DE102009046083A1 - Household appliance, in particular dishwasher - Google Patents

Abstract

The invention relates to a household appliance, in particular a dishwasher, at least comprising an appliance component (23, 24, 25) which can be supplied with electrical energy by means of a working line (30), in particular an electromagnetic valve, the appliance component (23, 24, 25) being provided in the working line (30) control element (26, 27, 28) arranged in a row can be controlled, which in at least one defect state remains permanently in a current-carrying state relating to the working line (30). According to the invention, a monitoring unit (32) is provided which, when the control element (26, 27, 28) is not activated, detects the electrical current flowing through the device component (23, 24, 25) and compares it with a threshold value in order to determine the defect state of the activation element (26, 27, 28).

Description

The invention relates to a domestic appliance, in particular a dishwasher, at least comprising a device component which can be supplied with electrical energy by means of a working line, in particular a solenoid valve, wherein the device component can be actuated by means of a control element arranged in series in the working line, that permanently in at least one defective state the working line relevant current-conducting state remains.

As is known, device components, such as an inlet valve, a regeneration valve and / or a water diverter, are connected in the rinsing fluid circuit of a dishwasher. These may comprise electromagnetically operable actuators or actuators, which are controllable by means of a control device. For this purpose, a control element is associated with each actuator, which is arranged in the circuit of the actuator and can be controlled by the control device. In the closed position of the drive element, the power supply to the actuator is interrupted, while in the open position of the drive element, the power supply to the actuator is released.

In the case of the inlet valve, the regeneration valve or the water diverter their actuators during a rinse cycle in total only over a period of a few minutes in operation. For reasons of reliability, however, these actuators are designed for continuous operation. Such a continuous operation of the actuator would result in an error case in which the triac is defective and therefore permanently conductive. In this case, the associated actuator would be permanently activated. The actuators are therefore far oversized for normal operation in which they are only briefly in operation.

The object of the invention is to provide a domestic appliance, in particular a dishwasher, in which the reliability is ensured in a simple, cost-effective manner.

According to the invention, the household appliance for detecting a defect state of the drive element to a monitoring unit. The monitoring unit can detect an electrical current in a working line of the device component with non-activated drive element and compare it with a threshold. On the basis of this comparison, the defect state of the drive element can be seen.

Thus, a function monitoring of the drive element, with a faulty drive element is recognizable. If such a defect state of the drive element is detected, appropriate measures can be taken to interrupt a power supply to the at least one device component. Since, according to the invention, a faulty actuator can be detected, therefore, the associated device component no longer has to be designed for continuous operation, as is the case without such a monitoring unit. With such a function monitoring, the monitoring unit can thus use a voltage or current measurement to detect whether the activation element is conductive or non-conductive. In this case, a monitoring unit can also be used to monitor a plurality of device components which, for example, are connected in series or in parallel.

The monitoring unit, in particular the current measuring device, may be connected in series in the working line to the drive element.

By way of example, the monitoring unit can have at least one voltage or current measuring device, for example a measuring shunt, or a current sensor with which the current flow through the actuator can be detected. The actually detected current and / or voltage level can be compared with the setpoint or threshold value for a functional and plausibility check. On the basis of the comparison, the error can then be detected. When using a measuring hunt, the voltage drop can be detected on a measuring resistor connected in the working line. Such a voltage drop is detected if current flows through the measuring resistor.

The drive element of the device component can be a control, for example a relay, a triac, a transistor or a mosfet, which can be switched between a current-conducting closed position and an open position. In contrast, the additional shutdown element may be a relay or a semiconductor.

In one embodiment, the control device - in addition to the drive element of the device component - be associated with an additional shutdown element. With the additional shutdown element, the control device can interrupt or release a power supply to the device component independently of a switching position of the drive element.

