Automatic feeding system for granular silicon and control method thereof

Abstract

The application discloses a kind of automatic feeding system of granular silicon and its control method, the system includes single crystal furnace and is set in single crystal furnace crucible, the crucible is liftable structure, the system further includes: flow guide cylinder, the flow guide cylinder is set in the inner wall top of single crystal furnace along vertical direction, the top end of the flow guide cylinder is communicated to the outside of single crystal furnace, and the bottom end of the flow guide cylinder extends to the just above crucible;Storage tank, the storage tank is set in the position of single crystal furnace top opposite flow guide cylinder, the bottom of the storage tank is communicated to the inside of single crystal furnace by a quartz tube passing through flow guide cylinder, and the lower edge of the quartz tube is flush with the lower edge of flow guide cylinder, the feeding amount of the present application is stable and controllable, and falls in the high temperature zone closest to heater, reasonably utilizes heat energy, avoids the accident caused by sudden rise of liquid level.

Description

Technical Field

[0001] This invention relates to an automatic feeding system for granular silicon and its control method, belonging to the field of RCZ feeding technology. Background Technology

[0002] Currently, the standard RCZ feeding method is as follows: Figure 1 As shown, a quartz feeding tank with an outer diameter of 0.3m and a height of 2m is used. The feeding tank is manually raised and lowered, and its opening position is manually controlled. Silicon material is allowed to fall into the silicon solution from the top. 60-80kg is added each time, for a total of five additions.

[0003] Conventional RCZ feeding has the following drawbacks:

[0004] 1. The use of irregular blocks of 10-50mm in the single crystal furnace makes it easier to puncture the softened quartz crucible, causing silicon leakage and accidents.

[0005] 2. During conventional feeding, the silicon block falls from a height of more than 2 meters, splashing out a large amount of molten silicon, which not only contaminates the hot zone but also easily causes accidents.

[0006] 3. For conventional manual feeding, strict control must be maintained over the height of the liquid level and the upper thermal field to prevent the liquid level from rising suddenly, causing the molten silicon to wet the upper thermal field, contaminating the molten silicon, and causing an accident.

[0007] 4. Conventional manual feeding wastes a lot of time and electricity. It takes 3-5 hours for the crystal rod to leave the liquid surface and be taken out of the furnace, and the hot zone is in an unloaded state. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide an automatic feeding system for granular silicon and its control method. The feeding amount is stable and controllable, and falls in the high-temperature zone closest to the heater, making reasonable use of thermal energy and avoiding accidents caused by sudden rise in liquid level.

[0009] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0010] In a first aspect, the present invention provides an automatic feeding system for granular silicon, comprising a single crystal furnace and a crucible disposed within the single crystal furnace, wherein the crucible has a liftable structure, and the system further comprises:

[0011] A flow guide tube is vertically disposed on the top of the inner wall of the single crystal furnace. The top end of the flow guide tube is connected to the outside of the single crystal furnace, and the bottom end of the flow guide tube extends to the top of the crucible.

[0012] A storage tank is located at the top of the single crystal furnace, directly opposite the guide tube. The bottom of the storage tank is connected to the interior of the single crystal furnace through a quartz tube passing through the guide tube, and the lower edge of the quartz tube is flush with the lower edge of the guide tube.

[0013] The liquid outlet distance adjustment module is used to measure the actual liquid outlet distance through dual cameras pre-set above the single crystal furnace body. When the actual liquid outlet distance is less than the set liquid outlet distance, the system issues an alarm to prompt whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. The liquid outlet distance is the distance from the liquid surface to the guide tube.

[0014] The feeding speed adjustment module is used to measure the area ratio of the liquid in the crucible by a rangefinder set above the side of the single crystal furnace body, and adjust the feeding speed according to the area ratio of the liquid. When the actual liquid area ratio is less than the set liquid area ratio, the feeding is stopped and an alarm is triggered.

[0015] The temperature detection module is used to detect the liquid surface temperature by using an infrared thermometer pre-set above the single crystal furnace. When the area ratio of the liquid in the crucible is 100% and the liquid surface temperature exceeds the set value, the melting is completed.

[0016] Furthermore, in the liquid outlet distance adjustment module, when prompted whether to lower the crucible position, if "yes" is clicked, the crucible position will be lowered to a distance greater than the set liquid outlet distance; if "no" is clicked, feeding will stop.

