Air humidifier

Abstract

The invention relates to an air humidifier (1), in particular for a fuel cell system, for humidifying dry fresh air (4 ') by means of humid exhaust gas (5'), comprising a housing (2) and a humidification module (3) arranged in the housing (2), which humidification module has a membrane stack (11) through which a fresh air flow (4) and an exhaust gas flow (5) can flow, the invention relates to a humidifying module (3) comprising a membrane stack (11) for humidifying dry fresh air (4 ') by means of humid exhaust gas (5'), and the membrane stack (11) consists of membranes (12) which are impermeable to air but permeable to moisture, the membrane stack (11) having two end faces (13) which lie opposite one another in the module length direction (X), and the humidifying module (3) having two end plates (14), each of which is arranged on one of the end faces (13). The wear resistance can be improved if the respective end plate (14) is supported on the respective end face (13) by means of at least one elastic seal (15) preloaded in the module length direction (X).

Description

Technical Field

[0001] The invention relates to an air humidifier, in particular of a fuel cell system, for humidifying dry fresh air by means of moist exhaust air. Background Art

[0002] This type of air humidifier typically includes a housing and a humidification module. The housing surrounds the interior of the housing and has a fresh air inlet for supplying dry fresh air, a fresh air outlet for discharging humidified fresh air, an exhaust inlet for supplying moist exhaust air, and an exhaust outlet for discharging dehumidified exhaust air. The humidification module is installed in the interior of the housing and has a membrane stack, through which fresh air and exhaust air flows can flow separately in order to humidify the fresh air with the aid of the exhaust gas. The membrane stack is composed of a membrane that is impermeable to air but permeable to moisture. The membrane stack has two end faces that are opposite to each other in the longitudinal direction of the module. The humidification module has two end plates, each of which is arranged on one of the end faces.

[0003] To prevent leakage, the end plates are sealed against the corresponding end faces. Sealing connection techniques such as adhesive bonding can be used. However, it has been shown that during operation of the air humidifier, these connections or adhesive bonds are subject to mechanical stress and, therefore, high levels of wear. This can lead to damage or loosening of the adhesive connection. Damage or loosening of the adhesive connection reduces the sealing effect, potentially leading to undesirable leakage between the fresh air flow and the exhaust air flow. This reduces the efficiency of the air humidifier. Summary of the Invention

[0004] The present invention is directed to the problem of providing an improved or at least different embodiment of such an air humidifier, which has a high wear resistance, wherein preferably a high efficiency is sought and leakage in particular in the region of the end plate is to be avoided.

[0005] According to the invention, this problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0006] The present invention is based on the general concept of supporting the respective end plates on the respective end faces by means of at least one elastic seal, wherein the elastic seal is elastically preloaded in the longitudinal direction of the module. The present invention utilizes the recognition that during operation of the air humidifier, a pressure differential between the fresh air and the exhaust air is generated in the housing, which causes elastic deformation of the end plates. In conventional designs employing adhesive connections between the respective end plates and the respective end faces, this elastic deformation of the end plates places high mechanical stress on the adhesive connections. By using the preloaded elastic seal proposed in accordance with the present invention instead of an adhesive connection, the seal can follow the elastic deformation of the end plates without subjecting them to additional loads. During operation of the air humidifier, the deformation of the end plates caused by the pressure differential relieves the seal from load, allowing it to follow relative movements between the end plates and the associated end faces. The seal maintains its sealing effect. Consequently, the sealing connection or coupling between the respective end plates and the associated end faces is decoupled from wear, making the air humidifier proposed herein particularly wear-resistant. Disadvantageous leakage in the region of the end plate can also be avoided thereby, which increases the efficiency of the air humidifier.

[0007] When using an air humidifier in a fuel cell system, moisture is particularly water or water vapor. The membrane is permeable to moisture or water, while being substantially impermeable to air. In this context, the terms "wet," "dry," "dehumidified," and "humidified" are relative terms; dehumidified exhaust gas contains less moisture than wet exhaust gas, and humidified intake air contains more moisture than dry intake air.

[0008] A particularly advantageous embodiment is one in which the respective end plates are spaced apart from the respective end faces in the longitudinal direction of the module. This allows the end faces of the membrane stack, particularly those formed by the first or last membrane of the stack, to be used for the flow of fresh air or exhaust air, thereby increasing the efficiency of the humidifier. This measure also completely decouples the membrane stack from deformation of the respective end plates during operation of the humidifier, thereby reducing mechanical loads. This reduces wear and helps to increase the service life of the membrane stack.

