A centrifugal membrane coupling device for tea liquor clarification and macromolecular taste substance enrichment

Abstract

The application discloses a centrifugal membrane coupling device for tea soup clarification and macromolecular taste substance enrichment and mainly relates to the field of tea deep processing and plant extraction equipment. The device comprises a shell, a liquid collecting tank is arranged at the top of the shell, a hollow rotating shaft is arranged in the shell, the rotating shaft is rotationally connected with the shell, a driving motor is closed connected with the bottom end of the rotating shaft, the top opening of the rotating shaft is communicated with the liquid collecting tank, a filter membrane assembly is arranged outside the rotating shaft, flow guide holes are formed in the side wall of the rotating shaft, a clear liquid outlet is arranged at the bottom of one side of the liquid collecting tank, a feeding inlet and a concentrated liquid outlet are respectively arranged at the bottom of the two sides of the shell. The device has the advantages that the adhering layer on the surface of the membrane can be dynamically removed, the membrane holes can be effectively prevented from being blocked, the tea soup clarification and the enrichment of macromolecular taste substances can be simultaneously realized in a single device, the whole process is carried out in a closed shell, the tea soup is prevented from directly contacting with air, the oxidation and browning risk of polyphenols is reduced, and the natural color and refreshing taste of the tea soup are maintained.

Description

Technical Field

[0001] This invention relates to the field of tea deep processing and plant extraction equipment, specifically a centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances. Background Technology

[0002] Currently, in the production process of instant tea powder and freeze-dried tea powder, the tea infusion extract typically contains a large amount of pectin, protein, and fine tea residue. To obtain a clear and transparent tea infusion, it is necessary to filter and separate the tea infusion to extract the clear tea liquid. Existing tea infusion extraction technologies mainly suffer from the following drawbacks: 1. Traditional filtration is prone to clogging: When processing high-concentration tea soup, existing plate and frame filters or static membrane filters tend to clog the membrane pores quickly because the colloidal substances (pectin) in the tea soup easily accumulate on the membrane surface to form a "filter cake layer" or "concentration polarization layer". This results in a sharp drop in flux, low production efficiency and difficulty in cleaning.

[0003] 2. Loss of key flavor compounds (resulting in a bland taste): To prevent clogging, current processes often have to use large-pore filtration or excessive centrifugation. This causes large molecules such as water-soluble tea polysaccharides and bonded glycosides, which originally provide "mellowness" and "sweetness" in the tea soup, to be removed as impurities. This directly results in the final freeze-dried tea powder having a rapid loss of aroma, a thin tea soup taste, and a lack of complexity when brewed.

[0004] 3. Risk of oxidation and deterioration: Traditional centrifugal separation equipment is mostly open structure. When the tea soup rotates at high speed, it comes into a lot of contact with air, which causes the heat-sensitive tea polyphenols and catechins to undergo enzymatic or non-enzymatic oxidation, making the tea soup darker in color (brown) and lose its fresh taste. Summary of the Invention

[0005] The purpose of this invention is to provide a centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances. It can dynamically "sweep away" the adhering layer on the membrane surface by rotating the rotating shaft at high speed, effectively preventing membrane pore blockage. It can also achieve tea infusion clarification and macromolecular flavor substance enrichment simultaneously in a single device, reducing equipment footprint and process steps. Moreover, the entire process is carried out in a sealed shell, avoiding direct contact between the tea infusion and air, reducing the risk of oxidation and browning of polyphenols, and helping to maintain the natural color and refreshing taste of the tea infusion.

