GB2102280A - Drip coffee maker - Google Patents

Abstract

In a drip coffee maker a reservoir 8 for water to be heated, a container 2 for ground coffee through which the hot water drips and a receptacle 9 for infused coffee are all contained within one vessel 1 which has a handle 6 and a spout 5. In the base of the drip coffee maker is a transfer heater 3 which boils water drawn from the reservoir 8 and raises it to the top of the container through a transfer tube 21, 22, 23 partly enclosed in the handle 6. A plate 29 in thermal contact with the heater 3 forms a heated floor of the receptacle 9 and of an extension of the receptacle 9 under the reservoir 8 to keep the infusion hot. The container 2 rests in a support 13 having an aperture 38 for pouring water into the reservoir 8. The drip rate can be altered by rotating the container 2 to bring different size openings 27, 27' into line with an outlet 28. In a modification infused coffee is received in a separate vessel within the main vessel and floats on the water in the reservoir descending as the water is transferred. <IMAGE>

Description

SPECIFICATION Drip coffee maker This invention relates to drip coffee makers, sometimes called filter coffee makers, in which the coffee is made by dripping hot water through ground coffee and a filter into a receptacle.

Drip coffee makers usually comprise a reservoir holding enough water to make the amount of coffee to be made, heating means for boiling the water and raising it to the top of the coffee maker, and a container for holding ground coffee. The hot water passes slowly down through the container and the infuses into it. The infusion flows through a filter paper, usually lining the container and drips into a receptacle below.

It is one disadvantage of many known drip coffee makers that the container is exposed to the surrounding cooling air and in consequence the temperature of the water drops appreciably as it passes through the ground coffee, and the infusion reaches the receptacle at a temperature somewhat below the ideal drinking temperature of about 800C. The receptacle in one known coffee maker is a carafe which stands on a heated plate incorporated in the coffee maker which re-heats the infusion and maintains it at the desired drinking temperature. An alternative arrangement which enables a large quantity of coffee to be made has the receptacle in the form of a thermally insulated jug. The thermal insulation alone is relied upon to keep the coffee hot in the jug.This is satisfactory when the coffee which has been made is to be used quickly, but if the coffee is left to stand in the jug for any length of time it cools down. If the amount of coffee to be made is less than the full capacity of the insulated jug, the effect of warming up the jug on the temperature of the coffee is even greater.

Another disadvantage of most known coffee makers is that they are designed as kitchen appliances and only the carafe or jug is intended to be taken to the table where coffee is to be poured. A carafe or uninsulated jug must be returned to the appliance if the coffee is to be kept hot and an insulated jug suffers from the shortcomings already described. While the carafe or jug is removed, in most known drip coffee makers, the coffee continues to drip from the container and is apt to make a mess. If there is a heated plate and the coffee drips onto that it is likely to leave a permanent stain.

A further disadvantage of these known drip coffee makers is that they have to be partially dismantled, including in some versions removal of the container, to enable the reservoir to be filled with water to be heated. This can be inconvenient and, especially when it is necessary to refill the reservoir after a quantity of coffee has already been made, it can be a messy procedure because of coffee drips still leaving the container.

The present invention seeks to provide a drip coffee maker which offers an improvement in at least some of these respects.

The present invention consists in a drip coffee maker comprising a vessel within which is located a reservoir for receiving water to be heated, a receptacle for infused coffee and a container for holding ground coffee which has an outlet to the receptacle, the drip coffee maker further comprising heating means for heating water drawn from the reservoir and for heating infused coffee received in the receptacle and a transfer tube through which water heated by the heating means can pass to the container.

The vessel may take the general form of a jug which has a lid which closes over the container and a spout with which the receptacle communicates for pouring coffee from the vessel.

As all the components of the coffee maker are contained within or mounted on the vessel the whole drip coffee maker can remain complete while coffee is being poured out. This enables a drip coffee maker according to the invention, with suitable design, to avoid many of the disadvantages previously discussed of known drip coffee makers in which the coffee receptacle has to be removed from the remainder of the appliance for pouring out.

A transparent window may be provided in the wall of the vessel or in the lid, to enable the interior to be seen, for example, to view the water dripping into, or the filtered infusion dripping out of, the container or to see how much coffee is left in the receptacle after pouring out.

