Device for forming a head part of a liquid treatment apparatus and liquid treatment apparatus

Abstract

A device for forming at least part of a head part of a liquid treatment apparatus is arranged to receive a connecting head of a replaceable liquid treatment cartridge and includes at least one ratio-setting valve. The ratio-setting valve is provided with at least two first ports, each placeable in essentially sealed liquid communication with respective cartridge ports of a connecting head of a replaceable liquid treatment cartridge inserted into the device, and with at least one second port. The ratio-setting valve includes at least one movable regulating part for setting a volumetric flow rate ratio between a first flow of liquid between a first of the first ports and the at least one second port and a second flow of liquid between a second of the first ports and the at least one second port at any of a plurality of values.

Claims

1. A device for forming at least part of a head part of a liquid treatment apparatus, wherein the device is arranged to receive a connecting head of a replaceable liquid treatment cartridge and includes at least one ratio-setting valve, wherein the ratio-setting valve is provided with at least two first ports, each placeable in essentially sealed liquid communication with respective cartridge ports of a connecting head of a replaceable liquid treatment cartridge inserted into the device, and with at least one second port, wherein the ratio-setting valve includes at least one movable regulating part for setting a volumetric flow rate ratio between a first flow of liquid between a first of the first ports and the at least one second port and a second flow of liquid between a second of the first ports and the at least one second port at any of a plurality of values, and wherein the ratio-setting valve is placeable in a closed configuration, in which the at least one movable regulating part is positioned such that both the first and the second flows are blocked, and wherein the ratio-setting valve is placeable in the closed configuration independently of whether a connecting head is inserted with its cartridge ports in liquid communication with the first ports.

2. The device according to claim 1, further including: a receiving part including at least one cavity for receiving at least a part of the connecting head including at least one of the cartridge ports such that the cartridge port is in sealed liquid communication with a receiving part port, wherein the receiving part is arranged to receive a connecting head provided with at least two cartridge ports such that each of the cartridge ports of the connecting head are in sealed liquid communication with a respective receiving part port; and at least one valve mechanism, operable by the liquid treatment cartridge, for interrupting flows of liquid between the first ports and respective ones of the receiving part ports.

3. The device according to claim 2, wherein the at least one valve mechanism is additional to the ratio-setting valve.

4. The device according to claim 2, including a part for engaging the liquid treatment cartridge when the connecting head is inserted into the device wherein the liquid treatment cartridge is movable with the engaging part between a first and a second position relative to a main part of the device whilst the connecting head is inserted, and wherein a position of the engaging part relative to the main part determines a state of the valve mechanism, the first ports being in liquid communication with the receiving part ports only in the second of the first and second positions.

5. The device according to claim 4, wherein the receiving part is arranged to engage the liquid treatment cartridge when the connecting head is inserted into the cavity of the receiving part.

6. The device according to claim 2, wherein the device includes at least one inlet and at least one outlet for liquid, wherein the second port is at least placeable in liquid communication with one of at least one of the inlets and one of the outlets, and wherein the valve mechanism is arranged to place the first ports in liquid communication with the other of at least one of the inlet and at least one of the outlets when the flows of liquid between the first ports and respective ones of the receiving part ports are interrupted.

7. The device according to claim 1, wherein the device is provided with at least one inlet and at least one outlet for liquid and at least two of the ratio-setting valves, and wherein the second port of a first of the ratio-setting valves is at least placeable in liquid communication with at least one of the inlets and the second port of a second of the ratio-setting valves is at least placeable in liquid communication with at least one of the outlets.

8. The device according to claim 1, including a receiving part including a cavity provided with multiple receiving part ports placeable in sealed liquid communication with the respective cartridge ports on insertion of the connecting head into the cavity.

9. The device according to claim 8, wherein the receiving part includes a cavity provided with at least three receiving part ports.

10. The device according to claim 9, wherein the cavity is provided with at least four receiving part ports.

11. The device according to claim 1, including a movable operating part for at least placing the ratio-setting valve in and out of the closed configuration.

12. The device according to claim 11, wherein the movable operating part is journalled for rotation about an axis fixed with respect to the device.

13. The device according to claim 12, wherein the movable operating part is arranged such that liquid conducted through at least one of the first ports and the second port is led through a central section of the movable operating part.

