Control device for liquid heating appliance

Abstract

A control device for controlling the power supplied to a heater (12) includes a movable electrical contact (6a) that cooperates with a corresponding fixed electrical contact (7a) in a power supply circuit (2) in a closed position and separates from the fixed electrical contact (7a) in an open position to interrupt the supply of power. At an overheat temperature, a thermally sensitive actuator (10a) moves the movable electrical contact (6a) from the closed position to the open position. The control device also includes a solenoid control device that supplies power to an electromechanical solenoid (18) including an induction coil wound around an armature in an interrupting operating mode, causing the armature to move the movable electrical contact (6a) from the closed position to the open position.

Description

Technical Field

[0001] The present invention relates to a control device, in particular a control device for a liquid heating appliance and for interrupting the power supply to a heater in a liquid heating appliance. Background Art

[0002] Some liquid heating appliances, such as kettles, typically include a heating element that is arranged to heat a fixed amount of liquid. Other liquid heating appliances, such as hot water dispensers, typically include so-called flow heaters, in which the heating element is arranged to heat the liquid as it flows through a pipe. In both cases, the appliance typically also includes a control device that is arranged to ensure that the liquid reaches a specific preset temperature, such as boiling, before disconnecting the power supply to the heating element. Furthermore, the control device in the liquid heating appliance typically includes an overheat sensor function so that the power supply to the heating element can be disconnected when an overheating condition is detected.

[0003] Some prior art kettles include a control device that incorporates a thermosensitive actuator in the form of a bimetallic element. Upon heating to a predetermined temperature, the bimetallic element deforms and serves to open a circuit within the control device. Such devices typically require steam to be piped from the heating vessel to the control device in order to heat the bimetallic actuator. An example of such a device can be found in the applicant's earlier application, WO 95 / 34187. As will be appreciated, the provision of pipes increases the number of components within the appliance and can also limit the design freedom of the appliance.

[0004] Alternative arrangements for detecting the temperature of heated liquid within the kettle or being dispensed include electronic control arrangements, in which the temperature of the liquid or heating element is detected by an electronic temperature sensor. The output of such a temperature sensor is typically provided to an electronic control arrangement, which uses an electronic component, such as a triac, to electrically disconnect the power supply when a specific temperature is detected. Examples of such arrangements can be seen in greater detail in the applicant's earlier applications WO 01 / 28294 and WO 2010 / 106349. However, as will be appreciated by those skilled in the art, the use of electronic components, such as triacs, to implement the switching function results in a relatively complex and expensive control arrangement. Summary of the Invention

[0005] The present invention aims to solve or at least alleviate the above problems and therefore when viewed from a first aspect there is provided a control device for controlling a power supply circuit to a heater, for example in a liquid heating appliance, the control device comprising:

[0006] a first movable electrical contact adapted to mate with a corresponding first fixed electrical contact in the power supply circuit in a closed position and to separate from the first fixed electrical contact in an open position to interrupt the power supply circuit;

[0007] a first thermally sensitive actuator operable at an overheat temperature in an overheat operating mode to move the first movable electrical contact from a closed position to an open position; and

[0008] An electromechanical solenoid includes an induction coil wound around an armature and a solenoid control device for supplying power to the electromechanical solenoid in an interrupting operation mode so that the armature operates to move the first movable electrical contact from a closed position to an open position.

[0009] As will be appreciated by those skilled in the art, providing an electromechanical solenoid for moving the first movable electrical contact from a closed position to an open position effectively disconnects the power supply circuit and thereby serves to at least shut off the power supply to the heater. Advantageously, when compared to prior art devices that include a steam-sensitive thermomechanical switch, such a control device may not require a steam conduit for directing steam within the appliance, thereby simplifying the appliance design and potentially reducing associated material and manufacturing costs. Additionally, such a control device may be advantageous over electronic controls in that an electronic switch, such as a triac, is not required. This may reduce the overall cost of the control device. It will further be appreciated that the control device effectively shuts off power to the heater in both the interrupt mode and the overheat mode using the same set of electrical contacts.

[0010] In order to supply power to the heater, the power supply circuit must be closed, i.e. the first movable electrical contact must be in the closed position. A dedicated component acting on the first movable electrical contact to move it to the closed position may be provided. However, in one preferred set of embodiments, the first movable electrical contact is arranged on a resilient member that tends to keep the first movable electrical contact in the closed position. Therefore, it will be understood that in such a set of embodiments, the first movable electrical contact will naturally remain in the closed position unless acted upon by another component. In another set of embodiments, the control device further comprises a movable member that is arranged to act on the resilient member to keep the first movable electrical contact in the open position. The movable member may be arranged to move to a position that allows the resilient member to move the first movable electrical contact to the closed position. The resilient member may, for example, comprise a spring leaf. In other embodiments, such as those in which the first movable electrical contact is not arranged on the resilient member, the movable member may be arranged to move the first movable electrical contact to the closed position by other means. Those skilled in the art will appreciate that movement of the movable member, when the first movable electrical contact is allowed to move to the closed position, effectively closes the power supply circuit and supplies power to the heater.

