FLUID HEATING APPLIANCE

Abstract

A coffeemaker generally includes a reservoir and a flow control system for regulating a flow of water from the reservoir. The flow control system has a thin-film heating element that defines at least a portion of a heating conduit in which water is heated.

Description

BACKGROUND

The present invention relates generally to fluid heating appliances and, more particularly, to an appliance for brewing a beverage (e.g., a coffeemaker).

Many conventional coffeemakers have a water reservoir, a showerhead, and a flow control system. The flow control system includes an arrangement of tubes and a pump for generating a flow of water from the reservoir to the showerhead through the tubes. At least some conventional coffeemakers also include a calrod-type heating device that heats the water as the water flows from the reservoir to the showerhead. However, it can be difficult to regulate water temperature with calrod-type heating devices, not to mention the less than desirable heat-up time and bulkiness of calrod-type heating devices.

It would be useful, therefore, to provide a coffeemaker with a smaller heating device that enables water to be heated quicker and to a more precise temperature.

SUMMARY

In one embodiment, a coffeemaker generally comprises a reservoir and a flow control system for regulating a flow of water from the reservoir. The flow control system includes a thin-film heating element that defines at least a portion of a heating conduit in which water is heated.

In another embodiment, a coffeemaker generally comprises a reservoir, a showerhead, and a flow control system for regulating a flow of water from the reservoir to the showerhead. The flow control system includes a thin-film heating element that defines a heating conduit in which water is heated. The flow control system further includes a check valve disposed between the reservoir and the heating element, and a flow control valve disposed between the heating element and the showerhead.

In yet another embodiment, a terminal unit for a heating device having a pair of tubular, thin-film heating elements generally comprises a pair of ring-shaped terminals each sized to wrap around one of the heating elements. The terminal unit also includes a bus bar extending between the ring-shaped terminals to electrically connect the ring-shaped terminals to one another.

BRIEF DESCRIPTION

FIG. 1 is a perspective view of one embodiment of a fluid heating appliance;

FIG. 2 is a side view of the fluid heating appliance of FIG. 1;

FIG. 3 is the side view of FIG. 2 with a side panel of the appliance housing removed;

FIG. 4 is a cross-sectional view of the fluid heating appliance of FIG. 2 taken along plane 4-4 of FIG. 2;

FIG. 5 is a perspective view of a heating device of the fluid heating appliance of FIG. 4;

FIG. 6 is a perspective view of a terminal unit of the heating device of FIG. 5;

FIG. 7 is a cross-sectional view of a heating element of the heating device of FIG. 5;

FIG. 8 is an enlarged portion of the cross-sectional view of FIG. 7 taken within area 8;

FIG. 9 is a schematic illustration of an embodiment of a flow control system for use in the fluid heating appliance of FIG. 3;

FIG. 10 is a perspective view of an embodiment of a heating device and associated showerhead for use in the fluid heating appliance of FIG. 3; and

FIG. 11 is a cross-sectional view of the heating device and showerhead of FIG. 10.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Referring to the drawings, and in particular to FIGS. 1 and 2, a fluid heating appliance is illustrated in the form of a coffeemaker (indicated generally by the reference numeral 100). It is contemplated that, in other embodiments, the fluid heating appliance may be any suitable type of appliance that heats fluid (i.e., gas or liquid) for any suitable purpose without departing from the scope of this invention (e.g., the fluid heating appliance may be a hot water dispenser in some embodiments).

The illustrated coffeemaker 100 includes a housing 102, a filter basket 104 detachably mounted on (e.g., suspended from) the housing 102, and a hot plate 106 situated beneath the filter basket 104. In this manner, the coffeemaker 100 is configured to receive a carafe (e.g., a coffee pot 108) on the hot plate 106 beneath the filter basket 104 for containing a brewed beverage (e.g., coffee) discharged from the filter basket 104 during a brewing operation.

To enable viewing of internal componentry of the coffeemaker 100 during its operation, at least one window is provided on the housing 102, namely a pair of opposing first windows 110 and a pair of opposing second windows 112 in the illustrated embodiment. In other embodiments, however, the coffeemaker 100 may be configured in any suitable manner that facilitates enabling the coffeemaker 100 to heat liquid as described herein (e.g., the coffeemaker 100 may not have the detachable filter basket 104, the hot plate 106, and/or the windows 110, 112 in some contemplated embodiments).

