GB2325179A

GB2325179A - Potable water filtration device incorporating a pump

Info

Publication number: GB2325179A
Application number: GB9810255A
Authority: GB
Inventors: Steve Ulery; Philip Randolph Hartley; Kevin Christian Coullahan; Matthew Allison Herron; Steve Andrepont; Scott Duplantis; Lawrence Eugene Davis; Matthew John Barthelemy
Original assignee: Sunbeam Products Inc
Current assignee: Sunbeam Products Inc
Priority date: 1997-05-16
Filing date: 1998-05-13
Publication date: 1998-11-18
Also published as: WO1998051628A1; CA2237536A1; BR9801189A; AU7366798A; KR19980087057A; GB9810255D0; JPH10337565A

Abstract

An apparatus for the filtration of already potable water for domestic or office use comprises container 40 for unfiltered water and housing 10 containing pump 50, filter cartridge 70 and filtered water outlet 14. Container 40 sits upon base 30 which is integrally formed with housing 10. Unfiltered water flows via valves (46) and 34 and base 30 into pump 50 which forces the water through filter cartridge 70 for purification and out via water outlet 14 to a suitable collection vessel, e.g. a glass. The pump is activated and water is dispensed when switch 12 is pressed, for example, by holding a glass against it or ON switch 18 is depressed. Filter cartridge 70 has a fixed life and is replaced when used. It can be easily removed via recess 72. Its condition is monitored so that a warning light 20 will begin to flash as cartridge 70 nears the end of its useful life. This light remains continuously lit when the filter has reached the end of its life and must be replaced. The pump 50 will not operate if the filter cartridge 70 is absent or if the container 40 is empty or has been removed for cleaning or filling etc. Alternative indication/warning means are also described such as use of more than one light or the use of audible sounds.

Description

WATER FILTRATION DEVICE AND RELATED FILTER CARTRIDGE This invention relates to filters for water and, specifically, to filters for domestic or office use which are used to further purify already potable water to remove undesirable chemicals, odors, minerals and biological agents such as cysts and bacterial static.

The use of filters for the supplemental filtering of already potable water to remove chlorine, odors, unwanted minerals (such as lead) and bacteria are commonly known and in widespread use. Such filters come in a plethora of types, including, for example, units which connect to the end of a faucet or showerhead, units which allow water to flow by gravity into a pitcher or other container, units which attach directly to the end of a bottle, and various types of countertop units, most of which require some sort of attachment to a faucet via a hose. In addition, units exist which connect directly to a domestic water main, thereby providing whole-house water filtration.

Generally, such filtration devices fall into two broad categories. The first category includes filtration devices in which the unfiltered water is pulled through the filtration element of the device by the force of gravity.

The second category includes filtration devices that require that the water be forced through the filtration element of the device by pressure supplied either from the local municipal water company, or by a pump, usually located within the filtration device.

The effectiveness of such devices in removing impurities from water bears a direct relationship to the ability of the filtration element to filter particles of varying sizes. Generally, the smaller the particle that a filtration element is capable of filtering, the more difficult it is for water to permeate the filtration medium which is being used, since the filtration medium, usually activated carbon, must be packed together more tightly.

Thus, filters capable of filtering very small particles, for example, those less than 2 microns, may take a very long time to filter a quantity of water using gravity flow, or may require that the water be forced through the filtration- medium under pressure. On the other hand, filters capable of filtering only larger particles may be able to filter water by allowing gravity to pull the water through the filtration medium.

Filters wherein water is pulled through the filtration element by the force of gravity are well known. Two such filters are shown in Mudra, et al. (U.S. Pat. No.

5,536,396) and Byrne (U.S. Pat. No. 4,528,095). Both filters disclose using loose activated charcoal as the filtration medium, with a piece of filter paper to hold the charcoal. Such filters would be capable of filtering particles in the 10 plus micron range, and should be able to remove, for example, chlorine taste and smell from water. However, such filters would be incapable of removing smaller particles, such as bacterial cysts like giardia and cryptosporidium, which are much smaller, usually in the 3-4 micron range.

Filters which use tap water pressure to force the water through the filtration element are shown in Clack (U.S. Pat. No. 5,454,944), Whittier (U.S. Pat. No.

5,078,864) and Gales, et al. (U.S. Pat. No. 4,744,895).

These filters would be capable of filtering out much smaller particles than the gravity flow filters discussed above, and, in the case of a reverse osmosis filter, as shown in Whittier, are capable of filtering out particles down to about .01 microns in size, wllicll would include bacteria which cause, for example, cholera, diptheria and ecoli.

