Air humidifier

Abstract

To provide an air humidifier for humidifying dry fresh air using moist exhaust air, particularly in a fuel cell system.SOLUTION: An air humidifier for humidifying dry fresh air with humid exhaust air, includes a housing, and a humidifier block arranged within the housing, the humidifier block has a membrane stack formed by a plurality of membranes, through which the fresh air flow and the exhaust air flow can pass and which are impermeable to air but permeable to moisture, in order to humidify the dry fresh air with the humid exhaust air, the membrane stack has two end sides located on opposite sides in the longitudinal direction of the block, and the humidifier block has two end plates, each of which is arranged on one of the end sides.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an air humidifier for humidifying dry fresh air using moist exhaust air, especially in a fuel cell system.

[0002] Such an air humidifier typically includes a housing and a humidifier block. The housing encloses a housing interior and includes a fresh air inlet for supplying dry fresh air, a fresh air outlet for discharging humidified fresh air, a waste air inlet for supplying moist waste air, and a waste air outlet for discharging dehumidified waste air. The humidifier block is inserted into the housing interior and includes a membrane stack through which the fresh air flow and the waste air flow can flow separately to humidify the fresh air with the waste air. The membrane stack is formed by a plurality of membranes that are impermeable to air but permeable to moisture. In this case, the membrane stack has two end sides located on opposite sides in the longitudinal direction of the block. The humidifier block includes two end plates, each of which is disposed on one of the end sides.

[0003] To prevent leakage, the end plates are sealed on each end side. Sealing bonding techniques, such as gluing, can be used. However, it has been found that such bonding or gluing is subjected to mechanical loads during operation of the air humidifier, which results in high wear. This can lead to damage or separation of the adhesive bond. If the adhesive bond is damaged or separated, the sealing effect is reduced, which can lead to undesirable leakage between the fresh air flow and the exhaust air flow. This reduces the efficiency of the air humidifier.

[0004] The present invention addresses the problem of providing an improved or at least one alternative design for such air humidifiers, which is distinguished by high wear resistance, preferably aiming at high efficiency and avoiding leakage, especially in the region of the end plates.

[0005] 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.

[0006] The present invention is based on the general idea of ​​supporting each end plate on each end side by at least one elastic sealing element, which is elastically preloaded in the longitudinal direction of the block. The present invention utilizes the recognition that, during operation of the air humidifier, a pressure difference forms between the fresh air and the exhaust air in the housing, which causes elastic deformation of the end plates. In conventional designs that operate using adhesive bonds between each end plate and each end side, this elastic deformation of the end plates results in high mechanical loads on the adhesive bonds. The use of preloaded elastic sealing elements instead of adhesive bonds proposed by the present invention allows the sealing elements to follow the elastic deformation of the end plates without additional load being applied to the sealing elements. During operation of the air humidifier, the deformation of the end plates due to the pressure difference relieves the sealing elements, allowing them to follow the relative movement between the end plate and the associated end side, thereby maintaining their sealing function. As a result, the tight connection or coupling between each end plate and the associated end face is decoupled from wear, so that the proposed air humidifier is distinguished by particularly increased wear resistance, which also prevents undesirable leaks in the area of ​​the end plates, which increases the efficiency of the air humidifier.

[0007] The moisture is water or water vapor, particularly if an air humidifier is used in the fuel cell system. The membrane is permeable to moisture or water but substantially impermeable to air. In this context, the terms "humid," "dry," "dehumidified," and "humidified" may be interpreted as relative, such that dehumidified exhaust air has a lower moisture content than humid exhaust air, and humidified supply air has a higher moisture content than dry supply air.

[0008] An embodiment in which each end plate is spaced apart from each end side in the longitudinal direction of the block is particularly advantageous. In this way, the end side of the membrane stack, which may be formed by the first or last membrane of the membrane stack, can additionally be used for the flow of fresh or exhaust air. This increases the efficiency of the air humidifier. Furthermore, this measure completely isolates the membrane stack from deformation of the end plates during operation of the air humidifier, thus mechanically reducing its load. This reduces wear and promotes a longer life for the membrane stack.

