Furnace tube structure and diffusion device
By incorporating multiple branch pipe structures into the furnace tube structure of the diffusion furnace, the effective area of the extraction port is increased, thus solving the turbulence problem caused by the increased gas flow rate, improving the stability of the thermal and gas fields, and enhancing the production yield and performance of the solar cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TRINA SOLAR CO LTD
- Filing Date
- 2025-05-07
- Publication Date
- 2026-06-02
AI Technical Summary
The exhaust method of existing diffusion furnaces leads to increased gas flow rate, resulting in lower temperature and turbulence near the exhaust port, which affects the uniformity of the thermal and gas fields in cell production, and consequently affects production yield and performance.
Multiple branch pipe structures are set in the furnace tube structure to increase the effective area of the exhaust port, reduce the gas flow velocity, reduce the influence of turbulence, and improve the stability of the thermal field and gas field.
By increasing the effective area of the extraction port, the gas flow rate was reduced, the uniformity of the thermal and gas fields was improved, and the production yield and performance of the solar cells were increased.
Smart Images
Figure CN224319802U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar photovoltaic cell manufacturing technology, and in particular to a furnace tube structure and diffusion device. Background Technology
[0002] Solar photovoltaic cells are key components for generating electricity using solar energy, and their conversion efficiency directly affects the performance of solar power generation. Phosphorus and boron diffusion processes are crucial steps in the production of solar photovoltaic cells; the uniformity of doping on the cell surface directly impacts the performance of the solar photovoltaic cell, and the diffusion furnace is an essential piece of equipment for the phosphorus and boron diffusion processes in solar cells.
[0003] In related technologies, the tail exhaust method of diffusion furnaces generally involves an exhaust pipe running directly from the tail of the furnace tube to the furnace opening, with the exhaust pipe located at the bottom inside the furnace tube. The exhaust port of the exhaust pipe has a simple circular horizontal cut structure. Due to the small diameter of the exhaust port and the high extraction speed, the gas velocity near the exhaust port increases. This increased gas velocity inevitably leads to a decrease in temperature near the exhaust port and the generation of turbulence, resulting in uneven gas concentration distribution near the exhaust port. This affects the thermal and gas fields of the furnace tube, and consequently, the production yield and performance of the battery.
[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Utility Model Content
[0005] This application provides a furnace tube structure and a diffusion device to solve or alleviate one or more of the technical problems mentioned above.
[0006] As a first aspect of the embodiments of this application, the embodiments of this application provide a furnace tube structure, including:
[0007] The furnace tube body has a cavity provided therein for accommodating silicon wafers;
[0008] An air extraction pipe is disposed on the inner wall forming the cavity; one end of the air extraction pipe is provided with an air extraction assembly, which includes multiple branch pipes.
[0009] In this configuration, multiple bronchial tubes are connected to the suction tube.
[0010] Optionally, the air extraction assembly includes a first branch and a second branch extending along different paths on the inner wall; one end of the first branch is connected to the air extraction tube, and the other end is provided with a first air extraction port; one end of the second branch is connected to the air extraction tube, and the other end is provided with a second air extraction port.
[0011] Wherein, the perimeter of the cross-section of the furnace tube body is C, and the distance from the first exhaust port to the second exhaust port along the inner wall forming the cavity is greater than or equal to 1 / 4C and less than or equal to 3 / 4C.
[0012] Optionally, the air extraction assembly further includes a third branch pipe connected to the air extraction pipe, and the end of the third branch pipe away from the air extraction pipe is provided with a third air extraction port for drawing special gas from the cavity, and the third air extraction port is located in the middle between the first air extraction port and the second air extraction port.
[0013] The third bronchus is coaxial with the suction pipe.
[0014] Optionally, the first bronchus and the second bronchus are symmetrically arranged with the third bronchus as the axis of symmetry.
[0015] Optionally, the first air extraction port, the second air extraction port, and the third air extraction port are evenly distributed on the inner wall forming the cavity.
[0016] Optionally, the first bronchus, the second bronchus, and the third bronchus are detachably and independently connected to the suction tube.
