GB2199486A - Drip coffee maker - Google Patents

Abstract

A drip coffee maker has a vented outer chamber (3;3') which substantially surrounds a vented and heated an inner chamber (7;7'). The inner chamber comprises a receptacle for infused coffee flowing from a filter container (6;6') and the outer container comprises a reservoir for water. A flow heater (5;5') heats water taken from the reservoir (3;3') and urges it up a transfer pipe (4;4') from where it falls on ground coffee in the filter container. The floor of the inner chamber is a metal plate in thermal contact with the heating element (69) of the flow heater (5). A spout (12;104) communicates with the inner chamber. The spout is a composite spout providing an outlet for coffee (60) and inlet (64) for water to replenish the reservoir. The flow heater may comprise one tube inside another tube. <IMAGE>

Description

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 once through ground coffee and a filter into a receptacle.

The invention relates more particularly to electric drip coffee makers of the type comprising a vented reservoir holding enough water to make the amount of coffee to be made, a filter container for holding ground coffee, a transfer pipe leading from the reservoir through an electrically energised flow heater to the top of the filter container and a vented beverage receptacle to receive the infusion flowing from the filter container. Such drip coffee makers are hereinafter referred to as of the type described. Water in the reservoir is not significantly heated until it enters the flow heater and as the reservoir is vented pressure tending to expel the water is not developed in the reservoir by any heating which may occur.

In most drip coffee makers of the type described the beverage receptacle is a carafe which stands under an outlet from the filter container and is removable for pouring out. This type of coffee maker requires that the carafe is returned to the appliance to be kept hot by standing on a hot-plate. This is often remote from the place where the coffee is being served.

In addition, in current types of filter coffee makers of the type described - it is difficult to maintain the coffee at a temperature suitable for drinking. This is because the coffee is infused in a filter remote from any heat source. Also the water or infused coffee has to pass through air of ambient temperature between the transfer pipe and the filter container for the ground coffee and between the filter container and the carafe.

The present invention aims to overcome at least some of the previously mentioned disadvantages.

Drip coffee makers of the type described have been proposed in Patent Application 2 102 280 which comprise a single vessel which includes both the reservoir and the beverage receptacle side by side, the complete vessel being manipulated for pouring out the infused coffee.

The present invention consists of an electric drip coffee maker having an upright body, an electrically energised flow heater, a transfer pipe, and a filter container for holding ground coffee, the upright body comprising an inner chamber, an outer chamber at least partially surrounding the inner chamber, a spout having an outlet connected by a passage to the inner chamber, and an upwardly directed filler opening into the outer chamber; the transfer pipe leading from the outer chamber through the flow heater to the top of the filter container, the outer chamber comprising a vented reservoir for water and the inner chamber comprising a heated and vented beverage receptacle and receiving the infusion flowing from the filter container.

The reservoir can be filled under a water tap through the upwardly directed filler opening which may also serve as a vent for the reservoir. The filler opening may also be used to empty the reservoir. After infusion, coffee can be poured from the outlet opening of the spout.

The outer chamber at least partially surrounding the inner chamber affords a double-wall construction for the inner chamber tending to decrease the heat losses and consequent running cost.

The body may be moulded in plastics material.

The spout may be a compound spout which includes both the filler opening and the outlet opening, the filler opening being separated from the outlet opening and being open to the outer chamber.

The inner chamber may project across the outer chamber to interrupt the circumferential continuity of the outer chamber. The outer chamber may have a C-shaped cross section.

An upper part of the interior part of the spout may be partitioned off to form a well -open to the filler opening. A wall of the well may be provided with one or more apertures which communicate with the outer chamber to allow water to enter the reservoir.

Preferably a handle is attached to the coffee maker by a collar which may be of C-shaped cross-section. The spout may extend through the gap in the C-shaped cross-section.

The inner chamber is preferably heated through its floor by an electric heating element of the flow heater. The floor of the inner chamber may be formed by a metal plate, or metal plate assembly, in thermal conductive relationship with the electric heating element. The metal plate may be minted in the body by a seal which not only resists fluid leakage but allows the metal plate and the flow heat or other component mounted on the metal plate to be removed for servicing or replacement. Where the body of the vessel is moulded in plastics material the seal may be such as to afford thermal insulation to protect the plastics body from being overheated.

