Abstract:
A cooling device ( 10 ) for a functional system, in particular a fuel cell system ( 12 ) for a motor vehicle is disclosed. The cooling device ( 10 ) includes a conduit system ( 14, 22 ) for a cooling fluid flow connected to the functional system ( 12 ) for cooling. A container ( 20 ) of the cooling device ( 10 ) for the cooling fluid is fluidically connected to the conduit system ( 14, 22 ). A treatment unit, in particular an ion exchanger ( 24 ), for treating the cooling fluid is fluidically connected to the conduit system ( 14, 22 ). The container ( 20 ) includes a receptacle chamber to receive the treatment unit ( 24 ) and/or an ion exchanger ( 24 ) disposed so as to stand upright in the container ( 20 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a US bypass continuation application of international application No. PCT/EP2010/061808 having an international filing date of Aug. 13, 2010 and designating the United States, the International Application claiming a priority date of Aug. 13, 2009 based on prior filed German patent application No. DE 10 2009 037 080.3 and further claiming a priority date of Oct. 14, 2009 based on prior filed German patent application No. DE 10 2009 049 427.8. The entire contents of the aforesaid international application and the aforesaid German patent applications are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates to a cooling device of a functional system, in particular of a fuel cell system of a motor vehicle filter. Moreover, the invention concerns a treatment unit, in particular an ion exchanger, for treating a cooling fluid of a cooling device of a functional system, in particular of a fuel cell system, in particular of a motor vehicle, that is fluidically connectable with a conduit system of the cooling device for the cooling fluid and with a container for the cooling fluid that is fluidically connected with the conduit system. 
         [0003]    The invention concerns moreover a cooling fluid container, in particular a cooling fluid compensation container, of a cooling device of a functional system, in particular of a fuel cell system of a motor vehicle, that is fluidically connectable with a conduit system for a cooling fluid that is connected for cooling with the functional system, wherein the conduit system is connected fluidically with a treatment unit, in particular an ion exchanger, for treating the cooling fluid. 
         [0004]    Moreover, the invention concerns an ion exchanger cartridge for treating a fluid, in particular a cooling fluid, comprising a cartridge cover and a granular ion exchange medium. 
       BACKGROUND OF THE INVENTION 
       [0005]    It is known in the market to furnish fuel cell systems, internal combustion engines, and other functional systems that generate heat in mobile or stationary use with cooling circuits in order to keep them at an optimal temperature range for ensuring their function. In the cooling circuits, preferably liquid cooling media (i.e., cooling fluids) are circulated, in particular cooling water or mixtures of cooling water and glycol. In the cooling circuits, there are compensation containers for the liquid cooling medium. In order to ensure optimal cooling and service life of all components of the cooling circuit and of the functional system, it is known to treat the cooling medium in the cooling circuit with appropriate additional treatment units. It is known to employ filters and/or ion exchangers in the cooling medium circuit with which the cooling medium in operation can be purified or freed of undesirable ions. In particular in fuel cell systems, it is necessary that the cooling fluid is desalinated because otherwise there is the risk of short-circuiting due to the conductivity of the cooling fluid. 
         [0006]    The treatment units increase however the space that is required for the cooling device, in particular because they should be accessible easily for servicing purposes. These conditions are not easily fulfilled in particular in case of use in motor vehicles where there is only limited mounting space available. JP 2004311347 A1 discloses a cooling system for a fuel cell system in which at the lower end of the cooling fluid compensation container a treatment unit in the form of an ion exchanger is arranged. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an object of the invention to design a cooling device, a treatment unit, a cooling fluid container, and an ion exchanger cartridge of the aforementioned kind that enable a treatment of the fluid in a simple and reliable way, that is optimal for the function of the fluid, in particular optimize the temperature and composition of the fluid, and are constructed as much as possible in a space-saving way. 
         [0008]    This object is solved according to the invention in that the container has a receptacle for the treatment unit. 
         [0009]    According to the invention, the treatment unit is thus integrated into the container in a space-saving way so that the container and the treatment unit together form a closed component. The shape of the container can be adjusted in a simple way to a mounting space that is available. The container with the treatment unit can be mounted at a location that is easily accessible so that the container and the treatment unit, in particular for servicing purposes, are easily accessible. Fluid connectors of the treatment unit are integrated into the container so that the total number of connectors can be reduced; this simplifies mounting. Separate lines from the treatment unit to the conduit system, as conventional in case of cooling devices of the prior art, can be omitted. By reducing the connectors and conduits that are positioned outside of the container, the risk of leakage is also reduced. The container and the treatment unit can be arranged at the cold side of the cooling device, in particular in flow direction of the cooling fluid in front of the functional system, or at the hot side of the cooling device, in particular in flow direction behind the functional system, or can be arranged in a bypass conduit. Advantageously, the cooling device can have a cooling fluid circuit in which the functional system is arranged. The container can also be part of a radiator, in particular a collector, so that the treatment unit is integrated into the radiator. 