One problem with such filters, however, is their dependency on tap water pressure to force the water through the filtration element. This can present a problem in, for example, rural areas with sporadic water pressure or in foreign countries where reliable municipal water systems may be nonexistent.

These problems can be solved by using a filter having a manual or an electric pump to force the water through the filtration element, as shown in Heimelstein (U.S. Pat. No. 5,0;9,402) and Hembree, et al. (U.S. No.

5,268,093). With a filter having a pump to force water through the filtration element, one need not be dependent on pressure from the tap. Furthermore, the use of a pump avoids the need to have a connection between the water faucet and the filtration unit, which could be unsightly and inconvenient.

One disadvantage of filtration devices having an electric pump, such as that shown in Heimelstein, is that water is filtered on a batch basis instead of on an as-needed basis. This allows filtered water to sit prior to use, providing an opportunity for the filtered water to become recontaminated through contact with ambient air.

According to one aspect of the present invention, there is provided an apparatus for filtering liquid, the apparatus colnpflsing: a) a housing having an exterior surface; b) an unfiltered liquid reservoir having a base and a side wall extending upwardly fiom said base to define an opening; c) a platform, defined by said housing, for receiving said unfiltered liquid reservoir; d) a replaceable filter cartridge, having a filtration element disposed therein; e) a filtered liquid outlet defined by said housing; and f) a pump for pumping unfiltered liquid fi-om said unfiltered liquid reservoir, through said filter cartridge and out through said filtered liquid outlet.

Another aspect of the invention provides an apparatus for filtering potable water, the apparatus comprising: a) a housing; b) an unfiltered water reservoir having a base and a side wall extending upwardly from said base to define an opening; c) a platform, defined by said housing, having a top with a depression defined therein for receiving said unfiltered water reservoir; d) a first valve located on said base of said unfiltered water reservoir which opens when said unfiltered water reservoir is placed on said platform and closes when said unfiltered water reservoir is removed from said platform; e) an opening defined in said top of said platfoim covered by a second valve which opens when said unfiltered water reservoir is placed on said platfonn and closes wllen said unfiltered water reservoir is removed from said platform; f) a replaceable filter cartridge having a limited useful life, said filter cartridge removably mounted in a recess defined by said housing; g) a filtered water outlet defined by said housing; h) a switch; i) a mechanical pump driven by an electrical motor wherein said motor operates when said switch is pressed and ceases to operate when said switch is released, wherein said pump draws water from said opening in said platform, pumps said water through said filter cartridge and out said unfiltered water outlet and further wherein said motor will not operate if said filter cartridge is absent or if said unfiltered water reservoir is empty or if said filter cartridge has exceeded said useful life; j) a light which blinks when said filter cartridge nears the end of said ~ useful life and which solidly lights when said filter cartridge exceeds said useful life; and k) pair of pushbutton type switches wherein pressing one pushbutton of said pair causes said motor to operate and wherein pressing said other pushbutton of said pair causes said motor to cease operating.

A still fulther aspect of the invention provides a system for filtering liquid comprising: a) A receptacle for holding unfiltered liquid, said receptacle including an upper opening for receiving unfiltered liquid therein; b) a filter; c) a pump adapted to receive liquid from said receptacle and pump said liquid through said filter; d) a filter holder for holding said filter, said filter holder including a dispensing polt through which filtered liquid may be dispensed; and e) a switch on said filter holder, said switch adapted to initiate a pumping cycle whereby when a container for receiving filtered liquid is placed beneath said dispensing point, said switch activates said pump, thereby pumping liquid fi-om said receptacle through said filter and out of said dispensing polt for collection in said container.

According to a fultllel- aspect of the present invention, there is provided a filter cartridge comprising: a) a housing; b) a filtration element disposed within said housing; c) a first orifice defined by said housing; d) a second orifice defined by said housing; e) a first tubular fitting connected to said first orifice; and f) a second tubular fitting connected to said second orifice, wherein water centering said first orifice must pass through said filtration element before exiting said second orifice.

The prefened embodiment of the present invention discloses a water filter having an electric pump, a removable unfiltered water reservoir and the capability to provide filtered water on an as-needed basis.

The housing of the container preferably provides a platform on which the unfiltered water reservoir sits. When removed from the platform for filing, a spring loaded valve in the base of the unfiltered water reservoir prevents water from escaping. When the unfiltered water reservoir is in place on the platform, the valve opens to allow water to exit the unfiltered water reservoir into the base of the platform.