The transfer pipe may pass up through the inner chamber. Such an arrangement further improves heat conservation. The transfer pipe may also pass through the wall of the filter container to an outlet above the maximum level to which the filter container is likely to be filled with ground coffee. The filter container may have a conical base provided with mesh forming the filter medium and which surrounds an upright tube telescoping with the upper end of the transfer pipe arranged centrally. The upright tube may incorporate a spreader to distribute water evenly in the filter and prevent entry of coffee into the transfer pipe during the filling of the filter with ground coffee.

The lower end of the bore of the transfer pipe is open to the outer chamber and is preferably provided in that region with a non-return valve to resist flow of water from the flow heater back into the reservoir.

The flow heater may comprise a loop of the transfer pipe near the inlet end arranged in close thermal conductive relationship with a sheathed electric resistance heating element. The loop may be removably but seal ably connected to the part of the transfer pipe which passes through the inner chamber.

The flow heater may conveniently be arranged below the floor of the inner chamber, the heating element being sandwiched between the loop of transfer pipe and the floor of the inner chamber. The cross-section of the sheath of the heating element in this region may be shaped to follow the contour of the transfer pipe loop and fit against the undersurface of the floor so as to increase the areas of contact between the sheath and the floor and the loop of the transfer pipe to which it may be brazed or otherwise secured in a manner to assist heat transfer by conduction.

Alternatively the flow heater may comprise an outer wall enclosing a sheathed electric heating element and defining a flow passage for water between the sheath of the heating element and the inside surface of the outer wall. The outer wall may hug the sheath of the heating element for a substantial circumferential extent of the sheath.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings of which: Figure 1 is a central vertical cross-section of a coffee maker constructed in accordance with the invention, taken on line I-I of Figure 2, Figure 2 is an underneath plan view of the coffee maker of Figure 1 with its base member removed, Figure 3 is a fragmentary vertical cross-section taken on line III-III of Figure 2, Figure 4 is a horizontal cross-section taken on line IV-IV of Figure 1.

Figure 5 is an exploded perspective view from above of another coffee maker constructed in accordance with the invention, and Figure 6 is an exploded perspective view from beneath of the flow heater assembly of the coffee maker of Figure 5.

The coffee maker shown in the Figures 1 to 4 of the drawings essentially consists of a generally cylindrical vessel whose axis is disposed vertically in use. The vessel has a handle 1 and a spout 2 and defines a generally annular outer chamber comprising a fresh water reservoir 3 for holding fresh water from which leads a transfer pipe 4 for transferring water heated by a flow heater 5 to a point above a filter 6 where the hot water may fall upon ground coffee situated in the filter and be infused, the infused coffee then passing through the filter 6 to be retained in an inner chamber defined by a generally cylindrical beverage receptacle 7.

The reservoir 3 and receptacle 7 are substantially defined by a main casing part 8 which is a single component of plastics material moulded, for example, from polypropylene, as best shown in Figures 1 and 4.

The general form of casing 8 is that of a predominantly cylindrical structure which extends vertically in use and which is of a double walled construction comprising an inner wall 9 and an outer wall 10.

The inner wall 9 comprises a circularly curved portion 11 which extends circumferentially for 360 , and a projecting spout portion 12 which extends outwards from the curved portion 11 in a generally radial direction. The spout portion 12 comprises two parallel side walls 13 and 14 joined at their radially outermost extent by an end wall 15. End wall 15 slopes away from the centre of the coffee maker at its uppermost region 16.

Towards the lower third of the receptacle 7 the curved portion 11 of the inner wall-9 is provided with a generally triangular portal opening 17 which extends through the wall. This portal opening is of the form of an isosceles triangle symmetrically located with respect to the vertical symmetrical plane of the spout, with its apex directed downwardly. The portal 17 allows infused coffee in the bottom of the reservoir to enter the bottom of the spout portion 12. The upper side of the triangular portal 17 is substantially the same width as the internal width of the spout portion 12. The downwardly directed apex of the portal is rounded and is spaced slightly above the lower edge of the casing 8.

The outer wall 10 has the generl form of a circular C-shaped wall radially spaced from and concentric with the curved portion 1 of the inner wall 9, each of the open ends of the arms of the "C" meeting a respective one of the side walls 13 and 14 of the spout portion 12 and being integral with them. The spout portion 12 projects outwards of the outer wall 10 over most of the vertical extent of the coffee maker.