         [0010]    In an advantageous embodiment, the container can be a compensation container. The compensation container, frequently present in any case in a cooling device that is embodied as a cooling fluid circuit, can be arranged at the cold side of the cooling device so that the requirements with regard to temperature resistance of the treatment unit can be lowered. The treatment unit can thus be designed in a simpler and less expensive way. 
         [0011]    In a further advantageous embodiment, the container can have a closable opening, in particular spatially on top, through which the treatment unit can be inserted into the interior of the container in particular so as to be exchangeable. In this way, a service-friendly exchange of exchangeable parts of the treatment unit or of the entire treatment unit is possible from above. This is in particular of great advantage when used in a motor vehicle where, as a result of the limited mounting space, for cooling devices known in the art the exchange of exchangeable parts of the treatment unit up to now has been possible only from below. For this purpose, the motor vehicle must be lifted or must be positioned above a pit and a bottom cover must be removed in order to access the exchangeable parts. 
         [0012]    In a further advantageous embodiment, the treatment unit can have an ion exchanger, in particular an ion exchanger cartridge. By means of an ion exchanger in a simple and efficient way preferably by means of salt metathesis, partial desalination or complete desalination, in particular the conductivity of an aqueous coiling fluid can be reduced which is required in particular in case of fuel cell systems. Also, ion exchangers can be used that are suitable for softening aqueous cooling fluid in order to reduce, or prevent entirely, calcium deposits in the cooling device. Ion exchanger cartridges can be simply exchanged. 
         [0013]    Advantageously, the ion exchanger can have a pressing device for compressing a granular ion exchanger medium. As a result of the pressing action, it is prevented that the cooling fluid upon passing through the ion exchanger forms preferred flow passages which would lead to non-uniform loading of the ion exchanger medium and to a shortened service life. The pressing device can preferably comprise a pressure disk that is loaded by a pretensioned spring. The spring can be arranged preferably such that it does not contact the cooling fluid so that corrosion or other type of chemical reaction with the material of the spring is prevented. 
         [0014]    Moreover, advantageously the container and/or the treatment unit can have at least one component, in particular a jacket for the treatment unit that determines flow of the cooling fluid through the treatment unit. In this way it is ensured that the cooling fluid passes through the treatment unit and is appropriately treated. 
         [0015]    In order to prevent that the cooling fluid upon movement of the container will splash back and forth, advantageously baffle devices or splash guard devices can be provided in the container, in particular baffle plates or baffle ribs, for the cooling fluid. This is of great advantage particularly in case of use in motor vehicles in which the container is moved during travel. 
         [0016]    The container, in particular the compensation container, can be located in a bypass conduit that is fluidically connected with a main conduit system for cooling the fuel cell system. For controlling the flow of the cooling fluid through the bypass conduit and the compensation container, a thermovalve can be arranged in the main conduit system. 
         [0017]    The object is further solved according to the invention in that the treatment unit is designed such that it is arranged in an appropriate receptacle of the container. The above described advantages of the cooling device apply likewise to the treatment unit. 
         [0018]    In an advantageous embodiment, the treatment unit can comprise an ion exchanger, in particular an ion exchanger cartridge that comprises a pressing device for compressing a granular ion exchange medium. 
         [0019]    The object is solved according to the invention also in that the cooling fluid container, in particular the cooling fluid compensation container, has a receptacle for integration of the treatment unit and/or an ion exchanger that is arranged upright in the container. The aforementioned advantages of the cooling device apply likewise to the cooling fluid container. 
         [0020]    In this connection, the cooling fluid compensation container for the fuel cell system or the fuel cell device of a motor vehicle can be designed for flow of cooling medium therethrough which is provided for cooling the fuel cell device. The cooling medium compensation container can comprise a treatment unit in the form of an ion exchanger that is arranged upright in the container. 
         [0021]    With this specific positioning of the ion exchanger in the container, an improved accessibility and manipulation can be achieved with respect to installation of the cooling medium compensation container in the fuel cell system and thus also in the vehicle. This is particularly advantageous in particular for mounting purposes, for testing purposes and the like. 
         [0022]    Moreover, with the upright positioning of the ion exchanger unit or the ion exchanger also its functionality with respect to effectiveness of the ion exchange material or ion exchange medium can be improved. Many vulnerable connecting locations between the ion exchanger insert or ion exchanger cartridge and the cooling medium circuit that may cause a leak, can be designed in this respect to be less critical. Moreover, a compact configuration minimized with respect to mounting space can be achieved. In particular, the upright arrangement of the ion exchanger also enables improved purification of the cooling medium with respect to removal of metal ions from the cooling medium. 