[0011] In another set of embodiments, additionally or alternatively, the movable member is further operable to move the first movable electrical contact to the open position. Thus, the movable member can be operated to open the power supply circuit and thereby interrupt the power supply to the heater.

[0012] When the armature of the electromechanical solenoid is operative in the interrupting mode of operation, it may act independently of the movable member and directly act on the first movable electrical contact, or a member extending from the first movable electrical contact, to move it from the closed position to the open position. However, in embodiments where the movable member is operable to move the first movable electrical contact to the open position, it is further preferred that the armature is configured to act on the movable member to move the first movable electrical contact from the closed position to the open position. Such an embodiment is particularly advantageous because it may allow for greater freedom in the arrangement of the electromechanical solenoid within the control assembly.

[0013] In one set of embodiments, the control device further comprises a resilient biasing member acting on the movable member and being arranged such that the movable member is either resiliently biased to a first position corresponding to the first movable electrical contact being in an open position, or to a second position corresponding to the first movable electrical contact being in a closed position. The resilient biasing member may, for example, be provided by a control device comprising a spring member arranged to act on the movable member, or an inherent resilient biasing member provided by the movable member itself. Such an arrangement is advantageous because the movable member can maintain the first movable electrical contact in an open position, or allow the first movable electrical contact to be in a closed position, without requiring any further interaction, for example from an electromechanical solenoid, to maintain these positions. This effectively forms a "bistable" arrangement. Therefore, in a preferred embodiment, the movable member is operated in a bistable arrangement between a first position and a second position, for example by a resilient biasing member comprising an eccentric spring arrangement.

[0014] In one such set of embodiments, the user can manually move the first movable electrical contact to the closed position, for example by interacting with the movable member, where the interaction may be indirect. The first movable electrical contact can then remain in that position without the need for further force until the first thermally sensitive actuator or electromechanical solenoid is operated. Once either of these components has operated and moved the first movable electrical contact to the open position, the stability of the movable member in the first position (due to the resilient biasing member) will mean that even if the thermal actuator is reset or the power supply to the electromechanical solenoid is cut off, the first movable electrical contact will remain in the open position until the user acts on it again to move it back to the closed position. Therefore, a manual reset is required to reconnect the power supply circuit to the heater.

[0015] The movable member may be provided by any suitable member. However, in a preferred set of embodiments, the movable member comprises a pivotally mounted lever member. Applicants have recognized that such a pivotally mounted lever member can be readily mounted in a "bistable" arrangement including the aforementioned resilient biasing member. Additionally, a pivotally mounted lever member can be useful because any user-applied force can be amplified, thereby reducing the amount of force required. For example, when the first movable electrical contact is disposed on a resilient member, the amount of force required to move the first movable electrical contact can be reduced.

[0016] In one set of embodiments, the control device further comprises a user operable member, the user operable member being arranged to move the movable member to at least allow the first movable electrical contact to move to the closed position. In a set of embodiments that may overlap, the control device further comprises a user operable member or the user operable member being arranged to move the movable member to move the first movable electrical contact to the closed position. In some embodiments, the user operable member may be arranged to move the movable member to the aforementioned second position. Thus, the user operable member may be used to close the power supply circuit, thereby supplying power to the heater. In another set of embodiments, the user operable member may also be operable to move the movable member to move the first movable electrical contact to the open position. In some embodiments, the user operable member may be arranged to move the movable member to the aforementioned first position. Thus, the movable member may be used as a manual means for disconnecting the power supply (i.e. turning off the heater).

[0017] The user operable member may be provided by any suitable means. In one set of embodiments, the user operable member is provided by an actuating member arranged to directly actuate the movable member. The actuating member may extend directly from the movable member or be attached to the movable member by a connecting rod. Such an arrangement can be relatively simple, thereby keeping the complexity and cost of the control assembly to a minimum. In an alternative set of embodiments, the user operable member is provided by a button arranged to act on the movable member. The button may, for example, comprise a resiliently biased button arranged so that when the user releases the button, it moves back to its original position and no longer acts on the movable member.

[0018] Applicants have recognized that, depending on the type of user-operable member, the user-operable member may not be able to act on the movable member in a manner that causes the first movable electrical contact to move to the open position. For example, it may not be possible to drive the movable member in two opposite directions using a button. Therefore, in one set of embodiments, the control device further includes a touch switch that is electrically connected to the solenoid control device and is configured such that the user-operable member causes a change in the output of the touch switch when operated by the user. For example, the touch switch may be of a type that outputs an electrical signal as long as it is activated but ceases to provide an electrical signal when it is no longer activated. In another set of embodiments, the solenoid control device monitors the output from the touch switch and, depending on the output, supplies power to the electromechanical solenoid in an interrupt mode of operation, causing the armature to operate to move the first movable electrical contact from the closed position to the open position. As will be appreciated by those skilled in the art, the user-operable member can be used to connect and disconnect a power supply circuit by operating the electromechanical solenoid.