With reference now to FIG. 3, the illustrated coffeemaker 100 further includes a reservoir 114, a showerhead 116, and a flow control system (indicated generally by reference numeral 118) for regulating a flow of liquid from the reservoir 114 to the showerhead 116. The reservoir 114 is configured to contain a liquid suitable for brewing a beverage (e.g., water), and the amount of liquid contained within the reservoir 114 is observable through the first windows 110. The showerhead 116 is situated, at least in part, above the filter basket 104 for discharging liquid onto a brewable product (e.g., coffee grounds) placed on a filter inside the filter basket 104.

The flow control system 118 includes a pump 120, a holding tank 122, and a heating device (indicated generally by reference numeral 124) connected in flow communication with one another by a suitable network of conduits. In the illustrated embodiment, the network includes: an upstream conduit 126 which connects the reservoir 114 to the pump 120; a column conduit 128 which connects the pump 120 to the holding tank 122; a downstream conduit 130 which connects the holding tank 122 to the heating device 124; and a ventilation conduit 132 which connects the holding tank 122 to the exterior of the housing 102 for ventilating the network to the ambient. Alternatively, the flow control system 118 may have any suitable components arranged in any suitable manner that facilitates supplying liquid from the reservoir 114 to the heating device 124 (e.g., the flow control system 118 may not include the pump 120 and/or the holding tank 122 in some contemplated embodiments, or the flow control system 118 may have a different network of conduits in other embodiments).

As shown in FIGS. 4 and 5, the heating device 124 includes at least one thin-film heating element, namely a first heating element 136 and a second heating element 138 in the illustrated embodiment. Without departing from the scope of this invention, the heating device 124 may be configured with any suitable number of thin-film heating elements (e.g., the heating device 124 may have only one heating element in some embodiments, or the heating device 124 may have more than two heating elements in other embodiments).

Referring now to FIGS. 7 and 8, each of the heating elements 136, 138 is tubular and has a first end 140, a second end 142, and a multi-layer body 144 extending from the first end 140 to the second end 142. The body 144 has a radially inner layer in the form of a substrate 146, and a radially outer layer in the form of an electrically conductive material 148 deposited on the substrate 146. As used herein, each heating element 136, 138 of the heating device 124 is said to be a “thin-film” heating element in the sense that the substrate 146 and the electrically conductive material 148 have a collective thickness that is only marginally greater than the thickness of the substrate 146 itself (i.e., the material 148 forms a thin film on the substrate 146).

In the illustrated embodiment, the first heating element 136 and the second heating element 138 are substantially identical (i.e., are made in the same manner using the same materials so as to have the same overall construction within accepted manufacturing tolerances). For instance, the substrate 146 of the heating elements 136, 138 may be a glass substrate (e.g., a borosilicate substrate, a quartz substrate, etc.), and the electrically conductive material 148 of the heating elements 136, 138 may be a metal oxide material (e.g., a tin oxide material). Hence, while only the first heating element 136 is shown in FIGS. 7 and 8, it is understood that the second heating element 138 is configured to be substantially identical.

In other embodiments, the heating elements 136, 138 may not be substantially identical (e.g., the first heating element 136 may have its substrate 146 made of a first composition, and its electrically conductive material 148 made of a second composition; whereas the second heating element 138 may have its substrate 146 made of a third composition that is different than the first composition, and its electrically conductive material 148 made from a fourth composition that is different than the second composition). Alternatively, each heating element 136, 138 of the heating device 124 may have its substrate 146 and its electrically conductive material 148 made from any suitable composition(s) that facilitate enabling the heating element(s) 136, 138 to function as described herein.

In the illustrated embodiment, the substrate 146 forms at least a segment of an interior surface 150 of the body 144, and the interior surface 150 defines a heating conduit 152 which extends through the body 144 from the first end 140 to the second end 142. In an alternative embodiment, an additional layer of the body 144 (e.g., a coating) may be disposed on a radially inner side of the substrate 146 such that the additional layer forms some or all of the interior surface 150.

The electrically conductive material 148, on the other hand, forms at least a segment of an exterior surface 154 of the body 144. For example, in the illustrated embodiment, the electrically conductive material 148 completely covers the radially outer side of the substrate 146, in the sense that the material 148 wraps completely around the substrate 146 from near the first end 140 to near the second end 142. In another contemplated embodiment, the material 148 may not completely cover the radially outer side of the substrate 146 but, rather, may instead be deposited on the substrate 146 in any suitable pattern (e.g., the material 148 may be deposited in a pattern of circumferentially spaced-apart lines, or a grid-like formation, that extends from near the first end 140 to near the second end 142).

