Hot air distributor for spray drying

Abstract

The utility model discloses a hot air distributor for spray drying, which is characterized in that the upper end of a circular shell is covered with a top cover, the side wall of the upper part of the circular shell is connected with a hot air inlet, the center of an inner cavity of the circular shell is provided with a baffling air cylinder, the upper end opening of the baffling air cylinder is propped against the lower part of the top cover, and the lower end opening of the baffling air cylinder is supported on a bottom partition plate; the upper portion of the baffling air cylinder is a closed cylinder body, and a plurality of ventilation holes are evenly distributed in the lower portion of the baffling air cylinder. A central air pipe is arranged in an inner cavity of the baffling air cylinder, an upper port of the central air pipe is located in the closed section of the baffling air cylinder, and a lower port of the central air pipe penetrates through the center of the bottom partition plate. A middle partition plate is arranged on the periphery of the middle of the baffling air cylinder, and a plurality of air distributing cylinders are evenly arranged along the circumference of the middle partition plate. A feed liquid spray gun is mounted in the center of the top cover; the lower end of the feed liquid spray gun extends along the axis of the central air duct; and a muzzle is positioned in the center of the lower port of the central air duct. Hot air is concentrated and uniformly distributed around feed liquid, the contact speed of materials and the hot air is increased, and the drying efficiency is improved.

Description

Technical Field

[0001] This utility model relates to a spray drying tower, and more particularly to a hot air distributor for spray drying, which is suitable for spray drying of heat-sensitive materials and belongs to the technical field of hot air drying equipment. Background Technology

[0002] Spray drying technology is a technique that instantly dries liquid materials under the action of high-temperature gas by spraying. Its advantages include: short drying time, suitability for drying heat-sensitive materials, wide range of applications, good sealing properties, and low cost. After decades of development, spray drying technology has become relatively mature and is widely used in the production of dairy products, detergents, and other powder products across multiple industries, especially in the pharmaceutical and ceramics industries.

[0003] The hot air distributor is a core component of the spray drying tower and is mostly located at the top of the spray drying tower to ensure that the hot air entering the drying tower is evenly distributed. Currently, the commonly used hot air distributors for spray drying towers are of two structural types: the duct type and the perforated plate type.

[0004] Air distributor of the type of air distribution tube: Chinese utility model patent with announcement number CN 209696309U discloses a hot air distributor for a horizontal flow drying tower, including a shell, a spray gun holder and an air regulating duct plate. The shell is cylindrical, with a mounting hole on the top end face, an air inlet on the side wall and an air outlet on the bottom end face. A baffle is provided inside the shell, surrounding the air outlet. The bottom end of the baffle is fixed to the edge of the air outlet. The top end of the spray gun holder is located in the mounting hole and connected to the top end of the shell, and the bottom end passes through the air outlet. The air regulating duct plate includes a partition and several air distribution tubes. The partition is located above the air inlet, with its outer side connected to the inner side wall of the shell and its inner side connected to the outer side wall of the baffle. The air distribution tubes pass through the partition, and the height of the bottom tube opening increases with the increase of the distance between it and the air inlet. The technical solution has the following drawbacks: 1. Because the air distribution duct uses a threaded or clamped fastening structure, there is a risk of the air distribution duct loosening. If it loosens, the axial position of the air distribution duct will shift, affecting the air distribution at that point, causing the central air duct to become misaligned, which in turn leads to uneven drying, tower wall adhesion, and other adverse results. 2. Because there is no protective gas device at the bottom of the hot air distributor, the risk of heat-sensitive materials adhering to the bottom of the hot air distributor cannot be avoided.

[0005] A perforated plate type air distributor: Chinese Patent Publication No. CN 112368060A discloses a gas disperser for guiding gas into a chamber, a spray drying apparatus including the gas disperser, and a method for regulating the gas flow in the gas disperser. The gas disperser includes: an inlet pipe section and a flow regulating device. The inlet pipe section has an upstream end and a downstream end, and has an inner diameter defining a cross-sectional area. The inlet section defines an axial direction, a radial direction, and a tangential direction. The flow regulating device is located in the inlet pipe section. The flow regulating device includes an orifice plate and flow straighteners. The flow straighteners are positioned substantially parallel to the orifice plate and axially spaced a certain distance from the downstream side of the orifice plate. The orifice plate has a predetermined orifice plate thickness in the axial direction, and each flow straightener has a predetermined flow straightener length in the axial direction, the flow straightener length being substantially greater than the orifice plate thickness. The technical solution has the following drawbacks: 1. It uses a perforated plate as the air distribution component. As is well known, perforated plates have high flow resistance. Multiple layers of perforated plates or a combination of a single layer and guide vanes will create significant flow resistance, requiring a large blower power to achieve the required air volume. 2. For large towers, the flatness of a single-layer perforated plate cannot be guaranteed. Poor flatness will cause the hot air passing through the perforated plate to be non-parallel to the axis, resulting in uneven drying and tower wall adhesion. Furthermore, the parallelism of multiple layers of perforated plates is also difficult to guarantee, adversely affecting processing and air distribution. 3. Because the hot air distributor lacks a protective gas device at the bottom, the risk of heat-sensitive materials adhering to the bottom of the hot air distributor cannot be avoided. Utility Model Content