14. The device according to claim 11, wherein the at least one moveable regulating part includes a regulating part having a surface sealingly placed against the first ports and having an aperture therein, the aperture being moveable between positions of varying degrees of overlap with the first ports and into at least one position out of overlap with any of the first ports, and wherein the regulating part is one of coupled for movement with and comprised in the movable operating part.

15. The device according to claim 1, wherein the at least one movable regulating part includes a regulating part having a surface sealingly placed against the first ports and having an aperture therein, the aperture being movable between positions of varying degrees of overlap with the first ports and into at least one position out of overlap with any of the first ports.

16. The device according to claim 15, wherein the regulating part is rotatable and the positions correspond to rotary positions.

17. A liquid treatment apparatus including a head part including at least one device according to claim 1 and at least one replaceable liquid treatment cartridge.

18. A liquid treatment apparatus according to claim 17, wherein at least three cartridge ports in liquid communication with an interior of the liquid treatment cartridge are provided in the connecting head.

19. The liquid treatment apparatus according to claim 18, wherein at least four cartridge ports in liquid communication with an interior of the liquid treatment cartridge are provided in the connecting head.

20. The liquid treatment apparatus according to claim 17, wherein the at least one device includes a moveable operating part for at least placing the ratio-setting valve in and out of the closed configuration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in further detail with reference to the accompanying drawings, in which:

(2) FIG. 1 is a perspective view of a liquid treatment apparatus including a head part and a replaceable liquid treatment cartridge;

(3) FIG. 2 is a perspective view of a mounting plate for the head part;

(4) FIG. 3 is a perspective view of a cap-shaped part of the liquid-treatment cartridge;

(5) FIG. 4 is a first side view of the cap-shaped part of FIG. 2;

(6) FIG. 5 is a second side view of the cap-shaped part of FIGS. 2 and 3;

(7) FIG. 6 is a cross-sectional view of the cap-shaped part of FIGS. 2-4;

(8) FIG. 7 is simplified cross-sectional view of a vessel-shaped part of the liquid treatment cartridge and flow conducting parts arranged therein;

(9) FIG. 8 is a perspective view of the interior of the head part of the liquid treatment apparatus in which a part of a housing of the head part has been omitted;

(10) FIG. 9 is a first perspective view of an underside of a receiving part movably journalled in the housing;

(11) FIG. 10 is a second perspective view of the underside of the receiving part of FIG. 8;

(12) FIG. 11 is a bottom view of the receiving part of FIGS. 8-10;

(13) FIG. 12 is a perspective view of the receiving part from the side;

(14) FIG. 13 is a plan side view of the receiving part;

(15) FIG. 14 is a perspective view of a latching device arranged inside the housing of the head part to hold the receiving part in a first of first and second positions;

(16) FIG. 15 is a perspective view of the interior of the head part with the receiving part and part of the housing of the head part omitted;

(17) FIG. 16 is side view of a left part of the housing;

(18) FIG. 17 is a perspective view of the housing with an operating part of a ratio-setting valve omitted;

(19) FIG. 18 is a second perspective view of the housing, with the operating part and a regulating part of the ratio-setting valve omitted;

(20) FIG. 19 is a perspective view of only the left housing part;

(21) FIG. 20 is a plan side view of an inside of the left housing part;

(22) FIG. 21 is a perspective view of the inside of the left housing part;

(23) FIG. 22 is a perspective view of the inside of the left housing part with a screening part mounted thereto;

(24) FIG. 23 is a first perspective view of the screening part;

(25) FIG. 24 is a second perspective view of the screening part;

(26) FIG. 25 is a thirds perspective view of the screening part with a movable regulating part of a ratio-setting valve in place;

(27) FIG. 26 is a first perspective view of an operating part of the ratio-setting valve;

(28) FIG. 27 is a plan view of the operating part of FIG. 26;

(29) FIG. 28 is a second perspective view of the operating part of FIGS. 26 and 27;

(30) FIG. 29 is a first perspective view of a movable regulating part of the ratio-setting valve;

(31) FIG. 30 is a first plan view of the movable regulating part of FIG. 29;

(32) FIG. 31 is a second plan view of the movable regulating part of FIGS. 29 and 30;

(33) FIG. 32 is a plan view of a right part of the housing of the head part;

