Ascites filter and ascites protein extraction system and method comprising the ascites filter

Abstract

The present invention relates to a kind of ascites filter and ascites protein extraction system and method comprising the ascites filter of the present invention, the proportion of polysulfone resin material in the hollow fiber membrane silk material used in the ascites filter is 55-65%, the membrane pore size of the hollow fiber membrane silk is ≤0.285μm and the membrane pore size is 0.25μm or more and the membrane pore accounts for ≥30% of the total membrane pore area, and preferably the membrane pore size is 0.20μm or more and the membrane pore accounts for 40-65% of the total membrane pore area. Thereby, the ascites filter can solve the technical problems that the protein (mainly composed of albumin and globulin) recovery rate in the existing ascites is low and the filter pore of the membrane silk is prone to obvious deformation or damage under backwash pressure to a certain extent, further reduce the permeability of harmful components when improving the ascites protein recovery rate, and improve the reliability and safety of intravenous reinjection of ascites reclaimed material.

Description

Technical Field

[0001] The present invention relates to the technical field of ascites filtration, and in particular to an ascites filter and an ascites protein extraction system and method comprising the ascites filter. Background Art

[0002] In recent years, cell-free and concentrated ascites reinfusion therapy (Cell-free and Concentrated Ascites Reinfusion Therapy) has been used to treat patients with cirrhosis and cancer. The process generally involves extracting ascites from the patient's peritoneal cavity, filtering it to remove cellular components such as cancer cells and bacteria from the protein solution. After initial purification, the ascites is further processed using a concentration technique to remove excess water while retaining valuable components such as proteins and other macromolecules. This process significantly reduces the fluid volume while preserving the important protein content. Finally, the filtered and concentrated fluid is reinjected into the patient's circulatory system. This procedure helps replenish lost protein, maintain blood volume, and alleviate symptoms such as shortness of breath and loss of appetite caused by excessive ascites.

[0003] During the filtration process of this therapy, the pores of the hollow fiber membrane are blocked by substances from cancer cells and bacteria. Under the filtration operation pressure and flushing pressure, it is easy to cause cancer cells, bacteria, etc. to break or the pores of the membrane to be damaged. A large amount of harmful components pass through the filter membrane into the concentrated liquid, and the effect of filtering out the pathogenic substances cannot be achieved. In this case, when the concentrated liquid is reinjected intravenously, the patient will have side effects such as high fever, which will consume the patient's physical strength and energy.

[0004] Existing technologies such as JP2023154449A, JP2023001798A, CN106794287B, CN106999855A, and DE2611212C2 disclose similar filters. However, these filters still have some common shortcomings. The membrane filaments used in these filters have too small a pore size, with a maximum of no more than 0.2 μm. The recovery rate of proteins and immune proteins is difficult to exceed 85%. This pore size is not only prone to clogging, but also inevitably leads to increased flushing frequency, which subjects the membrane filaments to more frequent impacts. For example, the protein transmittance of CN106794287B is only 80%. Although some technical solutions, such as CN106999855A, mention a pore size of 0.010 μm-10 μm, preferably 0.05 μm-5 μm, such a wide pore size distribution makes the membrane filaments unsuitable for ascites filtration, which can easily lead to the recovery of harmful substances and pose a safety hazard to patients during intravenous reinfusion. Summary of the Invention

[0005] (1) Technical issues to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an ascites filter and an ascites protein extraction system and method comprising the ascites filter, which can, to a certain extent, solve the technical problems of low protein recovery rate in the existing ascites and the pores of the membrane filaments being easily deformed or damaged under backwash pressure, and further reduce the permeability of harmful components while improving the ascites protein recovery rate.

[0007] (2) Technical solution

[0008] In a first aspect, the present invention provides an ascites filter, comprising: a filter cavity, wherein a plurality of hollow fiber membranes are installed in the filter cavity, wherein the hollow fiber membranes are spaced apart, and sealing materials are provided at both ends of the hollow fiber membranes, wherein the sealing materials seal the spacing between the hollow fiber membranes and the spacing between the hollow fiber membranes and the inner wall of the filter cavity;

[0009] The filter cavity includes a first end and a second end, the first end is provided with a flushing liquid inlet, and the second end is provided with a filtrate outlet; the two ends of the hollow fiber membrane filament form a distance with the first end and the second end respectively, the distance between the hollow fiber membrane filament and the first end of the filter cavity constitutes a flushing liquid inlet buffer zone, and the distance between the hollow fiber membrane filament and the second end of the filter cavity constitutes a filtrate outlet buffer zone; an ascites inlet is provided on one side of the filter cavity, the ascites inlet is communicated with the filter cavity and corresponds to between the two ends of the hollow fiber membrane filament, and the ascites inlet is far away from one end of the filtrate outlet; a flushing liquid outlet is also provided on one side of the filter cavity, the flushing liquid outlet is communicated with the filter cavity and corresponds to between the two ends of the hollow fiber membrane filament, and the flushing liquid outlet is arranged at an end far away from the flushing liquid inlet;

[0010] In which, the hollow fiber membrane comprises a mixture of a first polymer material and a second polymer material, the first polymer material is a polysulfone resin, and the second polymer material is at least one selected from polyethylene, polypropylene, polyvinyl alcohol and polyacrylonitrile; the mass proportion of the polysulfone resin is 55-65%; the membrane pore size of the hollow fiber membrane is d, d≤0.285μm, and the membrane pores with a membrane pore size of more than 0.25μm account for ≥30% of the total membrane pore area.

[0011] According to a preferred embodiment of the present invention, the mass proportion of the polysulfone resin in the hollow fiber membrane is 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64% or 65%; and the membrane pores with a pore size of 0.25 μm or more account for no more than 50% of the total membrane pore area, that is, the membrane pores with a pore size of 0.25 μm or more account for 30-50% of the total membrane pore area; further preferably, the membrane pores with a pore size of 0.20 μm or more account for 40-65% of the total membrane pore area. If the proportion of membrane pores with a pore size of 0.20 μm or more is too high, it will affect the mechanical strength and deformation resistance of the hollow fiber membrane, resulting in a decrease in its ability to withstand filtration and flushing pressure; therefore, preferably, the membrane pores with a pore size of 0.25 μm or more account for no more than 50% of the total membrane pore area, and the membrane pores with a pore size of 0.20 μm or more account for 40-65% of the total membrane pore area.

[0012] Polysulfone resins enhance the compressive strength and toughness of hollow fiber membranes. However, while polysulfone (PSU) resins possess excellent mechanical strength and chemical stability, they are highly hydrophobic and difficult to modify to hydrophilic properties. This high hydrophobicity can lead to high protein adsorption and cell adhesion, thus impacting filtration efficiency and membrane life. Furthermore, hollow fiber membranes made entirely of polysulfone resins exhibit poor processability, making it difficult to achieve the desired pore size distribution.

