CN210595383U - Spiral wound reverse osmosis membrane element and reverse osmosis module comprising same - Google Patents

Abstract

The application discloses a spiral wound reverse osmosis membrane element and a reverse osmosis module comprising the same, comprising a first reverse osmosis membrane group spirally wound around a first central water collecting pipe; a second reverse osmosis membrane module spirally wound around the second central collector pipe; and a connector connecting the first central header in fluid communication with the second central header; wherein an outer region of a side surface of a downstream end of the first reverse osmosis membrane module, which is remote from the first central tube, and an outer region of a side surface of an upstream end of the second reverse osmosis membrane module, which is remote from the second central tube, are sealed; and an outer region of a junction between the two reverse osmosis membrane modules is sealed so that concentrated water from a downstream end of the first reverse osmosis membrane module can flow into an upstream end of the second reverse osmosis membrane module.

Description

Spiral wound reverse osmosis membrane element and reverse osmosis module comprising same

Technical Field

The present invention relates to spiral wound reverse osmosis membrane (membrane) elements. In particular, the present invention provides a spiral wound reverse osmosis membrane element having an extended life and a more convenient method of manufacturing the same.

Background

Pressure driven spiral reverse osmosis membrane elements are widely used in household water purifiers to provide purified water to consumers. The use of a spiral wound reverse osmosis membrane is advantageous because it provides the consumer with very high quality water.

Conventionally, a spiral wound reverse osmosis membrane element is formed by winding a plurality of purification membrane modules around a water pipe treated with a central perforation. The purification membrane module is formed by laminating a net-shaped treated water guide member, a double-folded reverse osmosis membrane, and a net-shaped water supply guide member inside the double-folded reverse osmosis membrane. An inlet water flow passage is formed along an inner surface of the double-folded reverse osmosis membrane, and a treated water flow passage is formed between outer surfaces of adjacent double-folded reverse osmosis membranes.

When such a membrane element is operated, feed water enters the feed water flow channel from one end (side surface or outer surface) of the spiral wound reverse osmosis membrane element. Treated water is obtained by passing influent water through the membrane. The treated water flows along the treated water guide member and enters the central treated water pipe through the water collecting hole. The remaining unfiltered water flows along the feed water guide element and exits the other end of the spiral reverse osmosis membrane element as concentrate. In such a conventional spiral wound reverse osmosis membrane element, the water flow path is short, and thus the rate of water inflow is relatively slow. Therefore, the membrane is easily contaminated by impurities, resulting in a shortened life span of the reverse osmosis membrane element.

Many efforts have been made to improve the life of spiral wound reverse osmosis membrane elements. However, few of them can be produced in a manner suitable for factory manufacturing. Accordingly, the present inventors have recognized the need to develop a spiral wound reverse osmosis membrane element having an extended life and ease of manufacture, and a method for manufacturing such a membrane element suitable for industrialization.

Disclosure of Invention

In a first aspect, the present invention relates to a spiral wound reverse osmosis membrane element (1) comprising (a) a first reverse osmosis membrane module (2) spirally wound around a first central collection pipe (3); (b) a second reverse osmosis membrane module (4) spirally wound around a second central water collection pipe (5); and (c) a connector (6) connecting the first central header (3) in fluid communication with the second central header (5); wherein an outer region (221) of the side surface (22) of the downstream end (21) of the first reverse osmosis membrane group (2) remote from the first central tube (3) and an outer region (421) of the side surface (42) of the upstream end (41) of the second reverse osmosis membrane group (4) remote from the second central tube (5) are sealed; and the outer region (71) of the junction (7) between the two reverse osmosis membrane modules is sealed so that concentrated water from the downstream end (21) of the first reverse osmosis membrane module (2) can flow into the upstream end (41) of the second reverse osmosis membrane module (4).

In a second aspect, the invention relates to a reverse osmosis module (module) comprising (a) a pressure vessel (8); and (b) a spiral wound reverse osmosis membrane element (1) of the invention.

These and other aspects of the invention will become more readily apparent in view of the following detailed description and examples.

Drawings

Fig. 1 is a front view of a preferred embodiment of a spiral wound reverse osmosis membrane element according to the present invention.

