A reverse osmosis membrane strength testing device and a testing method thereof

Abstract

The present invention discloses a reverse osmosis membrane strength testing device and a testing method thereof, and relates to the technical field of reverse osmosis membrane testing. The reverse osmosis membrane strength testing device comprises: a reverse osmosis membrane evaluation tank, the reverse osmosis membrane evaluation tank comprises a tank body, a reverse osmosis membrane is placed in the tank body, the reverse osmosis membrane divides the tank body into a test solution chamber and a permeate chamber; a test solution water tank, the test solution water tank is used to store and provide the test solution required by the test solution chamber, the test solution chamber and the permeate chamber are both provided with a pipeline for connecting the test solution water tank; a booster pump, the booster pump is provided in the pipeline connecting the test solution water tank and the test solution chamber. The reverse osmosis membrane strength testing device and the testing method thereof directly obtain the reverse osmosis membrane strength by testing the desalination rate and water flux of the reverse osmosis membrane, so that the strength of the reverse osmosis membrane can be accurately known.

Description

Technical Field

[0001] The invention relates to the technical field of reverse osmosis membrane testing, in particular to a reverse osmosis membrane strength testing device and a testing method thereof. Background Art

[0002] Reverse osmosis membrane is an artificial semipermeable membrane with certain characteristics made by simulating biological semipermeable membrane. It is the core component of reverse osmosis technology. The principle of reverse osmosis technology is to separate these substances and water under the action of higher osmotic pressure than the solution, based on the fact that other substances cannot pass through the semipermeable membrane. The pore size of the reverse osmosis membrane is very small, so it can effectively remove dissolved salts, colloids, microorganisms, organic matter, etc. in water. The system has the advantages of good water quality, low energy consumption, no pollution, simple process and easy operation.

[0003] Permeability, water flux and compressive strength are important indicators to measure the performance of reverse osmosis membranes. However, due to the risk of clogging of the micropores of the reverse osmosis membrane during the filtration process, it is difficult for the reverse osmosis membrane to maintain its high efficiency for a long time.

[0004] Similarly, the patent with publication number CN118079659A proposes a comprehensive detection device for ultrafiltration membrane based on permeability and strength, which can form an ultrafiltration system through the filter housing and the filter components inside it. The ultrafiltration membrane can filter macromolecular particles, thereby purifying water. By detecting the drainage rate of the ultrafiltration system under the premise of constant water supply pressure, the water permeability can be measured; and under the condition of continuously increasing water supply pressure, the moment when the drainage rate suddenly surges can reflect the upper limit of the strength of the permeable membrane. However, relying only on the permeability to detect the strength of the membrane leads to insufficient detection accuracy, and the detection accuracy needs to be improved. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a reverse osmosis membrane strength testing device and a testing method thereof, which solves the problem in the prior art that the detection accuracy needs to be improved.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a reverse osmosis membrane strength testing device, comprising: a reverse osmosis membrane evaluation tank, the reverse osmosis membrane evaluation tank comprising a tank body, the tank body containing a reverse osmosis membrane, the reverse osmosis membrane dividing the tank body into a test solution chamber and a permeate solution chamber; a test solution water tank, the test solution water tank is used to store and provide the test solution required by the test solution chamber, the test solution chamber and the permeate solution chamber are both provided with a pipeline for connecting the test solution water tank; a booster pump, the booster pump is arranged on the pipeline connecting the test solution water tank and the test solution chamber, and the booster pump is used to pressurize the test solution entering the test solution chamber; the desalination rate and water flux of the permeate and the test solution before and after the booster pump works are detected to characterize the strength of the reverse osmosis membrane.

[0007] Furthermore, a double clamping structure is provided in the cell body, and the double clamping structure is composed of two groups of single clamping structures, and the two groups of single clamping structures are distributed on both sides of the reverse osmosis membrane; the single clamping structure includes a point pressure head, and at least two of the point pressure heads are provided, and the point pressure heads are in point-to-face contact with the reverse osmosis membrane, and a hollow bracket is provided on the side of the point pressure head away from the reverse osmosis membrane; the point pressure heads of the two groups of single clamping structures are positioned opposite to each other, so that the two groups of point pressure heads clamp the reverse osmosis membrane point-to-point, thereby reducing the coverage area of ​​the reverse osmosis membrane.

[0008] Furthermore, the clamping structure also includes: a gap lifting rod, which is located between the point pressure head and the hollow bracket so that there is a gap between the point pressure head and the hollow bracket; a porous plate, which is located on the side of the hollow bracket close to the reverse osmosis membrane, and the porous plate is nested in one end of the gap lifting rod close to the point pressure head, and an elastic member is provided between the porous plate and the hollow bracket, and the porous plate does not contact the reverse osmosis membrane in a natural state of the elastic member; the hollowing degree of the porous plate in the permeable solution chamber is greater than the hollowing degree of the porous plate in the test solution chamber; an approach structure, which is located between the two groups of porous plates, and the approach structure is used to drive the two groups of porous plates to move relative to or towards each other; when the boost pump is pressurized, the hydraulic pressure in the test solution chamber increases instantaneously to push the porous plate in the test solution chamber to be pressed against the filtration surface of the reverse osmosis membrane, and the porous plate in the test solution chamber pushes another group of porous plates to be pressed against the filtration back side of the reverse osmosis membrane through the approach structure, so that the two groups of porous plates clamp the reverse osmosis membrane during instantaneous pressurization.

