WO2000044267A1

WO2000044267A1 - Electrical beverage making apparatus

Info

Publication number: WO2000044267A1
Application number: PCT/GB2000/000289
Authority: WO
Inventors: John Crawshaw Taylor
Original assignee: Strix Limited
Priority date: 1999-01-29
Filing date: 2000-01-28
Publication date: 2000-08-03
Also published as: GB9902085D0; AU2122200A; GB2346074A

Abstract

A beverage maker comprises a water heating chamber (1) for heating water and receiving a beverage; and infusion chamber (2) in which, in use, the beverage is infused, the infusion chamber (2) being in fluid communication with the water heating chamber (1); a passage (22) extending between the water heating chamber (1) and the infusion chamber (2) for allowing water to flow into the infusion chamber (2) from the water heating chamber (1), the passage (22) having a passage outlet (36) located in an upper part of the infusion chamber (2) such that, in use, water enters the infusion chamber (2) without passing through liquid already in the infusion chamber (2), and a return flow path (27) for allowing the infused beverage to pass from the infusion chamber (2) into the water heating chamber (1). This prevents steam passing through the infusing beverage after heated water has passed into the infusion chamber (2). The beverage therefore has improved flavour.

Description

Electrical beverage making apparatus

The present invention relates to electrical beverage making appliances and in particular, but not exclusively, to electrical coffee makers.

A known coffee maker comprises a water heating chamber and an infusion chamber arranged above the water heating chamber in which ground coffee is placed and infused into the water. The chambers are connected by a passage which extends downwardly from the infusion chamber into the water heating chamber. A filter, in the form of a ribbed bung or weight sits in the opening between the passage and the infusion chamber and allows water to flow into and out of the infusion chamber while retaining the ground coffee in the infusion chamber. In use, the water heating chamber is filled with cold or hot water and the water is heated in the water heating chamber by an external heater, for example a gas or spirit flame or an electric element arranged under the chamber. As the water is heated, pressure in the water heating chamber increases causing water to rise up the passage through the filter and into the infusion chamber where it infuses with the ground coffee. When the level of water in the water heating chamber falls below an opening through which water enters the passage, transfer of water into the infusion chamber stops and air and steam can escape, in the form of bubbles, through the beverage infusing in the infusion chamber. Heating continues for a few moments to drive all the air out of the water heating chamber so that the space within the water heating chamber contains mostly steam. Heating is then discontinued and, as the water heating chamber cools, steam begins to condense within the water heating chamber. This results in a reduction of pressure within the water heating chamber resulting in suction of the brewed coffee in the infusion chamber through the passage and the filter back into the water heating chamber. When all of the beverage has been sucked out into the water heating chamber, the infusion chamber is generally removable so that the beverage can be served from the water heating chamber.

Such appliances are disclosed in GB1332656 and in our co-pending British Patent Application No. 9825961.7. However, such appliances suffer from various problems and it is the object of the present invention to overcome these problems.

In particular, as stated above the passage between the two chambers in a conventional beverage maker of this type generally terminates at an opening in the base of the upper infusion chamber where the bung or weight is located. Ground coffee is placed in the infusion chamber and lies above the bung or weight . Heated water therefore passes up through the ground coffee into the infusion chamber for infusion. However, after the transfer of liquid has finished, steam continues to be produced in the water heating chamber which thus passes up into the infusion chamber through the infusion of coffee and water. This is detrimental to the flavour of the beverage produced as the steam passing through the coffee infusion extracts bitter oils from the coffee grounds. Furthermore, the end of water flow into the infusion chamber tends to be abrupt and immediately followed by steam at high pressure. The steam can cause the coffee infusion to spill out of the coffee maker and possibly injure a user unless a suitable lid is provided.

In one aspect the invention seeks to overcome these problems and according to a first aspect of the present invention there is provided a beverage maker comprising: a water heating chamber for heating water and receiving the beverage; an infusion chamber in which, in use, the beverage is infused, the infusion chamber being in fluid communication with the water heating chamber; a passage extending between the water heating chamber and the infusion chamber for allowing water to flow into the infusion chamber from the water heating chamber, the passage having a passage outlet located in an upper part of the infusion chamber such that, in use, water enters the infusion chamber without passing through liquid already in the infusion chamber, and a return flow path for allowing the infused beverage to pass from the infusion chamber into the water heating chamber.

