An open dual-channel reverse osmosis membrane assembly

Abstract

The present invention provides an open dual-channel reverse osmosis membrane assembly, comprising a membrane shell, a water production jacket arranged in the membrane shell, a central water production pipe arranged in the water production jacket, a membrane bag multilayer spiral structure formed by winding a plurality of membrane elements around the water production jacket in the form of membrane bags, and a plurality of spacer nets wound around the water production jacket to form a spacer net multilayer spiral structure, each of the spacer nets is an upper and lower two-layer structure formed by the intersection of a plurality of first rod-shaped elements and a plurality of second rod-shaped elements, and the upper and lower two-layer structure of each spacer net forms an open double-layer flow channel between two adjacent membrane bags, which can reduce the dislocation of membrane elements, reduce the deposition of pollutants, and reduce the dead angle area in the spacer net, and can be effectively used to treat highly polluted water sources.

Description

Technical Field

[0001] The invention belongs to the field of sewage concentration and purification reverse osmosis membrane components, and in particular relates to a double-channel membrane component with an open flow channel and an application thereof in the membrane component. Background Art

[0002] In recent years, membrane technology has developed rapidly and has been widely used in the fields of electricity, metallurgy, petroleum and petrochemicals, medicine, food, municipal engineering, sewage reuse and seawater desalination. The demand for membrane technology and its equipment in various projects has increased rapidly.

[0003] Membrane technology mostly uses ultrafiltration, reverse osmosis and nanofiltration to treat raw water. The device using this membrane technology includes a basically pressure-resistant membrane shell, in which a series of membrane elements are arranged. The membrane shell also includes an inlet for receiving the raw water to be separated into the membrane shell and for discharging pure water (or permeate) and retentate from the membrane shell respectively.

[0004] US Patent No. 6984321B2 discloses a device for filtering and separating a flowing medium (such as sewage) through a membrane, the device comprising a spacer net having a grid structure, the spacer net being composed of a plurality of first rod-shaped elements and a second rod-shaped element, and the diameter of the first rod-shaped element is larger than the second rod-shaped element, and the first rod-shaped element intersects the second rod-shaped element at a right angle. After appropriate arrangement, the first rod-shaped element of the spacer net is basically parallel to the central water production pipe, and at the same time, the raw water flowing through the multi-element spiral structure composed of the membrane bag encounters a flow resistance that is negligible when flowing through the second rod-shaped element. However, the disadvantage of this arrangement is that the contact between the spacer net and the surface of the membrane bag is relatively large, and the trapped pollutants are still likely to remain on the surface of the membrane bag. In addition, this arrangement is prone to telescope phenomenon. Whether in the membrane bag rolling process or in sewage treatment, the membranes in the reverse osmosis membrane element slip and the membrane cylinder wound into a column protrudes in the middle. The consequence is that the reverse osmosis membrane element structure is loose, the membrane surface is easily scratched, and the protruding membrane is easily brought out during the membrane bag rolling process. The result is poor product uniformity and stability, and a low yield rate.

[0005] Chinese patent application CN201611016142.2 sets an open spacer net in the water inlet flow channel between the membrane bag surfaces. According to the fluid characteristics and the pressure-bearing requirements of the membrane, the only part of the open spacer net in contact with the membrane bag surface is the convex point spacer net, which reduces the contact with the membrane surface while playing a supporting role. The membrane bag is formed by bonding two membranes with their front faces facing each other. A pure water guide net is set in the water production flow channel between the two membranes, and the filtered permeate flows out through the pure water guide net. The convex points are connected by a diamond-shaped spacer net, and a series of diamond-shaped spacious open flow channels are formed between the two rows of convex point spacers in contact with the membrane bag surface along the water inlet and outlet directions. When working, the water flows into the flow channel at a 45° angle to the diamond-shaped spacer net. The water flow with minimal resistance in the channel has a fast flow rate on the membrane surface. The suspended impurities brought in from the inlet water and the retained inorganic salts and organic matter are not easily blocked, but are discharged from the membrane element with the concentrated water flow, thus effectively avoiding the retained pollutants from adhering to the inlet channel and the membrane surface, causing membrane clogging and scaling due to concentration polarization. However, if Figure 1 As shown, the patent application adopts a traditional diamond-shaped spacer mesh structure, which is only applicable to low-pollution systems and is not suitable for filtering and separating highly polluted water sources, especially high-salt and high-organic water sources. Figure 1 There are two common forms of diamond mesh structures. Regardless of the diamond mesh structure, the common diamond mesh is a single flow channel. In the process of filtering highly polluted water sources, although water turbulence will be generated in the diamond mesh where the raw water flows, the incoming water flows in the same direction and needs to pass through all the first rod-shaped elements and the second rod-shaped elements. The resistance loss is large and the four corners of the diamond mesh are prone to form dead corners. This makes the diamond mesh appear with many dead corners, and pollutants are easily retained in the dead corners, resulting in poor filtration. In addition, the diamond mesh needs to be replaced frequently, and the product life is poor. Summary of the invention

