WARM LIQUID DISPENSING SYSTEM

This invention relates to a warm liquid dispensing system and relates particularly, though not exclusively, to a warm water hand washing system for bathrooms or washrooms.

Hand washing requires a water source delivering warm water at a temperature of around 37 ⁰ C to 40°C. It is unacceptable to store water at this temperature in view of the danger from Legionella bacteria. The bacteria will grow at temperatures of between 20.5 ⁰ C and 50°C, with the optimal temperature range for growth between 35 ⁰ C and 46°C. The Legionella bacteria cannot survive in water above 55°C for more than five or six hours but will be instantaneously destroyed at 70°C and above. In typical bathrooms, hands are washed by either manipulating a hot and cold tap, or guessing the correct setting for a mixer tap. The water will scold the user, if the water is too hot or be too cold. The hot water will typically be delivered by a pressurised hot water service which must include an expansion chamber or pressure relief valve. If an expansion chamber is used, the system requires the expansion chamber to be emptied to prevent overflow. A vent to the expansion chamber is also required which normally discharges at the tap outlet, in case the expansion chamber becomes full.

It is an object of the present invention to provide a warm liquid dispensing system requiring no expansion chambers or pressure relief valves.

A further object of the invention is to provide a warm liquid dispensing system which can deliver liquid at a non-scolding temperature. A still further object of the invention is to provide a warm liquid dispensing system where the hot water is not pressurised.

With these objects in view the present invention provides a warm liquid dispensing system including an unpressurised hot liquid supply, a first pressurised cold liquid supply, a venturi mixer having its pressure inlet coupled to said first pressurised cold liquid supply and its suction inlet coupled to said unpressurised hot liquid supply, a dispensing device coupled to the outlet of said venturi mixer, said dispensing device co-operating with a first flow control

valve associated with said first pressurised cold liquid supply to allow the dispensing of warm liquid from said dispensing device when said first flow control valve is actuated.

Preferably said unpressurised hot liquid supply includes a tank which includes a heating means to heat the liquid contained therein. It is preferred that a first temperature sensor is located within said tank to limit the temperature of the liquid contained therein. The temperature can be controlled by a controller and is preferably kept at 65°C to 95°C, and more preferably at

80°C. In a practical embodiment said tank is vented through a condenser and said vent preferably includes a float valve to prevent expulsion of hot liquid through said condenser if the level of liquid in said tank should exceed a predetermined level. Preferably said tank includes an inlet from a second pressurised cold liquid supply to allow cold liquid to enter said tank under the control of a level sensor contained therein. Preferably said level sensor allows actuation of a second flow control valve coupled to said second pressurised cold liquid supply.

In a further embodiment a second temperature sensor monitors the temperature of the warm liquid from said venturi mixer and is linked to said controller to override said first temperature sensor. Preferably the warm liquid dispensing system provides warm water for hand washing and said dispensing device is a tap or faucet.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate an especially preferred embodiment of the invention. In the drawings:

Fig. 1 is a cross-sectional schematic view of a warm liquid dispensing system made in accordance with a first aspect of the invention;

Fig. 2 is an enlarged view of the top of the warm liquid dispensing system shown in Fig. 1 showing condensation of vapour back to the warm liquid dispensing system;

Fig. 3 is an enlarged view of a part of the warm liquid dispensing

system shown in Fig. 1 showing liquid flow path; and

Fig. 4 is a similar view to that of Fig. 3 showing failure of the hot liquid level sensor.

In Figs. 1 to 4 there is shown a warm liquid dispensing system in the form of a warm water hand washing system 10 for bathrooms or washrooms. The washing system 10 is adapted to be connected to a pressurised cold water source at connection 12 of flow control valves 14, 16. Flow control valves are typically solenoid actuated and are coupled to an electronic controller 15 or other suitable control means. Water from flow control valve 14 flows along pipe 18 to the pressure inlet of venturi mixer 20. Venturi mixer 20 has a flow restriction 21 and hot water is drawn from pipe 22 when cold water flows along pipe 18. The cold and hot water are mixed within the venturi mixer to provide warm water, typically at 37 ⁰ C to 40°C to pipe 28. The amount of hot water drawn into pipe 22 is controlled by a variable flow valve 24. Valve 24 in this embodiment is adjustable through a needle valve 26 through screw control. The type of valve 24 is not restricted to the valve shown as other types of valves could be used, as would be obvious to the man skilled in the art. The temperature of the warm water in pipe 28 is monitored by a temperature sensor 30 and the water flows through pipe 34 which terminates at a tap or faucet 36. Tap or faucet 36 is secured to a basin, sink or bench top 38.

