CDRO-based roll type filtering membrane element and sewage treatment system

Abstract

The utility model belongs to the technical field of water treatment, and discloses a CDRO-based spiral-wound filter membrane element and a sewage treatment system, wherein the CDRO-based spiral-wound filter membrane element is high in total membrane area, small in pressure drop and easy to seal. The spiral-wound filtering membrane element comprises a membrane shell, a first end cover assembly, a second end cover assembly and a spiral-wound membrane cylinder, the first end cover assembly is provided with a liquid inlet channel, a concentrated liquid discharge channel and a clear liquid discharge channel and comprises a first sealing cover, and a first mounting position is arranged in the first sealing cover; the second end cover assembly is provided with a water distribution channel and comprises a second sealing cover, and a second mounting position is arranged in the second sealing cover; a first flow channel is formed between the outer wall of the spiral-wound membrane cylinder and the inner wall of the membrane shell; the spiral-wound membrane cylinder comprises a water collecting pipe and a membrane bag; and the membrane bag is wound along the circumferential direction of the water collecting pipe to form a second flow channel distributed along the axial direction of the membrane shell. Concentrated liquid formed after the stock solution penetrates through the second flow channel is discharged from the concentrated liquid discharge channel, and clear liquid formed after the stock solution enters the membrane bag sequentially flows through the water collecting pipe and the clear liquid discharge channel and then is discharged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of water treatment, and particularly relates to a CDRO-based roll type filter membrane element and a sewage treatment system. BACKGROUND

[0002] The CDRO membrane element refers to a water treatment element composed of a membrane stack formed by alternately stacking CD-shaped reverse osmosis (RO) membrane sheets and flow guide discs, an outer shell, a water collecting pipe, flanges at both ends, and a sealing cover, etc. The working principle is as follows: the raw liquid first passes through the gap between the membrane stack and the outer shell, then enters the bottom flow guide disc through the flow guide channel on the lower end sealing cover; under the action of pressure, the raw liquid flows circumferentially on the surface of the bottom RO membrane sheet, in the process, water molecules pass through the RO membrane sheet into the water collecting pipe and are continuously discharged as clean liquid, while inorganic salts, organic matter, colloids, and suspended solids, etc. are intercepted and flow into the flow guide disc and the RO membrane sheet of the upper layer through the flow guide slit, and the process is repeated until the concentrated liquid is discharged from the liquid discharge channel on the upper end sealing cover after passing through the flow guide disc and the RO membrane sheet of the uppermost layer.

[0003] However, due to the space occupied by the flow guide disc, the total membrane area is generally only 15-17 square meters, and the water production is small; and due to the flow process of the raw liquid from bottom to top, which includes a cyclone process of nearly 180° (when the flow guide slit is 2) or 360° (when the flow guide slit is 1) on each RO membrane sheet, the flow path is too long, the pressure drop of the membrane assembly is large, the energy consumption is high, and the RO membrane sheet is not easy to clean. In addition, O-rings are required for sealing between the center of each flow guide disc and the water collecting pipe, and the sealing point is multiple, and the sealing safety is poor. UTILITY MODEL CONTENTS

[0004] The technical problem to be solved by the utility model is to provide a CDRO-based roll type filter membrane element and a sewage treatment system with high total membrane area, small pressure drop, and easy sealing, and the technical scheme is as follows:

[0005] The CDRO-based roll type filter membrane element comprises a membrane shell, a first end cover assembly and a second end cover assembly respectively arranged at both ends of the membrane shell, and a roll type membrane cylinder compressed between the first end cover assembly and the second end cover assembly; wherein:

[0006] The first end cover assembly is provided with a liquid inlet channel, a concentrated liquid discharge channel, and a clean liquid discharge channel; the first end cover assembly comprises a first sealing cover and a first flange; the first sealing cover is internally provided with a first mounting position adapted to one end of the roll type membrane cylinder;

[0007] The second end cover assembly is provided with a water distribution channel; the second end cover assembly comprises a second sealing cover and a second flange; the second sealing cover is internally provided with a second mounting position adapted to the other end of the roll type membrane cylinder;

[0008] The first flow channel is formed between the outer wall of the spiral membrane cylinder and the inner wall of the membrane shell;