[0017] Furthermore, the method for measuring the actual liquid outlet distance in the liquid outlet distance adjustment module includes:

[0018] Measure the reflection L of the guide tube on the liquid surface, and then multiply it by the angle ð of the guide tube to obtain the liquid outlet distance Z = L * tgð.

[0019] Furthermore, in the feeding speed adjustment module, the method for measuring the surface area ratio of the liquid in the crucible includes:

[0020] Measure the diameter of the crucible and calculate the total surface area of ​​the liquid based on the crucible diameter;

[0021] The area of ​​the solid on the liquid surface is measured, and the solid area is compared with the total liquid surface area to obtain the solid area ratio. The liquid area ratio is then calculated based on the solid area ratio.

[0022] Furthermore, the method for changing the feeding speed according to the liquid surface area ratio in the feeding speed adjustment module includes:

[0023] The feeding rate is set to X kg per hour. The feeding rate is adjusted according to the liquid surface ratio, where the formula relating the adjusted feeding rate to the liquid surface ratio is: Where Y is the changed feeding speed, X is the set feeding speed, and M is the liquid surface area ratio.

[0024] Secondly, the present invention provides a control method for the aforementioned automatic feeding system for granular silicon, comprising:

[0025] Granular silicon is stored in a storage tank and fed through a quartz tube;

[0026] The actual liquid outlet distance is measured by a dual camera pre-set above the single crystal furnace body. When the actual liquid outlet distance is less than the set liquid outlet distance, the system issues an alarm and prompts whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. The liquid outlet distance is the distance from the liquid surface to the guide tube.

[0027] The area ratio of the liquid in the crucible is measured by a rangefinder pre-set above the side of the single crystal furnace. The feeding speed is adjusted according to the area ratio of the liquid. When the actual liquid area ratio is less than the set liquid area ratio, the feeding is stopped and an alarm is triggered.

[0028] The liquid surface temperature is detected by an infrared thermometer pre-set above the single crystal furnace. When the area ratio of the liquid in the crucible is 100% and the liquid surface temperature exceeds the set value, the melting is completed.

[0029] Furthermore, when prompted whether to lower the crucible position, if "Yes" is clicked, the crucible position will be lowered to a distance greater than the set liquid outlet distance; if "No" is clicked, feeding will stop.

[0030] Furthermore, the method for measuring the actual liquid outlet distance includes:

[0031] Measure the reflection L of the guide tube on the liquid surface, and then multiply it by the angle ð of the guide tube to obtain the liquid outlet distance Z = L * tgð.

[0032] Furthermore, the method for measuring the surface area ratio of the liquid in the crucible includes:

[0033] Measure the diameter of the crucible and calculate the total surface area of ​​the liquid based on the crucible diameter;

[0034] The area of ​​the solid on the liquid surface is measured, and the solid area is compared with the total liquid surface area to obtain the solid area ratio. The liquid area ratio is then calculated based on the solid area ratio.

[0035] Furthermore, the method for changing the feeding rate based on the surface area ratio of the liquid includes:

[0036] The feeding rate is set to X kg per hour. The feeding rate is adjusted according to the liquid surface ratio, where the formula relating the adjusted feeding rate to the liquid surface ratio is: Where Y is the changed feeding speed, X is the set feeding speed, and M is the liquid surface area ratio.

[0037] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0038] 1. This invention provides an automatic feeding system for granular silicon and its control method. It uses granular silicon with excellent fluidity. Due to its small size and large contact area with molten silicon, it melts instantly, eliminating the risk of splashing.

[0039] 2. This invention provides an automatic feeding system for granular silicon and its control method. The feeding amount is stable and controllable, and falls within the high-temperature zone closest to the heater, making reasonable use of thermal energy and avoiding accidents caused by sudden rise in liquid level.

[0040] 3. This invention provides an automatic feeding system for granular silicon and its control method. The system can immediately feed and melt the silicon after the crystal rod leaves the liquid surface, without waiting for the crystal rod to be removed, making it more convenient to use. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of conventional RCZ feeding provided in the background art of this invention;

[0042] Figure 2 This is a schematic diagram of the structure of an automatic silicon particle feeding system provided in an embodiment of the present invention;

[0043] Figure 3 This is a flowchart of a control method for an automatic feeding system for granular silicon provided in an embodiment of the present invention.