[0013] Preferably, the hollow fiber membrane comprises a first polymer material and a second polymer material, wherein the first polymer material is a polysulfone resin, which accounts for 55-65% by weight of the hollow fiber membrane; the remainder is a second polymer material, and the second polymer material is at least one of polyethylene, polypropylene, polyvinyl alcohol, and polyacrylonitrile doped with 3-8wt% PVP. Polyvinylpyrrolidone (PVP) has good biocompatibility and hydrophilicity, increasing the hydrophilicity of the hollow fiber membrane, reducing the chance of cell adhesion to the membrane surface, thereby reducing cell permeability, reducing nonspecific binding and adsorption of proteins to the membrane, and improving protein recovery.

[0014] Preferably, the surface of the hollow fiber membrane is further subjected to a hydrophilic treatment. The methods of hydrophilic treatment include but are not limited to plasma, chemical grafting or hydrophilic coating, etc. Among them, plasma treatment generally uses low-pressure plasma or atmospheric pressure plasma technology. This treatment can introduce polar groups (such as hydroxyl groups, carboxyl groups) on the membrane surface, thereby increasing the hydrophilicity of the membrane surface. Commonly used plasma treatment gases include oxygen, argon, nitrogen, carbon dioxide, etc. Different gases produce different active particles, and the effects on membrane surface modification are also different. The processing power can be set to 50W-300W, and the processing time is from a few seconds to a few minutes, usually operating in the range of tens of Pascals to hundreds of Pascals. Chemical grafting can use acrylic monomers (such as acrylic acid, methacrylic acid) or PEG grafting. The hydrophilic coating can use natural polysaccharides such as chitosan, etc., and the natural polysaccharide solution is applied to the membrane surface by dip coating, and then solidified by heating or cross-linking agent to form a stable hydrophilic layer. These measures can reduce the adsorption of proteins and contamination of other biological components by the hollow fiber membrane.

[0015] Preferably, the membrane pore size is d≤0.285μm, and the proportion of membrane pores with a pore size of 0.25μm or larger is 30-50%, allowing some proteins and immune proteins to pass through the filtration pores and be recovered. This is beneficial for both improving protein recovery rate and the compressive strength of the hollow fiber membrane. Membrane pores with a pore size of 0.25μm or larger are relatively large pores, which can improve the recovery rate of ascites protein. However, if their proportion is too large, the compressive strength and toughness of the hollow fiber membrane may deteriorate. During ascites filtration, the pore size of the hollow fiber membrane further increases under the operating pressure, and even ruptures (merged pores) may occur, causing harmful substances to penetrate into the protein recovery liquid, which is unsafe.

[0016] According to a preferred embodiment of the present invention, the diameter of the flushing liquid outlet is D1, the flushing liquid inlet is D2, and D1 / D2 is 1.8-2.2, preferably, D1 / D2 is 2. By increasing the diameter of the flushing liquid outlet to approximately twice the diameter of the flushing liquid inlet, this facilitates backwashing of the filter, increases the pressure differential between the inside and outside of the hollow fiber membrane at a lower operating pressure, and produces a better flushing effect with minimal pressure, improving flushing efficiency and saving time. As previously mentioned, if pore deformation, pore breakage, or pore merging occurs, the safety of the ascites recovered material is reduced.

[0017] According to a preferred embodiment of the present invention, the filling rate of the hollow fiber membrane in the filter cavity is 30-40%, more preferably 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, or 40%, calculated as the ratio of the total cross-section of the hollow fiber membrane to the cross-section of the filter cavity. The filling rate of the hollow fiber membrane in the filter cavity determines the membrane filtration area under a certain filter cavity length.

[0018] According to a preferred embodiment of the present invention, the filter cavity is a cylindrical filter cavity with an inner diameter D3 of 4-4.5 cm. The total specific surface area of ​​the hollow fiber membrane filaments within the filter cavity is 1.3-2.0 m2. When the filling rate of the hollow fiber membrane filaments in the filter cavity is 30-40%, the ratio of the rinsing liquid outlet D1 / D3 is 1 / 2-1 / 3. The total specific surface area of ​​the hollow fiber membrane filaments within the filter cavity is the membrane filtration area of ​​the ascites filter. When the inner diameter of the filter cavity is small, the membrane filtration area can be met by increasing the length of the hollow fiber membrane filaments within the filter cavity. However, if the hollow fiber membrane filaments are too long, packaging becomes more difficult, and the midsection of the hollow fiber membrane filaments becomes fragile and may break. When the inner diameter of the filter cavity is large, the length of the hollow fiber membrane filaments must be shortened to meet the membrane filtration area. In this case, the filtration path becomes shorter and prone to clogging.

[0019] According to a preferred embodiment of the present invention, in the filter chamber, the hollow fiber membrane is installed in an S-shape or a C-shape, so that the hollow fiber membrane has a certain curvature. In the filter chamber, the distance between the two ends of the hollow fiber membrane is L1 (installation length), the actual length of the hollow fiber membrane is L2, and L2 / L1 is 1.05-1.3, preferably 1.1-1.2. Experiments have shown that when the membrane has a certain curvature, under the conditions of filtration and backwashing, the filtrate or backwash water always acts on the surface of the membrane at a certain non-vertical angle, which not only improves the filtration efficiency, but also reduces the damage to the membrane caused by the filtration operation pressure and the backwashing pressure.

[0020] According to a preferred embodiment of the present invention, the sealing material is a waterproof sealing adhesive, which is bonded to the outer surface of the end of the hollow fiber membrane and is used to seal the gaps between the hollow fiber membranes.

[0021] In a second aspect, the present invention provides an ascites protein extraction system comprising the ascites filter, which includes the above-mentioned ascites filter and concentrator, the filter and concentrator are both arranged or installed horizontally, the filtrate outlet of the ascites filter and the raw liquid inlet of the concentrator are connected by a pipeline, the concentrated liquid outlet of the concentrator is connected to a pump, and the concentrated liquid is introduced into a concentrated liquid collection device through the pump, a waste liquid outlet is also provided on one side of the concentrator, and the waste liquid outlet is connected to a negative pressure suction device; no pressurizing device is provided at the front end of the ascites filter.

[0022] Preferably, the concentrator is a hollow fiber membrane device, which includes a shell and a hollow fiber membrane bundle arranged inside the shell, one end of the shell is a raw liquid inlet, which is connected to the filtrate outlet of the ascites filter, and the other end of the shell is a concentrated liquid outlet, which is connected to the pump; the waste liquid outlet is set on one side of the shell, the outer end of the waste liquid outlet is connected to the negative pressure suction device, and the inner end of the waste liquid outlet is connected to the interior of the shell but not to the hollow channel of the hollow fiber membrane bundle.

