EP2407078B1 - Dishwasher - Google Patents

Description

The invention relates to a dishwasher, in particular a household dishwasher, with at least one activatable circulating pump for applying liquid to the items to be cleaned, at least one activatable drain pump for conveying out a minimum amount of liquid of an operating liquid amount from a pump bowl of the dishwasher, and a filter unit for retaining in the liquid-containing dirt particles from the circulation pump.

The DE 10 2008 020 475 A1 shows a method for carrying out a washing program in which washing liquid is circulated from a washing container to spraying devices by means of a circulating pump during individual program sections and is removed from the washing container at the end of the washing program by means of an emptying device. A partial exchange of the rinsing liquid located in the rinsing container takes place, the emptying device and the circulating pump being operated alternately several times during the partial exchange in order to limit the amount of liquid removed from the rinsing container as precisely as possible.

The DE 10 2008 055 022 A1 describes a method for pumping out a liquid from a water-carrying household appliance, during which water is at least temporarily pumped out of the water-conducting household appliance by operating a drain pump and at least temporarily water is circulated by operating a circulation pump. It is provided that the speed of the circulation pump is reduced from a maximum speed to at least a minimum speed, essentially without pressure surge, before the drain pump is started up.

The DE 100 14 871 A1 shows a method that allows the detection of residual water in the rinse tank or collection pot at the end of water-bearing program sections. For this purpose, at least one temperature sensor device is used, which is arranged in a defined height in the rinsing container or collection pot of the household appliance. Existing residual water is drained over the Temperature curve determined on the sensor device and evaluated by the device electronics. In doing so, an inadmissibly high remaining amount of residual rinsing liquid can be recognized after the rinsing liquor has been pumped out and possible measures can be taken to prevent carryover of lye.

The US 2005/0245413 A1 describes a dishwasher with a washing chamber, a washing pump driven by an electric motor for pumping washing water from a washing water tank into the washing chamber and a control unit for controlling the washing cycle of the machine. The control unit is able to detect at least one working parameter of the electric motor of the pump, this parameter being linked to one or more parameters of the washing cycle and being used to control such a cycle.

Dishwashers have a filter unit, which can be constructed from a multi-stage filter, such as a coarse sieve, a fine sieve and a microsieve, with which dirt particles, which have been loosened by the application of liquid to the items to be cleaned, can be separated from the circulated liquid, in order to do so to prevent re-soiling of the wash ware. As a result of heavy use, a filter cake can form on individual sieves of the filter unit, which clogs the filter unit. Furthermore, frequent operation of a dishwasher at low temperatures, i.e. the circulated liquid is reduced to e.g. Max. Heated to 45 ° C, fat deposits form on water-carrying parts of the dishwasher, e.g. the filter unit with its filters, with the result that the filter unit is also blocked by the fat deposit. With such a clogged filter unit, it is not possible to continue a washing program because the blocked filter unit means that the dishwasher cannot be pumped completely empty by starting up the drain pump, which means that when the dishwasher is started up again, the remaining one in the dishwasher becomes dirty Liquid mixed with the newly filled liquid and thus negatively affects the cleaning performance of the dishwasher.

It is an object of the invention to remedy this.

This object is achieved by a method for operating a dishwasher with the features of claim 1.

It is provided that after activating and deactivating the drain pump in order to convey out the minimum amount of liquid, the circulation pump can be activated, the operating parameters of which can be evaluated for a remaining amount of liquid remaining in the dishwasher. It is thus possible in a surprisingly simple way, without additional components, such as sensors or impeller counters, to determine whether the liquid circulated during the operation of the circulating pump, with which the items to be cleaned have been treated, after the completion of a sub-program step of a washing program by commissioning the drain pump in Was conveyed out substantially or only partially or not. This takes advantage of the fact that it can be determined by starting up the circulation pump and evaluating its operating parameters whether or not a residual amount of liquid has remained in the dishwasher. The amount of residual liquid is a quantity of liquid remaining in the dishwasher, for example if a clogged filter prevents pumping. In the case of a complete pumping out, the size of the minimum amount of liquid to be pumped out can essentially correspond to the size of an amount of operating liquid that is required to clean washware. However, the minimum amount of liquid to be pumped out has a minimum size, for example 0.1 to 1 liter, such as, for example, about 0.5 liter, in order to ensure that the resulting minimum amount of liquid can be reliably detected by evaluating the operating parameters. In this case, it is a partial drain, in which the dishwasher is not completely emptied. The amount of residual liquid thus essentially corresponds to the amount of operating liquid reduced by the minimum amount of liquid to be pumped out, whereby liquid residues adhering in the washing container or residual amounts of water remaining in the piping system of the dishwasher due to the design and deviations due to component tolerances are taken into account. The conveying out of a quantity of liquid from a pump pot of a dishwasher is understood to mean that this liquid is conveyed into an on-site sewage disposal system or at least partially in a liquid storage device, such as a tank, for a later one Reuse is stored, wherein the liquid reservoir can be assigned to the dishwasher and can be arranged within the housing of the dishwasher.