[0006] To achieve the above objectives, the present invention employs the following technical solution: A centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances includes a sealed shell with a collection tank at the top and a hollow rotating shaft inside the shell. The rotating shaft extends through the upper and lower ends of the shell, respectively, and is dynamically sealed with a rotary sealing assembly at each end. The bottom of the rotating shaft is closed and connected to a drive motor, while the top of the rotating shaft is open and extends into the collection tank, communicating with it. A filter membrane assembly is fitted onto the outer side of the inner portion of the rotating shaft within the shell. Multiple guide holes are formed on the sidewall of the rotating shaft, allowing the original tea infusion inside the shell to be filtered by the filter membrane assembly and then enter the rotating shaft through the guide holes. An annular gap with a radial width of 10–30 mm is left between the outer edge of the filter membrane assembly and the inner wall of the shell, forming a macromolecular sedimentation channel. A clear liquid outlet is located at the bottom of one side of the collection tank, and a feed inlet and a concentrate outlet are located on both sides of the bottom of the shell.

[0007] Furthermore, the filter membrane assembly includes a plurality of circular membranes sequentially sleeved on a rotating shaft along the axial direction, the inner ring of the membranes being fixed to the outer side of the rotating shaft by a sealing ring and a clamping nut; each membrane has a flow guiding cavity inside, and the plurality of flow guiding holes correspond to and communicate with the plurality of flow guiding cavities respectively; a spacing of 5 to 10 mm is left between adjacent membranes.

[0008] Furthermore, a gas interface is provided on the top of the housing, through which an inert gas source is connected to maintain a slightly positive pressure inert atmosphere of 0.02 to 0.05 MPa inside the housing during device operation.

[0009] Furthermore, the drive motor is a variable frequency speed control motor, used to drive the rotating shaft and filter membrane assembly to rotate at a speed of 500 to 2000 r / min.

[0010] Furthermore, the bottom of the shell is provided with a conical concentration hopper, and the concentrate outlet is located at the bottom of the conical concentration hopper.

[0011] Furthermore, the bottom of the housing is provided with a hollow base, the drive motor is installed inside the base, and the rotating shaft is connected to the drive motor through a coupling.

[0012] Furthermore, the drive motor is started to rotate the filter membrane assembly and generate shear force; the pressure inside the housing is controlled to be slightly positive, so that the clear tea liquid passes through the membrane and enters the rotating shaft to be discharged upwards, while the large molecular flavor substances are enriched downwards along the sedimentation channel under the action of centrifugal force.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a rotating shaft to drive the filter membrane assembly to rotate at high speed. Centrifugal force is used to throw colloidal substances in the tea soup to the outside of the membrane, dynamically "sweeping away" the adhering layer on the membrane surface and preventing membrane pore blockage. This allows the device to significantly increase membrane flux and extend the operating cycle when processing tea soup with high pectin and high solids content, thereby improving work efficiency and making it easy to clean. At the same time, it avoids the situation where large molecules such as water-soluble tea polysaccharides and bonded glycosides that provide "mellowness" and "sweetness" in the tea soup are removed as impurities when using large-pore filtration, thus ensuring a good taste of freeze-dried powder after brewing.

[0014] 2. When the present invention is in operation, on the one hand, the clear tea liquid rises through the hollow part inside the rotating shaft to the collection tank for collection, and on the other hand, the concentrated tea liquid sinks outside the annular gap formed between the filter membrane assembly and the inner wall of the shell and is discharged through the concentrate outlet. This enables the present invention to achieve a bidirectional layered flow working mode, thereby enabling the clarification of tea liquid and the enrichment of macromolecular flavor substances in a single device, reducing the equipment footprint and separation process.

[0015] 3. The filtration and separation process of this invention is carried out entirely within a sealed shell, which can minimize the direct contact between the tea soup and the air under high temperature and high shear, thereby reducing the risk of oxidation and browning of polyphenols after contact with air, and helping to maintain the natural color and refreshing taste of the tea soup. Attached Figure Description

[0016] Appendix Figure 1 This is a structural cross-sectional view of the present invention.

