Mixing hollow fiber sizes to improve humidifier performance

Abstract

A fluid transfer element is provided for use as a humidifier in fuel cell applications, for transferring moisture from humid exhaust air to dry air flowing in from the surroundings. This element has a hollow membrane tube arrangement structure, also called a hollow membrane thread, which has a passage through the tube and another passage around the tube through the gap between the outer surfaces of adjacent tubes. The hollow membrane tube arrangement structure has tubes with different flow cross-sectional areas, which can be provided by large-diameter and small-diameter tubes arranged to provide different flow limiting characteristics. The tubes can be arranged to reduce pressure drop and to guide the humid gas airflow into smaller gaps along the humid air flow path.

Description

Technical Field

[0001] Cross-Reference to Related Patent Applications This patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 683,754 filed on August 16, 2024 and U.S. Provisional Patent Application No. 63 / 535,140 filed on August 29, 2023. The entire teachings and disclosures of each of these applications are incorporated herein by reference.

[0002] The present invention generally relates to a fluid transfer device that can be embodied, for example, as a humidifier, and more specifically relates to mixing of hollow fiber sizes in such a fluid transfer device.

Background Art

[0003] Humidifiers play an important role in optimizing the performance of hydrogen PEM fuel cells. Humidifiers help control the moisture content of incoming reactive gases such as hydrogen and air. By regulating the humidity of the reactive gases, the humidifier ensures that the fuel cell operates at the best efficiency. Maintaining an appropriate moisture level facilitates the ion conduction process in the electrolyte of the fuel cell and promotes efficient electrochemical reactions. This ultimately leads to improvements in the overall performance, power output and service life of the fuel cell.

[0004] One known form of humidifier, comprising an annular filter filled with tubular membrane threads, is shown and described by Duryea in WO2023028037 under the invention title "Fuel Cell Humidification Potting Adhesive Shroud". According to Duryea, a separation element and / or humidification element is disclosed that uses a single annular bundle of filamentous hollow membrane tubes, which can be used, for example, for humidifying reaction gases, for water vapor transfer between different gas flows in fuel cell applications. At least one, typically two, composite end caps seal the ends of the bundle of filamentous hollow membrane tubes. Each composite end cap comprises an adhesive (e.g., epoxy) and a preform, e.g., an annular shroud made of plastic.

[0005] Another different configuration of a humidifier having a cylindrical bundle of tubular membrane fibers is shown in US Patent No. 8,317,167 by Kim, under the invention title "Humidifier For Fuel Cell". The above-mentioned '167 patent by Kim discloses a humidifier for a fuel cell in which multiple hollow fiber membranes have different diameters and are arranged to control the direction of the flow of dry air introduced into the humidifier. However, the arrangement structure of the above-mentioned '167 patent by Kim does not take into account the effect of the wet airflow, and in particular it appears that the wet airflow is more difficult to reach the center of the cylindrical bundle of tubular membrane fibers having tubes of smaller diameter. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2023028037 [Patent Document 2] U.S. Patent No. 8,317,167 [Overview of the project]

[0007] The present application and its embodiments offer the possibility of improving moisture transport at low cost under all constraints.

[0008] To enhance moisture transfer while using hollow fiber membranes, it is necessary to increase the contact surface area for exchange between the dry and wet sides of the humidifier. For this purpose, more fibers can be used for the same volume flow, or fewer fibers can be used for the same volume flow. Both of these have a high cost in terms of pressure on the fiber side (e.g., dry air flow) or shell side (e.g., wet air flow) of the humidifier. The solution provided herein enables a method of mixing the fiber diameters used in the humidifier, thereby obtaining a clear advantage in moisture transfer, in which case the pressure difference cost increases only moderately overall.

[0009] The following design improves moisture transfer between the wet and dry sides of a humidifier with minimal cost associated with flow limiting. This design incorporates mixed hollow fiber diameters distributed throughout the humidifier to enhance humidification capacity.

[0010] The flow passing through the yarn side (e.g., dry flow) has a pressure drop due to the number of yarns and the inner diameter of the yarns. The flow passing through the outside (shell side, e.g., moist air flow) has a pressure drop due to the number of yarns and the outer diameter of the yarns. The number of yarns and yarn diameters determine the surface area available for moisture exchange and good moisture transport. Rather than replacing all yarn diameters to increase the surface area (and thereby increase moisture transport), the yarn diameters can be appropriately mixed in the humidifier to obtain improved performance.

[0011] In one embodiment, the humidifier includes a filter element (i.e., a fluid transfer element) having an assembly of tubular threads arranged in an annular arrangement parallel to the direction of the fluid flow through the humidifier. The tubular threads have at least two different diameters and optionally at least three different diameters.

[0012] The tubular threads may be arranged in a continuous circumferential pattern D1, D2, Dn... of different thread diameters, or they may be grouped and arranged in other ways.

[0013] The filling volume of a humidifier can be evenly divided among different yarn sizes. For example, if a humidifier has a filling rate of 32% with two yarn diameters (filling volume = %) of the cross-section containing the yarn, then 16% of D1 yarn and 16% of D2 yarn may be present.

[0014] In another embodiment, the fluid transfer element can be divided into different assemblies of hollow membrane tubes, and these assemblies can be arranged in a parallel fluid circuit (for example, the fluid can flow through one assembly or the other, and does not need to flow through both assemblies, as in the case of a series fluid circuit). In this embodiment, the different assemblies have different average flow cross-sectional areas of the hollow membrane tubes.

[0015] In another embodiment, the fluid transfer element can be divided into different assemblies of hollow membrane tubes by different cartridges that can be used together. In this embodiment, the different cartridges have assemblies of hollow membrane tubes with different average flow cross-sectional areas.

[0016] According to one inventive aspect of the present invention, a fluid transfer element is provided, having a hollow membrane tube arrangement structure, the arrangement structure comprising (a) a first flow path defined by the hollow membrane tubes; and (b) a second flow path running separately from the first flow path and through a gap defined between adjacent members of the hollow membrane tubes, the second flow path having a second flow path running between an inlet region and an outlet region. The hollow membrane tube arrangement structure comprises tubes having different flow cross-sectional areas arranged to provide different flow limiting characteristics, and includes a first assembly of hollow membrane tubes, the first assembly having a smaller average flow cross-sectional area than a second assembly of hollow membrane tubes. The first assembly of hollow membrane tubes is arranged along the second flow path to receive a larger pressure drop than the second assembly of hollow membrane tubes.

[0017] The various features described below (or above) may be used individually or in various combinations with the inventive aspects described above.

[0018] One characteristic feature is that the first assembly of hollow membrane tubes is also positioned along the first flow path to experience a greater pressure drop than the second assembly of hollow membrane tubes.

[0019] One feature is that the fluid transfer element is incorporated into an assembly, the assembly further having a housing that defines an element cavity for housing the fluid transfer element. The housing further has: a first pair of fluid ports comprising a first inlet and a first outlet, with a first flow path arranged to flow between the first pair of fluid ports; and a second pair of fluid ports comprising a second inlet and a second outlet, with a second flow path arranged to flow between the second pair of fluid ports, the second inlet communicating with an inlet region and the second outlet communicating with an outlet region.

[0020] Such an assembly may further include a housing body and a removable lid, which is removable to allow for the replacement of the fluid transfer element.

[0021] In such an assembly, the housing may further have a rectangular box-shaped structure having six faces defining the element cavity, with the first inlet and first outlet aligned along a single common face among the six faces; and / or the second inlet and second outlet aligned along a single common face among the six faces. Preferably, each of the first inlet, first outlet, second inlet, and second outlet is aligned along a single common face among the six faces.

[0022] One feature is that the fluid transfer element may be divided into separate cartridges, each containing a first cartridge and a second cartridge that are spaced apart. Each cartridge may have a first cap and a second cap, each spaced apart, with a tightly engaged assembly of hollow membrane tubes within each of these caps. For example, the first cartridge may have a first assembly of hollow membrane tubes, and the second cartridge may have a second assembly of hollow membrane tubes.

[0023] In one embodiment, one feature is that the arrangement structure of the hollow membrane tube surrounds a central open cavity. For example, the fluid transfer element may further have a pair of end caps at opposing ends of this arrangement structure, one of which has an opening communicating with the central open cavity, and the second flow path extends radially between the central open cavity and the outer perimeter surrounding the arrangement structure.

[0024] In the above-described features, the arrangement structure of the hollow membrane tubes may have a set of hollow membrane tubes having different flow cross-sectional areas, including at least a first annular region and a second annular region.

[0025] In the arrangement of features described above, the first annular region may be located radially inward of the second annular region, and has hollow membrane tubes of the first annular region with an average flow cross-sectional area larger than that of the hollow membrane tubes of the second annular region. Optionally, the arrangement may further comprise a third annular region of hollow membrane tubes radially outward of the second annular region, and the third annular region has hollow membrane tubes of the third annular region with an average flow cross-sectional area larger than that of the hollow membrane tubes of the second annular region.

