Patent Description:
Various types of coffee machine are known. One example is a so-called drip coffee machine in which a heating tube is used to boil and pump water to a delivery outlet, e.g. a delivery outlet in the form of a shower head or drip area, arranged above a receptacle containing coffee grounds. The heated water is distributed by the delivery outlet over the coffee grounds, and flows through the coffee grounds. Coffee oil, also called caffeol, is extracted during this coffee brewing process. The brewed coffee may then drip into a coffee pot arranged beneath the receptacle.

In conventional drip coffee machines, all of the water in a water reservoir upstream of the heating tube tends to be heated and delivered to the receptacle to drip through the coffee grounds unless the user manually cuts off the electrical power to the heating tube.

In such conventional drip coffee machines, the strength of the brewed coffee, which partly depends on the quantity of coffee grounds relative to the amount of heated water added thereto, is manually controlled by the user.

In high end coffee machines, a motorized pump and flow meter can be used to control the quantity of water that drips through the coffee grounds. However, such components add complexity and cost to the architecture of such high end coffee machines, and may also increase their size.

<CIT> discloses a continuous preparation method of boiling water based on gas-liquid two-phase detection which uses a two-phase detection sensor which can detect in real time the gas-liquid two-phase flow.

<CIT> discloses a control system for use with a beverage brewing apparatus wherein the controller uses the sensed temperature for controlling the brewing apparatus.

According to examples in accordance with an aspect of the invention, there is provided a coffee brewing apparatus comprising: a reservoir for holding water; a receptacle for containing coffee grounds; a delivery outlet at which water is supplied into the receptacle; a one-way valve; tubing for carrying water from the one-way valve to the delivery outlet, a heatable section of the tubing being configured such that water in the heatable section is heated to generate water vapor bubbles, and the delivery outlet being at an elevated position, in use, relative to the heatable section, wherein the one-way valve is arranged to permit water transport therethrough from the reservoir towards the heatable section but restrict transport of the heated water comprising said water vapor bubbles from the heatable section back towards the reservoir, the heated water comprising said water vapor bubbles being thereby caused to rise in the tubing from the heatable section to the delivery outlet; a sensor configured to sense bubbling in water in the tubing between the heatable section and the delivery outlet; and a controller configured to: determine, based on sensory data from the sensor, a start of bubbling in the tubing following initiation of power supply to heat the water in the heatable section; and control heated water delivery to the receptacle based on the determined start of bubbling.

The coffee brewing apparatus may operate to transport water to the receptacle in which coffee grounds are receivable due to the heating of the water in the heatable section of the tubing creating a mixture of heated water and water vapor bubbles.

This mixture may be less dense than the water supplied from the reservoir towards the heatable section of the tubing, such that the mixture may be more buoyant than the water being supplied towards the heatable section. This may result in the mixture being carried to up the tubing from the heatable section to the delivery outlet, since the one-way valve restricts, e.g. blocks, flow from the heatable section in the opposite direction towards the reservoir.

The present invention is based, at least in part, on the realization that a sensor configured to sense bubbling in water in the tubing between the heatable section and the delivery outlet can assist to facilitate control over how much heated water is carried to the receptacle, and accordingly the amount of brewed coffee produced, in a reliable, compact, and relatively low-cost manner. This is because the sensor can be used to determine when the bubbling in the water in the tubing begins, and correspondingly the point at which the heated water starts to be transported to the receptacle.

In view of heated water being transportable at a relatively constant flow rate, or at least at a predicable flow rate, the sensor's capability to determine when the bubbling in water begins means that the quantity of water transported to the receptacle is straightforwardly controllable, for example by controlling a duration of heating of the water from the sensed point at which the bubbling in water heated in the tubing starts to occur.

By the controller being configured to control heated water delivery to the receptacle based on the determined start of bubbling, the bubbling sensor-based control of the water transport to the delivery outlet may be automatic.

Initiation of power supply may, for example, refer to initial activation of a heating element when power is supplied thereto so that water is heated in the heatable section.

Such initial activation may be implemented by switching on the coffee brewing apparatus, e.g. via a power switch.

In some embodiments, the sensor comprises a pair of electrodes for contacting the water in the tubing. Such an electrical sensor may provide a convenient, compact, and relatively low-cost way of sensing bubbling in the water heated in the tubing.

In such embodiments, the sensor may be configured to provide a measure of a resistance or current between the pair of electrodes. The sensor providing such a measure of resistance or current between the pair of electrodes may reflect the change, in particular decrease, in electrical resistance of the water resulting from generation of the water vapor bubbles.