[0009] The spiral membrane cylinder comprises a water collecting pipe and a membrane bag, the open end of the membrane bag is connected with the water collecting pipe, the water collecting pipe is provided with a water guide hole in communication with the open end of the membrane bag, and the membrane bag is wound along the circumference of the water collecting pipe to form a second flow channel distributed along the axial direction of the membrane shell;

[0010] The raw solution sequentially flows through the liquid inlet channel, the first flow channel, the water distribution channel and the second flow channel, the concentrated solution formed after the raw solution passes through the second flow channel along the axial direction of the membrane shell is discharged from the concentrated solution discharge channel, and the clear solution formed after the raw solution enters the membrane bag (110) along the radial direction of the membrane shell is sequentially discharged from the water collecting pipe and the clear solution discharge channel.

[0011] As a further improvement of the CDRO-based spiral filtration membrane element described above:

[0012] The first sealing cover and the membrane shell are sealingly connected through the first sealing ring, and the second sealing cover and the membrane shell are sealingly connected through the first sealing ring;

[0013] The first sealing cover and the first flange, and the second sealing cover and the second flange are connected through the internal hexagonal screw;

[0014] The first flange and the second flange are fixedly connected through the pull rod and the nut.

[0015] As a further improvement of the CDRO-based spiral filtration membrane element described above:

[0016] The first gap is formed between the outer wall of the first sealing cover and the inner wall of the membrane shell, and the first gap is in communication with the first flow channel; and the first sealing cover is internally provided with a first cavity;

[0017] The liquid inlet channel comprises a first axial through hole provided on the first flange, an axial blind hole provided on the first sealing cover, and a first radial channel connecting the axial blind hole and the first gap;

[0018] The concentrated solution discharge channel comprises a second axial through hole provided on the first flange and a third axial through hole provided on the first sealing end cover, and the third axial through hole is in communication with the first cavity;

[0019] The clear solution discharge channel comprises a fourth axial through hole provided on the first flange, a fifth axial through hole provided on the first sealing end cover, and an adapter connecting the fifth axial through hole and the water collecting pipe.

[0020] As a further improvement of the CDRO-based spiral filtration membrane element described above:

[0021] The longitudinal section of the first cavity is in the shape of U;

[0022] The first radial channels are four;

[0023] The adapter has a first step matched with the fifth axial through hole and the water collecting pipe;

[0024] A plurality of first protrusions are arranged on the outer wall of the first sealing cover in a circumferential direction, and a first connecting port connecting the first gap and the first flow channel is formed between adjacent first protrusions.

[0025] As a further improvement of the CDRO-based roll-type filtration membrane element described above: the first end cover assembly further comprises a liquid inlet pipe connected with the first axial through hole and the axial blind hole, a concentrated liquid discharge pipe connected with the second axial through hole and the third axial through hole, and a clear liquid discharge pipe connected with the fourth axial through hole and the fifth axial through hole.

[0026] As a further improvement of the CDRO-based roll-type filtration membrane element described above:

[0027] The liquid inlet pipe, the concentrated liquid discharge pipe, and the clear liquid discharge pipe are connected with the first flange through a locking ring;

[0028] Second sealing rings are arranged between the liquid inlet pipe and the axial blind hole, between the concentrated liquid discharge pipe and the third axial through hole, between the clear liquid discharge pipe and the fifth axial through hole, between the adapter and the fifth axial through hole, and between the adapter and the water collecting pipe.

[0029] As a further improvement of the CDRO-based roll-type filtration membrane element described above:

[0030] A second gap is formed between the outer wall of the second sealing cover and the inner wall of the membrane shell, and the second gap is in communication with the first flow channel; a second cavity is arranged inside the second sealing cover;

[0031] The water distribution channel comprises second radial channels connecting the second gap and the second cavity;

[0032] A blocking member is arranged between the end of the water collecting pipe and the second cavity.

[0033] As a further improvement of the CDRO-based roll-type filtration membrane element described above:

[0034] The second radial channels are six and uniformly distributed in a circumferential direction;

[0035] A plurality of second protrusions are arranged on the outer wall of the second sealing cover in a circumferential direction, and a second connecting port connecting the second gap and the first flow channel is formed between adjacent second protrusions.

[0036] The blocking member comprises a support rod connected at one end with the bottom of the second cavity and at the other end with the end of the water collecting pipe.

