AU764167B2

AU764167B2 - Cartridge and device for treating liquids

Info

Publication number: AU764167B2
Application number: AU38022/00A
Authority: AU
Inventors: Detlev Weyrauch
Original assignee: Brita SE
Current assignee: Brita SE
Priority date: 1999-04-08
Filing date: 2000-03-03
Publication date: 2003-08-14
Anticipated expiration: 2020-03-03
Also published as: PL350825A1; DE19915829A1; IL145394A; WO2000061257A1; JP4530388B2; PL193661B1; JP2002540927A; DE19915829B4; IL145394A0; AU3802200A

Description

-I -1- A Cartridge and a Device for Purifying Liquids The invention relates to a cartridge for the purification of liquids flowing through the cartridge, having a cartridge upper portion which has at least one intake opening, having a sealing member and having a cartridge main portion with side walls and outlet openings, wherein a purification agent is kept in the cartridge main portion.

The invention also relates to a device for purifying liquids, having a supply container with a bottom in which an opening is arranged, and having a cartridge which is filled with purification agent and which can be brought into sealing engagement with the bottom of the container by way of sealing means.

The purification of liquids includes, amongst other things, cleaning, filtering, removal of bacteria, and alteration of flavour and smell. A cartridge of the kind mentioned in the introduction is known and consists, in other words, of a container with an intake sieve which has intake openings, and an outlet sieve. In known cartridges, for the purpose of purifying water a purification agent in granular form is kept between the cartridge upper portion with the intake sieve or intake opening, on the one hand, and between the outlet sieve, on the other hand. The agent in granular form is also known, e.g. in the form of an ion exchanger, activated carbon, minerals and mixtures of same. By using the device described hereinabove for the purification of liquids, liquids e.g. water, amongst others, are made sterile.

Known purification devices for water carry out purification by using a mixture of ion exchangers and activated carbon. Disposed in the bottom opening of the supply container of the known purification device is a circular edge which is preferably set inclinedly at an angle with respect to the vertical central axis of the supply container and therefore also with respect to the bottom opening. An outer edge of comparable inclination is located along the greatest circumference of the cartridge, and these inclined edges, or outer edges, act as sealing members. In the known devices and cartridges, they ensure that the water disposed in the supply container above the cartridge is expelled through the intake openings in the cartridge upper portion and through the purification agent. This known purification apparatus is driven by gravity, i.e. the height of the column of liquid is responsible for the pressure with which the liquid to be cleaned or purified is pushed from top to bottom through the purification agent in the cartridge.

It has been seen that the outer edge of the known cartridge, also referred to as a filter cartridge, is vulnerable as a radially outwardly acting sealing member. If a cartridge of this kind strikes against a machine part during the manufacturing process, or falls to the floor, this sealing member, that is to say the outer edge providing the greatest diameter of the cartridge, will certainly become damaged.

Grooves or channels in this sealing member produce a certain by-pass, so that the full sealing capacity is not provided. Known filter cartridges are made of polypropylene which can become permanently deformed by outward impact. Such channels which cause unsealing are of only subordinate importance with the decalcification of water, flavour-or smell enhancement of water, and similar treatments. Therefore, this unsealing could be readily accepted in the known purification devices.

Whether a radially acting element in the form of an o-ring made of rubber or another elastomer material is produced for a reciprocal sealing seat or whether two plastics surfaces of equivalent shape are pressed together, the sealing capacity is always largely optimised by the one member being twisted relative to the other. In the known case, the cartridge provided with the rotationally-symmetrical sealing member was let from above into the opening in a conical bottom, and then twisted slightly by hand. If the sealing capacity was then to be improved, then obviously the torsional forces had to be increased to give even better sealing by an o-ring disposed on the outside of the cartridge being pressed against an inner sealing ring disposed at the opening in the conical bottom.

However, with movements such as these, it was seen that even after being used a few times, i.e. afterremoval of the cartridge from the inlet funnel and subsequent insertion of a different, or newly filled, cartridge, the sealing members were damaged or even destroyed. Wear had the usual effect.

OBJECT OF THE INVENTION S20 It is an object of the present invention to substantially overcome or at least ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.

SUMMARY OF THE INVENTION The invention provides a device for purifying liquids, having a supply container with a bottom in which an opening is arranged, and having a cartridge which is filled with purification agent and which can be brought into sealing engagement with the bottom of the container by way of sealing means, wherein at the sides of the cartridge the sealing means have an annular, expandable sealing lip which projects from the bottom of an annular groove in the direction of the container bottom, and which, on the sides of the 30 container bottom, have an inner sealing ring which projects in the opposite direction, the diameter of which sealing ring is less than the diameter of the sealing lip.