The heatable section of the tubing may have an inlet through which water to be heated is deliverable into the heatable section, and an outlet through which heated water exits the heatable section. In such embodiments, the sensor may be arranged to sense bubbling in water exiting the outlet of the heatable section.

Positioning the sensor in this manner, in other words at or proximal to the outlet of the heatable section, may enable reliable sensing of the point at which the heated water starts being transported to the receptacle. Installation of the sensor at such a position may also be relatively straightforward.

In some embodiments, the coffee brewing apparatus comprises a connector member configured to house at least part of the sensor, with the tubing comprising a further tubing section for carrying heated water from the heatable section towards the delivery outlet. In such embodiments, the connector member may connect the heatable section to the further tubing section.

Such a connector member may facilitate installation of the sensor, for example the pair of electrodes, at a position that permits reliable sensing of the point at which the heated water starts to be transported to the receptacle.

In some embodiments, the controller is configured to determine the start of bubbling based on an output of the sensor satisfying a given threshold.

For example a resistance or current threshold may be reached in the case of the electrical sensor. The given threshold may be indicative of the point at which bubbling in the heated water causes the heated water to be transported to the receptacle.

A timer may be included in the coffee brewing apparatus, for example as part of the controller. In such embodiments, the controller may control heated water delivery to the receptacle based on a duration timed by the timer that begins with the determined start of bubbling.

Such a duration, e.g. a pre-set duration, may enable an amount of brewed coffee to be reliably and straightforwardly controlled via the quantity of heated water delivered to the receptacle.

For example, the controller may be configured to control the heating of the water in the heatable section based on the duration timed by the timer that begins with the determined start of bubbling.

In some embodiments, the controller is configured to reduce or stop the power supply that heats the water in the heatable section following completion of the duration. Thus, heated water transport to the receptacle may be ceased.

In some embodiments, the coffee brewing apparatus comprises a user interface configured to enable user input of a desired quantity of brewed coffee to be produced, with the controller being configured to control heated water delivery to the receptacle based on the determined start of bubbling and the user input.

For example, the user input may be used to set the duration timed by the timer that begins with the determined start of bubbling.

In this manner, the quantity of brewed coffee produced by the coffee brewing apparatus need not depend simply on a volume of water in the reservoir, nor on power supply to the heating element being manually terminated by the user.

According to another aspect there is provided a method of operating a coffee brewing apparatus having: a reservoir for holding water; a receptacle for containing coffee grounds; a delivery outlet at which water is supplied into the receptacle; a one-way valve; tubing for carrying water from the one-way valve to the delivery outlet, a heatable section of the tubing being configured such that water in the heatable section is heated to generate water vapor bubbles, and the delivery outlet being at an elevated position, in use, relative to the heatable section, wherein the one-way valve is arranged to permit water transport therethrough from the reservoir towards the heatable section but restrict transport of the heated water comprising said water vapor bubbles from the heatable section back towards the reservoir, the heated water comprising said water vapor bubbles being thereby caused to rise in the tubing from the heatable section to the delivery outlet; and a sensor configured to sense bubbling in water in the tubing between the heatable section and the delivery outlet, the method comprising: determining, based on sensory data received from the sensor, a start of bubbling in the tubing following initiation of power supply to heat the water in the heatable section; and controlling heated water delivery to the receptacle based on the determined start of bubbling.

In some embodiments, and as described above in relation to the coffee brewing apparatus, the sensor comprises a pair of electrodes for contacting the water in the tubing. In such embodiments, the sensory data may comprise a measure of resistance or current between the pair of electrodes.

In some embodiments, the controlling heated water delivery to the receptacle comprises controlling heating of the water in the heatable section.

Alternatively or additionally, the controlling the heated water delivery to the receptacle may be based on a duration that begins with the determined start of bubbling.

In such embodiments, the controlling the heated water delivery to the receptacle may comprise reducing or stopping the power supply that heats the water in the heatable section following completion of the duration.

In some embodiments, the method comprises receiving a user input of a desired quantity of brewed coffee to be produced, with the controlling the heated water delivery to the receptacle being based on the determined start of bubbling and the user input.

For example, the user input, e.g. via a user interface included in the coffee brewing apparatus, may be used to set the duration timed by the timer that begins with the determined start of bubbling.

In this manner, the quantity of brewed coffee produced need not depend simply on a volume of water in the reservoir, nor on power supply to the heating element being manually terminated by the user.