[0009] Furthermore, shut-off valves and pressure gauges are provided on the pipelines between the booster pump and the test solution chamber, on the pipelines between the permeable solution chamber and the test solution water tank, and on the pipelines between the test solution chamber and the test solution water tank; flow meters are provided on the pipelines between the test solution chamber and the test solution water tank, and the flow meters are used to detect the liquid flow passing through the pipelines.

[0010] On the other hand, the present invention also provides a reverse osmosis membrane strength testing method, comprising the following steps:

[0011] S1. Take a reverse osmosis membrane sample and soak it in deionized water or distilled water for later use;

[0012] S2. Prepare a NaCl water solution of corresponding concentration according to the type of reverse osmosis membrane as a test solution and adjust the pH to 7.5 with hydrochloric acid or sodium hydroxide for later use;

[0013] S3. Open the stop valve, adjust the booster pump, adjust the operating pressure according to the type of membrane, and after the required operating time, collect a certain amount of test solution in a beaker, measure the volume of the permeate in a certain period of time with a stopwatch and a measuring cylinder, and measure the conductivity of the test solution and the permeate respectively, or measure the total dissolved solids content of the test solution and the permeate respectively;

[0014] S4, calculating the desalination rate and water flux of the reverse osmosis membrane sample according to the measurement result of S3, and calculating the initial average desalination rate according to the desalination rate, and calculating the initial average water flux according to the water flux, to obtain the initial average desalination rate and the initial average water flux;

[0015] S5. Adjust the operating pressure to 1.5 times the test pressure and run it for the required time, then adjust the stop valve to adjust the operating pressure to the normal test pressure, and calculate the average salt rejection rate and average water flux of the reverse osmosis membrane sample after high pressure according to the calculation method in S4;

[0016] S6, calculating the desalination rate change rate and the water flux change rate according to the initial average desalination rate and the initial average water flux in S4 and the average desalination rate after high pressure and the average water flux after high pressure in S5;

[0017] S7. The compressive strength of the reverse osmosis membrane is obtained by the change rate of the desalination rate and the change rate of the water flux.

[0018] Furthermore, the method for calculating the desalination rate of the reverse osmosis membrane sample in S4 by conductivity is: ) x 100%, where R is the desalination rate, k p is the conductivity of the permeate, k f To test the solution conductivity;

[0019] The method for calculating the initial average desalination rate in S4 is: n, where R2 is the initial average desalination rate of the sample, R is the desalination rate of the i-th sample in the sample, and n is the total number of samples in the sample.

[0020] Further, the method for calculating the desalination rate by the total dissolved solid content in S4 is: ) x 100%, where R is the desalination rate, C P is the total dissolved solid content of the permeate, C f To test the total soluble solid content of the solution;

[0021] The method for calculating the initial average desalination rate in S4 is: n, where R2 is the initial average desalination rate of the sample, R is the desalination rate of the i-th sample in the sample, and n is the total number of samples in the sample.

[0022] Further, the method for calculating the water permeability of the reverse osmosis membrane sample in S4 is: , where F is the water flux, v is the volume of permeate collected in time t; a is the effective membrane area, and t is the time taken to collect v volume of permeate;

[0023] The method for calculating the initial average water flux of the reverse osmosis membrane sample in S4 is: n, where F2 is the initial average water flux, F i is the water flux of the i-th reverse osmosis membrane sample, and n is the total number of reverse osmosis membrane samples tested in the sample.

[0024] Further, the average salt rejection rate and the average water flux after high pressure of the reverse osmosis membrane sample calculated in S5 by the calculation method of S4 are R3 and F3 respectively;

[0025] The calculation method of the change rate of desalination rate in S6 is △R=( - ) / ×100%, where △R is the change rate of desalination rate, R3 is the average desalination rate of the sample after high pressure, and R2 is the initial average desalination rate;

[0026] The calculation method of the water flux change rate in S6 is △F=( - ) / ×100%, where △F is the water flux change rate of the sample; F2 is the initial average water flux of the sample, and F3 is the average water flux of the sample after high-pressure operation.

[0027] Furthermore, the reverse osmosis membrane strength is calculated by the water flux change rate and the desalination rate change rate as follows: ,in is the strength of the reverse osmosis membrane, is the influence weight of the change rate of desalination rate, is the influence weight of the water flux change rate.

