air humidifier

Abstract

To provide an air humidifier that humidifies a relatively dry intake air flow by using a relatively humid exhaust air flow. [Solution] The humidifying effect of the air humidifier (1) can be improved by the air humidifier (1) having at least one orifice (14), which is arranged outside the membrane block (10) within the housing (4) so ​​that it can be flowed into by the air flow (15) formed by the intake air flow (2) or the exhaust air flow, and each orifice (14) is arranged and / or configured within the intake air path (12) or the exhaust air path so that the orifice causes uniform flow through the membrane block (10).

Description

[Technical Field]

[0001] The present invention relates to an air humidifier for humidifying a relatively dry intake air flow by means of a relatively humid exhaust air flow according to the preamble of claim 1 .

[0002] German Patent Application Publication No. 102020212596 discloses an air humidifier according to the general concept, which includes a housing and a membrane block arranged therein. The housing has four connections forming an inlet for supplying an inlet air flow, an outlet for discharging the inlet air flow, an outlet for supplying an exhaust air flow, and an outlet for discharging the exhaust air flow. The membrane block is impermeable to air but permeable to water vapor and includes membranes that form inlet air channels through which the inlet air flow can flow and outlet channels through which the exhaust air flow can flow. The inlet air channels and outlet channels are separated from each other within the membrane block by the membranes, such that the inlet air remains in the inlet air flow and the exhaust air remains in the exhaust air flow, while moisture in the form of water vapor penetrates the membranes from the exhaust air to the inlet air. The membranes here may be configured as flat membranes and arranged in stacked form in a membrane block, as is known from DE 10 2020 212 596. Alternatively, the membranes may be configured as hollow fiber membranes and arranged in bundles in a membrane block, as in DE 10 2015 224 202.

[0003] This type of air humidifier can be used particularly in fuel cell systems, where the relatively dry inlet air stream is formed by fresh air supplied to the cathode side of the fuel cell stack, and the relatively humid exhaust air stream is formed by the exhaust air from the cathode side of the fuel cell stack.

[0004] To achieve the lowest possible flow resistance, the membrane block is constructed relatively large, so that the side of the membrane block facing one of the connections has a significantly larger area than the cross-section of the connection facing that side of the membrane block. This also applies to the inlet side of the membrane block on the intake side, whose area is larger than the cross-sectional area of ​​the intake air inlet through which flow can be made. The same applies to the outlet side of the membrane block on the intake side, whose area is larger than the cross-sectional area of ​​the intake air outlet through which flow can be made. This also applies to the inlet side of the membrane block on the exhaust side, whose area is larger than the cross-sectional area of ​​the exhaust air inlet through which flow can be made. This relationship also applies to the outlet side of the membrane block on the exhaust side, whose area is significantly larger than the cross-sectional area of ​​the exhaust air outlet through which flow can be made. Therefore, due to the alignment and positioning of the connections in the housing, only partial areas of the membrane block are present in the outlet area of ​​the intake air inlet or exhaust air inlet, as well as in the inlet area of ​​the intake air outlet or exhaust air outlet. This inevitably leads to uneven flow through the membrane block in the intake air path and the exhaust air path. As a result, the humidifying performance of the air humidifier or the moisture transfer rate of the air humidifier is not optimally utilized, especially in areas of the membrane block that are relatively far from the respective connection, which are relatively poorly penetrated by the intake air flow or the exhaust air flow.

[0005] The present invention addresses the problem of providing an improved embodiment for an air humidifier as described above, which embodiment is characterized in particular by an increased humidifying performance or moisture transfer rate.

[0006] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0007] The present invention is based on the general idea of ​​arranging at least one orifice in the housing upstream or downstream of the membrane block in the intake or exhaust air flow to equalize the flow through the membrane block by the intake or exhaust air flow. The flow through the membrane block is equalized in this case by, on the one hand, positioning the orifice appropriately on the inlet or outlet side of the membrane block, and, on the other hand, by a correspondingly effective equalizing design of the orifice. For example, by using an orifice, the section of the membrane block directly facing the connection can be provided with increased flow resistance, so that the air flow generated by the intake or exhaust air flow has to be forced to deflect and thus reach other areas of the membrane block. This deflection or deflection of the air flow leads to an equalization of the flow through the membrane block.