[0009] During operation of the humidifier, a pressure differential can develop in the housing between the fresh air flow and the exhaust air flow. Typically, the pressure in the fresh air flow is higher than the pressure in the exhaust air flow. According to an advantageous embodiment, the respective end plates, outside the respective seals, can have a distance relative to the associated end face in the module length direction that, when a pressure differential exists, is greater by an extension or less by a compression in the module length direction than when no pressure differential exists. In other words, during operation of the humidifier, the respective end plates deform due to the pressure differential, causing the distance between the end plates and the respective end faces to increase or decrease depending on the pressure differential. Furthermore, the respective seals can be configured such that, in the relaxed state, they are preloaded more in the module length direction than in the preloaded, installed state, in which, when no pressure differential exists, the seal spans the distance between the respective end plate and the respective end face. In particular, when the humidifier is not in operation, there is no pressure differential. Furthermore, the respective seals can be configured such that the preload is greater than the extension of the respective end plates. This results in the seal being sufficiently preloaded to produce the desired sealing effect when the end plate undergoes elongation deformation, even in the case of the maximum deformation that may occur in the end plate during normal operation of the air humidifier. Only in the case of an overload, which does not occur during normal operation of the air humidifier, will the end plate, due to its deformation, separate far enough from the associated end face so that such movement of the elastic seal can no longer be compensated. In such an overload situation, leakage will occur, which, although temporarily reducing the efficiency of the air humidifier, will achieve pressure balance, which reduces the load and deformation of the end plate. Conversely, when the end plate undergoes compression deformation, the deformation and preload of the seal will increase, thereby ensuring the sealing effect. The elasticity of the seal should be appropriately selected so that even in the case of the maximum deformation that may occur in the end plate during normal operation of the air humidifier, the compression of the seal remains within the elastic range, thereby avoiding damage to the seal.

[0010] In this context, “configured” is synonymous with “configured” and / or “arranged”, so that the expression “configured so as to” is synonymous with the expression “configured and / or arranged so as to”.

[0011] In this context, the distance between the respective end plate and the associated end face transversely to the module length and the deformation of the seal in the central region of the end plates are expediently considered, since the greatest deformation of the end plates due to the pressure difference is to be expected there.

[0012] In an advantageous embodiment, the corresponding seal can be configured as an I-shaped seal, characterized by an elongated cross-section whose length runs parallel to the module's length. The seal configured as an I-shaped seal is compressed, i.e., squeezed or pressed, along the module's length, thereby being pre-tensioned along the module's length. If the end plate deforms during operation of the humidifier, the compressed seal can expand along the module's length and continue to provide the desired sealing effect.

[0013] In an alternative embodiment, the respective seal can be configured as a lip seal having a support foot that rests on the respective end plate or end face and a sealing profile that abuts the respective end face or end plate. The seal configured as a sealing lip can be prestressed in the longitudinal direction of the module by elastically deforming about a bending axis extending transversely to the longitudinal direction of the module. If the end plate deforms during operation of the humidifier, the elastically deformable sealing lip can follow the associated relative movement of the end plate with respect to the end face and continue to ensure the desired sealing effect.

[0014] In an advantageous refinement, the seal element, which is configured as a sealing lip, can be arranged such that the pressure difference between the fresh air flow and the exhaust air flow increases the prestressed contact of the respective seal element on the end face or the respective end plate. This can improve the sealing effect. Alternatively, the pressure difference can reduce the prestressing force.

[0015] The respective seal can be expediently bonded to the respective end plate and the respective end face, thereby simplifying the handling of the humidification module. In particular, a seal configured as an I-shaped seal can be bonded both to the end plate and to the end face.

[0016] In another embodiment, it can be configured that the corresponding sealing member is loosely attached to the corresponding end plate and the corresponding end surface, which can simplify the manufacture of the humidification module.

[0017] In another embodiment, the respective seals can be retained on or bonded to the respective end plates and loosely adhere to the respective end faces. Alternatively, the respective seals can be retained on or bonded to the respective end faces and loosely adhere to the respective end plates. This measure also simplifies the manufacture and operation of the humidification module. This embodiment is particularly suitable for seals configured as lip seals.

