Hot air distributor for multi-spray-gun spray drying tower

Abstract

The invention discloses a hot air distributor for a multi-spray-gun spray drying tower, and belongs to the technical field of hot air drying equipment. The hot air distributor comprises an L-shaped flow guide air duct, a hot air distribution chamber, a plurality of spray gun air distribution barrels and spray guns, wherein the outlet end of the L-shaped flow guide air duct is connected to the center of a top cover of the hot air distribution chamber; the hot air distribution chamber is enclosed by a hot air distribution chamber top cover, a hot air distribution chamber wall body and an air heat insulation layer below the hot air distribution chamber wall body; a plurality of spray gun air distribution barrels are uniformly distributed in the hot air distribution chamber in the circumferential direction, an inlet of each spray gun air distribution barrel is communicated with the hot air distribution chamber, and an outlet of each spray gun air distribution barrel downwards penetrates through the air heat insulation layer and leads to the interior of the drying tower; the number of the spray guns corresponds to that of the spray gun air distribution barrels, and each spray gun coaxially penetrates through the corresponding spray gun air distribution barrel. The technical effects of uniform air distribution of the spray guns, low system flow resistance, good wall adhesion resistance of the tower top and flexible spray gun layout are achieved, and the problems that hot air distribution of multiple spray guns is not uniform, energy consumption is high, and materials are prone to adhesion are effectively solved.

Description

Technical Field

[0001] This invention relates to a spray drying tower, and more particularly to a hot air distributor for a multi-gun spray drying tower, belonging to the technical field of hot air drying equipment. Background Technology

[0002] Spray drying towers are used for drying materials in fields such as biopesticides, pharmaceuticals, and food microbiology. Their working principle involves dispersing the raw material liquid into droplets via an atomizer, which then come into direct contact with hot air or other heat-transmitting gases to obtain a powdered or granular product. The internal flow field distribution and airflow uniformity within the drying tower have a significant impact on the drying effect, a common problem that has long been faced by the drying industry.

[0003] For high-volume pressure spray drying towers, due to the flow rate limit of a single spray gun, multiple spray guns are usually used in parallel to increase production capacity. The hot air distribution at each spray gun nozzle directly affects the drying efficiency, product particle size, and moisture content of the corresponding spray mist. To ensure the consistency of product quality from each spray gun, the hot air distribution at each spray gun must be highly consistent.

[0004] Currently, the main structural types used for hot air distribution in multi-gun spray drying towers are perforated plates and air distribution ducts, but both have their own limitations. 1. Perforated plate distributors: such as the "A Novel Spray Drying Tower" (publication number CN201025426Y) and the "A Hot Air Distribution Device" (publication number CN203861941U), which homogenize airflow by setting single or multiple layers of distribution plates with vertical openings in the air inlet cone section. The main drawbacks of this type of technology are: (a) the perforated plate itself has high ventilation resistance, resulting in high system energy consumption; (b) for large towers, the flatness of the perforated plate and the parallelism between multiple layers are difficult to guarantee during processing and installation, which can easily lead to airflow deviation and affect the uniform airflow effect; (c) after the airflow diffuses through the discrete small holes, it is difficult to form a concentrated, high-speed air column at the spray gun nozzle, and the heat and mass exchange efficiency needs to be improved; (d) the high-temperature area at the bottom of the distributor lacks heat insulation measures, and heat-sensitive or sticky materials are prone to adhesion and deformation.

[0005] 2. A combination of baffles and distribution plates in the distributor: For example, the patent CN116407854B, "A hot air distribution device and spray drying tower and its application," uses a combination of baffles, distribution plates, and a distribution plate with inclined through holes to balance airflow uniformity and concentration. However, its structure is complex, requiring extremely high precision in the machining and verticality of the multiple perforated plates, making implementation difficult. Similarly, it lacks cooling protection at the bottom, posing a risk of airflow sticking to the walls. Furthermore, in multi-spray-gun layouts, this patent does not specifically address the uneven airflow caused by differences in the distance of each spray gun from the air inlet.