[0008] In the context of this specification, "configuration" is equivalent to "design" and / or "arrangement," and the phrase "configured so" is synonymous with the phrases "designed so" and / or "arranged so."

[0009] In particular, the invention proposes that the air humidifier has at least one orifice, which is arranged in the housing outside the membrane block so that it can be filled by the air flow formed by the intake air flow or the exhaust air flow, and in this case the orifice is arranged and / or configured in particular in the intake air path or the exhaust air path so that the orifice causes a uniform flow through the membrane block.

[0010] According to an advantageous embodiment, each orifice can be arranged in the housing between the membrane block and one of the connections, so that the orifice faces the connection, particularly directly, i.e., via a direct or shortest path. This results in the projection of the through-flow cross section of the connection striking the orifice in the direction of the membrane block, parallel to the main direction of the air flow at the connection. In particular, the orifice can be arranged centered in the housing relative to the connection, so that the projection strikes the orifice centered. Thus, if the orifice in the membrane block is arranged on the inlet side of the membrane block, it mainly covers the inlet area from the respective connection. If the orifice in the membrane block is arranged on the outlet side, it covers the area directly connected to the respective connection of the membrane block.

[0011] Depending on the preferred embodiment, the orifice may be arranged in the housing in such a way that it can be circulated on its edge by the air flow, in other words, the orifice allows the deflection of the air flow up to the annular edge of the orifice and there allows circulation on the edge side of the orifice, so that the air flow also reaches areas of the membrane block that are relatively far from the central area of ​​the orifice.

[0012] An embodiment in which the orifice is configured to be pierceable by the air flow is advantageous. For this purpose, the orifice can be made of a porous material or have a honeycomb structure, a lattice structure, or a mesh structure. Similarly, the orifice can be configured as a perforated plate. Due to the pierceable orifice, the air flow can also pass through to the area of ​​the membrane block covered by the orifice.

[0013] According to an advantageous embodiment, the orifice may be configured such that the resistance to flow through the orifice is greater in the central region through which the orifice can pass than in the edge region through which the orifice can pass, by this means forcing the air flow away from the central region and towards the edge region, thereby helping to make the flow through the membrane block uniform.

[0014] According to an advantageous embodiment, the orifice can have a plurality of through-openings through which the air flow can pass, the through-openings formed in the central region having a smaller through-opening cross section than the through-openings formed in the edge regions, so that the orifice has a greater through-flow resistance in the central region than in the edge regions.

[0015] In an alternative embodiment, the orifice can have a plurality of through-openings through which the air flow can pass, the through-openings extending from the central region to the edge region, with the through-openings in the central region having a smaller through-opening width than those in the edge region, in other words, the through-openings diverging from the inside to the outside or converging from the outside to the inside. This measure also results in the orifice having a greater through-opening resistance in the central region than in the edge region.

[0016] According to a particularly advantageous embodiment, a grid may be arranged on the inlet or outlet side of each orifice, which may be configured to generate turbulence, through which the air flow can pass, and in which the grid structure generates turbulence in the air flow, which promotes the uniformity of the air flow.

[0017] The grid can completely cover the orifice. The orifice here can have an annular edge. The grid can either end flush with this edge of the orifice or protrude beyond the edge of the orifice. In particular, the grid can extend to the housing, thereby covering a circumferential or annular gap between the orifice and the housing, through which the orifice can flow on the edge side.

[0018] In contrast, in another embodiment, a grid for generating turbulence is arranged or formed in each through-hole, and it can be assumed that the grid completely fills the cross-section of the respective through-hole. In this embodiment, the grid or grid structure is integrated into the orifice and is only effective in the area of ​​the through-hole. For example, it is conceivable to use the grid as an insert for an injection mold for manufacturing an orifice made of plastic, whereby the grid fills the cross-section of the through-hole within the through-hole and is, at the same time, embedded in the material of the orifice.