However, the lower region 18 of the vertical outer wall 10 has an increasing radius as it approaches the lower part of the coffee maker to give the external appearance of the coffee- maker a generally frusto-conical shape in that region. The end wall 15 and the spout portion 12 of the outer wall are co-planar towards the lower region of the coffee maker. The handle 1 is formed integrally with the casing 8 diametrically opposite thesspot: F 9 Although the outer wall issgenerally of C-shape it is interrupted by a recess 19 extending vertically for most of the length of the coffee maker.The recess 19 is defined by two parallel partition walls 20 and 21 which are circumferentially spaced and extend radially from the outer wall to the curved portion of the inner wall, and that part of the inner wall which extends between the partition walls. The recess 19 is angularly displaced approximately 900 from both the handle 1 and the spout 2 and serves to accommodate a transparent water-level indicator 22 in such a way that the outer surface of the water-level indicator lies flush with the outer surface of the outer wall. The partition walls 20 and 21 are formed integral with the casing 8. An inwardly projecting annular lip 23 extends from the lowermost portion of the inner wall 9. The annular lip 23 extends completely through 3600.

The lower end of the reservoir 3 formed by the double-walled construction of the casing is closed by an annular closure plate 24 retained to the bottom of the casing, as for example by sonic welding. The closure plate 24 seals the bottom of the annular fresh water reservoir 3 and also partly defines an electrical components enclosure 25 located below the reservoir 3 and receptacle 7. The annular closure plate 24 has upwardly directed circular flanges 26,27 slightly set back from its inner and outer circumferential edges.

These flanges 26 and 27 assist in locating the annular closure plate relative to the bottom of the casing 8 and help to provide a good seal when the closure plate 24 is welded to the casing. The casing 8 and the annular closure plate 24 define the reservoir 3.

A base member 28, which has the general form of a cylindrical bowl is detachably secured to the underside of the closure plate 24. The base member 28 has a base portion 29 and a circumferential wall 30 which is provided with an internal rebate 31 at its upper edge. Bosses 32 and 33 provided respectively projecting from the upper surface af the base portion of the base member 28 and from the lower surface of the annular closure plate 24 enable the base member 28 to be screwed to the closure plate and thereby releasably retain the base member to the remainder of the coffee maker. The base member defines apertures 34 and 35 for switch and plug-socket assemblies 36, 37 respectively.

As shown in Figure 3 the recess 19 of the casing 8 is terminated at its lower end by the annular closure plate 24 which connects the outer wall to the inner wall and also the two partition walls 20 and 21. The closure plate 24 has a hole 38 extending vertically through it. The hole 38 provides a passage for a screw 39 to extend from the underside of the closure plate and engage a downwardly depending boss 40 provided on the underside of the- water level indicator 22 to retain the water-level indicator to the closure plate. The water level indicator has a hole 41 which allows water to flow between the reservoir 3 and the inside of the water-level indicator.

The transfer pipe 4 is made of aluminium and extends from the electrical components enclosure 25 up through an aperture in an aluminium earthing plate 42 which is clamped to a stainless steel hot plate 43.

The earthing and hot plates together define a floor assembly of the beverage receptacle 7. The plates are clamped together by studs and nuts 44 and 45 respectively. The hotplate 43 is of circular dish-shape and has a radially outwardly directed flange 46. The flange 46 is supported by a sealing and insulating grommet 47 made of silicone rubber which engages and grips the annular lip 23 of the casing.

The transfer pipe is constructed of an upper part 48 and a lower part 49 which are releasably, but sealably, joined together in the region of the hotplate 43.

Where the transfer pipe 4 passes through the floor assembly, the hotplate 43 has a raised dome which and the earthing plate 42 have aligned openings. Before the hotplate 43 and earthing plate 42 are fastened together the upper part 48 of the transfer pipe 4 is inserted into the aperture in the hotplate 43. The lower end of the upper part 48 is outwardly flanged and a sealing gasket 50 is placed between the flange and the inside of the dome. The upper end of the lower part 49 is passed through the aperture in the earthing plate 42 and inserted into the bore of the upper part 48, a further gasket 50 around the upper end of the lower part 49 being interposed between the flange on the upper part 48 and the earthing plate 42. When the earthing plate 42 and hotplate 43 are secured together, the gaskets 50 seal both apertures and the joint between the two parts of the transfer pipe.

