Hollow fiber membrane module

Abstract

The present disclosure provides a structure that can enhance impact resistance when dropped. In order to realize this, a hollow fiber membrane module according to the present disclosure comprises: a cylindrical container (10) having one end and the other end that are open; a hollow fiber membrane bundle loaded in the cylindrical container (10); a potting part (30) in which the hollow fiber membrane bundle is embedded and fixed at both ends of the cylindrical container (10); and a header (40) provided at both ends in the axial direction of the cylindrical container (10). The hollow fiber membrane module is formed by welding the header (40) and the cylindrical container (10) at a welding part (50). A clearance (C) in the radial direction is formed between an outer peripheral surface (16) of the cylindrical container (10) and an inner peripheral surface (42i) of an annular side part (42) of the header (40) positioned outside the outer peripheral surface (16) in the radial direction of the cylindrical container (10). A clearance (C1) at a first position (P1) is formed wider than a clearance (C2) at a second position (P2) closer to the welding part (50) than the first position (P1) in the axial direction.

Description

Hollow fiber membrane module

[0001] The present invention relates to a hollow fiber membrane module.

[0002] Conventionally, various hollow fiber membrane blood purifiers (referred to as "hollow fiber membrane modules" in this specification) that purify blood using hollow fiber membranes loaded in a main container have been developed for extracorporeal circulation blood purification therapies such as hemodialysis, hemofiltration, plasma separation, and plasma component fractionation, and are used in many blood purification therapies that utilize membrane separation technology.

[0003] A hollow fiber membrane module is generally constructed by loading a bundle of hollow fiber membranes into a cylindrical main container (tubular container) with a port on the side, embedding and fixing the ends of the hollow fiber membrane bundle in the main container with a potting material such as urethane, and then attaching headers to both ends of the main container.

[0004] From the viewpoint of further improving the pressure-resistant welding strength between the header and the cylindrical container, a method of increasing the welding length of the welded portion has been proposed (Patent Document 1).

[0005] International Publication No. 2017 / 171015

[0006] However, there have been no hollow fiber modules that have been improved primarily to improve their strength so that they can withstand the impact of being dropped.

[0007] Therefore, an object of the present invention is to provide a hollow fiber membrane module having a structure that can improve impact resistance when dropped.

[0008] In order to solve such problems, one aspect of the present invention is a hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded into the cylindrical container; a potting section that embeds and fixes the hollow fiber membrane bundle at both end portions of the cylindrical container; and a header having a nozzle section that serves as an inlet and outlet for a fluid and provided at both axial end portions of the cylindrical container, wherein the header and the cylindrical container are welded together at a welded section, wherein a radial clearance is formed between the outer peripheral surface of the cylindrical container and the inner peripheral surface of an annular side portion of the header that is positioned outward from the outer peripheral surface in the radial direction of the cylindrical container, and the clearance at a first position is formed wider than the clearance at a second position that is closer to the welded section in the axial direction than the first position.

[0009] In the hollow fiber membrane module as described above, the welded portion may be a single welded portion formed at the contact portion between the end of the cylindrical container and the header.

[0010] In the hollow fiber membrane module as described above, the clearance may increase from the second position toward the first position.

[0011] In the hollow fiber membrane module as described above, the clearance may be gradually increased from the second position toward the first position.

[0012] In the hollow fiber membrane module as described above, the clearance may be increased stepwise from the second position toward the first position.

[0013] In the hollow fiber membrane module as described above, a small diameter portion and a large diameter portion having an inner diameter larger than that of the small diameter portion may be provided on the inner peripheral surface.

[0014] In the hollow fiber membrane module as described above, an intermediate portion may be provided between the small diameter portion and the large diameter portion, connecting the small diameter portion and the large diameter portion.

[0015] In the hollow fiber membrane module as described above, the middle part may be tapered.

[0016] In the hollow fiber membrane module as described above, the small diameter portion may be formed slightly larger than the outer diameter of the end portion of the cylindrical container so as to function as a surface for determining the relative positions of the cylindrical container and the header in the radial direction perpendicular to the central axis when the cylindrical container and the header are welded together.

[0017] In the hollow fiber membrane module as described above, the value obtained by dividing the length from the lowest end of the welded portion on the outer peripheral surface to a position on the outer peripheral surface facing the edge of the annular side portion by the clearance at a first position, which is a position on the outer peripheral surface of the end portion facing the edge, may be 0.29 or more.

[0018] In the hollow fiber membrane module as described above, the welded part may be arranged at a position other than that which is vertically above the part of the header excluding the nozzle part that is located vertically lowest at the impact point when dropped, when the hollow fiber membrane module is tilted at an angle exceeding 0°, where the central axis is parallel to the horizontal plane, but less than a predetermined angle.

[0019] In the hollow fiber membrane module described above, the predetermined angle may be the angle at which, when the hollow fiber membrane module is tilted relative to the horizontal plane, the vertical height of the lowest end position of the nozzle section or the elastic member attached to the nozzle section relative to the horizontal plane becomes equal to the vertical height of the impact point when dropped relative to the horizontal plane.

[0020] In the hollow fiber membrane module as described above, the elastic member may be a rubber plug attached to the nozzle portion.

[0021] In the hollow fiber membrane module as described above, the angle of the central axis of the hollow fiber membrane module with respect to the horizontal plane may be in the range of more than 0° and not more than 38°, and the welded parts may be arranged at positions other than those vertically above the site of impact when dropped.