It is preferably provided that the electrical current consumption of a circulating pump motor driving the circulating pump can be detected and evaluated as the operating parameter of the circulating pump. The fact that the electrical current consumption of a circulating pump motor is increased by conveying a quantity of liquid in the dishwasher is thus exploited, while when the dishwasher is pumped completely empty, the circulating pump motor has a reduced current consumption, since only air can be conveyed. It is thus surprisingly simple to determine whether an undesired amount of residual liquid has remained in the dishwasher by comparing a detected current consumption during operation of the circulating pump after a pumping process by the drain pump and comparing it with a stored reference value.

It is preferably provided that the circulation pump motor is designed as a BLAC or BLDC motor, i.e. as a brushless DC or AC motor with an electronic commutation. Due to the electronic commutation, a connection between the electrical current consumption and the amount of liquid conveyed can be established particularly easily.

It is further provided that the circulation pump can be activated for a predetermined period of time. In a control electronics of the dishwasher, a sub-step of a washing program is provided, according to which the circulation pump is put into operation for a predetermined period of time, for example 0.3 to 10 seconds, after a pumping-out process has taken place, in order to check whether there is a residual amount of liquid in the dishwasher or not. This reduces the noise level due to the commissioning of the circulation pump due to its short-term character.

Since a filter cake clogging the filter unit or corresponding fat deposits build up slowly, it is not necessary to check whether the filter unit is clogged each time the dishwasher is started. However, it is preferably provided that after each removal of liquid, ie after each time a pumping process is carried out, the circulation pump can be activated, the operating parameters of the circulation pump being evaluable each time for a quantity of residual liquid being pumped. This allows a blockage of the filter unit to be recognized at an early stage by a filter cake or fat deposit and, if necessary, countermeasures to be provided.

It is provided that an optical and / or acoustic error signal can be generated if the amount of residual liquid is exceeded. This makes it possible in a simple manner to notify an operator that the filter unit is clogged and / or that a contaminated residual amount of liquid has remained in the dishwasher. An optical error signal can be displayed, for example, by a corresponding signal lamp on a control panel of the dishwasher.

Finally, it is provided that a cleaning program for cleaning the filter unit can be carried out if the amount of residual liquid is exceeded. Such a cleaning program can be triggered manually by an operator on the basis of an optical or acoustic signal, for example by means of a corresponding selection button on the control panel of the dishwasher, or such a cleaning program is automatically inserted into a washing program sequence with several sub-program steps without an operator being involved got to. The cleaning program for cleaning the filter unit can provide for the operation of the circulation pump and / or drain pump, pressure fluctuations being generated by means of speed fluctuations in order to clean the filter unit and / or operation with a change in direction of rotation if the drain pump or circulation pump is designed for this. Furthermore, the cleaning program for cleaning the filter unit can provide, for example, refilling the dishwasher and eliminating fat deposits on the filter unit by heating the liquid to temperatures of, for example, 60-80 ° C. It can also be provided to operate the circulation pump motor at a reduced speed, so that heating of the items to be cleaned is avoided by exposure to heated liquid, since due to the low speed and the low pressure, the heated liquid is released from the spray devices to act on the Washware emerges, that it does not come into contact with the items to be cleaned. Finally, the addition of cleaning agent may also be provided for cleaning the filter unit.

According to the invention, a method for operating a dishwasher, in particular a domestic dishwasher, is proposed, during which liquid is to be cleaned at least temporarily with an activated circulation pump, and during which at least temporarily an activated suds pump is used to supply a minimum amount of operating fluid from a pump pot Dishwasher is conveyed out, and furthermore dirt particles contained in the liquid are kept away from the circulating pump by means of a filter unit, whereby according to the invention it is provided that after activating and deactivating the drain pump to convey out the minimum quantity of liquid, the circulating pump is activated, the operating parameters of which relate to a residual quantity of liquid remaining in the dishwasher be evaluated and if the amount of residual liquid is exceeded, an optical and / or acoustic signal ch error signal is generated and / or a cleaning program for cleaning the filter unit is carried out if the amount of residual liquid is exceeded.

