubbling. During startup and melting, it can replace mechanical stirring to homogenize the glass melt and prevent the deposition of precious metals. In other processes, it can be used for level measurement. Its application areas include, but are not limited to, Joule-heated ceramic furnaces and cold crucible induction-heated furnaces.

[0007] The technical solution of the present invention is as follows:

[0008] A multifunctional single-tube air-blowing liquid level measuring device is characterized in that the device includes an air-blowing system, a water-cooled measuring rod, and a control system. The air-blowing system consists of an air inlet of an air source, a pressure reducing valve, a flow meter, and an air guide pipe connected in sequence. The water-cooled measuring rod consists of a water inlet chamber, a water outlet chamber, a water-cooled inner tube, a water-cooled outer tube, an end air guide port, a water inlet pipe, and a water outlet pipe. One end of the water-cooled inner tube is connected to the water inlet chamber and surrounds the air guide pipe. The upper end of the water-cooled outer tube is connected to the water outlet chamber and surrounds the water-cooled inner tube. The lower end of the water-cooled outer tube is connected to the water outlet chamber. The pipes are connected, and the end air inlet is a metal structure tightly welded to the lower end of the water-cooled measuring rod, shaped like an inverted trumpet. The water inlet chamber and water outlet chamber are respectively connected to the water inlet pipe and the water outlet pipe. The control system consists of a touch screen, a programmable controller, and a pressure transmitter in sequence. The input end of the air inlet pipe is connected to the flow meter, and the output end of the pressure transmitter is connected to the air inlet pipe. The other end of the air inlet pipe is fixedly connected to the end air inlet through the water-cooled measuring rod. The water-cooled measuring rod is directly inserted into the molten glass, and the outer diameter of the air inlet pipe is controlled within 10mm.

[0009] The volume of the outlet chamber is 10-30% larger than that of the inlet chamber, with 20% being optimal.

[0010] The water-cooled inner tube and water-cooled outer tube of the water-cooled measuring rod are channels through which cooling water flows. The material is stainless steel 304, 316 or 690 alloy. Cooling water flows in from the cavity between the water inlet chamber, the air guide pipe and the water-cooled inner tube, flows through the lower end of the water-cooled inner tube into the cavity between the water-cooled outer tube and the water-cooled inner tube, and finally flows out of the water-cooled measuring rod through the water outlet chamber and the water outlet pipe.

[0011] The outer diameter of the water-cooled outer tube is generally no more than 40mm, and preferably within 30mm.

[0012] The angle of the lower end of the end air vent is 20-60°, preferably 20-30°. The height of the end air vent is 10-40mm, preferably 20-30mm. The material of the end air vent is 690 alloy, 316 stainless steel, or 310S stainless steel, preferably 690 alloy.

[0013] The inlet water temperature of the cooling water is 60-80℃, with the optimal temperature being 70-80℃.

[0014] The gas source is compressed air, nitrogen, or argon. The type of gas is selected according to the process requirements. When a weak reducing atmosphere or an inert atmosphere is required, nitrogen or argon is preferred, and when an oxidizing atmosphere is required, compressed air is preferred.

[0015] During melting and feeding, the multifunctional single-tube blowing liquid level measuring device switches its function to a bubbler for the glass melt, which is used to improve the homogenization efficiency of the glass melt and reduce the deposition of precious metals.

[0016] The method of using the above-mentioned multifunctional single-tube air-blowing liquid level measuring device includes the following steps:

[0017] 1) Turn on the cooling water switch to ensure the water flow rate of the water-cooled measuring rod is between 0.1 and 0.6 m³ / s. 3 / h, inlet and outlet pressure difference ≥0.2MPa;

[0018] 2) Turn on the gas source and adjust the pressure reducing valve to maintain the pressure at 0.15-0.25 MPa;

[0019] 3) Turn on the gas flow meter. During bubbling and melting, the gas flow rate is set to 100-200 L / h. During liquid level measurement, the gas flow rate is set to 50-100 L / h.