This may be particularly advantageous in the case of the above-mentioned error, in which the drive element of the device component is defective and is improperly permanently in a current-conducting closed position, in which it can no longer be actuated by the control device. In this case, the already mentioned would be disadvantageous Permanent activation of the device component result. Such continuous activation can be avoided by interrupting the power supply to the device component with the aid of the additional shutdown element. With the additional shutdown a permanent control is thus excluded. The device components or their actuators must therefore not be designed costly to this error.

The shut-off element can therefore be arranged in normal operation, that is, during a rinsing cycle, in an electrically conductive closed position and switched to its open position only when the drive element is defective.

Preferably, two or more device components are provided in the working line. Their control elements can be in signal connection with the control device. The device components may be connected in partial working lines of the working line parallel to each other, each device component may be assigned a control element. In this case, the plurality of device components may preferably be assigned a common switch-off element. The turn-off element can in particular be connected in series with the device components connected in parallel.

In addition, a pulse width modulation can be used in the power supply of the device component. As a result, regardless of network fluctuations, the electrical energy conducted to the device component can be kept constant.

For such a pulse width modulation, a rectifier can be connected in the circuit of the device component, which rectifies the mains voltage. At the same time, the control device can control the abovementioned shutdown element or the control element clocked in an adjustable duty cycle. The duty cycle may be in particular in a frequency range greater than 1000 Hz, preferably greater than audible frequencies, that is greater than 10 to 12 kHz. In case of a fluctuation of the mains voltage, the duty cycle of the shutdown element or the drive element can be varied such that an arithmetically averaged voltage is applied to the device component, which corresponds approximately to the voltage to which the device component is designed.

With the above-mentioned pulse width modulation thus the device component can be used regardless of the size of the mains voltage. For example, in the case of a mains voltage of 230 V (AC voltage) with direct rectification of the mains voltage, a DC voltage of 320 V can be generated. The DC voltage can be clocked by the shutdown element or the control element, for example, in a duty cycle of 50:50 as well as in a predetermined switching frequency. In this way, an arithmetically averaged DC voltage of 160 V is applied to the device component. With a changed mains voltage, the clock ratio can be changed in such a way that in turn an arithmetically averaged DC voltage of 160 V can be set on the device component. A device component designed for 160 V can thus be used for varying mains voltages.

In the following, two embodiments of the invention will be described with reference to the attached figures. Show it:

1 in a schematic block diagram, a dishwasher;

2 a circuit diagram according to the first embodiment; and

3 a circuit diagram according to the second embodiment.

In the 1 is roughly schematically as an exemplary embodiment of a household appliance, a dishwasher with a, a washing compartment limiting washing compartment 1 shown. In a sump 3 of the washing container 1 opens a fresh water supply 5 in which an inlet valve 7 is switched. The sump 3 is also via a recirculation line 9 with a circulation pump 13 in conjunction, which flushes the water through a water heater 14 as well as a water switch 15 either to spray arms 16 in the washing compartment of the washing container 1 or to a fleet store 17 leads, can be cached in the rinse liquid. The device components switched into the liquid circuit of the dishwasher, for example the inlet valve 7 , the circulation pump 13 or the water switch 15 , are via signal lines 19 from a controller 21 controllable.

On the basis of in the 2 The circuit diagram shows the power supply of the device components as well as their control. Exemplary are in the 2 the actuators or actuators 23 . 24 . 25 shown, with whose help the inlet valve 7 , the water switch 15 or other device components, such as a Regenerierventil not shown in detail, are actuated. The actors 23 . 24 . 25 are connected via a working line connected to the power supply network 30 supplied with electrical energy. The actors 23 . 24 . 25 are in parallel sub-lines 30a . 30b . 30c the work management 30 connected. Each of the actors 23 to 25 is in each case a drive element 26 . 27 . 28 connected in series.

The control elements 26 . 27 . 28 In the application shown, triacs are connected via the signal lines 19 by means of the control device 21 are controllable. In series with the three parallel actuators 23 to 25 is a shutdown element 29 in the work management 30 arranged, which also has a signal line 19 with the control device 21 is coupled. The shutdown element 29 is in its electrically conductive closed position during a purge cycle and, as described later, provides a second shutdown path.