[0009] During operation of the air humidifier, a pressure difference may form between the fresh air flow and the exhaust air flow within the housing. Typically, the pressure in the fresh air flow is higher than the pressure in the exhaust air flow. In a preferred embodiment, each end plate may be spaced apart from the respective end face in the longitudinal direction of the block, except at the location of the respective sealing element. When a pressure difference is applied, this distance in the longitudinal direction of the block is expanded or contracted by a predetermined amount more than when no pressure difference is present. In other words, during operation of the air humidifier, each end plate is deformed based on the pressure difference, and its distance from the associated end face increases or decreases depending on the pressure difference. Furthermore, each sealing element may be configured such that, in the relaxed state, it is larger in the longitudinal direction of the block by a predetermined preload amount than in the preloaded mounted state, and in the preloaded mounted state, it fills the gap between the respective end plate and the respective end face in the absence of a pressure difference. A pressure difference does not exist, particularly when the air humidifier is not operating. Furthermore, each sealing element may be configured so that its preload is greater than the extension of the corresponding end plate. As a result, during extension of the end plate, the sealing element is still sufficiently preloaded to provide the desired sealing effect, even at the maximum deformation of the end plate that can occur during normal operation of the air humidifier. Only when an overload, which does not occur during normal operation of the air humidifier, is applied will the end plate move too far away from the associated end face due to its deformation, and this movement can no longer be compensated for by the elastic sealing element. Such an overload then results in leakage. While this leakage does temporarily reduce the efficiency of the air humidifier, it also provides pressure compensation, which reduces the load and deformation of the end plate. During contraction of the end plate, the deformation of the sealing element and its preload increase, ensuring the sealing effect. The elasticity of the sealing member is purposefully set so that even at the maximum deformation of the end plate that may occur during orderly operation of the air humidifier, the contraction of the sealing member remains within the elastic range, and damage to the sealing member can be avoided.

[0010] In this context, "configured" is synonymous with "formed" and / or "adjusted," and therefore the phrase "configured to" is synonymous with the phrases "formed to" and / or "adjusted to."

[0011] In this case, the distance between each end plate and the associated end face, as well as the deformation of the sealing element, is preferably observed in the central region of the end plate in a direction perpendicular to the longitudinal direction of the block, since in this region the greatest deformation of the end plate due to the pressure difference is to be expected.

[0012] In a preferred embodiment, each sealing element may be configured as an I-shaped sealing element. The I-shaped sealing element is characterized by an elongated cross section oriented parallel to the longitudinal direction of the block. The I-shaped sealing element is preloaded in the longitudinal direction of the block by being compressed, i.e., pressed together or compressed, in the longitudinal direction of the block. When deformation of the end plates occurs during operation of the air humidifier, the compressed sealing element can expand in the longitudinal direction of the block, thereby still ensuring the desired sealing effect.

[0013] In an alternative embodiment, each sealing element may be configured as a lip seal. The lip seal has a retaining base held by the respective end plate or end face and a sealing contour in contact with the respective end face or end plate. The sealing element configured as a sealing lip may be preloaded in the longitudinal direction of the block by being elastically bent about a bending axis extending perpendicular to the longitudinal direction of the block. When deformation of the end plate occurs during operation of the air humidifier, the elastically deformed sealing lip follows the relative movement of the end plate with the deformation of the end face, thereby ensuring the desired sealing effect.

[0014] In an advantageous refinement, the sealing elements formed as sealing lips can be arranged in such a way that the pressure difference between the fresh air flow and the exhaust air flow increases the preloaded contact of the respective sealing element against the end face or end plate, thereby improving the sealing effect. Alternatively, the pressure difference can reduce the preload.

[0015] Expediently, each seal can be glued to the end plate and to the end face, which facilitates handling of the humidifier block. In particular, seals configured as I-shaped seals can be glued to both the end plate and the end face.

[0016] In contrast, in a further embodiment, it may be provided that each sealing element is in loose contact with both the end plate and the end face, which may facilitate the manufacture of the humidifier block.

[0017] In yet another embodiment, each sealing element may be held by or glued to the respective end plate and loosely contact the respective end face. Alternatively, each sealing element may be held by or glued to the respective end face and loosely contact the respective end plate. This measure also facilitates the manufacture and handling of the humidifier block. This embodiment is particularly suitable for sealing elements configured as lip seals.