The system 10, except for tap or faucet 36 is contained within a casing 40 which can be mounted under the basin, sink or bench top 38 or in a wall cavity. A tank 42 which can be of any shape is mounted within casing and is connected to a cold water pipe 44 from flow control valve 16. The water 50 inside tank 42 is heated by a heating element 46 which is connected to controller 15. A temperature sensor 48 is also connected to controller 15 and maintains hot water 50 at a temperature of 65°C to 95°C, typically 80°C. By holding the temperature at 8O ⁰ C, the danger of Legionella bacteria breeding in the water is avoided. Valve 24 is located above temperature sensor 48 to ensure that only hot water is drawn therethrough. A water level sensor 52 is provided at the top of tank 42 and will maintain a constant level of water via feedback to controller 15 and flow control valve 16.

Tank 42 is vented to the atmosphere through outlet 64 of condenser 62 which is connected to the top of tank 42. As the tank 42 is not under pressure, a flat sided, light weight construction is possible. This will reduce costs and enable tank 42 to fit in a confined space, for example, a wide fiat tank could be fitted inside a wall cavity. Condenser 62 has a float valve 54 which prevents hot water escaping through condenser 62, if the water level sensor 52 fails, as shown in Fig. 4. Float valve 54 has a float 58 which, in normal use, sits on a support 56. If water level sensor 52 fails then float 58 will rise and seal off valve seat 60 to prevent escape of hot water through condenser 62. Operation of the warm water hand washing system 10 will now be described. Controller 15 is calibrated to have the hot water 50 in tank 42 maintained at around 80°C or other suitable temperature. Temperature sensor 48 will monitor the temperature and allow controller 15 to activate heating element 46 as required. Water level sensor 52 will typically maintain an air gap of around 25mm at the top of tank 42 through controller 15 and flow control valve 16. The volume of hot water 50 which can leave tank 42 is controlled by variable flow valve 24. This volume can be adjusted manually by turning needle valve 26 or having an electrically operable valve adjusted by controller 15. If water level sensor 52 fails, or controller 15 fails, or flow control valve 16 cannot be turned off, then float 58 will rise and seal off valve seat 60 to prevent escape of hot water through condenser 62.

When tap or faucet 36 is turned on, a sensor or switch (not shown) will cause controller 15 to turn on flow control valve 14. The flow of water along pipe 18 into venturi mixer 20 will cause hot water 50 to be drawn through variable flow valve 24 into pipe 22 to be mixed with the cold water from pipe 18. The warm water passes through pipe 28 and its temperature is monitored by temperature sensor 30. Temperature sensor 30 provides feedback to controller 15 to adjust the temperature of hot water 50 as required. The warm water typically issues from tap or faucet 36 at a comfortable temperature of 37°C to 4O ⁰ C which will not scold the user's hands. As the warm water is drawn, water level sensor 52 will, through controller 15, open

flow control valve 16 to refill tank 50. If required, a plurality of taps or faucets 36 can be attached to pipe 34.

Fig. 2 illustrates the operation of condenser 62. Water vapour 66 can rise through float valve 54 and will condense as droplets 68 as shown to return to tank 42. The length of condenser 62 is sufficient to prevent venting of water vapour through outlet 64.

The invention provides a simple to use system which provides a uniform water temperature and can be conveniently fitted in small places. As the tank 42 is vented, as opposed to being under pressure, the system is very safe and exposure to steam is avoided. Although the embodiment has been described with reference to use in bathrooms and washrooms, the invention is not limited to such use.

The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and a certain specific embodiment thereof by way of example.

MOUNTING SYSTEM This invention relates to a mounting system and relates particularly, though not exclusively, to a tap mounting system for bathrooms or washrooms.

The installation of tap ware for basins can be difficult to install in view of the confined space underneath the basin. The installation usually involves; feeding tubing attached to the tap through a hole provided in a bench, sink or basin. A clamping device, typically a nut, clamp or bracket must then be fitted to the underside of the tap ware. This usually requires the installer to reach up behind the sink or basin and either, working by feel or lying face up inside the cupboard area to fit, align and tighten the nuts, screws, brackets, etc. It is a time consuming matter and can result in injuries in view of the awkward positioning of the installer's body to undertake the work.

