Metal blowing air pipe

Abstract

The invention relates to the technical field of metal blowing air pipes and discloses a metal blowing air pipe which comprises a metal pipe and supports, the supports are arranged at the upper end and the lower end of the metal pipe, a blowing ring is arranged outside the metal pipe, the left side of the blowing ring communicates with an air inlet, the air inlet end of the air inlet communicates with a control valve, and a control mechanism is arranged at the control end of the control valve. A pneumatic actuator is connected to the top of an inner cavity of the shell, a control shaft is connected to the control end of the pneumatic actuator, the bottom of the control shaft is connected with a valve rod of the control valve, and sensor sets are connected to the two sides of the inner cavity of the shell. According to the metal blowing air pipe, the gathering effect of cooling airflow is guaranteed, the optical fiber cooling efficiency is improved, helium is completely replaced with assistance to further reduce the production cost, the air cooling height does not need to be increased by increasing the height of a tower body like a traditional mode, and high-difficulty technical transformation and high transformation cost are avoided; and the modification requirement in actual production is met.

Description

Technical Field

[0001] This invention relates to the field of metal air blowing duct technology, specifically to metal air blowing ducts. Background Technology

[0002] In the high-speed fiber drawing process, in order to ensure the stability of the outer coating diameter of the fiber and guarantee the quality of the fiber product, it is necessary to cool the fiber during the drawing process. This process requires the use of a special airflow delivery and cooling control device. This type of device belongs to the field of fiber manufacturing equipment technology. Specifically, it is a cooling auxiliary device used in conjunction with the high-speed fiber drawing furnace. It is mainly used to provide directional cooling airflow for the fiber output from the drawing furnace and to help control the fiber temperature to meet the requirements of subsequent processing.

[0003] Currently, gas cooling devices are used in the cooling process of high-speed optical fiber drawing, with some devices using helium as the cooling medium. However, in practical applications, these devices suffer from inefficient helium utilization due to their inadequate helium delivery and distribution structure design. Furthermore, the high cost of helium itself results in consistently high helium consumption per unit of production, significantly increasing operating costs for companies in a market environment where helium prices remain high. Additionally, existing devices rely heavily on manual adjustment of the cooling airflow rate. Manual adjustment not only struggles to match the dynamic demands of the optical fiber cooling process in real time and achieve precise airflow rate control, but also easily leads to airflow instability due to operational delays or adjustment deviations. This results in uneven cooling of the optical fiber, affecting the consistency of the optical fiber coating diameter. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a metal air blowing duct to solve the technical problems mentioned above. Manual adjustment is not only difficult to match the dynamic requirements of the optical fiber cooling process in real time and cannot achieve precise control of airflow velocity, but also prone to airflow instability due to operation delays or adjustment deviations, resulting in uneven optical fiber cooling effect and affecting the consistency of the outer coating diameter of the optical fiber.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a metal air blowing duct, comprising: a metal tube and a support, wherein the support is disposed at the upper and lower ends of the metal tube, an air blowing ring is disposed on the outside of the metal tube, an air inlet is connected to the left side of the air blowing ring, a control valve is connected to the air inlet end of the air inlet, a control mechanism is disposed at the control end of the control valve, the control mechanism includes a housing, and a pneumatic actuator is connected to the top of the inner cavity of the housing; The control end of the pneumatic actuator is connected to a control shaft, the bottom of which is connected to the valve stem of the control valve. Sensor groups are connected to both sides of the inner cavity of the housing. A chuck is sleeved on the outside of the control shaft. Locking blocks are connected to both sides of the bottom of the pneumatic actuator. A cylinder is connected between the locking blocks and the pneumatic actuator. Locking grooves are evenly opened on the outside of the chuck, and the inner cavity of the locking groove is adapted to the outside of the locking block. The sensor array can monitor temperature and air velocity data in real time during the fiber optic cooling process and feed the signals back to the pneumatic actuator. The control shaft precisely adjusts the opening and closing of the control valve to achieve automatic and precise control of the compressed air velocity. This is more efficient and stable than manual adjustment, ensuring uniform fiber optic cooling and thus precisely controlling the outer coating diameter of the fiber to achieve the ideal value. After the cylinder-driven locking block is engaged in the locking slot of the chuck, the control shaft can be stably locked, preventing the valve from shifting due to airflow fluctuations, ensuring the stability of the air supply, and further improving the control accuracy of the fiber optic coating diameter.

