JPH0257981B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a module used in a hollow fiber type reverse osmosis device, and more specifically, the present invention relates to a method for manufacturing a module used in a hollow fiber type reverse osmosis device, and in particular, a method for uniformly flowing raw water without uneven flow and without concentration polarization. The present invention relates to a method for efficiently manufacturing a hollow fiber type reverse osmosis module with a high salt rejection rate.

[Prior Art] Recently, reverse osmosis devices have come into use for desalination of seawater, desalination of brackish water, or production of pure water. There are three types of reverse osmosis devices: tubular type, spiral type, and hollow fiber type.The hollow fiber type has a smaller permeation flow rate per unit membrane area than other types, but it has a larger surface area, so the overall It has the advantage of significantly increasing the permeation flow rate and extremely high volumetric efficiency, so it has come to be widely adopted.

By the way, such a hollow fiber type reverse osmosis module is constructed by arranging one or more membrane assemblies (elements) each formed in a bundle of a large number of hollow fibers in a single or double row within a pressure vessel. be done. FIG. 9 is a structural explanatory diagram showing an example of this hollow fiber type reverse osmosis module, and shows a single element type.
In other words, 1 is a pressure vessel with lid plates 2 and 2 on both sides respectively.
3 and configure. As shown in FIG. 10, a flow cylinder 8 formed of a perforated cylinder is placed in the center of the element 4 placed inside the pressure vessel 1.
A large number of hollow fibers 5 are arranged in a bundle around it. The hollow fiber 5 is bent into a U-shape at the end, and the opening 5a side thereof is embedded in the resin flange part 7 together with the flow cylinder 8, and the opening 5a of the hollow fiber 5 is exposed on the outer peripheral surface of the flange part 7. . Further, the bent end side of the hollow fiber bent into a U-shape is also formed by a resin flange portion 6. Further, the flange portion 6 has a smaller outer diameter than the flange portion 7 on the other opening side. When disposed within the pressure vessel 1, a ring packing 7a is arranged around the outer periphery of the flange portion 7 to ensure a watertight arrangement. On the other hand, the flange portion 6 of the element 4
A raw water introduction pipe 9 is connected to the side, and the pipe 9
are connected so as to pass through the cover plate 2, and the element 4
It opens into the flow cylinder 8 of. Further, a cavity 11 is formed outside the flange portion 7 of the element 4 in the pressure vessel 1, and the cavity 11 serves as a reservoir for manufactured water. A manufactured water take-out pipe 12 is provided on the cover plate 3 and communicates with the cavity 11. Further, a concentrated water take-off pipe 10 is connected to the outer periphery of the pressure vessel 1, and the pipe 10 is provided with a suitable on-off valve device. When producing water, the raw water is pumped into the flow cylinder 8 of the element 4 through the introduction pipe 9, and the produced water that has permeated through the membrane of the hollow fibers 5 flows through the hollow fibers of the flange portion 7. It flows into the reservoir 11 through the opening 5a and is taken out from the takeout pipe 12. On the other hand, the raw water that could not be permeated becomes concentrated water and is taken out from the takeout pipe 10, and the raw water permeates the element 4 while moving from the center side to the outer peripheral side. On the other hand, raw water may be introduced from the outer circumferential side of the element 4 and penetrate while moving toward the flow cylinder 8 side, and the production water can be taken out in the same way as the opening 5a of the flange part 7, but the concentrated water will be taken out from one side of the flow cylinder 8.

[Problems to be Solved by the Invention] By the way, regarding the arrangement of the hollow fibers 5 constituting the element 4, it is possible to increase the permeable membrane formation area by arranging a large number of fibers, without obstructing the passage of raw water. Moreover, it is required that they be arranged so as to allow uniform passage, and that they be easy to arrange and construct. Also hollow fiber 5
The fact that the fiber length corresponds to the area of the opening 5a also influences the penetration efficiency. Further, these hollow fibers 5 need to be arranged so as to have a uniform density in the package constituting the element 4.
Figure 10 shows an example of element 4.
The hollow fibers 5 are arranged around the outer periphery of the flow cylinder 8 so as to have approximately the length of the element, and the periphery of the hollow fibers 5 is wrapped with a binding thread 5b.
The density is too high, and it takes time to mold the package, resulting in poor manufacturing efficiency. From these, it is known to form a package by traversing a single fiber like a general thread-wound package, or by traversing a bundle, but there is a method of simply winding a hollow fiber bundle around the flow cylinder 8. In the module manufactured by the above, when the fluid is guided from the flow cylinder 8 toward the outer circumference, the fluid does not flow uniformly as expected, and drift tends to occur. Therefore, in such a module, the amount of fluid that permeates is small, and it is difficult to obtain high separation efficiency due to the concentration polarization of non-permeable components of the liquid to be treated. Further, when the distance to the open end of the hollow fiber 5 wound as the element 4 constituting the module is increased, the transmittance decreases due to the pressure of the permeated liquid inside the hollow fiber. When forming element packages from these elements, it has been desired to develop a method for easily manufacturing elements that meet the above-mentioned requirements.