(34) FIG. 33 is a perspective view of an inside of the right housing part with a screening part mounted thereto;

(35) FIG. 34 is a perspective view corresponding to that of FIG. 33, but with the screening part omitted to show a movable regulating part of a ratio-setting valve;

(36) FIG. 35 is a perspective view corresponding to that of FIG. 34, but with the ratio-setting valve omitted;

(37) FIG. 36 is a first perspective view of the screening part of FIG. 33;

(38) FIG. 37 is a second perspective view of the screening part of FIGS. 33 and 36; and

(39) FIG. 38 is a plan view of the screening part of FIGS. 33 and 36-37, with parts of the ratio-setting valve in place.

DETAILED DESCRIPTION

(40) In the following, a liquid treatment apparatus (FIG. 1) for the treatment of aqueous liquids such as drinking water will be described. The liquid treatment apparatus includes a head part 1 and a replaceable liquid treatment cartridge 2. The head part 1 in this embodiment is for receiving a single liquid treatment cartridge 2. In another embodiment, it may be a multi-head device for receiving a number of liquid treatment cartridges. The head part 1 includes a housing comprising left and right housing parts 3,4 joined together to form a housing. A mounting plate 5 (FIG. 2) allows the head part 1 to be mounted to a wall. The housing formed by the left and right housing parts 3,4 is also referred to as the main part of the head part herein. A receiving part 6 is movably journalled within the housing of the head part 1.

(41) The liquid treatment cartridge 2 is of the type described more fully in international patent application No. PCT/EP2015/050155 of 7 Jan. 2015, the contents of which are hereby incorporated by reference. It has a housing formed by a cap-shaped part 7 (FIGS. 3-6) and a vessel 8 (FIG. 7), closed at one end by the cap-shaped part 7.

(42) The cap-shaped part 7 includes an integral connecting head 9. The connecting head 9 is insertable into a cavity of the receiving part 6 in a first position of the receiving part 6 with respect to the housing of the head part 1.

(43) A reference axis (FIGS. 4 and 5) referred to herein as cartridge axis 10 is an axis extending from a closed end of the vessel 8 to the end of the cartridge 2 at which the connecting head 9 is provided. In the illustrated embodiment, the cartridge 2 has an elongated shape and the cartridge axis 10 corresponds to a longitudinal axis of the cartridge 2.

(44) The connecting head 9 is provided with four cartridge ports 11-14 in liquid communication with an interior of the cartridge 2. First and second ports 11,12 are provided in a first surface section 15 (FIG. 4) facing in a direction at an angle to the cartridge axis 10 such that the connecting head 9 tapers towards the axial end of the cartridge 2 at which the connecting head 9 is provided. Third and fourth cartridge ports 13,14 are provided in a second surface section 16 (FIG. 5) facing at an angle to the cartridge axis 10 such that the connecting head 9 tapers towards the axial end of the cartridge 2 at which the connecting head 9 is provided. The angle is larger than 45, but smaller than 90 to achieve the taper. The first and second surface sections 15,16 face in directions of which the lateral components (with respect to the cartridge axis 2 are oppositely directed. There is thus a pair of cartridge ports 11-14 on each of opposite sides of the connecting head 9. One of the pairs is arranged to function as inlets for liquid and the other of the pairs is arranged to function as outlets for liquid. The first and second cartridge ports 11,12 are arranged in a row parallel to the cartridge axis 10, as are the third and fourth cartridge ports 13,14. Furthermore, the first cartridge port 11 is aligned with the third cartridge port 13 and the second cartridge port 12 is aligned with the fourth cartridge port. Exact alignment is not required, however. Grooves are provided for mounting sealing rings (not shown) around the cartridge ports 11-14. The first and second surface sections 15,16 are essentially planar, so that the sealing elements are compressed relatively uniformly when pressed against a co-operating surface to form seals around the cartridge ports 11-14. Due to the taper, the sealing elements are only compressed when the connecting head 9 is close to fully inserted into the cavity of the receiving part 6. This helps avoid wear or dislocation of the sealing elements during insertion.