[0006] The metal tube has an upper positioning ring at its top. A first bolt is installed between the bracket, the metal tube, and the upper positioning ring. A sleeve is slidably connected to the inner cavity of the upper positioning ring. A sealing strip is installed in the inner cavity of the upper positioning ring. A piston rod is connected to the outside of the sealing strip. A hollow column is sleeved on the outside of the piston rod. A short pipe is connected to the bottom of the hollow column. An air supply plate is connected to the bottom of the short pipe. A pump body is installed in the inner cavity of the air supply plate, and the control end of the pump body is connected to the sensor group. The sleeve can slide along the inner cavity of the upper positioning ring to adapt to the installation requirements of metal tubes of different specifications, enhancing the versatility of the device. The sensor group feeds back signals to the pump body of the air supply plate. The pump body drives the piston rod through a short pipe and hollow column to move the sealing strip to fit tightly into the sealing groove of the sleeve, realizing dynamic sealing at the connection between the metal pipe and the upper positioning ring, preventing compressed air leakage, improving gas utilization, and ensuring the gathering effect of cooling airflow, improving the cooling efficiency of optical fiber, and helping to completely replace helium to reduce production costs.

[0007] Preferably, a second bolt is provided on the outside of the bracket, and a washer is provided between the second bolt and the bracket; the washer can enhance the sealing and tightness of the connection between the second bolt and the bracket, prevent the bolt from loosening due to vibration during long-term operation of the device, ensure the fixing stability of the bracket to the metal tube and the upper positioning ring, indirectly ensure the stability of compressed air flow, and maintain the consistency of fiber optic cooling effect.

[0008] Preferably, the inner cavity of the bracket is provided with a reinforcing block, and the outer surface of the bracket is provided with a reinforcing rib; the triangular reinforcing block and the outer reinforcing rib can improve the structural strength and load-bearing capacity of the bracket, resist the impact force generated by the flow of compressed air and the operation of the device, avoid the deformation of the bracket, ensure the installation accuracy of the metal tube and the accuracy of airflow guidance, extend the service life of the device, and ensure the long-term stable achievement of the helium replacement goal.

[0009] Preferably, the inner cavity of the upper positioning ring is equipped with an assembly groove, and the inner cavity of the assembly groove is connected to the hollow column and the air supply plate by bolts; the assembly groove achieves a firm connection between the hollow column, the air supply plate and the upper positioning ring by bolts, which facilitates the disassembly and maintenance of components, while ensuring the coaxiality of the three, ensuring the precise movement of the pump body driving the sealing strip, ensuring the sealing effect and airflow control accuracy, and helping the device to stably perform the helium substitution function.

[0010] Preferably, the sleeve has a sealing groove on its outside, and the inner cavity of the sealing groove is slidably connected to the outside of the sealing strip. The sliding connection structure between the sealing groove and the sealing strip not only ensures the flexibility of the sleeve adjustment, but also achieves reliable sealing at different positions, prevents compressed air leakage, improves gas utilization, ensures that the cooling airflow is concentrated on the optical fiber, improves cooling efficiency, and better realizes helium substitution to reduce costs.

[0011] Preferably, the inner cavity of the housing is uniformly provided with locking frames, and the outside of the locking frames is connected to the outside of the pneumatic actuator by bolts; the locking frames fix the pneumatic actuator by bolts, which enhances its installation stability in the inner cavity of the housing, avoids displacement due to vibration during operation, ensures the connection accuracy between the control shaft and the control valve stem, ensures accurate valve adjustment, and thus stabilizes the compressed air flow rate, ensuring the cooling effect of the optical fiber and the control accuracy of the outer coating diameter.

[0012] Preferably, the top of the housing is provided with a dust cover, which is detachably connected to the top of the housing by bolts; the dust cover can prevent external dust and impurities from entering the inner cavity of the housing, avoid contamination or wear of precision components such as sensor groups and pneumatic actuators, ensure the operating accuracy and service life of the control mechanism, and ensure that the device can achieve the function of cooling by replacing helium with compressed air for a long time.

