WO2009010728A2

WO2009010728A2 - Improved water filter apparatus

Info

Publication number: WO2009010728A2
Application number: PCT/GB2008/002394
Authority: WO
Inventors: John Courtney
Original assignee: John Courtney
Priority date: 2007-07-13
Filing date: 2008-07-14
Publication date: 2009-01-22
Also published as: WO2009010728A3; GB2450913B; GB0713539D0; GB2450913A

Abstract

A water filter apparatus for filtering water, adapted to be coupled to piping of a piped water system, the water filter apparatus comprising a housing (20) having a first open end, a housing end cap (22) mountable over the first open end of the housing, the housing end cap having an aperture therethrough to, in use, be coupled to the piping of a piped water system, fastening means for fastening the housing end cap to the housing, and a filter element assembly which is removably insertable in the housing, the filter element assembly comprising a filter element (21) and a first end mount which, in use, channels water through the filter element, the filter element comprising a solid carbon block having a bore, the end mount having a protrusion, wherein the protrusion is removably receivable within the bore and securely attachable to the carbon block by f rictional engagement of the protrusion within the bore.

Description

Improved Water Filter Apparatus

Field of the Invention

The present invention relates to water filtration systems, and in particular it relates to water filter apparatus suitable for coupling to a piped water system, for example for providing filtered drinking water from mains tap water/piped water.

Background to the Invention

Water typically contains contaminants, which include particulate matter, chemicals and microorganisms. In drinking water, it is especially desirable to remove the harmful contaminants from the liquids before consuming them for maintenance of good health.

In view of these factors, it is highly important to provide a readily available source of substantially pure water free of harmful and distasteful contaminants to be consumed in working or domestic environments. For the consumer the filtration apparatus should be economical to install and run, compact, and ready to use with minimal intervention and need for maintenance. This is suitably achieved by providing a filtration apparatus that can be fitted to a mains tapwater system, suitably in the consumer's premises to filter out some or all of the impurities that the mains water suppliers did not remove, or which entered the water from the distribution pipework. These impurities may be small particles or may even be molecules that adversely affect the taste and odour of the water.

Several different methods are known for purification of water based on which many devices and apparatus have been designed. These methods and devices vary depending on the type of impurities present in water. Many filters use carbon as a filter media, primarily to reduce chlorine from the water from the mains water supply. Usually 'activated' carbon is used, ie. carbon which has been treated such that it has a slight positive charge. Early activated carbon filters used for home water treatment typically contained granular activated carbon (GAC) comprising a mixture of coarse carbon particles together with a binding material. Now, carbon filter media comprising finer, powdered carbon particles are available, known as powdered activated carbon block. The powdered activated carbon is extruded or moulded, together with a binding material, into a solid carbon block. Carbon block filter elements comprise smaller carbon particles and have a larger surface area to mass ratio than filter elements comprising granular activated carbon, and therefore carbon block filters are more effective at removing smaller sized contaminants. Filter elements are given a rating according to the size of particle which can be removed by the filter. GAC has a rating of around 20 microns, which means it removes anything of size 20 microns or larger from the water. Carbon block elements are now available having a rating of around 1-3 microns, which are more effective at removing chlorine from the water than previous filter elements.

During filtration, particles become trapped in the porous carbon media, therefore carbon filter elements have a limited lifespan and are required to be replaced frequently.

Domestic water filters for filtering water from the main supply, such as that described in US 2002/0100723, generally comprise a housing with a removable cap in which is mounted a replaceable filter cartridge. The filter cartridge comprises a cylindrical carbon filter element to which is attached a supportive end cap, fastened to one end of the element, to channel water through the filter element. The end cap is secured to the filter element by means of adhesive. Figure 1 shows a typical end cap 10 of the prior art, having inner 11 and outer annular walls 12, defining between them an annular channel or bath 13. When attaching the filter element to the end cap, the annular channel 13 is first filled with a liquid glue, the inner 11 and outer annular 12 walls effectively containing the glue within the channel 13. The end of the filter element is then placed in the annular channel 13, to glue it to the end cap.