[0026] According to another inventive aspect of the present invention, there is provided a fluid transfer element having an arrangement of hollow membrane tubes, the arrangement comprising: (a) a first flow path defined by the hollow membrane tubes; and (b) a second flow path extending separately from the first flow path and extending through gaps defined between adjacent members of the hollow membrane tubes, the second flow path extending between an inlet region and an outlet region. Furthermore, the fluid transfer element may be provided by a plurality of cartridges including a first cartridge and a second cartridge in a spaced relationship. Each cartridge has a first cap and a second cap that are spaced apart from each other, and an assembly of hollow membrane tubes is tightly engaged in each of these caps. The first cartridge has a first assembly of hollow membrane tubes, the second cartridge has a second assembly of hollow membrane tubes, and the first assembly of hollow membrane tubes has an average flow cross-sectional area smaller than that of the second assembly of hollow membrane tubes.

[0027] Various features described below (or described above) may be used alone or in various mutual combinations with the inventive aspects described above.

[0028] In the aspect described above, preferably, all of the hollow membrane tubes of the first cartridge have a common size and / or all of the hollow membrane tubes of the second cartridge have a common size, but alternatively, a mixture of tubes of different sizes may be used in a single cartridge.

[0029] In the above embodiment, one feature is that the first assembly of hollow membrane tubes is also positioned along the first flow path to experience a greater pressure drop than the second assembly of hollow membrane tubes.

[0030] In the above embodiment, one feature is that each cartridge has a side wall with a window near each end cap, the window communicating with a second flow path through this window.

[0031] In the above embodiment, the plurality of cartridges further include a third cartridge that is spaced apart from the first and second cartridges, and one feature is that the second cartridge is inserted between the first and third cartridges. The third cartridge has a third assembly of hollow membrane tubes, the third assembly of hollow membrane tubes having a larger average flow cross-sectional area than the first and second assemblies of hollow membrane tubes.

[0032] In the above embodiment, the fluid transfer element may be incorporated into an assembly, the assembly further having a housing that defines an element cavity for housing the fluid transfer element. The housing may have: a first pair of fluid ports comprising a first inlet and a first outlet, with a first flow path arranged to flow between the first pair of fluid ports; and a second pair of fluid ports comprising a second inlet and a second outlet, with a second flow path arranged to flow between the second pair of fluid ports, the second inlet communicating with an inlet region and the second outlet communicating with an outlet region.

[0033] Such an assembly may further include a housing body and a removable lid, which is removable to allow for the replacement of the fluid transfer element.

[0034] In such an assembly, the housing may further have a rectangular box-shaped structure having six faces defining the element cavity, with the first inlet and first outlet aligned along a single common face among the six faces; and / or the second inlet and second outlet aligned along a single common face among the six faces. Preferably, each of the first inlet, first outlet, second inlet, and second outlet is aligned along a single common face among the six faces.

[0035] According to another inventive aspect of the present invention, a fluid transfer element is provided, having a hollow membrane tube arrangement structure, the arrangement structure comprising (a) a first flow path defined by the hollow membrane tubes; and (b) a second flow path that passes separately from the first flow path and through a gap defined between adjacent members of the hollow membrane tubes, the second flow path having a second flow path that passes between an inlet region and an outlet region. Furthermore, the hollow membrane tube arrangement structure comprises tubes having different flow cross-sectional areas, including a first assembly of hollow membrane tubes and a second assembly of hollow membrane tubes, the first assembly of hollow membrane tubes having a smaller average flow cross-sectional area than the second assembly of hollow membrane tubes, and furthermore, the first and second assemblies of hollow membrane tubes are arranged in a fluid circuit parallel to the second flow path.

[0036] The various features described below (or above) may be used individually or in various combinations with the inventive aspects described above.

[0037] One feature of the above embodiment is that at least one partition wall is provided between the first and second assemblies of the hollow membrane tubes.

[0038] One feature of the above embodiment is that the fluid transfer element is provided by a plurality of cartridges, including a first cartridge and a second cartridge. Each cartridge has a spaced-apart first cap and a second cap, within which an assembly of hollow membrane tubes is tightly engaged, the first cartridge having a first assembly of hollow membrane tubes, and the second cartridge having a second assembly of hollow membrane tubes.

[0039] In the above embodiment, one feature is that the first assembly of hollow membrane tubes is also positioned along the first flow path to experience a greater pressure drop than the second assembly of hollow membrane tubes.

[0040] One feature of the above embodiment is that the second assembly of hollow membrane tubes is positioned further downstream relative to the first assembly of hollow membrane tubes along the second flow path.

[0041] One feature of the above embodiment is the provision of a third assembly of hollow membrane tubes. The third assembly of hollow membrane tubes has a larger average flow cross-sectional area than the first and second assemblies of hollow membrane tubes.

[0042] In the above configuration, the third assembly may be located in a parallel fluid circuit that includes the first and second assemblies.

[0043] In the above embodiment, the fluid transfer element may be incorporated into an assembly, the assembly further having a housing that defines an element cavity for housing the fluid transfer element. The housing may have: a first pair of fluid ports comprising a first inlet and a first outlet, with a first flow path arranged to flow between the first pair of fluid ports; and a second pair of fluid ports comprising a second inlet and a second outlet, with a second flow path arranged to flow between the second pair of fluid ports, the second inlet communicating with an inlet region and the second outlet communicating with an outlet region.

[0044] Such an assembly may further include a housing body and a removable lid, which is removable to allow for the replacement of the fluid transfer element.

[0045] In such an assembly, the housing may further have a rectangular box-shaped structure having six faces defining the element cavity, with the first inlet and first outlet aligned along a single common face among the six faces; and / or the second inlet and second outlet aligned along a single common face among the six faces. Preferably, each of the first inlet, first outlet, second inlet, and second outlet is aligned along a single common face among the six faces.

[0046] According to another inventive aspect of the present invention, a fluid transfer element is provided, having a hollow membrane tube arrangement structure, the arrangement structure comprising (a) a first flow path defined by the hollow membrane tubes; and (b) a second flow path that passes separately from the first flow path and through a gap defined between adjacent members of the hollow membrane tubes, the second flow path having a second flow path that passes between an inlet region and an outlet region. Furthermore, the hollow membrane tube arrangement structure comprises tubes having different flow cross-sectional areas, including a first assembly of hollow membrane tubes and a second assembly of hollow membrane tubes, the first assembly of hollow membrane tubes having a smaller average flow cross-sectional area than the second assembly of hollow membrane tubes, and the first assembly of hollow membrane tubes being closer to the inlet region of the second flow path than the second assembly.

[0047] The various features described below (or above) may be used individually or in various combinations with the inventive aspects described above.

[0048] One feature of the above embodiment is that the first assembly of hollow membrane tubes is arranged along the first flow path such that it experiences a larger pressure drop than the second assembly of hollow membrane tubes.

[0049] In the above embodiment, the fluid transfer element may be incorporated into an assembly, the assembly further having a housing that defines an element cavity for housing the fluid transfer element. The housing may have: a first pair of fluid ports comprising a first inlet and a first outlet, with a first flow path arranged to flow between the first pair of fluid ports; and a second pair of fluid ports comprising a second inlet and a second outlet, with a second flow path arranged to flow between the second pair of fluid ports, the second inlet communicating with an inlet region and the second outlet communicating with an outlet region.

[0050] Such an assembly may further include a housing body and a removable lid, which is removable to allow for the replacement of the fluid transfer element.

[0051] In such an assembly, the housing may further have a rectangular box-shaped structure having six faces defining the element cavity, with the first inlet and first outlet aligned along a single common face among the six faces; and / or the second inlet and second outlet aligned along a single common face among the six faces. Preferably, each of the first inlet, first outlet, second inlet, and second outlet is aligned along a single common face among the six faces.

[0052] In the above embodiment, one feature is that the fluid transfer element is divided into separate cartridges, each containing a first cartridge and a second cartridge that are spaced apart. Each cartridge may have a first cap and a second cap, each spaced apart, with an assembly of hollow membrane tubes tightly engaged within each of these caps. The first cartridge may have a first assembly of hollow membrane tubes, and the second cartridge may have a second assembly of hollow membrane tubes.

[0053] In the above embodiment, one feature is that the arrangement structure of the hollow membrane tube surrounds a central open cavity. The fluid transfer element may further have a pair of end caps at opposite ends of the arrangement structure, one of which has an opening communicating with the central open cavity. A second flow path may extend radially between the central open cavity and the outer perimeter surrounding the arrangement structure. The arrangement structure of the hollow membrane tube has a tube having different flow cross-sectional areas including at least a first annular region and a second annular region.

[0054] In the above-described features, the first annular region may be radially inward of the second annular region and has a hollow membrane tube of the first annular region with a larger average flow cross-sectional area than the hollow membrane tube of the second annular region.

[0055] In one or both of the above two characteristics, the third annular region of the hollow membrane tube may be radially outward of the second annular region, and the hollow membrane tube of the third annular region has a larger average flow cross-sectional area than the hollow membrane tube of the second annular region.

[0056] According to another inventive aspect of the present invention, the fluid transfer element has an arrangement structure of hollow membrane tubes in a ring structure surrounding a central open cavity, with a pair of end caps at opposing ends of this arrangement structure. One of these end caps has an opening that communicates with the central open cavity. A first flow path is defined by the hollow membrane tubes; a second flow path runs separately from the first flow path and is defined by gaps defined between adjacent members of the hollow membrane tubes. The second flow path runs radially between the central open cavity and the outer perimeter surrounding the arrangement structure. Furthermore, the arrangement structure of hollow membrane tubes has tubes having different flow cross-sectional areas.

[0057] The various features described below (or above) may be used individually or in various combinations with the inventive aspects described above.