The interior of the vessel may be divided horizontally into two compartments, which respectively form the reservoir and receptacle, by a dividing wall across the interior. The container may be supported over the dividing wall or the wall may be formed to locate and provide at least partial support for the container.

In another form of the invention the lower part of the interior of the vessel may form the reservoir for water to be heated, and an inner vessel which is adapted to float on the water in the reservoir may constitute the receptacle. Means may be provided which defines a lower limit to which this receptacle can descend in the vessel on the water.

For example, the receptacle may have an external flange or lip around its rim which, when the receptacle has descended to a certain level, rests on an internal ledge such as a shoulder formed on the inside of the vessel so that further descent of the receptacle is prevented. It is important that the receptacle should not move about in the vessel when coffee is being poured out. To inhibit the receptacle from moving holding means may be provided to hold the vessel at the lower limit of its movement. The holding means may be magnetic.

It may, for example comprise a permanent magnet or an electro-magnet mounted in the vessel at a position such that it acts on the receptacle or a suitable ferrous part thereof when the latter is at the lower limit, and holds the receptacle down.

The heating means may comprise an electrical resistance heating element, for example, of the tubular sheathed kind, arranged closely alongside a water tube and in good heat exchange relationship with the water tube, for example, by enclosing both within a casing cast around them. Alternatively the heating means may comprise an immersion or other suitable heater which is accommodated in or otherwise adapted to heat a chamber below the reservoir and in the water flow path between the reservoir and the transfer tube.

In addition to means, such as a fusible link, protecting the appliance from overheating if it boils dry, means may be provided for reducing the heat input to the coffee maker when its coffee-making cycle has been completed. This may merely disconnect the heating element and be manually resettable to re-heat the coffee or there may be a lower power "keep warm" element which is energised when the device is actuated to disconnect the main element or which is permanently in circuit. The device may be a switch which is thermally responsive or one operated mechanically or by other means to be later described.

A floor of the interior of the vessel may be heatable by the heating means. The heatable floor may form the bottom wall of the receptacle for heating infused coffee received in the receptacle.

Where the interior of the vessel is separated horizontally into the two compartments in the manner described above the dividing wall conveniently has a lower portion which forms an extension, below the compartment forming the reservoir, of the compartment forming the receptacle. The extension is heatable by the heating means, for example through the floor of the vessel where that is heatable by the heating means. The extension also spaces the reservoir compartment from the heatable floor or otherwise from the heating means.

In the arrangement described in which the receptacle is constituted by the inner vessel, when the receptacle gradually descends as the water from the reservoir is heated and transferred to the container, it is convenient to allow the vessel to descend to a level at which it too is heated by the heat from the heater, for example, through the floor of the vessel where that is heatable.

Although the transfer tube may extend to the container through the interior of the vessel, preferably it extends to the container through a handle of the vessel, or through a wall of the vessel, it being desirable that the tube should be enclosed and thermally insulated to reduce heat loss from the water in the tube. When the vessel has a lid which closes over the container, part of the transfer tube may be provided in the lid. The outlet from the transfer tube to the container may be at the lid.

The transfer tube may have an outlet which directs the water in a concentrated stream into the container, but preferably the outlet is adapted to spread the water over a wide area so that it is well dispersed through the ground coffee as it passes through the container. The outlet may be provided with a spreader plate, for example, which spreads the water over the container, or the outlet may take the form of a shower head or rose.

The container for ground coffee may be removably mounted in a support in the upper part of the vessel. The support may be removable from the vessel. Means may be provided for varying the rate at which the infusion drips from the container.

The means for varying the drip rate may be adjustable by an adjustable valve, for example.

Alternatively the means for varying the drip rate may afford a choice of pre-set rates. For example, drip openings of different sizes may be provided in the bottom of the container any of which can be brought into register with an outlet in the support, the unwanted opening or openings being blanked off.

Where the interior of the vessel is separated horizontally into two compartments an aperture may be provided in the support through which, after removal of the container, water can be poured into the reservoir shield to inhibit water from entering the compartment which is to serve as a receptacle for the infusion. The support is preferably arranged to divert water splashing onto it back into the reservoir compartment.

