A drying device that combines infrared radiation and hot air circulation

Abstract

This utility model discloses a drying device that combines infrared radiation and hot air circulation, comprising an inner cylinder, a stirring assembly, a hot air circulation assembly, a vacuum assembly, and an infrared heating layer. The hot air circulation assembly circulates and heats the material, while the vacuum assembly reduces the air pressure inside the inner cylinder, causing moisture to evaporate at a low temperature. The infrared heating layer penetrates and heats the material through radiation, and the stirring assembly promotes material flow. This solution addresses the problems of easy decomposition of heat-sensitive pharmaceutical intermediates, uneven drying, and high energy consumption in traditional drying technologies. The device is suitable for the production of pharmaceutical intermediates and offers advantages such as low-temperature activity protection, uniform drying, and energy saving.

Description

Technical Field

[0001] This utility model relates to the field of pharmaceutical processing equipment technology, and in particular to a drying device that combines infrared radiation and hot air circulation. Background Technology

[0002] Pharmaceutical intermediates are key intermediate products in the synthesis of chemical drugs, and their quality directly affects the purity, safety, and efficacy of the final drug. The drying process, as one of the core steps in the production of pharmaceutical intermediates, is crucial to the stability, solubility, and subsequent processing performance of the products. However, many pharmaceutical intermediates are heat-sensitive, easily oxidized, or easily decomposed fine chemicals (such as small molecule compounds containing amide bonds or ester groups). Traditional drying technologies have the following significant drawbacks in application: 1. Limitations of traditional hot air drying: Conventional hot air drying relies on convective heat transfer, with heat transferred from the material surface to the interior, resulting in low heat transfer efficiency and long drying times. Furthermore, the material surface is prone to overheating during drying (especially thick layers), leading to the decomposition or volatilization loss of active ingredients, making it difficult to meet the stringent requirements of "low-temperature drying" for pharmaceutical intermediates. 2. Efficiency bottlenecks of vacuum drying: Although vacuum drying can lower the boiling point of water by reducing air pressure (e.g., boiling at 50-60℃) and achieve low-temperature dehydration, it relies on the diffusion of water vapor on the material surface, resulting in slow drying rate and high energy consumption. Furthermore, for viscous or easily agglomerated intermediates (such as derivatives containing polysaccharides and proteins), uneven drying phenomena such as "surface crust and internal wet core" easily occur, affecting product quality consistency. 3. Insufficient synergy of existing equipment: Although some improved drying devices have introduced infrared radiation or stirring functions, each module operates independently (e.g., no linkage between radiation heating and convection heating, no feedback between temperature monitoring and process parameters), making it difficult to dynamically adjust the drying strategy according to the material state. At the same time, problems such as insufficient equipment sealing and poor material corrosion resistance easily lead to cross-contamination or material contamination, failing to meet the stringent cleanliness and sealing requirements of pharmaceutical GMP (Good Manufacturing Practice).

[0003] Therefore, there is an urgent need for a drying device that combines low-temperature uniformity, high efficiency and energy saving, and process controllability to meet the multiple requirements of "protecting active ingredients, improving drying quality, and complying with regulatory standards" in the production of pharmaceutical intermediates. Utility Model Content

[0004] The technical problem to be solved by this invention is to overcome the defects of the prior art and provide a drying device that combines infrared radiation and hot air circulation.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: This utility model discloses a drying device that combines infrared radiation and hot air circulation. The device comprises: a support cylinder; an inner cylinder, vertically and coaxially fixed inside the support cylinder; a stirring assembly, rotatably disposed inside the inner cylinder; a drive assembly, fixed to the top of the inner cylinder and connected to the stirring assembly; a hot air circulation assembly, communicating with the top of the inner cylinder; a vacuum assembly, communicating with the inner cylinder; a heating layer, surrounding the outer wall of the inner cylinder, heating the material in the drying chamber through infrared radiation; a heater, fixed inside the support cylinder and located below the inner cylinder, electrically connected to the heating layer; and a lid, detachably sealing the top of the inner cylinder, the lid having a feed inlet, a bearing seat, a first interface and a second interface communicating with the hot air circulation assembly, and a third interface communicating with the vacuum assembly. A first temperature sensor and a second temperature sensor are disposed on the side wall of the support cylinder, wherein the measuring end of the first temperature sensor extends into the inner cylinder to monitor the temperature of the material in the middle, and the bottom of the second temperature sensor extends below the inner cylinder to monitor the temperature of the heater.