[0018] The membrane stack can be configured in such a way that it has two sides facing away from each other transversely to the longitudinal direction of the module, wherein the humidification module has a sealing frame on each of these two sides, which is arranged on the edge side of the corresponding side and is closed and surrounds the humidification module tightly on the housing. It can now be expedient to provide that the corresponding sealing frame also surrounds the two end plates on the corresponding side. In this way, the two end plates are sealed to the membrane stack via the corresponding sealing frame. In particular, the sealing frame can withstand the forces acting on the end plates during operation of the air humidifier, so that no deformation of the end plates occurs, especially in the area of ​​the corresponding sealing frame. The elastically prestressed seal that seals the corresponding end plate relative to the associated end face expediently extends from one sealing frame to the other sealing frame. During operation of the air humidifier, the corresponding end plate deforms in the area between the two sealing frames. The maximum deformation occurs essentially in the middle position between the two sealing frames.

[0019] According to an advantageous embodiment, the respective sealing frame can have circumferential side seals, by means of which the respective sealing frame is supported sealingly on the housing. The use of the side seals makes it possible to separate the functions of sealing and retaining, so that the side seals produce the sealing effect relative to the housing, while the sealing frame produces the retaining effect, which holds the membrane stack in the housing.

[0020] Advantageously, the membrane stack can include a fresh air inlet side fluidly connected to the fresh air inlet, a fresh air outlet side fluidly connected to the fresh air outlet, an exhaust inlet side fluidly connected to the exhaust inlet, and an exhaust outlet side fluidly connected to the exhaust outlet. Furthermore, the membrane stack can define a fresh air path fluidly connecting the fresh air inlet side with the fresh air outlet side, and an exhaust path fluidly connecting the exhaust inlet side with the exhaust outlet side. Within the membrane stack, the fresh air path and the exhaust path are fluidly isolated from each other, such that substantially no air exchange occurs between the fresh air flow and the exhaust flow, while moisture is transferred from the exhaust gas to the fresh air through the membranes.

[0021] According to a first embodiment, the fresh air inlet side and the exhaust air outlet side can be positioned opposite each other in a module transverse direction, which runs transverse to the module length, while the exhaust air inlet side and the fresh air outlet side can be positioned opposite each other in a module height direction, which runs transverse to both the module length and the module transverse direction. This results in a 90° deflection of the fresh air flow and a 90° deflection of the exhaust air flow within the membrane stack. This embodiment also allows the end plate to be positioned on a side surface of the membrane stack, that is, on an end surface not associated with an inlet or outlet. This simplifies sealing of the end plate.

[0022] According to a second embodiment, the fresh air inlet and fresh air outlet sides can be positioned opposite each other in a module transverse direction, which is transverse to the module length, while the exhaust air inlet and exhaust air outlet sides can be positioned opposite each other in a module height direction, which is transverse to both the module length and the module transverse direction. This allows the fresh air and exhaust air flows to be directed linearly through the membrane stack, intersecting within the stack. In this embodiment, the end plate is also located on a side of the membrane stack, that is, on the end surface not associated with an inlet or outlet. This simplifies sealing on the end plate.

[0023] According to another embodiment, each end plate can have two end regions facing away from each other in the module height direction. The end plates are supported on the respective end faces by two elastic seals prestressed in the module length direction. The two seals are each arranged at one of the two end regions of the end plate and extend transversely to the module. In particular, the two seals can extend from one sealing frame to the other. This design creates a relatively large area between the end plate and the associated end face for applying fresh air or exhaust air, which improves the efficiency of the air humidifier.

[0024] According to an advantageous embodiment, a sealing frame can be arranged on the fresh air inlet side, while in the first embodiment described above, another sealing frame is arranged on the exhaust air outlet side, and in the second embodiment described above, another sealing frame is arranged on the fresh air outlet side. This results in a particularly simple design for the air humidifier. This also enables a configuration in which the preloaded seals arranged between the respective end plates and the associated end faces can extend from one sealing frame to the other in the transverse direction of the module. This achieves a complete seal in the respective end regions.

