WASHING METHOD HAVING DISCONTINUOUS DISPENSING OF WASHING LIQUOR, AND DISHWASHER

Abstract

In a method for operating a dishwasher, a loosening phase is controlled by a control apparatus of the dishwasher for loosening soiling adhering to items to be washed in a dishwasher cavity by means of a washing liquor which is dispensed by a spray apparatus arranged in or on the dishwasher cavity. During the loosening phase, a circulating pump designed to deliver the washing liquor from a pump sump of the dishwasher cavity to the spray apparatus is operated for discontinuous dispensing of the washing liquor from the spray apparatus. The soiling is rinsed off in a rinsing-off phase, with at least 75% of the washing liquor from the loosening phase being reused during the rinsing-off phase.

Description

The present invention relates to a method for operating a dishwasher, also a computer program product and finally a dishwasher.

EP 1 362 545 B1 discloses a method for operating a dishwasher having a first program section with heated washing liquid and followed by a second program section with cold washing liquid. In the second program section a circulation is interrupted several times by repeatedly switching a circulating pump on and off.

EP 0 659 381 A1 discloses a method for operating a dishwasher, having a rinsing-off phase and/or a washing phase. In each of these phases, water is introduced into a sump of the dishwasher up to a static level. A pump has a suction opening below the static level and can be operated in order to spray water out of spray nozzles. The pump is repeatedly switched on until a water level in the sump has dropped to a level of the suction opening of the pump, and switched off. After each of these phases a drainage pump is then switched on, in order to drain the water out of the sump. In this manner, a quantity of water required for each phase can be reduced to 3 liters, for example. As a result, it is possible to add a reduced quantity of detergent to the water.

Against this background, an object of the present invention is to provide an improved method for operating a dishwasher and/or a dishwasher designed for carrying out the improved method. Particular attention is paid to increasing the efficiency of the method.

Accordingly, a method for operating a dishwasher, in particular a household dishwasher, is proposed. The dishwasher comprises a dishwasher cavity for receiving items to be washed, at least one spray apparatus, a circulating pump and a control apparatus. The spray apparatus is arranged in and/or on the dishwasher cavity in order to dispense washing liquor onto the items to be washed. The circulating pump is designed to deliver washing liquor from a pump sump of the dishwasher cavity to the at least one spray apparatus. The method comprises at least one loosening phase and one rinsing-off phase. The loosening phase and/or the rinsing-off phase are controlled by the control apparatus. The loosening phase is suitable for loosening, by means of the washing liquor, soiling adhering to the items to be washed.

During the loosening phase, the circulating pump is operated for discontinuous dispensing of the washing liquor from the at least one spray apparatus. The rinsing-off phase is suitable for rinsing off the soiling. At least 75% of the washing liquor from the loosening phase is reused during the rinsing-off phase.

The method proposed above contains the loosening phase. During the loosening phase, washing liquor is dispensed discontinuously onto the items to be washed. Thus a detergent contained in the washing liquor is applied to soiling adhering to the items to be washed. This results in the soiling swelling and becoming loosened. Subsequently in the rinsing-off phase, the loosened soiling can be rinsed off using a small amount of energy. As a result, a desired cleaning result is achieved by an efficient method.

The washing liquor from the loosening phase is largely reused during the rinsing-off phase. This reduces the water consumption of an entire washing program and improves the efficiency of the method.

Preferably, it is provided to reuse the entire washing liquor from the loosening phase during the rinsing-off phase. This further increases the efficiency of the method.

A washing program can contain, for example, different sub-program steps, such as for example a pre-washing, a cleaning or main washing, a rinsing with rinse aid and/or a drying. Different washing programs differ, for example, in a sequence and/or type of sub-program steps and in different operating parameters, such as for example a duration and/or a washing liquor temperature of one or more sub-program steps.

According to a further embodiment, it can be provided that the loosening phase is a pre-washing or a part of the pre-washing, and that the rinsing-off phase is a cleaning or a part of the cleaning. In contrast to conventional pre-washing with water, washing liquor is already used in the proposed method. This extends a duration of the action of the detergent on the soiling and, as a result, improves the efficiency of the proposed method.

In particular, it can be provided that the rinsing-off phase, preferably not a final part of the rinsing-off phase, is suitable for the continued loosening of the soiling. Since the washing liquor is reused, the adhered dirt, which still adheres to the items to be washed, can continue to swell and/or become loosened.

In order to save water consumption and to provide a highly concentrated washing liquor at the same time, it can be provided that during the loosening phase the washing liquor contains 0.5 l (liters) to 2.0 l water, preferably 1.2 l to 1.8 l water and further preferably 1.5 1 water.

In order to provide a highly concentrated washing liquor, it can be provided, in particular, that the total detergent provided and/or used for a washing program is contained and preferably is dissolved in the washing liquor from the loosening phase.