[0013] Preferably, the air inlet end of the air supply plate is equipped with a filter, which is fixedly connected to the inner cavity of the air supply plate. The filter can filter the gas entering the pump body, remove impurities and particulate matter in the air, prevent clogging of the pump body, short pipes or affecting the sealing effect of the sealing strip, ensure the smooth operation of the air supply system, maintain the cleanliness of compressed air and the stability of airflow, ensure uniform cooling effect of optical fiber, and help to accurately control the diameter of the outer coating of optical fiber.

[0014] Preferably, the reinforcing block has a triangular structure, and its two sides are welded and fixed to the inner cavity wall of the support. The welding and fixing method of the triangular reinforcing block to the inner cavity wall of the support further improves the connection strength, enhances the stability and deformation resistance of the overall structure of the support, ensures that the device maintains structural accuracy during long-term high-intensity operation, ensures accurate airflow guidance of compressed air, and stably achieves the core goal of helium substitution cooling.

[0015] Preferably, a sealing gasket is provided at the connection between the air inlet and the control valve. The sealing gasket is fitted over the outside of the air inlet and fits tightly against the control valve. The tight fit of the sealing gasket at the connection between the air inlet and the control valve enhances the sealing performance of the connection, prevents compressed air leakage, improves gas utilization, ensures sufficient airflow intensity for fiber optic cooling, guarantees the helium substitution effect, and reduces energy waste and production energy consumption.

[0016] Compared with the prior art, the present invention provides a metal air blowing duct, which has the following beneficial effects: This metal air-blowing duct cools optical fibers by blowing compressed air instead of helium, effectively addressing the high price of helium, reducing helium usage costs, and solving the problem of excessive helium consumption in current high-speed fiber drawing production. Its control mechanism's sensor array monitors temperature and airflow rate data in real time during the fiber cooling process and feeds the signals back to the pneumatic actuator. The actuator precisely adjusts the control valve opening and closing via the control shaft, achieving automatic and precise control of the compressed air flow rate. This is more efficient and stable than manual adjustment, ensuring uniform fiber cooling and thus precisely controlling the fiber coating diameter to achieve the ideal value. The cylinder-driven locking block engages with the locking groove of the chuck, providing a stable lock on the control shaft. This prevents valve displacement due to airflow fluctuations, ensuring stable air supply and further improving the control accuracy of the fiber optic coating diameter. The sleeve, slidably connected within the upper positioning ring at the top of the metal tube, can slide along the inner cavity of the upper positioning ring, adapting to the installation requirements of metal tubes of different specifications and enhancing the device's versatility. Furthermore, the sensor group can feed back signals to the pump body of the air supply plate. The pump body drives the piston rod through a short pipe and hollow column, which in turn drives the sealing strip to tightly fit the sealing groove of the sleeve, achieving dynamic sealing at the connection between the metal pipe and the upper positioning ring. This effectively prevents compressed air leakage, improves gas utilization, and ensures the gathering effect of the cooling airflow, thereby improving the cooling efficiency of the optical fiber. This helps to completely replace helium and further reduce production costs. Unlike traditional methods, it does not require increasing the height of the tower to increase the air cooling height, thus avoiding difficult technical modifications and high modification costs, and better meeting the modification needs in actual production. Attached Figure Description

[0017] Figure 1 This is a front view of the present invention; Figure 2 This is a planar schematic diagram of the present invention; Figure 3 This is a partial cross-sectional view of the positioning ring of the present invention; Figure 4 This is a schematic diagram of the external appearance of the sealing strip of the present invention; Figure 5 This is a cross-sectional view of the control mechanism of the present invention.

