Hollow fiber membrane filament detection device and detection method thereof

Abstract

The application relates to a hollow fiber membrane filament detection device and a detection method thereof, and belongs to the technical field of membrane filament detection. The detection method comprises the following steps: S1, connecting a to-be-detected membrane filament to a membrane filament detection device; S2, feeding a feed liquid into the to-be-detected membrane filament, controlling the pressure in the detection device, so that the average pressure before and after the feed liquid permeates the membrane filament is equal to 1 Bar, and collecting the permeate of the membrane filament after the pressure is stabilized; and S3, taking samples of the permeate and the feed liquid of the membrane filament in step S2, detecting the samples on a total organic carbon analyzer, and obtaining the total organic carbon content C P of the permeate and the total organic carbon content C F of the feed liquid; and calculating the retention rate value of the membrane filament through a retention rate formula R=(C F -C P ) / C F *100%. The detection method is simple in operation, can accurately detect the retention rate of the membrane filament quickly, and is high in detection efficiency; and the detection device matched with the detection method is simple in structure and easy to operate.

Description

Technical Field

[0001] This application relates to the field of membrane fiber detection technology, and in particular to a hollow fiber membrane fiber detection device and its detection method. Background Technology

[0002] Hollow fiber membranes are fibrous membranes with self-supporting properties. Membrane separation technology is a widely used separation technique for solution separation, concentration, and purification. It utilizes a thin membrane with selective permeability as the separation medium. The membrane wall is densely covered with micropores. Under certain pressure, the feed solution passes through one side of the membrane. The solvent and small molecule solutes permeate through the membrane wall as the permeate, while larger molecule solutes are retained by the membrane, thereby achieving the purpose of substance separation and concentration.

[0003] Currently, before hollow fiber membranes can be put into online production, they need to be inspected according to relevant standards to determine whether the produced membrane fibers meet the usage requirements. Only membrane fibers that meet the requirements can be used to make modules and put into use. Typically, a small number of hollow fiber membrane fibers are cast into hollow fiber modules, and the quality of the membrane fibers is judged by testing the parameters of the modules. This method takes 2-3 days to obtain results, making it impossible to adjust the hollow fiber membrane fiber production process in a timely manner, thus affecting product quality. Currently, the membrane fiber testing devices used by a few companies have limited functions, and due to unreliable membrane fiber fixing methods and poor sealing, the consistency of test results is not ideal.

[0004] In the biopharmaceutical industry, the main testing items for hollow fiber membranes include flux, rejection rate (including protein rejection, cytochrome rejection, and endotoxin rejection), membrane fiber strength, and resilience. For protein and cytochrome rejection rate testing, ultraviolet (UV) spectrophotometry is commonly used for measurement and calculation. When using UV spectrophotometry, multiple standard concentration solutions need to be prepared first. The sample concentration must be within the concentration range of the standard solutions and of the same order of magnitude. For example, if the sample concentration is approximately 5 mg / L, at least five standard solutions in the range of 0-10 mg / L are needed to accurately measure the sample concentration. When the sample concentration is unknown or the prepared standard solutions do not cover the sample concentration, the measurement data will have a large deviation; if the concentration order of the standard solutions differs significantly from the actual sample concentration, the measurement data will also be inaccurate. UV spectrophotometers analyze substances by measuring the absorption of radiation in the ultraviolet spectral region by molecules. Their light source is prone to decay, and the standard solution curve needs to be recalibrated after a period of time. The requirements for cuvettes in ultraviolet spectrophotometry are very high; the photosensitive surface must be free of any scratches or contact with surfaces that have been touched. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide a method for detecting hollow fiber membrane filaments, thereby improving the technical problems of complex operation, slow efficiency, complex supporting device structure, and limited detection items in existing membrane filament detection methods.

[0006] This application provides a method for detecting hollow fiber membrane filaments, including:

[0007] S1. Connect the membrane fiber to be tested to the membrane fiber detection device;

[0008] S2. Pass the feed liquid into the membrane fiber to be tested, control the pressure in the detection device so that the average pressure of the feed liquid before and after passing through the membrane fiber is equal to 1 Bar, and collect the permeate from the membrane fiber after the pressure stabilizes.

