AU2019100677B4

AU2019100677B4 - Baby mode for a heating vessel

Info

Publication number: AU2019100677B4
Application number: AU2019100677A
Authority: AU
Inventors: Andrew Chan; Sarah Francis; Maxim Guyatt; Nick O'loughlin; Alex Tofaili; Mark Whitcombe
Original assignee: Sunbeam Corp Ltd
Current assignee: Newell Australia Pty Ltd
Priority date: 2013-09-24
Filing date: 2019-06-21
Publication date: 2019-10-17
Anticipated expiration: 2022-09-24
Also published as: AU2014233565A1; AU2019100677C4; AU2019100677A4

Abstract

A heating vessel is described for heating water in a baby mode. A selection means is provided for entering the baby mode. There is a control means responsive to the selection means and a heating element operable to apply heat to water held in the heating vessel. A temperature sensor generates a temperature signal related to a temperature of the water. The control means is arranged in response to activation of the selection means, to switch on the heating element to heat the water to a boiling point that is sensed by the temperature sensor, and to switch off the heating element to allow the water to cool to a target baby mode temperature. An indicator is configured to provide an indication when the temperature sensor senses that the target baby-mode temperature is reached.

Description

Baby mode for a heating vessel

This application is a divisional application of Australian Patent Application No. 2014233565, the entire contents of which is incorporated herein by reference in its entirety.

Field of the invention

The present invention relates to heating vessels and in particular to heating vessels that include temperature sensors for accurately detecting the temperature of the heating vessel’s contents during operation.

Background of the invention

Heating vessels (such as kettles, percolators, mocha makers, rice cookers, slow cookers and electric fry ware) are commonly used to prepare food and drinks. These heating vessels generally include an electric heating element which heats a contact plate via a heat distribution plate. The heating surface of the contact plate is in direct contact with the vessel’s contents.

In preparing food for young children it is desirable to heat food and drink, but not to an extent where scalding or discomfort might arise. This is particularly the case with infants, where sterilisation may be necessary.

Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be combined with other pieces of prior art by a skilled person in the art.

Summary of the invention

According to one aspect of the invention there is provided a method for heating water in a heating vessel in a baby mode, the method comprising:

entering a baby mode in response to a baby mode selection step, the baby mode including:

switching on a heating element to heat the water to boiling point;

1002609433 switching off the heating element to allow the water to cool to a target baby-mode temperature;

indicating when an intermediate target temperature is reached between the boiling point and the target baby-mode temperature; and indicating when the target baby-mode temperature is reached.

According to another aspect of the invention there is provided a heating vessel for heating water in a baby mode, comprising:

a selection means for entering the baby mode;

a control means responsive to the selection means;

a heater operable to apply heat to water held in the heating vessel;

a temperature sensor that generates a temperature signal related to a temperature of the water;

the control means being arranged in response to activation of the selection means, to switch on the heater so as to heat the water to a boiling point that is sensed by the temperature sensor, and to switch off the heater to allow the water to cool to a target babymode temperature; and an indicator configured to provide an indication when the temperature sensor senses that the target temperature is reached, wherein the control means is arranged to monitor the temperature signal and to initiate an output indication when the temperature signal reaches an intermediate temperature value between the boiling point and the target baby-mode temperature.

Brief description of the drawings

An embodiment of the invention is now described with reference to the drawings, in which:

Figure 1 is a cross-sectional view of an electric kettle;

Figure 2 is a partially cut-away view of a heater assembly for the kettle of Figure 1;

Figure 3 shows more detail of the heater assembly of Figure 2 including an electronic temperature sensor;

Figure 4 shows a cross-sectional view of part of the heater assembly;

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Figure 5 is a flow diagram of a method for controlling the operation of the kettle, including displaying a predicted time remaining until a temperature threshold is reached;

Figure 6 is a flow diagram of a method for heating water in an electric kettle in a baby mode; and

Figure 7 is shows an example of a powered base unit for the electric kettle.

