Sublimation refining apparatus for purification of caffeine

Abstract

The application belongs to the technical field of caffeine purification, and discloses a sublimation refining device for caffeine purification, which comprises a rack, a sealed box arranged on the rack, a material disc cooperatively connected to the bottom of the sealed box, and a main motor for providing rotary power; the main motor is drivingly connected with a main shaft longitudinally penetrating through the sealed box. The heat-conducting oil in the oil storage pipe is heated by the built-in electric heating rod, and the heat is conducted to the heat exchange pipe to form an internal heating structure. The heat exchange pipe is inserted into the material, and the serpentine structure increases the effective heat exchange area. The mechanical mixing action of the material turning frame continuously breaks the temperature boundary layer inside the material. This internal dynamic heat transfer mechanism ensures that the material is heated in a uniform state, avoids the coking or sticking phenomenon caused by local overheating, improves the heat transfer efficiency, and makes the caffeine sublimate in a stable thermodynamic state, thereby improving the overall material utilization rate and sublimation quality.

Description

Technical Field

[0001] This invention belongs to the field of caffeine purification technology, specifically a sublimation refining device for caffeine purification. Background Technology

[0002] In existing technologies, caffeine extraction and purification typically employ sublimation, utilizing the physical property of caffeine that transforms directly from a solid to a gaseous state at a specific temperature without passing through a liquid phase, and then directly sublimates and crystallizes upon cooling. In conventional industrial production and laboratory preparation, the sublimation purification apparatus for caffeine purification mainly consists of a heating vessel at the bottom, a gas channel in the middle, and a condenser at the top. During operation, crude caffeine is dispersed at the bottom of the heating vessel, and the bottom is continuously heated by an external heat source, causing the caffeine to sublimate. The resulting gas naturally rises to the condenser and sublimates into highly pure caffeine crystals. Finally, the process is stopped for manual scraping and collection.

[0003] However, existing sublimation refining devices have significant drawbacks in terms of heating and airflow conduction. First, the traditional static bottom heating mode results in extremely uneven temperature distribution within the material. Material near the bottom is prone to coking or carbonization due to localized overheating, while the upper material receives insufficient heating, leading to low overall sublimation efficiency. Simultaneously, static heating easily causes severe adhesion of the material at high temperatures, reducing not only heat transfer efficiency but also material utilization. Second, the gas produced during sublimation rises primarily through natural convection within the device, resulting in a slow gas flow rate. This leads to excessively long residence time of the high-temperature gas in the heated zone, increasing the probability of side reactions. More seriously, the slow airflow is highly susceptible to sublimation and crystallization due to localized temperature drops when passing through the central baffle or channel gaps. Over time, these crystals accumulate and block the exhaust channels, creating dead zones in the airflow and severely affecting the continuous and stable operation of the device.

[0004] Furthermore, existing equipment also faces significant technical bottlenecks in the condensation and collection stages. Traditional condensation surfaces are mostly fixed, flat covers. After sublimation, caffeine deposits on these surfaces, gradually forming a thick crystalline layer. Due to the poor thermal conductivity of caffeine crystals, the thickening of the crystalline layer drastically increases thermal resistance, causing a sharp decline in condensation efficiency over time. Simultaneously, existing collection methods heavily rely on manual operation. The equipment must be shut down and the sealed chamber opened after the sublimation process is complete, and the crystals must be manually scraped off. This open-type unloading method is not only cumbersome and inefficient, failing to meet the demands of continuous production, but also easily generates fine dust during scraping, leading to the loss of high-value products and causing dust pollution to operators' health and the workshop environment. Summary of the Invention

[0005] The purpose of this invention is to provide a sublimation refining apparatus for caffeine purification, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a sublimation refining apparatus for caffeine purification, comprising a frame, a sealed box disposed on the frame, a material tray connected to the bottom of the sealed box, and a main motor providing rotational power;

[0007] The main motor drives a main shaft that runs longitudinally through the sealed box. The main shaft is connected from bottom to top to a material turning assembly that extends into the material tray, a gathering assembly located above the material tray, and a collection assembly located at the top of the sealed box.

[0008] The material turning assembly includes a heat exchange tube that rotates synchronously with the main shaft. The heat exchange tube is configured to extend into the material to provide an internal heat source, and the material turning assembly is configured to be driven by the main shaft to perform planetary mixing and stirring of the material around the heat exchange tube.

[0009] The converging assembly includes a fixed partition plate and a movable partition plate stacked on top of each other. Both the fixed partition plate and the movable partition plate are provided with multiple converging holes. The main shaft converts the rotational power into eccentric displacement through a transmission mechanism and drives the movable partition plate to slide horizontally eccentrically relative to the fixed partition plate, so that the converging holes on the two partition plates are periodically interleaved and conduct mechanical shearing and scraping of the pores.

[0010] The inner top wall of the sealed box is provided with a condensation component for the sublimation gas. The main shaft drives the collection component to rotate circumferentially against the bottom surface of the condensation component to scrape off and temporarily store the crystalline powder. The collection component is triggered by a mechanical structure at a specific phase of its circumferential rotation trajectory to discharge the material downwards.

[0011] As a further technical solution of the present invention, the material turning assembly further includes a sun gear fixedly sleeved with the main shaft, and a gear frame fixed to the bottom of the sealed box. A planetary gear is provided between the sun gear and the gear frame, which meshes with both of them. The bottom ends of the plurality of planetary gears are respectively coaxially connected to a material turning frame that extends into the inside of the material tray.

[0012] As a further technical solution of the present invention, the bottom end of the main shaft is connected to a mounting shaft located below the sun gear, and an oil storage pipe is fixedly sleeved inside the mounting shaft;

[0013] An electric heating rod is installed inside the oil storage pipe. The heat exchange tube is serpentine and fixedly connected to the bottom end of the oil storage pipe. The oil storage pipe and the heat exchange tube are filled with heat-conducting oil.