(45) The cartridge ports 11-14 are each provided at an end of a respective channel 17-20 through the connecting head 9 (FIG. 6). End sections of at least the central three channels 17-19 are arranged concentrically, centred on the cartridge axis 10. They are directed essentially axially into the interior of the cartridge housing. The ends of the first to third channels 17-19 each terminate at a different respective axial position, so that these interior ends are provide within at least one of the other channels 18-20. Liquid can mingle at these ends unless they are separated by separate flow conductor parts.

(46) This is in fact the case for the example used herein, in which flow conductor parts are plugged into the ends of the first and second channels 17,18.

(47) One of these is a fall tube 21 (FIG. 7) extending to close to an opposite axial end of the cartridge 2 in this example. It passes through a flow distributor device 22 arranged at that end. The flow distributor device 22 adjoins a first bed 23 of granular liquid treatment medium. The liquid treatment medium may in particular include ion exchange resin, for example cation exchange resin. A cation exchange resin with a relatively high volumetric capacity is weakly acidic cation exchange resin. Regardless of the type, at least initially, a majority of the cation exchange resin by number of functional groups per unit volume may be in the hydrogen form. This medium is suitable for reducing the carbonate hardness of water contacting it. A minority of the cation exchange resin may be loaded with an alkali metal, e.g. potassium or sodium, for buffering purposes. Other sorbents such as activated carbon may be included in the liquid treatment medium of the first bed 23. A liquid-permeable divider part 24 separates the first bed 23 from a second bed 25 of granular liquid treatment medium differing in composition from the first bed 23. In an example, the second bed 25 includes only liquid treatment media other than liquid treatment media for the treatment of liquid by ion exchange, e.g. sorbents such as activated carbon. In another example, it includes only liquid treatment media other than cation exchange material, e.g. at least an anion resin. A concentric flow conductor 26 is arranged around an axial section of the fall tube 21 proximal to the connecting head 9 and plugged into an end section of the second channel 18. Its other end terminates in the second bed 25. Thus, liquid entering the cartridge 2 through the second cartridge port 12 bypasses the first bed 23, whereas liquid entering through the first cartridge port 11 is conducted through the first bed 23. The two flows mix in the second bed 25. The mix of liquid can leave the cartridge through the third and the fourth cartridge ports 13,14 simultaneously. A liquid-permeable screen 27 retains the material of the second bed 25.

(48) The volumetric flow rate ratio of the flows of liquid entering the cartridge through the first cartridge port 11,12 can be set by means of a ratio-setting valve in the head part 1, as will be explained further below.

(49) Returning to the exterior of the connecting head 9 (FIGS. 3-5), first and second alignment ridges 28,29 are provided adjacent the first and second cartridge ports 11,12 and adjacent the third and fourth cartridge ports 13,14 respectively. The alignment ridges 28,29 extend in a direction essentially parallel to the cartridge axis 10. Axial ends 30,31 distal to the axial end of the cartridge 2 at which the connecting head 9 is provided are rounded.

(50) The alignment ridges 28,29 are provided on curved surface sections 32,33 in this example. These surface sections 32,33 face in directions at an angle to the cartridge axis 10 such that the connecting head 9 tapers in axial direction towards the axial end of the cartridge 2 at which the connecting head 9 is provided. Each of the alignment ridges 28,29 has a first section 34,35 extending to the end distal to the axial end of the cartridge 2 at which the connecting head 9 is provided. Each of the alignment ridges 28,29 has a second section 36,37 extending to the end proximal to the axial end of the cartridge 2 at which the connecting head 9 is provided. There is a stepped transition between the first and second sections 34-37. The stepped transition is such that the elevation with respect to the curved surface section 32,33 decreases stepwise from the first section 34,35 to the second section 36,37. Furthermore, the elevation of the second section 36,37 with respect to the curved surface section 32,33 on which it is provided increases in axial direction towards the axial end of the cartridge 2 at which the connecting head 9 is provided. This compensates for the taper of the connecting head 9. It is noted that, although the curved surface sections 32,33 do not face in exactly opposite directions, due to their curvature, the alignment ridges 28,29 do protrude in opposite directions. These directions are perpendicular to a reference plane in which the cartridge axis 10 lies, which plane is parallel to or contains a locus of movement of the connecting head 9 whilst inserted into the receiving part 6. This aids in converting a force exerted by an operator on the cartridge 2 into movement of the cartridge 2 and the receiving part 6.