[0006] As a preferred embodiment of this utility model, the hot air circulation assembly includes: an air inlet pipe, one end of which is connected to the inner cylinder through the first interface and extends to the bottom of the support cylinder; a return air pipe, one end of which is connected to the top of the inner cylinder through the second interface of the barrel cover; a heating module, fixed to the outer wall of the middle section of the air inlet pipe, for heating the air entering the inner cylinder; and a circulating fan, fixed to the outer wall of the middle section of the return air pipe, for driving the air circulation.

[0007] As a preferred embodiment of this utility model, the vacuum assembly includes: a vacuum tube, one end of which is connected to the inner cylinder through the third interface of the bucket lid; a vacuum generator, fixed at the lower outlet of the vacuum tube, for extracting gas from the inner cylinder to reduce the gas pressure; and a sealing structure, disposed at the connection between the third interface of the bucket lid and the vacuum tube, for ensuring the airtightness between the vacuum tube and the inner cylinder.

[0008] As a preferred embodiment of this utility model, the stirring assembly includes: a stirring shaft, which is vertically arranged along the axial direction of the inner cylinder and rotatably supported on the barrel cover at both ends by bearing seats of the barrel cover; and a stirring paddle, which has an annular structure and is distributed around the outer periphery of the stirring shaft in the circumferential direction, for pushing the material to flow radially along the inner cylinder.

[0009] As a preferred embodiment of this utility model, the driving assembly includes: a drive motor, fixed to one side of the top of the bucket lid, with its output end facing downwards; a transmission belt, sleeved on the output end of the drive motor; a driving wheel, fixed to the output shaft of the drive motor and meshing with one end of the transmission belt; and a driven wheel, fixed to the top of the stirring shaft and meshing with the other end of the transmission belt.

[0010] As a preferred technical solution of this utility model, an annular sealing groove is provided at the connection between the bucket lid and the inner cylinder, and a high-temperature resistant silicone rubber sealing ring is embedded in the annular sealing groove. The bucket lid is detachably connected to the top of the inner cylinder by at least two symmetrically arranged buckles to achieve a sealed cover.

[0011] As a preferred embodiment of this utility model, the heating module is an electric heating wire mesh, which is fixed to the outer wall of the air inlet pipe by a flange, and its heating power is adjustable.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. The device integrates a vacuum pumping component, which reduces the inner cylinder pressure (e.g., to -0.08 MPa) via a vacuum generator, lowering the boiling point of water to below 50°C. Combined with infrared radiation heating from the heating layer (wavelength matching the absorption peak of water molecules, with strong penetration), it can directly act on the moisture inside the material, accelerating molecular movement and evaporation. Simultaneously, the hot air circulation component replenishes surface heat through convection, preventing localized overheating. Under the synergistic effect of these two modes, the material is heated uniformly throughout, and the drying temperature is 20-30°C lower than traditional hot air drying, effectively preserving the active groups (such as acyl and hydroxyl groups) of pharmaceutical intermediates, thus improving product yield and purity. 2. The annular stirring paddle of the stirring assembly rotates at a uniform speed with the drive assembly, propelling the material radially along the inner cylinder, breaking up the accumulated layers and eliminating the "static zone." The airflow of the hot air circulation (driven by a circulating fan) and the heat from infrared radiation work together to form a dynamic balance of "flow-heating-evaporation," ensuring a small moisture gradient between the inside and outside of the material. Experiments have verified that this device improves the drying uniformity of viscous intermediates (such as aspirin intermediates containing more than 5% moisture) by 40% compared to traditional vacuum drying, and reduces the agglomeration rate from 15% to below 2%. 3. A first temperature sensor installed on the side wall of the support cylinder monitors the temperature of the material in the middle in real time, and a second temperature sensor monitors the surface temperature of the heater. After the data is fed back to the control system, the power of the heating module and the speed of the circulating fan can be dynamically adjusted to achieve precise control of the drying temperature within ±2℃. At the same time, the high-temperature resistant silicone rubber sealing ring and locking design of the lid ensure the airtightness of the inner cylinder under vacuum (-0.1MPa) or heating (≤120℃) conditions, avoiding external microorganisms and dust contamination, and meeting the strict requirements of pharmaceutical production for "sterile environment" and "no cross-contamination". 4. The hot air circulation component's air inlet duct reintroduces the dried, humid air (containing a small amount of water vapor) into the heating module, where it is reheated and reused, resulting in 30-40% energy savings compared to traditional direct-vent drying. Infrared radiation heating achieves a heat conversion efficiency of >85%, further reducing energy consumption. Furthermore, the modular design of the device (such as a removable lid and an easy-to-clean stirring paddle) facilitates cleaning and disinfection, meeting the pharmaceutical production standards of "easy cleaning and low residue," making it suitable for large-scale continuous production. Attached Figure Description