[0023] In a third aspect, the present invention provides a method for extracting ascites protein, which is implemented by the ascites protein extraction system described in the above scheme, and comprises the following steps:

[0024] S1. Place the ascites filter and concentrator horizontally on the operating platform;

[0025] S2. Place the bag of normal saline at a height of 30-50 cm on the operating platform, allowing the normal saline to enter the filter cavity from the ascites inlet of the filter under gravity and exit from the rinsing liquid outlet, thereby completing the flushing of the interior of the filter cavity and the exterior of the hollow fiber membranes; then, close the rinsing liquid outlet, open the valve and negative pressure suction device between the ascites filter and the concentrator, allowing the normal saline to enter the ascites inlet of the filter under gravity and exit from the filtrate outlet, thereby completing the flushing of the interior of the hollow fiber membranes of the ascites filter;

[0026] S3, the ascites bag is placed at a height of 30-50cm on the operating platform, the valves of the ascites bag and the ascites filter are opened, and the negative pressure suction device and the pump connected to the concentrator are opened at the same time; the working pressure of the negative pressure suction device is adjusted, and the pump speed is adjusted to 10-30mL / min so that the filtration pressure of the filter is 30KPa (225mmHg)-60KPa (450mmHg); at this time, the ascites enters the filter cavity from the ascites inlet of the filter under gravity, and the protein-containing filtrate is discharged from the filtrate outlet and enters the concentrator. After entering the concentrator, it flows in the hollow channel of the hollow fiber membrane bundle of the concentrator, and excess water and electrolytes are filtered to the outside of the hollow fiber membrane bundle and discharged from the waste liquid outlet under the operation of the negative pressure suction device; the protein-containing concentrated solution remains inside the hollow fiber membrane bundle and, driven by the pump, enters the concentrated solution collecting device;

[0027] S4. When the outlet velocity of the concentrated liquid drops to 50% of the initial velocity, backwashing is performed. The backwashing process is as follows:

[0028] S41. Close the valve between the ascites bag and the ascites inlet of the filter to keep the filter connected to the concentrator; inject normal saline (preferably 100 mL, manually pushed in with a syringe) into the flushing fluid inlet, and use the normal saline to push the protein-containing liquid inside the hollow fiber membrane of the ascites filter into the concentrator for continued concentration processing;

[0029] After S42 and the treatment are completed, the pump and the negative pressure suction device are turned off, the valve between the filter and the concentrator is closed, the valve between the ascites bag and the ascites inlet of the filter is opened, and normal saline (preferably 200 mL, manually pushed in using a syringe) is injected into the flushing fluid inlet, and the ascites that has entered the filter cavity is pushed back into the ascites bag by the normal saline;

[0030] S43. Close the valve between the ascites bag and the ascites inlet of the filter, open the rinsing fluid outlet, and inject normal saline (preferably 50 mL, manually pushed in using a syringe) into the rinsing fluid inlet. The normal saline will penetrate from the inside of the hollow fiber membrane of the filter to the outside and flush out the blockage outside the hollow fiber membrane. Repeat the injection of normal saline 8-12 times. The pressure of the injected normal saline should not exceed 66.6 kPa (500 mmHg).

[0031] S5. After the flushing is completed, close the flushing fluid outlet and flushing fluid inlet, open the valve between the ascites bag and the filter, open the valve between the ascites filter and the concentrator, turn on the pump and negative pressure suction device connected to the concentrator, and continue to extract ascites protein according to the method of S3.

[0032] (3) Beneficial effects

[0033] The technical effects of the present invention include but are not limited to the following:

[0034] 1. By more rationally designing the pores of the hollow fiber membrane of the filter, the pore size of the hollow fiber membrane is ≤0.285μm, and the pores with a pore size of 0.25μm or more account for ≥30% of the total pore area. This greatly improves the recovery rate of ascites protein, allowing the ascites protein recovery rate to exceed 90%, retaining more important protein components in the patient and reducing the physical and mental consumption of ascites dialysis on the patient. This protein recovery rate is higher than the current highest ascites protein recovery rate of the existing technology, which does not exceed 85%.

[0035] 2. When the pore size of the hollow fiber membrane increases, the mechanical strength and resistance to filtration operation pressure and flushing pressure of the membrane may be weakened. A certain proportion of polysulfone materials is mixed into the material of the hollow fiber membrane to make the mixing amount reach 55-65%. The higher polysulfone resin content enhances the compressive strength and toughness of the membrane and enhances the mechanical strength.

[0036] 3. Existing technologies for improving ascites filters involve many aspects, including various optimization designs for the number of filter membrane filaments, central pore diameter, membrane filament outer diameter, membrane filament arrangement density in the filter cavity, membrane filament curvature, and filtration operating pressure. However, none of these methods effectively address the impact and damage to the membrane filaments caused by backwashing, which can easily cause significant deformation or damage to the pore size of the filament membrane, thereby reducing the quality of ascites filtration. The present invention, by enlarging the diameter of the flushing liquid outlet of the ascites filter to 1.8-2.2 times (preferably 2 times) the diameter of the flushing liquid inlet, can produce a better flushing effect with extremely low flushing pressure, thereby improving flushing efficiency. This helps reduce the impact of flushing pressure on the hollow fiber membrane filaments, protects the stability of the membrane pore size, and maintains the accuracy and stability of the membrane filament's retention parameters over a long period of time.

[0037] 4. The ascites protein extraction system of the present invention does not have any pressurizing device at the front end of the filter, which avoids the damage of cancer cells, bacteria, red blood cells and other organisms due to excessive pressurization (failure to achieve the filtering effect) into fragments that cannot be retained by the filter. While ensuring the ascites protein extraction rate, it also reduces the residual harmful substances, improves the reinfusion safety of the ascites recovered concentrated protein liquid, and reduces the side effects of reinfusion.

[0038] 5. During the ascites protein extraction process, the ascites filter and concentrator are placed horizontally on the operating platform. This allows the ascites filtration process to rely primarily on gravity flow into the filter. The ascites flows naturally horizontally within the filter. This prevents the vertically placed filter from experiencing severe deformation at the bottom of the membrane due to greater pressure and less deformation at the top of the membrane filaments after a period of operation. Severely deformed membrane filaments and membrane pores lose their ability to retain harmful components. Furthermore, inconsistent retention parameters at both ends of the membrane filaments can easily cause some heavier harmful substances to pass through the filter from the bottom of the membrane filaments.

[0039] 6. The filtration pressure of the ascites protein extraction system is mainly regulated by the rear negative pressure suction device connected to the concentrator, so that the filtration pressure of the ascites filter is 225-450 mmHg, preventing the problem of damage to organisms such as cancer cells, bacteria, and red blood cells caused by pre-pressurization of the filter, and effectively protecting the hollow fiber membrane of the ascites filter.

[0040] 7. During the ascites protein extraction process, the flushing fluid inlet is flushed by manually injecting physiological saline with a syringe, which is in line with the traditional automated pressurized flushing equipment. The manual syringe push-in flushing can reduce the damage rate of organisms such as cancer cells, bacteria, and red blood cells, and the membrane pore damage rate, greatly reducing the chance of harmful components entering the filtrate and reducing the risk of side effects of the protein concentrate being transfused back to the patient. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the structure of the ascites filter of the present invention.

