Patent Application
20060144766
This application claims priority from United Kingdom Application Serial No. 0427825.5, filed 17 Dec. 2004, which is hereby incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to water treatment vessels, more particularly to domestic water treatment and storage vessels.
2. Background Information
Water treatment vessels are widely known in which a treatment cartridge is provided in order to reduce the presence of contaminants and improve the taste and odor of water for domestic use. The vessel may simply be a jug in which the treated water is stored and from which it may be poured. The vessel may alternatively be a water heating appliance such as a kettle or a water cooling device. An example of a cartridge which can be used in these different vessels is described in the Applicant's International Patent Application WO 2004/014519.
Wherever these cartridges are used there is a need for the user to replace them after their useful lifetime has expired. It is well known in the art, for example, to provide filter jugs with a usage indicator in which a ratchet mechanism indicates the number of times the jug has been filled. However, it is more desirable to have an indication of the time for which the cartridge has been in use because, for reasons of hygiene, the cartridge should be replaced after a certain period regardless of whether the treatment medium has been exhausted, and indeed filter jugs having an indicator of the time elapsed since the cartridge was last replaced are also known.
It has been proposed in WO 02/00552 to provide a filter cartridge with an integral indicator which shows the time elapsed since its activation. It is activated by the contact of water poured into the jug with a special dye which diffuses along a porous medium or with a reagent which reacts with a reaction medium.
The Applicant has appreciated however that the rate of diffusion is dependent upon the temperature, and therefore that such indicators if designed for cartridges or water treatment jugs for table-top use, will not be accurate if used for a refrigeration jug or a kettle. The behavior of indicators which use a chemical reaction to produce a progressive color change is also temperature dependent. It is an object of this invention to alleviate such problems.
According to a first aspect of the invention there is provided a water treatment vessel comprising: a water treatment cartridge; an elapsed time indicator; and denominating means, separate from the indicator, for denominating a portion of the indicator corresponding to a desired elapsed time so as to allow a user to see when the indicator indicates the desired elapsed time.
The invention also extends to the vessel per se, without the cartridge and/or indicator fitted. When viewed from a second aspect therefore the invention provides a water treatment vessel adapted for receiving in use an elapsed time indicator, said vessel comprising means for denominating a portion of the indicator corresponding to a desired elapsed time, so as to allow a user to see when the indicator indicates the desired elapsed time.
Thus in accordance with the invention, the actual elapsed time, which can conveniently correspond to the lifetime of the cartridge, can be given by co-operation between the indicator and the separate denominating means associated with the vessel that shows which part of the indicator to look at.
It will be appreciated by those skilled in the art that the separate denominating means may be designed so as to denominate a portion of the indicator means which is appropriate to the function of the vessel. In other words, the co-operation between the denominating means and the indicator depends on the temperature range to which the indicator is subjected in the vessel. This accounts for the fact that, at different indicator temperatures, a different portion of the same indicator will correspond to a particular desired elapsed time because the progress of the indicator is temperature dependent. The denominating means will therefore denominate different portions of the indicator for a water heating appliance, a water cooling appliance and a room temperature water treatment jug, for example.
In particular, where a water treatment cartridge is used in vessels which operate at different temperatures, the cooperation between the separate denominating means and the indicator can ensure that an accurate indication of the lifetime of the cartridge is given. There are clear economic benefits in being able to use a common cartridge and/or indicator in a wide variety of different vessels.
The indicator may be received anywhere in or on the vessel that is visible to a user. The indicator may be received inside the vessel, especially if the vessel has one or more transparent portions. In some preferred embodiments the indicator is on a water treatment cartridge received in the vessel. This is beneficial in being convenient for the user. A water treatment cartridge may have the elapsed time indicator, attached or integral, anywhere that is visible when it is installed in the vessel. For example the indicator may be on or in the side walls of the cartridge. In preferred embodiments the indicator is on the top of the cartridge so that it may be viewed from above.
In other preferred embodiments the indicator is received on a part of the vessel separate from the cartridge. This makes it easy for a user to install and replace the indicator. The indicator may be received in or on the side walls or lid of the vessel. Alternatively it could be received on a cordless power base for the vessel. In preferred embodiments though the vessel is arranged to receive an indicator in an external handle portion. The indicator is therefore easily viewed when the vessel is in use, without the need to open the vessel in order to view the cartridge and/or indicator. Furthermore, a user is more likely to notice and pay attention to the elapsed time indicated when the indicator is in a handle portion because the handle portion is always used.