[0009] S3. Sampling step S2 involves taking samples of the permeate and feed liquid from the membrane fibers and analyzing them using a total organic carbon analyzer to obtain the total organic carbon content (C) in the permeate. P and the total organic carbon content (C) in the feed liquid F ; using the retention rate formula R = (C F -C P ) / C F *The retention rate of the membrane fibers is calculated at 100%;

[0010] The detection device includes:

[0011] Gas source;

[0012] Pressure control system; gas source and pressure control system pipeline connection;

[0013] The measuring component includes a first liquid storage container, a second liquid storage container, a liquid storage cup, and a balance disposed at the bottom of the liquid storage cup; the second liquid storage container is connected to both a gas source and a pressure control system.

[0014] A membrane fiber connector is located at both ends of the membrane fiber to be tested. One end of the membrane fiber is connected to the first liquid storage container, and the other end is connected to the pressure control system. A liquid storage cup is located at the bottom of the membrane fiber to be tested and is used to collect the permeate from the membrane fiber. The first liquid storage container is used to hold the feed liquid.

[0015] The power unit is connected at one end to the first liquid storage container and at the other end to the pressure control system.

[0016] This detection method is simple to operate and can quickly and accurately detect the membrane fiber rejection rate with high detection efficiency. The second liquid storage container can be filled with water and other media to facilitate the measurement of membrane fiber flux and the cleaning of pipelines after use, so as to prevent test media residue from clogging the pipeline.

[0017] In some embodiments of this application, in step S2, the permeate from the membrane fibers is collected after the pressure has stabilized for 5-10 minutes. After the pressure has stabilized for 5-10 minutes, the membrane fibers are completely wetted by the medium, and the pores are filled with the medium. The measured results can effectively reflect the parameter performance of the membrane fibers.

[0018] In some embodiments of this application, the diameter of the membrane filament is 0.3-1.5 mm, and the effective length of the membrane filament is 10-150 cm. Within this effective length range, installation and testing are more convenient, and it is more conducive to collecting permeate. The obtained data can characterize the parameters of all membrane filaments. In some embodiments of this application, the membrane filament connector includes: a locking assembly, which includes a first locking member and a second locking member that are threaded together; the first locking member has a first through hole, and the second locking member has a second through hole, with the first through hole and the second through hole corresponding to each other; the first through hole is a tapered hole; and a traction assembly, which includes a first retaining ring disposed between the first locking member and the second locking member. The first retaining ring includes an annular base and multiple clamping portions connected to the base. The multiple clamping portions are used to limit the inner diameter of the first retaining ring, and the clamping portions can be embedded in the tapered hole and abut against the hole wall of the tapered hole to change the inner diameter of the first retaining ring. With the above-mentioned membrane filament connector, the membrane filament and the needle can be firmly fixed in the membrane filament connector, with high sealing performance, and the measurement of the project can be completed under high pressure.

[0019] In some embodiments of this application, the detection device further includes a needle that can move along the extension direction of the first through hole and the second through hole, and the diameter of the needle is smaller than the diameter of the membrane filament.

[0020] In some embodiments of this application, the needle is detachably connected to a first through hole on the side of the first locking member away from the second locking member.

[0021] The membrane fiber itself is highly flexible. To better secure it to the membrane fiber connector, during use, the needle can be inserted into the membrane fiber first, and then the needle part can be inserted into the first through hole. The membrane fiber will also enter the membrane fiber connector along with the needle. When the overlapping area of ​​the needle and the membrane fiber reaches the clamping part of the first retaining ring, the second locking member is tightened. Under the action of external force, the clamping part of the first retaining ring will gradually abut against the inner wall of the first through hole, and the inner diameter of the opening of the clamping part will gradually decrease until the needle and the membrane fiber no longer move relative to each other in the first retaining ring, thus securing the needle and the membrane fiber firmly to the membrane fiber connector.

[0022] In some embodiments of this application, the traction assembly further includes a second retaining ring, which includes an annular base and a snap-fit ​​portion connected to the base, wherein the base of the first retaining ring is in contact with the base of the second retaining ring.

[0023] In some embodiments of this application, the base is threaded, and the second retaining ring is threadedly connected to the second locking member.

[0024] In some embodiments of this application, the snap-fit ​​portion is conical, and the second locking member has a snap-fit ​​groove that matches the snap-fit ​​portion.