[0006] 3. Distributor type: such as the "Pressure Spray Drying Tower" with publication number CN201476502U, which adopts a structure with a central air distribution chamber and multiple vertical air distribution ducts evenly distributed around the periphery. Its main problems are: (a) Each distribution duct receives air axially from the top of the central air distribution chamber. Due to the different radii of the ducts from the central air inlet, there are differences in fluid resistance, which can easily lead to "airflow short-circuiting" in the ducts near the center, while the air volume in the edge ducts is insufficient, resulting in poor consistency of operating conditions for each spray gun; (b) The spray guns are directly exposed to the high-temperature hot air in the air distribution chamber, which may cause the liquid material inside the gun to be heated prematurely, affecting product quality; (c) The tower top structure also does not consider cooling protection for heat-sensitive areas.

[0007] 4. L-shaped hot air box: As disclosed in CN110332794B, "A hygienic low-resistance L-shaped hot air box" uses an L-shaped air duct with baffles, a compression section, and guide plates to reduce air resistance and improve airflow rectification. However, its structural design concentrates multiple spray guns at a single outlet of the central hot air duct, which not only limits the number of spray guns and their layout space, but also makes the dense droplet cloud prone to particle collision and agglomeration, making it unsuitable for products requiring the preparation of fine, uniform particles. In addition, its single L-shaped inlet lacks pretreatment of the uneven upstream flow, making it difficult to ensure the circumferential uniformity of the airflow before entering the drying chamber.

[0008] In summary, existing technologies struggle to simultaneously address key issues in the hot air distribution of multi-gun spray drying towers, such as uniform airflow distribution among the spray guns, system flow resistance, preventing sticking to the tower top, and flexibility in spray gun layout. Summary of the Invention

[0009] The purpose of this invention is to provide a hot air distributor for a multi-gun spray drying tower to solve the following problems existing in the prior art: First, uneven distribution of hot air from multiple spray guns leads to poor consistency in drying effect among the spray guns; second, the hot air distributor has high ventilation resistance, resulting in high system energy consumption; third, the high temperature area at the bottom of the distributor easily causes material adhesion and coking, affecting product quality and operational safety; fourth, the layout of the spray guns is limited, making it difficult to flexibly expand according to production capacity requirements, and the droplets from multiple guns are prone to mutual interference.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: A hot air distributor for a multi-gun spray drying tower, installed at the top of the drying tower, includes: The L-shaped air duct has its outlet end connected to the center of the top cover of the hot air distribution chamber; The hot air distribution chamber is enclosed by the hot air distribution chamber top cover, the hot air distribution chamber walls and the air insulation layer below, and the hot air distribution chamber is equipped with multiple spray gun air distribution tubes; Multiple spray gun air distribution tubes are evenly distributed circumferentially in the hot air distribution chamber. The inlet of each spray gun air distribution tube is connected to the hot air distribution chamber, and its outlet passes downward through the air insulation layer and leads to the interior of the drying tower. The number of spray guns corresponds to the number of spray gun distribution ducts. Each spray gun is coaxially inserted into the corresponding spray gun distribution duct, and its nozzle extends into the interior of the drying tower.

[0011] Furthermore, the L-shaped air duct includes, in sequence along the airflow direction, a rectifier, a horizontal straight section, a bent section with a baffle plate, a contracting rectifier cone section, and a lower straight section.

[0012] Furthermore, the spray gun air distribution tube has a double-layer conical structure, with a first and second guide cone welded parts coaxially nested inside, which divides the internal space into a first air distribution tube channel and a second air distribution tube channel.

[0013] Furthermore, a first guide vane is provided at the inlet of the first flow channel of the air distribution duct, and a second guide vane is provided at the inlet of the second flow channel of the air distribution duct.

[0014] Furthermore, both the first guide vane and the second guide vane are composed of multiple blades evenly distributed radially.

[0015] Furthermore, the air insulation layer is a hollow annular sandwich structure with an air distribution pipe through which the spray gun air distribution pipe passes. The air insulation layer is also connected to a cold air main pipe for introducing cooling air.

[0016] Furthermore, each of the air distribution pipes is surrounded by a cold air distribution triangular ring at its lower outer periphery. The cross-section of the cold air distribution triangular ring is a right triangle, and multiple cold air outlet holes are evenly distributed around the right-angled base of the cold air distribution triangular ring.

[0017] Furthermore, the inlet of the cold air distribution triangular ring is connected to the cold air main pipe through a cold air branch pipe.

[0018] Furthermore, a partition ring is provided between the right-angle vertex and the midpoint of the hypotenuse of the cross-section of the cold air distribution triangular ring, the space between the partition ring and the right-angle base is a cold air distribution cavity, and the space between the partition ring and the outer wall of the air distribution duct pipe is an air insulation cavity.

