Sealing structure of supercritical extraction equipment

Abstract

The utility model relates to a sealing structure of supercritical extraction equipment, which comprises a reaction kettle, the outer end of the reaction kettle is sleeved with an end cover, the bottom end of the end cover is fixedly connected with a fixing ring, the outer end of the fixing ring is provided with a sealing groove, the inner wall of the sealing groove is rotatably connected with a sealing ring, and the bottom end of the fixing ring is fixedly connected with a movable sealing assembly. According to the structure, the elastic corrugated sealing ring, the sealing ring and the movable sealing assembly are adopted to form multiple sealing, the movable sealing assembly is matched with the pressurizing ring through the first annular cavity and the second annular cavity, the sealing force is automatically adjusted through system pressure, heat-absorbing expansion liquid in the liquid storage ring can automatically compensate for a heat-expansion and cold-contraction gap, and meanwhile the sealing effect is improved. The piezoelectric ceramic stack is combined with the stirring rod, ultrasonic-mechanical coupling extraction is achieved, mass transfer efficiency is improved, crystals on a sealing component can be removed through the generated cavitation effect, and the ultrasonic-mechanical coupling extraction device has the advantages of being reliable in sealing, high in self-adaptability and the like.

Description

Technical Field

[0001] The sealing structure for supercritical extraction equipment involved in the present utility model particularly relates to a sealing structure for a supercritical extraction equipment applied in the technical field of extraction devices. Background Art

[0002] Due to its environmental protection and high efficiency characteristics, the supercritical CO2 extraction technology has been widely applied in the fields of medicine, food, fine chemical industry, etc. The extraction tank, as the core equipment, usually needs to withstand a high pressure of 20 - 30 MPa during operation, and the working temperature range is 40 - 80 °C. As the most frequently opened part of the equipment, the sealing system of the extraction tank end cover faces special technical challenges.

[0003] Conventional O - rings, gaskets, etc. are prone to deformation and damage during frequent opening. Dynamic mechanical seals and packing seals have large frictional losses in high - pressure environments. At the same time, supercritical CO2 has extremely strong solubility, which easily causes the aging of sealing materials, and frequent opening and closing cause mechanical damage to the sealing surface.

[0004] The specification of the Chinese utility model patent CN 218031893U discloses a sealing structure for a supercritical extraction equipment. The present utility model has the advantage of good sealing effect. During actual use, through the coordinated use of a transmission pipe, a feeding pipe, a sealing block, and a spring, the purpose of good sealing effect can be achieved, preventing leakage during the discharging process of the supercritical extraction equipment, reducing the waste of raw materials, saving costs, and improving the practicability of the supercritical extraction equipment. Although the above design solves the basic leakage problem of the extraction equipment, the sealing depends on mechanical pressure, cannot cope with severe pressure fluctuations, and the sealing parts are prone to wear.

[0005] The specification of the Chinese utility model patent CN 216879285U discloses a reaction kettle for supercritical extraction. After the upper docking plate and the lower docking plate of the device are docked, a multi - prism cylinder structure is formed, and a flexible sealing plate is correspondingly and tightly installed on each side. The flexible sealing plate uses a rigid support plate as a bearing part. Through this setting, the flexible sealing plate can be more evenly stressed, enabling the flexible sealing plate to better seal the second docking seam. Although the above design makes the flexible sealing plate more evenly stressed and better sealed, the sealing material is prone to aging, and maintenance requires complete disassembly.

[0006] Therefore, through this technical solution, we solve the problems of easy wear of the seal, easy damage of the mechanical seal, and poor sealing effect existing in the prior art. Summary of the Utility Model

[0007] In view of the above-mentioned prior art, the technical problem to be solved by the present utility model is to provide a sealing structure for a supercritical extraction device, which can automatically adjust the sealing force under high-pressure environment, automatically adjust the sealing force with the change of pressure, compensate for the gap caused by temperature change, reduce mechanical damage during the installation process, and extend the service life of the sealing structure.

