Short channel membrane element and filter cartridge

Abstract

The application discloses a short-flow-path membrane element and a filter core, and belongs to the technical field of water purification. The short-flow-path membrane element comprises a membrane bag, the membrane bag has opposite first and second long edges and opposite first and second short edges, and the membrane bag is wound along the first long edge extension direction to form a membrane element; the membrane bag is formed by folding a thin base film sheet along the first long edge, the thickness of the thin base film sheet is 0.005-0.08 mm, and the softness is 2.0-10 g, so that the thin base film sheet can form a wrinkle at the first long edge when being wound; during filtration, water flows into a raw water side, pure water formed by passing through the thin base film sheet flows out from the first long edge side along a pure water flow path, and concentrated water remaining in the raw water side is discharged from the first short edge and / or the second short edge along a raw water flow path. The pure water side flow path of the membrane element is shortened, the pure water production efficiency is improved, and the membrane element has a relatively long service life.

Description

Technical Field

[0001] This invention relates to the field of water purification technology, and more specifically, to a short-channel membrane element and filter cartridge. Background Technology

[0002] With increasing attention to health issues, drinking water quality is receiving more and more attention, and water purifiers are gradually becoming necessities for every household. For water purifiers, the filter cartridge is a crucial component for water filtration. It generally includes a base membrane that can be rolled into a filter cartridge, and raw water channels and pure water channels located on opposite sides of the base membrane. During use, raw water flows into the raw water channel through the inlet, then passes through the membrane to become pure water, which enters the pure water channel. Impurities are filtered out through the reverse osmosis effect of the membrane, resulting in the pure water that people need.

[0003] 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.

[0004] Combination Figure 1 In the filter element solution disclosed in patent CN201810506458.2, the thickness of the raw water guide net and the product water guide net in the spiral wound membrane element is set to be gradient distributed along the direction from the raw water inlet end to the concentrate outlet end, thereby increasing the linear velocity of the concentrate outlet and making the membrane element less prone to clogging. This solution increases the water flow rate by reducing the thickness of the guide net, but in actual manufacturing, it is difficult to achieve a gradual thickness for the inlet guide net.

[0005] exist Figure 2 The illustrated solution is a scheme disclosed in patent CN201120187959.2. In this solution, the reverse osmosis membrane is folded to form three folds on the side of the central tube. The middle fold extends into the feed channel, dividing the feed channel into upper and lower forward feed channels on the side of the central tube and a rear feed channel on the side of the concentrate outlet. The feed guide net is divided into a large feed guide net and a small feed guide net. The large feed guide net is placed in one of the forward and rear feed channels, while the small feed guide net is placed only in the other forward feed channel. This patent essentially increases the feed flow rate by increasing the thickness on the feed side, and then uses the thickness difference to increase the flow velocity at the end of the raw water supply.

[0006] While the above solutions alter the flow rate on the raw water side, the pure water flow channel is relatively long. The pressure loss of the pure water formed through the reverse osmosis membrane is significant, and a longer flow channel greatly reduces the water flow rate, making it difficult to increase the amount of purified water per unit time. To address this issue, patent CN205095658U discloses a membrane element with a short flow channel. This design forms a sealing section on one long side, allowing raw water to flow out from the end. While this solution appears to achieve a short flow channel for pure water, in actual membrane winding, the radial difference between the inner and outer membrane sheets at the sealing section causes numerous wrinkles at that end, and the entire wound filter element exhibits a conical structure, making it practically impossible to implement. Summary of the Invention

[0007] 1. The technical problem that the invention aims to solve

[0008] The purpose of this invention is to overcome the shortcomings of existing reverse osmosis membrane elements in achieving short flow channels and high flow rates of pure water, and to provide a short-flow-channel membrane element and filter cartridge. This solution enables the pure water produced by the membrane element to flow out rapidly from the end through a shorter flow channel, thereby improving water purification efficiency.

[0009] 2. Technical Solution

[0010] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0011] A short-channel membrane element of the present invention includes a membrane bag having opposing first long side and second long side, and opposing first short side and second short side, the membrane bag being wound along the extending direction of the first long side to form a membrane element;

[0012] The membrane bag is formed by folding a thin base membrane sheet along the first long side. The inner side of the membrane bag is the raw water side, and the outer side is the pure water side. During filtration, water flows into the raw water side, and the pure water formed by passing through the thin base membrane sheet flows out from the first long side along the pure water channel. The remaining concentrated water on the raw water side is discharged from the concentrated water outlet along the raw water channel.