[0019] In another embodiment, such an orifice may be located in the intake air stream upstream or downstream of the membrane block in the housing. Additionally or alternatively, such an orifice may be located in the exhaust air stream upstream or downstream of the membrane block in the housing. This allows the air humidifier to have exactly one orifice in the intake air stream or exactly one orifice in the exhaust air stream. Alternatively, the air humidifier may have exactly two or more orifices, specifically, at least one orifice in the intake air stream and at least one orifice in the exhaust air stream. For the orifice in the intake air stream, locating the orifice upstream of the membrane block is preferred because an improved moisture transfer rate is expected there, based on the resulting lower air pressure within the membrane block. For the orifice in the exhaust air stream, locating the orifice downstream of the membrane block is preferred because an improved moisture transfer rate is expected there, based on the resulting higher air pressure within the membrane block.

[0020] In a particularly advantageous embodiment, such an orifice can be arranged in the housing in the exhaust gas flow downstream of the membrane block and configured as a droplet separator. This provides additional functionality, since the orifice is specifically used to separate water from the liquid carried in the exhaust gas flow. Alternatively, the housing can include a water collection volume. The orifice can then be purposefully configured to supply the separated liquid droplets or separated water to the water collection volume. The water collection volume can have a drain valve, allowing the collected water to be drained from the water collection volume at a certain filling level or periodically.

[0021] According to another advantageous embodiment, it can be provided that a guide groove is formed on the inlet side of the orifice for guiding the droplets separated at the orifice into the collecting volume, thereby improving the supply of water produced by droplet separation at the orifice to the collecting volume.

[0022] According to another advantageous embodiment, it may be envisaged that guide ribs are arranged and / or molded on the inside of the housing upstream of the membrane block, on the membrane block and / or on the orifice, in order to improve the guidance of the intake air flow and / or the exhaust air flow, in particular towards the through-flowable edge region or the recirculation edge.

[0023] Alternatively or additionally, it may be envisaged that guide ribs are arranged and / or molded on the inside of the housing downstream of the membrane block to improve the guidance of the intake air flow and / or exhaust air flow away from the membrane block and / or the orifice, in particular away from the through-flowable edge region or the circulatable edge.

[0024] These guide ribs improve the flow guidance inside the housing of the air humidifier, in particular by improving the inflow into the orifice, especially towards the permeable edge region or recirculation edge of the orifice, thereby additionally supporting the orifice in uniforming the flow through the membrane block in the intake or exhaust air path.

[0025] An air humidifier according to one of the aforementioned features can be used in particular for use in a vehicle.

[0026] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the accompanying description based on the drawings.

[0027] It will be understood that the features set forth above and further below can be used not only in the combinations shown, but also in other combinations or alone without departing from the scope of the present invention. Components of higher-level units set forth above and further below, such as separately shown devices, apparatuses or arrangements, may form separate parts or components of the unit or may be integrated regions or divisions of the unit, even if shown differently in the drawings.

[0028] The drawings illustrate preferred embodiments of the present invention, which are described in more detail in the following description, where like reference numerals refer to identical or similar or functionally identical components. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic, largely simplified, cross-sectional view of an air humidifier in the region of the air supply path in the form of a circuit diagram. [Figure 2] 2 is a schematic view similar to FIG. 1, but showing the area of ​​the exhaust path. [Figure 3] 1A-1C are highly simplified schematic plan views of orifices in various embodiments. [Figure 4] 1A-1C are highly simplified schematic plan views of orifices in various embodiments. [Figure 5] 1A-1C are highly simplified schematic plan views of orifices in various embodiments.

[0030] 1 and 2, an air humidifier 1, which can be used in particular in fuel cell systems, for humidifying a relatively dry intake air flow 2, indicated by arrows in Fig. 1, with a relatively moist exhaust air flow 3, indicated by arrows in Fig. 2, includes a housing 4 having four connections 5. These four connections 5 form an intake air inlet 6, visible in Fig. 1, for feeding the intake air flow 2, an intake air outlet 7, visible in Fig. 1, for discharging the intake air flow 2, an exhaust air inlet 8, visible in Fig. 2, for feeding the exhaust air flow 3, and an exhaust outlet 9, visible in Fig. 2, for discharging the exhaust air flow 3.