[0028] The present invention has the following beneficial effects:

[0029] (1) Through the reverse osmosis membrane strength testing device and the testing method thereof, the strength of the reverse osmosis membrane can be directly obtained by testing the desalination rate and water flux of the reverse osmosis membrane. That is, the greater the change rate of water flux and the change rate of desalination rate, the smaller the strength of the reverse osmosis membrane. Conversely, when the change rate of water flux and the change rate of desalination rate are smaller, the strength of the reverse osmosis membrane is greater, thereby being able to accurately know the strength of the reverse osmosis membrane.

[0030] (2) The reverse osmosis membrane strength testing device and the testing method thereof, the mechanism for clamping the reverse osmosis membrane in the reverse osmosis membrane evaluation pool is a point-to-point clamping structure, thereby reducing the coverage area of ​​the clamping structure on the reverse osmosis membrane and increasing the effective filtration area of ​​the reverse osmosis membrane. The larger the effective filtration area, the greater the change in the measured desalination rate and water flux, thereby improving the accuracy of the test results.

[0031] (3) The reverse osmosis membrane strength testing device and the testing method thereof are provided with a porous plate connected by an elastic member. When the elastic member is in a natural state, the porous plate does not contact the reverse osmosis membrane, that is, under a stable pressure state, the elastic member is in a natural state, so the porous plate does not contact the reverse osmosis membrane. However, when the booster pump increases the pressure, the hydraulic pressure in the test solution chamber increases instantaneously, so that the liquid pressure can push the non-porous area of ​​the porous plate in the test solution chamber, so that the porous plate in the test solution chamber is pressed against the filter surface of the reverse osmosis membrane, thereby improving the stability of the reverse osmosis membrane under an instantaneous pressurized state.

[0032] (4) The reverse osmosis membrane strength testing device and the testing method thereof are provided with an approach structure, which is used to drive the two groups of porous plates to move relative to or toward each other, so that the porous plates in the test solution chamber push the other group of porous plates to be pressed against the filtering back side of the reverse osmosis membrane through the approach structure, so that the two groups of porous plates clamp the reverse osmosis membrane during instantaneous pressure increase to maintain the stability of the reverse osmosis membrane.

[0033] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of the present invention;

[0035] Figure 2 A cutaway diagram of a reverse osmosis membrane evaluation pool of the present invention;

[0036] Figure 3 It is a schematic diagram of the internal structure of the reverse osmosis membrane evaluation pool of the present invention;

[0037] Figure 4 For the present invention Figure 3 A magnified image of area A;

[0038] Figure 5 For the present invention Figure 3 A magnified view of area B;

[0039] Figure 6 A three-dimensional diagram of a first approach structure of the present invention;

[0040] Figure 7 For the present invention Figure 2 Exploded diagram of

[0041] Figure 8It is a structural schematic diagram of the pressed plate of the present invention;

[0042] Fig. 9 This is a connection diagram of the upper porous plate and the hollow support of the present invention;

[0043] Fig.10 For the present invention Fig. 9 Exploded diagram of

[0044] Fig.11 For the present invention Fig.10 Another perspective of the picture;

[0045] Fig.12 This is a connection diagram of the lower porous plate and the hollow support of the present invention;

[0046] Fig.13 For the present invention Fig.12 Exploded diagram of

[0047] Fig.14 For the present invention Fig.13 Another perspective of the picture;

[0048] Fig.15 This is a schematic diagram of the installation of the first approach structure of the present invention;

[0049] Fig.16 A state diagram of closing two porous plates for the first approach structure of the present invention;

[0050] Fig.17 It is a front view installation diagram of the second approach structure of the present invention;

[0051] Fig.18 is a perspective view of a second approach structure of the present invention;

[0052] Fig.19 For the present invention Figure 7 Magnified image of area C;

[0053] Fig. 20 For the present invention Fig.11 A magnified view of region D;

[0054] Fig.21 For the present invention Fig.12 A magnified view of region E;

[0055] Fig. 22 For the present invention Fig.13 A magnified view of region F;

[0056] Fig.23 For the present invention Fig.14 Magnified view of area G.

[0057] In the figure, 1. test solution water tank; 2. booster pump; 4. pressure gauge; 5. reverse osmosis membrane; 6. reverse osmosis membrane evaluation pool; 610. pool body; 611. test solution inlet; 612. permeate outlet; 613. sealing ring; 620. pressing plate; 630. hollow bracket; 640. lifting gap rod; 641. point pressure head; 650. approach structure; 651. column; 652. swing arm; 653. pulling arm; 654. hinged seat; 655. fixed seat; 656. rack plate; 657. gear; 660. test solution chamber; 670. pulling rod; 680. porous plate; 690. elastic member; 9. stop valve; 10. flow meter; 11. heater; 12. temperature monitor; 13. measuring cylinder. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0060] Below through Figure 1 - Fig.23 The invention describes a reverse osmosis membrane strength testing device and a testing method provided by an embodiment of the invention.

[0061] See also Figure 1 An embodiment of the present invention provides a reverse osmosis membrane strength testing device, including a reverse osmosis membrane evaluation pool 6 and a test solution water tank 1. The reverse osmosis membrane evaluation pool 6 includes a pool body 610 as a reverse osmosis membrane testing site, and the test solution water tank 1 stores and provides the required test solution.