This arrangement has the advantage that steam is prevented from passing through the beverage infusion when entering the upper chamber and the beverage produced has improved flavour since it too will be exhausted into an upper part of the infusion chamber. Furthermore, there is no risk of unwanted ejection of the beverage infusion from the infusion chamber, unlike the prior art . The infusion chamber is preferably arranged above the water heating chamber, although it would be possible to have the chambers on the same level .

Preferably, the beverage maker has a filter for filtering the infused beverage as it flows, in use, from the infusion chamber through the return path and into the water heating chamber.

As liquid therefore enters and exits the infusion chamber by different flow paths, this has the advantage that the beverage maker may be provided with a filter more efficient than those of the prior art as it is only required to pass fluid in a single direction from the infusion chamber to the water heating chamber.

The passage outlet may have means for causing the water to enter the infusion chamber with a flow arranged to agitate liquid in the infusion chamber. The flow may be downward and/or rotational.

The return path may be completely separate from the passage, comprising for example a pipe extending around the passage and opening directly into the water heating chamber. Preferably, however, it comprises a channel which extends downward from the base of the infusion chamber around the passage and is connected with the passage by one or more apertures in the passage wall thereby using the passage as part of the return path. The wall of the passage may have one or more further apertures externally sealed with a diaphragm, the diaphragm being arranged to block the return path when pressure in the water heating chamber is greater than or equal to the pressure in the infusion chamber so as to prevent fluid flowing from the infusion chamber into the passage via the return path when the water is heated and also to prevent heated water entering the infusion chamber via the return path.

The channel may be substantially annular and concentric with the passage. The diaphragm may then also be substantially annular and radially expandable to block the channel when the pressure in the passage is greater than the pressure in the infusion chamber. The passage may conveniently comprise a lower section extending downwardly and preferably formed integrally with the infusion chamber and an upper snorkel section extending upwardly and preferably removably attachable to the lower section. The return path may then be formed by an annular cavity between the upper snorkel section and a top part of the lower section when the upper snorkel section is attached to the lower section.

Amongst other advantages, the removability of the upper section facilitates cleaning of the infusion chamber, and may also allow the snorkel section to be retro-fitted to known beverage makers. The snorkel section may also conveniently mount the filter. The filter may be integrally formed with the snorkel section or be removably attachable to the snorkel section. Thus, the filter may also be easily removed and cleaned and modular manufacture can reduce manufacturing cost .

It will be appreciated that when the water heating chamber cools, the pressure drop in the water heating chamber should not be dissipated. Thus, the passage may also have a non-return valve for preventing fluid or gas from entering the passage from the infusion chamber through its outlet when pressure in the passage is less than pressure in the infusion chamber. The valve may be positioned at the top of the snorkel section and may most simply be a ball valve.

As mentioned above, a known filter comprises a bung in a hole with either the surface of the bung or the surface of the hole in contact with the hole or the bung respectively provided with tapering ribs which allow a limited fluid flow. Generally, the ribs are virtually horizontal. Thus, filtering occurs essentially through larger particles of ground coffee or the like becoming trapped in the ribs and acting as the filter. These filters have the problem that, if the ribs are wide, small particulate matter is not effectively filtered and enters the water heating chamber with the infused beverage. However, if the ribs are narrow, these filters become easily blocked and have very limited fluid flow. Any filter of this type inevitably compromises between these two problems, solving neither. Furthermore, a longer filtering time increases the chance of a leak developing and stopping suction into the water heating chamber. In a filter of the prior art the beverage will then stop flowing through the filter and remain in the infusion chamber.

Also, if a blockage develops, the pressure reduction in the water heating chamber may be so great as to implode the chamber if there is any defect in the chamber wall.

The invention also seeks to overcome these problems, and according to a second aspect of the present invention there is provided a beverage maker comprising: a water heating chamber; an infusion chamber; one or more passages between the water heating chamber and the infusion chamber for allowing infused beverage to flow, in use, from the water heating chamber to the infusion chamber and from the infusion chamber to the water heating chamber, and; a filter positioned between the infusion chamber and the water heating chamber, the filter comprising a substantially horizontally arranged mesh.