[0042] Figure 2 Schematic diagram of the ascites protein extraction system of the present invention. DETAILED DESCRIPTION

[0043] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0044] like Figure 1The figure shows a schematic diagram of an ascites filter according to the present invention. The ascites filter 100 includes a cylindrical filter chamber 2, within which a plurality of hollow fiber membranes 11 are installed. These hollow fiber membranes 11 maintain a certain distance 5 between each other (the hollow fiber membranes are not in close contact), and sealing materials 4 are provided at both ends of the hollow fiber membranes. These sealing materials 4 seal the distance between the hollow fiber membranes 11 and the distance between the hollow fiber membranes 11 and the inner wall of the filter chamber 2. The filter chamber 2 can be made of a medical-grade polymer resin, preferably a transparent polymer resin. The sealing material 4 is a waterproof sealing adhesive that is bonded to the outer surface of the end of the hollow fiber membrane 11 to close the distance between the hollow fiber membranes 11 and form a watertight sealing surface at both ends of the hollow fiber membrane 11. The filter chamber 2 includes a first end and a second end, each of which is provided with a top cover 1. The top cover 1 at the first end is provided with an inlet 9 for flushing liquid, and the top cover at the second end is provided with an outlet 8 for filtrate. The two ends of the hollow fiber membrane 11 form a distance with the top cover 1 at the first end and the top cover 1 at the second end, respectively. The distance between the hollow fiber membrane 11 and the first end of the filter chamber 2 constitutes a flushing liquid inlet buffer zone A, which is located between the sealing surface of the end of the hollow fiber membrane 11 and the top cover 1 at the first end. The distance between the hollow fiber membrane 11 and the second end of the filter chamber 2 constitutes a filtrate outlet buffer zone B, which is located between the sealing surface of the end of the hollow fiber membrane 11 and the top cover 1 at the second end. The flushing liquid inlet buffer zone A is preferably 1 / 20-1 / 30 of the volume of the entire filter chamber 2, and the filtrate outlet buffer zone B is preferably 1 / 20-1 / 30 of the volume of the entire filter chamber 2. The volume ratio of the flushing liquid inlet buffer zone A and the filtrate outlet buffer zone B can maintain an appropriate filtration pressure difference or flushing pressure difference inside the hollow fiber membrane 11 in the filter chamber 2, improve the space utilization of the filter chamber 2, save the injection amount of flushing liquid, and improve the recovery rate of ascites components. The flushing liquid inlet buffer zone A and the filtrate outlet buffer zone B are both in communication with the internal channel 3 of the hollow fiber membrane 11 .

[0045] An ascites inlet 7 is provided on one side of the filter chamber 2. The ascites inlet 7 is connected to the interior of the filter chamber 2 and corresponds to the space between the two ends of the hollow fiber membrane filaments 11. The ascites inlet 7 is not directly connected to the hollow channel of the hollow fiber membrane filaments 11. The ascites inlet 7 is provided at an end away from the filtrate outlet 8. A flushing liquid outlet 10 is also provided on one side of the filter chamber 2. The flushing liquid outlet 10 is connected to the interior of the filter chamber 2 and corresponds to the space between the two ends of the hollow fiber membrane filaments 11. The flushing liquid outlet 10 is not directly connected to the hollow channel of the hollow fiber membrane filaments 11. The flushing liquid outlet 10 is provided at an end away from the flushing liquid inlet 9. At present, the diameters of the flushing liquid inlet and the flushing liquid outlet of the hollow fiber membrane are basically equal. In the angle embodiment of the present invention, the diameter D1 of the flushing liquid outlet 10 is 1.8-2.2 times the diameter D2 of the flushing liquid inlet 9 (D1 / D2=1.8-2.2), preferably 2 times. According to the Bernoulli equation, when the amount of flushing fluid is the same, by setting the flushing fluid outlet 10 to twice the flushing fluid inlet diameter, a larger pressure differential can be generated inside and outside the hollow fiber membrane filaments 11. This facilitates achieving a better flushing effect with less flushing fluid, improving backwashing efficiency, saving backwashing time, and reducing mechanical damage to the hollow fiber membrane filaments 11 caused by backwashing. The flushing fluid can enter the flushing fluid inlet buffer A through the flushing fluid inlet buffer A. After being distributed through the flushing fluid inlet buffer A, it enters the internal channel 3 of the hollow fiber membrane filaments 11. The internal channel 3 of the hollow fiber membrane filaments 11 is then used to flush contaminants or blockages adhering to the outer wall of the hollow fiber membrane filaments 11. The ascites sample enters the filtration cavity 2 through the ascites inlet 7 and is distributed in the spacing 5 between the hollow fiber membrane filaments 11. Proteins, water, etc. pass through the filter pores and enter the internal channel 3. After exiting the internal channel 3, they are collected in the filtrate outlet buffer B and then discharged through the filtrate outlet 8.

[0046] The hollow fiber membrane 11 comprises a mixture of a first polymer material and a second polymer material, and is manufactured by a process of casting a membrane using a casting solution and phase transfer. The first polymer material is a polysulfone resin, which accounts for 55-65% of the mass of the hollow fiber membrane 11. A high content of polysulfone resin can increase the mechanical strength and toughness of the hollow fiber membrane 11. The second polymer material is at least one selected from polyethylene, polypropylene, polyvinyl alcohol, and polyacrylonitrile, and 3-8 wt% PVP is incorporated therein. The hollow fiber membrane 11 has a membrane pore size d, d≤0.285 μm. The membrane pores with a membrane pore size of 0.25 μm or greater account for more than 30-50% of the total membrane pore area, and more preferably, the membrane pores with a membrane pore size of 0.20 μm or greater account for 40-65% of the total membrane pore area. For example, the membrane pores with a membrane pore size of 0.25 μm or greater account for 30% of the total membrane pore area, while the membrane pores with a membrane pore size of 0.20 μm or greater account for 40%, 50%, or 60% of the total membrane pore area. The hollow fiber membrane 11 that meets this condition can stably achieve an ascites protein recovery rate of more than 90% under an operating pressure of 500 mmHg or higher, and can well take into account the mechanical strength and compressive strength of the hollow fiber membrane, which is conducive to maintaining the stability of the hollow fiber membrane pore size, shape and retention parameters, and improving the reliability of ascites protein recovery.

[0047] Ascites may contain cancer cells and various bacteria, including bacteria with diameters of 0.3-3 μm, staphylococci with diameters of 1 μm, red blood cells with diameters of 2-3 μm, platelets with diameters of 2-3 μm, Escherichia coli with diameters of 1-2 μm, yeast with diameters of 5 μm, white blood cells with diameters of 6-30 μm, and cancer cells with diameters of 10 μm. Therefore, setting the pore size of the hollow fiber membrane 11 to below 0.285 μm can filter out almost all useless or harmful components in ascites, improve dialysis efficiency, reduce the frequency of fiber membrane blockage, and increase the recovery rate of ascites protein.