[0022] In the hollow fiber membrane module as described above, the diameter of the outermost part of the header may be equal to the diameter of the outermost part of the cylindrical container.

[0023] In the hollow fiber membrane module as described above, the axial length of the outermost diameter part of the header along the central axis may be equal to the axial length of the outermost diameter part of the cylindrical container along the central axis.

[0024] In the hollow fiber membrane module as described above, the axial length of the outermost diameter part of the header along the central axis may be longer than the axial length of the outermost diameter part of the cylindrical container along the central axis.

[0025] In the hollow fiber membrane module as described above, the axial length of the outermost diameter part of the cylindrical container along the central axis may be longer than the axial length of the outermost diameter part of the header along the central axis.

[0026] Another aspect of the present invention is a hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded into the cylindrical container; a potting section that embeds and fixes the hollow fiber membrane bundle at both end portions of the cylindrical container; and headers that have nozzle sections that serve as inlets and outlets for fluids and are provided at both axial end portions of the cylindrical container, wherein a clearance sufficient to prevent contact between the outer peripheral surface of the cylindrical container and a predetermined location of the header is formed between the outer peripheral surface of the cylindrical container and the inner peripheral surface of an annular side portion of the header located outside the outer peripheral surface in the radial direction of the tubular container when the relative positions of the cylindrical container and the header change in response to an external impact acting on the header.

[0027] In the hollow fiber membrane module as described above, the welded portion may be a single welded portion formed at the contact portion between the end of the cylindrical container and the header.

[0028] In the hollow fiber membrane module as described above, the predetermined location of the header may be the edge of the inner circumferential surface of the annular side portion of the header that is most distant from the welded portion.

[0029] Yet another aspect of the present invention is a hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded in the cylindrical container; a potting section embedding and fixing the hollow fiber membrane bundle at both end portions of the cylindrical container; and headers having nozzles serving as inlets and outlets for fluids and provided at both end portions in the direction of a central axis extending in the longitudinal direction of the cylindrical container, wherein the header and the cylindrical container are welded together at welds formed at contact portions between the end portions of the cylindrical container and the header, a radial clearance is formed between the outer peripheral surface of the cylindrical container and the inner peripheral surface of an annular side portion of the header located outside the outer peripheral surface in the radial direction of the cylindrical container, the clearance at a first position is wider than the clearance at a second position axially closer to the welds than the first position, and the welds are arranged at positions excluding a position of the header that is vertically lowermost in the vertical direction and vertically above a site of impact when dropped when the hollow fiber membrane module is tilted to a predetermined angle exceeding 0° where the central axis is horizontal, This is a hollow fiber membrane module in which the diameter of the outermost part of the header is equal to the diameter of the outermost part of the cylindrical container.

[0030] According to the present invention, it is possible to improve the impact resistance performance when dropped.

[0031] 1 is a longitudinal cross-sectional view showing an example of the configuration of a hollow fiber membrane module in a position where it has been dropped from the outer periphery of the top plate portion of the header. FIG. 2 is an enlarged cross-sectional view showing an example of the configuration of the welded portion between the main container and the header and its periphery. FIG. 3 is an enlarged cross-sectional view illustrating the clearance C1 and length D at the welded portion between the main container and the header and its periphery. FIG. 4 is a longitudinal cross-sectional view showing an example of the configuration of a hollow fiber membrane module in a position where it has been dropped with the central axis A at 0°, which is horizontal. FIG. 5 is a longitudinal cross-sectional view showing an example of the configuration of a hollow fiber membrane module in which the middle portion has a more gently tapered shape. FIG. 6 is a diagram schematically showing how the header opens due to the impact acting on the welded portion when the hollow fiber membrane module is dropped. FIG. 7 is a diagram schematically showing how a hollow fiber membrane module with a predetermined clearance formed between the container and the header is dropped. FIG. 8 is a diagram schematically showing how a hollow fiber membrane module with relatively short leg portions (annular side portions) of the header is dropped. FIG. 9 is a diagram schematically showing how an impact acts on the welded portion when the hollow fiber membrane module is dropped. 1 is a diagram showing a schematic view of the legs of a header opening due to inertial force when a hollow fiber membrane module is dropped and an impact acts on a welded portion; FIG. 2 is a diagram showing a schematic view of an impact acting on a welded portion when a hollow fiber membrane module is dropped; FIG. 3 is a diagram showing a schematic view of an impact acting on a hollow fiber membrane module when it is dropped facing sideways; FIG. 4 is a diagram showing a schematic view of a cylindrical container deforming with the welded portion as a fulcrum when a hollow fiber membrane module is dropped facing sideways, in which the diameter of the outermost diameter part of the header is equal to the diameter of the outermost diameter part of the cylindrical container;

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described in detail below based on an example of an embodiment shown in the drawings (see FIG. 1, etc.).

[0033] <Configuration of hollow fiber membrane module> First, the configuration of the hollow fiber membrane module according to this embodiment will be described (see Fig. 1 etc.). The hollow fiber membrane module 1 includes a cylindrical container 10, a hollow fiber membrane bundle 20, a potting section 30, a header 40, a welding section 50, etc.