[0062] In order to test the reverse osmosis membrane 5, the reverse osmosis membrane 5 to be tested is placed in the cell body 610. The reverse osmosis membrane 5 divides the cell body 610 into a test solution chamber 660 and a permeate solution chamber. The test solution chamber 660 is close to the incoming liquid direction. The liquid that passes through the reverse osmosis membrane 5 and enters the permeate solution chamber is the permeate liquid. In this state, the permeate liquid and the test solution desalination rate and water flux in the test solution tank 1 are tested.

[0063] A test solution inlet 611 is provided on one side of the cell body 610 close to the test solution chamber 660 , and a permeate outlet 612 is provided on one side of the cell body 610 close to the through liquid chamber.

[0064] In order to provide another set of test data for comparison with the desalination rate and water flux of the permeate and the test solution in the above state, so as to obtain the strength of the reverse osmosis membrane 5, a booster pump 2 is provided here. The booster pump 2 is located on the pipeline connecting the test solution tank 1 and the test solution chamber 660, and the booster pump 2 is used to pressurize the test solution entering the test solution chamber 660. When the booster pump 2 increases the pressure, the pressure in the test solution chamber 660 increases. In this state, the desalination rate and water flux of the permeate and the test solution in the test solution tank 1 are tested again.

[0065] By comparing the two desalination rates and water fluxes and calculating them, the strength of the reverse osmosis membrane can be obtained.

[0066] Therefore, the reverse osmosis membrane strength testing device provided in the embodiment of the present invention can directly obtain the reverse osmosis membrane strength by testing the salt rejection rate and water flux of the reverse osmosis membrane, so that the strength of the reverse osmosis membrane can be accurately known.

[0067] Preferably, in order to conveniently obtain the permeate, a branch pipeline is provided on the pipeline between the permeate and the test solution tank 1, and a measuring cylinder 13 is directly assembled on the branch pipeline, so that the permeate can be conveniently obtained, providing convenience for detection.

[0068] In addition, it is worth mentioning that a valve is also installed on this branch pipeline to control the flow direction of the permeate so that it flows to the desired position.

[0069] Preferably, the test solution water tank 1 is equipped with a heater 11 and a temperature monitor 12 to maintain a constant temperature in the system.

[0070] Combination Figure 2 - Fig.14As shown, during the test, the existing test device uses a perforated plate to directly press the reverse osmosis membrane, thereby fixing the position of the reverse osmosis membrane. Although the hole area of ​​the perforated plate can pass the solution, the non-hole area cannot pass the solution, resulting in the reverse osmosis membrane covered by the non-hole area failing to play a filtering role, thereby reducing the filtration area of ​​the reverse osmosis membrane. In order to solve this problem, a double clamping structure is provided in the cell body 610, and the double clamping structure is composed of two groups of single clamping structures, and the two groups of single clamping structures are distributed on both sides of the reverse osmosis membrane 5; the single clamping structure includes a point pressure head 641, and the point pressure head 641 is provided with at least two, and the point pressure head 641 is in point-to-face contact with the reverse osmosis membrane 5, and the two groups of point pressure heads 641 of the single clamping structure are relative to each other, so that the two groups of point pressure heads 641 point-to-point clamp the reverse osmosis membrane 5, and the point-to-point contact can minimize the area covered by the reverse osmosis membrane 5, thereby increasing its filtration area, and on the basis of improving the accuracy of the detection, it can also maintain the stability of the reverse osmosis membrane 5 during operation. In order to fix the point pressure head 641, a hollow bracket 630 is provided on the side of the point pressure head 641 away from the reverse osmosis membrane 5, and the hollow bracket 630 is in a hollow state, so that the bracket here can avoid blocking the flow of solution.

[0071] Preferably, a pressing plate 620 is arranged on the side of the hollow bracket 630 away from the reverse osmosis membrane 5. The upper pressing plate 620 can prevent the permeate from overflowing, and the lower pressing plate 620 plays a supporting and bearing role. The lower pressing plate 620 should be an annular structure, and the two pressing plates 620 should be connected by a threaded pull rod 670.

[0072] Optionally, the point pressure head 641 can be spherical, hemispherical or conical. When the point pressure head 641 is conical, the end thereof pressing on the reverse osmosis membrane 5 should be ground and polished to form a curved surface structure to avoid puncturing the reverse osmosis membrane. In summary, the shape of the point pressure head 641 can be any style, as long as the contact mode between the point pressure head 641 and the reverse osmosis membrane 5 is point contact.