(51) The receiving part 6 (FIGS. 8-13) includes a body and, in this example, first to sixth sealing elements 38-43. The body defines the cavity for receiving the connecting head 9. The cavity has a shape corresponding to that of the connecting head 9. It thus tapers in axial direction towards the end distal to the mouth of the cavity.

(52) It is possible to define a reference axis 44 (FIG. 12) aligned with the cartridge axis 10 when the connecting head 9 is inserted into the cavity. This reference axis 44 is thus essentially perpendicular to the mouth of the cavity. The reference axis 44 lies in a plane of movement of the receiving part 6 between a first and a second position with respect to the housing formed by the housing parts 3,4.

(53) Liquid-permeable ports 45-48 are provided in and through opposing first and second receiving part side wall sections 49,50. First and second ports 45,46 are provided in a first side wall section 49. Third and fourth ports 47,48 are provided in a second side wall section 50. Each of the side wall sections 49,50 is at an angle to the reference axis 44 such that the cavity tapers towards the end distal to the mouth.

(54) In the illustrated example, each of the side wall sections 49,50 is essentially planar to allow it to compress the sealing elements provided around the cartridge ports 11-14.

(55) When the connecting head 9 is fully inserted into the cavity, each of the cartridge ports 11-14 is in direct, sealed liquid communication with one of the receiving part ports 45-48. The seals isolate the flows of liquid through the cartridge ports 11-14 and the receiving part ports 45-48 from each other as well as from the cavity.

(56) Alignment grooves 51,52 (FIGS. 9-11) are at least open to the cavity and in this example also at axial ends adjacent a mouth of the cavity. These alignment grooves 51,52 are for receiving the first and second alignment ridges 28,29 on the connecting head 9 of the cartridge 2. They are on opposite sides of the cavity, facing each other. First (lower) sections 53,54 extend through the side wall sections of the receiving part 6 in which they are provided to form slits through these side wall sections. These sections 53,54 are provided at axial ends proximal to the mouth of the cavity. Second (upper) alignment groove sections 55,56 are shaped as slots. The depth of each of the second alignment groove sections 55,56 increases in axial direction towards the end of the cavity distal to the mouth of the cavity, thus compensating for the taper of the cavity. The first alignment ridge sections 34,35 have an elevation relative to the curved surface sections 32,33 from which they protrude that exceeds the thickness of the wall where the first alignment groove sections 53,54 are provided, in this example. The axial, in this example rounded, ends 30,31 of the alignment ridges 28,29 also protrude from the axial ends of the grooves 51,52 when the connecting head 9 is fully inserted into the cavity. This allows them to contact support surfaces 57,58 defined by ledges 59,60 on the insides of the left and right housing parts 3,4 in the second position and whilst the receiving part 6 moves from the first into the second position.

(57) The receiving part ports 45-48, since they pass through a side wall section 49,50 of the receiving part 6, are also externally accessible. This allows them to form part of a valve mechanism similar to a sliding gate valve mechanism, of which the receiving part 6 forms the movable valve member.

(58) First to fourth receiving part sealing elements 38-41 each surround one of the receiving part ports 45-48 on the outside (FIGS. 9, 10, 12 and 13). The fifth and sixth receiving part sealing elements 42,43 surround the first and second receiving part ports 45,46 and the third and fourth receiving part ports 47,48, respectively. They also each surround one of opposite openings of a bypass channel 61 extending through the body of the receiving part 6. The bypass channel 61 thus extends from a side of the receiving part 6 on which ports functioning as inlet openings are provided to a side of the receiving part 6 on which ports functioning as outlet openings are provided. These are opposite sides with respect to a central plane of movement of the receiving part 6 between the first and second positions with respect to the main part of the head part 1.

(59) The main part of the head part 1 has first ports 62-65 of ratio-setting valves defined therein (FIGS. 15, 22 and 33). These first ports 62-65 are also part of the valve mechanism comprising the receiving part 6, since they are aligned with the receiving part ports 45-48 and in direct, sealed liquid communication with them in the second position of the receiving part. The fifth and sixth receiving part sealing elements 42,43 surround these first ports 62-65 in the first, the second and all intermediate positions, so that liquid cannot leak out between the receiving part and the housing parts 3,4. This also ensures that liquid can pass from the first ports 62,63 on one side of the receiving part 6 to the first ports 64,65 on the opposite side of the receiving part 6 when the receiving part ports 45-48 are not in complete alignment with the first ports 62-65, i.e. in positions other than the second position, especially in the first position.