[0019] Furthermore, the spray gun is a single-fluid pressure spray gun or a dual-fluid spray gun.

[0020] Furthermore, the multiple spray gun air distribution tubes are evenly distributed in single or multiple rings within the hot air distribution chamber.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention include at least the following: 1. High airflow uniformity: Through the synergistic effect of the rectifier, baffle plate and converging rectifier cone in the L-shaped air duct, the upstream flow can be effectively smoothed, large-scale eddies can be eliminated, and a uniform vertical airflow into the room can be formed, laying the foundation for the uniform distribution of multiple spray guns in the future.

[0022] 2. Solve the problem of uneven airflow in spray guns and ensure product consistency: Adopt a radial blade double-layer air inlet cone structure to make hot air enter each spray gun air distribution tube evenly in the circumferential direction, eliminate the "short-circuit effect" caused by the difference in air inlet distance in the traditional axial air inlet method, and ensure that each spray gun receives hot air with a highly consistent flow rate and velocity.

[0023] 3. Improved drying efficiency: The double-layered guide channel and tapered conical structure inside the spray gun's air duct guide the radial airflow to the center and accelerate it, forming a concentrated, vertically downward high-speed air column that can tightly wrap the atomized material mist in the spray gun, enhancing the heat and mass transfer process.

[0024] 4. Solve the problem of material sticking to the wall and coking, and ensure safe operation: The air insulation layer and the cooling air circulating inside it form an active heat insulation barrier. On the one hand, it forms a protective air curtain at the outlet of the spray gun air duct to prevent material from returning to the top. On the other hand, it reduces the temperature of the bottom wall of the distributor, effectively avoiding the sticking and coking of heat-sensitive materials.

[0025] 5. Solve the problems of limited spray gun layout and droplet interference: The spray gun adopts a circumferentially distributed layout, which can be arranged in single or multiple rings according to production capacity requirements to avoid mutual interference of droplets; the spray gun air distribution tube adopts a modular and detachable structure, which facilitates maintenance and replacement and reduces downtime. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit the present invention. Wherein: Figure 1 This is a front view of one embodiment of the present invention; Figure 2 for Figure 1 Top view; Figure 3 This is an isometric view of the L-shaped airflow duct in this invention; Figure 4 This is an isometric view of the spray gun air distribution tube in this invention; Figure 5 This is a cross-sectional view of the spray gun air distribution tube in this invention; Figure 6 A three-dimensional diagram of the airflow path of a hot air distributor for a multi-spray-gun drying tower; Figure 7 Front view of the airflow path of the hot air distributor for a multi-nozzle drying tower; Figure 8 for Figure 1 A bottom view; Figure 9 This is a schematic diagram of the watershed for a traditional duct-type distributor; Figure 10 This is a schematic diagram of the flow area of ​​a hot air distributor for a multi-spray gun spray dryer. Figure 11 This is a flow velocity cloud map of a traditional duct-type distributor; Figure 12 Flow velocity cloud map of hot air distributor for spray drying with a multi-spray gun; Figure 13 for Figure 11 Flow velocity cloud map of a local area in the distribution duct of a traditional distribution duct type distributor; Figure 14 for Figure 12 Velocity cloud map of a local part of the air distribution tube of the spray gun in the hot air distributor of the spray gun spray dryer; Figure 15 Velocity contour plot of the cross-section of the hot air distribution chamber in a traditional duct-type distributor; Figure 16 This is a velocity contour plot of the cross-section of the hot air distribution chamber in a hot air distributor for multi-spray gun spray drying. Figure 17 for Figure 15 and Figure 16 Average velocity distribution curves of each branch ventilation duct section.

[0027] Reference numerals: 1. L-shaped airflow guide duct; 1a. Rectifier; 1b. Horizontal straight section; 1c. Airflow guide baffle; 1d. Contracting rectifier cone section; 1e. Lower straight section; 1f. Duct connection flange; 2. Hot air distribution chamber top cover; 2a. Spray gun mounting interface; 2b. Top cover upper plate; 2c. Top cover lower plate; 3. Walls of the hot air distribution chamber; 4. Air insulation layer; 4a. Main cold air duct; 4b. Branch cold air duct; 4c. Spreader duct connection; 4d. Cold air distribution triangular ring; 4e. Cold air outlet; 5. Spray gun air distribution duct; 5a. Air distribution duct top cover; 5b. Central duct; 5c. First guide vane; 5d. Second guide vane; 5e. First guide cone weldment; 5f. Second guide cone weldment; 5g. Air distribution duct duct connecting flange; 5h. First flow channel of air distribution duct; 5i. Second flow channel of air distribution duct; 6. Spray gun; 7. Hot air distribution chamber; A. Main hot air flow path. Detailed Implementation