Thus, the filter may have a large surface area which is not prone to blocking and has an improved rate of fluid flow. This reduces the overall time in which the beverage is made compared to the prior art. Furthermore, any risk of the water heating chamber imploding due to blockage is eliminated. Also, a very fine mesh may be used in the filter which, when combined with suction provided by the reduced pressure in the water heating chamber when heating is stopped, provides very effective filtering. Preferably the filter comprises a polyester mesh supported on a frame which may be plastic or the like.

The perimeter of the frame may be shaped to form a tight seal with part of the inner wall of the infusion chamber.

The frame may than be supported by contact between its perimeter and the part of the inner wall of the infusion chamber, and retained in position by resilient means such as a spring connected to an anchorage point such as the lower rim of the flow passage. Such a filter may be simply substituted for existing solid ribbed filters, which use a similar fixing means.

Alternatively, in the arrangements described above, where a section of the passage extends into the infusion chamber, the frame may be substantially annular and arranged around the passage. The section of the passage may be removable from the infusion chamber and/or the filter may be removable from the section of the passage to facilitate cleaning.

A further problem with known beverage making apparatus of this type is that, during water heating, water begins to flow between the water heating chamber and the upper infusion chamber before the water boils in the water heating chamber. This is because the difference in pressure between the water heating chamber and the infusion chamber need only be sufficient to overcome the relatively small height difference between the two chambers before water begins to flow. Typically water begins to flow into the infusion chamber from about 60°C. Water therefore tends to flow slowly into the infusion chamber and the grounds tend to form lumps and balls which reduce contact with the water and inhibit infusion. Further, the beverage begins to infuse at a low temperature and the time it takes the beverage to infuse is undesirably long. The best flavour of the beverage may not be achieved and the resulting beverage may not be sufficiently hot.

According to a third aspect of the present invention there is provided a beverage maker comprising: a water heating chamber; means for heating water in the water heating chamber; an infusion chamber arranged in fluid communication with the water heating chamber; a passage between the water heating chamber and the infusion chamber, and; flow control means in, or in fluid communication with, the water heating chamber which, as water heats in the water heating chamber allows air and vapour to escape at such a rate initially as to maintain the pressure difference between the water heating chamber and the infusion chamber at a level too low to cause water to flow into the infusion chamber, but subsequently at a rate insufficient to prevent the pressure in the water heating chamber rising to the extent that water flows into the infusion chamber.

Thus, as the water is heating, vapour pressure which otherwise would have caused the water to rise up into the infusion chamber is released, allowing the water to get hotter before it enters the infusion chamber. Thus, infusion time is shortened, the flavour of the beverage is enhanced and the temperature of the finished beverage is raised relative to the prior art. Furthermore, when water begins to flow into the infusion chamber, it flows more rapidly, improving dispersion of the coffee grounds.

The flow control means may comprise a venting hole in a wall of the water heating chamber which allows expanding air and steam to escape to the atmosphere . Thus, water can be heated and produce steam up to the certain rate without an increase in pressure in the water heating chamber sufficient to cause water to rise up the passage into the infusion chamber. However, when the water in the water heating chamber is boiling, more steam is produced in the water heating chamber than can escape through the hole and the pressure difference between the water heating. chamber and the infusion chamber begins to increase . Water then starts to flow up the passage and into the infusion chamber. The hole may preferably have a diameter of around 0.6 mm. The venting hole may be in an external wall of the water heating chamber, although this may be undesirable for a number of reasons. Firstly, it may produce a jet of steam which might injure a user. Secondly, to prevent air being sucked into the water heating chamber and thus dissipating the suction developed in the water heating chamber, the flow control should have a non-return valve which may comprise, for example, a rubber seal arranged over the hole, displaceable to allow air and steam to escape but arranged to seal so as to prevent air from entering the water heating chamber through the hole as soon as the pressure in the water heating chamber drops. Preferably, therefore the flow control means may comprise an opening between the water heating chamber and the infusion chamber. This opening may conveniently discharge into the passage between the chambers. This has the advantage of dispersing steam escaping from the beverage maker gently into the infusion chamber, rather than as an external jet, thus improving safety. Furthermore in the preferred embodiment described above, the need to provide a further non return valve to prevent air flow into the water heating chamber is obviated, since such a value is already provided in the passage.