According to a further aspect there is provided a computer program comprising computer program code which, when executed on a computing device having a processing system, causes the processing system to perform all of the steps of the method according to any of the embodiments described herein.

One or more non-transitory computer readable media may be provided, which non-transitory computer readable media have a computer program stored thereon, with the computer program comprises computer program code which is configured, when the computer program is run on the one or more processors, to cause the processing system to implement the method according to any of the embodiments described herein.

The processing system may be, for example, included in the controller of the coffee brewing apparatus described herein.

More generally, embodiments described herein in relation to the coffee brewing apparatus may be applicable to the method and computer program, and embodiments described herein in relation to the method and computer program may be applicable to the coffee brewing apparatus.

Provided is a coffee brewing apparatus having tubing that extends from a one-way valve to a delivery outlet. Water is supplied via the delivery outlet into a receptacle for containing coffee grounds. Heating of water in a heatable section of the tubing generates water vapor bubbles. The one-way valve is arranged to restrict backflow, in a direction away from the delivery outlet, so that the heated water comprising water vapor bubbles is transported in the tubing from the heatable section to the delivery outlet. A sensor senses bubbling in water in the tubing between the heatable section and the delivery outlet. This sensor has been found to facilitate control over how much heated water is carried to the receptacle, and accordingly the amount of brewed coffee produced, in a reliable, compact, and relatively low-cost manner. Further provided is a method of operating such a coffee brewing apparatus, and a related computer program.

<FIG> schematically depicts a coffee brewing apparatus <NUM> according to an example. The coffee brewing apparatus <NUM> comprises a reservoir <NUM> for holding water prior to the water being heated. The heated water is ultimately delivered to coffee grounds contained in a receptacle <NUM>.

A coffee filter (not visible) may be inserted into the receptacle <NUM>, and coffee grounds may be placed on the coffee filter. Such a coffee filter may assist to retain the coffee grounds in the receptacle <NUM>, whilst permitting brewed coffee to pass through the coffee filter.

In some embodiments, such as that shown in <FIG>, the coffee brewing apparatus <NUM> comprises a brewed coffee container <NUM>, e.g. a coffee pot, that receives brewed coffee from the receptacle <NUM>.

For example, the brewed coffee container <NUM> receives brewed coffee that has passed through the coffee filter received in the receptacle <NUM>.

Whilst not visible in <FIG>, one or more channels for the brewed coffee may extend through a base of the receptacle <NUM>. The brewed coffee may pass from the receptacle <NUM> via the one or more channels to the brewed coffee container <NUM>.

The reservoir <NUM> may be delimited by one or more reservoir walls. Such reservoir wall(s) may be formed of any suitable material capable of retaining water within the reservoir <NUM>, such as a plastic material or glass.

In some embodiments, such as that shown in <FIG>, the reservoir wall(s) is or are made, at least in part, of an optically transmissive material, such as an optically transmissive plastic material or glass, that allows a level of water in the reservoir <NUM> to be identified.

The optically transmissive reservoir wall(s) may be provided with volume markings <NUM>. Such volume markings <NUM> are conventionally used as a guide to assist the user in determining how much brewed coffee is produced. In conventional drip coffee machines, all of the water contained in such a reservoir <NUM> may be delivered to the brewed coffee container <NUM>, unless the user manually cuts off the electrical power supply so as to stop heating of the water while there is still water remaining in the reservoir <NUM>. As will be explained in more detail herein below, the quantity of brewed coffee produced by the coffee brewing apparatus <NUM> according to the present disclosure need not be determined by the volume of water in the reservoir <NUM>.

The delivery of the heated water is implemented via a one-way valve <NUM> and tubing <NUM> that extends from the one-way valve <NUM> to a delivery outlet <NUM>. The water is heated in a heatable section <NUM> of the tubing <NUM>, and the heated water is supplied into the receptacle <NUM> via the delivery outlet <NUM>.

The delivery outlet <NUM> may be defined by apertures of a perforate plate. Such apertures may distribute the heated water to various regions of coffee grounds contained in the receptacle <NUM>.

It is noted that the perforate plate may be regarded as being included in, or defining, a shower head or drip area from which the heated water is supplied to the coffee grounds contained in the receptacle <NUM>. The heated water may drip from the delivery outlet <NUM> relatively evenly onto the coffee grounds.

More generally, the delivery outlet <NUM> may be arranged above the receptacle <NUM> when an in-use orientation of the coffee brewing apparatus <NUM> is adopted, such that the heated water falls from the delivery outlet <NUM> into the receptacle <NUM>, with the brewed coffee dripping from the receptacle <NUM> down into the brewed coffee container <NUM> beneath the receptacle <NUM>.