In the to the sub-pipes 30a . 30b . 30c leading labor administration 30 is a measuring shunt 31 a monitoring device 32 connected. The shutdown element 29 may be a relay or a semiconductor.

With the monitoring device 32 can by the work management 30 or through the device components 23 . 24 . 25 flowing electrical current are detected. The detected current may be in an evaluation device of the monitoring unit 32 be compared with a threshold. If a current flow is detected which is greater than the predetermined threshold value, then this is regarded as the defect state of one of the three actuators, which is impermissibly current-conducting.

During a rinse cycle of the dishwasher are the actuators 23 . 24 . 25 temporarily in operation, that is with a certain pulse-pause ratio or only for a short time. The actors 23 . 24 . 25 may exemplarily have solenoid valve coils, the activation of a valve stem of the inlet valve 7 or the regeneration valve to move a valve lift. For this purpose, the control device controls 21 an example of the triac 26 on, causing the actor 23 is supplied with electrical energy. Subsequently, the triac 26 be re-energized, reducing the power supply to the actuator 23 is interrupted.

In device operation, for example, the triac 26 run away. In case of defective triac 26 this can be permanently in a current-conducting closed position, whereby the actuator 23 permanently energized. This error case is determined by means of the monitoring device 32 detected at the first measurement shunt 31 measured current is compared with the threshold value corresponding to a predetermined target current. The above-mentioned error case is detected due to a deviation of the actually measured current from this target current.

If an error occurs, the monitoring unit initiates 32 an interference signal to the control device 21 , The controller then opens 21 the shutdown element 29 , which reduces the power supply to the actuators 23 to 25 is interrupted. At the same time, the control device 21 a visual warning display 22 activate.

In the 3 a circuit diagram is shown according to the second embodiment, in which additionally a pulse width modulation is used, with the independent of mains fluctuations, the respective actuator 23 to 25 guided electrical voltage remains constant. For this purpose, the monitoring unit 32 a rectifier 33 upstream, with which the mains voltage is converted into a DC voltage. In addition, it is in parallel with the actuators 23 to 25 a freewheeling diode 34 intended to protect against overvoltage.

The shutdown element 29 is according to the 2 in normal operation is not constant in its closed position, but is clocked in a predetermined duty cycle and at a given switching frequency. The duty cycle is thereby by the controller 21 set such that an arithmetically averaged voltage is generated at the actuators 23 to 25 is applied and corresponds approximately to a voltage to which the respective actuators 23 to 25 are designed.

By way of example, at a first mains voltage of 230 V (AC voltage) by means of the rectifier 33 a DC voltage of 320 V are generated. At a duty cycle of the shutdown 29 of 50:50 can thus result in an arithmetically averaged DC voltage of 160 V, the at the actuators 23 . 24 . 25 is applied.

If now the dishwasher is applied to a power supply network with reduced or increased mains voltage, then the duty cycle starting from 50:50 can also be adjusted so that again sets an arithmetically averaged DC voltage of 160 V, the actuators 23 . 24 . 25 is applied.

LIST OF REFERENCE NUMBERS

1

rinse tank

3

sump

5

supply line

7

inlet valve

9

circulation line

13

circulating pump

14

water Heating

15

water points

16

spray arms

17

fleet memory

19

signal lines

21

control device

23, 24, 25

device components

26, 27, 28

Actuation

29

disconnection element

30

working line

30a, b, c

partial lines

31

Current measuring devices

32

monitoring device

33

rectifier

34

Freewheeling diode

Claims (15)