It is an object of the present invention to provide a mounting system whereby a tap or faucet may be fitted and tightened from above a bench, sink

or basin without an installer having to reach up from underneath to tighten nuts, screws or clamps.

A further object of the invention is to provide a mounting system which is simple and quick to use to install affix a tap or faucet to a bench, sink or basin.

With these objects in view the present invention provides a mounting system for allowing coupling of a member to one side of a wall member through an aperture in said wall member, said mounting system including a tubular member having at least one resilient finger at one end and a threaded section at the other end, said at least one resilient finger including a protuberance which abuts the other side of said wall when pushed through said aperture to prevent unintended withdrawal of said tubular member through said aperture and a threaded member adapted to cooperate with said threaded section to fasten said mounting system to said wall member. Preferably a plurality of said at least one finger are provided. A bearing member is preferably located between said threaded member and said one side of said wall member, and said bearing member has said member coupled thereto. In a preferred embodiment said bearing member includes a peripheral groove for the location therein of at least one lug attached to said member. In a further embodiment said bearing member includes a further groove which limits the rotation of said member about said bearing member when an engagement member on said member is located therein.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate an especially preferred embodiment of the invention. In the drawings:

Fig. 5 is a cross-sectional view of a mounting system made in accordance with the invention;

Fig. 6 is an exploded disassembled view of the mounting system shown in Fig. 5;

Fig. 7 is a perspective view of the mounting system shown in Fig. 1 on a bench prior to tightening; and

Fig. 8 is a similar view to that of Fig. 7 showing the mounting system attached to a sink and being tightened.

In Figs. 5 to 8 there is shown a mounting system 100 which, in this embodiment, is directed to a plumbing fixture. The mounting system 10 can be secured to a bench ] 02, typically 45m in depth, or to a stainless steel sink 104 as shown in Fig. 8, typically lmm in depth. The system is flexible to allow its use with any depth of wall thickness. The system allows a tap, faucet or other water outlet 106 to be secured to bench 102 or sink 104. The construction of the tap 106 will not be further described as the invention is applicable to any such fixture. Tap 106 may include tubing 108, 1 10 for cold and hot water and may contain wiring 1 12 for any required electrical connection, for example, switches or illuminating devices. The number and configuration of integers 108-112 can vary to suit the particular requirements of the fixture. A tubular member 1 14 is provided which has a threaded section 120 at one end and a set of resilient fingers 124 at the other end. The number and configuration of the fingers 124 can also vary for particular installations. At the end of each finger ] 24 is a wedge like protuberance 1 16 which has a flat abutment surface 1 18 facing the opposite side of bench 102. The tubular member 1 14 can be formed of any suitable material but a plastics material is preferred. At the other end of tubular member 1 14 there is a threaded section 120 and a groove 122 there along. In use, tubular member 1 14 is pushed through aperture 126 in bench 102. When wedge like protuberances 1 16 enter aperture 126 they are deflected inwardly to allow the protuberances 1 16 to slide down aperture 126 and emerge at the other end. Once released, the resilient fingers 124 will deflect outwardly and the flat abutment surfaces 1 18 of protuberances 1 16 will engage with the opposite surface of bench 102, as clearly seen in Fig. 5.

A tubular sleeve 130 is located within tubular member 1 14 and rests on shoulder 128 through flange 132. Sleeve 130 may be metallic and provides strength for tubular member 1 14, but may be omitted. A sealing gasket 134 sits on bench 134 and is positively located by a tongue 136 which cooperates with groove 122 on threaded section 120 of tubular member 1 14.

A bearing member 138 slides over the threaded section 120 of tubular member 1 14 and is seated on sealing gasket 134. A longitudinal tongue 140 is located on the inside of bearing member 138 and cooperates with groove 122 on threaded section 120 of tubular member 1 14 to prevent rotation of bearing member 138. An external flange 142 is located adjacent the bottom of bearing member 138 and provides a locating system for a decorative ring 144 which sits on sealing gasket 134. A groove 146 receives lugs 148 from the body of tap 106 which allows a guided rotation of the tap 106 about bearing member 138. Lugs 148 enter groove 146 through axially parallel further grooves 150. A circumferential groove 152 which covers an arc of about 45° will limit rotation of the body of tap 106 when grub screw 154 is inserted through the body of tap 106 to enter circumferential groove 152. A threaded nut 156 screws onto threaded section 120 to clamp bearing member 138 and decorative ring 144 to bench 102. Nut 156 can be of any suitable type, for example, hexagonal, or the shape as shown, requiring a spanner 158 to engage notches 160 in nut 156. If required, a wave washer 162 is located between a ledge 164 on tap 106 and nut 156 to provide a spring bias to lift tap 106 and allow lugs 148 to be pressed against the upper surface of groove 146 as shown in Fig. 5.