[0058] The arrangement structure of the hollow membrane tubes includes a first assembly of hollow membrane tubes and a second assembly of hollow membrane tubes, wherein the first assembly of hollow membrane tubes has a smaller average flow cross-sectional area than the second assembly of hollow membrane tubes.

[0059] In the above embodiment, one characteristic of the arrangement structure of the hollow membrane tube is that it has a first annular region of the hollow membrane tube, and the first annular region has a different average flow cross-sectional area from the second annular region of the hollow membrane tube.

[0060] In the above characteristics, the first annular region may be radially inward of the second annular region, and the first annular region has a first average flow cross-sectional area of ​​the hollow membrane tube that is larger than the second average flow cross-sectional area of ​​the hollow membrane tube of the second annular region.

[0061] The above features may further include a third intermediate annular region of the hollow membrane tube, which lies radially outward from the second annular region. The third annular region may have a third average flow cross-sectional area of ​​the hollow membrane tube that is larger than the second average flow cross-sectional area.

[0062] Furthermore, the above features may include a fourth intermediate annular region of the hollow membrane tube, which is located radially outside the third annular region. The fourth annular region may have a fourth average flow cross-sectional area of ​​the hollow membrane tube that is smaller than the third average flow cross-sectional area.

[0063] In the above embodiment, the first annular region provides the innermost region that directly surrounds the central cavity, and optionally, a tubular support cage is provided within the central cavity.

[0064] In the above embodiment, one feature is that the fluid transfer element is incorporated into an assembly, the assembly further having a housing that defines an element cavity for housing the fluid transfer element. This housing further has: a first pair of fluid ports comprising a first inlet and a first outlet, and having a first flow path arranged to flow between the first pair of fluid ports; and a second pair of fluid ports comprising a second inlet and a second outlet, and having a second flow path arranged to flow between the second pair of fluid ports. The second inlet communicates with the inlet region of the fluid transfer element, and the second outlet communicates with the outlet region of the fluid transfer element. The inlet region is provided by an annular chamber surrounding the outer periphery of the outermost annular region of the hollow membrane tube, or by a central open cavity.

[0065] Another inventive embodiment which may have one or more of the above embodiments and / or features is a humidifier for a fuel cell, in which the humidifier includes a filter element (also called a fluid transfer element) having an array of tubular threads (e.g., hollow membrane tubes) arranged parallel to the direction of the fluid flow through the humidifier, the tubular threads having at least two different thread diameters.

[0066] In the above embodiment of the humidifier, the tubular thread may have at least three different thread diameters.

[0067] In the above-described embodiment of the humidifier, the tubular threads may be arranged in a continuous circumferential pattern D1, D2, Dn... of different thread diameters.

[0068] In the above-described embodiment of the humidifier, the humidifier typically includes an annular collection of tubular threads.

[0069] In the above embodiment of the humidifier, the tubular thread has at least two different inner diameters.

[0070] In the above embodiment of the humidifier, the tubular thread has at least two different outer diameters.

[0071] Additional features usable in various different inventive embodiments The additional features described below (or above) may be used alone or in combination in any of the various different inventive embodiments and features described above.

[0072] One feature of the fluid transfer element is that it further has a first cap and a second cap, within which a hollow membrane tube is tightly engaged. Furthermore, the intermediate portion of the hollow membrane tube between the first end cap and the second end cap is exposed to the second flow path.

[0073] One characteristic of the first assembly of hollow membrane tubes is that it has a first average flow cross-sectional area, which is 10% to 80% of the second average flow cross-sectional area of ​​the second assembly of hollow membrane tubes, and more preferably 20% to 50% of the second average flow cross-sectional area of ​​the second assembly of hollow membrane tubes.

[0074] The hollow membrane tube has an inner diameter / inner width defined as less than 2 mm, preferably 0.4 mm to 1.3 mm, and one characteristic is that the inner diameter / inner width of the second assembly of the hollow membrane tube is at least 0.1 mm, preferably 0.2 mm to 0.8 mm larger than the inner diameter / inner width of the first assembly of the hollow membrane tube.

[0075] One characteristic of hollow membrane tubes with different flow cross-sectional areas is that they have at least three different sizes.

[0076] Preferably, one feature is that the hollow membrane tubes of the first assembly are each of a first common size, and the hollow membrane tubes of the second assembly are each of a second common size. Alternatively, hollow membrane tubes of different sizes may be mixed in each assembly, and the inner diameter / inner width for such an assembly is considered as the average of such a mix.

[0077] Other aspects, purposes, and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings.

[0078] The accompanying drawings incorporated herein and forming part thereof illustrate several aspects of the present invention and are useful in illustrating the principles of the present invention. [Brief explanation of the drawing]

[0079] [Figure 1] This is a schematic flowchart of a fuel cell circuit having a humidifier according to an embodiment of the present invention. [Figure 2]This is an isometric view showing a fluid transfer assembly in the form of a humidifier according to an embodiment of the present invention that can be used in the fuel cell circuit shown in Figure 1. [Figure 3] Figure 2 shows a cross-sectional view of a humidifier, as shown in the diagram, illustrating the flow of moist air into the humidifier along a second flow path, in an embodiment that includes a fluid transfer element having two cartridges providing two assemblies of hollow membrane tubes of different thread sizes. [Figure 4] Figure 2 shows a cross-sectional view of a humidifier as shown in Figure 2, illustrating the flow of (now partially dried) moist air to the outside of the humidifier along a second flow path, using the fluid transfer element according to the embodiment of Figure 3. [Figure 5] A cross-sectional view of a humidifier, as shown in Figure 2, showing the flow of moist air into the humidifier along a second flow path, in another embodiment similar to the embodiment in Figure 3, which has a fluid transfer element having three cartridges providing three assemblies of hollow membrane tubes of different thread sizes. [Figure 6] This is a cross-sectional view of the humidifier showing the flow of (now partially dried) moist air to the outside of the humidifier along a second flow path, using the fluid transfer element according to the embodiment of Figure 5. [Figure 7] Figure 2 is a schematic cross-sectional view of the humidifier shown, primarily to illustrate the fluid flow through the humidifier. [Figure 8] Figure 7 is a schematic cross-sectional view primarily showing the humidifier. [Figure 9] This is a perspective view showing a fluid transfer element having two bundles of hollow fiber membranes and a cartridge. [Figure 10] This is an isometric view showing a fluid transfer element having an assembly of hollow membrane tubes of different sizes in an annular configuration according to another embodiment of the present invention. [Figure 11] Figure 10 is an end view of the fluid transfer element. [Figure 12] Figure 10 is a partial schematic diagram of a cross-section of the fluid transfer element, which is installed within a housing, to provide a humidifier assembly that can be used in the fuel cell circuit of Figure 1. [Figure 13] This is an isometric view showing a portion of an assembly of relatively large-diameter hollow membrane filament tubes that can be used in any of the embodiments shown in Figures 1 to 12. [Figure 14] This figure shows a portion of an assembly of relatively small-diameter hollow membrane filament tubes that can be used in any of the embodiments shown in Figures 1 to 12.

[0080] While the present invention will be described in relation to certain preferred embodiments, it is not intended to limit the invention to these embodiments. Rather, it is intended to cover all alternative forms, modifications, and equivalent forms that fall within the spirit and scope of the invention as defined by the appended claims. [Modes for carrying out the invention]

[0081] Referring to Figure 1, an example of the operating environment is shown in the form of a hollow membrane humidifier 10 in a fuel cell system 12 according to an embodiment of the present invention. The fuel cell system 12 includes an air supply unit for the humidifier 10, in which dry air (e.g., ambient air) is brought in from the external environment by a blower 14, and exhaust air containing humidified air is discharged by a fuel cell 16. As the humidified air discharged by the fuel cell 16 passes through the humidifier 10, the dry intake air for the fuel cell 10 is humidified by the water contained in the fuel cell exhaust gas (i.e., humidified air) as it passes through the hollow membrane humidifier tube (shown in a later figure) of the humidifier 10.

[0082] Referring to Figure 2 (and Figures 3-8), an embodiment of the fluid transfer assembly 20 is shown, which includes a housing 22 for the fluid transfer element 24 (i.e., an assembled collection of hollow membrane tubes as shown in Figure 9). The housing 22 optionally defines an element cavity 24 which can be divided by a partition such as a tube sheet 28 with a cartridge opening 30. In any case, the element cavity 24 houses the fluid transfer element 24.

[0083] The fluid transfer assembly 20 can be used as a humidifier 10 to increase the humidity of the intake air leading to the fuel cell 16, as shown in Figure 1. However, it is understood that the fluid transfer assembly 20 can also be used in other applications to transfer water and / or other selected gases or other fluids between different fluid flows.

[0084] Returning to Figure 2 (and Figures 3-8), the housing 20 has a first pair of fluid ports 32, 34, which are provided with a first passage 36 arranged to flow between them. In particular, these ports include an inlet port 32 for taking in dry air from the surroundings, as shown in Figure 1, for example, and an outlet port 34 for now humidified dry air that can be supplied to the fuel cell, as shown in Figure 1, for example.

[0085] Additionally, the housing has a second pair of fluid ports 38, 40, which include a second flow path 42 arranged to flow between them. In particular, these ports include an inlet port 38 for receiving moist exhaust gas from the fuel cell 16 shown in Figure 1, for example, and an outlet port 40 for discharging the moist exhaust gas (including water vapor reduced by humidification of dry air) after it has passed through the housing 20.