When the filter element is required to be replaced, the filter cartridge is removed from the housing. The filter cartridge, consisting of the filter element and glued-on end cap, is not recyclable, and is therefore disposed of as waste. The filter cartridge is then replaced with a filter element with an end cap pre-glued on. It is a general objective of the present invention to provide an improved water filter system for filtering piped water which reduces non-recyclable waste arising from replacement of the filter cartridge.

Summary of the Invention

According to a first aspect of the present invention there is provided a water filter apparatus for filtering water, adapted to be coupled to piping of a piped water system, the water filter apparatus comprising a housing having a first open end, a housing end cap mountable over the first open end of the housing, the housing end cap having an aperture therethrough to, in use, be coupled to the piping of a piped water system, fastening means for fastening the housing end cap to the housing, and a filter element assembly which is removably insertable in the housing, the filter element assembly comprising a filter element and a first end mount which, in use, channels water through the filter element, the filter element comprising a solid carbon block having a bore, the end mount having a protrusion, wherein the protrusion is removably receivable within the bore and securely attachable to the carbon block by frictional engagement of the protrusion within the bore.

An advantage of the present invention is that when the filter assembly is required to be replaced, the filter element and end mount can easily be separated by pulling them apart, and a new filter element attached to the end mount by frictional engagement. Therefore the only part to be disposed of is the filter element, which is fully biodegradable. A new filter element can be installed by means of a simple friction fit with the end mount. The end mount is re-used with the new filter element, and therefore less waste is created when changing the filter element. When renewing the filter element, the only part to be replaced is the filter element itself (not the end mount) therefore the cost of renewing the filter element is lower than that for prior art filter assemblies. Suitably, the first end mount is removably securely attachable to the carbon block by frictional engagement of the protrusion within the bore, without glue or adhesive between the engaging surfaces of the first end mount and carbon block.

Preferably the filter element apparatus is configured such that fastening of the housing end cap to the housing causes the first end mount to fully engage with the filter element. Preferably the relative axial dimensions of the filter element, first end mount, housing, and housing end cap are such that on fastening of the housing end cap to the housing, the first end mount abuts an internal surface of the housing end cap and the filter element abuts an internal surface of the housing, whereby the first end mount is caused to fully engage with the filter element.

Preferably the first end mount has one or more projections that are adapted to be sandwiched between a face of the housing end cap and a face of the housing, to thereby mount and position the filter element in the housing, such that on fastening the housing end cap to the housing, the first end mount is caused to fully engage with the filter element. Particularly preferably the first end mount has an annular flange radiating therefrom adapted to be sandwiched between said face of the housing end cap and said faced of the housing.

Preferably the housing end cap is screw threadedly mountable to the housing. Particularly preferably the housing end cap is internally screw threaded to cooperatively engage with external screw threading on the housing.

Preferably the filter element is elongate and cylindrical in shape and has a blind bore, having a single opening or has a first opening at a first end of the filter element and a second opening at an opposite end of the filter element. Wherein the filter element has first and second openings, preferably the first end mount protrusion is removably receivable in the first opening of the bore, the water filter apparatus further comprising a second end mount having a protrusion which is removably receivable in the second opening of the bore, to direct water flowing axially through the filter element to flow radially through the filter element. The second end mount may be located within the housing, at an end remote from the first open end, and the second end mount and housing are formed as a unitary moulding.

Preferably the carbon block has a rating of three microns or less.

According to a further aspect of the invention there is provided a filter element assembly comprising a filter element and a first end mount, the filter element comprising a solid carbon block, the carbon block having a bore, the end mount comprising a protrusion, wherein the protrusion is removably receivable within the bore, whereby the protrusion is securable to the carbon block by frictional engagement of the protrusion within the bore.

According to a further aspect of the invention there is provided a replaceable filter element comprising a solid carbon block, the carbon block having a bore dimensioned to receive a protrusion of a filter element end mount, such that the protrusion can be removably secured in the bore by a friction fit.

