Abstract:
A device for treating water having a cartridge, which includes a container for receiving treatment means and a connecting head. Furthermore, a connecting device is provided, which is equipped with a holder, a valve device, and a locking device. The holder has at least one side wall, on which the inflow and outflow openings are disposed. The valve device has a valve element, which surrounds the connecting head at least partially and is disposed movably in the holder. The associated cartridge provides at least one inlet opening and at least one outlet opening on at least one side surface. The cartridge has at least one recess and/or a lug for the engagement of a locking element of a locking device of the connecting device.

Description:
FIELD OF THE INVENTION 
     The invention relates to an apparatus for treating water, particularly a filter apparatus, with a cartridge, which includes a container for receiving treatment means and a connecting head, which has at least one inlet opening and at least one outlet opening, and which is provided with a connecting device, which is provided with a holder for the connecting head, which has at least one inflow opening and at least one outflow opening, a valve device for opening and closing the inflow opening, and a locking device for the releasable fastening of the cartridge to the connecting device. The invention also relates to a cartridge, especially a filter cartridge. 
     BACKGROUND OF THE INVENTION 
     By the treatment of water is meant, besides filtration, also the graduated delivery of substances to the water. The delivery of substances can also be combined with a filtration of the water. 
     By filter cartridges are meant, on the one hand, those which have a sievelike structure for the mechanical filtration. On the other hand, by filter cartridges are meant those which contain, besides a sievelike structure, at least one filter medium, for example one in granulate form, which serves for the chemical and/or mechanical removal and/or reduction of organic and/or inorganic impurities. Thus, filter cartridges of this kind enable a nonmechanical filtration, which can be combined with a mechanical filtration. These filter cartridges are used for optimization of water, meaning by optimization the mechanical and/or nonmechanical filtration. This includes, e.g., the softening and decalcifying of drinking water. 
     Filtration can be pressure-operated, i.e., it can be carried out with excess pressure, or with partial vacuum, or by gravity forces. 
     A filter apparatus is known from WO 2007/012079 A2 that has a filter cartridge and a connecting device. The connecting device is generally firmly mounted. The filter cartridge is inserted into this connecting device and after the filter material is used up it is exchanged for a new filter cartridge. The insertion process places a load on the gaskets at the connecting head of the filter cartridge and/or the holder of the connecting device, especially when the inserting process involves a rotational movement of the filter cartridge. 
     In order to avoid rotational movements, a locking device is proposed that engages with the holder of the cartridge, in which only a translatory movement of the filter cartridge is required both for the installation and the removal of the filter cartridge. This occasions a costly locking device, one working by the principle of a ball point pen, in which the spring device must be configured and arranged so that at least one of the components of the locking device executes a rotational movement. 
     The water inlet opening of the filter cartridge is disposed at the end face of the connecting head, so that the filter cartridge must be inserted against the direction of flow of the unfiltered water and, thus, against water pressure. In operation of the filter cartridge, the water pressure acts constantly on the filter cartridge and presses it out from the holder. In order to prevent this, yet still fix the filter cartridge securely and immovably in the holder, a stable configuration of the locking device is indispensable. In order to avoid dripping losses when dismounting the filter cartridge, a costly valve construction and a plurality of sealing elements are required. 
     SUMMARY OF THE INVENTION 
     The problem of the invention is to provide an apparatus for the treatment of water that makes do with few structural parts, ensures a safe and tight seat for the filter cartridge, and enables an easy replacement of the cartridge. 
     This problem is solved with an apparatus for treating water comprising a cartridge, which includes a container for receiving treatment means and a connecting head, which has at least one inlet opening and at least one outlet opening, and which is provided with a connecting device, which is provided with a holder for the connecting head, which has at least one inflow opening and at least one outflow opening, a valve device for opening and closing the inflow opening, and a locking device for releasable fastening of the cartridge to the connecting device, wherein the holder has at least one side wall in which the inflow and outflow opening are disposed, and the valve device has a valve element that at least partly surrounds the connecting head and is movably disposed in the holder. 