[0020] 4) Fill the cold crucible with enough glass to start the ignition. After ignition, lower the water-cooled measuring rod below the surface of the molten glass and keep the lower edge of the gas inlet at the end of the rod 2-5 cm away from the unmelted glass at the bottom of the cold crucible for bubbling and diffusion melting.

[0021] 5) After the glass melt has completed its expansion melting, lower the water-cooled measuring rod to 3-6 cm from the bottom of the cold crucible, start adding material and begin bubbling the melting material;

[0022] 6) After the melting is completed, reduce the bubbling flow rate to the set range and measure the liquid level. Monitor the bubbling rate of the glass liquid surface with a dedicated high-temperature camera. When the number of bubbles is maintained at 1 to 2 bubbles per second, the hardware part of the liquid level measuring device is put into operation.

[0023] 7) The programmable controller collects the pressure at the top of the cold crucible and the pressure signal read by the pressure transmitter. After filtering, it calculates the real-time liquid level of the glass melt according to the preset program. After reaching the upper limit liquid level, the material leakage begins.

[0024] 8) When the lower limit liquid level is reached, stop the leakage and start a new round of feeding process, increase the bubbling flow rate to the set range. At this time, the function of the liquid level measuring device is automatically switched to bubbler.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] (1) The lower end of this water-cooled measuring rod adopts an inverted flared design to ensure sufficient cooling effect while preventing the end air vent from being blocked due to excessively thick cold shell.

[0027] (2) This water-cooled measuring rod is cooled by high-temperature cooling water. Compared with room temperature cooling water, it can reduce the condensation of the gas phase above the melt, alleviate the erosion of the measuring rod surface by the gas phase components, and ensure that the liquid level measuring device can work reliably for a long time.

[0028] (3) This liquid level measuring device can directly read the real-time liquid level of high temperature glass, which is convenient to use and has good operability; (4) During melting and feeding, the bubbling flow rate is increased. This multi-functional single-tube blowing liquid level measuring device can also replace the top mechanical stirrer used for glass liquid bubbling, which helps to improve the homogenization efficiency of glass liquid and reduce precious metal deposition. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the measurement principle of a multifunctional single-tube air-blowing liquid level measuring device.

[0030] Figure 2 This is a schematic diagram of the system structure of a multifunctional single-tube air-blowing liquid level measuring device.

[0031] In the diagram: 1—Gas source / inlet; 2—Pressure reducing valve; 3—Flow meter; 4—Pressure transmitter; 5—Gas pipe; 6—Water-cooled measuring rod; 7—Cold crucible; 8—Vacuum pressure gauge; 9—Furnace cavity; 10—Molten glass; 11—Water inlet chamber; 12—Water outlet chamber; 13—Water-cooled inner pipe; 14—Water-cooled outer pipe; 15—End gas inlet; 16—Water inlet pipe; 16'—Water outlet pipe; 17—Programmable logic controller (PLC); 18—Touch screen. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments and accompanying drawings, but this should not be construed as limiting the scope of protection of the present invention.

[0033] The measurement principle of the multifunctional single-tube air-blowing liquid level measuring device of the present invention is as follows: Figure 1 As shown, the specific explanation is as follows:

[0034] A multifunctional single-tube air-blowing liquid level measuring device includes an air-blowing system, a water-cooled measuring rod 6, and a control system. The air-blowing system consists of an air source 1, a pressure reducing valve 2, a flow meter 3, and an air guide pipe 5 connected in sequence. The water-cooled measuring rod 6 consists of an inlet chamber 11, an outlet chamber 12, a water-cooled inner tube 13, a water-cooled outer tube 14, an end air guide port 15, an inlet pipe 16, and an outlet pipe 16'. One end of the water-cooled inner tube 13 is connected to the inlet chamber 11 and surrounds the air guide pipe 5. The upper end of the water-cooled outer tube 14 is connected to the outlet chamber 12 and surrounds the water-cooled inner tube 13. The lower end of the water-cooled outer tube 14 is connected to the outlet chamber 12. The water-cooled inner tube 13 is connected, and the end air inlet 15 is a metal structure tightly welded to the lower end of the water-cooled measuring rod 6, which is in the shape of an inverted trumpet. The water inlet chamber 11 and the water outlet chamber 12 are respectively connected to the water inlet pipe 16 and the water outlet pipe 16'. The control system consists of a touch screen 18, a programmable controller 17 and a pressure transmitter 4 in sequence. The input end of the air inlet pipe 5 is connected to the outlet end of the flow meter 3, and the output end of the pressure transmitter 4 is connected to the air inlet pipe 5. The other end of the air inlet pipe 5 is fixedly connected to the end air inlet 15 through the water-cooled measuring rod 6. The water-cooled measuring rod 6 can be directly inserted into the molten glass liquid 10.