[0086] The fluid transfer element 24 can be permanently mounted within the housing 22 (for example, permanently bonded directly to the housing 22 with adhesive), but more preferably, the fluid transfer element 22 is replaceable, so that the housing can be reused and the fluid transfer element 22 can be replaced if the porosity of the fluid transfer element is more limited by contaminants.

[0087] To achieve this, the housing 22 may have a housing body 44 and a removable lid 46. The lid 46 is removable (for example, by fasteners 48 such as bolts or clamps) to allow replacement of the fluid transfer element 24.

[0088] The other end of the housing body 44 is provided with an end cover 50 that can be optionally removed.

[0089] In this embodiment, the fluid transfer element 22 can be divided into separate cartridges 52, 54, and 56, and these cartridges can be spaced apart with gaps between them as shown in the figure, with each of these cartridges fitting into one of the openings of the partition wall 28.

[0090] Figures 3 and 4 show two cartridges 52 and 54, whereas Figures 5 and 6 show three cartridges 52, 54, and 56. Additionally or alternatively, each individual cartridge can be divided into separate, adjacent cartridges that fit into a single opening (for example, if a single cartridge 52 has a divider inside, multiple cartridges can be efficiently created within such a cartridge 52).

[0091] Each cartridge 52, 54, 56 has a first cap 58 and a second cap 60, respectively, spaced apart, within which an assembly of hollow membrane tubes 62 is tightly engaged. For example, each end cap 58, 60 may contain polyurethane or epoxy, in which the ends of the hollow membrane tubes 62 are potted / molded and fixed in a cut state, and optionally a shroud retainer is provided. This process is further described and illustrated, for example, by Duryea in International Publication No. 2023 / 028037, the entire disclosure of which is incorporated herein by reference.

[0092] For example, the hollow membrane tube 62 may include a hollow polymer yarn with a length of 3 inches to 3 feet (corresponding to the length of element 10). Suitable hollow membrane tubes 62 (e.g., hollow membrane yarns) usable in any of the embodiments described above are generally known to those skilled in the art and can be exemplified by: U.S. Patent Application Publication 2010 / 0190093 by Lee, which discloses a hollow fiber membrane having a first hydrophilic polymer film of tube type having a hollow center and a second hydrophilic polymer film coated on the inner surface of the first hydrophilic polymer film of tube type (for example, U.S. Patent Application Publication 2010 / 0190093 by Lee, which states that the tube may have one or two films (preferably two films) and may be made of polyetherimide (PEI), polyimide (PI), polyamideimide (PAI), polysulfone or polyethersulfone, perfluorinated sulfonic acid copolymer, polyvinyl alcohol (PV A) disclosing a filamentous membrane material that can be manufactured from polyacrylonitrile (PAN); and / or a hollow fiber having water permeability and a microporous structure, manufactured from polysulfone, polycarbonate, polyamide, etc., applicable for exchanging humidity between two fluid flows, i.e., gas to gas or liquid to gas (it is desirable that the membrane's water permeability not exceed 10 ml / hr / mmHg to minimize leakage of water carriers (pure water, humidified gas) into the gas flow to be humidified); and / or a commercially available product as shown in U.S. Patent No. 8,181,943 by Leister et al. and / or Vaperma's Siftek technology (see https: / / www.greencarcongress.com / 2009 / 03 / uop--to-offer-vahtml and European Patent No. 1,651,332 by Cranford et al. / Vaperma, Inc.). Therefore, the patent publications in this paragraph are incorporated by reference in their entirety, as the membrane materials disclosed therein are usable in embodiments of the hollow membrane tube 62 of the present disclosure.

[0093] Suitable adhesives usable in any of the aforementioned embodiments relating to the end caps 58, 60 include, but are not limited to, a variety of epoxys, including two-component epoxys, and a variety of polyurethanes, or other such adhesives that can be applied in the form of a fluid viscous liquid and can cure in situ. End cap adhesives applied in the form of a fluid viscous liquid typically fill the gap between adjacent tubes 62, allowing all or most of the fluid flow to pass through the opposing open ends of the hollow membrane tubes 62, thereby producing the desired effect for moisture separation and exchange purposes. Once the adhesive for the end caps 58, 60 has cured, the ends can then be cut to expose the open ends of the hollow membrane tubes 62, thereby allowing the fluid to move through the tubes.

[0094] In these embodiments, the first cartridge 52 has a first assembly 64 of hollow membrane tubes 62, the second cartridge 54 has a second assembly 68 of hollow membrane tubes 62, and if an optional third cartridge 56 is used, it provides a third assembly 66 of hollow membrane tubes 62.

[0095] As shown in Figures 3 to 9, the fluid transfer element 20 provides an arrangement of hollow membrane tubes 62 having a first flow path 70 defined by the hollow membrane tubes 62; and a second flow path 72 that runs separately from the first flow path 70 and is defined by a gap 73 (best shown in Figures 13 to 14) defined between adjacent hollow membrane tubes 62. The second flow path 72 generally runs between an inlet region 74 and an outlet region 76.

[0096] When introduced into an application, for example, into a housing 22, the first flow path 70 is inserted along a portion of the housing intake flow path 36 (for example, for humidifying dry air) and forms part of the housing intake flow path 36, and the second flow path 72 is inserted along a portion of the housing exhaust and discharge flow path 42 (for example, for removing moisture from humid air) and forms part of the housing exhaust and discharge flow path 42. The inlet region 74 and outlet region 76 of the fluid transfer element 20 are in fluid communication with the humid inlet port 38 and the humid outlet port 40 within the housing 22, as shown in the figure.

[0097] To facilitate the second wetting channel 72, cartridges 52, 54, and 56 each have side walls 90, as best shown in Figure 9 (the side walls 90 are also indicated by reference numerals in Figure 3 to show their fitting into the cartridge opening 30 at the partition wall 28). As shown in Figure 9, the side walls 90 provide the cartridge with a preferably impermeable central section, thereby allowing a more wetting airflow to pass more or less along the entire length of the hollow membrane tube 62, and the side walls 90 provide a wetting inlet opening 92 adjacent to one end cap 58 and a wetting outlet opening 94 adjacent to the other end cap 60.

[0098] As shown in Figure 9, the wet inlet opening 92 can be provided by a single window (e.g., an annular gap between the side wall 90 and the end cap 58) that extends around the entire circumference of each cartridge. However, the side wall 90 may extend to the end cap 58 and be embedded within the end cap 58, and the wet inlet opening 92 may be provided by one or more windows formed within the side wall that do not extend around the entire circumference, for example, two window openings on opposite front / rear sides, or two window openings on opposite lateral sides, or four window openings, for example, one window on each of the four sides of the cartridge. Similarly, on the outlet side, as shown in Figure 9, the wet outlet opening 94 can be provided by a single window (e.g., an annular gap between the side wall 90 and the end cap 60) that extends around the entire circumference of each cartridge. However, the side wall 90 may extend to the end cap 60 and be embedded within the end cap 60, and the wet outlet opening 94 may be provided by one or more windows formed in the side wall that do not extend around the entire circumference, for example, two window openings may be provided on opposite front / rear sides, or two window openings may be provided on opposite lateral sides, or four window openings may be provided, for example, one window on each of the four sides of the cartridge.

[0099] As also illustrated, the arrangement of the hollow membrane tubes 62 includes tubes having different flow cross-sectional areas, arranged to provide different flow limiting characteristics. The arrangement of the hollow membrane tubes includes a first assembly 64 of hollow membrane tubes having a smaller average flow cross-sectional area than a second assembly 68 of hollow membrane tubes. And, as shown in some embodiments, optionally includes more assemblies, for example, a third assembly 66 of membrane tubes having an average flow cross-sectional area different from the average flow cross-sectional area of ​​the first or second assembly 68.

[0100] Different average flow cross-sectional areas can be easily obtained by grouping hollow membrane tubes 62 having different widths / diameters, such as having small diameter tubes 62A, large diameter tubes 62C, and optionally medium diameter tubes 62B, as illustrated; or alternatively, such assemblies and groupings can also be achieved by mixing different quantities of such hollow membrane tubes 62 of different widths / diameters (for example, one assembly may have a mixture of 20% large diameter tubes 62C and 80% small diameter tubes 62A, and the other assembly may have a mixture of 80% large diameter tubes 62C and 20% small diameter tubes 62A). In these types of hollow membrane tubes, it is assumed / estimated in the art that the tubes are typically round and therefore have an average diameter (or average width). Even if not perfectly cylindrical, such hollow membrane tubes 62 are considered to have a diameter (sometimes called width), as understood in the art.

[0101] For example, Figures 13 and 14 are illustrated to show the inner width / inner diameter and outer width / outer diameter dimensions IW and OW, respectively, for hollow membrane tube yarns 62. Typically, for various hollow membrane tubes 62 of different sizes (62A, 62B, 62C), the inner diameter IW of each individual hollow membrane tube 62 is less than 2 mm, preferably more typically 0.4 mm to 1.3 mm.