[0019] When a user wishes to connect the power supply circuit, they can operate a user-operable member for moving the movable member, causing the first movable electrical contact to move to the closed position. This closes the power supply circuit. Additionally, in doing so, the user-operable member acts on a touch switch, which in turn provides a first output signal to the solenoid control device. The solenoid control device can register the detection of the first output signal but be programmed to ignore it, for example, to identify this as a manual connection. Once the power supply circuit has been closed, the user can release the user-operable member, which may move away from the touch switch, for example, if provided by a resiliently biased pushbutton. If the user subsequently wishes to disconnect the power supply circuit, for example because they have decided they no longer wish to heat liquid, they can operate the user-operable member again. As described above, this may not cause the movable member to move, but it will act on the touch switch and cause another output signal to be provided to the solenoid control device. The solenoid control device can detect the presence of this other output signal and be configured or programmed to identify this as a user's intention to disconnect the power supply circuit. Thus, upon detection of another output signal or upon cessation of another output signal, for example after a user releases the user operable member, the solenoid control device may be configured to supply power to the electromechanical solenoid in an interrupting mode of operation, i.e., to cause the armature to operate to move the first movable electrical contact from the closed position to the open position.

[0020] In one or more embodiments, the solenoid control device may include a control device configured to selectively supply power to the electromechanical solenoid. The control device may be an electronic processor (e.g., a microprocessor) or an analog control circuit. In some embodiments, such a control device may optionally be configured to receive an output signal from a touch switch as described above.

[0021] Those skilled in the art will appreciate that the interrupt mode of operation described above, initiated by a user acting on a user-operable member, is only one possible scenario in which the interrupt mode of operation may occur. The solenoid control device can be configured or programmed to supply power to the electromechanical solenoid based on a number of different factors. The control device, as described above, can determine when to supply power to the electromechanical solenoid. In one set of embodiments, the control device further includes at least one temperature sensor connected to the solenoid control device. The temperature sensor can be configured, for example, to sense the temperature of the heater and / or the liquid being heated by the heater. In one set of embodiments, the solenoid control device monitors a sensor output from the temperature sensor and, depending on the sensor output, supplies power to the electromechanical solenoid in the interrupt mode of operation, causing the armature to operate to move the first movable electrical contact from the closed position to the open position. The solenoid control device can, for example, monitor the sensor output until it reaches a certain threshold, such as corresponding to the heated liquid being at boiling temperature. Thus, the interrupt mode of operation can be initiated based on a temperature condition. The temperature sensor can be provided by any suitable device, however, in a preferred set of embodiments, the temperature sensor is provided by a thermistor, such as a negative temperature coefficient (NTC) thermistor.

[0022] Applicants have recognized that the solenoid control device may utilize one or more additional and / or different parameters to control the activation of the interrupt mode of operation and control of the electromechanical solenoid. Thus, in a set of potentially overlapping embodiments, the solenoid control device is programmed or configured to supply power to the electromechanical solenoid depending on the amount of time that has elapsed since the power supply circuit was closed. Such a set of embodiments may, for example, be applied to embodiments in which the control device is used to control the operation of a heater in a flow heater device, where it is known that a certain amount of time corresponds to a specific volume of water having been dispensed.

[0023] The parameters discussed above, such as temperature and / or time, can be pre-set or predetermined by the solenoid control device. In some examples, this can be achieved by storing preset values for the parameters in a memory associated with the electronic processor. For example, the solenoid control device can continue to supply power to the electromechanical solenoid when the solenoid control device detects a temperature corresponding to boiling and / or after a preset time (e.g., 10 seconds) has elapsed. However, applicants have recognized that it may be advantageous for the user to have more control over the appliance using the control device. Therefore, in one set of embodiments, a user input device is operably connected to the solenoid control device for changing the conditions under which the solenoid control device supplies power to the electromechanical solenoid. For example, the conditions may correspond to one or more parameters such as temperature or time. Such a set of embodiments is advantageous because it allows, for example, a user to change the temperature at which the solenoid control device supplies power to the electromechanical solenoid, thereby effectively controlling the temperature to which the liquid is heated. In some examples, this can be achieved by operably connecting the user input device to the electronic processor, which determines when to selectively supply power to the electromechanical solenoid.

[0024] In various embodiments, the user input device can be an electromechanical input device (such as a knob or dial) or an electronic input device (such as a touch screen). In another set of embodiments, the control device further comprises a display, additionally or alternatively. The display can be arranged to display the parameters changed by the user input device. The user input device can, for example, comprise a potentiometer, which can be manually adjusted by the user, for example, via a knob or dial. Such an arrangement effectively forms a passive user input device. Additionally or alternatively, the user input device can comprise an electronic input device, such as a button operably connected to an electronic processor. Such an arrangement effectively forms an active user input device.