[0028] To make the technical means, creative features, objectives, and effects of this invention easier to understand, the invention is further described below with reference to specific illustrations. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0030] like Figures 1 to 8 As shown in the figure, the hot air distributor for a multi-gun spray drying tower provided in this embodiment is installed on the top of the drying tower body. Its main components include: L-shaped guide air duct 1, hot air distribution chamber top cover 2, hot air distribution chamber wall 3, air insulation layer 4, spray gun air distribution tube 5, and spray gun 6.

[0031] like Figure 1 , Figure 3 As shown, the L-shaped guide duct 1 is installed at the center of the top cover 2 of the hot air distribution chamber via a duct connecting flange 1f. A flow rectifier 1a is installed at the inlet end of the L-shaped guide duct 1 via a flange, and the flow rectifier 1a contains a perforated plate. The horizontal straight section 1b is connected to the flow rectifier 1a via a flange. A flow guide baffle 1c is welded to the bend of the L-shaped guide duct 1, and the cross-section of the flow guide baffle 1c forms a 45° angle with the axis of the horizontal straight section 1b. In this embodiment, the flow guide baffle 1c has multiple parallel, downward-bending arc plates for guiding the flow, with each arc plate having a central angle of 90°. The flow guide baffle 1c has a downward-facing vertical section, the axis of which forms a 90° angle with the axis of the horizontal straight section 1b. The vertical section is connected to a reduced-diameter rectifier cone section 1d below the vertical section, and a lower straight section 1e is connected to the lower straight section 1e. The lower end of the lower straight section 1e is connected to a duct connecting flange 1f. The outer periphery of the L-shaped guide duct 1 is entirely wrapped with an insulation layer to reduce heat loss and ensure a stable temperature of the hot air entering the hot air distribution chamber.

[0032] like Figure 1 , Figure 2 As shown, the top cover 2 of the hot air distribution chamber is a ring-shaped sandwich structure with a central inner hole that matches the connecting flange 1f of the air duct. The top cover 2 is installed entirely above the wall 3 of the hot air distribution chamber. Multiple spray gun mounting interfaces 2a are welded onto the upper plate 2b of the top cover, and these interfaces are evenly distributed in single or multiple rings. Insulation material is laid between the upper plate 2b and the lower plate 2c of the top cover. The outer periphery of the lower plate 2c slopes downward, forming a conical dome structure above the wall 3 of the hot air distribution chamber.

[0033] like Figure 1As shown, the wall 3 of the hot air distribution chamber is a thin-walled cylindrical structure, with the top cover 2 of the hot air distribution chamber coaxially installed above it and the air insulation layer 4 coaxially installed below it. The outer perimeter of the wall 3 of the hot air distribution chamber is covered with an insulation layer.

[0034] like Figure 1 , Figure 8 As shown, the air insulation layer 4 is a ring-shaped sandwich structure, with multiple vertically penetrating air distribution pipes 4c between its top and bottom walls. The air distribution pipes 4c in the air insulation layer 4 are coaxially arranged and correspond one-to-one with the spray gun mounting interfaces 2a on the top cover 2 of the hot air distribution chamber, also evenly distributed in single or multiple loops. A cold air main duct 4a is connected to the lower part of the side wall circumference of the air insulation layer 4 for introducing protective cold air. The inner port of the cold air main duct 4a branches to connect to multiple cold air branch ducts 4b, and the outlet of each cold air branch duct 4b is connected to the side wall inlet of the cold air distribution triangular ring 4d. The cold air distribution triangular ring 4d surrounds the lower outer circumference of the corresponding air distribution pipe 4c. The cross-section of each cold air distribution triangular ring 4d is a right-angled triangle, and multiple cold air outlet holes 4e are evenly distributed circumferentially on the right-angled base of the cold air distribution triangular ring 4d. An insulation layer is laid on the outer periphery of the air insulation layer 4.