[0025] In use, the overlapping area of ​​the membrane fiber and the needle is moved to the clamping part of the first retaining ring. Then, the base of the second retaining ring is brought into contact with the base of the first retaining ring. The locking groove of the second locking member is then moved to the conical locking part of the second retaining ring, so that the second retaining ring is partially fixed in the second locking member. Then, the second locking member is tightened with force. At this time, the second retaining ring is not easy to fall off and also plays a role in limiting and guiding. When the second retaining ring is squeezed by the external force from the second locking member, the second retaining ring will transfer the external force to the first retaining ring, so that the clamping part of the first retaining ring abuts against the inner wall of the first through hole, thereby narrowing the opening of the clamping part and clamping the membrane fiber and the needle.

[0026] In some embodiments of this application, multiple clamping portions are spaced apart. This spaced-apart arrangement of multiple clamping portions facilitates better adjustment of the opening inner diameter of the first retaining ring. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 An exploded view of the membrane fiber connector provided in this application;

[0029] Figure 2 A cross-sectional view of the membrane fiber connector provided in this application in its usage state;

[0030] Figure 3 A cross-sectional view of the membrane fiber connector provided in this application;

[0031] Figure 4 A top view of the membrane fiber connector provided in this application;

[0032] Figure 5 This application provides a schematic diagram of the structure of the second card ring;

[0033] Figure 6 A cross-sectional view of the second retaining ring provided in this application;

[0034] Figure 7 A schematic diagram of the hollow fiber membrane filament detection device provided in this application;

[0035] Figure 8 This is a schematic diagram of the hollow fiber membrane filament detection device and TOC instrument provided in Embodiment 1 of this application.

[0036] Icons: 100-Membrane filament connector; 101-Second locking element; 1021-First through hole; 1022-Second through hole; 103-First retaining ring; 1031-Clamping part; 104-Second retaining ring; 105-First locking element; 1051-Base; 1052-Locking block; 106-Needle; 200-Hollow fiber membrane filament; 301-Reservoir cup; 302-Balance; 400-First reservoir container; 500-Power assembly; 600-Second reservoir container. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this application, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0042] Figure 7 Schematic structural diagram of the hollow fiber membrane filament 200 detection device provided for this application; Figure 8 Schematic structural diagram of the hollow fiber membrane filament 200 detection device provided in Embodiment 1 of this application in combination with a TOC analyzer. Please refer to Figures 7-8 , this embodiment provides a method for detecting a hollow fiber membrane filament 200, including the following steps:

[0043] First, connect the membrane filament to be tested to the membrane filament detection device, then introduce the feed liquid into the membrane filament to be tested, control the pressure in the detection device so that the average pressure before and after the membrane filament of the feed liquid is equal to 1 Bar, and collect the permeate of the membrane filament after the pressure is stable; finally, take samples of the permeate and feed liquid of the membrane filament in step S2 and detect them on a total organic carbon analyzer to obtain the total organic carbon content C in the permeate P and the total organic carbon content C in the feed liquid F ; through the rejection rate formula R=(C F -C P ) / C F *100% to calculate the rejection rate value of the membrane filament. When the rejection rate > 90%, the molecular weight of the solution is the rejection molecular weight of the membrane filament.

[0044] This detection method is simple to operate, can quickly and accurately detect the rejection rate of the membrane filament, and has high detection efficiency; the detection device supporting this detection method has a simple structure and is easy to operate. Among them, the membrane filament is connected to the device through a membrane filament connector, and the membrane filament can be firmly fixed in the membrane filament connector with high sealing performance. Therefore, the membrane filament will not fall off from the detection device due to excessive pressure, and the project can be measured under high pressure. Water and other media can be filled in the second liquid storage container to facilitate the measurement of the membrane filament flux and the cleaning of the pipeline after the device is used, so as to avoid the residue of the test medium and blockage of the pipeline. This device can quickly and accurately detect multiple items such as the rejection rate, rejection molecular weight, flux, and bubble point pore size of a single membrane filament, and is less affected by the outside world during testing with high precision.

[0045] In some embodiments, in step S2, start to collect the permeate of the membrane filament after the pressure is stable for 5 - 10 minutes. After the pressure is stable for 5 - 10 minutes, at this time, the inside of the membrane filament is completely infiltrated with the medium, and the pores are filled with the medium, and the measured results can effectively reflect the parameter performance of the membrane filament.