[0025] The provision of the first movable electrical contact is sufficient to open and close the power supply circuit to the heater. However, in one set of embodiments, the control assembly includes a second movable electrical contact and a second thermally sensitive actuator, the second movable electrical contact cooperating with a corresponding second fixed electrical contact in the power supply circuit in the closed position and the second movable electrical contact separating from the second fixed electrical contact in the open position to interrupt the power supply circuit in the open position, and the second thermally sensitive actuator being capable of operating at an overheat temperature in an overheat operating mode to move the second movable electrical contact. Preferably, the second thermally sensitive actuator is operable at a different overheat temperature than the first thermally sensitive actuator. Any features of the above-described embodiments that interact with the first movable electrical contact may also be applied similarly to the second movable electrical contact.

[0026] In one set of embodiments, the control device includes a cordless electrical connector component. In another set of embodiments, the control device includes a base electrical connector component that mates with the cordless electrical connector component. In use, the engagement between the radio component and the base electrical connector component allows power to be supplied to the power supply circuit. The base electrical connector component may include tabs for electrical connection to a mains power cord, or the mains power cord may be integrated with the connector component. Typically, the base electrical connector component is mounted in a power base station for the liquid heating appliance that houses the control device.

[0027] The cordless electrical connector part and the corresponding base electrical connector part may be of a type which can mate regardless of their relative angular orientation, or at least through a wide range of angles, for example at least 340° and preferably up to 360°. Suitable cordless connectors of this "360° type" are described in WO 95 / 08024 and WO 01 / 28294 and may be used as a Strix P72 or P76 connector set.

[0028] The cordless electrical connector component may include at least two mating conductors, one with a positive pole and one with a neutral pole, for connecting to a power supply circuit. Optionally, an additional ground connection may be present. In some embodiments, the cordless electrical connector component is a 3-pole connector component (e.g., for use with a Strix P72). In other embodiments, the cordless electrical connector component is a 5-pole connector component (e.g., for use with a Strix P76). This 5-pole connector component provides both an electrical signal connection and a power connection. In such an embodiment, the solenoid control device may be located in the power base, while the electromechanical solenoid is located in the cordless appliance.

[0029] In one set of embodiments the control means further comprises a dedicated power supply for supplying power to the electromechanical solenoid and the solenoid control means.In an alternative set of embodiments the electromechanical solenoid and the solenoid control means are connected within a power supply circuit such that they are supplied with power from the power supply circuit.

[0030] The control device may be electrically connected to mains power, such as a 240V AC power supply, thereby potentially requiring the voltage applied to the electromechanical solenoid and solenoid control device to be "stepped down." Therefore, according to another aspect of the present invention, there is provided a liquid heater device comprising a control device according to any of the above embodiments, a heater, and a resistive element, the heater comprising a first electric heating element, the first electric heating element comprising a first pair of electrical terminals. The resistive element comprises a second pair of electrical terminals, wherein the resistive element is electrically connected in series with the first electric heating element via an electrical connection between one of the first pair of electrical terminals and one of the second pair of electrical terminals, wherein the first electric heating element has a first resistance and the resistive element has a second resistance different from the first resistance, and wherein the electromechanical solenoid and solenoid control device are electrically connected between one of the first pair of electrical terminals or the second pair of electrical terminals, i.e., across the heating element or across the resistive element.

[0031] Applicants have recognized that connecting a resistive element having a differential resistance in series with the first electrical heating element means that the electromechanical solenoid and solenoid control device can be connected in parallel with the resistive element and supplied with a different voltage and power than the first electrical heating element. This can help avoid the need for complex control electronics. The resistive element can include a second electrical heating element. The second resistance can be lower than the first resistance.

[0032] The electromechanical solenoid and associated solenoid control may require DC current. Therefore, in another set of embodiments, at least one AC-DC converter is provided in series with the electromechanical solenoid and / or the solenoid control.

[0033] The control device or liquid heater assembly described above can be used in a variety of different liquid heating appliances, in particular household liquid heating appliances. According to another aspect of the present invention, a liquid heating appliance is provided, comprising a container with a base and a control device as described above, wherein the base is heated by a heater, and the control device is mounted below the heated base and is configured to control a power supply circuit to the heater. In one or more embodiments, the heater is arranged in the liquid heater device as described above.

[0034] According to another aspect of the present invention, there is provided a liquid heating device comprising a liquid flow heater and a control device as described above, wherein the liquid flow heater comprises a heater and a liquid flow pipe, and the control device is configured to control a power supply circuit to the heater. In one or more embodiments, the heater is arranged in the liquid heater device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Some preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0036] Figure 1 shows a power supply circuit including a control device according to an embodiment of the present invention;

[0037] Figure 2 Shown Figure 1 The power supply circuit shown in , wherein the first movable electrical contact and the second movable electrical contact are both in the closed position;

[0038] Figure 3 An alternative power supply circuit is shown in which an alternative user operable member is provided;

[0039] Figure 4 shows a perspective view of a control device according to one embodiment of the present invention;

[0040] Figure 5 Shown Figure 4 An underside view of the control device shown in ; and

[0041] Figure 6 Shown Figure 4 A perspective view of the control device shown in FIG, with the main body removed to reveal the internal components of the control device. DETAILED DESCRIPTION