The preferred embodiment provides a cartridge and also a device for purifying liquids, in such a way that the sealing means between the supply container and cartridge permit leakage-free operation and are mechanically protected even during a relatively long service life.

[R:\LIBD]03517.doc:caa 2a The cartridge according to the preferred embodiment is arranged on the side of the cartridge upper portion facing the cartridge main portion is an annular groove which is open away from the cartridge main portion, from the bottom of which annular groove a ring shaped or annular expandable sealing lip projects.

Both the cartridge as well as the purification device with a cartridge of the aforedescribed kind can be operated by gravity. However, the same measures for creating leakage-free sealing also apply for cartridges and purification devices which operate by pressure, wherein the liquid is pressed by means of a pump, or other propellent, through the cartridge and discharged through the outlet openings. However, in the case of a 1o pressure-operated system, the cartridge, but also the supply container, can also be arranged and operated at any angle to the vertical. The preferred embodiment covers all these instances of application. However, to understand the features according to the preferred embodiment, a gravity-operated purification device is described, wherein the central axis of the supply container and also the central axis of the cartridge are substantially vertical. In this case, the intake opening is disposed in the top of the cartridge upper portion, whilst the cartridge main portion with the side walls is arranged underneath, and the outlet openings are disposed at the bottom end of the cartridge. With this embodio.

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[R:\LIBDJ03517.doc:caa ment, the side of the cartridge upper portion facing the cartridge main portion is consequently the lower region of the cartridge upper portion, to which the cartridge main portion is secured. In this lower region of the cartridge upper portion an annular groove is arranged according to the invention which passes around the central axis of the cartridge along a plane. The central axis of the cartridge cuts through this plane vertically. The annular groove is open away from the cartridge main portion, that is to say in the direction of the cartridge upper portion or upwardly. If one imagines the cartridge with the outlet openings in front of it standing on the table, then one is looking into the upper open annular groove and onto the bottom thereof which is preferably flat and from which the expandable sealing lip, also annular, projects. If a view is taken in the direction of the central axis from top to bottom, then the free upper edge of the sealing lip is seen which is secured to the bottom of the annular groove.

The important advantage of the new sealing lip mainly consists in the protective space which is formed by the annular groove and in which the sealing lip is protected from external influences, impact and collision. The maximum diameter of the cartridge is in the region of the cartridge upper portion which faces the cartridge main portion. The sealing member therefore has a smaller circumference because it is disposed with its somewhat smaller diameter inside the annular groove. Its radial extent, or outer periphery, offers a relatively larger radial extent than that of the sealing lip. It is therefore evident that the sealing lip is mechanically protected. A cartridge according to the new invention can move in the direction of the opening annular groove, or in the direction of the projecting sealing lip, towards an .0 outer portion of corresponding structure, and be sealingly connected thereto. If the new cartridge according to the invention abuts on a machine part during manufacture, or if it falls to the ground, then impact to the cartridge occurs in the region of its maximum radial extent, and the outside periphery of the annular groove, at most, is damaged. The sealing member itself is protected against impact and similar effects.

Whereas with known cartridges in which the maximum radial extent was the annular sealing edge itself which increased to an even greater size as the volume of the cartridge increased, with the risk of corresponding damage, according to the invention the size of the diameter of the sealing lip is dependent S upon the maximum radial extent of the cartridge. The annular groove simply needs to be made.

broader or narrower accordingly. As a result of the sealing lip formed in the annular groove various shapes of cartridge according to the preferred embodiment can be provided without any risk of damage.

Although the groove is preferably in the form of a circular ring, and is called an "annular groove", any form of ring other than a circular ring is possible. Accordingly, the sealing lip can also follow a different base line from a circle, e.g. an oval, an ellipse, or a rounded polygon.

By virtue of the feature that the annular sealing lip is expandable, the great advantage of greater sealing force is achieved. When the new cartridge is inserted into an outer portion, e.g. into the opening in a container bottom, the new sealing lip expands. Up until now, sealing lips, if they were used with cartridges at all became flattened and mushroomed over. With known structures, a sealing ring on the outer portion was greater in diameter than a sealing lip, so that when these two parts of the envisaged construction were joined together the sealing lip became flattened and mushroomed over, resulting in buckling and bulging to the sealing lip. It will be appreciated that buckles and bulges are very problematic for seals in a sealing lip. A size or a force at which a buckle or bulge occurs cannot be defined by the design of the sealing lip. This lack of definition in the operating state often occurred even prematurely.