[0034] The cylindrical container 10 is formed in a cylindrical shape and has open ends 11 at both ends in the longitudinal direction (direction of the central axis A of the cylinder). A hollow fiber membrane bundle 20 is housed inside the cylindrical container 10. Two ports 14 (only one of which is shown in FIG. 1 ) are formed on the side of the cylindrical container 10, serving as inlets and outlets for fluid. In addition, an annular outer protrusion 17 is formed near the end 11, with the central axis A as its axis (see FIGS. 1 and 2A ). In this specification, the outer peripheral surface of the cylindrical container 10 in the portion from the end 11 to the outer protrusion 17 is particularly referred to as the "end outer peripheral surface" and is indicated by the reference numeral 16 (see FIG. 2A ).

[0035] The hollow fiber membrane bundle 20 is a bundle of many hollow fiber membranes, and is housed and loaded along the longitudinal direction inside the cylindrical container 10. The hollow fiber membrane bundle 20 functions as a separation membrane, and separates the components of the fluid to be separated between the inner and outer regions of each hollow fiber membrane.

[0036] The potting portion 30 is made of potting resin, and embeds both end portions 21 of the hollow fiber membrane bundle 20 inside both end portions 11 of the cylindrical container 10, and fixes the hollow fiber membrane bundle 20 to both end portions 11 of the cylindrical container 10. Examples of potting resins include polyurethane resin, epoxy resin, and silicone resin, but are not limited to these.

[0037] The header 40 is provided at the openings of both end portions 11 of the cylindrical container 10 as a lid material for these end portions 11. The header 40 has a tubular nozzle portion 45 arranged along the central axis A and serving as an inlet and outlet for the fluid, a plate-like top plate portion 46 extending radially from the nozzle portion 45, leg portions 42 protruding from the top plate portion 46 toward the cylindrical container 10, and a shoulder portion between the top plate portion 46 and the leg portions 42 (this refers to a portion including a curved surface that smoothly connects the surface of the top plate portion 46 and the circumferential surface of the leg portions 42; hereinafter, this is referred to as the "outer peripheral edge" in this specification and indicated by the symbol 46e in the drawings). Note that the surface connecting the surface of the top plate portion 46 and the circumferential surface of the leg portions 42 at the shoulder portion may have a corner.

[0038] The nozzle portion 45 has a threaded structure for connecting an external tube (not shown). The top plate portion 46 faces the end portion 21 of the hollow fiber membrane bundle 20 and has an inner surface 46a whose diameter gradually increases from the nozzle portion 45 toward the end portion 11 of the cylindrical container 10. A space 48 is formed between this inner surface 46a and the end portion 21 of the hollow fiber membrane bundle 20, through which the fluid flowing in from the nozzle portion 45 or the fluid flowing out from the nozzle portion 45 passes.

[0039] The leg portion 42 is cylindrical with the central axis A as its axis, and in a longitudinal cross-sectional view, is formed so as to extend along the central axis A toward the outer protrusion 17 of the cylindrical container 10 (see Figure 2A, etc.).

[0040] The welded portion 50 is a portion where the header 40 and the cylindrical container 10 are welded to each other. The header 40 and the cylindrical container 10 can be said to be welded by ultrasonic welding at their interference portions (e.g., an interference portion 44 on or near the inner circumferential surface 42i of the leg portion 42 of the header 40 and an interference portion 15 on or near the annular outer circumferential edge portion of the end portion 11 of the cylindrical container 10) (see FIG. 2A ). While the present embodiment illustrates a single welded portion 50 (one location in the cross-sectional view) formed at the contact portion between the end portion 11 of the cylindrical container 10 and the header 40 (see FIG. 2A , etc.), the cylindrical container 10 and the header 40 can also be welded to each other at multiple locations, although this is not specifically illustrated in the present application. The reference numeral 42o in FIG. 2A indicates the outer circumferential surface of the leg portion 42.

[0041] <Clearance Formed Between Cylindrical Container and Header> In the hollow fiber membrane module 1 of this embodiment, a predetermined radial clearance C is formed between the end outer peripheral surface 16 of the cylindrical container 10 and the inner peripheral surface 42i of the annular side portion of the leg portion 42 of the header 40, which is located outside the end outer peripheral surface 16 in the radial direction of the cylindrical container 10 (see FIG. 2A ). In the hollow fiber membrane module 1 of this embodiment, the clearance C1 at the first position P1 is wider than the clearance C2 at the second position P2, which is closer to the welded portion 50 than the first position P1 in the direction along the central axis A (see FIG. 2A ). That is, the clearance C1 and the clearance C2 have different widths. For example, the first position P1 and the second position P2 are different positions on the end outer peripheral surface 16 in the direction along the central axis A. The first position P1 may be a position facing the edge 42e (on the outermost diameter portion 19 side) of the leg portion 42 in the direction along the central axis A. In this case, the size of the clearance C (here, described as including both the first clearance C1 and the second clearance C2) is large enough to prevent contact between the end outer peripheral surface 16 of the cylindrical container 10 and a predetermined location of the header 40 even if deformation occurs in response to an external impact acting on the header 40 when the hollow fiber membrane module 1 is dropped, changing the relative position between the cylindrical container 10 and the header 40. The predetermined location of the header 40 here is not particularly limited, and may be a location that should be prevented from contacting the cylindrical container 10, for example, the edge 42e of the inner peripheral surface 42i of the leg portion (annular side portion) 42 of the header 40 that is farthest from the welded portion 50 (see FIG. 2A ).