Referring back to FIGS. 4 and 5, the body 144 (e.g., the substrate 146 and the electrically conductive material 148) are substantially transparent in the illustrated embodiment, thereby enabling liquid within the heating conduit 152 to be viewed from outside of the housing 102 through the second windows 112. In this manner, the illustrated coffeemaker 100 has a light source (e.g., at least one light emitting diode (LED) 156) for emitting light (e.g., a colored light such as red light, green light, blue light, etc.) through the heating conduit 152 to illuminate the liquid disposed within the heating conduit 152. This enhances the overall aesthetic appeal of the coffeemaker 100 during operation (e.g., the LEDs 156 facilitate illuminating bubbles in the liquid when the heating elements 136, 138 heat the liquid and as the bubbles rise through the heating conduit 152). While the illustrated LEDs 156 are disposed near the first ends 140 of the heating elements 136, 138 as set forth in more detail below, the LEDs 156 may be disposed at any suitable location(s) in other embodiments. Alternatively, the body 144 (e.g., the substrate 146 and/or the electrically conductive material 148) may be opaque (and the LEDs 156 therefore absent from the coffeemaker construction) without departing from the scope of this invention.

In the illustrated embodiment, the heating elements 136, 138 are oriented substantially parallel to one another and are held in spaced-apart relation via a grommet (or spacer) 158, and the grommet 158 engages a bracket 161 of the housing 102 to facilitate stabilizing the heating elements 136, 138 within the housing 102. Moreover, each of the heating elements 136, 138 is attached at its first end 140 to a one-way (or check) valve 162 via a first coupling 164 such that the heating conduit 152 is in flow communication with the downstream conduit 130 across the one-way valve 162. Each of the heating elements 136, 138 is also attached at its second end 142 to the showerhead 116 via a second coupling 166 such that the heating conduit 152 is in flow communication with the showerhead 116.

In the illustrated embodiment, the couplings 164, 166 are fabricated from a material that facilitates electrically and thermally isolating the heating elements 136, 138 from the one-way valve 162 and the showerhead 116, respectively (e.g., the couplings 164, 166 may be fabricated from a plastic or rubber material). Moreover, the one-way valve 162 is substantially transparent in the illustrated embodiment, and the LEDs 156 are mounted beneath the one-way valve 162 on a ledge 160 of the housing 102 to emit light through the one-way valve 162 into the heating conduit 152.

The illustrated heating device 124 further includes a first terminal 168 and a second terminal 170 attached to each of the heating elements 136, 138. The first terminal 168 is ring-shaped and wraps around the body 144 near the first end 140 in electrical contact with the material 148. Similarly, the second terminal 170 is ring-shaped and wraps around the body 144 near the second end 142 in electrical contact with the material 148. In alternative embodiments, the terminals 168, 170 may have any suitable shape and may be electrically connected to the material 148 of the body 144 in any suitable manner that facilitates enabling the heating elements 136, 138 to function as described herein.

Referring now to FIGS. 5 and 6, the first terminals 168 are electrically connected to one another via a first bus bar 172 to form a first terminal unit (indicated generally by reference numeral 174), thereby enabling electrical current to flow from one of the first terminals 168 to the other of the first terminals 168 across the first bus bar 172. Similarly, the second terminals 170 are electrically connected to one another via a second bus bar 176 to form a second terminal unit (indicated generally by reference numeral 178), thereby enabling electrical current to flow from one of the second terminals 170 to the other of the second terminals 170 across the second bus bar 176. Because the first terminal unit 174 and the second terminal unit 178 are substantially identical in the illustrated embodiment, only the first terminal unit 174 is represented in FIG. 6.

In some contemplated embodiments the first terminals 168 may not be electrically connected to one another via the first bus bar 172, and the second terminals 170 may not be electrically connected to one another via the second bus bar 176. Moreover, in other contemplated embodiments, the terminal units 174, 178 may be configured to suit any number of heating elements (e.g., the first terminal unit 174 may have four first terminals 168 electrically connected together by the first bus bar 172 if the heating device 124 has four heating elements). Alternatively, the material 148 may not extend from near the first end 140 to near the second end 142, but may instead be limited to a central region of the body 144 such that the terminals 168, 170 are electrically connected to the body 144 at the central region of the body 144 rather than near the ends 140, 142 of the body 144.

In the illustrated embodiment, each of the terminals 168, 170 and each of the bus bars 172, 176 have a wire port 180 that facilitates electrically connecting wires to the terminal units 174, 178. In this manner, by virtue of the terminals 168, 170 being in electrical contact with the material 148, the material 148 of each heating element 136, 138 is electrically connectable to a suitable power supply (e.g., a battery stowed within the housing 102 or a remote power supply) via the wires.