[0042] Figure 1 A power supply circuit 2 for a liquid heating appliance including a control device according to some embodiments of the present invention is shown. The power supply circuit 2 is provided with a 240V AC power source 4. The control device comprises a first movable electrical contact 6a and a corresponding first fixed electrical contact 7a. In this particular embodiment, the control device further comprises a second movable electrical contact 6b and a corresponding second fixed electrical contact 7b. The control device further comprises a movable member 8, which is arranged to allow the first movable electrical contact 6a and the second movable electrical contact 6b to move into contact with the corresponding first fixed electrical contact 7a and the second fixed electrical contact 7b. The first movable electrical contact 6a and the second movable electrical contact 6b may comprise electrical contacts arranged on a spring leaf, the spring leaf acting to drive the first movable electrical contact 6a and the second movable electrical contact 6b to a closed position once the movable member 8 has moved to allow the movement. The movable member 8 is also arranged so that its movement can move the first and second movable electrical contacts 6a and 6b out of contact with the first and second fixed electrical contacts 7a and 7b, ie, to an open position.

[0043] The control device further comprises a first thermally sensitive actuator 10a, which is operable at an overheat temperature in the overheat mode to act on the first movable electrical contact 6a and move it to its open position. The control device further comprises a second thermally sensitive actuator 10b, which is also operable at an overheat temperature in the overheat mode to act on the second movable electrical contact 6b and move it to its open position. Of course, the first and second thermally sensitive actuators 10a, 10b do not need to act directly on the first and second movable electrical contacts; instead, for example, they may act on the movable member 8 to move the first and second movable electrical contacts 6a, 6b to the open position.

[0044] Electrically connected in series is an electric heating element 12 of the heater, which can be, for example, a sheathed resistor element. A resistor element 14 electrically connected in series is also provided. The resistor element 14 can be provided by any suitable means, such as another sheathed resistor element. The heating element 12 and the resistor element 14 can have the same resistance or different resistances. In this particular embodiment, the heating element 12 and the resistor element 14 form a voltage divider that divides 15V AC, but this is not necessary and any suitable voltage can be divided. Connected in parallel across the resistor element 14 is a first power supply unit (PSU) 16 that provides a 12V DC output, which supplies power to an electromechanical solenoid 18. As shown in the figure, the electromechanical solenoid 18 (particularly its armature) is configured to act on the movable member 8 so that it can act on the movable member 8 to move the first movable electrical contact 6a and the second movable electrical contact 6b to an open circuit position, that is, to separate the first movable electrical contact 6a and the second movable electrical contact 6b from the corresponding first fixed electrical contact 7a and the second fixed electrical contact 7b.

[0045] The second PSU 20 is electrically connected in series with the first PSU 16 and outputs 5V DC to a solenoid control device in the form of a controller 22. The controller 22 is used to selectively supply power to the electromechanical solenoid 18, i.e. it switches the power supply to the electromechanical solenoid 18 on and off. The controller 22 may be provided by any suitable device, for example, by an analog circuit or a processor.

[0046] A temperature sensor in the form of a negative temperature coefficient (NTC) thermistor 24 is also provided and electrically connected to the controller 22. Of course, any type of temperature sensor that outputs a signal corresponding to the detected temperature may be used. A user interface (UI) 26 is also electrically connected to the controller 22. The UI may allow information to be input and output to and from the controller 22. A touch switch 28 is also electrically connected to the controller 22 and provides additional input to the controller 22.

[0047] A resiliently biased button 30 is also provided, which is arranged so that it can operate the movable member 8 to move the first and second movable electrical contacts 6a and 6b towards the first and second fixed electrical contacts 7a and 7b, i.e. into a closed position (e.g. Figure 2 ). The button 30 is also arranged so that when pressed, the button 30 acts on the touch switch 28 to provide a signal to the controller 22.

[0048] exist Figure 1 In the embodiment, the first movable electrical contact 6a and the second movable electrical contact 6b are in the open circuit position. Figure 2 Shown with Figure 1 The same power supply circuit 2 is shown in FIG, except that the first and second movable electrical contacts 6a, 6b are shown in a closed configuration in which they are in contact with the first and second fixed electrical contacts 7a, 7b.

[0049] The operation of the control means within the power supply circuit 2 will now be described. When a user wishes to switch on the heating element 12, for example to heat the contents of a liquid heating appliance or to dispense a volume of heated liquid, the power supply circuit 2 must first be closed in order to supply power to the heating element 12. Figure 1 and Figure 2 In the embodiment shown, this is achieved by the user pressing the button 30. When the user presses the button 30, this acts on the movable member 8 to move it into a position that allows the first and second movable contacts 6a, 6b to move into a closed position in contact with the first and second fixed electrical contacts 7a, 7b. Figure 2 As shown, once in the closed position, the heating element 12 will be supplied with power and begin to generate heat.

