Vacuum dust removal equipment for monocrystalline silicon crystal pulling furnace

Abstract

The invention relates to the technical field of monocrystalline silicon, in particular to monocrystalline silicon crystal pulling furnace vacuum dust removal equipment which comprises a filter and a dust collection system. The two filter screens are arranged in the filter, the ultrasonic transducers are adopted in the two filter screens, dust on the filter screens can be shaken off, and therefore the filtering stability is guaranteed, meanwhile, through pipeline arrangement, the two filter screens can be used in multiple modes such as alternate use, combined use and independent use, and the filter efficiency is improved. And the service life and the stability are effectively guaranteed while using is more convenient and faster, in addition, dust can be stably and continuously collected through the dust collecting system, and continuous and stable system operation is guaranteed. The dust removal equipment runs continuously and stably, on one hand, the dust removal effect and stability are guaranteed, on the other hand, the service life of the equipment is guaranteed, and continuous, stable and reliable use in actual production is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of single crystal silicon, and in particular to vacuum dust removal equipment for a single crystal silicon pulling furnace. Background Art

[0002] Crystal pulling is a process in the production of single crystal silicon. It is carried out in a crystal pulling furnace. Crystal pulling needs to be carried out in an inert gas atmosphere. At the same time, since dust, such as SiO, is generated in the process of crystal pulling, excessive dust will affect the quality of the product. Therefore, in actual production, the dust generated in the system needs to be filtered out.

[0003] Most of the existing dust filtering equipment is of bag type. Although bag filters can meet basic usage requirements, they still have many inconveniences in practice. First of all, for the crystal pulling process, the production time of a single batch is generally about 7 days. During the production process, the inert gas is introduced and filtered continuously. Due to the small particle size of the dust generated in the crystal pulling process, it is difficult for bag filters to ensure stability of use during long-term use. Problems such as increased pressure and low filtration efficiency often occur due to blockage of the cross-woven mesh, which not only affects the stability of production, but also brings huge energy consumption. In addition, the long-term high-load operation of the equipment not only affects the service life of the equipment but also has high safety hazards.

[0004] Therefore, a dust removal device that can stably and efficiently filter the inert gas in the crystal pulling furnace during the single crystal silicon production process is a technical problem that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a vacuum dust removal device for a single crystal silicon pulling furnace to solve the problem that the filtration resistance of the existing dust removal equipment will continue to increase with the extension of the operating time, thereby affecting the stability of use.

[0006] To achieve the above-mentioned object, the present invention adopts the following technical scheme: a vacuum dust removal device for a single crystal silicon pulling furnace, comprising a filter;

[0007] The filter is horizontal, one end of the filter is provided with an air inlet, the other end of the filter is provided with an air outlet, the air inlet is connected to the air inlet pipe, the air inlet pipe is connected to the crystal pulling furnace, the air outlet is connected to the air outlet pipe, and the air outlet pipe is connected to the vacuum pump;

[0008] The filter is provided with two filter screens, namely the first filter screen and the second filter screen, the air intake pipe includes a main air intake pipe, the main air intake pipe is divided into two pipes, namely the first air intake pipe and the second air intake pipe, the first air intake pipe is connected to the air inlet; the filter housing between the first filter screen and the second filter screen is provided with a first connecting port and a second connecting port, the second air intake pipe is connected to the first connecting port; the filter housing behind the second filter screen is provided with a third connecting port, the second connecting port and the third connecting port are connected through a connecting pipe, and the third connecting port is connected to the air distribution nozzle inside the filter;

[0009] The first air intake pipe is provided with a first control valve, the second air intake pipe is provided with a second control valve, and the connecting pipe is provided with a third control valve;

[0010] The first filter and the second filter have the same structure, wherein the second filter comprises an ultrasonic filter frame, a screen is mounted on the ultrasonic filter frame, and support bars are arranged on both sides of the screen; an ultrasonic transducer is detachably mounted on the ultrasonic filter frame, and the ultrasonic transducer is located behind the support bar on the rear side of the screen;

[0011] The first filter screen and the second filter screen have multiple working modes, including alternating working, joint working and individual working.

[0012] Furthermore, the air distribution nozzle is detachably connected to the third connecting port, the air distribution nozzle is fan-shaped, and the air flow forms an air curtain behind the second filter screen after passing through the air distribution nozzle.

[0013] Furthermore, it also includes a dust collection system, which includes two dust collection troughs, namely a first dust collection trough and a second dust collection trough. The first dust collection trough is located in front of the first filter screen, and the second dust collection trough is located in front of the second filter screen.

