Ion exchange filter assembly

Abstract

An ion exchange filter arrangement (10) comprising: a housing suitable for receiving a coolant (12); a container area (22) for an ion exchange filter (32) which is defined within the housing (12) and is suitable for accommodating an ion exchange filter (32), wherein the ion exchange filter container area (22) forms a first coolant flow path (F1) within the housing (12); and with a bypass line (24) for coolant, which is defined within the housing (12) and forms a second coolant flow path (F2) in a flow arrangement parallel to the first coolant flow path (F1), wherein the second coolant flow path (F2) surrounds the first coolant flow path (F1) and is concentric to the first coolant flow path (F1), further comprising an annular wall (44) which is arranged inside the housing (12) and defines the ion exchanger filter vessel area (22) and the bypass line (24) for the coolant, wherein the ion exchange filter arrangement (10) defines a coolant inlet (56) and a coolant outlet (28) with first (F1) and second coolant flow paths (F2), each path extending from the coolant inlet (56) to the coolant outlet (28) and the annular wall (44) extending longitudinally between the coolant inlet (56) and the coolant outlet (28) to separate the first (F1) and second coolant flow paths (F2) from each other, and wherein the inlets of the first (F1) and second coolant flow paths (F2) communicate with each other at the coolant inlet (56) and outlets of the first (F1) and second coolant flow paths (F2) communicate with each other at the coolant outlet (28), wherein an ion exchange filter (32) is arranged in the ion exchange filter container area (22) of the housing (12), wherein the coolant bypass line (24) is defined at a location radially between an outer side of the annular wall (44) and an inner side of the housing (12), further comprising a container tube (34) defining a coolant inlet and a coolant outlet (52) and having the ion exchange filter (32) attached therein, wherein the container tube (34) contains the annular wall (44) and the bypass line (24) contains a bypass line inlet (54) defined radially from the annular wall (44) and communicating with the coolant inlet (56), wherein the first coolant flow path (F1) defines a first outlet and the second coolant flow path (F2) defines a second outlet near the first outlet, the first and second outlets communicating with each other at the outlet (28) of the casing (12), the second coolant flow path (F2) being capable of generating a localized low-pressure region in the coolant as the coolant from the second flow path (F2) flows past the first outlet, the outlet of the container tube (34) comprising an annular projection (62) extending longitudinally outward from a base region (64) of the container tube (34).

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority over preliminary US application No. 61 / 594,720, filed on February 3, 2012. The full disclosure of the aforementioned application is incorporated by reference into this application. AREA

[0002] The present invention relates to ion exchange filter arrangements. BACKGROUND

[0003] This section provides background information relating to the present invention and does not necessarily represent the prior art.

[0004] Ion exchange filter systems can be included in cooling systems to remove ions from the coolant and prevent short circuits. External bypass loops and filters can be included in the system to limit pressure drop across the ion exchange filter system and to remove suspended particles from the system.

[0005] From EP 2 767 514 A1, an ion exchanger is known which is configured to remove a contaminating ion from a coolant used to cool a fuel cell. The ion exchanger comprises an inlet section with an inlet path into which the coolant enters; an outlet section with an outlet path for discharging the coolant; and an outer casing with an upstream end where the inlet section is located and a downstream end where the outlet section is located.The ion exchanger further comprises an inner housing located inside the outer housing; an outer channel formed between the inner and outer housings to connect the inlet and outlet channels; and an inner channel formed within the inner housing to connect the inlet and outlet channels and configured to contain an ion exchange resin capable of removing a coolant. The inner housing has a through-hole that connects the inner and outer channels.

[0006] Further relevant state of the art includes DE 10 2012 001 194 A1, US 2005 / 0 115 884 A1, JP 2009 / 219 954 A, US 2011 / 0 233 153 A1 and DE 603 ​​11 088 T2. REVELATION OF THE INVENTION

[0007] This section provides a general summary of the invention and is not a comprehensive disclosure of the entire scope or all of its features.

[0008] The ion exchange filter assembly can include a housing suitable for receiving coolant; a vessel area for the ion exchange filter, defined within the housing and suitable for receiving an ion exchange filter; and a coolant bypass line, defined within the housing. The vessel area for the ion exchange filter can form a first coolant flow path within the housing, and the coolant bypass line can form a second coolant flow path in a flow arrangement parallel to the first coolant flow path.