[0025] Advantageously, the membranes within the membrane stack are stacked one above the other in the longitudinal direction of the module. In other words, the stacking direction preferably extends parallel to the longitudinal direction of the module, and the membranes within the membrane stack are stacked one above the other in this stacking direction. In particular, the stacking direction can define the longitudinal direction of the module. The membranes form pockets or chambers, namely, fresh air chambers through which fresh air flows and exhaust chambers through which exhaust air flows. Advantageously, the fresh air chambers and exhaust chambers alternate in the stacking direction, so that the fresh air and exhaust air flows overlap over a large area within the membrane stack without mixing.

[0026] The membrane stack can be advantageously configured in a rectangular parallelepiped shape, which simplifies its manufacture. The module's longitudinal dimension can be appropriately greater than its transverse dimension and greater than its height dimension. In particular, the module's transverse and height dimensions can be identical.

[0027] In a further advantageous embodiment, the respective end plate can have at least one protruding, in particular straight, rib on its outer side facing away from the membrane stack, extending transversely to the longitudinal direction of the module, in particular parallel to the transverse direction of the module, and supported on the housing. In this way, forces acting on the respective end plate due to pressure differences during operation can be at least partially absorbed by the housing, thereby reducing deformation of the end plate.

[0028] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated description of the drawings.

[0029] It goes without saying that the features described above and those further explained below can be used not only in the combination given, but also in other combinations or alone, without departing from the scope of the invention as defined in the claims. The components described above and those further mentioned below that belong to a superordinate unit (such as a device, apparatus, or assembly) may constitute individual components or assemblies of the unit, or may be integral regions or parts of the unit, although they are shown in different ways in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Preferred exemplary embodiments of the present invention are illustrated in the drawings and are further explained in the following description, wherein the same reference numerals designate identical or similar or functionally identical components.

[0031] The accompanying drawings schematically show:

[0032] Figure 1 Isometric view of an air humidifier,

[0033] Figure 2 Isometric cutaway view of an air humidifier,

[0034] Figure 3 Isometric longitudinal section view of an air humidifier,

[0035] Figure 4 Isometric view of an air humidifier with the housing shown transparently,

[0036] Figure 5 Isometric view of the humidification module in the end plate area in the unloaded state,

[0037] Figure 6 Figure 5 , but in a loaded state,

[0038] Figure 7 Longitudinal section through the humidification module in the area of ​​the end plate in the unloaded state,

[0039] Figure 8 Figure 7 , but in a loaded state,

[0040] Figure 9 In a further embodiment, an isometric view of the humidification module in the region of the end plate,

[0041] Figure 10 and Figure 1 A similar view, but for another embodiment,

[0042] Figure 11 and Figure 2 A similar view, but for another embodiment,

[0043] Figure 12 and Figure 3 A similar view, but for another embodiment,

[0044] Figure 13 and Figure 4 Similar view, but for another embodiment. DETAILED DESCRIPTION

[0045] according to Figures 1 to 4 as well as Figures 10 to 13 The air humidifier 1 includes a housing 2 and a humidification module 3 arranged in the housing 2. Figure 1 Not visible in . Figure 4 and Figure 10 In FIG, the housing 2 is shown transparently. Figures 1 to 4 as well as Figures 10 to 13 In the figure, the fresh air flow 4 and the exhaust gas flow 5 flowing through the housing 2 and the humidification module 3 during the operation of the air humidifier 1 are indicated by arrows. The fresh air flow 4 supplies dry fresh air 4' to the air humidifier 1 and discharges humidified fresh air 4" from the air humidifier 1. The exhaust gas flow 5 supplies moist exhaust gas 5' to the air humidifier 1 and discharges dehumidified exhaust gas 5" from the air humidifier 1. The air humidifier 1 is used to humidify the dry fresh air 4' with the help of the moist exhaust gas 5' and can be used in particular in a fuel cell system. For example, the air humidifier 1 can humidify the cathode fresh air with the help of the cathode exhaust gas in a fuel cell system.

[0046] The housing 2 encloses a housing interior 6 and has a fresh air inlet 7 for supplying dry fresh air 4 ′, a fresh air outlet 8 for discharging humidified fresh air 4 ″, an exhaust air inlet 9 for supplying moist exhaust air 5 ′, and an exhaust air outlet 10 for discharging dehumidified exhaust air 5 ″.