The upper part 48 of the transfer pipe extends from the hotplate to a point towards the top of the coffee maker above the filter 6. At its uppermost third the upper part 48 of the transfer pipe is concentric with the curved portions of the inner and outer walls, but towards the middle region of the beverage receptacle and approximately to specific coffee levels, it is kinked away from the central axis of the coffee maker so that the lower third of the upper part 48 of the transfer pipe, although vertical, is displaced from the concentric position.

The filter is formed of plastics material such as polypropylene and comprises a cylindrical upper portion 51 from which depends a downwardly directed frusto-conical operative nylon mesh portion 52. A hollow locating sleeve 53 extends upwards from the truncation of the frusto-conical operative portion 52.

The sleeve 53 is detachably fitted over the upper end of the transfer pipe. A spreader 54 consisting of a cap spaced from the end of the sleeve 53 by three struts is provided at the upper end of the sleeve. The outer periphery of the filter is provided with an annular flange which locates against a ledge 55 provided at the top of the casing. Lugs 56 are provided on the underside of the filter to enable it to stand upright when removed from the coffee maker and placed a level surface.

The transfer pipe has a circumferential flange 57 spaced from its upper end. A three--legged spider 58 rests on the flange 57. The spider 58. serves both to centre the transfer pipe concentrically: with the beverage receptacle and to indicate the maximum level to which the reservoir can be filled.

The spout 2 is a compound spout and gas a well 59 in communication with the water reservoir 3, and an outlet 60 through which coffee can be poured. The well 59 is defined by the upper part of the spout portion 12 of the casing 8 and a dividing wall 61 which is sealed to the spout portion by means such as sonic welding.More specifically, the well is.defined by the uppermost part of two opposite side walls 13 and 14 of the spout portion, a back-wall portion 62 of the inner wall 9 which extends between the sidewalls 13 and 14, a floor- wall 63 extending away from the back-wall portion 62 and connecting the two side walls 13 and 14, and the dividing wall 61 which extends upwardly between the back-wall and the uppermost region of the end wall 15 of the spout portion from the radially outer edge of the floor-wall 63 and across the width of the spout from wall 13 to wall 14. The side walls 13 and 14 are provided with apertures 64 in the region where the back-wall meets the floor wall. These apertures 64 open into the upper part of the water reservoir 3. Thus the well 59 serves as a filler opening for the coffee maker.The dividing wall 61 may be located by runners or grooves prior to welding.

The dividing wall 61 is spaced from the sloping uppermost region 16 of the end wall, and the passage between the radially outer face of the dividing wall and the radially inner face of the region 16 of the end wall defines an outlet for infused coffee. It will be appreciated that the floor wall 63 and the dividing wall 61 separate the water inlet from the coffee-containing part of the spout. The floor-wall may be formed to have a central peak so as to avoid splash-back during filling.

The back-wall 62 is provided on its radially-inward face with an open-topped groove 67. A detachable cap 65 seats at its periphery on the upper peripheral edge of the casing. The cap is provided with two pegs 66 located below the level of its seating with the casing. One of the pegs locates in groove 67 of the back wall portion 62 and the other in an open topped groove 68 provided in the casing diametrically opposite the groove 67. The grooves 67 and 68 may be L-shaped to provide the cap and the casing with a bayonet connection which retains the cap by twisting.

Thus it will be apparent that the beverage receptacle 7 comprises an inner chamber principally defined by the following parts: the inner surface of the curved portion 11 and the spout portion 12 of the inner wall 9 and the hotplate 43. The fresh water reservoir 3 comprises an outer chamber principally defined by the radially outer surface of the curved portion 11 of the inner wall 9, the radially inner surface of the outer wall 10, the upper surface of the annular closure plate 24 the partition walls 20, 21 of the recess 19, and the interior of the water level indicator 22. The sonic welding of the annular closure plate 24 to the casing 8 along the seams where they contact provides a water-tight seal between these two main plastics components which define the reservoir 3.

This seal prohibits water, or infused coffee, from entering the electrical components enclosure 25.

