Device and method for testing integrity of large-diffusion-flow membrane-coated filter

Abstract

The invention relates to a device and a method for testing the integrity of a large-diffusion-flow membrane-coated filter. The method comprises the following steps: connecting an air inlet to an air inlet of an automatic filter integrity tester; connecting a gas outlet of an automatic filter integrity tester to a gas inlet of a buffer tank; a gas outlet of the buffer tank is connected to a feed liquid inlet of the membrane bag filter; a feed liquid outlet is formed in the other side of the membrane bag filter, and the buffer tank is used for stabilizing and buffering the pressure in the testing process; the accuracy and the reliability of a test result are ensured by externally connecting a buffer tank with a proper volume and optimizing a test program; the production cost of the buffer tank is low; the test cost is reduced; the electronic recording of the test result is realized, and the problem that the gas pressure in the upstream volume drops too fast and the test cannot be successful in the test process because the diffusion flow is too large and the upstream volume is relatively small is solved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of filtration technology, and in particular to an optimization method for successfully completing integrity testing of a large diffusion flow membrane filter using an automatic filter integrity tester. Background Art

[0002] Membrane filters are widely used in the pharmaceutical, bioengineering, food and beverage, and other industries for liquid filtration and separation. Filter integrity testing is a critical step in ensuring membrane filter performance. A filter integrity tester is typically used to determine filter integrity by measuring gas diffusion flow.

[0003] In practical applications, due to its structural characteristics, the large diffusion flow membrane filter has a very large flux, so in practical applications, a smaller amount of membrane packages can meet the actual needs (for example, 6 membrane packages with a filtration area of ​​15m 2 The upstream volume of the system is relatively small (generally less than 5000ml), while the diffusion flow of the large diffusion flow membrane filter is extremely large, with an upper limit of up to 1600ml / min.m 2 When using an automatic filter integrity tester to perform a diffusion flow test, a certain volume of gas pressure needs to be isolated upstream of the filter. Gas molecules will diffuse through the pores of the wet membrane to the downstream, and the gas pressure in the upstream volume will drop accordingly.

[0004] According to Fick's first law, the diffusion flux, J, is proportional to the concentration gradient: J = -D*ΔC / L, where D is the diffusion coefficient, ΔC is the concentration gradient, and L is the membrane thickness. Under the ideal gas assumption, the concentration, C, is proportional to the pressure, P (C = P / RT). Therefore, the diffusion flux is proportional to the pressure difference, ΔP, between the upstream and downstream sides of the membrane. If the upstream test pressure drops significantly during the test, ΔP decreases, and the diffusion flux decreases accordingly, causing the test result to underestimate the true diffusion flux and distort the results.

[0005] At the same time, relevant regulations also have relevant requirements for pressure changes during filter diffusion flow testing: FDA "Sterile Processing Guide" (2004): Section IV.C.3 - emphasizes that diffusion flow testing must be performed under constant pressure. If the pressure drops by more than 10% of the initial value, the test conditions must be re-verified.

[0006] Additionally, if the upstream test pressure drops too quickly, it can cause the automatic filter integrity tester to sound a leak alarm, preventing the test from being completed. Summary of the Invention

[0007] The purpose of the embodiments of the present invention is to provide a method for solving the problem that when testing a large diffusion flow membrane filter with an automatic filter integrity tester, the gas pressure in the upstream volume drops too quickly during the test and the test cannot be successfully performed because the diffusion flow rate is too large and the upstream volume of the large diffusion flow membrane filter is too small.

[0008] In order to achieve the above objectives, the embodiment of the present invention designs a large diffusion flow membrane filter integrity test device, comprising:

[0009] air intake;

[0010] an automatic filter integrity tester, connecting the air inlet to the air inlet of the automatic filter integrity tester;

[0011] a buffer tank, connecting the air outlet of the automatic filter integrity tester to the air inlet of the buffer tank;

[0012] Membrane filter, connecting the gas outlet of the buffer tank to the feed liquid inlet of the membrane filter;

[0013] A feed liquid outlet is provided on the other side of the membrane filter; when the automatic filter integrity tester performs integrity testing on the membrane filter, the buffer tank stabilizes the pressure and provides buffering for the testing process.

[0014] Furthermore, in the large diffusion flow membrane filter integrity testing device of the present invention, the filtrate outlet of the membrane filter is open.

[0015] Furthermore, in the large diffusion flow membrane filter integrity testing device of the present invention, when gas is introduced into the buffer tank and the membrane filter, the buffer tank performs pressure stabilization and buffering.