The drip coffee maker now provided offers improved heating of the coffee made in it. A primary reason for this is that the container for the ground coffee is located inside the vessel where it is insulated from cooling air. Thus the heated water which is filtered through the container retains much of its heat and the infusion reaches the receptacle at a higher temperature than in the known drip coffee makers which have their containers exposed to cooling air. Furthermore the fact that the reservoir and receptacle are both contained within the vessel along with the container improves the efficiency of the heating of the coffee and of keeping it hot, which can possibly save energy and reduce running costs.

A further advantage of the present invention is that the drip coffee maker can be made more compactly than known drip coffee makers, with fewer parts to be removed for filling and cleaning.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a central vertical section through a drip coffee maker in accordance with the invention.

Figure 2 is a section on line Il-Il of Figure 1, Figure 3 is an underside plan view, Figure 4 is a fragmentary section on line lV-IV of Figure 1 of a component of the coffee maker, and Figure 5 is a diagrammatic vertical section through another form of coffee maker according to the invention.

The drip coffee maker comprises a vessel 1 in the general form of a jug, a container 2 for ground coffee and an electrically heated transfer heater 3.

The vessel 1 has an upright body 4 of quartic cross-section with a spout 5 and, a handle 6 at opposite ends of the major axis of the quartic cross-section of the vessel which has a hinged lid 7. The body and lid are moulded from suitable plastics material. The interior of the vessel is separated horizontally into two compartments 8 and 9 by a partition wall 10 which has a main portion 11 which extends vertically parallel to the minor axis of the quartic cross-section of the vessel, from a lower portion 1 2 which extends the compartment 9 below the compartment 8. The compartment 8 constitutes a reservoir in the vessel for water to be heated. The other compartment 9, which is open to the spout 5, constitutes a receptacle for infused coffee.

The middle of the main portion 11 of the partition wall 10 does not extend to the top of the vessel but is cut away to admit a removable support 13 for the container 2. The support 13 occupies the upper portion of the vessel.

In the case of the vessel below the reservoir and receptacle compartments there is a chamber 14 which houses the transfer heater 3. An inlet 1 5 from the bottom of the reservoir compartment 8 leads into one end of a water tube 1 6 of the transfer heater for water to pass from that compartment into the heater to be heated by an electric heating element 30 of the tubular sheated type (Figures 1 and 3) enclosed together with the water tube 16 in a common casing 31 formed by a metal casting and secured, with good thermal connection, to a metal closure plate 29 for the bottom of the compartment 9. The price 29 forms a heatable floor of the vessel. A one-way valve 25 in the inlet 1 5 prevents water from passing from the heater back into the reservoir compartment.

The handle 6 extends for the height of the vessel. At its lower end it houses an appliance inlet 1 7 (Figure 3) for the electric supply for the heater.

The lid 7 is hinged to the top of the handle 6 about an axis 1 8 and is held closed by a latch (not shown) which is self-engaging on closing the lid and manually releasable to allow the lid to open.

The lid 7 completely closes off the top of the body.

To an outlet 20 of the transfer heater 3 is connected a feed pipe 21 which extends up through the handle 6 to the top of the body and mates through a releasable sealing connection 22 with a continuation passage 23 in the lid 7. The continuation passage 23 leads to a shower head 24 at the centre of the underside of the lid 7. The feed paper and continuation passage together constitute a transfer tube for conveying heated water from the transfer heater to the container 2.

When the lid is swung open the continuation passage 23 disconnects from the feed pipe 21 but the connection 22 sealingly joins them again when the lid is closed subsequently. As an alternative a single flexible pipe may provide the transfer tube instead of the feed pipe and continuation passage.

The removable support 13 for the container 2, at the top, has a shallow tray portion 32 the periphery of which is of quartic shape corresponding to the wall of the body 4. In the base of the tray there is a circular opening into a depending inverted, conoidal portion 33 which is circular at the top and has a diameter only slightly less than the minor axis dimension of the quartic tray portion so that the tray portion forms a ledge all round the circular opening. At its lower end the conoidal portion merges into a well 34 with a more upright, curved side wall. The well 34 has a substantially flat T-shaped, bottom wall 35 (Figure 4) the underside of which has a pair of parallel ridges 36 (Figure 1) forming between them a groove to receive the upper edge of the main portion 11 of the partition 10.The ridges 36 are continued to extend the groove up opposite sides of the side wall of the well 34. The cut away upper edge of the partition portion 11 is complementarily shaped to engage the groove throughout its length and so hold the support 13.