[0102] Typically, the wall thickness of each hollow membrane tube 62 is relatively thin, regardless of size, 0.2 mm or less, and in embodiments, typically 0.1 mm (e.g., wall thickness of 0.05 to 0.15 mm) for most tubes, but preferably the wall thickness range may be selected to be 0.15 mm to 1.5 mm. Such wall thickness can affect the gas interaction between the flow paths 70, 72, allowing for the residence time of water vapor within the threads of the hollow membrane tube 62 for movement between the passages. Thus, for example, if the wall thickness is 0.1 mm, the inner diameter / inner width IW is calculated to be 0.2 mm when the outer diameter / outer width OW is subtracted. Since the inner diameter / inner width IW determines the available cross-sectional area flow, it is referred to more frequently than the outer diameter / outer width OW in this specification.

[0103] The hollow membrane tubes 62 may be selected to have different flow cross-sectional areas provided by the small-diameter and large-diameter tubes, where the large-diameter tube 62C has an inner diameter / inner width IW that is at least 0.1 mm larger than that of the small-diameter tube 62A. Typically, the large-diameter tube 62C has an inner diameter / inner width IW that is at least 0.2 to 0.8 mm larger than that of the small-diameter tube 62A. If a medium-diameter tube 62B is used, the medium-diameter tube 62B may have an intermediate inner diameter / inner width IW size (preferably differing from the size of the small-diameter tube by only 0.1 to 0.4 mm and also differing from the size of the large-diameter tube by only 0.1 to 0.4 mm).

[0104] For example, in another embodiment, small-diameter tubes 62A having an inner diameter / inner width IW of 0.4 to 0.7 mm may be selected, while large-diameter tubes 62C may have an inner diameter / inner width IW of 0.7 to 1.3 mm, and in some examples even larger up to 1.7 mm. Additionally, interlayer tubes 62B can be used between the small-diameter and large-diameter tubes. Furthermore, while a uniform assembly of tubes of the same common size is shown for different assemblies, a mixture of different sizes may be optionally performed for different assemblies. In this regard, the assembly of hollow membrane tubes can be said to be the average cross-sectional area of ​​all large-diameter tubes and all small-diameter tubes in a given configuration.

[0105] By selectively using tubes of different sizes (either a uniformly sized assembly or an assembly with selectively different sizes), substantially different cross-sectional area flows can be generated, thereby producing different limiting and pressure drop characteristics at different locations. More typical tube sizes that can be used in this embodiment are shown in the table below.

[0106] [Table 1-1] [Table 1-2]

[0107] The table above shows the available flow area (4th column) through the hollow region of the tube's void, and the ability of interaction between different flow paths occurring within the tube's thread thickness (i.e., the thickness of the thread membrane) affects the efficiency of moisture transfer between the wet flow path 70 and the dry flow path 72. However, for embodiments, the wall thickness may be varied, for example, as shown in Table 2 below. Also, for different groupings of threads used in one embodiment, different threads may have different wall thicknesses. In any case, since the outer width / outer diameter OW correlates very closely with the inner width / inner diameter IW by the wall thickness, referring to the inner width / inner diameter IW is a useful parameter for considering both resistance / pressure drop along both the wet flow path 70 and the dry flow path 72.

[0108] [Table 2]

[0109] Due to these possibilities, and depending on which tubes are selected for the minimum or maximum inner diameter (IW), and as indicated by the flow area in the chart above, typically the first assembly 64 of hollow membrane tubes 62a has a first average flow cross-sectional area (shown in column 4, “Thread Tube Flow Cross-sectional Area,” in Table 1), which is typically 5% to 80% of the second average flow cross-sectional area of ​​the second assembly 68 of hollow membrane tubes 62c, and more typically 20% to 50% of the second average flow cross-sectional area of ​​the second assembly 68 of hollow membrane tubes 62c. Although the illustrated embodiments show an assembly of tubes with tubes of a common size, a mixture of tubes of different sizes can be used for the first assembly 64 with a smaller average flow cross-sectional area, and a mixture of tubes of different sizes can be used for the second assembly 68 with a larger average flow cross-sectional area, but still typically within these ranges with respect to flow cross-sectional area.

[0110] As described above and shown in Figures 3 to 9, the assemblies 64, 66, and 68 can be placed within cartridges 52, 54, and 56 arranged at different intervals, each cartridge having a tube of a common diameter / width as shown. Alternatively, other assemblies 64, 66, and 68, not shown, can be grouped together rather than separated by something like a partition, and placed, for example, into one or more of the cartridges 52, 54, and 56, within which additional cartridges can be created within one or more of the illustrated cartridges.

[0111] Preferably, as shown, the tubes 62A of the first assembly 64 are each of a first common size, the tubes 62B of the second assembly 66 are each of a second common size, and, if used, the tubes 62C of the third assembly 68 are each of a third common size.

[0112] The use of hollow membrane tubes 62 of different sizes can produce several advantages in different configurations, as shown in the embodiments of Figures 2 to 9, and in other embodiments such as Figures 10 to 12. This provides several different features, as described in the following paragraphs, which can be realized individually in one embodiment and / or in combination with other or more features in the other embodiment.

[0113] One feasible feature is that by mixing yarn sizes, it may be possible to increase the pressure drop in the shell (e.g., the second passage 42) and the yarn (e.g., the first passage 36), but such mixing and arrangement may lead to a method of optimizing yarn size to obtain a greater improvement in moisture transfer efficiency at a small pressure difference cost. The present application effectively considers that small diameter yarns, too, will be characterized by the pressure drop and fluid flow of the moist flow in embodiments where they are subjected to a larger flow or are arranged with a larger pressure difference due to the increased flow. In other words, small diameter yarns can be placed where a higher velocity is expected for the moist air flow (and / or where a higher pressure drop is possible), and preferably where a higher velocity is expected for the dry air flow (and / or where a higher pressure drop is possible).

[0114] Therefore, the feature is that the smaller assemblies 64 of hollow membrane tubes 62A (for example, having a smaller average flow cross-sectional area) are positioned to receive a greater pressure drop from either or both of the other assemblies 66, 68 of larger hollow membrane tubes 62B, 62C along the second flow path 72 (for example, the wet flow between the gaps 73 in Figures 13-14).

[0115] Another further feature is that the first assembly 60 of the smaller hollow membrane tubes 62A is positioned to receive a greater pressure drop from either or both of the other assemblies 66, 68 of the larger hollow membrane tubes 62B, 62C along the first flow path 70 (e.g., a dry flow through the tube that is to be humidified).

[0116] Another feature is that two or more of the assemblies 64, 66, and 68 of the hollow membrane tube 62 are arranged in a parallel fluid circuit along a second flow path 72 (e.g., gaps between threads), as shown in Figures 3 to 9 (see also Figures 13 to 14 showing gaps 73 for the second flow path 72). The parallel fluid circuit allows the fluid to alternatively flow alternately through one or the other of the assemblies 64, 66, and 68 through the gaps, but does not force it to flow sequentially through the gaps of different assemblies.

[0117] To further elaborate on the features of the parallel fluid arrangement described above, this feature can avoid the occurrence of a combination of pressure drop and restriction, as illustrated by the embodiments in Figures 3 to 9 (however, such a feature is not used in the illustrated embodiments in Figures 10 to 12). For example, if a humid airflow had to pass through the gaps between multiple assemblies in Figures 2 to 9, a cumulative restriction would occur, resulting in an even greater pressure drop and velocity reduction. This is avoided, allowing the designer more choices in selecting the grouping of threads and thread sizes for efficiency, flow velocity, and pressure difference (and can also affect energy input or energy availability for generating the fluid flow, etc.). Furthermore, two or more of the assemblies 64, 66, 68 of the hollow membrane tubes 62 are also arranged in a parallel fluid circuit along the first flow path 70 as shown in Figures 3 to 9, so that the fluid flow through the tubes is also in a parallel fluid circuit (for example, the incoming dry airflow can flow through only individual tubes and cannot flow through multiple tubes in series).

[0118] Another further feature illustrated in Figures 2 to 9 is that the element is provided by multiple (e.g., two or more) spaced-apart cartridges 52, 54, 56. Different cartridges 52, 54, 56 can each have different assemblies of membrane tubes 62 having different average flow cross-sectional areas, thus enabling different configurations to be achieved. For example, in the illustrated embodiment, the first assembly 64 of hollow membrane tubes 62A has a smaller average flow cross-sectional area than the second assembly 68 of hollow membrane tubes 62C, and optionally, one or more intermediate-sized assemblies 64 of hollow membrane tubes 62B can be used.

[0119] A feature of the arrangement structure is provided that allows different sets of membrane tubes to be placed in regions where higher flow and / or higher pressure differences are expected. For example, a first assembly 64 (e.g., smaller tubes 64A) can be placed closer to the inlet region 74 of a second channel 72 (e.g., for wet flow) than a second assembly 68 (e.g., larger tubes 62C).

[0120] Returning to the description and further consideration of the embodiments illustrated in Figures 2 to 9, in these embodiments, the housing 22 preferably has a rectangular box-shaped structure having six sides 80 to 85 defining the element cavity 26. In this embodiment, the dry inlet port 32 and the dry outlet port 34 are aligned along one common side 80 of the six sides. The wet inlet port 38 and the wet outlet port 40 may also be aligned along one common side 80, which may be the same side aligned with the dry inlet port 32 and the dry outlet port 34. This provides all connections in one location, however, in another embodiment, the arrangement of ports may be along a different wall and / or divided and arranged on different walls.