Since the new sealing ring according to the preferred embodiment is capable of expansion, if excessive force is applied the lip can obviously also become overstretched and tear. The resistance to tearing of a base material is, however, much better defined, so that according to the invention by structuring the shape and establishing specific sizes of the sealing lip, as well as by defining the desired base material, the point at which over-stretching and tears occur is reached at a very much later time. It has been found that using conventional and economically tenable measures, base materials and shapes for the closed ring of the sealing lip can be found, so that during operation a high sealing force is reached through expansion of the sealing lip.

It is advantageous according to the preferred embodiment if the annular groove is delimited radially outwardly by an 0 outer annular collar and radially inwardly by a lower frustoconical portion of the cartridge upper portion which faces the cartridge main portion. The frustoconical shape of the cartridge upper portion permits the arrangement of intake openings, -slits, or the like, for the liquid or for the escape of air or gases, if necessary. Therein, it is always possible for the liquid which is to be cleaned to flow out of the region above the sealing lip to the inside of the cartridge upper portion.

It shall be repeated that the preferred embodiment is being described primarily with reference to a gravity-operated system. Therefore, the terms, "top" and "bottom" are used. However, a different arrangement with a pressure-operated system is conceivable, wherein the afore-mentioned central axis of the cartridge can be set inclinedly or transversely to the vertical. Nonetheless, the remainder of this description will continue to refer to the upper portion of the cartridge upper portion when the portion facing the incoming liquid is meant, and vice versa.

It is also particularly expedient according to the preferred embodiment if the height of the sealing lip, as measured from the bottom of the annular groove in the direction of the projecting sealing lip, is less than the comparable height of the outer annular collar, and if the sealing lip is preferably designed so that it tapers away from the bottom of the annular groove in cross-section. The former feature serves to improve protection to the sealing lip. Nevertheless, the fundamental protective space is, however, already formed by the entire region above the annular groove, wherein the upper end of this region of protection is the upper edge of the afore-described bottom frustoconical portion of the cartridge upper portion. The cartridge upper portion could, for example, have a lower and also an upper frustoconical portion following on from it, i.e. two frustoconical portions of different diameter. The protective space is then disposed in the region of the outer periphery of the lower frustoconical portion and is delimited by the free upper edge of the relatively large annular collar. The second feature preferably applies to a different preferred embodiment, according to which the sealing lip is designed so that it .tapers way from the bottom of the annular groove in cross-section. In other words, the base of the sealing lip is broader than the width of the free upper edge of the sealing lip. Also, the height of the sealing lip is considerably greater than the width of the base of the sealing lip. As a result of the tapering crosssection of the sealing lip from the base or bottom of the annular groove to the top, the sealing lip is imparted with a varying deformation capability, whereby the sealing forces during operation can be defined with very great accuracy. The tapering design of the sealing lip is also advantageous from the manufacturing viewpoint since a tapering sealing lip produced by injection-moulding is easier to remove from the mould.

It is also favourable from the manufacturing viewpoint, if, according to the preferred embodiment the sealing lip is made from the same base material as the cartridge upper portion; or if the sealing lip consists of an elastomer material. A cartridge upper portion can be formed well from polypropylene. However, the elastomer materials known in injection-moulding technology can also be considered for producing the 20 cartridge as a whole or parts thereof.

,i o The preferred embodiment is also characterised in that movement means are provided on the cartridge upper portion for the purpose of moving the cartridge in the direction of its central axis relative to an outer por- S tion. This outer portion can, for example, be an opening in the bottom of a supply container. If, with a preferred embodiment, the cartridge according to the invention is to be brought into leakage-free engagement with such an outer portion, e.g. the inner edge of the opening, it is expedient if the cartridge is moved relative to this outer portion. During this movement, the cartridge is to be imagined as being inserted in the direction of its central axis, in the direction of the central axis of the outer portion; thus, with gravity-operating systems, from bottom to top. Preferred embodiments achieve this in combina- 30 tion with a rotational movement around the afore-mentioned central axis. By arranging movement means on the cartridge according to the invention, during specific actuation of the cartridge, an accurately defined movement can be achieved. As a result, the exact sealing force is achieved, and leakage-free sealing between the cartridge and a bottom opening in the container can be achieved even by unskilled persons.

With another advantageous embodiment of the invention, arranged in the outer annular collar, on at least one peripheral portion of the outer annular collar, as a movement means, is a guide groove which is set at an angle of inclination towards the plane of the bottom of the annular groove and which opens -6inwardly and radially. For example, if a view is taken from the centre towards the inside of the outer annular collar, then the radially inwardly open guide groove is seen which extends across part of the periphery of the outer annular collar to the inside thereof. If it is remembered that the entire periphery of the outer annular collar extends over 3600, then the peripheral portion corresponds to an angle of to 3300, preferably 60 to 1800, and particularly preferably to approximately 900; wherein, in the latter instance, four such peripheral portions and therefore also four such guide grooves can be provided.

