GB2294631A - A kettle for filtering water and subsequent boiling of the filtered water - Google Patents

Abstract

A filter kettle comprises a cold water reservoir (2) surrounding a hot water chamber (3) that is provided with an electrical heating element (16); a filter element (8); and pump means (9) for pumping on demand cold water from the cold water reservoir (2) through the filter (8) into the hot water chamber (3). The pumping of the water from the cold water reservoir to the hot water chamber prior to heating that water provides a rapid and effective means for filling the hot water chamber with filtered water prior to heating. The particular design of kettle, with the cold water reservoir surrounding the hot water chamber, has the advantage that the kettle does not become excessively hot to the touch even when it contains boiling water. <IMAGE>

Description

~ITL Filter Kettle Field of the Invention This invention relates to electric kettles for boiling filtered water for domestic consumption.

Background Art Water filters are known, in which water from a domestic supply is filtered prior to consumption. In general, those filters allow the water to percolate through the filter medium by gravity, although some domestic water filters are known which pass the water through the filter under pressure, for example by pumping it. GB 2250281 and GB 2257429 are examples of domestic water filters incorporating pumps.

If a user wishes to make a hot drink using filtered water, then it is necessary to transfer the filtered water from the receptacle associated with the filter to a kettle, and then use the kettle to heat the water.

Prior to the present invention, there had never been a proposal for a dual function filter kettle, in which water was first filtered and then heated to boiling. On appreciating the desirability of such a filter kettle, immediate design problems became apparent including the need to have a reservoir for cold water and a separate heating chamber, the need to control the pumping transfer of the water from the reservoir to the hot water chamber and the fact that many filter media lose their efficiency when heated.

The Invention The invention provides a filter kettle comprising a cold water reservoir surrounding a hot water chamber that is provided with an electrical heating element; means for filling the cold water reservoir with cold water; a filter element; and pump means for pumping on demand cold water from the cold water reservoir through the filter into the hot water chamber.

The basic design of the filter kettle according to the invention has a number of advantages, many not immediately apparent. For example, the provision of a cold water reservoir surrounding the hot water chamber means that when the kettle element is being used to heat the water in the hot water chamber, the outside of the kettle is maintained cool to the touch. This is true whether the cold water reservoir is filled, partially filled or empty, since even an empty reservoir provides thermal insulation between the hot water chamber and the outside of the vessel. One advantageous feature than can optionally be incorporated into the design is to create a double wall between the cold water reservoir and the hot water chamber, for additional insulation of the outside of the vessel.If desired, the space defined by that double wall may be air-filled or filled with a suitable insulating material.

The means for filling the cold water reservoir may be a special fill opening provided in a lid of the filter kettle, leading directly to the cold water reservoir.

That may be an opening provided with its own sealable closure means, or it may be permanently open to the atmosphere if provided diametrically opposite a pouring spout for the kettle. Alternatively the fill opening may be actually through the pouring spout of the kettle, in which case the user is provided with the means to control a baffle or closure, to cause the filling cold water to pass into the cold water reservoir rather than into the hot water chamber. Conversely, when pouring hot water from the filter kettle, the baffle or closure is moved to an alternative position in which it permits discharge of the water from the hot water chamber but not from the cold water reservoir.

The filter medium is preferably provided beneath the cold water reservoir and hot water chamber. Because many filter media are adversely affected by heat, it is preferable for the filter element to be annular or partannular, enabling it to be located substantially beneath the cold water reservoir so as to avoid excessive heat transfer problems from the hot water chamber. Moreover, a layer of thermally insulating material is preferably provided between the hot water chamber and the filter medium, and preferably extends continuously beneath the entire base of the hot water chamber.

The pump means is preferably actuable by means of a push button on a handle of the filter kettle, and designed to be operative for as long as that push button is depressed. Pumps are available which are not damaged by dry running, and it is advantageous that the user will be able to hear a change in the sound of the pump as it transfers the last of the water from the cold water reservoir through the filter to the hot water chamber. If an annular filter element is provided as discussed above, then the pump preferably is situated at the centre of the filter element, beneath the hot water chamber.

Advantageously it draws the cold water from the bottom of the cold water reservoir, passing it through the filter and then to the top of the hot water chamber.