     By moving inflow and outflow opening to at least one side wall of the connecting head, the pressure of the untreated water streaming into the cartridge acts perpendicularly to the longitudinal axis of the cartridge and, thus, perpendicularly to the direction of insertion, so that the cartridge cannot be forced out from its position by the water pressure during operation. 
     The inlet and outlet openings that cooperate with the inflow and outflow openings are likewise disposed in one side surface of the connecting head. 
     This feature opens the possibility of a simplification of the valve device as compared to the aforementioned prior art. By providing a valve element that at least partly surrounds the connecting head and is movably disposed in the holder, the holder itself is used to guide the valve element. This substantially lowers the costs for the fabrication of the apparatus. 
     The valve element when inserted into the connecting head is moved by the latter from its position of rest to its working position. 
     In the position of rest, the valve element closes at least the inflow opening. When the connecting head is installed, not only the valve element but also the connecting head is moved relative to the valve element until both the connecting head and the valve element have reached their end positions. 
     In this end position, the valve element is in its working position, in which it clears both the inflow opening and the inlet opening opposite the inflow opening, so that the water being treated can flow into the connecting head and thus into the cartridge. 
     When the connecting head is inserted, the outlet opening and the outflow opening are likewise juxtaposed. This can occur without involvement of the valve element. However, it is preferable that the valve element be configured so that it opens and closes the outlet opening and outflow opening in the same way as for the inflow opening. 
     The valve element is movably disposed in the holder. Preferably, the valve element is movable at least in the axial direction, i.e., in the direction of the longitudinal axis of the filter cartridge or the connecting device. By this axial mobility is meant a displacement without a rotary component. 
     Preferably, the valve element is disposed between at least one side wall of the holder and the connecting head. The valve element lies against the side wall of the holder and is preferably movably disposed on the side wall. How the valve element can be movably disposed depends essentially on the movement that occurs during the insertion process. 
     The valve element is therefore preferably mounted capable of displacement and/or rotation in the direction of the longitudinal axis of the holder. By rotational mounting is meant a rotary movement about the longitudinal axis of the holder. The longitudinal axis of the holder coincides with the direction of insertion of the connecting head. 
     According to one embodiment it is provided that the connecting head is inserted in the axial direction into the valve element and moved axially in the axial direction with the valve element as far as the end position of the valve element; in the end position, a fixation of the connecting head occurs, especially a locking. For the unlocking, a rotary movement of filter cartridge and valve element is carried out. This design is known as a push-turn design. 
     According to the second embodiment, the unlocking likewise occurs by an axial movement of the filter cartridge and the valve element in the opposite direction to the insertion, the so-called push-pull design. 
     The valve element for the opening and closing of the inflow opening can be moved out from the region of the inflow opening or into the region of the inflow opening, respectively. According to one special embodiment, the valve element has at least one recess or at least one opening that is moved in front of the inflow opening to open the inflow opening. Another recess and/or opening can be provided for the outflow opening. 
     Preferably, the valve element is a platelike element, a shell-like element or a sleeve. The configuration of the valve element depends essentially on the outer contour of the connecting head and the inner contour of the holder. Accordingly, the outer contour in the case of a sleeve can be fashioned round or polygonal, for example. 
     The holder and/or the connecting head preferably have a rectangular or trapezoidal cross section, which in contrast with round cross sections facilitates the proper positioning of the connecting head in the holder. The rectangular or trapezoidal cross sectional contours are realized in complementary manner to the valve element. 
     Other cross sections, such as circular arcs with straight segments, are likewise preferred. 
     Preferably, the valve element has a bottom at the side facing the end face of the holder. The bottom can serve as a surface of engagement for an activating device, especially a spring device, in order to move the valve element into its position of rest. When the valve element is fashioned as a sleeve, the bottom gives the valve element the shape of a cup or pot. 