[0046] In some embodiments, the diameter of the membrane fibers is 0.3-1.5 mm, and the effective length of the membrane fibers is 10-150 cm. For example, the diameter of the membrane fibers includes, but is not limited to, 0.3 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, and 1.5 mm; the effective length of the membrane fibers includes, but is not limited to, 10 cm, 30 cm, 50 cm, 60 cm, 70 cm, 80 cm, 100 cm, 120 cm, 130 cm, 140 cm, and 150 cm. Within this effective length range of the membrane fibers, installation and testing are more convenient, and it is more conducive to collecting the permeate; the data obtained can characterize the parameters of all membrane fibers.

[0047] The detection device used in the above detection method is described below.

[0048] The testing device includes: a gas source, a pressure control system, a measuring component, a membrane fiber connector 100, a liquid storage cup 301, and a power component 500; wherein, the gas source is connected to the pressure control system via pipeline; the measuring component includes a first liquid storage container 400, a liquid storage cup 301, and a balance 302 disposed at the bottom of the liquid storage cup 301; the membrane fiber connector 100 is disposed at both ends of the membrane fiber to be tested, one end of the membrane fiber is connected to the first liquid storage container 400, and the other end is connected to the pressure control system; the liquid storage cup 301 is disposed at the bottom of the membrane fiber to be tested and is used to collect the permeate from the membrane fiber, and the first liquid storage container 400 is used to hold the feed liquid; the power component 500 is connected at one end to the first liquid storage container 400 and at the other end to the pressure control system.

[0049] The membrane fiber and needle 106 can be firmly fixed in the membrane fiber connector 100, ensuring high sealing performance and allowing for measurement under high pressure. Furthermore, this device can quickly and accurately detect parameters such as the rejection rate, molecular weight cutoff, and bubble point pore size of a single membrane fiber, with minimal external influence and high accuracy during testing.

[0050] In some embodiments, the power assembly 500 can be a device such as a pump that can provide a power source.

[0051] In some embodiments, the pressure control system includes a plurality of pressure regulating valves and a pressure gauge. The device is provided with a plurality of pressure regulating valves (e.g., Figure 7 or Figure 8 The V1, V2, V3, and V4 valves can be adjusted to test multiple items as needed, such as molecular weight cutoff, bubble point, and pore size. Multiple pressure gauges (e.g., V1, V2, V3, V4) can be installed in the pipeline. Figure 7 or Figure 8 PG1 and PG2 in the pipeline can realize real-time pressure monitoring in different pipelines.

[0052] In some embodiments, the device further includes a second liquid storage container 600, which is interconnected with a gas source and a pressure control system.

[0053] In the above technical solution, the liquid storage cup 301 is mainly used to store the liquid flow rate through the hollow fiber membrane filament 200, while the balance 302 is used to determine the weight of the liquid in the liquid storage cup 301. The second liquid storage container 600 can be filled with water and other media to facilitate the measurement of membrane flux and the cleaning of pipelines after use, so as to prevent test media residue from clogging the pipelines.

[0054] In some embodiments, the device further includes multiple TOC analyzers. During use, a sampling tube can be connected to each of the first liquid storage container 400 and the liquid storage cup 301, and then connected to an online TOC analyzer with an appropriate range. This enables real-time TOC detection and data acquisition; the rejection rate can be calculated in real-time via an industrial computer or PLC. The TOC analyzer is simple to operate, has low operational difficulty and requirements, and offers high accuracy.

[0055] Based on the above-mentioned detection device, the detection methods for some items that the device can measure will be introduced below.

[0056] (1) Flux Measurement

[0057] Fill the second liquid storage container 600 with pure water. Adjust the air pressure using a pressure reducing valve to force the pure water out of the second liquid storage container 600 to the hollow fiber membrane filament 200. Secure both ends of the membrane filament with membrane filament connectors 100. Open valves V1 and V4, and close the other valves. Adjust the air source pressure until the average pressure before and after the membrane is approximately 1 Bar, i.e., (PG1+PG2) / 2 = 1 Bar. After the liquid flow rate through the hollow fiber membrane filament 200 stabilizes, begin measuring the increase in permeate volume. Use the tare function of the electronic balance 302 to measure the increase in liquid weight in the beaker over a certain period. Then, calculate the flux of the membrane filament by measuring its inner diameter and length (refer to national standard: GB / T 32360-2015 Ultrafiltration Membrane Test Method). Using this method, test results can be obtained within 1-2 hours.