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0007] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0008] The purpose of this invention is to overcome the problems existing in the prior art and provide a hot air distributor for spray drying, so as to achieve concentrated and uniform distribution of hot air around the liquid material, improve the contact speed between the material and the hot air, and improve the drying efficiency.

[0009] To solve the above technical problems, this utility model provides a hot air distributor for spray drying, comprising a circular shell, the upper end of which is covered with a top cover, a hot air inlet connected to the upper side wall of the circular shell, a baffle duct provided in the center of the inner cavity of the circular shell, the upper port of the baffle duct abutting against the bottom of the top cover, and the lower port of the baffle duct supported on a bottom partition plate, the outer periphery of which is connected to the lower inner wall of the circular shell; the upper part of the baffle duct is a closed cylinder, and the lower part of the baffle duct is uniformly distributed... Multiple ventilation holes are distributed throughout the structure; a central air duct is provided within the inner cavity of the baffle duct, with the upper end of the central air duct located in the closed section of the baffle duct and the lower end of the central air duct passing through the center of the bottom partition; a middle partition is provided between the outer periphery of the middle part of the baffle duct and the inner wall of the circular shell, and multiple through-flow air ducts are evenly arranged along the circumference of the middle partition; a spray gun seat is installed at the center of the top cover, and a liquid spray gun is fixed in the spray gun seat, with the lower end of the liquid spray gun extending along the axis of the central air duct and the nozzle located at the center of the lower end of the central air duct.

[0010] As an improvement to this utility model, the upper end of the central air duct is provided with a flared guide cone.

[0011] As a further improvement of this utility model, the outer periphery of each of the air distribution ducts is fixed to the middle partition plate by air distribution duct clamps.

[0012] As a further improvement of this utility model, each of the aforementioned air distribution ducts is provided with an enlarged diameter air distribution duct flange at its top.

[0013] As a further improvement of this utility model, the two sides of the hot air inlet are respectively tangent to the circular shell.

[0014] As a further improvement of this utility model, a protective air interlayer is provided below the bottom partition plate, and an interlayer bottom plate is provided below the protective air interlayer. A protective air inlet is provided on the lower side wall of the circular shell, which communicates with the protective air interlayer. Multiple protective air passages are evenly distributed on the interlayer bottom plate with the material spray gun axis as the center.

[0015] As a further improvement of this utility model, the sandwich base plate is a cone shape with a sunken center, and the center of the sandwich base plate is connected to the lower outer periphery of the central air duct.

[0016] As a further improvement of this utility model, the outer periphery of the circular shell, the top cover and the hot air inlet are respectively covered with a heat insulation layer.

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. A layer of baffle duct is added to the inner cavity of the circular shell. Hot air enters the annular space on the upper outer periphery of the baffle duct, and then flows downward evenly from each branch duct to the outer periphery where the ventilation holes are located. Then it enters the lower inner cavity of the baffle duct through the densely distributed ventilation holes, and then rises along the annular space between the central air duct and the baffle duct to the upper part of the central air duct. Then it bends and enters the inner cavity of the central air duct, ensuring that a uniform flow field of hot air is formed on the outer periphery of the liquid spray gun.

[0018] 2. The height of each branch duct can be adjusted independently via clamps, thereby adjusting the air volume and ensuring uniform air distribution in the outer annular space. Each branch duct is designed with a stepped flange at the top to prevent the branch duct from falling off.

[0019] 3. The lower circumference of the baffle duct is evenly and densely covered with multiple ventilation holes. The area of ​​the circumference where the ventilation holes are located can be larger than the cross-sectional area of ​​the circular shell, reducing wind resistance. Even if the baffle duct fails, it can still ensure good air distribution effect, and the air outlet is not deflected, thus ensuring product quality.