When electrical current is thereby supplied to each heating element 136, 138, the electrical current flows from the first terminal 168 to the second terminal 170 across the electrically conductive material 148. Because the material 148 naturally resists the flow of current therethrough, the material 148 heats up as a result. Such heating of the material 148 causes the substrate 146 to be heated by virtue of the substrate 146 being in conductive heat transfer with the material 148. This facilitates heating any fluid (e.g., water) disposed within the heating conduits 152.

In the illustrated embodiment, the electrical current supplied to the electrically conductive material 148 is regulated by a control unit 182 (shown in FIG. 3) disposed within the housing 102. More specifically, the control unit 182 modulates the flow of electrical current from the power supply through the electrically conductive material 148 during operation of the coffeemaker 100 to control the temperature of the substrate 146 and, hence, the temperature of the liquid flowing through the heating conduits 152.

Optionally, the control unit 182 may be operatively connected to a suitable temperature sensor (e.g., a bimetallic temperature switch 184, shown in FIGS. 3 and 4) for regulating a temperature of the heating elements 136, 138 (such as, for example, to facilitate preventing the heating elements 136, 138 from overheating if little or no water is inside heating conduits 152). The control unit 182 suitably includes a microcontroller and a memory for storing instructions to be executed by the microcontroller when modulating electrical current to the heating element(s) 136, 138 in response to a selection by the user.

In one example of operating the coffeemaker 100 to brew coffee, the user presses a button on an interface of the coffeemaker 100 (or a remote interface, such as a wireless device). The control unit 182 responds by supplying electrical current to the heating elements 136, 138, and the electrical current flows across the material 148 of each heating element 136, 138 via it associated terminals 168, 170. This raises the temperature of the substrate 136 and, hence, the temperature inside the heating conduit 152.

Before, during, or after supplying current to the heating elements 136, 138, the control unit 182 also operates the pump 120 to supply water from the reservoir 114 to the heating elements 136, 138 via the conduits 126, 128, 130, and the water enters the heating conduits 152 via the one-way valve 162. As the temperature of the water within the heating conduits 152 is raised and the pressure inside the heating conduits 152 increases, the water evacuates the heating conduits 152 into the filter basket 104 via the showerhead 116. Once the heating conduits 152 have been at least partially evacuated, additional water is permitted to flow into the heating conduits 152 via the one-way valve 162.

As shown in FIG. 3, because the illustrated holding tank 122 is elevated in relation to the max-fill marker 134 of the reservoir 114 (and in relation to the one-way valve 162), the holding tank 122 gravitationally pressurizing the water flowing from the reservoir 114 to the heating device 124 to facilitate ensuring that water is supplied to the heating elements 136, 138 despite whether the level of water within the reservoir 114 is low.

Optionally, in some contemplated embodiments (e.g., embodiments that do not include the pump 120), a flow control valve 186 may be disposed between the heating element(s) 136, 138 and the showerhead 116, as shown schematically in FIG. 9. In this manner, the flow control valve 186 may be configured to prevent the heated water from prematurely evacuating the heating conduit(s) 152 until a predetermined water temperature is reached. For example, the control unit 182 may be configured to operate the flow control valve 186 to inhibit the heated water from prematurely evacuating the heating conduit(s) 152 until a predetermined water temperature is reached. Thus, in some embodiments, the water may be heated to a desired temperature, which is selectable from a plurality of predetermined temperatures.

Referring now to FIGS. 10 and 11, rather than having heating device 124 and showerhead 116, the fluid heating appliance 100 may instead have a heating device (indicated generally by reference numeral 188) and associated showerhead 190. In the illustrated embodiment, the heating device 188 includes a frame 192 (e.g., a silicone frame) and a pair of thin-film heating elements 194 mounted in spaced relation on the frame 192 such that the frame 192 substantially seals around the bottom and sides of each heating element 194.

The heating elements 194 are in the form of substantially rectangular panes (e.g., are substantially planar objects), such that a heating conduit 196 having an open-top, generally cuboidal volumetric shape is defined between the heating elements 194. A one-way valve 198 is connected to the frame 192 in flow communication with the bottom of the heating conduit 196, and the showerhead 190 is connected to the frame 192 in flow communication with the open top of the heating conduit 196. The one-way valve 198 is also configured for connection to the downstream conduit 130 to place the downstream conduit 130 in flow communication with the heating conduit 196 across the one-way valve 198. Optionally, in an alternative embodiment, the heating device 188 may have only one heating element 194, with an additional sidewall of the frame 192 in place of the other heating element 194, for example.