[0016] Furthermore, in the large diffusion flow membrane filter integrity test device of the present invention, the automatic filter integrity tester further comprises:

[0017] a first sensor connected to the air inlet;

[0018] a proportional regulating valve, connected to one end of the proportional regulating valve at the air inlet;

[0019] a first solenoid valve, one end of which is connected to the other end of the proportional control valve;

[0020] an internal reference tank, the other end of the first solenoid valve being connected to an inlet of the internal reference tank;

[0021] The outlet of the internal reference tank is respectively connected to the inlets of the second sensor, the second solenoid valve and the third solenoid valve;

[0022] The outlet of the second solenoid valve is connected to the air inlet of the buffer tank;

[0023] The outlet of the third solenoid valve is emptied.

[0024] Furthermore, in the large diffusion flow membrane filter integrity testing device of the present invention, the membrane filter is composed of several stacked membrane packages.

[0025] The testing method of the large diffusion flow membrane filter integrity testing device in the present invention comprises the following steps:

[0026] Step S10: Connect the air inlet of the automatic filter integrity tester to a compressed air source and adjust the pressure to 0.6 MPa; connect a thin tube to the downstream end of the membrane filter, and place the other end of the thin tube in a water container to collect downstream diffusion flow bubbles during testing;

[0027] Enter step S20:

[0028] Step S20: During the test, the inlet of the buffer tank is connected to the automatic filter integrity tester, and the outlet is connected to the membrane filter; then the process proceeds to step S30;

[0029] Step S30: Selecting the diffusion flow test function of the automatic filter integrity tester, the automatic filter integrity tester first tests the upstream volume of the membrane filter integrity test device, and then proceeding to step S40;

[0030] Step S40: The automatic filter integrity tester controls the proportional regulating valve to enter the pressure boosting and stabilizing phase. After the stabilizing time is completed, the process proceeds to step S50.

[0031] Step S50: When the automatic filter integrity tester enters the diffusion flow test phase, an inverted graduated cylinder filled with water is used to collect the bubble flow rate downstream of the membrane filter, and the time is measured, and then the bubble flow rate collected per minute is calculated; after the test is completed, the automatic filter integrity tester automatically stops and displays the test result of the automatic filter integrity tester; and then the process proceeds to step S60;

[0032] Step S60: Record and analyze the test results: fill the test results of the automatic filter integrity tester and the value of the bubbles collected by the measuring cylinder into Table 1, and calculate the error.

[0033] Furthermore, in the testing method for the large diffusion flow membrane filter integrity test device described in this embodiment, the pressure boosting stage involves inflating the membrane filter to boost pressure to the test pressure value, then maintaining the pressure steady. The boost pressure is controlled by an electronic automatic proportional control valve. The air intake speed of the proportional control valve is constrained by the valve body aperture. As the volume increases, the time required to boost the test pressure increases. Therefore, a volume determination subroutine has been added to automatically extend the boost time based on the upstream volume until the set pressure is reached.

[0034] The pressure stabilization stage: After the pressure of the membrane filter reaches the test pressure, the pressure is maintained for about 5 minutes to allow the wet filter membrane micropores to establish a stable diffusion effect and achieve a stable diffusion flow;

[0035] The test phase: When entering the test phase, the upstream of the membrane filter is immediately isolated from the gas source, isolating a certain volume of gas upstream. As the gas molecules diffuse to the downstream of the filter, the gas pressure in the upstream volume will drop.

[0036] Furthermore, in the test method of the large diffusion flow membrane filter integrity test device described in this embodiment, the pressure stabilization time during the test is increased to 2 minutes in the pressure stabilization stage; and the time for testing the diffusion flow is shortened to 1-2 minutes.

[0037] Compared with the prior art, the embodiment of the present invention connects the air inlet to the air inlet of the automatic filter integrity tester; the air outlet of the automatic filter integrity tester is connected to the air inlet of the buffer tank; the air outlet of the buffer tank is connected to the feed liquid inlet of the membrane filter; when the automatic filter integrity tester performs integrity testing on the convection membrane filter, the buffer tank stabilizes the pressure and buffers the test process.

[0038] The embodiments of the present invention solve the problem of integrity test failure of large diffusion flow membrane filter: by externally connecting a buffer tank with suitable volume and optimizing the test procedure, the possibility of failure is avoided when performing integrity testing on "such filters" using an automatic filter integrity tester.