[0042] Generally, assuming that the hollow fiber membrane module 1 is accidentally dropped to the ground or the like (indicated by the symbol G in the figure), when an external impact acts on a part of the header 40, for example, the outer peripheral edge 46e of the top plate portion 46, an external force may be exerted that changes the relative position between the cylindrical container 10 and the header 40, with the welded portion 50, which is close to the part where the impact acted, as a fulcrum (see FIG. 5 ). When the relative position between the cylindrical container 10 and the header 40 changes, the outer peripheral surface 16 of the end of the cylindrical container 10 comes into contact with a part of the header 40 (particularly problematic here is the inner peripheral surface 42i of the annular side portion, known as the leg portion 42), and at this time, a large repulsive force acts instantaneously on a narrow area, which may cause deformation or partial damage centered on the welded portion 50. In this regard, according to the hollow fiber membrane module 1 of this embodiment as described above, a clearance C sufficient to prevent contact between the end outer peripheral surface 16 of the cylindrical container 10 and part of the header 40 (particularly the inner peripheral surface 42i of the leg portion 42) is formed, so that even if an impact is applied, deformation or partial damage caused by contact between the end outer peripheral surface 16 of the cylindrical container 10 and part of the header 40 can be prevented (see FIG. 6).

[0043] As described above, from the viewpoint of avoiding contact between the outer peripheral surface 16 of the end of the cylindrical container 10 and a portion of the header 40, it is preferable that the clearance C increases from the second position P2 toward the first position P1 (see FIG. 2A). The shape or manner of the increase is not particularly limited. The clearance C may increase gradually from the second position P2 toward the first position P1, or may increase stepwise from the second position P2 toward the first position P1 (see FIG. 2A). As an example of the latter, this embodiment employs a header 40 having an inner peripheral surface 42i formed with a small-diameter portion 42a, a large-diameter portion 42c having a larger inner diameter than the small-diameter portion 42a, and an intermediate portion 42b connecting the small-diameter portion 42a and the large-diameter portion 42c (see FIG. 2A). For example, the clearance C1 at the first position P1 corresponds to the large-diameter portion 42c, and the clearance C2 at the second position P2 corresponds to the small-diameter portion 42a. A tapered intermediate portion 42b is preferable in that it functions as a guide for concentrically positioning the cylindrical container 10 and the header 40 when welding them together (see FIG. 3, etc.). The intermediate portion 42b may have a more gradual tapered shape (see FIG. 2A). The small diameter portion 42a is formed to be slightly larger than the outer diameter of the end portion 11 of the cylindrical container 10 (see FIG. 2A). The small diameter portion 42a formed in this manner can function as a surface for positioning the cylindrical container 10 and the header 40 relative to each other in the radial direction perpendicular to the central axis A when welding them together.

[0044] The clearance C or its surrounding area may have various shapes and structures as long as they are capable of preventing deformation or partial damage caused by contact between the end outer peripheral surface 16 of the cylindrical container 10 and a portion of the header 40. For example, the size of the clearance C1 is preferably 0.8 mm or more, and the size of the clearance C2 is preferably 0.2 mm or more, but these are merely preferred examples. Alternatively, the length (the length protruding in the axial direction) of the leg portions 42 of the header 40 may be shortened to make it less likely for the end outer peripheral surface 16 of the cylindrical container 10 and a portion of the header 40 to contact each other (see FIG. 7 ). In another example, the ratio (C1 / D) obtained by dividing the axial length D from the lowest welded end 50b of the welded portion 50 located vertically downward to a first position P1 on the end outer peripheral surface 16 facing the edge 42e of the leg 42 by the size of the clearance C1 from the edge 42e to the first position P1 on the end outer peripheral surface 16 facing the edge 42e may be 0.29 or greater (rounded to two decimal places) (see FIG. 2B ). That is, the ratio (C1 / D) obtained by dividing the axial length D from the lowest welded end 50b of the welded portion 50 on the outer peripheral surface 16 to the first position P1 on the outer peripheral surface 16 facing the edge 42e of the annular side portion 42 by the clearance C1 at the first position P1 on the end outer peripheral surface 16 facing the edge 42e may be 0.29 or greater. Such a ratio makes it possible to prevent deformation or partial damage caused by contact between the outer peripheral surface 16 of the end of the cylindrical container 10 and part of the header 40 .

[0045] <Positional relationship of the welded parts with respect to the outer peripheral shape of the header (see the part indicated by the symbol β in FIG. 2A )> The impact and its effects when the hollow fiber membrane module 1 is dropped can vary greatly depending on the attitude and inclination of the hollow fiber membrane module 1 at the time of the drop. For example, when the hollow fiber membrane module 1 is dropped from the outer peripheral edge 46 e of the top plate 46 of the header 40 and an external impact acts on the welded parts 50 (see FIG. 8 ), if an inertial force acts such that the legs 42 or the top plate 46 of the header 40 open (see FIG. 9 ), a great deal of stress, albeit momentarily, is generated in the welded parts 50, which are fragile parts, and this can lead to breakage. When the posture of the hollow fiber membrane module 1 when it is dropped from the outer peripheral edge 46e in this way is examined, it is found that the condition is that the central axis A is at an angle within a predetermined range with respect to the horizontal line of the ground, etc. G, in other words, that the outer peripheral edge 46e is in a predetermined posture in which it touches the ground before the nozzle portion 45 and the elastic member 45b, such as a rubber stopper, attached thereto (however, this does not take into consideration postures in which the port 14 and the elastic member 14, such as a rubber stopper, attached thereto touch the ground first). Further examination reveals that, even within this range, particularly when the part that receives the impact when dropped (in this example, the outer peripheral edge 46e) and the welded part 50 are in the same straight line (in other words, when the hollow fiber membrane module 1 is dropped in a posture in which the welded part 50 is directly above the outer peripheral edge 46e), bending deformation occurs with the impact part as a fulcrum, and therefore a greater impact acts on the welded part 50. In this case, it is believed that by adjusting the positional relationship between the outer periphery of the header 40 (particularly the outer peripheral edge 46e) and the welded portion 50 so that such a large impact does not act, it is possible to reduce the stress on the welded portion 50 and prevent damage.