[0014] Furthermore, the first dust collecting trough and the second dust collecting trough are connected to the Y-shaped tube below, a first manual valve is arranged on the branch tube on the left side of the Y-shaped tube, a second manual valve is arranged on the branch tube on the right side of the Y-shaped tube, and the lower end of the Y-shaped tube is detachably connected to the dust collecting tank.

[0015] Furthermore, when the first filter screen and the second filter screen work alternately, the aperture of the first filter screen is kept consistent with the aperture of the second filter screen; if the first filter screen is working, the second control valve is closed, the third control valve is opened, the first manual valve is opened and the second manual valve is closed; if the second filter screen is working, the second control valve is opened, the first control valve is closed, the first manual valve and the third control valve are closed and the second manual valve is opened.

[0016] Furthermore, when the first filter screen and the second filter screen work together, the aperture of the first filter screen is larger than the aperture of the second filter screen. At this time, the second control valve, the third control valve, the first manual valve and the second manual valve are closed at the same time; the first manual valve and the second manual valve are opened and closed alternately at a certain interval.

[0017] Furthermore, a third manual valve is provided on the vertical tube of the Y-shaped tube, the dust collecting tank is detachably installed below the vertical tube of the Y-shaped tube, an air pressure balance tube is provided on one side of the dust collecting tank, and an air pressure balance valve is provided on the air pressure balance tube.

[0018] Furthermore, the vertical tube of the Y-tube is provided with a connecting port above the third manual valve, a Venturi tube is provided on the main air intake pipe, the connecting port is connected to the throat inside the Venturi through the connecting pipe, a fourth control valve is provided on the connecting pipe, and a dust cover is provided at the inlet of the connecting port.

[0019] Beneficial effects of the present invention:

[0020] 1. In the present invention, the filter screen adopts an ultrasonic transducer, so that the dust on the screen can be continuously shaken off, which can effectively ensure the filtering effect of the filter screen and also play a positive role in the stability of the equipment;

[0021] 2. In the present invention, the filter is horizontal, which can facilitate the shaking and collection of dust on the one hand, and on the other hand, it is also convenient to use two filter screens to achieve the alternating use of the filter screens;

[0022] 3. In the present invention, two filter screens are provided and multiple usage modes can be adopted, thus ensuring the stability, effectiveness and reliability of use;

[0023] 4. In the method of the present invention, the dust can be stably collected through the dust collection system. The dust in the dust collecting trough and the Y-shaped tube will not rise, and the collection is more stable and efficient. At the same time, it is also convenient for timely replacement and cleaning of the dust collecting tank, and it is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the main cross-section of the overall structure of the present invention;

[0025] Figure 2 The present invention Figure 1 A cross-sectional view of the middle AA plane (schematic diagram of the second filter structure);

[0026] Figure 3 It is a schematic diagram of the structure of the air distribution nozzle of the present invention.

[0027] The names corresponding to the marks in the figure are:

[0028] 1. Main air intake pipe; 11. First air intake pipe; 111. First control valve; 12. Second air intake pipe; 121. Second control valve; 13. Venturi tube; 2. Filter; 21. Air inlet; 22. Air outlet; 23. First filter screen; 24. Second filter screen; 241. Ultrasonic filter screen frame; 242. Screen; 243. Support bar; 244. Ultrasonic transducer; 25. First connecting port; 26. Second connecting port; 27. Third Connecting port; 28, connecting pipe; 281, third control valve; 29, air distribution nozzle; 3, dust collection system; 31, first dust collecting tank; 32, second dust collecting tank; 33, Y-type tube; 331, connecting port; 332, dust cover; 333, first manual valve; 334, second manual valve; 34, third manual valve; 35, dust collecting tank; 351, air pressure balance pipe; 352, air pressure balance valve; 36, connecting pipe; 361, fourth control valve. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] Embodiments of the present invention:

[0031] like Figure 1-3 As shown, a filter 2 is provided in the dust removal equipment of this embodiment. The filter 2 is horizontal, and an air inlet 21 is provided at one end of the filter 2, and an air outlet 22 is provided at the other end. The air inlet 21 is connected to an air inlet pipe, and the air outlet 22 is connected to an air outlet pipe. The air inlet pipe is connected to a single crystal silicon pulling furnace, and the air outlet pipe is connected to a vacuum pump.

[0032] In this embodiment, the air intake pipe includes a main air intake pipe 1, which is connected to the single crystal silicon pulling furnace. The main air intake pipe 1 is divided into two pipes through a three-way pipe, namely a first air intake pipe 11 and a second air intake pipe 12. The first air intake pipe 11 is connected to the air inlet 21, and a first control valve 111 is arranged on the first air intake pipe 11, and a second control valve 121 is arranged on the second air intake pipe 12.

