Raw water partial flow directing membrane element and filter cartridge

Abstract

The application discloses a raw water local flow guide membrane element and a filter core, and belongs to the water purification field. The membrane element is used for cross-flow filtration; at least one membrane bag and a raw water flow guide net arranged on the inner side of the membrane sheet are included; each membrane bag has two opposite membrane sheets; the inner side of the membrane sheet forms a raw water flow channel which is communicated with a raw water inlet and a concentrated water outlet of the membrane bag, and the concentrated water outlet is located at the position of the first short side; the outer side of the membrane sheet forms a pure water flow channel; the raw water flow guide net is substantially equal to the second short side in the width direction, the raw water flow guide net is partially arranged in the length direction, and the raw water flow guide net covers the raw water inlet area. In the scheme, the water flow speed of the concentrated water end of the raw water side is automatically increased, so that the blockage is avoided, and the anti-pollution ability is high. Longer membrane bags can be arranged in the same space, and the water purification capacity is also significantly improved.

Description

Technical Field

[0001] This invention relates to the field of water purification technology, and more specifically, to a raw water local flow guiding membrane element and filter cartridge. Background Technology

[0002] Existing spiral-wound reverse osmosis membrane elements use feed water guide nets with a uniform thickness and weave density. As some of the feed water permeates to the back of the reverse osmosis membrane to form pure water, the feed water flow rate gradually decreases. This decrease in feed water flow rate along the flow path also leads to a reduction in flow velocity. This reduced velocity creates a difference in flow rate between the feed and concentrate ends of the reverse osmosis membrane element, directly causing concentration polarization. This intensified concentration polarization at the concentrate end accelerates fouling of the membrane surface in this region, resulting in reduced desalination rate and permeate flow, and a shortened membrane element lifespan.

[0003] To solve this problem, Figure 1 The illustrated solution is a scheme disclosed in patent CN201120187959.2. Its reverse osmosis membrane, after folding, forms three folds on the side of the central tube. The middle fold extends into the inlet channel, dividing the inlet channel into upper and lower inlet channels on the side of the central tube and a rear inlet channel on the side of the concentrate outlet. The inlet guide net is divided into a large inlet guide net and a small inlet guide net. The large inlet guide net is placed in one of the inlet and rear inlet channels, while the small inlet guide net is placed only in the other inlet channel. This patent essentially increases the inlet flow rate by increasing the thickness on the inlet side, and then increases the flow velocity at the end of the raw water supply by creating a thickness difference. This results in an increase in overall volume, and for the same volume, a decrease in the inlet flow rate.

[0004] Patent CN208542034U discloses a spiral wound membrane element. This design sets the thickness of the raw water inlet and product water inlet meshes in the spiral wound membrane element to be gradient-distributed along the direction from the raw water inlet to the concentrate outlet, increasing the linear velocity of the concentrate outlet and making the membrane element less prone to clogging, thus increasing the desalination rate and fouling resistance. While this design has theoretical significance, in actual production, because it uses a soft rubber material with a thickness of less than 1mm, it is difficult to achieve a gradient distribution between the thicknesses of the raw water inlet mesh and the product water inlet mesh, making it technically challenging.

[0005] Therefore, how to reduce the possibility of blockage on the raw water side of membrane elements and improve the antifouling ability and lifespan of membrane elements remains an unsolved problem. Summary of the Invention

[0006] 1. The technical problem that the invention aims to solve

[0007] The purpose of this invention is to reduce the likelihood of clogging on the feed water side of membrane elements, improve the fouling resistance and lifespan of membrane elements, and provide an adaptive flow channel membrane element and filter cartridge. In this solution, the water flow velocity at the concentrate end on the feed water side automatically increases, thereby avoiding clogging, resulting in strong fouling resistance and a longer lifespan.

[0008] 2. Technical Solution

[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0010] This invention provides a raw water localized flow guiding membrane element for cross-flow filtration; comprising:

[0011] At least one membrane bag, the membrane bag having a first long side and a second long side, and a first short side and a second short side, wherein after the membrane is rolled up, the first short side is located on the outermost layer; a raw water guide net is disposed on the inner surface of the membrane sheet;

[0012] Each membrane bag has two opposing membrane sheets. The inner surface of the membrane sheets forms a raw water channel, which connects the raw water inlet and the concentrate outlet of the membrane bag, and the concentrate outlet is located at the first short side. The outer surface of the membrane sheets forms a pure water channel.