     The valve has preferably one through channel in or beneath the bottom, which extends in particular perpendicular to the longitudinal axis. When the connecting device is hooked up to a water pump, for example, that delivers water continuously, it is advantageous if the pump does not need to be switched off during the replacement of the cartridge. The through channel is provided in order to maintain the water flow, connecting the inflow opening to the outflow opening in the position of rest of the valve element. This creates a bypass, through which the water is taken untreated. 
     The inlet opening and the outlet opening of the connecting head are preferably disposed on opposite sides. The corresponding inflow and outflow openings of the holder are likewise placed oppositely. In this embodiment, the through channel can be configured as a straight through borehole in the bottom of the valve element. 
     The locking device preferably has a spring device that is disposed between the holder and the valve element. The spring device thus acts on the valve element and can be used to move the valve element, especially in order to move the valve element into its position of rest or to hold the valve element in its position of rest. 
     The spring device is preferably a compression spring. 
     Two different configurations of the compression spring are preferred. 
     According to a first embodiment, the compression spring is disposed between the end face of the holder and the valve element. The compression spring acts in the direction of the longitudinal axis of the holder and displaces the valve element. When the valve element preferably has a bottom, the compression spring can engage with this bottom. 
     One preferred embodiment of the compression spring is a helical spring. The compression spring can additionally be configured also as a torsion spring. The configuration of the compression spring as a torsion spring is advantageous when the valve element is rotationally mounted in the holder and the unlocking occurs by a rotational movement. 
     Instead of a combined compression and torsion spring, two springs can also be provided, namely, one compression spring and one torsion spring. 
     The compression spring, the torsion spring or the combined compression and torsion spring can also be disposed in a middle region of the holder. This spring preferably encloses the valve element, which advantageously shortens the overall length of the connecting device. 
     According to another embodiment, the compression spring is disposed between a side wall of the holder and the valve element. The compression spring acts on the valve element perpendicularly to the longitudinal axis of the holder and in this way secures the valve element in the desired position. 
     The compression spring is preferably mounted in a side wall of the holder. 
     According to one special embodiment, the compression spring is configured as a leaf spring. The leaf spring preferably has a V-shaped segment, and this V-shaped segment can make contact with the valve element. 
     The valve element has, in its outer surface, at least two neighboring recesses for engaging with the leaf spring. The two recesses create two detent positions, so that the valve element can be secured in its position of rest and in its working position. When the valve element is shifted in the direction of the longitudinal axis of the holder, the leaf spring is forced out from the recess and thereby tensioned. When the neighboring recess of the preferably V-shaped segment is reached, the leaf spring engages with this recess and secures the valve element in the respective position. 
     The locking device has at least one locking element that engages with the connecting head. By engaging with the connecting head, the locking device has an especially compact form. 
     So that the locking element can engage with the connecting head, preferably a recess and/or a lug is provided on the connecting head. After the connecting head is inserted, the at least one locking element engages with this recess or with the lug. 
     According to a first embodiment of the locking mechanism, the locking element is configured so that it locks during a translatory inserting movement of the connecting head and unlocks during a rotary movement of the connecting head. 
     The locking element according to one special embodiment is a locking pawl. The locking pawl can be disposed in one side wall of the holder. The locking pawl is preferably oriented parallel to the longitudinal axis of the holder. 
     During the translatory inserting of the connecting head, the locking pawl engages in the recess or with the lug. By a rotary movement, the locking pawl slips out from the recess or moves past the lug, thereby releasing the locking. 
     According to a second embodiment, the locking element is configured so that it locks during a translatory insertion movement of the connecting head and unlocks during an oppositely directed translatory movement for removal of the connecting head. 
     The locking element is preferably a flexible rod with a snap-in head. 
     The flexible rod can be disposed on the outside of the valve element. When the valve element is moved, the locking element is moved along with it. The valve element in this embodiment is part of the locking device. 
     The snap-in head extends through the valve element preferably inwardly, so as to engage with the lug or recess of the connecting head. 