[0044] In the diagram: 1. Single crystal furnace; 2. Crucible; 3. Flow guide tube; 4. Storage tank. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0048] like Figure 2 As shown in the figure, this embodiment introduces an automatic feeding system for granular silicon, including a single crystal furnace 1 and a crucible 2 disposed within the single crystal furnace 1. The crucible 2 has a liftable structure. The system also includes:

[0049] A flow guide tube 3 is vertically disposed on the top of the inner wall of the single crystal furnace 1. The top end of the flow guide tube 3 is connected to the outside of the single crystal furnace 1, and the bottom end of the flow guide tube 3 extends to the top of the crucible 2.

[0050] Storage tank 4 is located at the top of the single crystal furnace 1, directly opposite the guide tube 3. The bottom of the storage tank 4 is connected to the interior of the single crystal furnace 1 through the guide tube 3 via a quartz tube, and the lower edge of the quartz tube is flush with the lower edge of the guide tube 3.

[0051] The liquid outlet distance adjustment module is used to measure the actual liquid outlet distance through dual cameras pre-set above the single crystal furnace 1. When the actual liquid outlet distance is less than the set liquid outlet distance, the system issues an alarm to prompt whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. The liquid outlet distance is the distance from the liquid surface to the guide tube 3.

[0052] The feeding speed adjustment module is used to measure the area ratio of the liquid in the crucible 2 by a rangefinder set above the side of the single crystal furnace 1, and to change the feeding speed according to the area ratio of the liquid. When the actual liquid area ratio is less than the set liquid area ratio, the feeding is stopped and an alarm is triggered.

[0053] The temperature detection module is used to detect the liquid surface temperature by using an infrared thermometer pre-set above the single crystal furnace 1. When the area ratio of the liquid in the crucible 2 is 100% and the liquid surface temperature exceeds the set value, the melting is completed.

[0054] In a further embodiment, in the liquid outlet distance adjustment module, when prompted whether to lower the crucible position, if "yes" is clicked, the crucible position is lowered to a distance greater than the set liquid outlet distance; if "no" is clicked, feeding is stopped.

[0055] In a further embodiment, the method for measuring the actual liquid outlet distance in the liquid outlet distance adjustment module includes:

[0056] Measure the reflection L of the guide tube on the liquid surface, and then multiply it by the angle ð of the guide tube to obtain the liquid outlet distance Z = L * tgð.

[0057] In a further embodiment, the method for measuring the surface area ratio of the liquid in the crucible in the feeding speed adjustment module includes:

[0058] Measure the diameter of the crucible and calculate the total surface area of ​​the liquid based on the crucible diameter;

[0059] The area of ​​the solid on the liquid surface is measured, and the solid area is compared with the total liquid surface area to obtain the solid area ratio. The liquid area ratio is then calculated based on the solid area ratio.

[0060] In a further embodiment, the method for changing the feeding speed according to the liquid surface area ratio in the feeding speed adjustment module includes:

[0061] The feeding rate is set to X kg per hour. The feeding rate is adjusted according to the liquid surface ratio, where the formula relating the adjusted feeding rate to the liquid surface ratio is: Where Y is the changed feeding speed, X is the set feeding speed, and M is the liquid surface area ratio.

[0062] like Figure 3 As shown, the automatic silicon granulation feeding system provided in this embodiment has the following control principle:

[0063] 1. Crucible Position: As silicon material is added, if the actual liquid outlet distance is less than the set liquid outlet distance, the system will issue an alarm, prompting whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. If "Yes" is clicked, the crucible position will be lowered to a distance greater than the set liquid outlet distance by 10mm. If "No" is clicked, the feeding will stop. After all the silicon material is liquid, the system will display an alarm prompting whether to continue feeding.

[0064] 2. Feeding quantity setting and actual feeding quantity: The feeding weight per hour. The actual feeding quantity will be adjusted proportionally based on the set feeding quantity, according to factors such as liquid outlet distance, liquid area ratio, and liquid surface temperature.

[0065] 3. Liquid surface area ratio setting and actual liquid surface area ratio: There is a rangefinder on the upper side of the furnace body, and the crucible diameter is always 800mm, meaning the total liquid surface area is always 1600mm². 2 Based on the area of ​​the solid on the liquid surface, assume the solid area is 400 mm². 2 The solid area ratio is 25%, and the liquid area ratio is 75%. The feeding rate is set at 50 kg / h, and the feeding rate is adjusted according to the liquid area ratio. The feeding rate as a percentage of the area is Y(feeding rate) = 50. 液体面积比The function is called "feeding". The feeding speed of 50kg can be manually changed. When all components are liquid, the feeding rate follows the set feeding procedure. When both solid and liquid components are present, the feeding is done proportionally. If the actual liquid area ratio is less than the set liquid area ratio, a stop feeding alarm will pop up.

