Australian Patents Act 1990- Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title Hollow fiber membrane module and hollow fiber membrane module unit The following statement is a full description of this invention, including the best method of performing it known to me/us: P/00/011 5102 FIELD OF THE INVENTION 5 [0001] The present invention relates to a hollow fiber membrane module for conducting filtering treatment of raw water. BACKGROUND OF THE INVENTION 10 [0002] A membrane filtration method has various advantages such as energy saving, space saving, labor saving, improvement of quality of a product and so on, and therefore, use of this method has been developed in various fields. For example, there is such a case that a precision filtering membrane or an ultrafiltering membrane is 15 applied to a water purifying process for producing industrial water or city water from river water, ground water, or sewage. [0003] Further, in a hollow fiber membrane module, it is possible to secure a large membrane area per a unit area, and therefore, the hollow fiber membrane module is 20 applied to many fluid processing fields, for example, concentration and demineralization of enzymes, production of water for parenteral solution, recovery of electro-paint, final filtration of ultrapure water, treatment of sewage or waste water, refinement of river water, lake water and undercurrent water through the ultrafiltering membrane, and refinement, dezymotization decontamination, and so on of medicines 25 through the precision filtering membrane. [0004]
IA
The hollow fiber membrane module is roughly classified into a hollow fiber membrane module of a pressurizing type and a hollow fiber membrane module of an immersion type. The hollow fiber membrane module of the pressurizing type is so constructed that a large number of porous hollow fiber membrane bundles is charged 5 into a pressure-resistant cylindrical case, both ends of the hollow fiber membrane bundle are adhesively fixed to the cylindrical case with an adhesive agent, and then, the adhesively fixed parts are cut to thereby open interiors of the hollow fiber membranes. Feed water which is pressurized is introduced into the membrane module, and filtered through membranes of the hollow fiber membranes. On the other hand, the hollow 10 fiber membrane module of the immersion type is so constructed that both ends of the hollow fiber membrane bundle are adhesively fixed with the adhesive agent respectively, and thereafter, the adhesively fixed parts are cut to thereby open the interiors of the hollow fiber membranes. This is a membrane module of a type adopting a suction filtering method in which the filtration is conducted by sucking a 15 side of filtrate. [0005] The hollow fiber membrane module of the pressurizing type has such an advantage that a filtering power can be set larger as compared with the immersion type, and a working amount per a membrane area is increased. As the results, it is possible 20 to reduce the number of the hollow fiber membranes required for the process and to minimize an installation area. [0006] Generally, as shown in Fig. 13, a hollow membrane module 1 is so constructed that lid bodies 6a, 6b respectively provided with nozzles 7a, 7b are liquid-tightly 25 engaged with both ends of a cylindrical case 3. Further, a side nozzle 5 is formed on an outer peripheral face of the cylindrical case 3 in a direction perpendicular to a 2 centerline 10 in a longitudinal direction of the cylindrical case 3. In case of filtration of an external pressure type in which the filtration is conducted from an outer peripheral membranes of the hollow fiber membranes to a radially inward direction, the pressurized feed water is introduced from the nozzle 7b of the lid body 6b at one end, 5 and filtrate which has been filtered through the hollow fiber membranes is taken out from the nozzle 7a of the lid body 6a at the other end. On the other hand, concentrate which has not been filtered and an air inside the hollow fiber membrane module 1 are discharged from the side nozzle 5. [0007] 10 Further, as shown in Fig. 16, the respective hollow fiber membrane modules 1 are individually connected to each other by means of external pipes 11 for conveying waste water which is discharged from the respective side nozzles 5, and joints (not shown). A plurality of the hollow fiber membrane modules 1 are arranged in parallel in a longitudinal direction of the external pipes 11, and formed into one operation unit t 5 in a form of a hollow fiber membrane module unit 16 to thereby conduct the membrane filtering operation. [0008] In the hollow fiber membrane module unit 16 thus formed, there has been such a problem that because the external pipes 11 and frames (not shown) for supporting the 20 external pipes are required, production cost for an entirety of the hollow fiber membrane module unit 16 is increased, and further, because the side nozzles 5 are formed in a direction perpendicular to the external pipes 11, dead spaces are created above and below the external pipes 11, which leads to a large installation area for the entirety of the hollow fiber membrane module unit 16. 