[0047] The humidification module 3 is mounted in the housing interior 6 and includes a membrane stack 11. The fresh air flow 4 and the exhaust air flow 5 flow through the membrane stack 11 and are formed by membranes 12 made of a membrane material that is impermeable to air but permeable to moisture. The membrane stack 11 is configured in a rectangular parallelepiped shape, thereby defining a module longitudinal direction X, a module transverse direction Y, and a module height direction Z, which are perpendicular to each other. Within the membrane stack 11, the membranes 12 can be stacked one on top of the other in a stacking direction S, which preferably extends parallel to the module longitudinal direction X. In particular, the stacking direction S can define the module longitudinal direction X.

[0048] according to Figures 3 to 9 、 Figure 12 and Figure 13 , the membrane stack 11 has two end faces 13, which are opposite to each other in the module length direction X or away from each other in the module length direction X. The humidification module 3 has two end plates 14, which are respectively assigned to one of the end faces 13 and are respectively arranged on one of the two end faces 13. Here, the corresponding end plate 14 is supported on the corresponding assigned end face 13 by at least one seal 15. Here, the corresponding seal 15 is elastically configured and elastically pre-tightened in the module length direction X. In the embodiment shown, two such seals 15 are respectively provided on each end plate 14. In particular, the seals extend parallel to the module transverse direction Y and are spaced apart from each other in the module height direction Z on the corresponding end plate 14.

[0049] The corresponding end plate 14 contacts the associated end face 13 via the corresponding seal 15. In addition, the corresponding end plate 14 is positioned spaced apart from the associated end face 13. Figures 7 to 9 A cavity 16 is formed, which can be supplied with fresh air or exhaust air and through which the fresh air flow 4 or the exhaust air flow 5 flows during operation of the air humidifier 1 .

[0050] During operation of the air humidifier 1 , a pressure difference Δp can form in the housing 2 between the fresh air flow 4 and the exhaust air flow 5 , according to Figure 6 and Figure 8 , the pressure difference may cause elastic deformation, in particular extension or compression, of the corresponding end plate 14. Figures 5 to 8 , the corresponding end plate 14 has a distance 17 relative to the corresponding end face 13 in the module length direction X, which exists when there is no pressure difference Δp and becomes larger or smaller when there is a pressure difference Δp. Figure 6 and Figure 8, the elongation deformation of the end plate 14 can be seen, in which the end plate 14 bends outwards. As a result, the distance 17 increases to 17'. In the other case, the end plate 14 undergoes a compression deformation, in which the end plate 14 bends inwards, which causes the distance 17 to decrease to 17", but this is not shown here. Here, the maximum increase or the maximum decrease in the distance 17 occurs in the middle part of the end plate 14 with respect to the module transverse direction Y. Accordingly, the distance 17 in the presence of a pressure difference Δp is greater or less than in the absence of a pressure difference Δp by an unspecified elongation or compression. In other words, the elongation or compression represents the difference between the increased distance 17' or the decreased distance 17" in the presence of a pressure difference Δp and the distance 17 in the absence of a pressure difference Δp. The increased distance 17' and the decreased distance 17" are not necessarily equal in value.

[0051] The seal 15 is configured such that in the completely relaxed state, in particular in the disassembled state (not shown in the figures), it is prestressed in the module length direction X by an unspecified amount than in the prestressed installed state, for example in the Figure 5 and Figure 7 As depicted in FIG, in the installed state, when no pressure differential Δp exists, the seal spans the distance 17 between the respective end plate 14 and the associated end face 13. Here, the seal's preload is expediently greater than the elongation of the respective end plate 14. In other words, due to its elasticity, the seal 15 can stretch itself in the module longitudinal direction X to a greater extent than the maximum increase in distance 17 expected due to the deformation of the end plate 14 caused by the pressure differential Δp. This ensures that, even with the expected maximum deformation of the end plate 14, the correspondingly increased distance 17 or 17' can still be reliably spanned by the seal 15. Figure 6 It is clearly shown how the elasticity of the seal 15 reliably spans a distance 17 that varies in the transverse direction Y of the module.

[0052] according to Figures 3 to 8 In the example shown, the seal 15 can be configured as an I-shaped seal. Such an I-shaped seal has an elongated cross-section, with its length direction parallel to the direction of action of the seal 15. In the example shown, the seal 15 acts in the module longitudinal direction X and is therefore oriented with its length direction parallel to the module longitudinal direction X. This allows the seal 15 to be compressed, thereby pre-tightening the seal 15 in the module longitudinal direction X.