[0039] The embodiment of the present invention improves the test accuracy: by connecting an external buffer tank of suitable volume and optimizing the test procedure, the pressure drop during the test is controlled within a limited range (within 10%), ensuring the accuracy and reliability of the test results.

[0040] The embodiments of the present invention are low-cost and easy to operate: the buffer tank has a low manufacturing cost; software upgrades are easy to implement, and testing costs are reduced.

[0041] The test results of the embodiment of the present invention are electronically recorded: the large diffusion flow membrane filter can be integrity tested using an automatic filter integrity tester, and the test results are electronically recorded, which meets the data integrity requirements of industries such as biomedicine.

[0042] This solves the problem that when using an automatic filter integrity tester to test "this type of filter", the gas pressure in the upstream volume drops too quickly during the test and the test cannot be successfully performed due to the excessive diffusion flow and the small upstream volume of "this type of filter". BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the connection of the buffer tank in the integrity test of the present invention;

[0044] Figure 2 This is a test process diagram;

[0045] Figure 3 This is a schematic diagram of test results of the first embodiment of the present invention;

[0046] Figure 4 Schematic diagram of test results of the second embodiment of the present invention. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the present invention more apparent, various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in various embodiments of the present invention to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the claims of this application can be implemented.

[0048] The first embodiment of the present invention relates to a large diffusion flow membrane filter integrity test device, such as Figure 1-Figure 2 Shown, including:

[0049] In this embodiment, an air inlet 1 is provided on the large diffusion flow membrane filter device;

[0050] Automatic filter integrity tester 2, connecting the air inlet 1 to the air inlet of the automatic filter integrity tester 2;

[0051] Buffer tank 3, connecting the air outlet of the automatic filter integrity tester 2 to the air inlet of the buffer tank 3;

[0052] Membrane filter 4, connect the gas outlet of buffer tank 3 to the feed liquid inlet of membrane filter 4;

[0053] A liquid outlet is provided on the other side of the membrane filter 4; when the automatic filter integrity tester 2 performs integrity testing on the membrane filter 4, the buffer tank 3 stabilizes and buffers the test process.

[0054] This embodiment solves the problem of failure in integrity testing of large diffusion membrane filter: by connecting an external buffer tank with suitable volume and optimizing the test procedure, the possibility of failure is avoided when performing integrity testing on large diffusion membrane filter using an automatic filter integrity tester; the test accuracy is improved: by connecting an external buffer tank with suitable volume and optimizing the test procedure, the air pressure drop during the test is controlled within a limited range (within 10%), ensuring the accuracy and reliability of the test results; this embodiment has low cost and simple operation: the buffer tank has low manufacturing cost; software upgrade is easy to implement, which reduces the testing cost.

[0055] In order to achieve the above technical effects, the large diffusion flow membrane filter integrity test device in this embodiment is as follows: Figure 1-Figure 2 As shown, the filtrate outlet of the membrane filter 4 is open, which facilitates the outflow of the filtrate and reduces the outflow resistance.

[0056] In order to achieve the above technical effects, the large diffusion flow membrane filter integrity test device in this embodiment is as follows: Figure 1-Figure 2 As shown, when gas is introduced into the buffer tank 3 and the membrane filter 4, the buffer tank performs pressure stabilization and buffering.

[0057] In order to achieve the above technical effects, the large diffusion flow membrane filter device in this embodiment, such as Figure 1-Figure 2 As shown, the automatic filter integrity tester 2 further includes:

[0058] The first sensor 21 is connected to the air inlet 1; the first sensor 21 is used to measure the inlet pressure and convert it into a pressure value for reading.

[0059] The air inlet 1 is simultaneously connected to one end of a proportional regulating valve 22 ; the proportional regulating valve 22 is used to control the pressure of the system.

[0060] The other end of the proportional control valve 22 is connected to one end of a first electromagnetic valve 23 ; the first electromagnetic valve 23 is used to perform on-off control of the system.

[0061] The other end of the first solenoid valve 23 is connected to the inlet of an internal reference tank 24. The internal reference tank 24 is used for calibration and reference. It contains a standard substance of known concentration, which can be used to compare test sample results to ensure data accuracy. This helps eliminate errors and environmental interference in the automatic filter integrity tester 2.

[0062] The outlet of the internal reference tank 24 is connected to the inlets of the second sensor 25, the second solenoid valve 26 and the third solenoid valve 27 respectively;

[0063] The outlet of the second solenoid valve 26 is connected to the air inlet of the buffer tank 3;

[0064] The outlet of the third solenoid valve 27 is exhausted.