[0014] As a further technical solution of the present invention, the transmission mechanism for driving the movable partition includes a cam sleeved on the outer side of the main shaft;

[0015] The edge of the fixed partition is fixedly connected to the inner wall of the sealed box, and the movable partition is movably engaged in the sealed box and its vertical displacement is restricted.

[0016] The movable partition plate has a through hole in the middle to accommodate the cam. The cam rotates with the main shaft, thereby driving the movable partition plate to slide eccentrically.

[0017] The converging holes on both the fixed partition and the moving partition are inverted conical structures with the lower air inlet larger than the upper air outlet.

[0018] As a further technical solution of the present invention, the condensation assembly includes a cooling plate installed on the top wall of the sealed box, and the main shaft passes through the bottom surface of the cooling plate and is movably sleeved thereon.

[0019] The cooling plate has a cooling chamber inside for circulating cooling water to pass through. The cooling plate has an inlet and a drain on both sides that penetrate the outer wall of the sealed box and connect to the cooling chamber.

[0020] As a further technical solution of the present invention, the collecting component includes a mounting bracket fixedly sleeved on the main shaft, and a scraper is provided on one side of the mounting bracket, which is located directly below the cooling plate and whose top surface is in close contact with the bottom surface of the cooling plate.

[0021] The end of the scraper away from the mounting frame is connected to a downwardly extending extension frame, and a flexible collection box located directly below the scraper is installed on the inner side of the extension frame.

[0022] The bottom of the flexible collection box is inclined outward, and a discharge port is provided at the farthest end of the inclination.

[0023] As a further technical solution of the present invention, a vertical extension sleeve rod is movably sleeved inside the side wall of the extension frame, and the upper end of the extension sleeve rod is linked to the side of the flexible collection box through a connecting block.

[0024] A limiting spring is fitted onto the outer side of the extension sleeve. The upper end of the limiting spring abuts against the connecting block, and the lower end abuts against the inner bottom wall of the extension frame. The extension sleeve extends downward through the extension frame and is fixed with an abutment joint.

[0025] As a further technical solution of the present invention, an abutment ring fixed to the inner wall of the sealed box is provided directly below the collection component, and the bottom end of the abutment head abuts against the top surface of the abutment ring;

[0026] The abutting ring is a stepped ring, with the outer ring being higher than the inner ring. The top surface of the outer ring is partially recessed and has a groove. The inner ring has a through discharge port on the side corresponding to the groove. The bottom end of the discharge port is connected to a discharge pipe that extends out of the sealed box.

[0027] When the main shaft drives the abutment to rotate to the groove, the limiting spring restores its deformation and drives the flexible collection box to move downward as a whole, so that the discharge port and the discharge outlet are connected.

[0028] As a further technical solution of the present invention, the top of the sealing box is fixed with a mounting bracket for mounting the main motor, the inner walls of both sides of the frame are equipped with longitudinal guide rails, the lower end of the outer side of the sealing box is provided with a locking block, the sealing box is movably locked onto the longitudinal guide rail by the locking block, and the material tray is configured to slide up and down along the longitudinal guide rail to achieve disassembly and closure.

[0029] As a further technical solution of the present invention, the cooling plate is made of pure copper and its bottom surface is coated with a polytetrafluoroethylene anti-stick coating, the flexible collection box is made of pharmaceutical grade fluororubber, and a temperature sensor is installed in the internal patch of the material tray.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. This invention, through the coordinated operation of the material-turning assembly and the internal heat-conducting oil heating system, changes the traditional static bottom heating mode, achieving uniform heating and dynamic stirring of the material. This solves the problems of local overheating and high-temperature adhesion. Specifically, the main motor drives the main shaft to rotate, which in turn drives the sun gear at the bottom to rotate. The sun gear drives the planetary gears meshing with it to rotate within the gear carrier and revolve around the sun gear, thereby driving the bottom material-turning frame to perform planetary mixing and stirring within the material tray. Simultaneously, the system uses a serpentine heat exchange tube that penetrates deep into the material as a heat source. The built-in electric heating rod heats the heat-conducting oil in the oil storage pipe, and the heat is conducted to the heat exchange tube, forming an internal heating structure. The heat exchange tube is interspersed in the material, and its serpentine structure increases the effective heat exchange area. Combined with the mechanical mixing action of the material-turning frame, it continuously breaks down the internal temperature boundary layer of the material. This internal dynamic heat transfer mechanism ensures that the material is heated in a uniform state, avoiding charring or adhesion caused by local overheating, and improving heat transfer efficiency. The system allows caffeine to sublimate under stable thermodynamic conditions, improving the overall material utilization rate and sublimation quality.

[0032] 2. This invention, through the design of the converging component, transforms the rotational power of the main shaft into accelerated airflow guidance and a mechanical anti-clogging mechanism, ensuring unobstructed exhaust passages and efficient airflow guidance. This invention utilizes a fixed baffle and a moving baffle that slides eccentrically horizontally driven by a cam, stacked vertically to form an airflow converging structure. When the main shaft drives the cam to rotate, it drives the moving baffle to continuously slide eccentrically against the surface of the fixed baffle while limiting its vertical displacement. During this process, the inverted conical converging holes distributed circumferentially on the two baffles periodically intersect and overlap. The diameter of the inverted conical holes is set... The design generates a hydrodynamic guiding effect on the gas, accelerating the sublimated gas rising from the bottom as it passes through the baffle, allowing it to quickly escape from the lower heated zone and preventing side reactions caused by gas stagnation. At the same time, the eccentricity of the cam allows the solid edge of the moving baffle to cover and rub against the edge area of ​​the fixed baffle aperture during the periodic misalignment and sliding of the upper and lower baffles. This continuous mechanical shearing and scraping action removes the deposits that initially condense and crystallize at the edge of the pores, eliminating the potential for blockage inside the pipeline and ensuring the stability and exhaust efficiency of the purification unit under continuous operation.