[0008] To solve the above problems, the present utility model provides a sealing structure for a supercritical extraction device, including a reaction kettle, the outer end of the reaction kettle is sleeved with an end cover, the bottom end of the end cover is fixedly connected with a fixed ring, the outer end of the fixed ring is provided with a sealing groove, the inner wall of the sealing groove is rotatably connected with a sealing ring, the bottom end of the fixed ring is fixedly connected with a movable sealing component, the movable sealing component includes a first annular cavity fixedly connected with the bottom end of the fixed ring, the bottom end of the first annular cavity is fixedly connected with a liquid storage ring, the first annular cavity and the liquid storage ring are communicated with each other, the inside of the liquid storage ring is filled with a heat-absorbing expansion liquid, the inner wall of the first annular cavity is fixedly connected with a first retaining ring, the inner wall of the first annular cavity is slidably connected with a first pressure-increasing ring, the inner end of the opening of the first annular cavity is fixedly connected with a second annular cavity, the inner wall of the second annular cavity is fixedly connected with a second retaining ring, the inner wall of the liquid storage ring is slidably connected with a second pressure-increasing ring, the first annular cavity is communicated with the second annular cavity, the bottom end of the end cover is fixedly connected with a elastic corrugated sealing ring, and the bottom end of the elastic corrugated sealing ring is fixedly connected with an elastic ring.

[0009] As a further improvement of the present application, a bearing is fixedly connected to the inner wall of the fixed ring, the inner end of the bearing is fixedly connected with a vibration cavity), the inner end of the vibration cavity is fixedly connected with a plurality of piezoelectric ceramic stacks, and the plurality of piezoelectric ceramic stacks are distributed in a circumferential array. The setting of the bearing provides stable support, ensuring the rotation accuracy and operation stability of the vibration cavity. The piezoelectric ceramic stacks are distributed in a circumferential array, and the generated ultrasonic waves can be evenly transmitted into the reaction kettle.

[0010] As a further improvement of the present application, the bottom ends of the plurality of piezoelectric ceramic stacks are all fixedly connected with stirring rods, and the stirring rods penetrate through the vibration cavity and extend into the reaction kettle. The top end of the vibration cavity is fixedly connected with a stirring motor through an input shaft, and the input shaft penetrates through the end cover and is rotatably connected with the end cover. The cavitation effect generated by ultrasonic vibration destroys the boundary layer, and mechanical stirring increases the contact area between the material and carbon dioxide, improves the mass transfer rate of the target substance, shortens the extraction time, and ultrasonic waves can also break the cell wall and accelerate the release of active ingredients.

[0011] As a further improvement of the present application, the endothermic expansion liquid in the liquid storage ring is a mixed solution of glycerol and water with a volume ratio of 3:1, and it has a linear expansion characteristic within the temperature range of 40 - 80 °C. The mixed solution of glycerol and water has good linear expansion characteristics, ensuring the stability of the sealing pressure. The ratio of 3:1 optimizes the physical properties of the solution, enabling it to remain stable within the operating temperature range. The volume change caused by temperature changes can compensate for the sealing gap, improving the sealing effect. The solution is non-toxic and harmless, and even if it leaks, it will not contaminate the product.

[0012] As another improvement of the present application, the piezoelectric ceramic stack is made of piezoelectric ceramic material, and a protective housing is provided outside it. An elastic buffer layer is provided between the protective housing and the vibration cavity, and the power supply end of the piezoelectric ceramic stack is electrically connected to an external control system through a wire. The elastic buffer layer reduces the vibration transmitted to the outer shell, reducing component fatigue. The electrical connection between the wire and the external control system facilitates the adjustment and control of vibration parameters, and the overall structure improves the service life and reliability of the piezoelectric ceramic stack.

[0013] As a supplement to another improvement of the present application, an arc-shaped groove is provided on the inner wall of the reaction kettle. The cross-section of the arc-shaped groove is a semi-circular structure, and the protruding part of the liquid storage ring matches the arc-shaped groove. The design of the arc-shaped groove increases the sealing area, improves the sealing effect, and enhances the reliability and stability of the seal.

[0014] In summary, the present solution has the following beneficial effects:

[0015] (1) Multiple active seals; A three-seal structure is adopted. The first seal is achieved through the elastic corrugated seal ring and the elastic ring at the bottom end of the end cover. When installed, these two components are compressed and expanded, coming into close contact with the inner wall of the reaction kettle and the outer wall of the end cover. The second seal is composed of the sealing ring in the fixed ring coming into close contact with the inner wall of the reaction kettle. The third seal is achieved through the nesting of the liquid storage ring and the arc-shaped groove on the inner wall of the reaction kettle. The three seals indirectly form a labyrinth seal structure, improving the overall sealing performance.