[0013] The raw water diversion network is approximately equal in width to the second short side, and is partially installed in length, covering the raw water inlet area.

[0014] As a further improvement, the raw water inlet is located at the second short side of the inner side of the diaphragm, and a seal is formed at the first and second long sides.

[0015] As a further improvement, a seal is formed on the inner side of the membrane at the second short side, and a raw water inlet is provided on the first or second long side, which is close to one end of the second short side.

[0016] As a further improvement, a raw water inlet is provided on the inner side of the membrane near the middle of the first long side or the second long side, and a raw water guide net is provided in the area between the raw water inlet and the second short side; the first and second short sides are both used as concentrated water outlets.

[0017] As a further improvement, a pure water outlet is provided on the outer surface of the diaphragm at a local location on the first long side or the second long side, or at the second short side.

[0018] As a further improvement, the two membranes of the membrane bag are connected at the first long side by a folded cornea, and the folded cornea and the membranes are an integral structure;

[0019] Alternatively: one side of the folded cornea is an integral structure with the membrane, and the other side is connected to the membrane by adhesive bonding or thin film welding;

[0020] Alternatively: Both sides of the folded cornea are connected to the membrane by adhesive bonding or thin film welding.

[0021] As a further improvement, the thickness of the folded cornea is 0.01 to 0.08 mm and the softness is 2.0 to 20.0 g, so that it can eliminate the folds formed at the first long side when the cornea is rolled up.

[0022] As a further improvement, a seal is formed on the pure water side of the membrane bag at least near the first short side, the second short side, and the second long side, so that the filtered pure water flows out from the end where the first long side is located.

[0023] As a further improvement, it also includes a central tube and a pure water flow guiding cloth, which is disposed on one side of the membrane bag, and the pure water flow guiding cloth and the membrane bag are wound around the central tube from the second short side.

[0024] As a further improvement, the raw water diversion net surrounds at least 3 / 4 of the circumference of the central pipe in the circumferential direction.

[0025] A raw water local flow guiding membrane element of the present invention includes a membrane element and a central tube, wherein the membrane element is wound around the central tube, and the membrane element includes:

[0026] At least one film bag, the film bag having a first long side and a second long side, and a first short side and a second short side, and after the film is rolled up, the second short side is located in the innermost layer and the first short side is located in the outermost layer;

[0027] A raw water diversion net is disposed on the inner surface of the diaphragm;

[0028] Each membrane bag has two opposing membrane sheets. The inner surface of the membrane sheets forms a raw water channel, which connects the raw water inlet and the concentrate outlet of the membrane bag. The outer surface of the membrane sheets forms a pure water channel.

[0029] The raw water guide net is approximately equal to the second short side in the width direction, and is partially set in the length direction, covering the raw water inlet area. During operation, the pressure difference between the raw water inlet and the concentrate outlet causes a portion of the area between the two membranes to be opened by the water flow, forming an adaptive flow channel area.

[0030] As a further improvement, the raw water inlet is located on the side closer to the central pipe, and the concentrated water outlet is located at the first short side.

[0031] As a further improvement, the membrane has a certain deformation capability, and under water pressure, it can deform to form a flow channel, and the surface of the membrane element is a flat curved surface.

[0032] A filter element of the present invention includes the aforementioned membrane element, wherein the membrane element has an end cap at at least one end and an end cap or a Y-shaped sealing ring at the other end.

[0033] As a further improvement, a membrane housing is also included, in which the membrane element is installed, and a gap is provided between the inner wall of the membrane housing and the membrane element for the discharge of concentrate.