According to a further embodiment, it can be provided that the quantity of washing liquor is measured during the loosening phase such that washing liquor is dispensed from the at least one spray apparatus over a period of time during the discontinuous dispensing. The discontinuous dispensing preferably contains in each case one pause time period and an actual dispensing time period which repeatedly alternate with one another. During the one pause time period, the circulating pump is operated or not operated so that washing liquor is not dispensed from the at least one spray apparatus. During a dispensing time period, the circulating pump is operated so that the washing liquor is dispensed from the at least one spray apparatus. The dispensing over the time period permits a rapid and uniform moistening of the items to be washed, which are distributed in an irregular manner in the dishwasher cavity, and the adhered dirt.

It can thus be expedient to differentiate between dispensing in the narrower sense of an outflow and dispensing in a further sense of a method phase.

According to a further embodiment, it can be provided that the quantity of washing liquor is measured during the loosening phase such that washing liquor is dispensed in the form of a spray from the at least one spray apparatus during the discontinuous operation of the loosening phase. This has the advantage that the washing liquor is not replaced on the respectively adhered dirt, whereby the adhered dirt is loosened in an improved manner. Moreover, a detergent can be more concentrated in the washing liquor.

Preferably, the quantity of washing liquor is measured during the loosening phase such that washing liquor is dispensed only in bursts from the at least one spray apparatus during the discontinuous operation of the loosening phase. In contrast to dispensing washing liquor over a period of time, this embodiment requires a smaller quantity of washing liquor.

Starting from a uniform quantity of detergent, therefore, the concentration of detergent in the washing liquor can be further increased. Thus during the loosening phase it is possible to loosen or release adhered dirt which otherwise could be loosened or released only with a very high consumption of time, energy for generating pressure, energy for heating and/or water, i.e. with less efficiency.

It can be provided that during the discontinuous dispensing of the washing liquor dispensing is carried out at the same time only from a portion of the plurality of spray apparatuses. For example, the dishwasher has a valve facility which is designed and connected such that the control apparatus can predetermine a supply of washing liquor to one of the plurality of spray apparatuses or to a portion of the plurality of spray apparatuses. As a result, a filling level of supply lines can be reduced between the circulating pump and the plurality of spray apparatuses.

Preferably, the quantity of washing liquor is measured during the loosening phase and/or the circulating pump is operated during the discontinuous dispensing, such that a quantity of washing liquor, which is measured for wetting or only for wetting the items to be washed, is dispensed from the at least one spray apparatus. Preferably, the loosening phase is carried out for simply wetting the items to be washed. “Wetting” the items to be washed, including the adhered dirt, is understood to mean applying a very small quantity of washing liquor in terms of volume. As a result, the proportion of water in the washing liquor can be correspondingly small, so that ultimately a high concentration of detergent brings about an efficient loosening of the soiling.

The above embodiments refer to a quantity of washing liquor which permits a variable discontinuous dispensing. With a predetermined quantity of detergent, a smaller quantity of washing liquor corresponds to a water saving. “Measured” can preferably be replaced by “dosing” or “limiting”.

When measuring the quantity of washing liquor, a delayed return flow of the washing liquor dispensed from the spray apparatus/apparatuses into the pump sump is preferably taken into consideration.

According to a further embodiment, the method provides to operate the circulating pump for the discontinuous dispensing of washing liquor in an interval operation. The circulating pump is thus temporarily not driven so that electrical energy is saved.

Preferably, the circulating pump is operated in a time-controlled manner for the discontinuous dispensing of washing liquor. A switch-on time of the circulating pump lasts, in particular, 1 s (second) to 10 s. Additionally or alternatively, a switch-off time of the circulating pump lasts, in particular, 1 s to 10 s. Experiments have shown that a dishwasher can be operated particularly efficiently with these time durations.

Preferably, the control apparatus is designed and connected in order to detect a current consumption of the circulating pump. For example, a sensor can be designed and connected to this end. For example, the circulating pump itself can be designed and connected accordingly. Moreover, it can be provided that the circulating pump is operated for the discontinuous dispensing of washing liquor as a function of the detected current consumption of the circulating pump. In particular, it can be provided to switch off the circulating pump as a function of the current consumption. These options are based on the recognition that emptying the pump sump is potentially associated with a reduced current consumption of the circulating pump for each time unit. This enables the operation of the circulating pump to be controlled. For example, a return flow of the dispensed washing liquor varies depending on the type, quantity and arrangement of the items to be washed in the dishwasher cavity. It is possible for the above control to react to this variation, which is more or less unpredictable, in order to enable the proposed method to run efficiently. As a development, it can be provided that the circulating pump is switched off when the current consumption changes, which indicates a transition from high-load operation to part-load operation. This variant is able to be operated in a particularly robust manner.

According to a further embodiment, the loosening phase transitions to the rinsing-off phase by supplying water to the washing liquor. Since the quantity of washing liquor is increased, the rinsing-off is improved by means of the effects of the flow. Since the loosening phase transitions to the rinsing-off phase, the duration of the washing program is kept as short as possible.

According to a further embodiment, during the rinsing-off phase the washing liquor contains 2 l to 4 l water, preferably 2.7 l to 3.5 l water and further preferably at least 3 l water. Experiments have shown that a particularly effective rinsing-off action is achieved by means of this water quantity, or the corresponding quantity of washing liquor.