Detailed description of the embodiments

Heating vessels (such as kettles and percolators) are in common use and are often used to bring liquid contents to the boil or some other desired temperature. The rate of heating depends on factors such as the initial temperature of the liquid contents and the volume of liquid present in the vessel relative to the power available to heat. The arrangements described herein include a data display that provides an estimate of the time required for the contents of the heating vessel to reach a specified temperature, such as the boiling point of water or a temperature suitable for preparing food for young children and babies. The described embodiment relates to a kettle, but it will be appreciated that similar arrangements may be used in other heating vessels.

Description of kettle with temperature sensor

Figure 1 shows a cross-sectional view of an electric kettle 10. The electric kettle has a heating chamber 12, which holds the water to be boiled. The water may be poured into the heating chamber 12 of the kettle through the pouring spout 14. The base wall of the heating chamber 12 is defined by a contact plate 16. Water stored in the heating chamber 12 is in direct contact with one side of the contact plate 16. The contact plate 16 is formed from stainless steel. Other materials which are suitable for contacting water and are resistant to high temperatures and oxidation may be used.

The contact plate 16 forms part of a heater assembly 18. The heater assembly is generally located underneath the internal chamber 12 on the opposite side of the contact plate to the heating chamber 12. One embodiment of the heater assembly 18 is shown in greater detail in Figures 2 to 4. The heater assembly 18 is powered by a power source (not shown) which is external to the kettle 10. The power may be transmitted to the heater assembly 18 using known techniques, for instance through a plug-in electrical lead. The depicted kettle is a single unit. In other arrangements the kettle may have a cordless vessel that is placed on a powered base unit for the vessel’s contents to be heated.

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The heat used to boil the water is generated by a heating element 20, which terminates in cold tails carrying electrical connections 22. Preferably the heating element 20 is powered by electricity. The heating element 20 shown is a resistance element. Other types of heating elements may be used.

The heating element 20 is bonded to a heat distribution plate 24. The bonding achieves a good thermal coupling between the heating element 20 and the heat distribution plate 24 so that heat generated by the heating element 20 is rapidly and efficiently transferred to the heat distribution plate 24. Many known bonding techniques are suitable including induction welding, flame or oven welding and impact welding. Alternatively the heating element 20 may be mounted to the heat distribution plate 24 using other known techniques, such as mechanical fasteners.

The heat distribution plate 24 is induction brazed to the contact plate 16 so there is a good thermal coupling between the heat distribution plate 24 and the contact plate 16. Many other known bonding techniques are suitable, including the bonding techniques mentioned above.

The heat distribution plate 24 is formed from aluminium, which is a good thermal conductor, and is of sufficient thickness so that heat is evenly distributed over the contact plate 16. Alternative materials for the heat distribution plate 24 include other metals and metal alloys. The heat distribution plate 24 is generally thicker than the contact plate and formed from a material which is a better thermal conductor than the contact plate 16.

The heat distribution plate 24 defines a void 26 in the vicinity of the cold tails 22. The void 26 forms a thermally insulating zone. This is because heat which is transmitted from the heating element 20 to the heat distribution plate 24 is not as readily transmitted across the void 26. The region of the contact plate 16 located in the void 26 does not conduct significant amounts of heat when compared to the aluminium heat distribution plate because the contact plate 16 is thin and formed from stainless steel, which is not as good a thermal conductor.

Mounted in the void 26 is an electronic temperature sensor 28. The void 26 provides a thermally insulating zone around the electronic temperature sensor 28. Heat from the heat distribution plate 24 is not readily transmitted to the electronic temperature sensor 28. As a result, the electronic temperature sensor 28 is thermally insulated and is not undesirably influenced by the temperature of the heating element 20 and heat distribution plate 24.

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Preferably the thermally insulating zone and the temperature sensor 28 are located between the cold tails 22 of the heating element 20. The cold tails do not generate significant amounts of heat, so the electronic temperature sensor 28 is further insulated from the heat generated by the heating element 20. Instead of being empty, the void 26 may be filled, either partially or wholly, with an insulating material, such as silicone or rubber.

The temperature sensor 28 is mounted in close proximity to the contact plate 16. Optionally, the temperature sensor 28 may be touching the contact plate 16. This improves the thermal coupling between the electronic temperature sensor 28 and the contact plate 16. The thermal coupling may be further improved using known techniques, such as applying a heat transfer paste.