[0006] In order to solve the deficiencies of the prior art, the present invention provides an open dual-channel reverse osmosis membrane assembly, comprising a membrane shell, a water production jacket arranged in the membrane shell, a central water production pipe arranged in the water production jacket, a membrane bag multilayer spiral structure formed by winding a plurality of membrane elements around the water production jacket in the form of a membrane bag, and a plurality of spacer nets wound around the water production jacket to form a spacer net multilayer spiral structure, the permeate outlet of the membrane bag multilayer spiral structure is connected to a plurality of axial channels of the water production jacket, and the permeate leaving the permeate outlet of the membrane bag multilayer spiral structure enters the permeate inlet of the central water production pipe through the axial channels. The water is discharged from the water production joint of the central water production pipe. The arrangement of the multi-layer spiral structure of the membrane bag and the multi-layer spiral structure of the spacer net should ensure that any two adjacent membrane bags are separated by a spacer net. Each spacer net is an upper and lower two-layer structure formed by the intersection of a plurality of first rod-shaped elements and a plurality of second rod-shaped elements. The plurality of first rod-shaped elements of each spacer net only contact the edge of one of the two adjacent membrane bags, and the plurality of second rod-shaped elements of each spacer net only contact the edge of the other of the two adjacent membrane bags, so that the upper and lower two-layer structure of each spacer net forms an open double-layer flow channel between the two adjacent membrane bags.

[0007] Furthermore, the membrane bag is composed of two membrane elements, and the two membrane elements are connected together at their peripheral edges.

[0008] Further, the plurality of first rod-shaped elements and the plurality of second rod-shaped elements intersect at an angle of 30 to 60 degrees.

[0009] Further, the plurality of first rod-shaped elements and the plurality of second rod-shaped elements intersect at an angle of 45 degrees.

[0010] Further, the diameters of each first rod-shaped element and each second rod-shaped element may be the same or different.

[0011] Furthermore, each first rod-shaped element and each second rod-shaped element may be in a circular shape, or in other geometric shapes.

[0012] Furthermore, the arrangement of the multi-layer spiral structure of the membrane bag and the multi-layer spiral structure of the spacer net enables water to flow into the double-layer flow channel in each spacer net at an angle of 45°.

[0013] Further, the length and width of each spacer mesh are substantially the same as those of each membrane pocket.

[0014] Further, each spacer net is made of elastic material.

[0015] Furthermore, an upper joint is provided at one end of the water inlet of the membrane shell, and a pressure-bearing upper flange is also provided at one end of the water inlet of the membrane shell. A water-passing upper flange is provided on the inner side of the pressure-bearing upper flange. The upper joint passes through the pressure-bearing upper flange and the water-passing upper flange in sequence and docks with the front end of the central guide tube of the membrane element.

[0016] Furthermore, a lower joint is provided at one end of the water outlet of the membrane shell, and a pressure-bearing lower flange is also provided at one end of the water outlet of the membrane shell, and an underwater flange is provided on the inner side of the pressure-bearing lower flange. The lower joint passes through the pressure-bearing lower flange and the underwater flange in sequence and docks with the end of the central guide pipe of the membrane element.