Fig. 2 is a cross-sectional view of the spiral wound reverse osmosis membrane element of fig. 1.

Fig. 3 is an exploded perspective view of the spiral wound reverse osmosis membrane element of fig. 1.

Fig. 4 is a front view of the side surfaces of the downstream end of the first reverse osmosis membrane module and the downstream end of the first central water collecting pipe, or the side surfaces of the upstream end of the second reverse osmosis membrane module and the upstream end of the second central water collecting pipe, as shown in fig. 3.

Fig. 5 is a front view of the connector shown in fig. 3.

Fig. 6 is a cross-sectional view of a preferred embodiment of a spiral wound reverse osmosis membrane module according to the present invention.

Fig. 7 is a front view of the treated water guide member attached to the entire central sump pipe after four adhesive tapes (glue beads) are formed.

Fig. 8 is a front view of the double folded reverse osmosis membrane after being placed on the treated water directing element of fig. 7 to provide a spiral wound reverse osmosis membrane combination (group).

FIG. 9 is a front view of the reverse osmosis membrane assembly of FIG. 8 spirally wound around the entire central collector pipe.

FIG. 10 is a front view, in cross section, of a reverse osmosis membrane assembly spirally wound around the entire central collector pipe.

Description of the symbols

1. Spiral reverse osmosis membrane element

2. The first reverse osmosis membrane group

21.2 downstream end

22.21 side surface

23.2 upstream end

24.2 outer surface

3. First central water collecting pipe

31.3 downstream end

32.3 upstream end

4. The second reverse osmosis membrane group

41.4 upstream end

42.41 side surface

43.4 downstream end

44.4 outer surface

5. Second central water collecting pipe

51.5 upstream end

52.5 downstream end

6. Connector with a locking member

61. Communicating pipe

62. Annular part

63. Rib-shaped object

7. Joint part

71.7 outer surface

8. Pressure vessel

81. Tubular container

82. Cover

83. Inlet inlet

84. Treated water outlet

85. Outlet for concentrated water

11. The whole central water collecting pipe

12. Treated water guide member

13, 14, 15, 16 adhesive tape

17. Double-folding reverse osmosis membrane

18. Reverse osmosis membrane combination of spirally wound whole central water collecting pipe

Detailed Description

Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use may optionally be understood as modified by the word "about".

It should be noted that any particular upper limit value may be combined with any particular lower limit value when specifying any range of values.

For the avoidance of doubt, the word "comprising" is intended to mean "including", but not necessarily meaning "consisting of or" consisting of. In other words, the listed steps or options are not necessarily exhaustive.

The disclosure of the invention as found herein is deemed to encompass all embodiments found in the claims as if they were multiply referenced to each other, regardless of whether in fact the claims exist in a manner that is not multiply referenced or redundant.

Where a feature is disclosed with respect to a particular aspect of the invention (e.g. the product of the invention), such disclosure is also to be regarded as applicable, mutatis mutandis, to any other aspect of the invention (e.g. the method of the invention).

Preferably, the side surface of the upstream end of the first reverse osmosis membrane module and the side surface of the downstream end of the second reverse osmosis membrane module are sealed, preferably by glue. Preferably, the longitudinal length of the first reverse osmosis membrane module is greater than the longitudinal length of the second reverse osmosis membrane module. In order to provide optimum life of the reverse osmosis element, the ratio of the longitudinal length of the first reverse osmosis membrane module to the longitudinal length of the second reverse osmosis membrane module is preferably 1: 3 to 5: 1, more preferably 1: 1 to 4: 1, even more preferably 1.2: 1 to 4: 1, most preferably from 1.5: 1 to 3: 1.

in order to provide a higher water intake rate, it is preferable that at least a portion of the outer surface of the first reverse osmosis membrane module and at least a portion of the outer surface of the second reverse osmosis membrane module are not wrapped by the plastic strip. Alternatively, the outer surfaces of the first and second reverse osmosis membrane modules are preferably wrapped with perforated plastic strips. In this way, the feed water may flow into the outer surface of the first reverse osmosis membrane module, and the concentrated water may flow out from the outer surface of the second reverse osmosis membrane module.