         [0023]    The liquid cooling medium of a fuel cell system must be usually as pure as possible, primarily with regard to metal ions because they can poison the PEM (proton exchange membrane) and/or the catalyst layers of the PEM fuel cells. For this purpose, usually an ion exchanger cartridge is integrated into the cooling medium circuit. The ion exchange capacity of the ion exchange material however decreases over time so that the ion exchanger cartridge must be exchanged regularly. For this purpose, it should be arranged at a location that is as easily accessible as possible. By integration of the ion exchanger into the container and moreover by the specific positional orientation the effectiveness of the ion exchange material can be improved. 
         [0024]    With the construction according to the invention, advantageously a longer residence time of the liquid cooling medium in the ion exchanger cartridge can be achieved. In this way, the contact time of the cooling medium with the ion exchanger medium is extended so that the efficiency of the ion exchange is improved. The purification effect is improved thereby so that the cooling medium becomes even more pure. Moreover, the exchangeability of the ion exchanger cartridge is improved significantly. No cooling medium must be drained and the ion exchanger cartridge can be removed in a simple way so that the problem of introduction of harmful contaminants into the cooling circuit can be avoided. With the construction according to the invention of the cooling medium compensation container with the specific positioning of the ion exchanger unit or the ion, this unit can be removed and replaced comfortably and efficiently exchanger without draining the cooling medium and the introduction of contaminants into the cooling circuit can be at least reduced or even avoided as much as possible. 
         [0025]    By the integration and the thus eliminated interfaces, a simpler and more reliable mounting process is provided so that leaks in the cooling system are prevented. A guided locking action of the ion exchanger prevents moreover a possible sliding and ensures full functionality. Especially this type of a specific no-destruction detachable connection in the form of a locking action enables the position-stable attachment while still providing simple separation of the ion exchanger from the cooling medium compensation container. 
         [0026]    In this context, an upright connection of the ion exchanger in the container is understood as positioning such that the longitudinal axis of the ion exchanger is arranged maximally at an angle of 45 degrees relative to the longitudinal axis of the cooling medium compensation container. In particular, and in an especially preferred arrangement, it is provided that the longitudinal axis of the cooling medium compensation container and the longitudinal axis of the ion exchanger are arranged parallel or coaxial so that the ion exchanger is arranged vertically in the cooling medium compensation container. The aforementioned advantages can thus be achieved in a special way. Moreover, with this upright, in particular vertical, arrangement of the ion exchanger, washing out of the ion exchange material can be avoided and in this way the effectiveness of the ion exchanger can be improved. In particular by vertical positioning of the ion exchanger and flow of the cooling medium through the ion exchanger preferably from bottom to top, but optionally also from top to bottom, the residence time and thus the exchange of ions from the cooling medium into the ion exchange material is improved. By reduction of the interfaces and the integration of two components into one component, advantages with respect to mounting, servicing, and maintenance work and weight advantages are provided. Because the locking action of the ion exchanger cartridge it can be mounted quickly and without further securing means and withstands without problems even vehicle-typical vibrations (shaking) without becoming loose or sliding. 
         [0027]    By locking of the insert or cartridge at a defined interface in the compensation container, moreover mounting parts such as screws and hose clamps are no longer needed. 
         [0028]    Up to now, in known configurations the ion exchanger inserts or cartridges have been arranged horizontally within the vehicle which has caused channel formation, washing out and destruction of the ion exchange material of the cartridge. This has the result that the cooling medium seeks the path of least resistance through the cartridge and flows through the ion exchanger without exchange of ions into the ion exchange material. By an upright, in particular vertical, arrangement of the ion exchanger in accordance with the invention, this gravity effect is not noticeable. Preferably, the compensation container is positioned always as far as possible at the top within the vehicle for physical reasons in order to ensure a venting function. With the easy accessibility is also enabled that the servicing part in the form of the ion exchanger is comfortably accessible from above and can be exchanged without other components having to be demounted. 
         [0029]    In one embodiment, the cooling fluid container has at its upper end (laterally at the top) an outlet opening for discharging the cooling fluid from the collecting chamber. 
         [0030]    In a further embodiment, the cooling fluid container has a cover for removal and installation of the ion exchanger; the cover has a spring in order to act on an upper wall of the ion exchanger. In this way, the ion exchanger can be further fixed in order to secure it even better with respect to sliding as a result of shaking or the like. 
         [0031]    The spring of the cover for removal and installation of the ion exchanger can also fulfill the additional function of compression of the ion exchange medium. 
         [0032]    In one embodiment, the cooling fluid container has a refill socket for refilling cooling fluid. The refill socket can be closeable by a screw closure which is provided with a pressure compensation system. 
         [0033]    In one embodiment, the screw closure for closing the refill socket can be integrally connected with an ion exchanger cartridge, for example, in such a way that the screw closure by exchanging the ion exchanger cartridge is exchanged together with the latter. 
         [0034]    In a further embodiment, the cooling fluid container has a filling level sensor, preferably provided with a float. A connector of the filling level sensor can be arranged so as to be accessible from the exterior at the bottom of the compensation container. 