An electric motor and pump combination draws water from the base of the platform and forces it through a filter cartridge and out a filtered water outlet in the housing. An elongated contact switch is positioned on the outside of- the housing below the water outlet, such that a glass or pitcher placed under the outlet and held against the switch will cause the motor and pump to operate. In the preferred embodiment, a switch is also provided to manually turn on the motor and pump when filling, for example, a bowl, which would be to short to contact the switch when placed on the countertop under the outlet.

The preferred embodiment contains a plastic filter cartridge containing a carbon block type filtration element. The cartridge is removable and needs to be replaced after filtering approximately 250 gallons of water. The device contains a counter which keeps track of the time that the motor and pump are operating. Since the flow rate of the pump is known, is can be calculated how much time the pump must operate to pump 250 gallons of water. When the pump has pumped approximately 190 gallons of water, the user is given a warning that the filter cartridge will soon need to be replaced. After filtering 250 gallons, the unit will not operate until the filter cartridge is replaced. In the preferred embodiment, the warning given after 190 gallons of water have been filtered takes the form of a blinking light located on the exterior of the housing. The blinking light stays solidly lit after 250 gallons have been filtered.

The preferred embodiment of the invention is equipped with safeties and interlocks which prevent the unit from operating if the unfiltered water reservoir is empty and when the filter cartridge is absent from the unit. These interlocks prevent water from spilling from the unit and also guard against having the motor burn out.

In order that the present invention may be more readily understood and so that fuithei features thereof may be appreciated, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a front elevational view of the device.

Figure 2 shows a right elevational view of the device.

Figure 3 shows a rear elevational view of the device.

Figure 4 shows a right perspective view of the device.

Figure 5 shows a left elevational view of the device.

Figure 6 shows a front elevational view of the device with the pitcher removed.

Figure 7 shows a right perspective view of the device with the pitcher removed.

Figure 8 shows an enlarged detail of the bottom of the pitcher of the device.

Figure 9 shows a cross sectional view of the pitcher and the base of the device through Section 9-9 of Figure 3.

Figure 10 shows an enlarged cross sectional detail of the valve assemblies of the pitcher and the base of the device through Section 9-9 of Figure 3.

Figure II shows a real elevational view of the device with the filter cartridge removed.

Figure 12 shows a perspective cross sectional view of the main housing of the device through Section 12-12 of Figure 11.

Figure 13 a shows a front elevational view of the filter cartridge.

Figure 13b shows a right elevational view of the filter cartridge.

Figure 13c shows a cross sectional view of the filter cartridge through Section 13-13 of Figure 13a.

Figure 13d shows a top plan view of the filter cartridge.

Figure 14a shows a left rear perspective view of the filter cartridge.

Figure 14b shows a front right perspective view of the filter cartridge.

Figure 15 shows a sample circuit which implements the functions of the device.

Figure 16 shows a logic flow diagram of the circuit of Figure 15.

As best shown in Figures 1-4, the device as a whole consists of two upright structures, housing 10 and pitcher 40. Housing 10 contains filter cartridge 70 motor 49, pump 50 and printed circuit board 53. Defined on the exterior of housing 10, near the top thereof, is a nacelle, 24, which includes filtered water outlet 14 on the underside thereof and user controls 16, 18, 20 and 22 on the top thereof. Housing 10 includes switch 12, used to start motor 49. Pitcher 40 sits atop base 30, which is integral with housing 10.

Pitcher 40, best shown in Figures 1-4, is used to store unfiltered water prior to filtration and dispensing by the filtration apparatus of the device. Pitcher 40 is removable from base 30 for filling and cleaning. Handle 42 aids the user in handling pitcher 40 and lid 44 can be removed when filling pitcher 40 with water.

Unfiltered water is dispensed from pitcher 40 via valve 46, located on the underside thereof, as best shown in enlarged detail in Figure 8 and in cross section in Figures 9 and 10, through mating valve 34, located on the top of base 30, as best shown in Figure 7 and in cross section in Figures 9 and 10. Referring to Figure 10, when pitcher 46 is not in place on base 30, stud 48 is urged downwardly by spring 47, pulling seal 48 against wall of pitcher 40j thus closing valve 46 and sealing pitcher 40, preventing water from leaking therefrom. Additionally, plunger 36 is urged upwardly by spring 35, thereby holding plunger 36 against seal 37 in the wall of base 30, thereby closing valve 34. This prevents any unfiltered water still in the unit from backing up and overflowing into depression 32 through valve 34.

When pitcher 40 is in place on base 30, valve 46 communicates with valve 34 to allow water from pitcher 40 to flow into base 30. Plunger 36 and stud 48 push against each other to open both valve 46 and valve 34. The path of the water, 39, as it flows from pitcher 40 into base 30 is shown in Figure 10.