The coffee brewing apparatus <NUM> can thus be regarded as comprising a so-called "drip coffee machine".

The heated water may flow through the ground coffee beans, picking up their oil essence (coffee oil, released during the roasting process, which is called caffeol) on the way down into the brewed coffee container <NUM>.

The receptacle <NUM> may be delimited by wall(s) formed of any suitable material capable of withstanding the temperature of the heated water delivered into the receptacle <NUM> to brew coffee. In some embodiments, the wall(s) delimiting the receptacle <NUM> are formed from a plastic material.

The receptacle <NUM> may be funnel-shaped, such that the receptacle <NUM> tapers in the direction of the brewed coffee container <NUM>, as shown in <FIG>.

The receptacle <NUM> may be detachable from the rest of the coffee brewing apparatus <NUM> so as to facilitate dispensing of coffee grounds into, and removal of used coffee grounds from, the receptacle <NUM>, and, for example, replacement of a coffee filter. To that end, a handle <NUM> may be provided for assisting the user to detach the receptacle <NUM>.

The water in the reservoir <NUM> may flow through the one-way valve <NUM> into the tubing <NUM> in the direction of the heatable section <NUM> by gravity.

The water is heated in the heatable section <NUM> of the tubing <NUM> to generate water vapor bubbles. In other words, the water in the heatable section <NUM> is heated up and eventually boils (at <NUM> atm pressure, sealevel, <NUM>). This boiling creates bubbles, and thus a pressure to push water flow.

The one-way valve <NUM> is arranged to permit water transport therethrough from the reservoir <NUM> towards the heatable section <NUM> but restrict transport of the heated water comprising the water vapor bubbles from the heatable section <NUM> back towards the reservoir <NUM>. In other words, passage back to the reservoir <NUM> is blocked by the one-way valve <NUM>, so that the heated water flows to the delivery outlet <NUM>. It is noted that if there were no one-way valve <NUM>, then the boiling water could flow back into the reservoir <NUM>.

Due to the mixture of heated water and water vapor bubbles being less dense than the water supplied from the reservoir <NUM>, the mixture may be more buoyant than the water being supplied from the reservoir <NUM> towards the heatable section <NUM>. This may result in the mixture being carried from the heatable section <NUM>, via a further tubing section <NUM> of the tubing <NUM>, to the delivery outlet <NUM>. This is due to the one-way valve <NUM> restricting, e.g. blocking, flow from the heatable section <NUM> in the opposite direction towards the reservoir <NUM>.

With continued boiling of the water, the bubbles may rise in the further tubing section <NUM>, e.g. a vertically extending further tubing section <NUM>.

The internal diameter of the further tubing section <NUM> may be sufficiently small relative to the size of the bubbles that a column of water can ride upwards to the delivery outlet <NUM> on top of the bubbles.

Thus, this design obviates the requirement for a motorized pump to transport the heated water to the receptacle <NUM>. The design of the coffee brewing apparatus <NUM> can therefore be relatively simple and low-cost.

The heatable section <NUM> of the tubing <NUM> can be heated in any suitable manner. In some embodiments, such as that shown in <FIG>, a heating element <NUM> is arranged to heat the heatable section <NUM> of the tubing <NUM>.

The heating element <NUM> is, for example, a resistive heating element <NUM>.

In some embodiments, the heatable section <NUM> comprises, for example is defined by, a heating tube that includes the heating element <NUM> as an integral component.

As an example of such a heating tube, a heatable section <NUM> formed from aluminum tubing is attached, e.g. adhered to, a resistive heating element <NUM>. An illustrative example of such a heating tube will be described below with reference to <FIG> to 5C.

More generally, the heatable section <NUM> of the tubing <NUM> may be formed from any suitable material, such as a metal or metal alloy. By forming the heatable section <NUM> from such a metal or metal alloy, heat may be efficiently transferred from the heating element <NUM> to the water inside the heatable section <NUM>.

For example, the heatable section <NUM> may be formed from aluminium.

It is noted that sections of the tubing <NUM> upstream and downstream of the heatable section <NUM>, such as the further tubing section <NUM>, can be formed of any suitable material, such as a plastic or elastomeric material.

For example, the sections of the tubing <NUM> upstream and/or downstream of the heatable section <NUM>, such as the further tubing section <NUM>, can be formed of silicone.