         [0035]    The object is finally solved according to the invention by the ion exchanger cartridge with a pressing device for compressing the ion exchange medium. This has the advantage that the ion exchange medium is uniformly compressed and the formation of preferred flow passages is prevented. The ion exchange medium is uniformly flowed through by the fluid to be treated; this increases the ion exchange efficiency and the service life. In this way, the ion exchanger cartridge can be configured to be compact and space-saving. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    The accompanying Figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
           [0037]    Features of the present invention, which are believed to be novel, are set forth in the drawings and more particularly in the appended claims. The invention, together with the further objects and advantages thereof, may be best understood with reference to the following description, taken in conjunction with the accompanying drawings. The drawings show a form of the invention that is presently preferred; however, the invention is not limited to the precise arrangement shown in the drawings. 
           [0038]      FIG. 1  schematically depicts a cooling circuit of a fuel cell system of a motor vehicle with a compensation container in which an ion exchanger cartridge is integrated; 
           [0039]      FIG. 2  schematically depicts a first side view of a first embodiment of a compensation container with ion exchanger cartridge as they are used in the cooling circuit of  FIG. 1 ; 
           [0040]      FIG. 3  schematically depicts a second side view of the compensation container of  FIG. 2 ; 
           [0041]      FIG. 4  schematically depicts a view of the compensation container of  FIG. 2  at a slant from above; 
           [0042]      FIG. 5  schematically depicts a longitudinal section of the compensation container of  FIG. 2  along the line V-V indicated therein; 
           [0043]      FIG. 6  schematically depicts a cross-section of the compensation container of  FIG. 2  along the line VI-VI indicated therein; 
           [0044]      FIG. 7  schematically depicts a longitudinal section of a detail of a second embodiment of a compensation container with ion exchanger cartridge as they are used in connection with the cooling circuit of  FIG. 1 ; 
           [0045]      FIG. 8  schematically depicts a longitudinal section of a detail of a third embodiment of a compensation container with ion exchanger cartridge as they are used in the cooling circuit of  FIG. 1 ; 
           [0046]      FIG. 9  schematically depicts an isometric illustration of an ion exchanger cartridge that is similar to the ion exchanger cartridge of  FIG. 8 ; 
           [0047]      FIG. 10  schematically depicts a cartridge cover of the ion exchanger cartridge of  FIG. 9 ; 
           [0048]      FIG. 11  schematically depicts a section of the cartridge cover of  FIGS. 9 and 10 ; 
           [0049]      FIG. 12  schematically depicts an exploded view of a radiator having a collector in which an ion exchanger cartridge is arranged; 
           [0050]      FIG. 13  is a section illustration of an embodiment of a cooling medium compensation container; 
           [0051]      FIG. 14  depicts a further embodiment of a cooling medium compensation container; and 
           [0052]      FIG. 15  depicts the additional fixation of the ion exchanger by means of a spring according to a further embodiment of a cooling medium compensation container. 
       
    
    
       [0053]    In the above Figures, same components are provided with the same reference characters. 
         [0054]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
       DETAILED DESCRIPTION 
       [0055]    Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of apparatus components related to a cooling device for a fuel cell system. Accordingly, the apparatus components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
         [0056]    In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. 
         [0057]    In  FIG. 1 , a cooling circuit  10  of a fuel cell system  12  of a motor vehicle is illustrated. The fuel cell system  12  may comprise one or several fuel cells. 
         [0058]    The cooling circuit  10  comprises a main conduit system  14  for a cooling fluid which is comprised of cooling water or an aqueous cooling fluid mixture. The main conduit system  14  is connected with the fuel cell system  12  for cooling. In the main conduit system  14  there is moreover a pump  16  for the cooling fluid and a heat exchanger  18  in the form of a radiator. 
         [0059]    The cooling circuit  10  comprises moreover a compensation container  20  for cooling fluid that is illustrated in detail in  FIGS. 2 to 6 . The compensation container  20  is located in a bypass conduit  22  that is fluidically connected with the main conduit system  14 . In the compensation container  20  an ion exchanger cartridge  24  for treating the cooling fluid is integrated. With the ion exchanger cartridge  24  the conductivity of the cooling fluid is reduced. In the main conduit system  14 , a thermovalve  26  is arranged. By means of the thermovalve  26  the flow of the cooling fluid through the bypass conduit  22  and the compensation container  20  is controlled in a way that is of no importance in this context. 
         [0060]    The compensation container  20  illustrated in section in  FIG. 5  comprises a base part  30  that is seal-tightly closed off by a cover part  32 . The cover part  32  is welded to the base part  30 . 
         [0061]    In the compensation container  20  baffle plates  34  for the cooling fluid are arranged that divide the compensation container  20 , as shown in  FIG. 6 , into six chambers  36 . The baffle plates  34  prevent that the cooling fluid splash back and forth when the compensation container  20  moves. The baffle plates  34  have in the lower area through openings  38  through which the cooling fluid can flow between the chambers  36 . In the upper areas, the baffle plates  34  have compensation openings  40  through which air can flow between the chambers  36  in particular for pressure compensation. 
