GB2321179A - Adjustable drip-feed head for a coffee maker - Google Patents

Abstract

A drip-feed head for a beverage-making appliance such as a coffee maker is described in which the flavour of the beverage is user-adjustable. Heated water for the beverage is arranged to fall upon a slotted plate (10) which overlies, and can rotate relative to, a fixed plate (15). The fixed plate is apertured, being formed either with slots (16, 17, 18) or with arrays of individual holes and the arrangement is such that respective ones of the slots (12,13,14) in the rotatable plate overly the apertures in the fixed plate at different radii depending on the relative rotational positions of the two plates. By this means, the water can be caused to eat the lower, fixed plate at said different radii and thus to impact upon different regions of a brewing station disposed beneath the lower plate.

Description

DOMESTIC APPLIANCE FOR MAKING HOT BEVERAGES This invention relates to domestic appliances for making hot beverages such as coffee.

Domestic coffee-making appliances typically comprise a tank which is charged with fresh water, a flow heater connected to the tank and a riser tube which conveys hot water from the flow heater up to a distributor (or so called drip-feed) head which is positioned above a coffee-filter receiving station.

Hot water falls from the head into ground coffee retained in the filter and, after running down through the ground coffee and through the filter, into a carafe.

Typically the carafe is supported on a base which is heated, often by same heating element as used by the flow heater referred to previously, and a valve is disposed under the receiving station to prevent hot water dripping on to the (heated) base unless the carafe is placed thereon.

Appliances of this kind work well and have gained wide acceptance One drawback, however, is that they provide the user with little or no control over the strength of the coffee. This drawback has been recognised and addressed in recent years, but current solutions have disadvantages in that they are either crude, being based upon dilution of the coffee in the carafe by diversion of some of the heated water direct to the carafe rather than to the drip-feed head and through the ground coffee, or rather expensive to manufacture bearing in mind the price levels that have been established for such appliances.

This invention aims to overcome at least in part the above-mentioned.

drawback and/or disadvantages, providing a domestic appliance for making hot beverages in which the strength of the beverage is readily adjustable, by the user, by means of an efficient mechanism which is cost-effective to produce.

The invention also encompasses a beverage-making appliance incorporating such a drip-feed head.

In order that the invention may be clearly understood and readily carried into effect, one embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 shows, in general view, a typical coffee maker and some of its principal component parts.

Figure 2 shows, in detailed perspective view, the components of a drip-feed head, in accordance with one example of the invention, for use in a coffee maker.

Referring now to Figure 1, the coffee maker shown comprises a heated base 1 on which stands a carafe or jug 2 positioned to receive the brewed coffee which is kept warm by the heat applied to base 1. As mentioned previously, the heating of the base 1 can advantageously be effected by the electrical heater device used to heat the water which is used to brew the coffee. The heater device (not shown in Figure 1) is located proximate to the underside of base 1, within a suitable housing section and a switch 3 is provided by means of which power can be applied to the heater device.

Above the location of the carafe is a housing portion 4 which is internally shaped into conical or similar form and is adapted to receive a filter device, usually a mesh of plastics material, into which first a paper coffee filter and then ground coffee is placed. The housing portion 4 swings outwardly to enable the filter and coffee to be added prior to brewing and taken out afterwards.

Behind the housing portion 4 is located a water tank which holds sufficient water to fill the carafe. The tank is accessed through a raisable lid 5 and is usually charged with water by means of the carafe itself.

A water feed tube (not shown) runs from the bottom of the water tank and is connected as the inlet to a water tube that forms the passage of the heating arrangement. The outlet of the water tube is connected, via a riser tube, to a dripfeed head disposed above the housing portion 4 and positioned so that heated water drips on to the coffee contained therein. The hot water permeates through the coffee and then, having brewed, falls into the carafe via a valve which is opened only when the carafe is properly placed on the base 1.

Figure 2 shows a configuration of drip-feed head in accordance with an example of the invention. A riser tube, shown at 6, conveys hot water from the.

region of the base of the coffee-maker (see Figure 1) up to the area of the head, generally shown at 7.

As will be seen, the head 7 comprises a plurality of substantially flat plate like components which are coaxially juxtaposed with one another.

Water flowing up the riser tube 6 is conveyed through a conduit 8 radially across an upper plate member 9, which is fixed, and showers down on to a middle plate member 10 which is rotatable, by means of a control knob 11, relative to the plate member 9. Member 10 is dished and is formed with a plurality (three in this example) of linear, radial slots 12, 13 and 14. These slots allow water to fall through on to a lower plate member 15 which, like plate member 9, is fixed. Plate member 15 is formed with a plurality (in this example three) of arcuate slots 16, 17 and 18 which are configured and positioned to interact with the linear, radial slots 12, 13 and 14 in the rotatable plate member 10 in a manner now to be described.