[0018] In the diagram: 1. Air blowing ring; 2. Bracket; 21. Reinforcing block; 3. Metal tube; 4. Upper positioning ring; 41. Sleeve; 42. Sealing strip; 43. Piston rod; 44. Hollow column; 45. Short tube; 46. Air supply plate; 5. First bolt; 6. Second bolt; 7. Air inlet; 8. Control valve; 9. Control mechanism; 91. Housing; 92. Pneumatic actuator; 93. Locking frame; 94. Sensor group; 95. Control shaft; 96. Chuck; 97. Locking block. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a technical solution; please refer to [link / reference]. Figure 1 and Figure 2 A metal air blowing duct includes: a metal pipe 3 and a bracket 2. The bracket 2 is disposed at the upper and lower ends of the metal pipe 3. An air blowing ring 1 is disposed on the outside of the metal pipe 3. An air inlet 7 is connected to the left side of the air blowing ring 1. A control valve 8 is connected to the air inlet end of the air inlet 7. A control mechanism 9 is disposed at the control end of the control valve 8. The control mechanism 9 includes a housing 91. A pneumatic actuator 92 is connected to the top of the inner cavity of the housing 91. The control end of the pneumatic actuator 92 is connected to the control shaft 95. The bottom of the control shaft 95 is connected to the valve stem of the control valve 8. Sensor groups 94 are connected to both sides of the inner cavity of the housing 91. A chuck 96 is sleeved on the outside of the control shaft 95. A locking block 97 is connected to both sides of the bottom of the pneumatic actuator 92. A cylinder is connected between the locking block 97 and the pneumatic actuator 92. Locking grooves are evenly opened on the outside of the chuck 96, and the inner cavity of the locking groove is adapted to the outside of the locking block 97. Please see Figure 3 and Figure 4The sensor group 94 can monitor the temperature data and air flow rate data in real time during the fiber cooling process and feed the signal back to the pneumatic actuator 92. The control shaft 95 precisely adjusts the opening and closing degree of the control valve 8 to achieve automatic and precise control of the compressed air flow rate. Compared with manual adjustment, it is more efficient and stable, ensuring uniform fiber cooling effect and thus precisely controlling the outer coating diameter of the fiber to reach the ideal value. After the cylinder drive block 97 is engaged in the locking slot of the chuck 96, the control shaft 95 can be stably locked, avoiding valve displacement caused by airflow fluctuations, ensuring air supply stability, and further improving the control accuracy of the fiber outer coating diameter.

[0021] Please see Figure 4 and Figure 5 The top of the metal tube 3 is provided with an upper positioning ring 4. A first bolt 5 is provided between the bracket 2, the metal tube 3, and the upper positioning ring 4. A sleeve 41 is slidably connected to the inner cavity of the upper positioning ring 4. A sealing strip 42 is provided in the inner cavity of the upper positioning ring 4. A piston rod 43 is connected to the outside of the sealing strip 42. A hollow column 44 is sleeved on the outside of the piston rod 43. A short pipe 45 is connected to the bottom of the hollow column 44. An air supply plate 46 is connected to the bottom of the short pipe 45. A pump body is provided in the inner cavity of the air supply plate 46, and the control end of the pump body is connected to the sensor group 94. The sleeve 41 can slide along the inner cavity of the upper positioning ring 4 to adapt to the installation requirements of metal tubes 3 of different specifications and enhance the versatility of the device. The sensor group 94 feeds back signals to the pump body of the air supply plate 46. The pump body drives the piston rod 43 through the short pipe 45 and the hollow column 44, which in turn drives the sealing strip 42 to tightly fit the sealing groove of the sleeve 41, thereby achieving dynamic sealing at the connection between the metal pipe 3 and the upper positioning ring 4. This prevents compressed air leakage, improves gas utilization, and ensures the gathering effect of the cooling airflow, thereby improving the cooling efficiency of the optical fiber and helping to completely replace helium to reduce production costs.

[0022] The bracket 2 is provided with a second bolt 6 on its outside, and a washer is provided between the second bolt 6 and the bracket 2. The washer can enhance the sealing and tightness of the connection between the second bolt 6 and the bracket 2, prevent the bolt from loosening due to vibration during long-term operation of the device, ensure the fixing stability of the bracket 2 to the metal tube 3 and the upper positioning ring 4, indirectly ensure the stability of compressed air flow, and maintain the consistency of fiber optic cooling effect.