[0020] 4. The central air duct is installed in the center of the entire hot air distributor and is coaxial with the liquid spray gun. The upper part of the central air duct is designed with a guide cone structure, which can collect and rectify the airflow, further improving the uniformity and concentration of the airflow.

[0021] 5. Protective air is sprayed downwards from the lower outer periphery of the central air duct. When the liquid material and hot air are sprayed out at high speed from the lower end of the central air duct, it can avoid the formation of large vortices on its outer periphery.

[0022] 6. The overall structure is simple, the processing difficulty is low, the wind resistance of the distributor is low, and it is economical and energy-saving; the top of the distributor is designed with a top cover and flange connection, which makes it convenient to adjust and clean the entire distributor. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. 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 this utility model. Wherein:

[0024] Figure 1 This is a front view of the hot air distributor of this utility model;

[0025] Figure 2 for Figure 1 Top view;

[0026] Figure 3 for Figure 2 Sectional view along the middle AA;

[0027] Figure 4 for Figure 1 A sectional view along the middle edge BB;

[0028] In the diagram: 1. Top cover; 2. Circular shell; 2a. Protective air inlet; 3. Hot air inlet; 4. Baffle duct; 4a. Ventilation hole; 5. Bottom partition; 6. Protective air jacket; 6a. Jacket bottom plate; 7. Central air duct; 7a. Guide cone; 8. Middle partition; 9. Air distribution duct; 9a. Air distribution duct flange; 10. Air distribution duct clamp; 11. Spray gun holder; 12. Liquid spray gun. Detailed Implementation

[0029] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0030] To make the technical means, creative features, achieved objectives and effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0031] 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.

[0032] like Figures 1 to 4 As shown, the hot air distributor for spray drying of this utility model includes a top cover 1, a circular shell 2, a hot air inlet 3, a baffle duct 4, a bottom partition 5, a protective air jacket 6, a central air duct 7, a middle partition 8, a distribution duct 9, a distribution duct clamp 10, a spray gun base 11, and a liquid spray gun 12.

[0033] The top cover 1 covers the upper port of the circular shell 2 and is connected by a flange for easy disassembly and maintenance of the interior; the upper part of the top cover 1 is covered with an insulation layer. The outer periphery of the circular shell 2 is also covered with an insulation layer. A hot air inlet 3 is connected to the upper side wall of the circular shell 2. The hot air inlet 3 has a rectangular cross-section and is tangent to the circular shell 2 on both sides. The outer periphery of the hot air inlet 3 is covered with an insulation layer.

[0034] A spray gun holder 11 is installed at the center of the top cover 1. A downwardly extending liquid spray gun 12 is fixed in the spray gun holder 11. A baffle duct 4 is provided at the center of the inner cavity of the circular shell 2. The baffle duct 4 is coaxial with the circular shell 2, the central air duct 7 and the liquid spray gun 12. The upper end of the baffle duct 4 abuts against the bottom of the top cover 1, and the lower end of the baffle duct 4 is supported on the bottom partition 5. The outer periphery of the bottom partition 5 is welded or fixedly connected to the lower inner wall of the circular shell 2 in other ways.

[0035] The upper part of the baffle duct 4 is a closed cylinder, opposite to the hot air inlet 3; the lower part of the baffle duct 4 has multiple evenly distributed ventilation holes 4a. A central air duct 7 is provided inside the baffle duct 4, with its upper end located in the closed section of the baffle duct 4, and a flared guide cone 7a at the upper end of the central air duct. The lower part of the central air duct 7 is fixed to the bottom partition plate 5 by triangular stiffeners.

[0036] A partition plate 8 is provided between the outer periphery of the middle section of the baffle duct 4 and the inner wall of the circular shell 2. The partition plate 8 is located between the upper closed cylinder and the lower permeable section of the baffle duct 4. Multiple through-flow ducts 9 are evenly arranged along the circumference of the partition plate 8, usually more than six. The outer periphery of each duct 9 is fixed to the partition plate 8 by a duct clamp 10. Loosening the duct clamp 10 allows adjustment of the height of the duct 9, thereby adjusting the airflow. Each duct 9 has an enlarged diameter duct flange or flange at its top to prevent the duct 9 from falling off.