[0046] In consideration of the above-mentioned considerations and events, in the hollow fiber membrane module 1 of this embodiment, the welded portion 50 is disposed at a position other than a position vertically above the lowest impact site of the header 40 (indicated by the symbol B in Figure 8 and other figures; in this example, this corresponds to the outer peripheral edge 46e of the header 40) when the hollow fiber membrane module 1 is tilted at an angle greater than 0°, where the central axis A is parallel to the horizontal plane (the surface of the ground, such as G), but less than a predetermined angle θ (see Figure 10). In this case, the predetermined angle θ can be defined as the angle at which, when the hollow fiber membrane module 1 is tilted, the vertical height of the lowest end of the nozzle portion 45 or the elastic member 45b, such as a rubber stopper, attached to the nozzle portion 45 is equal to the vertical height of the impact site B. This angle can be uniquely determined by the design of the hollow fiber membrane module. For example, if the predetermined angle θ is a value greater than 38°, such as 39°, the predetermined range of angles of the central axis A relative to the horizontal line of the ground G in this example would be, for example, an angle within the range of 0 to 38°, more specifically, an angle within the range of greater than 0° and equal to or less than 38° (see FIG. 1). In FIG. 1, the angle θ is 38°, and the nozzle portion 45 is not in contact with the ground G. In this state, the welded portion 50 is positioned in a position other than the position vertically lowermost on the header 40 that is vertically above the impact point when dropped.

[0047] <Outer diameter of header and outer diameter of tubular member (see the part indicated by the symbol Γ in Figure 2A)> Below, we will explain the hollow fiber membrane module 1 in which the diameter of the outermost diameter portion 49 of the header 40 and the diameter of the outermost diameter portion 19 of the tubular container 10 are made equal to each other to improve drop strength (see Figures 11 to 13).

[0048] Generally, assuming that the hollow fiber membrane module 1 is accidentally dropped onto the ground or the like G, when the impact surface with the ground or the like G collides with the longitudinal direction of the module (i.e., the direction along the central axis A) horizontally or at an angle close to it, if the header 40 or the cylindrical container 10 protrudes, the impact force will be concentrated on one of them, which may make them more likely to be damaged. Also, for example, if the header 40 protrudes laterally, when the impact surface with the ground or the like G collides with the longitudinal direction of the module (i.e., the direction along the central axis A) horizontally or at an angle close to it (see FIG. 11), the cylindrical container 10 may deform with the welded parts 50 as a fulcrum due to inertial force, and large stress may be generated in the welded parts 50 (see FIG. 12). In this regard, as described above, according to the hollow fiber membrane module 1 in which the diameter of the outermost diameter portion 49 of the header 40 and the diameter of the outermost diameter portion 19 of the cylindrical container 10 are equal, the header 40 and the cylindrical container 10 collide almost simultaneously, thereby dispersing the impact force and preventing the impact force from concentrating on either the header 40 or the cylindrical container 10 (see FIG. 13 ). In other words, by expanding the outer diameter of the outer protrusion 17 of the cylindrical container 10 to the extent that the outer diameter of the outer protrusion 17 becomes equal to the outer diameter of the header 40, the cylindrical container 10 can also be provided with a collision portion (convex portion) similar to that of the header 40.

[0049] In the hollow fiber membrane module 1 of this embodiment in which the diameter of the outermost diameter portion 49 of the header 40 and the diameter of the outermost diameter portion 19 of the cylindrical container 10 are made equal as described above, the axial length along the central axis A of the outermost diameter portion 49 of the header 40 (more specifically, the length of the portion of the outer edge of the header 40 that is straight in the vertical direction in the longitudinal cross section, in other words, the length of the portion that can contact the ground when the hollow fiber membrane module 1 is dropped or turned sideways in a state where the central axis A is horizontal at 0°) X ４９ is the axial length along the central axis A of the outermost diameter portion 19 of the cylindrical container 10 (more specifically, the length of the portion of the outer edge of the outer protrusion 17 of the cylindrical container 10 that is straight in the vertical direction in the longitudinal section, in other words, the length of the portion that can touch the ground when the hollow fiber membrane module 1 is dropped or turned over sideways in a state where the central axis A is horizontal at 0°), X １９2A ). However, this is merely a preferred example, and other configurations may be used. That is, although not specifically shown, the axial length X of the outermost diameter portion 49 of the header 40 along the central axis A is ４９ and the axial length X of the outermost diameter portion 19 of the cylindrical container 10 along the central axis A. １９ and the axial length X along the central axis A of the outermost diameter portion 19 of the cylindrical container 10 may be equal to each other. １９ is the axial length X of the outermost diameter portion 49 of the header 40 along the central axis A. ４９ It may be longer than

[0050] Incidentally, making the diameter of the outermost diameter portion 49 of the header 40 and the diameter of the outermost diameter portion 19 of the cylindrical container 10 equal as described above does not necessarily mean that the two dimensions must be strictly equal. As long as the impact when the hollow fiber membrane module 1 collides with the ground G or the like is dispersed and mitigated when the impact surface with the ground G or the like and the longitudinal direction of the module are horizontal or at an angle close to that, it is acceptable for the two dimensions to be strictly equal, or for there to be a slight difference between the two dimensions (for example, a difference of about ±1 mm).