[0034] 3. Beneficial effects

[0035] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0036] The raw water localized flow guiding membrane element of the present invention has a raw water guiding net installed only in a localized area within its membrane bag, covering the main raw water inlet. This enables the formation of a raw water guiding effect. Furthermore, in areas not covered by the raw water guiding net, a water flow channel is automatically formed using pressure difference, automatically increasing the water flow velocity at the concentrate end of the raw water side. This prevents clogging, provides strong anti-fouling capabilities, and extends service life. In addition, by eliminating the space occupied by part of the raw water guiding net, more membrane sheets can be installed within the same radial dimension, resulting in a larger membrane area and a significant increase in purified water output. Attached Figure Description

[0037] Figure 1 A schematic diagram illustrating the existing method of setting up a flow guide network;

[0038] Figure 2 This is a schematic diagram of one embodiment of the original water diversion network in this application;

[0039] Figure 3 This is a schematic diagram of a short-side water inlet method for the membrane bag of this application;

[0040] Figure 4 A schematic diagram of a side-inlet water intake method for a membrane bag;

[0041] Figure 5 A schematic diagram of a central water inlet method for membrane bags;

[0042] Figure 6 A schematic diagram of one way to fold the long side of a membrane bag;

[0043] Figure 7 This is a schematic diagram of the inlet and outlet water structure after the membrane element is wound.

[0044] Figure 8 This is a schematic diagram of a non-contact membrane element structure.

[0045] Figure 9a A schematic diagram of a double-sided adhesive corneal flap connection structure;

[0046] Figure 9b This is a schematic diagram of a spliced, folded corneal connection structure;

[0047] Figure 10 This is a schematic diagram of one embodiment of the filter element structure.

[0048] Explanation of the labels in the diagram:

[0049] 1. Membrane; 101. First long side; 102. Second long side; 103. First short side; 104. Second short side; 105. Folded cornea; 120. Adhesive strip; 121. Main adhesive strip; 122. Side adhesive strip;

[0050] 2. Central tube; 201. Flow guide hole;

[0051] 3. Raw water diversion network;

[0052] 4. Pure water diversion cloth;

[0053] 51. First end cap; 501. Water collection chamber; 52. Second end cap. Detailed Implementation

[0054] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings and embodiments.

[0055] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0056] To address the issue of long pure water flow channels in water purifier filter cartridges, numerous solutions have been proposed in the industry, but their implementation is often complex or only theoretically feasible. In this context, the raw water localized flow guiding membrane element proposed in this application is presented.

[0057] Combination Figure 2 , Figure 3This embodiment of a raw water local flow guiding membrane element includes at least one membrane bag. The membrane bag has opposing first long sides 101 and second long sides 102, and opposing first short sides 103 and second short sides 104. The membrane bag is wound along the extending direction of the first long side 101. After winding, the first short side 103 is located in the outermost layer, and the second short side 104 is located in the innermost layer. To clearly illustrate the structure of the membrane element, this embodiment will describe it in conjunction with the unfolded state or the wound state of the membrane element, so as to clearly demonstrate the structure of the membrane element.

[0058] Each membrane bag has two opposing membrane sheets 1. The inner surface of the membrane sheet 1 forms a raw water flow channel, which connects the raw water inlet and the concentrate outlet of the membrane bag. The concentrate outlet is located at the first short side 103, allowing the raw water to flow from the inner layer to the outer layer around the membrane element. The outer surface of the membrane sheet 1 forms a pure water flow channel, and the filtered pure water flows out from the pure water outlet.

[0059] A raw water guide net 3 is provided on the inner side between the two diaphragms 1. The raw water guide net 3 is approximately equal to the second short side 104 in the width direction and is partially provided in the length direction. The raw water guide net 3 covers the raw water inlet area.

[0060] Figure 3 A specific water inlet implementation is illustrated, with the raw water inlet located at the second short side 104. The raw water guide net 3 is approximately equal in length to the second short side 104 in the width direction, and may have a certain length in the length direction so that it can wrap around the central pipe. Since the raw water enters from a direction perpendicular to the second short side 104, the raw water guide net 3 is at least adapted to the second short side 104 to allow the raw water to be introduced into the membrane bag.

[0061] It is worth noting that the term "approximately equal" in this application includes cases where the parts are equal and cases with a certain dimensional difference. For example, if the inside of the membrane bag serves as the raw water flow channel, the width of the raw water guide net 3 can be approximately equal to the width of the membrane 1; if the inside of the membrane bag is sealed with an adhesive strip, the adhesive strip will occupy a certain width, and although there is a certain width difference, the width of the raw water guide net 3 can still be considered approximately equal to the width of the membrane 1.

