Concentrated water separation net, reverse osmosis membrane assembly and filter element
By designing a concentrated water partition network with a water-through area and a resistance-reducing area, the problems of turbulence unevenness and increased flow resistance caused by conventional concentrated water partition networks are solved, and the effect of improving the turbulence uniformity of the reverse osmosis membrane surface and extending the service life of the filter element is achieved.
Patent Information
- Application Number
- CN202421414620.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-19
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-06-19
AI Technical Summary
During operation, conventional concentrated water separators can easily lead to uneven turbulence on the surface of the reverse osmosis diaphragm and increase in flow resistance, which in turn leads to an increase in the flux attenuation rate.
A concentrated water barrier mesh is designed, including a water-passing area and a resistance-reducing area, and is woven by mesh wires. The mesh is twisted by fiber wires, and the gaps between the fiber wires are arranged as passages to reduce flow resistance.
By setting up a water-through area and a resistance-reducing area, the flow resistance is reduced, the turbulence uniformity of the reverse osmosis membrane surface is improved, the flux attenuation rate is reduced, and the service life of the filter element is extended.
Smart Images
Figure CN223027092U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of water treatment, and particularly relates to a concentrated water spacer, a reverse osmosis membrane module and a filter element. Background Art
[0002] The reverse osmosis membrane module is the core component of the reverse osmosis system. Generally, it is in a cylindrical shape. Specifically, the membrane sheets for filtration, concentrated water spacers, etc. are wound around the central collecting pipe to form a cylindrical and long-shaped spiral membrane element, which can be used in water treatment and separation processes.
[0003] Among them, the concentrated water spacer is an important part of the reverse osmosis membrane module. Its main function is to support the flow channel and slow down the concentration polarization phenomenon and membrane fouling. The conventional concentrated water spacer is formed by extrusion molding of polypropylene through a mold. During operation, it is easy to cause problems such as uneven turbulence on the surface of the reverse osmosis membrane sheet and an increase in flow resistance, thereby leading to an increase in the flux decay rate. Summary of the Utility Model
[0004] The main purpose of the utility model is to propose a concentrated water spacer, a reverse osmosis membrane module and a filter element, aiming to improve the problems of uneven turbulence on the surface of the reverse osmosis membrane sheet and an increase in flow resistance.
[0005] To achieve the above object, the concentrated water spacer of the utility model is provided with a water passing area and a resistance reducing area. A plurality of grids on the concentrated water spacer are set as the water passing area, and the passages provided on the grid wires are set as the resistance reducing area.
[0006] In one embodiment, the concentrated water spacer is woven by grid wires, and the grid wires are twisted by fiber wires. The gaps between the fiber wires are set as the passages.
[0007] In one embodiment, the fiber wires are selected from one of polypropylene and polyester.
[0008] In one embodiment, the grid of the concentrated water spacer is quadrilateral, and the linear density of the grid is 22 - 26.
[0009] In one embodiment, the grid of the concentrated water spacer is hexagonal, and the grid has a first grid wire and a second grid wire arranged at intervals in the a direction, a third grid wire and a fourth grid wire arranged at intervals in the b direction, and a fifth grid wire and a sixth grid wire arranged at intervals in the c direction; the first grid wire, the second grid wire, the third grid wire, the fourth grid wire, the fifth grid wire and the sixth grid wire enclose to form the grid.
[0010] In one embodiment, the linear densities of the grid wires in two of the a direction, b direction and c direction are the same.
[0011] In one embodiment, the grid has a first linear density and a second linear density, the first linear density is 20 - 24; and / or, the second linear density is 14 - 18.
[0012] In one embodiment, the thickness of the concentrated water separation grid is 0.21 mm - 0.70 mm.
[0013] The present utility model also provides a reverse osmosis membrane module, which includes a central tube, a reverse osmosis membrane, and the above-mentioned concentrated water separation grid.
[0014] The present utility model also provides a filter element, which includes the above-mentioned reverse osmosis membrane module.