It is an advantage that the temperature sensor 28 is in thermal contact with the contact plate 16 in the region indicated by 29. When water contained in the heating chamber 12 of the kettle 10 heats up, the contact plate 16 will heat to a similar temperature. Due to the void 26, the region of the contact plate 16 located within the void is insulated from the heat distribution plate 24 and will more accurately reflect the temperature of the water. Since the temperature sensor 28 is in thermal communication with the contact plate 16, it senses the water temperature with greater accuracy and responsiveness. Thus, the temperature measured by temperature sensor 28 is related to the temperature of the material in the chamber 12.

Figures 2 to 4 show the temperature sensor 28 being supported by a sensor support 30. The sensor support 30 is formed from silicone, and is held in place by a bracket 32. Other insulating materials are also suitable. The bracket 32 is mechanically fastened to the heat distribution plate 24. The bracket 32 is preferably formed from a relatively rigid material, such as a plastic, metal or metal alloy. The bracket 32 locates the sensor support 30 in the centre of the void 26 so the sensor 28 is insulated and may press the sensor support 30 against the contact plate 16, providing a good thermal connection between the sensor 28 and the contact plate 16. The temperature sensor 28 may be mounted in a number of ways which aim to minimise the influence of heat from the heat distribution plate 24.

The temperature sensor 28 may be a thermistor. NTC thermistors formed from metal oxides are suitable. A thermistor has a number of advantages over other types of temperature sensors. A thermistor senses the temperature of water in the kettle within a continuous range. This provides significantly more information on the temperature of the

1002609433 water than, for example, a bimetallic actuator. A bimetallic actuator is typically activated only when the water reaches a threshold temperature value and is deactivated when the water fall below a threshold temperature value. As a result, a bimetallic actuator only senses whether the water temperature is above or below a threshold value. The thermistor provides responsive and accurate readings because it is mounted in a thermally insulating zone in direct thermal communication with the contact plate 16.

The heater assembly 18 shown in Figures 2 to 4 has a single void 26 in which the temperature sensor 28 is located. It is also possible to have multiple voids around the temperature sensor. Each void forms a thermally insulating region. By positioning a number of the thermally insulating regions around the sensor 28, a thermally insulating zone is formed. The sensor 28 is still mounted in direct thermal contact with the contact plate 16.

The contact plate 16 shown in Figures 2 to 4 is free of indentations, and in one arrangement is uniplanar. This shape improves the accuracy of the temperature sensor 28. Because the contact plate 16 is free of indentations, water contained in the heating chamber 12 of the kettle 10 is able to readily and rapidly mix. This means the temperature of water located immediately above the temperature sensor 28 is more likely to accurately reflect the temperature of the remaining water volume contained in the kettle 10. Consequently the temperature sensor 28 gives more accurate readings of the temperature of all of the water in the kettle 10. Other configurations of contact plate 16 may also be used. For example, the contact plate may be concave or convex, or may include a dome-shaped protrusion in the vicinity of the temperature sensor 28.

While temperature sensor 28 has been described with reference to the drawings, it would be appreciated that other temperature sensors could be used, such as those described in AU2007250521 and AU2012265567.

Heat source controller

Referring again to Figures 2 to 4, the heater assembly 18 has a heat source controller. The heat source controller is electronically connected to the temperature sensor 28 and the heating element 20. The heat source controller controls the operation of the heating element 20 with reference to the temperature sensed by the temperature sensor 28. Preferably, the controller is made up of an electronic circuit or number of electronic

1002609433 circuits including a microprocessor. These circuits may be designed in a number of ways to provide the functionality described below.

The heat source controller may have a number of different functions, such as a boil function, a keep warm function and a baby mode, which use feedback from the temperature sensor 28.

The functions of the kettle 10 may be operated by a button arrangement, for example one or more momentary push buttons. The buttons are connected to, and provide input to, the controller.

When a start button is activated, the controller enters a boil mode. Before activation, the controller is in a standby mode. After activation, the controller enters the boiling mode. When in the boiling mode, the controller turns on the heating element 20 and begins to heat the water in the kettle. The controller may in addition cause an illuminated ring to produce, for example, red light, to indicate the controller is in the boiling mode and the water is being boiled.