[0053] In contrast, Figure 9 An embodiment is shown in which the seal 15 is configured as a lip seal. The lip seal has a support foot 18 and a sealing contour 19. Figure 9In the example shown, the supporting foot 18 is held on the corresponding end plate 14. For example, the supporting foot 18 can be inserted into a groove 20, which is constructed on the inner side of the end plate 14 facing the associated end face 13. The sealing contour 19 fits on the end face 13. In an alternative structural form, the supporting foot 18 can also be held on the end face 13, while the sealing contour 19 fits on the end plate 14. However, the configuration shown here is preferred. The pre-tensioning of the seal 15 in the module length direction X is produced by elastically bending the seal 15 around a bending axis 21 running transversely to the module length direction X. In Figure 9 In the example of , the bending axis 21 extends parallel to the module transverse direction Y. Figure 9 In the embodiment shown, the seal 15 is also arranged such that during operation of the air humidifier 1 , a pressure difference Δp between the fresh air flow 4 and the exhaust air flow 5 increases or decreases the preload of the seal 15 on the end face 13 . Figure 9 The pressure difference Δp preferably acts on the seal 15 , so that an overpressure prevails in the cavity 16 . As a result, the sealing contour 19 is pressed against the end face 13 .

[0054] exist Figure 9 In the embodiment shown, the seal 15 can be bonded to the end plate 14 in the region of the support foot 18. However, this bonding is optional. In the region of the sealing contour 19, the seal 15 rests loosely on the end face 13.

[0055] And in Figures 3 to 8 、 Figure 12 and Figure 13 In the embodiment shown, it can be provided that the seal 15 is held on the end plate 14, in particular bonded thereto, and rests loosely on the end face 13. A reverse configuration is also conceivable, in which the seal 15 is fixed to the end face 13, in particular bonded thereto, while resting loosely on the end plate 14. It is also conceivable that the seal 15 is fixed to both the end plate 14 and the end face 13, or is bonded thereto.

[0056] according to Figures 2 to 4 as well as Figures 11 to 13, the membrane stack 11 has two side faces 22, 23, which face away from each other transversely to the module length direction X. In the example shown, the two side faces 22, 23 face away from each other in the module transverse direction Y. The humidification module 3 has a sealing frame 24 on each of these two side faces 22, 23. The corresponding sealing frame 24 is arranged on the edge side and in a closed surrounding manner on the corresponding side faces 22, 23. The corresponding sealing frame 24 tightly supports the humidification module 11 on the housing 2 on the corresponding side faces 22, 23. In the embodiment shown, it is also provided that the corresponding sealing frame 24 is configured so that it also surrounds the two end plates 14 on the corresponding side faces 22, 23. As a result, the corresponding sealing frame 24 surrounds the outer periphery of the humidification module 3 and extends along the end plates 14 on the outside. Here, the surrounding direction of the sealing frame 24 surrounds an axis parallel to the module transverse direction Y.

[0057] according to Figure 2 and Figure 4 as well as Figure 11 and Figure 13 , the corresponding sealing frame 24 can have a surrounding side seal 25. The corresponding sealing frame 24 is tightly supported on the housing 2 by the corresponding side seal 25.

[0058] according to Figures 2 to 4 as well as Figures 11 to 13 The membrane stack 11 has a fresh air inlet side 26 fluidly connected to the fresh air inlet 7, a fresh air outlet side 27 fluidly connected to the fresh air outlet 8, an exhaust gas inlet side 28 fluidly connected to the exhaust gas inlet 9, and an exhaust gas outlet side 29 fluidly connected to the exhaust gas outlet 10. Figure 2 and Figure 11 A fresh air path 30 fluidically connecting the fresh air inlet side 26 with the fresh air outlet side 27 and an exhaust gas path 31 fluidly connecting the exhaust gas inlet side 28 with the exhaust gas outlet side 29 are formed in the membrane stack 11 .

[0059] exist Figures 1 to 4 In one or the first embodiment shown, the fresh air inlet side 26 and the exhaust gas outlet side 29 are opposite each other in the module transverse direction Y. The exhaust gas inlet side 28 and the fresh air outlet side 27 are opposite each other in the module height direction Z. Thus, in this embodiment, two sealing frames 24 are located on the fresh air inlet side 26 and the exhaust gas outlet side 29, which form the aforementioned side faces 22 and 23 that are opposite each other transverse to the module length direction X.