[0017] Optionally, the first air extraction port, the second air extraction port, and the third air extraction port are each and independently arranged in a trumpet-shaped structure.
[0018] Optionally, the diameter of the first bronchus gradually decreases along the direction of the first bronchus near the suction tube; and / or
[0019] Along the direction of the second bronchus near the suction tube, the diameter of the second bronchus gradually decreases; and / or
[0020] Along the direction of the third bronchus towards the suction tube, the diameter of the third bronchus gradually decreases.
[0021] Optionally, a first arc-shaped cover is provided at the end of the first bronchus away from the suction tube. The first arc-shaped cover has a plurality of first through holes evenly spaced and communicating with the first suction port. The total area of the plurality of first through holes is the same as the area of the first suction port; and / or
[0022] The end of the second bronchus away from the suction tube is provided with a second arc-shaped cover. The second arc-shaped cover has a plurality of second through holes evenly spaced and communicating with the second suction port. The total area of the plurality of second through holes is the same as the area of the second suction port; and / or
[0023] The third bronchus is provided with a third arc-shaped cover at the end away from the suction pipe. The third arc-shaped cover is provided with a plurality of third through holes that communicate with the third suction port at even intervals. The total area of the plurality of third through holes is the same as the area of the third suction port.
[0024] As a second aspect of the present application, the present application provides a diffusion device, which includes the furnace tube structure described above.
[0025] The embodiments of this application employing the above-described technical solution may have the following advantages:
[0026] By setting up multiple bronchus structures, the effective area of the bronchus's suction port can be increased during suction, and the gas flow velocity near the suction port can be reduced. This reduces the adverse effects of suction on the thermal and gas fields, effectively increasing the stability of the thermal field, the uniformity and stability of the gas field, and thus improving the production yield and performance of the battery. Attached Figure Description
[0027] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.
[0028] Figure 1 This is a partial structural diagram of the furnace tube structure provided in the embodiments of this application.
[0029] Figure 2 This is a front view of the furnace tube structure provided in the embodiments of this application.
[0030] Figure 3 This is a sectional view of the side view of the furnace tube structure provided in the embodiments of this application.
[0031] Figure 4 This is a sectional view of the top view of the furnace tube structure provided in the embodiments of this application.
[0032] Explanation of reference numerals in the attached figures:
[0033] 1. Furnace tube body; 11. Cavity; 12. Furnace tail; 13. Furnace opening; 2. Exhaust pipe; 21. First branch pipe; 211. First exhaust port; 22. Second branch pipe; 221. Second exhaust port; 23. Third branch pipe; 231. Third exhaust port. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The application will now be described in detail with reference to the accompanying drawings and embodiments.
[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0036] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.
[0037] Firstly, such as Figures 1-4 As shown, this application provides a furnace tube structure, which may include:
[0038] The furnace tube body 1 has a cavity 11 inside, which is used to accommodate silicon wafers; one end of the furnace tube body 1 is provided with a furnace tail 12, and the other end is provided with a furnace opening 13.
[0039] The exhaust pipe 2 is disposed on the inner wall of the cavity 11; an exhaust assembly is provided at one end of the exhaust pipe 2 near the furnace opening 13, and the exhaust assembly includes multiple branch pipes.
[0040] Multiple bronchi are connected to the suction pipe 2.
[0041] In this embodiment, by setting multiple bronchus structures, the effective area of the bronchus's extraction port can be increased during gas extraction, reducing the gas flow velocity near the extraction port. This reduces the adverse effects of gas extraction on the thermal and gas fields, effectively increasing the stability of the thermal field, the uniformity and stability of the gas field, and thus improving the battery's production yield and performance. In this embodiment, the furnace opening 13 of the furnace tube body 1 can be sealed with a cover plate.
[0042] It should be noted that in related technologies, when the extraction speed is high, the gas velocity near the extraction port increases. This increased gas velocity inevitably leads to a decrease in temperature near the extraction port, thus affecting the thermal field of the furnace tube. Furthermore, the increased gas velocity inevitably generates turbulence, resulting in uneven gas concentration distribution near the port, which also affects the gas field. In this embodiment, by setting multiple branch pipe structures at the end of the extraction pipe 2, the effective extraction area is increased several times over. This increase in effective area reduces the flow velocity near the extraction port, thus minimizing the impact on the gas and thermal fields. Moreover, the extraction pipe 2 and the multiple branch pipe structures in this application increase the effective area of the extraction port while minimizing the area obstructing the thermocouples on the inner wall of the cavity 11, thereby reducing the impact on the thermal field.