[0015] On the concentrated water separation grid of the present utility model, there are a water passing area and a flow resistance reduction area. The flow resistance reduction area is formed by passages provided on the filaments of the grid. When water flows through, the passages on the filaments of each grid can also supply water to flow through, which can achieve the purpose of reducing the flow resistance, thereby realizing the purpose of improving the turbulence uniformity on the surface of the reverse osmosis membrane and reducing the flux attenuation rate. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present utility model, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.
[0017] Figure 1 It is a schematic structural diagram of the concentrated water separation grid in an embodiment of the present utility model;
[0018] Figure 2 It is a schematic structural diagram of the concentrated water separation grid in another embodiment of the present utility model;
[0019] Figure 3 It is a schematic structural diagram of the concentrated water separation grid in the comparative example.
[0020] DESCRIPTION OF THE REFERENCE NUMERALS IN THE DRAWINGS
[0021] 100, concentrated water separation grid; 101, water passing area; 102, flow resistance reduction area. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. Additionally, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes Scenario A, or Scenario B, or the scenario where both A and B are satisfied simultaneously. "At least one" as used in the embodiments of the present utility model refers to one or more, and "a plurality" refers to two or more.
[0023] The "range" disclosed in the present utility model is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of the specific range. The ranges defined in this way can include the end values or not include the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In the present utility model, unless otherwise stated, the numerical range "a - b" represents an abbreviated representation of any real number combination between a and b, where both a and b are real numbers. For example, the numerical range "0 - 5" represents that all real numbers between "0 - 5" have been fully listed herein, and "0 - 5" is only an abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0024] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.
[0025] The concentrated water spacer is an important part of the reverse osmosis membrane module, and its main functions are to support the flow channel and mitigate the concentration polarization phenomenon and membrane fouling. Conventional concentrated water spacers are formed by extrusion molding of polypropylene through a mold. Each grid is independent, and the filaments of the grid are impermeable to water. During operation, it is prone to problems such as uneven surface turbulence and increased flow resistance of the reverse osmosis membrane sheet, resulting in an increased flux decay rate.
[0026] To this end, the present utility model provides a concentrated water separation net, on which a water passing area and a resistance reduction area are provided. Multiple grids on the concentrated water separation net are set as the water passing area, and the passages provided on the filaments of the grids are set as the resistance reduction area.
[0027] The concentrated water separation net of the present utility model is provided with a resistance reduction area, which is formed by the passages provided on the filaments of the grids. When water flows through, the passages on the filaments of each grid can also supply water to flow through, which can achieve the purpose of reducing flow resistance, thereby realizing the purpose of improving the turbulence uniformity on the surface of the reverse osmosis membrane and reducing the flux attenuation rate.
[0028] In an embodiment of the present utility model, the concentrated water separation net is woven by filaments, the filaments are twisted by fiber filaments, and the gaps between the fiber filaments are set as the passages.
[0029] The filaments are twisted by fiber filaments means that two or more fiber filaments are combined together by mechanical twisting, so that the gaps between the multiple fiber filaments can form passages without additional processing.
[0030] The concentrated water separation net is woven by filaments means that the filaments are woven according to the interlaced warp and weft. The concentrated water separation net woven by filaments has lower overall strength compared with the concentrated water separation net formed by extrusion molding. When the reverse osmosis membrane module operates, it can improve the situation of the membrane being damaged by the separation net extrusion, thereby improving the desalination rate.
[0031] In an embodiment of the present utility model, the fiber filaments are selected from one of polypropylene and polyester.
[0032] Polyester includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate (PC), and polyarylate (PAR). The concentrated water separation net made of polypropylene or polyester materials has good chemical stability, anti-pollution property, and mechanical properties.
[0033] In an embodiment of the present utility model, the grids of the concentrated water separation net are quadrilateral, and the linear density of the grids is 22-26.
[0034] The linear density of the grids refers to the number of filaments on the concentrated water separation net per inch of length. The level of the linear density reflects the density of the grids on the concentrated water separation net and also reflects the size of the holes allowing water to pass through. Therefore, the linear density of the filaments will affect the open area, water flow distribution, pressure loss, and membrane pollution of the concentrated water separation net.
