Hollow fiber module

Abstract

The utility model discloses a hollow fiber module which comprises a hollow fiber membrane bundle and a container, the hollow fiber membrane bundle comprises a plurality of hollow fiber membrane filaments and two potting parts for constraining first ends and second ends of the hollow fiber membrane filaments, which are axially opposite to each other; the first inner core surrounds the first ends of the hollow fiber membrane filaments, the first inner core is fixed relative to the container and is provided with a first circulation section corresponding to the first liquid passing opening, and a plurality of circulation holes are distributed in the first circulation section; a non-porous first solid section is formed at one end, far away from the corresponding filling and sealing part, of the first circulating section of the first inner core, and the minimum distance between the first circulating section and the second ends of the plurality of hollow fiber membrane filaments is greater than the minimum distance between the first liquid passing opening and the second ends of the plurality of hollow fiber membrane filaments. No matter the first liquid passing port is used as a liquid inlet or a liquid outlet, the longer first entity section on the first inner core has the beneficial effects that the junction of the membrane filament on the outer ring and the filling and sealing part is prevented from being damaged, or the overall filtering efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to filter technical field, especially a kind of hollow fiber module. BACKGROUND

[0002] The hollow fiber membrane module in prior art has more application scenarios, and can realize the functions of filtering and concentrating. The outer pressure type hollow fiber membrane module is commonly used for ultra-pure water filtration. Figure 1 As shown in the accompanying drawings, the existing outer pressure type hollow fiber membrane module includes a shell and a hollow fiber membrane bundle axially fixed in the shell. The shell includes two nozzles located at both ends of the side wall and a filtrate outlet provided at the axial end. One of the nozzles serves as a raw liquid inlet, and the other nozzle serves as a concentrated water outlet. Clean filtrate is discharged from the filtrate outlet.

[0003] Both ends of the membrane bundle are sealed and fixed to the inner wall of the shell by pouring sealant, and at least one end of the membrane bundle is open for discharging filtrate. In addition, to protect the hollow fiber membrane filaments, the nozzle corresponding to the side wall at the end of the membrane bundle is wrapped by a flow straightening cylinder. Generally, one end of the flow straightening cylinder is inserted into the pouring sealant together with the hollow fiber membrane filaments, and the other end is fixed by clamping with the shell. The area of the flow straightening cylinder exposed to the outside of the pouring sealant and staggered with the nozzle is provided with a plurality of flow-through holes to allow raw liquid to flow into the flow straightening cylinder and concentrated water in the flow straightening cylinder to flow out. The nozzle area of the flow straightening cylinder directly opposite the shell is not provided with flow-through holes to avoid direct impact of raw liquid on the membrane filaments, so as to protect both ends of the hollow fiber membrane bundle. There is a gap between the flow straightening cylinder and the inner wall of the shell to form a flow channel, so that the shell is filled with liquid, all areas of the membrane filaments are fully utilized, and a relatively high filtration rate is provided.

[0004] The liquid to be filtered flows into the raw liquid inlet, reaches the outside of the membrane filaments, and the particulate impurities are trapped. The filtrate passes through the side wall of the membrane filaments into the inside of the membrane filaments, and then is discharged from the filtrate outlet. The concentrated water remaining on the outside of the membrane filaments is discharged from the concentrated water outlet.

[0005] In use, the hollow fiber membrane module is generally placed axially, the nozzle located at the upper part is used for liquid outlet, and the nozzle located at the lower part is used for liquid inlet. The liquid to be filtered flows into the lower nozzle, and the liquid level in the shell gradually rises to exhaust the gas in the shell and the hollow fiber membrane filaments to avoid air resistance. However, the existing outer pressure type hollow fiber membrane module has some problems:

[0006] Based on the placement mode of the hollow fiber membrane module, the to-be-filtered liquid flows in from the raw liquid inlet, part of the to-be-filtered liquid flows into the straightening cylinder through the flow-through hole, the rest of the to-be-filtered liquid is contained between the outer periphery of the straightening cylinder and the inner wall of the shell, and as the liquid level of the outer periphery of the straightening cylinder rises, the to-be-filtered liquid also flows into the interior of the straightening cylinder from the axial upper side of the outer periphery of the straightening cylinder, thereby the membrane filaments in the region close to the axial end of the straightening cylinder in height are simultaneously subjected to the flow impact of the liquid flowing into the interior of the straightening cylinder through the flow-through hole close to the axial end of the straightening cylinder and the flow impact formed by the liquid flowing into the interior of the straightening cylinder from the open end of the straightening cylinder, both of which have a radial inward component, and the radial inward components of both are superimposed to act on the membrane filaments of the outer ring, causing the membrane filaments of the outer ring to form a relatively large amplitude radial swing or stretch, and since the region where the membrane filaments form the radial swing or stretch is relatively close to the potting part, damage is easily caused to the junction of the membrane filaments of the outer ring and the potting part.

[0007] On the outlet side, since the overall opening rate of the straightening cylinder is relatively high and the distance between the straightening cylinder and the outlet is relatively close, part of the to-be-filtered liquid in the straightening cylinder directly flows out of the straightening cylinder through the flow-through hole without being filtered by the membrane filaments, and then is discharged through the outlet, causing part of the liquid that has not been filtered by the hollow fiber membrane to be discharged through the outlet, so that more concentrated water needs to be returned to the module through the inlet again for filtration, thereby causing the overall filtration efficiency to decrease.

[0008] Therefore, it is necessary to further improve the hollow fiber membrane module to solve the above technical problems. Content of the utility model

[0009] In view of the deficiencies in the prior art, the utility model aims at providing a hollow fiber module, which solves the problem of damage or low filtration efficiency of the membrane filaments of the existing hollow fiber membrane module at the liquid inlet.

[0010] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0011] A hollow fiber module comprises:

[0012] A hollow fiber membrane bundle comprises a plurality of hollow fiber membrane filaments and two potting parts for constraining the axially opposite first end and second end of the hollow fiber membrane filaments, and at least one of the first end and the second end of the plurality of hollow fiber membrane filaments is open;

[0013] A container comprises a containing cavity, a first liquid passage, a second liquid passage and a filtered liquid outlet, the hollow fiber membrane bundle is axially fixed in the containing cavity, and the two potting parts are sealingly fixed with the inner wall of the container;

[0014] The area corresponding to the two sealing parts in the accommodating cavity is a raw liquid cavity, the first liquid inlet and the second liquid inlet are located at the axial ends of the raw liquid cavity and correspond to the first ends and the second ends of the plurality of hollow fiber membrane filaments respectively, and both of them communicate with the raw liquid cavity;

[0015] The filtrate outlet is located at the axial end of the accommodating cavity, and the area corresponding to the filtrate outlet and the corresponding sealing part in the accommodating cavity is a filtrate cavity;

[0016] It also comprises at least a first inner core surrounding the first ends of the plurality of hollow fiber membrane filaments, the first inner core is fixed relative to the container and has a first flow-through section corresponding to the first liquid inlet, and the first flow-through section is provided with a plurality of flow-through holes;

[0017] The first flow-through section of the first inner core forms a first solid section without holes away from one end of the corresponding sealing part, and the minimum distance between the first flow-through section and the second ends of the plurality of hollow fiber membrane filaments is L1, the minimum distance between the first liquid inlet and the second ends of the plurality of hollow fiber membrane filaments is L2, and the following condition is met, L1>L2.

[0018] In the hollow fiber module in the above technical solution, the first liquid inlet and the second liquid inlet both communicate with the raw liquid cavity, that is, correspond to the area of the hollow fiber membrane filaments between the two sealing parts, the hollow fiber membrane filaments are subjected to a radial force, the first inner core restrains and protects the area of the hollow fiber membrane filaments close to the first liquid inlet, and at the same time, the flow-through holes in the first flow-through section make the inside of the first inner core communicate with the first liquid inlet; the first solid section of the first inner core is the area between the boundary of the first flow-through section close to the second ends of the hollow fiber membrane filaments and the boundary of the first inner core close to the second ends of the hollow fiber membrane filaments, when the minimum distance between the first flow-through section and the second ends of the plurality of hollow fiber membrane filaments is greater than the minimum distance between the first liquid inlet and the second ends of the plurality of hollow fiber membrane filaments, it means that the axial length of the first solid section of the first inner core is relatively long, that is, the axial length of the first solid section is increased. Moreover, the length of the area of the first inner core exposed outside the sealing part is generally relatively fixed, and a part of the first solid section axially corresponds to the first liquid inlet, which also reduces the axial length of the first flow-through section to some extent.