[0013] The thickness of the thin base film is 0.005 to 0.08 mm, and the softness is 2.0 to 10 g, which enables it to eliminate wrinkles formed at the first long side during film rolling.

[0014] Furthermore, the stiffness of the thin base film is 2.0 to 4.2 cm, and the surface of the rolled film bag is a flat curved surface.

[0015] Furthermore, the thickness of the thin substrate film is 0.01 to 0.04 mm.

[0016] Furthermore, on the pure water side of the membrane bag, a seal is formed at least on the first short side, the second short side, and the second long side, so that pure water passing through the thin base membrane flows towards the first long side, and pure water flows out from the end face where the first long side of the membrane element is located.

[0017] Furthermore, a seal is formed at the second long side of the membrane bag on the raw water side, with one side of the first short side or the second short side serving as the raw water inlet and the other side serving as the concentrate outlet.

[0018] Furthermore, on the raw water side of the membrane bag, the second long side is partially sealed, so that a raw water inlet is formed near the middle of the second long side, and the first short side and / or the second short side serves as a concentrate outlet.

[0019] Furthermore, on the raw water side of the membrane bag, one of the first short side or the second short side is a sealed side, and the other short side forms a concentrate outlet; the second long side is partially sealed, so that a raw water inlet is reserved at one end of the second long side near the sealed side.

[0020] Furthermore, the membrane bag is provided with a raw water guide net on the raw water side. The raw water guide net is basically the same size as the membrane bag in the width direction; in the length direction, the raw water guide net is used to form a raw water flow channel.

[0021] Furthermore, the membrane element is provided with a pure water flow guide cloth, which is disposed on the pure water side of the membrane bag to form a pure water flow channel.

[0022] Furthermore, the length of the membrane bag along the first long side is 1.0 to 4.6 m.

[0023] The present invention provides a short-channel membrane element having at least two membrane bags, wherein the membrane bags adopt the membrane bag structure described above, and a pure water guide cloth is provided between adjacent membrane bags.

[0024] Furthermore, at least two of the membrane bags are integral structures, formed by folding a thin base membrane along the first long side and then folding it a second time along the second short side; or:

[0025] At least two of the membrane bags are an integral structure, formed by folding a thin base membrane along the first long side and then folding it a second time along the second long side to form an M-shaped structure.

[0026] The present invention provides a filter element comprising the aforementioned membrane element.

[0027] Furthermore, the filter element includes a central tube, which is parallel to the second short side of the membrane bag. The membrane element is wound around the central tube from the second short side, and the end where the first long side is located is the pure water outlet. Raw water enters the membrane bag along the raw water guide net, and the filtered pure water flows out from the pure water outlet along the pure water guide cloth.

[0028] Furthermore, a raw water inlet is provided on the side of the second long side near the central tube, and the first short side is the raw water outlet, so that one end of the filter element is the raw water inlet and the other end is the pure water outlet.

[0029] Furthermore, the pure water guide cloth is connected to the central tube, and the second short side of the membrane bag is in a non-contact state with the central tube; and the area between the second short side and the central tube is sealed at the pure water outlet to isolate the raw water.

[0030] Furthermore, the central tube has a hollow structure, forming a water flow cavity, which is used as a water flow channel for raw water, pure water, or concentrated water.

[0031] Furthermore, the central tube protrudes axially from the first long side and has a guide hole at the protruding position. A cavity is provided at the pure water outlet end, which is connected to the guide hole, so that the pure water connector and the raw water connector connected to the outside are located at the same end of the filter element.

[0032] Furthermore, the outer shell of the filter element has a secondary flow channel, and a cavity is provided at the pure water outlet. One end of the secondary flow channel is connected to the cavity at the pure water outlet, and the other end is connected to the pure water connector, so that the pure water connector and the raw water connector connected to the outside are located at the same end of the filter element.

[0033] A filter element of the present invention includes a central tube and the aforementioned membrane element, wherein the central tube is parallel to the short side of the membrane bag, and at least one membrane element is wound on the central tube; during winding, the membrane bag is wound on the central tube by stretching and tensioning, so that the surface of the membrane bag is a flat curved surface.