The arrangement is such that, when the plate member 10 is in one extreme rotational position, the slots 12, 13 and 14 overly only those parts of slots 16, 17 and 18 respectively which are adjacent the rotational axis 19 of the assembly. As the plate member 10 is rotated progressively further away from this extreme position, the slots 12, 13 and 14 respectively overly parts of the slots 16, 17 and 18 which are progressively further from the rotational axis 19 until the opposite extreme position is reached. In this position, the slots 12, 13 and 14 respectively overly those parts of slots 16, 17 and 18 which are farthest from the rotational axis 19.

It will be recalled that the ground coffee is held, in a container which generally conforms to an up-turned cone, beneath the drip-feed head 7, with the rotational axis 19 passing through or adjacent the apex of the cone. In these circumstances, it can be seen that the hot water that falls through the drip-feed head 7 onto the ground coffee can be caused to vary significantly with regard to the radial position at which it impacts the coffee. The position can be varied from an innermost position close to the rotational axis 19 to an outer position near the edge of the up-turned conical container. This variation in position, as is known, permits significant variation in the strength of the brewed coffee.

The combination of linear slots 12, 13 and 14 in plate member 10 and arcuate, or somewhat serpentine, slots 16, 17 and 18 in plate member 15 (as shown in Figure 2) has been found to work well in practice, and the combination of the shapes of the respective overlying slots in the two plate members has been chosen such as to present a desired overall slot configuration through which the water can exit at different radial distances from the rotational axis 19. It will be appreciated.

however that other configurations and shapes of slots and differing numbers of slots can be used if desired to achieve a particular programme of slot openings. In particular, of course, the arcuate slots 16, 17 and 18 could be formed, if desired, in the middle (rotational) plate member 10 and the linear slots 12, 13 and 14 in the lower (fixed) plate member 15.

Depending upon the effect desired, rotational movement of the plate member 10 can be made smooth and continuous between end stops, or it could be made stepwise, so that a finite number of strength settings can be used. In either event, at least the slots 16, 17 and 18 in the fixed lower plate member 15 may not be continuous but comprise a series of discrete apertures disposed along a desired path.

It may be preferred to retain continuous slots in the rotatable member 10 in order to reduce the risk of the water flow being obstructed by surface tension effects.

In any event, various known expedients may be adopted if desired, or if necessary, to promote the flow of water through the overlying slots. In particular, the slot edges can be bevelled and/or serrated and/or the various plate members can be dished at selected angles if it is found necessary with any particular design of drip-feed head. In practice, the pressure of water issuing from the conduit 8 is quite high and is usually sufficient to promote the desired flow of water without significant attention to such expedients.

A drip feed head in accordance with the invention is economically and conveniently produced from moulded plastics components and is extremely shallow in the dimension measured along the rotational axis 19. It lends itself to incorporation in several basic designs of coffee maker, thus allowing economies of scale in production too, and moreover it is effective and reliable in operation.

Claims (12)

1 A drip-feed head for a beverage-making appliance, the head comprising a first plate-like member formed with a plurality of slots and disposed to receive, on one of its major surfaces, heated liquid for said beverage, a second plate-like member coaxially juxtaposed with the first member and formed with apertures cooperative with said slots, and means for relatively rotating said first and second members about their common axis so as to align respective of said slots with respective of said apertures at different radial position across said plates.

2 A drip-feed head according to claim 1 wherein the facing surfaces of the first and second plate-like members are smooth.

3 A drip-feed head according to either of claims 1 and 2 wherein a plurality of substantially linear radial slots is formed in one of said first and second plate-like members and a similar plurality of non-linear slots is formed in the other of said plate-like members.

4 A drip-feed head according to claim 3 wherein the edges of the slots formed in said second plate-like member are bevelled to promote the flow of water therethrough.

5 A drip-feed head according to either of claims 3 and 4 wherein the edges of.

the slots formed in said second plate-like member are serrated in order to promote the flow of water therethrough.

6 A drip-feed head according to any of claims 3 to 5 wherein each of said nonlinear slots is arcuate.

7 A drip-feed head according to any preceding claim including a third plate-like member disposed to overly said first plate-like member and forming part of a distribution system for heated water, the first and third plate-like members being rotationally fixed and sandwiching between them the second plate-like member, and user-operable means for rotating the second plate-like member relative to the other plate-like members.

8 A drip-feed head according to claim 7 wherein said user-operable means comprises a knob co-operating with a protuberance carried by said second plate-like member and protruding through said third plate-like member.

9 A drip-feed head according to any preceding claim including means for causing the relative rotation between said first and second plate-like members to proceed in steps.

10 A drip-feed head according to any of claims 1 to 8 wherein the relative rotation between said first and second plate-like members proceeds smoothly.

11 A drip-feed head substantially as herein described.

12 A beverage-making appliance including a drip-feed head according to any preceding claim.