[0058] (2) Measurement of bubble point pressure

[0059] The second liquid storage container 600 is empty, and the liquid storage cup 301 is filled with pure water, covering the entire membrane fiber. Open V1 and close other valves; slowly increase the gas pressure until the first continuous bubble appears in the liquid in the beaker, and record the current pressure value; then calculate the current maximum pore size of the membrane fiber using the calculation formula (refer to national standard: GB / T 32361-2015 Separation Membrane Pore Size Test Method Bubble Point and Average Flow Rate Method).

[0060] (3) Measuring the retention rate

[0061] A solution of a specific molecular weight is placed in the first storage container 400. Pumps V1 and V3 are turned on to circulate the solution and ensure uniformity. After 5 minutes, valves V2 and V4 are opened, and valves V3 and V4 are slowly adjusted until the average pressure before and after the membrane is approximately 1 Bar, i.e., (PG1 + PG2) / 2 = 1 Bar. After the system stabilizes for 10 minutes, the permeate from the membrane fibers is collected. Simultaneously, samples of the permeate and the feed solution in the first storage container 400 are taken and analyzed on a TOC (Total Organic Carbon) analyzer to determine the total organic carbon concentration in the two solutions. The obtained data are labeled as C. F (Total organic carbon content in feed liquid), C P (Total organic carbon content in the permeate). Retention rate R = (C F -C P ) / C F *100%.

[0062] The inventors discovered that using different analyzers for permeate and feed liquid introduces instrument errors, leading to deviations in the test results. Therefore, the inventors further analyzed the permeate and feed liquid using the same total organic carbon analyzer. The inventors also discovered that the detection time for permeate and feed liquid affects the detection accuracy; therefore, the inventors further analyzed the permeate and feed liquid simultaneously using the same total organic carbon analyzer.

[0063] Furthermore, the above-mentioned membrane fiber connector will be described in detail below.

[0064] Figure 1 An exploded view of the diaphragm fiber connector 100 provided in this application; Figure 2 A cross-sectional view of the membrane fiber connector 100 provided in this application in its usage state; Figure 3 A cross-sectional view of the membrane filament connector 100 provided in this application; Figure 4 A top view of the diaphragm connector 100 provided in this application;

[0065] Figure 5 This is a schematic diagram of the structure of the second card ring 104 provided in this application; Figure 6 A cross-sectional view of the second ring 104 provided in this application; please refer to Figures 1-6 .

[0066] The aforementioned diaphragm connector 100 includes a locking assembly and a traction assembly. The locking assembly includes a first locking member 105 and a second locking member 101 threadedly connected to each other. The first locking member 105 has a first through hole 1021, and the second locking member 101 has a second through hole 1022. The first through hole 1021 and the second through hole 1022 are positioned correspondingly. The first through hole 1021 is a tapered hole. Further, the traction assembly includes a first retaining ring 103 disposed between the first locking member 105 and the second locking member 101. The first retaining ring 103 includes an annular base and a plurality of clamping portions 1041 connected to the base. The plurality of clamping portions 1041 are used to define the inner diameter of the first retaining ring 103. The clamping portions 1041 can be embedded in the tapered hole and abut against the wall of the tapered hole to change the inner diameter of the first retaining ring 103.

[0067] In use, the membrane fiber enters the first retaining ring 103 through the first through hole 1021, moving the membrane fiber to a suitable position. Then, the second locking member 101 is tightened. During this process, under the action of external force, the clamping part 1041 of the first retaining ring 103 gradually moves closer to the first through hole 1021 of the first locking member 105. The first through hole 1021 is conical, and the clamping part 1041 can be embedded in the conical hole and abut against the wall of the conical hole. As a result, the opening of the clamping part 1041 will shrink due to the pressure, and the inner diameter of the opening will become smaller, thereby clamping the membrane fiber. In addition, the first locking member 105 also plays a limiting and guiding role for the retaining ring. Finally, the membrane fiber can be quickly locked in the membrane fiber connector 100 by the cooperation of the first locking member 105 and the second locking member 101. By using the membrane fiber connector 100 to lock the membrane fiber, the sealing performance is high and the membrane fiber is not easy to fall off.