[0034] Furthermore, the thickness of the thin base film is 0.01 to 0.03 mm, the softness is 2.2 to 5.0 g, and the stiffness is 2.5 to 4.0 cm.

[0035] 3. Beneficial effects

[0036] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0037] The short-channel membrane element of the present invention has a membrane bag formed by folding a thin base membrane sheet along the first long side and winding it along the extension direction of the first long side to form the membrane element, thereby shortening the pure water side channel and improving the pure water production efficiency. In addition, by limiting the thickness and flexibility of the thin base membrane sheet within a certain range, it can eliminate the wrinkles formed at the first long side during membrane winding, ensuring that the membrane element of this folding scheme can have a longer service life. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a pure water flow channel in the prior art;

[0039] Figure 2 This is a schematic diagram of the short-side folding and winding method in the prior art;

[0040] Figure 3 This is a schematic diagram of one folding method for the film bag of this application;

[0041] Figure 4 This is a schematic diagram of the unfolded structure of a membrane bag according to this application;

[0042] Figure 5 This is a schematic diagram illustrating the deformation principle of the folded edge when the diaphragm is folded.

[0043] Figure 6 This is a schematic diagram of the winding effect after folding the long side of an existing diaphragm.

[0044] Figure 7 This is a schematic diagram illustrating the winding effect of the membrane after its long side is folded.

[0045] Figure 8 This is a schematic diagram of the unfolded structure of a membrane element according to this application;

[0046] Figure 9a A schematic diagram of a sealing method for the pure water side of a membrane element;

[0047] Figure 9b This is a schematic diagram of another sealing method for the pure water side of a membrane element;

[0048] Figure 10a This is a schematic diagram of the short-side water inlet and outlet configuration of a membrane element.

[0049] Figure 10b This is a schematic diagram of another embodiment of the membrane element with water inlet and outlet along the short side;

[0050] Figure 10c A schematic diagram of one embodiment where water enters and exits at the middle position of the membrane element;

[0051] Figure 10d A schematic diagram of one embodiment of a membrane element with water inlet at the end and water outlet at the short side;

[0052] Figure 10e for Figure 10d A schematic diagram of the structure of the winding intermediate membrane element;

[0053] Figure 11 A schematic diagram of a membrane element structure with a short-side double folding configuration;

[0054] Figure 12 A schematic diagram of a filter element that outputs pure water at the end;

[0055] Figure 13 This is a schematic diagram of a filter cartridge that guides pure water through a central tube.

[0056] Explanation of the labels in the diagram:

[0057] 01. Raw water flow channel; 02. Pure water flow channel;

[0058] 1. Membrane bag; 100. Thin base membrane sheet; 100a. Membrane A; 100b. Membrane B; 101. First long side; 102. Second long side; 103. First short side; 104. Second short side;

[0059] 110. Raw water diversion net; 120. Rubber strip; 121. Main rubber strip; 122. Side rubber strip;

[0060] 2. Central tube;

[0061] 3. Pure water diversion cloth. Detailed Implementation

[0062] 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.

[0063] 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.

[0064] 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. Therefore, this application presents a short-channel membrane element.

[0065] Combination Figure 3 , Figure 4This embodiment of a short-channel membrane element includes a membrane bag 1, which 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 1 is wound along the extending direction of the first long side 101 to form a membrane element. For example, a central tube can be placed parallel to the second short side 104 to form a membrane element with a central tube by winding it along the extending direction of the first long side 101. To clearly illustrate the structure of the membrane element, this embodiment will describe it in conjunction with the unfolded or wound state of the membrane element to clearly demonstrate the structure of the membrane element. Therefore, the membrane element is not limited to an unfolded or wound state. When used as part of a filter element, a wound state is required.

[0066] The membrane bag 1 is formed by folding a thin base membrane 100 along its first long side 101, dividing the thin base membrane 100 into membrane A 100a and membrane B 100b. The inner surfaces of the membrane bag 1 facing each other are the raw water side, and the outer surfaces are the pure water side. That is, the side facing each other of membrane A 100a and membrane B 100b is the raw water side, and the outer surfaces facing away from each other are the pure water side.

