Steam heat exchanger for tobacco extraction

Abstract

The present application relates to the technical field of tobacco recycling, and discloses a steam heat exchanger for tobacco extraction, which comprises an inlet and outlet cavity, a heating cavity and a transfer cavity. The inlet and outlet cavity and the transfer cavity are communicated through heat exchange pipes, the inlet and outlet cavity is divided into upper and lower cavities by a layered plate, and the heat exchange pipes pass through the heating cavity. The heating cavity is provided with odd number of at least three drainage plates staggered in upper and lower positions; the drainage plate between the inlet and outlet cavity and the inlet end is close to the inlet and outlet cavity, the drainage plate between the outlet end and the transfer cavity is close to the transfer cavity, the drainage plate is provided with a heat exchange pipe mounting hole and a vent hole. The bottom of the heat exchange pipe below the heating cavity is provided with a gas guide plate, the gas guide plate is parallel to the heat exchange pipe and leaves a gap, and a drain hole is arranged between the two drainage plates at the tail portion. The energy-saving heat exchanger reduces the temperature difference of the heating cavity, removes condensate water, adapts to multiple steam working conditions, improves the energy-saving effect and adaptability of heat exchange, and solves the problems of large temperature difference of the heat exchanger, difficulty in removing condensate water and difficulty in adapting to multiple steam working conditions in the extraction of tobacco.

Description

Technical Field

[0001] This invention relates to the field of tobacco recycling technology, specifically a steam heat exchanger for tobacco extraction. Background Technology

[0002] In tobacco extraction, steam heat exchangers are key equipment for heating the extraction medium (carbon dioxide). Their heat exchange efficiency and temperature stability directly affect the extraction rate and quality of the active ingredients in tobacco. Existing steam heat exchangers for tobacco extraction typically include a feed chamber, a heating chamber, and a discharge chamber. The feed chamber and discharge chamber are connected by heat exchange tubes, and the medium inside the heat exchange tubes is heated by the flow of steam in the heating chamber.

[0003] However, existing steam heat exchangers have the following prominent problems when used in tobacco extraction:

[0004] Significant temperature difference exists between the top and bottom of the heating chamber: After steam is introduced into the heating chamber, it tends to flow rapidly along the inner side of the chamber, causing a significant temperature stratification between the newly introduced high-temperature steam and the condensed cold air accumulated at the bottom. This not only reduces heat exchange uniformity but also generates thermal stress due to the excessive temperature difference, affecting the service life of the equipment. Especially in scenarios where precise temperature control is required for tobacco extraction, temperature fluctuations can lead to uneven heating of the extraction medium, thereby affecting the stability of the effective components in tobacco.

[0005] Incomplete condensate removal: After steam releases heat on the surface of the heat exchange tubes, it easily forms condensate. This condensate adheres to the outer wall of the heat exchange tubes, especially in the bottom area, forming an insulating layer that hinders heat transfer and reduces heat exchange efficiency. Existing equipment mostly relies on natural dripping or simple hydrophobic structures for drainage, which cannot effectively remove condensate adhering to the surface of the heat exchange tubes. Long-term use may also lead to equipment corrosion due to condensate accumulation.

[0006] Poor adaptability and difficulty in meeting the needs of multiple operating conditions: During tobacco extraction, different steam parameters (such as high-flow-rate low-temperature steam and low-flow-rate high-temperature steam) need to be selected according to the differences in extraction processes. The existing heat exchanger has a fixed steam flow path. When the temperature difference between the steam and the extraction medium is small (such as in the high-flow-rate low-temperature steam scenario), the steam is easy to condense, but the condensate removal cannot be enhanced by optimizing the flow path; when the temperature difference is large (such as in the low-flow-rate high-temperature steam scenario), the steam is difficult to diffuse fully, resulting in uneven temperature distribution inside the heating chamber, and it is impossible to take into account the heat exchange effect under different operating conditions.

[0007] The aforementioned problems not only reduce the efficiency and quality stability of tobacco extraction, but also increase equipment maintenance costs and heat exchanger energy consumption, thus limiting the application of steam heat exchangers in the tobacco extraction field. Therefore, developing an energy-saving steam heat exchanger that can reduce the temperature difference in the heating chamber, efficiently remove condensate, and adapt to multiple operating conditions has become an urgent technical problem to be solved in this field. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] To address the shortcomings of existing technologies, this invention provides a steam heat exchanger for tobacco extraction, which has the advantages of reducing the temperature difference in the heating chamber, removing condensate, adapting to multiple steam conditions, and improving heat exchange efficiency and adaptability. It solves the problems of large temperature difference in the heating chamber, difficulty in removing condensate, and inability to adapt to multiple steam conditions when using steam heat exchangers in tobacco extraction.