Domestic appliance, in particular a dishwasher, at least comprising one by means of a working line ( 30 ) can be supplied with electrical energy ( 23 . 24 . 25 ), in particular a solenoid valve, wherein the device component ( 23 . 24 . 25 ) by means of one in the working line ( 30 ) arranged in series control element ( 26 . 27 . 28 ) is controllable, in at least one defect state permanently in a working line ( 30 ) remains conductive state, characterized in that a monitoring unit ( 32 ) is provided, which is not activated in the control element ( 26 . 27 . 28 ) through the device component ( 23 . 24 . 25 ) is detected and compared with a threshold value for detecting the defect state of the drive element ( 26 . 27 . 28 ). Domestic appliance according to claim 1, characterized in that the monitoring unit ( 32 ) at least one voltage or current measuring device ( 31 ), by means of which the detected current is comparable to the threshold value, Domestic appliance according to claim 1 or 2, characterized in that the monitoring unit ( 32 ) in the labor administration ( 30 ) in series with the drive element ( 26 . 27 . 28 ) is switched. Domestic appliance according to one of the preceding claims, characterized in that the drive element ( 26 . 27 . 28 ) is a switching element, such as a relay, a triac, transistor or mosfet, and in one, by means of a control device ( 21 ) controlled state is conducting and is not current conducting in the non-energized state. Domestic appliance according to one of the preceding claims, characterized in that the control device ( 21 ) an additional shut-off element ( 29 ), which is independent of a switching position of the control element ( 26 . 27 . 28 ) a power supply to the device component ( 23 . 24 . 25 ) interrupts or releases. Domestic appliance according to claim 5, characterized in that in the presence of the defect state of the drive element ( 26 . 27 . 28 ) of the device component ( 23 . 24 . 25 ) the shutdown element ( 29 ) by means of the control device ( 21 ) is controllable in an open position, in which the power supply to the device component ( 23 . 24 . 25 ) is interrupted. Domestic appliance according to one of claims 5 or 6, characterized in that the switch-off element ( 29 ) is a relay or a semiconductor. Domestic appliance according to one of claims 4 to 7, characterized in that the control device ( 21 ) with at least two or more control elements ( 26 . 27 . 28 ) of device components ( 23 . 24 . 25 ) in signal connection ( 19 ). Domestic appliance according to one of the preceding claims, characterized in that a plurality of device components ( 23 . 24 . 25 ) parallel to each other in sub-work lines ( 30a . 30b . 30c ) are switched. Domestic appliance according to claim 8 or 9, characterized in that the at least two device components ( 23 . 24 . 25 ) a common shutdown element ( 29 ), in particular in series with the device components connected in parallel ( 23 . 24 . 25 ) is switched. Domestic appliance according to one of claims 5 to 10, characterized in that the switch-off element ( 29 ) is permanently in its closed position during normal operation of the household appliance. Domestic appliance according to one of the preceding claims, characterized in that in the power supply of the device component ( 23 . 24 . 25 ) a pulse width modulation takes place, with which independent of network fluctuations to the device component ( 23 . 24 . 25 ) kept electrical energy remains constant. Domestic appliance according to claim 12, characterized in that in the working line ( 30 ) of the device component ( 23 . 24 . 25 ) a rectifier ( 33 ) is switched, which generates a DC voltage from the mains voltage. Domestic appliance according to claim 13, characterized in that the control device ( 21 ) the shutdown element ( 29 ) or the control element ( 23 . 24 . 25 ) clocked with an adjustable duty cycle, which is in particular in a range greater than 1000 Hz, in particular greater than 10 KHz. Method for operating a domestic appliance, in particular a dishwasher, during which at least at least one time by means of a working line ( 30 ) electrical component device ( 23 . 24 . 25 ), in particular a solenoid valve, by means of a in the working line ( 30 ) arranged in series Control element ( 26 . 27 . 28 ), which in at least one defect state is permanently fed into a working line ( 30 ) current-conducting state remains, characterized in that when not activated drive element ( 26 . 27 . 28 ) generated by the device component ( 23 . 24 . 25 ) or work management ( 30 ) is detected and compared with a threshold value for detecting a defect state of the drive element ( 26 . 27 . 28 ).

Images