As shown in <FIG>, the delivery outlet <NUM> is at an elevated position relative to the heatable section <NUM> of the tubing <NUM> when the in-use orientation of the coffee brewing apparatus <NUM> is adopted. The further tubing section <NUM> of the tubing <NUM> may thus extend upwardly from the heatable section <NUM> to the delivery outlet <NUM> at the elevated position. In this case, the heated water comprising the water vapor bubbles rises in the further tubing section <NUM> from the heatable section <NUM> to the delivery outlet <NUM>.

In at least some embodiments, such as that shown in <FIG>, the receptacle <NUM> is arranged above the brewed coffee container <NUM>, with the heatable section <NUM> of the tubing <NUM> being arranged proximal, e.g. underneath, the brewed coffee container <NUM>.

Such positioning of the heatable section <NUM> may enable the heatable section <NUM> to, in addition to heating the water used for brewing the coffee, heat the brewed coffee container <NUM>, to keep the brewed coffee warm. By the heatable section <NUM> fulfilling both functions, there may be no need for the coffee brewing apparatus <NUM> to include an additional heating element dedicated to heating the brewed coffee container <NUM>. This assists to make the design of the coffee brewing apparatus <NUM> simpler and lower cost.

In some embodiments, such as that shown in <FIG>, the coffee brewing apparatus <NUM> includes a heatable plate <NUM> arranged to heat the brewed coffee container <NUM> that receives brewed coffee from the receptacle <NUM>. As shown in <FIG>, the heatable plate <NUM> may be arranged to support, and heat, the brewed coffee container <NUM> when the brewed coffee container <NUM> is placed on the heatable plate <NUM>.

The heatable plate <NUM> and the heatable section <NUM> of the tubing <NUM> may be heated by a common heating element <NUM>, for example by the heating element <NUM> that is an integral component of the heating tube.

Power may be supplied from a mains source of power to the heating element <NUM>, for example from the mains source of power to the heating element <NUM> included as an integral component of the heating tube, via a power cable <NUM>.

The coffee brewing apparatus <NUM> may include an electrical fuse <NUM> connected between the power cable <NUM> and the heating element <NUM>.

The brewed coffee container <NUM> may be delimited by wall(s) made of any suitable material, such as a metallic material and/or glass, such as a borosilicate glass, e.g. Pyrex®. Such materials may assist in transferring heat from the heating element <NUM>, e.g. via the heatable plate <NUM>, to the brewed coffee in the brewed coffee container <NUM>.

In some embodiments, the wall(s) delimiting the brewed coffee container <NUM> may be vacuum insulated. This may assist the brewed coffee to be kept warm with less, or in some cases without, heating via the heatable plate <NUM> being required.

The brewed coffee container <NUM> may be detachable from the rest of the coffee brewing apparatus <NUM> so as to enable a user to pour brewed coffee therefrom into a cup or other vessel. To that end, a handle <NUM> may be provided for assisting the user to detach the brewed coffee container <NUM> and pour the brewed coffee therefrom.

In some embodiments, the heating element <NUM> may be controlled to heat the brewed coffee container <NUM>, e.g. to keep the brewed coffee therein warm, for a predetermined time period prior to the power supply to the heating element <NUM> being stopped automatically.

The predetermined time period may be, for example <NUM> minutes to <NUM> hour, for example about <NUM> minutes.

As shown in <FIG>, the coffee brewing apparatus <NUM> comprises a sensor <NUM> configured to sense bubbling in water in the tubing <NUM> between the heatable section <NUM> and the delivery outlet <NUM>. This can assist to facilitate control over how much heated water is carried to the receptacle <NUM>, and accordingly the amount of brewed coffee produced, in a reliable, compact, and relatively low-cost manner.

To this end, a controller (not visible) can be configured to determine, based on sensory data from the sensor <NUM>, a start of bubbling in the tubing <NUM> between the heatable section <NUM> and the delivery outlet <NUM> following initiation of power supply to heat the water in the heatable section <NUM>. The controller can further control heated water delivery to the receptacle <NUM> based on the determined start of bubbling.

The sensor <NUM> in combination with the controller can be used to determine when the bubbling in the water heated in the tubing <NUM> begins, and correspondingly the point at which the heated water starts to be transported to the receptacle <NUM>.

Initiation of power supply may, for example, refer to initial activation of the heating element <NUM> when power is supplied thereto so that the heatable section <NUM> heats water therein.

Such initial activation may be implemented by switching on the coffee brewing apparatus <NUM>, e.g. by the user actuating a power switch.