[0018] The membrane stack may be configured with two sides that are positioned back to back in a direction perpendicular to the longitudinal direction of the block. In this case, the humidifier block has a sealing frame on each of these sides, which is arranged in a closed, circular manner on each side at the edges and tightly supports the humidifier block in the housing. It may be advantageous for each sealing frame to also surround the end plates on each side. This ensures that the end plates are tightly connected to the membrane stack via the respective sealing frames. In particular, the sealing frames can withstand forces acting on the end plates during operation of the air humidifier, so that deformation of the end plates does not occur, especially in the region of the respective sealing frames. The elastically preloaded sealing elements that seal each end plate against its associated end side then suitably extend from one sealing frame to the other. During operation of the air humidifier, deformation of each end plate occurs in the region between the two sealing frames. In that case, the maximum deformation occurs substantially in the middle between the two seal frames.

[0019] In yet another advantageous embodiment, each seal frame can have an annular side seal, via which it is tightly supported on the housing. By using the side seal, the sealing function and the retention function can be separated from each other, so that the side seal provides a sealing effect on the housing, while the seal frame provides a retention effect for holding the membrane stack in the housing.

[0020] Expediently, the membrane stack may have a fresh air inlet side fluidly connected to the fresh air inlet, i.e., connected in a fluid-flowing manner to the fresh air outlet, a fresh air outlet side fluidly connected to the fresh air outlet, a waste air inlet side fluidly connected to the waste air inlet, and a waste air outlet side fluidly connected to the waste air outlet. Furthermore, the membrane stack may form a fresh air channel fluidly connecting the fresh air inlet side to the fresh air outlet side, and a waste air channel fluidly connecting the waste air inlet side to the waste air outlet side. Inside the membrane stack, the fresh air channel and the waste air channel are separated from each other in a fluid-tight manner, so that essentially no air exchange takes place between the fresh air stream and the waste air stream, whereas moisture is transported from the waste air to the new air through the membrane.

[0021] In the first embodiment, the fresh air inlet and the exhaust air outlet can be located on opposite sides of the block transverse direction, which extends perpendicular to the block longitudinal direction. Alternatively, the exhaust air inlet and the fresh air outlet can be located on opposite sides of the block height direction, which extends perpendicular to the block longitudinal direction and perpendicular to the block 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 achieves the advantage that the end plates are located on the sides of the membrane stack, i.e., on the end faces that do not correspond to the inlet and outlet ports. This facilitates the creation of a seal at the end plates.

[0022] In a second embodiment, the fresh air outlet side and the fresh air outlet side can be located on opposite sides of the block transverse direction, which extends perpendicular to the block longitudinal direction, while the exhaust air inlet side and the exhaust air outlet side can be located opposite each other in the block height direction, which extends perpendicular to the block longitudinal direction and perpendicular to the block transverse direction. This allows the fresh air flow and the exhaust air flow to be guided straight through the membrane stack, where they intersect within the membrane stack. This embodiment also achieves the end plate being located on the side of the membrane stack, i.e., on the end face where the inlet and outlet ports are not located. This facilitates the realization of a seal at the end plate.

[0023] In yet another embodiment, each end plate can have two end regions on opposite sides of the block height. Each end plate is supported on its respective end side by two elastic seals preloaded in the longitudinal direction of the block. The seals are located on one of the end regions of each end plate and extend along the transverse direction of the block. In particular, the seals can extend from one seal frame to the other. This configuration provides a relatively large surface area for receiving fresh or exhaust air between each end plate and the associated end side, which increases the efficiency of the air humidifier.

[0024] In a preferred embodiment, one sealing frame can be arranged on the fresh air inlet side, while the other sealing frame is arranged on the exhaust air outlet side in the first embodiment and on the fresh air outlet side in the second embodiment. This results in a particularly easy-to-implement design of the air humidifier. At the same time, this allows for a configuration in which the preloaded sealing elements arranged between each end plate and the associated end face can extend from one sealing frame to the other sealing frame in the block transverse direction. This ensures a perfect seal in each end region.

[0025] The membranes in the membrane stack are stacked in the longitudinal direction of the block. In other words, the stacking direction in which the membranes in the membrane stack are stacked preferably extends parallel to the longitudinal direction of the block. In particular, the stacking direction may define the longitudinal direction of the block. The membranes form pockets or chambers, i.e., fresh air chambers through which fresh air flows and exhaust air chambers through which exhaust air flows. The fresh air chambers and exhaust air chambers alternate in the stacking direction, so that the fresh air streams and exhaust air streams overlap each other over a large area within the membrane stack but do not mix with each other.