[0060] In contrast, in Figures 10 to 13In the further or second embodiment shown, the fresh air inlet side 26 and the fresh air outlet side 27 are opposite each other in the module transverse direction Y. The exhaust air inlet side 28 and the exhaust air outlet side 29 are opposite each other in the module height direction Z. Thus, in the further embodiment shown here, two sealing frames 24 are located on the fresh air inlet side 26 and the fresh air outlet side 27, which form the aforementioned side faces 22 and 23 that are opposite each other transversely to the module length direction X.

[0061] from Figure 3 and Figure 12 In particular it can be seen that the respective end plate 14 has two end regions 32, 33 facing each other in the module height direction Z. Figure 3 and Figure 12 In the figure, an upper end region 32 and a lower end region 33 can be seen on each end plate 14. The respective end plate 14 is supported on the associated end face 13 via two seals 15 of the aforementioned type, wherein the respective seal 15 is elastically prestressed in the module longitudinal direction X. The two seals 15 are each arranged at one of the two end regions 32, 33 of the respective end plate 14 and are configured to extend longitudinally in the module transverse direction Y. Furthermore, the seals 15 preferably extend continuously from one sealing frame 24 to the other sealing frame 24 in the module transverse direction Y. Thus, the two seals 15 define a cavity 16 in the module height direction Z, formed between the respective end plate 14 and the associated end face 13 in the module longitudinal direction X.

[0062] according to Figure 3 、 Figure 4 、 Figure 12 and Figure 13 , the respective end plates 14 may have at least one protruding rib 34 on the outer side facing away from the membrane stack 11, extending transversely to the module length direction X. The respective end plates 14 are supported on the housing 2 by means of this rib. In the example, each rib 34 extends linearly and parallel to the module transverse direction Y. Here, each rib 34 may be embedded in the sealing frame 24. For example, the sealing frame 24 may be injection molded or foamed onto the membrane stack 11 and the two end plates 14.

Claims

1. An air humidifier (1) for humidifying dry fresh air (4') by means of moist exhaust air (5'), in particular for a fuel cell system, the air humidifier - having a housing (2) which encloses a housing interior (6) and has a fresh air inlet (7) for supplying dry fresh air (4'), a fresh air outlet (8) for discharging humidified fresh air (4"), an exhaust air inlet (9) for supplying moist exhaust air (5') and an exhaust air outlet (10) for discharging dehumidified exhaust air (5"), - a humidification module (3) which is installed in the housing interior (6) and has a membrane stack (11) through which a fresh air flow (4) and an exhaust air flow (5) can flow in order to humidify the dry fresh air (4') by means of the moist exhaust air (5'), and which consists of a membrane (12) which is impermeable to air but permeable to moisture, -in, The membrane stack (11) has two end faces (13), which are opposite to each other in the module length direction (X); - wherein the humidification module (3) has two end plates (14), each of which is arranged on one of the end surfaces (13); - wherein the respective end plate (14) is supported on the respective end face (13) by at least one elastic seal (15) prestressed in the longitudinal direction (X) of the module.

2. The air humidifier (1) according to claim 1, It is characterized by: - during operation of the air humidifier (1), a pressure difference (Δp) is established in the housing (2) between the fresh air flow (4) and the exhaust air flow (5), - the respective end plate (14) has a distance (17) relative to the respective end face (13) in the module length direction (X), said distance being greater by an extension or less by a compression in the module length direction (X) when a pressure difference (Δp) is present than when no pressure difference (Δp) is present, - the respective seal (15) is configured such that, in the relaxed state, the seal is prestressed in the longitudinal direction (X) of the module more than in the prestressed installed state, in which state the seal spans the distance (17) between the respective end plate (14) and the respective end face (13) in the absence of a pressure difference (Δp), - The corresponding seal (15) is further configured such that the pre-tension of the seal (15) is greater than the elongation of the corresponding end plate (14).

3. The air humidifier (1) according to claim 1 or 2, It is characterized by: - the respective seal (15) is configured as an I-shaped seal having an elongated cross section which is oriented parallel to the module length direction (X) with respect to its length direction; The respective seal (15) is prestressed in the longitudinal direction (X) of the module in the following manner: the seal is compressed in the longitudinal direction (X) of the module.