[0010] (II) Technical Solution

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] A steam heat exchanger for tobacco extraction includes an inlet / outlet chamber, a heating chamber, and a transfer chamber. The inlet / outlet chamber and the transfer chamber are connected by a heat exchange tube. The inlet / outlet chamber is divided into upper and lower chambers by a layered plate. The heat exchange tube passes through the heating chamber. The heating chamber has a steam inlet and a steam outlet located above one end and below the other end, respectively. At least three guide plates are arranged alternately in the heating chamber, with the guide plate closest to the inlet / outlet chamber and the guide plate closest to the transfer chamber located at... The steam inlet is located at the upper part of the heating chamber, between the guide plate closest to the inlet and outlet chambers and the inlet and outlet chambers. The steam outlet is located at the lower part of the heating chamber, between the guide plate closest to the transfer chamber and the transfer chamber. The guide plate is provided with a heat exchange tube mounting hole for passing through the heat exchange tube and a vent hole for slow air passage. A guide plate is provided at the bottom of the heat exchange tube located at the lower part of the heating chamber. The guide plate is parallel to the heat exchange tube and has a gap with the heat exchange tube. A drain hole is provided at the tail of the guide plate in the area between the two guide plates.

[0013] Preferably, the heat exchange tube located at the bottom of the heating chamber is a non-circular tube. The outer wall of the non-circular tube is provided with a horizontally uniform array of triangular protrusions. The cross-section of the triangular protrusion is triangular. In addition to the side closest to the inside of the non-circular tube, the triangular cross-section of the triangular protrusion also includes a long side and a short side. The included angle between the long side and the short side is an obtuse angle. The long side faces the side closer to the inlet and outlet chambers, and the short side faces the side closer to the transfer chamber.

[0014] Preferably, on the flow guide plate located at the bottom of the heating chamber, the vent hole is positioned above the heat exchange tube mounting hole for the shaped tube to pass through, and the vent hole is connected to the heat exchange tube mounting hole through a vertical channel. The flow guide plate is also provided with an exhaust hole below the heat exchange tube mounting hole for the shaped tube to pass through, and the exhaust hole extends through both sides of the flow guide plate. The heat exchange tube mounting hole and the corresponding exhaust hole are connected through a vertical channel, and the lowest point of the exhaust hole is higher than or flush with the air guide plate.

[0015] Preferably, on the flow guide plate located at the bottom of the heating chamber, the vent is configured in the shape of a funnel, with the opening of the vent near the inlet / outlet chamber being larger than the opening near the transfer chamber.

[0016] Preferably, the inlet and outlet chambers are provided with a carbon dioxide inlet and a carbon dioxide outlet, the carbon dioxide inlet being connected to the lower cavity of the guide plate, and the carbon dioxide outlet being connected to the upper cavity of the guide plate.

[0017] Preferably, a pressure relief valve and a temperature sensor are also provided on the pipe connecting the carbon dioxide inlet to the carbon dioxide storage tank, and a shut-off valve and a temperature sensor are also provided on the pipe connecting the carbon dioxide outlet to the extraction vessel.

[0018] Preferably, a partition is provided between the inlet / outlet chamber and the heating chamber, and between the transfer chamber and the heating chamber, and the heat exchange tube passes through the partition.

[0019] Preferably, the end of the air guide plate is fixed to the partition plate or the diversion plate.

[0020] Preferably, the air guide plate is an arc-shaped plate, and the end of the air guide plate near the inlet / outlet chamber is higher than the end near the transfer chamber.

[0021] Preferably, the inner wall of the vertical channel between the vent and the heat exchange tube mounting hole is provided with a flow guiding structure. The flow guiding structure is spiral or strip-shaped protrusion, which can guide the steam to form a rotating flow in the channel and enhance the contact effect between the steam and the outer wall of the shaped tube. The inner diameter of the exhaust hole is larger than the inner diameter of the vertical channel, and the outlet direction of the exhaust hole is towards the area above the air guide plate, so that the steam passing through the exhaust hole can directly act on the condensate above the air guide plate to help remove the condensate on the outer wall of the shaped tube.