The assembly of the mounting system 10 and its use with a tap will now be described. Tubular member 114 is inserted into aperture 126 and the wedge like protuberances 1 16 will be deflected inwardly to allow the protuberances 1 16 to slide down aperture 126 and emerge at the other end. Once released, the resilient fingers 124 will deflect outwardly and the flat abutment surfaces 1 18 of protuberances 1 16 will engage with the opposite surface of bench 102, as clearly seen in Fig. 5. Tubular sleeve 130 is inserted into tubular member 1 14 and flange 132 rests on internal shoulder 128. Gasket 134 is then placed over tubular member 1 14 with its tongue 136 aligned with groove 122 and pushed onto bench 102. Decorative ring 144 is then placed in position to rest on gasket 134 and then bearing member 138 slides over tubular member 1 14 with its tongue 140 aligned with groove 122. Nut 156 is then loosely screwed to threaded section 120 of tubular member 1 14. Bearing member 138 is then correctly oriented with respect to groove 152 to define the

45° rotation limit of tap 106. Nut 156 is then screwed down tightly with spanner 158, as shown in Fig. 8. The excess length of threaded section 120 is then cut off with a cutting blade 166. The thickness of bench 102 or thickness of sink 104 will determine how much, if any, of threaded section 120 is removed. Accordingly, the mounting system 10 provides a one size solution which minimizes production of various sized tubular members. The tubing 108, 1 10 and wiring 1 12 can then be passed through tubular member 114 to the underside of bench 102 or sink 104 for connection to the relevant sources. Wave washer 162 is then placed on nut 156 and lugs 148 of tap 106 are aligned with grooves 150 to allow lugs 148 to be located within groove 146. Ledge 164 will then abut wave washer 162 and its resilient bias against nut 156 will cause lugs to frictionally engage the upper surface of groove 146 to prevent tap 106 from freely rotating. Finally, grub screw 154 is screwed into groove 152 to complete the assembly. From the above it is clear that the assembly does not require an installer to reach up under a basin or be lying face up inside a cupboard to complete the assembly. The assembly is quick and clean and does not require skilful dexterity to complete the assembly. The mounting system allows the tap to be rotated and the assembly is hidden inside the tap. If required, bearing member 138 may be threaded, allowing nut 156 to be omitted. Although the preferred embodiment has been described with reference to its use with plumbing fixtures the invention is not limited to that purpose. The invention may be used wherever a fitting is required to be attached through an aperture opening into opposing sides of a wall, for example, a vacuum cleaner connection or coupling for a meter.

The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and a certain specific embodiment thereof by way of example.

FILTER SYSTEM

This invention relates, in general, to a filter system for filtering a liquid and relates more particularly, though not exclusively, to a filter system for water. In known filter systems for water, a filter cartridge is screwed into a mounting arrangement under the sink. Such systems usually include a disposable filter which is dropped into a container having a screw thread at one end. The container is then screwed onto a mounting arrangement to complete the assembly thereof. Such arrangements are messy and difficulties can arise in removing the filter. The container has a tendency to stick and can be difficult to twist off. The arrangement also requires a substantial vertical clearance to enable the filter to be removed.

It is therefore an object of the present invention to provide a filter system which allows easier removal of the filter cartridge. A further object of the present invention is to provide a filter system which allows easy access to the filter cartridge.

With these objects in view the present invention provides a filter system for filtering a liquid, said system including a mounting bracket, a filter attachment bracket pivotally attached to the said mounting bracket, said filter attachment bracket having a coupling means to sealingly and releasably engage with the inlet and outlet of a filter cartridge having filtering media to remove contaminants from said liquid and at least one co-operating locking means on said mounting bracket and said filter attachment bracket to allow the said mounting bracket and said filter attachment bracket to be restrained when the filter system is in its operative position.