[0033] 3. This invention achieves automation and airtightness of phase change heat exchange and product collection by combining a top condensation component with a purely mechanically linked automatic collection component. This solves the problems of traditional equipment requiring shutdown for cleaning and dust generation. The pure copper cooling plate at the top of the device has a cooling chamber inside and is connected to circulating cooling water externally, providing a stable sublimation interface for the rising caffeine gas. When the main shaft rotates, it simultaneously drives the scraper on the mounting frame to continuously scrape the bottom surface of the cooling plate in a circumferential manner, cleaning the freshly sublimated caffeine powder in real time, preventing the accumulation of crystal layer that would increase thermal resistance, and maintaining the heat exchange state of the condensation surface. The scraped-off powder falls into the flexible collection box below. The collection and discharging assembly forms a dynamic unloading mechanism through an extended sleeve, a limiting spring, an abutment joint, and a fixed abutment ring with a groove. During the normal rotation stroke, the limiting spring is compressed, and the discharge port is sealed by the solid part of the abutment ring, achieving temporary powder storage. When the abutment joint rotates to the groove position of the abutment ring, the spring releases its elastic force, pushing the collection box to sink, so that its discharge port aligns with the fixed discharge port at the bottom. The powder inside the box is then discharged outside the device. After passing the groove, the mechanism automatically resets and re-closes. This unloading process is completed periodically and automatically in a closed state, avoiding dust leakage and material loss, and improving continuous production efficiency and collection purity. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 This is a cross-sectional schematic diagram of the internal structure of the longitudinal guide rail of the present invention;

[0036] Figure 3 This is a cross-sectional schematic diagram of the internal structure of the sealing box of the present invention;

[0037] Figure 4 This is a separate schematic diagram of the material turning component structure of the present invention;

[0038] Figure 5 This is a partial cross-sectional view of the material turning assembly of the present invention;

[0039] Figure 6 This is an exploded view of the main shaft and converging component structure of the present invention;

[0040] Figure 7 This is a cross-sectional schematic diagram of the convergence component structure of the present invention;

[0041] Figure 8 This is a schematic diagram illustrating the cooperation between the condensation component and the collection component mechanism of the present invention;

[0042] Figure 9 This is a cross-sectional schematic diagram of the condenser assembly structure of the present invention;

[0043] Figure 10 This is a separate schematic diagram of the abutment ring structure of the present invention;

[0044] Figure 11 This is a cross-sectional schematic diagram of the component structure collected in this invention;

[0045] Figure 12 for Figure 11 An enlarged schematic diagram of the structure at point A in the middle.

[0046] In the diagram: 1. Frame; 2. Longitudinal guide rail; 3. Material tray; 4. Sealing box; 5. Fixing frame; 6. Main motor; 7. Main shaft; 8. Tilting assembly; 801. Sun gear; 802. Planetary gear; 803. Gear frame; 804. Tilting frame; 805. Mounting shaft; 806. Oil reservoir; 807. Heating rod; 808. Heat exchanger tube; 9. Abutment ring; 10. Groove; 11. Discharge port; 12. Discharge pipe; 13. Condensation unit Components; 131. Cooling plate; 132. Cooling chamber; 133. Water inlet; 134. Drain outlet; 14. Converging assembly; 141. Fixed partition; 142. Moving partition; 143. Converging hole; 144. Cam; 15. Collection assembly; 151. Mounting bracket; 152. Scraper; 153. Extension bracket; 154. Flexible collection box; 155. Discharge port; 156. Extension sleeve; 157. Limiting spring; 158. Abutment joint. Detailed Implementation

[0047] 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.

[0048] like Figures 1 to 12 As shown, this embodiment of the invention provides a sublimation refining device for caffeine purification, which mainly includes two frames 1 arranged symmetrically on the left and right, and a sealing box 4 is provided at the top of the two frames 1. The two sides of the bottom end of the sealing box 4 are connected to the top of the two frames 1. At the same time, a material tray 3 is provided at the bottom end of the sealing box 4, and longitudinal guide rails 2 are installed on both sides of the frame 1. The two sides of the outer side of the sealing box 4 are equipped with locking blocks, which are movably locked with the longitudinal guide rails 2.

[0049] Specifically, when the material tray 3 carries material and is undergoing sublimation, the material tray 3 is installed directly below the sealed box 4 and is sealed to the sealed box 4 through a sealing gasket. The material to be sublimated is carried inside the material tray 3 for the sublimation operation. When adding material or when sublimation is finished, the material tray 3 can be pulled down to slide along the longitudinal guide rail 2 and separate from the sealed box 4, thus completing the disassembly of the material tray 3.

[0050] In order to provide the main power to the device, a fixed frame 5 is installed at the top of the sealed box 4, and a main motor 6 is installed inside the fixed frame 5. A main shaft 7 is installed at the output end of the main motor 6. The bottom end of the main shaft 7 passes through the top of the sealed box 4 and extends into the inside of the material tray 3, and a material turning assembly 8 located inside the material tray 3 is installed.

[0051] In order to provide uniform heating for the material inside the material tray 3 and improve the sublimation efficiency, this application introduces a material turning component 8. The material turning component 8 mainly includes a sun gear 801 and a gear carrier 803 set on the outer side of the sun gear 801. Planet gears 802 are set at equal angles on the outer side of the sun gear 801. The outer side of the planet gears 802 are meshed with the outer side of the sun gear 801 and the inner side of the gear carrier 803 respectively. The planet gears 802 can rotate on their own axis while rotating around the circumference of the sun gear 801. In order to prevent the planet gears 802 from falling, limit plates are also installed at the upper and lower ends of the planet gears 802 to limit the vertical travel of the planet gears 802. The outer side of the gear carrier 803 is fixedly sleeved with the bottom end of the inner side of the sealing box 4. The middle part of the sun gear 801 is fixedly sleeved with the outer side of the main shaft 7. The sun gear 801, planet gears 802 and gear carrier 803 constitute a planetary gear set.