Preferably, before the loosening phase the proposed method has a preparation phase during which the washing liquor containing water and detergent is prepared. During the loosening phase, the washing liquor is distributed onto the items to be washed. Since the washing liquor is prepared before the loosening phase, this achieves a concentration of detergent in the washing liquor which is as uniform as possible and ultimately a uniform distribution of detergent on the items to be washed.

According to a further embodiment, the washing liquor has a heating facility. As an option, it is proposed that the washing liquor is heated by means of the heating facility during the loosening phase. This improves the capacity for loosening specific soiling, in particular fats. The lower the quantity of washing liquor which is not used again after the loosening phase, the more efficient it is to heat the washing liquor even during the loosening phase.

Moreover, a computer program product is proposed, said computer program comprising commands which, when the computer executes the program, cause this computer to execute the above-described method. A computer product, such as for example a computer program means, can be provided or delivered for example as a storage medium, such as for example a memory card, USB stick, CD-ROM, DVD, or even in the form of a downloadable file from a server in a network. This can take place, for example, in a wireless communication network by the transfer of a corresponding file with the computer program product or the computer program means.

According to a further aspect, a dishwasher is proposed. The dishwasher is, in particular, a household dishwasher. The dishwasher comprises a dishwasher cavity for receiving items to be washed, at least one spray apparatus, a circulating pump and a control apparatus. The spray apparatus is arranged in and/or on the dishwasher cavity in order to dispense washing liquor onto the items to be washed. The circulating pump is designed to deliver washing liquor from a pump sump of the dishwasher cavity to the at least one spray apparatus.

The embodiments and features described for the proposed method accordingly apply to the proposed dishwasher.

Further possible implementations of the invention also comprise combinations of features or embodiments described above or below relative to the exemplary embodiments which are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

Further advantageous embodiments and aspects of the invention form the subject matter of the dependent claims and the exemplary embodiments of the invention described below. The invention is explained in more detail hereinafter by way of preferred embodiments, with reference to the accompanying figures.

FIG. 1 shows a schematic perspective view of an exemplary embodiment of a household dishwasher;

FIG. 2 shows in a schematic sectional view the household dishwasher according to FIG. 1 including a circulating pump and a plurality of spray apparatuses;

FIG. 3 shows a flow diagram of an exemplary embodiment of a method for operating a dishwasher, which is executed by a control apparatus of the household dishwasher of FIG. 1;

FIG. 4 shows schematically a volume-time diagram for illustrating the quantity of washing liquor during a sequence of the method shown in FIG. 3;

FIG. 5 shows schematically a current-time diagram of a current consumption of a circulating pump during an interval operation, during a part of the sequence of the method shown in FIG. 3;

FIG. 6 shows schematically a filling level-time diagram of a filling level of a pump sump during the interval operation shown in FIG. 5;

FIG. 7 shows schematically a current-time diagram of a current consumption of a circulating pump during an interval operation, during a part of the sequence of the method shown in FIG. 3; and

FIG. 8 shows schematically a filling level-time diagram of a filling level of a pump sump during the interval operation shown in FIG. 7.

Elements which are the same or functionally the same have been provided with the same reference signs in the figures, unless specified otherwise.

FIG. 1 shows a schematic perspective view of an exemplary embodiment of a system with a household dishwasher 1. The household dishwasher 1 comprises a dishwasher cavity 2 which is able to be closed by a door 3, in particular in a water-tight manner. To this end, a sealing device (not shown) can be provided between the door 3 and the dishwasher cavity 2. The dishwasher cavity 2 is preferably cuboidal. The dishwasher cavity 2 can be arranged in a housing of the household dishwasher 1. The dishwasher cavity 2 and the door 3 can form a washing chamber 4 for washing items to be washed.

The door 3 is shown in FIG. 1 in its open position. The door 3 can be closed or opened by pivoting about a pivot axis 5 provided at a lower end of the door 3. A loading opening 6 of the dishwasher cavity 2 can be closed or opened by means of the door 3. The dishwasher cavity 2 has a bottom 7, a ceiling 8 arranged opposite the bottom 7, a rear wall 9 arranged opposite the closed door 3 and two side walls 10, 11 arranged opposite one another. The bottom 7, the ceiling 8, the rear wall 9 and the side walls 10, 11 can be produced, for example, from a stainless-steel sheet. Alternatively, for example, the bottom 7 can be produced from a plastics material.

The household dishwasher 1 also has at least one receptacle for items to be washed 12, 13, 14. Preferably, a plurality, for example three, receptacles for items to be washed 12, 13, 14 can be provided, wherein the receptacle for items to be washed 12 can be a lower receptacle for items to be washed or lower basket, the receptacle for items to be washed 13 can be an upper receptacle for items to be washed or upper basket and the receptacle for items to be washed 14 can be a cutlery drawer. As FIG. 1 further shows, the receptacles for items to be washed 12, 13, 14 are arranged one above the other in the dishwasher cavity 2. Each receptacle for items to be washed 12, 13, 14 is selectively displaceable into or out of the dishwasher cavity 2. In particular, each receptacle for items to be washed 12, 13, 14 can be inserted into the dishwasher cavity 2 in an insertion direction E and extended out of the dishwasher cavity 2 counter to the insertion direction E in an extension direction A.