4. The air humidifier (1) according to claim 1 or 2, It is characterized by: - the respective seal (15) is configured as a lip seal, comprising a support foot (18) held on the respective end plate (14) or the respective end face (13) and a sealing contour (19) abutting against the respective end face (13) or the respective end plate (14); The respective seal (15) is prestressed in the longitudinal direction (X) of the module by elastically bending the seal about a bending axis (21) extending transversely to the longitudinal direction (X) of the module.

5. The air humidifier (1) according to claim 4, It is characterized by: The respective seal (15) is arranged such that a pressure difference (Δp) between the fresh air flow (4) and the exhaust gas flow (5) increases or decreases the prestressing of the respective seal (15) on the respective end face (13) or the respective end plate (14).

6. The air humidifier (1) according to any one of claims 1 to 5, It is characterized by: - The corresponding sealing element (15) is bonded to the corresponding end plate (14) and the corresponding end surface (13).

7. The air humidifier (1) according to any one of claims 1 to 5, It is characterized by: - the corresponding seal (15) is held on the corresponding end plate (14) or bonded to the end plate and is loosely fitted on the corresponding end face (13); or The corresponding sealing element (15) is held on the corresponding end surface (13) or bonded to the end surface and is loosely attached to the corresponding end plate (14).

8. An air humidifier (1) according to any one of the preceding claims, It is characterized by: The membrane stack (11) has two side faces (22, 23) facing away from each other transversely to the longitudinal direction (X) of the module, - the humidifying module (3) has a sealing frame (24) on each of the two side surfaces (22, 23), which is arranged around the edges of the respective side surface (22, 23) and supports the humidifying module (3) on the housing (2) in a sealing manner, The respective sealing frame (24) also surrounds the two end plates (14) on the respective side surfaces (22, 23).

9. The air humidifier (1) according to claim 8, It is characterized by: The respective sealing frame (24) has a circumferential side seal (25), by means of which the respective sealing frame (24) is supported sealingly on the housing (2).

10. An air humidifier (1) according to any one of the preceding claims, It is characterized by: the membrane stack (11) has a fresh air inlet side (26) fluidically connected to the fresh air inlet (7), a fresh air outlet side (27) fluidically connected to the fresh air outlet (8), an exhaust gas inlet side (28) fluidically connected to the exhaust gas inlet (9), and an exhaust gas outlet side (29) fluidically connected to the exhaust gas outlet (10), A fresh air path (30) fluidically connecting the fresh air inlet side (26) with the fresh air outlet side (27) and an exhaust gas path (31) fluidically connecting the exhaust gas inlet side (28) with the exhaust gas outlet side (29) are formed in the membrane stack (11); - the fresh air inlet side (26) and the fresh air outlet side (27) are opposite to each other with respect to a module transverse direction (Y) running transversely to the module length direction (X), while the exhaust air inlet side (28) and the exhaust air outlet side (29) are opposite to each other with respect to a module height direction (Z) running transversely to the module length direction (X) and the module transverse direction (Y).

11. The air humidifier (1) according to claim 10, It is characterized by: - the respective end plate (14) has two end regions (32, 33) facing away from each other in the module height direction (Z); - the respective end plates (32, 33) are supported on the respective end faces (13) via two such elastic seals (15), the seals being prestressed in the longitudinal direction (X) of the module; The two seals (15) are each arranged on one of the two end regions (32, 33) on the respective end plate (14) and extend longitudinally in the module transverse direction (Y).

12. An air humidifier (1) according to claim 10 or 11 and claim 8 or 9, It is characterized by: One sealing frame (24) is arranged at the fresh air inlet side (26), and another sealing frame (24) is arranged at the fresh air outlet side (27).

13. An air humidifier (1) according to any one of the preceding claims, It is characterized by: - The membranes (12) in the membrane stack (11) are stacked on top of each other in the module length direction (X).

14. An air humidifier (1) according to any one of the preceding claims, It is characterized by: - The membrane stack (11) is configured in a rectangular parallelepiped shape.

15. An air humidifier (1) according to any one of the preceding claims, It is characterized by: - The corresponding end plate (14) has at least one protruding rib (34) on the outer side facing away from the membrane stack (11) and extending transversely to the module length direction (X) or parallel to the module transverse direction (Y), which is supported on the housing (2).

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