[0033] In this embodiment, two filter screens are arranged inside the filter 2, namely a first filter screen 23 at the front end and a second filter screen 24 at the rear end. A first connecting port 25 and a second connecting port 26 are opened on the filter 2 shell between the first filter screen 23 and the second filter screen 24, wherein the first connecting port 25 is connected to the second air intake pipe 12; a third connecting port 27 is arranged on the filter 2 shell behind the second filter screen 24, the second connecting port 26 and the third connecting port 27 are connected through a connecting pipe 28, and a third control valve 281 is arranged on the connecting pipe 28. Inside the filter 2, the third connecting port 27 is detachably connected to the air distribution nozzle 29, wherein the air distribution nozzle 29 is fan-shaped, so that the wind blown out of the third connecting port 27 forms a wind curtain behind the second filter screen 24.

[0034] In this embodiment, the structure of the first filter 23 is consistent with that of the second filter 24. Taking the second filter 24 as an example, the first filter 23 includes an ultrasonic filter frame 241, which is connected to the filter 2 housing through a flange. A screen 242 is installed through the ultrasonic filter frame 241, and support bars 243 are respectively provided on both sides of the screen 242. In addition, an ultrasonic transducer 244 is detachably installed through the ultrasonic filter frame 241, and the ultrasonic transducer 244 is located behind the support bar 243 of the screen 242.

[0035] In this embodiment, the dust removal device of the present invention also includes a dust collecting system 3, wherein the dust collecting system 3 includes two dust collecting grooves, namely a first dust collecting groove 31 and a second dust collecting groove 32, the first dust collecting groove 31 is located at the front end of the first filter 23, and the second dust collecting groove 32 is located at the front end of the second filter 24, and the first dust collecting groove 31 and the second dust collecting groove 32 are detachably connected to the dust collecting tank 35 through a Y-shaped tube 33, wherein a first manual valve 333 is arranged on the branch pipe on the left side of the Y-shaped tube 33, a second manual valve 334 is arranged on the branch pipe on the right side of the Y-shaped tube 33, and a third manual valve 34 is arranged on the vertical tube below the Y-shaped tube 33, and an air pressure balance pipe 351 is also arranged on the dust collecting tank 35, and an air pressure balance valve 352 is installed on the air pressure balance pipe 351.

[0036] In other embodiments of the present invention, vacuum pressure gauges are respectively installed on the first filter 23 and the filter 2 housing between the first filter 23 and the second filter 24. The pressure in the filter 2 is monitored by the vacuum pressure gauge, and timely adjustments are made when equipment fails to operate, thereby ensuring production safety.

[0037] In other embodiments of the present invention, a connecting port 331 is further provided at the vertical portion of the Y-shaped tube 33, a Venturi tube 13 is provided on the main air intake pipe 1, the connecting port 331 is connected to the throat of the Venturi tube 13 through a connecting tube 36, and a fourth control valve 361 is provided on the connecting tube 36, and a dust cover 332 with an opening at the bottom is provided at the entrance of the connecting port 331 inside the Y-shaped tube 33.

[0038] The principle of the present invention is:

[0039] The present invention can filter the inert gas (argon, etc.) protective atmosphere in the crystal pulling furnace during use, thereby timely removing impurities (SiO, etc.) generated during the crystal pulling process, thereby ensuring product quality.

[0040] During the implementation of the present invention, there may be a variety of working modes. First, there is a working mode in which the first filter screen 23 and the second filter screen 24 are used alternately. In this mode, the aperture sizes of the two screens remain consistent. The alternating use of this mode during the process is mainly intended to avoid long-term operation of a single ultrasonic transducer 244 (ultrasonic power is 100W), which can effectively protect the service life of the ultrasonic transducer 244.

[0041] During the above-mentioned alternating use, the first manual valve 333 is kept open, and the airflow enters the filter 2 from the first air inlet pipe 11 by opening the first control valve 111, closing the second control valve 121 and closing the second manual valve 334, and is filtered through the first filter screen 23. At this time, the third control valve 281 is opened, and the filtered airflow passes through the connecting pipe 28 and then is discharged from the air outlet 22. In this process, on the one hand, there is a large resistance for the gas to pass through the second filter screen 24, and on the other hand, the air curtain formed by the air distribution nozzle 29 (the width of the air distribution nozzle 29 is relatively large) is formed. The second filter screen 24 is narrow, generally between 0.5 and 2 cm), and the filtered gas basically does not flow through the second filter screen 24. At this time, the second filter screen 24 is basically in a non-working state; after the first filter screen 23 has worked for a period of time, the second filter screen 24 can be switched to work. At this time, the first control valve 111, the third control valve 281 and the first manual valve 333 are closed, the second control valve 121 is opened, and then the second manual valve 334 is opened. In actual production, the switching frequency of the first filter screen 23 and the second filter screen 24 can be controlled at 4 to 8 hours per time.