[0043] In an optional embodiment, the extraction assembly includes a first branch pipe 21 and a second branch pipe 22 extending along different paths on the inner wall. One end of the first branch pipe 21 is connected to the extraction pipe 2, and the other end is provided with a first extraction port 211 for extracting special gas from the cavity 11. One end of the second branch pipe 22 is connected to the extraction pipe 2, and the other end is provided with a second extraction port 221 for extracting special gas from the cavity 11. The perimeter of the furnace tube body 1 is C, and the distance from the first extraction port 211 along the inner wall of the cavity 11 to the second extraction port 221 is greater than or equal to 1 / 4C and less than or equal to 3 / 4C. The furnace tube body 1 can be a square tube structure or a cylindrical structure; in this embodiment, the furnace tube body 1 can be a cylindrical structure. The first branch pipe 21 and the second branch pipe 22 can be disposed on the inner wall, effectively improving the stability of their installation.
[0044] In this embodiment, during tail exhaust extraction, the special gas in the cavity 11 enters the first branch pipe 21 and the second branch pipe 22 through the first extraction port 211 and the second extraction port 221, respectively, and then the special gas is discharged from the furnace tube through the extraction pipe 2. In this embodiment, the perimeter of the cross-section of the furnace tube body 1 is C, and the distance between the first extraction port 211 and the second extraction port 221 is greater than or equal to 1 / 4C and less than or equal to 3 / 4C, so that the positions of the first extraction port 211 and the second extraction port 221 are relatively far apart, which can more evenly extract the special gas, is less likely to cause turbulence, and increases the effective extraction area. As a result, the gas velocity near the first extraction port 211 and the second extraction port 221 is reduced, which reduces the adverse effects on the thermal field and the gas field.
[0045] In an optional embodiment, the air extraction assembly further includes a third branch pipe 23 connected to the air extraction pipe 2. The end of the third branch pipe 23 away from the air extraction pipe 2 is provided with a third air extraction port 231 for extracting special gas from the cavity 11. The third air extraction port 231 is located in the middle between the first air extraction port 211 and the second air extraction port 221. The third branch pipe 23 is coaxially arranged with the air extraction pipe 2.
[0046] In this embodiment, during tail exhaust evacuation, the special gas in the cavity 11 enters the first branch pipe 21, the second branch pipe 22, and the third branch pipe 23 through the first evacuation port 211, the second evacuation port 221, and the third evacuation port 231, respectively, and then the special gas is discharged from the furnace tube through the evacuation pipe 2. The setting of the third evacuation port 231 further increases the effective evacuation area based on the first evacuation port 211 and the second evacuation port 221, thereby reducing the gas flow velocity near the first evacuation port 211, the second evacuation port 221, and the third evacuation port 231, reducing the adverse effects on the thermal field and the gas field.
[0047] In an optional embodiment, the first bronchus 21 and the second bronchus 22 are symmetrically arranged about the third bronchus 23 as an axis of symmetry. This symmetrical arrangement of the first bronchus 21 and the second bronchus 22 about the third bronchus 23 ensures that the first suction port 211, the second suction port 221, and the third suction port 231 are distributed, thereby enabling a more stable and uniform removal of the special gas from the cavity 11 and mitigating the problem of accelerated gas flow during suction.