A lug 37 extends from the rim of the tray portion 32 over the handle 6 of the vessel to form a handle for lifting the support 13 from its place in the vessel. Most of the wall of the conoidal portion 33 is cut away on the side towards the handle 6 to leave a large aperture 38 above the reservoir 8.

The aperture extends down to the bottom wall 34 of the well on each side of a tongue 39 extending upwards from the end of the stem part of the T-shaped bottom wall. In preparing the coffee maker for use, water is poured through the aperture 38 into the reservoir 8. The wall of the conoidal portion 33 and the walls of the well 34 inhibit the entry of water into the compartment 9. A rib 40 extending upwards from the wall of the conoidal portion where it meets the side wall of the well 34 forms a trough to collect water, which splashes onto the wall of the conoidal portion, and divert it round the wall and through the aperture 38 into the reservoir 8.

The container 2 is also made as a plastic moulding. It is open topped and of complementary shape to the conoidal and wall portions of the support 13 in which it nests. Aflange 41 extends outwards from the upper edge of the container to overlap the edge of the circular opening and part of the ledge surrounding it. The bottom of the container 2 is generally complementary in shape to the well 34. The inside of the container 2 is shaped to contain, as a liner, a usual paper filter bag, indicated at 42 of modified conical shape.

Filter bags are usually made so that when opened out for use into generally conical form they have a bottom which is of rounded wedge shape. A floor 43 of the container 2 is formed with a hollow seating 44 suitably shaped to support the bottom of the filter bag and elongated in the direction of the minor axis of the quartic plan section of the vessel 4. On each side of the seating 44 there are cavities 45 open tops of which are covered by the filter paper 42. Drip outlets 27, 27' of different sizes are provided one in the bottom of each cavity 45. The container 2 can be fitted in alternative positions, one in which the drip outlet 27 is to be used and is in register with an aperture 28 in the bottom wall 35 of the well 34 and the other, with the container turned through 1 80C, to bring the drip outlet 27' into line with the aperture 28. The drip outlet not in use is blanked off by a seal plug 46 of rubber or suitable flexible material. When the lid 7 is closed and latched it bears on the top of the container 2 urging the mating parts of the sealing connection 22 together and the seal plug 46 against the drip outlet not in use.

For use of the drip coffee maker water is poured into the reservoir compartment. Markings may be provided in the body to show to what levels the compartment should be filled with water for the required numbers of cups of coffee. Typically the compartment is able to receive water for up to a maximum of 6 cups, i.e. approximately 2100 c.c. The water is poured in after removing the container but with its support 13 left in place. The ground coffee is put into the container after the latter has been lined with a suitable filter paper.

With the lid closed, the transfer heater 3 can then be switched on to heat the water which passes to the heater from the reservoir compartment by way of the inlet 1 5. The heated water is prevented from returning to the reservoir compartment by the one-way valve in the inlet 1 5 and is pumped by way of the feed pipe 21 and continuation passage 23 to the container, the shower head 24 spreading the water over the ground coffee. The infusion which filters out through the filter in the container drips out of the container through the drip outlet 27 or 27' in use and into the receptacle compartment through the aperture 28.Until it is to be poured out the infused coffee which collects in the receptacle compartment is kept hot by the heat transferred through the plate 29 from the transfer heater which may include a "keep-hot" element of lower wattage energised when the main element is switched off either manually or automatically for example by a thermostatic device.

A drip coffee maker as illustrated in Figures 1 to 4 is suitable for sizes up to about six cups, approximately 2100 c.c., but as each of the compartments 8 and 9 must be capable of holding the whole quantity while the other is empty, for larger sizes a drip coffee maker of this design may become too bulky.

The height and bulk of the drip coffee maker may be reduced, or its cup capacity increased, by replacing the conoidal container 2 and support 1 3 by nesting tray-like components with low upright peripheral walls and a cross-section in plan which is circular or corresponds more closely to the plan shape of the vessel to make good use of the space available. The cross-section may be quartic, for example. Filter papers of complementary shape would be used.

