Online self-cleaning device for evacuated pipes

Abstract

The present invention provides an online self-cleaning device for an evacuation pipe. The self-cleaning device is disposed on a vacuum evacuation pipe of a silicon single crystal furnace, and the self-cleaning device is located near the inlet of the vacuum evacuation pipe. The vacuum evacuation pipe is provided with an entry hole. The self-cleaning device includes a stirring cleaning device that penetrates into the vacuum evacuation pipe through the entry hole, and a driving mechanism that is disposed outside the vacuum evacuation pipe and drives the stirring cleaning device. The present invention can, when the silicon single crystal furnace is operating normally, drive a reduction motor to rotate the stirring cleaning device, cutting and stirring impurities or volatiles attached to the inner wall of the inlet section of the vacuum evacuation pipe, causing the impurities or volatiles to separate from the inner wall of the vacuum evacuation pipe. Under the action of the negative pressure of the vacuum pump group, the impurities or volatiles flow toward a filter and the vacuum pump group, away from the vacuum furnace chamber, thereby achieving an online self-cleaning effect.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic-grade or photovoltaic-grade silicon single crystal growth, in particular to an online self-cleaning device for evacuating pipes during normal operation of a silicon single crystal furnace. Background Art

[0002] Silicon single crystals are the fundamental material for the photovoltaic cell and semiconductor industries. Over 90% of photovoltaic cells and over 95% of semiconductor devices utilize silicon-based substrates. Driven by factors such as production efficiency and cost reduction for photovoltaic cells and semiconductor devices, the current primary development direction is to extend the operating time of each furnace and increase the yield of silicon single crystals per furnace, driven by improvements in the operational stability of silicon single crystal furnaces' vacuum chambers, thermal fields, motion devices, vacuum pumps, and their control systems, as well as advances in quartz crucible manufacturing technology and the extension of quartz crucibles' safe high-temperature operation time.

[0003] The longer each furnace runs, the more polysilicon material is loaded in the furnace, the more volatiles are produced, and the more impurities or volatiles are deposited in the evacuation pipe. If they are not cleaned online in time, at the very least, the flow area of ​​the evacuation pipe will become smaller, the flow capacity will be reduced, the efficiency of the vacuum pump group in evacuating the vacuum furnace chamber will be reduced, and the pressure in the vacuum furnace chamber will gradually increase. Impurities or volatiles cannot be discharged, and they will float in the vacuum furnace chamber, fall into the crucible, float on the surface of the silicon melt, or be deposited on the silicon crystal rod, the guide tube or the inner surface of the furnace cover, accumulate into pieces or blocks and fall into the crucible, causing the crystal to break, unable to continue growing, and other faults; at worst, the evacuation pipe will be blocked, the pressure in the vacuum furnace chamber will rise uncontrollably, and safety accidents for equipment and personnel will occur.

[0004] Therefore, online and timely cleaning of impurities and volatiles at the inlet section of the evacuation pipeline is the most important issue faced in extending the operating time of each furnace, increasing the output of each silicon single crystal furnace, and maintaining the stability of silicon single crystal quality. Summary of the Invention

[0005] In response to the above technical problems, an online self-cleaning device for vacuum evacuation pipes is provided. The present invention primarily utilizes an online impurity or volatile matter stirring and cleaning device installed at the inlet of the vacuum evacuation pipe of a silicon single crystal furnace. This device allows impurities or volatile matter adhering to the inner wall of the inlet section of the vacuum evacuation pipe to separate from the inner wall of the evacuation pipe during normal operation of the silicon single crystal furnace. The impurities or volatile matter are then removed from the inner wall of the evacuation pipe by the negative pressure of the vacuum pump assembly, thereby cleaning the chamber.

[0006] The technical means adopted in the present invention are as follows:

[0007] An online self-cleaning device for an evacuation pipe, the self-cleaning device being arranged on a vacuum evacuation pipe of a silicon single crystal furnace and being close to the inlet of the vacuum evacuation pipe, the vacuum evacuation pipe being provided with an entry hole; and the vacuum evacuation pipe being provided with a cold water interlayer near its inlet;

[0008] The self-cleaning device includes a stirring cleaning device that penetrates into the vacuum evacuation pipe through the penetration hole and a driving mechanism that is arranged outside the vacuum evacuation pipe and drives the stirring cleaning device to work;

[0009] The stirring cleaning device includes a rotating shaft, and a stirring mechanism is fixed at one end of the rotating shaft in the vacuum evacuation pipe, and the stirring mechanism is close to the inlet of the vacuum evacuation pipe;

[0010] The driving mechanism includes a magnetic fluid sealing device for sealing the penetration hole and a reduction motor for driving the rotating shaft to rotate. One end of the rotating shaft outside the vacuum evacuation pipe is connected to the output end of the reduction motor through the magnetic fluid sealing device.