[0037] Below the bottom partition 5 is a protective air jacket 6, and below the protective air jacket 6 is a jacket bottom plate 6a. The lower side wall of the circular shell 2 has a protective air inlet 2a that communicates with the protective air jacket 6. Multiple protective air passages are evenly distributed on the jacket bottom plate with the axis of the liquid spray gun as the center. The jacket bottom plate is a cone shape with a sunken center. The lower end of the central air duct 7 passes through the center of the bottom partition 5, and the center of the jacket bottom plate is connected to the lower outer periphery of the central air duct 7. The lower end of the liquid spray gun 12 extends along the axis of the central air duct, and the nozzle is located at the center of the lower end of the central air duct.

[0038] During operation, high-temperature hot air enters the upper inner cavity of the circular shell 2 through the hot air inlet 3 on the side wall, is evenly distributed along the outer periphery of the baffle duct 4, then passes downward through each branch duct 9 into the annular space below the central partition plate 8, and then enters the inner cavity of the baffle duct 4 through each vent hole 4a, reaches the top of the central air duct 7, is rectified by the guide cone 7a and enters the central air duct 7, is concentrated and evenly distributed on the outer periphery of the liquid spray gun 12, and the liquid is sprayed out at high speed from the nozzle at the lower end of the liquid spray gun 12 and atomized, flows in the same direction as the hot air and evaporates and dries rapidly.

[0039] The characteristic of co-flow spray drying is that high-temperature air comes into contact with droplets with high moisture content. The surface temperature of the droplets is close to the wet-bulb temperature of the air. At the same time, as the moisture evaporates rapidly, the air temperature also drops rapidly. The dried product flows in parallel with the low-temperature air, so the material is not affected by high temperature throughout the process. It is particularly suitable for spray drying of heat-sensitive materials.

[0040] The high outlet velocity of the hot air distributor, according to the Venturi effect, causes a decrease in air pressure around the high-speed airflow, generating airflow vortices at the bottom of the distributor. This vortexes then engulf the wet material particles being dried in the airflow, causing adhesion and other problems. In this equipment, protective air enters the protective air jacket 6 through the protective air inlet 2a and then flows downwards through the air holes in the jacket bottom plate 6a. Using protective air with a temperature not lower than the dew point temperature of the dry hot air to purge the bottom of the hot air distributor effectively solves or alleviates the airflow vortices at the bottom of the distributor, thus resolving the material adhesion problem.

[0041] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A hot air distributor for spray drying, comprising a circular housing, the upper end of which is covered with a top cover, and a hot air inlet connected to the upper sidewall of the circular housing, characterized in that: The circular shell has a baffle duct at its center, with its upper end abutting against the bottom of the top cover and its lower end supported by a bottom partition. The outer periphery of the bottom partition is connected to the lower inner wall of the circular shell. The upper part of the baffle duct is a closed cylinder, and the lower part of the baffle duct has multiple evenly distributed ventilation holes. The inner cavity of the baffle duct has a central air duct, with its upper end located in the closed section of the baffle duct and its lower end passing through the center of the bottom partition. A middle partition is provided between the outer periphery of the middle part of the baffle duct and the inner wall of the circular shell, and multiple through-flow air ducts are evenly distributed along the circumference of the middle partition. A spray gun holder is installed at the center of the top cover, and a liquid spray gun is fixed in the spray gun holder. The lower end of the liquid spray gun extends along the axis of the central air duct, and the nozzle is located at the center of the lower end of the central air duct.

2. The hot air distributor for spray drying according to claim 1, characterized in that: The upper end of the central air duct is provided with a flared guide cone.

3. The hot air distributor for spray drying according to claim 1, characterized in that: The outer periphery of each of the aforementioned air distribution ducts is fixed to the central partition plate by air distribution duct clamps.

4. The hot air distributor for spray drying according to claim 1, characterized in that: Each of the aforementioned air distribution ducts has an enlarged diameter air distribution duct flange at its top.

5. The hot air distributor for spray drying according to claim 1, characterized in that: The hot air inlet is tangent to the circular shell on both sides.

6. The hot air distributor for spray drying according to claim 1, characterized in that: Below the bottom partition is a protective air interlayer, and below the protective air interlayer is an interlayer bottom plate. The lower side wall of the circular shell is provided with a protective air inlet that communicates with the protective air interlayer. Multiple protective air through holes are evenly distributed on the interlayer bottom plate with the material spray gun axis as the center.

7. The hot air distributor for spray drying according to claim 6, characterized in that: The sandwich base plate is a cone shape with a sunken center, and the center of the sandwich base plate is connected to the lower outer periphery of the central air duct.

8. The hot air distributor for spray drying according to any one of claims 1 to 7, characterized in that: The outer periphery of the circular shell, top cover, and hot air inlet is covered with an insulation layer.

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