25 [0009] 3 As a method for solving this problem, it is commonly known to individually attach pipes to the side nozzles of the respective hollow fiber membrane modules, and to connect the pipes to the external pipes which are provided on upper parts of the hollow fiber membrane modules. In this manner, the dead spaces in the installation 5 part can be decreased, and it is possible to minimize the installation area for the hollow fiber membrane module unit. However, in this structure too, extra installation areas for the side nozzles are required. Moreover, the external pipes are still required, and hence, predominance in respect of the production cost is not found. [0010] 10 As a method for solving the above described problems, there is disclosed means for realizing space saving of the installation area, by forming the side nozzle integrally with the lid body (Patent Document 1). Further, in this method, the side nozzle is provided at a position off-centered from a centerline of the lid body for the purpose of decreasing a pressure loss of a flow in the hollow fiber membrane module 15 and the side nozzle, and an opening area of a connection part is increased. In this manner, it has been possible to realize the space saving of the module installation area, without giving a significant pressure loss to the flow in the connection part between the hollow fiber membrane module and the side nozzle. [0011] 20 In case where the hollow fiber membrane is broken, the hollow fiber membrane does not function as the filtering membrane, and there occurs such a problem that feed water and filtrate may be mixed. In order to prevent this problem, it is necessary to repair the module, generally, by filling and sealing the open end of the hollow fiber membrane. However, in the hollow fiber membrane module disclosed in 25 Patent Document 1, the side nozzle is integrally formed with the lid body, and therefore, when the lid body is detached in a repairing work in order to fill and seal the open end 4 of this hollow fiber membrane, it is necessary to release not only the couplings between the lid bodies of the modules which are connected into a unit, but also the couplings between the side nozzles. This leads to the repairing work in a large scale. [0012] 5 Moreover, periodical maintenances of the hollow fiber membrane module are required. For example, whether or not the hollow fiber membrane is broken must be daily checked during the membrane filtering operation. However, in the hollow fiber membrane module disclosed in Patent Document 1, in which the hollow fiber membrane modules are coupled with each other, there has been such anxiety that 10 working efficiency of the maintenance work during the filtering operation is deteriorated. [0013] Patent Document 1: Japanese Patent No. 2607579 15 SUMMARY OF THE INVENTION [0014] An object of the invention is to provide a hollow fiber membrane module and a hollow fiber membrane module unit which are excellent in space saving, cost reduction, and maintenance performance, by omitting external pipes, and further, by simplifying 20 assembling members. [0015] The hollow fiber membrane module and the hollow fiber membrane module unit according to the invention for achieving the above described object are specified into the following features. 25 [0016] (1) A hollow fiber membrane module including: 5 a cylindrical case; a hollow fiber membrane bundle including a plurality of hollow fiber membranes, arranged in the cylindrical case; and lid bodies which are arranged at both ends of the cylindrical case, 5 the hollow fiber membrane bundle being adhesively fixed to the both ends of the cylindrical case in such a manner that one end or both ends of the hollow fiber membrane bundle is in an open state, in which a pair or more pairs of opposed side nozzles are formed on an outer peripheral face of the cylindrical case. 10 [0017] (2) The hollow fiber membrane module according to (1), in which a centerline of a pair of side nozzles selected from the pair or more