[0022] (III) Beneficial Effects

[0023] Compared with the prior art, the present invention provides a steam heat exchanger for tobacco extraction, which has the following advantages:

[0024] 1. This steam heat exchanger for tobacco extraction utilizes an odd number of guide plates within the heating chamber, each with vents allowing for limited airflow. A guide plate is positioned at the bottom of the heat exchange tubes. Firstly, condensed gas accumulates at the bottom of the heating chamber. The guide plates disperse the incoming steam, reducing the temperature difference between the top and bottom of the heating chamber. Secondly, the guide plate envelops the downward-rushing steam around the outside of the heat exchange tubes, removing condensate adhering to the bottom tubes. Finally, the vents on the guide plates are suitable for various heat exchange modes. When high-velocity, low-temperature steam is introduced, the temperature difference between the steam and carbon dioxide is small, making steam condense easily. In this case, most steam travels along the S-shaped path formed by the guide plates, improving condensate removal efficiency. When low-velocity, high-temperature steam is introduced, the temperature difference between the steam and carbon dioxide is large, making steam less prone to condensation. In this case, most steam passes through the vents, spreading within the heating chamber.

[0025] 2. The steam heat exchanger for tobacco extraction features a uniform array of triangular protrusions on the surface of the shaped tube, with the longer side facing the direction from which the steam originates. Firstly, the obtuse angles of the longer and shorter sides increase the surface area of ​​the shaped tube, enhancing the heat exchange efficiency between carbon dioxide and steam inside the tube and preventing the formation of a continuous water film on the tube surface. Secondly, condensate is more easily accumulated on the protruding parts of the longer and shorter sides, making it easier to be blown away by the airflow. Conversely, condensate is less likely to accumulate in the concave parts of the longer and shorter sides, which are the closest to the inner wall of the tube, reducing the impact of condensate on the carbon dioxide inside. Finally, the longer side facing the direction from which the steam originates increases the efficiency of the airflow in removing condensate.

[0026] 3. The steam heat exchanger for tobacco extraction uses vertical channels to connect the vent hole with the heat exchange tube mounting hole and the heat exchange tube mounting hole with the exhaust hole. First, it improves the ventilation efficiency in the heat exchange tube mounting hole, avoiding the low heat exchange efficiency of the irregular tube section located in the heat exchange tube mounting hole. It also avoids the accumulation of condensate between the outside of the irregular tube and the heat exchange tube mounting hole due to the triangular boss structure. Second, the exhaust hole connects the two sections of the air guide plate, accelerating the water removal efficiency of the airflow on the next section of the air guide plate. It can also use the airflow of the air guide plate to accelerate the steam flow speed in the heat exchange tube mounting hole.

[0027] 4. The steam heat exchanger for tobacco extraction, by setting the vent hole to a funnel shape, can guide a portion of the steam passing through the vent hole into the heat exchange tube mounting hole, and can also accelerate the flow rate of the steam after passing through the vent hole. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the heat exchanger body of the present invention.

[0029] Figure 2This is a schematic diagram showing the connection between the heat exchanger body and the extraction vessel of the present invention.

[0030] Figure 3 This is an exploded view of the heat exchanger body of the present invention.

[0031] Figure 4 This is a cross-sectional view of the heat exchanger body of the present invention.

[0032] Figure 5 This is a schematic diagram of the heat exchange tube of the present invention.

[0033] Figure 6 This is a schematic diagram of the irregular-shaped tube of the present invention.

[0034] Figure 7 This is a partial cross-sectional view of the irregularly shaped tube of the present invention.

[0035] Figure 8 This is a schematic diagram of the air guide plate of the present invention.

[0036] Figure 9 This is a schematic diagram of the structure of the irregular tube and air guide plate of the present invention installed and fixed on the diversion plate.

[0037] Figure 10 This is a cross-sectional view of the irregularly shaped tube and air guide plate of the present invention installed and fixed on the diversion plate.

[0038] In the diagram: 11. Carbon dioxide inlet; 12. Feed inlet / outlet chamber; 13. Heating chamber; 14. Transfer chamber; 15. Carbon dioxide outlet; 16. Steam inlet; 17. Steam outlet; 18. Heat exchanger tube; 19. Baffle plate;

[0039] 2. Drain plate; 21. Heat exchanger tube mounting hole; 22. Vent hole; 23. Exhaust hole; 121. Layered plate;

[0040] 3. Irregularly shaped tube; 31. Triangular boss; 311. Long side; 312. Short side;

[0041] 4. Air guide plate; 41. Drain hole;

[0042] 5. Extraction vessel. Detailed Implementation

[0043] 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.

[0044] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] In addition, a fixed connection refers to a connection in which parts or components are fixed and there is no relative movement; a transmission connection refers to a connection in which mechanical motion or torque is transmitted to other working parts through a transmission component; a sliding connection refers to a connection in which two objects are in contact but not fixed and can slide relative to each other; and a rotational connection refers to a connection in which two objects are in contact but not fixed and can rotate relative to each other.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0047] Example 1:

[0048] This embodiment provides a steam heat exchanger for tobacco extraction, which has the following technical features.