[0048] Among them, the mass proportion of polysulfone resin in the hollow fiber membrane 11 is 55%, 56%, 57%, 58%, 59%, 60%, 62% or 65%. Although, in theory, the higher the proportion of membrane pores with a pore size of 0.25μm-0.285μm, the higher the protein recovery rate in ascites, once the proportion of membrane pores with a pore size of more than 0.25μm is too high, the mechanical strength and deformation resistance of the hollow fiber membrane 11 are weakened, resulting in a decrease in its ability to resist filtration and flushing pressure. Therefore, the membrane pores with a pore size of more than 0.25μm in the filter membrane of the hollow fiber membrane 11 account for no more than 50% of the total membrane pore area.

[0049] Since polysulfone is a hydrophobic material, if its proportion is too high, the hydrophobicity of the hollow fiber membrane filament 11 will be too strong. In order to further improve the hydrophilicity of the hollow fiber membrane filament 11, the hollow fiber membrane filament 11 can be treated with plasma, chemical grafting or hydrophilic coating after the preparation is completed, so as to introduce polar groups on the surface of the hollow fiber membrane filament 11, thereby improving its hydrophilicity. The improved hydrophilicity is beneficial to protein filtration and reducing the fouling of the hollow fiber membrane filament by cancer cells. The hydrophilic membrane surface has a high hydration capacity and good wettability, which can reduce the non-specific adsorption of proteins on its surface, and is more conducive to improving the recovery rate and filtration efficiency of proteins. Treatments such as plasma, chemical grafting or hydrophilic coating are common treatments to improve the hydrophilicity of the hollow fiber membrane filament 11.

[0050] The filling rate of the hollow fiber membrane filaments 11 in the filter chamber 2 is 30-40%. The filling rate is calculated based on the ratio of the total cross-section of all the hollow fiber membrane filaments 11 in the filter chamber 2 to the internal cross-section of the filter chamber 2. The filter chamber 2 is a cylindrical filter chamber. If the inner diameter of the filter chamber 2 is defined as D3 and the flushing liquid outlet is D1, when the filling rate of the hollow fiber membrane filaments in the filter chamber is 30-40%, D1 / D3 is 1 / 2-1 / 3. In a filter 100 of a preferred embodiment, the total specific surface area of ​​the hollow fiber membrane filaments 11 in the filter chamber 2 is 1.3-2.0㎡. The total specific surface area is actually the membrane filtration area of ​​the filter 100. Among them, the filling rate of the hollow fiber membrane filaments 11 in the filter chamber 2 can be 31%, 33%, 35%, 36%, 37%, 38% or 40%. Typically, the length of the filter chamber 2 is set to 40-60 cm, the inner diameter D3 is 4-4.5 cm, and the flushing liquid outlet D1 can be set to 1.5-2.25 cm. The ratio of the flushing liquid outlet D1 to the inner diameter D3 of the filter chamber 2 takes into account the strength of the filter chamber 2 structure (if D1 accounts for too large a proportion, the filter chamber 2 becomes fragile; the smaller the proportion of D1, the greater the pressure inside the filter chamber 2) and the appropriate filtration pressure and flushing pressure of the filter chamber 2. The larger the membrane filtration area, the faster the filtration speed, but when the volume of the filter chamber is determined, it means that the filling rate of the hollow fiber membrane filaments 11 is greater, the distance between the membrane filaments is reduced, more physiological saline is required for backwashing, and a larger operating pressure is required for filtration, which is not conducive to the stability of the membrane filament pore structure and the retention parameters; and increasing the volume of the filter chamber is prone to protein loss in ascites.

[0051] like Figure 1As shown, in the filter chamber 2, the hollow fiber membrane 11 is not installed straight, but is installed in the filter chamber 2 in an S-shape or C-shape, so that the hollow fiber membrane 11 has a certain curvature. Under backwashing or filtration pressure, the hollow fiber membrane 11 presents a certain S-shaped swinging state. Specifically, assuming that the distance between the two ends of the hollow fiber membrane 11 is L1 (i.e., the length of the interval located inside the filter chamber 2), and the actual length of the hollow fiber membrane is L2, then L2 / L1 is 1.05-1.3, preferably 1.1-1.2. Experiments have shown that when the hollow fiber membrane 11 has a certain curvature, under filtration and backwashing conditions, the substance molecules and water molecules in the filtrate or backwash water always act on the membrane surface at a certain non-vertical angle, which not only improves the filtration efficiency, but also reduces the mechanical damage of the filtration operation pressure and backwashing pressure to the hollow fiber membrane 11.

[0052] The casting solution for preparing the hollow fiber membrane filaments 11 is composed of: 20-22.5% of a second polymer material, 27.5-37.2% of a polysulfone resin, 2-10% of a pore-forming agent, and the remainder being a solvent; the second polymer material is at least one selected from polyethylene, polypropylene, polyvinyl alcohol, and polyacrylonitrile, and 3-8wt% of PVP is added. The casting solution for the hollow fiber membrane filaments is first prepared, filtered, and degassed, and then extruded from a spinneret consisting of two concentric tubes. After a 20-80cm dry spinning process, the casting solution is coagulated in an aqueous solution having a solvent content of 40-50% by mass and a temperature of 5°C-40°C to obtain a spun yarn. The spun yarn is then subjected to four or more biaxial stretching and moderate shrinkage, 4-6 water washings, and a pore-preserving treatment with a pore-preserving agent having a mass percentage concentration of 20-30%, thereby obtaining a hollow fiber membrane. Among them, the pore-forming agent is one or more of lithium chloride or sodium nitrite; the solvent is dimethyl sulfoxide, dimethylformamide, dimethylacetamide or N-methylpyrrolidone; the pore-preserving agent for pore-preserving treatment is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, isopentanol, ethylene glycol, and glycerol. The preparation method of the hollow fiber membrane 11 can be prepared according to the existing technology. After the hollow fiber membrane 11 is prepared and formed, if the hydrophilicity is poor, the prepared hollow fiber membrane can be subjected to plasma, chemical grafting or coating to introduce polar groups on the surface of the hollow fiber membrane 11 to improve the hydrophilicity.

[0053] like Figure 21 is a schematic diagram of an ascites protein extraction system according to the present invention. The ascites protein extraction system includes an ascites filter 100 and a concentrator 200. Both the ascites filter 100 and the concentrator 200 are arranged or installed horizontally, i.e., the ascites filter 100 and the concentrator 200 are horizontally positioned and fixed on an operating platform or mounted horizontally using a bracket. A physiological saline bag / ascites bag 101 is provided at the front end of the ascites filter 200. The physiological saline bag / ascites bag 101 is connected to the ascites inlet 7 of the ascites filter 100 by a pipeline 102, on which a valve 121 is provided. The filtrate outlet 8 of the ascites filter 100 is connected to the raw liquid inlet 201 of the concentrator 200 by a pipeline 103, on which a valve 131 is provided. The concentrate outlet 202 of the concentrator 200 is connected to a pump 206, with a valve 261 installed between them. A pipeline 207 connects the pump 206 to the concentrate collection device 204, with a valve 271 installed on it. A waste liquid outlet 205 is also provided on one side of the concentrator 200 housing. This outlet is connected to a negative pressure suction device 208, with a valve 251 installed between the outlet and the negative pressure suction device. The negative pressure suction device 208 also includes a waste liquid storage tank. No pressurizing device is installed at the front end of the ascites filter 200. The irrigating liquid inlet 9 of the ascites filter 100 is equipped with a valve 108, which can be connected to a manual syringe. The irrigating liquid outlet 10 of the ascites filter 100 is connected to the irrigating liquid recovery device 105 via a pipeline 104, with a valve 141 installed on it.