[0026] The membrane stack may be shaped like a rectangular parallelepiped, which facilitates the production of the membrane stack. In this case, the longitudinal dimension of the block may be sized larger than the transverse dimension of the block and may be sized larger than the height dimension of the block. In particular, the transverse dimension and the height dimension of the block may be sized equally.

[0027] In yet another advantageous embodiment, each end plate can have at least one protruding, particularly straight, rib on its outer side facing away from the membrane stack, extending perpendicular to the longitudinal direction of the block, particularly parallel to the transverse direction of the block, and supported by the housing. In this way, forces acting on each 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 accompanying description of the drawings.

[0029] Of course, the features mentioned above and those that may be further described below can be used not only in the combinations respectively described, but also in other combinations or alone, without departing from the scope of the invention as defined by the claims. The elements mentioned above and those that may be further described below of a separately referred to superordinate unit, e.g., apparatus, device or assembly, may form separate constituent parts or components of this unit or may be an integral region or division of this unit, even if not so shown in the drawings.

[0030] A preferred embodiment of the invention is illustrated in the drawings and will be explained in detail in the following description, in which the same reference numerals refer to the same or similar components or components that are the same in terms of function. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is an isometric view of an air humidifier. [Figure 2] FIG. 1 is an isometric cross-sectional view of an air humidifier. [Figure 3] FIG. 1 is an isometric longitudinal section view of an air humidifier. [Figure 4] FIG. 1 is an isometric view of an air humidifier with a transparently depicted housing. [Figure 5] FIG. 10 is an isometric view of the end plate area of ​​the humidifier block in an unloaded state. [Figure 6] FIG. 6 is an isometric view of the area of ​​FIG. 5 under load. [Figure 7] FIG. 10 is a longitudinal section through an area of ​​an end plate of a humidifier block in an unloaded state. [Figure 8] FIG. 8 is a longitudinal section through the area of ​​FIG. 7 under load. [Figure 9] FIG. 10 is an isometric view of an area of ​​an end plate in another embodiment of a humidifier block. [Figure 10] 10 is an isometric view similar to FIG. 1 showing an air humidifier according to another embodiment. [Figure 11] 3 is an isometric cross-sectional view similar to FIG. 2 showing an air humidifier according to another embodiment. [Figure 12] 4 is an isometric longitudinal section view similar to FIG. 3 showing an air humidifier according to another embodiment. [Figure 13] 5 is an isometric view similar to FIG. 4, showing an air humidifier according to another embodiment.

[0032] As shown in Figures 1 to 4 and 10 to 13, air humidifier 1 includes a housing 2 and a humidifier block 3 disposed within the housing 2. The humidifier block 3 cannot be seen in Figure 1. In Figures 4 and 10, the housing 2 is depicted as transparent. In Figures 1 to 4 and 10 to 13, arrows indicate a fresh air flow 4 and a waste air flow 5 that flow through the housing 2 and the humidifier block 3 during operation of the air humidifier 1. The fresh air flow 4 supplies dry fresh air' to the air humidifier 1 and discharges humidified fresh air 4'' from the air humidifier 1. The waste air flow 5 supplies humidified waste air 5' to the air humidifier 1 and discharges dehumidified waste air 5'' from the air humidifier 1. The air humidifier 1 is used to humidify dry fresh air 4' using the humidified waste air 5', and for this purpose may be used particularly in a fuel cell system. For example, the air humidifier 1 can use cathode exhaust air to humidify cathode fresh air in a fuel cell system.

[0033] The housing 2 surrounds the housing interior chamber 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'', a waste air inlet 9 for supplying moist waste air 5', and a waste air outlet 10 for discharging dehumidified waste air 5''.

[0034] The humidifier block 3 is inserted into the housing interior 6 and contains a membrane stack 11. The membrane stack 11 is passable by the fresh air flow 4 and the exhaust air flow 5 and is formed by a plurality of membranes 12. The membranes 12 consist of a membrane material that is impermeable to air and permeable to moisture. The membrane stack 11 is configured in this case as a rectangular parallelepiped, so that the humidifier block 3 defines a block longitudinal direction X, a block transverse direction Y, and a block height direction Z, which extend perpendicularly to one another. Within the membrane stack 11, the membranes 12 can be stacked on top of one another in a stacking direction S. The stacking direction S preferably extends parallel to the block longitudinal direction X. In this case, the stacking direction S can particularly define the block longitudinal direction X.