[0011] The stirring mechanism includes a plurality of stirring bodies evenly distributed around the axis of the rotating shaft.

[0012] The stirring body includes a stirring arm and multiple connecting arms connecting the stirring arm and the rotating shaft. The distance between the stirring arm and the inner wall of the vacuum evacuation pipe gradually increases from the end of the stirring arm close to the entrance of the vacuum evacuation pipe to the end of the stirring arm away from the entrance of the vacuum evacuation pipe.

[0013] A connecting pipe matching the penetration hole is fixed at the penetration hole, and the rotating shaft enters the vacuum evacuation pipe through the connecting pipe and the penetration hole.

[0014] An isolation disc is installed in the connecting pipe and fixedly connected to the rotating shaft. The isolation disc and the rotating shaft are arranged coaxially to prevent impurities or volatiles from falling onto the magnetic fluid sealing device and overheating the magnetic fluid. It also prevents excessive impurities or volatiles from being deposited around coupling I and rubbing against coupling I, increasing rotational damping.

[0015] A temperature sensor is installed on the connecting pipe to detect the temperature value and the heating condition of the pipe wall near the magnetic fluid in real time to avoid overheating of the magnetic fluid.

[0016] The end of the connecting pipe away from the penetration hole is fixedly connected to the connecting flange II fixed to one end of the magnetic fluid device through the connecting flange I, and the connecting flange II is fixedly connected to the bracket, and a sealing ring is provided between the connecting flange I and the connecting flange II.

[0017] One end of the rotating shaft outside the vacuum evacuation pipe is connected to one end of the magnetic fluid sealing device through a coupling I arranged in the connecting pipe, and the other end of the magnetic fluid sealing device is connected to the output end of the reduction motor through a coupling II arranged in the bracket, and the reduction motor is fixedly connected to the bracket.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The online self-cleaning device for the evacuation pipe can drive the reduction motor to drive the stirring body to rotate when the silicon single crystal furnace is operating normally, cutting and stirring impurities or volatiles attached to the inner wall of the inlet section of the vacuum evacuation pipe, so that the impurities or volatiles are separated from the inner wall of the vacuum evacuation pipe and are affected by the negative pressure of the vacuum pump group. The impurities or volatiles flow toward the filter and the vacuum pump group, away from the vacuum furnace chamber, thereby playing the role of online self-cleaning.

[0020] Based on the above reasons, the present invention can be widely promoted in the fields of electronic-grade or photovoltaic-grade silicon single crystal manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 This is a structural schematic diagram of the online self-cleaning device for evacuated pipelines in use according to a specific embodiment of the present invention.

[0023] Figure 2 for Figure 1 main view.

[0024] Figure 3 for Figure 2 Middle AA section view.

[0025] Figure 4 This is a structural schematic diagram of the online self-cleaning device for evacuated pipelines in a specific embodiment of the present invention (excluding the stirring mechanism).

[0026] Figure 5 Schematic diagram of the stirring mechanism structure in a specific embodiment of the present invention.

[0027] Figure 6 It is a top view of the stirring mechanism in a specific embodiment of the present invention.

[0028] In the picture:

[0029] 1. Self-cleaning device; 11. Insertion hole; 12. Rotating shaft; 13. Magnetic fluid sealing device; 14. Reducer motor; 15. Connecting pipe; 16. Isolation disk; 17. Temperature sensor;

[0030] 2. Silicon single crystal furnace; 21. Furnace chassis; 22. Cylindrical furnace chamber; 23. Crucible axis hole; 24. Electrode opening; 25. Electrode; 26. Cooling water temperature sensor;

[0031] 3. Vacuum evacuation pipeline; 31. Inlet; 32. Water-cooled interlayer; 33. Main pipeline; 34. Explosion-proof safety valve I; 35. Electric vacuum ball valve; 36. Explosion-proof safety valve II; 37. Vacuum leak detection reserved port; 38. Oxidation device reserved port;