     The flexible rod with the snap-in head is preferably guided in a slotted link that is provided in one side wall of the holder. Due to the movement of the valve element, the locking element is moved relative to the holder and thus relative to the side wall of the holder. Thanks to the link, the movement of the snap-in head can be specifically guided perpendicular to the direction of displacement, which occurs in the direction of the longitudinal axis. In this way, it is possible to deliberately control the engaging of the snap-in head, e.g., in the recess, and the releasing of the snap-in head for the unlocking. 
     The connecting head can furthermore have at least one guiding means, which cooperates with a corresponding guiding means inside the sleeve. Such guiding means can be a web and a groove or the like, by which the positioning of the connecting head relative to the connecting device can be defined in unambiguous manner. Such guiding means can also be configured by the lock and key principle, so that only specially provided cartridges can be connected to the particular connecting device. 
     The cartridge according to the invention has a container for holding water treatment agents and a connecting head disposed on the container for connection to a connecting device, wherein the connecting head has on at least one side surface at least one inlet opening and at least one outlet opening and at least one recess and/or lug for engaging a locking element of a locking device of the connecting device. 
     Preferably the connecting head has at least one additional guiding means. 
     Such apparatus find preferred application in refrigerators. Large-volume refrigerators can be provided with a tap, so that water cooled inside the refrigerator and filtered, for example, can be tapped. The connecting device is thus installed permanently in the interior of the refrigerator and connected to the household water line, for example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Two sample embodiments of the invention shall now be further explained by means of the drawings. 
       These show: 
         FIG. 1  a perspective representation of an apparatus for treatment of water with a cartridge and a connecting device, seen from the cartridge side, 
         FIG. 2  a perspective representation according to  FIG. 1 , seen from the connection side, 
         FIG. 3  an enlarged partial view of the left end of the apparatus shown in  FIG. 1  according to a first embodiment at the start of the inserting of the connecting head in the connecting device, 
         FIG. 4  a view looking at the right end of the apparatus per  FIG. 2 , the connecting head being fully inserted into the connecting device, 
         FIG. 5 a    a longitudinal section in the plane V-V of  FIGS. 1 and 3  through the connecting head with valve device during nonfunctional operation for replacement of the cartridge, 
         FIG. 5 b    a longitudinal section per  FIG. 5 a    according to another embodiment, 
         FIG. 5 c    a longitudinal section per  FIG. 5 a    according to another embodiment, 
         FIG. 6  a longitudinal section through the connecting head with valve device per  FIG. 5  during filter operation, 
         FIG. 7  in perspective the locking device for the connecting head with the valve device in the locked state, 
         FIG. 8  a view as in  FIG. 7 , but in the nonlocked state, 
         FIG. 9  an enlarged partial view of the apparatus shown in  FIG. 1  according to a second embodiment at the start of the inserting of the connecting head into the connecting device, 
         FIG. 10  a partial view of the apparatus per  FIG. 9 , where the connecting head has been further inserted, but not yet reached its end position, 
         FIG. 11  a view of the apparatus per  FIGS. 9 and 10 , where the connecting head is fully inserted. 
         FIG. 1  shows a perspective view of an apparatus  1 ,  101  for treatment of water, having a connecting device  40 ,  140  and a cartridge  10 ,  110  connected to the connecting device  40 ,  140 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     We denote with  1  the apparatus according to the first embodiment in accordance with  FIGS. 3 to 8  and with  101  the apparatus according to the embodiment of  FIGS. 9 to 11 . The same holds for the other 1 and 2 or 3-place reference numbers. 
     The cartridge  10 ,  110  has a container  12 ,  112  to hold a treatment agent for water, which is supplied via the connecting device  40 ,  140  of the cartridge  10 ,  110 . The treated water is likewise taken away via the connecting device  40 ,  140 . The cartridge  10 ,  110  can be, for example, a filter cartridge. 
     The connecting device  40 ,  140  is mounted stationary by a mounting plate  43 , for example, in a refrigerator. 