[0048] In some embodiments, the inner wall of the cavity 11 corresponding to the third branch pipe 23 is the top wall of the furnace tube. The distance from the top wall to the first exhaust port 211 is S1, the distance from the top wall to the second exhaust port 221 is S2, and the distance from the top wall to the third exhaust port 231 is S3; wherein, S3 is greater than S1 and S2, respectively. It should be noted that in the related art, the exhaust port of the exhaust pipe is located at the bottom, while the special gas in the furnace tube is at different positions and at different distances from the exhaust port. When the exhaust port starts to exhaust, the special gas at different positions will generate turbulence when it gathers towards the exhaust port, and the different flow rates of the special gas at different positions will cause fluctuations in the thermal field, thus affecting the uniformity of diffusion. In this embodiment, by setting a first branch pipe 21, a second branch pipe 22 and a third branch pipe 23, and the distance from the special gas near the top wall of the furnace tube to the first extraction port 211 and the second extraction port 221 is shorter than the distance to the third extraction port 231, turbulence is less likely to be caused, the stability of the thermal field can also be improved, thereby improving the uniformity of diffusion.
[0049] In an optional embodiment, the first suction port 211, the second suction port 221, and the third suction port 231 are evenly distributed on the inner wall of the cavity 11. The evenly distributed first suction port 211, second suction port 221, and third suction port 231 can further reduce the gas flow rate of the special gas during suction, which is beneficial to the stability of the gas field.
[0050] In an optional embodiment, the first branch pipe 21, the second branch pipe 22, and the third branch pipe 23 are detachably and independently connected to the extraction pipe 2. During actual production, the first branch pipe 21, the second branch pipe 22, and the third branch pipe 23 can be replaced according to different production requirements, thereby adjusting the positions of the first extraction port 211, the second extraction port 221, and the third extraction port 231 within the furnace tube. Furthermore, the first branch pipe 21, the second branch pipe 22, and the third branch pipe 23 can also be replaced when damaged, thus improving the service life of the furnace tube.
[0051] In an optional embodiment, the first extraction port 211, the second extraction port 221, and the third extraction port 231 are each and independently arranged in a trumpet-shaped structure. The trumpet-shaped first extraction port 211, second extraction port 221, and third extraction port 231 can expand the extraction area and alleviate the problem of velocity concentration, thereby reducing the local gas velocity and further reducing the impact on the thermal field and the gas field.
[0052] In an optional embodiment, the diameter of the first bronchus 21 gradually decreases along the direction of the first bronchus 21 approaching the suction pipe 2; and / or the diameter of the second bronchus 22 gradually decreases along the direction of the second bronchus 22 approaching the suction pipe 2; and / or the diameter of the third bronchus 23 gradually decreases along the direction of the third bronchus 23 approaching the suction pipe 2. As the diameters of the first bronchus 21, the second bronchus 22, and the third bronchus 23 gradually decrease, the gas velocity in the region outside the pipe openings decreases, forming a low-pressure zone. This increases the stability of the thermal field, the uniformity of the gas field, and the processing stability, thereby improving the production yield.
[0053] In an optional embodiment, the end of the first bronchus 21 away from the suction pipe 2 is provided with a first arc-shaped cover, and the first arc-shaped cover is provided with a plurality of first through holes that communicate with the first suction port 211 at even intervals, the total area of the plurality of first through holes being the same as the area of the first suction port 211; and / or the end of the second bronchus 22 away from the suction pipe 2 is provided with a second arc-shaped cover, and the second arc-shaped cover is provided with a plurality of second through holes that communicate with the second suction port 221 at even intervals, the total area of the plurality of second through holes being the same as the area of the second suction port 221; and / or the end of the third bronchus 23 away from the suction pipe 2 is provided with a third arc-shaped cover, and the third arc-shaped cover is provided with a plurality of third through holes that communicate with the third suction port 231 at even intervals, the total area of the plurality of third through holes being the same as the area of the third suction port 231. The design of the first through hole, the second through hole, and the third through hole can uniformly distribute the special gas velocity to the first extraction port 211, the second extraction port 221, and the third extraction port 231, respectively. This can reduce the turbulence of the special gas flow and improve its stability, thereby significantly reducing the flow velocity of the special gas near the first extraction port 211, the second extraction port 221, and the third extraction port 231. This, in turn, increases the stability of the thermal field, the uniformity and stability of the gas field, and improves the production yield.
[0054] Secondly, this application also provides a diffusion device, which includes the furnace tube structure of any of the above embodiments.