[0073] During the later operation, it is necessary to increase the pressure of the solution in the system to obtain the data after pressurization. Therefore, the solution will impact the reverse osmosis membrane at the moment of pressurization. Moreover, since the stabilizing ability of the point pressure head 641 on the reverse osmosis membrane is significantly lower than that of the perforated plate in the prior art, the probability of deformation of the reverse osmosis membrane increases. In order to solve this problem, the clamping structure mentioned above also includes a lifting rod 640 and a porous plate 680. The lifting rod 640 is located between the point pressure head 641 and the hollow bracket 630 to ensure that the point pressure head 641 is in contact with the hollow bracket 630. There is a gap between the brackets 630, and the gap is used to accommodate the porous plate 680, and the porous plate 680 is located on the side of the hollow bracket 630 close to the reverse osmosis membrane 5, and the porous plate 680 is nested in one end of the gap lifting rod 640 close to the point pressure head 641, and there is an elastic member 690 between the porous plate 680 and the hollow bracket 630. When the elastic member 690 is in a natural state, the porous plate 680 does not contact the reverse osmosis membrane 5, that is, in a stable pressure state, the elastic member 690 is in a natural state, so the porous plate 680 does not contact the reverse osmosis membrane 5.

[0074] When the boost pump 2 increases the pressure, the hydraulic pressure in the test solution chamber 660 increases instantaneously. This liquid pressure can push the non-porous area of ​​the porous plate 680 (the porous plate 680 of the lower layer) in the test solution chamber 660, so that the porous plate 680 in the test solution chamber 660 is pressed against the filtering surface of the reverse osmosis membrane 5, thereby improving the stability of the reverse osmosis membrane under the instantaneous pressurization state.

[0075] like Figure 20-23 As shown, preferably, the elastic member 690 is a spring.

[0076] Here, it is limited that the hollowing degree of the porous plate 680 in the permeable solution chamber is greater than the hollowing degree of the porous plate 680 in the test solution chamber 660. The reason for this setting is to increase the liquid permeability of the upper porous plate 680 under the pressurized state, to avoid the upper porous plate 680 from moving too much upward under the pressurized state, and to further improve the stability of the reverse osmosis membrane 5 under the pressurized state.

[0077] The present application also provides an approach structure 650, which is located between the two groups of porous plates 680, and is used to drive the two groups of porous plates 680 to move relative to or toward each other, so that the porous plates 680 in the test solution chamber 660 push the other group of porous plates 680 to be pressed onto the filtering back side of the reverse osmosis membrane 5 through the approach structure 650, so that the two groups of porous plates 680 clamp the reverse osmosis membrane 5 during instantaneous pressurization.

[0078] like Figure 7 - Fig.14 as well as Figure 19-Figure 23In addition, the hollowing degree of the upper porous plate 680 is greater than that of the lower porous plate 680. The upper porous plate 680 can be made of a hollow steel wire mesh, and the lower porous plate 680 is a plate body with through holes. This solution can effectively avoid the situation where the water pressure acts on the upper porous plate 680 when the water pressure suddenly increases, causing the upper porous plate 680 to move upward and separate from the reverse osmosis membrane 5.

[0079] For example, the proximity structure 650 is Figure 4 , Figure 6 , Fig.15 and Fig.16 The structure shown is the first approach structure, which includes a column 651 fixed on the lower annular pressing plate 620, a rotary arm 652 rotatably mounted on the upper end of the column 651, and a pull arm 653 rotatably mounted on both ends of the rotary arm 652. The other end of the pull arm 653 is hinged to the corresponding porous plate 680 through a hinge seat 654. Before pressurization, Fig.15 There is a gap between the two-sided porous plates 680. When the pressure is increased instantly, the porous plate 680 at the bottom is subjected to water pressure, and the pull arm 653 pushes the rotary arm 652 to rotate, so that the pull arm 653 at the other end pulls the porous plate 680 at the top to press it onto the reverse osmosis membrane, forming Fig.16 Status shown.

[0080] Preferably, the access structures 650 are arranged in a circular array around the reverse osmosis membrane 5 .

[0081] For another example, the proximity structure 650 is a second proximity structure, such as Fig.17 and Fig.18 The structure shown includes a column 651 fixed on the lower annular pressing plate 620, a gear 657 is rotatably mounted on the upper end of the column 651, rack plates 656 are meshed on both sides of the gear 657, and the end of the rack plate 656 away from the gear 657 is fixed to the side of the porous plate 680 away from the reverse osmosis membrane 5 through a fixing seat 655. When pressurized, the lower porous plate 680 pushes the gear 657 to rotate through the lower rack plate 656, so that the gear 657 pulls the upper porous plate 680 through another rack plate 656 to press the reverse osmosis membrane 5.

[0082] Preferably, the access structures 650 are arranged in a circular array around the reverse osmosis membrane 5 .

[0083] like Figure 1 As shown, a stop valve 9 and a pressure gauge 4 are provided on the pipeline between the booster pump 2 and the test solution chamber 660, on the pipeline between the permeate solution chamber and the test solution water tank 1, and on the pipeline between the test solution chamber 660 and the test solution water tank 1. The stop valve 9 is used to open and close the corresponding pipeline, and the pressure gauge 4 is used to detect the pressure of the corresponding pipeline to keep the pressure of the system stable.