[0019] When the first liquid passage is used as the liquid inlet, the hollow fiber module is installed with the first liquid passage located at the lower part of the module, the raw liquid enters the raw liquid cavity through the first liquid passage, part of the raw liquid directly enters the first inner core through the flow-through holes on the first flow-through section, and the remaining part of the raw liquid is contained in the raw liquid cavity outside the first inner core. As the liquid level outside the first inner core rises to the axial end of the first inner core, part of the raw liquid outside the first inner core will enter the first inner core through the open end of the first inner core. Due to the increase of the axial length of the first solid section, on the one hand, the flow rate of the part of the raw liquid entering the first inner core through the open end of the first inner core has been greatly reduced, which is much smaller than the flow rate when entering through the first liquid passage. The impact strength generated by this flow on the region of the membrane fibers of the outer ring corresponding to the axial end of the first inner core is greatly reduced. On the other hand, since no flow-through holes are provided on the first solid section, the membrane fibers of the outer ring corresponding to the axial end of the first inner core are only subjected to the flow impact of the above-mentioned flow with greatly reduced flow rate. Therefore, compared with the prior art, the impact strength of the flow on the region of the membrane fibers of the outer ring corresponding to the axial end of the first inner core is greatly reduced. On this basis, the increase of the axial length of the first solid section further increases the axial distance between the region subjected to the flow impact and the potting part, further reduces the amplitude of the radial swing or stretching of the membrane fibers of the outer ring relative to the potting part, and avoids damaging the junction of the membrane fibers of the outer ring and the potting part.

[0020] When the first liquid passage is used as the liquid outlet, the hollow fiber module is installed with the first liquid passage located at the upper part of the module, the raw liquid is in full contact with the hollow fiber membrane fibers, the filtrate enters the filtrate cavity through the hollow fiber membrane fibers, the remaining concentrated liquid inside the first inner core enters the first liquid passage through the flow-through holes on the first inner core, and the remaining concentrated liquid outside the first inner core also flows into the first liquid passage. Due to the increase of the axial length of the first solid section and the decrease of the axial length of the first flow-through section, the overall porosity of the first inner core is reduced, the amount of raw liquid inside the first inner core directly flowing to the first liquid passage without filtration by the membrane fibers is greatly reduced, and the amount of secondary reflux concentrated liquid is reduced. Moreover, since the first solid section is located at the axial end of the second end of the first inner core close to the hollow fiber membrane fibers and below the first flow-through section in the axial direction, the raw liquid inside the first solid section must continue to flow axially upward to reach the corresponding region of the first flow-through section and then be discharged through the flow-through holes. The extension of the axial length of the first solid section is equivalent to the extension of the residence time of the raw liquid in the hollow fiber module, the increase of the contact filtration time of the raw liquid with the hollow fiber membrane fibers, and the reduction of the amount of secondary reflux concentrated liquid, thereby improving the filtration efficiency of the liquid.

[0021] In summary, regardless of whether the first liquid passage is used as the liquid inlet or the liquid outlet, the longer first solid section on the first inner core can bring beneficial effects: avoiding damage to the junction of the membrane fibers of the outer ring and the potting part, or improving the overall filtration efficiency.

[0022] Preferably, the axial length of the first solid section is 30%-35% of the total axial length of the first inner core.

[0023] When the first liquid inlet is the liquid inlet, the first solid section within the above ratio range makes the axial distance between the open end of the first inner core and the liquid inlet large enough, and the flow rate of the raw liquid rising to the end of the first inner core decreases significantly, so that the impact of the fluid flowing into the inside of the first inner core through the end of the first solid section on the corresponding area of the hollow fiber membrane wire of the outer ring is small, and the hollow fiber membrane wire of the outer ring does not produce a large radial swing or stretching amplitude, thereby greatly reducing the damage to the junction of the membrane wire of the outer ring and the first potting part, and better protecting the membrane wire of the outer ring. Moreover, the first solid section cannot be too long, because it will cause the first flow-through section to be too short, thereby causing the opening rate of the first inner core to be too low to ensure that the area of the hollow fiber membrane wire inside the first inner core is fully utilized.

[0024] When the first liquid inlet is the liquid outlet, the axial length of the first solid section within the above ratio range is long enough, and the overall opening rate of the first inner core is moderate, which appropriately prolongs the residence time and contact filtering time of the raw liquid inside the first inner core, reduces the proportion of unfiltered liquid in the concentrated liquid, reduces the amount of concentrated liquid that needs to be returned, and improves the filtering efficiency.

[0025] Preferably, the axial length of the first flow-through section is 40%-50% of the total axial length of the first inner core.

[0026] The proportion of the first flow-through section represents the flow-through capacity of the first inner core. Controlling the ratio within the above range can not only ensure the flow-through capacity of the first inner core and the filtering rate of the overall module, but also reserve enough area for the first solid section to achieve the beneficial effects described above.

[0027] Preferably, the axial length L3 of the directly opposite area of the first solid section and the first liquid inlet is L1-L2, the axial length of the first solid section is L4, and the following conditions are met: L3≤30% L4; and / or, L4-L3=15-40mm.

[0028] The second end of the hollow fiber membrane wire is away from the first flow-through section relative to the first liquid inlet, and the side of the first liquid inlet close to the second end of the hollow fiber membrane wire is opposite to part of the area of the first solid section, that is, the first solid section has an area directly opposite to the side of the first liquid inlet close to the second end of the hollow fiber membrane wire, which is defined as the directly opposite area. The directly opposite area significantly increases the axial length of the first solid section, which can avoid damaging the junction of the membrane wire of the outer ring and the potting part or improve the overall filtering efficiency, as described above.

[0029] The area of the first entity section other than the area opposite to the region is an area offset from the first liquid passage, and the axial length thereof is L4-L3, which represents the axial length of the raw liquid that has not entered the first inner core through the first flow passage and still needs to continue to flow after entering from the liquid inlet, or represents the axial length of the gap between the area where the second entity section is offset from the first liquid passage and the inner wall of the container, and the axial length thereof is ensured to be 15-40 mm, so that the flow rate of the raw liquid reaching the end of the first entity section is correspondingly reduced to a reasonable range, or the residence time of the raw liquid inside the first inner core is reasonably prolonged, thereby effectively reducing the impact of the raw liquid on the area of the outer membrane filament corresponding to the end of the first entity section or reducing the proportion of the liquid to be filtered in the concentrated liquid, while keeping the filtration rate within a reasonable range and not excessively reducing the overall filtration efficiency.

[0030] Preferably, the radial gap width between the axial end of the first entity section and the inner wall of the container is d1, the minimum distance between the first liquid passage and the second end of the plurality of hollow fiber membrane filaments is located at a reference point, and the radial gap width between the first entity section and the reference point is d2, satisfying the following conditions: 0

[0031] When the first liquid passage is the liquid inlet, the above range of ratios causes the corresponding flow channel to narrow and the flow area to decrease during the upward flow of the raw liquid that has not entered the first inner core through the first flow passage, which increases the flow resistance of the liquid flowing from the gap around the first entity section to the cavity above the first inner core to an appropriate extent, thereby causing more raw liquid to enter the first inner core through the first flow passage, improving the utilization rate of the hollow fiber membrane filaments inside the first inner core, and an appropriate amount of raw liquid flows axially upward through the flow channel around the first entity section to the cavity above the first inner core, filtered by the area above the first inner core where the hollow fiber membrane filaments are located, which is equivalent to appropriately distributing the raw liquid, fully utilizing each part of the hollow fiber membrane filaments, and accelerating the filtration rate. Moreover, due to the decrease in the flow rate of the raw liquid flowing upward outside the first inner core, the impact intensity of the raw liquid on the area of the outer hollow fiber membrane filament corresponding to the end of the first inner core is also reduced.