Valve 34 is plumbed to the upstream end of pump 50, which pumps water from pitcher 40 through filter cartridge 70 and out filtered water outlet 14, located on the underside of nacelle 24. Depressing switch 12, usually via pressure applied by a glass or pitcher held thereagainst, causes motor 49, shown in Figure 12 to start, thereby driving pump 50, also shown in Figure 12. Although in the preferred embodiment a contact switch is used to start motor 49, it should be obvious that any type of device could be used, for example, a device which detects the presence of a container held under filtered water outlet 14 without physical contact between the container and the device, such as are commonly used in public restrooms to start and stop faucets and flush toilets without contact between the user and the fixture.

Filter cartridge 70 is shown in Figures 3 and 5 and in detail in Figures 13a-d and 14a-b, and is located in recess 72 in the rear of housing 10. Filter cartridge 70 is accessible from the outside of housing 10, to allow it to be easily replaced by the user after it has reached the end of its use-ful life.

In the preferred embodiment, housing 68 of filter cartridge 70 is substantially prism-shaped, having a cross section in the shape of a flat projection of a spherical triangle, that is, the cross section of housing 68 is substantially triangular in shape but with convex or arcuate sides. Recess 72 is shaped to accept filter cartridge 70.

Filter cartridge 70 is meant to be inserted into recess 72 corner first, such that inlet 78 and outlet 76 engage fittings 58 and 60 respectively, as shown in Figure 11. Thus, filter cartridge 70 has outlet 76 protruding from the leading edge corner of housing 68 and inlet 78 protruding from the middle of one side of housing 68, such that inlet 78 and outlet 68 are parallel to each other and in the same vertical plane as each other. This is best shown in Figures 13a-d. The configuration of filter cartridge 70, as described above, allows it to be inserted into recess 72 only one way, in order to make it impossible for a user to insert cartridge 70 incorrectly.

Figure 11 shows the rear of housing 10 with filter cartridge 70 removed from recess 72. Fitting 58 in recess 72 is plumbed to the downstream end of pump 50 and connects to water inlet 78 in filter cartridge 70. Fitting 60 is plumbed to filtered water outlet 14 and connects to water outlet 76 in filter cartridge 70.

Filtration element 82 is disposed within filter cartridge 70 and may consist of any type of filtration element well known to those of ordinary skill in the art.

In the preferred embodiment, an extruded carbon block filter is employed, such as is available from KX Industries of Orange, Connecticut as the "Matrix Pbl" filter. This type of filtration element is capable of filtering particles in the 3-4 micron range. In an alternative embodiment, filtration element 82 may be wrapped with a membrane consisting of a first layer of a non-woven prefiltration material and a second layer of a hydrophilic microporous material to enhance its filtration capabilities, thereby allowing it to filter smaller particles, down to approximately .1 micron. Such a filtration element is available from KX Industries of Orange, Connecticut as the "Gen3" filter.

As shown in cross section in Figure 13c, filtration element 82 has a generally tubular shape with axial bore 88 extending therethrough. One end of filtration element 82 is capped by end cap 86, thus sealing that end of axial bore 88. The other end of axial bore 88 is plumbed directly to outlet 76. Outlet 76 is connected to fitting 60 located in recess 72. Thus, water enters the filter cartridge from pump 50 via fitting 58 through inlet 78 and passes into cavity 69. Cavity 69 is defined by housing 68 of the filter cartridge, which in the preferred embodiment is composed of opaque plastic, and the outer wall of filtration element 82. To exit cavity 69, water must permeate through the wall of filtration element 82 into axial bore 88, and exit axial bore 88 through outlet 76.

The connections between fitting 58 and filter cartridge inlet 78, and fitting 60 and filtered cartridge outlet 76 are sealed by O-rings 90, composed of an elastomeric material, such as rubber, shown in Figures 13ad. Tab i4, located on the top end of filter cartridge housing 68, rigidly holds filter cartridge 70 within recess 72 by engaging catch 92, shown in Figure 12, located in recess 72, thus compressing O-rings 90 to form a watertight seal; In addition, housing 68 is water-tight except for inlet 78 and outlet 76.