[0037] As a further improvement of the CDRO-based roll-type filtration membrane element described above:

[0038] The second cavity bottom is provided with a slot matched with the support rod;

[0039] The support rod and the water collecting pipe are provided with a second sealing ring;

[0040] The support rod is provided with a second step matched with the water collecting pipe.

[0041] The sewage treatment system comprises the CDRO-based roll-type filter membrane element.

[0042] The CDRO-based roll-type filter membrane element and the sewage treatment system have the following advantages:

[0043] (1) Compared with the total membrane area of 15-17 square meters of the membrane stack formed by the alternately stacked RO membrane and flow guide disc, the total membrane area of the roll-type membrane cylinder formed by the membrane bag can reach 40-50 square meters, which is more than 3 times of the total membrane area of the conventional RO membrane stack. The increase of the total membrane area increases the water treatment capacity per unit time, thereby significantly improving the water production capacity. It has been verified that under the condition of the same water quality and element land size, the water production capacity of the roll-type filter membrane element is 2-3 times of that of the conventional CDRO membrane element. Moreover, when treating the same amount of water, the membrane flux (unit membrane area water production capacity) can be reduced due to the significant increase of the membrane area, thereby prolonging the service life of the roll-type membrane cylinder.

[0044] (2) Compared with the high pressure drop process caused by the multiple nearly 360° rotational flow of the raw liquid from bottom to top in the RO membrane stack, the winding of the membrane bag in the roll-type membrane cylinder forms an axial second flow channel, so that the flow path of the raw liquid from bottom to top is significantly shortened, the pressure drop is significantly reduced, and the energy consumption is effectively reduced. Since the second flow channels are overlapped, although the single flow path from bottom to top is significantly shortened, the number of flow paths of the raw liquid is increased, and the membrane area is increased, thereby increasing the water treatment capacity. At the same time, a larger flow can be used to flush the membrane surface, thereby improving the anti-fouling capacity of the roll-type membrane cylinder.

[0045] (3) Compared with the sealing mode in which O-rings are used between the center of each flow guide disc and the water collecting pipe in the RO membrane stack, the membrane bag in the roll-type membrane cylinder is bonded by glue, and O-rings are not needed, so that 90% of the sealing points can be reduced, the sealing is safer, and the service life is longer.

[0046] (4) the traditional roll type filter membrane element usually connects multiple roll type membrane cylinders and is tightly attached with the membrane shell, then water is directly fed from the head membrane cylinder and drained from the tail membrane cylinder, once the water quality problem occurs, immediate shutdown inspection is needed, but it is unable to quickly determine which membrane cylinder is damaged, the maintenance procedure is very cumbersome and the cost is very high, while the roll type filter membrane element based on the CDRO of the utility model and the sewage treatment system are successfully packaged and parallelly arranged by adjusting the structure, and are applied to water treatment, each roll type filter membrane element can be independently shut down and maintained, and are more convenient to use.

[0047] In conclusion, the roll type filter membrane element based on the CDRO and the sewage treatment system have the advantages of simple structure, convenient processing and manufacturing, low investment and operation cost, convenient use, significantly improved water treatment efficiency, effectively solve the technical problems of the RO membrane stack in the existing CDRO membrane element, high total membrane area, small pressure drop and easy sealing, and have strong practicability in the field of water treatment.

[0048] The utility model will be further described in combination with the drawings and specific embodiments. The additional aspects and advantages of the utility model will be partially given in the following description, partially become obvious from the following description, or be known by the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0049] The drawings that constitute a part of the utility model are used to assist the understanding of the utility model, the content provided in the drawings and its related description in the utility model can be used to explain the utility model, but do not constitute improper limitation on the utility model.

[0050] Figure 1 It is the structure schematic view of the roll type filter membrane element based on the CDRO of the utility model.

[0051] Figure 2 It is the structure schematic view of the unrolled state of the membrane cylinder of the roll type membrane element of the utility model.

[0052] Figure 3 It is the structure schematic view of a single membrane bag in the roll type membrane element of the utility model.

[0053] Figure 4 It is the structure schematic view of the first flange of the utility model.

[0054] Figure 5 It is the structure schematic view of the first sealing cover of the utility model.

[0055] Figure 6 It is the structure schematic view of the second flange of the utility model.

[0056] Figure 7It is a structural schematic diagram of the second sealing cover of the utility model.