[0068] In some embodiments, the membrane fiber connector 100 further includes a needle 106, which is detachably connected to a first through hole 1021 on the side of the first locking member 105 away from the second locking member 101. The needle 106 is movable along the extending direction of the first through hole 1021 and the second through hole 1022, and the diameter of the needle 106 is smaller than the diameter of the membrane fiber. Because the diameter of the needle 106 is smaller than the diameter of the membrane fiber, the needle 106 can be inserted into the membrane fiber. The membrane fiber itself is highly flexible. In order to better fix it in the membrane fiber connector 100, during use, the needle 106 can be inserted into the membrane fiber first, and then the part of the needle 106 can be inserted into the first through hole 1021. The membrane fiber will also enter the membrane fiber connector 100 along with the needle 106. When the overlapping area of ​​the needle 106 and the membrane fiber reaches the clamping part 1041 of the first retaining ring 103, the second locking member 101 is tightened. Under the action of external force, the clamping part 1041 of the first retaining ring 103 will gradually abut against the inner wall of the first through hole 1021, and the inner diameter of the opening of the clamping part 1041 will gradually decrease until the needle 106 and the membrane fiber do not move relative to each other in the first retaining ring 103, thus achieving the firm fixation of the needle 106 and the membrane fiber in the membrane fiber connector 100.

[0069] In some embodiments, the first locking member includes a base 1051 and a locking block 1052 connected to the base 1051. The locking block 1052 has a first through hole 1021. The base 1051 has an external thread, and the second locking member has an internal thread that matches the external thread. In use, the needle 106 and the membrane wire can be quickly and accurately locked into the membrane wire connector 100 through the threaded connection between the first locking member and the second locking member.

[0070] In some embodiments, the traction assembly further includes a second retaining ring 104, which includes an annular base and a snap-fit ​​portion connected to the base. The base of the first retaining ring 103 is in contact with the base of the second retaining ring 104. The base of the second retaining ring 104 is provided with threads, and the second retaining ring 104 is threadedly connected to the second locking member 101. The snap-fit ​​portion is conical, and the second locking member 101 is provided with a snap-fit ​​groove that is adapted to the snap-fit ​​portion.

[0071] In use, the overlapping area of ​​the membrane filament and needle 106 is moved to the clamping part 1041 of the first retaining ring 103. Then, the base of the second retaining ring 104 is brought into contact with the base of the first retaining ring 103. The locking groove of the second locking member 101 is then moved to the conical locking part of the second retaining ring 104, so that the second retaining ring 104 is first partially fixed in the second locking member 101. Then, the second locking member 101 is tightened with force. At this time, the second retaining ring 104 is not easy to fall off and also plays a role in limiting and guiding. When the second retaining ring 104 is squeezed by the external force from the second locking member 101, the second retaining ring 104 will transmit the external force to the first retaining ring 103, so that the clamping part 1041 of the first retaining ring 103 abuts against the inner wall of the first through hole 1021, thereby narrowing the opening of the clamping part 1041, thereby clamping the membrane filament and needle 106.

[0072] In some embodiments, a plurality of clamping portions 1041 are spaced apart. The spaced arrangement of the plurality of clamping portions 1041 facilitates better adjustment of the inner diameter of the opening of the first retaining ring 103.

[0073] In some embodiments, the needle can adopt a Luer interface type. During use, after the needle and membrane wire are fixed in the membrane wire connector, the needle portion can be connected using a corresponding Luer connector, as detailed in GB / T 1962 "Syringes, Injection Needles and Other Medical Devices 6% (Luer) Conical Connectors". The Luer connector is then connected to the pressure pipeline via a sealing thread, thus enabling communication between the needle and the pressure pipeline, allowing the membrane wire connector to also be connected to the pressure detection system pipeline. Subsequently, the liquid in the first reservoir can enter the needle through the Luer connector and then flow into the membrane wire, thereby completing the test.

[0074] Example 1

[0075] For the protein retention rate determination, please refer to the following reference for the detection device used. Figure 8 .

[0076] The method for determining protein retention rate includes the following steps:

[0077] 1. Take 1g of bovine serum albumin with an average molecular weight of 67KD, add it to 1L of purified water, dissolve it completely and stir well, then pour it into the first storage container 400.

[0078] 2. Open valve V3, close all other valves, and turn on power unit 500 to circulate the liquid;

[0079] 3. After 5 minutes, open valve V2 and slowly reduce the opening of valve V3 until the pressure gauge PG1 reading is greater than 1 bar.

[0080] 4. Slowly open valve V4 and adjust pressure gauge PG2 until PG1 + PG2 = 2 Bar;

[0081] 5. Continue running in this state for 5 minutes, then replace with a new reservoir 301 below the membrane fibers to collect the solution that has permeated through the membrane fibers. Collect approximately 50 mL.