[0052] Meanwhile, a tilting frame 804 is installed at the bottom of multiple planetary gears 802, and the tilting frame 804 extends into the interior of the material tray 3. At the bottom of the main shaft 7, an installation shaft 805 is installed below the sun gear 801. An oil storage pipe 806 is fixedly sleeved inside the installation shaft 805. The oil storage pipe 806 is filled with heat transfer oil, and an electric heating rod 807 for heating the heat transfer oil is installed inside the oil storage pipe 806. The electric heating rod 807 is connected to an external power source through contacts. An oil heat exchange pipe 808 is fixedly installed at the bottom of the oil storage pipe 806. The heat exchange pipe 808 is connected to the oil storage pipe 806, and the heat exchange pipe 808 is serpentine in shape and extends into the interior of the material tray 3.

[0053] Example: During the sublimation experiment, the material to be sublimated is placed into the material tray 3, and its top is sealed to the bottom of the sealed box 4. At this time, the heat exchange tube 808 and the material tilting frame 804 extend into the material. The electric heating rod 807 is turned on to heat the heat transfer oil inside the oil storage tube 806. This allows for continuous heating of the heat transfer oil inside the heat exchange tube 808, causing the temperature of the heat exchange tube 808 to rise continuously. Simultaneously, the main motor 6 is started, and the main shaft 7 rotates accordingly. Simultaneously, the sun gear 801 at the bottom is driven to rotate. At this time, the heat exchange tube 808 rotates accordingly. Its planetary gear 802 rotates circumferentially relative to the sun gear 801 while rotating on its own axis. It also drives the bottom turning frame 804 to rotate around the sun gear 801 while rotating on its own axis. At this time, multiple turning frames 804 can mix and turn the material, while the heat exchange tube 808 exchanges heat with the material and heats the material. With the mixing and turning of the turning frames 804, the material can be heated evenly and complete the sublimation process.

[0054] To achieve precise control of the caffeine sublimation temperature, a PT100 temperature sensor is also installed inside the material tray 3. This temperature sensor is electrically connected to an external PID temperature control terminal. The atmospheric pressure sublimation temperature range of caffeine is usually controlled between 160°C and 178°C. The system adjusts the output power of the heating rod 807 through a PID algorithm to maintain a constant temperature of the heat transfer oil.

[0055] Its heat exchange efficiency can be calculated and optimized using the following convective heat transfer formula:

[0056]

[0057] Where Q is the heat transfer rate, K is the overall heat transfer coefficient of heat exchanger tube 808, and A is the effective heat transfer area of ​​heat exchanger tube 808. To achieve the logarithmic mean temperature difference between the heat transfer oil and the material, the serpentine heat exchange tube 808 design used in this invention greatly increases the effective heat exchange area A. Combined with the planetary stirring action of the material turning rack 804, it disrupts the temperature boundary layer inside the material, resulting in a significant increase in the overall heat transfer coefficient K, thereby achieving efficient sublimation with lower energy consumption.

[0058] By utilizing the cooperation between the main shaft 7 and the material turning assembly 8, the traditional bottom heating is eliminated, and the material is heated by heat transfer oil. With the mixed turning of multiple material turning frames 804, the material is heated evenly. At the same time, it can reduce the sticking phenomenon caused by uneven heating in traditional heating, improve heating efficiency, improve the overall sublimation effect, and improve material utilization.

[0059] To collect the gas generated during material sublimation, this application introduces a collection assembly 14. Specifically, the collection assembly 14 mainly includes a fixed partition plate 141 and a movable partition plate 142 at the top of the fixed partition plate 141. The fixed partition plate 141 and the movable partition plate 142 are stacked vertically. The fixed partition plate 141 is fixedly connected to the inner wall of the sealing box 4 via an extension block, while the movable partition plate 142 is snapped into the inside of the sealing box 4, restricting its vertical displacement so that it can only move on the horizontal plane. Both the movable partition 142 and the movable partition 142 have multiple inverted conical converging holes 143 circumferentially formed inside. The converging assembly 14 also includes a cam 144 sleeved on the outer side of the main shaft 7. The bottom end of the main shaft 7 passes through the middle of the fixed partition 141 and is movably sleeved between the fixed partition 141 and the fixed partition 141. The middle of the movable partition 142 has a corresponding through hole, and the through hole accommodates the cam 144. The cam 144 rotates under the action of the main shaft 7 and drives the movable partition 142 to rotate eccentrically relative to the fixed partition 141.

[0060] It is worth noting that the outer edge of the movable partition 142 is symmetrically provided with anti-rotation notches, and the inner wall of the sealing box 4 is provided with vertical retaining strips. The anti-rotation notches and the vertical retaining strips are slidably engaged, thereby restricting the movable partition 142 from rotating circumferentially with the cam 144, ensuring that it can only perform translational eccentric movement on the horizontal plane.

[0061] Example: During the collection and gathering of sublimation gas, as the main motor 6 drives the main shaft 7 to rotate continuously, the main shaft 7 synchronously drives the cam 144, which is fixedly sleeved on its outer side, to rotate. Since the moving partition 142 is engaged inside the sealed box 4 and its vertical displacement is restricted, when the cam 144 rotates in the through hole in the middle of the moving partition 142, it forces the moving partition 142 to continuously slide eccentrically against the top surface of the fixed partition 141 on the horizontal plane. During the eccentric movement of the moving partition 142, the multiple inverted conical gathering holes 143 distributed in a circular pattern on its surface will periodically intersect and overlap with the inverted conical gathering holes 143 on the fixed partition 141. When the gas generated by sublimation at the bottom moves upward, it is concentrated and guided through the periodically aligned gathering holes 143 on these two partitions and discharged upward.