[0084] In addition, flow meters 10 are provided on the pipelines of the test solution chamber 660 and the test solution water tank 1 , and the flow meters 10 are used to detect the flow of liquid passing through the pipelines.

[0085] On the other hand, the present invention also provides a reverse osmosis membrane strength testing method, comprising the following steps:

[0086] S1. Take a reverse osmosis membrane sample and soak it in deionized water or distilled water for later use;

[0087] Preferably, the shape of the reverse osmosis membrane sample can be square, circular or other shapes, and the sample should be free of obvious defects such as wrinkles and damage. The size of the reverse osmosis membrane sample should meet the requirement of completely covering the sealing ring 613 of the reverse osmosis membrane evaluation tank 6 to avoid leakage; and the effective membrane area in the reverse osmosis membrane evaluation tank 6 is not less than 2.5×10 -3 ㎡.

[0088] S2. Prepare a NaCl water solution of corresponding concentration according to the type of reverse osmosis membrane as a test solution and adjust the pH to 7.5 with hydrochloric acid or sodium hydroxide for later use;

[0089] In addition, the pH of hydrochloric acid or sodium hydroxide can fluctuate by 0.5 on the basis of 7.5, that is, the pH of hydrochloric acid or sodium hydroxide can be selected to be 7.0-8.0 (the pH is adjusted according to Table 1).

[0090] Secondly, the reverse osmosis membrane sample needs to be soaked in deionized water or distilled water for 30 minutes, and then the reverse osmosis membrane sample can be installed into the reverse osmosis membrane evaluation tank 6. The desalination layer should face the water inlet side of the reverse osmosis membrane evaluation tank 6, that is, the side close to the test solution chamber 660. The conductivity of ionized water or distilled water should be less than 10μS / cm.

[0091] Furthermore, when selecting NaCl, hydrochloric acid or sodium hydroxide, the purity should be analyzed to determine its purity.

[0092] S3. Open the stop valve 9 between the test solution water tank 1 and the reverse osmosis membrane evaluation tank 6, adjust the booster pump 2, adjust the operating pressure according to the type of reverse osmosis membrane (the pressure is adjusted according to Table 1), and after the required operating time, collect a certain amount of test solution in a beaker, measure the volume of the permeate within a certain period of time with a stopwatch and a measuring cylinder 13, and measure the conductivity of the test solution and the permeate respectively, or measure the total dissolved solids content of the test solution and the permeate respectively.

[0093] The time required here is preferably 30 minutes, and it needs to be operated at a constant temperature and pressure. After the operation is completed, the stop valve 9 between the test solution tank 1 and the reverse osmosis membrane evaluation tank 6 is closed to reduce the operating pressure to below 0.05 MPa.

[0094] In addition, the volume of the test solution collected in the beaker should not be less than 150 mL.

[0095] Secondly, the above-mentioned measurement of the conductivity of the test solution and the permeate is measured in accordance with the provisions of GB / T / 6908; the above-mentioned measurement of the total dissolved solids content of the test solution and the permeate is measured separately in accordance with the provisions of GB / T / 5750.4.

[0096] S4, calculating the desalination rate and water flux of the reverse osmosis membrane sample according to the measurement result of S3, and calculating the initial average desalination rate according to the desalination rate, and calculating the initial average water flux according to the water flux, to obtain the initial average desalination rate and the initial average water flux;

[0097] S5, adjust the operating pressure to 1.5 times the test pressure and run it for the required time, then adjust the stop valve 9 to adjust the operating pressure to the normal test pressure, and calculate the average salt rejection rate and average water flux of the reverse osmosis membrane sample after high pressure according to the calculation method in S4;

[0098] The time required here is preferably 180 minutes, and it is operated stably at a constant temperature and pressure.

[0099] Finally, adjust the operating pressure to the normal test pressure.

[0100] S6, calculating the desalination rate change rate and the water flux change rate according to the initial average desalination rate and the initial average water flux in S4 and the average desalination rate after high pressure and the average water flux after high pressure in S5;

[0101] S7. The compressive strength of the reverse osmosis membrane is obtained by the change rate of the desalination rate and the change rate of the water flux.

[0102] First, the first method for calculating the desalination rate in S4 is provided: The method for calculating the desalination rate of the reverse osmosis membrane sample in S4 mentioned above by conductivity is: ) x 100%, where R is the desalination rate, k p is the conductivity of the permeate, in microSiemens per centimeter (μS / cm), k f The conductivity of the test solution is expressed in microSiemens per centimeter (μS / cm). The initial average desalination rate is calculated in S4 as follows: n, where R2 is the initial average desalination rate of the sample, R is the desalination rate of the i-th sample in the sample, and n is the total number of samples in the sample.

[0103] Secondly, another method for calculating the desalination rate is provided. The method for calculating the desalination rate in S4 is: ) x 100%, where R is the desalination rate, C P is the total dissolved solid content of the permeate, expressed in milligrams per liter (mg / L), Cf The total dissolved solid content of the test solution is expressed in milligrams per liter (mg / L). The method for calculating the initial average desalination rate in S4 is still n, where R2 is the initial average desalination rate of the sample, R is the desalination rate of the i-th sample in the sample, and n is the total number of samples in the sample.