[0031] The air humidifier 1 further comprises a membrane block 10 disposed within the housing 4, the membrane block 10 comprising a plurality of membranes 11 configured to be substantially impermeable to air and substantially permeable to water vapor. The membranes 11 are arranged within the membrane block 10 to form an intake air path 12, indicated by an arrow in Figure 1, through which the intake air flow 2 can pass, and an exhaust air path 13, indicated by an arrow in Figure 2, through which the exhaust air flow 3 can pass.

[0032] The air humidifier 1 presented here also has at least one orifice 14 arranged in the housing 4 on the outside of the membrane block 10. This orifice 14 is here arranged in the housing 4 in such a way that it can be penetrated by an air flow 15, indicated by an arrow in Figures 1 and 2 and formed by the intake air flow 2 or by the exhaust air flow 3. Furthermore, each orifice 14 is arranged and / or configured in such a way that it causes a uniform flow through the membrane block 10 in the intake air path 12 or the exhaust air path 13.

[0033] In FIG. 1, the orifice 14 is arranged in the intake air flow 2 and may also be referred to as the intake orifice 14.1 in the following. In the example of FIG. 1, the intake orifice 14.1 is arranged on the inlet side of the membrane block 10, i.e., on the intake side 16 of the intake side of the membrane block 10 or on the intake air inlet side 16. Alternatively, the intake orifice 14.1 may also be arranged on the outlet side 17 of the intake side of the membrane block 10 or on the intake air outlet side 17. The arrangement of the intake orifice 14.1 on the inlet side shown in FIG. 1 is preferred. In FIG. 2, the orifice 14 is arranged in the exhaust air flow 3 and may also be referred to as the exhaust orifice 14.2. In FIG. 2, the exhaust orifice 14.2 is arranged on the outlet side 18 of the exhaust side of the membrane block 10 or on the exhaust outlet side 18. Alternatively, an embodiment is also possible in which the exhaust orifice 14.2 is arranged on the inlet side 19 of the exhaust side of the membrane block 10 or on the exhaust inlet side 19. However, the arrangement of the exhaust orifice 14.2 on the outlet side shown in Figure 2 is preferred. The air humidifier 1 may in principle have two orifices 14 of this type, whereby the air humidifier 1 has one such orifice 14 in the intake air stream 2 and one in the exhaust air stream 3. Accordingly, the air humidifier 1 may have an intake orifice 14.1 and an exhaust orifice 14.2. Likewise, embodiments are possible in which the air humidifier 1 only has an intake orifice 14.1, i.e., only an orifice 14 arranged in the intake air stream 2. Likewise, embodiments are possible in which the air humidifier 1 only has an exhaust orifice 14.2, i.e., only an orifice 14 arranged in the exhaust air stream 3.

[0034] Each orifice 14 is arranged in the housing 4 between the membrane block 10 and one of the connections 5, in particular so that the orifice 14 is arranged in particular directly opposite the connection 5 in question. This results in a projection 22 of the cross section 20 through which the air can pass of the respective connection 5 entering the orifice 14 in the direction of the membrane block 10, parallel to the main direction 21, indicated by the arrow, of the air flow 15 at the respective connection 5. In Figures 1 and 2, this projection 22 is indicated by a dashed line, in particular relative to the intake air inlet 6 in Figure 1 and relative to the exhaust air outlet 9 in Figure 2.

[0035] Furthermore, each orifice 14 is arranged in the housing 4 so that it can be circulated on its edge by the air flow 15. For this purpose, each orifice 14 is designed so that an annular gap 24 or annular gap 24 is formed between the annular edge 23 of the orifice 14 and the housing 4, through which gap 24 the air flow 15 flows, allowing the orifice 14 to circulate on its edge.