[0032] 4. stirring body; 41. stirring arm; 42. connecting arm;

[0033] 5. Connecting flange I; 51. Connecting flange II; 52. Bracket; 53. Sealing ring; 54. Coupling I; 55. Coupling II. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0038] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0039] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0040] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0041] like Figure 1-6As shown, an online self-cleaning device for an evacuation pipe is provided. The self-cleaning device 1 is provided on a vacuum evacuation pipe 3 of a silicon single crystal furnace 2, and the self-cleaning device 1 is close to an inlet 31 of the vacuum evacuation pipe 3. An entry hole 11 is provided on the vacuum evacuation pipe 3.

[0042] The vacuum evacuation pipe 3 is arranged at the bottom (or side) of the vacuum furnace chamber of the silicon single crystal furnace 2. In this embodiment, it is the bottom. The vacuum furnace chamber of the electronic grade or photovoltaic grade silicon single crystal furnace 2 includes a furnace bottom plate 21, a cylindrical furnace chamber 22, a furnace cover, a stop valve (rotary vane valve or flap valve) and an auxiliary furnace chamber (the furnace cover, stop valve and auxiliary furnace chamber are omitted in the figure); multiple vacuum evacuation pipes 3 (two in this embodiment) are respectively connected to the furnace bottom plate 21 at the bottom of the vacuum furnace chamber. The vacuum evacuation pipe 3 is a vertical section at the inlet 31, and then extends obliquely to the rear. A water-cooled interlayer 32 is provided outside the vertical section, and an oxygen cooling layer is provided on the side wall of the vertical section. A reserved port 38 is provided for the chemical device, and then the two vacuum evacuation pipes are combined into a main pipe 33 through a tee pipe; thereafter, the main pipe 33 is provided with an explosion-proof safety valve I 34, an electric vacuum ball valve 35 (or an electric vacuum butterfly valve + a pneumatic vacuum ball valve), an explosion-proof safety valve II 36, and a reserved port 37 for vacuum leak detection in sequence. The part of the main pipe 33 between the explosion-proof safety valve II 36 and the electric vacuum ball valve 35 is connected to the filter and the vacuum pump group through a pipeline (the filter and the vacuum pump group are omitted in the figure), the explosion-proof safety valve I 34 is vertically arranged, and the explosion-proof safety valve II 36 is inclined at 45°.

[0043] A crucible axis hole 23 is provided at the center of the furnace bottom plate 21; paired electrode reserved openings 24 and paired electrodes 25 are provided around the crucible axis hole 23; a cooling water temperature sensor 26 is provided at the bottom of the furnace bottom plate 21, near the inlet 31 of the vacuum evacuation pipe 3 and the electrode 25;.

[0044] The self-cleaning device 1 includes a stirring cleaning device that penetrates into the vacuum evacuation pipe 3 through the penetration hole 11 and a driving mechanism that is arranged outside the vacuum evacuation pipe 3 and drives the stirring cleaning device to work;

[0045] The stirring cleaning device includes a rotating shaft 12, and a stirring mechanism is fixed at one end of the rotating shaft 12 in the vacuum evacuation pipe 3, and the stirring mechanism is close to the entrance 31 of the vacuum evacuation pipe 3; in this embodiment, the penetration hole 11 is arranged at the bend of the vacuum evacuation pipe 3, so the rotating shaft 12 is arranged vertically.

[0046] The driving mechanism includes a magnetic fluid sealing device 13 for sealing the penetration hole and a reduction motor 14 for driving the rotating shaft 12 to rotate. One end of the rotating shaft 12 outside the vacuum evacuation pipe 3 is connected to the output end of the reduction motor 14 through the magnetic fluid sealing device 13.

[0047] The stirring mechanism includes a plurality of stirring bodies 4 evenly distributed around the axis of the rotating shaft, and in this embodiment, there are three stirring bodies 4.

[0048] The stirring body 4 includes a stirring arm 41 and multiple connecting arms 42 (three in this embodiment) connecting the stirring arm 41 and the rotating shaft 12. The distance between the stirring arm 41 and the inner wall of the vacuum evacuation pipe 3 gradually increases from the end of the stirring arm 41 close to the entrance 31 of the vacuum evacuation pipe 3 to the end of the stirring arm 41 away from the entrance 31 of the vacuum evacuation pipe 3.