[0062] The ratio of the diameter of the lower end (air inlet end) to the diameter of the upper end (air outlet end) of the inverted conical converging hole 143 on the fixed partition 141 and the movable partition 142 is preferably 2:1 to 3:1.

[0063] According to Bernoulli's equation and the continuity equation, the sublimated gas experiences the Venturi effect when passing through an inverted conical orifice, and the gas flow rate... Additions, specifically satisfying the following relationships:

[0064]

[0065] in, The pressure difference between the upper and lower sides of the partition. To increase the density of the sublimated gas, the increased flow rate allows the gas to pass through the converging hole 143 quickly, reducing the residence time below the partition. At the same time, the eccentricity e generated by the cam 144 driving the moving partition 142 is preferably set to 5mm to 15mm. This eccentricity ensures that when the upper and lower converging holes 143 are periodically misaligned, the solid edge of the moving partition can completely cover the dead corner of the fixed partition hole, achieving mechanical shearing and scraping of any possible sublimation crystals.

[0066] By utilizing the linkage between the main shaft 7 and the converging assembly 14, the rotational power of the main shaft is cleverly converted into the horizontal eccentric sliding of the moving baffle 142, realizing the dynamic convergence of gas. On the one hand, the inverted conical converging hole 143 structure acts as a nozzle-like flow guide and acceleration, increasing the flow rate of sublimated gas when passing through the baffle and effectively avoiding excessive gas retention in the lower heated zone. On the other hand, the continuous relative misalignment friction between the moving baffle 142 and the fixed baffle 141 forms continuous mechanical shearing and scraping on the edge of the aperture, effectively preventing the sublimated gas from condensing and crystallizing on the baffle surface or in the pores, thus ensuring that the exhaust channel is always unobstructed and significantly improving the stability of continuous operation and purification and collection efficiency of the device.

[0067] To achieve rapid condensation of sublimated materials, this device also introduces a condensation assembly 13, which is installed at the top of the inner cavity of the sealed box 4. The condensation assembly 13 includes a cooling plate 131, which is installed on the inner top wall of the sealed box 4. The main shaft 7 passes through the bottom end of the cooling plate 131 and is movably connected to the cooling plate 131. To improve heat exchange efficiency, the cooling plate 131 is made of pure copper. A cooling chamber 132 is opened inside the cooling plate 131. A water inlet 133 is opened on one side of the cooling plate 131, and a drain outlet 134 is opened on the other side of the cooling plate 131. The water inlet 133 and the drain outlet 134 are connected to the cooling chamber 132. Both the water inlet 133 and the drain outlet 134 penetrate the outer side of the sealed box 4 and are connected to the external cooling water pipe.

[0068] Specifically, cooling water is introduced into the inlet 133 by an external water pump, so that the cooling water fills the cooling chamber 132, and the cooled water after heat exchange is discharged through the drain 134, thus completing the circulation process.

[0069] After sublimation, the material is gathered by the gathering component 14 and rises to meet the cooling plate 131, which has a lower temperature. It exchanges heat with the cooling water inside the plate, causing the caffeine to condense into powder and adhere to the bottom of the cooling plate 131, thus completing the condensation operation.

[0070] To facilitate the collection of sublimated caffeine, this application introduces a collection assembly 15. The collection assembly 15 mainly includes a mounting bracket 151 fixedly sleeved on the outer side of the main shaft 7. A scraper 152 is mounted on one side of the mounting bracket 151, located below the cooling plate 131, with the top end of the scraper 152 in close contact with the bottom end of the cooling plate 131. An extension bracket 153 is mounted on the side of the scraper 152 away from the mounting bracket 151, and a flexible collection box 15 is mounted on the inner side of the extension bracket 153, located directly below the scraper 152. 4. The bottom of the flexible collection box 154 is designed to be inclined away from the main shaft 7, and a discharge port 155 is provided at the most inclined end. Meanwhile, an extension rod 156 is movably sleeved inside the extension frame 153. The top end of the extension rod 156 is connected to the side of the flexible collection box 154 through a connecting block. A limit spring 157 is movably sleeved on the outer side of the extension rod 156. The upper and lower ends of the limit spring 157 are connected to the inner bottom wall of the extension frame 153 and the connecting block at the top end of the extension rod 156.

[0071] Specifically, under the rotation of the main shaft 7, the scraper 152 can rotate circumferentially relative to the bottom end of the cooling plate 131 to scrape off the caffeine powder adhering to its bottom end. The scraped caffeine falls into the interior of the flexible collection box 154 for collection.

[0072] To ensure that caffeine can be centrally extracted after collection, an abutment ring 9 is provided below the collection component 15. The abutment ring 9 is installed on the inner wall of the sealed box 4 through a connecting block and is located directly below the collection component 15. The abutment ring 9 is circular, and the top near the outer side protrudes upward to form a ring with a height higher than the inner side. A fully penetrating discharge port 11 is opened on the inner side ring with a lower height, and a discharge pipe 12 is fixedly connected to the bottom end of the discharge port 11. The output end of the discharge pipe 12 penetrates the outer side of the sealed box 4. At the same time, a groove 10 is opened on the outer side ring with a higher height on the abutment ring 9. The groove 10 is opened on one side of the discharge port 11 and is parallel to the discharge port 11.

[0073] Specifically, the top of the abutment 158 ​​is always in contact with the top of the higher ring on the outer side of the abutment ring 9, and rotates circumferentially relative to the abutment ring 9 under the action of the main shaft 7. At this time, the limit spring 157 is in a continuously compressed state, and the bottom of its discharge port 155 is blocked by the top of the ring on the inner side of the abutment ring 9, so the powder inside the flexible collection box 154 cannot be discharged through the discharge port 155.