[0042] The second working mode is a mode in which the first filter 23 and the second filter 24 are combined for filtering. In this mode, the first control valve 111 is opened and the second control valve 121 and the third control valve 281 are closed. This mode is a reasonable choice based on actual production conditions and is generally only enabled when the filtering effect is poor in actual operation. In this mode, the aperture of the second screen 242 is smaller than that of the first screen, thereby ensuring the filtering efficiency. It should be noted that in this working mode, the first manual valve 333 and the second manual valve 334 In the normally closed state, the dust shaken off by the two screens is collected in the first dust collecting trough 31 and the second dust collecting trough 32. In actual production, the first manual valve 333 and the second manual valve 334 can be opened and closed alternately at intervals, so that the dust is collected in the dust collecting tank 35. Since the first mode is mainly used in this embodiment, the first manual valve 333 and the second manual valve 334 are arranged on the Y-shaped tube 33. When the second mode is mainly used in other embodiments, it can also be set to an electric valve, which can be opened and closed alternately at intervals.

[0043] The third working mode of the present invention is a mode in which the first filter 23 and the second filter 24 are used separately. This mode is similar to the first mode, except that when a filter fails, such as when the ultrasonic transducer 244 is damaged, the other filter is used alone to work; in actual operation, the probability of both filters being damaged at the same time is particularly rare. The equipment will be maintained after each operation to ensure the normal use of the equipment. However, if both filters are damaged in actual production, it is only necessary to close all control valves and then replace the ultrasonic transducer 244. Due to the detachable connection of the ultrasonic transducer 244, the replacement can be completed in a few minutes in actual operation. For the crystal pulling furnace, the short-term retention of inert gas will not have much impact on the quality of the product, but frequent replacement should be avoided as much as possible.

[0044] In the present invention, the vacuum pressure gauge can assist in the judgment of equipment failure. For example, when the first screen is working, if the pressure difference between the two vacuum pressure gauges becomes smaller, it means that the screen itself may be damaged, and if the pressure difference becomes larger, it means that the ultrasonic transducer 244 may be damaged; similarly, if the second screen 242 is working, the vacuum pressure gauge at the front end of the second screen 242 is compared with the pressure of the vacuum pump, and the fault can also be judged; in other embodiments of the present invention, the detection value of the vacuum pressure gauge can be connected to the PLC control system, and each control valve can use an electric valve to realize automatic switching of the two screens in the event of a failure.

[0045] In the present invention, since the aperture of the screen is relatively small, about 630 meshes, an ultrasonic transducer 244 is used, and the vibration waves generated by the ultrasonic transducer can make the screen vibrate, thereby shaking off and collecting the dust on the screen. Therefore, there will be no dust residue on the screen, and the screen will not be blocked, thereby ensuring the stability of filtration. The shaken dust is collected in the dust collecting tank 35 through the Y-tube 33. After the operation is completed, the dust collecting tank 35 can be disassembled and cleaned.

[0046] In actual operation, in order to ensure the stability of dust collection, a small amount of airflow can be allowed to flow through the Y-tube 33, thereby driving the dust in the Y-tube 33 to fall into the dust collecting tank 35, so as to achieve stable collection of dust. In the process, the Venturi tube 13 is used. The negative pressure generated at the throat of the Venturi tube 13 can drive part of the gas in the filter 2 to flow back through the Y-tube 33. During the process, the amount of refluxed gas is controlled by the fourth control valve 361. In actual operation, the intake volume and the reflux gas volume can be controlled to be about 10:1. In addition, in order to prevent a large amount of dust from returning to the main intake pipe 1, a dust cover 332 is set at the entrance of the connecting port 331, which can effectively prevent a large amount of dust from flowing back.

[0047] In actual operation, if the dust collecting tank 35 is full, the dust collecting tank 35 can be cleaned and replaced. During the process, the third manual valve 34 under the Y-tube 33 is closed, and the Y-tube 33 and the dust collecting tank 35 can be isolated. At this time, the air pressure balance valve 352 on the dust collecting tank 35 is opened to remove the dust collecting tank 35. During the process, the dust collecting tank 35 and the Y-tube 33 can be connected in a variety of detachable ways such as flanges, mortise and tenon joints, and threads.