         [0062]    In a receptacle chamber  42  of the compensation container  20  the ion exchanger cartridge  24  is arranged. The receptacle chamber  42  is delimited by an inner cylinder  44  into which the ion exchanger cartridge  24  is inserted. The inner cylinder  44 , as shown in  FIG. 5 , is connected circumferentially seal-tightly with the bottom of the compensation container  20 . The bottom of the compensation container  24  also forms a chamber bottom  46  of the receptacle chamber  42 . The upper rim of the inner cylinder  44  is free so that here connecting openings  48  to the chambers  36  of the compensation container  20  that adjoin the inner cylinder  44  are realized. The stepped chamber bottom  46  that as a whole is funnel-shaped delimits an inflow space  50  into which an inlet socket  52  opens. The inlet socket  52  is connected to the bypass line  22  for supply of cooling fluid into the compensation container  20 . On the inner side of the chamber bottom  46  that is facing the ion exchanger cartridge  24  a support ring that is coaxial to the inner cylinder  44  is integrally formed where the inner cartridge  24  is supported in axial direction. 
         [0063]    The baffle plates  34 , the inner cylinder  44 , and the base part  30  are preferably formed monolithically, preferably of plastic material. 
         [0064]    The ion exchanger cartridge  24  is fluidically connected by means of inflow space  50  and the inlet socket  52  with the bypass line  22 . 
         [0065]    Adjacent to the receptacle chamber  42  in the bottom of the compensation container  20  an outlet opening  54  is arranged that is illustrated in  FIG. 6  and that is surrounded on the exterior side of the compensation container  20  by an outlet socket  56  illustrated in  FIGS. 2 and 3 . The outlet socket  56  is connected to the bypass conduit  22  for discharging cooling fluid out of the compensation container  20 . 
         [0066]    The compensation container  20  has spatially on top at the cover part  32  a receptacle socket  58  with a receptacle opening  60  that is coaxial to the inner cylinder  44  of the receptacle chamber  42 . Through the receptacle opening  60  the ion exchanger cartridge  24  can be introduced into the receptacle chamber  42  of the compensation container  20  and can be easily exchanged. The receptacle socket  58  has an inner thread into which for closing the receptacle opening  60  a cup-shaped receptacle socket  62  with an outer thread is screwed in. The receptacle cover  62  has a circumferential sealing groove  64  with an annular seal  66  that seals the receptacle cover  62  relative to the receptacle socket  58 . The open end face of the receptacle cover  62  is facing the interior of the compensation container  20 . In the interior of the receptacle cover  62 , a hollow push cylinder  68  extending in axial direction is attached, preferably monolithically with the receptacle cover  62 , whose free rim upon screwing in the receptacle cover  62  axially relative to the inner cylinder  44  presses against a pressure disk  70  of the ion exchanger cartridge  24 . 
         [0067]    Adjacent to the receptacle socket  58  on the cover part  32  a refill socket  72  for refilling cooling fluid is arranged. The refill socket  72  is closable with a screw closure that is not shown in the  FIGS. 1 to 6  and that comprises pressure compensation means that are not of interest in this context. 
         [0068]    The ion exchanger cartridge  24  is filled with ion exchange granules  73  that are only schematically indicated in  FIG. 5  and whose function will not be explained any further in this context. The ion exchanger cartridge  24  has a jacket  74  that has outlet openings  76  for the cooling fluid in the upper area. The outlet openings  76  are aligned with the connectors  48  of the inner cylinder  44 . A cartridge bottom  78  of the ion exchanger cartridge  24  has inlet openings  80  illustrated in  FIG. 6  through which the cooling fluid can flow out of the inflow space  50  into the interior of the ion exchanger cartridge  24 . 
         [0069]    The cooling fluid must flow through the ion exchange granules  73  from bottom to top in the direction of arrow  81  and is treated therein. It can only exit from the ion exchanger cartridge  24  through outlet openings  76 . In this way, the flow of the cooling fluid through the ion exchanger cartridge  24  is predetermined. From the outlet openings  76 , the treated cooling fluid flows through the connecting openings  48  into the chambers  36 . From here, the cooling fluid flows through outlet opening  54  and outlet socket  56  into the bypass conduit  22   b.    
         [0070]    The inner cylinder  44  surrounds the ion exchanger cartridge  24  additionally. When using an alternative ion exchanger cartridge, not illustrated, with fluid-permeable, for example, grid-like jacket, the inner cylinder  44  determines the flow of the cooling fluid through the ion exchanger cartridge in that it prevents that the cooling fluid already in a lower area of the ion exchanger cartridge  24  can exit from it through the jacket without having passed through all of the ion exchange granules  73 . 