Depression 80 and ridges 79, located on the top end of filter cartridge housing 68, and best shown in Figures 13d and 14a-b, aid the user in installing and removing filter cartridge 70 from recess 72. The user installs filter cartridge 70 within recess 72 by first engaging notch 75, defined on the bottom of filter cartridge housing 68, shown in Figure 13c, with protrusion 93 (not shown) defined in recess 72. Tab 74, is then engaged with catch 92, thereby making the connections between fittings 58 and 60 and inlet and outlet 78 and 76 respectively. The user removes filter cartridge 70 from recess 72 by placing a finger in depression 80 and pulling outwardly, aided by ridges 79, thereby disengaging tab 74 from catch 92, and lifting filter cartridge 70, thus disengaging protrusion 92 from notch 75.

Located on top of nacelle 24 are ON switch 18 and OFF switch 16. These switches are used to turn motor 49 on and off when it is inconvenient to start motor 49 via switch 12, as, for example, when filling a bowl sitting on the countertop which is too short to contact switch 12. Also located on top of nacelle 24 is warning light 20. Warning light 20 begins to flash when filter cartridge 70 has neared the end of its useful life, which occurs after approximately 190 gallons of water have been filtered.

When the filter cartridge has reached the end of its useful life, after filtering approximately 250 gallons of water, warning light 20 will remain solidly lit. Although a single light is used for both warning and shut off of the unit after the filter's useful life has been expended, it should be obvious that two lights could be used, as could an audio warning instead of a visual warning.

Figure 15 shows a sample of a circuit 52, located on printed circuit board 53 in housing 10, which provides safety features which prevent motor 49 from operating if filter cartridge 70 is absent from recess 72 or if pitcher 40 is empty or absent from base 30. Circuit 52 detects when filter cartridge 70 is absent by an interlock switch located in recess 72, which is closed when filter cartridge 70 is in place within recess 72. Circuit 52 detects when pitcher 40 is empty by detecting a decrease in the electrical current drawn by motor 49. Using this same method, circuit 52 can also detect when pitcher 40 is absent.

Circuit 52 also provides the function of disabling motor 49 after the useful life of filter cartridge 70 is expended. This is done by counting the hours that motor 49 and pump 50 have been operating and thereby calculating the amount of water which has passed through filter cartridge 70. After the user has replaced filter cartridge 70, reset button 22, located on top of nacelle 24, may be pressed to reset the filtered water gallon counter to zero, thereby re-enabling motor 49, and to turn off warning light 20.

Alternatively, reset button 22 could be eliminated by detecting when filter cartridge 70 has been replaced by, for example, noting the temporary absence of filter cartridge 70, and then automatically resetting the filtered water gallon counter to zero, turning off warning light 20 and re-enabling motor 49.

Figure 16 shows a logic flow diagram of the functions provided by circuit 52, shown in Figure 15. It is obvious that the specific circuit shown as the preferred embodiment in Figure 15 is only one implementation of a circuit capable of providing the features described above, and that any circuit which implements the above-described features could readily be substituted for the circuit shown in Figure 15. It is also obvious that the above-described features could be implemented by a circuit which does not conform to the flow logic diagram of Figure 16.

Although the most common use for this product is the filtering of already potable water, it should be obvious that any it could be used to filter any liquid, and thus the invention should not be construed as being limited only to the filtration of water.

It should also be apparent to those of ordinary skill in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not limited by the specific embodiments illustrated and described but only by the scope of the appended claims, including all equivalents thereof.

Claims

CLAIMS:

1. An apparatus for filtering liquid, the apparatus comprising: a) a housing having an exterior surface; b) an unfiltered liquid reservoir having a base and a side wall extending upwardly from said base to define an opening; c) a platform, defined by said housing, for receiving said unfiltered liquid reservoir; d) a replaceable filter cartridge, having a filtration element disposed therein; e) a filtered liquid outlet defined by said housing; and f) a pump for pumping unfiltered liquid from said unfiltered liquid reservoir, through said filter cartridge and out through said filtered liquid outlet.

2. The apparatus of claim 1 wherein said pump comprises an electric motor driving a mechanical pump.

3. The apparatus of claim 2, further comprising a device for turning said motor on and off.

4. The apparatus of claim 3, wherein said device for turning said motor on and off comprises a push type switch wherein said motor is turned on when said switch is pressed and turned off when said switch is released.

5. The apparatus of claim 4 wherein said switch is located below said filtered liquid outlet such that a container held under said filtered liquid outlet for receiving filtered liquid may contact said switch to turn said motor on.

6. The apparatus of claim 3 wherein said device for turning said motor on and off comprises a pair of pushbutton type switches wherein pushing one switch of the pair will turn the motor on and pushing the other switch of the pair will turn the motor off.

7. The apparatus of any preceding claim, wherein said platform defines a depression therein to receive said unfiltered liquid reservoir.