pairs of the opposed side nozzles is perpendicular to a centerline in a longitudinal direction of the cylindrical case. [0018] 15 (3) The hollow fiber membrane module according to (2), in which the centerline of the pair of the side nozzles selected from the pair or more pairs of the opposed side nozzles is skewed with respect to the centerline in the longitudinal direction of the cylindrical case. (4) The hollow fiber membrane module according to any one of (1) to (3), in 20 which, in a longitudinal direction of the cylindrical case, an inner diameter of the cylindrical case at a position where a pair of side nozzles selected from the pair or more pairs of the opposed side nozzles are formed is larger than an inner diameter of the cylindrical case at a position where the side nozzles are not formed. [0019] 25 (5) The hollow fiber membrane module according to any one of (1) to (4), in which the lid bodies are formed of transparent material. 6 [0020] (6) A hollow fiber membrane module unit including: a plurality of the hollow fiber membrane modules according to any one of (1) to (5), coupled with each other by a pair of side nozzles selected from the pair or more 5 pairs of the opposed side nozzles. [0021] According to the invention, it is possible to provide a hollow fiber membrane module and a hollow fiber membrane module unit which are excellent in space saving and cost reduction, capable of realizing high working efficiency in maintenance work, 10 by omitting the external pipes. BRIEF DESCRIPTION OF THE DRAWING [0022] Fig. 1 is a schematic view showing an embodiment of a hollow fiber membrane 15 module according to the invention. Fig. 2 is a vertical sectional view of the hollow fiber membrane module in Fig. 1. Fig. 3 is a cross sectional view of the hollow fiber membrane module in Fig. 1, taken along a center plane of side nozzles. 20 Fig. 4 is a schematic view showing an embodiment of a hollow fiber membrane module unit (in one row) according to the invention. Fig. 5 is a schematic view showing an embodiment of a hollow fiber membrane module unit (in multiple rows) according to the invention. Fig. 6 is a schematic view showing another embodiment of the hollow fiber 25 membrane module according to the invention. 7 Fig. 7 is a cross sectional view of the hollow fiber membrane module in Fig. 6, taken along a center plane of side nozzles. Fig. 8 is a schematic view showing still another embodiment of the hollow fiber membrane module according to the invention. 5 Fig. 9 is a cross sectional view of the hollow fiber membrane module in Fig. 8, taken along a center plane of side nozzles. Fig. 10 is a schematic view showing still another embodiment of the hollow fiber membrane module according to the invention. Fig. 11 is a schematic view showing still another embodiment of the hollow 10 fiber membrane module according to the invention. Fig. 12 is a schematic view showing still another embodiment of the hollow fiber membrane module according to the invention. Fig. 13 is a schematic view showing an example of the conventional hollow fiber membrane module. [5 Fig. 14 is a vertical sectional view of the hollow fiber membrane module in Fig. 13. Fig. 15 is a cross sectional view of the hollow fiber membrane module in Fig. 13, taken along a center plane of a side nozzle. Fig. 16 is a schematic view showing an example of the conventional hollow 20 fiber membrane module unit. DETAILED DESCRIPTION OF THE INVENTION [0023] Now, the invention will be described referring to the drawings schematically 25 showing a best mode for carrying out the invention. However, a scope of the invention is not limited to the drawings. 8 [0024] An embodiment of a hollow fiber membrane module 1 of a pressurizing type according to the invention is shown in Fig. 1, and a vertical sectional view thereof is shown in Fig. 2. The hollow fiber membrane module 1 is so constructed that a hollow 5 fiber membrane bundle 2 including several hundreds to several ten thousands of the hollow fiber membranes which are bundled is charged into a pressure-resistant cylindrical case 3, and both ends of the hollow fiber membrane bundle 2 are adhesively fixed with adhesive agent 4. In the hollow fiber membrane module 1 in Fig. 1, an adhesively fixed part at one end is adhesively fixed in a state where end faces of the 10 hollow fiber membranes are opened, and an adhesively fixed part at the other end is adhesively fixed in a state where end faces of the hollow fiber membranes are closed. However, it is also possible to use the hollow fiber membrane module of such a type that the adhesively fixed parts at both ends are adhesively fixed in a state where the end faces of the hollow fiber membranes are opened. 