[0067] The wound membrane element has a multi-layer wound structure. On the raw water side, a raw water channel 01 is formed, allowing raw water to flow circumferentially around the filter element from the inner layer to the outer layer or from the outer layer to the inner layer. On the pure water side, an axial pure water channel 02 is formed. During filtration, water flows into the raw water side, and the pure water formed by passing through the thin base membrane 100 flows out from the first long side 101 along the pure water channel 02. The remaining concentrated water on the raw water side is discharged from the concentrated water outlet along the raw water channel 01, for example, from the first short side 103 or the second short side 104, or simultaneously from both the first short side 103 and the second short side 104.

[0068] It is worth noting that in this embodiment, the thickness of the thin base membrane 100 is 0.005 to 0.08 mm and the softness is 2.0 to 10 g, which enables it to eliminate the wrinkles formed at the first long side 101 during membrane winding and to perform normal filtration.

[0069] 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. However, when folding the short side, the dimensions accumulated during folding are in the axial direction, and multiple folded edges can be evenly distributed, resulting in a membrane element with a more consistent radial dimension.

[0070] Figure 5The diagram illustrates a folding principle using a thin film of thickness d. After folding, the inner and outer edges at the fold point essentially rotate approximately 180° around the fold line. Due to the thickness d, the rotation circumferences of the inner and outer sides of the film differ during folding. As shown at point C1 in the diagram, the inner side rotates nearly 180° while the outer side's rotation tangential angle may only be around 90°. This results in a greater tensile deformation on the outer side and a tensile resistance to compression on the inner side after folding. If the film is stiff, a permanent crease will form after folding, indicating damage to its internal structure.

[0071] Furthermore, when using conventional membranes folded along the long side as described in this application, they are then wound along the long side through a central tube. During winding, the radial circumferences of the inner and outer sides of the membrane bag differ, resulting in a displacement difference and thus creating noticeable wrinkles after winding. For example... Figure 6 As shown, due to its thickness, there are many sharp corners. These wrinkles and sharp corners can trap dirt and grime during filtration, resulting in a shorter filter lifespan and even failure to meet standards.

[0072] In this application, to eliminate or reduce wrinkles caused by thickness and hardness, the thickness of the thin-based membrane sheet 100 is 0.005–0.08 mm. Within this thickness range, the flexibility is limited to 2.0–10 g, giving the reverse osmosis membrane good tensile and compressive deformation capabilities, thus eliminating wrinkles formed at the first long side during membrane winding and enabling normal filtration. Of course, as in other embodiments, the thickness can be further limited to 0.018–0.050 mm, and the flexibility can be limited to 2.3–6.0 g. This thin-based membrane sheet can be a reverse osmosis membrane sheet with the corresponding thickness, or a microfiltration, ultrafiltration, or nanofiltration water treatment membrane, enabling cross-flow filtration as described in this embodiment.

[0073] The softness testing method in this invention is based on standard EDANA WSP 90.3, and the test is conducted using a Handle-O-Meter softness meter from Thwing-Albert Instrument Company. Its standard measurement range is 0-100g, and the weighted measurement range is 0-1000g. The unit used, g, is the unit within the instrument's measurement range. The softness in this application refers to the measured and displayed softness value. Measurement can be divided into transverse softness testing and longitudinal softness testing, with values ​​defined in this application as 2.0–10g. Softness measured using other instruments can be converted according to the unit.

[0074] As a further limitation, in other embodiments, the stiffness of the thin base film 100 is 2.0–4.2 cm, and the surface of the wound film bag 1 is a flat curved surface. The stiffness here can be tested using the bending length testing method in the national standard GB / T 18318-2001. The length of the film bag 1 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.

[0075] 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.

[0076] Figure 7 This is a schematic diagram of the winding effect of the reverse osmosis membrane with a certain degree of flexibility and rigidity used in this application. The long sides of the different layers are staggered so that it can be observed that there are no obvious wrinkles after the folds and overlaps of the different layers are wound, and sharp corners formed due to force transmission are eliminated.

[0077] As a further embodiment, the thickness of the thin base membrane 100 is 0.01 to 0.04 mm, for example, 0.020 mm, 0.025 mm, or 0.032 mm. This membrane can be a membrane formed from a polyolefin microporous membrane, etc. For example, a reverse osmosis polyolefin microporous membrane can be used, which can be formed by coating a filter material onto a relatively thin base membrane; specific details can be found in existing membrane material processing techniques.