According to a further aspect of the invention there is provided a method of filtering water using the water filter apparatus, filter element assembly, or replaceable filter element.

According to a further aspect of the invention there is provided a method of installing a replaceable filter element for a water filter apparatus, the method comprising the steps of attaching the end mount to the filter element by frictional engagement, placing the filter element and end mount in the housing and fastening the housing end cap to the housing.

Brief Description of the Drawings

A preferred embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein:

Figure 1 shows a perspective view of a prior art filter element end cap; Figures 2A and 2B are, respectively, longitudinal sectional views of a water filter apparatus along planes A-A and B-B of Figure 2C; Figure 2C is a plan view of the water filter apparatus; Figure 2D is an exploded, front elevational view of the water filter apparatus of Figures 2A-C, showing the housing end cap separated from the filter apparatus;

Figure 3 shows a longitudinal sectional view of the carbon block of Figure 2;

Figure 4 shows a longitudinal sectional view of an end mount of the water filter apparatus of Figures 2A-D;

Figure 5 shows a longitudinal sectional view of an alternative carbon block for use with the filter assembly;

Figure 6 shows a longitudinal sectional view of an alternative end mount;

Figure 7 shows a longitudinal sectional view of a further alternative end mount;

Figure 8 shows a longitudinal sectional view of a housing end cap for an in-line filter;

Figure 9 shows a longitudinal sectional view of the housing of an in-line filter.

Description of the Preferred Embodiments

Referring to figures 2A-2D, a preferred embodiment of the water filter apparatus comprises a substantially cylindrical, hollow body or housing 20 made of a thermoplastics material. The housing 20 has a broad opening at one end for insertion/removal of a filter element 21. A housing end cap 22 is screw threadedly mountable over the open end of the housing 20, having internal screw threads 23 which engage with corresponding external screw threads 24 on the housing 20, near to the housing opening. An O-ring seal 43 is provided between the end face of the housing 20 and an internal face of the housing end cap 22 to provide a watertight seal there between.

Within the housing is a solid cylindrical filter element 21. The filter element comprises a

5 solid carbon block of high grade carbon such as powdered activated carbon, preferably having a rating of 3 microns or less (ie. a carbon block having a 3 micron rating will filter out particles of diameter 3 microns or larger). Referring to figure 3, the carbon block 21 has a cylindrical bore 25, one end of which is open ended and the other end of which is closed ended 26. The carbon block 21 is typically formed by a moulding powdered

10 carbon.

Attachable to the filter element 22 is a spigot or end mount 30. Referring to figure 4, the end mount 30 comprises a circular plate portion 30a having a housing cap connector 31 extending from a top face of the plate portion 30a. The housing cap connector 31

15 couples, in use, with an inlet/outlet 41 of the housing end cap 22. Projecting from the centre of the bottom face of plate portion 30a is an elongate protrusion 32. Projecting from the outer perimeter of the bottom face of the plate portion 30a is an outer annular wall 33. The end mount 30 has a central bore 34 running throughout its length of the end mount 30, through the housing cap connector 31 and through the elongate

20. protrusion 32. Coupling of the housing cap connector 31 with the inlet/outlet 41 of the housing end cap 22 allows the end mount 30 to channel water into or out of the filter element bore 25. The end mount 30 also ensures that the filter element 21 is mounted centrally within the housing 20.