The temperature sensor 28 detects when an upper boiling limit has been reached. The upper boiling limit may be 97°C, though other limits may be used. At this point the controller enters a boiled mode. In the boiled mode, the controller turns off the heating element 20 and the red light in the illuminated ring. The controller may then turn on, for example, a green light to indicate that the water is boiled.

In the boiled mode, the temperature sensor 28 continues to sense the temperature of the water. After the heating element 20 is turned off, the water slowly cools. Once the temperature of the water falls to a lower boiling limit, the controller ends the boiled mode and returns to standby mode. At this stage, the controller may turn off the green light to indicate the water is no longer at or near boiling temperature. A suitable lower boiling limit is 92°C, though other limits may also be used.

Display

The kettle 10 has a display for presenting data to a user. In one arrangement the display is a liquid crystal screen that may display three or more lines of alphanumeric text. Other types of display may also be used, including a display using light-emitting diodes (LEDs). The display is driven by the controller and may be used to display information relating to the measured temperature and the current state of the kettle 10. As described below, the

1002609433 display may be used to indicate the expected time remaining until the water in the kettle boils.

In one arrangement the display has three lines of text. The first line shows the temperature measured by the temperature sensor 28. The second line indicates a state of the kettle, for example “Standby”, “Boiling”, “Boiled” or “Ready for Baby”. The third line shows the estimated time until the water in the kettle boils or reaches a specified threshold value.

In other arrangements where the kettle has a cordless vessel that is placed on a powered base unit for the vessel’s contents to be heated, the display may be provided on the powered base unit.

Predicting the time to boil and the time to cool

Figure 5 illustrates a method 100 for predicting the time required to boil and/or cool the water in the kettle. The method 100 may be used with the kettle 10, but may also be used with other heating vessels having a temperature measurement and a controller for predicting a time required to reach a temperature threshold.

In step 101 the temperature sensor 28 generates an electric signal indicative of an initial temperature of water in the kettle. The signal is provided to the controller.

In step 103 a user presses the start button of the kettle 10. In response to this action, the controller switches on the heating element 20. In step 105 the controller monitors the output of the temperature sensor 28 and determines the rate at which the measured temperature increases. In one arrangement the rate determination may be performed by code executed by the microprocessor. Alternatively, the rate may be determined by dedicated circuitry in the controller that, for example, generates a derivative of the output of the temperature sensor 28.

To improve accuracy, the controller may determine an averaged rate of temperature increase rather than an instantaneous rate. For example, the controller may wait for a preset time after the heating element 20 is switched on before providing a measurement of the rate of increase of temperature. In one arrangement the controller waits for 10 seconds and then emits a rate measurement calculated as:

Rate = (T10-T0)/10 (Equation 1) where T10 is the measured temperature after 10 seconds and TO is the initial temperature. The determined rate is thus the average rise over 10 seconds.

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If the initial temperature is high, for example over 90°C, the controller may wait for a shorter time, for example 5 seconds, before providing the rate measurement.

As the controller is waiting for the preset time before providing a measurement, the kettle 10 may be configured to provide an indication that the kettle 10 is calculating. For example, the display or a light may blink.

Other techniques of averaging the rate of temperature increase may also be used. Once the controller has started outputting the rate of temperature increase, a rolling average of the rate may be produced. For example, a rolling average may be calculated as:

Average rate = AVERAGE(((T10-T0)/10, (T11 -T 1)/10, (T12-T2)/10) where an average of three recent rates is determined and updated progressively.

During the initial period after the heating element is switched on, the display may indicate that the controller is busy calculating. For example, the word “Calculating” may appear on the display.

Once the measured rate of temperature increase is available, in step 107 the controller uses the measured rate to predict how long it will take the measured temperature to reach a temperature threshold Tthresh. In the preferred embodiment the threshold is a temperature value that corresponds to the water boiling. The predicted time may be calculated using a linear extrapolation of the rate determined in equation 1:

(Time remaining) = (Tthresh-T)/Rate (Equation 2) where T is the current temperature and Tthresh is the specified threshold temperature.