[0054] Concentrator 200 is also a hollow fiber membrane device, comprising a housing and a hollow fiber membrane bundle disposed within the housing. One end of the housing is a raw liquid inlet 201, which is connected to the filtrate outlet 8 of the ascites filter 100. The other end of the housing is a concentrated liquid outlet 202, which is connected to a pump 206. A waste liquid outlet 205 is provided on one side of the housing. The outer end of waste liquid outlet 205 is connected to a negative pressure suction device 208, and the inner end of waste liquid outlet 205 communicates with the internal cavity of the housing but not with the hollow channels of the hollow fiber membrane bundle of concentrator 200. Concentrator 200 also has a flushing liquid inlet 209 on one side. However, since concentrator 200 is only used to concentrate the protein-rich liquid filtered and collected by the ascites filter 100, removing excess water and some inorganic salts (electrolytes), and reducing the volume of the recovered protein-containing liquid, concentrator 200 is not easily clogged. Therefore, flushing of concentrator 200 is not required during an ascites protein extraction cycle. It should be noted that the ascites to be treated is an in vitro material extracted from the patient's body, and the system of the present invention is not directly connected to the human body.

[0055] The invention scheme and technical effects are described below in conjunction with specific embodiments of the present invention.

[0056] Example 1

[0057] The design parameters of the ascites filter 100 of this embodiment are as follows: the material composition of the hollow fiber membrane 11 (mass percentage, dry membrane): polysulfone PSU 55%, polypropylene 41.4%, PVP 3.6%. The membrane pore size is ≤0.285μm, and the membrane pores ≥0.25μm account for 30% of the total membrane pore area, of which the membrane pores ≥0.20μm account for 42% of the total membrane pore area. The diameter of the flushing liquid outlet 10 is 2.2cm, and the diameter of the flushing liquid inlet 9 is 1.1cm. The inner diameter of the filter cavity 2 is 4.4cm, the hollow fiber membrane filling rate is 35%, and the membrane filtration area is 1.4㎡. The installed length of the hollow fiber membrane 11 is 30cm, and the actual length of the hollow fiber membrane 11 is 33cm. The number of hollow fiber membranes 11 filled in the filter cavity is 7800.

[0058] Example 2

[0059] The design parameters of the ascites filter 100 of this embodiment are as follows: the material composition of the hollow fiber membrane 11 (mass percentage, dry membrane): polysulfone PSU 60%, polypropylene 36.8%, PVP 3.2%. After the hollow fiber membrane is manufactured, it is treated with plasma for hydrophilicity. The membrane pore size is ≤0.285μm, and the membrane pores ≥0.25μm account for 30% of the total membrane pore area, of which the membrane pores ≥0.20μm account for 50% of the total membrane pore area. The diameter of the flushing liquid outlet 10 is 2.2cm, and the diameter of the flushing liquid inlet 9 is 1.1cm. The inner diameter of the filter cavity 2 is 4.4cm, the hollow fiber membrane filling rate is 35%, and the membrane filtration area is 1.4㎡. The installed length of the hollow fiber membrane 11 is 30cm, and the actual length of the hollow fiber membrane 11 is 33cm. The number of hollow fiber membranes 11 filled in the filter cavity is 7800.

[0060] Example 3

[0061] The design parameters of the ascites filter 100 of this embodiment are as follows: the material composition of the hollow fiber membrane (mass percentage, dry membrane): polysulfone PSU 65%, polyethylene 32.2%, PVP 2.8%. After the hollow fiber membrane is manufactured, it is treated with plasma for hydrophilicity. The membrane pore size is ≤0.285μm, and the membrane pores ≥0.25μm account for 40% of the total membrane pore area, of which the membrane pores ≥0.20μm account for 65% of the total membrane pore area. The diameter of the flushing liquid outlet 10 is 2.2cm, and the diameter of the flushing liquid inlet 9 is 1.1cm. The inner diameter of the filter cavity 2 is 4.4cm, the hollow fiber membrane filling rate is 40%, and the membrane filtration area is 1.6㎡. The installed length of the hollow fiber membrane 11 is 30cm, and the actual length of the hollow fiber membrane 11 is 33cm. The number of hollow fiber membranes 11 filled in the filter cavity is 8914.

[0062] In order to test the extraction effect of the ascites filter 100 on ascites protein, a simulated ascites sample was prepared using bovine blood containing blood cell components. The preparation method is as follows: take 5L of bovine blood, add 50,000 units of the anticoagulant sodium heparin, and then use a centrifuge to centrifuge to obtain the plasma layer, red blood cell layer and each layer of solution of the buffy coat, and recover them separately. Next, the plasma layer is mixed with physiological saline, and protein is added to prepare simulated transudative ascites (hepatic ascites, non-cancerous ascites) of various concentrations. Then, white blood cells and red blood cells are added to the buffy coat, and then mixed with plasma to prepare simulated exudative ascites (cancerous ascites) of various concentrations. According to the above method, 3 simulated transudative ascites and 3 simulated exudative ascites samples as shown in Table 1 were prepared.

[0063] Table 1: Composition of simulated transudative ascites samples and simulated exudative ascites samples

[0064]

[0065]

[0066] use Figure 2 The system shown is used to recover and extract ascites protein. The operation process is as follows:

[0067] (1) Place the ascites filter 100 and concentrator 200 horizontally on an operating platform. Concentrator 200 is a conventional ultrafiltration (UF) membrane (pore size 1-5 nm), with a filtration cavity length of 30 cm and a membrane area of ​​1.5 m2. Ascites filter 100 is the filter of Examples 1-3.

[0068] (2) Place the saline bag 101 at a height of 40 cm on the operating platform, so that the saline enters the filter cavity 2 of the ascites filter 100 from the ascites inlet 7 of the filter 100 under gravity, and then the saline comes out from the flushing liquid outlet 10, thereby completing the flushing of the inside of the filter cavity 2 and the outside of the hollow fiber membrane 11. 1000 mL of saline is used for the flushing.

[0069] (3) Next, the flushing liquid outlet 10 is closed, and the valve 131 and the negative pressure suction device 208 between the ascites filter 100 and the concentrator 200 are opened, so that the physiological saline enters the ascites inlet 7 of the ascites filter 100 under gravity and exits the filtrate outlet 8. The saline is then sucked out from the waste liquid outlet 205 by the negative pressure suction device 208, thereby completing the flushing of the hollow channels of the hollow fiber membrane filaments 11 of the ascites filter 100. The flushing uses 1000 mL of physiological saline.