In view of heated water being transportable at a relatively constant flow rate, or at least at a predicable flow rate, the capability of the sensor <NUM> in combination with the controller to determine when the bubbling in water begins means that the quantity of water transported to the receptacle <NUM> can be reliably and straightforwardly controlled.

<FIG> provides graphs of water volume delivered via the tubing <NUM> vs flow time from a start of bubble build-up in a coffee brewing apparatus <NUM> according to an example. The graphs plot measurement data from a coffee brewing apparatus <NUM> having a resistive heating element <NUM> included in an aluminium heating tube having an internal diameter of <NUM>. The heating element is powered by a <NUM> V <NUM>, <NUM> W AC power supply. It is noted, still with reference to <FIG>, that conventional drip coffee machines can provide <NUM> to <NUM> cups of brewed coffee, in other words <NUM> to <NUM>, with the average flow rate being about <NUM>/second.

The graphs provided in <FIG> demonstrate that the quantity of water transported to the receptacle <NUM> is straightforwardly and reliably controllable via a time duration starting from when the bubbling in the water heated in the tubing <NUM> begins.

A timer may be included in the coffee brewing apparatus <NUM>, for example as part of the controller. In such embodiments, the controller may control heated water delivery to the receptacle <NUM> based on a duration timed by the timer that begins with the determined start of bubbling in the tubing <NUM>.

Such a duration, e.g. a pre-set duration, may enable an amount of brewed coffee to be reliably and straightforwardly controlled via the quantity of heated water delivered to the receptacle <NUM>.

For example, the controller may be configured to control the heating of the water in the heatable section <NUM> based on the duration timed by the timer that begins with the determined start of bubbling.

In some embodiments, the controller is configured to reduce or stop the power supply, e.g. to the heating element <NUM>, that heats the water in the heatable section <NUM> following completion of the duration.

In some embodiments, the coffee brewing apparatus <NUM> comprises a user interface, such as one or more buttons, a dial, and/or a touchscreen, configured to enable user input of a desired quantity of brewed coffee to be produced, with the controller being configured to control heated water delivery to the receptacle <NUM> based on the determined start of bubbling and the user input.

For example, the user input may be used to set the duration timed by the timer that begins with the determined start of bubbling. Thus, a longer duration may be timed by the timer when the user desires to produce more, e.g. a larger number of cups of, brewed coffee.

In this manner, the quantity of brewed coffee produced by the coffee brewing apparatus <NUM> need not depend simply on a volume of water in the reservoir <NUM>, nor on power supply to the heating element <NUM> being manually terminated by the user.

More generally, the controller can have any suitable design and be arranged in any suitable manner in order to implement the functions described herein.

In at least some embodiments, the controller may comprise a microcontroller unit provided in a coffee machine that is included in the coffee brewing apparatus <NUM>.

Such a microcontroller unit can, for example, be mounted on a printed circuit board assembly included in the coffee machine.

Any suitable type of sensor <NUM> can be employed to sense bubbling in the tubing <NUM> between the heatable section <NUM> and the delivery outlet <NUM>.

In some embodiments, such as that shown in <FIG> and <FIG>, the sensor <NUM> comprises a pair of electrodes 122A, 122B for contacting the water in the tubing <NUM>. Such an electrical sensor <NUM> may provide a convenient, compact, and relatively low-cost way of sensing bubbling in the water heated in the tubing <NUM>.

In such embodiments, the sensor <NUM> may be configured to provide a measure of a resistance or current between the pair of electrodes 122A, 122B. The sensor <NUM> providing such a measure of resistance or current between the pair of electrodes 122A, 122B may reflect the change, in particular decrease, in electrical resistance of the water resulting from generation of the water vapor bubbles.

When an electrical resistance at the outlet of the heatable section <NUM> was measured, using a <NUM> V multimeter, for the prototype coffee brewing apparatus <NUM> used to gather the measurement data plotted in <FIG>, a resistance between the electrodes 122A, 122B was about <NUM> MΩ prior to the water being heated. When the water was heated up to boiling and the heated water started to flow to the delivery outlet <NUM>, the resistance decreased to about <NUM> MΩ.

With reference to <FIG>, the sensor <NUM> may include an AC power supply <NUM> connected to the pair of electrodes 122A, 122B. The voltage across the electrodes 122A, 122B provided by the AC power supply <NUM> may be a low voltage for safety reasons. The current is schematically represented in <FIG> by the double-headed arrow <NUM>. In this non-limiting example, an ammeter <NUM> is included in the sensor <NUM>. The circuit is completed by positive ions <NUM> and negative ions <NUM> inherently present in the water between the electrodes 122A, 122B. The electrodes 122A, 122B are spaced apart from each other by a distance <NUM>.