8. The apparatus of any preceding claim, wherein said unfiltered liquid reservoir has a first valve disposed in said base thereof and wherein said first valve is open when said reservoir is placed on said platform and wherein said first valve is closed when said reservoir is removed from said platform.

9. The apparatus of claim 8 wherein said platform defines an opening therein which is covered by a second valve and wherein said second valve is open when said reservoir is placed on said platform and wherein said second valve is closed when said reservoir is removed from said platform.

10. The apparatus of claim 9 wherein said first valve is in communication with said second valve to allow liquid to flow from said reservoir through said first and second valves to said opening in said platform.

11. The apparatus of claim 9 or claim 10, wherein said pump draws water from said opening in said platform.

12. The apparatus of any preceding claim, wherein said housing further comprises a means for retaining said filter cartridge, and wherein said housing further defines an opening through which said filter cartridge can be inserted into and removed from said housing.

13. The apparatus of any one of claims 1 to 11, wherein said housing defines a recess for receiving said filter cartridge.

14. The apparatus of claim 13, further comprising a mechanism for releaseably locking said filter cartridge into place within said recess.

15. The apparatus of claim 14, wherein said mechanism comprises a tab defined on said filter cartridge which engages a catch defined within said cavity.

16. The apparatus of claim 15, wherein said mechanism further comprises a notch defined on said filter cartridge which engages a protrusion defmed within said recess.

17. The apparatus of any one of claims 13 to 16, wherein said filter cartridge is in the shape of a triangular prism having three arcuate sides and two ends and wherein said recess is shaped to receive said filter cartridge.

18. The apparatus of any preceding claim, wherein said filter cartridge is composed of plastic.

19. The apparatus of any preceding claim, wherein said filter cartridge is opaque.

20. The apparatus of any preceding claim, wherein said filter cartridge further comprises a water inlet fitting and a water outlet fitting.

21. The apparatus of claim 20, wherein said housing defines an unfiltered water opening which mates with said water inlet fitting of said filter cartridge and a filtered water opening which mates with said water outlet fitting of said filter cartridge.

22. The apparatus of claim 21, wherein said unfiltered water opening is connected to said pump and wherein said filtered water opening is connected to said filtered water outlet.

23. The apparatus of any preceding claim, wherein said filtration element is a carbon block type filter.

24. The apparatus of any preceding claim, wherein said filtration element will filter particles having a diameter greater than or equal to 1 micron.

25. The apparatus of any one of claims 1 to 23, wherein said filtration element is wrapped with a microporous membrane.

26. The apparatus of claim 25, wherein said filtration element will filter particles having a diameter greater than or equal to .1 microns.

27. The apparatus of any preceding claims, further comprising means for detecting when said filter cartridge is absent.

28. The apparatus of claim 27, wherein said means for detecting when said filter cartridge is absent comprises an interlock switch.

29. The apparatus of claim 27 or claim 28, wherein said pumping means will not operate if said filter cartridge is absent.

30. The apparatus of any preceding claim, further comprising means for detecting when said unfiltered water reservoir is empty.

31. The apparatus of claim 30, wherein said pumping means will not operate if said unfiltered water reservoir is empty

32. The apparatus of claim 30 or 31, both as dependent upon any one of claims 2 to 29, wherein said means for detecting when said unfiltered water reservoir is empty comprises an apparatus which detects a decrease in the electrical current consumed by said motor.

33. The apparatus of any preceding claim, further comprising means for detecting when said unfiltered reservoir is absent.

34. The apparatus of claim 33, wherein said pumping means will not operate if said unfiltered water reservoir is absent.

35. The apparatus of claim 33 or claim 34, both as dependent upon any one of claims 2 to 32 wherein said means for detecting when said unfiltered reservoir is absent comprises an apparatus which detects a decrease in the electrical current consumed by said motor.

36. The apparatus of any preceding claim, wherein said filter cartridge has a limited useful life and further comprising means for determining when said filter cartridge has reached the end of said useful life.

37. The apparatus of claim 36 further comprising: a) means for providing a warning that said filter cartridge is nearing the end of its useful life; and b) means for providing an indication that said filter has reached the end of its useful life.

38. The apparatus of claim 36 or claim 37, wherein said means for determining when said filter cartridge has reached the end of said useful life comprises a counter which counts the number of hours that said pumping means has run.

39. The apparatus of claim 38, wherein said pump has a specific flow rate and wherein said counter further calculates how much water has passed through said filter cartridge by multiplying said number of hours by said flow rate, and compares said calculation to said useful life of said filter cartridge.