[0035] As shown in Figures 3 to 9, 12 and 13, the membrane stack 11 has two end sides 13 that are located opposite each other in the block longitudinal direction X or that are located back to back in the block longitudinal direction X. The humidifier block 3 has two end plates 14, each corresponding to one of the end sides 13 and arranged on one of the end sides 13. Each end plate 14 is supported on its corresponding end side 13 via at least one sealing element 15. Each sealing element 15 is elastically configured and elastically preloaded in the block longitudinal direction X. In the embodiment shown here, two such sealing elements 15 are provided on each end plate 14. In particular, these sealing elements extend parallel to the block transverse direction Y and are spaced apart from each other on each end plate 14 in the block height direction Z.

[0036] Each end plate 14 is in contact with the associated end side 13 via a respective sealing element 15. In other locations, each end plate 14 is positioned at a distance from the associated end side 13. As shown in Figures 7 to 9, this results in a cavity 16, which can be used to supply fresh air or waste air. Accordingly, the fresh air flow 4 or waste air flow 5 flows through the cavity 16 during operation of the air humidifier 1.

[0037] During operation of the air humidifier 1, a pressure difference Δp can form within the housing 2 between the fresh air flow 4 and the exhaust air flow 5. This pressure difference Δp can cause elastic deformation, particularly expansion or contraction, of each end plate 14, as shown in FIGS. 6 and 8. As shown in FIGS. 5 to 8, each end plate 14 has a distance 17 from each end side 13 in the longitudinal direction X of the block. This distance 17 exists when no pressure difference Δp is present and increases or decreases when a pressure difference Δp is applied. FIGS. 6 and 8 show an expansion deformation of the end plate 14, which causes the end plate 14 to bend outward, resulting in an increased distance 17'. Alternatively, a contraction deformation of the end plate 14 occurs, which causes the end plate 14 to bend inward. This results in a decreased distance 17'', but this distance 17'' is not shown here. The maximum increase or decrease in the spacing 17 occurs in the middle section of the end plate 14 in the transverse block direction Y. Accordingly, when a pressure differential Δp is applied, the spacing 17 becomes larger or smaller by a predetermined expansion or contraction amount (not shown in detail) than when the pressure differential Δp is not present. In other words, the expansion or contraction amount represents the difference between the increased spacing 17' or decreased spacing 17" that occurs when the pressure differential Δp is applied and the spacing 17 that occurs when the pressure differential Δp is not present. The increased spacing 17' and the decreased spacing 17" are not necessarily quantitatively the same in this case.

[0038] The seals 15 are designed so that in their fully relaxed, i.e., particularly removed, state (not shown here), they are preloaded in the longitudinal direction X of the block by a predetermined amount (not shown in detail) greater than in the preloaded installed state, as shown, for example, in FIGS. 5 and 7 . In this installed state, the seals 15 fill the gap 17 between each end plate 14 and the associated end face 13 in the absence of a pressure differential Δp. The preload of the seals is then expediently greater than the elongation of each end plate 14. In other words, due to their elasticity, the seals 15 can expand themselves in the longitudinal direction X of the block by a larger amount than the maximum expected increase in the gap 17 resulting from the deformation of the end plate 14 due to the pressure differential Δp. This ensures that the correspondingly increased gap 17 or 17' can still be reliably filled by the seals 15 even in the event of the maximum expected deformation of the end plate 14. FIG. 6 clearly shows that the elasticity of the sealing member 15 ensures that the gap 17 which varies along the transverse direction Y of the block can be filled.

[0039] As can be seen from the example of Figures 3 to 8, the sealing elements 15 may be configured as I-shaped sealing elements. Such I-shaped sealing elements have an elongated cross section, the longitudinal direction of which is oriented parallel to the direction of action of the sealing elements 15. In the example shown here, the sealing elements 15 act in the block longitudinal direction X, and therefore the longitudinal direction of the sealing elements 15 is oriented parallel to the block longitudinal direction X. This achieves that each sealing element 15 can be compressed in order to obtain a preload of the sealing elements 15 in the block longitudinal direction X.