If the bottom of the annular groove is considered as flat, then it is easy to imagine that the guide groove can be set at the afore-mentioned angle of inclination to that plane. As with a ramp, as a result of this design of guide groove in the outer annular collar, starting with a rotational movement the cartridge moves in the direction of its central axis, as discussed hereinabove. Translatory movement results in accordance with the slope or the size of the angle of inclination of the guide groove. In a downward direction (in the direction of the cartridge main portion) the guide groove is then delimited by a "lower ramp". Conversely, the guide groove is delimited upwardly by an "upper ramp".

It is also advantageous according to the preferred embodiment if arranged at the upper end, at a further spacing away from the cartridge main portion, of the guide groove is an insertion opening, and if arranged at the bottom, oppositely disposed end is a window which cuts through the entire thickness of the outer annular collar. The insertion opening serves to introduce a control projection on an outer portion, O20 against which the cartridge is to be rotated, and the window at the oppositely disposed end not only o permits a position of engagement so that the user can feel or hear the end state and sealing position o°O* by way of a snapping movement, but the user is also able to visually detect the control projection on the outer portion in the end position through the window from outside the cartridge.

The problem mentioned in the introduction is solved with the purification device in that at the sides of the cartridge the sealing means have an annular, expandable sealing lip which projects from the bottom of an annular groove in the direction of the container bottom, and which, on the sides of the container bottom, have an inner sealing ring which projects in the opposite direction, the diameter of which sealing ring is less than the diameter of the sealing lip. It is true that it can fundamentally be imagined with the so-called outer portion, here the container bottom with opening, that the so-called inner sealing ring has a greater diameter than the diameter of the sealing lip. Basically, whenever the cartridge moves into the container bottom sealing is possible. However, a flattening and mushrooming out movement then arises with the afore-described problem of buckles and bulges if the flattening and mushrooming out movement is too excessive, According to the preferred embodiment, it is therefore preferable if the diameter of the inner sealing ring, which is disposed at the inner edge of the container bottom, is less than the diameter of the sealing lip. During the rotational insertion of the sealing lip at the sealing seat of the inner sealing ring, the sealing lip is then forced to expand outwardly conditioned by the increase in size of diameter of the sealing lip.

The advantages of expansion of the sealing lip have already been described hereinabove, like the protective function, since the expandable sealing lip is protected in an annular groove of the cartridge.

The cartridge according to the preferred embodiment can also successfully be inserted very easily into such container bottoms by unskilled end users, without any special instruction. Hardly any damage is to be expected, even if the cartridge or supply container are not handled with care.

This is further assisted by the arrangement on the container bottom at a radial distance from the inner sealing ring, concentrically and adjacently thereto, of an outer securing ring of greater diameter than that of the inner sealing ring. This outer securing ring passes around the inner sealing ring at a distance therefrom, resulting in the formation of an annular groove which is open "downwardly" towards the cartridge. The outer securing ring protects the surface of the inner sealing ring which is in sealing engagement with the sealing lip. Preferably, this surface is spherical. However, a ramp slope is sufficient, so that when it is inserted into the groove between the inner sealing ring and the outer securing ring the sealing lip will be securely engaged in sealing manner.

The function of securing the container bottom to the cartridge is also important because according to another feature of the preferred embodiment arranged on the outer securing ring is at least one radially outwardly projecting cam of a size such that it is able to slide relative to a guide groove provided on the cartridge and in this latter. The afore-mentioned cam therefore sits on the container bottom, which is to be considered as stationary, and is inserted into the insertion opening in the guide groove by appropriate rotational movement of the cartridge, so that by engaging in the guide groove the cartridge is then pulled or pushed axially (in the direction of the central axis) by relative rotational movement with respect to the conical bottom; i.e. the cartridge is inserted or removed. The afore-mentioned lower ramp of the guide groove is then used for the purpose of taking the cartridge out, when this latter is moved down and away from the container bottom during rotational movement. The upper ramp correspondingly serves to fit the cartridge.

o* If, with another advantageous embodiment of the preferred embodiment, the groove between the inner sealing ring and the outer securing ring is bridged in the region of the protecting cam by a supporting rib, then the S- cam is well supported against the outer securing ring and is held rigid relative to the container bottom.

S'"i The cam can preferably be characterised by a key colour, and then when the window is reached at the bottom end of the guide groove it is clearly visible from the outside in the sealing end position.