The elapsed time indicator may be of any suitable type which is temperature dependent, but preferably the indicator is of the type in which a liquid advances along a medium either by diffusion or capillary action. Preferably the advancing liquid causes an observable color change either by diffusion of a colored liquid or by a chemical reaction. The migration of the color change through the medium gives a visible indication of the time elapsed. The chemical reaction may be chelation of a metal ion by a chelating agent, reaction of an acid/base with a pH indicator, reaction of an electron donor/acceptor with a redox indicator, or reaction between an enzyme and a substrate. The colored liquid may be an edible oil with a food dye so that water in contact with the indicator remains non-toxic even in the event that the indicator becomes damaged or splits open.
Most preferably the indicator is of the type is described in WO 03/007088. A water treatment cartridge having such an indicator is novel and inventive in its own right. When viewed from a further aspect, therefore, the invention provides a water treatment cartridge having an elapsed time indicator comprising a reservoir containing a colored indicator fluid and a migration medium, arranged such that said liquid is initially isolated from said migration medium, but on the application of pressure to the reservoir said liquid is brought into contact with the migration medium such that the liquid is caused to migrate along the migration medium, the extent of said migration giving an indication of elapsed time since activation.
Preferably a second reservoir is disposed between the first reservoir and the migration medium. Preferably the second reservoir comprises an inflatable pocket which is inflated by the liquid from the first reservoir. Further preferably the first reservoir is housed within the second reservoir. The first reservoir is preferably in a base layer of the indicator and the second reservoir is preferably in an intermediate layer located above the base layer.
In preferred embodiments the elapsed time indicator comprises a pressure-rupturable seal on the liquid reservoir, so that the indicator is activated by the simple application of pressure on the reservoir to release the liquid, e.g. into a second reservoir. The color change produced in the indicator by migration of the liquid through the migration medium may be any visible change, but preferably it is from any other color to red. This gives an indication of elapsed time that is easily understood by the user.
The rate of liquid migration or the rate of the reaction producing a color change, and therefore the indication of elapsed time, depends on the temperature of the indicator. However it has been appreciated by the Applicant that the same indicator, whether or not on a cartridge, may be advantageously used with one of a variety of water treatment vessels having denominating means as described above, because the denominating means can show which portion of the indicator corresponds to the desired elapsed time e.g., the lifetime of a cartridge, at the temperature at which the vessel operates.
The period of time taken for the color change to migrate through the whole migration medium depends on the temperature of the indicator. Indicators are available with time periods of between thirty minutes and six months at room temperature. In preferred embodiments, at the average temperature of about 40° C. experienced by an indicator installed in a kettle, the color change will not migrate through the whole of the migration medium until a time period of about four weeks has elapsed. At lower temperatures the color change will migrate through less of the migration medium within the same time period. For example if used in a fridge at an average temperature of 3-5° C. it may only migrate a quarter of the full distance.
The indicator may be of any suitable size and it may be of any shape such as a triangle, rectangle, polygon, circle or part of a circle. In some preferred embodiments the indicator is in the form of a disc, e.g., suitably sized to fit in the central portion on top of a cartridge. In such embodiments the migration medium itself could be annular. Alternatively it could be in the form of a spiral track or one or more radially extending strips. In other preferred embodiments the indicator is in the form of a strip, e.g., suitably sized to fit in the handle portion of a vessel.
In some embodiments the indicator exposes a continuous portion or the whole of the migration medium in which a color change is produced. In other embodiments the migration medium is covered with a transparent layer forming one or more windows through which the color change is visible. Such windows may be of any suitable shape but in preferred embodiments where the indicator is disc-shaped, the windows may be concentric arcuate sections.
The denominating means may denominate a portion of the indicator by covering, filtering, selecting, adapting or otherwise interacting with the indicator. For example it could comprise a scale, frame or marker which is applied to the indicator when the latter is received in the vessel. Preferably the denominating means comprises one or more windows so that only a selected portion of the indicator is visible. As previously described, the visible portion will be that which shows a color change after the desired time has elapsed, e.g., about one month for indicating the end of a water treatment cartridge life. This gives a particularly simple yes/no indication so that when a user is able to view a color change or other indication through the window, he or she knows that the predetermined time has elapsed and it is therefore time to change the cartridge. A functionally equivalent alternative would have a lens or other viewer focused on only the particular region of the indicator.
The denominating means may be integral with the vessel or it may be mounted on the vessel. In some preferred embodiments in which the indicator is provided on the cartridge the denominating means is preferably situated in the vessel such that a water treatment cartridge may be mounted directly beneath it. If the cartridge has an indicator on top then this arrangement allows a user to selectively view a denominated portion of the indicator from above. The vessel may have a viewing means in its walls which allow a user to view the denominating means. Preferably, however, the vessel has a lid with a viewing means, such as a window, which allows a user to view the denominating means through the lid. A user can therefore view the denominating means, and the denominated portion of the indicator when a cartridge is mounted in the vessel, through the walls or lid of the appliance even when it is in use.