     The cartridge  10 ,  110  has to be replaced after using up the treatment agent located in it. In order to facilitate this process, the container  12 ,  112  has at its rear end a handle  14 ,  114 , by which the cartridge  10 ,  110  can be grasped and twisted, depending on the configuration of the connecting device  40 ,  140 . 
       FIG. 2  is a perspective view of the apparatus  1 ,  101  per  FIG. 1  at the connecting end, so that the two connection fittings  75  for the supply of water being treated and the removal of the treated water, as well as part of the inside of the connecting device  40 ,  140  can be seen. The connection fittings  75 ,  175  are disposed in the rear wall of the connecting device  40 ,  140 . 
     In  FIGS. 3 to 8 , a first embodiment of the apparatus (apparatus  1 ) is shown, being termed the push-turn variant. The cartridge  10  is situated at the beginning of the insertion process per  FIGS. 3 to 5 . 
     The cartridge  10 ,  110  has a connecting head  20  on the container  12 , which in the embodiment shown here has a rectangular cross section. Accordingly, the connecting head  20  has four side surfaces  22   a  to  22   d , only the two surfaces  22   a  and  22   b  being visible. The side surfaces not visible are indicated by broken-line references  22   c  and  22   d.    
     In the surface  22   a  there is shown an inlet opening  30   a . In the opposite side surface  22   c  is located the outlet opening  30   b  (see also  FIGS. 5   a, b, c  and  6 ). On the surface  22   b , moreover, there is provided a lug  24  as an outwardly pointing projection (see also  FIGS. 7 and 8 ). This lug  24  has a bevel  25  on the side facing the connecting device  40  and an abutment surface  26  disposed essentially perpendicular to the surface  22   b  on the side away from the connecting device  40 . This lug  24  cooperates with a locking element  81 , as shall be further described below. 
     The connecting device  40  has a housing  41 , which is fastened to the mounting plate  43 . Inside the housing  41  there is a holder  42  in the shape of a chamber open at one end with side walls  44   a - d  and end face  46 . Moreover, channels  49   a, b  are disposed in the housing  41 , extending in the axial direction and connecting the connection fittings  75  to the inflow and outflow openings  48   a  and  48   b  which emerge into the holder  42 . 
     In the holder  42  is disposed a valve device  50  with a valve element  51  in the form of a sleeve  52 , able to move in the direction of the longitudinal axis  2  of the holder  20 . The sleeve  52  has an inner space  68  whose cross section is adapted to the rectangular cross section of the connecting head  20 . 
     The sleeve  52  has, at the side away from the connecting head  20 , a potlike depression with a bottom  54 . Between the end face  46  of the holder  42  and the bottom  54  of the sleeve  52  is provided a spring device  90 , consisting of a helical spring  92 . The helical spring  92  engages by its two ends with annular shoulders on the bottom  54  and at the end face  46 . The helical spring has a fixation pin  94   a  at one end, which engages in a corresponding recess  95  in the end face  46  of the holder  42 . At the other end of the helical spring  92  is disposed another fixation pin  94   b , which engages in a corresponding recess  96  in the bottom  54  of the sleeve  52 . This helical spring  92  is a compression spring and also serves as a torsion spring at the same time. 
     As can be seen in  FIG. 3  in conjunction with  FIGS. 5 a    and  6 , the sleeve  52  has two oppositely disposed boreholes, which extend perpendicular to the axis  2  and form the openings  58   a, b , by which the inflow opening  48   a  is connected to the inlet opening  30   a  and the outflow opening  48   b  to the outlet opening  30   b  when the connecting head  20  is fully introduced into the connecting device  40 . 
     The sleeve  52  has a through borehole  56  under the bottom  54 , extending perpendicular to the longitudinal axis  2 , which connects the inflow opening  48   a  to the outflow opening  48   b . Water that is supplied from the lower connection fitting  75  via the channel  49  will be taken (see also  FIG. 5   a, b, c ) via the through borehole  56  to the opening  48   b  and drained away via the channel  49   b  in the housing  41  and via the connection fitting  75 . This bypass channel ensures that no water losses occur in the position of rest of the sleeve  52  ( FIG. 5 ), in particular, that no water can emerge uncontrolled, and that the water supply to a connected machine remains intact. 