[0074] When the abutment 158 ​​rotates to the groove 10, the groove 10 is concave, causing the limit spring 157 to recover its deformation and drive the flexible collection box 154 and the discharge port 155 to move down. At this time, the discharge port 155 corresponds to the discharge port 11, and the powder inside the flexible collection box 154 is discharged through the discharge port 11 and the discharge pipe 12.

[0075] The bottom surface of the cooling plate 131 is coated with a polytetrafluoroethylene non-stick coating. This coating ensures the excellent thermal conductivity of the cooling plate 131 while significantly reducing the surface energy, so that the scraper 152 requires less torque when scraping in the circumferential direction, and caffeine powder is less likely to remain. The flexible collection box 154 is made of pharmaceutical grade fluororubber material, which has excellent high temperature resistance and fatigue expansion resistance.

[0076] To ensure that the discharge port 155 sinks and resets instantly when the abutment 158 ​​crosses the groove 10, the spring force output of the limit spring 157 follows Hooke's Law:

[0077]

[0078] The set spring stiffness coefficient k needs to match the weight of the flexible collection box 154 when fully loaded, ensuring that in the non-grooved area, the spring's compressive rebound force F is greater than the sum of the total weight of the collection box when fully loaded and the downward friction force, thus guaranteeing excellent sealing performance. When reaching the groove 10, the groove depth... (i.e., the spring extension) is equal to the stroke required to align the discharge port 155 with the discharge port 11, which is usually set to 20mm to 30mm.

[0079] It is worth noting that the groove 10 on the abutment ring 9 is a long arc-shaped groove with a specific curvature. When the abutment 158 ​​slides into the groove, the main motor 6 is controlled to reduce its speed, so that the discharge port 155 and the discharge port 11 are in a docking state to ensure that the powder is discharged completely. The upper opening of the discharge port 11 is designed as a long strip opening with the same curvature as the groove to prolong the connection time.

[0080] Example: During the condensation and collection of caffeine gas, cooling water is first pumped into the inlet 133 by an external water pump, filling the cooling chamber 132 inside the cooling plate 131 made of pure copper. The cooled water, after heat exchange, is discharged from the drain 134, forming a continuous cooling cycle. The caffeine sublimation gas, guided upward by the collecting component 14, rapidly undergoes heat exchange when it encounters the lower temperature bottom of the cooling plate 131, condensing into caffeine powder that adheres to its bottom surface. During this synchronous process, the rotation of the main shaft 7 drives the fixed mounting bracket 151 to rotate, causing the scraper 152 to continuously rotate circumferentially against the bottom of the cooling plate 131, scraping off the adhered caffeine powder in real time. The scraped-off powder then falls into the flexible collection box 154 directly below for collection. In the normal state of the collection assembly 15 rotating with the main shaft 7, the abutment 158 ​​always presses against the top surface of the higher outer ring of the abutment ring 9, forcing the limit spring 157 into a compressed state. At this time, the discharge port 155 is blocked by the inner ring of the abutment ring 9, and the powder is sealed inside the box. When the abutment 158 ​​rotates to the position of the groove 10, the groove 10 loses its support due to its concavity, and the limit spring 157 instantly restores its deformation and pushes the extension sleeve 156 downward, causing the flexible collection box 154 and the discharge port 155 to move downward as a whole. At this time, the discharge port 155 precisely aligns with the through discharge port 11, and the powder temporarily stored inside the flexible collection box 154 is discharged through the discharge port 11 and the discharge pipe 12. After passing the groove, the mechanism resets, thus completing the cyclical automatic collection and unloading process.

[0081] The system utilizes a pure copper cooling plate 131 with continuous internal water circulation to significantly improve the heat exchange efficiency of the gas-solid phase change. The dynamic scraping design of the scraper 152 effectively prevents powder accumulation at the bottom of the cooling plate, avoiding increased thermal resistance due to thickened crystal layer and ensuring that the condensation component 13 is always in a highly efficient heat exchange state. Furthermore, the collection component 15, through the pure mechanical linkage of the abutment joint 158, the limit spring 157, and the groove 10 of the abutment ring 9, transforms the rotation of the main shaft into the periodic temporary storage, alignment, sinking discharge, and resetting actions of the flexible collection box 154. This mechanism not only achieves the centralized and timed automatic discharge of materials, eliminating the tedious manual shutdown for cleaning, but also maintains the high sealing performance inside the equipment, effectively preventing dust and material loss during the discharge process, and significantly improving the continuous production efficiency of the purification device and the purity of the collected product.

[0082] Example: To further enhance the automation level of the device, this example introduces an external industrial robot to complete the automatic feeding operation based on the original mechanism. Specifically:

[0083] When the previous batch of sublimation is completed or the initial feeding is prepared, the external robot arm accurately identifies and grabs the material tray 3 located directly below the sealed box 4. Then, the robot arm applies a downward pulling force to pull the material tray 3 down, so that the locking block on its outer side slides down along the longitudinal guide rail 2 on both sides of the inner wall of the frame 1, thereby completely separating it from the bottom of the sealed box 4 and completing the automatic disassembly of the material tray 3.

[0084] The robotic arm smoothly moves the disassembled material tray 3 to the automatic feeding station, where the external quantitative feeding system precisely feeds the caffeine crude material to be sublimated into the inside of the material tray 3.

[0085] After carrying the material to be sublimated, the robot arm grabs the material tray 3 again, making it move and engage with the longitudinal guide rail 2 on the frame 1, and controls the material tray 3 to slide upward along the longitudinal guide rail 2. The robot arm continuously lifts the material tray 3, so that its top is tightly attached to the bottom of the sealed box 4. The internal sealing gasket ensures that an airtight connection is formed between the material tray 3 and the sealed box 4, completing the automatic closure.