[0023] The inner cavity of the support 2 is provided with a reinforcing block 21, and the outer surface of the support 2 is provided with reinforcing ribs. The triangular reinforcing block 21 and the outer reinforcing ribs can improve the structural strength and load-bearing capacity of the support 2, resist the impact force generated by the flow of compressed air and the operation of the device, prevent the support 2 from deforming, ensure the installation accuracy of the metal tube 3 and the accuracy of airflow guidance, extend the service life of the device, and ensure the long-term stable achievement of the helium replacement goal.

[0024] The inner cavity of the upper positioning ring 4 is equipped with an assembly groove, and the inner cavity of the assembly groove is connected to the hollow column 44 and the air supply plate 46 by bolts. The assembly groove achieves a firm connection between the hollow column 44, the air supply plate 46 and the upper positioning ring 4 by bolts, which facilitates the disassembly and maintenance of components, while ensuring the coaxiality of the three, ensuring the precise movement of the pump body driving the sealing strip 42, ensuring the sealing effect and airflow control accuracy, and helping the device to stably perform the helium substitution function.

[0025] The sleeve 41 has a sealing groove on its outside, and the inner cavity of the sealing groove is slidably connected to the outside of the sealing strip 42. The sliding connection structure between the sealing groove and the sealing strip 42 not only ensures the flexibility of the sleeve 41 adjustment, but also achieves reliable sealing at different positions, prevents compressed air leakage, improves gas utilization, ensures that the cooling airflow is concentrated on the optical fiber, improves cooling efficiency, and better realizes helium substitution to reduce costs.

[0026] Locking frames 93 are evenly arranged in the inner cavity of housing 91. The outside of the locking frames 93 is connected to the outside of the pneumatic actuator 92 by bolts. The locking frames 93 fix the pneumatic actuator 92 by bolts, which enhances its installation stability in the inner cavity of housing 91, avoids displacement due to vibration during operation, ensures the connection accuracy between the control shaft 95 and the valve stem of the control valve 8, ensures accurate valve adjustment, and thus stabilizes the control of compressed air flow rate, ensuring the cooling effect of optical fiber and the control accuracy of the outer coating diameter.

[0027] A dust cover is provided on the top of the housing 91. The dust cover is detachably connected to the top of the housing 91 by bolts. The dust cover can prevent external dust and impurities from entering the inner cavity of the housing 91, avoid contamination or wear of precision components such as the sensor group 94 and the pneumatic actuator 92, ensure the operating accuracy and service life of the control mechanism 9, and ensure that the device can achieve the function of cooling by replacing helium with compressed air for a long time.

[0028] A filter is provided at the pump inlet end of the air supply plate 46, and the filter is fixedly connected to the inner cavity of the air supply plate 46. The filter can filter the gas entering the pump body, remove impurities and particles in the air, prevent blockage of the pump body, short pipe 45 or affect the sealing effect of the sealing strip 42, ensure the smooth operation of the air supply system, maintain the cleanliness of compressed air and the stability of airflow, ensure uniform cooling effect of optical fiber, and help to accurately control the diameter of the outer coating of optical fiber.

[0029] The reinforcing block 21 has a triangular structure, and its two sides are welded and fixed to the inner cavity wall of the support 2. The welding and fixing method of the triangular reinforcing block 21 to the inner cavity wall of the support 2 further improves the connection strength, enhances the stability and deformation resistance of the overall structure of the support 2, ensures that the device maintains structural accuracy during long-term high-intensity operation, ensures accurate airflow guidance of compressed air, and stably achieves the core goal of helium substitution cooling.

[0030] A sealing gasket is provided at the connection between the air inlet 7 and the control valve 8. The sealing gasket is fitted on the outside of the air inlet 7 and fits tightly against the control valve 8. The sealing gasket fits tightly against the connection between the air inlet 7 and the control valve 8, which enhances the sealing of the connection between the two, prevents compressed air leakage, improves gas utilization, ensures sufficient airflow intensity for fiber optic cooling, ensures the effect of helium substitution, and at the same time reduces energy waste and lowers production energy consumption.