[0051] While improvements have been made to the strength of hollow fiber membrane modules from the viewpoints of achieving a liquid-tight seal and increasing pressure-resistant welding strength, no improvements have been made primarily to increase the strength of the hollow fiber membrane module so that it can withstand impacts when dropped. However, in a hollow fiber membrane module 1 configured such that the header 40 and the cylindrical container 10 are joined, if the module is accidentally dropped, for example by slipping from the hand during manufacturing, transportation, or use, the impact may act on a portion of the module, causing deformation around the joint, or the header 40 may collide with the cylindrical container 10, resulting in partial damage. In this regard, the hollow fiber membrane module 1 of the present embodiment described above improves impact resistance when dropped and makes it possible to prevent deformation or partial damage caused by, for example, the outer peripheral surface of the cylindrical container 10 abutting against a portion of the header 40.

[0052] The above-described embodiment is one example of a preferred embodiment of the present invention, but the present invention is not limited to this embodiment and can be modified in various ways without departing from the spirit of the present invention.

[0053] Some or all of the above-described embodiments can be described as follows: However, the present invention is not limited to the following supplementary notes.

[0054] [Supplementary Note 1] A hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded in the cylindrical container; a potting section embedding and fixing the hollow fiber membrane bundle at both end sections of the cylindrical container; and headers having nozzle sections serving as inlets and outlets for fluids and provided at both axial end sections of the cylindrical container, wherein the headers and the cylindrical container are welded together at welded sections, wherein a clearance in the radial direction is formed between an outer peripheral surface of the cylindrical container and an inner peripheral surface of an annular side section of the header located outside the outer peripheral surface in the radial direction of the cylindrical container, and the clearance at a first position is formed wider than the clearance at a second position that is closer to the welded section in the axial direction than the first position.

[0055] [Supplementary Note 2] The hollow fiber membrane module according to Supplementary Note 1, wherein the welded portion is a single welded portion formed at a contact portion between the end of the cylindrical container and the header.

[0056] [Supplementary Note 3] The hollow fiber membrane module according to Supplementary Note 1 or 2, wherein the clearance increases from the second position toward the first position.

[0057] [Supplementary Note 4] The hollow fiber membrane module according to any one of Supplementary Notes 1 to 3, wherein the clearance gradually increases from the second position toward the first position.

[0058] [Supplementary Note 5] The hollow fiber membrane module according to any one of Supplementary Notes 1 to 3, wherein the clearance increases stepwise from the second position toward the first position.

[0059] [Appendix 6] The hollow fiber membrane module according to any one of Appendices 1 to 5, wherein the inner peripheral surface is provided with a small diameter portion and a large diameter portion having an inner diameter larger than that of the small diameter portion.

[0060] [Supplementary Note 7] The hollow fiber membrane module according to Supplementary Note 6, wherein an intermediate portion is provided between the small diameter portion and the large diameter portion, connecting the small diameter portion and the large diameter portion.

[0061] [Appendix 8] The hollow fiber membrane module according to appendix 7, wherein the intermediate portion has a tapered shape.

[0062] [Appendix 9] The hollow fiber membrane module according to Appendix 8, wherein the small diameter portion is formed to be slightly larger than the outer diameter of the end portion of the cylindrical container to such an extent that the small diameter portion functions as a surface for determining the relative positions of the cylindrical container and the header in the radial direction perpendicular to the central axis when the cylindrical container and the header are welded together.

[0063] [Appendix 10] The hollow fiber membrane module according to Appendix 9, wherein the value obtained by dividing the length from the lowest end of the welded portion on the outer peripheral surface to a position on the outer peripheral surface facing the edge of the annular side portion by the clearance at the first position, which is a position on the outer peripheral surface of the end portion facing the edge, is 0.29 or more.

[0064] [Supplementary Note 11] The hollow fiber membrane module according to Supplementary Note 2, wherein the welded portion is arranged at a position other than a position vertically above a part of the header excluding the nozzle portion that is located vertically lowest and that will be hit when dropped, when the hollow fiber membrane module is tilted at an angle exceeding 0°, where the central axis is parallel to a horizontal plane, but less than a predetermined angle.

[0065] [Appendix 12] The hollow fiber membrane module according to Appendix 11, wherein the predetermined angle is the angle at which, with the hollow fiber membrane module tilted relative to the horizontal plane, the vertical height of the lowest end position of the nozzle section or the elastic member attached to the nozzle section relative to the horizontal plane becomes equal to the vertical height of the impact point when dropped relative to the horizontal plane.

[0066] [Appendix 13] The hollow fiber membrane module according to appendix 12, wherein the elastic member is a rubber plug attached to the nozzle portion.

[0067] [Appendix 14] The hollow fiber membrane module according to Appendix 13, wherein, when the angle of the central axis of the hollow fiber membrane module with respect to the horizontal plane is in the range of more than 0° and not more than 38°, the welded portion is disposed at a position other than a position vertically above the impact site when dropped.

[0068] [Appendix 15] The hollow fiber membrane module according to any one of Appendices 1 to 14, wherein the diameter of the outermost diameter part of the header is equal to the diameter of the outermost diameter part of the cylindrical container.