[0035] Theoretically, the higher the wire density, the better the turbulent flow effect of the concentrated water, the smaller the concentration polarization phenomenon, and the better the anti-scaling effect. However, the higher the wire density, the more precise the production mold requirements, and the higher the cost. Therefore, when the concentrated water separation net of the present utility model is applied to a household water purifier, setting the wire density of the quadrilateral grid to 22-26 can achieve a longer service life and price competitiveness.
[0036] In an embodiment of the present utility model, the grid of the concentrated water separation net is hexagonal, and the grid has a first wire and a second wire arranged at intervals in the a direction, a third wire and a fourth wire arranged at intervals in the b direction, and a fifth wire and a sixth wire arranged at intervals in the c direction; the first wire, the second wire, the third wire, the fourth wire, the fifth wire, and the sixth wire enclose to form the grid.
[0037] In this embodiment, the grid is set to be hexagonal. Such a grid structure has a large number of included angles and large angles. During the operation of the reverse osmosis membrane module, the flow resistance at the included angles will decrease, and the area of the dead water area will decrease. On the one hand, it can improve the scaling phenomenon, and on the other hand, it can also achieve the effect of improving the uniformity of turbulent flow, thereby improving the desalination rate and service life of the reverse osmosis membrane module.
[0038] In addition, in this embodiment, the first wire and the second wire are arranged in parallel, the third wire and the fourth wire are arranged in parallel, and the fifth wire and the sixth wire are arranged in parallel, forming a grid that is an axisymmetric hexagon and has two axes of symmetry, which is easy to process.
[0039] In an embodiment of the present utility model, the wire densities of the wires in two of the a direction, the b direction, and the c direction are the same. That is, the wire densities of the first wire, the second wire, the third wire, and the fourth wire are the same, and the wire densities of the fifth wire and the sixth wire are the same; or, the wire densities of the first wire, the second wire, the fifth wire, and the sixth wire are the same, and the wire densities of the third wire and the fourth wire are the same; or, the wire densities of the third wire, the fourth wire, the fifth wire, and the sixth wire are the same, and the wire densities of the first wire and the second wire are the same.
[0040] This embodiment sets different wire densities, which is beneficial for the reverse osmosis membrane module to achieve better use effects and cost performance in different usage environments.
[0041] In an embodiment of the present utility model, the grid has a first wire density and a second wire density. The first wire density is 20 - 24; and / or, the second wire density is 14 - 18. That is, the wire densities of the first wire, the second wire, the third wire, and the fourth wire can be set to 14 - 18, and the wire densities of the fifth wire and the sixth wire are 20 - 24; or the wire densities of the first wire, the second wire, the third wire, and the fourth wire are set to 20 - 24, and the wire densities of the fifth wire and the sixth wire are 14 - 18; or the wire densities of the first wire, the second wire, the fifth wire, and the sixth wire are set to 14 - 18, and the wire densities of the third wire and the fourth wire are 20 - 24; or the wire densities of the first wire, the second wire, the fifth wire, and the sixth wire are set to 20 - 24, and the wire densities of the third wire and the fourth wire are 14 - 18; or the wire densities of the third wire, the fourth wire, the fifth wire, and the sixth wire are set to 14 - 18, and the wire densities of the first wire and the second wire are 20 - 24; or the wire densities of the third wire, the fourth wire, the fifth wire, and the sixth wire are set to 20 - 24, and the wire densities of the first wire and the second wire are 14 - 18. Through test verification, when the concentrated water separation grid of the present utility model is applied to a household water purifier, setting the first wire density to 20 - 24 and the second wire density to 14 - 18 can achieve a longer service life and price competitiveness.
[0042] In an embodiment of the present utility model, the thickness of the concentrated water separation grid is 0.21 mm - 0.70 mm.
[0043] The thickness of the concentrated water separation grid affects the distribution of water flow on the membrane surface, the pressure loss during water passage, and the membrane fouling rate. The thickness range of this embodiment can achieve a more uniform water flow distribution, avoid pressure loss caused by high water flow resistance, and reduce membrane fouling.
[0044] The present utility model also proposes a reverse osmosis membrane module, including a central tube, a reverse osmosis membrane, and the above-mentioned concentrated water separation grid. The specific setting of the concentrated water separation grid refers to the above-mentioned embodiment. Since the reverse osmosis membrane module of the present utility model adopts all the technical solutions of the above-mentioned all embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated here one by one.