[0065] In order to achieve the above technical effects, the large diffusion flow membrane filter integrity test device in this embodiment is as follows: Figure 1-Figure 2 As shown, the membrane filter 4 is composed of several membrane packages stacked together.

[0066] In order to achieve the above technical effects, the second embodiment of the present invention further provides a testing method for a large diffusion flow membrane filter integrity testing device, such as Figures 1-4 As shown, including the following steps:

[0067] Step S10: Connect the air inlet of the automatic filter integrity tester to a compressed air source and adjust the pressure to 0.6 MPa; connect a thin tube to the downstream end of the membrane filter 4, and place the other end of the thin tube in a water container to collect downstream diffusion flow bubbles during testing;

[0068] Enter step S20:

[0069] Step S20: During the test, the inlet of the buffer tank 3 is connected to the automatic filter integrity tester, and the outlet is connected to the membrane filter 4; then the process proceeds to step S30;

[0070] Step S30: Selecting the diffusion flow test function of the automatic filter integrity tester 2, the automatic filter integrity tester 2 first tests the upstream volume of the membrane filter integrity test device, and then proceeds to step S40; Step S40: The automatic filter integrity tester 2 controls the electronic proportional pressure regulating valve to enter the pressure boosting and stabilizing phase. After the pressure stabilizing period is completed, proceeds to step S50;

[0071] Step S50: When the automatic filter integrity tester 2 enters the diffusion flow test phase, an inverted graduated cylinder filled with water is used to collect the bubble flow rate downstream of the membrane filter 4, and the time is measured, and then the bubble flow rate collected per minute is calculated. After the test is completed, the automatic filter integrity tester 2 automatically stops and displays the test result of the automatic filter integrity tester 2. Then, the process proceeds to step S60.

[0072] Step S60: Record and analyze the test results: fill the test results of the automatic filter integrity tester 2 and the value of the bubbles collected by the measuring cylinder into Table 1, and calculate the error.

[0073] In a second embodiment of the present invention, a method for testing the integrity of a large diffusion membrane filter is provided, such as Figures 1-4As shown, during the pressure-boosting phase, the membrane filter 4 is inflated and pressurized to the test pressure value, then maintained at a constant pressure. The pressure boost is controlled by the proportional control valve 22. The air intake speed of the proportional control valve 22 is constrained by the valve body aperture. As the volume increases, the time required to boost the test pressure increases. Therefore, a volume determination subroutine has been added to automatically extend the boost time based on the upstream volume until the set pressure is reached.

[0074] Pressure stabilization stage: After the pressure of the membrane filter 4 rises to the test pressure, the pressure is maintained for about 5 minutes to allow the wet filter membrane micropores to establish a stable diffusion effect and achieve a stable diffusion flow;

[0075] Testing phase: When entering the testing phase, the upstream of the membrane filter 4 is immediately isolated from the gas source, isolating a certain volume of gas upstream. As the gas molecules diffuse to the downstream of the filter, the gas pressure in the upstream volume will drop.

[0076] In a second embodiment of the present invention, a method for testing the integrity of a large diffusion membrane filter is provided, such as Figures 1-4 As shown, the stabilization time during the pressure stabilization stage is increased to 2 minutes; the time for testing the diffusion flow is reduced to 1-2 minutes.

[0077] The present invention electronically records test results, enabling integrity testing of large diffusion membrane filters using an automated filter integrity tester. This electronic recording of test results meets the data integrity requirements of industries such as biomedicine. This solves the current problem of using automated filter integrity testers to test such filters, where the excessive diffusion flow rate and the relatively small upstream volume of the large diffusion membrane filter cause the gas pressure in the upstream volume to drop too quickly during testing, preventing successful testing.

[0078] In order to better illustrate the technical effect of the second embodiment of the present invention, a third embodiment and a fourth embodiment are provided:

[0079] Example 3: Test a large diffusion flow membrane package of a certain brand, with a membrane package area of ​​2.5 square meters, a test pressure of 0.2 MPa, a diffusion flow standard value of 4000 ml / min, a buffer tank 3 with a volume of 25000 ml, a pressure stabilization time of 7 minutes, and a test time of 2 minutes. Figure 3 、 4 As shown, the test results are shown in No. 1 in Table 1.

[0080] Fourth embodiment: Two large diffusion flow membrane packages of a certain brand were tested, with a membrane package area of ​​5 square meters, a test pressure of 0.2 MPa, a diffusion flow standard value of 8000 ml / min, a buffer tank 3 with a volume of 50,000 ml, a pressure stabilization time of 7 minutes, and a test time of 2 minutes. The test results are shown in No. 2 in the table.