[0032] When the first liquid passage is the liquid outlet, the concentrated liquid below the first inner core flows upward from the gap between the end of the first solid section and the inner wall of the container, and then flows to the liquid outlet and is discharged. In the above range of the ratio, the width d1 of the end of the first solid section away from the liquid outlet is smaller, and the corresponding flow passage area is smaller, which increases the flow resistance to a certain extent, promotes more raw liquid to flow into the interior of the first inner core, continues to be filtered by the membrane filaments located in the interior of the first inner core, reduces the concentrated liquid flowing to the liquid outlet directly through the gap around the periphery of the first solid section, to a certain extent, reduces the amount of concentrated liquid that needs to be reflowed, and improves the filtration efficiency. On the other hand, the minimum distance between the first liquid passage and the second end of the plurality of hollow fiber membrane filaments is at the reference point, and the radial distance d2 between the first solid section is larger, so that the raw liquid reaching the vicinity of the reference point can be quickly discharged, and the ratio of d1 / d2 is controlled in the above range, which ensures that enough raw liquid flows into the interior of the first inner core, ensures that the area where the hollow fiber membrane filaments are located in the interior of the first inner core is fully utilized, and also ensures that the discharge rate of the concentrated liquid around the periphery of the first inner core is high enough to ensure a high filtration rate.

[0033] Preferably, the flow passage cross-sectional area of the first liquid passage is S1, the area of the radial gap between the first solid section, the first flow passage section and the inner wall of the container is S2, and the following conditions are met: S2 / S1=0.8-2.2.

[0034] S2 / S1 is in the range of 0.8-2.2, which has the effect that the flow passage area changes little when the liquid flows into or out of the raw liquid cavity, and there is no large flow rate fluctuation, the liquid flow state is relatively stable, and the stress and strain on the hollow fiber membrane filaments, the first inner core and the container are also smaller, which better protects the membrane filaments and the first inner core in the outer circle.

[0035] Preferably, the first inner core has a bonding section at one end of the first flow passage section away from the first solid section, the bonding section is inserted into the potting portion, the axial length of the bonding section is L5, and the axial length of the potting portion is L6, and the following conditions are met: L5 / L6=0.3-0.7.

[0036] The first inner core is partially inserted into the potting portion, and the first end of the hollow fiber membrane filaments and the first inner core are fixedly connected and fixedly connected with the container; the bonding section represents the area where the first inner core is inserted into the potting portion, and the ratio of the axial length of the bonding section to the potting portion is in the above range, so that the potting portion has a portion that is not inserted by the first inner core. The potting portion is not divided into inner and outer areas by the first inner core, but is bonded as a whole around the hollow fiber membrane filaments, has a larger mechanical strength, and has a larger bonding strength with the inner wall of the container, which is conducive to improving the connection stability of the first inner core, the potting portion and the inner wall.

[0037] Preferably, the outer periphery of the axial end of the first entity section is axially fixed to the container by a plurality of clamping lugs arranged at a circumferential interval; the clamping lugs serve to fix the first inner core in the container, axially limit the first inner core and the hollow fiber membrane bundle, and prevent the first inner core and the hollow fiber membrane bundle from shaking relative to the container, thereby protecting the hollow fiber membrane filaments and the potting portion.

[0038] Preferably, the potting portion has an annular non-porous region at the end away from the first flow-through section; the non-porous region serves to improve the mechanical strength of the first inner core, radially constrain and tightly grip the potting portion and the hollow fiber membrane filaments therein, and increase the bonding area and bonding strength of the first inner core and the potting portion.

[0039] In some embodiments, the axial length of the non-porous region is not less than 10% L5, the potting portion has a larger bonding area and bonding strength with the non-porous region, and the possibility of the potting portion shaking relative to the first inner core is reduced; and more areas of the hollow fiber membrane filaments are left uncovered by the potting portion, thereby improving the filtration efficiency.

[0040] In some embodiments, the bonding section further comprises an open region between the non-porous region and the first flow-through section, the potting portion is bonded to both the open region and the non-porous region, and part of the potting portion is embedded in the through holes of the open region to form a bridge-like connection; the combination of the two ensures a higher bonding strength of the potting portion and the first inner core under the premise of ensuring the bonding area.

[0041] Preferably, the hollow fiber module further comprises a second inner core surrounding the second ends of the plurality of hollow fiber membrane filaments, the second inner core is fixed relative to the container, the second inner core has a second flow-through section and a second entity section, the second flow-through section corresponds to the second liquid inlet, and the minimum distance between the second flow-through section of the second inner core and the first ends of the plurality of hollow fiber membrane filaments is H1, the minimum distance between the second liquid inlet and the first ends of the plurality of hollow fiber membrane filaments is H2, and H1>H2 is satisfied.

[0042] The first inner core and the second inner core correspond to the liquid inlet and the liquid outlet, respectively, and both have longer entity sections, so that the hollow fiber module of the present application can have both effects, i.e., avoiding damage to the junction between the outermost membrane filaments and the potting portion and improving the overall filtration efficiency.

[0043] In summary, compared with the prior art, the present application has at least the following beneficial effects:

[0044] The hollow fiber module in the technical solution has the first liquid passage and the second liquid passage both communicating with the raw liquid cavity, i.e. corresponding to the region between the two potting portions of the hollow fiber membrane bundle, the hollow fiber membrane filaments are subjected to a radial force, the first inner core restrains and protects the region of the hollow fiber membrane filaments close to the first liquid passage, and the first inner core is communicated with the first liquid passage through the flow holes in the first flow passage; the first solid section of the first inner core is the region between the boundary of the first flow passage close to the second end of the hollow fiber membrane filament and the boundary of the first inner core close to the second end of the hollow fiber membrane filament, when the minimum distance from the first flow passage to the second end of the hollow fiber membrane filament is greater than the minimum distance from the first liquid passage to the second end of the hollow fiber membrane filaments, the axial length of the first solid section of the first inner core is relatively long, i.e. the axial length of the first solid section is increased, and moreover, the first solid section has a part axially corresponding to the first liquid passage, which also reduces the axial length of the first flow passage to a certain extent.

[0045] When the first liquid passage is used as the liquid inlet, the first liquid passage is located at the lower part of the module during installation of the hollow fiber module, the raw liquid enters the raw liquid cavity through the first liquid passage, part of the raw liquid directly enters the first inner core through the flow holes on the first flow passage, and the remaining part of the raw liquid is contained in the raw liquid cavity outside the first inner core. As the liquid level outside the first inner core rises to the axial end of the first inner core, part of the raw liquid outside the first inner core enters the first inner core through the open end of the first inner core. Since the axial length of the first solid section is increased, on the one hand, the flow rate of the part of the raw liquid entering the first inner core through the open end of the first inner core is greatly reduced, which is much smaller than the flow rate when entering through the first liquid passage, and the impact strength generated by this flow on the region of the outer membrane filaments corresponding to the axial end of the first inner core is greatly reduced; on the other hand, no flow holes are arranged on the first solid section, so that the region of the outer membrane filaments corresponding to the axial end of the first inner core is only subjected to the flow impact with the above-mentioned greatly reduced flow rate, and therefore, compared with the prior art, the impact strength of the flow impact on the region of the outer membrane filaments of the hollow fiber membrane bundle corresponding to the axial end of the first inner core is greatly reduced; on this basis, the increase of the axial length of the first solid section further increases the axial distance between the region of the hollow fiber membrane filaments subjected to the flow impact and the potting portion, and further reduces the amplitude of the radial swing or stretching of the outer hollow fiber membrane filaments relative to the potting portion, thereby avoiding damage to the junction of the outer hollow fiber membrane filaments and the potting portion.

[0046] When the first liquid passage is used as the liquid outlet, the hollow fiber module is installed, the first liquid passage is located at the upper part of the module, the raw liquid is in full contact with the hollow fiber membrane, the filtrate enters the filtrate cavity through the hollow fiber membrane, the residual concentrated liquid in the first inner core enters the first liquid passage from the flow-through hole on the first inner core, the residual concentrated liquid outside the first inner core also flows into the first liquid passage, the axial length of the first solid section is increased, the axial length of the first flow-through section is reduced, the opening rate of the first inner core as a whole is reduced, the amount of the raw liquid in the first inner core which directly flows to the first liquid passage without being filtered by the membrane is greatly reduced, and the amount of the concentrated liquid which needs to be returned for the second time is reduced; and since the first solid section is located at the axial end of the first inner core close to the second end of the hollow fiber membrane and is located below the axial direction of the first flow-through section, the raw liquid in the first solid section needs to continue to flow axially upward to reach the corresponding area of the first flow-through section and then be discharged through the flow-through hole, the axial length of the first solid section is prolonged, which is equivalent to prolonging the residence time of the raw liquid in the hollow fiber module, increasing the contact and filtration time of the raw liquid with the hollow fiber membrane, reducing the amount of the concentrated liquid which needs to be returned for the second time, and improving the filtration efficiency of the liquid.