[0013] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is the front view of this utility model; Figure 3 This is a top view of the present invention; Figure 4 This is a cross-sectional structural schematic diagram of the present invention; In the diagram: 1. Support cylinder; 2. Inner cylinder; 3. Stirring assembly; 4. Drive assembly; 5. Hot air circulation assembly; 6. Vacuum assembly; 7. Heating layer; 8. Heater; 9. Bucket lid; 10. First temperature sensor; 11. Second temperature sensor; 31. Stirring shaft; 32. Stirring paddle; 41. Drive motor; 42. Transmission belt; 43. Drive wheel; 44. Driven wheel; 51. Air inlet pipe; 52. Air return pipe; 53. Heating module; 54. Circulating fan; 61. Vacuum pipe; 62. Vacuum generator; 63. Sealing structure; 91. Feed inlet; 92. Bearing seat; 93. First interface; 94. Second interface; 95. Third interface; 96. Annular sealing groove. Detailed Implementation

[0014] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0015] In the attached diagram, all identical reference numerals refer to the same components.

[0016] Example 1: Basic Co-drying Device like Figure 1-4As shown, the support cylinder 1 is a vertically arranged metal cylinder, with an inner cylinder 2 coaxially fixed inside. The top of the inner cylinder 2 is open and detachably sealed to the barrel cover 9. The barrel cover 9 has a feed inlet 91, and its edge is provided with an annular sealing groove 96 and a high-temperature resistant silicone rubber sealing ring is embedded. It is pressed and fixed to the top of the inner cylinder 2 by at least two symmetrical buckles to ensure the airtightness of the drying chamber.

[0017] Please see the appendix Figure 4 The stirring assembly 3 includes a stirring shaft 31 and an annular stirring paddle 32. The stirring shaft 31 is vertically arranged along the axial direction of the inner cylinder 2, with its lower end rotatably supported on the lid 9 via a bearing seat 92, and its upper end extending out of the lid 9. The annular stirring paddle 32 is evenly distributed around the stirring shaft 31, with its outer edge in clearance fit with the inner wall of the inner cylinder 2, used to drive the material radially. The drive assembly 4 is fixed to the top of the lid 9 and includes a drive motor 41, a transmission belt 42, a drive wheel 43, and a driven wheel 44. The output end of the drive motor 41 is arranged downwards, the drive wheel 43 is fixed to the output shaft of the drive motor 41, the driven wheel 44 is fixed to the top of the stirring shaft 31, and the transmission belt 42 is sleeved between the drive wheel 43 and the driven wheel 44 to realize the power transmission of the drive motor 41 to the stirring shaft 31.

[0018] Please see the appendix Figure 3 The hot air circulation assembly 5 includes an air inlet pipe 51, a return air pipe 52, a heating module 53, and a circulating fan 54. One end of the air inlet pipe 51 is connected to the first interface 93 and extends to the bottom of the support cylinder 1, while the other end is connected to the heating module 53. One end of the return air pipe 52 is connected to the second interface 94 (located at the top of the inner cylinder 2), while the other end is connected to the inlet of the circulating fan 54. The outlet of the circulating fan 54 is connected to the inlet of the heating module 53, forming a closed-loop circulation path of "inner cylinder 2 → return air pipe 52 → circulating fan 54 → heating module 53 → air inlet pipe 51 → inner cylinder 2". The heating module 53 is an electric heating wire mesh, fixed to the outer wall of the air inlet pipe 51 by a flange, and its power is adjustable. It is used to heat the circulating air.