[0070] (4) The simulated ascites sample prepared above is placed in an ascites bag 101, which is hung at a height of 40 cm on the operating platform. The valve 121 between the ascites bag 101 and the ascites filter 100 is opened, and the negative pressure suction device 208 and the pump 206 connected to the concentrator 200 are opened at the same time. The working pressure of the negative pressure suction device 208 is adjusted, and the speed of the concentrated liquid output of the pump 206 is adjusted to 10-30 mL / min, so that the filtration pressure of the ascites filter 100 is 30-50 KPa. At this time, the ascites in the ascites bag 101 enters the filtration cavity 2 from the ascites inlet 7 of the ascites filter 100 under gravity and flows horizontally, and is filtered from the outside of the hollow fiber membrane filaments 11 to the inside of the hollow channel of the hollow fiber membrane filaments 11. Among them, the protein-containing filtrate penetrates into the interior of the hollow fiber membrane filament 11, and is discharged from the filtrate outlet 8 and enters the concentrator 200. After entering the concentrator 200, it flows in the hollow channel of the hollow fiber membrane bundle of the concentrator, and the excess water and electrolytes are filtered to the outside of the hollow fiber membrane bundle, and are discharged from the waste liquid outlet 205 under the operation of the negative pressure suction device 208, while the protein-containing concentrated liquid continues to remain in the hollow channel of the hollow fiber membrane bundle 11 of the concentrator 200, and is collected to the concentrated liquid collection device 204 under the drive of the pump 206, so as to realize the filtration and concentration of simulated ascites.

[0071] (5) When the outlet speed of the concentrated liquid outlet 202 drops to 50% of the initial set speed, it indicates that the hollow fiber membrane of the ascites filter 100 is clogged and a backwash operation is required. The backwashing process is as follows:

[0072] ① Close the valve 121 between the ascites bag 101 and the ascites inlet 7 of the filter 100 to keep the ascites filter 100 connected to the concentrator 200; manually inject 100 mL of normal saline into the flushing liquid inlet 9 of the ascites filter 100 by pushing the syringe, and use the injected normal saline to push the liquid containing protein inside the hollow fiber membrane filaments 11 of the ascites filter 100 into the concentrator 200 to continue concentrating and remove excess water and electrolytes, etc., to collect the concentrated protein solution.

[0073] ② After the previous step is completed, turn off the pump 206 and the negative pressure suction device 208, close the valve 131 between the ascites filter 100 and the concentrator 200, open the valve 121 between the ascites bag 101 and the ascites inlet 7 of the filter 100, and inject 200 mL of normal saline into the flushing fluid inlet 9 by manually pushing the syringe. The normal saline will push the ascites that has entered the filter cavity 2 back through the ascites inlet 7 and the pipeline 102 to the ascites bag 101 to avoid waste.

[0074] ③ After the previous step, close valve 121 between ascites bag 101 and filter ascites inlet 7. Open rinsing fluid outlet 10 and valve 141. Inject 50 mL of saline into rinsing fluid inlet 9 using a syringe. Repeat this process 10 times. The saline will penetrate the hollow fiber membranes 11 of ascites filter 100, flushing contaminants adhering to the outer pores or pores of the hollow fiber membranes 11 and sending them to rinsing fluid recovery device 105. Each injection of saline is at a pressure of approximately 60 kPa.

[0075] (6) After completing the above-mentioned flushing process, close the flushing liquid outlet 10 and the flushing liquid inlet 9 of the ascites filter 100, open the valve 121 between the ascites bag 101 and the ascites filter 100, open the valve 131 between the ascites filter 100 and the concentrator 200, turn on the pump 206 and the negative pressure suction device 208 connected to the concentrator 200, and continue to extract ascites protein.

[0076] The above 6 simulated ascites samples were Figure 2 The ascites protein extraction rate and clogging status after treatment with the system are recorded in Table 2.

[0077] Table 2: Processing of ascites samples using the ascites protein extraction system of the present invention

[0078]

[0079] Note: Filtration time does not include backwash time

[0080] From the test results in Table 2, it can be seen that the ascites protein extraction system and ascites filter of the present invention can achieve a protein recovery rate of more than 90% for different simulated ascites samples, and the protein recovery rate for most simulated ascites samples can exceed 90%.

[0081] Next, 10 L of simulated transudative ascites sample 2# and 10 L of simulated exudative ascites sample 5# were prepared, and 500 staphylococci / L were added to each sample as bacterial interferants. The same conditions as in Table 2 were used for ascites protein concentration and recovery. During the filtration of transudative ascites sample 2#, the system required one backwash, and during the filtration of simulated exudative ascites sample 5#, the system required two backwashes. The cumulative protein recovery and the number of staphylococci filtered out within the first 2 min of the first filtration and the first 2 min of subsequent filtration after each backwash were recorded. The statistical results are shown in Table 3.

[0082] Table 3: Filtration performance of ascites filter after initial filtration and backwashing

[0083]

[0084] The test results in Table 3 show that the ascites protein filtration and concentration system of the present invention maintains a stable protein recovery rate and harmful substance removal function after multiple rounds of backwashing. The hollow fiber membrane of the ascites filter does not easily increase in pore size after backwashing, and the retention accuracy can be maintained for a long time, effectively filtering out bacteria such as Staphylococcus and Escherichia coli. This proves that the hollow fiber membrane filaments 11 of the ascites filter 100 prepared by the present invention have good mechanical strength and toughness, and can maintain a stable filtration pore size and precise retention performance after multiple pressure operations such as backwashing.

[0085] In summary, the ascites filter of the present invention has high ascites protein recovery rate, good mechanical strength, toughness and anti-flushing deformation performance.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements, or when the technical features in the above embodiments do not conflict with each other, can be combined in the manner described in the embodiments, and these modifications, replacements or combinations do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ascites filter, characterized in that: include: A filter chamber is provided with a plurality of hollow fiber membranes, wherein the hollow fiber membranes are spaced apart from each other, and sealing materials are provided at both ends of the hollow fiber membranes to seal the space between the hollow fiber membranes and the space between the hollow fiber membranes and the inner wall of the filter chamber; The filter cavity includes a first end and a second end, the first end is provided with a flushing liquid inlet, and the second end is provided with a filtrate outlet; the two ends of the hollow fiber membrane filament form a distance with the first end and the second end respectively, the distance between the hollow fiber membrane filament and the first end of the filter cavity constitutes a flushing liquid inlet buffer zone, and the distance between the hollow fiber membrane filament and the second end of the filter cavity constitutes a filtrate outlet buffer zone; an ascites inlet is provided on one side of the filter cavity, the ascites inlet is communicated with the filter cavity and corresponds to between the two ends of the hollow fiber membrane filament, and the ascites inlet is far away from one end of the filtrate outlet; a flushing liquid outlet is also provided on one side of the filter cavity, the flushing liquid outlet is communicated with the filter cavity and corresponds to between the two ends of the hollow fiber membrane filament, and the flushing liquid outlet is arranged at an end far away from the flushing liquid inlet; Among them, the mass proportion of polysulfone resin in the hollow fiber membrane is 55-65%; the membrane pore size of the hollow fiber membrane is d, d≤0.285μm, and the membrane pores with a membrane pore size of more than 0.25μm account for ≥30% of the total membrane pore area.