[0047] In general, no matter whether the first liquid passage is used as the liquid inlet or the liquid outlet, the longer first solid section on the first inner core can bring beneficial effects: avoiding damaging the junction between the membrane at the outer circle and the potting part, or improving the overall filtration efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0049] Figure 1 The drawings are the drawings of the hollow fiber membrane assembly of the prior art.

[0050] Figure 2 The drawings are the cross-sectional schematic view of the hollow fiber module of the embodiments of the present application.

[0051] Figure 3 The drawings are the cross-sectional schematic view of the hollow fiber module of the embodiments of the present application. Figure 2 The drawings are the cross-sectional schematic view of the hollow fiber module of the embodiments of the present application.

[0052] Figure 4 The drawings are the cross-sectional schematic view of the hollow fiber module of the embodiments of the present application. Figure 2 The drawings are the cross-sectional schematic view of the hollow fiber module of the embodiments of the present application.

[0053] Figure 5 The drawings are the cross-sectional schematic view of the hollow fiber module of the embodiments of the present application.

[0054] Figure 6 It is a cross section schematic view of the first inner core of the utility model embodiment.

[0055] Explanation of reference signs

[0056] 10, hollow fiber membrane bundle;11, membrane filament;111, first end;112, second end;12, potting part;

[0057] 20, container;21, containing cavity;211, stock solution cavity;222, filtrate cavity;22, first liquid passage;23, second liquid passage;24, filtrate outlet;25, barrel;26, end cover;

[0058] 30, first inner core;31, first solid section;311, directly opposite area;32, first flow-through section;321, flow-through hole;33, bonding section;331, non-hole area;332, open hole area;34, clamping lug;

[0059] 40, second inner core;41, second solid section;42, second flow-through section. DETAILED DESCRIPTION

[0060] The technical solutions of the utility model will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without making creative efforts fall within the protection scope of the utility model.

[0061] In the description of the utility model, it needs to be explained that the orientation or position relation indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is the orientation or position relation shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and cannot be understood as a limitation on the utility model that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0062] In the description of the utility model, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected;It can be mechanical connection, or electrical connection;It can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0063] As shown in the drawings,Figure 2 As shown, the hollow fiber module of the embodiment of the utility model, including hollow fiber membrane bundle 10, container 20 and first inner core 30, hollow fiber membrane bundle 10 is fixed axially in container 20, specifically, hollow fiber membrane bundle 10 includes multiple hollow fiber membrane filaments 11 and two potting portions 12 of the first end 111 and the second end 112 of the axially opposite constraint hollow fiber membrane filament 11, the first end 111 and the second end 112 of the multiple hollow fiber membrane filaments 11 in the potting portion 12 at least one is open, for the filtrate in the hollow fiber membrane filament 11 flows out, container 20 includes containing cavity 21, first liquid passage 22, second liquid passage 23 and filtrate outlet 24, and two potting portions 12 are sealed and fixed with the inner wall of container 20, the area between two potting portions 12 is raw liquid cavity 211 for containing cavity 21, first liquid passage 22 and second liquid passage 23 are located at the axial ends of raw liquid cavity 211 and correspond to the first end 111 and the second end 112 of multiple hollow fiber membrane filaments 11 respectively, and both are communicated with raw liquid cavity 211, and filtrate outlet 24 is located at the axial end of containing cavity 21, and the area between filtrate outlet 24 and the corresponding potting portion 12 for containing cavity 21 is filtrate cavity 222, first liquid passage 22 can be liquid inlet, and correspondingly, second liquid passage 23 is liquid outlet, or, first liquid passage 22 is liquid outlet, and correspondingly, second liquid passage 23 is liquid inlet.

[0064] In order to avoid the gas block in container 20, the hollow fiber module of the embodiment of the utility model is used, the liquid inlet is located in the lower part of the module, the liquid outlet is located in the upper part of the module, and the liquid inlet and the liquid outlet are both arranged on the side of container 20 and correspond to the area between two potting portions 12 of hollow fiber membrane filaments 11, and hollow fiber membrane filaments 11 are subjected to radial force, as shown in the attached Figure 2 As shown, the direction is taken as an example, first liquid passage 22 is liquid inlet, and second liquid passage 23 is liquid outlet, raw liquid enters first liquid passage 22 and contacts and filters hollow fiber membrane filaments 11, the liquid level in raw liquid cavity 211 gradually rises, and the gas in containing cavity 21 and hollow fiber membrane filaments 11 is discharged through filtrate outlet 24 or liquid outlet, to avoid the occurrence of gas block, and then the filtrate is formed in hollow fiber membrane filaments 11 and flows to filtrate outlet 24 through the open port thereof, the liquid remaining outside hollow fiber membrane filaments 11 and the unfiltered raw liquid are discharged through the upper liquid outlet, and since the unfiltered raw liquid is contained, the part of liquid will be backflowed again, enters raw liquid cavity 211 again through liquid inlet, and is filtered again.

[0065] In order to protect the hollow fiber membrane filaments 11, the module further comprises a first inner core 30 surrounding at least the first ends 111 of the plurality of hollow fiber membrane filaments 11, the first inner core 30 being fixed relative to the container 20 and having a first flow-through section 32 corresponding to the first liquid passage 22, the first flow-through section 32 being provided with a plurality of flow-through holes 321, the first flow-through section 32 of the first inner core 30 being formed into a first solid section 31 without holes away from one end of the corresponding potting portion 12, and the minimum distance between the first flow-through section 32 and the second ends 112 of the plurality of hollow fiber membrane filaments 11 being L1, the minimum distance between the first liquid passage 22 and the second ends 112 of the plurality of hollow fiber membrane filaments 11 being L2, satisfying the following condition: L1>L2.

[0066] As shown in the accompanying drawings, Figure 2 and the accompanying drawings, Figure 5 The first solid section 31 of the first inner core 30 is the area between the boundary of the first flow-through section 32 close to the second ends 112 of the hollow fiber membrane filaments 11 and the boundary of the first inner core 30 close to the second ends 112 of the hollow fiber membrane filaments 11. When the minimum distance between the first flow-through section 32 and the second ends 112 of the hollow fiber membrane filaments 11 is greater than the minimum distance between the first liquid passage 22 and the second ends 112 of the plurality of hollow fiber membrane filaments 11, the axial length of the first solid section 31 of the first inner core 30 is relatively long, i.e., the axial length of the first solid section 31 is increased.

[0067] It should be noted that, whether it is the utility model or the prior art, the container 20 comprises a barrel 25 and two end covers 26, the two end covers 26 being bonded to the two ends of the barrel 25 by adhesive, the first liquid passage 22 and the second liquid passage 23 being arranged on the side walls of the respective end covers 26, the filtrate outlet 24 being located at the axial end of the end cover 26, and the axial end of the first inner core 30 being fixed and flush with the junction of the barrel 25 and the end cover 26, i.e., the axial length of the first solid section 31 is related to the size of the end cover 26, and in the case where the sizes of the end covers 26 of the container 20 are the same, the axial length of the first solid section 31 of the embodiment is obviously greater than the axial length of the solid section at the axial end of the rectifier cylinder in the prior art, thereby achieving different effects.

[0068] Specifically, the hollow fiber module is as shown in the accompanying drawings, Figure 2In the installation method described above, the first liquid inlet 22 is located at the bottom of the module. When used as a liquid inlet, the raw liquid enters the raw liquid chamber 211 through the first liquid inlet 22. Part of the raw liquid directly enters the first inner core 30 through the flow hole 321 on the first flow section 32, while the remaining raw liquid is contained within the raw liquid chamber 211 and outside the first inner core 30. As the liquid level outside the first inner core 30 rises to the axial end of the first inner core 30, some of the raw liquid outside the first inner core 30 will enter the first inner core 30 through the end opening. Due to the increased axial length of the first solid section 31, on the one hand, the flow rate of the raw liquid entering the first inner core 30 through the end opening has been greatly reduced, much less than the flow rate when entering through the first liquid inlet 22; on the other hand... On the one hand, no flow holes 321 are provided on the first solid segment 31, so the region of the outer ring membrane filament 11 corresponding to the axial end of the first inner core 30 is only subjected to the flow impact of the significantly reduced flow velocity mentioned above. Therefore, compared with the prior art, the intensity of the flow impact on the region of the outer ring membrane filament 11 corresponding to the axial end of the first inner core 30 is significantly reduced. On this basis, the increase in the axial length of the first solid segment 31 increases the axial distance between the region of the hollow fiber membrane filament 11 subjected to the flow impact and the potting part 12, further reducing the amplitude of the radial swing or stretch of the outer ring hollow fiber membrane filament 11 relative to the potting part 12, and avoiding damage to the junction of the outer ring hollow fiber membrane filament 11 and the potting part 12.