Preferably, the sealed outer region of the side surface of the downstream end of the first reverse osmosis membrane module and the upstream end of the second reverse osmosis membrane module is annular. Preferably, the area of the sealed portion and the area of the unsealed portion in the side surface are 1: 1 to 15: 1, preferably 2: 1 to 8: 1.

in order to improve the durability of the connected central collector pipe, a connector is used. Preferably, the connector comprises a communication tube engaging with two central water headers, preferably by frictional fastening. Preferably, the outer diameter of the communication pipe is substantially the same as the inner diameter of the central collector pipe. In this way, the communication pipe may be inserted into the inner surfaces of the two central collector pipes to ensure that the two central collector pipes are connected fluid-tightly to each other.

Preferably, the connector includes a ring portion surrounding the communication pipe and a plurality of ribs coupling (coupling) the communication pipe and the ring portion together. The concentrate water may flow through the spaces between the ribs. Preferably, the annular portion surrounds a longitudinal center of the communication pipe. Preferably, the connector includes 3 to 10 ribs coupling the communication pipe and the ring portion. Preferably, the thickness of the annular portion is substantially the same as the thickness of the rib. Preferably, the thickness of the engagement portion is substantially the same as the thickness of the annular portion. Preferably, the radius of the annular portion is substantially the same as the radius of the inner region of the side surface of the downstream end of the first reverse osmosis membrane group and the upstream end of the second reverse osmosis membrane group.

Preferably, the joint between the two reverse osmosis membrane modules is wrapped and sealed at the outer surface by a plastic strip. Therefore, the concentrated water can flow out from the inner region of the side surface of the downstream end of the first reverse osmosis membrane module and flow into the second reverse osmosis membrane module through the inner region of the side surface of the upstream end of the second reverse osmosis membrane module.

Preferably, the pressure vessel comprises a tubular vessel and a lid engaged with the tubular vessel (preferably at an upstream end of the pressure vessel). Preferably, the cap is threadedly engaged with the tubular container. Preferably, the pressure vessel comprises a feed water inlet at an upstream end of the pressure vessel, and a treated water outlet and a concentrated water outlet at a downstream end of the pressure vessel. Preferably, the water inlet is provided at the cover, more preferably in the middle of the cover.

Preferably, the downstream end of the second central collector pipe is in water-tight connection with the treated water outlet so that treated water can be discharged from the treated water outlet. Preferably, the upstream end of the first central header is sealed.

Preferably, the reverse osmosis module comprises a brine seal (brinesal) between the reverse osmosis membrane elements and the inner wall of the vessel to prevent the flow of inlet water from bypassing the elements, wherein the brine seal is provided around the junction between the two reverse osmosis membrane modules.

The invention also provides a method for preparing the spiral wound reverse osmosis membrane element. Preferably, step (i) is replaced by performing steps (a) to (d):

(a) connecting one side of the treated water flow guide member to the central collecting pipe;

(b) wrapping three substantially parallel strips of tape over the treated water flow directing element in a direction of helical winding, and one strip of tape on a side away from the central collector pipe;

(c) placing the double-folded reverse osmosis membrane on a treated water flow directing element with the folded side facing the central header to form four sealing strips to provide a reverse osmosis membrane combination, wherein an inlet water flow directing element is provided inside the treated water flow directing membrane; and

(d) optionally repeating steps (b) and (c) of providing a treatment water flow directing element.

Preferably, in step (iv), the sealing of the outer region is performed by glue. Preferably, in step (vi), the sealing of the outer region of the joint between the two reverse osmosis membrane modules is performed by winding a plastic strip around the outer surface of the joint.

Preferably, step (e) of drying the glue is carried out before step (v), preferably by natural drying.

In some embodiments, it is preferable that the step of winding the spiral wound reverse osmosis membrane on the outer surface by the plastic strip is performed before the step (iii) and the step of removing the plastic strip wound on the outer surface of the first and second reverse osmosis membrane modules. In other embodiments, it is preferred to perform the step of wrapping the spiral wound reverse osmosis membrane on the outer surface by a perforated plastic strip.

Examples

The following examples are provided in fig. 1 to 10 to facilitate understanding of the present invention. This example is not intended to limit the scope of the claims.