FIG. 2 shows a highly schematic cross section through the household dishwasher 1. For simplification, the receptacles for items to be washed 12, 13, 14 are not shown in the cross section, for example.

The dishwasher cavity 2 has a pump sump 15 which in the installed position forms a level below the bottom 7.

For example, a line 16 leads from the pump sump 15 to a circulating pump 17. The line 16 is functionally part of the pump sump 15. The pump sump 15 is connected via the line 16 to a suction port of the circulating pump 17. Alternatively, it can be provided, for example, to arrange the circulating pump 17 at least partially directly on and/or in the pump sump 15. The pump sump 15 is connected upstream of the circulating pump 17.

A drain pump, not shown, which preferably is also connected to the pump sump 15 is provided in addition to the circulating pump 17 in the household dishwasher 1, for example. In contrast to the circulating pump 17 a drain line is connected, for example, downstream of the drain pump in order to transport water, washing liquor, food residues and/or the like out of the household dishwasher 1.

A pressure connection of the circulating pump 17, which is designed to dispense fluid, is connected to a line network 18, only indicated symbolically. The line network 18 is connected downstream of the circulating pump 17.

The line network 18 connects the circulating pump 17 fluidically to a plurality of spray apparatuses 19, 20, 21. The spray apparatus 19 is configured as a first spray arm which is arranged on the bottom 7 of the dishwasher cavity 2. The spray apparatus 20 is configured as a second spray arm which is arranged on the side wall 11 of the dishwasher cavity 2. The spray apparatus 21 is configured as a third spray arm which is arranged on the ceiling 8 of the dishwasher cavity 2. This is a preferred example; it is possible to provide more than or fewer than three spray apparatuses 19, 20, 21; it is possible for one or more or all of the spray apparatuses not to be configured as a spray arm.

The circulating pump 17 is designed to apply washing liquor F to the spray apparatuses 19, 20, 21 (see FIG. 2), wherein the washing liquor F is delivered through the line network 18.

A control apparatus 22 which is arranged, for example, on the door 3 of the household dishwasher 1 is also shown. The control apparatus 22 is designed, in particular, to operate the household dishwasher 1, for example by the control apparatus 22 executing at least one washing program.

For comparison with the proposed method described below, an exemplary conventional cleaning method is described briefly hereinafter. This starts by arranging a small quantity of detergent on an inner face of the door and the remaining detergent in a dosing compartment, not shown. For example 3 g (grams) detergent is arranged on the inner face and 19 g detergent in the dosing compartment. Then the washing program is started. Next a specific quantity of water is filled into the dishwasher cavity by being controlled, for example, by the control apparatus. This quantity of water is usually sufficient in order to permit the circulating pump to circulate continuously. Technically, the quantity which has been filled in is greater than a quantity which circulates. For example 3.1 l water is filled in. Then a pre-washing starts. The water is continuously circulated, wherein the detergent arranged on the inner face is dissolved in the water and forms the washing liquor. The circulating preferably takes place on alternating washing levels. In a next step at least one portion of the washing liquor is pumped out by means of the drain pump and removed from the household dishwasher in order to remove large particles mixed into the washing liquor. For example, at least 0.4 l washing liquor is pumped out. In a next step, a further quantity of water is added to the washing liquor. For example, at least 0.7 l water is additionally added. Preferably, more water is added than has been pumped out in the previous step. In a next step, the detergent which was previously not added is added from the dosing compartment to the washing liquor which now contains, for example, 22 g detergent and 3.4 l water. Cleaning follows. During the cleaning, the washing liquor is continuously circulated by means of the circulating pump. At the start of the cleaning, the washing liquor is generally heated up to a target temperature which is associated with heating up the items to be washed and the dishwasher cavity to the same target temperature. The target temperature is, for example, 53° C. (degrees Celsius). The cleaning preferably takes place on alternate washing levels. With the completion of the cleaning, the entire washing liquor including the food residues contained therein or soiling is pumped out by the drain pump and thus removed. The pre-washing lasts, for example, for 18 minutes and the cleaning lasts, for example, for 83 minutes. This is preferably followed by the washing program sections: rinsing with rinse aid and drying, which are not detailed further here.

This differs from an exemplary progression of a proposed method 100 executed by the control apparatus 22 of the proposed household dishwasher 1, for operating the household dishwasher 1. This progression is shown in FIG. 3.

In a first step S1 a quantity of detergent is provided. This quantity of detergent preferably contains the entire detergent, the introduction or use thereof being provided until the cleaning is completed. For example, 22 g detergent is provided.

In a next step S2, water is introduced into the dishwasher cavity 2. This quantity of water is preferably measured so that a continuous operation of the circulating pump 17 is not possible.

The quantity of water introduced is preferably measured such that the washing liquor F can be dispensed during a discontinuous dispensing, namely over a period of time, but not continuously from the at least one spray apparatus 19, 20, 21.

According to a preferred option, even less water is introduced. Thus the quantity of water introduced can be particularly preferably measured, such that it can be dispensed in bursts during a discontinuous dispensing of washing liquor F but not continuously from the at least one spray apparatus 19, 20, 21.