Therefore, the present invention has been made based on the above, and an object thereof is to provide a method for efficiently manufacturing an element of a hollow fiber type reverse osmosis module that can perform uniform infiltration.

[Means for Solving the Problems] However, the method for manufacturing such a hollow fiber type reverse osmosis module is to collect a large number of single hollow fibers and pass them through a single circular hole to form a group of fibers with a circular cross section. Furthermore, a plurality of the fiber groups are connected and sequentially wound around the flow cylinder as a fiber bundle with a flat cross-section, and this winding is done at a constant angle of 5 to 60 degrees with respect to the axis of the flow cylinder. The fiber bundles in the same helical direction are wound parallel to and adjacent to the previously wound fiber bundle, or the side edges overlap each other, and the opposite The fiber bundles in the helical direction are wound so as to alternately overlap to form an intersection, and the intersection is formed at a fixed position of the winding circulation cylinder and sequentially moves on the same circumference, and the intersection is In this method, parallel fiber bundles form layers, and layers formed by fiber bundles in the opposite direction are alternately laminated.

[Function and Examples] Typical embodiments of the present invention will be described below.

FIG. 1 is a plan view showing the entire winding device used in the method of the present invention, and FIG. 2 is a sectional view taken along the cutting line A-A in FIG. The flow cylinder 8 is held by a driving device as a winding core. The drive device includes a drive unit 1
4, and a support device 13 provided opposite to the drive shaft 14a, the support device is provided so that the flow cylinder 8 can be protruded from and retracted from the drive shaft 14a and the support device 13. It is held between the shafts 13a. The speed of the drive shaft 14a is controlled via a transmission 14b, and the support shaft 13a freely rotates to rotate the flow cylinder 8. On the other hand, the traverse device 15 is provided with two fixed guide rods 16, 16 at the top and bottom, and a guide bracket 18 is slidably provided on the rods 16, 16. A guide 17 is also attached to the top of the guide bracket 18. An endless chain 19 is stretched between the rods 16 and on the back side (supply side) and rotated, and the rotation is performed at a constant speed by a drive device 20. 21 is a support member. An engaging member provided with a protrusion is fixed to a part of the chain 19, and this engaging member is attached to the guide bracket 1.
8. Engage with the longitudinal groove formed in 8. The rotation of the chain 19 thus causes the guide bracket 18 to traverse along the guide rods 16,16. A guide bar 24 guides the assembled fiber group 22 drawn out from the fiber storage container 23. During the winding drive, the speed on the winding core side is gradually reduced so that the intersection 25 is formed at a substantially constant position. Note that the winding device used in the present invention is not limited to the above embodiment, and other devices may also be used.

A method for winding up elements of a hollow fiber type reverse osmosis module using the winding device described above will be described in detail below. FIG. 8 is a schematic side view of an element 4a according to the present invention, partially cut away. Figure 5 is an enlarged explanatory diagram of the winding body shown in Figure 1;
The figure is an explanatory diagram of winding. In these figures, the element 4a constituting the hollow fiber type reverse osmosis module is traversed back and forth as shown in FIG. Wind it up. In addition, when winding and traversing, the hollow fiber 5 collects 10 to 30 single fibers and passes them through a circular single hole 17a (see FIG. 3) to form one fiber group 22. A plurality of fibers are bundled so as to be connected in a horizontal direction, and wound around the flow cylinder 8 as a fiber bundle 22a having a uniform fiber density and a flat cross section. That is, the guy 17 for guiding these fibers is constructed by arranging three single holes 17a in a horizontal row as shown in FIG. 3, and a group of hollow fiber fibers 22 is used by gathering them together as shown in FIG. 4. Therefore, the guide 17
The fiber bundle 22a drawn out from the fiber bundle 22a has a flat cross-sectional shape, and its both sides are thin.
Furthermore, these both sides tend to be thicker on one side and thinner on the other side depending on the traverse direction. When winding the fiber bundles 22a around the flow cylinder while traversing them, these fiber bundles 22a are stacked one after another so that those in the same helical direction are adjacent to each other, or so that their both end edges overlap each other. go. A portion of the cutting line BB in FIG. 5 is shown in FIG. 6. In this example, the fiber bundles 22a are wound in parallel so as to be adjacent to each other, and are wound in layers in sequence. Further, the intersection portion 25 is formed on the circumference at a substantially specific position in the longitudinal direction of the flow cylinder 8, as schematically shown in FIG. In the element 4 wound in this manner, the filament bundles 22a wound crosswise with each other are adjacent in parallel to the filament bundles wound in the same helical direction immediately before (the side portions of the filament bundles 22a). When stacking fiber bundles, the side edges overlap and are stacked in layers), and the intersections formed by the successively wound fiber bundles are formed at approximately a constant length distance from the previous intersections. , the intersections are also formed sequentially in the circumferential direction of the flow cylinder in the same manner as described above.