[0035] like Figure 7 As shown, a partition ring is provided between the right-angle vertex and the midpoint of the hypotenuse of the cross-section of the cold air distribution triangular ring 4d. The space between the partition ring and the right-angle base is the cold air distribution cavity. The space between the partition ring and the outer wall of the air distribution pipe 4c, i.e. the right-angle vertical side, is the air insulation cavity, which prevents the cold air from cooling the bottom outer wall of the air distribution pipe 4c.

[0036] like Figure 1 , Figure 4 , Figure 5 As shown, the spray gun distribution duct 5 has a double-layer conical structure. Multiple spray gun distribution ducts 5 are installed above the top wall of the air insulation layer 4, and are coaxially arranged and correspond one-to-one with the distribution duct pipe 4c and the spray gun mounting interface 2a, distributed in single or multiple rings. The upper end of the spray gun distribution duct 5 is the distribution duct top cover 5a, and a circular hole is opened in the center of the distribution duct top cover 5a. A central guide tube 5b is welded in the circular hole. The lower end of the distribution duct top cover 5a is equipped with a first guide vane 5c. Below the first guide vane 5c is a first guide cone weldment 5e. The center of the first guide cone weldment 5e is a first conical air duct that is wider at the top and narrower at the bottom. An annular first guide cone flat flange is welded to the outer periphery of the upper port of the first conical air duct. The first guide vane 5c is distributed on the circumference between the first guide cone flat flange and the distribution duct top cover 5a. The top cover 5a of the air distribution duct, the first guide vane 5c, and the interior of the first guide cone weldment 5e together constitute the first flow channel 5h of the air distribution duct 5 of the spray gun air distribution duct 5. Hot air enters through the spaces between the blades of the first guide vane 5c, then turns downwards, flowing downwards from the annular space between the first conical air duct of the first guide cone weldment 5e and the central duct 5b.

[0037] The center of the second guide cone weldment 5f is a second conical air duct, wider at the top and narrower at the bottom. An annular second guide cone flat flange is welded to the outer periphery of the upper end of the second conical air duct. The second conical air duct is coaxially fitted around the outer periphery of the first conical air duct, with the second guide cone flat flange located below the first guide cone flat flange. Second guide vanes 5d are distributed on the circumference between the first and second guide cone flat flanges. A branch duct connecting flange 5g is welded to the lower end of the second conical air duct of the second guide cone weldment 5f. The interiors of the first guide cone weldment 5e, the second guide vanes 5d, and the second guide cone weldment 5f together constitute the second flow channel 5i of the branch duct. Hot air enters through the spaces between the blades of the second guide vanes 5d, then turns downwards, flowing downwards from the annular space between the second and first conical air ducts.

[0038] In this embodiment, the first guide vane 5c and the second guide vane 5d have the same structure, both adopting a radially distributed multi-blade arrangement. The top cover 5a of the air distribution duct, the first guide vane 5c, the second guide vane 5d, the first guide cone weldment 5e, and the second guide cone weldment 5f are provided with corresponding mounting holes and are assembled by long studs.

[0039] like Figure 1 As shown, the spray gun 6 is installed in the spray gun mounting interface 2a of the hot air distribution chamber top cover 2 at the top of the drying tower. After passing through the spray gun mounting interface 2a, the spray gun 6 is coaxially inserted into the central duct 5b of the spray gun distribution duct 5, and then coaxially passes through the distribution duct pipe 4c in the air insulation layer 4, finally entering the interior of the drying tower. The spray gun 6 can be a single-fluid pressure spray gun or a dual-fluid spray gun.

[0040] The hot air distribution chamber 7 is an annular cavity structure. Its upper part is the hot air distribution chamber top cover 2, its side wall is the hot air distribution chamber wall 3, and its lower part is the air insulation layer 4. The hot air distribution chamber 7 is evenly arranged with single or multiple rings of spray gun air distribution tubes 5.

[0041] The working process of this embodiment is as follows: High-temperature drying hot air enters the L-shaped guide duct 1 along path A. After being rectified by the rectifier 1a, guided by the guide baffle 1c, and accelerated by the contraction and rectification cone section 1d, it forms a uniform, vertically downward high-quality airflow that enters the hot air distribution chamber 7 from the center. This airflow diffuses radially in all directions within the hot air distribution chamber 7, evenly reaching the periphery of the multiple spray gun distribution ducts 5 that are evenly distributed in single or multiple rings within the hot air distribution chamber 7.