Advantageous developments of the method are specified in the subclaims.

The invention is explained below with reference to a drawing. It shows the
Figure 1 is a schematic representation of an embodiment of a dishwasher.

Shown as an exemplary embodiment of a dishwasher is a household dishwasher GS, which has a washing container SB in which items to be cleaned (not shown) can be stored on pull-out crockery baskets (not shown). Spray arms (not shown) are provided in the washing compartment SB to act on the items to be washed stored in the crockery baskets, which are connected to a circulation pump UP in a liquid-conducting manner via a spray arm feed line SZ. During the operation of the household dishwasher GS, ie during the Carrying out a washing program having several sub-program steps, the circulation pump UP is driven by a circulation pump motor UPM, the liquid dripping from the items to be washed collecting in a pump pot PT in the bottom region of the washing container SB in order to be fed back to the circulation pump UP, which for this purpose is liquid-conducting with the Pump pot PT is connected. In order to separate dirt particles contained in the liquid, which have been detached from the wash items, for example, from the liquid and to retain them from the circulation pump UP, in the Pump pot PT a filter unit FE is provided, which can be formed for example from a coarse, fine and microfilter.

Furthermore, a heating device (not shown) is provided for heating the liquid circulated by means of the circulation pump UP, for example to increase the cleaning action of the water mixed with detergent and / or rinse aid.

In order to empty the household dishwasher GS after the completion of a sub-program step of a washing program, during which the items to be cleaned are acted upon by liquid circulated by means of the circulating pump, possibly with the addition of detergent and / or rinse aid, a drain pump LP is also provided, which is operated by a drain pump motor LPM is driven and allows liquid to be pumped out of the pump pot PT of the household dishwasher GS by means of an emptying line EL into an in-house wastewater disposal network. For this purpose, the pump pot PT is connected to the drain pump LP in a liquid-conducting manner. To control the circulation pump UP and the drain pump LP or the circulation pump motor UPM and the drain pump motor LPM, control electronics SM are provided which are connected to the motors mentioned via control lines (not shown). In the present exemplary embodiment, the circulation pump motor UPM as well as the drain motor LPM is an electronically commutated brushless AC motor (BLAC), in which, due to the electronic commutation, the detection of the current consumption by means of the control electronics SM is particularly simple.

During the operation of the UP circulation pump with the UPM circulation pump motor running, the rinsing liquor passes through a sieve surface, for example a jacket surface of, for example, a cylindrical filter of the filter unit FE, in order to be subsequently sucked in by the UP circulation pump, while the liquor pump LP does not pass the liquid through the Shell surface of the sieve of the filter unit FE occurs. This makes it possible to remove a filter cake that forms on the inner surface of the filter unit FE during a pumping process by starting up the drain pump LP and thus to effect a cleaning of the sieve surface of the filter unit FE.

Nevertheless, the filter unit FE can become blocked, for example due to the formation of fat deposits on the filter unit FE due to operation of the dishwasher at low operating temperatures, for example in the range of 45 °, to which the circulated liquid is maximally heated during the washing program step.

If the filter unit FE is blocked and the household dishwasher GS is to be emptied by starting up the drain pump LP, the household dishwasher GS cannot be completely emptied, since the blocked filter unit FE causes a residual amount of liquid between the filter unit FE and the circulation pump UP remains in the pipe system, which also includes the spray arm feeder SZ, for example. This amount of residual liquid can negatively influence the cleaning performance due to the dirt particles it contains when the household dishwasher GS is started up again, since these dirt particles mix with the fresh water added in the amount of residual liquid. Because of the blocked filter unit FE, the intended use of the household dishwasher GS is not possible.

In order to determine whether the filter unit FE is blocked, for example by grease deposits, it is therefore provided that after a pumping-down process in which the drain pump LP, by starting up the drain pump motor LPM, a liquid quantity, that is to say a minimum liquid quantity with a detectable minimum size, is discharged into a household discharge line EL Wastewater disposal network promotes to put the circulation pump UP into operation by activating the circulation pump motor UPM, for example for a period of 0.3-10 seconds. The amount of liquid can be a pumping amount that is smaller than an operating liquid amount if it is a partial pumping, or the pumping amount corresponds to the operating liquid amount if it is a complete pumping. Such a control sequence can be stored, for example, in the control electronics SM, in which a large number of washing programs with a large number of sub-program steps are stored. On the basis of the detected current consumption of the circulation pump motor UPM during this period, it can be determined, based on the relationship between the current consumption of the circulation pump motor UPM and the quantity of liquid conveyed, whether a Residual liquid quantity due to a blocked filter unit FE remained in the household dishwasher GS despite the start-up of the drain pump LP. For this purpose, the control electronics SM compare the current consumption totaled during the time period with a stored reference value.