[0045] To improve the water treatment efficiency and water quality of the reverse osmosis membrane module, multiple groups of reverse osmosis membranes can be specifically set, and a concentrated water separation grid is arranged between each adjacent two groups of reverse osmosis membranes. Arranging the concentrated water separation grid between the reverse osmosis membranes can help maintain a certain flow channel space, prevent the reverse osmosis membranes from adhering due to pressure, thereby ensuring smooth water flow. In addition, arranging the concentrated water separation grid between the reverse osmosis membranes can also prevent direct contact between the reverse osmosis membranes, reducing pollution and scaling on the membrane surface.
[0046] The present utility model also provides a filter element, which includes the above-mentioned reverse osmosis membrane module. For the specific setting of the reverse osmosis membrane module, reference can be made to the above-mentioned embodiments. Since the filter element of the present utility model adopts all the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated herein one by one.
[0047] The following will be described in conjunction with specific embodiments.
[0048] Embodiment 1
[0049] In this embodiment, the concentrated water separation net 100 is woven from polyethylene terephthalate fibers. Specifically, multiple strands of polyethylene terephthalate fiber filaments are twisted into net filaments, and then the concentrated water separation net is formed by weaving the net filaments. Refer to Figure 1 As shown, the concentrated water separation net 100 is provided with a water passing area 101 and a resistance reducing area 102. The water passing area 101 is formed by a plurality of grids, and the resistance reducing area 102 is formed by the passages existing on the net filaments.
[0050] The thickness of the concentrated water separation net 100 is 0.34 mm, its grid is quadrilateral, specifically rhombus, and the linear density of the grid is 24.
[0051] Embodiment 2
[0052] Different from Embodiment 1, in this embodiment, the grid of the concentrated water separation net is hexagon. Refer to Figure 2 As shown, the grid of the concentrated water separation net is formed by enclosing the first net filament, the second net filament arranged at intervals along the a direction, the third net filament, the fourth net filament arranged at intervals along the b direction, the fifth net filament, and the sixth net filament arranged at intervals along the c direction. The linear densities of the first net filament, the second net filament, the third net filament, and the fourth net filament are the same, all being 18, and the linear densities of the fifth net filament and the sixth net filament are the same, all being 22.
[0053] Comparative Example
[0054] The concentrated water separation net is formed by polypropylene extrusion molding, and its thickness is 0.34 mm. Refer to Figure 3 As shown, the grid of the concentrated water separation net is quadrilateral, specifically rhombus, and the linear densities of the four net filaments of the concentrated water separation net are all 24.
[0055] Performance Test
[0056] The concentrated water separation nets in Embodiment 1, Embodiment 2, and the Comparative Example are respectively assembled with components such as reverse osmosis membranes according to conventional methods to form a reverse osmosis membrane (RO membrane) module, and the performance of the RO membrane module is tested.
[0057] Testing method for new water efficiency flux: Test the pure water production rate of the RO membrane module within 1 minute, with the unit of L / min, and then convert it to flux expressed in GPD. GPD represents gallons per day, and the conversion method is: 1 L / min = 2.6286 × 1 GPD.
[0058] Testing method for new water efficiency desalination rate: Test the total amount of all dissolved solids (TDS value) in the feed water and pure water of the RO membrane module respectively, and calculate the desalination rate through formula (I):
[0059] (Feed water TDS value - Pure water TDS value) / Feed water TDS value × 100% Formula (I).
[0060] Testing method for new water efficiency life attenuation rate: Test the initial flux of the RO membrane module as the background value A1, and the flux during the operation under working conditions as A2, and calculate the attenuation rate through formula (II):
[0061] (A1 - A2) / A1 × 100% Formula (II).
[0062] The above testing methods are all carried out under the conditions that the feed water quality is the new water efficiency water quality (GB 34914-2021 Water efficiency limit value and water efficiency grade for water purifiers), the pre-membrane pressure is 0.7 MPa, and the recovery rate is 70% - 75%.