[0066] 4. Liquid Nozzle Distance Setting and Actual Liquid Nozzle Distance: The liquid nozzle distance is the distance from the liquid surface to the guide tube. Currently, the liquid nozzle distance is measured using a dual-camera design typical of single-crystal furnaces. The reflection L of the guide tube on the liquid surface is measured and then multiplied by the guide tube angle ð, i.e., liquid nozzle distance Z = L * tgð. The system has a minimum liquid nozzle distance setting, for example, 10mm. When the actual liquid nozzle distance Z is less than 10mm, the system issues an alarm, prompting whether to lower the crucible position to ensure that the actual liquid nozzle distance is greater than the set liquid nozzle distance. If the actual liquid nozzle distance is greater than the set liquid nozzle distance, the system continues to operate according to the set process.

[0067] 5. Liquid Surface Temperature: An infrared thermometer is installed on the furnace body to continuously monitor the liquid surface temperature. When the actual liquid surface area is 100%, meaning there is no solid, and the liquid surface temperature exceeds the set value of 1430℃ (the melting point of silicon is 1420℃), a pop-up message will appear indicating that the melting process is complete and whether to enter a stable temperature state. The liquid surface temperature set value can be manually changed. Example 2

[0068] like Figure 3 As shown, this embodiment provides a control method for the automatic feeding system for granular silicon according to Embodiment 1, including:

[0069] Granular silicon is stored in a storage tank and fed through a quartz tube;

[0070] The actual liquid outlet distance is measured by a dual camera pre-set above the single crystal furnace body. When the actual liquid outlet distance is less than the set liquid outlet distance, the system issues an alarm and prompts whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. The liquid outlet distance is the distance from the liquid surface to the guide tube.

[0071] The area ratio of the liquid in the crucible is measured by a rangefinder pre-set above the side of the single crystal furnace. The feeding speed is adjusted according to the area ratio of the liquid. When the actual liquid area ratio is less than the set liquid area ratio, the feeding is stopped and an alarm is triggered.

[0072] The liquid surface temperature is detected by an infrared thermometer pre-set above the single crystal furnace. When the area ratio of the liquid in the crucible is 100% and the liquid surface temperature exceeds the set value, the melting is completed.

[0073] In a further embodiment, when prompted whether to lower the crucible position, if "Yes" is clicked, the crucible position is lowered to a distance greater than the set liquid outlet distance; if "No" is clicked, feeding is stopped.

[0074] In a further embodiment, the method for measuring the actual liquid outlet distance includes:

[0075] Measure the reflection L of the guide tube on the liquid surface, and then multiply it by the angle ð of the guide tube to obtain the liquid outlet distance Z = L * tgð.

[0076] In a further embodiment, the method for measuring the surface area ratio of the liquid in the crucible includes:

[0077] Measure the diameter of the crucible and calculate the total surface area of ​​the liquid based on the crucible diameter;

[0078] The area of ​​the solid on the liquid surface is measured, and the solid area is compared with the total liquid surface area to obtain the solid area ratio. The liquid area ratio is then calculated based on the solid area ratio.

[0079] In a further embodiment, the method of changing the feeding rate according to the surface ratio of the liquid includes:

[0080] The feeding rate is set to X kg per hour. The feeding rate is adjusted according to the liquid surface ratio, where the formula relating the adjusted feeding rate to the liquid surface ratio is: Where Y is the changed feeding speed, X is the set feeding speed, and M is the liquid surface area ratio.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An automatic feeding system for granular silicon, comprising a single crystal furnace and a crucible disposed within the single crystal furnace, wherein the crucible has a liftable structure, characterized in that, The system also includes: A flow guide tube is vertically disposed on the top of the inner wall of the single crystal furnace. The top end of the flow guide tube is connected to the outside of the single crystal furnace, and the bottom end of the flow guide tube extends to the top of the crucible. A storage tank is located at the top of the single crystal furnace, directly opposite the guide tube. The bottom of the storage tank is connected to the interior of the single crystal furnace through a quartz tube passing through the guide tube, and the lower edge of the quartz tube is flush with the lower edge of the guide tube. The liquid outlet distance adjustment module is used to measure the actual liquid outlet distance through dual cameras pre-set above the single crystal furnace body. When the actual liquid outlet distance is less than the set liquid outlet distance, the system issues an alarm to prompt whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. The liquid outlet distance is the distance from the liquid surface to the guide tube. The feeding speed adjustment module is used to measure the area ratio of the liquid in the crucible by a rangefinder set above the side of the single crystal furnace body, and adjust the feeding speed according to the area ratio of the liquid. When the actual liquid area ratio is less than the set liquid area ratio, the feeding is stopped and an alarm is triggered. The method for measuring the surface area ratio of the liquid inside the crucible in the feeding speed adjustment module includes: Measure the diameter of the crucible and calculate the total surface area of ​​the liquid based on the crucible diameter; The area of ​​the solid on the liquid surface is measured, and the solid area is compared with the total liquid surface area to obtain the solid area ratio. The liquid area ratio is then calculated based on the solid area ratio. The method for changing the feeding speed according to the liquid surface area ratio in the feeding speed adjustment module includes: The feeding rate is set to X kg per hour. The feeding rate is adjusted according to the liquid surface ratio, where the formula relating the adjusted feeding rate to the liquid surface ratio is: Where Y is the changed feeding speed, X is the set feeding speed, and M is the liquid surface area ratio; The temperature detection module is used to detect the liquid surface temperature by using an infrared thermometer pre-set above the single crystal furnace. When the area ratio of the liquid in the crucible is 100% and the liquid surface temperature exceeds the set value, the melting is completed.

2. The automatic feeding system for granular silicon according to claim 1, characterized in that, In the liquid outlet distance adjustment module, when prompted whether to lower the crucible position, if "Yes" is clicked, the crucible position will be lowered to a distance greater than the set liquid outlet distance; if "No" is clicked, feeding will stop.

3. The automatic feeding system for granular silicon according to claim 1, characterized in that, The method for measuring the actual liquid outlet distance in the liquid outlet distance adjustment module includes: Measure the reflection L of the guide tube on the liquid surface, and then multiply it by the angle ð of the guide tube to obtain the liquid outlet distance Z = L * tgð.

4. A control method for the automatic feeding system for granular silicon according to claim 1, characterized in that, include: Granular silicon is stored in a storage tank and fed through a quartz tube; The actual liquid outlet distance is measured by a dual camera pre-set above the single crystal furnace body. When the actual liquid outlet distance is less than the set liquid outlet distance, the system issues an alarm and prompts whether to lower the crucible position to ensure that the actual liquid outlet distance is greater than the set liquid outlet distance. The liquid outlet distance is the distance from the liquid surface to the guide tube. The surface area ratio of the liquid in the crucible is measured by a rangefinder pre-set above the side of the single crystal furnace. The feeding speed is adjusted according to the surface area ratio. When the actual liquid surface area ratio is less than the set liquid surface area ratio, feeding is stopped and an alarm is triggered. Methods for measuring the surface area ratio of the liquid inside a crucible include: Measure the diameter of the crucible and calculate the total surface area of ​​the liquid based on the crucible diameter; The area of ​​the solid on the liquid surface is measured, and the solid area is compared with the total liquid surface area to obtain the solid area ratio. The liquid area ratio is then calculated based on the solid area ratio. Methods for changing the feeding rate based on the surface area ratio of the liquid include: The feeding rate is set to X kg per hour. The feeding rate is adjusted according to the liquid surface ratio, where the formula relating the adjusted feeding rate to the liquid surface ratio is: Where Y is the changed feeding speed, X is the set feeding speed, and M is the liquid surface area ratio; The liquid surface temperature is detected by an infrared thermometer pre-set above the single crystal furnace. When the area ratio of the liquid in the crucible is 100% and the liquid surface temperature exceeds the set value, the melting is completed.

5. The control method for the automatic feeding system for granular silicon according to claim 4, characterized in that, When prompted whether to lower the crucible position, if "Yes" is clicked, the crucible position will be lowered to a distance greater than the set liquid outlet distance; if "No" is clicked, feeding will stop.

6. The control method for the automatic feeding system for granular silicon according to claim 4, characterized in that, The method for measuring the actual liquid outlet distance includes: Measure the reflection L of the guide tube on the liquid surface, and then multiply it by the angle ð of the guide tube to obtain the liquid outlet distance Z = L * tgð.

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