2. The ascites filter according to claim 1, characterized in that The hollow fiber membrane comprises a first polymer material and a second polymer material, wherein the first polymer material is a polysulfone resin, which accounts for 55-65% by mass in the hollow fiber membrane; the remainder is a second polymer material, and the second polymer material is at least one of polyethylene, polypropylene, polyvinyl alcohol and polyacrylonitrile doped with 3-8wt% PVP.

3. The ascites filter according to claim 1, characterized in that In the hollow fiber membrane, the membrane pores with a pore diameter of 0.25 μm or more account for no more than 50% of the total membrane pore area; the membrane pores with a pore diameter of 0.20 μm or more account for 40-65% of the total membrane pore area.

4. The ascites filter according to claim 1, characterized in that The diameter of the flushing liquid outlet is D1, the diameter of the flushing liquid inlet is D2, and D1 / D2 is 1.8-2.

2.

5. The ascites filter according to claim 4, characterized in that Calculated based on the ratio of the total cross-section of the hollow fiber membrane to the cross-section of the filter cavity, the filling rate of the hollow fiber membrane in the filter cavity is 30-40%.

6. The ascites filter according to claim 5, characterized in that The filter cavity is a cylindrical filter cavity with an inner diameter of D3, D3=4-4.5cm, and the total specific surface area of ​​the hollow fiber membrane in the filter cavity is 1.3-2.0㎡; when the filling rate of the hollow fiber membrane in the filter cavity is 30-40%, D1 / D3 is 1 / 2-1 / 3.

7. The ascites filter according to claim 1, characterized in that The hollow fiber membrane has a certain degree of curvature; in the filter cavity, the distance between the two ends of the hollow fiber membrane is L1, and L1 is the length of the interval of the hollow fiber membrane inside the filter cavity; the actual length of the hollow fiber membrane is L2, and L2 / L1 is 1.05-1.

3.

8. The ascites filter according to claim 1, characterized in that The sealing material is a waterproof sealing adhesive, which is bonded to the outer surface of the end of the hollow fiber membrane and is used to seal the gaps between the hollow fiber membranes.

9. A system for extracting ascites protein, characterized in that: It includes the ascites filter and concentrator according to any one of claims 1 to 8, the filter and concentrator are both arranged or installed horizontally, the filtrate outlet of the ascites filter and the raw liquid inlet of the concentrator are connected by a pipeline, the concentrated liquid outlet of the concentrator is connected to a pump, and the concentrated liquid is introduced into a concentrated liquid collection device through the pump. A waste liquid outlet is also provided on one side of the concentrator, and the waste liquid outlet is connected to a negative pressure suction device; no pressurizing device is provided at the front end of the ascites filter.

10. The ascites protein extraction system according to claim 9, characterized in that: The concentrator is a hollow fiber membrane device, which includes a shell and a hollow fiber membrane bundle arranged inside the shell. One end of the shell is the raw liquid inlet, which is connected to the filtrate outlet of the ascites filter. The other end of the shell is the concentrated liquid outlet, which is connected to the pump. The waste liquid outlet is set on one side of the shell, and the outer end of the waste liquid outlet is connected to the negative pressure suction device. The inner end of the waste liquid outlet is connected to the interior of the shell but not to the hollow channel of the hollow fiber membrane bundle.

11. A method for extracting ascites protein, which is achieved by the ascites protein extraction system according to any one of claims 9 to 10, characterized in that: The extraction method comprises the following steps: S1. Place the ascites filter and concentrator horizontally on the operating platform; S2. Place the bag of normal saline at a height of 30-50 cm on the operating platform, allowing the normal saline to enter the filter cavity from the ascites inlet of the filter under gravity and exit from the rinsing liquid outlet, thereby completing the flushing of the interior of the filter cavity and the exterior of the hollow fiber membranes; then, close the rinsing liquid outlet, open the valve and negative pressure suction device between the ascites filter and the concentrator, allowing the normal saline to enter the ascites inlet of the filter under gravity and exit from the filtrate outlet, thereby completing the flushing of the interior of the hollow fiber membranes of the ascites filter; S3. Place the ascites bag 30-50 cm above the operating platform, open the valves on the ascites bag and the ascites filter, and simultaneously start the negative pressure suction device and pump connected to the concentrator. Adjust the operating pressure of the negative pressure suction device and the pump speed to 10-30 mL / min so that the filtration pressure of the filter is 225-450 mmHg. Ascites enters the filter cavity from the ascites inlet under gravity, and the protein-containing filtrate is discharged from the filtrate outlet and enters the concentrator. After entering the concentrator, it flows in the hollow channels of the hollow fiber membrane bundles of the concentrator. Excess water and dielectric are filtered to the outside of the hollow fiber membrane bundles and discharged from the waste liquid outlet under the operation of the negative pressure suction device. The protein-containing concentrate remains inside the hollow channels of the hollow fiber membrane bundle and enters the concentrate collection device under the drive of the pump; S4. When the outlet velocity of the concentrated liquid drops to 50% of the initial velocity, backwashing is performed. The backwashing process is as follows: S41. Close the valve between the ascites bag and the ascites inlet of the filter to maintain communication between the filter and the concentrator; inject physiological saline into the flushing fluid inlet to push the protein-containing liquid inside the hollow fiber membrane of the ascites filter into the concentrator for further concentration processing; S42. After the treatment is completed, turn off the pump and the negative pressure suction device, close the valve between the filter and the concentrator, open the valve between the ascites bag and the ascites inlet of the filter, inject normal saline into the flushing fluid inlet, and use the normal saline to push the ascites that has entered the filter cavity back into the ascites bag; S43. Close the valve between the ascites bag and the ascites inlet of the filter, open the flushing fluid outlet, and inject normal saline into the flushing fluid inlet. The normal saline will penetrate from the inside of the hollow fiber membrane of the filter to the outside, flushing out the blockage outside the hollow fiber membrane. Repeat the injection of normal saline 8-12 times, and the pressure of the injected normal saline should not exceed 500 mmHg. S5. After the flushing is completed, close the flushing fluid outlet and flushing fluid inlet, open the valve between the ascites bag and the filter, open the valve between the ascites filter and the concentrator, turn on the pump and negative pressure suction device connected to the concentrator, and continue to extract ascites protein according to the method of S3.

12. The method for extracting ascites protein according to claim 11, wherein The operation of injecting normal saline from the flushing fluid inlet is to use a syringe for manual injection.

Images