[0035] The volume of the outlet chamber 12 is 10-30% larger than the volume of the inlet chamber 11, with the optimal value being 20%. The outer diameter of the pressure transmitter 4 is controlled within 10mm.

[0036] The water-cooled inner tube 13 and water-cooled outer tube 14 of the water-cooled measuring rod 6 are channels through which cooling water flows. The material is stainless steel 304, 316 or 690 alloy. Cooling water flows into the cavity between the water inlet pipe 16, water inlet chamber 11, air guide pipe 5 and water-cooled inner tube 13, flows into the cavity between the water-cooled outer tube 14 and water-cooled inner tube 13 through the lower end of the water-cooled inner tube 13, and finally flows out of the water-cooled measuring rod 6 through the water outlet chamber 12 and water outlet pipe 16'.

[0037] The outer diameter of the water-cooled outer tube 14 is generally no more than 40 mm, and preferably within 30 mm.

[0038] The angle of the lower end of the end air vent 15 is 20-60°, preferably 20-30°. The height of the end air vent 15 is 10-40mm, preferably 20-30mm. The material of the end air vent 15 is 690 alloy, stainless steel 316 or stainless steel 310S, preferably 690 alloy.

[0039] The inlet water temperature of the high-temperature cooling water is 60-80℃, with an optimal temperature of 70-80℃.

[0040] The gas source 1 is compressed air, nitrogen, or argon. The type of gas is selected according to the process requirements. When a weak reducing atmosphere or an inert atmosphere is required, nitrogen or argon is preferred, and when an oxidizing atmosphere is required, compressed air is preferred.

[0041] During melting and feeding, the liquid level measuring device switches to function as a bubbler for the molten glass, which improves the homogenization efficiency of the molten glass and reduces the deposition of precious metals.

[0042] The method of using the above-mentioned multifunctional single-tube air-blowing liquid level measuring device includes the following steps:

[0043] 1) Turn on the cooling water switch to ensure the water flow rate of the water-cooled measuring rod 6 is between 0.1 and 0.6 m³ / s. 3 / h, inlet and outlet water pressure difference ≥0.2MPa;

[0044] 2) Turn on the gas source 1 and adjust the pressure reducing valve 2 to maintain the pressure at 0.15-0.25 MPa;

[0045] 3) Turn on the gas flow meter 3, and set the gas flow rate range during bubbling and melting to 100-200 L / h, and the gas flow rate during liquid level measurement to 50-100 L / h;

[0046] 4) Fill the cold crucible 7 with enough glass to start the ignition. After ignition, lower the water-cooled measuring rod 6 below the glass liquid level and keep the lower edge of its end air inlet 15 2-5 cm away from the bottom of the unmelted glass in the cold crucible 7 for bubbling and diffusion melting.

[0047] 5) After the glass melt has completed its expansion melting, the water-cooled measuring rod 6 is lowered to 3-6 cm from the bottom of the cold crucible 7, and the material is added and bubbled melting is started;

[0048] 6) After the melting is completed, reduce the bubbling flow rate to the set range and measure the liquid level. Monitor the bubbling rate of the glass liquid surface with a dedicated high-temperature camera. When the number of bubbles is maintained at 1 to 2 bubbles per second, the hardware part of the liquid level measuring device is put into operation.