[0050] Pressing the button 30 will also act on the touch switch 28, which will cause an electrical signal to be provided to and detected by the controller 22. The controller 22 may include suitable circuitry or be programmed to record this electrical signal but not necessarily act on it. When the user releases the button 28, due to its resilient nature, it will move back to its original position and no longer act on the movable member 8 or the touch switch 28. This will cause the electrical signal provided by the touch switch to cease, which can also be recorded by the controller 22. The appliance in which the power supply circuit 2 is provided can then continue to operate normally.

[0051] For example, the thermistor 24 may be provided to monitor the temperature of liquid being heated by the heating element 12 in the appliance. The controller 22 may monitor the output of the thermistor 24. When the temperature of the liquid reaches a desired temperature, such as boiling, the controller 22 may register the signal provided by the thermistor 24 and turn on the power supply to the electromechanical solenoid 18. Figure 1 As shown, this activates the electromechanical solenoid 18 and causes its armature to drive the movable member 8, separating the first and second electrical contacts 6a, 6b from the first and second fixed electrical contacts 7a, 7b, moving them to the open position. Once the first and second movable electrical contacts 6a, 6b are separated from the first and second electrical contacts 7a, 7b, the power supply circuit 2 is disconnected and any power supply to the heating element 12 and the electromechanical solenoid 18 is stopped. This mode corresponds to an interruption operating mode in which the power supply circuit 2 is interrupted and heating is thereby interrupted.

[0052] Before the controller 22 automatically decides to interrupt the power supply circuit 2, the user may wish to stop the heating operation, for example, because the user no longer wishes to heat and / or dispense liquid. In this particular embodiment, this can be achieved by the user pressing the button 30 again. This second press will not cause any further movement of the movable member 8, but the button 30 will act on the touch switch 28 and provide a second electrical signal to the controller 22. Upon detecting the second electrical signal, or upon stopping the second detection, for example, by the user releasing the button 30, the controller 22 can be configured or programmed to supply power to the electromechanical solenoid 18. In doing so, the electromechanical solenoid 18 will again act on the movable member 8 to separate the first and second movable electrical contacts 6a, 6b from the first and second fixed electrical contacts 7a, 7b. As described above, this will cut off the power supply to the heating element 12, thereby stopping the operation of the appliance. This effectively provides an alternative interruption mode of operation initiated by the user.

[0053] Another operating mode may also occur, specifically an overheating operating mode. For example, if there is no liquid for the heating element 12 to heat, the heating element 12 may quickly heat up to a high temperature when power is supplied. The thermistor 24 (related to its position) may not be able to detect this rapid increase in temperature, or at least may not be able to detect it quickly enough. Therefore, in this embodiment, the first thermal actuator 10a and the second thermal actuator 10b may be arranged to detect the temperature of the heating element 12. For example, under dry-boil conditions with no liquid present, the heating element 12 will quickly heat up and trigger at least one of the first thermal actuator 10a and the second thermal actuator 10b, which are arranged to separate at least one of the first movable electrical contact 6a and the second movable electrical contact 6b from the corresponding first fixed electrical contact 7a and the second fixed electrical contact 7b, thereby moving them to Figure 1. This disconnects the power supply circuit 2 and thereby interrupts the power supply to the heating element 12, which can avoid damage to the heating element 12 and / or the appliance in which it is arranged, which can help to avoid potential injury to the user. The thermally sensitive actuators 10a, 10b can be provided by bimetallic actuators designed and manufactured to operate at a specific overheat temperature.

[0054] The provision of thermistor 24 is not necessary for operation, but the controller 22 can control the electromechanical solenoid 18 based on another operating parameter. For example, the controller 22 can include an internal timer and can be used to supply power to the electromechanical solenoid 18 after a certain amount of time has passed. This may be appropriate, for example, when a known volume of liquid is being heated by the heating element 12 and / or the heating element 12 has a known power output.

[0055] In this particular embodiment, as previously mentioned, a user interface (UI) 26 is also provided. The UI 26 can serve as a means for, for example, allowing a user to set operating parameters for the controller 22. For example, it can allow the user to change the temperature to which the heater 12 heats the liquid. Additionally or alternatively, it can be used to change the amount of time that the heating element 12 heats the liquid. The user can set these parameters before initiating operation of the appliance. The UI 26 can include, for example, a dial operably connected to a potentiometer for setting the operating parameters. It will be appreciated that such a set of embodiments effectively forms a passive user interface that may not require a power source for setting the operating parameters. Additionally or alternatively, the UI 26 can include electronic buttons or a touchscreen operably connected to the electronic controller 22 for setting the operating parameters. In this case, the UI 26 and the electronic controller 22 effectively form an active user interface that may require a power source for operation. For example, this power source can be provided by a dedicated power source such as a battery (not shown). The UI 26 can also include a display, such as an LCD screen, that can output information to the user, such as the temperature measured by the thermistor 24. However, it will be appreciated that the provision of the UI 26 is optional and can be omitted.

[0056] exist Figure 1 and Figure 2 In the illustrated embodiment, electromechanical solenoid 18 and controller 22, along with associated components, are powered by being arranged in parallel in a voltage divider arrangement. However, this is not required, and a dedicated power source, such as a battery, may be provided for these components. Similarly, a single NTC thermistor 24 is shown; however, this thermistor 24 may be omitted or an additional temperature sensor may be provided.