Each of the heating elements 194 is constructed much like the heating elements 136, 138 above, in the sense that each heating element 194 has a substrate, an electrically conductive material deposited on the substrate, and a pair of bus bars 199 suitably attached to, or deposited on, the substrate. When electrical current is supplied to the bus bars 199 by the control unit 182, the current flows across the electrically conductive material and heats the substrate to, in turn, heat the conduit 196. Water in the conduit 196 is heated as a result, and the heated water evacuates the conduit 196 toward the open top of the conduit 196 and spills over into the showerhead 190 for delivery to the filter basket 104.

Moreover, the heating device 188 may be viewable through the window(s) 112 of the housing 102, and may be illuminated by the light source (e.g., the LEDs 156), in a manner similar to that of heating device 124 set forth above. Suitably, the control unit 182 operates the one-way valve 198 and the heating element(s) 194 in a manner similar to that set forth above for one-way valve 162 and heating elements 136, 138 (e.g., to induce water flow into conduit 196, regulate the temperature within conduit 196, etc.).

In accordance with the embodiments set forth herein, the coffeemaker 100 having the heating device 124 and/or 188 heats water more rapidly and to a more precise temperature than at least some conventional calrod-type heating devices, thereby improving the overall operating efficiency of the coffeemaker 100.

When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A coffeemaker comprising: a reservoir; anda flow control system for regulating a flow of water from the reservoir, wherein the flow control system includes a thin-film heating element that defines at least a portion of a heating conduit in which water is heated.

2. The coffeemaker of claim 1, wherein the heating element has a glass substrate and a metal oxide material deposited on the glass substrate.

3. The coffeemaker of claim 2, wherein the heating element is substantially transparent.

4. The coffeemaker of claim 3, further comprising a housing in which the heating element is disposed, wherein the housing has a window through which the heating element is visible.

5. The coffeemaker of claim 4, further comprising a light source for illuminating water within the heating conduit.

6. The coffeemaker of claim 5, wherein the light source emits a colored light.

7. The coffeemaker of claim 5, wherein the heating element has an end and wherein the flow control system further comprises a one-way valve connected to the heating element at the end, the light source being mounted adjacent the one-way valve for emitting light into heating conduit through the one-way valve.

8. The coffeemaker of claim 1, wherein the heating element has an end and wherein the flow control system further comprises a coupling fitted on the end to facilitate electrically and thermally isolating the end of the heating element.

9. The coffeemaker of claim 1, further comprising a pair of the heating elements.

10. The coffeemaker of claim 9, wherein the heating elements are spaced apart from one another and are oriented substantially parallel with one another.

11. The coffeemaker of claim 1, wherein the heating element is substantially planar.

12. The coffeemaker of claim 1, wherein the heating element is tubular and wherein the coffeemaker further comprises a first ring-shaped terminal and a second ring-shaped terminal that wrap around the heating element.

13. The coffeemaker of claim 12, wherein the heating element has a first end and a second end, the first ring-shaped terminal wrapping around the heating element near the first end, and the second ring-shaped terminal wrapping around the heating element near the second end.

14. The coffeemaker of claim 12, further comprising: a pair of the heating elements spaced apart from one another and oriented substantially parallel with one another;a first terminal unit comprising a first bus bar and a pair of the first ring-shaped terminals connected together by the first bus bar; anda second terminal unit comprising a second bus bar and a pair of the second ring-shaped terminals connected together by the second bus bar,wherein each of the first ring-shaped terminals wraps around one of the heating elements, and each of the second ring-shaped terminals wraps around one of the heating elements.

15. A coffeemaker comprising: a reservoir;a showerhead; anda flow control system for regulating a flow of water from the reservoir to the showerhead, wherein the flow control system includes: a thin-film heating element that defines a heating conduit in which water is heated;a check valve disposed between the reservoir and the heating element; anda flow control valve disposed between the heating element and the showerhead.

16. The coffeemaker of claim 15, wherein the flow control system does not include a pump.

17. The coffeemaker of claim 16, wherein the flow control system is configured to gravitationally pressurize the flow of water from the reservoir to the showerhead.

18. The coffeemaker of claim 17, wherein the flow control valve inhibits heated water from prematurely evacuating the heating conduit until the heated water reaches a temperature selected from a plurality of predetermined temperatures.

19. The coffeemaker of claim 15, wherein the heating element is tubular and comprises a glass substrate and a metal oxide material deposited on the substrate.

20. A terminal unit for a heating device having a pair of tubular, thin-film heating elements, said terminal unit comprising: a pair of ring-shaped terminals each sized to wrap around one of the heating elements; anda bus bar extending between the ring-shaped terminals to electrically connect the ring-shaped terminals to one another.