[0049] Please see Figure 1-10 A steam heat exchanger for tobacco extraction includes an inlet / outlet chamber 12, a heating chamber 13, and a transfer chamber 14. The inlet / outlet chamber 12 and the transfer chamber 14 are connected by a heat exchange tube 18. The inlet / outlet chamber 12 is divided into upper and lower chambers by a layered plate 121. The heat exchange tube 18 passes through the heating chamber 13. The heating chamber 13 has a steam inlet end 16 near one end and a steam outlet end 17 near the other end.

[0050] The heating chamber 13 is provided with at least three diverting plates 2 arranged alternately in an odd number. The diverting plate 2 closest to the inlet / outlet chamber 12 and the diverting plate 2 closest to the transfer chamber 14 are both located at the upper position in the heating chamber 13. The steam inlet end 16 is located between the diverting plate 2 closest to the inlet / outlet chamber 12 and the inlet / outlet chamber 12. The steam outlet end 17 is located between the diverting plate 2 closest to the transfer chamber 14 and the transfer chamber 14. The diverting plate 2 is provided with a heat exchange tube mounting hole 21 for passing through the heat exchange tube 18 and a vent hole 22 for slow air passage.

[0051] A guide plate 4 is provided at the bottom of the heat exchange tube 18 located in the lower part of the heating chamber 13. The guide plate 4 is parallel to the heat exchange tube 18 and there is a gap between the guide plate 4 and the heat exchange tube 18. A drain hole 41 is provided at the tail of the guide plate 4 in the area between the two guide plates 2.

[0052] This technical solution, through the S-shaped flow path design of the guide plate 2 and the flow diversion and adaptation mechanism of the vent, can accurately match the heat exchange requirements of high and low flow rates and different temperatures of steam in the tobacco extraction process: When high flow rate low temperature steam (temperature difference ≤15℃) is used, the steam concentrates on scouring the outer wall of the heat exchange tube along the directional flow path formed by the guide plate 2. Combined with the airflow constraint effect of the air guide plate 4, the condensate removal efficiency is improved by more than 40% compared with the traditional structure; When low flow rate high temperature steam (temperature difference ≥30℃) is used, the steam quickly diffuses to the entire heating chamber through the vent. Combined with the boss structure of the irregular tube, the temperature difference between the upper and lower parts of the heating chamber is reduced by 35%, which effectively avoids the fluctuation of the extraction rate of tobacco effective components caused by local overheating or uneven heating of carbon dioxide in the extraction medium. At the same time, it significantly reduces the impact of condensate on the heat exchange of carbon dioxide in the tube, ensuring the temperature stability of the extraction process.

[0053] It should be noted that after the steam enters the heating chamber 13 from the steam inlet 16, most of the steam flows in the heating chamber 13 along the S-shaped route formed by multiple guide plates 2. A small portion of the steam spreads directly in the heating chamber 13 through the vent holes 22 on the guide plates 2. After a long period of operation, cold air accumulates at the bottom, and the newly entering airflow will impact the cold air at the bottom under the action of the guide plates 2, reducing the accumulation of cold air.

[0054] It should be noted that the tail of the air guide plate 4 refers to the section of the air guide plate 4 that is located away from the inlet / outlet chamber 12.

[0055] In an optional embodiment, the heat exchange tube 18 located at the bottom of the heating chamber 13 is configured as a shaped tube 3. The outer wall of the shaped tube 3 is provided with a horizontally uniform array of triangular protrusions 31. The cross-section of the triangular protrusions 31 is triangular. In addition to the side closest to the inside of the shaped tube 3, the triangular cross-section of the triangular protrusions 31 also includes a long side 311 and a short side 312. The included angle between the long side 311 and the short side 312 is an obtuse angle. The long side 311 faces the side close to the inlet / outlet chamber 12, and the short side 312 faces the side close to the transfer chamber 14.

[0056] In an optional embodiment, on the guide plate 2 located at the bottom of the heating chamber 13, a vent 22 is provided above the heat exchange tube mounting hole 21 for passing through the shaped tube 3. The vent 22 and the heat exchange tube mounting hole 21 are connected by a vertical channel. The guide plate 2 is also provided with an exhaust hole 23 below the heat exchange tube mounting hole 21 for passing through the shaped tube 3. The exhaust hole 23 passes through both sides of the guide plate 2. The heat exchange tube mounting hole 21 and the corresponding exhaust hole 23 are connected by a vertical channel. The lowest point of the exhaust hole 23 is higher than or flush with the air guide plate 4.

[0057] In an optional embodiment, on the guide plate 2 located at the bottom of the heating chamber 13, the vent 22 is configured in the shape of a flared mouth, with the opening of the vent 22 on the side near the inlet / outlet chamber 12 being larger than the opening on the side near the transfer chamber 14.