[0086] As the material tray 3 is pushed into the docking and closing position by the robotic arm, the serpentine heat exchange tube 808 located at the bottom of the main shaft 7 and the multiple material turning frames 804 at the bottom of the material turning assembly 8 will automatically go into the newly filled material. After the docking is completed, the robotic arm will release and leave the work area. The system control terminal can then simultaneously turn on the heating rod 807 and the main motor 6 to start a new stage of heating and planetary mixing and sublimation process.

[0087] Working principle and usage process of this invention:

[0088] When performing the sublimation, condensation, and collection refining of caffeine gas, the equipment is first assembled and prepared for startup. The material tray 3, carrying the crude caffeine to be sublimated, is slid upwards along the longitudinal guide rail 2 from below, so that its top is tightly fitted against the bottom of the sealed box 4. A sealing gasket ensures an airtight connection between the two. At this time, the mounting shaft 805 at the bottom of the main shaft 7, the serpentine heat exchange tube 808, and multiple material tilting racks 804 are all inserted into the material inside the material tray 3. Then, the external cooling water is turned on. The pump injects cooling water from the inlet 133, filling the cooling chamber 132 inside the pure copper cooling plate 131. The warm water after heat exchange is then continuously discharged through the drain 134, forming a stable top cooling cycle. At the same time, the system connects the power supply of the heating rod 807 through the PID temperature control terminal to heat the heat transfer oil inside the oil storage pipe 806. The heat is quickly transferred to the heat transfer oil in the heat exchange tube 808, causing its temperature to rise steadily and be maintained in the set sublimation temperature range of 160°C to 178°C.

[0089] After the heating system stabilizes, the main motor 6 is started. The output of the main motor 6 drives the main shaft 7 to rotate at a constant speed, thereby transmitting power from top to bottom to various linkage mechanisms. In the bottom heating zone, the main shaft 7 drives the sun gear 801 and the fixedly connected heat exchange tube 808 to rotate synchronously. The rotation of the sun gear 801 drives the planetary gear 802, which meshes with it, to rotate on its own axis within the gear frame 803 and revolve around the sun gear 801. This, in turn, drives the bottom turning rack 804 to mix and turn the caffeine material in multiple dimensions. This dynamic stirring, combined with the efficient heat transfer of the serpentine heat exchange tube 808, makes the internal heating of the material extremely uniform, and the caffeine begins to rise in large quantities and rapidly. The gas produced by sublimation surges upwards. At this time, the main shaft 7 synchronously drives the cam 144 fixed on it to rotate. The cam 144 rotates in the through hole in the middle of the moving partition 142, forcing the moving partition 142 to continuously slide eccentrically against the top surface of the fixed partition 141 while restricting its vertical displacement. During this process, the inverted conical converging holes 143 distributed in a circle on the two partitions periodically intersect and overlap. When the gas passes through these holes, it is significantly accelerated and concentrated upwards due to the Venturi effect. At the same time, the eccentric frictional motion of the moving partition 142 continuously performs mechanical shearing on the edge of the aperture, effectively preventing the gas from condensing and clogging.

[0090] The high-speed caffeine gas passing through the collecting component 14 continues to rise until it contacts the bottom surface of the cooler plate 131 at the top of the sealed box 4, where a gas-solid phase change occurs instantaneously, condensing into high-purity caffeine powder that adheres to the cooler surface coated with an anti-stick coating. Simultaneously, the main shaft 7 drives the mounting bracket 151 of the collecting component 15 to rotate continuously, causing the scraper 152, which is in close contact with the cooler plate 131 at its top, to move circumferentially, scraping off the newly adhered caffeine powder in real time. The scraped powder then falls into the flexible collecting box 154 directly below. During most of the rotation stroke of the collecting component 15, the abutment 158 ​​at the bottom of the extension sleeve 156 constantly presses against the higher annular surface of the abutment ring 9, keeping the limit spring 157 compressed and the outlet 155 of the flexible collecting box 154 abutted. The lower inner ring of ring 9 firmly seals the powder, which is temporarily stored in the box. When the abutment 158 ​​rotates with the main shaft 7 to the groove 10 on the abutment ring 9, the supporting force disappears instantly. The limit spring 157 releases its elasticity and pushes the extension sleeve 156 downward, causing the flexible collection box 154 and the discharge port 155 to sink as a whole. At this time, the discharge port 155 is precisely aligned with the discharge port 11 that is completely penetrated on the abutment ring 9. The purified caffeine powder collected in the box passes through the discharge port 11 and enters the discharge pipe 12 under the action of gravity and inclined plane, and is concentrated and led out to the outside of the device for collection. As the main shaft 7 continues to rotate, the abutment 158 ​​slides out of the groove 10 and is lifted up again. The discharge port 155 is then reset and resealed, thus realizing a continuous, closed, and efficient purification cycle of sublimation, scraping, and automatic unloading.

Claims

1. Sublimation refining apparatus for purification of caffeine, characterized in that: Includes a frame (1), a sealed box (4) mounted on the frame (1), a material tray (3) connected to the bottom of the sealed box (4), and a main motor (6) that provides rotational power; The main motor (6) drives a main shaft (7) that runs longitudinally through the sealed box (4). The main shaft (7) is connected from bottom to top to a material turning component (8) that extends into the material tray (3), a gathering component (14) located above the material tray (3), and a collection component (15) located at the top of the sealed box (4). The material turning assembly (8) includes a heat exchange tube (808) that rotates synchronously with the main shaft (7). The heat exchange tube (808) is configured to extend into the material to provide an internal heat source. The material turning assembly (8) is configured to be driven by the main shaft (7) to perform planetary mixing and stirring of the material around the heat exchange tube (808). The converging assembly (14) includes a fixed partition (141) and a movable partition (142) stacked on top of each other. Both the fixed partition (141) and the movable partition (142) are provided with multiple converging holes (143). The main shaft (7) converts the rotational power into eccentric displacement through the transmission mechanism and drives the movable partition (142) to slide horizontally eccentrically relative to the fixed partition (141), so that the converging holes (143) on the two partitions are periodically interleaved and generate mechanical shearing and scraping on the pores. The inner top wall of the sealed box (4) is provided with a condensation component (13) for the sublimation gas. The main shaft (7) drives the collection component (15) to rotate circumferentially against the bottom surface of the condensation component (13) to scrape off and temporarily store the crystalline powder. The collection component (15) is triggered by a mechanical structure at a specific phase of its circumferential rotation trajectory to discharge material downwards.