     On the outside of the sleeve  52 , around the opening  58   a , there is a sealing ring  60 . Another sealing ring  62  is placed around the sealing ring  60  and the opening of the through bore  56  (see also  FIG. 6 ). The two sealing rings  60 ,  62  can form a single part, e.g., in the form of a plate or sealing pad with molded-on sealing rings  60 ,  62 . The part can consist of polypropylene, coated with polytetrafluorethylene in the region of the sealing rings. 
     In  FIG. 5 b    is shown a longitudinal section through an apparatus  1  according to another embodiment. In contrast with the embodiment of  FIG. 5 a   , where the spring  90  is configured both as a compression and a torsion spring, the two functions are divided between two helical springs  92 ,  92   a . Here, the spring  92  is configured as a compression spring and the spring  92   a  as a torsion spring. The sleeve  52  has a reduced outer diameter in the region of the potlike depression, so that the torsion spring  92   a  can be disposed in the annular intermediate space between sleeve  52  and holder  42 . One end of the torsion spring  92   a  is fixed on the sleeve  52 , while the other end is fixed in the rotary direction in a groove extending in the axial direction in the wall of the holder  42  (not shown). In this way, the fixation in the rotary direction remains preserved when the sleeve  52  is shoved in the axial direction. 
     In  FIG. 5 c   , a longitudinal section is shown through an apparatus  1  according to another embodiment, in which the spring device  90  is disposed in a middle region of the connecting device  40 . In contrast with the two previously described embodiments, no space is needed for the spring device between the bottom  54  of the sleeve  50  and the end face  46 , so that the structural length of the connecting device  40  could be shortened. 
     The sleeve  50  has at its end facing the cartridge  10  a radially outwardly projecting annular flange  55 . The housing  41  has an annular shoulder  45  in a middle region of the holder  42 , so that the holder  42  has a diameter-sized segment with which the annular flange  55  engages and is bounded in its movement in the axial direction. Between annular flange  55  and the annular shoulder  45  the spring device  90  in the form of a helical screw is disposed, which likewise combines the two functions (compression spring and torsion spring). The two ends of the helical spring  92  are fixed on the annular shoulder  45  and the annular flange  55 . 
     As shown especially by  FIGS. 7 and 8 , a locking device  80  is provided, having a locking element  81  in the form of a locking pawl  82 . This locking pawl  82  extends parallel to the axis  2  and is mounted in the side wall  44   b  of the holder  42  by means of pivots about an axis  84  extending perpendicular to the axis  2  and able to swivel. The locking pawl  82  is fashioned as a two-arm lever and has a pawl head  86  at the end facing the cartridge  10 , projecting into the inner space of the holder  42 . The pawl head  86  has an abutment surface  88 . 
     When the connecting head of the cartridge  10  is introduced into the inner space  68  of the sleeve  52  (the direction of movement is indicated by the arrow P 1 ), the locking lug  24  engages in a slot  70  of the sleeve  52  (see  FIG. 3  and  FIG. 8  with S the width of the slot), whereupon the bevel  25  radially deflects the locking pawl  82  until the connecting head  20  is fully introduced. The locking pawl  82  springs back to its starting position and presses the lug  24  against the abutment surface  26 . The connecting head  20  is then locked (also see  FIG. 7  for this). 
     In the insertion process, not only is the connecting head  20  introduced into the sleeve  52 , but also the sleeve  52  is pushed against the action of the helical spring  92  into the holder  42 . In this way, all openings  30   a ,  48   a ,  58   a  and  30   b ,  48   b ,  58   b  are brought into line ( FIGS. 6 and 7 ). 
     In this end position, the water brought in through the channel  49   a  is supplied through the opening  58   a  to the inlet opening  30   a , so that the water is introduced into the cartridge  10 . The treated water is taken away in identical fashion through an inner pipe  28  ( FIGS. 5 and 6 ) on the opposite side. This end position, in which the sleeve  52  is in its working position, is shown in  FIG. 6 . The through borehole  56  is without function in this case. 