[0049] 7) The programmable controller collects the pressure from the vacuum pressure gauge 8 set on the upper part of the cold crucible 7 and the pressure signal read by the pressure transmitter. After filtering, it calculates the real-time liquid level of the glass melt according to the preset program. After reaching the upper limit liquid level, the material leakage begins.

[0050] 8) When the lower limit liquid level is reached, stop the leakage and start a new round of feeding process, increase the bubbling flow rate to the set range. At this time, the function of the liquid level measuring device is automatically switched to bubbler.

[0051] Example

[0052] After being filtered and depressurized, the gas enters the blowing device and is constantly bubbled out from the end (point B) of the blowing pipe, which is inserted into the molten glass 10 being tested, via the gas guide pipe 5. Because the gas flow rate from the blowing pipe is very small, the gas pressure P at point B is... B If the pressure at point A is equal to the pressure of the molten glass, then the gas pressure P is equal to the pressure of the molten glass. A equals P B Adding the pressure difference ΔP between points A and B AB The gas pressure P at point C in the furnace cavity 9 above the glass melt C The pressure was measured by vacuum pressure gauge 8 from cold crucible 7. To calculate the pressure difference ΔP between points A and B... AB First, in an atmospheric environment, water is used as the measured medium, i.e., P. C Equivalent to the local atmospheric pressure, multiple bubbling tests were conducted at known liquid levels to calculate the pressure difference ΔP between points A and B. AB Finally, during the glass melt measurement process, the pressure reading P from the pressure transmitter can be used as a reference. A , and ρ, P C and ΔP AB The real-time liquid level is calculated as shown in equations (1)-(4):

[0053] P A =P B +ΔP AB (1)

[0054] P B =ρgh+P C (2)

[0055] P A =ρgh+P C +ΔP AB (3)

[0056] h=(P A -P C -ΔP AB ) / (ρg) (4)

[0057] In the formula, P A —Transmitter pressure, Pa; P B —Melt pressure, Pa; P C —Pressure inside the furnace cavity, Pa; ΔP AB —Pressure difference between points A and B, Pa; ρ—density of the liquid (melted glass), kg / m³ 3 g—acceleration due to gravity, m / s² 2 .

[0058] A multifunctional single-tube air-blowing liquid level measuring device includes an air-blowing system, a water-cooled measuring rod, and a control system. The air-blowing system consists of an air source 1, a pressure reducing valve 2, a flow meter 3, and an air guide pipe 5. The water-cooled measuring rod 6 consists of an inlet chamber 11, an outlet chamber 12, a water-cooled inner tube 13, a water-cooled outer tube 14, an end air guide port 15, an inlet pipe 16, and an outlet pipe 16'. The control system consists of a pressure transmitter 4, an industrial automatic control device (referred to as a programmable logic controller) 17, and a touch screen 18.

[0059] One end of the gas guide tube 5 is connected to the flow meter 3, and the other end is directly inserted into the molten glass liquid 10. Its outer diameter is controlled within 10mm to ensure that the space occupied by the water-cooled measuring rod 6 is minimized.

[0060] The volume of the outlet chamber 12 is slightly larger than that of the inlet chamber 11 by 10% to 30%, with an optimal value of 20%, to ensure that the pressure difference between the inlet and outlet water is greater than or equal to 0.2 MPa. The purpose is to reduce the resistance to water flow and ensure smooth flow.

[0061] The water-cooled inner tube 13 and water-cooled outer tube 14 are channels through which cooling water flows. They are made of stainless steel 304, 316 or 690 alloy. Cooling water flows into the cavity between the air guide tube 5 and the water-cooled inner tube 13, flows into the cavity between the water-cooled outer tube 14 and the water-cooled inner tube 13 through the lower end of the water-cooled inner tube 13, and finally flows out of the water-cooled measuring rod 6 through the water outlet cavity 12.

[0062] The outer diameter of the water-cooled outer tube 14 is generally no more than 40mm, and preferably within 30mm. This ensures that there is sufficient space for water inlet and outlet while also minimizing the space it occupies.

