EP2553157B1

EP2553157B1 - Household appliance with stand-by wake-up system

Info

Publication number: EP2553157B1
Application number: EP11724454.1A
Authority: EP
Inventors: Mario Lippera; Gianluca Benedetto; Andrea Cesaroni; Gianluca Viola
Original assignee: Whirlpool EMEA SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2010-03-30
Filing date: 2011-03-30
Publication date: 2017-03-29
Anticipated expiration: 2031-03-30
Also published as: ITTO20100254A1; EP2553157A1; WO2011121550A1

Description

[TECHNICAL FIELD]

The present invention relates to the field of household appliances, and in particular to a household appliance according to the preamble of claim 1.
The invention also relates to methods for controlling household appliances, in particular with reference to energy consumption control and standby regulation.

[PRIOR ART]

The recent developments and lower costs of electronic components, along with the need of offering increasingly innovative products to customers, have led to the development of more and more sophisticated household appliances (e.g. washing machines, television sets, refrigerators, dishwashers).
Many household appliances on the market today utilise sensors which allow to detect the operating state of the appliance or some physical quantities useful or necessary for its operation. For example, some washing machines are provided with pressure switches that allow to detect the quantity of water in the tub in order to control the wash cycle.
The increasing use of on-board electronics has led household appliances to use much energy even when they are not operational, i.e. when they are not carrying out their main function, e.g. washing in the case of a dishwasher.
Aiming at reducing this energy consumption, a standby state is known to be used wherein no power is supplied to a part of the on-board electronics, in particular sensors and video or luminous interfaces.
In known household appliances, the exit from the standby state is possible in response to a user's action, e.g. pressing a power button.
In standby mode, the household appliances known in the art cannot therefore detect any physical quantities nor deduce what actions should be carried out as a consequence of such a detection, e.g. signalling a faulty condition of the appliance. This results in limited flexibility of use of these household appliances.
¶ EP 0 040 113 A1 shows a safety circuit for domestic appliances, in particular washing machines and dishwashers. In response to a control input from a level switch, a control logic permanently connected to a power supply switches on an electronic switch and switches a process control on to the power supply. The process control can actuate other switching processes through components, eg a discharge pump, of the domestic appliance.

[OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION]

It is one object of the present invention to overcome some of the above-described drawbacks of the prior art.
In particular, it is one object of the present invention to improve the flexibility of use of a household appliance without substantially increasing its energy consumption in standby mode.
It is another object of the present invention to prevent the effects of any malfunctions occurring when the household appliance is in standby.
These and other objects of the present invention are achieved through a household appliance incorporating the features set out in the appended claims, which are intended as an integral part of the present description.
One idea at the basis of the present invention is to provide the household appliance with an automatic function that wakes it up when an event is detected in standby mode. The household appliance is equipped with a sensor capable of detecting a physical quantity that can be associated with a fault, even when the appliance is in standby, and of automatically waking up the appliance.
In particular, this fault detection is carried out by detecting physical quantities associated with the operation of some components of the household appliance.
This solution ensures higher flexibility of use of the household appliance, since by monitoring physical quantities related to the operation of some components thereof it is possible to wake up the appliance in the event of a fault, so that the awakened appliance can warn the user and/or prevent any effects from occurring which might create discomfort for the user.
In a preferred embodiment, the household appliance is fitted with passive sensors (i.e. not requiring any electric supply), wherein the detection of an event causes an electric contact to close or to open, thereby waking up the appliance. This solution offers the advantage that it allows the household appliance to be automatically woken up without increasing the standby consumption.
As an alternative, active-element sensors may be used for detecting physical quantities; these sensors must be powered when the household appliance is in standby. At the cost of a very small increase in the standby energy consumption, this solution allows to detect physical quantities which would otherwise be hardly detectable (or not detectable at all) through non-powered electromechanical actuators, thus improving the flexibility of use of the household appliance.
Further objects and advantages of the present invention will become more apparent from the following description and from the annexed drawings.

[BRIEF DESCRIPTION OF THE DRAWINGS]

Some preferred and advantageous embodiments will now be described by way of non-limiting example with reference to the annexed drawings, wherein:

Fig. 1 shows a laundry washing machine according to the present invention.
Fig. 2 shows a functional block diagram of the machine of Fig. 1.
Fig. 3 shows an embodiment of the block 12 of Fig. 2.
Fig. 4 shows an embodiment of the block 14 of Fig. 2.
Fig. 5 shows a functional block diagram of the machine 1 which is alternative to the one of Fig. 2.
Fig. 6 is a sectional view of a dishwasher according to the present invention.