[0057] The relevant marks in the above drawings are:

[0058] 100-membrane cylinder, 110-membrane bag, 111-diaphragm, 112-clear liquid separator, 113-clear liquid cavity, 114-adhesive layer, 115-open end, 120-concentrated water separator, 130-clear liquid flow channel, 140-fixing ring, 150-collecting pipe, 151-water guide hole, 160-second flow channel, 200-membrane shell, 210-first flow channel, 220-first gap, 230-second gap, 300-first sealing cover, 310-first cavity, 320-first protrusion, 330-axial blind hole, 340-first radial channel, 350-third axial through hole, 360-fifth axial through hole, 370-adapter, 38 0-first mounting position, 400-first flange, 410-first axial through hole, 420-second axial through hole, 430-fourth axial through hole, 500-second sealing cover, 510-second cavity, 520-second protrusion, 530-second radial channel, 540-support rod, 550-second mounting position, 560-slot, 600-second flange, 710-nut, 720-flange hole, 730-screw through hole, 740-screw blind hole, 750-lifting threaded hole, 760-first sealing ring, 770-second sealing ring, 780-locking ring, 810-liquid inlet pipe, 820-concentrated liquid drain pipe, 830-clear liquid drain pipe. DETAILED DESCRIPTION

[0059] The following is a clear and complete description of the present invention in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be noted that:

[0060] The technical solutions and technical features provided in each part of the present invention, including the following description, can be combined with each other if there is no conflict.

[0061] In addition, the embodiments of the present invention described below are generally only part of the embodiments of the present invention, rather than all of the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative effort should fall within the scope of protection of the present invention.

[0062] Regarding the terms and units in the present invention: The terms "include", "have" and any variations thereof in the description and claims of the present invention and related parts are intended to cover non-exclusive inclusions.

[0063] Figure 1 It is the structural schematic diagram of the CDRO-based roll type filter membrane element of the utility model. Figure 2 It is the structural schematic diagram of the unrolled state of the roll type membrane cylinder of the utility model. Figure 3 It is the structural schematic diagram of the single membrane bag of the utility model. Figure 4 It is the structural schematic diagram of the first flange of the utility model. Figure 5 It is the structural schematic diagram of the first sealing cover of the utility model. Figure 6 It is the structural schematic diagram of the second flange of the utility model. Figure 7 It is the structural schematic diagram of the second sealing cover of the utility model.

[0064] As shown in Figures 1-7 The embodiment of the CDRO-based roll type filter membrane element of the utility model is provided with a membrane shell 200, a first end cover assembly and a second end cover assembly arranged at both ends of the membrane shell 200 respectively, and a roll type membrane cylinder compressed between the first end cover assembly and the second end cover assembly.

[0065] The first end cover assembly comprises a first sealing cover 300 and a first flange 400, and the second end cover assembly comprises a second sealing cover 500 and a second flange 600. The first flange 400 and the second flange 600 are provided with matched flange holes 720, and the first flange 400 and the second flange 600 are fixedly connected by pulling through the flange holes 720 and through the nuts 710. The first sealing cover 300 is internally provided with a first mounting position 380 matched with one end of the roll type membrane cylinder. The second sealing cover 500 is internally provided with a second mounting position 550 matched with the other end of the roll type membrane cylinder.

[0066] The outer wall of the roll type membrane cylinder 100 and the inner wall of the membrane shell 200 form a first flow channel 210; the roll type membrane cylinder 100 is arranged by a plurality of groups of membrane bags 110 and concentrated water separation nets 120, and is wound along the outer wall of the water collecting pipe 150, and forms a second flow channel 160 distributed along the axial direction of the membrane shell 200 after being wound along the circumferential direction of the water collecting pipe 150, and the two ends of the roll type membrane cylinder 100 are fixed by the fixing rings 140. The outer part of the fixing ring 140 is provided with a first sealing ring 760, and the fixing rings 140 at both ends are sealingly connected with the first mounting position 380 and the second mounting position 550 respectively.

[0067] The membrane bag 110 is bag-shaped and usually rectangular, and is bonded by two layers of film sheets 111 arranged in overlap, and a clear liquid cavity 113 is formed between the two layers of film sheets 111, and a clear liquid separation net 112 is arranged in the clear liquid cavity 113. The film sheet 111 is a reverse osmosis film sheet, and the edges of the film sheet 111 arranged in overlap are bonded by a bonding layer 114 except the opening end 115. The opening end 115 of the membrane bag 110 is connected with the water collecting pipe 150, and the water collecting pipe 150 is provided with a water guide hole 151 in communication with the opening end 115 of the membrane bag 110.