[0063] The aforementioned end air inlet 15 is a metal structure welded tightly to the lower end of the water-cooled measuring rod, and has an inverted trumpet shape with an angle of 20-60°, the optimal angle being 20-30°.

[0064] The height of the end air inlet 15 is 10-40mm, with an optimal height of 20-30mm. If the length is too long, the end cooling effect is poor, and if the cold shell is too thin or even nonexistent, it is easily corroded by the liquid phase glass. If the length is too short, the cooling effect is good, but the cold shell is too thick and can easily block the end air inlet, causing the water-cooled measuring rod to malfunction.

[0065] The end air inlet 15 is made of 690 alloy, stainless steel 316, or stainless steel 310S, with 690 alloy being the most suitable.

[0066] The inlet temperature of the cooling water is 60-80℃, with 70-80℃ being optimal. If the inlet temperature is too low, the cold shell around the outer tube inside the melt will be too thick, which can easily lead to bridging after long-term operation; the gaseous components above the melt are prone to condensation around the outer tube, making it susceptible to gaseous corrosion after long-term operation.

[0067] The gas source 1 of the blowing system can be compressed air, nitrogen or argon. The type of gas is selected according to the process requirements. When a weak reducing atmosphere or an inert atmosphere is required, nitrogen or argon is preferred, and when an oxidizing atmosphere is required, compressed air is preferred.

[0068] The multifunctional single-tube blowing liquid level measuring device described above switches its function as a bubbler for molten glass during melting expansion and feeding, thereby improving the homogenization efficiency of molten glass and reducing precious metal deposition.

[0069] The above-mentioned multifunctional single-tube air-blowing liquid level measuring device includes the following steps:

[0070] 1) Turn on the cooling water switch to ensure that the water flow rate of the water-cooled measuring rod is between 0.1 and 0.6 m³ / h and the inlet and outlet water pressure difference is ≥0.2 MPa;

[0071] 2) Turn on air source 1 and adjust the pressure reducing valve to maintain the pressure at 0.15-0.25 MPa;

[0072] 3) Turn on the gas flow meter 3. Set the gas flow rate range to 100-200 L / h during bubbling and melting, and set the flow rate to 50-100 L / h during liquid level measurement.

[0073] 4) Fill the cold crucible 7 with enough glass to start the ignition. After ignition, lower the water-cooled measuring rod 6 below the glass liquid level and keep the lower edge of its end gas inlet 2-5 cm away from the unmelted glass at the bottom of the cold crucible 7 to perform bubbling and diffusion melting.

[0074] 5) After the glass melt has completed its expansion melting, lower the water-cooled measuring rod to 3-6 cm from the bottom of the cold crucible 7, and start adding material and bubbling the melting material;

[0075] 6) After the melting is completed, reduce the bubbling flow rate to the set range and measure the liquid level. Monitor the bubbling rate of the glass liquid surface with a dedicated high-temperature camera. When the number of bubbles is maintained at 1 to 2 bubbles per second, the hardware part of the liquid level measuring device is put into operation.

[0076] 7) The pressure in the upper furnace chamber 9 of the cold crucible is collected by the programmable controller and the pressure signal read by the pressure transmitter. After filtering, the real-time liquid level of the glass melt is calculated according to the preset program. After the upper limit liquid level is reached, the material leakage begins.

[0077] 8) When the lower limit liquid level is reached, stop the leakage and start a new round of feeding process, increase the bubbling flow rate to the set range, and at this time the liquid level measuring device automatically switches to the bubbler function.

[0078] Example 1:

[0079] 316 stainless steel is selected as the material for the water-cooled outer tube 14, the water-cooled inner tube 13, and the gas guide tube 5, while the end gas guide port 15 is made of 690 alloy. The outer diameter of the water-cooled outer tube 14 is 30mm, the total length of the vertical section is 1200mm, and the length extending into the cold crucible 7 is 800mm. The inlet water temperature is set to 70℃, and the density of the molten glass is 2500kg / m³. 3 .