40. The apparatus of claim 38 or claim 39, further comprising a reset button which resets said counter to zero when pressed.

41. The apparatus of claim 40, wherein said pumping means will not operate after said filter cartridge has reached the end of said useful life until said reset button has been pressed.

42. The apparatus of any ones of claims 38 to 41, wherein said counter is reset to zero when said filter cartridge is replaced.

43. The apparatus of any one of claims 37 to 42, further comprising a light mounted on said exterior surface of said housing and wherein said means for warning comprises said light blinking on and off and wherein said means for indicating comprises said light remaining solidly lit.

44. The apparatus of one of claims 37 to 42, further comprising a pair of lights mounted on said exterior surface of said housing and wherein said means for warning comprises solidly lighting one light of said pair and wherein said means for indicating comprises solidly lighting said other light of said pair.

45. The apparatus of claim 43 or claim 44, further comprising a reset button that turns said means for warning and means for indicating off.

46. The apparatus of any one of claims 43 to 45, wherein said means for warning and said means for indicating are turned off when said filter cartridge is replaced.

47. The apparatus of any one of claims 37 to 46, further comprising an audible alarm and wherein said means for warning and means for indicating comprise sounding said audible alarm.

48. The apparatus of any one of claims 36 to 47, wherein said pumping means will not operate after said filter cartridge has reached the end of said useful life until said filter cartridge has been replaced.

49. The apparatus of any preceding claim, wherein said filter cartridge nears the end of its useful life after filtering approximately 190 gallons of water.

50. The apparatus of any one of claims 1 to 48, wherein said filter cartridge reaches the end of its useful life after filtering approximately 250 gallons of water.

51. An apparatus for filtering potable water, the apparatus comprising: a) a housing; b) an unfiltered water reservoir having a base and a side wall extending upwardly from said base to define an opening; c) a platform, defined by said housing, having a top with a depression defined therein for receiving said unfiltered water reservoir; d) a first valve located on said base of said unfiltered water reservoir which opens when said unfiltered water reservoir is placed on said platform and closes when said unfiltered water reservoir is removed from said platform; e) an opening defined in said top of said platform covered by a second valve which opens when said unfiltered water reservoir is placed on said platform and closes when said unfiltered water reservoir is removed from said platform; f) a replaceable filter cartridge having a limited useful life, said filter cartridge removeably mounted in a recess defined by said housing; g) a filtered water outlet defined by said housing; h) a switch; i) a mechanical pump driven by an electrical motor wherein said motor operates when said switch is pressed and ceases to operate when said switch is released, wherein said pump draws water from said opening in said platform, pumps said water through said filter cartridge and out said unfiltered water outlet and further wherein said motor will not operate if said filter cartridge is absent or if said unfiltered water reservoir is empty or if said filter cartridge has exceeded said useful life; j) a light which blinks when said filter cartridge nears the end of said useful life and which solidly lights when said filter cartridge exceeds said useful life; and k) pair of pushbutton type switches wherein pressing one pushbutton of said pair causes said motor to operate and wherein pressing said other pushbutton of said pair causes said motor to cease operating.

52. A system for filtering liquid comprising: a) A receptacle for holding unfiltered liquid, said receptacle including an upper opening for receiving unfiltered liquid therein; b) a filter; c) a pump adapted to receive liquid from said receptacle and pump said liquid through said filter; d) a filter holder for holding said filter, said filter holder including a dispensing port through which filtered liquid may be dispensed; and e) a switch on said filter holder, said switch adapted to initiate a pumping cycle whereby when a container for receiving filtered liquid is placed beneath said dispensing port, said switch activates said pump, thereby pumping liquid from said receptacle through said filter and out of said dispensing port for collection in said container.

53. The system of claim 52, further comprising: a) a lower opening defined in said receptacle for dispensing unfiltered liquid therefrom, said lower opening including a valve adapted to close, thereby retaining liquid in said receptacle during a filling operation and to open, thereby dispensing liquid therefrom during a dispensing operation; and b) a platform on which said receptacle is received, said platform including a connection port for communicating with said valve and opening said valve when said receptacle is placed on said platform, said connection port being in communication with said pump.

54. The system of claim 53, wherein said connection port opens when said receptacle is placed on said platform and closes when said receptacle is removed from said platform.

55. The system of claim 52, claim 53 or claim 54, wherein said filter comprises: a) a housing which is removable from said filter holder; and b) a filtration element disposed within said housing.