[0019] The vacuum assembly 6 includes a vacuum tube 61, a vacuum generator 62, and a sealing structure 63: one end of the vacuum tube 61 is connected to the third interface 95 (the third interface 95 is located above the side wall of the inner cylinder 2), and the other end extends downward to the outside of the support cylinder 1 and is connected to the vacuum generator 62; the sealing structure 63 is an annular sealing gasket surrounding the third interface 95, sandwiched between the vacuum tube 61 and the lid 9, to ensure the airtightness of the inner cylinder 2 and the vacuum tube 61 during vacuuming.

[0020] The heating layer 7 is an infrared radiation coating surrounding the outer wall of the inner cylinder 2. It is electrically connected to the heater 8 inside the support cylinder 1 via a wire. The heater 8 is an adjustable power electric heater used to excite the heating layer 7 to emit infrared rays, directly heating the material inside the inner cylinder 2. A first temperature sensor 10 and a second temperature sensor 11 are provided on the side wall of the support cylinder 1: the temperature measuring end of the first temperature sensor 10 passes through the side wall of the support cylinder 1 and the side wall of the inner cylinder 2, extending into the middle region of the inner cylinder 2 to monitor the material temperature; the temperature measuring end of the second temperature sensor 11 is attached to the outer surface of the heater 8 to monitor the operating temperature of the heater 8.

[0021] Example 2: Drying apparatus with enhanced stirring The difference between this embodiment and Embodiment 1 lies in the improved structure of the stirring paddle 32 in the stirring assembly 3: the stirring paddle 32 adopts a helical blade structure, with three sets spaced circumferentially along the stirring shaft 31, and the rotation direction of each set of helical blades is opposite (adjacent sets are left-handed and right-handed, respectively). The transmission belt 42 of the drive assembly 4 is replaced with a synchronous belt, and the driving pulley 43 and driven pulley 44 adopt a synchronous belt pulley structure to avoid belt slippage and improve power transmission accuracy. The heating module 53 is replaced with a PTC ceramic heating element, which is linked with the heater 8 through a temperature control module and automatically adjusts the heating power according to the feedback signal of the first temperature sensor 10 to ensure that the hot air temperature is stable within the set range (e.g., 40-60℃).

[0022] Example 3: High-Sealing Drying Device This embodiment focuses on optimizing the sealing structure 63 of the vacuum assembly 6: the connection end between the vacuum tube 61 and the third interface 95 adopts a quick-release clamp structure, with a fluororubber sealing ring on the inner side of the clamp and bolts for tightening on the outer side, achieving quick disassembly and high-pressure sealing (capable of withstanding a vacuum of -0.1MPa). Aluminum silicate insulation cotton is filled between the inner cylinder 2 and the support cylinder 1 to reduce the loss of infrared radiation heat to the outside. The infrared radiation coating of the heating layer 7 uses a ceramic material doped with nano-iron oxide to enhance the absorption efficiency of moisture (wavelength concentrated at 2.5-3μm, matching the absorption peak of water molecule vibration). Both the first temperature sensor 10 and the second temperature sensor 11 use armored thermocouples, with the measuring end inserted into the inner cylinder 2 through a sealed joint to prevent material particles from clogging the temperature measuring channel.

[0023] In the above embodiments, the components work collaboratively through modular design: the hot air circulation component 5 circulates and heats the humid air, reducing energy consumption; the vacuum component 6 reduces the air pressure in the inner cylinder 2, allowing moisture to evaporate at low temperatures; the infrared radiation from the heating layer 7 penetrates the material, complementing the hot air convection heating; the stirring component 3 promotes material flow, preventing localized overheating or clumping; temperature sensors 10 and 11 provide real-time temperature data feedback, which, in conjunction with the power adjustment of the heater 8 and heating module 53, enables precise control of the drying process. The device is suitable for low-temperature drying of heat-sensitive materials such as pharmaceutical intermediates, balancing efficiency, uniformity, and activity protection.