25 The protrusion 32 of the end mount 30 is configured to engage within the bore 25 of the carbon block 21 via a friction fit. The protrusion 32 has a circular cross-section, which is dimensioned such that it tightly fits within the circular bore 25 of the carbon block by frictional engagement. Referring to figures 2A and 2B, when the end mount 30 and carbon block 21 are attached, the outer annular wall 33 of the end mount 30 tightly 0 encircles the outer edge of the end of the carbon block 21. The carbon block 21 and end mount 30 are dimensioned to be securely attachable by frictional engagement, without the use of any glue or adhesive to attach the two. It is important that, when attached, carbon block 21 and end mount 30 are fully engaged, such that there are no substantial gaps between the engaging surfaces of the carbon block 21 and end mount 30. As stated previously, the carbon block is preferably made of a high grade carbon material. The higher the grade of carbon material used, the smaller the carbon particles are, giving a smoother outer surface to the carbon block. Use of a high grade carbon block having a smooth outer surface ensures that the corresponding surfaces of the carbon block and end mount fully engage, without the presence of gaps between the engaging surfaces that water could pass through, thereby bypassing the filter element. Preferably, when engaged, the gap between the engaging surfaces of the carbon block 21 and the end mount 30 will be 3 microns or less, such that any water which may happen to pass between the engaging surfaces will effectively be filtered of particles of size 3 microns or greater.

The apparatus is configured such that fastening of the end cap 22 onto the housing 20, not only forms a water tight seal between the housing and end cap, but also causes the end mount 30 to fully engage with the carbon block 21 , such that they are securely attached with substantially no gaps between end mount and carbon block, or a gap of 3 microns or less. The total length of the carbon block 21 and end mount 30, when fully engaged, matches the axial spacing between the internal base of the housing 20 and the internal surface of the housing end cap 22 to which the end mount 30 engages, when the housing and end cap are attached. In this way, once the carbon block 21 and end mount 30 have been placed inside the housing 20, fastening of the end cap 22 onto the housing 20 causes the end mount 30 to fully engage with the carbon block 21.

To install a new filter element, the user manually attaches the end mount 30 to a new carbon block 21 (inserting the protrusion 32 into the bore 25) and places the filter element in the housing 20. The user then fastens the housing end cap 22 onto the housing 20 by means of the screw threads 23, 24. This causes the end mount 30 to abut against an internal surface of the end cap 22 (in the embodiment of figure 2, the housing end connector 31 will engage with the housing end cap inlet/outlet 41) and also causes the bottom of the carbon block 21 to abut against the internal surface at the base of the housing 20, and effectively pushes the end mount 30 onto the carbon block 21 , such that the two form a strong frictional engagement with substantially no gaps there between. Preferably any gap between the end mount 30 and carbon block 21 will be 3 microns or less. The tolerances of the dimensions of the carbon block, end mount, housing and housing end cap are taken into account to ensure that despite small dimension variations resulting during manufacture, when assembled, the carbon block and end mount form a strong frictional engagement wherein any gap between the end mount and carbon block will be 3 microns or less.

The elongate protrusion 32 should be long enough such that a strong frictional engagement can be obtained between the carbon block 21 and the end mount 30. The longer the length of the elongate protrusion 32, the better the frictional fit between the end mount 30 and the carbon block 21 will be. Preferably the length of protrusion 32 of the end mount 30 roughly matches the wall thickness of the carbon block 21. This ensures a strong frictional engagement between the end mount 30 and the carbon block 21.

The assembled filter apparatus can be coupled to piping of a piped water system, via connectors 41 , 42 on the housing end cap. One connector 41 , 42 will be an inlet and the other an outlet. When assembled, connector 41 is in communication with the bore 25 of the carbon block 21. In use water may be directed into the filter apparatus via connector 41 , through the bore 34 of the end mount 30, and into the bore 25 of the carbon block 21, wherein the water passes radially through the carbon block and into the annular space between the carbon block and the housing (the water passes through both the sides of the carbon block and the closed bottom end of the block). Filtered water is then channelled out of the housing 20, out through connector 42. Alternatively connector 42 may act as an inlet and connector 41 as an outlet, such that during filtration water passes radially, from the outside of the carbon block 21 to the bore 25.