[0017] The following are the reference numerals in the attached diagram: 1. Shell; 2. Collection tank; 3. Rotating shaft; 4. Drive motor; 5. Filter membrane assembly; 6. Flow guide hole; 7. Clear liquid outlet; 8. Feed inlet; 9. Concentrate outlet; 10. Membrane; 11. Flow guide cavity; 12. Gas interface; 13. Settling channel; 14. Base. Detailed Implementation

[0018] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0019] This invention relates to a centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances. The main structure includes a housing 1, with a collection tank 2 at the top. A hollow rotating shaft 3 is located inside the housing 1, with both ends penetrating the upper and lower ends of the housing 1 and rotatably connected to it. The bottom of the rotating shaft 3 is closed and connected to a drive motor 4 via a coupling. The top of the rotating shaft 3 is open and communicates with the collection tank 2, allowing the clarified liquid inside the rotating shaft 3 to drain into the collection tank 2. A filter membrane assembly 5 is located on the outer side of the inner portion of the rotating shaft 3 within the housing 1. The filter membrane assembly 5 includes multiple membrane sheets 10 sequentially sleeved on the rotating shaft 3 along its axial direction. The membrane sheets 10 are made of high-strength ceramic membranes or polyethersulfone. Made of (PES) organic membrane, the adjacent membranes 10 maintain an open spacing of 5mm-10mm, without being closed or obstructed. This ensures that the tea soup completely fills and washes the outer surface of each membrane 10 under the action of centrifugal force and shear force, maximizing the effective filtration area and preventing the formation of static "dead zones". Each membrane 10 has a guide cavity 11 inside, and multiple guide holes 6 are opened on the side wall of the rotating shaft 3. The multiple guide holes 6 are first arranged in a ring along the circumference of the rotating shaft 3, and then arranged in a ring along the axis. Each group of guide holes 6 corresponds to and is connected to a guide cavity 11, thereby forming a continuous clear liquid discharge channel of "guide cavity 11 - guide hole 6 - inner cavity of rotating shaft 3 - collection tank 2 - clear liquid outlet 7". The original tea soup in the shell 1, after being filtered through the membrane 10, can only enter the interior of the rotating shaft 3 through the guide hole 6. The bottom of one side of the collection tank 2 is provided with a clear liquid outlet 7 for discharging the separated and filtered tea soup clear liquid. The bottom of the shell 1 can be set as a cone structure, and the two sides are respectively provided with a feed inlet 8 and a concentrate outlet 9. The coarsely filtered original tea soup is pumped in through the feed inlet 8, and the retained tea soup concentrate is discharged through the concentrate outlet 9.

[0020] The outer edge of the filter membrane assembly 5 has an annular gap of 10mm-30mm between it and the inner wall of the housing 1, forming a sedimentation channel 13. This channel is the only channel through which the high-concentration retentate, i.e. the concentrate, settles downwards under the action of centrifugal force and gravity. While the clear tea liquor rises through the hollow part inside the rotating shaft 3 to the collection tank 2 for collection, the concentrated tea liquor settles in the sedimentation channel 13 and gathers in the cone area at the bottom of the housing 1, and is discharged through the concentrate outlet 9. This enables the invention to achieve a bidirectional stratified flow working mode, thereby simultaneously achieving tea liquor clarification and enrichment of macromolecular flavor substances in a single device.

[0021] Preferably, the top of the housing 1 is provided with a gas interface 12, through which an inert gas is connected. In this invention, nitrogen is selected. Before operation, a slightly positive pressure nitrogen is introduced to replace the air inside the housing 1, so that a slightly positive pressure inert atmosphere is maintained during the operation of the equipment, reducing the risk of oxidation of polyphenols in the tea soup. This invention, through the sealed housing 1 and the nitrogen protection system, avoids direct contact between the tea soup and the air under high temperature and high shear, thereby reducing the risk of oxidation and browning of polyphenols and helping to maintain the natural color and refreshing taste of the tea soup.

[0022] Preferably, the diaphragm 10 is circular, and the inner ring of the diaphragm 10 is fixed to the outside of the rotating shaft 3 by a sealing ring and a clamping nut. Since the inner ring of the diaphragm 10 is isolated from the tea soup space inside the housing 1 by the sealing ring, the tea soup on the outside can be prevented from directly entering the inner cavity of the rotating shaft 3, thus ensuring the filtration and separation effect of the tea soup.