Another problem of conventional beverage making apparatus of this type is that the seal between the upper infusion chamber and the water heating chamber is difficult to achieve without employing an annular rubber seal which is radially compressed when a bung of one chamber is placed in a hole of the other chamber to join the chambers. Thus, particularly after use of the apparatus which may result in expansion of various components of the beverage maker and in the bung being sucked further into the hole, it can be difficult to separate the two chambers to pour the finished beverage. Furthermore, a bung in a hole does not provide accurate location of the chambers. According to a fourth aspect of the invention, there is provided a beverage maker comprising :- a water heating chamber; an infusion chamber mountable in fluid communication with the water heating chamber; a connector for connecting the water heating and infusion chambers such that fluid can flow between the water heating and infusion chambers, wherein the connector is sealed by an annular member which is axially compressed between two axially facing surfaces to form a seal when the water heating and infusion chambers are connected. The seal may be formed between the annular member and one or both of the axial surfaces and/or by radial expansion of the annular member causing it to press against a radial surface.

This has the advantage that the infusion chamber is easy to remove as the annular member does not need to be tight fitting in a radial direction. An axial compression force may also act to push chambers apart, thereby making removal easier.

The chambers may be held together and the compression force sealing the connector maintained by a releasable fastening such as a bayonet type fitting which may preferably be elliptical. Alternatively a screw thread or the like may be employed.

Preferably, the chambers each have a handle. The handles facilitate fixing and removal of the bayonet or screw fitting and separation of the connector and chambers .

The handles may be arranged to be aligned when the connector is correctly connected, for example when the bayonet fitting is fully engaged. This has the advantage of indicating to a user that the chambers are properly connected.

According to a fifth aspect of the present invention there is provided a beverage maker comprising: - a water heating chamber; an infusion chamber mountable in fluid communication with the water heating chamber; a connector for connecting the water heating and infusion chambers, wherein the infusion chamber has a handle in order to facilitate the separation of the connector and removal of the infusion chamber from the water heating chamber.

Thus, the infusion chamber may be easily handled preventing unnecessary spillages and breakages.

As above, the handles may be arranged to be aligned when the connector is correctly connected, for example when the bayonet fitting is fully engaged. This has the advantage of indicating to a user that the chambers are properly connected.

A yet further problem with existing coffee makers of the kind described earlier is that after the coffee has infused, and the infusion chamber has been removed from the water heating chamber, the infusion chamber, which will contain wet, spent, coffee grounds must be stored temporarily prior to cleaning. This is inconvenient, may leave an unsightly mess, and furthermore possibly damage the infusion chamber.

The present invention also seeks to overcome this problem and from a yet further aspect provides a beverage maker comprising: a water heating chamber; and an infusion chamber mountable in fluid communication with the water heating chamber, said infusion chamber being provided with a removable lid which is adapted to support said infusion chamber after the infusion chamber is removed from the water heating chamber.

With this arrangement, the lid, preferably in an inverted position acts as a stable support and a drip tray for the infusion chamber after it has been removed from the water heating chamber.

In the preferred embodiment described above, the underside of the lid may be formed into a formation to receive an end of a water transfer passage.

Preferred embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side view of a coffee maker according to the present invention;

Figure 2 is a cross sectional side view of the coffee maker illustrated in Figure 1;

Figure 3 is a side view of an upper infusion chamber of a coffee maker according to the invention;

Figure 4 is a cross sectional view along line A-A of a passage of the upper infusion chamber illustrated in Figure 3 ;

Figure 5 is a cross sectional view of a connection between an upper infusion chamber and a lower water heating chamber of a coffee maker according to the invention;

Figure 6 is a cross sectional view of the top of a snorkel for a coffee maker according to the invention; Figure 7 is an exploded view of a snorkel for a coffee maker according to the invention;

Figure 8 is a side view of the snorkel illustrated in figure 7;

Figure 9 is a cross sectional side view of the snorkel illustrated in figure 7, at 90° to the view in figures 7 and 8, with a filter attached;

Figure 10 is a plan view of a filter for a coffee maker according to the invention;

Figure 11 is a side view of a lid for an infusion chamber of a coffee maker according to the invention, inverted to form a base for the infusion chamber, and;

Figure 12 is a cross sectional view of a stopper for a spout of a water heating chamber of a coffee maker according to the invention. Referring to Figures 1 and 2, there is provided a coffee maker having a lower water heating chamber 1 and an upper infusion chamber 2. The water heating chamber 1 and infusion chamber 2 are removably connected by a connector 3, shown in Figure 2, at a spout 4 of the water heating chamber 1. The water heating chamber sits on a base 5 having a cordless electrical connector 6 arranged on its upper surface for engagement with a corresponding connector under the base of the water heating chamber 1, which includes a heater 7 under its base. Both the chambers 1, 2 have handles 8, 9, the infusion chamber has a lid 10 but is generally in fluid communication with the atmosphere, and the water heating chamber 1 has a window 11 with level indicators 12 for helping a user to judge the level of water in the chamber 1.