[0062] The outer surface of the diaphragm is the pure water side, which can form a water outlet channel using existing sealing methods. For example, it can have an opening on one of the two long sides, near the second short side 104 or the first short side 103, as a pure water outlet; the remaining part is sealed with a rubber strip to form a pure water channel.

[0063] In this embodiment, the concentrate outlet is located at the first short side 103, meaning the two membrane sheets 1 are not sealed at the first short side 103, forming a concentrate outlet for concentrate discharge. The wound membrane element has a raw water inlet in its inner layer, where the pressure is high. Under pressure, the two membrane sheets automatically open, forming a flowing water film of a certain thickness between them, causing water to flow automatically towards the concentrate outlet. The closer to the concentrate outlet, the lower the pressure on the raw water side, and the thinner the thickness between the two membrane sheets, meaning the flow channel becomes smaller. With a constant flow rate, a smaller flow channel results in a higher flow velocity, thus giving the concentrate a higher flow velocity, avoiding concentration polarization at the concentrate end, reducing fouling of the membrane surface, and increasing the membrane's lifespan.

[0064] Furthermore, existing membrane bags, due to their raw water guide nets, occupy a certain amount of space. In this application, the raw water guide net is only partially installed, allowing for the winding of longer membrane bags within the same radial space. This increases the usable membrane area for filtration, significantly improving water purification capacity.

[0065] A further improvement to the above embodiment is the sealing of the raw water side. Since the inner surface of membrane 1 has a separation layer that isolates salt or particulate matter in the water, applying adhesive to the inner surface would cause the separation layer to detach from the membrane's base layer, allowing concentrated water to permeate the membrane and affecting the membrane element's lifespan. Therefore, as a preferred solution, the membrane element in this embodiment can be sealed at both ends, for example, by applying adhesive to the ends; or by using end caps and applying adhesive between the end caps and the membrane end faces to achieve a seal on the end faces. For the pure water outlet or raw water inlet pre-reserved on the end faces, an annular unsealed area can be formed on the end faces as a water flow channel.

[0066] Figure 4 Another improvement to the inlet is demonstrated. A seal is formed on the inner side of the membrane 1 at the second short side 104, and a raw water inlet is provided on the second long side 102. This raw water inlet is located near one end of the second short side 104, forming an annular inlet at the center of the wound membrane element. Similarly, the first short side 103 serves as the concentrate outlet. On the pure water side, a pure water outlet can be formed using existing sealing methods, for example, at the second short side 104. In this scheme, raw water enters at the end of the membrane element, and the raw water is gradually filtered to form concentrate that flows out from the first short side 103. The pure water passing through the membrane 1 flows along the pure water side channel and out from the pure water outlet at the second short side 104. For example, a central tube can be incorporated, allowing the pure water to flow out from the central tube.

[0067] Figure 5Another improvement to the inlet is shown: a raw water inlet is set on the inner side of the diaphragm 1 near the middle of the second long side 102, and a raw water guide net 3 is set in the area between the raw water inlet and the second short side 104; the first short side 103 and the second short side 104 are both used as concentrated water outlets.

[0068] In this embodiment, since water enters from the middle, a raw water guide net 3 needs to be installed in the area between the raw water inlet and the second short side 104 to achieve pressure drop, forming a flow channel for inward flow. A concentrated water outlet is set at the second short side 104. Simultaneously, an adaptive flow channel can be used between the raw water inlet and the flow channel of the first short side 103, eliminating the need for the raw water guide net 3. Due to pressure, the filtered concentrated water can be discharged from the first short side 103. For the sealing structure on the raw water side, existing end-sealing methods can be used; there are no particular limitations as long as the corresponding water inlet method can be achieved.

[0069] In the above embodiments, the two membrane sheets 1 are independent membrane sheets, or a single membrane sheet is folded at the second short side 104 to form two membrane sheets 1, and the first long side 101 and the second long side 102 are sealed to form a seal on the raw water side. Of course, there may be only one membrane bag, or there may be multiple membrane bags, for example, 3, 4 or 5 membrane bags.

[0070] Figure 6 An embodiment of folding the membrane bag along its long side is shown.