[0068] The inner side of the spiral membrane cartridge 100 is wrapped by the multilayer clear liquid screen 112 on the surface of the water collecting pipe 150, forming a cylindrical clear liquid flow channel 130, and the multilayer clear liquid screen 112 at both axial ends of the clear liquid flow channel 130 is sealed and fixed by glue. The clear liquid flow channel 130 can provide support for the spiral membrane cartridge 100 on the one hand, and improve the flowability of the clear liquid on the surface of the water collecting pipe 150 on the other hand, thereby promoting the rapid flow of the clear liquid into the water collecting pipe 150.

[0069] The raw liquid flows in the second flow channel 160 between adjacent membrane bags 110 under the flow guiding action of the concentrated water screen 120. Due to the physical interception action of the membrane sheet 111, the clear liquid passing through the membrane sheet 111 enters the clear liquid cavity 113 inside the membrane bag 110, and then flows into the inside of the water collecting pipe 150 under the flow guiding action of the clear liquid screen 112 and the water guiding hole 151 opened on the pipe wall of the water collecting pipe 150 and is discharged.

[0070] The first sealing cover 300 and the membrane shell 200 are sealingly connected by the first sealing ring 760, and the second sealing cover 500 and the membrane shell 200 are sealingly connected by the first sealing ring 760. The first sealing cover 300 and the first flange 400 and the second sealing cover 500 and the second flange 600 are connected by the inner hexagonal screw, and correspondingly, the screw through hole 730 is arranged on the first flange 400 and the second flange 600, and the screw blind hole 740 is arranged on the first sealing cover 300 and the second sealing cover 500. In order to facilitate hoisting, the hoisting threaded hole 750 is further arranged on the first flange 400 and the second flange 600.

[0071] The first sealing cover 300 and the membrane shell 200 form a first gap 220 between the outer wall of the first sealing cover 300 and the inner wall of the membrane shell 200, and the first gap 220 is in communication with the first flow channel 210. The first cavity 310 is arranged in the first sealing cover 300, and the longitudinal section of the first cavity 310 is in U shape. A plurality of first protrusions 320 are arranged on the outer wall of the first sealing cover 300 and spaced apart in the circumferential direction, and the first connecting port connecting the first gap 220 and the first flow channel 210 is formed between adjacent first protrusions 320.

[0072] The first end cover assembly is provided with a liquid inlet channel, a concentrated liquid discharge channel and a clear liquid discharge channel. The liquid inlet channel comprises a first axial through hole 410 provided on the first flange 400, an axial blind hole 330 provided on the first sealing cover 300 and a first radial channel 340 connecting the axial blind hole 330 and the first gap 220, and the first radial channel 340 is four. The concentrated liquid discharge channel comprises a second axial through hole 420 provided on the first flange 400 and a third axial through hole 350 provided on the first sealing end cover, and the third axial through hole 350 is in communication with the first cavity 310. The clear liquid discharge channel comprises a fourth axial through hole 430 provided on the first flange 400, a fifth axial through hole 360 provided on the first sealing end cover and an adapter 370 connecting the fifth axial through hole 360 and the water collecting pipe 150, and the adapter 370 has a first step adapted to the fifth axial through hole 360 and the water collecting pipe 150.

[0073] The first end cover assembly further comprises a liquid inlet pipe 810 connected with the first axial through hole 410 and the axial blind hole 330, a concentrated liquid discharge pipe 820 connected with the second axial through hole 420 and the third axial through hole 350, and a clear liquid discharge pipe 830 connected with the fourth axial through hole 430 and the fifth axial through hole 360. The liquid inlet pipe 810, the concentrated liquid discharge pipe 820 and the clear liquid discharge pipe 830 are connected with the first flange 400 through a locking ring 780. Second sealing rings 770 are arranged between the liquid inlet pipe 810 and the axial blind hole 330, between the concentrated liquid discharge pipe 820 and the third axial through hole 350, between the clear liquid discharge pipe 830 and the fifth axial through hole 360, between the adapter 370 and the fifth axial through hole 360, and between the adapter 370 and the water collecting pipe 150.