[0016] (2) Pressure self-enhanced seal; When the reaction kettle is pressurized, the high-pressure gas pushes the second pressure-increasing ring to slide upward along the second annular cavity, compressing the gas pre-filled in the cavity. The compressed gas then pushes the first pressure-increasing ring to move downward along the first annular cavity, compressing the endothermic expansion liquid in the liquid storage ring. This structural design makes the seal between the liquid storage ring and the arc-shaped groove tighter as the system pressure increases, achieving pressure self-enhanced sealing.

[0017] (3) Temperature compensation seal; The liquid storage ring is filled with a mixed solution of glycerol and water with a volume ratio of 3:1 as the endothermic expansion liquid. This solution has a linear expansion characteristic within the temperature range of 40 - 80 °C. When the temperature inside the reaction kettle rises, the endothermic expansion liquid automatically expands, further enhancing the sealing effect between the liquid storage ring and the arc-shaped groove, effectively compensating for the influence brought by temperature changes.

[0018] (4) Ultrasonic-mechanical coupling extraction: The stirring motor drives the vibration cavity to rotate through the input shaft, and then drives multiple stirring rods to rotate for mechanical stirring. At the same time, the piezoelectric ceramic stacks distributed in a circumferential array generate ultrasonic waves, which are transmitted into the reaction kettle through the stirring rods. A protective housing and an elastic buffer layer are provided outside the piezoelectric ceramic stacks, ensuring the reliable operation of the ultrasonic vibration system.

[0019] (5) Self-cleaning and anti-crystallization: The ultrasonic waves generated by the piezoelectric ceramic stacks are transmitted into the reaction kettle through the stirring rods, forming cavitation bubbles in the fluid. The shock waves and microjets generated by the rupture of these cavitation bubbles can effectively remove the crystallized substances on the sealing mechanisms such as the liquid storage ring and the second annular cavity. The setting of the protective housing and the elastic buffer layer ensures the continuous and stable operation of this self-cleaning function and extends the service life of the sealing device. Description of the Drawings

[0020] Figure 1 is the overall structural schematic diagram of the present application;

[0021] Figure 2 is the first partial view of the present application;

[0022] Figure 3 is the second partial view of the present application;

[0023] Figure 4 is the exploded view of the present application;

[0024] Figure 5 is the front view of the present application;

[0025] Figure 6 of the present application Figure 5 is the A-A cross-sectional view;

[0026] Figure 7 of the present application Figure 6 is the B-B cross-sectional view;

[0027] Figure 8 of the present application Figure 6 is the enlarged view at C;

[0028] Figure 9 is the installation schematic diagram of the present application.

[0029] Description of the reference numerals in the drawings:

[0030] 1. Reactor; 2. End cover; 3. Fixed ring; 4. Sealing groove; 5. Sealing ring; 6. First annular cavity; 7. Liquid storage ring; 8. Heat-absorbing expansion liquid; 9. First retaining ring; 10. First pressure-increasing ring; 11. Second annular cavity; 12. Second retaining ring; 13. Second pressure-increasing ring; 14. Elastic corrugated sealing ring; 15. Elastic ring; 16. Bearing; 17. Vibration cavity; 18. Piezoelectric ceramic stack; 19. Stirring rod; 20. Stirring motor; 21. Protective housing. Specific embodiments

[0031] The following will describe two embodiments of the present application in detail with reference to the accompanying drawings.

[0032] The first embodiment:

[0033] Figures 1-9 A sealing structure of a supercritical extraction device is shown, including a reactor 1. An end cover 2 is sleeved on the outer end of the reactor 1. A fixed ring 3 is fixedly connected to the bottom end of the end cover 2. A sealing groove 4 is opened on the outer end of the fixed ring 3. A sealing ring 5 is rotatably connected to the inner wall of the sealing groove 4. A movable sealing assembly is fixedly connected to the bottom end of the fixed ring 3. The movable sealing assembly includes a first annular cavity 6 fixedly connected to the bottom end of the fixed ring 3. A liquid storage ring 7 is fixedly connected to the bottom end of the first annular cavity 6. The first annular cavity 6 and the liquid storage ring 7 are in communication with each other. A heat-absorbing expansion liquid 8 is filled in the interior of the liquid storage ring 7. A first retaining ring 9 is fixedly connected to the inner wall of the first annular cavity 6. A first pressure-increasing ring 10 is slidably connected to the inner wall of the first annular cavity 6. The inner end of the opening of the first annular cavity 6 is fixedly connected to a second annular cavity 11. A second retaining ring 12 is fixedly connected to the inner wall of the second annular cavity 11. A second pressure-increasing ring 13 is slidably connected to the inner wall of the liquid storage ring 7. The first annular cavity 6 is in communication with the second annular cavity 11. An elastic corrugated sealing ring 14 is fixedly connected to the bottom end of the end cover 2. An elastic ring 15 is fixedly connected to the bottom end of the elastic corrugated sealing ring 14.