As can also be seen from Figure 2, a pipe extends from adjacent the top of the infusion chamber 2 to the base of the water heating chamber 1. The pipe mounts a filter and, as will be described further below, is provided with valves arranged to allow heated water to pass into the infusion chamber 2 from the water heating chamber 1 and infused coffee beverage to flow back into the water heating chamber 1.

Referring now also to Figures 3, 4 and 5, in use, water is placed in the lower chamber 1 through the spout 4. The upper chamber 2 is then mounted on the lower chamber 1. Mounting is achieved by inserting a male member 13 of the connector 3, which in this example is formed integrally with the infusion chamber 2, with a female member 15 of the connector 3 provided on the spout 4 of the lower chamber 1. The infusion chamber 2 is then rotated through an angle of 90° relative to the lower chamber 1 using the handles 8, 9 so that an elliptical bayonet fitting 16, illustrated in Figure 4, on the male member 13 engages below a lip 17 of the female member 15. Alternatively, the bayonet fitting 16 may engage with receiving slots (not shown) in the female member 15.

The handles 8, 9 on the infusion chamber 2 and water heating chamber 1 respectively are aligned when the connector 3 is properly connected. In this embodiment, the elliptical bayonet fitting 16 has a protrusion 18 on its upper axial surface and the lip 17 has a recess (not shown) . In this example, the protrusion 18 is a half cylinder formed integrally with the elliptical bayonet fitting 16. The protrusion 18 and recess are positioned to engage when the infusion chamber 2 has been rotated through the 90° angle, the handles 8, 9 are aligned and the connector 14 is properly connected.

An annular rubber member 19 is axially compressed between a first lip or axial surface 20 on the male member 13 and a second lip or annular surface 21 on the female member 15 when the infusion chamber 2 is joined to the water heating chamber 1 and the connector 3 is secured. This ensures a seal between the upper chamber 2 and the lower chamber 1 by compressing the member 19 so that it both forms a seal with the annular surfaces 20, 21 and expands radially to seal with an inner radial wall of the female member 15, so as to prevent vapour escaping from the spout 4.

The pipe is, more specifically, a passage 22 for flow of water between the water heating chamber 1 and the infusion chamber 2. The passage 22 is formed by a lower section 24 and an upper section 23 which is a separate component removably connected to the lower section 24 of the passage 22 by a snap fit arrangement. With reference to Figure 2, the snap fit arrangement comprises recesses 25 provided in the outer surface of the upper section 23 at the lower end of the upper section 23, and corresponding protrusions 26 provided on the inner surface of the lower section 23, such that the recesses 25 and protrusions 26 engage when the upper section 23 is connected to the lower section 24 to retain the upper section 23 in place.

The upper section 23 extends almost to the top of the infusion chamber 2. The lower section 24 is, as shown, a pipe integrally formed with the infusion chamber 2.

An annular channel 27 is formed between the outer wall of the upper section 23 and the inner wall at the top of the lower section 24. The channel 27 extends from an opening 28 in the base of the infusion chamber to a lip 29 on the inner wall of the lower section 24. The upper section 23 has two elongate holes 30, proximate to the lip 29 when the upper section is in place, which provide fluid communication between the channel 27 and the passage 22.

A filter insert 31 is placed in the infusion chamber 2. In this example, the filter insert 31 is a planar annulus arranged to fit around the upper section 23 of the passage 22 and is generally fitted to the upper section 23 for ease of insertion and removal . When in place, the filter insert 31 fits in sealing engagement with the outer surface of the upper section 23 and the inner surface of the infusion chamber 2 above the opening 28 in the base of the infusion chamber 2. The filter 31 is, in this example, provided in snap fit engagement with the upper section 23.