Arranging the cam radially outwardly on the outer securing ring is also advantageous because of the good cleaning possibility this offers. The container bottom, or the outer securing ring thereof with the cam, is subjected to less wear than a cartridge which has to be removed when the purification agent -8has been used up and which has to be replaced by a new one or refilled again. However, it is favourable if the material of the cam and of the outer securing ring is stable and of expedient shape. The afore-described guide groove is obviously of somewhat more complex shape than a cam, and is therefore also more difficult to clean. However, since the cartridge is changed anyway after its treatment agent has been used up, the accumulation of undesirable particles in the guide groove is less critical than at the location of the outer securing ring. This latter is considerably easier to clean.

The shape of the cam at the outer securing ring can be that of a knob, a semi-sphere or other projection. An elongate shape of cam is particularly favourable, wherein the longitudinal extent of the cam extends in the peripheral direction of the outer securing ring. Therein, the length should be selected in such a way that the cam always fits into the insertion opening; accordingly also fits through the window. The elongate shape serves to stabilise the cam and also offers the advantage that the cartridge can be rotated relative to the container bottom with less expenditure of force. The material used for the cartridge can be polypropylene, for example. Both the cartridge main portion as well as the cartridge upper portion can be made from this material by injection-moulding. A radial securing flange can extend at the upper end of the cup-shaped main portion of the cartridge, and be connected to the cartridge upper portion at the lower side of the bottom of the annular groove. This type of manufacture is simple and economical.

20 By virtue of the afore-described features according to the preferred embodiment, a large sealing force between the sealing members can be obtained, on the one hand, and the sealing lip is not only protected from outer mechanical forces, but is saved from friction and other claims, on the other hand. A few movements of pg..

the sealing surfaces are sufficient.

In this way, a leakage-free, 100% sealing between the space in the supply container for the liquid to be treated, on the one hand, and between the space under or outside the cartridge and also inside the cartridge, on the other hand, is ensured. The purification agent is able to keep out bacteria or destroy them, so that germ-free liquids can be produced.

30 If the ramp of the guide groove is of a suitable height, user-friendly forces can be provided, by means of which the sealing engagement is obtained, or the cartridge is able to be released from the sealing engagement.

p, Further advantages, features and possible applications of the present invention will emerge from the following description of a preferred embodiment in conjunction with the accompanying drawings, wherein: -9- Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 is a view in perspective, and broken away, at the top, of a supply container with a bottom and an opening disposed therein, and, at a spacing underneath it likewise broken away for the sake of clarity a cartridge, is a view in plan of the cartridge, wherein the thick black circular line denotes the sealing lip at the top, shows the development of a peripheral portion of the outer annular collar which corresponds substantially to an angle of 900, is a broken away sectional view along the line IV-IV of Figure 3, is a broken away sectional view along the line V-V of Figure 3, and is a sectional representation along the line VI-VI of Figure 3, wherein a part of the cartridge is also shown broken away.

The cartridge shown in Figure 1 and denoted generally by the reference numeral 1 consists of a cartridge upper portion 2 and the cartridge main portion 3 arranged thereunder.

Shown at a spacing from the cartridge 1 at the top in Figure 1, is a supply container 4 with a bottom and an opening 6 disposed therein. The cartridge 1 shall be described first of all. The cartridge main portion 3 thereof is cup-shaped and has outlet openings, e.g. an outlet sieve, at the bottom thereof, at the side not visible in the drawings. It can be imagined that a purification agent, e.g. an ion exchanger in granular form possibly mixed with activated carbon, is kept in the cartridge main portion 3. The intake opening in the cartridge upper portion 2 is not shown, either. It can be in the form of a plurality of intake slits arranged in a ring-like formation. The width of the slits is less than the minimum external dimension of the granular material, so that the granular material is retained by the outlet sieve, not visible, on the one hand, and by the intake opening, not shown, on the cartridge upper portion, on the other hand.

Placed at the upper end of the cartridge main portion 3 is a radially outwardly extending fixing flange 7 which can be seen in Figures 1 and 6. The upper side of this fixing flange 7 which passes circularly around the cartridge main portion 3 is a flat surface. Supported thereon by way of its lower bottom 8, which is likewise annular and faces the cartridge main portion 3 is the cartridge upper portion 2, and it is welded sealingly along this surface. This trace of a weld is characterised in Figure 6 by the reference numeral 9.