[0057] Figure 3A second embodiment is shown which is substantially identical to the first embodiment, except that the push button 30 and associated touch switch 28 are omitted and replaced by an actuating member 32 (schematically indicated by a double-headed arrow). Figure 1 and Figure 2 . The same components arranged in the same manner as in the first embodiment shown in FIG. 8 are given the same reference numerals. In this particular embodiment, the movable member 8 can be moved by the actuating member 32 to allow the first and second electrical contacts 6a, 6b to move to the closed position, or directly move the first and second movable electrical contacts 6a, 6b to the closed position, and can also be moved to move the first and second movable electrical contacts 6a, 6b to the open position. Thus, the actuating member 32 can be used to open and close the appliance. This two-way movement is provided by the actuating member 32, which extends directly from the movable member 8.

[0058] In either of the two embodiments described above, the power supply circuit 2 and associated components can be used in a variety of different liquid heating appliances, particularly household appliances. Specifically, the heating element 12 can be configured to heat a static volume of liquid, for example in the form of a kettle, or it can be configured to heat a flow of liquid in a conduit, for example in the form of a flow heater.

[0059] Similarly, in any of the above embodiments, the movable member 8 may be provided with a resilient biasing member so that it is resiliently biased toward a first position corresponding to the first movable electrical contact 6a and the second movable electrical contact 6b being in an open position, or it is resiliently biased toward a second position corresponding to the first movable electrical contact 6a and the second movable electrical contact 6b being in a closed position. The movable member 8 and the associated resilient biasing member may be provided by any suitable means to achieve such a bistable arrangement.

[0060] Figure 4 A perspective view of some components of a control device 134 according to an embodiment of the present invention is shown. The control device 134 includes a body 136 in which a pivotally mounted movable member 108 is mounted. An electromechanical solenoid 118 is disposed at a distal end 140 of the movable member 108. The electromechanical solenoid 118 includes an armature 142 extending therefrom, and the armature 142 is configured to act on the distal end 140 of the movable member 138 to drive movement thereof. The control device 134 includes movable and fixed electrical contacts housed within the body 136, as will be described in greater detail below.

[0061] Figure 5FIG3 shows an underside view of the control device 134. The control device 134 includes a first thermally sensitive actuator 110a and a second thermally sensitive actuator 110b mounted on its underside. Also visible in this underside view is a spring member 144, which acts on the movable member 108 to bias it into one of two positions: a second position in which the first and second movable electrical contacts are in a closed position, and a first position in which the first and second movable electrical contacts are in an open position. The provision of the spring member 144 and the pivotal mounting of the movable member 108 achieve this bi-stable arrangement.

[0062] Figure 6 A perspective view of the control device 134 is shown with the main body 136 removed to expose the internal components of the control device 134. The control device 134 includes first and second movable electrical contacts 106a, 106b and corresponding first and second fixed electrical contacts 107a, 107b. Each thermally sensitive actuator 110a, 110b includes a corresponding actuating rod 146a, 146b, each of which is configured to directly act on the first and second movable electrical contacts 106a, 106b, respectively.

[0063] The movable member 108 includes an interaction portion 148 that is configured to act on the first movable electrical contact 106a. In this particular embodiment, the movable member 108, and in particular the interaction portion 148, is configured to act only on the first movable electrical contact 106a, and not on the second movable electrical contact 106b. However, this is not required, and in an alternative set of embodiments, the movable member may include a first interaction portion and a second interaction portion, each of which is configured to act on the first movable electrical contact 106a and the second movable electrical contact 106b, respectively.

[0064] When the electromechanical solenoid 118 is energized, i.e., supplied with power, the armature 142 is driven onto the distal end 140 of the pivotally mounted movable member 108, which results in pivotal movement of the movable member 108. As the distal end 140 pivots downward, the interacting portion 148 is driven upward into contact with the first movable electrical contact 106a, separating the first movable electrical contact 106a from the first fixed electrical contact 107a, thereby disconnecting the power supply circuit. The first movable electrical contact 106a may be disposed in the neutral pole of the power supply.

[0065] In the above embodiment, a first movable electrical contact and a second movable electrical contact are provided, each of which can be moved together with the associated movable member by a first thermosensitive actuator and a second thermosensitive actuator, respectively. However, it will be understood that the provision of two movable electrical contacts and two associated thermosensitive actuators is not essential, but only a single movable electrical contact and an associated thermosensitive actuator may be provided. Similarly, more than two movable electrical contacts and associated thermosensitive actuators may be provided. Additionally, as in the above embodiment, even in the case where two movable electrical contacts are provided, the movable member may act only on one of these movable electrical contacts in order to disconnect the power supply circuit, while the other movable electrical contact may be acted upon only by, for example, a thermosensitive actuator.

[0066] Although not shown in the above embodiments, the control assembly described may include a cordless electrical connector configured to mate with a corresponding base electrical connector to supply power to the control assembly and any components electrically connected thereto.