[0081]

[0082] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A large diffusion flow membrane filter integrity test device, characterized in that: include: air intake; an automatic filter integrity tester, connecting the air inlet to the air inlet of the automatic filter integrity tester; a buffer tank, connecting the air outlet of the automatic filter integrity tester to the air inlet of the buffer tank; Membrane filter, connecting the gas outlet of the buffer tank to the feed liquid inlet of the membrane filter; A feed liquid outlet is provided on the other side of the membrane filter; when the automatic filter integrity tester performs integrity testing on the membrane filter, the buffer tank stabilizes the pressure and provides buffering for the testing process.

2. The large diffusion flow membrane filter integrity testing device according to claim 1, characterized in that: The filtrate outlet of the membrane filter is open.

3. The large diffusion flow membrane filter integrity testing device according to claim 1, characterized in that: When gas is introduced into the buffer tank and the membrane filter, the buffer tank performs pressure stabilization and buffering.

4. The large diffusion flow membrane filter integrity testing device according to claim 1, characterized in that: The automatic filter integrity tester further comprises: a first sensor connected to the air inlet; a proportional regulating valve, connected to one end of the proportional regulating valve at the air inlet; a first solenoid valve, one end of which is connected to the other end of the proportional control valve; an internal reference tank, the other end of the first solenoid valve being connected to an inlet of the internal reference tank; The outlet of the internal reference tank is respectively connected to the inlets of the second sensor, the second solenoid valve and the third solenoid valve; The outlet of the second solenoid valve is connected to the air inlet of the buffer tank; The outlet of the third solenoid valve is emptied.

5. The large diffusion flow membrane filter integrity testing device according to claim 1, characterized in that: The membrane filter is formed by stacking several membrane packages.

6. The testing method of the large diffusion flow membrane filter integrity testing device according to any one of claims 1 to 5, characterized in that: Including the following steps: Step S10, the air inlet of the automatic filter integrity tester is connected to a compressed air source, and the pressure is adjusted to 0.6 MPa; Connect a thin tube to the downstream end of the membrane filter and place the other end of the thin tube into a water container to collect the downstream diffusion flow bubbles during testing; Enter step S20: Step S20: During the test, the inlet of the buffer tank is connected to the automatic filter integrity tester, and the outlet is connected to the membrane filter; then the process proceeds to step S30; Step S30: Selecting the diffusion flow test function of the automatic filter integrity tester, the automatic filter integrity tester first tests the upstream volume of the membrane filter integrity test device, and then proceeds to step S40; Step S40: The automatic filter integrity tester controls the proportional regulating valve to enter the pressure boosting and stabilizing phase. After the stabilizing time is completed, the process proceeds to step S50. Step S50: When the automatic filter integrity tester enters the diffusion flow test phase, an inverted graduated cylinder filled with water is used to collect the bubble flow rate downstream of the membrane filter, and the time is measured, and then the bubble flow rate collected per minute is calculated; after the test is completed, the automatic filter integrity tester automatically stops and displays the test result of the automatic filter integrity tester; Go to step S60; Step S60: Record and analyze the test results: fill the test results of the automatic filter integrity tester and the value of the bubbles collected by the measuring cylinder into Table 1, and calculate the error.

7. The testing method of the large diffusion flow membrane filter integrity testing device according to claim 6, characterized in that: The boost phase involves inflating the membrane filter to boost the pressure to the test pressure, then maintaining the pressure steady. The boost pressure is controlled by an electronic automatic proportional control valve. The air intake speed of the proportional control valve is constrained by the valve body aperture. As the volume increases, the time required to boost the test pressure increases. A volume determination subroutine has been added to automatically extend the boost time based on the upstream volume until the set pressure is reached. The pressure stabilization stage: After the pressure of the membrane filter reaches the test pressure, the pressure is maintained for about 5 minutes to allow the wet filter membrane micropores to establish a stable diffusion effect and achieve a stable diffusion flow; The test phase: When entering the test phase, the upstream of the membrane filter is immediately isolated from the gas source, isolating a certain volume of gas upstream. As the gas molecules diffuse to the downstream of the filter, the gas pressure in the upstream volume will drop.

8. The testing method of the large diffusion flow membrane filter integrity testing device according to claim 6, characterized in that: In the pressure stabilization stage, the pressure stabilization time during the test is increased to 2 minutes; and the time for testing the diffusion flow rate is reduced to 1-2 minutes.

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