In step 109 the time remaining is displayed. The controller includes a clock, enabling the displayed time to be shown in a count-down manner. The displayed time thus diminishes from the value calculated in equation 2 towards zero.

In step 111 the controller checks whether the current temperature has reached Tthresh. If this is the case (the Yes option of step 111) then in step 113 the controller switches off the heating element 20 and clears the display of the remaining time.

Preferably, the controller continues to monitor the rate of temperature increase, as this enables the time prediction to be updated. For example, if water is added to the kettle 10 the current temperature can change, affecting the time required to reach Tthresh. If the controller determines that the current temperature has not been reached (the No option of

1002609433 step 111), control flow returns to step 105 to obtain an updated value for the rate of temperature increase. The updated rate is then used in step 109 to revise the time prediction using equation 2. The updated value of the rate is preferably an averaged value, for example the average increase in the previous 5 or 10 second interval.

If the revised time prediction differs from the currently displayed value of time remaining, the displayed value changes. For example, if water is added to the kettle 10, the displayed ‘time until boiling’ increases.

The method 100 may also include safety checks. For example, if the rate of temperature increase determined in step 105 is greater than or equal to a specified upper value, the controller may act to cut off the heating element. This condition may arise if the kettle is empty or if the contents have boiled away.

Time to cool

In a further arrangement, as illustrated in step 115 of Figure 5, the controller monitors the output of the temperature sensor 28 and determines a rate of temperature decrease after the heat element 20 has been switched off. Then, in step 117 the temperature of the water is displayed.

In one embodiment, the time predicted includes the total time required to boil and cool the water in the kettle. Accordingly, the kettle can display the time remaining for the water to boil and then to cool.

Baby mode

The heating vessel may be provided with a baby mode, in which water can be boiled to sterilise the water and then allowed to cool to a temperature suitable for use in food preparation, particularly the preparation of food for infants.

Figure 6 illustrates a method 200 for heating water in a heating vessel in a baby mode. The method 200 may be used with the kettle 10, but may also be used with other heating vessels having a temperature sensor and an indicator to indicate that certain temperatures are reached.

In step 202, the baby mode is initiated by a user input on a selection means, for example, a button or key on a display. In response to this action, the controller switches on the heating element 20. The water is heated to a boil temperature value that is sensed by the temperature sensor 28. As described with reference to Figure 5, the controller can predict

1002609433 how long it will take to reach a temperature threshold and the time remaining can be displayed. In the baby mode, the temperature threshold is the boil temperature value. The boil temperature value may be a specified temperature at which water boils in order to sterilise the water.

In step 206, the controller checks whether the current temperature has reached the boil temperature value. If this is the case (the Yes option of step 206) then in step 210 the controller switches off the heating element 20. Additionally, there may be a step 208 at which the controller operates the heating element 20 so as to maintain the temperature of the water at the boil temperature value for a first specified time. In one arrangement, step 208 may involve maintaining the boil temperature value for at least 5 minutes, which is the time typically taken to sterilise water.

The kettle may also provide an indication that the boil temperature has been reached and/or the boil temperature has been maintained for the specified time. This indication may be in the form of audio, visual and/or haptic feedback. For example, the display may read “Boil temperature has been reached”, or a light may be illuminated (or change colour) to show that the boil temperature has been reached, or a beeper may sound intermittently.

Once the heating element 20 is switched off in step 210, the water in the kettle cools gradually until a target baby mode temperature value is reached. The target baby mode temperature value may be programmable. In one arrangement, a target baby mode temperature may be 37°C to correspond to body temperature. However, this target babymode temperature may vary. In other arrangements, the target temperature may be programmed in the range of 30°C to 50°C.

In steps 212 and 214, the controller determines the rate of the temperature decrease and predicts the time remaining before the target baby mode temperature is reached. The time remaining may be displayed. This determination is calculated in a similar method to the predictions of rate change described with reference to Figure 5. However, in steps 212 and 214, the controller measures the rate of decrease of temperature.