[0009] An ion exchange filter assembly can include a housing suitable for holding coolant; an ion exchange filter arranged within the housing; and a coolant bypass line defined within the housing outside the ion exchange filter. A first flow path for the coolant is defined by the ion exchange filter, and a second flow path for the coolant, in a flow arrangement parallel to the first coolant flow path, is formed by the coolant bypass line.

[0010] Further applications will become apparent from the description given here. The description and specific examples in this summary are intended solely for illustrative purposes and not to limit the scope of protection of the present invention. FIGURES

[0011] The drawings described herein serve only to illustrate selected embodiments and not all possible embodiments, and are not intended to limit the scope of protection of the present invention. Fig. Figure 1 is a perspective view of an ion exchange filter arrangement according to the present invention; Fig. Figure 2 is a perspective exploded view of the in Fig. 1 shown ion exchange filter arrangement; Fig. Figure 3 is a cross-sectional view of the ion exchange filter arrangement according to Fig. 1 with a schematically illustrated ion exchanger filter; Fig. Figure 4 is a top view of a section of an ion exchange filter cartridge of the in Fig. 1 shown ion exchange filter arrangement; Fig. Figure 5 is a schematic, fragmentary cross-sectional representation of the ion exchange filter of the in Fig. 1 shown ion exchange filter arrangement; Fig. 6 is a schematic, perspective exploded view of first and second layers, which shows the in Fig. The 5 ion exchange filters shown form; Fig. Figure 7 is a schematic, perspective exploded view showing an alternative second layer for the ion exchange filter according to the present invention; and Fig. Figure 8 is a schematic representation of a vehicle fuel cell system with the ion exchange filter arrangement according to Fig. 1.

[0012] Corresponding reference symbols denote corresponding parts in all different views of the figures. DETAILED DESCRIPTION

[0013] Exemplary embodiments will now be described in more detail with reference to the attached figures.

[0014] Exemplary embodiments are presented so that this disclosure is comprehensive and fully conveys the scope of protection to those skilled in the art. Numerous specific details are given, such as examples of specific components, devices, and methods, to enable a precise understanding of the exemplary embodiments of the present invention. It is clear to those skilled in the art that specific details need not be used, that the exemplary embodiments can be implemented in many different ways, and that these should not be understood as limiting the scope of protection of the invention. In some exemplary embodiments, known methods, known device structures, and known technologies are not described in detail.

[0015] The terminology used herein serves only to describe specific exemplary embodiments and is not intended to be restrictive. The singular forms "ein," "eine," and "der," "die," "das" used here may also include the plural forms unless the context clearly indicates otherwise. The terms "contain," "containing," "comprising," and "exhibiting" are inclusive and therefore specify the presence of the named features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.The procedural steps, processes, and operations described herein are not to be understood as necessarily requiring their execution in the specific order described or depicted, unless a specific order of execution is explicitly stated. It is also understood that additional or alternative steps may be performed.

[0016] When an element or layer is described as "on," "interacting with," "connected with," or "coupled to" another element or layer, it may be directly on, interacting with, connected with, or coupled to that other element or layer, or there may be intervening elements or layers. In contrast, when an element is described as "directly upon," "directly interacting with," "directly connected with," or "directly coupled to" another element or layer, then there are no intervening elements or layers. Other words used in describing the relationship between elements should be interpreted in the same way (e.g., "between" as opposed to "directly between," "adjacent" as opposed to "directly adjacent," etc.). The term "and / or," as used herein, includes any and all combinations of one or more of the associated parts listed.

[0017] Although the terms first, second, third, etc., may be used herein to describe different elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be restricted to these terms. These terms are used only to distinguish one element, component, region, layer, or section from other regions, layers, or sections. Terms such as "first," "second," and other numerical terms used herein do not imply any sequence or order unless clearly evident from the context. Therefore, a first element, component, region, layer, or section, as described below, could be designated as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0018] Spatial terms, such as "within," "outside," "below," "under," "lower," "above," "upper," and similar terms, may be used herein to simplify the description and to describe the relationship of one element or feature to other element(s) or feature(s), as illustrated in the figures. Spatial terms may also be used to encompass different orientations of the device during use or operation, in addition to the orientation shown in the figures. For example, if the device is upside down in the figures, elements that would be described as "below" or "below" other elements or features will then be oriented "above" the other elements or features. Therefore, the example term "below" can encompass both an orientation above and below.The device could also be oriented differently (rotated by 90° or other orientations) and the spatially relative descriptions used herein are then interpreted accordingly.