Referring to figure 5, an alternative embodiment of the carbon block is shown. The carbon block 21' may have a bore 25' with two opposing open ends (rather than an open end and a closed end, as shown in figure 3). The carbon block 21' of figure 5 is formed by extrusion. The double open ended carbon block 21' can be used exactly as the single open ended carbon block 21 of figure 3, except that the double open ended block 21 ' requires a second end mount to seal the second open end, so that in use, water is filtered through the sides of the carbon block and does not bypass the filter element. A second or bottom end mount (not shown in the figures) is provided, which is removably attachable to the second open end 26'. In common with the first or top end mount 30, the bottom end mount has a plate portion with an upstanding elongate portion which is receivable in the bottom open end 26' of the carbon block and fits tightly to form a strong frictional engagement with the carbon block. The bottom end mount may also have upstanding outer circumferential walls which encircle the outside of the carbon block 21 , when the bottom end mount is mounted to the block. As with the top end mount 30, it is important that carbon block 21' and bottom end mount are securely attached with substantially no gaps there between. As with the top end mount 30, preferably any gaps between engaging surfaces of the carbon block 21 and the bottom end mount are 3 microns or less when the carbon block 21 and bottom end mount are fully engaged.

When installing a double open ended carbon block 21', the bottom end mount and top end mount 30 can be mounted to the carbon block 21' by the user, then the filter element assembly is placed in the housing 20. As with the single open ended carbon block, the apparatus is configured such that fastening of the end cap 22 onto the housing 20 causes both the top end mount 30 and the bottom end mount to fully engage with the carbon block 21', such that there are substantially no gaps between the carbon block 21' and the top and bottom end mounts respectively. Preferably any gaps between engaging surfaces are 3 microns or less.

Instead of using a separate bottom end mount, the bottom end mount may be formed integrally with the housing. In this case the bottom end mount is located on the inside of the housing, at the base of the housing. When installing the double ended carbon block 21' into a housing having an integral bottom end mount, the top end mount 30 is attached to the carbon block 21', then the filter element assembly is placed in the housing. As before, the apparatus is configured such that fastening of the end cap onto the housing causes both the top end mount 30 and the bottom end mount to fully engage with the carbon block 21', such that they are securely frictionally engaged to the carbon block 21'. Referring to figure 6, an alternative embodiment of the top end mount 50 is shown. Similar to the end mount shown in figure 4, the end mount 50 comprises a circular plate portion 50a having a housing cap connector 51 extending from the top face of the plate portion 50a. Projecting from the centre of the bottom face of plate portion 50a is an elongate protrusion 52. Also projecting from the outer perimeter of the bottom face of the plate portion 50a is an outer annular wall 53. The end mount 50 has a central bore

54 running throughout the length of the end mount 50 for directing water into or out of the bore of the carbon block. As with the top end mount 30 of figure 3, the elongate protrusion 52 is dimensioned to be receivable within the carbon block bore and secureable by frictional engagement. The outer annular wall 53 of the end mount 50 tightly encircles the outer edge of the end of the carbon block when engaged.

Unlike the end mount shown in figure 4, the end mount of figure 6 has an annular flange

55 extending outwardly from the plate portion 50a. When the housing 20 and housing end cap 22 are threadedly coupled together, the annular flange 55 of the end mount 50 is sandwiched between an end face of housing 20 and an inner shoulder of the housing end cap 22. This firmly and stabley secures the end mount 50 in place to securely hold the carbon block extending longitudinally of the housing 20. Preferably there is an O- ring seal sandwiched between the annular flange 55 and the end face of housing 20. As with the end mount of figure 4, when using the end mount of figure 5, the filter apparatus is configured such that fastening of the end cap 22 onto the housing 20, not only forms a water tight seal to the apparatus, but also causes the end mount 50 to fully engage with the carbon block. The length of the carbon block matches the internal spacing between the bottom face of the end mount plate portion 50a to which the carbon block engages and an internal base surface or shoulder of the housing 20 against which the carbon block (or bottom end mount) abuts, when the filter apparatus is assembled. In this way, once the carbon block and end mount 50 have been placed inside the housing 20, fastening of the housing end cap 22 onto the housing 20 causes the end mount 50 to fully engage with the carbon block.