(60) It is noted that the first ports 62-65 are provided in wall sections having an essentially planar surface 66,67 facing the receiving part 6. This allows for uniform compression of the receiving part sealing elements 38-41 at each position between the first and second positions, given that movement between the first and second positions is along a locus in a plane parallel to the planar surfaces 66,67.

(61) The receiving part 6 is journalled for movement between the first and second positions by way of guide protrusions 68-71 on the receiving part 6 and guides 72-75 defined on the inside of the left and right housing parts 3,4 for receiving the guide protrusions 68-71. The movement is a combination of a displacement of the receiving part 6 and an internal rotation, so that the cartridge 2 swivels and is displaced, e.g. in a direction to and from a wall on which the head part 1 is mounted. During this movement, the support surfaces 57,58 support the cartridge 2 by the rounded ends 30,31.

(62) The ledges 59,60 prevent retraction of the connecting head 9 in the second position and all other positions leading up to the first position. This is because they obstruct the first sections 34,35 of the alignment ridges 28,29. Gaps 76,77 adjacent the ledges 59,60 (FIGS. 20-22, 33 and 34) are aligned with the alignment grooves 51,52 in the first position to allow the connecting head 9 to be inserted and retracted in that position.

(63) This position of the receiving part 6 should be retained after a connecting head 9 has been retracted to allow the connecting head 9 of a replacement cartridge 2 to be inserted and also to keep the ends of the bypass channel 61 in full alignment with the first ports 62-65. To this end, a latching device 78 (FIG. 14) is provided.

(64) In the illustrated embodiment, the latching device 78 is a single resilient, essentially U-shaped insert having pawls 79,80 at respective free ends of its arms 81,82. Part of the receiving part 6 is received between the arms 81,82 in the first position. In that position, the pawls 79,80 engage the first sections 53,54 of the alignment grooves 51,52 when not occupied by the first alignment ridge sections 34,35.

(65) When the receiving part 6 is moved into the first position, it forces the arms 81,82 apart. When the cartridge 2 is then retracted, the pawls 79,80 snap into place. When the connecting head 9 of the replacement cartridge 2 is inserted into the cavity of the receiving part 6, the first alignment ridge sections 34,35 urge the pawls 79,80 out of the slits formed by the first alignment groove sections 53,54. This releases the receiving part 6, which can then be moved out of the first position towards the second position. Because the first alignment ridge sections 34,35 engage the pawls 79,80 and there is a stepped transition between the first sections 34,35 and the second sections 36,37, the receiving part 6 is only released when the connecting head 9 has been fully inserted and is also able to clear the ledges 59,60.

(66) To ease the engagement, the pawls 79,80 are provided with facets 83-86. Downwardly directed facets 83,84 are for engaging the first alignment ridge sections 34,35. They face in part in a direction opposite to the direction of insertion of the connecting head 9 and in part towards each other. Facets 85,86 for engaging the receiving part face in part in a direction of movement of the receiving part 6 out of the first position and in part towards each other. Surfaces on an opposite side of the pawls 79,80 to the facets 85,86 that engage the receiving part 6 are essentially at right angles to the adjacent arm sections to provide a relatively strong shape-lock in co-operation with the first groove sections 53,54. Thus, the receiving part 6 is held in the first position.

(67) A means of retaining the receiving part 6 in the second position and of signalling that the second position has been reached is also provided. This means comprises detents 87,88 (FIGS. 15,20-22, 33-34) in the support surfaces 57,58.

(68) The ends 30,31 of the alignment ridges 28,29 supported by the support surfaces 57,58 engage the detents 87,88 in the second position. The weight of the cartridge 2 holds the ends 30,31 in the detents 87,88. They are lifted out when the user pulls on the cartridge 2.

(69) It will be clear from the above description that the first ports 62-65 are placeable in sealed liquid communication with the cartridge ports 11-14 by placing the receiving part 6 with the inserted connecting head 9 in the second position. The valve mechanism comprising the receiving part 6 is then in an open configuration. Left and right ratio-setting valves can still be placed in a closed configuration in the second position in order to interrupt the flow of liquid from and to the cartridge 2.