         [0071]    In the area of the cartridge bottom  78 , the jacket  74  is stepped and is matched to the shape of the chamber bottom  46 . The jacket  74  has a circumferential sealing groove  82  with an annular seal  84 . The annular seal  84  seals the jacket  74  radially against an area that extends at the chamber bottom  46  in axial direction. 
         [0072]    At its upper end face the ion exchanger cartridge  24  is closed off by means of the pressure disk  70  that is slidable in axial direction within the jacket  74  of the ion exchanger cartridge  24 . Upon screwing in the screw closure  62 , the pressure disk  70  is forced by the push cylinder  68  in axial direction and compresses the ion exchange granules  73 . In this way, it is prevented that the cooling fluid will form preferred flow passages within the ion exchange granules  73 . 
         [0073]    The compensation container  20  moreover comprises a filling level sensor  86  with a float  88  illustrated in  FIGS. 5 and 6 . A connector  90  of the filling level sensor  86  illustrated in  FIGS. 2 ,  3  and  5  is arranged, accessible from the exterior, at the bottom of the compensation container  20 . 
         [0074]    In a second embodiment, illustrated in  FIG. 7 , those elements that are similar to those of the first embodiment illustrated in  FIGS. 1 to 6  are provided with the same reference characters so that with respect to their description reference is being had to the explanations regarding the first embodiment. This embodiment differs from the first one in that a cartridge cover  110  is provided that, by means of snap connections  112 , is fixedly plugged onto the jacket  74  of the ion exchanger cartridge  24 . 
         [0075]    The snap connections  112  comprise locking noses and locking eyes interacting in pairs. The locking noses are located on the radial outer circumferential side of the jacket  74 . The locking eyes are arranged on the rim area of the cartridge cover  110 . The push cylinder  68  of the screw closure  62  in axial direction is shorter than in the first embodiment. The free rim of the push cylinder  68  engages the cartridge cover  110  and forces in this way the entire ion exchanger cartridge  24  in axial direction into the receptacle chamber  42 . 
         [0076]    On the inner side of the cartridge cover  110  that is facing the interior of the ion exchanger cartridge  24 , the pressure disk  70  is attached by means of an elastic, approximately hollow cylindrical folded bellows  114 . The folded bellows  114  is coaxial to the jacket  74 . It enables an axial movement of the pressure disk  70  within the jacket  74 . The pressure disk  70  and the folded bellows  114  can be monolithic or can be combined of several components. 
         [0077]    The free rim of the folded bellows  114  is attached to a groove of the cartridge cover  110  and is clamped seal-tightly between the cartridge cover  110  and the free rim of the jacket  74 . The cartridge cover  110 , the folded bellows  114 , and the pressure disk  70  delimit a spring chamber  116 . The spring chamber  116  is seal-tightly closed relative to the interior of the ion exchanger cartridge  24  so that no cooling fluid can pass into the spring chamber  116 . The cartridge cover  110  has a pressure compensation opening  118  to the interior of the push cylinder  68 . The receptacle cover  62  comprises an engagement cylinder  120  that can be engaged by a special tool for opening and closing the cartridge cover  110 . In this way, unauthorized opening of the cartridge cover  110  is made difficult. In the spring chamber  116  a spiral pressure spring  122  is arranged that is coaxial to the jacket  74 . The spiral pressure spring  122  is supported with one end on the inner side of the cartridge cover  110  and with the other end on the side of the pressure disk  70  that is facing the cartridge cover  110 . For centering the spiral pressure spring  122 , annular guide collars  124  and  126  are arranged on the inner side of the cartridge cover  110  and on the corresponding side of the pressure disk  70 , respectively. 
         [0078]    The pressing device with the cartridge cover  110 , the pressure disk  70 , and the spiral pressure spring  122  has the effect that the compression is automatically readjusted, for example, as soon as the ion exchange granules  73  settle. 
         [0079]    In  FIG. 7 , the refill socket  72  is illustrated as being closed with screw closure  128 . Screw closure  128  has a pressure compensation system  130 . 
         [0080]    In a third embodiment, illustrated in  FIG. 8 , those elements that are similar to those of the second embodiment illustrated in  FIG. 7  are provided with the same reference characters so that with respect to their description reference is being had to the explanations of the second embodiment. This embodiment differs from the second one in that the receptacle socket  58  has an outer thread and the receptacle cover  62  has an inner thread and the receptacle cover  62  is screwed onto the receptacle socket  58 . 
         [0081]    The cartridge cover  110  is of a cup-shaped configuration wherein the spiral pressure spring  122  is supported with one end in a depression at the bottom of the cartridge cover  110 . The pressure disk  70  comprises an outer movable rim area  132  that is curved in profile in a semi-circular shape relative to the spring chamber  116 . The movable rim area  132  is attached with its radial outer rim in a groove in the end face of the rim of the cartridge cover  110  and is seal-tightly clamped between the end face rim of the jacket  74  and the end face rim of the cartridge cover  110 . The movable rim area  132  enables in analogy to the folded bellows  114  of the second embodiment a movability of the pressure disk  70  axially relative to the ion exchanger cartridge  24 , wherein the spring chamber  116  is closed seal-tightly relative to the interior of the ion exchanger cartridge  24 . 