[0071] In this design, the two membrane pieces 1 of the membrane bag are connected at the first long side 101 by a folded cornea 105, and the folded cornea 105 and the membrane piece 1 are an integral structure. Figure 6 , Figure 7 As shown, the large membrane is folded at the first long side 101 to form two membranes 1. On the raw water side, the first long side 101 does not need to be sealed; only the second long side 102 needs to be sealed as needed. On the pure water side, the entire first long side 101 forms a pure water outlet, shortening the pure water flow channel and making it more conducive to pure water output.

[0072] In a specific implementation structure, the second short side 104 can serve as the raw water inlet, and the first short side 103 as the concentrate outlet. The membrane element can have a central tube 2 with a guide hole 201 for raw water inlet. During operation, raw water enters the inner cavity from the end of the central tube 2, then enters the raw water inlet through the guide hole 201, and is discharged from the concentrate outlet on the first short side 103.

[0073] Of course, other water inlet methods mentioned above can also be used with this scheme, such as forming a water inlet on the second long side 102, which will not be elaborated further.

[0074] To ensure the membrane element has a better effect, as a further improvement, the thickness of the folded cornea 105 is 0.01 to 0.08 mm and the softness is 2.0 to 20.0 g, so that it can eliminate the folds formed at the first long side 101 when the membrane is rolled up.

[0075] Existing membranes are mostly thicker than 0.1 mm, which is quite large. If the long-side folding method of this application is adopted, the radial dimension of the wound membrane element is large at one end of the first long side, while the radial dimension is small at the other end because it is not folded, resulting in an overall conical structure. Using conventional membranes, after folding along the long side as described in this application, they still need to be wound along the long side through a central tube. During winding, the radial circumferences of the inner and outer sides of the membrane bag are different, resulting in displacement differences and forming noticeable wrinkles after winding. Due to the thickness, there are many sharp corners. These wrinkles and sharp corners can trap dirt and grime during filtration, leading to a shorter filter lifespan and even failure to meet standards.

[0076] In this application, to eliminate or reduce wrinkles caused by thickness and hardness, the membrane 1 used has a thickness of 0.01 to 0.08 mm. Within this thickness range, the flexibility is limited to 2.0 to 20 g, giving the reverse osmosis membrane good tensile and compressive deformation capabilities, thus eliminating wrinkles formed at the first long side during membrane roll-up and enabling normal filtration. Of course, as in other embodiments, the thickness can be further limited to 0.01 to 0.04 mm, and the flexibility can be limited to 2.2 to 15.0 g. This membrane can be a reverse osmosis membrane with the corresponding thickness, or a microfiltration, ultrafiltration, or nanofiltration water treatment membrane, enabling cross-flow filtration as described in this embodiment.

[0077] In this invention, the softness test is conducted using a Handle-O-Meter from Thwing-Albert Instrument Company. Its standard measurement range is 0-100g, and the weighted measurement range is 0-1000g. The unit "g" refers to the unit within the instrument's measurement range. The softness value in this application refers to the measured softness value. Measurements can be divided into transverse softness and longitudinal softness tests, with values ​​defined in this application as 2.0–20g. The softness of existing reverse osmosis membranes measured using this instrument is approximately 220–280g. Of course, other similar softness testers can also be used, with conversions between different units performed.

[0078] As a further limitation, in other embodiments, the stiffness of diaphragm 1 is 2.0–4.2 cm, and the surface of the wound membrane bag is a flat curved surface. The stiffness can be measured using the bending length testing method in the national standard GB / T 18318-2001. The length of the membrane bag along the first long side 101 can be greater than 1.0 m, for example, 2.0 m, 3.2 m, 4.5 m, etc. Currently, the length of diaphragms is generally less than 1 m, because a membrane that is too long will lead to insufficient pressure in the pure water flow channel. This application adopts a short flow channel structure, which increases the diaphragm length, forming a longer raw water flow channel, thereby increasing the flow rate and improving the antifouling ability.

[0079] Softer membrane materials can reduce the impact of wrinkles, but because the material itself is soft, its support strength is insufficient and it is easy to deform. Within a limited range of stiffness, the surface of the wound membrane element can be made to be a relatively flat curved surface, thus reducing wrinkles.