[0069] [Supplementary Note 16] The hollow fiber membrane module according to Supplementary Note 15, wherein the axial length of the outermost diameter part of the header along the central axis is equal to the axial length of the outermost diameter part of the cylindrical container along the central axis.

[0070] [Supplementary Note 17] The hollow fiber membrane module according to Supplementary Note 15, wherein the axial length of the outermost diameter part of the header along the central axis is longer than the axial length of the outermost diameter part of the cylindrical container along the central axis.

[0071] [Appendix 18] The hollow fiber membrane module according to Appendix 15, wherein the axial length of the outermost diameter part of the cylindrical container along the central axis is longer than the axial length of the outermost diameter part of the header along the central axis.

[0072] [Appendix 19] A hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded in the cylindrical container; potting sections that embed and fix the hollow fiber membrane bundle at both end sections of the cylindrical container; and headers that have nozzle sections that serve as inlets and outlets for fluids and are provided at both axial end sections of the cylindrical container, wherein a clearance sufficient to prevent contact between the outer circumferential surface of the cylindrical container and a predetermined location of the header is formed between the outer circumferential surface of the cylindrical container and the inner circumferential surface of an annular side section of the header that is positioned outside the outer circumferential surface in the radial direction of the tubular container when the relative positions of the cylindrical container and the header change in response to an external impact acting on the header.

[0073] [Appendix 20] The hollow fiber membrane module according to Appendix 19, wherein the header and the cylindrical container are welded together at a welded portion, and the welded portion is a single welded portion formed at a contact site between the end of the cylindrical container and the header.

[0074] [Appendix 21] The hollow fiber membrane module according to appendix 20, wherein the predetermined location of the header is an edge portion of the inner circumferential surface of the annular side portion of the header that is most distant from the welded portion.

[0075] [Supplementary Note 22] A hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded in the cylindrical container; potting sections embedding and fixing the hollow fiber membrane bundle at both end sections of the cylindrical container; and headers having nozzle sections serving as inlets and outlets for fluids and provided at both end sections in the direction of a central axis extending in the longitudinal direction of the cylindrical container, wherein the header and the cylindrical container are welded to each other at welded sections formed at contact sections between the end sections of the cylindrical container and the header, a clearance in the radial direction is formed between the outer circumferential surface of the cylindrical container and an inner circumferential surface of an annular side section of the header located outside the outer circumferential surface in the radial direction of the cylindrical container, and the clearance at a first position is formed wider than the clearance at a second position that is closer to the welded section in the axial direction than the first position, The welded portion is arranged at a position other than a position vertically above a collision site of the header that is located vertically lowest when the hollow fiber membrane module is tilted to a predetermined angle exceeding 0°, where the central axis is horizontal, and the diameter of the outermost diameter of the header is equal to the diameter of the outermost diameter of the cylindrical container.

[0076] The present invention is suitable for application to a hollow fiber membrane module manufactured by joining a header and a cylindrical container.

[0077] DESCRIPTION OF SYMBOLS 1... Hollow fiber membrane module 10... Cylindrical container 11... End 14... Port 14b... Rubber stopper attached to port 15... Interference portion in contact with header 16... End outer peripheral surface (outer peripheral surface) 17... Outer protrusion 19... Outermost diameter portion 20... Hollow fiber membrane bundle 21... End 30... Potting portion 30a... Portion composed only of potting resin 30b... Portion where potting resin has entered into gaps between hollow fiber membranes of the hollow fiber membrane bundle 40... Header 42... Leg portion (annular side portion of header) 42a... Small diameter portion 42b... Middle portion 42c... Large diameter portion 42e... Edge portion of inner peripheral surface 42i of annular side portion that is furthest from welded portion 50 (predetermined portion of header) 42i... Inner peripheral surface of annular side portion 42o... Outer peripheral surface of annular side portion 44... Interference portion in contact with cylindrical container 45...Nozzle portion 45b...Rubber plug (elastic member) attached to the nozzle portion 46...Top plate portion 46a...Inner surface (at the top plate portion of the header) 46e...Outer edge of the top plate portion 48...Space through which fluid passes 49...Outermost diameter portion 50...Welded portion 50b...Lowest welded end portion A...Central axis B...Collision site when dropped C...Clearance C1...Clearance at first position C2...Clearance at second position G...Ground, etc. P1...First position P2...Second position X １９ ...axial length X along the central axis A of the outermost diameter portion 19 of the cylindrical container 10 ４９ ...axial length along the central axis A of the outermost diameter portion 49 of the header 40 θ...angle when the vertical height of the lowest end position of the nozzle portion or the elastic member attached to the nozzle portion becomes equal to the vertical height of the impact portion when the hollow fiber membrane module is dropped in a tilted state

Claims

1. A hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded into the cylindrical container; a potting section embedding and fixing the hollow fiber membrane bundle at both ends of the cylindrical container; and a header having a nozzle section serving as an inlet and outlet for a fluid, the header being provided at both axial ends of the cylindrical container, wherein the header and the cylindrical container are welded together at a weld section, wherein a clearance in the radial direction is formed between an outer circumferential surface of the cylindrical container and an inner circumferential surface of an annular side section of the header located outside the outer circumferential surface in the radial direction of the cylindrical container, and the clearance at a first position is formed wider than the clearance at a second position that is closer to the weld section in the axial direction than the first position.