The element manufactured in the above manner is produced by collecting a large number of single fibers and winding them as a flat fiber bundle as described above, and by winding the intersection of the spiral traverses at a fixed position in the winding length direction and also on the circumference. Since it is formed by sequentially moving to , it can be formed as follows. In other words, the permselective hollow fibers form layers arranged in parallel with a constant thickness, and are regularly stacked alternately with layers formed by fibers in the opposite helical direction. The fluid passing through it flows uniformly without creating polarized currents, and it has become possible to achieve high permeation and high separation performance without concentration polarization. In addition,
Forming the intersections of fiber bundles at specific positions and sequentially on the circumference means that at first glance, the fiber density at the overlapped intersections is higher than at the other parts, and low-density areas are formed in the vicinity of the intersections. It is thought that the raw water forms a passage group, but in reality, as described above, the raw water flows uniformly without causing any uneven flow. The reason for this is that the number of fibers in the thickness direction constituting the element is the same in all parts, and as long as the element is cylindrical, the overall density is uniform.

In addition, variations in density are actively formed at the intersections, and some raw water at a constant pressure flows toward the center in the thickness direction through these rough areas, resulting in the following effect.

In other words, in the above-mentioned homogeneous part, the more it penetrates toward the center,
The raw water is concentrated and its ability to permeate has decreased, and the hollow fibers on the center side are exposed to concentrated liquid with low permeability and are no longer able to effectively permeate. In the vicinity of the filament, a low-density part is formed, and unconcentrated raw water (with excellent permeation ability) can be sent to the center, so this raw water also permeates in the helical direction of the filament bundle. It is conceivable that the permeation treatment occurs in the homogeneous region, and no concentration polarization is created. Therefore, the hollow fiber type reverse osmosis module produced by the method of the present invention can have elements with a large diameter and a thick layer, and can have excellent throughput.

[Effects of the Invention] The element manufactured according to the present invention can substantially equalize the fiber density and make the permeability of raw water uniform, and the flow direction thereof is uniform in a radial direction, with no polarization and no concentration polarization. It became possible to obtain modules with excellent permeability, and in particular, hollow fiber type reverse osmosis modules for desalination of seawater with improved salt rejection rates.

[Brief explanation of the drawing]

Fig. 1 is an explanatory plan view showing an example of a winding device used in the method of the present invention, Fig. 2 is an explanatory cross-sectional view taken along line A-A in Fig. 1, Fig. 3 is a side view of the traverse guide, and Fig. 4 5 is a partially broken explanatory diagram showing a wound element molded body, FIG. 6 is a partial cross-sectional view taken along line B-B in FIG. 5, and FIG. 8 is an explanatory view showing an example of winding and forming, FIG. 8 is a partially cutaway front view of an element manufactured by the present invention, FIG. 9 is an explanatory cross-sectional view showing a conventional example of a hollow fiber type reverse osmosis module, and FIG. 10 11 is a partially cutaway side view showing a conventional element, and FIG. 11 is a right side view of FIG. 10. DESCRIPTION OF SYMBOLS 1... Pressure vessel, 2, 3... Lid plate, 4... Element, 5... Hollow fiber, 6, 7... Resin flange part, 8... Distribution cylinder, 9... Introductory pipe, 10
...Concentrated water extraction pipe, 11...Reservoir, 12...
Manufactured water extraction pipe, 13... Support device, 14...
Drive device, 15... Traverse device, 16... Guide rod, 17... Guide, 18... Guide bracket, 19... Chain, 20... Drive device, 21... Support member, 22a... Fiber bundle, 24
...Guide bar, 25...Intersection.

Claims (1)

[Claims] 1. In a method for manufacturing a hollow fiber type reverse osmosis module in which a large number of hollow fibers are laminated around the outer periphery of a perforated flow cylinder, a large number of single fibers of the hollow fibers are collected and passed through a circular single hole to form a fiber with a circular cross section. a group of fibers, and a plurality of fiber groups are laterally connected to form a bundle of fibers with a flat cross section, and the fibers are wound in a reciprocating traverse at a helical angle within a range of 5 to 60 degrees with respect to the axis of the flow cylinder; Filament bundles in the same helical direction are arranged parallel to and adjacent to the fiber bundle wound immediately before, or so that their side edges overlap each other, while fiber bundles in the opposite helical direction are arranged in an alternating manner. overlap to form intersections, and the intersections are formed sequentially on the same circumference at certain positions of the winding circulation cylinder, and layers are formed by parallel fiber bundles at positions other than the intersections. A method for manufacturing a hollow fiber reverse osmosis module, characterized in that fiber bundles having different helical directions are laminated alternately in the thickness direction.