15 [0025] As a method for rendering the end faces of the hollow fiber membranes to be opened, any known method can be adopted. For example, there is such a method that in a state where open parts (or hollow parts) at the ends of the hollow fiber membranes are sealed in advance with the adhesive agent or the like, and a fluidal resin is 20 introduced between a plurality of the hollow fiber membranes and hardened to thereby form the adhesively fixed parts, and then, the adhesively fixed parts and sealed parts at the ends of the hollow fiber membranes are cut to thereby expose the open parts. [0026] Moreover, the hollow fiber membrane module 1 may be vertically arranged to 25 conduct membrane filtering operation, that is, the membrane filtering operation may be conducted, by arranging the adhesively fixed parts at the both ends in a substantially 9 vertical direction. Alternatively, the hollow fiber membrane module 1 may be horizontally arranged, that is, the membrane filtering operation may be conducted, by arranging the adhesively fixed parts at the both ends in a substantially horizontal direction. However, the operation in the vertical arrangement is more preferable, 5 because an amount of air which is required for air scrubbing (cleaning of the membranes with air) is smaller in this case. [0027] Material for the cylindrical case 3 is not particularly limited. However, considering productivity, cost and weight reduction, and further, considering chemical 10 resistance with respect to various substances contained in the feed water, and weather resistance on the assumption of outdoor uses, the material is usually selected from resin such as polyvinyl chloride (PVC), acrylonitrile-butadiene-stylene copolymer (ABS), and their composite material (polymer alloy or the like). [0028] 15 The hollow fiber membrane is not particularly limited, provided that it is a porous hollow fiber membrane. However, the hollow fiber membrane is preferably formed of organic material such as polyvinylidene fluoride (PVDF), polypropylene (PP), polyethylene (PE) and polyethersulfone (PES) or inorganic material such as ceramics. Further, in view of strength of the membrane, the hollow fiber membrane 20 formed of polyvinylidene fluoride (PVDF) is more preferable. A pore diameter on a surface of the hollow fiber membrane is not particularly limited, but can be adequately selected from a range of 0.00 1 km to 1 km. Moreover, an outer diameter of the hollow fiber membrane is not particularly limited, but may be preferably selected from a range of 250 gm to 2000 pim, because swinging performance of the hollow fiber membrane is 25 high, and cleaning ability is excellent in this range. [0029] 10 The adhesive agent 4 for adhesively fixing the both ends of the hollow fiber membrane bundle 2 to the cylindrical case 3 is not particularly limited, but thermosetting resin such as epoxy resin, urethane resin is preferably used. [0030] 5 The hollow fiber membrane module 1 according to the invention is characterized in that a pair or more pairs of side nozzles 5 which are opposed to each other are formed on an outer peripheral face of the cylindrical case 3, as shown in Fig. 1. In the embodiment as shown in Fig. 1, a centerline 9 of the pair of the opposed side nozzles 5 is perpendicular to a centerline 10 in a longitudinal direction of the cylindrical 10 case 3. A cross sectional view taken along a center plane of the side nozzles 5 is shown in Fig. 3. [0031] Since the pair or more pairs of the side nozzles 5 which are opposed to each other are formed on the outer peripheral face of the cylindrical case 3, it is possible to 15 form a hollow fiber membrane module unit in one row, as shown in Fig. 4, by coupling a plurality of the hollow fiber membrane modules 1 by the pair of the side nozzles 5 which are selected from the pair or more pairs of the opposed side nozzles. Therefore, the external pipes which have individually connected the respective hollow fiber membrane modules in the conventional case can be omitted. For coupling the side 20 nozzles 5 to each other, a joint 12 in a shape of a clamp or so may be used, in the same manner as in case of coupling the side nozzle to the external pipe in the conventional case. [0032] Further, as shown in Fig. 5, a hollow fiber membrane module unit 16 in 25 multiple rows is formed by arranging a number of the hollow fiber membrane module units in one row in parallel with each other in a direction perpendicular to the