Preferably, when measuring the quantity of water introduced or to be introduced, the method 100 or the control apparatus 22 considers a remaining quantity of water or washing liquor which has not been pumped out or could not be pumped out by the drain pump during a previous pumping out. For example, it can be that the drain pump cannot pump out below a level of an inlet into a working space of the drain pump.

Preferably, when measuring the quantity of water introduced or to be introduced, the method 100 or the control apparatus 22 considers an expansion of the volume of washing liquor F as a result of heating the washing liquor.

According to a variant, during the step S2 1.5 l water is introduced into the dishwasher cavity 2.

According to a preferred variant, during the step S2 water is introduced into the dishwasher cavity 2 up to a filling level corresponding to a total volume of 1.5 l, for example.

According to a further preferred variant, during the step S2 at least 0.5 l to at most 2 l water is introduced into the dishwasher cavity 2.

According to a further preferred variant, during the step S2 water is introduced into the dishwasher cavity 2 up to a filling level corresponding to a total volume of at least 0.5 l to at most 2 l, for example.

In a next step S3, the washing liquor F is prepared. For example, to this end the water introduced into the dishwasher cavity 2 is mixed with the detergent provided so that the detergent is dissolved in the water.

The steps S1 to S3 can also take place in an alternative sequence S2, S1, S3, or they can be replaced by at least one step in which the washing liquor F is provided in a different manner.

In an optional next step S4, the washing liquor F and/or the dishwasher cavity 2 are heated to a target temperature. For example, the washing liquor F and the dishwasher cavity 2 are heated to a target temperature, in each case between 40° C. and 80° C., preferably in each case between 45° C. and 60° C. and for example 53° C.

In a next step S5, the control apparatus 22 controls the circulating pump such that the washing liquor F is discontinuously dispensed by the spray apparatuses 19, 20, 21.

“Discontinuous dispensing” is understood to mean, in particular, a repeated and interrupted dispensing, namely in the sequence: dispensing-not dispensing-dispensing.

Preferably, the step S5 contains a plurality of changeovers between dispensing and not dispensing.

The step S5 thus represents a loosening phase controlled by the control apparatus 22. The loosening phase is suitable for releasing or loosening soiling adhering to the items to be washed in the dishwasher cavity 2 by means of the washing liquor F.

During the loosening phase or the step S5, the circulating pump 17 is operated in a manner described below. This mode of operation is suitable for discontinuously dispensing the washing liquor F from the at least one spray apparatus 19, 20, 21.

The step S4 can be omitted, or it can be carried out before the step S5 and/or during the step S5, including at the end of the step S5.

In the next step S6, additional water is introduced into the dishwasher cavity 2. In the present example, for example, 1.6 l water is introduced into the dishwasher cavity 2.

According to a variant of the first embodiment, alternatively in step S6 firstly at most 25% of the washing liquor F corresponding for example to 375 ml, preferably at most 20% of the washing liquor F corresponding for example to 300 ml, further preferably at most 10% of the washing liquor F corresponding for example to 150 ml and further preferably at most 7% of the washing liquor F corresponding for example to 100 ml, is pumped out by means of the drain pump, for example. As a result, coarse contamination can be removed from the dishwasher cavity 2 in order to facilitate subsequent method steps. Then additional water is introduced into the dishwasher cavity 2. In the present example, the introduced quantity 1.6 l plus the pumped-out volume can correspond, so that for example 1.975 l water, preferably 1.9 l water, further preferably 1.75 l water and further preferably 1.7 l water can be introduced into the dishwasher cavity 2.

Since in step S6 no washing liquor F or at most 25% of the washing liquor F of step S5 is pumped out by means of the drain pump, the corresponding quantity or remaining quantity of detergent continues to be available for completely releasing any of the still adhering soiling from the items to be washed during the following method steps.

In a next step S7, the circulating pump 17 is operated in a controlled manner by the control apparatus 22 in order to rinse off the soiling. To this end, the circulating pump 17 is operated, for example, in continuous operation. The circulating pump is thus operated in a manner which is suitable for rinsing off the soiling. Thus step S7 corresponds to a rinsing-off phase.

The terms “discontinuous dispensing over a period of time” during the loosening phase or during the step S5 and “continuous operation” during the rinsing-off phase or during the step S7 can be differentiated in terms of time or quantity. For example, it can be provided that the “period of time” of the dispensing in the rinsing-off phase is at most 10 s (seconds), whereas a “continuous operation” is designed to be at least 20 s.

Preferably, the “discontinuous dispensing over a period of time” and the “continuous operation” differ relative to the quantity of washing liquor F in the dishwasher cavity 2, in particular in the pump sump 15 and the line 16. During the discontinuous dispensing, the total quantity of washing liquor F in the dishwasher cavity 2 and, in particular, in the pump sump 15 preferably does not permit a free choice in the duration of the time period. Rather, structural and/or operating parameters of the household dishwasher 1 preferably predetermine a maximum duration of a time period for dispensing during the discontinuous dispensing. The structural and/or operating parameters which predetermine this maximum duration contain, for example, the total quantity of washing liquor 2 and/or a flow rate of the circulating pump 17 and/or dimensions of the pump sump 15 and the line 16 and/or dimensions of the line network 18 and/or, in particular, a combination thereof. During the rinsing-off phase or during step S7, on the other hand, the continuous operation of the pump during the rinsing-off phase can be maintained for any length of time. The duration of the or each continuous operation of the circulating pump 2 is preferably predetermined by a targeted rinsing-off effect and in this regard is freely selectable.