[0019] As in the Fig. As shown in Figures 1-3, an ion exchange filter assembly 10 can comprise a housing 12, an ion exchange filter cartridge 14, and a mounting mechanism 16. The housing 12 can have a generally cylindrical body with first and second ends 18, 20, with an ion exchange filter reservoir area 22 and a coolant bypass line 24 defined within the housing 12 between the first and second ends 18, 20. The first end can define an opening 26 for receiving the ion exchange filter cartridge 14, and the second end 20 can define a coolant outlet 28 for the ion exchange filter assembly 10.

[0020] The ion exchange filter cartridge 14 comprises a container tube assembly 30 and an ion exchange filter 32, which is mounted within the container tube assembly 30. The container tube assembly 30 may include a container tube 34, an end cap 36, a seal 38, particle separation filters 40, and sieves 42. The ion exchange filter cartridge 14 can be made of a variety of polymers that have a low total organic carbon (TOC) release value during operation in order to maintain the coolant conductivity within a desired range. The container tube 34 defines an annular wall 44 with first and second ends 46, 48 in the longitudinal direction. The first end 46 in the longitudinal direction can define an opening 50 that accommodates the ion exchange filter 32, and the second end 48 in the longitudinal direction can define an outlet opening 52 of the ion exchange filter cartridge 14.Bypass inlets 54 for coolant are provided radially through this annular wall 44 and can form part of the bypass line 24 for coolant.

[0021] The particle separation filters 40 can be arranged within the housing 12 and can be in fluidic communication with the coolant flow at a location upstream of the coolant outlet 28. In the present non-limiting example, the particle separation filters 40 are fixed to the ion exchange filter cartridge 14, with one particle separation filter 40 being arranged at the outlet opening 52 and the bypass inlet 54 for coolant. More precisely, the particle separation filters 40 can be formed integrally with the container tube 34 by means of an overmolding process. Although described above as part of an ion exchange filter cartridge 14, it is clear that the present invention is not limited to such arrangements. Instead, one or more particle separation filters 40 can be arranged within the housing 12 outside the ion exchange filter cartridge 14.

[0022] The end cap 36 can be fixed to the longitudinally first end 46 and can define a coolant inlet 56 for the ion exchange filter assembly 10. The coolant inlet 56 communicates with the ion exchange filter vessel area 22 and also communicates with the coolant bypass line 24 via the coolant bypass inlets 54. The end cap 36 can be attached to the vessel tube 34 in many different ways, including, but not limited to, welding. Reinforcing or supporting elements 58, 60 can be included in the coolant inlet 56 and the coolant outlet 28, respectively. The seal 38 can be attached to the end cap 36, and the fastening mechanism 16 can engage with the housing 12, the end cap 36, and the seal 38 to ensure a sealed coolant flow path from the coolant inlet 56 to the coolant outlet 28.More precisely, the fastening mechanism 16 can have the form of a retaining ring that engages with the housing 12 in a threaded manner.

[0023] The ion exchange filter assembly 10 forms a first coolant flow path (F1) within the housing 12 through the ion exchange filter vessel area 22, and more specifically through the ion exchange filter 32, and it forms a second coolant flow path (F2) within the housing 12 through the coolant bypass line 24, parallel to the first coolant flow path (F1). The first and second coolant flow paths (F1, F2) each extend from the coolant inlet 56 to the coolant outlet 58. The annular wall 44 extends longitudinally between the coolant inlet 56 and the coolant outlet 28 to separate the first and second coolant flow paths (F1, F2) from each other. The first coolant flow path (F1) can define a first inlet in communication with a second inlet formed by the second coolant flow path (F2) at coolant inlet 56.The first coolant flow path (F1) can define a first outlet in communication with a second outlet, specifically via the second coolant flow path (F2) at the coolant outlet 28. The second coolant flow path (F2) can surround the first coolant flow path (F1) and can be concentric with the first coolant flow path (F1). The coolant bypass inlets 54 can form a passive flow control mechanism that meters the coolant flow through the first and second coolant flow paths (F1, F2). The coolant bypass inlet can, for example, be dimensioned to meter the coolant bypass flow, and / or the particle separator 40 can be designed to limit, restrict, or meter the coolant bypass flow to a desired percentage of the total coolant flow.