[0023] Preferably, the bottom of the housing 1 is provided with a hollow base 14, and the drive motor 4 is disposed inside the base 14.

[0024] Preferably, the two ends of the rotating shaft 3 are dynamically sealed to the upper and lower ends of the housing 1 through a rotary sealing assembly, so that when the rotating shaft 3 rotates, the clear liquid inside the shaft can be reliably introduced into the collection tank 2 without leakage.

[0025] Example: A centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances includes a shell 1 with an upper round and lower conical shape. The shell 1 is made of food-grade stainless steel, and the bottom is a conical concentrated liquid collection hopper. A collection tank 2 is provided at the top of the shell 1, and a hollow base 14 is provided at the bottom of the shell 1. A hollow rotating shaft 3 is provided inside the shell 1. The two ends of the rotating shaft 3 pass through the upper and lower ends of the shell 1 respectively and are rotatably connected to the shell 1. The two ends of the rotating shaft 3 are dynamically sealed to the upper and lower ends of the shell 1 through a rotary sealing assembly. The bottom end of the rotating shaft 3 is closed. A drive motor 4 is connected via a coupling. The drive motor 4 is housed within the base 14 and is a variable frequency speed control motor. It is mounted on the base of the device and has a speed range of 500–2000 r / min, which can be flexibly adjusted according to the properties of the tea infusion and the membrane pore size. The top of the rotating shaft 3 is open and communicates with the collection tank 2. Multiple nano-ceramic membranes 10 are sequentially sleeved along the axial direction on the outer side of the inner part of the rotating shaft 3 within the housing 1. The inner ring of each membrane 10 is fixed to the outer side of the rotating shaft 3 by a sealing ring and a clamping nut. The pore size of the membrane 10 is 20 nm–100 nm. The pressure is 10kDa–100kDa, with an open gap of 5mm–10mm between adjacent membranes 10. Each membrane 10 has a flow guide cavity 11 inside. Multiple flow guide holes 6 are opened on the side wall of the rotating shaft 3. The multiple flow guide holes 6 are first arranged in a ring array along the circumference of the rotating shaft 3, and then arranged in an array along the axis. Each group of flow guide holes 6 corresponds to and is connected to a flow guide cavity 11. The clear liquid after the original tea soup in the shell 1 is filtered through the membranes 10 can only enter the interior of the rotating shaft 3 through the flow guide holes 6. An annular gap is left between the outer edge of the multiple membranes and the inner wall of the shell 1 to form a sedimentation channel 13. A clear liquid outlet 7 is provided at the bottom of one side of the collection tank 2. An inlet 8 and a concentrate outlet 9 are respectively provided on both sides of the bottom of the shell 1. A gas interface 12 is provided at the top of the shell 1. A nitrogen gas source is connected to the gas interface 12 to introduce nitrogen into the interior of the shell 1. During operation, a slight positive pressure of 0.02–0.05MPa is maintained.

[0026] During operation, close the bottom concentrate outlet 9 and the clear liquid outlet 7 of the collection tank 2; start the nitrogen protection system, introduce nitrogen from the gas interface 12 to replace the air in the housing 1 until the exhaust port (which can be set on the housing as needed, but will not be described here) is reached; slowly pump in tea soup through the feed port 8 so that the inside of the housing 1 and the area of ​​the filter membrane assembly 5 are filled with tea soup, forming an external pressure filtration area, maintaining an initial pressure of 0.2–0.6 MPa.