Referring to figure 7, a further alternative top end mount 60 is shown. Top end mount 60 is similar to that shown in figure 6 except that the top end mount 60 has an elongate tubular portion 61 projecting longitudinally from the top face of plate portion 60a of the end mount. The top end mount 60 is to be used with a housing end cap having an aperture, through which the top end of the tubular spigot 61 projects when assembled. The outermost end of the tubular spigot 61 is therefore externally exposed to be able to couple to water supply/delivery pipework.

In the filter assembly of figure 2, the water passes into and out of the assembly via the housing end cap 22, the housing 20 effectively acting as a sump. Alternatively the filter assembly may comprise an in-line configuration in which there is a single inlet/outlet in the housing end cap and a further inlet/outlet at the bottom of the housing. Figures 8 and 9 show respectively a housing end cap 72 and housing 70 for an in-line filter. The housing end cap 72 is screw threadedly mountable over an open end of the housing 70, having internal screw threads 75 which engage with corresponding external screw threads 76 on the housing 70, near to the housing opening.

When using an in-line apparatus, the water may be channelled into the apparatus via an inlet 71 in the housing end cap 72, via the bore of the end mount (not shown), into the carbon block bore (not shown), radially outwardly through the carbon block into the surrounding annular chamber of the housing, and then to the far end of the filter element to eventually pass out through an outlet 73 at the bottom of the housing 70. Alternatively the water may be directed in the opposite direction, such that the water passes radially from the outside surface of the carbon block to the inside.

The filter housing 70 shown in figure 9 can be used with either a single open ended carbon block or a double open ended carbon block (when using a double open ended carbon block, a bottom end mount is required to ensure that water does not bypass the carbon block).

When using the filter housing 70 of figure 9, preferably an end mount 60 as shown in figure 7 is used. There is an O-ring seal 74 sandwiched between an annular flange 65 of the end mount 60 and an end face of housing 70, to provide a watertight seal when the filter is assembled. As with the sump type housing of figure 2, when using an in-line housing, the apparatus is configured such that fastening of the end cap 72 onto the housing 70, not only forms a watertight seal to the apparatus, but also causes the end mount 60 to fully engage with the carbon block. As with the sump type housing, to install a new filter element, the user manually attaches the end mount 60 to a carbon block (inserting the protrusion 62 of the end mount into the bore of the carbon block) and inserts this in the housing. The length of the carbon block matches the internal spacing between the bottom face of the end mount plate portion 60a to which the carbon block engages and an internal base surface or shoulder of the housing 70 against which the carbon block (or bottom end mount) abuts, when the filter apparatus is assembled. As the housing end cap 72 is being fastened onto the housing 70, an internal surface of the housing end cap 72 abuts against the top of the end mount plate portion 60a. This forces the end mount 60 against the end face of housing 70, such that the O-ring seal 74 compresses, forming a watertight seal between the housing 70 and the end mount 60. This also forces the elongate protrusion 62 of the end mount 60 further into the bore of the carbon block, such that the end mount 60 and carbon block form a strong frictional engagement; once the housing end cap 72 is fastened onto the housing 70, preferably any gap between the end mount 60 and the carbon block is only 3 microns or less. In this way, once the carbon block and end mount 60 have been placed inside the housing 70, fastening of the housing end cap 72 onto the housing 70 causes the end mount 60 to fully engage with the carbon block.

An advantage of the present invention is that when an old filter cartridge is required to be replaced, the old filter element and end mount(s) can easily be pulled apart by the user, and a new filter element attached to the end mount(s) by frictional engagement. The only part to be disposed of is the old carbon block, which is fully biodegradable. The new filter element can be installed by means of a simple friction fit with the end mount(s). Fastening of the housing end cap onto the housing then ensures that the carbon block and end mount(s) are fully engaged.

Although described above with respect to specified embodiments, the present invention may be embodied in numerous different ways as embraced within the claims that follow.