This check as to whether the filter unit FE is blocked or not can be carried out every time the liquid is pumped out by starting up the drain pump LP or in certain alternative intervals with a longer interval duration.

If it has been determined by means of the control electronics SM that the electrical current consumption of the circulation pump motor UPM exceeds a limit value, an optical and / or acoustic error signal is generated upon the determination that a minimum amount of liquid has remained in the household dishwasher GS, the optical error signal, for example can be displayed by means of a signal lamp (not shown) on a control panel (not shown) of the household dishwasher GS.

An operator can then manually clean the filter unit FE so as to remove the blockage of the filter unit FE. The household dishwasher GS can also have a selection button for a cleaning program for cleaning the filter unit on the control panel. In this cleaning program for cleaning the filter unit FE, for example to remove fat deposits in the filter unit FE, the residual liquid quantity remaining in the household dishwasher GS can be circulated as much as possible through the blocked filter unit FE by starting up the circulation pump UP and by means of a heating device Heat temperatures of at least 60 ° C in order to loosen the fat deposits on the filter unit FE and then convey the liquid with the dissolved fats into the household waste water disposal network by starting up the drain pump LP through the drain line EL. The degreasing of the filter unit FE can be improved by adding cleaning agents. Furthermore, the cleaning program for cleaning the filter unit FE can provide an operating mode of the circulation pump UP and the drain pump LP, in which the UPM and the drain pump motor LPM are controlled by appropriate control Pressure peaks to release the blockage of the filter unit FE were generated and possibly an operation against the normal operating direction.

Alternatively, when a residual liquid quantity is detected in the dishwasher after a pumping process by means of the drain pump LP, it can be provided that the control electronics SM automatically inserts such a cleaning program for cleaning the filter unit FE into a washing program sequence with a plurality of sub-program steps, so that an intervention by one Operator is not necessary.

Reference list

EL

Drain line

FE

Filter unit

GS

dishwasher

LP

Drain pump

LPM

Drain pump motor

SB

Rinsing tank

SM

Control electronics

SZ

Spray arm feed line

PT

Pump pot

UP

Circulation pump

UPM

Circulation pump motor

Claims (5)

1. Method for operating a dishwasher, in particular a household dishwasher, during which liquid is applied to items to be washed by way of an activated recirculating pump (UP), at least for a time, and during which a minimum quantity of liquid of a quantity of operating liquid is conveyed out of a sump (PT) of the dishwasher (GS) by means of an activated drain pump (LP), at least for a time, wherein dirt particles contained in the liquid are kept away from the recirculating pump (UP) by means of a filter unit (FE) and, after the drain pump (LP) for conveying out the minimum quantity of liquid has been activated and deactivated, the recirculating pump (UP) is activated, the operating parameters of which are evaluated for a residual quantity of liquid remaining in the dishwasher (GS), wherein an optical and/or acoustic error signal is generated in response to the residual quantity of liquid being exceeded and/or wherein a cleaning program for cleaning the filter unit (FE) is performed in response to the residual quantity of liquid being exceeded, wherein the activation of the recirculating pump (UP) is a substep of a wash program provided in a control electronics unit of the dishwasher, and wherein the recirculating pump (UP) is brought into operation for a predetermined period of time according to the wash program after a pumping-out procedure has taken place, in order to check whether or not the residual quantity of liquid is situated in the dishwasher.
2. Method according to claim 1, characterised in that the electrical power consumption of a recirculating pump motor (UPM) driving the recirculating pump (UP) is captured and evaluated as an operating parameter of the recirculating pump (UP).
3. Method according to claim 1 or 2, characterised in that a BLAC or BLDC motor is used as the recirculating pump motor (UPM).
4. Method according to claim 1, 2 or 3, characterised in that the recirculating pump (UP) is activated for a predetermined period of time.
5. Method according to one of claims 1 to 4, characterised in that the recirculating pump is activated after liquid has been conveyed out, wherein, each time, operating parameters of the recirculating pump (UP) are evaluated for a residual quantity of liquid.

Images