[0078] Figure 9 illustrates another embodiment of the membrane element. In this embodiment, a raw water guide net 110 is provided on the raw water side of the membrane bag 1. The raw water guide net 110 is substantially the same size as the membrane bag 1 in both the width and length directions. In the length direction, the raw water guide net 110 can at least be connected to the raw water inlet to guide the raw water into the membrane bag 1.

[0079] In membrane bag 1, on the side of the first long side 101, due to the folding of the membrane, the raw water guiding net 110 can only be placed on the inside, and its width cannot be flush with the side of the first long side 101. On the side of the second long side 102, the raw water guiding net 110 can be flush with the second long side 102. In addition, by controlling the width of the raw water guiding net 110, it is also possible to ensure that a conical structure does not appear during membrane winding.

[0080] The thickness of the raw water diversion 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 diversion net 110 can be selected, which has a better matching effect with the thin-based membrane 100 and can avoid large deformation of the thin-based membrane 100.

[0081] In the length direction, the raw water diversion net 110 can be equal to or greater than the length of the membrane bag 1, to facilitate water intake.

[0082] Furthermore, preferably, the membrane element is provided with a pure water guiding cloth 3, which is disposed on the pure water side of the membrane bag 1 to form a pure water flow channel. In one embodiment, the pure water guiding cloth 3 can be connected to the central tube 2, and the membrane bag 1 is connected to the central tube and wound to form a membrane element. In another embodiment, the pure water guiding cloth 3 can be connected to the central tube 2, and there is a certain distance between the membrane bag 1 and the central tube, forming a non-contact structure.

[0083] Based on the above embodiments, the membrane element inlet and outlet structure of this application can have a variety of specific embodiments.

[0084] Figure 9a A sealing method for the pure water side is demonstrated. On the pure water side of the membrane bag 1, a seal is formed at least on the first short side 103, the second short side 104, and the second long side 102. This seal is achieved by attaching an adhesive strip 120 to the pure water side of the membrane bag 1. After being rolled up, the adhesive strip 120 and the surface of the pure water side of the membrane bag 1 form a closed area, which can isolate it from the raw water and concentrate. On the raw water side of the membrane bag 1, the raw water can flow circumferentially after entering. The specific water inlet and outlet methods can refer to the water inlet and outlet methods of existing membrane elements. During water purification, after the raw water enters, the pure water flows through the thin base membrane 100 towards the first long side 101, and the pure water flows out from the end face where the first long side 101 of the membrane element is located.

[0085] Figure 9b This demonstrates another sealing method on the pure water side. Figure 9a Based on this, this embodiment can include more rubber strips 120 parallel to the short side. As shown in the figure, the two additional rubber strips divide the pure water flow channel into multiple zones, providing a certain degree of flow guidance and stabilization.

[0086] Regarding the raw water intake method, Figure 10a The image illustrates a method in which raw water enters from the central pipe 2 and flows out through a hole in the central pipe, entering the raw water channel. In this embodiment, a seal is formed at the second long side 102 of the membrane bag 1, the second short side 104 serves as the raw water inlet, and the side where the first short side 103 is located serves as the concentrate outlet.

[0087] It is worth noting that in this embodiment, the main adhesive strip 121 on the pure water side, near the second short side 104, is a certain distance from the second short side 104. This distance is sufficient to isolate the raw water from the pure water side circumferentially. Furthermore, the area between the main adhesive strip 120 and the central tube 2 is sealed by a side adhesive strip 122, which is located near the first long side 101, ensuring that the pure water and raw water at the end are also sealed. Of course, as another sealing method, sealing can be achieved by applying adhesive to the central ring at the end of the wound membrane element instead of the side adhesive strip 122, or by combining multiple sealing methods.

[0088] Correspondingly, the same method can be used to isolate pure water from concentrated water at the concentrate outlet, which can be achieved by sealing the membrane bag with adhesive strips and applying glue to the outer ring at the end.

[0089] Figure 10b This demonstrates another water intake method, which is different from... Figure 10a The directions of raw water inlet and concentrated water outlet are opposite, that is, the side where the first short side 103 is located is the raw water inlet side, and the side where the second short side 104 is located is the concentrated water outlet side. The sealing method can refer to the aforementioned implementation method.

[0090] Figure 10c The paper demonstrates an implementation scheme for intermediate water intake on the raw water side.