[0017] The beneficial effects of the present invention are as follows: (1) In the open dual-channel reverse osmosis membrane assembly of the present invention, each spacer net is a two-layer structure formed by the intersection of a plurality of first rod-shaped elements and a plurality of second rod-shaped elements, and the upper and lower layers of each spacer net form an open double-layer flow channel between two adjacent membrane bags, which can ensure that the water flowing through the spacer net generates turbulence and scouring force, and as little pollutant as possible is deposited on the surface of the membrane bag; (2) In the open dual-channel reverse osmosis membrane assembly of the present invention, each spacer net is a two-layer structure formed by the intersection of a plurality of first rod-shaped elements and a plurality of second rod-shaped elements, and the first rod-shaped elements and the second rod-shaped elements of each spacer net are of the same size, which can ensure that during rolling, the membrane elements will not be scratched due to misalignment or relaxation, thereby making the membrane elements The components are in place, thereby improving product uniformity, stability and yield; (3) The ordinary diamond-shaped spacer mesh is a single flow channel. Although it will also produce water turbulence, the incoming water has the same flow direction and needs to pass through all the first rod-shaped elements and the second rod-shaped elements. The resistance loss is large and the four corners of the diamond-shaped spacer mesh are prone to form dead corners. It is only suitable for low-pollution water source treatment. When treating highly polluted water sources, the diamond-shaped spacer mesh will have many dead corners. For this reason, the upper and lower layers of each spacer mesh of the present invention are staggered between two adjacent membrane bags to form an open two-layer flow channel that crosses up and down and has different water flow directions. The water flows in the two layers of the flow channel do not interfere with each other. From the beginning of water inflow, the water flows only in a single layer of the flow channel, which can effectively avoid the appearance of dead corners and can be used to treat highly polluted water sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 There are two common forms of diamond-shaped spacer mesh structures;

[0020] Figure 2 is a cross-sectional view of an open mesh pipe flow channel reverse osmosis membrane assembly of the present invention;

[0021] Figure 3 is a radial cross-sectional view of the membrane module;

[0022] Figure 4 It is an enlarged plan view of the spacer net. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0024] like Figure 1 The invention discloses an open dual-channel reverse osmosis membrane assembly, comprising a membrane shell 1, a water production jacket 2 arranged in the membrane shell 1, a central water production pipe 3 arranged in the water production jacket 2, and a plurality of membrane elements 4 arranged around the water production jacket 2, wherein an upper joint 5 is arranged at one end of the water inlet of the membrane shell 1, and a lower joint 6 is arranged at one end of the water outlet of the membrane shell 1.

[0025] A pressure-bearing upper flange 7 is provided at one end of the water inlet of the membrane shell 1, and a water-passing upper flange 8 is provided on the inner side of the pressure-bearing upper flange 7, and a sealing ring is provided between the pressure-bearing upper flange 7 and the water-passing upper flange 8 and the membrane shell 1. The upper joint 5 is connected to the raw water, passes through the pressure-bearing upper flange 7 and the water-passing upper flange 8 in sequence, and docks with the front end of the central flow guide tube of the membrane element 4. A sealing ring is provided between the upper joint 5 and the water-passing upper flange 8. The central water production pipe 3 and the water production sleeve 2 extend along the axial direction of the open dual-channel reverse osmosis membrane assembly. When it is needed, the central water production pipe 3 is inserted into the internal space 211 of the water production sleeve 2. When there is a problem with the central water production pipe 3, the central water production pipe 3 can be taken out of the water production sleeve 2 for repair or replacement.

[0026] The membrane housing 1 is provided with a pressure-bearing lower flange 9 at one end of the water outlet, and a water-passing submerged flange 10 is provided inside the pressure-bearing lower flange 9. A sealing ring is provided between the pressure-bearing lower flange 9 and the water-passing submerged flange 10 and the membrane housing 1. The lower joint 6 passes through the pressure-bearing lower flange 9 and the water-passing submerged flange 10 in sequence and docks with the end of the central flow guide pipe of the membrane element 4. A sealing ring is provided between the lower joint 6 and the water-passing submerged flange 10. Concentrated water generated during the filtration process of raw water is discharged through the lower joint 6.