[0104] The method for calculating the water permeability of the reverse osmosis membrane sample in S4 mentioned above is: ; Where F is the water flux, in liters per square meter hour L / (m²·h); v is the volume of permeate collected in time t, in liters (L); a is the effective membrane area, in square meters (m²), and t is the time taken to collect v volumes of permeate, in hours (h). The method for calculating the initial average water flux of the reverse osmosis membrane sample in S4 is: n, where F2 is the initial average water flux in liters per square meter per hour [L / (m²·h)]; F i is the water flux of the i-th reverse osmosis membrane sample, in liters per square meter per hour [L / (m²·h)]; n is the total number of reverse osmosis membrane samples tested in the sample.

[0105] In S5, the average desalination rate and the average water flux after high pressure of the reverse osmosis membrane sample calculated by the calculation method in S4 are R3 and F3 respectively, and the desalination rate change rate △R and the water flux change rate △F are calculated respectively.

[0106] The calculation method of the change rate of desalination rate is △R=( - ) / ×100%, where △R is the change rate of desalination rate, R3 is the average desalination rate of the sample after high pressure, and R2 is the initial average desalination rate; the calculation method of the water flux change rate in S6 is △F=( - ) / ×100%, where △F is the water flux change rate of the sample; F2 is the initial average water flux of the sample, in liters per square meter hour [L / (m²·h)]; F3 is the average water flux of the sample after high-pressure operation, in liters per square meter hour [L / (m²·h)].

[0107] In summary, the strength of the reverse osmosis membrane can be characterized by the water flux change rate and the desalination rate change rate. The specific method for calculating the strength of the reverse osmosis membrane is: ,in is the strength of the reverse osmosis membrane, is the influence weight of the change rate of desalination rate, is the influence weight of the water flux change rate, that is, the greater the water flux change rate and the desalination rate change rate, the smaller the strength of the reverse osmosis membrane; conversely, when the water flux change rate and the desalination rate change rate are smaller, the strength of the reverse osmosis membrane is greater.

[0108] The following table is Table 1:

[0109]

[0110] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0111] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A reverse osmosis membrane strength testing device, characterized in that: include: A reverse osmosis membrane evaluation pool (6), the reverse osmosis membrane evaluation pool (6) comprising a pool body (610), a reverse osmosis membrane (5) being placed in the pool body (610), the reverse osmosis membrane (5) dividing the pool body (610) into a test solution chamber (660) and a permeate solution chamber; A test solution water tank (1), the test solution water tank (1) is used to store and provide the test solution required by the test solution chamber (660), and the test solution chamber (660) and the permeation solution chamber are both provided with pipelines for connecting to the test solution water tank (1); A booster pump (2), the booster pump (2) being arranged on a pipeline connecting the test solution tank (1) and the test solution chamber (660), and the booster pump (2) being used to increase the pressure of the test solution entering the test solution chamber (660); Detecting the desalination rate and water flux of the permeate and the test solution before and after the booster pump (2) works, so as to characterize the strength of the reverse osmosis membrane (5); The cell body (610) is provided with a double clamping structure, the double clamping structure being composed of two groups of single clamping structures, and the two groups of single clamping structures are distributed on both sides of the reverse osmosis membrane (5); The single clamping structure comprises a point pressure head (641), at least two of the point pressure heads (641) are provided, and the point pressure heads (641) are in point-to-face contact with the reverse osmosis membrane (5), and a hollow bracket (630) is provided on a side of the point pressure head (641) away from the reverse osmosis membrane (5); The two groups of point pressure heads (641) of the single clamping structure are positioned opposite to each other, so that the two groups of point pressure heads (641) clamp the reverse osmosis membrane (5) in a point-to-point manner, thereby reducing the coverage area of ​​the reverse osmosis membrane (5).

2. A reverse osmosis membrane strength testing device according to claim 1, characterized in that: The clamping structure also includes: A gap lifting rod (640), wherein the gap lifting rod (640) is located between the point-type pressing head (641) and the hollow bracket (630), so that there is a gap between the point-type pressing head (641) and the hollow bracket (630); A porous plate (680), the porous plate (680) being located on a side of the hollow support (630) close to the reverse osmosis membrane (5), and the porous plate (680) being nested in an end of the gap lifting rod (640) close to the point pressure head (641), an elastic member (690) being provided between the porous plate (680) and the hollow support (630), and in a natural state of the elastic member (690), the porous plate (680) does not contact the reverse osmosis membrane (5); An approach structure (650), wherein the approach structure (650) is located between the two groups of porous plates (680), and the approach structure (650) is used to drive the two groups of porous plates (680) to move relative to or towards each other; The hollowing degree of the porous plate (680) in the permeable solution chamber is greater than the hollowing degree of the porous plate (680) in the test solution chamber (660); When the boost pump (2) increases pressure, the hydraulic pressure in the test solution chamber (660) increases instantaneously, so as to push the porous plate (680) in the test solution chamber (660) to be pressed against the filtering surface of the reverse osmosis membrane (5). The porous plate (680) in the test solution chamber (660) pushes another set of porous plates (680) to be pressed against the filtering back side of the reverse osmosis membrane (5) through the approach structure (650), so that the two sets of porous plates (680) clamp the reverse osmosis membrane (5) when the pressure is increased instantaneously.