[0069] If the installation direction of the hollow fiber module is... Figure 2 The module is rotated 180°, with the first liquid outlet 22 located at the top. When used as an outlet, the raw liquid comes into full contact with the hollow fiber membrane 11, and the filtrate enters the filtrate chamber 222 through the hollow fiber membrane 11. The remaining concentrated liquid inside the first inner core 30 enters the first liquid outlet 22 through the flow hole 321 on the first inner core 30, and the remaining concentrated liquid outside the first inner core 30 also flows into the first liquid outlet 22. Due to the increase in the axial length of the first solid section 31 and the decrease in the axial length of the first flow section 32, the overall porosity of the first inner core 30 decreases, and the amount of raw liquid flowing directly from the first inner core 30 to the first liquid outlet 22 without being filtered by the membrane 11 is greatly reduced. The amount of concentrate requiring secondary reflux is reduced. Moreover, since the first solid section 31 is located at the axial end of the second end of the first inner core 30 near the hollow fiber membrane filament 11 and below the first flow section 32, the raw liquid inside the first solid section 31 must continue to flow upward axially to reach the area corresponding to the first flow section 32 before entering the first liquid inlet 22 and then being discharged through the flow hole 321. This extends the axial length of the first solid section 31, which is equivalent to extending the residence time of the raw liquid in the hollow fiber module, increasing the contact filtration time between the raw liquid and the hollow fiber membrane filament 11, reducing the amount of concentrate requiring secondary reflux, and improving the filtration efficiency of the liquid.

[0070] In summary, whether the first liquid inlet 22 corresponds to the liquid inlet or the liquid outlet, the longer first solid section 31 on the first inner core 30 can bring beneficial effects: avoiding damage to the junction of the outer membrane filaments 11 and the filling section 12, or improving the overall filtration efficiency.

[0071] It should be noted that the first inner core 30 may be provided only at the first end 111 or the second end 112 of the multiple hollow fiber membrane filaments 11, that is, the first inner core 30 may be provided only at the corresponding liquid inlet or liquid outlet end.

[0072] If you want to achieve both effects, the preferred option is as follows: Figure 2 As shown, this embodiment also includes a second inner core 40 surrounding the second end 112 of multiple hollow fiber membrane filaments 11. The second inner core 40 is fixed relative to the container 20. The second inner core 40 has a second flow section 42 and a second solid section 41. The second flow section 42 corresponds to the second liquid inlet 23. The minimum distance between the second flow section 42 of the second inner core 40 and the first end 111 of the multiple hollow fiber membrane filaments 11 is H1, and the minimum distance between the second liquid inlet 23 and the first end 111 of the multiple hollow fiber membrane filaments 11 is H2, satisfying the following condition: H1>H2.

[0073] To reduce processing difficulty and cost, and simplify usage steps, the structure of the first inner core 30 can be exactly the same as that of the second inner core 40, and the structures of the first liquid inlet 22 and the second liquid inlet 23 can also be exactly the same. The first end 111 and the second end 112 of the hollow fiber membrane filtrate 11 are both open. Both axial ends of the container 20 are provided with filtrate outlets 24, which correspond to the first end 111 and the second end 112 of the hollow fiber membrane filtrate 11, respectively. Accordingly, the receiving cavity 21 includes two filtrate cavities 222, so that filtrate can be discharged from both axial ends.

[0074] For the sake of simplicity, the embodiments of this utility model are illustrated in the appendix. Figures 2 to 5 Taking a specific example, the hollow fiber module of this embodiment will be described.

[0075] Figure 2In the specific numerical or ratio range, the first solid section 31 can be different from the second solid section 41, and the first flow-through section 32 can be different from the second flow-through section 42. Similarly, the first inner core 30 and the second inner core 40 can both have the adhesive section 33, and the adhesive section 33 has the non-porous area 331 and / or the open-pore area 332. The first inner core 30 and the second inner core 40 can both have a plurality of clamping lugs 34 to form axial fixation with the container 20.

[0076] It should be noted that the axial end of the first inner core 30 is the end close to the second end 112 of the hollow fiber membrane filament 11, and the starting end is the end close to the first end 111 of the hollow fiber membrane filament 11. The axial end of the second inner core 40 is the end close to the first end 111 of the hollow fiber membrane filament 11, and the starting end is the end close to the second end 112 of the hollow fiber membrane filament 11. Moreover, the first flow-through section 32 of the first inner core 30 is circumferentially staggered with the first liquid passage 22, i.e., the region of the first flow-through section 32 directly opposite the first liquid passage 22 is non-porous. The second flow-through section 42 of the second inner core 40 is circumferentially staggered with the second liquid passage 23, i.e., the region of the second flow-through section 42 directly opposite the second liquid passage 23 is non-porous.

[0077] Specifically, the axial length of the first solid section 31 is 30%-35% of the total axial length of the first inner core 30, and the axial length of the second solid section 41 is 30%-35% of the total axial length of the second inner core 40.

[0078] For the first liquid passage 22 as the liquid inlet, the first solid section 31 in the above ratio range makes the axial spacing between the open end of the axial end of the first inner core 30 and the liquid inlet large enough. Whether it is the original liquid rising to the end of the first inner core 30 through the flow-through hole 321 or the original liquid rising to the end of the first inner core 30 outside the first inner core 30, the flow rate has been significantly reduced, and the impact on the hollow fiber membrane filament 11 is smaller. The peripheral hollow fiber membrane filament 11 will not produce a large radial swing or stretching amplitude, thereby greatly reducing the damage to the junction of the outer ring of the membrane filament 11 and the first potting portion 12, and better protecting the outer ring of the membrane filament 11.

[0079] If the ratio of the axial length of the first solid section 31 to the total axial length of the first inner core 30 is less than 30%, the axial length of the first solid section 31 is insufficient, the flow rate of the raw liquid in and out of the first inner core 30 is not significantly slowed down, and the hollow fiber membrane filaments 11 are still subjected to a relatively large impact. If the ratio of the axial length of the first solid section 31 to the total axial length of the first inner core 30 is greater than 35%, the axial length of the first solid section 31 is too long, the axial length of the region corresponding to the hollow fiber membrane filaments 11 wrapped is too long, the flow channel above the liquid inlet and the outer periphery of the membrane bundle is hindered too much, thereby negatively affecting the filtration rate, resulting in a decrease in the overall filtration efficiency; at the same time, the axial length of the first flow-through section 32 of the first inner core 30 is insufficient, the opening rate of the first inner core 30 is too low, the raw liquid is hindered when entering the first inner core 30, and the region inside the first inner core 30 where the hollow fiber membrane filaments 32 are located cannot be fully utilized.

[0080] For the second liquid outlet 23 as the liquid outlet, the axial length of the second solid section 41 in the above ratio range is sufficient, and the overall opening rate of the second inner core 40 is moderate, appropriately prolonging the residence time of the raw liquid inside the second inner core 40 and the contact filtration time with the membrane filaments 11, reducing the proportion of unfiltered liquid in the concentrated liquid, reducing the amount of concentrated liquid that needs to be returned, and improving the filtration efficiency.