The cartridge upper portion 2 with its sealing means which is able to engage sealingly, in leakage-free manner, with the corresponding companion sealing means on the container bottom 5 is of particular benefit in the invention. The cartridge upper portion 2 consists of a lower frustoconical portion which is greater in diameter than the dome 12 which is placed over the annular wall 11. Facing the cartridge main portion at the lower edge of the frustoconical cartridge upper portion 2 is the bottom 8 of the annular groove which is denoted generally by the reference numeral 14. The bottom 8 is substantially flat and is disposed in parallel relationship with the fixing flange 7. This plane which is formed by the bottom 8 of the annular groove 14 is perpendicular to the central axis 13. In the embodiment shown here in the drawings, the supply container 4 with its opening 6 and the cartridge 1 are rotationally symmetrical to this same central axis 13. The annular groove 14 is delimited radially outwardly by an outer annular collar 15. A concentric, expandable sealing lip 16 which is also annular projects from the bottom 8 of the annular groove 14 between the lower frustoconical portion 10 of the cartridge upper portion 2 and the outer annular collar 15. From the drawings it can be seen that the sealing lip 16 is designed so that it tapers upwardly away from the bottom 8 of the annular groove 14. The annular groove 14 is open upwardly, i.e. away from the cartridge main portion 3. The sealing lip 16 can be arranged in the centre or to one or other of the sides in the annular groove 14. From Figure 2 it can be seen that the sealing lip 16 is arranged closer to (at a smaller spacing from) the outer annular collar than the lower frustoconical portion 10 of the cartridge upper portion 2.

On the basis of Figure 4, it can be seen that the projecting sealing lip 16 is of smaller height h than the outer annular collar 15. In the sectional view of Figure 4, the annular collar is admittedly thinner than at positions V and VI of Figures 5 and 6, but the height ratio of 1:2 still prevails.

Movement means are provided on the cartridge 1: a guide groove 17 is arranged in the outer annular collar 15. The base of the groove is the remaining outer wall of the outer annular collar 15. The guide groove 17 is open radially towards the inside. This can be seen clearly in Figure 1, where, as a result of the broken away portions of the cartridge 1 a view can be seen inside onto the outer annular collar i.e. onto the guide groove 17. Figure 3 shows a development in the paper plane of the outer annular collar 15 across the peripheral portion shown in that drawing. The observer is seated, so to speak, between the sealing lip 16 and the outer annular collar 15. If a view is taken in the direction of the central axis 13 from the top to the bottom onto the cartridge 1, then a broken line 21 in Figure 2 along an arc of the circle indicates the location of the section or the position of the person looking at the section of Figure 3. The bottom 8 of the annular groove is shown in section, and the annular inside surface of the outer annular collar 15 is shown substantially over a quarter of the periphery of the circle of the annular collar From Figure 2 it can be seen that the periphery of the outer annular collar 15 is divided into four portions, so that each peripheral portion corresponds to approximately 90 0 The development shown in Figure 3 is disposed inside this 900 four times. Therefore, in describing the invention, it will be sufficient simply to show and describe one peripheral portion corresponding to an angle of 90 0 The other three peripheral portions of the annular collar 15 are of the same design.

-11 The guide groove 17 which is open inwardly towards the observer and towards the central axis 13 is set an angle of inclination p3 relative to the plane of the bottom 8 of the annular groove 14. It can therefore be seen that the insertion end, shown to the left of Figure 3, of the guide groove 17 is higher and therefore further away from the bottom 8 of the annular groove 14 than the oppositely disposed righthand retaining end or engagement end of the guide groove. At this latter end, it is possible to look through a window 18 through the outer annular collar 15, that is to say to look radially to the outside.

This can also be seen in Figure 1 at the location of the window 18 in the annular collar 15. In the region of this window 18, the guide groove 17 is without a bottom. Instead, the window passes through the entire thickness D (Figure 6) of the outer annular collar 15. The guide groove 17 with an insertion opening 19 starts at the upper end which is at a greater distance away from the cartridge main portion 3. It is of a funnel-like configuration with two lateral spherical faces 20 which are shown as inclined intake surfaces 20 to illustrate an alternative embodiment. The embodiment of Figure 3 can also be seen in the direction in which the central axis 13 is viewed in Figure 2. In that drawing, a relatively wide spherical intake surface 20 can be seen, followed by the insertion opening 19, and rotating anticlockwise a thinner intake surface 20. The guide groove 17 starts practically underneath the thinner intake surface, or intake slope 20, next to the portion indicated by a broken line in Figure 2, and ends at the window 18.

Figure 3 shows three sectional views, by means of which the construction of the guide groove 17 can be further clarified in conjunction with Figures 4 to 6. Figure 4 corresponds to the sectional line IV-IV of Figure 3. Parallel to the outer annular collar 15, the insertion opening 19 is open from the top to the bottom, as far as the lower ramp 22 of the guide groove 17. However, the person looking at Figure 3 does not see the sealing lip 16 which is arranged radially further towards the centre (central axis 13).

The observer sees only the outer portion which is denoted generally by the reference numeral 23 and which is shaded from top right to bottom left in Figures 4 and 6.

The sectional view of Figure 5 is a section along the line V-V of Figure 3. The guide groove 17 is shown clearly here by two horizontal broken lines. The guide groove 17 is disposed between them.