Figure 5 shows a modified form of drip coffee maker according to the invention which also overcomes this problem and so is particularly suitable for capacities above six cups although it is equally suitable for smaller capacities.

In Figure 5 components similar to those in Figures 1 to 4 have been given the same reference numerals and will not be described again.

The vessel body 51 is upright and stepped to form upper and lower parallel sided sections 52, 53 one above the other of similar cross-section which may be of circular, quartic or other noncircular shape. The upper section 52 is joined to the lower section 53 by a sloping ledge 54. A removable, conoidal container 59 for ground coffee and generally similar in form and function to the container 2 rests on a suitable support at the top of the upper section 52. The lower section 53 has at the bottom an inlet 1 5 to the transfer heater (not shown) by which water from the reservoir is heated and raised to drip through the ground coffee in the container 59. In use the vessel 51 contains water.

An open-topped receptacle 55 for the infusion floats on the water. It has a parallel-sided main part 56 the cross-section of which is similar to, but smaller than that of the lower section 53.

Around the rim of the receptacle 55 is a sloping flange 57 which extends over the ledge 54. The edge of the rim 57 is embraced by a seal 58 but this does not make sealing contact with the walls of the upper section 52 and the receptacle 55 is quite free to move vertically in the vessel 51.

The height of the receptacle 55 is such that when the receptacle 55 reaches the bottom of its travel, as the water in which it floats is transferred from the vessel 51, the seal 58 engages the ledge 54. A switch, not shown, actuated when the receptacle 55 reaches the bottom of its travel energises an electro-magnet 60 which attracts a plate 61 of ferro-magnetic material to keep the receptacle 55 at the bottom of its travel.

The switch may be actuated mechanically or by means of a proximity sensor responsive to the approach of the receptacle 55 to the bottom of the reservoir section 53. The switch may also switch off a main element of the transfer heater or energise a "keep-hot" heater element.

To prepare the drip coffee maker for making coffee, the container 59 and receptacle 55 are removed and the appropriate quantity of water poured into the lower section 53 and the water level may reach the upper section 52. The empty receptacle 55 is put back into the vessel 51 and floats on the reservoir. The container 59 is replaced in the top of the vessel 51, lined with a filter paper and filled with ground coffee.

The transfer heater heats the water and pumps it to the top of the container 59. The water passes through the ground coffee and the infusion drips into the floating receptacle 55. Initially the empty floating receptacle 55 may surround the container 59, but the combined effect of the lowering of the water level in the vessel 51 and the container's floating lower in the water as the infusion drips into it serves to keep the bottom of the container 59 out of contact with the infusion collecting in the receptacle 55. When the receptacle 55 reaches the bottom of its travel, indicated by broken lines in Figure 5, the electro-magnet 60 is energised and holds the receptacle 55 down.

When coffee is poured from the coffee maker it passes over the flange 57 to reach the spout. The electro-magnet 60 urges the seal 58 against the ledge 57 to close the joint and prevent the infusion from running back into the lower section 53. The electro-magnet also restrains the receptacle 55 from moving about during pouring.

Instead of an electro-magnet a permanent magnet may be provided. This would remain effective if the coffee maker were disconnected from the electric supply for pouring out coffee.

In the drip coffee maker illustrated in Figure 5, initially when the main vessel 51 is full of water, the empty receptacle 55 surrounds the coffee container 2 but when the receptacle 55 contains infused coffee it has moved down into the space in the vessel which previously contained water. It will be understood therefore that the total volume required for the coffee maker of Figure 5 is less than it would be if the water reservoir and the receptacle each occupied their own spaces even when empty and that the coffee maker resulting can be of large capacity yet compact.

Claims (32)

1. A drip coffee maker comprising a vessel within which is located a reservoir for receiving water to be heated, a receptacle for infused coffee and a container for holding ground coffee which has an outlet to the receptacle, the drip coffee maker further comprising heating means for heating water drawn from the reservoir and for heating infused coffee received in the receptacle and a transfer tube through which water heated by the heating means can pass to the container.

2. A drip coffee maker according to claim 1 wherein the vessel has the general form of a jug which has a lid which closes over the container and a spout with which the receptacle communicates for pouring coffee from the vessel.

3. A drip coffee maker according to claim 1 or claim 2 wherein a window is provided in the wall of the vessel or in the lid to enable the interior of the vessel to be seen.