56. A filter cartridge comprising: a) a housing; b) a filtration element disposed within said housing; c) a first orifice defined by said housing; d) a second orifice defined by said housing; e) a first tubular fitting connected to said first orifice; and f) a second tubular fitting connected to said second orifice, wherein water entering said first orifice must pass through said filtration element before exiting said second orifice.

57. The filter cartridge of claim 56, wherein said first tubular fitting has a proximal end, a distal end, and a first outside diameter and wherein said distal end is connected to said first orifice and wherein said proximal end defines a shoulder and a flange, said flange having a second outside diameter smaller than said first outside diameter, and wherein said second tubular fitting has a proximal end, a distal end, and a first outside diameter and wherein said distal end is connected to said second orifice and wherein said proximal end defines a shoulder and a flange, said flange having a second outside diameter smaller than said first outside diameter, further comprising: a) a first 0-ring, disposed around said flange of said first tubular fitting adjacent said shoulder; and b) a second 0-ring, disposed around said flange of said second tubular fitting adjacent said shoulder.

58. The filter cartridge of claim 57, wherein said first and second 0-rings are composed of rubber.

59. The filter cartridge of any one of claims 56 to 58, wherein said second tubular fitting extends from said housing from said second orifice along a line that is a radial line of a circle inscribed within a cross section of said housing.

60. The filter cartridge of claim 59, wherein said first tubular fitting extends from said housing from said first orifice such that said first tubular fitting and said second tubular fitting are parallel and lie in a plane defined by a right cross section of the housing.

61. The filter cartridge of any one of claims 56 to 60, wherein said housing is substantially prism shaped, having three sides defining three corners therebetween, and two ends.

62. The filter cartridge of claim 61, further comprising a tab defined on said housing and protruding therefrom.

63. The filter cartridge of claim 62, wherein said tab protrudes from one of said ends of said housing.

64. The filter cartridge of claim 63, further comprising a notch defined in said other end of said housing.

65. The filter cartridge of claim 61, further comprising a depression defined in one of said ends of said housing.

66. The filter cartridge of claim 65, further comprising a plurality of ridges defined within said depression.

67. The filter cartridge of any one of claims 61 to 66, wherein said ends have a substantially triangular shape.

68. The filter cartridge of any one of claims 61 to 66, wherein said sides are convex and wherein said ends are shaped as a flat projection of a spherical triangle.

69. The filter cartridge of any one of claims 61 to 68, wherein said second tubular fitting extends from said housing from said second orifice at one of said corners between two of said sides.

70. The filter cartridge of claim 69, wherein said first tubular fitting extends from said housing from said first orifice on one of said sides adjacent to said corner from which said second tubular fitting extends.

71. The filter cartridge of any one of claims 56 to 70, wherein said filtration element is an extruded carbon block.

72. The filter cartridge of any one of claims 56 to 71, wherein said filtration element will remove particles having a diameter greater than or equal to 3 microns from a liquid.

73. The filter cartridge of any one of claims 56 to 71, wherein said filtration element is wrapped with a microporous membrane.

74. The filter cartridge of claim 73, wherein said filtration element will remove particles having a diameter greater than or equal to .1 microns from a liquid.

75. The filter cartridge of any one of claims 56 to 74,wherein said filtration element is cylindrical in shape, having an outer wall, two ends and an axial bore which extends through said ends.

76. The filter cartridge of claim 75, further comprising a cap which closes said axial bore at one of said ends of said filtration element.

77. The filter cartridge of claim 76 wherein said second orifice is plumbed to said axial bore on said end of said filtration element opposite said cap.

78. The filter cartridge of claim 75 wherein said first orifice communicates with a space defined by said housing and said outer wall of said filtration element.

79. The filter cartridge of any one of claims 56 to 78, wherein said housing is watertight except for said unfiltered water inlet orifice and said filtered water outlet orifice.

80. The filter cartridge of any one of claims 56 to 79, wherein unfiltered water enters said housing at said first orifice and must pass through said outer wall of said filtration element and through said axial bore of said filtration element to exit said housing via said second orifice.

81. The filter cartridge of any one of claims 56 to 80, wherein said filtration element has a limited useful lifespan measured in number of gallons filtered.

82. The filter cartridge of claim 81 where said filtration element reaches said limited useful life after filtering approximately 250 gallons of water.

83. The filter cartridge of any one of claims 56 to 82, wherein said housing is composed of plastic.

84. The filter cartridge of claim 83, wherein said plastic is opaque.

85. An apparatus for filtering liquid substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

86. A filter cartridge substantially as hereinbefore described with reference to and as shown in Figures 13 and 14 of the accompanying representations.

87. Any novel feature or combination of features disclosed herein.