Coffee is then placed in the infusion chamber 2 and rests on the filter 31. Alternatively a receptacle is provided in the infusion chamber 2 for holding the coffee . The receptacle may take the form of a measure .

The water is then heated. It is preferable that the heater 7 is operated in the manner described in our co-pending British Patent Application No. 9825961.7. As the temperature of the water increases air in the water heating chamber 1 expands, air in the water comes of solution and steam is produced. The air exits through a flow control or vent 32, shown in Figure 5, which in this example comprises a hole between the water heating chamber 1 and the annular channel 27, and therefore connects the water heating chamber 1 and the passage 22 via the elongate holes 30. Steam can pass through the vent 32 at a certain rate and pass through the passage 22 into the top of the upper chamber 2 and into the atmosphere. Thus, the pressure in the water heating chamber 1 and passage 22 remains essentially the same until steam starts to be produced in the lower chamber 1 at a rate above that at which steam can pass through the vent 32. Pressure then begins to rise in the lower chamber 1 to a level sufficiently greater than that in the passage 22 to cause water to be pushed, through an opening 33 in the bottom of the passage 22 up the passage 22, from the lower chamber 1 into the infusion chamber 2.

As water is pushed through the opening 33 and up the passage 22, a valve 34, illustrated in Figure 6, at the top of the passage 22 releases to allow water to enter the upper chamber 2. In this example, the valve 34 comprises a weighted bung 35 resting in an opening 36. The bung 35 is displaced by water rising up the passage 22. However, when pressure in the passage 22 is lower than that in the upper chamber 2, the bung 35 seals the opening 36 to help maintain the lower pressure in the lower chamber 2.

As hot water flows into the infusion chamber 2 , it flows onto coffee grounds located in the infusion chamber 2 and the coffee grounds begin to infuse with the hot water. If a receptacle is provided for holding the coffee, this may release the coffee when the hot water enters the infusion chamber 2. After a certain period of time the water level in the lower chamber 1 drops below the opening 33 and water stops flowing into the infusion chamber 2. It should be noted that a small quantity of water may remain in the lower chamber 1 in accordance with the method and apparatus described in our co-pending British Patent

Application No. 9825961.7 and other prior art devices. Steam may continue to be produced to expel all the air from the water heating chamber 1. This exits through the passage 22 into the top of the infusion chamber 2 and into the atmosphere.

The heater 7 is then turned off and the water heating chamber 1 cools. As cooling begins and pressure within the chamber 1 decreases due to condensation within the chamber. As mentioned above, as the pressure in the chamber 1 decreases the pressure also decreases in the passage 8, and the ball valve 9 seals. As described above, the vent 32 may be arranged to close when pressure in the water heating chamber 1 falls. However, in this example the vent 32 communicates with the passage 22, which is sealed by the valve 34 at the top of the passage 22 when pressure in the water heating chamber 1 is less than atmospheric pressure .

A valve 37 comprising, in this example, an annular diaphragm 38 located in the side wall of the upper section 23 of the passage 22, below the opening 28 at the base of the upper chamber 2 when the upper section 23 is in place, resiliently presses against the inside wall of the lower section 24 to block the channel 27. The diaphragm 38 also covers holes 39 in the side of the passage 22 such that the blocking of the channel 27 is enhanced by an outward radial force caused by the pressure difference between the passage 22 and the infusion chamber 2 whilst water is rising into the infusion chamber 2. However, whilst there is a pressure in the passage 22 lower than that in the infusion chamber 2, the valve is sucked radially inwards by the pressure difference. This unblocks the channel 27 and the infused beverage begins to flow through the filter 31 down the passage 22 into the water heating chamber 1. In this example, blockage of the channel 27 occurs at a lip 40 positioned on the inner wall of the lower section 24 in the channel 27 such that a larger area of the diaphragm is between the passage 22 and a portion of the channel 27 in communication with the infusion chamber 2, than between the passage 22 and a portion of the channel 27 in communication with the passage 22 via holes 30 and the vent 32. This ensures that the diaphragm moves to block or unblock the channel 27 in reaction to the pressure difference between the passage 22 and the infusion chamber 2.

As mentioned above, the upper section 23 of the passage 22 is preferably removably fitted in the infusion chamber 2. An example of the removable upper section 23 or snorkel is illustrated in Figures 7 to 9. The upper section 23 has protrusions 41 which rest on the lip 29 of the lower section 24 when the upper section 23 is in place. The top of the upper section 23 has an opening 36 for receiving the bung 35 as described above. A cap 42 is provided for retaining the bung 35 in the opening 36.