Outside the lower ramp 22 it is possible to see the upper ramp 24 as well. The lower ramp 22 likewise belongs to the bottom 8 of the annular groove 14. Disposed between the radially outer end (to the left in Figures 4 to 6) of the lower ramp 22 and a portion 15' of reduced thickness of the annular collar 15 it is possible to see a slit 25 which simply improves removal from the mould during the manufacture of the plastics members by injection-moulding.

The sectional view of Figure 6 is taken through the window 18. It can be seen that the distance of the lower ramp 22 from the lower surface of the bottom 8 of the annular groove 14 becomes less gradually from position IV through position V to position VI. This corresponds to the angle of inclination p of the -12guide groove 17 which extends from the insertion opening 19 in Figure 3 to the right: downwardly closer to the bottom 8.

All portions in contact with the guide groove 17 as movement means are to be seen at the side of the cartridge, in particular at 17 to 20, 22 and 24.

Sealing means at the bottom 5 of the supply container 4 cooperate with these sealing means at the side of the cartridge.

The opening 6 in the container bottom 5 has already been described with the aid of Figure 1. Extending in the direction of the central axis 13, on the inner circular edge of the opening 6 is an inner sealing ring 26 which is reproduced in Figures 4 to 6, in particular. In these drawings, the bottom 5 of the container 4 is shown to be broken away. The radially innermost lip thereof is the inner sealing ring 26 which projects downwardly in the direction of the container bottom 5 and in the direction of the central axis 13. From the drawings, it can be seen that the diameter of the inner sealing ring 26 in this embodiment is smaller and at most equal to the diameter of the sealing lip 16. In this way, the uppermost and radially innermost edge 27 of the sealing lip 26 is able to come into linear contact with the spherical sealing surface 28 of the inner sealing ring 26, and finally come into sealing engagement, as shown by the state in Figure 6. If one moves away from the states of Figures 4 and 5 to those of Figure 6, the slight shift of the sealing lip 16 is evident with its increase in diameter. In other words, the sealing lip 16 expands.

If the state of the purification device of Figure 1 is studied, before the cartridge 1 is placed on the supply container 4 and sealingly connected to this latter, then it can be seen that the expandable sealing lip 16 projects upwardly from the bottom 8 of the annular groove 14 in the direction 29 of the central axis 13, whilst conversely at the side of the container bottom 5 the inner sealing ring 26 projects in the opposite direction 30, that is to say downwardly in the direction of the central axis 13. The directions 29 and 30 are disposed parallel to the central axis 13 and parallel to each other.

At a radial spacing a from the inner sealing ring 26, concentrically to this latter, and also adjacent to this latter, there is an outer securing ring 31 which is greater in diameter than the sealing ring 26 on the container bottom 5. As a result, both the inner sealing ring 26 as well as the outer securing ring 31 which is disposed at a distance therefrom extend in the direction 30 of the bottom 5 towards the cartridge, and a groove 32 is formed which is open downwardly in the direction Arranged on the outer securing ring 31 are four radially outwardly projecting cams 33. Each of these cooperates with one of the four guide grooves 17. In describing the invention, it will suffice to describe just one pair of the movement means, namely a cam 33 and a guide groove 17.

-13- The sections according to Figures 4 to 6 are taken at the bottom, always straight through the cam 33.

This latter is of a depth and length such that it fits into the insertion opening 19, on the one hand, and is S able to pass partly through that insertion opening on reaching the position of the window 18, on the other hand, as can be seen from the position in Figure 6. In this way, the outwardly marked cam 33 is visible even from the outside of the outer annular collar 15 in the locking- or retaining position which also corresponds to the sealing position (Figure 6).

The groove 32 between the inner sealing ring 26 and the outer securing ring 31 is bridged in the region of the projecting cam 33 by a supporting rib 34. The supporting rib 34 can be seen in Figures 4 to 6 since the section is taken in the line of view "in front of" the centre of the cam 33.

During operation, the initial state is that shown in Figure 1. The user simply needs to pass the four cams 33 through the four insertion openings 19 and then to rotate the cartridge 1 relative to the bottom 5, considered to be in a stationary state, of the supply container 4. If a view is taken from above in the direction of the arrow 30 onto the cartridge 1 through the opening 6 in the bottom 5, then the cartridge 1 is rotated anti-clockwise, thereby causing the respective cam 33 to slide under the sloping guide groove 17. About half-way up the height, the position V is reached. In Figure 5, it is possible to see the cam 33 engaging under the outer annular collar 15, i.e. under the upper ramp 24. Radially further inwardly, in Figure 5, it is possible to see the way in which the uppermost inner edge 27 of the sealing lip 16 comes into direct pressure contact with the spherical face 18 of the inner sealing ring 26, and comes into a bent position. The sealing lip 16 starts to expand. If the user continues to rotate the cartridge 1, then the cam 33 slides further down and to the right in the guide groove 17, until the window 18 is reached and the cam 33 is retained therein. This state is shown in Figure 6. Radially further inside, it is possible to see the expanded sealing lip 16 which has then engaged in leakage-free sealing engagement with the spherical surface 28 of the inner sealing ring 26.