[0024] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A drying apparatus that combines infrared radiation and hot air circulation, characterized in that, include: Support cylinder (1); inner cylinder (2), vertically and coaxially fixed inside the support cylinder (1); stirring assembly (3), rotatably disposed inside the inner cylinder (2); drive assembly (4), fixed to the top of the inner cylinder (2), and connected to the stirring assembly (3); hot air circulation assembly (5), connected to the top of the inner cylinder (2); vacuum assembly (6), connected to the inner cylinder (2); heating layer (7), surrounding and covering the outer wall of the inner cylinder (2), heating the material in the drying chamber through infrared radiation; heater (8), fixed inside the support cylinder (1) and located below the inner cylinder (2), electrically connected to the heating layer (7); bucket lid (9) The detachable sealing cover is attached to the top of the inner cylinder (2). The cover (9) is provided with a feed port (91), a bearing seat (92), a first interface (93) and a second interface (94) connected to the hot air circulation assembly (5), and a third interface (95) connected to the vacuum assembly (6). The side wall of the support cylinder (1) is provided with a first temperature sensor (10) and a second temperature sensor (11). The temperature measuring end of the first temperature sensor (10) extends into the inner cylinder (2) to monitor the temperature of the material in the middle. The bottom of the second temperature sensor (11) extends into the bottom of the inner cylinder (2) to monitor the temperature of the heater (8).

2. The drying apparatus for the coordinated use of infrared radiation and hot air circulation according to claim 1, characterized in that, The hot air circulation assembly (5) includes: an air inlet pipe (51), one end of which is connected to the inner cylinder (2) through the first interface (93) and extends to the bottom of the support cylinder (1); a return air pipe (52), one end of which is connected to the top of the inner cylinder (2) through the second interface (94); a heating module (53), which is fixed to the outer wall of the middle section of the air inlet pipe (51) for heating the air entering the inner cylinder (2); and a circulating fan (54), which is fixed to the outer wall of the middle section of the return air pipe (52) for driving the air circulation.

3. The drying apparatus for the coordinated use of infrared radiation and hot air circulation according to claim 1, characterized in that, The vacuum assembly (6) includes: a vacuum tube (61), one end of which is connected to the inner cylinder (2) through the third interface (95); a vacuum generator (62), fixed at the lower outlet of the vacuum tube (61), used to extract gas from the inner cylinder (2) to reduce the gas pressure; and a sealing structure (63), which is provided at the connection between the third interface (95) and the vacuum tube (61), used to ensure the airtightness between the vacuum tube (61) and the inner cylinder (2).

4. The drying apparatus for the coordinated use of infrared radiation and hot air circulation according to claim 1, characterized in that, The stirring assembly (3) includes: a stirring shaft (31), which is vertically arranged along the axial direction of the inner cylinder (2) and rotatably supported on the barrel cover (9) by the bearing seats (92) at both ends; and a stirring paddle (32), which is an annular structure and distributed around the outer periphery of the stirring shaft (31) in the circumferential direction, for pushing the material to flow radially along the inner cylinder (2).

5. A drying apparatus for the coordinated use of infrared radiation and hot air circulation according to claim 4, characterized in that, The drive assembly (4) includes: a drive motor (41) fixed to the top side of the bucket cover (9) with its output end facing downwards; a transmission belt (42) sleeved on the output end of the drive motor (41); a drive wheel (43) fixed on the output shaft of the drive motor (41) and meshing with one end of the transmission belt (42); and a driven wheel (44) fixed to the top of the stirring shaft (31) and meshing with the other end of the transmission belt (42).

6. The drying apparatus for the coordinated use of infrared radiation and hot air circulation according to claim 1, characterized in that, The connection between the lid (9) and the inner cylinder (2) is provided with an annular sealing groove (96). A high-temperature resistant silicone rubber sealing ring is embedded in the annular sealing groove (96). The lid (9) is detachably connected to the top of the inner cylinder (2) by at least two symmetrically arranged buckles to achieve a sealed cover.

7. A drying apparatus for the coordinated use of infrared radiation and hot air circulation according to claim 2, characterized in that, The heating module (53) is an electric heating wire mesh, which is fixed to the outer wall of the air inlet pipe (51) by a flange, and its heating power is adjustable.

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