Preferably the filter kettle of the invention is provided with two visual filling indicators, comprising sight or observation chambers on the outside of the kettle, one indicating the level of water in the cold water reservoir and the other indicating the level of water in the hot water chamber. In use, the user takes an empty filter kettle to the cold water supply, fills it until the level indicator for the cold water reservoir indicates that sufficient water has been loaded for immediate use, and then depresses the push button to operate the pump until it is seen that a sufficient quantity of water has been pumped into the hot water chamber. During this pumping the level in the cold water reservoir will decrease and that in the hot water chamber will increase, both as seen through the relevant sight glasses.The kettle can then be switched on to heat the water in the hot water chamber.

If the user forgets to operate the push button to cause the cold water to be pumped from the cold water reservoir through the filter to the hot water chamber, but still switches on the heating element, then a conventional overheating cut-out will operate, to prevent damage to the kettle. If the water is allowed to boil in the hot water chamber, then a conventional steam sensor will operate to cause the heating element to cut out.

The jug kettle of the invention is particularly well suited to a so-called cordless design, whereby the kettle vessel is used in conjunction with a stand connected to mains electricity, so that simply by placing the kettle on the stand its element is plugged into the electrical mains. The particular advantage of such a cordless design in connection with the filter kettle of the invention is that both the heating element and the pump can be powered from the same mains supply, although it may be desirable for the kettle stand to provide a lower voltage output to the pump than to the heating element.

Drawings Figure 1 is a side elevation of a filter kettle according to the invention; Figure 2 is a plan view from above; Figure 3 is a plan view from below; and Figures 4, 5 and 6 are vertical sections along the lines IV-IV, V-V and VI-VI of Figure 2.

All the drawings are schematic only.

Description of the Drawings The kettle of the invention comprises a main vessel body moulding 1 in which are defined an annular cold water reservoir 2 surrounding a central hot water chamber 3.

The separation between the cold reservoir 2 and the hot water chamber 3 is provided by a double wall 4a,4b of the main vessel body moulding, between the walls 4a and 4b being defined a generally annular space 5 which provides thermal insulation between the cold water reservoir 2 and the hot water chamber 3. Although not illustrated in the drawings, this space 5 may if desired be filled with thermally insulating material to increase the thermal insulation between the two chambers.

A service area 6 is provided beneath the cold water reservoir 2 and the hot water chamber 3, by virtue of a depending annular outer skirt 7. That service chamber 6, which as illustrated is open to the bottom of the vessel, houses a filter element 8 and a pump 9. The pump 9 is operated through a push button 10 of a carrying handle 11 of the filter kettle (Figure 1).

The pump 9 can be connected either to push water through the filter element 8 or to draw water through the filter element 8, and for illustative purposes only the latter configuration is illustrated in Figure 6. Water passes from the bottom of the cold water reservoir 2 into the filter element 8 by means of a push-lock hydraulic connection; and is then drawn from the other end of the filter element 8 through the pump to pass upwardly through a transfer conduit 12 moulded within the space 5 defined between the double walls 4a and 4b, for discharge into the top of the hot water chamber 3 through a lid 13.

Also moulded into the space 5 between the double walls 4a and 4b is a steam passage 14 which supplies steam from the space above the hot water in the hot water chamber 3 to the vicinity of a temperature sensor element 15 associated with an electrical heating element 16.

Filling the kettle is through a fill hole 70 in the lid 13, which as illustrated is at the handle side of the kettle. This means that the fill hole could be left permanently open, or it could be covered in use by means of a slidable cap 18 associated with the lid 13, as shown in Figure 2. One advantage of the use of a slidable cap such as 18 is that it can be made to incorporate a part of the transfer conduit 12, so that rotation of the cap through 1800 permits the filtered cold water to be discharged not into the hot water chamber 3 but externally of the filter kettle to, for example, a separate cup or vessel (enabling the filter kettle to be used as a conventional water filter as well as its primary intended use as a filter kettle).

A layer of thermally insulating material 19 is shown between the filter element 8 and the bottom of the hot water chamber 3, and this layer 19 preferably extends across the whole of the base of the hot water chamber and cold water reservoirs 2 and 3 as shown in Figures 4 to 6.