In step 216, the controller checks whether the current temperature has reached the target baby mode temperature value. If this is the case (the Yes option of step 216) then in step 218, an indicator can provide an indication that the target baby mode temperature is reached. This indication may be in the form of audio, visual and/or haptic feedback. For example, the display may read “Baby mode temperature has been reached”, or a light may

1002609433 be illuminated (or change colour) to show that the baby-mode temperature has been reached.

In step 220, the controller operates the heating element 20 so as to maintain the temperature of the water at the target baby-mode temperature value for a second specified time. The second specified time may be programmable. Also, the kettle may display a time remaining until the second specified time is reached. Alternatively, the kettle may display a time elapsed since it has reached the baby-mode temperature.

In the baby mode, the electric kettle carries out steps 202, 204, 206, 210, 216 and 218. Accordingly, steps 208, 212, 214 and 220 are considered optional steps.

For example, the target baby mode temperature may be programmed to be 40°C and the second specified time programmed for 5 minutes. After the water has boiled and cools to 40°C, the kettle provides an indication the temperature of the water is 40°C and the controller maintains the temperature of the water at 40°C for 5 minutes. The kettle may display the time remaining by counting up or counting down the remaining time.

In a further arrangement, the kettle alerts the user when the water in the kettle has cooled to 70°C. This is a recommended temperature for mixing baby formula. The kettle emits an audible beep once the temperature cools to 70°C. A carer may then pour the water into a sterilised bottle in order to mix the formula. A visual indication of the temperature may also be displayed.

The temperature of 70°C may be the target temperature of steps 216 and 218. Alternatively, the 70 °C may be an intermediate target temperature. After alerting the user to a 70°C temperature, cooling may proceed and the method 200 alerts the user once a further target temperature (e.g. 40°C) is reached. Other intermediate temperatures may be used.

If the kettle is about to boil dry (that is, the water in the kettle has substantially evaporated), the temperature detected by the sensor 28 increases rapidly. If this rapid increase is detected, the controller deactivates the baby mode and resumes the standby mode to avoid the kettle boiling dry.

The controller may be provided with an alert function to indicate that the kettle or its contents have been disturbed. For example, once the water has boiled, the controller may check whether the kettle has been moved or its contents have been altered. In one

1002609433 arrangement, the controller monitors for a constant rate of temperature decrease. When the rate of temperature decrease changes suddenly (for example, a sharp rise or fall in temperature), it may indicate that more water has been added to the heating chamber 12. In another arrangement, the controller monitors whether the signal between the kettle and powered base unit is not broken for longer than a specified period (for example, 1 second). In circumstances where the controller detects a potential tampering with the kettle or its contents, a ‘Disturbed’ indication may be provided. This indication may be in the form of audio, visual and/or haptic feedback. For example, the display may read “Disturbed”, or a light may be illuminated (or change colour) to show that the kettle’s position has changed or its contents have been altered. Additionally, the controller may terminate the baby mode or keep warm functions. The ‘Disturbed’ alert function can be provided on the controller regardless of whether the kettle is in the baby mode or whether the keep warm function is activated. The controller may be provided with a reheat function so that regardless of the current water temperature, the controller can operate the heating element 20 to allow the temperature of the water to reach the target baby mode temperature, provided that the temperature of the water has previously reached the boil temperature value (step 206) within a predetermined time period. Alternatively, the reheat function may only operate provided the temperature of the water has previously reached the boil temperature value (step 206) and was maintained at the at the boil temperature value for the first specified time (step 208). During the reheat function, once the target temperature is reached, the target temperature is then maintained for the second specified time. For example, a user may wish to use the reheat function after the kettle has already once operated in the baby mode and the temperature of the water in the kettle has dropped below the target baby mode temperature value. Alternatively, the reheat function can be selected even after the ‘Disturbed’ indication was provided. For example, the kettle may have been moved as some of the water was removed.

Figure 7 illustrates an example of a powered base unit 700 for a kettle. A display 702 may be provided on the powered base unit 700. The display 702 can provide various indications such as the current temperature, the time remaining, the time elapsed, a specified time period entered by the user, and whether the water has been sterilised.