[0040] In contrast to this embodiment, in the embodiment shown in FIG. 9, the sealing element 15 is configured as a lip seal. The lip seal has a retaining base 18 and a sealing contour 19. In the example shown in FIG. 9, the retaining base 18 is secured to the respective end plate 14. For example, the retaining base 18 can be inserted into a receiving groove 20 for this purpose. The receiving groove 20 is formed for this purpose on the inner side of the end plate 14 facing the associated end side 13. The sealing contour 19 contacts the end side 13. Alternatively, the retaining base 18 can be secured to the end side 13, in which case the sealing contour 19 contacts the end plate 14. However, the illustrated configuration is preferred. In this case, the preload of the sealing element 15 in the block longitudinal direction X is achieved by elastically bending the sealing element 15 about a bending axis 21 extending perpendicular to the block longitudinal direction X. In the example shown in FIG. 9, the bending axis 21 extends parallel to the block transverse direction Y. Furthermore, in the embodiment shown in Fig. 9, the sealing element 15 is arranged in such a way that the pressure difference Δp that occurs between the fresh air flow 4 and the exhaust air flow 5 during operation of the air humidifier 1 increases or decreases the preloaded contact of the sealing element 15 against the end side 13. For example, as shown in Fig. 9, the pressure difference Δp can preferably be applied to the sealing element 15 in such a way that an overpressure is generated in the cavity 16. This presses the sealing contour 19 against the end side 13.

[0041] In the embodiment shown in Fig. 9, the sealing element 15 may be bonded to the end plate 14 in the region of the retaining base 18. However, such bonding is optional. In contrast, in the region of the sealing contour 19, the sealing element 15 is in loose contact with the end face 13.

[0042] 3 to 8, 12 and 13, it may be provided that the sealing element 15 is held by the end plate 14, in particular glued to the end plate 14, and is in loose contact with the end side 13. Similarly, the opposite configuration is also conceivable, i.e., the sealing element 15 is held by the end side 13, in particular glued to the end side 13, while the sealing element 15 is in loose contact with the end plate 14. It is also conceivable that the sealing element 15 is held by both the end plate 14 and the end side 13, or glued to both the end plate 14 and the end side 13.

[0043] As shown in Figures 2 to 4 and 11 to 13, the membrane stack 11 has two sides 22, 23 positioned back to back in a direction perpendicular to the block longitudinal direction X. In the example shown here, the sides 22, 23 are positioned back to back in the block transverse direction Y. The humidifier block 3 has one seal frame 24 on each of these sides 22, 23. Each seal frame 24 is arranged on the edge of each side 22, 23 in a closed ring shape. Each seal frame 24 tightly supports the humidifier block 11 on each side 22, 23 to the housing 2. The embodiment shown here further specifies that each seal frame 24 is configured to surround both end plates 14 on each side 22, 23. As a result, each seal frame 24 extends annularly on the outside along the periphery of the humidifier block 3, in this case extending along the end plates 14 on the outside. The annular extension direction of the seal frame 24 is in this case annularly extending about an axis extending parallel to the transverse direction Y of the block.

[0044] 2 and 4, and 11 and 13, each seal frame 24 may have an annular side seal portion 25. Each seal frame 24 is tightly supported on the housing 2 via each side seal portion 25.

[0045] 2-4 and 11-13, membrane stack 11 has a new air inlet side 26 fluidly connected to new air inlet 7, a new air outlet side 27 fluidly connected to new air outlet 8, an exhaust air inlet side 28 fluidly connected to exhaust air inlet 9, and an exhaust air outlet side 29 fluidly connected to exhaust air outlet 10. Within membrane stack 11, as shown in FIGS. 2 and 11, a new air channel 30 fluidly connecting new air inlet side 26 to new air outlet side 27 and an exhaust air channel 31 fluidly connecting exhaust air inlet side 28 to exhaust air outlet side 29 are formed.

[0046] 1 to 4, the fresh air inlet side 26 and the exhaust air outlet side 29 are located on opposite sides in the block transverse direction Y. The exhaust air inlet side 28 and the fresh air outlet side 27 are located on opposite sides in the block height direction Z. In the illustrated embodiment, the two seal frames 24 are thus located on the fresh air inlet side 26 and the exhaust air outlet side 29, so that the fresh air inlet side 26 and the exhaust air outlet side 29 form the above-mentioned sides 22, 23 located on opposite sides in a direction perpendicular to the block longitudinal direction X.