[0024] In the present non-limiting example, the ion exchange filter cartridge 14 is arranged within the ion exchange filter vessel area 22 and cooperates with the housing 12 to form the coolant bypass line 24. More precisely, the annular wall 44 separates and defines at least partially the ion exchange filter vessel area 22 and the coolant bypass line 24. Although the ion exchange filter vessel area 22 and the coolant bypass line 24 have been described as being at least partially delimited by the ion exchange filter vessel, it is obvious that the present invention is not limited to these arrangements. A multitude of alternative arrangements are within the scope of protection of the present invention, including, but not limited to, the arrangement in which the annular wall 44 is part of the housing 12.The coolant bypass line 24 can be defined at a location radially between the outside of the annular wall 44 and the inside of the housing 12.

[0025] The first and second outlets formed by the first and second coolant flow paths (F1, F2) can be located in close proximity to each other. The second coolant flow path (F2) creates a localized low-pressure region in the coolant flow when the coolant from the second flow path (F2) bypasses the first outlet, for example, by means of the Venturi effect. In the present example, the outlet of the container tube 34 includes an annular projection 62 that extends longitudinally outward from a base region 64 of the container tube 34. The bypass coolant flow passes over the annular projection 62 and creates a localized low-pressure region at the outlet opening 52 of the ion exchange filter cartridge 14 to assist the intake of the coolant through the ion exchange filter 32.

[0026] With reference to the Fig. Figures 4-6 also show that the ion exchange filter 32 can have an exoskeleton 66 of the ion exchange filter assembly 10 as well as ion exchange resin beads 68. The sieves 42 can be arranged at the ends of the exoskeleton 66 of the ion exchange filter assembly 10 to enclose the ion exchange resin beads 68. The exoskeleton 66 of the ion exchange filter can contain a porous body with a total porosity of at least 50%, and more precisely, a total porosity of at least 75%. The ion exchange filter 32 can define a first set of channels 70, and the ion exchange resin beads 68 can be arranged in this first set of channels 70. The first set of channels 70 can generally extend parallel to a longitudinal axis (L) of the ion exchange filter 32 along a coolant flow direction (D) from an inlet of the ion exchange filter 32 to an outlet of the ion exchange filter 32.

[0027] The exoskeleton 66 of the ion exchange filter 32 can include a first porous layer defining the first set of channels 70 and a second porous layer 74 adjacent to the first porous layer 72. In the present non-restrictive example, the first and second porous layers 72, 74 are formed from a folded open medium of polypropylene spunbond nonwoven fabric. The first and second porous layers 72, 74 can be arranged to lie directly on top of each other and wound up to form the exoskeleton 66 of the ion exchange filter 32. The first and second porous layers 72, 74 can be wound such that little or no slippage occurs between the layers due to frictional engagement resulting from the porous structure of the first and second porous layers 72, 74. The frictional intervention can eliminate the need for a firm bond between the first and second porous layers 72, 74 by means of an adhesive.Although a winding arrangement has been described, it is understood that the present invention is not limited to such arrangements, and a multitude of alternative shapes are possible, including, but not limited to, a stacked layer arrangement. Furthermore, in either a wound or a stacked arrangement, the exoskeleton 66 of the ion exchange filter 32 can be in the form of a cylinder, as shown, or can have a multitude of alternative shapes, including, but not limited to, cylindrical or rectangular shapes.

[0028] In the Fig. In the example shown in 4-6, the second porous layer 74 can define a second set of channels 76, which are generally oriented transversely with respect to the first set of channels 70. However, this is, as also in Fig. Figure 7 should be understood to mean that the present invention is not limited to such arrangements. For example, a generally flat second layer 174 can be used instead of the second porous layer 74. The generally flat second layer 174 can be porous, similar to the second porous layer 74. The in Fig. The first porous layer 172 shown in Figure 7 may generally be similar to the first porous layer 72 and is therefore not described for the sake of simplicity, although it goes without saying that the description of the first porous layer 72 also applies to the first porous layer 172.