[0027] Start the drive motor 4, which drives the rotating shaft 3 and the filter membrane assembly 5 to rotate at high speed; Clear liquid path: During operation, an external feed pump continuously delivers coarsely filtered tea liquor into the housing 1 through the feed inlet 8, establishing and maintaining a working pressure inside the housing 1 higher than that at the clear liquid outlet 7. A back pressure valve or regulating valve is installed at the bottom concentrate outlet 9 to stabilize the pressure level inside the housing 1. Under the action of this working pressure and the pressure difference across the membrane, the tea liquor inside the housing 1 passes through the filter membrane from the outer surface of the membrane 10 and enters the guide cavity 11 inside the membrane 10. The filtrate (clear liquid) collects in the guide cavity 11, achieving solid-liquid separation from the raw tea liquor.

[0028] The inner ring of the diaphragm 10 is fixed to the outer wall of the rotating shaft 3 by a sealing ring and a clamping nut. The inner ring is isolated from the tea soup space inside the housing 1 by the sealing ring, allowing only the clear liquid that permeates through the membrane to enter the internal guide cavity 11 of the diaphragm 10. The internal guide cavity 11 of the diaphragm 10 is connected to the inner cavity of the rotating shaft 3 through the guide hole 6. The clear liquid that permeates through the membrane can only enter the interior of the rotating shaft 3 through the guide cavity 11 and the guide hole 6, and cannot bypass the membrane to enter the shaft directly.

[0029] The lower end of the rotating shaft 3 is a closed structure in the liquid circuit, serving only as a mechanical connector for transmitting torque and not connected to the external liquid circuit. Therefore, the clear liquid inside the shaft has no downward outlet. The upper end of the rotating shaft 3 is open and passes through the housing 1 to communicate with the inside of the liquid collection tank 2, allowing the clear liquid inside the rotating shaft 3 to be discharged into the liquid collection tank 2.

[0030] During operation, the external feed pump continuously delivers coarsely filtered tea soup into the housing 1 through the feed port 8, establishing and maintaining a working pressure higher than that at the clear liquid outlet 7 inside the housing 1. The clear liquid outlet 7 is usually connected to a near-normal pressure environment or a subsequent normal pressure pipeline. Therefore, an upward pressure difference is formed between the lower and upper parts of the inner cavity of the rotating shaft 3. Under the action of this pressure difference, the clear liquid entering the rotating shaft 3 flows from bottom to top along the inner cavity of the rotating shaft 3, enters the collection tank 2 through the upper opening of the rotating shaft 3, and is finally discharged continuously and stably from the collection tank 2 through the clear liquid outlet 7, resulting in clear and transparent tea soup.

[0031] Concentrate Pathway: Large molecules (such as water-soluble pectin, polysaccharides, high molecular weight glycoside complexes and fine tea residues) trapped by membrane 10 remain on the outside of membrane 10; Under the centrifugal force generated by high-speed rotation, these trapped components are thrown towards the inner wall area of ​​the shell 1 and accumulate in the annular settling channel 13 between the outer edge of the filter membrane assembly 5 and the inner wall of the shell 1. As the concentration and apparent density increase, the concentrate flows slowly downward along the inner wall of the shell 1 in the settling channel 13 under the action of gravity, and settles into the conical concentration hopper at the bottom of the shell 1. By adjusting the valve opening of the bottom concentrate outlet 9, concentrated tea slurry of different concentrations can be discharged continuously or intermittently, achieving online enrichment of macromolecular flavor substances (rich matrix).

[0032] Numerical prediction explanation and simulation verification The operating parameters (such as gap width, pressure, and rotational speed) and performance indicators (such as flux and retention rate) mentioned in this specification and examples are predicted values ​​calculated based on fluid dynamics (CFD) models and mass transfer dynamics. These values ​​are intended to illustrate the expected technical performance of this device under typical design conditions.

[0033] 1. Simulation optimization of device operating parameters Based on shear force field simulation, the present invention determines the following preferred parameter ranges: Settling channel width (10–30 mm): Simulations show that when the width is within this range, macromolecular substances experience the strongest centrifugal settling effect and are less prone to wall turbulence interference.

[0034] Rotation speed (500~2000 r / min): This speed range is predicted to generate sufficient shear force on the membrane surface to remove the filter cake layer and prevent membrane pore blockage.