[0080] As a further embodiment, the thickness of membrane 1 is 0.01 to 0.04 mm, for example, 0.020 mm, 0.025 mm, or 0.032 mm. This membrane can be a polyolefin microporous membrane or the like. For example, a reverse osmosis polyolefin microporous membrane can be used, which can be formed by coating a filter material onto a thin base membrane; specific details can be found in existing membrane material processing techniques.

[0081] In some embodiments, the thickness of the raw water guiding net 110 can be 0.05–0.8 mm, for example 0.08 mm, 0.25 mm, or 0.50 mm; it can be further limited to 0.015–0.500 mm. In this embodiment, a relatively thin raw water guiding net 110 can be selected, which has a better matching effect with the membrane 1 and can avoid large deformation of the membrane 1.

[0082] In another embodiment of the membrane element, the membrane element includes a central tube 2 and a pure water flow guide cloth 4, which is disposed on the pure water side of the membrane bag to form a pure water flow channel. The pure water flow guide cloth 4 and the membrane bag are wound around the central tube 2 from the second short side 104.

[0083] In some implementations, such as those employing a folded cornea 105, as... Figure 7 In the scheme shown, the pure water guide cloth 4 can be connected to the central tube 2, and there is a certain distance between the membrane bag and the central tube to form a non-contact structure.

[0084] In one embodiment, the pure water guide cloth 4 can be connected to the central tube 2, the membrane bag is connected to the central tube, and wound to form a membrane element. The raw water guide net 3 surrounds the central tube 2 at least 3 / 4 of its circumference in the circumferential direction. Setting a certain length of raw water guide net 3 can, on the one hand, have a good guiding effect on the raw water, and on the other hand, can form a certain length of support in the axial direction, avoiding the impact on membrane performance due to a significant height difference caused by the loss of the raw water guide net 3.

[0085] Figure 8 A sealing method for the pure water side is also demonstrated. Adhesive strips 120 are affixed to the first short side 103, the second short side 104, and the second long side 102 on the pure water side of the membrane bag, forming a U-shaped sealing structure. This seal is achieved by attaching the adhesive strips 120 to the pure water side of the membrane bag. After winding, the adhesive strips 120 and the surface of the pure water side of the membrane bag form a closed area, isolating it from the raw water and concentrate. Furthermore, the adhesive strips may include a main adhesive strip 121 and a side adhesive strip 122. The main adhesive strip 121 is used for short-side sealing, and the side adhesive strips 122 seal the area between the main adhesive strip 121 and the central tube 2. On the raw water side of the membrane bag, the raw water can flow circumferentially after entering. The specific water inlet and outlet methods can refer to the existing water inlet and outlet methods of membrane elements. During water purification, after the raw water enters, the pure water permeates through the membrane 1 and flows towards the first long side 101, exiting from the end face where the first long side 101 of the membrane element is located. To facilitate the installation of a pure water flow path after sealing, the side rubber strip 122 can be made to extend beyond the main rubber strip 121 in the length direction.

[0086] In this embodiment, the length of the membrane bag along the first long side 101 is further limited, and can be 1.0 to 4.6 m. In this embodiment, due to the use of a short flow channel structure, the pure water flow is not affected by the length of the membrane bag. A longer membrane element can be used, and by lengthening the raw water flow channel, the flow velocity on the raw water side can be increased, avoiding the formation of sediment.

[0087] Based on the aforementioned foldable membrane properties, in other embodiments, such as Figure 9a In the illustrated scheme, both sides of the folded cornea 105 are connected to the membrane 1 via adhesive bonding. During connection, the folded side of the cornea 105 is bonded to the outer side of the membrane 1 using adhesive. Alternatively, it can be connected via membrane welding. It can also be as follows... Figure 9b The folded edge connection in the middle.

[0088] Because of its structure and performance, the folded cornea 105 can maintain the performance of the membrane element even after folding. This folded cornea 105 can be combined with existing, relatively thick membrane materials through adhesive bonding or thin-film welding to form a membrane element with good performance. Adhesive bonding can be achieved by using adhesive strips, and thin-film welding can employ existing known welding methods such as laser thin-film welding or heat welding.

[0089] As another embodiment of the membrane element, it includes a membrane element and a central tube 2. The membrane element is wound on the central tube 2. The membrane element includes at least one membrane bag with opposing first long sides 101 and second long sides 102, and opposing first short sides 103 and second short sides 104. After winding, the second short side 104 is located in the innermost layer, and the first short side 103 is located in the outermost layer.