[0034] The heat-absorbing expansion liquid 8 in the liquid storage ring 7 is a mixed solution of glycerol and water, with a volume ratio of 3:1, and has a linear expansion characteristic within the temperature range of 40 - 80 °C.

[0035] An arc-shaped groove is opened on the inner wall of the reactor 1. The cross-section of the arc-shaped groove is a semi-circular structure. The convex part of the liquid storage ring 7 is matched with the arc-shaped groove.

[0036] When the reactor 1 is used to perform supercritical extraction on the material, the entire end cover 2 is connected to the outer end of the reactor 1 in a sleeve-type manner. During the sleeve-type process, the elastic corrugated sealing ring 14 and the elastic ring 15 are pressurized and expanded, and the elastic corrugated sealing ring 14 and the elastic ring 15 are in close contact with the inner wall of the reactor 1 and the outer wall of the end cover 2 at the same time, so as to realize the primary sealing of the reactor 1 and the end cover 2. At the same time, the multiple wave peaks of the elastic corrugated sealing ring 14 are in close contact with the inner wall of the reactor 1 and the outer wall of the end cover 2, so as to further enhance the sealing performance of the device. The elastic corrugated sealing ring 14 and the elastic ring 15 are in a contracted state when the reactor 1 is not installed, and they expand only when installed, so as to avoid the elastic corrugated sealing ring 14 and the elastic ring 15 from being subjected to hard friction and reducing the service life. At the same time, the sealing ring 5 in the fixing ring 3 is in close contact with the inner wall of the reactor 1 to form a second seal. After the installation is completed, when the reactor 1 is running and pressurized, the high-pressure gas in the reactor 1 pushes the second booster to increase the pressure. The pressure ring 13 slides upward along the inner wall of the second annular cavity 11, and the second booster ring 13 compresses the gas pre-filled in the second annular cavity 11. The compressed gas in the second annular cavity 11 further pushes the first booster ring 10 to move downward along the inner wall of the first annular cavity 6, and the first booster ring 10 compresses the endothermic expansion liquid 8 filled in the liquid storage ring 7. After the endothermic expansion liquid 8 is pressurized, the liquid storage ring 7 is closely contacted with the arc groove of the inner wall of the reactor 1. The greater the pressure in the reactor 1, the stronger the seal. When the temperature in the reactor 1 increases, the expansion of the endothermic expansion liquid 8 will further enhance the seal, thereby forming a third active seal, which can also be better sealed when facing pressure fluctuations, and will not rub against the inner wall of the reactor 1 during installation. The first seal is used to seal the outer wall of the reactor 1 and the inner wall of the end cover, and the second and third seals both seal the inner wall of the reactor 1. The first seal, the second seal, and the third seal indirectly form a labyrinth seal, which makes the sealing better.

[0037] The second implementation method:

[0038] Figures 1-9 It is shown that on the basis of the first embodiment, the inner wall of the fixed ring 3 is further fixedly connected to a bearing 16, the inner end of the bearing 16 is fixedly connected to a vibration cavity 17, and the inner end of the vibration cavity 17 is fixedly connected to a plurality of piezoelectric ceramic stacks 18, which are distributed in a circular array.

[0039] The bottom ends of the multiple piezoelectric ceramic stacks 18 are fixedly connected to stirring rods 19, and the stirring rods 19 extend through the vibration cavity 17 into the reactor 1. The top of the vibration cavity 17 is fixedly connected to a stirring motor 20 via an input shaft, and the input shaft passes through the end cover 2 and is rotatably connected to the end cover 2.

[0040] The piezoelectric ceramic stack 18 is made of piezoelectric ceramic material, and a protective housing 21 is provided outside it. An elastic buffer layer is provided between the protective housing 21 and the vibration cavity 17, and the power supply end of the piezoelectric ceramic stack 18 is electrically connected to an external control system through a wire.