The drawings show different aspects and embodiments of the present invention and, where appropriate, similar structures, components, materials and/or elements in the various drawings are designated by the same reference numerals.

[DETAILED DESCRIPTION OF THE INVENTION]

Fig. 1 shows a sectional view of a front-loading laundry washing machine 1.
Through a load opening, the laundry to be washed is inserted into a drum 3 positioned inside the wash tub 2.
For washing the laundry, a solution of water and detergents is supplied into the tub 2 through a duct (not shown in the drawing); an electric motor then drives the drum 3, which rotates about the horizontal axis 4.
Through holes 30 in the drum 3, the laundry items get imbibed and are washed. As known, laundry washing requires several steps in which water (or water plus detergents) is supplied into the tub and then drained.
The washing machine 1 therefore comprises a drain duct 5 communicating with the tub 2, in which duct the wash liquid can collect.
A control unit 6 of the machine 1 controls the drain pump 7, arranged along the drain duct 5, so as to drain the liquids contained in the tub.
The control unit 6 comprises a microcontroller whose task is to control the operation of the household appliance.
In order to allow the control unit 6 to control the operation of the machine 1 (e.g. to decide when the pump 6 must be turned on or when the drum revolution speed must be changed), the machine is equipped with various sensors, among which a sensor 8 capable of detecting the level of the wash liquids accumulated in the tub 2.
In one embodiment, the sensor 8 is a mechanical pressure switch, i.e. a device acting as a switch, which can therefore take two states (open or closed) depending on the pressure exerted by the liquids contained in the tub. This type of pressure switch requires no electric supply to operate, since the opening or closing of the contact depend exclusively on the pressure exerted by the wash liquids onto a movable or deformable surface of the pressure switch itself.
As an alternative, active sensors such as linear pressure switches may be used. Although their power consumption is very low, these latter sensors must be supplied with electric energy to generate a (continuous or periodic) signal having at least one parameter (e.g. amplitude or frequency) dependent on the quantity of liquid in the tub.
In a further alternative, the sensor 8 comprises switching means, such as a mechanical pressure switch, and signal generating means, such as a linear pressure switch.
In general, when the sensor 8 detects that the liquids contained in the tub exceed a certain quantity, it then changes state, thus allowing for the detection of an event which can be classified as "liquids in tub exceeding a certain quantity".
In the following example, described with reference to Fig. 2, the pressure switch is schematised as a switch 8 that closes when the level of the liquids in the tub exceeds a certain quantity.
Fig. 2 illustrates a portion of interest of the circuit diagram of the washing machine 1. It is understood that the washing machine 1 also comprises other electric and electronic components (like, for example, the user interface and the electric loads) not shown in the diagram of Fig. 2, but connected to or associated with elements of Fig. 1.
The machine 1 comprises a power supply 200 receiving power from an alternating power line 201, shown herein as phase L and neutral N (e.g. a 230V @ 50Hz or 110V @ 60Hz mains voltage), and outputs a 12V direct voltage Vdc. The number and values of the output voltages supplied by the power supply 200 is not to be considered as limiting for the purposes of the present invention.
The control unit 6 is powered by a direct voltage (e.g. 3.3V) obtained from the 12V Vdc through a suitable voltage regulator 9.
Downstream of the power supply 200 there is a standby switch 10 controlled by the control unit 6. The standby switch 10 may be an electromechanical switch (e.g. a relay) or an electronic switch (e.g. a triac or an SCR).
When the washing machine 1 enters the standby state, the control unit 6 opens the standby switch 10 to stop the power supply to all devices powered by Vdc voltage taken downstream of the standby switch 10. At the same time, the control unit 6 operates some (electromechanical or electronic) switches to disconnect the machine's loads which would otherwise remain connected to the alternating power mains, e.g. the motor or the pump or the heating resistor.
Other standby solutions may be adopted as well, as will be shown with reference to Fig. 5.
Referring back to the example of Fig. 2, a block 11 for detecting the change of state of the pressure switch 8 and a block 12 for detecting when the power button 13 is pressed by the user are connected to a block 14 which allows to detect one of the two "pressure switch closed" and "power button pressed" events. The output OUT 14 of the block 14 is received at the wakeup input 60 of the control unit 6. When the user presses the power button, or when the pressure switch signals the presence of a certain quantity of liquids in the tub, the output signal of the block 14 is set to an active level, thereby indicating the necessity of waking up the washing machine 1.
In response to the activation of said signal at the wake-up input 60, the control unit 6 closes the standby switch 10 so as to supply current again to those devices which received no power in standby mode.
Fig. 3 shows an embodiment of the block 12 of Fig. 2; said block comprises a resistor R1 and the power button 13 connected in series. The resistor R1 is connected to the power voltage, whereas the button is connected to ground.
When the user presses the power button 13, the output OUT12 of the block 12, between the resistor R1 and the button 13, is grounded and therefore switches from the high electric level (taken in standby mode) to the low electric level (taken at power on).
In one embodiment, the block 11 is designed substantially like the block 12, with the pressure switch 8 performing the same function as the button 13. When the pressure switch detects a quantity of liquids exceeding a certain threshold, it closes and brings the output OUT11 of the block 11 low.
The outputs OUT11 and OUT 12 of the blocks 11 and 12 are connected to the input of the block 14.
Fig. 4 shows one embodiment of the block 14. In this embodiment, the inputs IN11 and IN 12, which receive the signals from the outputs OUT11 and OUT12 of the blocks 11 and 12, respectively, are connected to the output OUT 14 through a respective diode (D11 and D12) with the anode connected to the output.
The output OUT14 is hung to the power voltage through a resistor R2, and therefore it remains high as long as both the inputs IN1 and IN2 are high; instead, it is low in all other cases.