The electrical components enclosure contains the flow heater 5 which comprises a horizontally disposed U-shaped sheathed electrical . resistance heating element 69 connected in an electrical circuit to the switch assembly 36 and plug-socket assembly 37. The heating element 69 is held against the earthing plate 42 to facilitate heat transfer via that plate to the hotplate 43. Directly below the heating element 69, and abutting against it, is the lower part 49 of the transfer pipe which is formed in a loop so as to closely follow the shape of the heating element to maximise heat transfer to this lower part of the transfer pipe. In order to do this the lower part 49 extends radially outwards towards the handle and then bends to come back on itself and follow one of the arms of the "U" of the heating element, following it right around the "U" as shown in Figure 2. The heating element 69 is shaped in the regions of the transfer pipe and the earthing plate so as to increase its area of contact with these components.

A tubular elbow 70 of silicone rubber extends from free end 71 of the transfer pipe and is bent upwards towards the annular closure plate 24 and passes through an aperture 72 provided in that plate and into the freshwater reservoir 3 to enable water to enter the transfer pipe. A grommet portion 73 provided at the end of the elbow 70 seals the aperture 72 against the entry of water into the electrical components enclosure. A one-way ball valve 74 is provided in the elbow adjacent the end 71 of the transfer tube and comprises a cage 75 having a valve seat 76 and a ball 77 retained in the cage. The valve prevents water which is being heated in the transfer pipe from re-entering the water reservoir.

A thermostat 78 and a fusible link 79 are also included in the electrical circuit of the heating element. The thermostat 78 has a metal base from which extends a metal clip 80 which is screwed to the earthing plate. The clip 80 has a semi-circular hook part which supports a part of the lower part 49 of the transfer pipe, following the circumference of the pipe for substantially 180 . The clip 80 also abuts the heating element 69. This arrangement means that the thermostat experiences a composite temperature influenced by the temperature of the heating element, the temperature of the transfer pipe, and also to a small extent the temperature of the earthing plate and the hot plate. Another metal clip 81 holds the fusible link, so that it lies against both the heating element and the transfer pipe.Again, the temperature of the fusible link which is provided to protect against overheating of the heating means, is influenced by the temperature of both the heating element and the transfer pipe.

Access to the electrical components enclosure 25 can be achieved by removing the base member 28.

Because all the operative parts of the coffee maker are retained within this enclosure access for maintenance is simple.

S' The operation of the coffee maker will now be described by way of further explanation.

Water is poured into well 59 from where it enters the top of the water reservoir 3 and flows to the bottom of the reservoir. As much or as little water as is required to accommodate the desired number of cups of coffee is poured in. Cap 65 is removed, a suitable amount of ground coffee placed on the frusto-conical portion of the filter 6 and the cap replaced. The water enters the transfer pipe 4 by means of the one-way valve 74, water pressure opening the valVe until the levels of water in the transfer pipe and water reservoir are equal. The coffee' maker is then switched on.

The heating element 69 heats the lower part 49 of the transfer pipe which in turn heats the water contained within it. As the temperature of the water in the transfer pipe increases the vapour pressure above it increases, increasing the pressure at the ball valve which therefore closes. The water in the transfer pipe is at that stage trapped in the pipe and continues to increase in temperature until it boils.

As it boils the rising steam lifts the water up the transfer pipe and a mixture of steam and boiling. hot water is forced out of the upper end of the pipe and is spread by the spreader 54 to fdll on the ground coffee in an evenly distributed mannZer.* The hot water is then infused and filters through the filter to enter the beverage receptacle 7. The arrangement of the transfer pipe inside the beverage receptacle and of the beverage receptacle inside the water reservoir increases the energy-efficiency of the coffee maker.The transfer pipe carries boiling water during the filtering process and therefore assists in heating the coffee in the receptacle 7, also any heat lost from the coffee already infused partway through the process passes predominantly to the water in the reservoir 3, via the inner wall, and so is not lost to the system as a whole. When the transfer tube and the coffee receptacle lose heat during the filtering operation they pass it usefully on to another part of the system so that it is not wasted. Because the triangular portal 17 in the inner wall is large the infused coffee located in the spout portion 12 is kept hot by the hotplate.

As the water trapped in the transfer pipe boils and is forced out of the pipe, the pressure in the transfer pipe drops and the water pressure due to the head of water in the water reservoir forces the valve open allowing another quantity of water to enter the loop of the transfer pipe and the process then repeats itself. When all the water in the water reservoir has been transferred and any water remaining in the transfer tube loop converted to steam, the clip 80 is no longer cooled by heat being drawn into water in the transfer pipe and thus the temperature of the clip increases. The thermostat senses this rising temperature and switches off the heating element. An alternative would be to reduce the power of the heating element to a level to maintain the temperature of the clip, but not increase it.