The release operation is carried out in reverse.

-14- List of Reference Numerals 1 Cartridge 2 Cartridge Upper Portion 3 Cartridge Main Portion 4 Supply Container Container Bottom 6 Bottom Opening 7 Fixing Flange 8 Bottom of Cartridge Upper Portion 9 Weld Seam Lower, frustoconical Portion of the Cartridge Upper Portion 11 Annular Wall 12 Dome 13 Central Axis 14 Annular Groove Outer Annular Groove 16 Sealing Lip 17 Guide Groove 18 Window 19 Insertion Opening Lateral Intake Surfaces 21 Sectional Line indicated by a Dotted and Dashed Line 22 Lower Ramp 23 Outer Portion 24 Upper Ramp Slit 26 Inner Sealing Ring 27 Inner Edge 28 Sealing Surface 29 Direction of Sealing Lip Upwardly (Towards the Central Axis) Direction of Sealing Lip Downwardly (Towards the Central Axis) 31 Fixing Ring 32 Groove 33 Cam 34 Supporting Rib

Claims

1. A device for purifying liquids, having a supply container with a bottom in which an opening is arranged, and having a cartridge which is filled with purification agent and which can be brought into sealing engagement with the bottom of the container by way of sealing means, wherein at the sides of the cartridge the sealing means have an annular, expandable sealing lip which projects from the bottom of an annular groove in the direction of the container bottom, and which, on the sides of the container bottom, have an inner sealing ring which projects in the opposite direction, the diameter of which sealing ring is less than the diameter of the sealing lip. t0

2. A device according to claim 1, wherein the cartridge is provided for the purification of liquids flowing through the cartridge, having a cartridge upper portion which has at least one intake opening, having a sealing member and having a cartridge main portion with side walls and outlet openings, wherein a purification agent is kept in the cartridge main portion, and on the side of the cartridge upper portion facing the cartridge main portion an annular groove is arranged which is open away from the cartridge main portion, from the bottom of which annular groove an annular expandable sealing lip projects.

3. A device according to claim 1 or 2, wherein the annular groove is c: delimited radially outwardly by an outer annular collar and radially inwardly by a lower frustoconical portion of the cartridge upper portion which faces the cartridge main portion.

4. A device according to any one of claims 1 to 3, wherein the height of the sealing lip, as measured from the bottom of the annular groove in the direction of the projecting sealing lip, is less than the comparable height of the outer annular collar, and it is preferably designed so that it tapers away from the bottom of the annular groove in cross-section. S.

5. A device according to any one of claims 1 to 4, wherein the sealing lip is made of the same base material as that of the cartridge upper portion or consists of an elastomer material. *S.S

6. A device according to any one of claims 1 to 5, wherein movement means are provided on the cartridge upper portion for the purpose of moving the cartridge in the direction of its central axis relative to an outer portion.

7. A device according to any one of claims 1 to 6, wherein arranged in the outer annular collar, on at least one peripheral portion of the outer annular collar, as a [R:LIBD]03517.doc:caa -16- movement means, is a guide groove which is set at an angle of inclination towards the plane of the bottom of the annular groove and which is open inwardly and radially.

8. A device according to any one of claims 1 to 7, wherein arranged at the upper end, at a further spacing away from the cartridge main portion, of the guide groove is an insertion opening, and arranged at the bottom, oppositely disposed end is a window which cuts through the entire thickness of the outer annular collar.

9. A device according to claim 1, wherein arranged on the container bottom, at a radial distance from the inner sealing ring, concentrically and adjacently thereto, is an outer securing ring of greater diameter than that of the inner sealing ring.

10. A device according to claim 1 or claim 9, wherein arranged on the outer securing ring is at lest one radially outwardly projecting cam of a size such that it is able to slide relative to a guide groove provided on the cartridge and in this latter.

11. A device according to any one of claims 1, 9 or 10, wherein the groove between the inner sealing ring and the outer securing ring is bridged in the region of the Is projecting cam by a supporting rib.

12. A device for purifying liquids substantially as hereinbefore described with reference to the accompanying drawings. Dated 5 June, 2003 20 Brita GmbH o Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\LIBD]03517.doc:caa