2. The sublimation refining apparatus for purifying caffeine according to claim 1, characterized by: The material turning assembly (8) further includes a sun gear (801) fixedly sleeved with the main shaft (7) and a gear frame (803) fixed to the bottom of the sealing box (4). A planetary gear (802) is provided between the sun gear (801) and the gear frame (803) and meshes with both of them. The bottom ends of the multiple planetary gears (802) are respectively coaxially connected to a material turning frame (804) extending into the material tray (3).

3. The sublimation refining apparatus for purifying caffeine according to claim 2, characterized by: The bottom end of the main shaft (7) is connected to a mounting shaft (805) located below the sun gear (801), and an oil storage pipe (806) is fixedly sleeved inside the mounting shaft (805). An electric heating rod (807) is installed inside the oil storage pipe (806). The heat exchange tube (808) is serpentine and fixedly connected to the bottom end of the oil storage pipe (806). The oil storage pipe (806) and the heat exchange tube (808) are filled with heat-conducting oil.

4. The sublimation refining apparatus for purifying caffeine according to claim 1, characterized by: The transmission mechanism that drives the movable partition (142) includes a cam (144) sleeved on the outer side of the main shaft (7). The edge of the fixed partition (141) is fixedly connected to the inner wall of the sealing box (4), and the movable partition (142) is movably engaged in the sealing box (4) and its vertical displacement is restricted. The movable partition (142) has a through hole in the middle to accommodate the cam (144). The cam (144) rotates with the main shaft (7) and drives the movable partition (142) to slide eccentrically. The converging holes (143) on both the fixed partition (141) and the moving partition (142) are inverted conical structures with the lower air inlet larger than the upper air outlet.

5. The sublimation refining apparatus for caffeine purification according to claim 1, characterized in that: The condensation assembly (13) includes a cooling plate (131) installed on the top wall inside the sealed box (4), and the main shaft (7) passes upward through the bottom surface of the cooling plate (131) and is movably sleeved therewith; The cooling plate (131) has a cooling chamber (132) for circulating cooling water to pass through. The cooling plate (131) has an inlet (133) and a drain (134) on both sides, which penetrate the outer wall of the sealed box (4) and connect to the cooling chamber (132).

6. The sublimation refining apparatus for caffeine purification according to claim 5, characterized in that: The collecting assembly (15) includes a mounting bracket (151) fixedly sleeved on the main shaft (7), and a scraper (152) is provided on one side of the mounting bracket (151) located directly below the cooling plate (131) and with its top surface in close contact with the bottom surface of the cooling plate (131). The scraper (152) is connected to a downwardly extending extension frame (153) at one end away from the mounting frame (151), and a flexible collection box (154) located directly below the scraper (152) is installed on the inner side of the extension frame (153). The bottom of the flexible collection box (154) is inclined outward, and a discharge port (155) is provided at the farthest end of the inclination.

7. The sublimation refining apparatus for caffeine purification according to claim 6, characterized in that: The extension frame (153) has a vertical extension rod (156) movably sleeved inside its side wall. The upper end of the extension rod (156) is linked to the side of the flexible collection box (154) through a connecting block. The extension sleeve (156) is fitted with a limiting spring (157) on its outer side. The upper end of the limiting spring (157) abuts against the connecting block, and the lower end abuts against the inner bottom wall of the extension frame (153). The extension sleeve (156) extends downward through the extension frame (153) and is fixed with an abutment (158).

8. The sublimation refining apparatus for caffeine purification according to claim 7, characterized in that: The collecting component (15) is provided with an abutment ring (9) fixed to the inner wall of the sealing box (4) directly below it, and the bottom end of the abutment joint (158) abuts against the top surface of the abutment ring (9). The abutting ring (9) is a stepped ring, with the outer ring being higher than the inner ring. The top surface of the outer ring is partially recessed and has a groove (10). The inner ring has a through discharge port (11) at the side corresponding to the groove (10). The bottom end of the discharge port (11) is connected to a discharge pipe (12) that extends out of the sealed box (4). When the main shaft (7) drives the abutment (158) to rotate to the groove (10), the limiting spring (157) restores its deformation and drives the flexible collection box (154) to move downward as a whole, so that the discharge port (155) is connected to the discharge port (11).

9. The sublimation refining apparatus for caffeine purification according to claim 1, characterized in that: The top of the sealed box (4) is fixed with a mounting bracket (5) for installing the main motor (6). The inner walls of both sides of the frame (1) are equipped with longitudinal guide rails (2). The lower end of the outer side of the sealed box (4) is provided with a locking block. The sealed box (4) is movably locked onto the longitudinal guide rail (2) by the locking block. The material tray (3) is configured to slide up and down along the longitudinal guide rail (2) to achieve disassembly and closure.

10. The sublimation refining apparatus for caffeine purification according to claim 6, characterized in that: The cooling plate (131) is made of pure copper and its bottom surface is coated with a polytetrafluoroethylene anti-stick coating. The flexible collection box (154) is made of pharmaceutical grade fluororubber. The material tray (3) has a temperature sensor installed inside.

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