one row, 11 by connecting a water collecting pipe 15 to respective openings of the side nozzles 5 of the hollow fiber membrane modules 1 which are coupled to terminal ends at one side in the respective rows, and by liquid-tightly closing the respective openings of the side nozzles 5 of the hollow fiber membrane modules 1 which are connected to terminal 5 ends at the other side. In a feature of the conventional hollow fiber membrane module unit, the hollow fiber membrane module units 16 in two rows are basically formed, by arranging the hollow fiber membrane modules 1 at both sides of the external pipe 11, and by individually coupling them by the respective side nozzles 5, as shown in Fig. 16 (in Fig. 16, there are shown two sets of the hollow fiber membrane module units 16 in 10 two rows). However, in the embodiment of the present invention, a constituent unit of the hollow fiber membrane module unit 16 is basically one row, and therefore, it is possible to design the hollow fiber membrane module unit 16 with higher freeness. [0033] Now, a filtering mechanism employing the hollow fiber membrane modules 1 15 according to the invention will be described referring to the filtration of an external pressure type which is directed to radially inwardly from outer membrane faces of the hollow fiber membranes. In this case, as shown in Fig. 3, concentrate which has not been filtered through the respective hollow fiber membrane modules 1, and the air inside the hollow fiber membrane modules 1 are discharged from the side nozzles 5. 20 However, because the respective side nozzles 5 of the hollow fiber membrane modules I are coupled with each other, the water and the air are continuously discharged, while repeating flowing into the hollow fiber membrane modules 1 at a downstream side (toward the water collecting pipe 15), passing through a gap 13 between an inner peripheral face of the cylindrical case 3 and the hollow fiber membrane bundle 2 and 25 merging, and flowing into the hollow fiber membrane module at the downstream side. [0034] 12 As the results, an amount of the water flowing through the side nozzles 5 is increased in a downstream direction, and for this reason, an inner diameter of the side nozzle 5 must be such an inner diameter as meeting to the amount of the water corresponding to the number of the coupled hollow fiber membrane modules 1. 5 Generally, when the number of the coupled hollow fiber membrane modules 1 is N, the inner diameter of the side nozzle 5 is preferably TN times of the inner diameter of the conventional side nozzle. [0035] In this invention, such an embodiment that the centerline 9 of a pair of side 10 nozzles 5 selected from the pair or more pairs of the opposed side nozzles is perpendicular to the centerline 10 in the longitudinal direction of the cylindrical case 3 is preferable. Particularly preferably, there is such an embodiment that the centerline 9 of the pair of the opposed side nozzles is perpendicular to and skewed with respect to the centerline 10 in the longitudinal direction of the cylindrical case 3, as shown, for 15 example, in Fig. 6 or 7. Herein, the centerlines of the side nozzles and the cylindrical case mean a rectilinear line which longitudinally connects respective centers of desired sectional planes which are perpendicular to the longitudinal direction. The term "perpendicular" indicates that two rectilinear lines are at a right angle, and at the same time, does not always mean that the two rectilinear lines intersect, in all cases. 20 Further, the term "skewed" means positional relation between two rectilinear lines, when the two rectilinear lines in a space are not in parallel and do not intersect, that is, when the two rectilinear lines do not exist in the same plane. This indicates that the side nozzles 5 are offset in a horizontal direction, as seen from the opening of the side nozzle 5. 25 [0036] 13 In this embodiment, it is possible to decrease a pressure loss of the flow inside the side nozzles 5 and the cylindrical case 3, as compared with an embodiment in which the centerline 9 of a pair of the opposed side nozzles 5 is perpendicular to the centerline 10 in the longitudinal direction of the cylindrical case 3. On the other hand, in the 5 embodiment where the centerline 9 of a pair of the opposed side nozzles 5 is perpendicular to the centerline 10 in the longitudinal direction of the cylindrical case 3, the cylindrical case 3 and the side nozzles 5 become compact and simple in shape, and molding cost can be reduced. [0037] 10 In the hollow fiber membrane module according to the