[0027] One end of the central water production pipe 3 extends outward through the water-passing upper flange 8 and the pressure-bearing upper flange 7, and the central water production pipe 3 is fixed to the pressure-bearing upper flange 7 by the first support nut 11 and the first pressure-bearing nut 12. The first support nut 11 is adjacent to the first pressure-bearing nut 12 and is located outside the first pressure-bearing nut 12. A central axis gasket 13 is provided between the first pressure-bearing nut 12 and the pressure-bearing upper flange 7. The other end of the central water production pipe 3 extends outward through the water-passing lower flange 10 and the pressure-bearing lower flange 9, and the central water production pipe 3 is fixed to the pressure-bearing lower flange 9 by the second support nut 14 and the second pressure-bearing nut 15. The second support nut 14 is adjacent to the second pressure-bearing nut 15 and is located outside the second pressure-bearing nut 15. The portion of the central water production pipe 3 exposed outside the water-passing upper flange 8 and the water-passing lower flange 10 is a water production joint 16, and the permeate generated during the filtration process of the raw water is discharged through the water production joint 16.

[0028] During the rolling process, several membrane elements 4 are wound around the water production sleeve 2 in the form of membrane bags 41 to form a membrane bag multilayer spiral structure 42. In addition, several spacer nets 17 are wound around the water production sleeve 2 to form a spacer net multilayer spiral structure 43.

[0029] like Figure 3 As shown, the membrane bag multilayer spiral structure 42 includes a total of 18 membrane bags 41, and of course the number of membrane bags 41 can be adjusted according to actual needs. The permeate outlet 421 of the membrane bag multilayer spiral structure 42 is connected to the axial channel 210 of the water production sleeve 2. The permeate leaving the permeate outlet 421 of the membrane bag multilayer spiral structure 42 flows into the axial channel 210 of the water production sleeve 2, and then enters the permeate inlet 310 of the central water production pipe 3 through these axial channels 210, and then is discharged from the water production joint 16. A plurality of axial channels 210 are provided in the water production sleeve 2, and the number of axial channels 210 can be adjusted according to the length of the membrane bag 41 to ensure that the permeate leaving the membrane bag 41 is discharged uniformly. Each membrane bag 41 is composed of two membrane elements 4, which are connected at their peripheral edges in a known manner, such as by ultrasonic treatment or by a suitable adhesive.

[0030] like Figure 3 As shown in FIG. 1 , the spacer net multilayer spiral structure 43 includes 18 spacer nets 17. The number of the spacer nets 17 matches the number of the film bags 41. Of course, the number of the spacer nets 17 can be adjusted according to actual needs. The spacer nets 17 are represented by dotted lines, and the film bags 41 are represented by solid lines. During the rolling process, the arrangement of the film bag multilayer spiral structure 42 and the spacer net multilayer spiral structure 43 should ensure that any two adjacent film bags 41 are separated by one spacer net 17. The length and width of each spacer net 17 are substantially the same as those of the film bag 41.

[0031] like Figure 4As shown, the structure of each spacer net 17 has a lattice structure. The lattice structure of each spacer net 17 is formed by a plurality of first rod-shaped elements 171 and a plurality of second rod-shaped elements 172, and the second rod-shaped elements 172 are arranged on the first rod-shaped elements 171, and they intersect at 30 to 60 degrees (preferably 45 degrees), thereby forming an upper and lower two-layer structure. The diameter of the first rod-shaped element 171 is the same as the diameter of the second rod-shaped element 172. The first rod-shaped element 171 and the second rod-shaped element 172 are generally circular, and of course other shapes can be adopted as long as the water flow flowing through the membrane bag 41 in the membrane bag multi-layer spiral structure 42 generates turbulence. The spacer net 17 is made of an elastic material, such as an elastomeric resin.