[0036] Each orifice 14 is furthermore configured so that it can be pierced by an air flow 15. Expediently, the orifice 14 is configured so that its pierceable central region 25, marked with braces in Figures 1 and 2, is larger than its pierceable edge region 26, marked with braces in Figures 1 and 2 and annularly surrounding the central region 25. The central region 25 and the edge region 26 can also be seen in Figures 3 and 4.

[0037] The air humidifier 1 according to Fig. 1 has guide ribs 41 arranged and / or molded on the inside of the housing 4, respectively, on the upstream and downstream side of the membrane block 10. These guide ribs 41 are used in this case on the upstream side to improve the guidance of the intake air flow 2 towards the membrane block 10 and / or the orifice 14, and on the downstream side to improve the guidance of the intake air flow 2 away from the membrane block 10.

[0038] Here, the guide ribs 41 on the upstream side of the membrane block 10 help guide the supply air flow 2 towards the orifice 14. In particular, the guide ribs 41 help the flow into the permeable edge region 26 of the orifice 14 or into the circulatable edge 23 on the edge side, which also has a positive effect on the uniformity of the flow through the membrane block 10 in the supply air path 12 through the orifice 14.

[0039] It is also conceivable that the guide ribs 41 are arranged and / or molded inside the housing 4 of the air humidifier 1 only upstream of the membrane block 10 or only downstream of the membrane block 10 in the intake air flow 2 .

[0040] Likewise, it is also conceivable that corresponding guide ribs 41 are alternatively or additionally arranged and / or molded into the exhaust flow 3 upstream and / or downstream of the membrane block 10 (not shown).

[0041] According to FIG. 3, the orifice 14 can have a plurality of through-openings 27, 28, 29 through which the air flow 15 can pass. The through-openings 27 formed in the central region 25 can have a smaller through-opening cross-section 40 than the through-openings 29 formed in the edge region 26. In the example of FIG. 3, purely by way of example and without limiting generality, three different types or sizes of through-openings 27, 28, 29 are shown. The first through-openings 27 are located in the central region 25 and each have a relatively small through-opening cross-section 40. The second through-openings 28 are located in the intermediate region 30, which is located between the central region 25 and the edge region 26. The second through-openings 28 have an average through-opening cross-section 40 through which the air flow can pass, which is in any case larger than the cross-section 40 of the first through-openings 27. The third through-openings 29 are present in the edge region 26 and each have a relatively large cross-section 40 through which the flow can pass, which is larger than the average cross-section 40 of the second through-openings 28 and thus also larger than the small cross-section 40 of the first through-openings 27. In the example of Fig. 3, the through-openings 27, 28, 29 are designed circularly without any general limitation. However, the through-openings 27, 28, 29 can basically have any arbitrary geometric shape.

[0042] In an alternative embodiment shown in Fig. 4, the orifice 14 can have a plurality of through openings 31 through which the air flow 15 can flow, each extending from the central region 25 to the edge region 26. The through openings 31 have an opening width 32 that increases from the inside to the outside, i.e., towards the edge 23, so that the opening width 32 in the central region 25 is smaller than the opening width 32 in the edge region 26. The through openings 31 are designed triangularly in the example of Fig. 4 purely for illustrative purposes. The through openings 31 converge from the outside to the inside.

[0043] According to FIG. 5, the orifices 14 can optionally have a grid 33, which in FIG. 5 is arranged on the side of the orifice 14 facing the viewer. The grid 33 can here be arranged on the inlet or outlet side of the respective orifice 14. The grid 33 can be passed through by the air flow 15 and is otherwise configured to generate turbulence in the air flow 15 when passing through it. In the example of FIG. 5, the grid 33 completely covers the orifice 14. In particular, the grid 33 according to FIG. 5 can end flush with the edge 23 of the orifice 14. In another embodiment, the grid 33 can protrude beyond the edge 23 of the orifice 14. In particular, the grid 33 can extend into the housing 4 and, if appropriate, be supported on the housing 4, in particular bridging the annular gap 24.