(70) A left ratio-setting valve includes a left screening part 89, a left operating part 90, a left movable regulating part 91 and left valve sealing elements 92-94.

(71) The first ports 62,63 of the left ratio-setting valve are defined in a valve housing part 95 integral to the left screening part 89 (FIGS. 23-25), which is inserted through a left housing part aperture 96 (FIGS. 19-21) such that the latter is closed except for the first ports 62,63. In fact, the left screening part 89 lines a significant part of a side wall of the housing cavity in which the receiving part 6 is arranged to move between the first and second position, in this embodiment. This need not be the case in all embodiments.

(72) The movable regulating part 91 (FIGS. 29-31) is essentially disc-shaped. It is arranged for rotation in the left valve housing part 95. This valve housing part 95 defines an essentially cylindrical valve chamber. A planar surface 97 of the movable regulating part 91 (FIG. 31) faces the first ports 62,63 and is pressed against first and second left valve sealing elements 92,93 surrounding first and second first ports 62,63 respectively.

(73) An aperture 98 is formed through the movable regulating part 91. The aperture 98 is movable between positions of varying degrees of overlap with the first ports 62,63 by varying the rotary position of the movable regulating part 91. In at least one rotary position, the aperture 98 is in a position in which it does not overlap with any of the first ports 62,63, so that they are covered by the planar surface 97. This position corresponds to the closed configuration of the left ratio-setting valve.

(74) The left valve chamber is closed by the movable operating part 90 (FIGS. 26-28), which is arranged to support a third left valve sealing element 94. This sealing element 94 is pressed against the movable regulating part 91 and surrounds a second port 99 formed in the movable operating part 90. The movable operating part 90 is thus journalled for rotation about the second port 99 about an axis fixed to the left housing part 3. Teeth 100,101 on the movable operating part 90 engage gaps 102,103 in a circular ridge 104 on the movable regulating part 91 that faces the movable operating part 90. The movable regulating part 91 is thus coupled for rotation with the movable operating part 90. The movable operating part 90 is held in place by its circumferential edge, which is located between the left housing part 3 and the left screening part 89.

(75) Depending on the direction of flow, the second port 99 functions as the inlet or outlet of the head part 1. A conduit (not shown) can be connected to the second port 99 by means of an insert such as described, for example in EP 0 890 774 A1. The conduit may be a flexible conduit, for example.

(76) Assuming that the second port 99 forms the inlet, the incoming flow of liquid is split into two sub-flows in the ratio-setting valve. When the ratio-setting valve is not in the closed configuration, the volumetric flow rate ratio of the two sub-flows is determined by the rotary position of the movable regulating part 91 and the movable operating part 90. The user can set this position by hand by grasping and turning the movable operating part 90, even with the conduit connected. The ratio determines the composition of the liquid mix formed in the second bed 25 of the cartridge 2. The user can also move the movable operating part in a position in which the supply of liquid is cut off altogether.

(77) So as not to be tied to a particular direction of flow along the wall to which the head part 1 is mounted, the second port 99 of the left ratio-setting valve can also form the outlet. In that case, sub-flows of liquid are united in the left ratio-setting valve. The valve can for instance be set to a ratio of 1:1. Since the mixing of differently treated sub-flows of liquid already takes place in the second bed 25, the two sub-flows that then pass through the first ports 62,63 have the same composition.

(78) However, if the cartridge 2 includes a membrane module (not shown) for cross-flow filtration, then the left ratio-setting valve can be used as a mixing valve to add a certain amount of retentate received through one of the first ports 62,63 to filtrate received through the other of the first ports 62,63.

(79) In view of the reversibility of the direction of flow, the right ratio-setting valve is essentially a mirror image of the left ratio-setting valve. That is to say that it includes a right screening part 105, a right operating part 106, a right movable regulating part 107 and right valve sealing elements 108-110 (FIGS. 32-38). A second port 111 (FIG. 32) is formed in the movable valve operating part 106.

(80) The first ports 64,65 of the right ratio-setting valve are defined in the right screening part 105, which is inserted through a right housing part aperture 112 such that it is closed except for the first ports 64,65. The left and right screening parts 89,105 are mirror images of each other. Thus, the right screening part 105 includes an integral valve housing part 113 defining an essentially cylindrical valve chamber closed by the movable operating part 106.