The shape and design of the filter element are of particular relevance. The filter element 8 can be readily removed for replacement through the open base of the service chamber 6. The hydraulic connections between the filter element 8 and the cold water reservoir 2 on the one hand and the pump 9 on the other hand are by means of push-lock hydraulic connections which simply push together to provide a firm and secure hydraulic connection but cannot be disconnected until a retaining collar is physically moved by hand. Such connections are well-known in themselves and are not specifically illustrated in the drawings.The filter element is generally C-shaped in plan view, with the hydraulic connections at opposite ends so that water pumped through the filter medium in the filter element 8 has to pass completely around the arcuate length of the filter element, thus achieving maximum efficiency. The shell of the filter element is made from two pieces of plastic, one being generally concave of approximately semicircular section and the other being a flat top. In this way the filter element can be moulded, filled with filter material and then sealed by application of the top, all automatically by modern manufacturing and filling machinery. Figure 1 shows sight glasses 20 and 21 which serve a visual indication, without having to remove the lid 13, of the amount of water in the hot water chamber 3 and the cold water reservoir 2 respectively.In use, the user fills the water from the fill hole 17 until it is judged that a sufficient quantity of water has been charged into the cold water reservoir 2, and then returns the kettle to a conventional stand (not shown) connected to electricity mains supply. That provides the power connection to both the electrical element 16 and the pump 9, and depression of the push button 10 in the handle 11 is sufficient to cause the water to be pumped from the cold water reservoir 2 through the filter element 8 into the hot water chamber 3. Either this pumping may be continued until the cold water reservoir 2 is dry (as indicated both by the sight glass 21 and by a change in the sound of the pump motor) or the user may decide to transfer only sufficient cold water for immediate needs, leaving the cold water reservoir partially filled. The kettle is then switched on, and the water in the hot water chamber 3 brought to the boil.

Many variants of the above design ar possible. For example, the cold water filling may be through the pouring spout of the kettle, in which case a baffle element would have to be provided to enable the user to control the flow of water into the cold water reservoir 2 as opposed to the hot water chamber 3. The filter element 8 may be made with transparent or translucent walls, so that when filled with a suitable colourindicating filter material, a colour change will indicate to the user when it is time to change that filter element.

Filter materials that may be used in the filter element include granular activated carbon, ion exchange resins and mixtures thereof in addition to a wide variety of alternative and conventional filter materials.

Claims (10)

1. A filter kettle comprising a cold water reservoir surrounding a hot water chamber that is provided with an electrical heating element; means for filling the cold water reservoir with cold water; a filter element; and pump means for pumping on demand cold water from the cold water reservoir through the filter element into the hot water chamber.

2. A filter kettle according to claim 1, wherein the cold water reservoir is thermally insulated from the hot water chamber.

3. A filter kettle according to claim 2, wherein the thermal insulation between the cold water reservoir and hot water chamber is provided by a double wall which is air-filled or filled with a thermally insulating material.

4. A filter kettle according to any preceding claim, wherein the means for filling the cold water reservoir with cold water comprises a fill opening provided in a lid of the kettle, diametrically opposite a pouring spout for the kettle.

5. A filter kettle according to any of claims 1 to 3, wherein the means for filling the cold water reservoir with cold water comprises a fill opening provided in a lid of the kettle, provided with a sealable closure means.

6. A filter kettle according to any of claims 1 to 3, wherein the means for filling the cold water reservoir with cold water comprises a baffle or closure to cause cold water filled into a pouring spout for the kettle to pass into the cold water reservoir rather than into the hot water chamber.

7. A filter kettle according to any preceding claim, wherein the filter medium is annular or part-annular, and located substantially beneath the cold water reservoir.

8. A filter kettle according to any preceding claim, wherein the pump means is actuable by means of a push button on a handle of the filter kettle, and is operative for as long as the push button is depressed.

9. A filter kettle according to any preceding claim, further comprising two visual filling indicators, one indicating the level of water in the cold water reservoir and the other indicating the level of water in the hot water chamber.

10. A filter kettle substantially as described herein with reference to the drawings.