[0058] In an optional embodiment, the inlet / outlet chamber 12 is provided with a carbon dioxide inlet end 11 and a carbon dioxide outlet end 15. The carbon dioxide inlet end 11 is connected to the lower cavity of the guide plate 2, and the carbon dioxide outlet end 15 is connected to the upper cavity of the guide plate 2.

[0059] It should be noted that after carbon dioxide enters the lower cavity of the diversion plate 2 from the carbon dioxide inlet end 11, it passes through the heat exchange tube 18 located at the lower part of the heating cavity 13, the transfer cavity 14, the heat exchange tube 18 located at the upper part of the heating cavity 13, and the upper cavity of the diversion plate 2 in sequence, and is then discharged from the carbon dioxide outlet end 15.

[0060] In an optional embodiment, a pressure relief valve and a temperature sensor are also provided on the pipe connecting the carbon dioxide inlet 11 to the carbon dioxide storage tank, and a shut-off valve and a temperature sensor are also provided on the pipe connecting the carbon dioxide outlet 15 to the extraction vessel 5.

[0061] In an optional embodiment, a partition 19 is provided between the inlet / outlet chamber 12 and the heating chamber 13, and between the transfer chamber 14 and the heating chamber 13, and a heat exchange tube 18 passes through the partition 19.

[0062] In an optional embodiment, the end of the air guide plate 4 is fixed to the partition plate 19 or the diversion plate 2.

[0063] In an optional embodiment, the air guide plate 4 is an arc-shaped plate, with the end of the air guide plate 4 near the inlet / outlet chamber 12 being higher than the end near the transfer chamber 14.

[0064] In an optional embodiment, the inner wall of the vertical channel between the vent 22 and the heat exchange tube mounting hole 21 is provided with a flow guiding structure. The flow guiding structure is spiral or strip-shaped protrusion, which can guide the steam to form a rotating flow in the channel and enhance the contact effect between the steam and the outer wall of the shaped tube 3. The inner diameter of the exhaust hole 23 is larger than the inner diameter of the vertical channel, and the outlet direction of the exhaust hole 23 is towards the area above the guide plate 4, so that the steam passing through the exhaust hole 23 can directly act on the condensate above the guide plate 4 to help remove the condensate on the outer wall of the shaped tube 3.

[0065] Furthermore, a sealing ring 191 is provided at the penetration point between the partition 19 and the heat exchange tube 18. The sealing ring 191 is made of an elastic material that is resistant to high steam temperature and anti-aging. The inner ring of the sealing ring 191 is tightly fitted with the outer wall of the heat exchange tube 18 to form a radial seal, and the outer ring is interference-fitted with the inner wall of the through hole on the partition 19 to form a circumferential seal. The connection position between the flow guide plate 2 and the inner wall of the heating chamber 13 adopts a full circumferential sealing structure. A high-temperature resistant sealing adhesive layer 24 is provided at the connection point. The sealing adhesive layer 24 covers the gap between the flow guide plate 2 and the inner wall of the heating chamber 13 to prevent steam from leaking from the connection gap.

[0066] Furthermore, the outer wall of the heating cavity 13 is wrapped with an insulation layer. The insulation layer is made of a low thermal conductivity insulating material, which can block the heat exchange between the heating cavity 13 and the external environment. A protective structure is provided on the outside of the insulation layer. The protective structure is made of a corrosion-resistant metal material with a certain mechanical strength, forming a protective enclosure for the insulation layer. A temperature detection interface is provided on the protective structure. The position of the temperature detection interface corresponds to the middle area of ​​the heating cavity 13, which is used to install a temperature detection element to monitor the real-time temperature inside the heating cavity 13.

[0067] Furthermore, the temperature sensors at the carbon dioxide inlet 11 and the carbon dioxide outlet 15 are both connected to the controller 6. The controller 6 can receive the temperature data transmitted by the two temperature sensors and calculate the temperature difference. The steam inlet 16 is equipped with a flow regulating component, which is electrically connected to the controller 6. The controller 6 can automatically adjust the opening and closing degree of the flow regulating component according to the calculated temperature difference, thereby adjusting the steam intake volume and maintaining the temperature difference between the carbon dioxide inlet and outlet within a preset range.

[0068] It should be noted that in actual production, the temperature of carbon dioxide after depressurization is between 28-34 degrees Celsius, and it needs to be heated to 46-50 degrees Celsius through a heat exchanger. In order to avoid the saturated steam heating rate being too fast, which would cause the carbon dioxide to heat up too quickly and exceed the preset value, the following two methods can be used to solve this problem. First, by speeding up the rate at which carbon dioxide passes through the heat exchanger, the residence time of carbon dioxide in the heat exchanger is reduced, thereby reducing the heating time. Second, by reducing the steam temperature or reducing the steam introduction rate, the rapid temperature rise can be avoided.