4. A drip coffee maker according to any preceding claim wherein the interior of the vessel is divided horizontally into two compartments, which respectiveiy form the reservoir and receptacle, by a dividing wall across the interior.

5. A drip coffee maker according to claim 4 wherein the container is supported over the dividing wall or the wall is formed to locate and provide at least partial support for the container.

6. A drip coffee maker according to any one of claims 1 to 3 wherein the lower part of the interior of the vessel forms the reservoir and an inner vessel which is adapted to float on the water in the reservoir constitutes the receptacle.

7. A drip coffee maker according to claim 6 wherein means is provided which defines a lower limit to which the floating receptacle can descend in the vessel.

8. A drip coffee maker according to claim 7 wherein the means which defines the lower limit comprises an internal ledge formed on the inside of the vessel on which a projecting portion of the receptacle can rest.

9. A drip coffee maker according to any one of preceding claims 6 to 8 wherein means is provided for holding the receptacle against movement from its lower limit in order to resist movement of the receptacle while coffee is being poured from the vessel.

10. A drip coffee maker according to claim 9 wherein the holding means is magnetic.

11. A drip coffee maker according to any preceding claim wherein the heating means comprises an electric resistance heating element.

12. A drip coffee maker according to claim 1 wherein the heating element is of the tubular sheathed kind.

13. A drip coffee maker according to claim 12 wherein the tubula'r sheathed heating element is arranged in good heat exchange relationship with a water tube.

14. A drip coffee maker according to claim 13 wherein the tubular sheathed heating element and the water tube are embedded within a thermallyconductive casing cast around them.

1 5. A drip coffee maker according to claim 11 orclaim12 whereih the heating element is adapted to heat a chamber in the water flow path between the reservoir and the transfer tube.

16. A drip coffee maker according to any preceding claim wherein a floor of the interior of the vessel is heatable by the heating means.

17. A drip coffee maker according to claim 16 wherein the bottom wall of the receptacle is formed by the heatable floor of the vessel.

1 8. A drip coffee maker according to claim 1 6 or claim 1 7 as appendant to claim 4 wherein the dividing wall has a lower portion which forms an extension, below the compartment forming the reservoir, of the compartment forming the receptacle, the extension being heatable by the heating means and spacing the reservoir compartment from the heating means.

19. A drip coffee maker according to any one of preceding claims 11 to 17 as appendant to any one of claims 6 to 10 wherein at least at the lower limit of its movement the inner vessel is in a position to be heated by the heating means.

20. A drip coffee maker according to claim 1 9 as appendant to claim 1 6 wherein the bottom of the inner vessel is close to and capable of being heated by the heatable floor.

21. A drip coffee maker according to any preceding claim wherein the transfer tube extends to the container through the interior of the vessel.

22. A drip coffee maker according to any one of preceding claims 1 to 20 wherein the transfer tube extends to the container through a handle of the vessel.

23. A drip coffee maker according to any preceding claim wherein the container is removably mounted in a support in the upper part of the vessel.

24. A drip coffee maker according to claim 23 wherein the support is removable from the vessel.

25. A drip coffee maker according to any preceding claim wherein means is provided for varying the rate at which the infusion drips from the container.

26. A drip coffee maker according to claim 25 wherein the means for varying the drip rate is an adjustable valve.

27. A drip coffee maker according to claim 25 wherein the means for varying the drip rate affords a choice of pre-set rates.

28. A drip coffee maker according to claims 23 and 27 wherein drip openings of different sizes are provided in the bottom of the container any one of which can be brought into register with an outlet in the support, the unwanted opening or openings being blanked off.

29. A drip coffee maker according to claims 4 and 23 wherein the support is disposed over the dividing wall and an aperture is provided in the support through which, after removal of the container, water can be poured into the reservoir compartment, the support serving as a shield to inhibit the entry of water into the receptacle compartment.

30. A drip coffee maker according to claim 29 wherein the support is arranged to divert water splashing onto it into the reservoir compartment.

31. A drip coffee maker substantially as described herein with reference to, and as illustrated by, Figures 1 to 4 of the accompanying drawings.

32. A drip coffee maker substantially as described herein with reference to, and as illustrated by, Figure 5 of the accompanying drawings.