[0042] Figure 9 This is a schematic diagram of the watershed for a traditional duct-type distributor. Figure 10 This is a schematic diagram of the flow area of ​​a hot air distributor for a multi-spray gun spray dryer. (Comparison) Figure 11 , Figure 12It can be observed that the L-shaped guide duct 1 effectively suppresses air wall separation and rotating vortex at the turning point, and the contraction cone section 1d further rectifies the flow, improving the velocity uniformity of the flow cross section. The hot air distribution chamber 7 obtains a vertically downward initial flow field, providing each spray gun air distribution duct 5 with a highly consistent initial inlet airflow in terms of flow rate and velocity, thus ensuring the consistency of the initial flow distribution of each spray gun.

[0043] contrast Figure 13 , Figure 14 It can be observed that in traditional duct-type distributors, each duct is sensitive to the direction of the initial inlet airflow. Because each duct cannot obtain a completely axial inlet airflow, the deflection of the inlet airflow leads to deflection of the airflow within the duct, resulting in the hot air failing to symmetrically envelop the spray gun spray, ultimately leading to uneven product drying. The hot air distributor for multi-gun spray drying towers in this invention effectively overcomes the fluctuation of the inlet airflow in its spray gun duct 5, achieving a flow perpendicular to the axis and with uniform cross-sectional velocity at the outlet of the spray gun duct 5, effectively ensuring the drying quality of the subsequent products.

[0044] For each spray gun air distribution duct 5, the first guide vane 5c and the second guide vane 5d force the airflow to enter the first flow channel 5h and the second flow channel 5i of the air distribution duct 5 in a uniform circumferential direction, ensuring the uniformity of the airflow in the entire circumferential direction, and thus ensuring the uniformity of the cross-sectional velocity. The first flow channel 5h and the second flow channel 5i forcibly divide the flow section of the air distribution duct into inner and outer rings, suppressing and blocking the lateral secondary flow and development on its flow section caused by the fluctuation of the airflow at the inlet of the spray gun air distribution duct 5. Under the further guidance of the first guide cone weldment 5e and the second guide cone weldment 5f, the gradually narrowing flow channel formed by the conical air duct accelerates the airflow and further reduces the circumferential velocity difference of the airflow. At the outlet of the first guide cone weldment 5e, the two rectified airflows converge towards the center and gradually eliminate the axial velocity difference during the downward acceleration process, finally merging at the bottom outlet of the spray gun air distribution duct 5 to form a vertically downward high-speed concentrated air column. Ultimately, this ensured the verticality of the air outlet of the spray gun's air distribution tube 5 and its uniformity across the air outlet cross section.

[0045] contrast Figures 15 to 17It can be observed that in traditional duct-type distributors, the duct inlet is directly exposed to the inlet airflow of the hot air distribution chamber. The flow velocity at the cross-section of the duct near the inlet is high, while the flow velocity at the cross-section of the duct farther from the inlet is low. Furthermore, due to the skewed airflow at the inlet of the hot air distribution chamber, the flow distribution of the axially uniformly arranged ducts is uneven and varies greatly. The airflow within each duct is severely skewed due to the duct inlet form. The hot air distributor for the multi-gun spray drying tower in this invention obtains a vertical, unskewed airflow at the inlet of the hot air distribution chamber. After entering the hot air distribution chamber 7, the airflow diffuses evenly in all directions. The airflow at the inlet of the spray gun duct 5 is constrained and guided by the first guide vane 5c and the second guide vane 5d, entering the spray gun duct evenly. Under the guidance of the first guide cone weldment 5e and the second guide cone weldment 5f, a vertically uniform high-speed airflow is formed. The flow rates of the inner and outer rings of the spray gun duct 5 are basically the same, and the flow across the cross-section of each spray gun duct 5 is uniform.

[0046] The spray gun 6 installed in the spray gun mounting interface 2a has its nozzle spraying material mist that is instantly enveloped and dried by the high-speed vertical air column.

[0047] Meanwhile, the flow path of the ambient temperature protective cold air is as follows: the protective cold air first enters from the main cold air duct 4a, passes through each cold air branch duct 4b to reach the interior of the cold air distribution triangular ring 4d at the lower end of each spray gun air distribution duct 5, and then is sprayed out from the evenly distributed cold air outlets 4e at the lower end of the cold air distribution triangular ring 4d, forming a ring-shaped protective air curtain at the outlet of the spray gun air distribution duct 5, effectively preventing the dried material from returning to the top and causing over-drying. At the same time, the air insulation layer 4 effectively isolates the high-temperature hot air in the hot air distribution chamber 7, keeping the wall temperature of the bottom wall of the air insulation layer 4 (i.e., the top of the inner chamber of the drying tower) at a low level, thereby preventing heat-sensitive materials from sticking and coking here.