[0081] If the ratio of the axial length of the second solid section 41 to the total axial length of the second inner core 40 is less than 30%, the residence time of the raw liquid inside the second inner core 40 and the contact filtration time with the membrane filaments 11 are insufficient, and the effect of improving the filtration efficiency is not obvious. If the ratio of the axial length of the second solid section 41 to the total axial length of the second inner core 40 is greater than 35%, the proportion of the second flow-through section 42 in the second inner core 40 becomes smaller, thereby causing the opening rate of the second inner core 40 to be too low, the discharge efficiency of the concentrated liquid inside the second inner core 40 to decrease, resulting in a decrease in the overall filtration efficiency, and also causing the flow resistance inside the second inner core 40 to be too large, the raw liquid not to easily enter the second inner core 40 and the region inside the second inner core 40 where the hollow fiber membrane filaments 32 are located to continue to contact, the region inside the second inner core 40 where the hollow fiber membrane filaments 32 are located to be unable to be fully utilized, the amount of concentrated liquid that needs to be returned to increase, and the amount of concentrated liquid that needs to be returned to increase.

[0082] The proportion of the first flow-through section 32 represents the flow-through capacity of the first inner core 30, and the axial length of the first flow-through section 32 is 40%-50% of the total axial length of the first inner core 30; the proportion of the second flow-through section 42 represents the flow-through capacity of the second inner core 40, and the axial length of the second flow-through section 42 is 40%-50% of the total axial length of the second inner core 40; controlling the ratio in the above range can not only ensure the flow-through capacity of the first inner core 30 and the second inner core 40 and the filtration efficiency of the overall module, but also reserve sufficient regions for the first solid section 31 and the second solid section 41 to achieve the beneficial effects described above.

[0083] If the ratio of the first flow-through section 32 to the second flow-through section 42 is less than 40%, the flow capacity of the first inner core 30 and the second inner core 40 is poor, liquid is not easy to enter the first inner core 30, the area of the hollow fiber membrane filaments 32 inside the first inner core 30 cannot be fully utilized, at the same time, the concentrated liquid is not easy to flow out of the second inner core 40, which affects the flow rate of the liquid and the overall filtration efficiency, and the flow resistance inside the second inner core 40 is too large, the raw liquid is not easy to enter the second inner core 40 and continue to contact the area of the hollow fiber membrane filaments 32 inside the second inner core 40, and the area of the hollow fiber membrane filaments 32 inside the second inner core 40 cannot be fully utilized.

[0084] If the ratio of the first flow-through section 32 to the second flow-through section 42 is greater than 50%, the remaining area of the first inner core 30 and the second inner core 40 is too small, and the first inner core 30 and the second inner core 40 need to be bonded with the potting portion 12, that is, the bonding section 33 described below. In order to ensure the axial length of the first solid section 31 and the second solid section 41, the bonding length of the first inner core 30, the second inner core 40 and the corresponding potting portion 12 needs to be shortened, which affects the bonding firmness of the first inner core 30, the second inner core 40 and the corresponding potting portion 12. When the radial impact force of the liquid flowing in from the liquid inlet and flowing out from the liquid outlet, the first inner core 30, the second inner core 40 is easy to shake relatively, which causes the bonding position of the first inner core 30, the second inner core 40 and the corresponding potting portion 12 to be damaged or even separated; if the bonding length of the first inner core 30, the second inner core 40 and the corresponding potting portion 12 is ensured, the axial length of the first solid section 31 and the second solid section 41 is too short, and the above effective effect cannot be achieved.

[0085] As shown in the accompanying drawings, Figure 2 The radial projection of the first liquid passage 22 covers part of the area of the first flow-through section 32 and the first solid section 31, that is, the first solid section 31 has an area directly opposite the first liquid passage 22, and the radial projection of the second liquid passage 23 covers the second flow-through section 42 and part of the second solid section 41, that is, the second solid section 41 has an area directly opposite the second liquid passage 23, and both of these areas can be defined as the directly opposite area 311. As for the directly opposite area 311 of the first solid section 31, its axial length L3=L1-L2, and in the prior art, this part of the area is still part of the flow-through section, therefore, the setting of the directly opposite area 311 of the first solid section 31 of the present embodiment greatly increases the axial length of the first solid section 31. The length of the area of the first inner core 30 exposed outside the potting portion 12 is generally relatively fixed, and a part of the first solid section 31 is axially corresponding to the first liquid passage 22, which also reduces the axial length of the first flow-through section 32 to a certain extent.

[0086] The axial length of the first entity section 31 is L4, and the following condition is met: L3≤30% L4. The remaining part is the misaligned area with the first liquid inlet 22, and the proportion is at least greater than 70%. Based on this, due to the existence of the directly opposite area 311, the axial length of the first entity section 31 of the present embodiment is significantly greater than the axial length of the entity section in the prior art, and by limiting the axial length of the directly opposite area 311, the reasonable length of the first entity section 31 and the first flow-through section 32 is ensured, and the flow-through performance of the first inner core 30 and the protection of the hollow fiber membrane filaments 11 are taken into account.

[0087] If L3>30% L4, the proportion of the directly opposite area 311 is too large, and too much of the area of the first flow-through section 32 is occupied, so that many liquids entering from the first liquid inlet 22 cannot directly enter the first inner core 30 through the flow-through holes 321, and the area of the hollow fiber membrane filaments 11 in the first inner core 30 cannot be fully utilized, reducing the filtration efficiency and rate; and the axial length of the misaligned area is shortened, so that the liquid entering from the first liquid inlet 22 near the second end 112 of the hollow fiber membrane filament 11 quickly reaches the axial end of the first inner core 30, and the flow rate cannot be reduced to a suitable range, and the outer ring membrane filaments 11 near the axial end of the first inner core 30 still have a large impact force, which is not conducive to the protection of the hollow fiber membrane filaments 11 and the potting portion 12.

[0088] Similarly, the axial length of the directly opposite area 311 of the second entity section 41 is H3=H1-H2, and the axial length of the second entity section 41 is H4. The following condition is met: H3≤30% H4, so that the second entity section 41 does not excessively occupy the area of the second flow-through section 42, ensuring the flow-through capacity of the second inner core 40, and ensuring that the second entity section 41 has a long enough gap with the inner wall of the container 20, which has a moderate flow resistance, which can guide more liquid to flow into the second inner core 40 before flowing out of the second liquid inlet 23, and also avoids the flow resistance between the second inner core 40 and the inner wall of the container 20 being too large, so that the discharge rate of the concentrated liquid decreases, and the overall filtration rate decreases.

[0089] In the first inner core 30, the axial length of the misaligned area of the first entity section 31 and the first liquid inlet 22 is L4-L3, and L4-L3=15-40 mm, which represents the original liquid entering from the liquid inlet that does not directly enter the first inner core 30, which still needs to continue to flow upward between the first inner core 30 and the inner wall of the container 20. By controlling the axial length of the misaligned area within the above range, the speed of the original liquid on the outer periphery of the first inner core 30 can be slowed down to a suitable range, which effectively reduces the impact force of the original liquid on the outer ring membrane filaments 11, and does not excessively reduce the overall filtration efficiency.

[0090] If its axial length is less than 15mm, even if the axial length of the area 311 is added, the length of the first solid segment 31 is still insufficient. Although it still has a certain effect compared with the prior art, the effect is not significant enough. The liquid flowing in from the inlet still exerts a relatively strong impact force on the hollow fiber membrane filament 11 and the area corresponding to the end of the first solid segment 31.

[0091] If its axial length is greater than 40mm, the axial length of the first solid segment 31 and the misaligned area with the first liquid inlet 22 is too long. Correspondingly, the axial length of the area of ​​the hollow fiber membrane filament 11 covered by the first inner core is too long, resulting in excessive flow resistance to the raw liquid around the outer periphery of the first inner core 30, which in turn has a negative impact on the filtration rate, resulting in an overall filtration rate that is too low.

[0092] In the second inner core 40, the axial length of the misaligned area between the second solid section 41 and the second liquid inlet 23 is H4-H3, where H4-H3 = 15-40 mm. This represents the axial length of the gap between the misaligned area of ​​the second solid section 41 and the second liquid inlet 23 and the inner wall of the container 20. If the axial length of the misaligned area is less than 15 mm, the axial length of the second solid section 41 is too small. Although the residence time of the concentrate in the second inner core 40 and the contact filtration time with the membrane fiber 11 are longer than those in the prior art, they are still relatively short, and a large amount of unfiltered liquid remains in the discharged concentrate. If the axial length of the misaligned area is longer than 40 mm, the axial length of the second solid section 41 is too long. The axial length of the narrow flow channel formed by the second solid section 41 and the inner wall of the container 20 is too long, resulting in an excessive flow obstruction effect, which affects the concentrate discharge efficiency and thus the overall filtration rate.