[0055] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0056] For ease of description, directional terms such as "front, back, up, down, left, right," "horizontal, vertical, horizontal," and "top, bottom" generally indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms 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 limiting the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the components themselves. For example, if a device in the drawings is inverted, a device described as "above" or "on top of" other devices or structures will subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.
[0057] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0058] Unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0059] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.
[0060] It should also be noted that the terms "one embodiment," "another embodiment," or "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.
[0061] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0062] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.
Claims
1. A furnace tube structure, characterized in that, include: Furnace tube body (1), wherein a cavity (11) is provided in the furnace tube body (1) and the cavity (11) is used to accommodate silicon wafers; An air extraction pipe (2) is disposed on the inner wall forming the cavity (11); one end of the air extraction pipe (2) is provided with an air extraction assembly, which includes multiple bronchial pipes; Among them, multiple of the bronchi are connected to the suction pipe (2).
2. The furnace tube structure according to claim 1, characterized in that, The air extraction assembly includes a first branch pipe (21) and a second branch pipe (22) extending along different paths on the inner wall respectively; one end of the first branch pipe (21) is connected to the air extraction pipe (2), and the other end is provided with a first air extraction port (211); one end of the second branch pipe (22) is connected to the air extraction pipe (2), and the other end is provided with a second air extraction port (221); Wherein, the perimeter of the cross-section of the furnace tube body (1) is C, and the distance from the first exhaust port (211) along the inner wall forming the cavity (11) to the second exhaust port (221) is greater than or equal to 1 / 4C and less than or equal to 3 / 4C.
3. The furnace tube structure according to claim 2, characterized in that, The air extraction assembly also includes a third branch pipe (23) connected to the air extraction pipe (2). The end of the third branch pipe (23) away from the air extraction pipe (2) is provided with a third air extraction port (231) for drawing special gas from the cavity (11). The third air extraction port (231) is located between the first air extraction port (211) and the second air extraction port (221). The third bronchus (23) is coaxial with the suction pipe (2).
4. The furnace tube structure according to any one of claims 1 to 3, characterized in that, The first bronchus (21) and the second bronchus (22) are symmetrically arranged with the third bronchus (23) as the axis of symmetry.
5. The furnace tube structure according to any one of claims 1 to 3, characterized in that, The first air extraction port (211), the second air extraction port (221) and the third air extraction port (231) are evenly distributed on the inner wall of the cavity (11).
6. The furnace tube structure according to any one of claims 1 to 3, characterized in that, The first bronchus (21), the second bronchus (22) and the third bronchus (23) are detachably and independently connected to the suction tube (2).
7. The furnace tube structure according to any one of claims 1 to 3, characterized in that, The first air extraction port (211), the second air extraction port (221) and the third air extraction port (231) are respectively and independently arranged in a trumpet-shaped structure.
8. The furnace tube structure according to any one of claims 1 to 3, characterized in that, Along the direction of the first bronchus (21) near the suction tube (2), the diameter of the first bronchus (21) gradually decreases; and / or Along the direction of the second bronchus (22) near the suction tube (2), the diameter of the second bronchus (22) gradually decreases; and / or Along the direction of the third bronchus (23) near the suction tube (2), the diameter of the third bronchus (23) gradually decreases.
9. The furnace tube structure according to any one of claims 1 to 3, characterized in that, The first bronchus (21) has a first arc-shaped cover at the end away from the suction pipe (2). The first arc-shaped cover has a plurality of first through holes evenly spaced and communicating with the first suction port (211). The total area of the plurality of first through holes is the same as the area of the first suction port (211); and / or The second bronchus (22) has a second arc-shaped cover at the end away from the suction pipe (2). The second arc-shaped cover has a plurality of second through holes evenly spaced on it, communicating with the second suction port (221). The total area of the plurality of second through holes is the same as the area of the second suction port (221); and / or The third bronchus (23) is provided with a third arc-shaped cover at the end away from the suction pipe (2). The third arc-shaped cover is provided with a plurality of third through holes that communicate with the third suction port (231) at even intervals. The total area of the plurality of third through holes is the same as the area of the third suction port (231).
10. A diffusion device, characterized in that, Includes the furnace tube structure as described in any one of claims 1 to 9.