2. The hollow fiber membrane module according to claim 1, wherein the welded portion is a single welded portion formed at the contact portion between the end of the cylindrical container and the header.

3. The hollow fiber membrane module according to claim 2, wherein the clearance increases from the second position toward the first position.

4. The hollow fiber membrane module according to claim 3, wherein the clearance gradually increases from the second position toward the first position.

5. The hollow fiber membrane module according to claim 3, wherein the clearance increases stepwise from the second position toward the first position.

6. The hollow fiber membrane module according to claim 5, wherein the inner peripheral surface is provided with a small diameter portion and a large diameter portion having an inner diameter larger than that of the small diameter portion.

7. The hollow fiber membrane module according to claim 6, wherein an intermediate portion is provided between the small diameter portion and the large diameter portion, connecting the small diameter portion and the large diameter portion.

8. The hollow fiber membrane module according to claim 7, wherein the intermediate portion is tapered.

9. A hollow fiber membrane module as described in claim 8, wherein the small diameter portion is formed slightly larger than the outer diameter of the end of the cylindrical container so as to function as a surface for determining the relative radial positions of the cylindrical container and the header perpendicular to the central axis when the cylindrical container and the header are welded together.

10. The hollow fiber membrane module described in claim 9, wherein the value obtained by dividing the length from the lowermost end of the welded portion on the outer peripheral surface to a position on the outer peripheral surface opposite the edge of the annular side portion by the clearance at the first position, which is a position on the outer peripheral surface of the end portion opposite the edge, is 0.29 or more.

11. A hollow fiber membrane module as described in claim 2, wherein the welded portion is arranged at a position other than the position vertically above the impact point when dropped that is located vertically lowest in the part of the header excluding the nozzle portion, when the hollow fiber membrane module is tilted at an angle exceeding 0°, where the central axis is horizontal to a horizontal plane, but less than a specified angle.

12. A hollow fiber membrane module as described in claim 11, wherein the specified angle is the angle at which, when the hollow fiber membrane module is tilted relative to the horizontal plane, the vertical height of the lowermost end position of the nozzle portion or the elastic member attached to the nozzle portion relative to the horizontal plane becomes equal to the vertical height of the collision point when dropped relative to the horizontal plane.

13. The hollow fiber membrane module according to claim 12, wherein the elastic member is a rubber plug attached to the nozzle portion.

14. A hollow fiber membrane module as described in claim 13, wherein when the angle of the central axis of the hollow fiber membrane module with respect to the horizontal plane is within the range of more than 0° and not more than 38°, the welded portion is positioned at a position other than a position vertically above the site of impact when dropped.

15. The hollow fiber membrane module according to claim 1, wherein the diameter of the outermost portion of the header is equal to the diameter of the outermost portion of the cylindrical container.

16. The hollow fiber membrane module according to claim 15, wherein the axial length of the outermost diameter portion of the header along the central axis is equal to the axial length of the outermost diameter portion of the cylindrical container along the central axis.

17. The hollow fiber membrane module according to claim 15, wherein the axial length of the outermost diameter portion of the header along the central axis is longer than the axial length of the outermost diameter portion of the cylindrical container along the central axis.

18. The hollow fiber membrane module according to claim 15, wherein the axial length along the central axis of the outermost diameter portion of the cylindrical container is longer than the axial length along the central axis of the outermost diameter portion of the header.

19. A hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded into the cylindrical container; a potting section embedding and fixing the hollow fiber membrane bundle at both ends of the cylindrical container; and a header having a nozzle section serving as an inlet and outlet for fluid, the header being provided at both axial ends of the cylindrical container, wherein a clearance sufficient to avoid contact between the outer circumferential surface of the cylindrical container and a predetermined portion of the header is formed between the outer circumferential surface of the cylindrical container and the inner circumferential surface of an annular side portion of the header positioned outside the outer circumferential surface in the radial direction of the tubular container when the relative positions of the cylindrical container and the header change in response to an external impact acting on the header.

20. A hollow fiber membrane module as described in claim 19, wherein the header and the cylindrical container are welded at a welded portion, the welded portion being a single welded portion formed at the contact site between the end of the cylindrical container and the header.

21. A hollow fiber membrane module as described in claim 20, wherein the specified location of the header is the edge of the inner circumferential surface of the annular side portion of the header that is furthest from the welded portion.

22. A hollow fiber membrane module comprising: a cylindrical container having one end and the other end open; a hollow fiber membrane bundle loaded in the cylindrical container; a potting section embedding and fixing the hollow fiber membrane bundle at both ends of the cylindrical container; and a header having a nozzle section serving as an inlet and outlet for a fluid and provided at both ends in a central axial direction extending in the longitudinal direction of the cylindrical container, wherein the header and the cylindrical container are welded to each other at welded sections formed at contact sites between the ends of the cylindrical container and the header, a clearance in the radial direction is formed between the outer circumferential surface of the cylindrical container and an inner circumferential surface of an annular side section of the header located outside the outer circumferential surface in the radial direction of the cylindrical container, and the clearance at a first position is formed wider than the clearance at a second position closer to the welded section in the axial direction than the first position, the welded portion is arranged at a position other than a position vertically above a site of impact when the header is dropped that is located at the lowest vertical position in the header when the hollow fiber membrane module is tilted to a predetermined angle exceeding 0°, where the central axis is horizontal, and the diameter of the outermost portion of the header is equal to the diameter of the outermost portion of the cylindrical container.

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