As shown in fig. 1, the spiral wound reverse osmosis membrane element 1 has a first reverse osmosis membrane module 2 spirally wound around a first central water collecting pipe 3 and a second reverse osmosis membrane module 4 spirally wound around a second central water collecting pipe 5. The joint 7 between the downstream end 21 of the first reverse osmosis membrane module 2 and the upstream end 41 of the second reverse osmosis membrane module 4 is wrapped at the outer surface by a plastic strip, closing and sealing at the outer surface 71 of the joint 7. The side surfaces of the upstream end 23 of the first reverse osmosis membrane module 2 and the downstream end 43 of the second reverse osmosis membrane module 4 are sealed by glue.

Each reverse osmosis membrane module comprises at least one folded reverse osmosis membrane. A feed water flow path is formed between the inner surfaces of the folded reverse osmosis membranes. A reticulated inlet flow guide element is disposed in the inlet flow passage. A treated water flow passage is formed between the outer surfaces of adjacent folded reverse osmosis membranes. A net-like treated water flow guide member is disposed in the treated water flow passage. The process water flow channel is glued on both sides in the direction of the spiral winding and on the side remote from the central process tube, so that the process water flow channel has one opening towards the central collecting tube. The central water collecting tube has a plurality of perforations to collect the treated water.

As shown in fig. 2, a connector 6 connects the first and second central headers (3, 5) together. The outer radius of the communicating pipe of the connector is matched with the inner radius of the central collector pipe so that the first collector pipe 3 is in fluid communication with the second central collector pipe 5 without leakage. The joint 7 between the two reverse osmosis membrane modules is wrapped and sealed by a plastic strip at the outer surface 71.

Fig. 3 shows an exploded view of the spiral wound reverse osmosis membrane element after removal of the plastic strip outside the joint, and fig. 4 shows a front view of the side surface of the downstream end of the first group of reverse osmosis membranes (or the side surface of the upstream end of the second group of reverse osmosis membranes, since they are substantially identical). The outer annular areas (221, 421) of the side surfaces (22, 42) of the downstream end 21 of the first reverse osmosis membrane module 2 and the upstream end 41 of the second reverse osmosis membrane module 4, which are remote from the central tubes (3, 5), are sealed by glue. The inner annular region (222, 422) adjacent to the central tube (3, 5) is unsealed. Thus, the concentrated water may flow out of the inner annular region 222 of the side surface 22 of the downstream end 21 of the first reverse osmosis membrane module 2 and into the inner annular region 422 of the side surface 42 of the upstream end 41 of the second reverse osmosis membrane module 4.

As shown in fig. 5, the connector 6 includes a communication pipe 61 fitted inside the two central header pipes, an annular portion 62 surrounding a central portion of the communication pipe 61, and four ribs 63 coupling the communication pipe and the annular portion together. Thus, the concentrated water from the downstream end of the first reverse osmosis membrane module can flow into the upstream end of the second reverse osmosis membrane module through the spaces between the ribs 63. The connector 6 also improves the mechanical durability of the connected central collector pipe.

As shown in fig. 6, the reverse osmosis module comprises a pressure vessel 8 and a spiral wound reverse osmosis membrane element 1 according to the invention. The pressure vessel 8 comprises a tubular vessel 81 and a lid 82 connected to the upstream end of the tubular vessel. The cover 82 includes a water inlet 83 in the middle of the cover 82. The tubular container 81 has a treated water outlet 84 and a concentrated water outlet 85 at the downstream end of the tubular container 81. The spiral wound reverse osmosis membrane element 1 is placed inside the tubular container 81. The side surfaces of the upstream end 23 of the first reverse osmosis membrane module 2 and the downstream end 43 of the second reverse osmosis membrane module 4 are sealed by glue. The upstream end 31 of the first central collector pipe 3 is sealed by means of glue. The downstream end 51 of the second central collector pipe 5 is connected impermeably with the treated water outlet 84. Brine seals 9 are provided around the joint 7 between the two reverse osmosis membrane modules and between the reverse osmosis membrane element 1 and the inner wall of the tubular container 81 to prevent the flow of influent water from bypassing the spiral wound reverse osmosis membrane element 1.