[0069] It should be noted that the heat exchanger of this application, by setting the combined structure of the flow guide plate 2, the irregular tube 3 and the air guide plate 4, can effectively reduce the problem of uneven heating caused by the application of steam heat exchangers in heating the extraction medium carbon dioxide.

[0070] Furthermore, the obtuse angle of the triangular boss 31 is set to 120°-150°. The triangular boss 31 can effectively increase the surface area of ​​the irregular tube 3 (compared to the structure without a boss, the surface area can be increased by 20% to 30%), improve the heat exchange efficiency, and make it easier for condensate to accumulate on the outer part of the boss, which is convenient for airflow to blow away. At the same time, at this angle, the flow resistance of steam on the surface of the irregular tube 3 is small, and it will not have an excessive impact on the overall steam flow.

[0071] The triangular protrusion within this angle range increases the contact area between the irregularly shaped tube and the steam by 25%-30% compared to a smooth tube. This not only improves the heat exchange rate but also reduces the amount of condensate adhering to the outer wall of the tube by 50% through the flow guiding and film breaking effects of the protrusion. This significantly reduces the obstruction of the heat exchange of carbon dioxide inside the tube by the heat insulation layer formed by the condensate. It is especially suitable for the process requirements of carbon dioxide in tobacco extraction, which requires precise heating to 46-50℃, thus avoiding the extension of the extraction cycle due to insufficient heat exchange efficiency.

[0072] Furthermore, the air guide plate 4 is fixed to the heating chamber 13 by a combination of welding and sealant. First, the end of the air guide plate 4 is welded to the partition plate 19 or the diversion plate 2 to ensure the stability of the connection. Argon arc welding is used to ensure sufficient strength. Then, high-temperature resistant sealant (such as silicone sealant, with a temperature range of -60℃ to 300℃) is applied to the weld to prevent steam leakage from the connection gap and improve the airtightness of the heat exchanger.

[0073] Furthermore, polyurethane foam is selected as the insulation layer material. The thickness of the insulation layer is determined based on the outer wall temperature of the heating cavity 13 and the ambient temperature. Additionally, an aluminum foil reflective film is placed between the insulation layer and the outer wall of the heating cavity 13 to further improve the insulation effect.

[0074] Further improvements were made to the controller 6's control logic: the preset temperature difference range was defined as ±2℃, meaning that when the temperature difference between the carbon dioxide inlet 11 and the outlet 15 exceeds 4℃ or falls below 0℃, the controller 6 activates the adjustment function. The adjustment response time is set to 5s to 10s to ensure timely adjustment of the steam intake and maintain a stable temperature difference. Simultaneously, a temperature alarm function was added. When the temperature at the carbon dioxide inlet 11 exceeds 36℃ or falls below 26℃, or the temperature at the outlet 15 exceeds 52℃ or falls below 44℃, the controller 6 issues an alarm signal and automatically shuts off the flow regulation component at the steam inlet 16 to prevent abnormal temperatures from damaging the heat exchanger and the tobacco extraction process.

[0075] This control logic works synergistically with the structural improvements of the heat exchanger. To meet the stringent requirements of 28-34℃ for the carbon dioxide inlet temperature and 46-50℃ for the outlet temperature in tobacco extraction, the steam intake is adjusted through temperature difference feedback. This keeps the fluctuation range of the carbon dioxide outlet temperature within ±0.8℃, which is significantly improved compared to the ±2.5℃ fluctuation accuracy of traditional heat exchangers. At the same time, the exhaust port helps to remove condensate, further reducing the impact of condensate on the heat exchange of carbon dioxide inside the tube, thus ensuring the stability and consistency of the extraction of effective tobacco components (such as solanesol and polyphenols).

[0076] Furthermore, the heat exchange tubes 18 (including the irregular tubes 3) are made of stainless steel.

[0077] Furthermore, a pressure sensor is installed on the heating chamber 13, and the pressure sensor establishes a signal connection with the controller 6 to monitor the pressure inside the heating chamber 13 in real time. When the pressure inside the heating chamber 13 exceeds the preset value, the controller 6 automatically opens the safety valve installed on the heating chamber 13 to release the pressure inside the chamber and prevent damage to the heating chamber 13 due to excessive pressure; when the pressure is lower than the preset value, the controller 6 issues an alarm signal to remind the operator to check the steam supply system to ensure that the pressure inside the heating chamber 13 is maintained within the normal range.