     To replace the cartridge  10  and remove the sleeve  52  from the holder  42  and the inner space  68 , the cartridge  10  is turned in the direction of arrow P 2  (see  FIG. 7 ). In this way, the sleeve  52  is turned at the same time against the force of the helical spring  92 , likewise acting as a torsion spring ( FIG. 7 ), so that the locking pawl  82  is disengaged from the lug  24  ( FIG. 8 ). Thanks to the restoring force of the pretensioned helical spring  92 , the sleeve  52  is forced outward at the same time and the released cartridge  10  can be pulled out in the axial direction  2  ( FIG. 8 ). 
     In  FIGS. 9 to 11 , the second embodiment of the apparatus (apparatus  101 ) is shown—the so-called push-pull variant, partly in sectional view, whose internal construction differs from the apparatus  1  essentially in a modified valve device  150  and a modified locking device  180 . The cartridge  110  has a container  112  and a connecting head  120  with four side surfaces  122   a  to  d , while one inlet opening  130   a  and one outlet opening  130   b  are disposed in two opposite side surfaces  122   a, c.    
     Instead of a lug  24 , two recesses  126   a, b  are provided in the edge region of the side surfaces  122   a, b  and  122   b, c.    
     The connecting device  140  with housing  141 , connection fittings  175 , channels  149   a, b , inflow opening  148   a  and outflow opening  148   b  as well as holder  142  of the second embodiment corresponds to the first embodiment. The same holds for the through borehole  156  in the bottom  154  of the sleeve  152  and the sealing rings  160 ,  162 . 
     The essential difference from the first embodiment consists in that two locking elements  181  are provided, which are disposed not in one side wall  144   a  to  d  of the holder  142 , but instead on the outside of the sleeve  152 . The locking elements  181  are flexible rods  182   a, b , which at their end away from the cartridge  110  are fixed in the axial direction in the sleeve  152  by lugs  184   a, b  in the bottom  154 . 
     At the opposite end, these flexible rods  182   a, b  each have a snap-in head  183   a, b , the snap-in heads  183   a, b  extending through openings  159   a, b  into the inner space  168  of the sleeve  152  and projecting inwardly relative to the side walls  164   a, c  of the inner space  168 . 
     The side walls  144   a  and  144   b  of the holder  142  each have a slotted link  143   a, b , which basically consists of a bypass space  145   a, b  and a guide path  147   a, b.    
     In the position shown in  FIG. 9 , the sleeve  152  is in its position of rest and ready to receive the connecting head  120 . When the connecting head  120  is inserted in the direction of the longitudinal axis  102  into the inner space  168 , the snap-in heads  183   a, b  slide along the respective side walls  122   a, b  of the connecting head  120  until they reach the recesses  126   a, b  provided there. During this movement process, the snap-in heads  183   a, b  are moved back into the bypass space  145   a, b . At the same time, when the connecting head  120  is inserted the sleeve  152  is also shoved into the holder  142 . Now each snap-in head  183   a, b  reaches its guide path  147   a, b , so that the snap-in heads  183   a, b  are forced inward and engage with the recesses  126   a, b . In the end position, when the snap-in heads  183   a, b  have reached the end region of the respective guide path  147   a, b , the connecting head  120  of the cartridge  110  is fixed in place. 
     The inserting movement of the sleeve  152 —as shown in  FIG. 10 —is against the action of a spring device  190 , which has a leaf spring  192  that has a V-shaped segment  194  in the middle. The leaf spring  192  is disposed in the wall  144   c  of the holder  142  and can be diverted into a free space  147  located in the wall  144   c.    