[0047] In contrast to this embodiment, in the other or second embodiment shown in Figures 10 to 13, the fresh air inlet side 26 and the fresh air outlet side 27 are located on opposite sides in the block transverse direction Y. The exhaust air inlet side 28 and the exhaust air outlet side 29 are located on opposite sides in the block height direction Z. As a result, in the other embodiment shown here, both seal frames 24 are located on the fresh air inlet side 26 and the fresh air outlet side 27, so that the fresh air inlet side 26 and the fresh air outlet side 27 form the above-mentioned sides 22, 23 located on opposite sides in the direction perpendicular to the block longitudinal direction X.

[0048] As can be seen particularly in Figures 3 and 12, each end plate 14 has two end regions 32, 33 on opposite sides in the block height direction Z. Figures 3 and 12 show that each end plate 14 has an upper end region 32 and a lower end region 33. Each end plate 14 is supported on its associated end side 13 via two sealing elements 15 of the type described above, each of which is elastically preloaded in the block longitudinal direction X. The two sealing elements 15 are arranged in each end plate 14 at one end region of the two end regions 32, 33 and are configured so that the sealing elements 15 extend along the block transverse direction Y. Furthermore, the sealing elements 15 preferably extend continuously from one sealing frame 24 to the other sealing frame 24 in the block transverse direction Y. The cavity 16 formed by the two sealing elements 15 in the longitudinal direction X of the block between each end plate 14 and the associated end side 13 is thereby delimited in the height direction Z of the block.

[0049] As shown in Figures 3, 4, 12, and 13, each end plate 14 may have at least one protruding rib 34 extending perpendicular to the block longitudinal direction X on the outer side opposite the membrane stack 11. Each end plate 14 is supported on the housing 2 via this rib 34. In these examples, each rib 34 extends straight and parallel to the block transverse direction Y. In this case, each rib 34 may be embedded in the seal frame 24. For example, the seal frame 24 may be integrally injection molded or foam molded with the membrane stack 11 and both end plates 14.

Claims

1. An air humidifier (1) for humidifying dry fresh air (4') using moist exhaust air (5'), in particular of a fuel cell system, comprising: a housing (2) surrounding a housing interior (6) and having a fresh air inlet (7) for supplying dry fresh air (4'), a fresh air outlet (8) for discharging humidified fresh air (4''), a waste air inlet (9) for supplying humid waste air (5'), and a waste air outlet (10) for discharging dehumidified waste air (5''); a humidifier block (3) inserted in the housing interior (6) and having a membrane stack (11) formed by a plurality of membranes (12) that are impermeable to air and permeable to moisture and that are passable by the fresh air flow (4) and the exhaust air flow (5) for humidifying the dry fresh air (4') with the humid exhaust air (5'); Equipped with The membrane stack (11) has two end faces (13) located opposite each other in the block longitudinal direction (X), The humidifier block (3) has two end plates (14), each of which is disposed on one of the end faces (13); Each of the end plates (14) is supported on each of the end faces (13) via at least one elastic sealing member (15) preloaded in the block longitudinal direction (X). Air humidifier (1).

2. During operation of the air humidifier (1), a pressure difference (Δp) is created in the housing (2) between the fresh air flow (4) and the exhaust air flow (5), Each of the end plates (14) has a distance (17) from each of the end face sides (13) in the block longitudinal direction (X), and when a differential pressure (Δp) is applied, the distance (17) in the block longitudinal direction (X) becomes larger by a predetermined amount of elongation or smaller by a predetermined amount of contraction than when no differential pressure (Δp) is present; Each of the sealing elements (15) is configured such that in a relaxed state, the preload of the sealing element (15) is greater in the block longitudinal direction (X) than in a preloaded assembled state, and in the preloaded assembled state, the sealing element (15) fills the gap (17) between each of the end plates (14) and each of the end faces (13) in the absence of a pressure differential (Δp), Each of the seal members (15) is further configured such that the amount of preload of the seal member (15) is greater than the amount of extension of each of the end plates (14).

2. Air humidifier (1) according to claim 1, characterized in that it

3. each said sealing element (15) is configured as an I-shaped sealing element, which has an elongated cross section oriented with respect to its longitudinal direction parallel to the block longitudinal direction (X); Each of the seal members (15) is compressed in the block longitudinal direction (X), thereby applying a preload to each of the seal members (15) in the block longitudinal direction (X).