The circulating pump 17 is operated during the rinsing-off phase in a manner which is suitable for rinsing off soiling from the items to be washed. The same relates to further controllable facilities of the household dishwasher 1, for example facilities for the targeted control and/or selective interruption of a fluid flow through the line network 18 and/or for example an additional spray apparatus, such as in particular a controllable intensive spray apparatus.

If the circulating pump 17 is operated during the rinsing-off phase for rinsing off soiling from the items to be washed, for example, this does not exclude that the washing liquor F continues to loosen adhered dirt in the meantime. The reuse of the washing liquor F from the loosening phase by at least 75% during the rinsing-off phase has the advantages, amongst other things, that the detergent contained therein already acts in a loosening manner during the loosening phase and continues to act in a loosening manner during the rinsing-off phase.

The step S5 or the loosening phase preferably forms a pre-washing or preferably replaces the above-described previous form of pre-washing. Accordingly, the step S7 or the rinsing-off phase preferably forms a cleaning or preferably replaces the above-described previous form of cleaning.

Hereinafter the loosening phase is compared with the pre-washing and the rinsing-off phase is compared with the cleaning.

During the loosening phase, significantly less water or a smaller quantity of washing liquor F is used than during the rinsing-off phase. In this regard, the loosening phase and the rinsing-off phase correspond to the pre-washing and cleaning.

During the loosening phase, highly concentrated washing liquor F is used, whereas during the rinsing-off phase medium-concentrated washing liquor F is used. For example, the washing liquor F from the loosening phase contains 22 g detergent dissolved in 1.5 l water, whereas the washing liquor F from the rinsing-off phase contains 16.5 g to 22 g detergent dissolved in 3.1 l water. In this regard, the loosening phase and the rinsing-off phase represent an improvement relative to the known pre-washing with, for example, 3 g detergent dissolved in 3.1 l water and the known cleaning or cleaning with, for example, 21.6 g detergent dissolved in 3.4 l water. In the case of doubt, these numbers refer to specific test conditions but they illustrate that the proposed method leads to a higher concentration of detergent, whereby soiling is more effectively loosened.

During the loosening phase, it is possible to provide a heating of the washing liquor F and thus associated therewith an early loosening of greasy soiling, whereas for efficiency reasons a heating was previously provided only after the washing liquor was replaced for the main cleaning.

The loosening phase according to the proposed method is designed to enable the highly concentrated washing liquor F to act as early as possible on the soiling. The loosening phase is thus designed primarily for a chemical loosening of the soiling. The known pre-washing is designed to release coarse soiling by means of a water jet or washing liquor jet, and then to remove it as quickly as possible from the dishwasher cavity 2. The previously known pre-washing is thus primarily designed to release the soiling mechanically. The small quantity of detergent in the washing liquor F in the known methods, for example, is measured to prevent a re-adhering of rinsed-off coarse soiling and in this case primarily serves for a smooth operation of the machine with a long service life, instead of an early and rapid cleaning of the items to be washed.

It should not go unmentioned that the proposed method leads to a time saving. Since the detergent is already contained in the washing liquor F during the loosening phase, the duration of the rinsing-off phase can be shortened relative to the duration of the cleaning, in order to implement the same action time of the detergent on the soiling.

Finally a step S8 follows. In the step S8, the washing liquor F, including the released or floating soiling, is pumped out by means of the drain pump from the household dishwasher 1.

In a following step S9 a rinsing with rinse aid, a drying and/or the like can take place.

FIG. 3 shows the proposed method 100 in a quantity-time diagram. A progressive time is plotted along the x-axis denoted by “t” and a quantity of washing liquor F in the dishwasher cavity 2 is plotted along the y-axis denoted by “V”. The quantity is preferably a volume. The quantity is preferably a unit which can be detected via a sensor.

During the steps S1, S2, S3 the control apparatus 22 increases the quantity of washing liquor F from 0 or close to 0 or a structurally predetermined remaining quantity to a quantity V1. The quantity V1 corresponds, for example, to 1.5 1. The quantity V1 permits only a discontinuous dispensing of the washing liquor F.

During the steps S4, S5, the control apparatus 22 carries out the heating and the loosening phase. For illustrating the discontinuous dispensing of the washing liquor F during the loosening phase, the progression of the quantity in this region is shown as a zig-zag line. The quantity of washing liquor F in the dishwasher cavity 2, however, does not change due to the discontinuous dispensing.

The steps S1, S2, S3, S4 and S5 together last for the time duration T1, for example 18 min (minutes).

Subsequently during the step S6 the control apparatus 22 increases the volume of the washing liquor F again from the quantity V1 to the quantity V2. The quantity V2 permits a continuous dispensing of the washing liquor F. The quantity V2 corresponds, for example, to 3.11.