[0048] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A vacuum dust removal device for a single crystal silicon pulling furnace, characterized in that: including filters (2); The filter (2) is horizontal, one end of the filter (2) is provided with an air inlet (21), the other end of the filter (2) is provided with an air outlet (22), the air inlet (21) is connected to an air inlet pipe, the air inlet pipe is connected to a crystal pulling furnace, the air outlet (22) is connected to an air outlet pipe, and the air outlet pipe is connected to a vacuum pump; The filter (2) is provided with two filter screens, namely a first filter screen (23) and a second filter screen (24); the air intake pipe includes a main air intake pipe (1); the main air intake pipe (1) is divided into two pipes, namely a first air intake pipe (11) and a second air intake pipe (12); the first air intake pipe (11) is connected to the air intake port (21); a first connecting port (25) and a second connecting port (26) are respectively provided on the filter (2) shell between the first filter screen (23) and the second filter screen (24); the second air intake pipe (12) is connected to the first connecting port (25); a third connecting port (27) is provided on the filter (2) shell behind the second filter screen (24); the second connecting port (26) and the third connecting port (27) are connected through a connecting pipe (28); the third connecting port (27) is connected to an air distribution nozzle (29) inside the filter (2); The first air intake pipe (11) is provided with a first control valve (111), the second air intake pipe (12) is provided with a second control valve (121), and the connecting pipe (28) is provided with a third control valve (281); The first filter (23) and the second filter (24) have the same structure, wherein the second filter (24) comprises an ultrasonic filter frame (241), a screen (242) is mounted on the ultrasonic filter frame (241), and support bars (243) are arranged on both sides of the screen (242); an ultrasonic transducer (244) is detachably mounted on the ultrasonic filter frame (241), and the ultrasonic transducer (244) is located behind the support bar (243) on the rear side of the screen; The first filter screen (23) and the second filter screen (24) have multiple working modes, including alternating working, combined working and individual working.

2. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 1, characterized in that: The air distribution nozzle (29) is detachably connected to the third communication port (27). The air distribution nozzle (29) is fan-shaped. After the airflow passes through the air distribution nozzle (29), an air curtain is formed behind the second filter screen (24).

3. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 1, characterized in that: The invention also comprises a dust collecting system (3), wherein the dust collecting system (3) comprises two dust collecting grooves, namely a first dust collecting groove (31) and a second dust collecting groove (32), wherein the first dust collecting groove (31) is located in front of the first filter screen (23), and the second dust collecting groove (32) is located in front of the second filter screen (24).

4. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 3, characterized in that: The first dust collecting groove (31) and the second dust collecting groove (32) are connected to a Y-shaped tube (33) below, a first manual valve (333) is arranged on the branch pipe on the left side of the Y-shaped tube (33), a second manual valve (334) is arranged on the branch pipe on the right side of the Y-shaped tube, and the lower end of the Y-shaped tube (33) is detachably connected to a dust collecting tank (35).

5. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 4, characterized in that: When the first filter screen (23) and the second filter screen (24) work alternately, the aperture of the first filter screen (23) is consistent with the aperture of the second filter screen (24); if the first filter screen (23) is working, the second control valve (121) is closed, the third control valve (281) is opened, the first manual valve (333) is opened and the second manual valve (334) is closed; if the second filter screen (24) is working, the second control valve (121) is opened, the first control valve (111) is closed, the first manual valve (333) and the third control valve (281) are closed and the second manual valve (334) is opened.

6. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 4, characterized in that: When the first filter screen (23) and the second filter screen (24) work together, the aperture of the first filter screen (23) is larger than the aperture of the second filter screen (24), and at this time, the second control valve (121), the third control valve (281), the first manual valve (333) and the second manual valve (334) are closed at the same time; the first manual valve (333) and the second manual valve (334) are opened and closed alternately at a certain interval.

7. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 4, characterized in that: A third manual valve (34) is arranged on the vertical tube of the Y-shaped tube (33); the dust collecting tank (35) is detachably mounted below the vertical tube of the Y-shaped tube (33); an air pressure balance tube (351) is arranged on one side of the dust collecting tank (35); and an air pressure balance valve (352) is arranged on the air pressure balance tube (351).

8. The vacuum dust removal equipment for a single crystal silicon pulling furnace according to claim 7, characterized in that: The vertical pipe of the Y-shaped pipe (33) is provided with a connecting port (331) above the third manual valve (34), a venturi tube (13) is provided on the main air intake pipe (1), the connecting port (331) is connected to the throat of the venturi through a connecting pipe (36), a fourth control valve (361) is provided on the connecting pipe (36), and a dust cover (332) is provided at the inlet of the connecting port (331).

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