[0078] Furthermore, a condensate collection tank is provided at the bottom of the heating chamber 13, corresponding to the drain hole 41, to collect the condensate discharged from the drain hole 41. The condensate collection tank is connected to the steam outlet 17.

[0079] Example 2:

[0080] The difference between this implementation and Example 1 is that the triangular protrusions 31 are arranged in a spiral array on the outer wall of the shaped tube 3, and the spacing between two adjacent triangular protrusions 31 is uniform, forming a continuous flow channel; the long side 311 of the triangular protrusion 31 forms a certain angle with the axial direction of the shaped tube 3, and the direction of this angle is consistent with the direction of steam flow, reducing the resistance of steam when it flows through the protrusion; the surface of the triangular protrusion 31 is treated with anti-scaling to reduce the adhesion of condensate on the protrusion surface and further reduce the probability of water film formation.

[0081] In summary, this steam heat exchanger for tobacco extraction, by installing an odd number of guide plates 2 inside the heating chamber 13, with vent holes 22 on the guide plates 2 for small-scale air passage, and a guide plate 4 at the bottom of the heat exchange tube 18, firstly, the condensed gas in the heating chamber 13 will accumulate at the bottom. The guide plates 2 disperse the newly entering steam and reduce the temperature difference between the top and bottom of the heating chamber 13. Secondly, the guide plate 4 wraps the downward-rushing new steam around the outside of the heat exchange tube 18, thus reducing the temperature difference at the bottom. The condensate adhering to the heat exchange tube 18 is removed. Finally, the method of setting vent holes 22 on the guide plate 2 can be applied to a variety of heat exchange modes. When high-velocity low-temperature steam is introduced, the temperature difference between the steam and carbon dioxide is small, and the steam is easy to condense. At this time, most of the steam moves along the S-shaped path formed by the guide plate 2, which improves the removal efficiency of condensate. When low-velocity high-temperature steam is introduced, the temperature difference between the steam and carbon dioxide is large, and the steam is not easy to condense. At this time, most of the steam passes through the vent holes 22 and spreads in the heating chamber 13.

[0082] The steam heat exchanger for tobacco extraction features a uniform array of triangular protrusions 31 on the surface of the shaped tube 3, with one side of the long side 311 facing the direction from which the steam comes. First, the obtuse angle structure of the long side 311 and the short side 312 increases the surface area of ​​the shaped tube 3, enhancing the heat exchange efficiency between carbon dioxide and steam inside the tube 3 and preventing the formation of a continuous water film on the surface of the tube 3. Second, condensate is more likely to accumulate on the protruding parts of the long side 311 and the short side 312, making it easier to be blown away by the airflow. Furthermore, condensate is less likely to accumulate in the concave parts of the long side 311 and the short side 312, which are the closest to the inner wall of the shaped tube 3, reducing the impact of condensate on the carbon dioxide inside the tube. Finally, the long side 311 facing the direction from which the steam comes increases the efficiency of the airflow in removing condensate.

[0083] This steam heat exchanger for tobacco extraction uses a vertical channel to connect the vent 22 with the heat exchange tube mounting hole 21, and the heat exchange tube mounting hole 21 with the exhaust hole 23. First, it improves the ventilation efficiency in the heat exchange tube mounting hole 21, avoiding the low heat exchange efficiency of the irregular tube 3 located in the heat exchange tube mounting hole 21. It also avoids the accumulation of condensate between the outside of the irregular tube 3 and the heat exchange tube mounting hole 21 due to the triangular boss 31 structure. Second, the exhaust hole 23 connects the two sections of the air guide plate 4, accelerating the water removal efficiency of the airflow on the next section of the air guide plate 4. It can also use the airflow of the air guide plate 4 to accelerate the steam flow rate in the heat exchange tube mounting hole 21.

[0084] This steam heat exchanger for tobacco extraction, by setting the vent 22 to a funnel shape, can guide a portion of the steam passing through the vent 22 into the heat exchange tube mounting hole 21, and can also accelerate the flow rate of the steam after passing through the vent 22.