In other preferred embodiments in which the indicator is separate from the cartridge, the denominating means is preferably integral with a handle portion of the vessel. This arrangement allows an indicator to be received in the handle portion such that it can be viewed through the denominating means and is easily visible from the outside of the vessel by a user as previously explained. Preferably the handle portion of the vessel comprises one or more windows for denominating and selecting a portion of the indicator for viewing.
The indicator could be activated manually before being installed in the vessel. Preferably, however, the vessel is arranged to activate the indicator when it is installed, either by itself or as part of a cartridge. Where the indicator is on a cartridge this may be achieved by a cooperation between the vessel and the cartridge which produces pressure on a pressure-rupturable seal of the indicator. For example, either the cartridge or some part of the vessel may be provided with means for activating the indicator such as a protrusion, node, rib, ramp or other surface feature which is pressed against the pressure-rupturable seal of the indicator only when the cartridge is installed in the vessel.
Where the indicator is separate, the means for receiving it is preferably provided with means for activating the indicator such as a protrusion, node, rib, ramp or other surface feature which is pressed against the pressure-rupturable seal of the indicator only when the indicator is installed.
Both arrangements ensure that the indicator is activated straightaway upon installation without the need for a user to remember to activate it. The activating means may be separate to the denominating means, but preferably it is integral with the denominating means.
Where provided the means for receiving an indicator preferably comprises a keying arrangement which is so shaped that an indicator may only be inserted in a particular orientation. The indicator may be asymmetrical or have some other keying feature that cooperates with the keying arrangement of the vessel. In some preferred embodiments the vessel has a channel for receiving an indicator, the channel and the indicator being so shaped that the indicator can only be fully inserted into the channel in a particular orientation. This ensures that the indication of elapsed time migrates in the correct direction along the indicator relative to the denominating means of the vessel, so that the correct elapsed time is indicated.
These and other features and advantages of the present invention will become apparent in light of the drawings and detailed description of the present invention provided below.
With reference to
An elapsed time indicator disc 12 is recessed in the central surface 14 of the cartridge cap 16. As shown in
The indicator 12 may be of a type having a pressure-rupturable seal on the liquid reservoir. The indicator 12 may be activated by breaking this seal as will be explained below. After activation a color change progresses as a visible front expanding from the centre towards the periphery of the disc 12. In the embodiment shown in
As can be seen from
The denominating mask 20 shown in
The denominating mask 30 shown in
The denominating mask 40 shown in
Thus it will be appreciated that the same type of cartridge having a time indicator can be mounted in any kind of water treatment vessel and still accurately indicate a desired elapsed time (typically four weeks for replacement of a standard water treatment cartridge) regardless of the temperatures to which the indicator is exposed in the vessel. This is because each vessel has a denominating mask, such as those described with reference to
The indicator 12 may be activated by a cooperation between the cartridge 2 and denominating mask 20 as best seen from
Referring now to
The handle portion 100 has an aperture 108 at the opposite end to the channel opening 104 which allows a user to see when an indicator strip 112 has been pushed fully into the channel 106. The aperture 108 is large enough that a user can apply finger pressure to the end of the indicator strip 112 to aid its removal when it needs to be replaced. A new indicator strip can then be slid into the channel and is immediately activated as described above.
An alternative embodiment is shown in
The channel 201 is provided with a triggering feature 206 in the form of a pointer. As can be more clearly seen in
The handle portion 400 shown in
The handle portion 500 shown in
In various of the embodiments described above, the cartridge 2 has a disc-shaped indicator 12 attached to the central surface 14 of the cartridge cap 16. However it will be appreciated that the indicator is not limited to being a disc and may be of any shape as required or suitable for a particular cartridge. For example the indicator could be a strip. Conversely, the handle portion in various of the other embodiments described is not limited to having a longitudinal channel for receiving an indicator strip, but could have any kind of aperture, channel, recess or other means for accepting an indicator of any shape. For example the indicator could be disc-shaped and the handle portion could have a semi-circular slot for receiving the indicator.
The denominating means of the vessel is not limited to a window and could alternatively provide a scale or other markings which allow a user to see when the desired elapsed time is indicated. For example an indicator could simply be fitted into a recess on a handle or other portion of the vessel alongside which a time-scale is marked and against which the progress of dye in the indicator can be compared and measured. It will be appreciated that the denominating mask for use with a water treatment cartridge having an indicator in accordance with the invention is not limited to the circular form shown with arcuate windows and could, for example, comprise a single circular or rectangular window, or a series of windows spaced along an indicator strip.
It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the present invention and that the invention is not to be considered limited to what is described and exemplified in the specification.
| Number | Date | Country | Kind |
|---|---|---|---|
| GB 0427825.5 | Dec 2004 | GB | national |