[0090] A raw water guide net 3 is disposed on the inner side of the membrane 1; each membrane bag has two opposing membranes 1, the inner side of the membrane 1 forms a raw water flow channel, which connects the raw water inlet and the concentrate outlet of the membrane bag; the outer side of the membrane 1 forms a pure water flow channel. The raw water guide net 3 is approximately equal to the second short side 104 in the width direction, and is partially disposed in the length direction, covering the raw water inlet area; during operation, the pressure difference between the raw water inlet and the concentrate outlet causes a portion of the area between the two membranes 1 to be opened by the water flow, forming an adaptive flow channel area. Under certain winding support conditions, the second short side 104 can be set as the concentrate outlet. This implementation requires the use of a membrane with high flexibility and control of the pressure range to avoid internal membrane compression leading to poor water flow and membrane damage.

[0091] The present invention also provides a filter element, wherein the membrane element used in the above embodiments is the membrane element in each of the embodiments, or a membrane element combining the parts of different embodiments.

[0092] As a specific implementation method, combined with Figure 10 The central tube 2 of the membrane element is parallel to the second short side 104 of the membrane bag. The membrane element is wound around the central tube 2 from the second short side 104 side. The end where the first long side 101 is located is the pure water outlet. Raw water enters the membrane bag along the raw water guide net 110, and the filtered pure water flows out from the pure water outlet along the pure water guide cloth 4. The filter element also includes a first end cap 51 and a second end cap 52. The first end cap 51 is installed at one end of the first long side 101, and there is a certain gap between the inner end face of the first end cap 51 and the first long side 101 to form a pure water collection chamber 501. The second end cap 52 is installed at one end of the second long side 102, and at least partially, adhesive is provided on the inner end face of the second end cap 52 to form a seal with the end face of the membrane element. A Y-shaped sealing ring can also be provided at one end to define the water channel structure.

[0093] Furthermore, in one embodiment, a raw water inlet is provided on the side of the second long side 102 near the central tube 2, and a concentrated water outlet is provided on the first short side 103, so that one end of the filter element is the raw water inlet and the other end is the pure water outlet. In the above embodiments, the inlet and outlet ends refer more to the membrane element and are ultimately formed on the complete filter element housing structure. Whether they are located at the same end or at two ends can be improved by using the central tube or other water passages inside the housing.

[0094] In some of the above embodiments, when the central pipe 2 is not used for water inlet or outlet, the central pipe 2 may only serve a supporting function and does not have a water channel structure. In other embodiments, the central pipe 2 may be a hollow structure, forming a water flow cavity, used as a water channel for raw water, pure water, or concentrated water.

[0095] Compared to existing filter cartridges, this design reduces the length of the raw water guide filter screen per membrane bag while using the same membrane housing size. Within the same radial dimension range, longer membrane bags can be installed, increasing the membrane area for water purification and improving purification capacity. In the adaptive flow channel, the water flow thickness between two membrane sheets is reduced, thereby increasing the flow rate and avoiding the problem of increased water concentration affecting the flow rate, thus extending service life.

[0096] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A raw water localized flow guiding membrane element for cross-flow filtration; comprising: At least one film bag, the film bag having a first long side (101) and a second long side (102) opposite each other, and a first short side (103) and a second short side (104) opposite each other, the first short side (103) being located on the outermost layer after the film is rolled up; The raw water diversion net (3) is set on the inner side of the diaphragm (1); Its features are: Each membrane bag has two opposing membrane sheets (1). The inner side of the membrane sheet (1) forms a raw water flow channel, which connects the raw water inlet and the concentrate outlet of the membrane bag, and the concentrate outlet is located at the first short side (103); the outer side of the membrane sheet (1) forms a pure water flow channel. The raw water diversion net (3) is approximately equal to the second short side (104) in the width direction, and the raw water diversion net (3) is partially set in the length direction, and the raw water diversion net (3) covers the raw water inlet area; the area not covered by the raw water diversion net (3) automatically forms a water flow channel by utilizing the pressure difference.

2. The raw water local flow guiding membrane element according to claim 1, characterized in that: On the inner side of the membrane (1), the raw water inlet is located at the second short side (104), and a seal is formed at the first long side (101) and the second long side (102), so that the water flows into the membrane bag from the second short side (104) and is discharged from the first short side (103).