[0048] In summary, this embodiment achieves efficient, uniform, and anti-sticking hot air distribution from multiple spray guns through a combination design of an L-shaped air duct, a double-layer spray gun distribution duct, and an air insulation layer with a cooling air curtain. This effectively solves the problems of uneven hot air distribution, high energy consumption, material sticking to the wall, and limited layout mentioned in the background art.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A hot air distributor for a multi-gun spray drying tower, installed on the top of the drying tower body, characterized in that, include: The L-shaped air duct (1) has its outlet end connected to the center of the top cover (2) of the hot air distribution chamber; The hot air distribution chamber (7) is formed by the hot air distribution chamber top cover (2), the hot air distribution chamber wall (3) and the air insulation layer (4) below. The hot air distribution chamber (7) is equipped with multiple spray gun air distribution tubes (5). Multiple spray gun air distribution tubes (5) are evenly distributed in the hot air distribution chamber (7) along the circumference. The inlet of each spray gun air distribution tube (5) is connected to the hot air distribution chamber (7), and its outlet passes downward through the air insulation layer (4) and leads to the interior of the drying tower. The number of spray guns (6) corresponds to the number of spray gun distribution ducts (5). Each spray gun (6) is coaxially inserted into the corresponding spray gun distribution duct (5), and its nozzle extends into the interior of the drying tower.

2. The hot air distributor for a multi-gun spray drying tower according to claim 1, characterized in that: The L-shaped air duct (1) includes, in sequence along the airflow direction, a rectifier (1a), a horizontal straight section (1b), a bent section with a guide baffle (1c), a contraction rectifier cone section (1d), and a lower straight section (1e).

3. The hot air distributor for a multi-gun spray drying tower according to claim 1, characterized in that: The spray gun air distribution tube (5) is a double-layer conical tube structure. Inside it are a first guide cone weldment (5e) and a second guide cone weldment (5f) that are coaxially nested, which divide the space inside the tube into the first air distribution tube channel (5h) and the second air distribution tube channel (5i).

4. The hot air distributor for a multi-gun spray drying tower according to claim 3, characterized in that, The first flow channel (5h) of the air distribution duct is provided with a first guide vane (5c) at its inlet, and the second flow channel (5i) of the air distribution duct is provided with a second guide vane (5d) at its inlet.

5. The hot air distributor for a multi-gun spray drying tower according to claim 4, characterized in that, Both the first guide vane (5c) and the second guide vane (5d) are composed of multiple blades evenly distributed radially.

6. The hot air distributor for a multi-gun spray drying tower according to claim 1, characterized in that, The air insulation layer (4) is a hollow annular sandwich structure with an air distribution pipe (4c) through which the spray gun air distribution pipe (5) passes. The air insulation layer (4) is also connected to a cold air main pipe (4a) for introducing cooling air.

7. The hot air distributor for a multi-gun spray drying tower according to claim 6, characterized in that, Each of the aforementioned air distribution pipes (4c) has a cold air distribution triangular ring (4d) surrounding its lower outer perimeter. The cross-section of the cold air distribution triangular ring (4d) is a right triangle, and multiple cold air outlet holes (4e) are evenly distributed around the right-angled base of the cold air distribution triangular ring (4d).

8. The hot air distributor for a multi-gun spray drying tower according to claim 7, characterized in that, The inlet of the cold air distribution triangular ring (4d) is connected to the cold air main pipe (4a) through a cold air branch pipe (4b).

9. The hot air distributor for a multi-gun spray drying tower according to claim 8, characterized in that, The cross-section of the cold air distribution triangular ring (4d) has a partition ring between the right-angle vertex and the midpoint of the hypotenuse. The partition ring and the right-angle base form a cold air distribution cavity, and the partition ring and the outer wall of the air distribution pipe (4c) form an air insulation cavity.

10. The hot air distributor for a multi-gun spray drying tower according to claim 1, characterized in that, The spray gun (6) is a single-fluid pressure spray gun or a dual-fluid spray gun.

11. The hot air distributor for a multi-gun spray drying tower according to claim 1, characterized in that, Multiple spray gun air distribution tubes (5) are evenly distributed in single or multiple rings within the hot air distribution chamber (7).

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