The output OUT 14 is connected to the wake-up input 60 of the control unit 6, which wakes up when a low signal is present at the input, indicating that at least one event (of the "power button pressed" and "pressure switch closed" events) has been detected.
The output OUT11 of the block 11, i.e. the signal that carries the information about the detection of the event associated with the change of state of the pressure switch, is also supplied to a second input 61 of the control unit 6.
The input 61 is read when the machine 1 is running and its operation must be checked also as a function of the quantity of liquids contained in the tub.
The example of Fig. 5 shows a variant of the circuit diagram of Fig. 2, wherein the control unit 6 takes power downstream of the standby switch 10. In this example, when the household appliance enters the standby mode, the control unit 6 cuts power to itself as well, and therefore it can act upon the switch only to open it, not to close it.
For this reason, the output of the block 14 is not sent to the control unit 6, which would not be able to activate itself; instead, it is used for controlling the standby switch 10. In this example, pressing the button 13 or closing the pressure switch 8 will directly cause the standby switch 10 to close, thereby supplying current again to the whole appliance, which will then wake up.
It is apparent from the above that the washing machine 1 can wake up from the standby state both when the user presses the power button and automatically when the pressure switch closes. This makes it possible to warn the user and/or to prevent any effects which might create discomfort for the user, e.g. flooding. Let us consider, for example, a case in which a solenoid valve fails and the washing machine starts taking in water while in the standby state. When the water in the tub exceeds a certain quantity, the pressure switch closes and the standby switch 10 will then close automatically, thus causing the machine 1 to wake up; at the same time, the control unit 6 detects the presence of water from the signal at the input 61 and can therefore turn on the pump 7 to drain away the water, thereby preventing it from exiting the machine and flooding the surrounding area. It is clear the many changes may be made to the above-described embodiments by a man skilled in the art wanting to design a household appliance with an automatic standby wake-up function, without however departing from the protection scope of the present invention as set out in the appended claims.
For example, the various circuit blocks may be combined and integrated differently to form new blocks performing the same functions.
The standby switch may be located in various points of the power line so as to have the standby function operate in different ways. For example, in one embodiment the standby switch may be arranged upstream of the power supply 200, so that it can directly act upon an input phase of the latter (e.g. the phase L of Fig. 2); in standby mode the power supply 200 will thus be completely disconnected, resulting in lower standby consumptions.
In this embodiment, the standby switch is preferably controlled directly by the switch 13 or by the sensor that detects the fault.
The sensor that remains operational in standby mode may be of various types; the example of the pressure switch is in fact a preferred but non-limiting example of the present invention.
For example, the sensor kept operational in standby mode may be a litre-counter sensor normally used by washing machines and dishwashers to regulate the quantity of water taken in by the household appliance. The litre-counter sensor is, for example, a sensor that generates a signal consisting of a sequence of pulses at a frequency proportional to the quantity of water flowing through the litre-counter sensor. In one embodiment, the litre-counter sensor comprises an impeller arranged inside a drain duct. The impeller is rotated by the water being supplied. By counting the impeller revolutions, e.g. by means of an encoder, it is possible to calculate the litres of water supplied.
In one embodiment, if the litre-counter sensor detects any water supply when the machine is in standby mode, then it will operate the standby switch (whether directly or through the control unit) in order to wake up the household appliance.
The invention, described herein with reference to a washing machine, is also applicable to other types of household appliances, e.g. a dishwasher or an oven.
Fig. 6 shows a sectional view of a dishwasher 600 according to the present invention.
The dishwasher 600 comprises a wash chamber 601 in which sprayers 602 spray water onto racks 603 housing crockery to be washed.
Water is supplied to the sprayers through a hydraulic circuit 604 that supplies water to the sprayers 602 and crockery racks 603. The circuit 604 comprises two valves 605 which, in one embodiment, are integrated into a single component called alternating valve.
The water supplied to the wash chamber is heated by the resistor 606 and is then delivered under pressure to the sprayers by the wash pump 607.
The pump 608 controls the draining of the liquids contained in the wash chamber 601.
In order to control the various wash steps, the dishwasher 600 is equipped with a pressure switch 609 connected to a pressure take-off 610 in the sump 611 of the wash chamber 601. The pressure switch 609 is also connected at the top to the electronic control represented by the block 612.
The dishwasher may, for example, suffer a failure like the one previously described with reference to a washing machine, wherein a faulty solenoid valve causes water to (unexpectedly) enter the machine, which water must be drained in order to prevent flooding. It is therefore apparent that a man skilled in the art may use the circuit diagrams described above with reference to a washing machine and apply them to a dishwasher to control the drain pump as the pressure switch closes.
In an oven, according to an example useful for understanding the invention, there may be a sensor that detects a voltage drop and allows waking up the household appliance as soon as the voltage returns to an optimal value. A prolonged voltage drop or blackout could, in fact, reset the internal clock and jeopardise the proper operation of delayed-start cooking programs (set by the user prior to the voltage drop). When the sensor detects that voltage has been restored, it will then wake up the oven, which will inform the user, e.g. by sensing a message like an SMS (Short Message System) message.
It is also apparent that the actions that the household appliance may take after waking up may be of various kinds and variably dependent on the physical quantity and/or on the event detected in standby. For example, the household appliance may simply report the fault by turning on warning lights, by activating audible alarms, or by sending signals to remote service centres (e.g. through a telecommunication network connection).