[0044] In another embodiment, according to Figures 3 and 4, it may be assumed that an optional grid 34 is arranged or formed in each of the through openings 27, 28, 29, 31, completely filling the opening cross section 40 of the respective through opening 27, 28, 29, 31. In Figure 3, an optional grid 34 of this kind is shown purely by way of example in one of the third through openings 29, as representative of all the other through openings 27, 28, 29. Similarly, in Figure 4, an optional grid 34 of this kind is shown in only one of the through openings 31, as representative of all the other through openings 31.

[0045] 3 to 5, the orifices 14 have a circular shape, purely by way of example and without limiting generality. It is clear that the orifices 14 are expediently adapted to the cross-section of the membrane block 10 on the side facing the respective connection 5 and extending perpendicular to the main flow direction 21 of the respective connection 5. In particular, the membrane block 10 may be configured in the shape of a rectangular parallelepiped, so that the membrane block 10 has a rectangular cross-section on its inlet side 16, its outlet side 17, and / or its inlet side 19 and its outlet side 18. Accordingly, each orifice 14 can also have a rectangular shape.

[0046] In the embodiment shown in FIG. 2 , the orifice 14 arranged in the exhaust gas flow 3 downstream of the membrane block 10 in the housing 4, i.e., the exhaust gas orifice 14.2, is additionally configured as a droplet separator 35. Liquid water in the form of droplets is transported in the exhaust gas flow 3. At the exhaust gas outlet 18, the droplet-laden exhaust gas flow 3 leaves the membrane block 10 and encounters the orifice 14 arranged on the outlet side, where it accumulates and collects and can eventually flow down. The housing 4 comprises a collecting volume 36, which is formed, for example, in a collecting vessel 37 or is otherwise provided within the housing 4. The orifice 14, which functions here as a droplet separator 35, is configured to supply the separated water or separated liquid droplets to the collecting volume 36. The collecting volume 36 and / or the associated collecting vessel 37 can be provided with a drain valve 38, by means of which the water collected in the collecting volume 36 can be drained in a targeted manner. The orifice 14 acting as the droplet separator 35 may be formed with a number of guide grooves 39 on its inlet side, some of which are shown in Figure 4 purely by way of example. These guide grooves 39 are configured to guide the droplets separated on the orifice 14 into the collection volume 36. [Explanation of symbols]

[0047] 1 air humidifier 2. Intake air flow 3 Exhaust flow 4. Housing 5 Connection 6 Air intake 7 Air intake outlet 8 Exhaust inlet 9 Exhaust outlet 10 Membrane Block 11 membrane 12 Air supply path 13 Exhaust route 14 Orifice 15 Airflow 16 Air intake side 17 Intake air outlet side 18 Exhaust outlet side 19 Exhaust inlet side 20 cross section 21 Mainstream direction 22 Projection 23 Edge 24 Gap 25 Central area 26 Edge area 27 First through opening 28 Second through opening 29 Third through opening 30 Intermediate area 31 Through opening 32 Opening width 33 Lattice 34 Lattice 35 Droplet separator 36 Water collection volume 37 Water collection container 38 Drain valve 39 Guide groove 40 Opening cross section 41 Guide rib

Claims

1. An air humidifier (1) for humidifying a relatively dry intake air flow (2) with a relatively humid exhaust air flow (3), comprising: a housing (4) having four connections (5) forming an intake air inlet (6) for supplying the intake air flow (2), an intake air outlet (7) for discharging the intake air flow (2), an exhaust air inlet (8) for supplying the exhaust air flow (3), and an exhaust air outlet (9) for discharging the exhaust air flow (3); a membrane block (10) having a plurality of membranes (11), the membranes (11) being configured to be impermeable to air and permeable to water vapor, forming within the membrane block (10) an intake air path (12) through which the intake air flow (2) can pass and an exhaust air path (13) through which the exhaust air flow (3) can pass; In an air humidifier (1) comprising: The air humidifier (1) has at least one orifice (14), which is arranged in the housing (4) outside the membrane block (10) so that the orifice (14) can be flowed into by an air flow (15) formed by the intake air flow (2) or the exhaust air flow (3); The air humidifier (1) is characterized in that each of the orifices (14) is arranged and / or configured in the air supply path (12) or the air exhaust path (13) so that the orifice (14) causes uniform flow through the membrane block (10).