A user may activate the baby mode by interacting with a selection means. The selection means may include one or more buttons, such as button 704. For example, in response to a first user interaction, such as pressing button 704, the controller can initiate the method 200

1002609433 (Figure 6) to boil water in the baby mode. In response to a second user interaction, such as a pressing and holding button 704, the controller may initiate the reheat function. Button 704 may be provided with an indication, such as LED lighting to highlight the word “Sterilized”, to indicate whether the controller is performing the method 200 including step 208 to boil and sterilise the water. Button 704 may also be provided with an indication, such as LED lighting to highlight the word “Bottle Warm 40°C”, to indicate whether the controller is performing the reheat function. Alternatively, the sterilize and reheat functions may be provided on separate buttons.

The powered base unit 700 may also include buttons to activate other functions such as the boiling mode 706, keep warm function 708 and temperature settings 710 heat the water to specific temperatures such as 80°C, 85°C, 90°C and 95°C. In some embodiments, the buttons may be used to select a mode of operation and a separate button or switch may be used to activate the mode.

The kettle may be provided with a water level indicator to measure the amount of water to be boiled. The water level indicator can include a window through which the water level can be visually observed, and line markings to indicate particular measurements for the volume of the water in the vessel. In one arrangement, the measurements can be provided as specified increments e.g. 250 ml, 500 ml, 1000 ml. In another arrangement, the measurements can be provided in terms of volumes suitable to fill a baby bottle. For example, a small-sized baby bottle may hold 150 ml of liquid and a large-sized baby bottle may hold 270 ml of liquid. The line markings provided on the water level indicator may account for evaporation during the boiling mode or keep warm function. For example, the line marking can be shown as a ‘fill to this line’, which will measure out a volume of water greater than 270 ml in order to provide a volume of water close to 270 ml after boiling.

Many alternative embodiments of the present invention are possible without departing from the principles of the present invention. For instance, different configurations of kettle and different temperature sensors may be used. Different displays may be used to indicate the predicted time. For example, rather than (or in addition to) using an alphanumeric display, a graphic display may be used. A bar graph may indicate the overall time to reach the threshold, overlaid with a second bar graph indicating what proportion of the total time has elapsed. If the predicted overall time changes, the proportion indicated by the second bar graph is adjusted accordingly. Other graphic objects may also be used, for example a

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2019100677 21 Jun 2019 circle indicating the predicted overall time with an incrementing pie-segment showing the proportion of time that has elapsed.

The principles of the present invention may be applied to other types of heating vessels, such as percolators, mocha makers, rice cookers, slow cookers and electric fry ware. In each case, the vessel has an electronic sensor that provides an indication of the temperature of the vessel contents. The vessel also has a controller for predicting how long it will take for the contents of the vessel to reach a specified temperature and a display for displaying the predicted time.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

The term “comprises” (or its grammatical variants) is used in this specification as equivalent to the term “includes” and neither term should be taken as excluding the 15 presence of other elements or features.

Claims

Claims

1. A heating vessel for heating water in a baby mode, comprising:

a heating element operable to apply heat to water held in the heating vessel;

a temperature sensor that generates a temperature signal related to a temperature of the water;

a selection means for entering the baby mode;

a control means responsive to the selection means, the control means being arranged, in response to activation of the selection means, to switch on the heating element to heat the water to a boiling point that is sensed by the temperature sensor, and to switch off the heating element to allow the water to cool to a target babymode temperature; and an indicator configured to provide an indication when the temperature sensor senses that the target baby-mode temperature is reached, wherein the control means is arranged to monitor the temperature signal and to initiate an output indication to alert a user when the temperature signal reaches an intermediate temperature value after cooling from the boiling point and before reaching the target baby-mode temperature.
2. The heating vessel as claimed in claim 1, which further includes means for predicting a time remaining until the target baby-mode temperature is reached, and means for displaying the time remaining until the target baby-mode temperature is reached.
3. The heating vessel as claimed in claim 1 or 2, which further includes means for predicting a time remaining until the boiling point is reached, and means for displaying the time remaining until the boiling point is reached.
4. The heating vessel as claimed in any one of claims 1 to 3 comprising an audio output and wherein the output indication that the intermediate temperature is reached is audible.
5. The heating vessel as claimed in any one of claims 1 to 4 wherein the intermediate temperature value is 70°C.