[0031] In this scheme, the sleeve 41 is welded to the pipe of the device. When the upper positioning ring 4 needs to be connected, the upper positioning ring 4 is first inserted into the outside of the sleeve 41 and pushed upward. Then, the air inlet pipe of the control valve 8 is connected to the external air pipe. When the sensor group 94 receives the external gas signal, it drives the air supply plate 46 to supply air to the hollow column 44, which in turn pushes the hollow column 44 to drive the sealing strip 42 to be inserted into the inner cavity of the sleeve 41, limiting and locking the position of the upper positioning ring 4. The pneumatic actuator 92 controls the amount and flow rate of gas entering the control valve 8 and the air inlet 7. When the amount of gas entering is fixed, the locking block 97 is activated to insert into the inner cavity of the chuck 96 to limit the position of the control shaft 95, thereby limiting the valve stem of the control valve 8.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Metal air blowing duct, including: A metal tube (3) and a support (2), wherein the support (2) is disposed at the upper and lower ends of the metal tube (3), and an air blowing ring (1) is disposed on the outside of the metal tube (3). The air blowing ring (1) is characterized in that: an air inlet (7) is connected to the left side of the air blowing ring (1), and a control valve (8) is connected to the air inlet end of the air inlet (7). A control mechanism (9) is disposed at the control end of the control valve (8). The control mechanism (9) includes a housing (91), and a pneumatic actuator (92) is connected to the top of the inner cavity of the housing (91). The control end is connected to a control shaft (95), the bottom of which is connected to the valve stem of the control valve (8). Sensor groups (94) are connected to both sides of the inner cavity of the housing (91). A chuck (96) is sleeved on the outside of the control shaft (95). A locking block (97) is connected to both sides of the bottom of the pneumatic actuator (92). A cylinder is connected between the locking block (97) and the pneumatic actuator (92). Locking grooves are evenly opened on the outside of the chuck (96), and the inner cavity of the locking groove is adapted to the outside of the locking block (97). The top of the metal tube (3) is provided with an upper positioning ring (4), and the bracket (2) is provided with a first bolt (5) between the metal tube (3) and the upper positioning ring (4). The inner cavity of the upper positioning ring (4) is slidably connected with a sleeve (41). The inner cavity of the upper positioning ring (4) is provided with a sealing strip (42). The outside of the sealing strip (42) is connected with a piston rod (43). The outside of the piston rod (43) is fitted with a hollow column (44). The bottom of the hollow column (44) is connected with a short pipe (45). The bottom of the short pipe (45) is connected with an air supply plate (46). The inner cavity of the air supply plate (46) is provided with a pump body, and the control end of the pump body is connected to the sensor group (94).

2. The metal air blowing duct according to claim 1, characterized in that: The bracket (2) is provided with a second bolt (6) on its outside, and a washer is provided between the second bolt (6) and the bracket (2).

3. The metal air blowing duct according to claim 1, characterized in that: The inner cavity of the bracket (2) is provided with a reinforcing block (21), and the outer surface of the bracket (2) is provided with reinforcing ribs.

4. The metal air blowing duct according to claim 1, characterized in that: The inner cavity of the upper positioning ring (4) is equipped with an assembly groove, and the inner cavity of the assembly groove is connected to the hollow column (44) and the air supply plate (46) by bolts.

5. The metal air blowing duct according to claim 1, characterized in that: The sleeve (41) has a sealing groove on its outside, and the inner cavity of the sealing groove is slidably connected to the outside of the sealing strip (42).

6. The metal air blowing duct according to claim 1, characterized in that: The inner cavity of the housing (91) is uniformly provided with locking frames (93), and the outside of the locking frames (93) is connected to the outside of the pneumatic actuator (92) by bolts.

7. The metal air blowing duct according to claim 1, characterized in that: The top of the housing (91) is provided with a dust cover, which is detachably connected to the top of the housing (91) by bolts.

8. The metal air blowing duct according to claim 1, characterized in that: The air supply plate (46) has a filter at the pump inlet end, and the filter is fixedly connected to the inner cavity of the air supply plate (46).

9. The metal air blowing duct according to claim 1, characterized in that: The reinforcing block (21) has a triangular structure, and the two sides of the reinforcing block (21) are welded and fixed to the inner wall of the bracket (2).

10. The metal air blowing duct according to claim 1, characterized in that: A sealing gasket is provided at the connection between the air inlet (7) and the control valve (8). The sealing gasket is fitted over the outside of the air inlet (7) and fits tightly against the control valve (8).

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