[0063] Test results
[0064] The new water efficiency initial flux of the filter element in Example 1 is 935 GPD, and the new water efficiency 4T life flux (the water production volume of 4000 L of pure water) is 865 GPD; the new water efficiency initial flux of the filter element in Example 2 is 939 GPD, and the new water efficiency 4T life flux is 890 GPD; the new water efficiency initial flux of the filter element in the comparative example is 937 GPD, and the new water efficiency 4T life flux is 837 GPD. Although there is no significant difference in the initial flux between the filter elements in Examples 1 and 2 and the filter element in the comparative example, the new water efficiency 4T life flux of the filter elements in Examples 1 and 2 is significantly higher than that in the comparative example, indicating that the concentrated water spacer of the present invention can improve the 4T life flux of the filter element. Comparing Examples 1 and 2, it can be seen that the hexagonal grid can further improve the 4T life flux of the filter element compared with the quadrilateral grid.
[0065] The new water efficiency initial desalination rate of the filter element in Example 1 is 91.54%, and the new water efficiency life desalination rate is 95.60%; the new water efficiency initial desalination rate of the filter element in Example 2 is 92.64%, and the new water efficiency life desalination rate is 96.33%, while the new water efficiency initial desalination rate of the filter element in the comparative example is 90.62%, and the new water efficiency life desalination rate is 94.56%, indicating that the concentrated water spacer of the present invention can improve the desalination rate of the filter element. Comparing Examples 1 and 2, it can be seen that the hexagonal grid can further improve the desalination rate of the filter element compared with the quadrilateral grid.
[0066] On the basis of configuring a pre-filter for scale inhibition, the attenuation rate of the new water efficiency life of the filter element in Example 1 is 7.49%; the attenuation rate of the new water efficiency life of the filter element in Example 2 is 5.20%; while the attenuation rate of the new water efficiency life of the filter element in the comparative example is 10.67%, indicating that the concentrated water partition net of the present invention can reduce the flow resistance, thereby reducing the attenuation rate of the filter element and increasing the service life of the filter element. By comparing Example 1 and Example 2, it can be seen that the hexagonal grid can further reduce the attenuation rate of the filter element compared with the quadrilateral grid.
[0067] The above description is only an exemplary embodiment of the present utility model, and does not limit the patent scope of the present utility model. Any equivalent structural transformation made under the technical concept of the present utility model by using the content of the specification and drawings of the present utility model, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present utility model.
Claims
1. A concentrated water screen, characterized in that: The concentrated water isolation net is provided with a water passing area and a drag reduction area, a plurality of grids on the concentrated water isolation net are set as the water passing area, and a passage provided on the mesh wire of the grid is set as the drag reduction area; The concentrated water separator is woven by mesh wires, and the mesh wires are formed by twisting fiber wires, and the gaps between the fiber wires are set as the passages.
2. The concentrated water screen according to claim 1, characterized in that: The fiber filaments are selected from one of polypropylene and polyester.
3. The concentrated water screen according to claim 1, characterized in that: The grid is quadrilateral, and the line density of the grid is 22-26.
4. The concentrated water screen according to claim 1, characterized in that: The grid is hexagonal, and the grid has a first mesh and a second mesh arranged at intervals along the a direction, a third mesh and a fourth mesh arranged at intervals along the b direction, and a fifth mesh and a sixth mesh arranged at intervals along the c direction; The first mesh, the second mesh, the third mesh, the fourth mesh, the fifth mesh and the sixth mesh together form the grid.
5. The concentrated water screen as claimed in claim 4, characterized in that: The linear density of the mesh fibers in two directions among the a direction, the b direction, and the c direction is the same.
6. The concentrated water screen as claimed in claim 5, characterized in that: The grid has a first line density and a second line density, the first line density being 20-24; And / or, the second linear density is 14-18.
7. The concentrated water screen as claimed in claim 1, characterized in that: The thickness of the concentrated water separator is 0.21mm-0.70mm.
8. A reverse osmosis membrane assembly, characterized in that: The invention comprises a central tube, a reverse osmosis membrane and the concentrated water separator according to any one of claims 1 to 7.
9. A filter element, characterized in that: Comprising the reverse osmosis membrane assembly according to claim 8.