[0121] Further embodiments are shown in Figures 10 to 12 to demonstrate that arrangements of threads of different sizes can be used in other arrangements, and that this can achieve one or more of the above features (other than the feature of parallel circuits for a second wet passage).

[0122] Referring to Figures 10 to 12, a further embodiment shows a fluid transfer element 110 which includes an arrangement structure of a ring-shaped hollow membrane tube 112 surrounding a central open cavity 114. A pair of end caps (e.g., an open end cap 116 and a closed end cap 118) are located at opposite ends of the arrangement structure of the hollow membrane tube 112, and at least one of the end caps 116 has an opening 120 that communicates fluid into the central open cavity 114.

[0123] Furthermore, a first flow path 122 (for example, for a flow of dry air to be humidified, as shown in Figure 1) is defined by the hollow membrane tube 112; a second flow path 124 runs separately from the first flow path 122 and is defined by gaps defined between adjacent members of the hollow membrane tube 112 (in other words, surrounding the outside / periphery of the tube). In this embodiment, the second flow path 124 extends radially between the central open cavity 114 and the outer perimeter 126 surrounding the arrangement structure (e.g., an outer perimeter ring-shaped chamber). Furthermore, as illustrated, this arrangement structure of the hollow membrane tube 112 has tubes 112A and 112B having different flow cross-sectional areas.

[0124] Furthermore, in this embodiment, the arrangement structure of the hollow membrane tubes 112 includes a first assembly 128 of small-diameter hollow membrane tubes 112A and a second assembly 130 of large-diameter hollow membrane tubes 112B. Thus, this embodiment achieves the characteristic that the first assembly 128 of the hollow membrane tubes 112 has a smaller average flow cross-sectional area than the second assembly 130 of the hollow membrane tubes 112.

[0125] Furthermore, this embodiment may have similar features, such as a third assembly 132 of the small-diameter tube 112A and / or a fourth assembly 134 of the large-diameter tube 112B.

[0126] In the fluid transfer element 110, the arrangement structure of the hollow membrane tube 112 has an innermost annular region 136 of the hollow membrane tube, which has a different average flow cross-sectional area from another annular region 138 of the hollow membrane tube. Multiple annular regions may be provided, including an additional intermediate annular region 140 and an outermost region 140. How these are arranged in terms of size for tube selection may depend on whether the wet fluid flow is radially outward or radially inward.

[0127] In the illustrated embodiment, assuming flow radially outward (for example, from cavity 114 to outer chamber 126), the innermost annular region 136 has a first average flow cross-sectional area of ​​the hollow membrane tube 112 that is larger than the second average flow cross-sectional area of ​​the hollow membrane tube 112 of another region 138 surrounding it.

[0128] In this arrangement, the flow area directly adjacent to the cavity 114 is limited, and there is a larger gap at this point, which is advantageous as it promotes flow toward the surrounding region 138, where the moisture transport efficiency is increased by the larger yarn surface area.

[0129] As illustrated, additional regions may be layered to limit the restricting effect and provide a larger area that allows for the discharge of wet flow. Thus, there is a third intermediate annular region 140 of the hollow membrane tube 112, having a third annular region radially outward from the second annular region 138. As illustrated, the third annular region 140 has a third average flow cross-sectional area of ​​the hollow membrane tube that is larger than the second average flow cross-sectional area of ​​the second annular region 138.

[0130] This design also aims to achieve more efficient transport, in which case many gaps occur in the outermost region, thereby creating a fourth annular region 142 at the outermost edge of the hollow membrane tube 112. The fourth annular region 142, radially outside the third annular region 140, has a fourth annular region having a fourth average flow cross-sectional area of ​​the hollow membrane tube that is smaller than the third average flow cross-sectional area of ​​the third annular region 140.

[0131] Optionally, a tubular support cage 144 is located inside the central cavity 114, and optionally, an outer tubular support cage 146 surrounds the hollow membrane tube 112.

[0132] The parameters for the thread, size, and material type for the end cap may be the same as those described for the first embodiment in Figures 2 to 9.

[0133] The fluid transfer element 110 can be incorporated into an assembly 148 which can be inserted as a humidifier as shown in Figure 1. The assembly 148 further includes a housing 150 which defines an element cavity 152 that houses the fluid transfer element 110.

[0134] The housing 150 further has a first pair of fluid ports 154, 156, which are provided with a first flow path 122 arranged to flow between them. For example, in this embodiment, port 154 is an inlet for dry air and port 156 is an outlet for dry air (this air is now at least partially humidified by the flow). The housing further has a second pair of fluid ports 158, 160, which are provided with a second flow path 124 arranged to flow between them. For example, in this embodiment, port 158 ​​is an inlet for moist exhaust gas and port 160 is an outlet for moist air to be discharged into the external environment.

[0135] The wet inlet port 158 ​​communicates with the inlet region 162 of the fluid transfer element 110, and the wet outlet port 160 communicates with the outlet region 164 of the fluid transfer element 110. In this embodiment, the inlet region 162 corresponds to the central open cavity 114. However, as described, depending on whether the design is for radial inward or radial outward orientation, the inlet region 163 may be an annular chamber 126 surrounding the outer periphery of the outermost annular region 142 of the hollow membrane tube 112, or instead may be provided by the central open cavity 114 as shown.

[0136] All references cited herein, including publications, patent applications, and patents, are incorporated herein by reference to the same extent that each reference is incorporated by reference individually and specifically, and that the whole is incorporated herein by reference.

[0137] In the context describing the present invention (particularly in the context of the following claims), the use of the terms “a,” “an,” and “the,” and similar reference subjects, should be interpreted as encompassing both singular and plural, unless otherwise indicated herein or unless clearly inconsistent with the context. The terms “comprising,” “having,” “including,” and “containing” should be interpreted as open-ended terms (i.e., “including, but not limited to”), unless otherwise specified herein. The enumeration of value ranges herein is intended, unless otherwise indicated herein, simply as a simple way to individually refer to each distinct value contained within that range, and each distinct value is incorporated herein as if it were individually enumerated herein. All methods described herein may be performed in any suitable order, unless otherwise indicated herein or unless clearly inconsistent with the context. The use of any examples or illustrative words provided herein (e.g., "etc.") is intended solely to better illustrate the invention and, unless otherwise noted, does not limit the scope of the invention. No term used herein should be construed as indicating that any unclaimed element is essential for the practice of the invention.

[0138] Terms such as “first,” “second,” and “third” are used solely for distinction to differentiate or identify different members or members of a group, and therefore, for example, these terms do not represent any series restriction, any arrangement restriction, or any numerical restriction. For example, if one embodiment describes and explains a first set, a second set, and a third set, then references in the claims, such as the claimed first set and the claimed second set, are satisfied by the described first set and the described second set, the described first set and the described third set, and / or the described second set and the described third set.

[0139] Preferred embodiments of the present invention are described herein, including the best modes known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those skilled in the art by reading the preceding description. The inventors expect that those skilled in the art will appropriately adopt such variations, and they intend to carry out the invention in ways other than those specifically described herein. Accordingly, the invention includes all variations and equivalents of the subject matter described in the claims appended herein, as permitted by applicable law. Furthermore, any combination of the above elements in all possible variations thereof is incorporated herein unless otherwise specifically specified herein and unless it is clearly inconsistent with the context.

Claims

1. A fluid transfer element, It has an arrangement structure of hollow membrane tubes, and the arrangement structure is (a) A first flow path defined by the hollow membrane tube; (b) A second channel that runs separately from the first channel and through a gap defined between adjacent members of the hollow membrane tube, the second channel running between an inlet region and an outlet region; It has, The arrangement structure of the hollow membrane tubes includes tubes having different flow cross-sectional areas arranged to provide different flow limiting characteristics, and includes a first assembly of the hollow membrane tubes, the first assembly having a smaller average flow cross-sectional area than a second assembly of the hollow membrane tubes; The first assembly of the hollow membrane tubes is positioned along the second flow path such that it receives a greater pressure drop than the second assembly of the hollow membrane tubes. Fluid transfer element.

2. The fluid transfer element according to claim 1, wherein the first assembly of the hollow membrane tubes is also arranged along the first flow path to receive a greater pressure drop than the second assembly of the hollow membrane tubes.

3. The fluid transfer element according to claim 1, further comprising a first cap and a second cap densely embedded inside the hollow membrane tube, wherein the intermediate portion of the hollow membrane tube between the first end cap and the second end cap is exposed to the second flow path.

4. The fluid transfer element according to claim 1, wherein the first assembly of the hollow membrane tubes has a first average flow cross-sectional area, the first average flow cross-sectional area being 10% to 80% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes, more preferably 20% to 50% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes.

5. The fluid transfer element according to claim 1, wherein the hollow membrane tube has an inner diameter / inner width defined as less than 2 mm, preferably 0.4 mm to 1.3 mm, and the inner diameter / inner width of the second assembly of the hollow membrane tube is at least 0.1 mm, preferably 0.2 mm to 0.8 mm larger than the inner diameter / inner width of the first assembly of the hollow membrane tube.

6. The fluid transfer element according to claim 1, wherein the hollow membrane tubes having different flow cross-sectional areas include at least three hollow membrane tubes of different sizes.