During the step S7, the control apparatus 22 carries out the main cleaning or the rinsing-off phase.

The steps S6 and S7 together last for the time duration T2, for example less than 83 min, such as for example between 65 min and 83 min.

During the step S8 the control apparatus 22 pumps out the washing liquor by means of the drain pump so that the quantity of washing liquor reduces from V2 back to 0 or close to 0 or a structurally predetermined minimum quantity.

A control strategy is described hereinafter.

FIG. 5 shows a current consumption-time diagram for illustrating an interval operation of the circulating pump 17. FIG. 6 shows a time progression of a filling level H of the washing liquor F in the pump sump 15 in a filling level-time diagram.

The interval operation takes place repeatedly during the loosening phase. FIGS. 5, 6 do not necessarily show a start or an end of the loosening phase.

The pump sump 15 is filled with washing liquor F up to an upper filling level HO to a time to. Before the time to, the circulating pump 17 is controlled by the control apparatus 22 in order not to be switched on. Thus a current consumption 1 of the circulating pump 17 is at the low level 10.

At the time to the circulating pump 17 is switched on by the control apparatus 22. The current consumption 1 by the circulating pump 17 rises to the level 11.

The circulating pump 17 delivers the washing liquor F from the pump sump 15 into the line network 18. A rising level of washing liquor F in the line network 18 causes a rising counter-pressure which the circulating pump 17 has to overcome. Thus the circulating pump 17 transitions to full-load operation and the current consumption rises to the highest value 14. In the meantime, the filling level H drops to the lower filling level HU.

In this embodiment, the quantity V of washing liquor F in the dishwasher cavity 2 is measured precisely such that a dispensing of washing liquor F is only possible in bursts from the spray nozzles 19, 20, 21. This moment t1 is denoted technically as a spray burst 23.

The filling level H has dropped to the lower filling level HU, and thus the circulating pump 17 no longer receives from the pump sump 15 a volumetric flow of washing liquor F corresponding to a flow rate. The circulating pump 17 thus transitions at this moment t1 into part-load operation and the current consumption drops from the high level 14 to the lower level 13.

This drop in current consumption 1 is detected by the circulating pump 17 or a sensor and communicated to the control apparatus 22.

While the filling level H continues to remain at the value of the lower filling level HU and the current consumption 1 drops from the level 13 back to the level N2, the control apparatus 22 stops an operation of the circulating pump 17.

As a result, at a moment t2, the circulating pump 17 is switched off and the current consumption 1 drops from the level 12 to the start level 10.

Since the circulating pump 22 is switched off, it does not deliver any washing liquor F into the line network 18. As a result, the filling level H rises in the pump sump 15 back to the upper filling level HO.

Since the control apparatus 22 detects by a filling level sensor or, as a result of waiting for a predetermined period of time, it is assumed by the program that the filling level has risen again, the control apparatus 22 switches on the circulating pump 17 again at a time t3. The described cycle starts again. The time t3 of a previous cycle is preferably a time t0 of a following cycle.

A period of time Z1 from t 0 to t2 lasts, for example, 5 s (seconds) and a period of time Z2 from t 2 to t3 lasts, for example, 2 s. A cycle time therefore lasts, for example, 7 s.

The repeating cycles from t0 to t3 are denoted as an interval operation of the circulating pump 17.

The interval operation described in the context of this embodiment is a preferred example of interval operation.

In a variant of the second embodiment, the periods of time Z1 and/or Z2 can be predetermined, even individually. In this regard, a corresponding sensor can be dispensed with and the control apparatus 22 can implement a time control of the interval operation.

The control of FIGS. 5 and 6 is shown again in FIGS. 7, 8. However, a larger quantity V1 of washing liquor F is provided in the dishwasher cavity 2. This has the result that, instead of the spray burst 23, the washing liquor F can be dispensed from the spray apparatuses 19, 20, 21 over a period of time Z3 before the filling level H has dropped to the lower filling level HU. As a result, even in the situation shown in FIGS. 7, 8, it leads to the circulating pump 17 changing to part-load operation and thus displaying less current consumption and being switched off by the control apparatus 22. In other words, even in the situation in FIGS. 7, 8, the spray liquor F is discontinuously dispensed and the circulating pump 17 is operated in an interval operation.

According to a further embodiment, not shown in the figures, the circulating pump 17 is not switched off by the control apparatus 22 in part-load operation, but the circulating pump 17 continues to be operated by the control apparatus 22 in part-load operation. As a result, the line network 18 remains partially filled. If the circulating pump 17 then continues to be operated by the control apparatus 22 in full-load operation, washing liquor F can be dispensed more rapidly from the spray apparatuses 19, 20, 21. The period of time Z1 can thus be reduced.

While the present invention has been described with reference to exemplary embodiments, it can be modified in many different ways.