[0091] exist Figure 10c In the proposed scheme, an inlet is provided in the middle of the membrane bag 1. On the raw water side of the membrane bag 1, the second long side 102 is partially sealed, so that a raw water inlet is formed near the middle of the second long side 102. The first short side 103 and / or the second short side 104 serve as the concentrate outlet.

[0092] Since the raw water inlet is formed at the middle of the second long side 102, a partial seal is formed on both sides of the raw water inlet. This seal can be achieved by applying adhesive strips or by sealing the end face with the filter element end cap. This embodiment focuses on illustrating the water inlet method; the sealing method can adopt any existing technology that can be implemented and is not specifically limited. The middle position of the second long side 102 does not need to be the geometric center of the second long side 102; it can also be close to either the first short side 103 or the second short side 104.

[0093] exist Figure 10c In the scheme, after the raw water enters from the inlet at the middle of the second long side 102, due to the water pressure, the raw water will flow simultaneously towards the first short side 103 and the second short side 104. Through the flow channel setting, the filtered concentrate can flow from the gap between the central tube and the membrane element and the filter cartridge housing to the external concentrate outlet.

[0094] Figure 10d An embodiment with water inlet at one end and water outlet on one side is shown.

[0095] Figure 10d In the implementation scheme, on the raw water side of the membrane bag 1, the second short side 104 is a sealing side, which can be sealed by a rubber strip. The first short side 103 forms a concentrate outlet; the second long side 102 is partially sealed, so that a raw water inlet is reserved at the end of the second long side 102 near the second short side 104.

[0096] In this embodiment, the central tube does not serve as the raw water channel, but rather forms a raw water inlet at its end opening, with the first short side 103 serving as the concentrate outlet. In this membrane element, one end is the raw water inlet, and the other end is the pure water outlet. This is reflected in the wound membrane element, such as... Figure 10e As shown.

[0097] In conjunction with the above embodiments, the length of the membrane bag 1 along the first long side 101 is further limited in this embodiment, and can be 1.0 to 4.6 m. Currently, conventional membrane elements are generally limited to less than 0.8 m due to the constraints of the pure water flow channel, to avoid forming a long flow channel. In the solution of this invention, 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; by lengthening the raw water flow channel, the flow velocity on the raw water side can be increased, avoiding sedimentation.

[0098] Based on the corresponding structures of the membrane elements and membrane bags in the above embodiments, as other embodiments of the membrane element of the present invention, at least two membrane bags 1 can be provided in the membrane element, for example, three or four membrane bags are used, and a pure water guide cloth 3 is provided between adjacent membrane bags 1.

[0099] Figure 11 This demonstrates another approach to membrane element design, where the two membrane bags 1 are an integral structure, formed by folding a thin base membrane sheet 100 along the first long side 101 and then folding it a second time along the second short side 104. When four membrane bags 1 are used, the two membrane bags 1 with the integral structure form a group, and the four membrane bags can be divided into two groups to constitute one membrane element. When an odd number of membrane bags are used, one of the membrane bags can be a separate membrane bag structure.

[0100] In addition, as another integrated structural form, at least two of the membrane bags 1 are integrated structures, formed by folding a thin base membrane 100 along the first long side 101 and then folding it a second time along the second long side 101 to form an M-shaped structure. In this case, the second long side 101 connecting the two membrane bags is a common long side.

[0101] 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.

[0102] As a specific way of explaining, such as Figure 12 As shown, the filter element includes a central tube 2, and a membrane element is wound around the central tube 2. The central tube 2 is parallel to the second short side 104 of the membrane bag 1. The membrane element is wound around the central tube 2 from the side of the second short side 104. The end where the first long side 101 is located is the pure water outlet. Raw water enters the membrane bag 1 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 3.

[0103] 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.

[0104] As one feasible approach, the pure water guide cloth 3 is connected to the central tube 2, and the second short side 104 of the membrane bag 1 is in a non-contact state with the central tube 2; and the area between the second short side 104 and the central tube 2 is sealed at the pure water outlet to isolate the raw water.

[0105] In the above methods, when the central pipe 2 is not used for water inlet or outlet, the central pipe 2 can simply serve a supporting function and does not have a water channel structure. As another implementation method, the central pipe 2 can be a hollow structure to form a water flow cavity, which is used as a water channel for raw water, pure water, or concentrated water.

[0106] Figure 13 An implementation method using a central pipe as the pure water flow path is demonstrated.