[0080] Instructions for use of the multi-functional single-tube air-blowing liquid level measuring device:

[0081] (1) Turn on the cooling water switch to ensure the water flow rate of the water-cooled measuring rod 6 is 0.3m. 3 / h, the inlet and outlet pressure difference is 0.2MPa;

[0082] (2) Turn on air source 1 (compressed air) and adjust the pressure reducing valve to maintain the pressure at 0.2MPa;

[0083] (3) Fill the cold crucible 7 with enough glass to start the fire and complete the start-up heating (ignition);

[0084] (4) Turn on the flow meter 3, maintain the flow rate at 150L / h, and lower the water-cooled measuring rod 6 to 3cm away from the bottom unmelted glass to start bubbling and melting.

[0085] (5) After the glass has completed the expansion melting, lower the water-cooled measuring rod 6 to 6cm from the bottom of the cold crucible 7 and start adding material;

[0086] (6) After the glass has been melted and homogenized, adjust the flow meter 3 to maintain the flow rate at 60L / h. Monitor the bubbling rate of the glass liquid surface with a dedicated high-temperature camera. When the bubbling is maintained at 1 to 2 bubbles per second, the hardware part of the liquid level measuring device is put into operation.

[0087] (7) Set the filtering time of the programmable controller 17 to 3s. At this time, the glass liquid level is 33.0cm and the leakage begins.

[0088] (8) After the first round of material leakage is completed, the glass liquid level drops to 22.1cm;

[0089] (9) Start a new round of feeding process and increase the bubbling flow rate to 150L / h. At this time, the function of the liquid level measuring device will automatically switch to bubbler.

[0090] During the liquid level measurement, the liquid level reading remained stable, and the actual weight of the glass discharged to the bottom receiving tank differed from the weight of the glass calculated from the liquid level change by less than 0.5%. During the glass melting process, compared with non-bubbling melting, bubbling melting can improve melting efficiency and reduce melting time by more than 1 hour; during a single round of melting, bubbling melting efficiency can shorten melting time by more than 0.5 hours.

[0091] Experiments show that the lower end of the water-cooled measuring rod adopts an inverted flared design, which, while ensuring sufficient cooling effect, prevents the end vent from being blocked due to an excessively thick cold shell. The water-cooled measuring rod uses high-temperature cooling water, which significantly reduces the condensation of gaseous components above the melt, thereby effectively reducing vapor phase corrosion and ensuring the long-term reliable operation of the liquid level measuring device. Simultaneously, during melting and charging, the blowing liquid level measuring device can also be used as a bubbler for the glass melt, helping to improve the melting and charging efficiency of the cold crucible and reduce precious metal deposition.

Claims

1. A multifunctional single-tube air-blowing liquid level measuring device, characterized in that... The device includes an air blowing system, a water-cooled measuring rod (6), and a control system. The air blowing system consists of an air source (1), a pressure reducing valve (2), a flow meter (3), and an air guide pipe (5) connected in sequence. The water-cooled measuring rod (6) consists of an inlet chamber (11), an outlet chamber (12), a water-cooled inner tube (13), a water-cooled outer tube (14), an end air guide port (15), an inlet pipe (16), and an outlet pipe (16'). One end of the water-cooled inner tube (13) is connected to the inlet chamber (11) and surrounds the air guide pipe (5). The upper end of the water-cooled outer tube (14) is connected to the outlet chamber (12). The water-cooled outer tube (14) surrounds the water-cooled inner tube (13), and the lower end of the water-cooled outer tube (14) is connected to the outlet chamber (5). The water-cooled inner tube (13) is connected to the end air inlet (15), which is a metal structure close to the lower end of the water-cooled measuring rod (6) and is in the shape of an inverted trumpet. The water inlet chamber (11) and the water outlet chamber (12) are connected to the water inlet pipe (16) and the water outlet pipe (16') respectively. The control system consists of a touch screen (18), a programmable controller (17) and a pressure transmitter (4) in sequence. The input end of the air inlet tube (5) is connected to the outlet end of the flow meter (3), and the output end of the pressure transmitter (4) is connected to the air inlet tube (5). The other end of the air inlet tube (5) is connected to the end air inlet (15) of the water-cooled measuring rod (6). The water-cooled measuring rod (6) is inserted into the molten glass liquid (10).