7. An assembly comprising a fluid transfer element according to claim 1, wherein the assembly further comprises a housing defining an element cavity for housing the fluid transfer element, the housing further comprises A first pair of fluid ports comprising a first inlet and a first outlet, and a first flow path arranged to flow between the first pair of fluid ports; A second pair of fluid ports comprising a second inlet and a second outlet, and a second flow path arranged to flow between the second pair of fluid ports, wherein the second inlet communicates with an inlet region and the second outlet communicates with an outlet region. An assembly that has

8. The assembly according to claim 7, wherein the housing comprises a housing body and a removable lid, the lid being removable to allow replacement of a fluid transfer element.

9. The assembly according to claim 8, wherein the fluid transfer element is divided into separate cartridges, each cartridge comprising a first cartridge and a second cartridge in a spaced-out relationship, each cartridge having a spaced-out first cap and a second cap, each having a tightly engaged assembly of hollow membrane tubes within each cap, the first cartridge having a first assembly of the hollow membrane tubes, and the second cartridge having a second assembly of the hollow membrane tubes.

10. The assembly according to claim 7, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the first inlet and the first outlet are aligned along a single common face among the six faces.

11. The assembly according to claim 7, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the second inlet and the second outlet are aligned along a single common face among the six faces.

12. The assembly according to claim 7, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and each of the first inlet, first outlet, second inlet, and second outlet is aligned with a single common face among the six faces.

13. The fluid transfer element according to claim 1, wherein the arrangement structure of the hollow membrane tube surrounds a central open cavity and further has a pair of end caps at opposing ends of the arrangement structure, one of the end caps having an opening communicating with the central open cavity, the second flow path extends radially between the central open cavity and the outer perimeter surrounding the arrangement structure, and the arrangement structure of the hollow membrane has a set of hollow membrane tubes having different flow cross-sectional areas including at least a first annular region and a second annular region.

14. The fluid transfer element according to claim 13, wherein the first annular region is radially inward of the second annular region and has the hollow membrane tube of the first annular region having a larger average flow cross-sectional area than the hollow membrane tube of the second annular region.

15. The fluid transfer element according to claim 14, further comprising a third annular region of the hollow membrane tube radially outward of the second annular region, wherein the third annular region has a hollow membrane tube of the third annular region having a larger average flow cross-sectional area than the hollow membrane tube of the second annular region.

16. The fluid transfer element according to claim 1, wherein the hollow membrane tubes of the first assembly are each of a first common size, and the hollow membrane tubes of the second assembly are each of a second common size.

17. A fluid transfer element, It has an arrangement structure of hollow membrane tubes, and the arrangement structure is (a) A first flow path defined by the hollow membrane tube; (b) A second channel that runs separately from the first channel and through a gap defined between adjacent members of the hollow membrane tube, the second channel running between an inlet region and an outlet region; It has, The arrangement structure of the hollow membrane tubes comprises tubes having different flow cross-sectional areas; The fluid transfer element is provided by a plurality of cartridges, each including a first cartridge and a second cartridge that are spaced apart from each other, each having a spaced-apart first cap and a second cap, each having a tightly engaged assembly of the hollow membrane tubes within the cap, the first cartridge having a first assembly of the hollow membrane tubes, the second cartridge having a second assembly of the hollow membrane tubes, and the first assembly of the hollow membrane tubes having a smaller average flow cross-sectional area than the second assembly of the hollow membrane tubes. Fluid transfer element.

18. The fluid transfer element according to claim 17, wherein all of the hollow membrane tubes of the first cartridge are of the same size, and / or all of the hollow membrane tubes of the second cartridge are of the same size.

19. The fluid transfer element according to claim 17, wherein the first assembly of the hollow membrane tubes is also arranged along the first flow path to receive a greater pressure drop than the second assembly of the hollow membrane tubes.

20. The fluid transfer element according to claim 17, further comprising a first cap and a second cap densely embedded inside the hollow membrane tube, wherein the intermediate portion of the hollow membrane tube between the first end cap and the second end cap is exposed to the second flow path.

21. The fluid transfer element according to claim 17, wherein each cartridge has a side wall with a window near each end cap, the window communicating through the window to the second flow path.

22. The fluid transfer element according to claim 17, wherein the first assembly of the hollow membrane tubes has a first average flow cross-sectional area, the first average flow cross-sectional area being 10% to 80% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes, more preferably 20% to 50% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes.

23. The fluid transfer element according to claim 17, wherein the hollow membrane tube has an inner diameter / inner width defined as less than 2 mm, preferably 0.4 mm to 1.3 mm, and the inner diameter / inner width of the second assembly of the hollow membrane tube is at least 0.1 mm, preferably 0.2 mm to 0.8 mm larger than the inner diameter / inner width of the first assembly of the hollow membrane tube.

24. The fluid transfer element according to claim 17, wherein the hollow membrane tubes having different flow cross-sectional areas include at least three hollow membrane tubes of different sizes.

25. The fluid transfer element according to claim 17, wherein the hollow membrane tubes of the first assembly are each of a first common size, and the hollow membrane tubes of the second assembly are each of a second common size.

26. The fluid transfer element according to claim 17, wherein the plurality of cartridges further include a third cartridge spaced apart from the first cartridge and the second cartridge, the second cartridge being inserted between the first cartridge and the third cartridge, and the third cartridge having a third assembly of the hollow membrane tubes, the third assembly of the hollow membrane tubes having a larger average flow cross-sectional area than the first and second assemblies of the hollow membrane tubes.

27. An assembly comprising a fluid transfer element according to claim 1, wherein the assembly further comprises a housing defining an element cavity for housing the fluid transfer element, the housing further comprises A first pair of fluid ports comprising a first inlet and a first outlet, and a first flow path arranged to flow between the first pair of fluid ports; A second pair of fluid ports comprising a second inlet and a second outlet, and a second flow path arranged to flow between the second pair of fluid ports, wherein the second inlet communicates with an inlet region and the second outlet communicates with an outlet region. An assembly that has

28. The assembly according to claim 27, wherein the housing comprises a housing body and a removable lid, the lid being removable to allow replacement of the cartridge of the fluid transfer element.

29. The assembly according to claim 27, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the first inlet and the first outlet are aligned along a single common face among the six faces.

30. The assembly according to claim 27, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the second inlet and the second outlet are aligned along a single common face among the six faces.

31. A fluid transfer element, It has an arrangement structure of hollow membrane tubes, and the arrangement structure is (a) A first flow path defined by the hollow membrane tube; (b) A second channel that runs separately from the first channel and through a gap defined between adjacent members of the hollow membrane tube, the second channel running between an inlet region and an outlet region; It has, The arrangement structure of the hollow membrane tubes is a tube having different flow cross-sectional areas; and The system comprises a first assembly of hollow membrane tubes and a second assembly of hollow membrane tubes, wherein the first assembly of hollow membrane tubes has a smaller average flow cross-sectional area than the second assembly of hollow membrane tubes, and the first and second assemblies of hollow membrane tubes are arranged in a fluid circuit parallel to the second flow path. Fluid transfer element.

32. The fluid transfer element according to claim 31, further comprising at least one partition wall between the first assembly and the second assembly.

33. The fluid transfer element according to claim 31, wherein the fluid transfer element is provided by a plurality of cartridges including a first cartridge and a second cartridge, each cartridge having a spaced-apart first cap and a second cap, each cap having a close-fitted assembly of the hollow membrane tubes, the first cartridge having the first assembly of the hollow membrane tubes, and the second cartridge having the second assembly of the hollow membrane tubes.

34. The fluid transfer element according to claim 31, wherein all of the hollow membrane tubes of the first assembly are of the same size, and / or all of the hollow membrane tubes of the second assembly are of the same size.

35. The fluid transfer element according to claim 31, wherein the first assembly of the hollow membrane tubes is also arranged along the first flow path to receive a greater pressure drop than the second assembly of the hollow membrane tubes.

36. The fluid transfer element according to claim 31, wherein the second assembly of the hollow membrane tubes is arranged along the second flow path so as to be further downstream relative to the first assembly of the hollow membrane tubes.

37. The fluid transfer element according to claim 31, further comprising a first cap and a second cap densely embedded inside the hollow membrane tube, wherein the intermediate portion of the hollow membrane tube between the first end cap and the second end cap is exposed to the second flow path.

38. The fluid transfer element according to claim 31, wherein the first assembly of the hollow membrane tubes has a first average flow cross-sectional area, the first average flow cross-sectional area being 10% to 80% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes, more preferably 20% to 50% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes.

39. The fluid transfer element according to claim 31, wherein the hollow membrane tube has an inner diameter / inner width defined as less than 2 mm, preferably 0.4 mm to 1.3 mm, and the inner diameter / inner width of the second assembly of the hollow membrane tube is at least 0.1 mm, preferably 0.2 mm to 0.8 mm larger than the inner diameter / inner width of the first assembly of the hollow membrane tube.

40. The fluid transfer element according to claim 31, wherein the hollow membrane tubes having different flow cross-sectional areas include at least three hollow membrane tubes of different sizes.

41. The fluid transfer element according to claim 31, further comprising a third assembly of hollow membrane tubes, wherein the third assembly of hollow membrane tubes has a larger average flow cross-sectional area than the first and second assemblies of hollow membrane tubes.

42. The fluid transfer element according to claim 41, wherein the third assembly is arranged in a parallel fluid circuit including the first assembly and the second assembly.