[0107] exist Figure 13 In the presented design, the central tube 2 protrudes axially from the first long side 101 and has a guide hole at the protruding position. A cavity is provided at the pure water outlet end, which is connected to the guide hole, so that the pure water connector and the raw water connector connected to the outside are located at the same end of the filter element.

[0108] In this embodiment, the guide hole can be a central hole at the end of the central tube or a through hole opened on the side wall of the central tube.

[0109] In other embodiments, a secondary flow channel can be formed in the outer shell of the filter element, and a cavity can be provided at the pure water outlet. One end of the secondary flow channel is connected to the cavity at the pure water outlet, and the other end is connected to the pure water connector, so that the pure water connector and the raw water connector connected to the outside are located at the same end of the filter element.

[0110] Alternatively, the central tube can be configured as a tube structure with concentric rings, forming a central cavity and an outer ring cavity, both axially oriented. The outer ring cavity can serve as the raw water inlet cavity, allowing raw water to be introduced through perforated membrane elements on the tube wall, while the central cavity serves as the pure water flow channel. Other flow patterns can also be used in this configuration without specific limitations.

[0111] As a filter element of the present invention, it includes a central tube 2 and a membrane element wound on the central tube. The central tube 2 is parallel to the short side of the membrane bag 1, and at least one membrane element is wound on the central tube 2. During winding, the membrane bag 1 is wound on the central tube 2 by stretching and tensioning, so that the surface of the membrane bag 1 is a flat curved surface.

[0112] Specifically, the membrane element has a membrane bag 1 with opposing first long sides 101 and second long sides 102, and opposing first short sides 103 and second short sides 104. The membrane bag 1 is wound along the extending direction of the first long side 101 to form the membrane element. The membrane bag 1 is formed by folding a thin base membrane sheet 100 along the first long side 101. The opposing inner surfaces of the membrane bag 1 are the raw water side, and the outer surfaces are the pure water side. During filtration, water flows into the raw water side, and the pure water formed by passing through the thin base membrane sheet 100 flows out from the first long side 101 side along the pure water flow channel 02. The remaining concentrated water on the raw water side is discharged from the first short side 103 or the second short side 104 along the raw water flow channel 01.

[0113] Furthermore, the thickness of the thin base film 100 is 0.01–0.03 mm, the softness is 2.2–3.5 g, and the stiffness is 2.5–4.0 cm. During winding, the film bag 1 is wound onto the central tube 2 by stretching and tensioning, so that the surface of the film bag 1 is a flat curved surface.

[0114] Because the flexibility range in this embodiment is relatively small, the surface will naturally exhibit many wrinkles. To ensure the flatness after film winding, tensioning can be applied to the film to create tension and make its surface flat. In practice, tension can be maintained by using tension rollers during winding, or the film can be wound at one end and held at the other end by two flat or curved surfaces.

[0115] Traditional membrane elements typically involve folding and winding along the short side.

[0116] 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 short-channel membrane element, comprising a membrane bag (1) having opposing first long sides (101) and second long sides (102), and opposing first short sides (103) and second short sides (104), the membrane bag (1) being wound along the extending direction of the first long side (101) to form the membrane element; characterized in that: The membrane bag (1) is formed by folding a thin base membrane (100) along the first long side (101). The inner side of the membrane bag (1) is the raw water side, and the outer side is the pure water side. During filtration, water flows into the raw water side, and the pure water formed by passing through the thin base membrane (100) flows out from the first long side (101) along the pure water channel (02). The remaining concentrated water on the raw water side is discharged from the concentrated water outlet along the raw water channel (01). The thin base film (100) has a thickness of 0.005 to 0.08 mm and a softness of 2.0 to 10 g, which enables it to eliminate the wrinkles formed at the first long side (101) during the roll-up process.

2. The short-channel membrane element according to claim 1, characterized in that: The stiffness of the thin base film (100) is 2.0 to 4.2 cm, and the surface of the rolled film bag (1) is a flat curved surface.

3. A short-channel membrane element according to claim 2, characterized in that: The thickness of the thin base film (100) is 0.01 to 0.04 mm.

4. A short-channel membrane element according to claim 1, characterized in that: On the pure water side of the membrane bag (1), at least the first short side (103), the second short side (104) and the second long side (102) are sealed, so that pure water passing through the thin base membrane (100) flows toward the first long side (101) and flows out from the end face where the first long side (101) of the membrane element is located.