[0035] 2. Performance simulation comparison To verify the technical advantages of the present invention, simulation software was used to compare the performance prediction of the device of the present invention (example) with that of a traditional plate and frame filter device (comparative example).

[0036] Table 1. Predicted data on the stability of tea infusion clarification flux

[0037] Note: The example setting is a rotation speed of 1500 r / min and a slight positive pressure of 0.03 MPa; the data are typical values ​​predicted by the model.

[0038] Table 2. Predicted data on retention rates of key flavor compounds

[0039] in conclusion: Simulation results show that the device of the present invention, through a specific centrifugal shear structure and sedimentation channel design, is predicted to effectively solve the problems of rapid flux decay and easy oxidation and discoloration in traditional filtration, and significantly improve the enrichment efficiency of macromolecular flavor substances.

Claims

1. A centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances, characterized in that: The device includes a sealed housing (1), a liquid collection tank (2) at the top of the housing (1), and a hollow rotating shaft (3) inside the housing (1). The two ends of the rotating shaft (3) pass through the upper and lower ends of the housing (1) respectively, and a rotating sealing assembly is provided between the rotating shaft (3) and the housing (1) to achieve dynamic sealing. The bottom end of the rotating shaft (3) is closed and connected to a drive motor (4), and the top end of the rotating shaft (3) is open and extends into the liquid collection tank (2) to communicate with it. A filter membrane assembly (5) is sleeved on the outer side of the part of the rotating shaft (3) inside the housing (1). Multiple guide holes (6) are opened on the side wall of the rotating shaft (3). The original tea soup in the housing (1) can only enter the rotating shaft (3) through the guide holes (6) after being filtered by the filter membrane assembly (5). A radial width of 10 to 30 mm is left between the outer edge of the filter membrane assembly (5) and the inner wall of the housing (1). A ring gap of mm forms a macromolecular sedimentation channel (13); the bottom of one side of the collection tank (2) is provided with a clear liquid outlet (7), and the bottom of the shell (1) is provided with a feed inlet (8) and a concentrate outlet (9) on both sides respectively.

2. The centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances according to claim 1, characterized in that: The filter membrane assembly (5) includes a plurality of circular membranes (10) sequentially sleeved on the rotating shaft (3) along the axial direction. The inner ring of the membrane (10) is fixed to the outside of the rotating shaft (3) by a sealing ring and a clamping nut. Each membrane (10) has a flow guiding cavity (11) inside. A plurality of flow guiding holes (6) correspond to and communicate with a plurality of flow guiding cavities (11). A gap of 5 to 10 mm is left between adjacent membranes (10).

3. The centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances according to claim 1, characterized in that: The top of the housing (1) is provided with a gas interface (12), through which an inert gas source is connected to maintain a slightly positive pressure inert atmosphere of 0.02 to 0.05 MPa inside the housing (1) during device operation.

4. The centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances according to claim 1, characterized in that: The drive motor (4) is a variable frequency speed control motor, used to drive the rotating shaft (3) and the filter membrane assembly (5) to rotate at a speed of 500 to 2000 r / min.

5. The centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances according to claim 1, characterized in that: The bottom of the shell (1) is provided with a conical concentration hopper, and the concentrate outlet (9) is located at the bottom of the conical concentration hopper.

6. The centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances according to claim 1, characterized in that: The bottom of the housing (1) is provided with a hollow base (14), the drive motor (4) is set inside the base (14), and the rotating shaft (3) is connected to the drive motor (4) through a coupling.

7. The centrifugal membrane coupling device for clarifying tea infusion and enriching macromolecular flavor substances according to claim 1, characterized in that: Start the drive motor (4) to make the filter membrane assembly (5) rotate and generate shear force; control the pressure inside the housing (1) to be slightly positive, so that the clear tea liquid passes through the membrane and enters the rotating shaft (3) to be discharged upward, while the macromolecular flavor substances are enriched by descending along the sedimentation channel (13) under the action of centrifugal force.

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