When the reverse osmosis module is in operation, feed water is pumped into the interior of the pressure vessel 8 through the feed water inlet 83 and pushed through the outer surface 24 of the first reverse osmosis membrane module 2 into the inside of the first reverse osmosis membrane module 2. Thus, the feed water is filtered by the first reverse osmosis membrane module 2 to produce treated water and concentrated water. The treated water flows into the interior of the first central collector pipe 3. The concentrated water flows out of the inner annular region 222 of the side surface 22 of the downstream end 21 of the first reverse osmosis membrane module 2 and enters the inner annular region 422 of the side surface 42 of the upstream end 41 of the second reverse osmosis membrane module 4. The concentrated water is filtered again by the second reverse osmosis membrane module 4 and flows out from the outer surface 44 of the second reverse osmosis membrane module 4. The treated water is discharged through the treated water outlet 84, and the concentrated water is discharged through the concentrated water outlet 85.

The water flow path is significantly increased and provides a number of benefits including increased water flow rate and improved life of the spiral wound reverse osmosis membrane elements.

Fig. 7 to 10 show how the spiral wound reverse osmosis membrane element is prepared. The first side of the net-like rectangular process water flow guiding element 12 is connected to the entire central water collecting pipe 11. Then, the first two substantially parallel adhesive strips (13, 15) are formed adjacent to the second and third sides. The third adhesive strip 14 is formed substantially parallel to the first two adhesive strips (13, 15). The third adhesive tape 14 is provided at two thirds of the treating water flow guiding member as shown in fig. 7. A fourth strip 16 is formed adjacent to the side remote from the central manifold.

The reverse osmosis membrane is then double folded and a reticulated rectangular influent flow directing element is inside the folded reverse osmosis membrane. The double-folded reverse osmosis membrane 17 is placed on the treated water flow guiding member. The water flow guide member 12 and the folded reverse osmosis membrane 17 are adhered to each other by an adhesive tape to provide a reverse osmosis membrane combination 18. The steps of providing the treated water flow guiding member, forming the adhesive tape, and adhering the folded reverse osmosis membrane to the inside of the inlet water flow guiding member are repeated again, and a second reverse osmosis membrane combination is formed on the first reverse osmosis membrane combination.

As shown in fig. 9, the reverse osmosis membrane module 18 is spirally wound around the entire central water collecting pipe 11. The spirally wound reverse osmosis membrane combination is cut along the third tape to form a first reverse osmosis membrane module 2 spirally wound around the first central water collecting pipe 3 and a second reverse osmosis membrane module 4 spirally wound around the second central water collecting pipe 5, as shown in fig. 10.

Then, outer annular regions (221, 421) of side surfaces (22, 42) of the downstream end 21 of the first reverse osmosis membrane module 2 and the upstream end 41 of the second reverse osmosis membrane module 4 are sealed by glue, as shown in fig. 4. After the glue is naturally dried and hardened, two ends of the communicating pipe of the connector are respectively inserted into the downstream end of the first central water collecting pipe and the upstream end of the second central water collecting pipe. The plastic tape is wound helically around the outer surface 71 of the joint 7 between the first and second reverse osmosis membrane modules. Thus, the concentrate from the downstream end 22 of the first reverse osmosis membrane module 2 can flow into the upstream end 42 of the second reverse osmosis membrane module 2.

The side surfaces of the upstream end 23 of the first reverse osmosis membrane module 2 and the downstream end 43 of the second reverse osmosis membrane module 4 are completely sealed by glue. The upstream end of the first central collector pipe 3 is also sealed by glue. An annular sealing element 9 is arranged outside the plastic strip and around the joint 7. The spiral wound reverse osmosis membrane element 1 is then installed into a pressure vessel 8 to produce a reverse osmosis module.

A comparative experiment was performed using the same feed water between the conventional reverse osmosis module a and the reverse osmosis module prepared in this example (referred to as E). A and E are essentially the same except that a has an integral reverse osmosis membrane that is spirally wound around the entire central treated water collector. When the flow rate of the treated water is below 150 ml/min, it is considered necessary to replace the reverse osmosis module. The life of the reverse osmosis module is the total volume of water produced at a flow rate of treated water of not less than 150 ml/min. For module a, the initial flow rate of treated water was 240 ml/min and dropped to 150 ml/min after producing a volume of 750 liters of treated water. In contrast, module E had an initial flow rate of treated water of 350 ml/min and when the flow rate of treated water dropped to 150 ml/min, 1380L of treated water was produced. Thus, a significant increase in the life of the reverse osmosis membrane element was demonstrated.