Claims

1. A water filter apparatus for filtering water, adapted to be coupled to piping of a piped water system, the water filter apparatus comprising a housing having a first open end, a housing end cap mountable over the first open end of the housing, the housing end cap having an aperture therethrough to, in use, be coupled to the piping of a piped water system, fastening means for fastening the housing end cap to the housing, and a filter element assembly which is removably insertable in the housing, the filter element assembly comprising a filter element and a first end mount which, in use, channels water through the filter element, the filter element comprising a solid carbon block having a bore, the end mount having a protrusion, wherein the protrusion is removably receivable within the bore and securely attachable to the carbon block by frictional engagement of the protrusion within the bore.

2. A water filter apparatus according to claim 1 wherein the first end mount is removably securely attachable to the carbon block by frictional engagement of the protrusion within the bore, without glue or adhesive between the engaging surfaces of the first end mount and carbon block.

3. A water filter apparatus according to claim 1 or 2 wherein the filter element apparatus is configured such that fastening of the housing end cap to the housing causes the first end mount to fully engage with the filter element.

4. A water filter apparatus according to any preceding claim wherein the relative axial dimensions of the filter element, first end mount, housing, and housing end cap are such that on fastening of the housing end cap to the housing, the first end mount abuts an internal surface of the housing end cap and the filter element abuts an internal surface of the housing, whereby the first end mount is caused to fully engage with the filter element.

5. A water filter apparatus according to any preceding claim wherein the first end mount has one or more projections that are adapted to be sandwiched between a face of the housing end cap and a face of the housing, to thereby mount and position the filter element in the housing, such that on fastening the housing end cap to the housing, the first end mount is caused to fully engage with the filter element.

6. A water filter apparatus according to claim 5 wherein the first end mount has an annular flange radiating therefrom adapted to be sandwiched between said face of the housing end cap and said faced of the housing.

7. A water filter apparatus according to any preceding claim wherein the housing end cap is screw threadedly mountable to the housing.

8. A water filter apparatus according to any preceding claim wherein the housing end cap is internally screw threaded to cooperatively engage with external screw threading on the housing.

9. A water filter apparatus according to any preceding claim wherein the filter element is elongate and cylindrical in shape.

10. A water filter apparatus according to any preceding claim wherein the filter element bore is a blind bore, having a single opening.

11. A water filter apparatus according to any of claims 1 to 9 wherein the filter element bore has a first opening at a first end of the filter element and a second opening at an opposite end of the filter element.

12. A water filter apparatus according to claim 11 wherein the first end mount protrusion is removably receivable in the first opening of the bore, the water filter apparatus further comprising a second end mount having a protrusion which is removably receivable in the second opening of the bore, to direct water flowing axially through the filter element to flow radially through the filter element.

13. A water filter apparatus according to claim 12 wherein the second end mount is located within the housing, at an end remote from the first open end, and the second end mount and housing are formed as a unitary moulding.

14. A water filter apparatus according to any preceding claim wherein the carbon block has a rating of three microns or less.

15. A filter element assembly for a water filter apparatus according to any preceding claim, the filter element assembly comprising a filter element and a first end mount, the filter element comprising a solid carbon block, the carbon block having a bore, the end mount comprising a protrusion, wherein the protrusion is removably receivable within the bore, whereby the protrusion is securable to the carbon block by frictional engagement of the protrusion within the bore.

16. A replaceable filter element for a water filter apparatus according to any preceding claim, the filter element comprising a solid carbon block, the carbon block having a bore dimensioned to receive a protrusion of a filter element end mount, such that the protrusion can be removably secured in the bore by a friction fit.

17. A method of filtering water using a water filter apparatus, filter element assembly, or replaceable filter element according to any preceding claim.

18. A method of installing a replaceable filter element for a water filter apparatus as described in any preceding claim, the method comprising the steps of attaching the end mount to the filter element by frictional engagement, placing the filter element and end mount in the housing and fastening the housing end cap to the housing.

19. A water filter apparatus, a filter element assembly, a replaceable filter element, a method or filtering water, or a method of installing a replaceable filter element, substantially as hereinbefore described with reference to any suitable combination of the accompanying drawings.