[0074] The second gap 230 is formed between the outer wall of the second sealing cover 500 and the inner wall of the membrane shell 200, and the second gap 230 is in communication with the first flow channel 210. The second cavity 510 is arranged in the second sealing cover 500. A plurality of second protrusions 520 are arranged on the outer wall of the second sealing cover 500 in a circumferential direction, and a second connecting port connecting the second gap 230 and the first flow channel 210 is formed between adjacent second protrusions 520.

[0075] The second end cover assembly is provided with a water distribution channel, and the water distribution channel comprises six second radial channels 530 connecting the second gap 230 and the second cavity 510 and uniformly distributed in the circumferential direction.

[0076] The end of the water collecting pipe 150 and the second cavity 510 are provided with a blocking piece, which comprises a support rod 540 connected with one end of the bottom of the second cavity 510 and the other end of the end of the water collecting pipe 150. A slot 560 adapted to the support rod 540 is arranged at the bottom of the second cavity 510, and the support rod 540 is threadedly connected or tightly matched with the slot 560. The support rod 540 and the water collecting pipe 150 are provided with a second sealing ring 770. The support rod 540 is provided with a second step adapted to the water collecting pipe 150.

[0077] The first sealing ring 760 and the second sealing ring 770 are Y-shaped sealing rings or O-shaped sealing rings.

[0078] The raw solution flows through the liquid inlet channel, the first flow channel 210, the water distribution channel and the second flow channel 160 in sequence, and the concentrated solution formed by the raw solution passing through the second flow channel 160 along the membrane shell axis is discharged after flowing through the first cavity 310, the third axial through hole 350 and the concentrated solution discharge pipe 820 in sequence. The clear solution formed by the raw solution entering the clear solution cavity 113 inside the membrane bag 110 along the membrane shell radius is discharged after flowing through the water collecting pipe 150, the adapter 370, the fifth axial through hole 360 and the clear solution discharge pipe 830 in sequence.

[0079] The embodiment of the sewage treatment system of the utility model is provided with a plurality of CDRO-based roll type filter membrane elements, and the roll type filter membrane elements are used in parallel.

[0080] The related content of the utility model is described above. The ordinary skilled in the art can realize the utility model based on the description. Based on the above content of the utility model, all other embodiments obtained by the ordinary skilled in the art without creative labor should belong to the protection scope of the utility model.

Claims

1. A CDRO-based spiral wound filtration membrane element, characterized by: The CDRO-based spiral filtration membrane element comprises a membrane shell (200), a first end cover assembly and a second end cover assembly arranged at two ends of the membrane shell (200) respectively, and a spiral membrane cartridge (100) compressed between the first end cover assembly and the second end cover assembly. The first end cover assembly is provided with a liquid inlet channel, a concentrated liquid discharge channel and a clear liquid discharge channel; the first end cover assembly comprises a first sealing cover (300) and a first flange (400); the first sealing cover (300) is internally provided with a first mounting position (380) adapted to one end of the spiral membrane cartridge (100); The second end cover assembly is provided with a water distribution channel; the second end cover assembly comprises a second sealing cover (500) and a second flange (600); the second sealing cover (500) is internally provided with a second mounting position (550) adapted to the other end of the spiral membrane cartridge (100); The outer wall of the spiral membrane cartridge (100) and the inner wall of the membrane shell (200) form a first flow channel (210); The spiral membrane cartridge (100) comprises a water collecting pipe (150) and a membrane bag (110); the opening end of the membrane bag (110) is connected with the water collecting pipe (150); the water collecting pipe (150) is provided with a water guide hole (151) in communication with the opening end of the membrane bag (110); the membrane bag (110) is wound along the circumference of the water collecting pipe (150) to form a second flow channel (160) distributed along the axial direction of the membrane shell (200); The raw liquid sequentially flows through the liquid inlet channel, the first flow channel (210), the water distribution channel and the second flow channel (160); the concentrated liquid formed after the raw liquid passes through the second flow channel (160) along the axial direction of the membrane shell is discharged from the concentrated liquid discharge channel; and the clear liquid formed after the raw liquid enters the membrane bag (110) along the radial direction of the membrane shell is sequentially discharged through the water collecting pipe (150) and the clear liquid discharge channel.