2. The multifunctional single-tube air-blowing liquid level measuring device according to claim 1, characterized in that, The volume of the water outlet chamber (12) is 10-30% larger than the volume of the water inlet chamber (11), with the optimal value being 20%. The outer diameter of the air guide tube (5) is controlled within 10 mm.

3. The multifunctional single-tube air-blowing liquid level measuring device according to claim 1, characterized in that, The water-cooled inner tube (13) and water-cooled outer tube (14) are channels through which cooling water flows. They are made of stainless steel 304, 316 or 690 alloy. Cooling water flows into the cavity between the water inlet pipe (16), water inlet chamber (11), air guide pipe (5) and water-cooled inner tube (13), flows into the cavity between the water-cooled outer tube (14) and water-cooled inner tube (13) through the lower end of the water-cooled inner tube (13), and finally flows out through the water outlet chamber (12) and water outlet pipe (16').

4. The multifunctional single-tube air-blowing liquid level measuring device according to claim 1, characterized in that, The outer diameter of the water-cooled outer tube (14) is generally no more than 40 mm, and preferably no more than 30 mm.

5. The multifunctional single-tube air-blowing liquid level measuring device according to claim 1, characterized in that, The angle of the lower end of the end air duct (15) is 20-60°, preferably 20-30°. The height of the end air duct (15) is 10-40mm, preferably 20-30mm. The material of the end air duct (15) is 690 alloy, stainless steel 316 or stainless steel 310S, preferably 690 alloy.

6. The multifunctional single-tube air-blowing liquid level measuring device according to claim 3, characterized in that, The inlet water temperature of the cooling water is 60-80℃, with the optimal temperature being 70-80℃.

7. The multifunctional single-tube air-blowing liquid level measuring device according to claim 1, characterized in that, The gas source is compressed air, nitrogen, or argon. The type of gas is selected according to the process requirements. When a weak reducing atmosphere or an inert atmosphere is required, nitrogen or argon is preferred, and when an oxidizing atmosphere is required, compressed air is preferred.

8. The multifunctional single-tube air-blowing liquid level measuring device according to claim 1, characterized in that, During melting and feeding, the liquid level measuring device switches to function as a bubbler for the molten glass.

9. The method of using the multifunctional single-tube air-blowing liquid level measuring device according to any one of claims 1 to 8, characterized in that the method includes the following steps: 1) Turn on the cooling water switch to ensure the water flow rate of the water-cooled measuring rod (6) is between 0.1 and 0.6 m³ / s. 3 / h, inlet and outlet water pressure difference ≥0.2MPa; 2) Turn on the gas source (1) and adjust the pressure reducing valve (2) to maintain the pressure at 0.15-0.25 MPa; 3) Turn on the flow meter (3), and set the gas flow rate range to 100-200 L / h during bubbling and melting and during liquid level measurement. 4) After igniting the glass in the cold crucible (7), lower the water-cooled measuring rod (6) below the glass liquid surface and keep the lower edge of the gas inlet (15) at 2-5 cm away from the bottom unmelted glass for bubbling and diffusion melting. 5) After the glass melt has completed its expansion melting, lower the water-cooled measuring rod (6) to a distance of 3-6 cm from the bottom of the cold crucible (7), and start adding material and bubbling the melting material; 6) After the melting process is complete, reduce the bubbling flow rate to the set range, measure the liquid level, and monitor the bubbling rate of the glass liquid surface using a high-temperature camera; 7) The programmable controller (17) reads the pressure signal from the vacuum pressure gauge (8) set in the upper furnace cavity (9) of the cold crucible (7) and the pressure signal read by the pressure transmitter (4), and after filtering, calculates the real-time liquid level of the glass melt according to the preset program. After reaching the upper limit liquid level, the material leakage begins. 8) When the lower limit liquid level is reached, stop the leakage and start a new round of feeding process, increase the bubbling flow rate to the set range. At this time, the function of the liquid level measuring device is automatically switched to bubbler.

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