[0029] The first porous layer 72 may contain folds that define the first set of channels 70, and the second porous layer 74 may contain folds that define the second set of channels 76. The ratio between the height (H1) of the first layer of channels 70 and the diameter of the ion-exchange resin beads 68 is at least 4:1 and not more than 10:1. Similarly, the ratio between the width (W1) of the first set of channels 70 and the diameter of the ion-exchange resin beads 68 is at least 4:1 and not more than 10:1. The second set of channels 76 can be similar to the first set of channels 70, wherein there is a ratio between the height (H2) of the second set of channels 76 and the diameter of the ion exchange resin beads 68 of at least 4:1 and not more than 10:1, and the ratio between the width (W2) of the second set of channels 76 and the diameter of the ion exchange resin beads 68 is at least 4:1 and not more than 10:1.

[0030] The ion exchange resin beads 68 may contain anode resin beads 78 and cathode resin beads 80. The diameters of the anode and cathode resin beads 78 and 80 may be substantially the same. In this context, the diameter of the anode resin beads 78 should be within 10% of the diameter of the cathode resin beads 80. The anode and cathode resin beads 78 and 80 may contain nuclear-grade mixed-bed resin. The present non-limiting example contains AMBERLITE® IRN170 resin, which is commercially available from Dow Chemical.

[0031] For the sake of simplicity, the assembly process for the ion exchange filter cartridge 14 is described with reference to the first and second porous layers 72, 74, although it is understood that the description also applies to the first porous layer 172 and the second layer 174. The first and second porous layers 72, 74 can be placed on top of each other and then rolled up to form the exoskeleton 66 of the ion exchange filter 32. The exoskeleton 66 of the ion exchange filter 32 can then be placed inside the container tube 34 at the longitudinally first end 46. After the exoskeleton 66 of the ion exchange filter 32 has been arranged inside, ion exchange resin beads 68 can be filled into one end 82 of the exoskeleton 66 of the ion exchange filter 32 at the first longitudinal end 46b of the container tube 34.

[0032] The container tube 34, with the exoskeleton 66 of the ion exchange filter 32 placed within it, can be vibrated both longitudinally and laterally during the filling process with ion exchange resin beads 68. This vibration causes the ion exchange resin beads 68 to migrate into the exoskeleton 66 of the ion exchange filter 32 and fill the first and second sets of channels 70, 76. The use of anode and cathode resin beads 78, 80 with similar diameters can facilitate the incorporation of the beads, keeping them in a mixed state. The sieves 42 can retain the anode and cathode resin beads 78, 80 within the exoskeleton 66 of the ion exchange filter 32. The sieve 42 can be positioned at the end 82 after it has been completely filled with spheres.

[0033] The end cap 36 can then be attached to the longitudinal end 46 of the container tube 34. As indicated above, the end cap 36 can be attached to the container tube 34 by a variety of methods, including, but not limited to, welding. The ion exchange filter cartridge 14 can then be inserted into the housing 12, and the fastening mechanism 16 can then engage with the seal 38 and be attached to the housing 12 to secure the ion exchange filter cartridge 14 within the housing 12 in a sealed arrangement.

[0034] The ion exchange filter cartridge 14 can be a replaceable ion exchange filter cartridge 14. The fastening mechanism 16 can also be designed to be detachable from the housing 12 to allow removal and replacement of the ion exchange filter cartridge 14. Therefore, the housing 12 can remain in the system without the need for replacement while the ion exchange filter cartridge 14 is being renewed.

[0035] The ion exchange filter assembly 10 can be used in a variety of systems, including, but not limited to, vehicle fuel cell cooling systems and cooling systems for electronic components, such as electronic circuits. Fig. Figure 8 illustrates the ion exchange filter assembly 10 as it is inserted into a vehicle fuel cell system 84. The vehicle fuel cell system 84 can include anode and cathode plates 86, 88, and a coolant path 90 defined between the anode and cathode plates 86, 88. A coolant pump 92 can pump coolant through the coolant path 90 and through the ion exchange filter assembly 10. As shown in Fig.As can be seen in Figure 8, the insertion of the coolant bypass line 24 within the housing 12 eliminates the need for an external bypass in the vehicle fuel cell system 84. The integral coolant bypass 24 can also eliminate the need for a bypass line control valve due to the passive flow control mechanism formed by the coolant bypass inlets 54. An external particle separator can likewise be eliminated from the vehicle fuel cell system 84 due to the insertion of the particle separators 40 within the ion exchange filter assembly 10. Furthermore, the size and orientation of the first set of channels 70 can inhibit the migration and separation of the anode and cathode resin beads 78, 80 under vehicle operating conditions that cause vibration of the ion exchange filter assembly 10.The size and orientation of the second set of channels 76 can further suppress the migration and separation of the anode and cathode resin spheres 78, 80.