[0085] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A steam heat exchanger for tobacco extraction, comprising an inlet / outlet chamber (12), a heating chamber (13), and a transfer chamber (14), wherein the inlet / outlet chamber (12) and the transfer chamber (14) are connected by a heat exchange tube (18), the inlet / outlet chamber (12) is divided into upper and lower chambers by a layered plate (121), the heat exchange tube (18) passes through the heating chamber (13), and the heating chamber (13) is provided with a steam inlet end (16) near one end and a steam outlet end (17) near the other end, respectively, characterized in that: The heating chamber (13) is provided with at least three diversion plates (2) arranged alternately in an odd number. The diversion plate (2) closest to the inlet / outlet chamber (12) and the diversion plate (2) closest to the transfer chamber (14) are both located at the top of the heating chamber (13). The steam inlet end (16) is located between the diversion plate (2) closest to the inlet / outlet chamber (12) and the inlet / outlet chamber (12). The steam outlet end (17) is located between the diversion plate (2) closest to the transfer chamber (14) and the transfer chamber (14). The diversion plate (2) is provided with a heat exchange tube mounting hole (21) for passing through the heat exchange tube (18) and a vent hole (22) for slow ventilation. A guide plate (4) is provided at the bottom of the heat exchange tube (18) located in the lower part of the heating chamber (13). The guide plate (4) is parallel to the heat exchange tube (18) and there is a gap between it and the heat exchange tube (18). A drain hole (41) is provided at the tail of the guide plate (4) in the area between the two diversion plates (2). The heat exchange tube (18) located at the bottom of the heating chamber (13) is configured as a shaped tube (3). The outer wall of the shaped tube (3) is provided with a horizontally uniform array of triangular protrusions (31). The cross section of the triangular protrusion (31) is triangular. In addition to the side closest to the inside of the shaped tube (3), the triangular cross section of the triangular protrusion (31) also includes a long side (311) and a short side (312). The included angle between the long side (311) and the short side (312) is an obtuse angle. The long side (311) faces the side close to the inlet / outlet chamber (12), and the short side (312) faces the side close to the transfer chamber (14).

2. The steam heat exchanger for tobacco extraction according to claim 1, characterized in that, On the flow guide plate (2) located at the bottom of the heating chamber (13), the vent hole (22) is set above the heat exchange tube mounting hole (21) for passing through the shaped tube (3). The vent hole (22) and the heat exchange tube mounting hole (21) are connected by a vertical channel. The flow guide plate (2) is also provided with an exhaust hole (23) below the heat exchange tube mounting hole (21) for passing through the shaped tube (3). The exhaust hole (23) passes through both sides of the flow guide plate (2). The heat exchange tube mounting hole (21) and the corresponding exhaust hole (23) are connected by a vertical channel. The lowest point of the exhaust hole (23) is higher than or level with the air guide plate (4).

3. A steam heat exchanger for tobacco extraction according to claim 2, characterized in that, On the flow guide plate (2) located at the bottom of the heating chamber (13), the vent (22) is configured in the shape of a horn, and the opening of the vent (22) on the side near the inlet / outlet chamber (12) is larger than the opening on the side near the transfer chamber (14).

4. A steam heat exchanger for tobacco extraction according to claim 3, characterized in that, The feed inlet / outlet chamber (12) is provided with a carbon dioxide inlet end (11) and a carbon dioxide outlet end (15). The carbon dioxide inlet end (11) is connected to the lower cavity of the guide plate (2), and the carbon dioxide outlet end (15) is connected to the upper cavity of the guide plate (2).

5. A steam heat exchanger for tobacco extraction according to claim 4, characterized in that, A pressure relief valve and a temperature sensor are also installed on the pipe connecting the carbon dioxide inlet (11) to the carbon dioxide storage tank, and a shut-off valve and a temperature sensor are also installed on the pipe connecting the carbon dioxide outlet (15) to the extraction vessel (5).

6. A steam heat exchanger for tobacco extraction according to claim 3, characterized in that, A partition (19) is provided between the inlet / outlet chamber (12) and the heating chamber (13), and between the transfer chamber (14) and the heating chamber (13). The heat exchange tube (18) passes through the partition (19).

7. A steam heat exchanger for tobacco extraction according to claim 6, characterized in that, The end of the air guide plate (4) is fixed to the partition plate (19) or the diversion plate (2).

8. A steam heat exchanger for tobacco extraction according to claim 3, characterized in that, The air guide plate (4) is an arc-shaped plate, and the end of the air guide plate (4) near the inlet / outlet chamber (12) is higher than the end near the transfer chamber (14).

9. A steam heat exchanger for tobacco extraction according to claim 3, characterized in that, The vertical channel between the vent (22) and the heat exchange tube mounting hole (21) is provided with a flow guiding structure. The flow guiding structure is spiral or strip-shaped protrusion, which can guide the steam to form a rotating flow in the channel and enhance the contact effect between the steam and the outer wall of the shaped tube (3). The inner diameter of the exhaust hole (23) is larger than the inner diameter of the vertical channel, and the outlet direction of the exhaust hole (23) is towards the area above the air guide plate (4), so that the steam passing through the exhaust hole (23) can directly act on the condensate above the air guide plate (4) to help remove the condensate on the outer wall of the shaped tube (3).

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