3. Air humidifier (1) according to claim 1 or 2, characterized in that it comprises:

4. Each of the sealing members (15) is configured as a lip seal member, and the lip seal member has a holding base (18) held on each of the end plates (14) or each of the end face sides (13), and a sealing contour (19) in contact with each of the end face sides (13) or each of the end plates (14), Each of the seal members (15) is elastically bent and deformed about a bending axis (21) extending in a direction perpendicular to the block longitudinal direction (X), so that each of the seal members (15) is preloaded in the block longitudinal direction (X).

3. Air humidifier (1) according to claim 1 or 2, characterized in that it comprises:

5. each said sealing element (15) is arranged in such a way that a pressure difference (Δp) between the fresh air flow (4) and the exhaust air flow (5) increases or decreases the preloaded contact of each said sealing element (15) with each said end side (13) or each said end plate (14); 5. Air humidifier (1) according to claim 4, characterized in that it

6. Each of the seal members (15) is bonded to each of the end plates (14) and each of the end face sides (13). Air humidifier (1) according to any one of claims 1 to 5, characterized in that it comprises:

7. Each of the sealing members (15) is held by or adhered to each of the end plates (14) and loosely contacts each of the end faces (13), or Each of the sealing members (15) is held by or adhered to each of the end faces (13) and is in loose contact with each of the end plates (14). Air humidifier (1) according to any one of claims 1 to 5, characterized in that it comprises:

8. The membrane stack (11) has two sides (22, 23) positioned back to back in a direction perpendicular to the longitudinal direction (X) of the block, The humidifier block (3) has a seal frame (24) on each of the two sides (22, 23), the seal frame (24) being arranged in an annular shape with its edge closed on each side (22, 23) to tightly support the humidifier block (3) in the housing (2); Each of the seal frames (24) also surrounds the end plates (14) on each of the sides (22, 23). Air humidifier (1) according to any one of claims 1 to 7, characterized in that it comprises:

9. Each of the seal frames (24) has an annular side seal portion (25), and each of the seal frames (24) is tightly supported on the housing (2) via the side seal portion (25). Air humidifier (1) according to claim 8, characterized in that it

10. 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 air inlet side (28) fluidly connected to the exhaust air inlet (9), and an exhaust air outlet side (29) fluidly connected to the exhaust air outlet (10), A new air channel (30) fluidly connecting the new air inlet side (26) to the new air outlet side (27) and an exhaust air channel (31) fluidly connecting the exhaust air inlet side (28) to the exhaust air outlet side (29) are formed in the membrane stack (11), The new air inlet side (26) and the new air outlet side (27) are located on opposite sides to each other in a block lateral direction (Y) extending in a direction perpendicular to the block longitudinal direction (X), and the exhaust air inlet side (28) and the exhaust air outlet side (29) are located on opposite sides to each other in a block height direction (Z) extending in a direction perpendicular to the block longitudinal direction (X) and perpendicular to the block lateral direction (Y). Air humidifier (1) according to any one of claims 1 to 9, characterized in that it

11. Each of the end plates (14) has two end regions (32, 33) on opposite sides in the block height direction (Z), Each of the end plates (32, 33) is supported on each of the end face sides (13) via two elastic sealing members (15) that are preloaded in the block longitudinal direction (X), The two sealing members (15) are arranged in one of the two end regions (32, 33) of each of the end plates (14) and extend along the block transverse direction (Y). Air humidifier (1) according to claim 10, characterized in that it

12. One of the seal frames (24) is disposed on the new air inlet side (26), and the other seal frame (24) is disposed on the new air outlet side (27). Air humidifier (1) according to claim 10 or 11 and claim 8 or 9, characterized in that

13. The membranes (12) in the membrane stack (11) are stacked in the block longitudinal direction (X). Air humidifier (1) according to any one of claims 1 to 12, characterized in that it

14. The membrane stack (11) is configured in the shape of a rectangular parallelepiped. Air humidifier (1) according to any one of claims 1 to 13, characterized in that it

15. Each of the end plates (14) has at least one protruding rib (34) on the outer side opposite the membrane stack (11), extending perpendicular to the block longitudinal direction (X) or parallel to the block transverse direction (Y), the rib (34) being supported by the housing (2). Air humidifier (1) according to any one of claims 1 to 14, characterized in that it

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