3. A reverse osmosis membrane strength testing device according to claim 1 or 2, characterized in that: A stop valve (9) and a pressure gauge (4) are provided on the pipeline between the booster pump (2) and the test solution chamber (660), on the pipeline between the permeate solution chamber and the test solution water tank (1), and on the pipeline between the test solution chamber (660) and the test solution water tank (1); Flow meters (10) are provided on the pipelines of the test solution chamber (660) and the test solution water tank (1), and the flow meters (10) are used to detect the flow rate of liquid passing through the pipelines.

4. A reverse osmosis membrane strength testing method, characterized in that: The following steps are involved: S1. Take a reverse osmosis membrane sample and soak it in deionized water or distilled water for later use; S2. Prepare a NaCl water solution of corresponding concentration according to the type of reverse osmosis membrane as a test solution and adjust the pH to 7.5 with hydrochloric acid or sodium hydroxide for later use; S3, opening the stop valve (9), adjusting the booster pump (2), adjusting the operating pressure according to the type of membrane, and after the required operating time, collecting a certain amount of the test solution in a beaker, measuring the volume of the permeate within a certain period of time with a stopwatch and a measuring cylinder (13), and measuring the conductivity of the test solution and the permeate respectively, or measuring the total dissolved solid content of the test solution and the permeate respectively; S4, calculating the desalination rate and water flux of the reverse osmosis membrane sample according to the measurement result of S3, and calculating the initial average desalination rate according to the desalination rate, and calculating the initial average water flux according to the water flux, to obtain the initial average desalination rate and the initial average water flux; S5, adjust the operating pressure to 1.5 times the test pressure and run for the required time, then adjust the stop valve (9) to adjust the operating pressure to the normal test pressure, and calculate the average salt rejection rate and average water flux of the reverse osmosis membrane sample after high pressure according to the calculation method in S4; S6, calculating the desalination rate change rate and the water flux change rate according to the initial average desalination rate and the initial average water flux in S4 and the average desalination rate after high pressure and the average water flux after high pressure in S5; S7, obtaining the compressive strength of the reverse osmosis membrane through the change rate of desalination rate and the change rate of water flux; The method for calculating the salt rejection rate of the reverse osmosis membrane sample in S4 by conductivity is as follows: Where R is the desalination rate, k p is the conductivity of the permeate, k f To test the solution conductivity; The method for calculating the initial average desalination rate in S4 is: Where R2 is the initial average desalination rate of the sample, R is the desalination rate of the i-th sample in the sample, and n is the total number of samples in the sample; The method for calculating the salt rejection rate by the total dissolved solid content in S4 is: Where R is the desalination rate, C P is the total dissolved solid content of the permeate, C f To test the total soluble solid content of the solution; The method for calculating the initial average desalination rate in S4 is: Where R2 is the initial average desalination rate of the sample, R is the desalination rate of the i-th sample in the sample, and n is the total number of samples in the sample; The method for calculating the water permeability of the reverse osmosis membrane sample in S4 is: Where F is the water flux, v is the volume of permeate collected in time t; a is the effective membrane area, and t is the time taken to collect v volume of permeate; The method for calculating the initial average water flux of the reverse osmosis membrane sample in S4 is: Among them, F2 is the initial average water flux, F i is the water flux of the i-th reverse osmosis membrane sample, and n is the total number of reverse osmosis membrane samples tested in the sample.

5. A reverse osmosis membrane strength testing method according to claim 4, characterized in that: In S5, the average salt rejection rate and the average water flux after high pressure of the reverse osmosis membrane sample are calculated by the calculation method of S4, which are R3 and F3 respectively; The calculation method of the change rate of desalination rate in S6 is △R = (R3-R2) / R2×100%, where △R is the change rate of desalination rate, R3 is the average desalination rate of the sample after high pressure, and R2 is the initial average desalination rate; The calculation method of the water flux change rate in S6 is △F=(F3-F2) / F2×100%, where △F is the water flux change rate of the sample; F2 is the initial average water flux of the sample, and F3 is the average water flux of the sample after high-pressure operation.

6. A reverse osmosis membrane strength testing method according to claim 5, characterized in that: The method for calculating the strength of the reverse osmosis membrane by the water flux change rate and the salt rejection rate change rate is as follows: Where ξ is the strength of the reverse osmosis membrane, λ1 is the influence weight of the desalination rate change rate, and λ2 is the influence weight of the water flux change rate.

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