5. A short-channel membrane element according to claim 4, characterized in that: A seal is formed at the second long side (102) of the raw water side of the membrane bag (1), and one side of the first short side (103) or the second short side (104) serves as the raw water inlet and the other side serves as the concentrate outlet.

6. A short-channel membrane element according to claim 4, characterized in that: On the raw water side of the membrane bag (1), the second long side (102) is partially sealed, so that a raw water inlet is formed near the middle of the second long side (102), and the first short side (103) and / or the second short side (104) serve as a concentrate outlet.

7. A short-channel membrane element according to claim 4, characterized in that: On the raw water side of the membrane bag (1), one of the first short side (103) or the second short side (104) is a sealed side, and the other short side forms a concentrated water outlet; the second long side (102) is partially sealed, so that a raw water inlet is reserved at one end of the second long side (102) near the sealed side.

8. A short-channel membrane element according to claim 1, characterized in that: The membrane bag (1) is provided with a raw water guide net (110) on the raw water side, and the raw water guide net (110) is basically the same size as the membrane bag (1) in the width direction; In the length direction, the raw water diversion net (110) is used to form a raw water flow channel.

9. A short-channel membrane element according to claim 8, characterized in that: The membrane element is provided with a pure water flow guide cloth (3), which is set on the pure water side of the membrane bag (1) to form a pure water flow channel.

10. A short-channel membrane element according to claim 8, characterized in that: The length of the membrane bag (1) along the first long side (101) is 1.0 to 4.6 m.

11. A short-channel membrane element, characterized in that: The device is provided with at least two membrane bags (1), the membrane bags (1) adopting the membrane bag (1) structure of the membrane element according to any one of claims 1-10, and a pure water flow guide cloth (3) is provided between adjacent membrane bags (1).

12. A short-channel membrane element according to claim 11, characterized in that: At least two of the membrane bags (1) are integral structures, formed by folding a thin base membrane (100) along the first long side (101) and then folding it a second time along the second short side (104); or: At least two of the membrane bags (1) are integral structures, which are formed by folding a thin base membrane (100) along the first long side (101) and then folding it again along the second long side (102) to form an M-shaped structure.

13. A filter element, characterized in that: The filter element comprises the membrane element as described in any one of claims 1-12.

14. A filter element according to claim 13, characterized in that: The filter element includes a central tube (2), which is parallel to the second short side (104) of the membrane bag (1). 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 (1) 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 (3).

15. A filter element according to claim 14, characterized in that: A raw water inlet is provided on the side of the second long side (102) near the central tube (2), and the first short side (103) is the raw water outlet, so that one end of the filter element is the raw water inlet and the other end is the pure water outlet.

16. A filter element according to claim 15, characterized in that: The pure water guide cloth (3) is connected to the central tube (2), and the second short side (104) of the membrane bag (1) is in a non-contact state with the central tube (2); The area between the second short side (104) and the central tube (2) is sealed at the pure water outlet to isolate the raw water.

17. A filter element according to claim 15, characterized in that: The central tube (2) has a hollow structure, forming a water flow cavity, which is used as a water flow channel for raw water, pure water or concentrated water.

18. A filter element according to claim 17, characterized in that: The central tube (2) protrudes axially from the first long side (101) and has a guide hole at the protruding position. A cavity is provided at the pure water outlet end, which is connected to the guide hole, so that the pure water connector and the raw water connector connected to the outside are located at the same end of the filter element.

19. A filter element according to claim 15, characterized in that: The outer shell of the filter element has a two-stage flow channel, and a cavity is provided at the pure water outlet. One end of the two-stage flow channel is connected to the cavity at the pure water outlet, and the other end is connected to the pure water connector, so that the pure water connector and the raw water connector connected to the outside are located at the same end of the filter element.

20. A filter element, characterized in that: It includes a central tube (2) and a membrane element as described in any one of claims 1-12, wherein the central tube (2) is parallel to the short side of the membrane bag (1), and at least one membrane element is wound on the central tube (2); during winding, the membrane bag (1) is wound on the central tube (2) by stretching and tensioning, so that the surface of the membrane bag (1) is a flat curved surface.

21. A filter element according to claim 20, characterized in that: The thickness of the thin base film (100) is 0.01-0.03 mm, the softness is 2.2-5.0 g, and the stiffness is 2.5-4.0 cm.

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