Below the opening 36 are vanes 43 formed on the outside of the under section 23. Above, and in fluid communication with, the vanes 43, swirl vanes 44 may be provided. The vanes 43, 44 are arranged such that as water exits the opening 36, it is deflected by the inside of the cap 42 and flows through the vanes 43, 44. The shape of the cap 42 and the vanes 43, 44 may be designed to cause water to flow down the outer surface of the upper section 23, either vertically or helically or, when the cap is larger, as a sheet of spray flowing as a generally conical helix. The rotational motion of the water stirs the infusion of water and coffee grounds .

As shown in Figure 8, level indicating marks 45 are provided on the outside of the upper section 23. Also, as shown in Figure 9, the filter 31 is arranged to removably fit with the upper section 23. The filter 31 comprises, in this example, a fine polyester mesh 46 insert moulded into a plastics frame 47, as illustrated in Figure 10. The mesh 46 is, in this example, a PA 56/31 mesh and the frame 47 is made of plastic in the spiral arrangement illustrated, which enhances fluid flow and reduces blocking.

As the pressure difference between the chambers 1 and 2 increases the infused beverage is sucked through the polyester mesh 46 at a rate greater than that would be caused only by gravity and efficient filtering is achieved.

After the infusion is complete, the infusion chamber 2 may be removed from the lower chamber 1 by rotating the chamber 2 through an angle of 90° by using the handle 8 on the infusion chamber 2. This has the effect of dislodging the elliptical bayonet fitting 16 from beneath the lip 17. The axial compression force on the rubber seal acts to push the chambers 1, 2 apart and the seal is easily broken. After the removal of the infusion chamber 2, the beverage may be poured freely from the lower chamber 1.

As illustrated in Figure 11, the lid 10 of the infusion chamber 2 may be removed and inverted. It is designed to form a stable platform on feet 47 and has a receiving section 48 which enables the lid 10 to fit to the infusion chamber 2. Thus, the infusion chamber 2 may be stored safely prior to cleaning. A cap 49, as illustrated in Figure 12, can be placed in the spout 4. The cap 49 comprises a weighted ball 50 of suitable dimensions with a handle 51. The heating chamber 1 is thus suitable as a serving receptacle.

Of course it will be understood that the above is a description of a preferred embodiment only, and that modifications may be made thereto without departing from the scope of the invention. For example, the vent may comprise a hole in the side wall of the lower chamber 1 which allows steam to exit to the atmosphere directly from the water heating chamber 1. The diameter of the hole may, in this example, have a diameter of 0.6 mm. The hole is preferably at the top of the dome of the water heating chamber 1, under the handle 8 of the infusion chamber, as this reduces the risk of a user being scolded by escaping steam. The hole allows steam produced initially by the heated water to exit the lower chamber 1 at the same rate as it is produced, with the result that there is no significant net increase in pressure within the chamber 1. However, when the temperature of the water increases to around boiling point, steam is not able to escape from the chamber 1 at the same rate as it is produced and the pressure within the lower chamber 1 increases . The pressure in the infusion chamber 2 remains substantially at atmospheric pressure. Thus, the pressure difference between the two chambers 1, 2 increases and water rises into the upper chamber 2. A non-return valve (not shown) is provided over the hole in the form of a rubber flap or band mounted externally over the hole. Thus, when pressure within the water heating chamber 1 is less that atmospheric pressure, the hole is sealed and no air enters the water heating chamber 1.

Claims

Claims :

1. A beverage maker comprising: a water heating chamber for heating water and receiving a beverage; an infusion chamber in which, in use, the beverage is infused, the infusion chamber being in fluid communication with the water heating chamber; a passage extending between the water heating chamber and the infusion chamber for allowing water to flow into the infusion chamber from the water heating chamber, the passage having a passage outlet located in an upper part of the infusion chamber such that, in use, water enters the infusion chamber without passing through liquid already in the infusion chamber, and a return flow path for allowing the infused beverage to pass from the infusion chamber into the water heating chamber.

2. The beverage maker of claim 1, wherein the infusion chamber is located above the water heating chamber.

3. The beverage maker of claim 1 or claim 2 , further comprising a filter for filtering the infused beverage as it flows, in use, from the infusion chamber through the return path and into the water heating chamber.