2. 2. The air humidifier (1) according to claim 1, wherein each of the orifices (14) is arranged in the housing (4) between the membrane block (10) and one of the connection parts (5), whereby the orifice (14) faces the connection part (5).

3. 3. The air humidifier (1) according to claim 1 or 2, wherein each orifice (14) is arranged in the housing (4) such that it can be circulated on its edge side by the air flow (15).

4. 3. The air humidifier (1) according to claim 1 or 2, wherein each of the orifices (14) is configured so as to be pierceable by the air flow (15).

5. 5. The air humidifier (1) according to claim 4, wherein the orifice (14) is configured so that the flow resistance in the flow-through central region (25) of the orifice (14) is greater than the flow-through resistance in the flow-through edge region (26) of the orifice.

6. The orifice (14) has a plurality of through openings (27, 28, 29) through which the air flow (15) can pass; 6. The air humidifier (1) according to claim 5, wherein the through openings (27) formed in the central region (25) have a smaller opening cross-section (40) through which flow can pass than the through openings (29) formed in the edge regions (26).

7. the orifice (14) has a plurality of through openings (31) through which the air flow (15) can pass, the through openings (31) extending from the central region (25) to the edge region (26); 6. The air humidifier (1) according to claim 5, wherein the through openings (31) in the central region (25) have a smaller through-flow opening width (32) than those in the edge regions (26).

8. 8. The air humidifier (1) according to claim 1, wherein a grid (33) for generating turbulence is arranged on the inlet or outlet side of each orifice (14).

9. The grid (33) completely covers the orifice (14); The orifice (14) has an annular edge (23), 9. An air humidifier (1) according to claim 8, wherein the grid (33) terminates flush with the edge (23) of the orifice (14) or protrudes beyond the edge (23) of the orifice (14).

10. 8. The air humidifier (1) according to claim 6 or 7, wherein a grid (34) is arranged or formed in each of the through openings (27, 28, 29, 31), and the grid (34) completely fills the opening cross section (40) of each of the through openings (27, 28, 29, 31).

11. Such an orifice (14) is located in the intake air flow (2) upstream or downstream of the membrane block (10) in the housing (4), and / or 11. The air humidifier (1) according to any one of claims 1 to 10, wherein such an orifice (14) is arranged in the exhaust gas flow (3) upstream or downstream of the membrane block (10) in the housing (4).

12. Such an orifice (14) is located in the exhaust stream (3) downstream of the membrane block (10) within the housing (4) and configured as a droplet separator (35); The housing (4) has a water collecting volume (36), 12. The air humidifier (1) according to any one of the preceding claims, wherein the orifice (14) is configured to supply the separated droplets to the collecting volume (36).

13. 13. The air humidifier (1) of claim 12, wherein the water collection volume (36) has a drain valve (38) whereby moisture collected in the water collection volume (36) is drained from the water collection volume (36) from a certain fill level or periodically.

14. 14. The air humidifier (1) according to claim 12 or 13, wherein a guide groove (39) is formed on the inlet side of the orifice (14) for guiding droplets separated at the orifice (14) to the water collecting volume (36).

15. and / or guide ribs (41) are arranged and / or molded into the membrane block (10) on the inside of the housing (4) upstream of the membrane block (10) and / or the orifice (14) to improve the guidance of the intake air flow (2) and / or the exhaust air flow (3), in particular towards the permeable edge region (26) or the recirculation edge (23) of the orifice (14); and / or 15. The air humidifier (1) according to claim 1, wherein guide ribs (41) are arranged and / or formed on the inside of the housing (4) downstream of the membrane block (10) for improving the guidance of the supply air flow (2) and / or the exhaust air flow (3) away from the membrane block (10) and / or the orifice (14), in particular away from the through-flow edge region (26) or the circulatable edge (23) of the orifice (14).

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