The process of the present invention requires only one reverse osmosis membrane combined with a spiral winding step to achieve a longer water flow path. Furthermore, the glue coating is easy to handle on the cut side surfaces. Therefore, the method is suitable for factory manufacturing with high efficiency and improved reliability.

Claims (12)

1. A spiral wound reverse osmosis membrane element (1) characterized by comprising:

a. a first reverse osmosis membrane group (2) spirally wound on the first central water collecting pipe (3);

b. a second reverse osmosis membrane group (4) spirally wound on the second central water collecting pipe (5); and

c. a connector (6) connecting the first central header (3) in fluid communication with the second central header (5);

wherein:

the outer region (221) of the side surface (22) of the downstream end (21) of the first reverse osmosis membrane group (2) remote from the first central water collection pipe (3) and the outer region (421) of the side surface (42) of the upstream end (41) of the second reverse osmosis membrane group (4) remote from the second central water collection pipe (5) are both sealed; and the outer region of the junction (7) between the two reverse osmosis membrane modules is sealed so that concentrated water from the downstream end (21) of the first reverse osmosis membrane module (2) can flow into the upstream end (41) of the second reverse osmosis membrane module (4).

2. Spiral wound reverse osmosis membrane element (1) according to claim 1, characterized in that the connector (6) comprises a communication pipe (61) fitting to the inside of the two central collection pipes.

3. Spiral wound reverse osmosis membrane element (1) according to claim 2, characterized in that the connector (6) comprises an annular portion (62) surrounding the communication tube (61) and a plurality of ribs (63) coupling the communication tube and the annular portion together.

4. Spiral wound reverse osmosis membrane element (1) according to any one of claims 1-3, characterized in that the first reverse osmosis membrane group (2) is longitudinally longer than the second reverse osmosis membrane group (4).

5. Spiral wound reverse osmosis membrane element (1) according to claim 4, characterized in that the ratio of the longitudinal length of the first reverse osmosis membrane group (2) to the longitudinal length of the second reverse osmosis membrane group (4) is 1.2: 1 to 4: 1.

6. spiral wound reverse osmosis membrane element (1) according to claim 4, characterized in that the ratio of the longitudinal length of the first reverse osmosis membrane group (2) to the longitudinal length of the second reverse osmosis membrane group (4) is 1.5: 1 to 3: 1.

7. spiral wound reverse osmosis membrane element (1) according to any one of claims 1-3, characterized in that the joint (7) between the two reverse osmosis membrane modules is wound and sealed by a plastic strip at the outer surface (71) of the joint.

8. Spiral wound reverse osmosis membrane element (1) according to any one of claims 1-3, characterized in that the side surface (24) of the upstream end (23) of the first reverse osmosis membrane group (2) and the side surface of the downstream end (43) of the second reverse osmosis membrane group (4) are sealed.

9. Spiral wound reverse osmosis membrane element (1) according to claim 8, characterised in that the side surface (24) of the upstream end (23) of the first reverse osmosis membrane module (2) and the side surface of the downstream end (43) of the second reverse osmosis membrane module (4) are sealed by glue.

10. A reverse osmosis module, comprising:

a. a pressure vessel (8); and

b. spiral wound reverse osmosis membrane element (1) according to any of the preceding claims.

11. The reverse osmosis module according to claim 10, characterized in that the reverse osmosis module comprises a brine seal (9) between the reverse osmosis membrane element (1) and the container to prevent the flow of incoming water from bypassing the element, wherein the brine seal (9) is provided around the junction (7) between the two groups of reverse osmosis membranes (2, 4).

12. Reverse osmosis module according to claim 10, characterized in that the pressure vessel (8) comprises an inlet for inlet water at an upstream end and an outlet for treated water and an outlet for concentrated water at a downstream end.

Images