4. The beverage maker of any one of the preceding claims, wherein the passage outlet has means for causing water to enter the infusion chamber with a flow arranged to agitate liquid in the infusion chamber.

5. The beverage maker of any one of the preceding claims, wherein the return path comprises a channel which extends downward from the base of the infusion chamber around the passage and is connected with the passage by one or more apertures in the passage wall thereby using the passage as part of the return path.

6. The beverage maker of claim 5, wherein the channel is substantially annular and concentric with the passage.

7. The beverage maker of claim 5 or 6, wherein the wall of the passage has one or more further apertures externally sealed with a diaphragm, the diaphragm being arranged to block the return path when pressure in the water heating chamber is greater than or equal to the pressure in the infusion chamber.

8. The beverage maker of claim 7, wherein the diaphragm is substantially annular and radially expandable to block the channel when the pressure in the passage is greater than the pressure in the infusion chamber .

9. The beverage maker of any preceding claim, wherein the passage comprises a lower section extending downwardly from the infusion chamber and an upper snorkel section extending upwardly from, and removably attachable to, the lower section.

10. The beverage maker of claim 9, wherein return path is formed by an annular cavity between the upper snorkel section and a top part of the lower section when the upper snorkel section is attached to the lower section.

11. The beverage maker of claim 9 or claim 10 as dependant directly or indirectly on claim 3, wherein the filter is mounted on the snorkel section.

12. A beverage maker comprising: a water heating chamber; an infusion chamber; one or more passages between the water heating chamber and the infusion chamber for allowing infused beverage to flow, in use, from the water heating chamber to the infusion chamber and from the infusion chamber to the water heating chamber, and; a filter positioned between the infusion chamber and the water heating chamber, the filter comprising a substantially horizontally arranged mesh.

13. The beverage maker of claim 12, wherein the filter comprises a polyester mesh supported on a frame .

14. A beverage maker comprising: a water heating chamber; means for heating water in the water heating chamber; an infusion chamber arranged in fluid communication with the water heating chamber; a passage between the water heating chamber and the infusion chamber, and; flow control means in, or in fluid communication with, the water heating chamber which, as water heats in the water heating chamber allows air and vapour to escape at such a rate initially as to maintain the pressure difference between the water heating chamber and the infusion chamber at a level too low to cause water to flow into the infusion chamber, but subsequently at a rate insufficient to prevent the pressure in the water heating chamber rising to the extent that water flows into the infusion chamber.

15. The beverage maker of claim 14 , the flow control means comprising a venting hole in a wall of the water heating chamber which allows expanding air and steam to escape to the atmosphere.

16. The beverage maker of claim 14 , the flow control means comprising an opening between the water heating chamber and the infusion chamber.

17. A beverage maker comprising: - a water heating chamber; an infusion chamber mountable in fluid communication with the water heating chamber; a connector for connecting the water heating and infusion chambers such that fluid can flow between the ^• water heating and infusion chambers, wherein the connector is sealed by an annular member which is axially compressed between two axially facing surfaces to form a seal when the water heating and infusion chambers are connected.

18. The beverage maker of claim 17, the seal being formed between the annular member and one or both of the axial surfaces and/or by radial expansion of the annular member causing it to press against a radial surface.

19. The beverage maker of claim 17 or claim 18, the chambers being held together and the compression force sealing the connector maintained by a releasable fastening.

20. The beverage maker of claim 19, wherein the fastening is an elliptical bayonet type fitting.

21. The beverage maker of any one of claims 17 to 20, wherein the chambers each have a handle, and the handles may be arranged to be aligned when the connector is correctly connected.

22. A beverage maker comprising: - a water heating chamber; an infusion chamber mountable in fluid communication with the water heating chamber; and a connector for connecting the water heating and infusion chambers, wherein the infusion chamber has a handle in order to facilitate the separation of the connector and removal of the infusion chamber from the water heating chamber.

23. A beverage maker comprising: a water heating chamber; and an infusion chamber mountable in fluid communication with the water heating chamber, said infusion chamber being provided with a removable lid which is adapted to support said infusion chamber after the infusion chamber is removed from the water heating chamber.

24. The beverage maker of any preceding claim, substantially as described with reference to the accompanying drawings .