REFERENCE SIGNS USED

• • 1 Household dishwasher
  • 2 Dishwasher cavity
  • 3 Door
  • 4 Washing chamber
  • 5 Pivot axis
  • 6 Loading opening
  • 7 Bottom
  • 8 Ceiling
  • 9 Rear wall
  • 10 Side wall
  • 11 Side wall
  • 12 Receptacle for items to be washed
  • 13 Receptacle for items to be washed
  • 14 Receptacle for items to be washed
  • 15 Pump sump
  • 16 Line
  • 17 Circulating pump
  • 18 Line network
  • 19 Spray apparatus
  • 20 Spray apparatus
  • 21 Spray apparatus
  • 22 Control apparatus
  • 23 Spray burst
  • 100 Method
  • A Extension direction
  • E Insertion direction
  • F Washing liquor
  • H Filling level
  • HO Upper filling level
  • HU Lower filling level
  • 1 Current consumption
  • 11 Level
  • 12 Level
  • 13 Level
  • 14 Level
  • t Time
  • T1 Duration
  • T2 Duration
  • t0 Time
  • t1 Time
  • t2 Time t3 Time
  • V Quantity
  • V1 Quantity
  • V2 Quantity
  • Z1 Period of time
  • Z2 Period of time
  • Z3 Period of time

Claims

1-15. (canceled)

16. A method for operating a dishwasher, the method comprising:

controlling a loosening phase by a control apparatus of the dishwasher for loosening soiling adhering to items to be washed in a dishwasher cavity by means of a washing liquor which is dispensed by a spray apparatus arranged in or on the dishwasher cavity;

during the loosening phase, operating a circulating pump, which is designed to deliver the washing liquor from a pump sump of the dishwasher cavity to the spray apparatus, for discontinuous dispensing of the washing liquor from the spray apparatus; and

rinsing off the soiling in a rinsing-off phase, with at least 75% of the washing liquor from the loosening phase being reused during the rinsing-off phase.

17. The method of claim 16 for operating a household dishwasher.

18. The method of claim 16, wherein an entire quantity of the washing liquor from the loosening phase is reused during the rinsing-off phase.

19. The method of claim 16, wherein the loosening phase is a pre-washing or a part of the pre-washing, and wherein the rinsing-off phase is a cleaning or a part of the cleaning.

20. The method of claim 16, further comprising measuring a quantity of the washing liquor during the loosening phase such that the washing liquor is dispensed from the spray apparatus over a period of time during the discontinuous dispensing.

21. The method of claim 16, further comprising measuring a quantity of the washing liquor during the loosening phase such that the washing liquor is dispensed in a form of a spray burst from the spray apparatus during the discontinuous dispensing.

22. The method of claim 16, further comprising measuring a quantity of the washing liquor during the loosening phase and/or operating the circulating pump during the discontinuous dispensing, such that a quantity of the washing liquor, which is measured for wetting the items to be washed, is dispensed from the spray apparatus.

23. The method of claim 16, further comprising operating the circulating pump for discontinuous dispensing of the washing liquor in an interval operation.

24. The method of claim 16, wherein the circulating pump is operated in a time-controlled manner for the discontinuous dispensing of the washing liquor, with a switch-on time of the circulating pump lasting 1 s to 10 s, and/or with a switch-off time of the circulating pump lasting 1 s to 10 s.

25. The method of claim 16, further comprising the control apparatus detecting a current consumption of the circulating pump, wherein the circulating pump is operated for discontinuous dispensing of washing liquor as a function of the detected current consumption of the circulating pump.

26. The method of claim 25, further comprising switching off the circulating pump when the current consumption changes, which indicates a transition from high-load operation to part-load operation.

27. The method of claim 16, further comprising supplying water to the washing liquor when the loosening phase transitions to the rinsing-off phase.

28. The method of claim 16, further comprising preparing the washing liquor containing water and detergent during a preparation phase before the loosening phase.

29. The method of claim 16, further comprising heating the washing liquor by a heating facility during the loosening phase.

30. A computer program product comprising a computer program embodied in a non-transitory computer readable medium and comprising commands which, when the computer program is loaded into a computer and executed by the computer, cause the computer to carry out the method set forth in claim 16.

31. A dishwasher, comprising:

a dishwasher cavity for receiving items to be washed;

a spray apparatus arranged in and/or on the dishwasher cavity in order to dispense washing liquor onto the items to be washed;

a circulating pump designed to deliver the washing liquor from a pump sump of the dishwasher cavity to the spray apparatus; and

a control apparatus designed to control a loosening phase for loosening soiling adhering to items to be washed in a dishwasher cavity by means of the washing liquor, to operate the circulating pump during the loosening phase for discontinuous dispensing of the washing liquor from the spray apparatus, and to rinse off the soiling in a rinsing-off phase, with at least 75% of the washing liquor from the loosening phase being reused during the rinsing-off phase.

32. The dishwasher of claim 31, constructed in a form of a household dishwasher.

33. The dishwasher of claim 31, wherein the control apparatus is designed to detect a current consumption of the circulating pump and to operate the circulating pump for discontinuous dispensing of washing liquor as a function of the detected current consumption of the circulating pump.

34. The dishwasher of claim 31, wherein the control apparatus is designed to enable preparation of the washing liquor containing water and detergent during a preparation phase before the loosening phase.

35. The dishwasher of claim 31, further comprising a heating facility designed to heat the washing liquor during the loosening phase.