2. The CDRO-based spiral filtration membrane element according to claim 1, wherein: The first sealing cover (300) and the membrane shell (200) and the second sealing cover (500) and the membrane shell (200) are sealingly connected through a first sealing ring (760); The first sealing cover (300) and the first flange (400) and the second sealing cover (500) and the second flange (600) are connected through an internal hexagonal screw; The first flange (400) and the second flange (600) are fixedly connected through a pull rod and a nut (710).

3. The CDRO-based spiral filtration membrane element according to claim 1, wherein: The outer wall of the first sealing cover (300) and the inner wall of the membrane shell (200) form a first gap (220), and the first gap (220) is in communication with the first flow channel (210); the first sealing cover (300) is internally provided with a first cavity (310); The liquid inlet channel comprises a first axial through hole (410) arranged on the first flange (400), an axial blind hole (330) arranged on the first sealing cover (300) and a first radial channel (340) connecting the axial blind hole (330) and the first gap (220); The concentrated liquid discharge channel comprises a second axial through hole (420) arranged on the first flange (400) and a third axial through hole (350) arranged on the first sealing end cover, and the third axial through hole (350) is in communication with the first cavity (310); The clear liquid discharge channel comprises a fourth axial through hole (430) arranged on the first flange (400), a fifth axial through hole (360) arranged on the first sealing end cover, and an adapter (370) connecting the fifth axial through hole (360) and the water collecting pipe (150).

4. The CDRO-based spiral wound filtration membrane element according to claim 3, wherein: The longitudinal section of the first cavity (310) is U-shaped; The first radial channel (340) is four; The adapter (370) has a first step matched with the fifth axial through hole (360) and the water collecting pipe (150); A plurality of first protrusions (320) are arranged on the outer wall of the first sealing cover (300) in a circumferential direction, and a first connecting port connecting the first gap (220) and the first flow channel (210) is formed between adjacent first protrusions (320).

5. The CDRO-based spiral wound membrane element of claim 4, wherein: The first end cover assembly further comprises a liquid inlet pipe (810) connected with the first axial through hole (410) and the axial blind hole (330), a concentrated liquid discharge pipe (820) connected with the second axial through hole (420) and the third axial through hole (350), and a clear liquid discharge pipe (830) connected with the fourth axial through hole (430) and the fifth axial through hole (360).

6. The CDRO-based spiral wound filtration membrane element according to claim 5, wherein: The liquid inlet pipe (810), the concentrated liquid discharge pipe (820) and the clear liquid discharge pipe (830) are connected with the first flange (400) through a locking ring (780); Second sealing rings (770) are arranged between the liquid inlet pipe (810) and the axial blind hole (330), between the concentrated liquid discharge pipe (820) and the third axial through hole (350), between the clear liquid discharge pipe (830) and the fifth axial through hole (360), between the adapter (370) and the fifth axial through hole (360), and between the adapter (370) and the water collecting pipe (150).

7. The CDRO-based spiral wound filtration membrane element according to claim 1, wherein: A second gap (230) is formed between the outer wall of the second sealing cover (500) and the inner wall of the membrane shell (200), and the second gap (230) is in communication with the first flow channel (210); and a second cavity (510) is arranged inside the second sealing cover (500); The water distribution channel comprises a second radial channel (530) connecting the second gap (230) and the second cavity (510); A plugging member is arranged between the end of the water collecting pipe (150) and the second cavity (510).

8. The CDRO-based spiral wound filtration membrane element according to claim 7, wherein: The second radial channel (530) is six and is uniformly distributed in a circumferential direction. A plurality of second protrusions (520) are arranged on the outer wall of the second sealing cover (500) in a circumferential direction, and a second connecting port connecting the second gap (230) and the first flow channel (210) is formed between adjacent second protrusions (520); The sealing member comprises a support rod (540) connected at one end to the bottom of the second cavity (510) and at the other end to the end of the water collecting pipe (150).

9. The CDRO-based spiral filtration membrane element according to claim 8, characterized in that: A slot (560) is arranged at the bottom of the second cavity (510) and is adapted to the support rod (540); A second sealing ring (770) is arranged between the support rod (540) and the water collecting pipe (150); A second step is arranged on the support rod (540) and is adapted to the water collecting pipe (150).

10. A sewage treatment system characterised by: The CDRO-based spiral filtration membrane element according to any one of claims 1-9.

Images