Preferably said mounting bracket includes at least one guide rail and said filler cartridge includes a co-operative guide slot to receive said at least one guide rail to form a further locking means. Preferably one of said at least one guide rail or said co-operative guide slot includes a lip and the other of said at least one guide rail or said co-operative guide slot includes a step and said lip engages with said step when said filter cartridge is in its operative position but can be disengaged therefrom in its non-operative position. Preferably said

at least one co-operating locking means may include at least one detent and a respective protuberance which engages therewith. Preferably said at least one co-operating locking means includes a ledge which is frictionally engaged underneath by a further ledge. In a preferred embodiment a plurality of differing co-operating locking means are provided. In a further aspect said coupling means is non-circular to prevent rotation of said filter cartridge. An electrical contact switch may be provided to allow a flushing cycle to occur when said filter cartridge is replaced and/or to lock off the liquid supply until said filter cartridge is correctly installed.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, in which:-

Fig 9a is a perspective view of a filter system made in accordance with a preferred embodiment of the invention and shown in its operative position;

Fig 9b is a similar view to that of Fig 9a but shows the filter cartridges being tilted;

Fig 9c is a similar view to Fig 9b but shows the filter cartridges being removed;

Fig 10 is a perspective exploded view of the components of the filter system of the preferred embodiment;

Fig 1 1 is a vertical cross sectional view through the filter system shown in Fig 9a; Fig 12 is a plan view of the filter cartridge used in this invention;

Fig 13 is a plan view of the filter attachment bracket used in the filter system of Fig 9a;

Fig 14a is a partial cross sectional view along and in the direction of arrows 14a-14a shown in Fig 1 1 ; Fig 14b is a similar view to that of Fig 14a but showing the filter cartridge tilted;

Fig 14c is a similar view to that of Fig 14b showing the filter cartridge being removed;

Fig 15a is a side view of Fig 1 1 shown in the position of Fig 14b; Fig 15b is a side view of Fig 11 shown in the position of Fig 14a; and

Fig 15c is a side view of Fig 11 shown with the filter cartridge under full pressure.

In the drawings there is shown an enclosure 210 which requires a filtering system 212 secured, or integrated, into enclosure 210. Enclosure 210 may include a cabinet for refrigerated water, a water cooler, drinking fountain or some other device requiring filtered water. In the embodiment shown, system 212 includes two filter cartridges 214, 216 which can be conventional filter cartridges. The number and type of cartridges can vary to suit the particular environment and contaminants to be removed. A lid 218 is coupled to the filter cartridge and is locked thereto by a snap fit, bayonet mount, screw thread or other type of coupling. Lid 218 could also be integrated into the design of the filter cartridges 214, 216. Lid 218 has an oval shaped protuberance 220 which has channels 222 for guiding contaminated water into a respective filter cartridge 214, 216 as clearly seen in Fig 1 1. The contaminated water will flow into the cartridge through inlet openings 224.

The contaminated water will flow through the filter media 226 and filtered water will exit via outlet 228. Outlet 228 co-operates with a bore 232 in lid

218 and the filtered water flows to exit nipple 230. Lid 218 has a pair of guide slots 234, 236 formed by a pair of inverted L-brackets 238. A pair of O-rings 240, 242 provide sealing to ensure that the contaminated water does not mix with the filtered water.

Filter cartridges 214, 216 co-operate with a filter attachment bracket 244 which is pivotally attached to axle 246 on mounting bracket 248. Bracket 244 has a shell member 250 which has an oval shape to match the oval shape of protuberance 220 of Hd 218 and is sealingly engaged therewith by O-ring 240. The oval shapes will prevent rotation of filter cartridges 214, 216 but such a shape is not essential. A bearing sleeve 252 is mounted on supports 254

attached to the top 256 of shell member 250. Bearing sleeve 252 receives axle 246 to allow bracket 244 to be pivotally mounted with respect to mounting bracket 48. An unfiltered inlet port 258 and a filtered outlet port 260 are axially aligned and are internally blocked by wall 262 which allows unfiltered water to move along passage 264 and through to channels 222 of lid 218. Wall 262 together with arcuate wall 266 forms a female coupling for sealingly engaging nipple 230 of lid 218. Cut-outs 268 in shell member 250 will engage over inverted L-shaped brackets 238.