         [0082]    In  FIGS. 9 to 11 , an ion exchanger cartridge  24  with a cartridge cover  110  is shown that is similar to the ion exchanger cartridge  24  of the third embodiment of  FIG. 8 . In the cartridge cover  110  of  FIGS. 9 to 11  on the end face of its rim there is no groove provided for the outer rim of the movable rim area  132 . 
         [0083]    In  FIG. 12 , a radiator  218  of a cooling circuit, not shown otherwise and is similar to that of  FIG. 1 , is illustrated in an exploded illustration. The radiator  218  comprises in  FIG. 12  at the top a distributor  222  with an inflow socket for cooling fluid. In  FIG. 12 , a collector  220  of the radiator  218  is illustrated at the bottom that comprises a discharge socket  256  for the cooling fluid. Between the distributor  222  and the collector  220  a cooling member  223  is arranged. The collector  220  is a container in the meaning of the invention. In the collector  220 , an inner cylinder  244  is arranged that is open at both end faces. The inner cylinder  244  serves as a receptacle  242  for the ion exchanger cartridge  24  whose jacket in this embodiment is of a continuous grid shape. The collector  220  has at one side a closeable opening  260  through which the ion exchanger cartridge  24  can be pushed into the inner cylinder  244 . 
         [0084]    Instead of the collector  220  also any other area of a radiator that is suitable to provide a receptacle for the ion exchanger cartridge  24  can be considered as a container in the meaning of the invention. 
         [0085]      FIG. 13  shows a further embodiment in which the compensation container  301  is arranged in a fuel cell system of a motor vehicle. The compensation container  301  is arranged in a cooling medium circuit of this fuel cell system and (liquid) cooling medium or cooling fluid used for cooling the fuel cells of the fuel cell system flows through this cooling medium compensation container. As the cooling medium passes through, contaminants such as metal ions are removed from the (liquid) cooling medium. 
         [0086]    For this purpose, the cooling medium compensation container  301  comprises an ion exchanger  302  or an ion exchanger unit that is integrated into the container  301  and is insertable and removable in a detachable non-destructive way into and from the container  301 . In particular, for this purpose a mechanical means for locking the ion exchanger  302  is provided. 
         [0087]    The locking action can be provided by simple locking hooks or locking clips. Also, strips provided with locking projections and extending in radial direction circumferentially about the ion exchanger  302  can be provided. 
         [0088]    The container  301  has a longitudinal axis A wherein substantially centrally a receptacle chamber  303  is formed into which the ion exchanger  302  can be introduced. The ion exchanger  302  is embodied as an elongate cylinder-shaped insert or cartridge and comprises an ion exchange material  304  (for example, a suitable ion exchange resin) which is contained in the ion exchanger  302 . The ion exchange material can be provided as loose bulk material in the ion exchanger  302 . The bulk material is then secured solely by the action of gravity at the bottom of the ion exchanger  302  and withstands thus as a result of its weight an undesirable washing out as a result of the cooling medium flow out of the ion exchanger  302 . This embodiment is technically especially simple and moreover inexpensive. Should it be required, the bulk material can also be retained, for example, by means of a screen, frit, fiberglass pads or the like. In the illustrated embodiment, the ion exchanger  302  is arranged vertically in the container  301 ; this means that the axis A corresponds to the longitudinal axis of the ion exchanger  302  and therefore a coaxial arrangement of the axes of the ion exchanger  302  and of the container  302  is provided. 
         [0089]    Adjacent to the receptacle chamber  303  that is laterally delimited by vertical walls  305 , the container  301  also has a collecting chamber  306  where the purified cooling medium is collected and returned into the cooling circuit. The collecting chamber  306  surrounds thus in an annular shape the receptacle chamber  303 . Bottom  307  of the receptacle chamber  303  forms at the same time also the bottom of the container  301 . The bottom  307  has an inlet opening  309  that is connected to the cooling medium circuit. Through the inlet opening  309  the cooling medium flows into the receptacle  303 . As a cooling medium, for example, ultra-pure water is suitable. Moreover, as a cooling medium also mixtures of ultra-pure water and ethylene glycol (for example, Glysantin of the company BASF), so-called cooling medium mixtures are suitable. With the illustrated arrows, the flow direction is indicated wherein thus the cooling medium flows from bottom to top through the ion exchanger  302 . The cooling medium or cooling fluid is thus supplied by means of a cooling medium conduit and the inlet opening  309  into the container  301  from the bottom wherein then in the receptacle space  303  a distribution of the cooling medium across the entire surface of the bulk material by means of a fluid-permeable fiberglass pad is achieved. In particular, the bottom of the ion exchanger  302  is arranged in the receptacle space  303  so as to be spaced relative to the inner side of the bottom  307 . 