     The V-shaped segment  194  engages with a recess  153   a  of the sleeve  152 . In this position, the sleeve  152  is fixed in its position of rest. When the connecting head  120  is introduced into the sleeve  152 , at the same time the sleeve  152  is also shoved further into the holder  142 , so that the leaf spring  192  dips into the free space  147  by its segment  194  and the adjoining legs  195 . After overcoming the obstacle  155 , the V-shaped segment  194  of the leaf spring  192  engages with the neighboring recess  153   b , as is shown in  FIG. 11 . In  FIG. 11  one sees the end position and, thus, the locked state. 
     To remove the cartridge  110 , this is pulled back with a translatory movement, whereupon at first the connecting head  120  and the sleeve  152  remain joined together by the flexible rods  182   a, b  and their snap-in heads  183   a, b , so that the valve element  151  is pulled by the cartridge  110  into its position of rest. 
     The V-shaped segment  194  of the leaf spring  192  leaves the recess  153   b  in the sleeve  152  and after overcoming the obstacle  155  arrives at the neighboring recess  153   a.    
     During this movement of the sleeve  152 , the snap-in heads  183   a, b  are moved forward in the slotted links  143   a, b  until they reach the bypass spaces  145   a, b  and spring back into the respective bypass space  145   a, b  thanks to the spring action of the flexible rods  182   a, b . The snap-in heads  183   a, b  leave the recesses  126   a, b  and release the connecting head  120 . The cartridge  110  can now be removed. 
     LIST OF REFERENCE NUMBERS 
     
         
           1  Apparatus for treatment of water 
           2  Longitudinal axis 
           10  Cartridge 
           12  Container 
           14  Handle 
           20  Connecting head 
           22   a - d  Side surface 
           24  Lug 
           25  Bevel 
           26  Abutment surface 
           28  Inner pipe 
           30   a  Inlet opening of the connecting head 
           30   b  Outlet opening of the connecting head 
           40  Connecting device 
           41  Housing 
           42  Holder 
           43  Mounting plate 
           44   a - d  Side wall 
           45  Ring step 
           46  End face 
           48   a  Inflow opening 
           48   b  Outflow opening 
           49   a, b  Channel 
           50  Valve device 
           51  Valve element 
           52  Sleeve 
           54  Bottom of sleeve 
           55  Ring flange 
           56  Through borehole 
           58   a, b  Opening 
           60  Sealing ring 
           62  Sealing ring 
           68  Inner space of sleeve 
           70  Slot 
           75  Connection fitting 
           80  Locking device 
           81  Locking element 
           82  Locking pawl 
           84  Axis 
           86  Pawl head 
           88  Abutment surface 
           90  Spring device 
           92 ,  92   a  Helical spring 
           94   a, b  Fixing pin 
           95  Recess for fixing pin  94   a    
           96  Recess for fixing pin  94   b    
           101  Filter apparatus 
           102  Longitudinal axis 
           110  Cartridge 
           112  Container 
           114  Handle 
           120  Connecting head 
           122   a - d  Side surface 
           126   a, b  Recess 
           130   a  Inlet opening of the connecting head 
           130   b  Outlet opening of the connecting head 
           140  Connecting device 
           141  Housing 
           142  Holder 
           143   a, b  Slotted link 
           144   a - d  Side wall 
           145   a, b  By-pass space 
           147  Free space 
           147   a, b  Guide path 
           148   a  Inflow opening 
           148   b  Outflow opening 
           149   a, b  Channel 
           150  Valve device 
           151  Valve element 
           152  Sleeve 
           153   a, b  Recess 
           154  Bottom of sleeve 
           155  Obstacle 
           156  Through borehole 
           158   a, b  Opening 
           159   a, b  Opening 
           160  Sealing ring 
           162  Sealing ring 
           164   a - d  Side wall 
           168  Inner space of sleeve 
           175  Connection fitting 
           180  Locking device 
           181  Locking element 
           182   a, b  Flexible rod 
           183   a, b  Snap-in head 
           184   a, b  Lug 
           190  Spring device 
           192  Leaf spring 
           194  V-shaped segment 
           195  Leg of leaf spring  192   
         P 1  Insert arrow for cartridge 
         P 2  Turn arrow for cartridge 
         S Slot width