[0082] 6. Using two clean pipettes, take 30 mL of liquid samples from the first liquid storage container 400 and the liquid storage cup 301 respectively, and label the corresponding sample bottles as feed liquid and permeate liquid;

[0083] 7. Place the sample vials from step 6 into a TOC analyzer for testing, and measure the total organic carbon concentration in the two solutions. Label the obtained data as C. F (Total organic carbon content in feed liquid), C P (Total organic carbon content in the permeate). Retention rate R = (C F -C P ) / C F *100%.

[0084] The aforementioned TOC analyzer uses Shimadzu's TOC-L series and is equipped with an autosampler, allowing for the simultaneous loading and automatic detection of multiple samples. The TOC-L analyzer uses the platinum catalytic combustion NDIR method to determine total organic carbon, with a measurement range of 0-30000 mg / L and an accuracy of ≤1.5%. Due to the wide measurement range and high accuracy of the TOC analyzer, the highest membrane fiber rejection rate can reach 99.99%.

[0085] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for detecting hollow fiber membrane filaments, characterized in that, include: S1. Connect the membrane fiber to be tested to the membrane fiber detection device; S2. Pass the feed liquid into the membrane fiber to be tested, control the pressure in the detection device so that the average pressure of the feed liquid before and after passing through the membrane fiber is equal to 1 Bar, and collect the permeate from the membrane fiber after the pressure stabilizes. S3. The permeate from the membrane fibers and the feed solution in sampling step S2 are analyzed using a total organic carbon analyzer to obtain the total organic carbon content C in the permeate. P and the total organic carbon content (C) in the feed liquid F ; using the retention rate formula R=(C F - C P ) / C F *The retention rate of the membrane fibers is obtained by 100%; The detection device includes: Gas source; A pressure control system, wherein the gas source is connected to the pressure control system pipeline; The measuring component includes a first liquid storage container, a second liquid storage container, a liquid storage cup, and a balance disposed at the bottom of the liquid storage cup; the second liquid storage container is connected to the gas source and the pressure control system respectively. A membrane fiber connector is provided at both ends of the membrane fiber to be tested. One end of the membrane fiber is connected to the first liquid storage container, and the other end is connected to the pressure control system. The liquid storage cup is provided at the bottom of the membrane fiber to be tested and is used to collect the permeate of the membrane fiber. The first liquid storage container is used to hold the feed liquid. A power assembly, one end of which is connected to the first liquid storage container and the other end of which is connected to the pressure control system; The filament connector includes: A locking assembly includes a first locking member and a second locking member that are threadedly connected to each other. The first locking member has a first through hole, and the second locking member has a second through hole. The first through hole and the second through hole are positioned corresponding to each other. The first through hole is a tapered hole. A traction assembly includes a first retaining ring disposed between a first locking member and a second locking member. The first retaining ring includes an annular base and a plurality of clamping portions connected to the base. The plurality of clamping portions are used to define the inner diameter of the first retaining ring. The clamping portions can be fitted into the tapered hole and abut against the hole wall of the tapered hole to change the inner diameter of the first retaining ring. The membrane fiber connector also includes a needle that is inserted into the membrane fiber; the liquid in the first liquid reservoir enters the needle through a Luer connector and then flows into the membrane fiber.

2. The detection method according to claim 1, characterized in that, In step S2, the permeate from the membrane fibers is collected after the pressure has stabilized for 5-10 minutes.

3. The detection method according to claim 1, characterized in that, The diameter of the membrane filament is 0.3-1.5 mm, and the effective length of the membrane filament is 10-150 cm.

4. The detection method according to claim 1, characterized in that, The needle can move along the extension direction of the first through hole and the second through hole, and the diameter of the needle is smaller than the diameter of the membrane filament.

5. The detection method according to claim 4, characterized in that, The needle is detachably connected to the first through hole on the side of the first locking member away from the second locking member.

6. The detection method according to claim 5, characterized in that, The traction assembly further includes a second retaining ring, which includes an annular base and a snap-fit ​​portion connected to the base, wherein the base of the first retaining ring is in contact with the base of the second retaining ring.

7. The detection method according to claim 6, characterized in that, The base is threaded, and the second retaining ring is threadedly connected to the second locking member.

8. The detection method according to claim 6, characterized in that, The snap-fit ​​part is conical, and the second locking member has a snap-fit ​​groove that is adapted to the snap-fit ​​part.

9. The detection method according to claim 1, characterized in that, Multiple clamping parts are spaced apart.

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