[0049] A connecting pipe 15 matching the penetration hole 11 is fixed at the penetration hole 11 , and the rotating shaft 12 enters the vacuum evacuation pipe 3 through the connecting pipe 15 and the penetration hole 11 .

[0050] An isolation disk 16 is installed in the connecting pipe 15 and is fixedly connected to the rotating shaft 12. The isolation disk 16 is coaxially arranged with the rotating shaft 12 to prevent impurities or volatiles from falling onto the magnetic fluid sealing device 13 and causing the magnetic fluid to overheat.

[0051] The connecting pipe 15 is provided with a temperature sensor 17 for detecting the temperature value and detecting the heating condition of the pipe wall near the magnetic fluid in real time to prevent the magnetic fluid from overheating.

[0052] The end of the connecting pipe 15 away from the penetration hole 11 is fixedly connected to the connecting flange II 51 fixed to one end of the magnetic fluid device 13 through the connecting flange I5, and the connecting flange II 51 is fixedly connected to the bracket 52. A sealing ring 53 is provided between the connecting flange I5 and the connecting flange II 51.

[0053] One end of the rotating shaft 12 outside the vacuum evacuation pipe 3 is connected to one end of the magnetic fluid sealing device 13 via a coupling I 54 disposed in the connecting pipe 15. The other end of the magnetic fluid sealing device 13 is connected to the output end of the reduction motor 14 via a coupling II 55 disposed in the bracket 52. The reduction motor 14 is fixedly connected to the bracket 52. The connecting rods at both ends of the magnetic fluid sealing device 13 can rotate relative to its housing, thereby transmitting the rotation of the reduction motor 14 and simultaneously providing a seal to prevent vacuum leakage.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An online self-cleaning device for evacuated pipes, characterized in that: The self-cleaning device is arranged on the vacuum evacuation pipe of the silicon single crystal furnace, and the self-cleaning device is close to the inlet of the vacuum evacuation pipe, and the vacuum evacuation pipe is provided with an entry hole; the vacuum evacuation pipe has a cold water interlayer near its inlet; The self-cleaning device includes a stirring cleaning device that penetrates into the vacuum evacuation pipe through the penetration hole and a driving mechanism that is arranged outside the vacuum evacuation pipe and drives the stirring cleaning device to work; The stirring cleaning device includes a rotating shaft, and a stirring mechanism is fixed at one end of the rotating shaft in the vacuum evacuation pipe, and the stirring mechanism is close to the inlet of the vacuum evacuation pipe; The stirring mechanism includes a plurality of stirring bodies evenly distributed around the axis of the rotating shaft; The stirring body includes a stirring arm and a plurality of connecting arms connecting the stirring arm and the rotating shaft, wherein the distance between the stirring arm and the inner wall of the vacuum evacuation pipe gradually increases from an end of the stirring arm close to the entrance of the vacuum evacuation pipe to an end of the stirring arm away from the entrance of the vacuum evacuation pipe; The driving mechanism includes a magnetic fluid sealing device for sealing the penetration hole and a reduction motor for driving the rotating shaft to rotate, and one end of the rotating shaft outside the vacuum evacuation pipe is connected to the output end of the reduction motor through the magnetic fluid sealing device; A connecting pipe matching the penetration hole is fixed at the penetration hole, and the rotating shaft enters the vacuum evacuation pipe through the connecting pipe and the penetration hole; An isolation disk is installed in the connecting pipe, and the isolation disk is fixedly connected to the rotating shaft, and the isolation disk is coaxially arranged with the rotating shaft; The end of the connecting pipe away from the penetration hole is fixedly connected to the connecting flange II fixed to one end of the magnetic fluid sealing device through the connecting flange I, and the connecting flange II is fixedly connected to the bracket, and a sealing ring is provided between the connecting flange I and the connecting flange II; One end of the rotating shaft outside the vacuum evacuation pipe is connected to one end of the magnetic fluid sealing device through a coupling I arranged in the connecting pipe, and the other end of the magnetic fluid sealing device is connected to the output end of the reduction motor through a coupling II arranged in the bracket, and the reduction motor is fixedly connected to the bracket.

2. The online self-cleaning device for evacuated pipes according to claim 1, characterized in that: A temperature sensor is installed on the connecting pipe.

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