[0032] like Figure 4 As shown, after the rolling process of the spacer net 17 and the film bag 41 is completed, it should be ensured that the spacer net 17 disposed between adjacent film bags 41 contacts the edge of the adjacent film bag 41, thereby preventing the adjacent film bags 41 from directly contacting each other. Given that each spacer net 17 is a two-layer structure, in any two adjacent film bags 41 separated by a spacer net 17, the multiple first rod-shaped elements 171 of the spacer net 17 only contact the edge of one of the film bags 41, and the multiple second rod-shaped elements 172 of the spacer net 17 only contact the edge of the remaining film bag 41, so the upper and lower two-layer structure of each spacer net 17 forms an open double-layer flow channel between adjacent film bags 41. The arrangement of the multi-layer spiral structure 42 of the membrane bag and the multi-layer spiral structure 43 of the spacing net should ensure that the water flows into the double-layer flow channel in the spacing net 17 at an angle of 45°, that is, part of the water flowing through the spacing net 17 flows along the first rod-shaped element 171, that is, the first flow channel 18, and part of the water flowing through the spacing net 17 flows along the second rod-shaped element 172, that is, the second flow channel 19. This arrangement can ensure that the water flowing through the spacing net 17 generates turbulence and scouring force, and as little pollutant as possible is deposited on the surface of the membrane bag 41. The upper and lower layers of each spacing net 17 are staggered to form two layers of flow channels that intersect each other and have different water flow directions. From the beginning of water inflow, the water flows only in a single flow channel, and the water flows in different flow channels do not interfere with each other. This overcomes the problem that the water inflow direction in the ordinary diamond grid of the single flow channel is the same, and it needs to pass through all the first rod-shaped elements and the second rod-shaped elements, resulting in large resistance loss and easy formation of dead corners. The permeate flowing through the first flow channel 18 and the second flow channel 19 passes through the permeate outlet 421 of the membrane bag multilayer spiral structure 42, flows into the axial channel 210 of the water production sleeve 2, and then enters the permeate inlet 310 of the central water production pipe 3 through these axial channels 210, and is then discharged from the water production joint 16.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An open dual-channel reverse osmosis membrane assembly, comprising a membrane shell, a water production jacket arranged in the membrane shell, a central water production pipe arranged in the water production jacket, a membrane bag multilayer spiral structure formed by winding a plurality of membrane elements around the water production jacket in the form of membrane bags, and a plurality of spacer nets wound around the water production jacket to form a spacer net multilayer spiral structure, characterized in that: The permeate outlet of the multi-layer spiral structure of the membrane bag is connected to the multiple axial channels of the water production sleeve. The permeate leaving the permeate outlet of the multi-layer spiral structure of the membrane bag enters the permeate inlet of the central water production pipe through the axial channel, and then is discharged from the water production joint of the central water production pipe. The arrangement of the multi-layer spiral structure of the membrane bag and the multi-layer spiral structure of the spacer net should ensure that any two adjacent membrane bags are separated by a spacer net. Each spacer net is an upper and lower two-layer structure formed by the intersection of multiple first rod-shaped elements and multiple second rod-shaped elements. The multiple first rod-shaped elements of each spacer net only contact the edge of one of the two adjacent membrane bags, and the multiple second rod-shaped elements of each spacer net only contact the edge of the other of the two adjacent membrane bags, so that the upper and lower two-layer structures of each spacer net form an open double-layer flow channel between the two adjacent membrane bags.

2. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: The membrane bag is composed of two membrane elements, and the two membrane elements are connected together at their peripheral edges.

3. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: The plurality of first rod-shaped elements and the plurality of second rod-shaped elements intersect at an angle of 30 to 60 degrees.

4. The open dual-channel reverse osmosis membrane assembly according to claim 3, characterized in that: The angle is 45 degrees.

5. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: The arrangement of the multi-layer spiral structure of the membrane bag and the multi-layer spiral structure of the spacer net enables the water to flow into the double-layer flow channel in each spacer net at an angle of 45°.

6. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: The length and width of each spacer mesh are substantially the same as those of each membrane bag.

7. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: Each spacer mesh is made of elastic material.

8. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: An upper joint is provided at one end of the water inlet of the membrane shell, and a pressure-bearing upper flange is also provided at one end of the water inlet of the membrane shell. A water-passing upper flange is provided on the inner side of the pressure-bearing upper flange. The upper joint passes through the pressure-bearing upper flange and the water-passing upper flange in sequence and docks with the front end of the central guide pipe of the membrane element.

9. The open dual-channel reverse osmosis membrane assembly according to claim 1, characterized in that: A lower joint is provided at one end of the water outlet of the membrane shell, and a pressure-bearing lower flange is also provided at one end of the water inlet of the membrane shell. An underwater flange is provided on the inner side of the pressure-bearing lower flange. The lower joint passes through the pressure-bearing lower flange and the underwater flange in sequence and docks with the end of the central guide pipe of the membrane element.

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