When the infused coffee is retained in the receptacle 7, it is heated by the hotplate 43 which is in thermal contact with the heating element. The heat conducted to the hotplate and the heat losses from the coffee reservoir are so arranged that the temperature of the coffee in the receptacle is maintained at the desired level by the thermostat cycling the heating element on and off.

It should be noted that the hotplate does not directly contact the plastics casing of the coffee maker since the heat could be too great for the plastics. Instead, as well as its sealing function, the grommet 47 serves to insulate the casing from the hotplate.

When the coffee has been infused it is poured out of the spout defined by the outer face of the dividing wall 61 of the spout insert and. the inner face of the upper region 16 of the spout portion 12. The lid may then be removed and the filter lifted out and cleaned.

The filter can stand upright on its lugs 56 when stood upon a flat work-surface. The arrangement of the spout ensures that if the coffee making operation is stopped part-way through so that there remains some water in the water reservoir the coffee can be poured out without the water leaving the water reservoir via the well because the exit for the coffee is lower when pouring than the entrance for the water.

The provision of the spout projecting through the water reservoir increases the volume of the beverage receptacle. The coffee maker is therefore compact, and has a minimum unused space.

The spacing of the lowest point of the apex of the portal 17 from the bottom end of the inner wall ensures that the closure plate 24 can be adequately seal ably welded to the bottom of the inner wall for the entire 3600 extent of the closure plate.

The coffee maker shown in Figures 5 and 6 is similar to the coffee maker of Figures 1 to 4, but incorporates various modifications. Similar structures are given similar references numerals.

Casing 8' and closure plate 24' define between each other a reservoir 3' for water, extending around a beverage receptacle 7'. The casing 8' comprises a frustro-conical outer wall 10' and an axially extending inner wall 9'. The outer wall 10' merges with the inner wall 9' at a line about two-thirds of the way up the height of the casing 8'. A cylindrical mounting portion 100 is defined above the outer wall 10'.

The inner wall 9' has a "key-hole" cross-section at its lower region near the closure plate and extends generally vertically upwards to the mounting portion 10 which comprises a continuation of the inner wall.

The inner wall 9' defines a generally cylindrical central portion 102 of receptacle 7', and a projecting portion 103 which extends to the peripheral edge of the vessel at a position diametrically opposed to a spout 104. The projecting portion 103 is adjacent a 'handle 105. Spout 104 is defined by the inner wall 9' and extends across the cross-section of the receptacle in a transverse projection diametrically opposed to the portion 103. The spout extends vertically upwards.

The frustro-conical outer wall 10' has its central axis concentric with and superimposed upon the central axis of the cylindrical portion 102 of the inner wall. The reservoir 3' has a generally C-shaped cross-section, with the gap of the C being towards the handle. The spout 104 is within the area of the outer wall 10' at the lower region of the vessel, but is transversely beyond the sloping wall 10' at the upper regions of the wall 10'. The usable volumes of the reservoir 3' and receptacle 7' are substantially equal.

Handle 105 is mounted on the vessel by means of a collar 106 moulded integrally with the handle. The collar 106 is of cylindrical form and extends through approximately 3000 to define a gap 107. The collar has substantially the same vertical extent as the mounting portion 101 and has a downwardly extending, inwardly overturned, flange 108 formed at its upper edge. The collar locates around the mounting portion 101 with the flange 108 hooked over the upper wall of the mounting portion. The spout 104 is located in the gap 107.

Inwardly projecting pegs 109 are provided on the flange 108 and co-operate with formations on cap 65' to provide a bayonet connection. A switch (not shown) is provided in the handle 105. The lower end of the handle is registered with an upwardly extending channel 110 defined by the casing 8' and the closure plate 24'.

The upper end of the spout 104 is adapted in a similar way to the coffee maker of Figures 1 to 4 to provide a composite spout having a lower orifice through which coffee is poured and a well having an orifice (or orifices) through which water is poured into the reservoir 3'. The apertures corresponding to apertures 64 are not shown, but their form will be readily apparent, for example the spout could have a flared double-wall construction in its region above the outer wall 10'.