In some embodiments, the controller is configured to determine the start of bubbling based on an output of the sensor <NUM> satisfying a given threshold.

For example, a resistance or current threshold may be reached in the case of the electrical sensor <NUM>. The given threshold may be indicative of the point at which bubbling in the heated water causes the heated water to be transported to the receptacle <NUM>.

It is noted that alternative sensor types can be contemplated for sensing bubbling in the heated water between the heatable section <NUM> and the delivery outlet <NUM>, such as a vibration sensor <NUM>, e.g. a micro-electromechanical systems (MEMS) vibration sensor <NUM>. Such a vibration sensor <NUM> may sense vibrations caused by bubbling of the heated water.

In some embodiments, such as that shown in <FIG> and <FIG>, the heatable section <NUM> has an inlet <NUM> through which water to be heated is deliverable into the heatable section <NUM>, and an outlet <NUM> through which heated water exits the heatable section <NUM>, with the sensor <NUM> being arranged to sense bubbling in water exiting the outlet <NUM> of the heatable section <NUM>.

Positioning the sensor <NUM> in this manner, in other words at or proximal to the outlet <NUM> of the heatable section <NUM>, may enable reliable sensing of the point at which the heated water starts being transported to the receptacle <NUM>. Installation of the sensor <NUM> at such a position may also be relatively straightforward.

Arranging the sensor <NUM> to sense bubbling in water exiting the outlet <NUM> of the heatable section <NUM> can be implemented in any suitable manner.

In some embodiments, and referring to <FIG>, <FIG> and <FIG>, a connector member <NUM> is configured to house at least part of the sensor <NUM>, and the connector member <NUM> may connect the heatable section <NUM> to the further tubing section <NUM>. Thus, the connector member <NUM> can be regarded as an adaptor whose function is partly to enable the heatable section <NUM> to be fitted to the further tubing section <NUM>.

Such a connector member <NUM> may facilitate installation of the sensor <NUM>, for example the pair of electrodes 122A, 122B, at a position that permits reliable sensing of the point at which the heated water starts to be transported to the receptacle <NUM>.

As shown in <FIG>, a seal <NUM> may be interposed between the connector member <NUM> and an outlet end of the heatable section <NUM>. The seal <NUM> may assist to minimize leakage of water between the outlet end of the heatable section <NUM> and the connector member <NUM>. The seal <NUM> can be formed of any suitable material, such as an elastomer, e.g. silicone rubber.

The connector member <NUM> may include a recess <NUM> in which the outlet end of the heatable section <NUM> is receivable. In the non-limiting example shown in <FIG> and <FIG>, the outlet end of the heatable section <NUM> is received in the recess <NUM> of the connector member <NUM> together with the seal <NUM>.

The connector member <NUM> may include a connector portion <NUM> to which the further tubing section <NUM> is connectable, for example by an end of the further tubing section <NUM> being sleeved around the connector portion <NUM>.

In embodiments, such as that shown in <FIG>, <FIG> and <FIG>, in which the sensor <NUM> includes the pair of electrodes 122A, 122B, the connector member <NUM> may delimit holes 148A, 148B through which the electrodes 122A, 122B extend from an outside of the connector member <NUM> to the inside of the connector member <NUM>. The electrodes 122A, 122B may thus extend to the inside of the connector member <NUM> where the electrodes 122A, 122B can make contact with the heated water. Outside the connector member <NUM>, the electrodes 122A, 122B may be connected to a sensing circuit of the sensor <NUM>, e.g. a sensing circuit of the type shown in <FIG>.

It is reiterated that <FIG> and <FIG> depict an example in which the heatable section <NUM> comprises a heating tube that includes the heating element <NUM> as an integral component.

Evident in <FIG> and <FIG> are the electrical connections 149A, 149B by which the heating element <NUM> can be connected to control circuitry, e.g. the controller. The heating element <NUM> extends from an electrical connection 149A that is proximal to the outlet end of the heatable section <NUM> to another electrical connection 149B that is proximal to an inlet end of the heatable section <NUM>.

The water flow rate in heating tubes in production may be difficult to control, for instance due to variation in power, inner diameter, etc., partly due to such heating tubes being a relatively low-cost component. However, the actual appliance water flow rate may be measured during production, and the production fixture may automatically program this data to the controller, e.g. the microcontroller unit.