invention, the relation between the centerline 9 of a pair of the opposed side nozzles 5 and the centerline 10 in the longitudinal direction of the cylindrical case 3 may be appropriately determined according to required functions. [0038] 15 Moreover, in the invention, it is preferable that the inner diameter of the cylindrical case 3 at a position where a pair of side nozzles 5 selected from the pair or more pairs of the opposed side nozzles are formed is larger than the inner diameter thereof at a position where the side nozzles are not formed, as shown in Fig. 8 or 9. In this embodiment, the gap 13 between the inner peripheral face of the cylindrical case 3 20 and the hollow fiber membrane bundle 2 can be enlarged, and so, it is possible to decrease the pressure loss of the flow inside the cylindrical case 3, as compared with an embodiment where the inner diameter of the cylindrical case 3 is constant. [0039] Further, the side nozzle and the lid body may be preferably composed of 25 separate members. In case where the hollow fiber membrane is broken, the hollow fiber membrane does not function as the filtering membrane, and there occurs such a 14 problem that feed water and filtrate may be mixed. In order to prevent this problem, it is necessary to repair the module by filling and sealing the open end of the hollow fiber membrane which is broken. In case where the side nozzle and the lid body are composed of the separate members, working efficiency of the maintenance work during 5 the filtering operation is enhanced. [0040] Therefore, it is preferable that the lid body can be easily attached or detached, and connected in a liquid-tightly sealed state for preventing a leak of the inner liquid. As connecting means for achieving this, there are various methods, for example, screw 10 connection, clamp connection, and flange connection. [0041] As one of means for easily confirming, during the maintenance, whether or not the hollow fiber membrane is broken, the lid body is preferably formed of transparent material. In this manner, it is possible to visually confirm whether or not the hollow 15 fiber membrane is broken, even during the filtering operation, without removing the lid body. The transparent material for the lid body is not particularly limited, provided that the material is such that condition of the fluid flowing inside the lid body can be seen from the exterior. For example, resin such as polyvinyl chloride (PVC), acrylic resin, or polycarbonate of transparent type is recommended. 20 [0042] Moreover, a pair or more pairs of the side nozzles need not be necessarily formed on the outer peripheral face of the cylindrical case. For example, as shown in Fig. 10, a cylindrical body 8 provided with a pair or more pairs of the side nozzles 5 on its outer peripheral face may be liquid-tightly engaged with the cylindrical case 3. 25 [0043] 15 Further, according to the invention, the number of the opposed side nozzles are not limited to one pair, but may be two or more pairs. The embodiments having two or more pairs of the opposed side nozzles are shown in Figs. 11 and 12. [0044] 5 As described above, in the hollow fiber membrane module according to the invention, since the side nozzles function also as pipelines, the external pipes can be omitted. Therefore, it is possible to reduce the production cost for the entirety of the hollow fiber membrane module unit. Further, it is possible to achieve space saving, by decreasing the installation area of the hollow fiber membrane module unit, and at the 10 same time, it is possible to obtain high maintenance performance, by simplifying shapes of the assembling members. Moreover, in producing the hollow fiber membrane module according to the invention, the substantially same working method as the conventional working method can be applied, and it is possible to easily adopt the conventional working method, because the other constituent members including the lid 15 body and so on need not be modified. Description of Reference Numerals and Signs [0045] 1 Hollow fiber membrane module 20 2 Hollow fiber membrane bundle 3 Cylindrical case 4 Adhesive agent 5 Side nozzle 6a, 6b Lid body 25 7a, 7b Nozzle 8 Cylindrical body 16 9 Centerline of side nozzle 10 Centerline in a longitudinal direction of cylindrical case 11 External pipe 12 Joint 5 13 Gap between inner peripheral face of cylindrical case and hollow fiber membrane bundle 14 Flow of water inside hollow fiber membrane module 15 Water collecting pipe 16 Hollow fiber membrane module unit 17 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 18