Extending from bearing sleeve 252, at both ends thereof, are a pair of arm members 270 with protuberances 272 at their free ends. Protuberances 272 co-operate with respective detents 274, 276 in the side wall 278, 280 of mounting bracket 248. A pair of opposed curvilinear ledges 282, 284 provide an additional locking means by their frictional engagement under respective ledges 286, 288 attached to the inner faces of side walls 278, 280. Mounting bracket 248 has a top 290 and a rear wall 292, either of which can be secured to enclosure 210 through affixing holes 294. At the free ends of side walls 278, 280 are guide rails 296, 298 which slide under guide slots 234, 236 formed by inverted L-shaped brackets 238 on lid 218. Guide rails 296, 298 each have a step 297 at the rear thereof for engagement by respective lips 299 (Figs 15a-15c) underneath the inverted L-shaped brackets 238. Ledges 286, 288 are stepped at 300 to provide a stop for ledges 286, 288. Cut-outs 302, 304 are provided in side wall 278, 280 for reception of outlet port 260 and inlet port 258 respectively and further attachment bracket 244. An electrical switch 306 is mounted on side wall 280 and will have its plunger strike the exposed portion of inverted L-shaped bracket 238 of guide slot 236.

The operation of filter system 212 will now be described. The embodiment in Figs 9 and 1 1 shows the use of two filter cartridges 214, 216 but the invention can be used with a single cartridge or multiple cartridges. The unfiltered water enters filter system 212 through tubing 308 attached to the unfiltered inlet port 258 of filter cartridge 216 as shown in Fig 1 1. The water flows into passage 264 of filter attachment bracket 244, enters channels 222 of lid 218 and finally into inlet openings 224 of filter cartridge 216 as indicated by

th e flow arrows in Fig 1 1. The filtered water exits filter cartridge 216 through bore 232 of exit nipple 230 of lid 218 and out of outlet port 260. Tubing 310 links filter cartridge 216 to filter cartridge 214 to repeat the process.

The filter cartridges 214, 216 are locked into their operative position, as shown in Figs 9a, 1 1 , 14a and 15c, by three separate locking arrangements. Firstly, guide rails 296, 298 are located in guide slots 234, 236 to prevent the filter cartridges from being pulled from the locked position shown in Figs 9a, 1 1 , 14a and 15c. Lips 299 will engage with respective steps 297 as shown in Fig 15c to prevent accidental removal of filter cartridges 214, 216. Accordingly, filter cartridges 214, 216 cannot be tilted outwardly until the water supply is turned off. Secondly, lateral movement is prevented by ledges 282, 284 engaging underneath ledges 286, 288. The limit of pivotal movement of filter cartridges 214, 216 is restricted by the abutment of the ends of ledges 282, 284 against the stop formed by the step 300. Finally, protuberances 272 on arm member 270 engage detents 276 to divide positive feedback that the filter cartridges have been securely installed. The plunger of switch 306 will be depressed by its engagement with the inverted L-shape bracket 238 of guide slot 236 to activate the system. When a new filter cartridge is installed, switch 306 can indicate that the flushing cycle be commenced. Switch 306 can also ensure that the water supply from tubing 108 is shut off until filter cartridges 214, 216 have been correctly installed.

In order to change one or more of the filter cartridges 214, 216, the water supply through tubing 308 must be turned off, usually with a control valve (not shown). The release of water pressure in filter cartridges 214, 216 allows the filter cartridges 214, 216 to be able to be pushed upwardly slightly, as shown in Fig 15b. Lips 299 will be free of steps 297. It is then a simple matter to grasp the filter cartridge and tilt it outwardly from enclosure 10 as shown by the arrows in Figs 9b and 14b. A sufficient force will be required to overcome the three locking arrangements previously discussed. The correct position will be indicated by protuberances 272 engaging detents 274. Ledges 282, 284 will be free of ledges 286, 288, as will guide rails 296, 298 be disengaged from guide slots 234, 236. Filters 214, 216 can then be pulled from

filter attachment brackets 244 as indicated by arrows in Figs 9c and 14c. New filter cartridges 214, 216 can be installed in the reverse manner. At the completion of the installation of new filter cartridges 214, 216 they will be positioned as shown in Fig 15b. Lips 299 will be disengaged from steps 297. Once the control valve is turned on and switch 306 is activated, then a flushing cycle will commence. The water pressure in the filter cartridges 214, 216 will force the filter cartridges downwardly as indicated by the arrows on lid 218 in Fig 15c. Lips 299 will engage steps 297 and prevent the filter cartridges 214, 216 from being tilted accidentally whilst operational. The invention provides a simple and easy managed system to change filter cartridges. The difficulty involved in unscrewing the filter containers of the prior art are thus avoided.

The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and a certain specific embodiment by way of example.