3. The raw water local flow guiding membrane element according to claim 1, characterized in that: The membrane (1) is closed at the second short side (104) on the inner side, and a raw water inlet is provided on the first long side (101) or the second long side (102), which is close to one end of the second short side (104).

4. The raw water local flow guiding membrane element according to claim 1, characterized in that: On the inner side of the membrane (1), a raw water inlet is provided near the middle of the first long side (101) or the second long side (102), and a raw water guide net (3) is provided in the area between the raw water inlet and the second short side (104); the first short side (103) and the second short side (104) are both used as concentrated water outlets.

5. A raw water local flow guiding membrane element according to any one of claims 2 to 4, characterized in that: A pure water outlet is provided on the outer side of the diaphragm (1) at a local position on the first long side (101) or the second long side (102), or a pure water outlet is provided on the second short side (104).

6. A raw water local flow guiding membrane element according to any one of claims 2 to 4, characterized in that: The two membranes (1) of the membrane bag are connected at the first long side (101) by a folded cornea (105), and the folded cornea (105) and the membrane (1) are an integral structure; Alternatively: one side of the folded cornea (105) is integral with the membrane (1), and the other side is connected to the membrane (1) by adhesive bonding or thin film welding. Alternatively: Both sides of the folded cornea (105) are connected to the membrane (1) by adhesive bonding or thin film welding.

7. The raw water local flow guiding membrane element according to claim 6, characterized in that: The folded cornea (105) has a thickness of 0.01~0.08mm and a softness of 2.0~20.0g, which enables it to eliminate the folds formed at the first long side (101) during the roll-up process.

8. The raw water local flow guiding membrane element according to claim 7, characterized in that: On the pure water side of the membrane bag, a seal is formed at least near the first short side (103), the second short side (104), and the second long side (102), so that the filtered pure water flows out from the end where the first long side (101) is located.

9. The raw water local flow guiding membrane element according to claim 1, characterized in that: It also includes a central tube (2) and a pure water flow guide cloth (4), which is disposed on one side of the membrane bag. The pure water flow guide cloth (4) and the membrane bag are wound around the central tube (2) from the second short side (104).

10. A raw water local flow guiding membrane element according to claim 9, characterized in that: The raw water diversion network (3) surrounds the central pipe (2) at least 3 / 4 of its circumference in the circumferential direction.

11. A raw water local flow guiding membrane element, comprising a central tube (2). At least one film bag having opposing first long sides (101) and second long sides (102), and opposing first short sides (103) and second short sides (104), the film bag being wound around the central tube (2) from the second short side (104); after winding, the second short side (104) is located in the innermost layer, and the first short side (103) is located in the outermost layer; The raw water diversion net (3) is set on the inner side of the diaphragm (1); Its features are: Each membrane bag has two opposing membrane sheets (1). The inner side of the membrane sheet (1) forms a raw water channel, which connects the raw water inlet and the concentrate outlet of the membrane bag; the outer side of the membrane sheet (1) forms a pure water channel. The raw water guide net (3) is approximately equal to the second short side (104) in the width direction, and the raw water guide net (3) is partially set in the length direction, and the raw water guide net (3) covers the raw water inlet area; when working, the pressure difference between the raw water inlet and the concentrate outlet causes a part of the area between the two membranes (1) to be opened by the water flow, forming an adaptive flow channel area.

12. The raw water local flow guiding membrane element according to claim 11, characterized in that: The raw water inlet is located on the side close to the central pipe (2), and the concentrated water outlet is located at the first short side (103).

13. The raw water local flow guiding membrane element according to claim 11, characterized in that: The membrane (1) has a certain deformation capability. Under water pressure, it can deform to form a flow channel, and the surface of the membrane element is a flat curved surface.

14. A filter element, characterized in that: The membrane element includes any one of claims 1-13, wherein the membrane element has an end cap at at least one end and an end cap or Y-shaped sealing ring at the other end.

15. A filter element according to claim 14, characterized in that: It also includes a membrane housing, in which the membrane element is installed, and there is a gap between the inner wall of the membrane housing and the membrane element for the discharge of concentrate.

Images