Claims

A household appliance comprising:
A) a standby switch (10) adapted to take a first standby position, in which it breaks the current flow on a power supply line in order to place the household appliance into standby mode, and a second position, in which the household appliance is operational,

B) a sensor (8) adapted to detect an event which may be associated with a fault of the household appliance,

C) wake-up means (6,11,14) operating when the household appliance is in standby and adapted to bring said standby switch (10) into said second position when said sensor (8) detects said event,

D)a control unit (6) adapted to bring said standby switch (10) into said first position,

E) a drain pump (7) controlled by said control unit (6),

F) a power supply (200) receiving power from an alternating power line (201),

G) a voltage regulator (9), the control unit (6) being powered through said voltage regulator (9),
wherein said wake-up means comprise said control unit (6), said control unit (6) being operationally connected to said sensor (8) to receive a signal generated by said sensor (8) about the detection of said event,
characterized in that
said control unit (6) is supplied by said power supply line upstream of said standby switch (10) when the household appliance is in standby and is adapted to switch said standby switch (10) from said first position to said second position.
A household appliance according to claim 1, wherein said control unit (6) is not powered in standby mode, wherein said sensor (8) is adapted to generate a wake-up signal when it detects said event, and wherein said standby switch (10) is operationally connected to said sensor (8) and is adapted to switch itself from said first position to said second position when it receives said wake-up signal.
A household appliance according to any one of the preceding claims, wherein said sensor (8) is a mechanical device capable of switching between two positions, corresponding to said event being detected or not, without needing any electric power.
A household appliance according to any one of the preceding claims, wherein said sensor is a pressure switch.
A household appliance according to any one of the preceding claims, wherein said household appliance is a dishwasher or a washing machine.