[0041] During material extraction, the stirring motor 20 is started. The stirring motor 20 drives the vibration cavity 17 to rotate, and the vibration cavity 17 drives a plurality of stirring rods 19 to rotate to stir the material. At the same time, the control system controls the piezoelectric ceramic stack 18 to vibrate to generate ultrasonic waves. The ultrasonic waves are transmitted to the inside of the reaction kettle 1 through the stirring rods 19 and act on the material. When ultrasonic waves propagate in a fluid, cavitation bubbles are generated. The rupture of these cavitation bubbles will generate shock waves and microjets, thereby effectively removing the crystals attached to the sealing mechanisms such as the liquid storage ring 7 and the second annular cavity 11, forming a self-cleaning effect, effectively preventing the continuous accumulation of crystals, prolonging the service life of the sealing device, ensuring a stable sealing effect. The ultrasonic waves achieve the ultrasonic-mechanical coupling effect. The ultrasonic waves destroy the cell wall structure of the material through the cavitation effect, and at the same time, the mechanical stirring provides macroscopic material movement. The two work together to accelerate the precipitation of active substances and improve the mass transfer efficiency. This coupling effect also optimizes the process parameters, enabling the extraction process to be carried out at a lower temperature, not only reducing the consumption of CO2, but also shortening the extraction time and effectively reducing the energy consumption.

[0042] Combined with the current actual requirements, the above-mentioned implementation manner adopted in this application, the protection scope is not limited thereto. Within the knowledge scope of those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of this utility model.

Claims

1. A sealing structure of a supercritical extraction device, comprising a reaction kettle (1), characterized in that: A cover (2) is sleeved on the outer end of the reactor (1). A fixing ring (3) is fixedly connected to the bottom end of the cover (2). A sealing groove (4) is formed in the outer end of the fixing ring (3). A sealing ring (5) is rotatably connected to the inner wall of the sealing groove (4). An active sealing assembly is fixedly connected to the bottom end of the fixing ring (3). The active sealing assembly includes a first annular cavity (6) fixedly connected to the bottom end of the fixing ring (3). A liquid storage ring (7) is fixedly connected to the bottom end of the first annular cavity (6). The first annular cavity (6) and the liquid storage ring (7) communicate with each other. An endothermic expansion liquid (8) is filled in the liquid storage ring (7). A first retaining ring (9) is fixedly connected to the inner wall of the first annular cavity (6). A first pressure increasing ring (10) is slidably connected to the inner wall of the first annular cavity (6). A second annular cavity (11) is fixedly connected to the inner end of the opening of the first annular cavity (6). A second retaining ring (12) is fixedly connected to the inner wall of the second annular cavity (11). A second pressure increasing ring (13) is slidably connected to the inner wall of the liquid storage ring (7). The first annular cavity (6) and the second annular cavity (11) communicate with each other. A resilient corrugated sealing ring (14) is fixedly connected to the bottom end of the cover (2). A resilient ring (15) is fixedly connected to the bottom end of the resilient corrugated sealing ring (14).

2. The sealing structure of a supercritical extraction device according to claim 1, characterized in that: A bearing (16) is fixedly connected to the inner wall of the fixing ring (3). A vibration cavity (17) is fixedly connected to the inner end of the bearing (16). A plurality of piezoelectric ceramic stacks (18) are fixedly connected to the inner end of the vibration cavity (17). The plurality of piezoelectric ceramic stacks (18) are distributed in a circumferential array.

3. The sealing structure of a supercritical extraction device according to claim 2, characterized in that: A stirring rod (19) is fixedly connected to the bottom end of each of the plurality of piezoelectric ceramic stacks (18), and the stirring rod (19) penetrates through the vibration cavity (17) and extends into the reactor (1). A stirring motor (20) is fixedly connected to the top end of the vibration cavity (17) through an input shaft, and the input shaft penetrates through the cover (2) and is rotatably connected to the cover (2).

4. The sealing structure of a supercritical extraction device according to claim 1, wherein: The endothermic expansion liquid (8) in the liquid storage ring (7) is a mixed solution of glycerol and water, and its volume ratio is 3:1, and it has a linear expansion characteristic in the temperature range of 40 - 80 °C.

5. The sealing structure of a supercritical extraction device according to claim 2, wherein: The piezoelectric ceramic stack (18) is made of piezoelectric ceramic material. A protective housing (21) is provided outside it. An elastic buffer layer is provided between the protective housing (21) and the vibration cavity (17), and the power supply end of the piezoelectric ceramic stack (18) is electrically connected to an external control system through a wire.

6. The sealing structure of a supercritical extraction device according to claim 1, wherein: An arc-shaped groove is formed in the inner wall of the reactor (1). The cross-section of the arc-shaped groove is a semi-circular structure. The protruding part of the liquid storage ring (7) matches the arc-shaped groove.

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