[0036] The foregoing description of the exemplary embodiments was prepared for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular exemplary embodiment are generally not limited to that specific embodiment, but are, where applicable, interchangeable and may be used in a selected exemplary embodiment, even if that embodiment is not specifically shown or described. This can also be varied in many ways. These variations are not considered deviations from the invention, and all such modifications are intended to be covered by the scope of protection of this invention.

Claims

[1] An ion exchange filter arrangement (10) comprising: a housing suitable for receiving a coolant (12); a container area (22) for an ion exchange filter (32) which is defined within the housing (12) and is suitable for accommodating an ion exchange filter (32), wherein the ion exchange filter container area (22) forms a first coolant flow path (F1) within the housing (12); and with a bypass line (24) for coolant, which is defined within the housing (12) and forms a second coolant flow path (F2) in a flow arrangement parallel to the first coolant flow path (F1), wherein the second coolant flow path (F2) surrounds the first coolant flow path (F1) and is concentric to the first coolant flow path (F1), further comprising an annular wall (44) which is arranged inside the housing (12) and defines the ion exchanger filter vessel area (22) and the bypass line (24) for the coolant, wherein the ion exchange filter arrangement (10) defines a coolant inlet (56) and a coolant outlet (28) with first (F1) and second coolant flow paths (F2), each path extending from the coolant inlet (56) to the coolant outlet (28) and the annular wall (44) extending longitudinally between the coolant inlet (56) and the coolant outlet (28) to separate the first (F1) and second coolant flow paths (F2) from each other, and wherein the inlets of the first (F1) and second coolant flow paths (F2) communicate with each other at the coolant inlet (56) and outlets of the first (F1) and second coolant flow paths (F2) communicate with each other at the coolant outlet (28), wherein an ion exchange filter (32) is arranged in the ion exchange filter container area (22) of the housing (12), wherein the coolant bypass line (24) is defined at a location radially between an outer side of the annular wall (44) and an inner side of the housing (12), further comprising a container tube (34) defining a coolant inlet and a coolant outlet (52) and having the ion exchange filter (32) attached therein, wherein the container tube (34) contains the annular wall (44) and the bypass line (24) contains a bypass line inlet (54) defined radially from the annular wall (44) and communicating with the coolant inlet (56), wherein the first coolant flow path (F1) defines a first outlet and the second coolant flow path (F2) defines a second outlet near the first outlet, the first and second outlets communicating with each other at the outlet (28) of the casing (12), the second coolant flow path (F2) being capable of generating a localized low-pressure region in the coolant as the coolant from the second flow path (F2) flows past the first outlet, the outlet of the container tube (34) comprising an annular projection (62) extending longitudinally outward from a base region (64) of the container tube (34). [2] The ion exchange filter arrangement (10) according to claim 1, wherein the bypass line inlet (54) defines a passive flow control mechanism that meters the coolant flow through the first (F1) and second coolant flow paths (F2). [3] The ion exchange filter arrangement (10) according to claim 1, further comprising a particle separation filter (40) which is arranged inside the housing (12) and communicates with the coolant. [4] The ion exchange filter assembly (10) according to any one of claims 1 to 3, further comprising a fastening mechanism (16) which is detachably attached to the housing (12), wherein the fastening mechanism (16) is designed to secure the ion exchange filter (32) inside the housing (12) when it is engaged with the housing (12) and to allow the removal of the ion exchange filter (32) when it has been detached from the housing (12). [5] The ion exchange filter assembly (10) according to claim 4, further comprising a container tube (34) defining a coolant inlet and a coolant outlet, and the ion exchange filter (32) attached therein, wherein the container tube (34) and the ion exchange filter (32) form a replaceable ion exchange filter cartridge (14) and the fastening mechanism (16) includes a retaining ring which engages with the ion exchange filter cartridge (14) and the housing (12) and releasably holds the ion exchange filter cartridge (14) within the housing (12).

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