[0093] As attached Figure 3 As shown, the width of the radial gap between the axial end of the first solid segment 31 and the inner wall of the container 20 is d1. The position of the minimum distance between the first liquid inlet 22 and the second end 112 of the multiple hollow fiber membrane filaments 11 is the reference point. The width of the radial gap between the first solid segment 31 and the reference point is d2, which satisfies the following conditions: 0 < d1 < d2; d1 / d2 = 0.4-0.6.

[0094] The above ratio range makes the part of the raw solution that does not enter the first inner core 30 narrow the corresponding flow channel during the upward flow, and the flow area becomes smaller, which increases the flow resistance of the liquid flowing from the gap around the outer periphery of the first solid section 31 to the cavity above the first inner core 30 to a certain extent, and the increased flow resistance is appropriate, which promotes more raw solution to enter the first inner core 30 through the first flow-through section 32, improves the utilization rate of the hollow fiber membrane filaments 11 inside the first inner core 30, and a proper amount of raw solution flows axially upward through the flow channel around the outer periphery of the first solid section 31 to reach the cavity above the first inner core 30, which is filtered by the area above the first inner core 30 where the hollow fiber membrane filaments 11 are located, which is equivalent to proper distribution of the raw solution, full use of each part of the hollow fiber membrane filaments 11, and acceleration of the filtration rate. Moreover, due to the decrease in flow velocity of the raw solution outside the first inner core 30 during upward flow, the area of the outer ring of the hollow fiber membrane filaments 11 corresponding to the axial end of the first inner core 30 is also subjected to the flow impact strength of the raw solution, which is also decreased.

[0095] If the above ratio is less than 0.4, the gap between the end of the first solid section 31 and the inner wall of the container 20 is too narrow, the flow resistance is too large, a large amount of raw solution enters the first inner core 30 through the first flow-through section 32, but the flow-through area of the first inner core 30 is limited, the flow of the raw solution is blocked, and the overall flow rate is reduced; if the above ratio is greater than 0.6, the gap between the end of the first solid section 31 and the inner wall of the container 20 is too large, which will reduce the amount of raw solution flowing into the inside of the first inner core 30, resulting in a decrease in the utilization rate of the area inside the first inner core 30 where the hollow fiber membrane filaments 11 are located.

[0096] As shown in Figure 4 , the concentrated solution below the second inner core 40 will flow upward from the gap between the end of the second solid section 41 and the inner wall of the container 20, and then flow to the liquid outlet and be discharged. The radial gap between the axial end of the second solid section 41 and the inner wall of the container 20 has a width d3, and the position where the minimum distance between the second liquid outlet 23 and the first end 111 of the plurality of hollow fiber membrane filaments 11 is located is taken as the reference point. The radial gap between the second solid section 41 and the reference point has a width d4, which satisfies the following conditions: 0 < d3 < d4; d3 / d4 = 0.4-0.6.

[0097] Within the aforementioned ratio range, the width d3 of the end of the second solid section 41 furthest from the outlet is smaller, resulting in a smaller flow channel area. This increases flow resistance to some extent, causing more concentrate to flow into the interior of the second inner core 40 and continue to be filtered by the membrane fiber 11 located within the second inner core 40. This reduces the amount of raw liquid flowing directly to the outlet through the gaps around the outer periphery of the second solid section 41, thus reducing the amount of concentrate requiring secondary recirculation and improving filtration efficiency. On the other hand, the flow channel between the second solid section 41 and the inner wall of the container 20 ensures sufficient space for the concentrate to flow to the outlet. By controlling the ratio within the aforementioned range, sufficient space for concentrate flow is ensured, guaranteeing a sufficiently high discharge rate of the concentrate around the outer periphery of the second inner core 40 and thus ensuring a sufficiently high filtration rate.

[0098] If d3 / d4 is less than 0.4, the flow resistance of the concentrated liquid below the second inner core 40 axis to the outlet will be too large, and the overall filtration rate will decrease. If d3 / d4 is greater than 0.6, more unfiltered raw liquid will flow to the outlet with the concentrated liquid and be discharged, increasing the amount of liquid that needs to be recycled and reducing the filtration efficiency.

[0099] like Figure 3 As shown, the flow cross-sectional area of ​​the first liquid inlet 22 is S1, and the area of ​​the radial gap between the first solid section 31 and the first flow section 32 and the inner wall of the container 20 is S2, which is the cross-sectional area of ​​the flow channel on the outer periphery of the first inner core 30 (excluding the adhesive section 33). It should be noted that the area S2 of the radial gap between the first solid section 31 and the first flow section 32 and the inner wall of the container 20 refers to the area of ​​several cross-sections of the flow channel between the outer wall of the entire first inner core 30 (excluding the adhesive section 33) and the inner wall of the container 20. If the inner diameter of the inner wall of the container 20 corresponding to the first solid section 31 is not constant, S2 is also not constant and will change with the change of the cross-sectional position. If the inner diameter of the inner wall of the container 20 corresponding to the first solid section 31 is constant, S2 can be constant.

[0100] S2 / S1 = 0.8-2.2, meaning that the flow area of ​​the raw liquid from the first inlet 22 to the outer periphery of the first inner core 30 does not change much. Due to the small flow fluctuation caused by the change in flow area, the flow velocity fluctuation of the raw liquid is small during the process of flowing from the first inlet 22 into the outer periphery of the first inner core 30. The fluid flow state is relatively stable, and the impact of the fluid flow on the outer membrane filaments 11 is low, which better protects the outer membrane filaments 11 and also reduces the impact of the fluid flow on the first inner core 30, especially reducing the impact on the first solid section 31 at the end of the first inner core 30. This reduces the shaking of the first inner core 30 relative to the container 20 or the potting part 12 and protects the adhesion performance between the first inner core 30 and the potting part 12.

[0101] Similarly, as attached Figure 4As shown, the flow area of the second liquid outlet 23 is defined as S3, and the area of the radial gap between the second solid section 41 and the first flow section 32 and the inner wall of the container 20 is defined as S4, i.e. the cross-sectional area of the flow passage between the outer periphery of the second inner core 40 (except the bonding section 33) and the inner wall of the container 20, S4 / S3 = 0.8-2.2, i.e. during the process of flowing from the outer periphery of the second solid section 41 to the liquid outlet, the flow passage area of the entire flow path changes little, and during the process of flowing from the outer periphery of the second inner core 40 to the liquid outlet, the flow state of the fluid is stable, the flow impact on the second inner core 40 and the membrane filaments 11 of the outer ring is small, and the bonding performance between the second inner core 40 and the potting portion 12 is protected, and the membrane filaments 11 of the outer ring are protected.

[0102] As shown in the accompanying drawings, Figure 2 In this embodiment, the first inner core 30 and the second inner core 40 each have a bonding section 33. Specifically, the first inner core 30 has a bonding section 33 at the end of the first flow section 32 away from the first solid section 31, and the second inner core 40 has a bonding section 33 at the end of the second flow section 42 away from the second solid section 41. Each bonding section 33 is inserted into the corresponding potting portion 12. The axial length of the bonding section 33 is L5, and the axial length of the potting portion 12 is L6. The following conditions are met: L5 / L6 = 0.3-0.7.

[0103] As shown in the accompanying drawings, Figure 3 and Figure 4 As shown in the accompanying drawings, the first inner core 30 and the second inner core 40 are partially inserted into the corresponding potting portion 12. The first end 111 of the hollow fiber membrane filament 11 is fixedly connected to the first inner core 30 and the inner wall of the container 20 through the potting portion 12, and the second end 112 of the hollow fiber membrane filament 11 is fixedly connected to the second inner core 40 and the inner wall of the container 20 through the potting portion 12. The bonding section 33 represents the area where the first inner core 30 or the second inner core 40 is inserted into the corresponding potting portion 12. The ratio of the axial length of the bonding section 33 to the potting portion 12 is within the above range, so that the potting portion 12 has a portion that is not inserted by the first inner core 30 or the second inner core 40. The potting portion 12 of this portion is not divided into inner and outer regions by the first inner core 30 or the second inner core 40, but is bonded as a whole around the hollow fiber membrane filament 11, has greater mechanical strength, and has greater bonding strength with the inner wall of the container 20, which is conducive to improving the connection stability of the first inner core 30, the second inner core 40, the potting portion 12, and the inner wall.