<FIG> and <FIG> can be regarded as depicting a water heating and sensing assembly <NUM> comprising the heatable section <NUM>, at least part of the sensor <NUM>, and the connector member <NUM> configured to house the at least part of the sensor <NUM>, e.g. the electrodes 122A, 122B.

The water heating and sensing assembly <NUM> is shown in <FIG> in a partially disassembled state, with the connector member <NUM> being detached from the heatable section <NUM>, and the at least part of the sensor <NUM>, in this case the electrodes 122A, 122B, being detached from the connector member <NUM>.

The water heating and sensing assembly <NUM> is shown in <FIG> in an assembled state with the connector member <NUM> being attached to the heatable section <NUM>, at the outlet end of the heatable section <NUM>, and with the at least part of the sensor <NUM>, in this case the electrodes 122A, 122B, being housed and mounted within the connector member <NUM>.

<FIG> provides a flowchart of a method <NUM> according to an example. The method <NUM> is a method <NUM> of operating a coffee brewing apparatus <NUM> according to any of the embodiments described herein.

The method <NUM> comprises initiating <NUM> power supply to heat the water in the heatable section <NUM>. The initiating <NUM> may, for example, be implemented by the user switching on the coffee brewing apparatus <NUM>, e.g. by actuating a power switch.

In step <NUM>, a start of bubbling in the tubing <NUM> following the initiation <NUM> of the power supply is determined based on sensory data received from the sensor <NUM>. The method <NUM> also comprises controlling <NUM> heated water delivery to the receptacle <NUM> based on the determined start of bubbling.

In some embodiments, and as described above in relation to the coffee brewing apparatus <NUM>, the sensor <NUM> comprises a pair of electrodes 122A, 122B for contacting the water in the tubing <NUM>. In such embodiments, the sensory data may comprise a measure of resistance or current between the pair of electrodes 122A, 122B.

In some embodiments, the controlling <NUM> heated water delivery to the receptacle <NUM> comprises controlling heating of the water in the heatable section <NUM>.

Alternatively or additionally, the controlling <NUM> the heated water delivery to the receptacle <NUM> may be based on a duration that begins with the determined start of bubbling.

In such embodiments, the controlling <NUM> the heated water delivery to the receptacle <NUM> may comprise reducing or stopping the power supply, e.g. to the heating element <NUM>, that heats the water in the heatable section <NUM> following completion of the duration.

In some embodiments, the method <NUM> comprises receiving a user input of a desired quantity of brewed coffee to be produced, with the controlling <NUM> the heated water delivery to the receptacle <NUM> being based on the determined start of bubbling and the user input.

For example, the user input, e.g. via a user interface included in the coffee brewing apparatus <NUM>, may be used to set the duration timed by the timer that begins with the determined start of bubbling.

In this manner, the quantity of brewed coffee produced need not depend simply on a volume of water in the reservoir <NUM>, nor on power supply to the heating element <NUM> being manually terminated by the user.

A computer program is also provided, which computer program comprises computer program code which, when executed on a computing device having a processing system, causes the processing system to perform steps of the method <NUM> according to any of the embodiments described herein, and in particular steps <NUM> and <NUM>. The processing system may be, for example, included in the controller of the coffee brewing apparatus <NUM>.

Claim 1:
A coffee brewing apparatus (<NUM>) comprising:
a reservoir (<NUM>) for holding water;
a receptacle (<NUM>) for containing coffee grounds;
a delivery outlet (<NUM>) at which water is supplied into the receptacle;
a one-way valve (<NUM>);
tubing (<NUM>) for carrying water from the one-way valve to the delivery outlet, a heatable section (<NUM>) of the tubing being configured such that water in the heatable section is heated to generate water vapor bubbles, and the delivery outlet being at an elevated position, in use, relative to the heatable section, wherein the one-way valve is arranged to permit water transport therethrough from the reservoir towards the heatable section but restrict transport of the heated water comprising said water vapor bubbles from the heatable section back towards the reservoir, the heated water comprising said water vapor bubbles being thereby caused to rise in the tubing from the heatable section to the delivery outlet;
a sensor (<NUM>) configured to sense bubbling in water in the tubing between the heatable section and the delivery outlet; and
a controller configured to:
determine, based on sensory data from the sensor, a start of bubbling in the tubing between the heatable section and the delivery outlet following initiation of power supply to heat the water in the heatable section; and
control heated water delivery to the receptacle based on the determined start of bubbling.