(81) The regulating parts 91,107 and the operating parts 90,106 are identical.

(82) Where the second port 111 forms the outlet, the right ratio-setting valve can be used to cut off the flow of liquid through the liquid treatment apparatus in addition to or instead of the left ratio-setting valve whilst the cartridge 2 is in its operational position.

(83) The invention is not limited to the embodiments described above, which may be varied within the scope of the accompanying claims. A non-modular embodiment in which the first ports 62-65 are formed in the left and right housing parts 3,4 is also conceivable, for example. In that case, the valve housing parts 95,113 would be formed on the housing parts 3,4.

(84) In an alternative embodiment, the movable regulating parts 91,107 are actuated by an actuator comprised in an electromechanical system. The actuator may include an electric motor, for example. Such a system may be arranged to set the volumetric flow rate ratio automatically, e.g. based on values of a signal from one or more sensors. The system may alternatively or additionally comprise one or more sensors for detecting a fault in the liquid treatment apparatus such as a leak and be arranged to place the ratio-setting valve in the closed configuration on detection of the fault.

LIST OF REFERENCE NUMERALS

(85) 1head part 2cartridge 3left housing part 4right housing part 5mounting plate 6receiving part 7cap-shaped part 8vessel 9connecting head 10cartridge axis 111.sup.st cartridge port 122.sup.nd cartridge port 133.sup.rd cartridge port 144.sup.rd cartridge port 151.sup.st surface section 162.sup.nd surface section 171.sup.st channel 182.sup.nd channel 193.sup.rd channel 204.sup.th channel 21fall tube 22flow distributor device 23first bed of liquid treatment medium 24liquid-permeable divider 25second bed of liquid treatment medium 26concentric flow conductor 27liquid-permeable screen 281.sup.st alignment ridge 292.sup.nd alignment ridge 30rounded end of 1.sup.st alignment ridge 31rounded end of 2.sup.nd alignment ridge 321.sup.st curved surface section 332.sup.nd curved surface section 34first (lower) section of first alignment ridge 35first (lower) section of second alignment ridge 36second (upper) section of first alignment ridge 37second (upper) section of second alignment ridge 381.sup.st receiving part sealing element 292.sup.nd receiving part sealing element 403.sup.rd receiving part sealing element 414.sup.th receiving part sealing element 425.sup.th receiving part sealing element 436.sup.th receiving part sealing element 44receiving part reference axis 451.sup.st receiving part port 462.sup.nd receiving part port 473.sup.rd receiving part port 484.sup.th receiving part port 49first receiving part side wall section 50second receiving part side wall section 51first alignment groove 52second alignment groove 53first (lower) groove section of first alignment groove 54first (lower) groove section of sec-ond alignment groove 55second (upper) groove section of first alignment groove 56second (upper) groove section of second alignment groove 57left support surface 58right support surface 59left ledge 60right ledge 61bypass channel 621.sup.st first port 632.sup.nd first port 643.sup.rd first port 654.sup.th first port 66left planar surface 67right planar surface 681.sup.st guide protrusion 692.sup.nd guide protrusion 703.sup.rd guide protrusion 714.sup.th guide protrusion 721.sup.st guide 732.sup.nd guide 743.sup.rd guide 754.sup.th guide 76left gap 77right gap 78latching device 79left pawl 80right pawl 81left arm 82right arm 83left downward-facing facet 84right downward-facing facet 85left facet for engaging the receiving part 86right facet for engaging the receiving part 87left detent 88right detent 89left screening part 90left operating part 91left regulating part 921.sup.st left valve sealing element 932.sup.nd left valve sealing element 943.sup.rd left valve sealing element 95left valve housing part 96left housing part aperture 97planar surface on regulating part 98aperture in regulating part 99second port of left ratio-setting valve 100tooth on operating part 101tooth on operating part 102gap in circular ridge 103gap in circular ridge 104circular ridge 105right screening part 106right operating part 107right regulating part 1081.sup.st right valve sealing element 1092.sup.nd right valve sealing element 1103.sup.rd right valve sealing element 111second port of right valve 112aperture in right housing part 113part defining right valve housing