[0104] If L5 / L6 is less than 0.3, the first inner core 30 or the second inner core 40 is inserted too shallowly into the filling part 12. Under the action of liquid flow pressure and impact force, the first inner core 30 or the second inner core 40 is prone to shaking relative to the filling part 12, causing the filling part 12 to detach from the first inner core 30 or the second inner core 40. If the ratio is greater than 0.7, the first inner core 30 or the second inner core 40 is inserted too deeply into the filling part 12, which damages the integrity and mechanical strength of the filling part 12, and thus affects the connection strength between the first inner core 30, the second inner core 40, the filling part 12 and the inner wall of the container 20.

[0105] As attached Figure 3 and attached Figure 4 As shown, the bonding section 33 of the first inner core 30 and the second inner core 40 includes an annular non-porous region 331. The non-porous region 331 is located at the axial head end of the first inner core 30 and the second inner core 40, and is relatively far away from the first solid section 31 and the second solid section 41. The function of the non-porous region 331 is to improve the mechanical strength of the first inner core 30, to provide radial constraint and clamping effect on the part of the potting part 12 located inside the first inner core 30 and the hollow fiber membrane filament 11 inside it, and at the same time to increase the bonding area between the first inner core 30 and the potting part 12, thereby improving the bonding strength.

[0106] In some embodiments, the axial length of the non-porous region 331 is not less than 10%L5. The potting portion 12 and the non-porous region 331 have a large bonding area and bonding strength, reducing the possibility of the potting portion 12 wobbling relative to the first inner core 30. To a certain extent, the thickness of the potting portion 12 can be reduced, thereby allowing the hollow fiber membrane filament 11 to have more areas not covered by the potting portion 12, resulting in higher filtration efficiency. In a specific embodiment, the axial length of the non-porous region 331 is equal to that of the bonding section 33, that is, the entire bonding section 33 is without openings.

[0107] Of course, in some other embodiments, the bonding section 33 also includes an opening area 332, which is located between the non-porous area 331 and the first flow section 32. The potting part 12 is bonded to both the opening area 332 and the non-porous area 331. Part of the adhesive of the potting part 12 is embedded in the through hole on the opening area 332, forming a connection similar to a bridge. The combination of the two results in a higher bonding strength while ensuring the bonding area between the potting part 12 and the first inner core 30.

[0108] It should be noted that the through hole in the non-porous area 332 of the adhesive section 33 is not the same as the flow hole in the first flow section 32. Their functions are different. Moreover, the through hole in the non-porous area 332 of the adhesive section 33 is inserted into the potting part 12, while the flow hole in the first flow section 32 is exposed outside the potting part 12.

[0109] like Figure 2 , Figure 5 and Figure 6As shown, the axial end of the first inner core 30 is axially fixed with the container 20, specifically, the container 20 comprises a barrel 25 and two end covers 26, the outer periphery of the axial end of the first solid section 31 is provided with a plurality of clamping lugs 34 which are circumferentially spaced, the end face of the clamping lug 34 is flush with the end face of the first solid section 31, the clamping lug 34 is inserted between the barrel body and one side end cover 26 and clamped and fixed by the two, thereby fixing the first inner core 30, the space between adjacent clamping lugs 34 is also part of the raw liquid cavity 211, which can guide the to-be-filtered liquid to be evenly distributed in the raw liquid cavity 211 and fully contact with the hollow fiber membrane filaments 11; while the first solid section 31 provides a setting position for the clamping lug 34 and ensures the structural strength of the clamping lug 34, avoiding the first inner core 30 and the hollow fiber membrane bundle 10 from shaking relative to the container 20, so as to protect the hollow fiber membrane filaments 11.

[0110] Similarly, as shown in the figure, Figure 2 The outer periphery of the second solid section 41 of the second inner core 40 is provided with a plurality of clamping lugs 34 which are circumferentially spaced, the clamping lug 34 is inserted between the barrel body 25 and the other side end cover 26 and clamped and fixed by the two, thereby fixing the second inner core 40.

[0111] The above-mentioned embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application, any non-essential changes and replacements made by those skilled in the art on the basis of the present application shall fall within the scope of protection of the present application.

Claims

1. A hollow fiber module, comprising: a hollow fiber membrane bundle comprising a plurality of hollow fiber membrane filaments and two potting portions confining axially opposite first and second ends of the hollow fiber membrane filaments, at least one of the first and second ends of the plurality of hollow fiber membrane filaments being open; a container comprising a receiving cavity, a first liquid inlet, a second liquid inlet and a filtrate outlet, the hollow fiber membrane bundle being axially fixed in the receiving cavity, and the two potting portions being sealingly fixed to the inner wall of the container; a region of the receiving cavity corresponding to a region between the two potting portions is a stock solution cavity, the first and second liquid inlets are located at axially opposite ends of the stock solution cavity and correspond to the first and second ends of the plurality of hollow fiber membrane filaments respectively, and both of the first and second liquid inlets communicate with the stock solution cavity; and the filtrate outlet is located at an axial end of the receiving cavity, and a region of the receiving cavity corresponding to a region between the filtrate outlet and the corresponding potting portion is a filtrate cavity; characterized in that the hollow fiber module further comprises at least a first inner core surrounding the first ends of the plurality of hollow fiber membrane filaments, the first inner core being fixed relative to the container and having a first flow-through section corresponding to the first liquid inlet, the first flow-through section being provided with a plurality of flow-through holes; a first solid section of the first flow-through section of the first inner core away from one end of the corresponding potting portion is formed to be non-porous, and a minimum distance between the first liquid inlet and the second ends of the plurality of hollow fiber membrane filaments is L2, and a minimum distance between the first flow-through section of the first inner core and the second ends of the plurality of hollow fiber membrane filaments is L1, satisfying the condition L1 > L2.

2. The hollow fiber module of claim 1, wherein, an axial length of the first solid section is 30-35% of an axial total length of the first inner core; and / or an axial length of the first flow-through section is 40-50% of the axial total length of the first inner core.

3. The hollow fiber module of claim 1 or 2, wherein, an axial length L3 of a region of the first solid section directly opposite the first liquid inlet is L1-L2, an axial length of the first solid section is L4, and the condition L3 ≤ 30% L4 is satisfied; and / or L4-L3 = 15-40 mm.

4. The hollow fiber module of claim 1, wherein, a width of a radial gap between an axial end of the first solid section and the inner wall of the container is d1, a position where the minimum distance between the first liquid inlet and the second ends of the plurality of hollow fiber membrane filaments is located is a reference point, a width of a radial gap between the first solid section and the reference point is d2, and the condition 0 < d1 < d2 is satisfied; and d1 / d2 = 0.4-0.

6.

5. The hollow fiber module of claim 1, wherein, a flow-through cross-sectional area of the first liquid inlet is S1, and an area of a radial gap between the first solid section and the first flow-through section and the inner wall of the container is S2, and the condition S2 / S1 = 0.8-2.2 is satisfied.

6. The hollow fiber module of claim 1, wherein, the first inner core has a bonding section at an end of the first flow-through section away from the first solid section, the bonding section is inserted into the potting portion, an axial length of the bonding section is L5, and an axial length of the potting portion is L6, and the condition L5 / L6 = 0.3-0.7 is satisfied; and / or an outer periphery of the axial end of the first solid section is axially fixed to the container by a plurality of clamping lugs arranged at a circumferential interval.

7. The hollow fiber module of claim 6, wherein, an end of the bonding section away from the first flow-through section has a non-porous annular region.

8. The hollow fiber module of claim 7, wherein, The axial length of the non-porous region is not less than 10% L5.

9. The hollow fiber module of claim 7, wherein, The bonding section further comprises an open-pore region between the non-porous region and the first flow-through section.

10. The hollow fiber module of any one of claims 1 or 2 or 4 to 9, wherein, A second inner core surrounding the second ends of the plurality of hollow fiber membrane filaments is further included, the second inner core being fixed relative to the container, the second inner core having the second flow-through section and the second solid section, the second flow-through section corresponding to the second liquid passage, and the minimum distance between the second flow-through section of the second inner core and the first ends of the plurality of hollow fiber membrane filaments being H1, the minimum distance between the second liquid passage and the first ends of the plurality of hollow fiber membrane filaments being H2, satisfying the condition H1>H2.

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