Claims

1. A control device for controlling a power supply circuit to a heater, the control device comprising: a first movable electrical contact that mates with a corresponding first fixed electrical contact in the power supply circuit in a closed position and that separates from the first fixed electrical contact in an open position to interrupt the power supply circuit; a first thermally sensitive actuator operable at an overheat temperature in an overheat operating mode to move the first movable electrical contact from the closed position to the open position; as well as an electromechanical solenoid comprising an induction coil wound around an armature and a solenoid control device for supplying power to the electromechanical solenoid in an interrupting mode of operation such that the armature operates to move the first movable electrical contact from the closed position to the open position; The first movable electrical contact is disposed on a resilient member, the resilient member tending to force the first movable electrical contact into the closed position, and the resilient member comprises a spring leaf.

2. A control device according to claim 1, comprising a movable member arranged to act on the resilient member to maintain the first movable electrical contact in the open position.

3. The control device according to claim 2, wherein: The movable member is configured to move to a position that allows the resilient member to move the first movable electrical contact to the closed position.

4. The control device according to claim 2, wherein: The movable member is further operable to move the first movable electrical contact to the open position.

5. The control device according to claim 4, wherein: The armature is configured to act on the movable member to move the first movable electrical contact from the closed position to the open position.

6. The control device according to claim 2 further includes a resilient biasing member, which acts on the movable member and is configured to cause the movable member to be resiliently biased to a first position corresponding to the first movable electrical contact being in the open position, or to be resiliently biased to a second position corresponding to the first movable electrical contact being in the closed position.

7. The control device according to claim 2, wherein: The movable member comprises a pivotally mounted lever member.

8. The control device of claim 2, further comprising a user operable member configured to move the movable member to allow at least the first movable electrical contact to move to the closed position.

9. The control device according to claim 8, wherein: The user operable member is further operable to move the movable member to move the first movable electrical contact to the open position.

10. The control device according to claim 8, further comprising a touch switch electrically connected to the solenoid control device and arranged so that the user-operable member causes a change in an output of the touch switch when operated by a user.

11. The control device according to claim 10, characterized in that: The solenoid control device monitors an output from a touch switch and supplies power to the electromechanical solenoid in the interrupting operating mode depending on the output, causing the armature to operate to move the first movable electrical contact from the closed position to the open position.

12. The control device of claim 1 further comprising at least one temperature sensor connected to the solenoid control device.

13. The control device according to claim 12, wherein: The solenoid control monitors a sensor output from the temperature sensor and, depending on the sensor output, supplies power to the electromechanical solenoid in the interrupting mode of operation such that the armature operates to move the first movable electrical contact from the closed position to the open position.

14. The control device according to claim 1, wherein: The solenoid control device is programmed or arranged to supply power to the electromechanical solenoid depending on an amount of time that has elapsed since closing the power supply circuit.

15. The control device of claim 1 further comprising a user input device operatively connected to the solenoid control device for changing the conditions under which the solenoid control device supplies power to the electromechanical solenoid.

16. The control device according to claim 1 further includes a second movable electrical contact and a second thermally sensitive actuator, wherein the second movable electrical contact cooperates with the corresponding second fixed electrical contact in the power supply circuit in the closed position of the second movable electrical contact, and the second movable electrical contact is separated from the second fixed electrical contact in the open position of the second movable electrical contact to interrupt the power supply circuit in the open position of the second movable electrical contact, and the second thermally sensitive actuator is capable of operating at an overheat temperature in an overheat operating mode to move the second movable electrical contact.

17. The control device of claim 1 further comprising a cordless electrical connector component.

18. The control device of claim 1 further comprising a dedicated power supply for supplying power to the electromechanical solenoid and solenoid control device.

19. The control device according to claim 1, wherein: The electromechanical solenoid and the solenoid control device are connected within the power supply circuit such that the electromechanical solenoid and the solenoid control device are supplied with power from the power supply circuit.

20. The control device of claim 1, further comprising an electronic processor configured to selectively supply power to the electromechanical solenoid.

21. A liquid heater device comprising a control device according to any of the preceding claims, and a heater and a resistive element, wherein the heater includes a first electric heating element, the first electric heating element includes a first pair of electrical terminals, the resistive element includes a second pair of electrical terminals, wherein the resistive element is electrically connected in series with the first electric heating element via an electrical connection between one of the first pair of electrical terminals and one of the second pair of electrical terminals, wherein the first electric heating element has a first resistance, the resistive element has a second resistance different from the first resistance, and wherein the electromechanical solenoid and the solenoid control device are electrically connected between one of the first pair of electrical terminals or the second pair of electrical terminals.

22. A liquid heating appliance comprising a vessel having a base heated by a heater, and a control device according to any one of claims 1 to 20, the control device being mounted below the heated base and arranged to control a power supply circuit to the heater.

23. A liquid heating appliance comprising a liquid flow heater comprising a heater and a liquid flow tube, and a control device according to any one of claims 1 to 20, the control device being arranged to control a power supply circuit to the heater.

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