         [0090]    The cooling medium flows then through the ion exchange material  304  from the bottom to the top. Upon exiting from the ion exchange material  304  it is then introduced in the upper area of the ion exchanger  302  according to the arrows oriented to the left and to the right through a plurality of openings  308  that are formed in the wall of the ion exchanger  302  as well as in the walls  305  so as to pass from the ion exchanger  302  into the collecting chamber  306 . The openings  308  are thus formed in the upper area of the container  301  and also in the upper area of the collecting chamber  306  or the wall that delimits the collecting chamber  306 . The shaft-like receptacle  303  is thus centrally formed at the middle in the container  301 . At the upper end, the ion exchanger  302  and the receptacle chamber  303  can be covered by a cover (not illustrated). 
         [0091]    Laterally at the top, an outlet opening  310  is extending away from the collecting chamber  306  and is coupled to the cooling circuit and is embodied for discharging the cooling medium from the collecting chamber  306  into the cooling circuit. 
         [0092]      FIG. 14  shows a variant of the cooling medium compensation container  301  according to the invention. In contrast to  FIG. 13 , the outlet opening  310  is arranged at the bottom of the cooling medium compensation container  301 . In this way, improved mixing of the cooling medium flowing into the collecting chamber  306  and a safer venting of the cooling circuit can be ensured. The illustrated cooling medium compensation container  301  has moreover two covers: A first cover  311  for removal and installation or exchange of the ion exchanger  302 ; and a second cover  312  for possible refilling or exchanging of the cooling medium or cooling fluid. 
         [0093]    The cover  312 , as shown in  FIG. 15 , can have a spring  313  that acts onto the upper wall of the ion exchanger  302 . In this way, the ion exchanger  302  can be secured, in addition to being secured by the mechanical means for locking, in order to secure it even better with respect to sliding as a result of shaking or the like. 
         [0094]    In all of the above described embodiments of the cooling circuit  10 , of the compensation containers  20 ,  301 , of the ion exchanger cartridges  24 ,  302 , and of the radiator  218  the following modifications are possible inter alia. 
         [0095]    The invention is not limited to circuits  10  of fuel cells systems  12  of motor vehicles. It can be used also in stationary fuel cells systems or in cooling devices of other types of functional systems, for example, internal combustion engines or air-conditioning devices. 
         [0096]    Instead of the ion exchanger cartridges  24 ,  302  also different ion exchangers or different treatment units, for example, filters for cooling fluid can be integrated in the compensation containers  20 ,  301  or the radiator  218 . 
         [0097]    The ion exchanger cartridges  24 ,  302 , instead of being exchangeable, can also be arranged fixedly within the compensation containers  20 ,  301 . For example, also self-regenerating treatment units can be provided that must not be exchanged. 
         [0098]    The receptacle openings  64  for the ion exchanger cartridges  24 ,  302 , instead of being arranged at the top, can also be arranged laterally or at the bottom in the compensation containers  20 ,  301 . 
         [0099]    The ion exchanger cartridges  24 ,  302  or other types of treatment units can be integrated into other types of containers for the cooling fluid instead of into the compensation containers  20 ,  301 . 
         [0100]    Instead of the inner cylinders  44  with the jackets  74  of the ion exchanger cartridges  24 ,  302  provided only at the top with through openings  46 , also other types of components can be provided that predetermine the flow of the cooling fluid through the ion exchanger cartridges  24 ,  302 . It is also possible to provide either the inner cylinders  44  or the jackets  74  of the ion exchanger cartridges  24 , 301  that are only open the top. When using inner cylinders  44 , also ion exchanger cartridges can be used that have fluid-permeable jackets across their entire height. 
         [0101]    Instead of the baffle plates  24 , also other types of baffle devices or splash guard devices, for example, splash ribs for the cooling fluid can be arranged in the compensation containers  20 . 
         [0102]    The cooling circuit  10  can also be configured in a different way. For example, the compensation containers  20 ,  301  can be arranged at different locations, also within the main conduit system  14 , instead of in the bypass conduit  22 . The compensation containers  20 ,  301  with the ion exchanger cartridge  24 ,  302  can also be arranged at the hot side of the cooling circuit  10 . 
         [0103]    Instead of being welded, the cover parts  32  can also be connected seal-tightly with the base parts  30  of the compensation containers  20 , 301  in a different way, for example, screwed. 
         [0104]    The ion exchanger cartridges  24 ,  302  can also be used in other types of devices for treating various fluids instead of in cooling devices. 
         [0105]    The flow of the cooling fluid through the compensation containers  20 ,  301  can also be realized in reverse direction. The functions of the inlet socket  52  and of the outlet socket  56  are then switched. The ion exchanger cartridge  24 ,  302  is then flowed through from top to bottom. The supply of cooling fluid into the compensation container can also be realized from above. 
         [0106]    In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.