43. An assembly comprising a fluid transfer element according to claim 31, wherein the assembly further comprises a housing defining an element cavity for housing the fluid transfer element, the housing further comprises A first pair of fluid ports comprising a first inlet and a first outlet, and a first flow path arranged to flow between the first pair of fluid ports; A second pair of fluid ports comprising a second inlet and a second outlet, and a second flow path arranged to flow between the second pair of fluid ports, wherein the second inlet communicates with an inlet region and the second outlet communicates with an outlet region. An assembly that has

44. The assembly according to claim 43, wherein the housing comprises a housing body and a removable lid, the lid being removable to allow replacement of the first and second assemblies of the fluid transfer element.

45. The assembly according to claim 44, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the first inlet and the first outlet are aligned along a single common face among the six faces.

46. The assembly according to claim 44, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the second inlet and the second outlet are aligned along a single common face among the six faces.

47. A fluid transfer element, It has an arrangement structure of hollow membrane tubes, and the arrangement structure is (a) A first flow path defined by the hollow membrane tube; (b) A second channel that runs separately from the first channel and through a gap defined between adjacent members of the hollow membrane tube, the second channel running from an inlet region to an outlet region; It has, The arrangement structure of the hollow membrane tubes comprises tubes having different flow cross-sectional areas, including a first assembly of the hollow membrane tubes and a second assembly of the hollow membrane tubes, wherein the first assembly of the hollow membrane tubes has a smaller average flow cross-sectional area than the second assembly of the hollow membrane tubes, and the first assembly of the hollow membrane tubes is located closer to the inlet region of the second flow path than the second assembly. Fluid transfer element.

48. The fluid transfer element according to claim 47, wherein the first assembly of the hollow membrane tubes is arranged along the first flow path to receive a greater pressure drop than the second assembly of the hollow membrane tubes.

49. The fluid transfer element according to claim 47, further comprising a first cap and a second cap densely embedded inside the hollow membrane tube, wherein the intermediate portion of the hollow membrane tube between the first end cap and the second end cap is exposed to the second flow path.

50. The fluid transfer element according to claim 47, wherein the first assembly of the hollow membrane tubes has a first average flow cross-sectional area, the first average flow cross-sectional area being 10% to 80% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes, more preferably 20% to 50% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes.

51. The fluid transfer element according to claim 47, wherein the hollow membrane tube has an inner diameter / inner width defined as less than 2 mm, preferably 0.4 mm to 1.3 mm, and the inner diameter / inner width of the second assembly of the hollow membrane tube is at least 0.1 mm, preferably 0.2 mm to 0.8 mm larger than the inner diameter / inner width of the first assembly of the hollow membrane tube.

52. The fluid transfer element according to claim 47, wherein the hollow membrane tubes having different flow cross-sectional areas comprise at least three hollow membrane tubes of different sizes.

53. An assembly comprising a fluid transfer element according to claim 47, wherein the assembly further comprises a housing defining an element cavity for housing the fluid transfer element, the housing further comprises A first pair of fluid ports comprising a first inlet and a first outlet, and a first flow path arranged to flow between the first pair of fluid ports; A second pair of fluid ports comprising a second inlet and a second outlet, and a second flow path arranged to flow between the second pair of fluid ports, wherein the second inlet communicates with an inlet region and the second outlet communicates with an outlet region. An assembly that has

54. The assembly according to claim 53, wherein the housing comprises a housing body and a removable lid, the lid being removable to allow replacement of a fluid transfer element.

55. The assembly according to claim 54, wherein the fluid transfer element is divided into separate cartridges, each cartridge comprising a first cartridge and a second cartridge in a spaced-out relationship, each cartridge having a spaced-out first cap and a second cap, each having a close-fitting assembly of the hollow membrane tubes within each cap, the first cartridge having a first assembly of the hollow membrane tubes, and the second cartridge having a second assembly of the hollow membrane tubes.

56. The assembly according to claim 53, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the first inlet and the first outlet are aligned along a single common face among the six faces.

57. The assembly according to claim 53, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and the second inlet and the second outlet are aligned along a single common face among the six faces.

58. The assembly according to claim 53, wherein the housing has a rectangular box-shaped structure having six faces defining the element cavity, and each of the first inlet, first outlet, second inlet, and second outlet is aligned with a single common face among the six faces.

59. The fluid transfer element according to claim 47, wherein the arrangement structure of the hollow membrane tube surrounds a central open cavity and further has a pair of end caps at opposing ends of the arrangement structure, one of the end caps having an opening communicating with the central open cavity, the second flow path extends radially between the central open cavity and the outer perimeter surrounding the arrangement structure, and the arrangement structure of the hollow membrane has a tube having different flow cross-sectional areas including at least a first annular region and a second annular region.

60. The fluid transfer element according to claim 59, wherein the first annular region is radially inward of the second annular region and has the hollow membrane tube of the first annular region having a larger average flow cross-sectional area than the hollow membrane tube of the second annular region.

61. The fluid transfer element according to claim 60, further comprising a third annular region of the hollow membrane tube radially outward of the second annular region, wherein the third annular region has a hollow membrane tube of the third annular region having a larger average flow cross-sectional area than the hollow membrane tube of the second annular region.

62. An assembly comprising a fluid transfer element according to claim 60, wherein the assembly further comprises a housing defining an element cavity for housing the fluid transfer element, the housing further comprises A first pair of fluid ports comprising a first inlet and a first outlet, and a first flow path arranged to flow between the first pair of fluid ports; A second pair of fluid ports comprising a second inlet and a second outlet, and comprising a second flow path arranged to flow between the second pair of fluid ports, wherein the second inlet communicates with an inlet region and the second outlet communicates with an outlet region, and the inlet region is an annular chamber surrounding the outer periphery of the outermost annular region of the hollow membrane tube, or provided by a central open cavity. An assembly that has

63. A fluid transfer element, The arrangement of hollow membrane tubes in a ring structure surrounding the central open cavity, A pair of end caps at opposite ends of the arrangement structure, one of which has an opening that communicates with the central open cavity, A first flow path defined by the hollow membrane tube; A second flow path, separate from the first flow path and defined by a gap defined between adjacent members of the hollow membrane tube, the second flow path includes a second flow path that runs radially between the central open cavity and the outer perimeter surrounding the arrangement structure; It has, The arrangement structure of the hollow membrane tubes has tubes having different flow cross-sectional areas. Fluid transfer element.

64. The fluid transfer element according to claim 63, wherein the arrangement structure of the hollow membrane tubes includes a first assembly of the hollow membrane tubes and a second assembly of the hollow membrane tubes, the first assembly of the hollow membrane tubes having a smaller average flow cross-sectional area than the second assembly of the hollow membrane tubes.

65. The fluid transfer element according to claim 63, wherein the arrangement structure of the hollow membrane tube has a first annular region of the hollow membrane tube, and the first annular region has a different average flow cross-sectional area from that of the second annular region of the hollow membrane tube.

66. The fluid transfer element according to claim 65, wherein the first annular region is radially inward of the second annular region, and the first annular region has a first average flow cross-sectional area of ​​the hollow membrane tube that is larger than the second average flow cross-sectional area of ​​the hollow membrane tube of the second annular region.

67. The fluid transfer element according to claim 66, further comprising a third annular region of the hollow membrane tube, wherein the third annular region is radially outward of the second annular region, and the third annular region has a third average flow cross-sectional area of ​​the hollow membrane tube that is larger than the second average flow cross-sectional area.

68. The fluid transfer element according to claim 67, further comprising a fourth annular region of the hollow membrane tube, wherein the fourth annular region is radially outward of the third annular region and the fourth annular region has a fourth average flow cross-sectional area of ​​the hollow membrane tube that is smaller than the average flow cross-sectional area of ​​the third.

69. The fluid transfer element according to claim 65, wherein the first annular region provides the innermost region directly surrounding the central cavity, and optionally a tubular support cage is provided within the central cavity.

70. The fluid transfer element according to claim 63, wherein the first assembly of the hollow membrane tubes has a first average flow cross-sectional area, the first average flow cross-sectional area being 10% to 80% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes, more preferably 20% to 50% of the second average flow cross-sectional area of ​​the second assembly of the hollow membrane tubes.

71. The fluid transfer element according to claim 63, wherein the hollow membrane tube has an inner diameter / inner width defined as less than 2 mm, preferably 0.4 mm to 1.3 mm, and the inner diameter / inner width of the second assembly of the hollow membrane tube is at least 0.1 mm, preferably 0.2 mm to 0.8 mm larger than the inner diameter / inner width of the first assembly of the hollow membrane tube.

72. The fluid transfer element according to claim 63, wherein the hollow membrane tubes having different flow cross-sectional areas include at least three hollow membrane tubes of different sizes.

73. An assembly comprising a fluid transfer element according to claim 63, wherein the assembly further comprises a housing defining an element cavity for housing the fluid transfer element, the housing further comprises A first pair of fluid ports comprising a first inlet and a first outlet, and a first flow path arranged to flow between the first pair of fluid ports; A second pair of fluid ports comprising a second inlet and a second outlet, and comprising a second flow path arranged to flow between the second pair of fluid ports, wherein the second inlet communicates with the inlet region of the fluid transfer element, and the second outlet communicates with the outlet region of the fluid transfer element, and the inlet region is an annular chamber surrounding the outer periphery of the outermost annular region of the hollow membrane tube, or provided by the central open cavity. An assembly that has

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