The flow heater assembly of the coffee maker of Figures 5 and 6 is a little different to that shown in Figures 1 to 4. Flow heater 5' comprises a U-shaped tubular sheathed heating element 69 enclosed by a outer tube 111 of figure-of-eight section. As best shown in Figure 6, the element 69' is retained in one bulb of the figure-of-eight whilst the other defines a flow passage 112.

The outer tube 111 is in close thermal engagement with the element 69' for approximately 200 of the circumference of the element with which transfer pipe 4' communicates. Flexible boots 113 and 114 close the ends of the outer tube 111. Boot 113 passes through the closure plate 24' and communicates one end of the flow passage 112 with the reservoir 3' via a one way valve. Boot 114 communicates the other end of the flow passage 112 with the vertically extending transfer pipe 4' via a rubber hose (indicated at 115).

An additional tray 116 is provided beneath the outer tube 111 to support it In a further embodiment the inner wall may be conical and the outer wall cylindrical.

Claims (20)

1. An electric drip coffee maker having an upright body, an electrically energised flow heater, a transfer pipe, and a filter container for holding ground coffee, the upright body comprising an inner chamber, an outer chamber at least partially surrounding the inner chamber, a spout having an outlet connected by a passage to the inner chamber, and an upwardly directed filler opening into the outer chamber; the transfer pipe leading from the outer chamber through the flow heater to the top of the filter container, the outer chamber comprising a vented reservoir for water and the inner chamber comprising a heated and vented beverage receptacle and receiving the infusion flowing from the filter container.

2. A coffee maker according to claim 1 in which the transfer pipe extends through the inner chamber.

3. A coffee maker according to claim 1 or claim 2 in which the inner chamber has a central axis and the outer chamber has a central axis substantially co-incident with the central axis of the inner chamber.

4. A coffee maker according to claim 3 in which the outer chamber is defined in part by a frustro-conical outer wall.

5. A coffee maker according to claim 3 or claim in which the transfer pipe has a central axis which is also substantially co-incident with the central axes of the inner and outer chambers, at least for a part of the vertical extent of the coffee maker.

6. A coffee maker according to any preceding claim in which the spout is a compound spout which includes both the filler opening and the outlet opening, the filler opening being separated from the outlet opening and being open to the outer chamber.

7. A coffee maker according to claim 5 or claim 6 in which an upper part of the interior part of the spout is partitioned off from the outlet to form a well open to the filler opening, a wall of the well having one or more apertures which communicate with the outer chamber to allow water to enter the reservoir.

8. A coffee maker according to any preceding claim in which the interior of the spout forms an enlargement of the inner chamber extending across the outer chamber.

9. A coffee maker according to any preceding claim in which the chambers are substantially defined by two components of plastics materials, a main part and a base member, the main part defining the major portion of the chambers and the base member closing off the bottom of at least the outer chamber.

10. A coffee maker according to any preceding claim in which at least a part of the floor of the inner chamber is formed by a metal plate assembly in thermal conductive relationship with an electric heating element of the flow heater.

11. A coffee maker according to claim 10 in which the joint between the floor of the inner chamber and the body includes a seal which not only resists fluid leakage but affords thermal insulation to protect the body from being overheated.

12. A coffee maker according to any preceding claim in which the inner chamber projects across the outer chamber to interrupt the circumferential continuity of the outer chamber.

13. A coffee maker according to claim 12, in which the outer chamber has a substantially C-shaped cross section at least at some region of the coffee maker.

14. A coffee maker according to any preceding claim in which the coffee maker is provided with a handle which is mounted on the coffee maker by means of a mounting collar.

15. A coffee maker according to claim 14 in which the collar is C-shaped in section and .the spout extends in the region of the gap in the C-shaped section.

16. A coffee maker according to any preceding claim in which the flow heater comprises an outer wall enclosing a sheathed electric heating element and defining a flow passage for water between the sheath of the heating element and the inside surface of the outer wall.

17. A coffee maker according to claim 16 in which the outer wall hugs the surface of the sheath of the heating element for a substantial circumferential extent of the sheath.

18. A coffee maker according to any preceding claim in which the filler opening .Iorthe .outer chamber also comprises the vent for the nnter chamber.

19. An electric coffee maker stbstantially as herein described with reference to Figures 1 to 4 of the accompanying drawings.

20. An electric drip coffee maker substantially as herein described with reference to Figures 5 and 6 of the accompanying drawings.