CN101961237A - Dish-washing machine with filter system of optimization - Google Patents

Abstract

The invention discloses a dishwasher, in particular a domestic dishwasher (1), having: a washing compartment (4) in which a certain number of standard compartments can be loaded; and a filter system ( 20) The filter system has a microfilter (28) for filtering microscopic dirt from the washing liquid circulated during operation of the circulation pump (11) as circulation flow (US) , wherein, during operation of the circulation pump (11), the first partial flow (US1) of the circulating flow (US) flows through the microfilter (28), the second partial flow (US2) of the circulating flow (US) is led Passing by a microfilter (28), characterized in that the microfilter (28) has a filter surface of at least 14 cm ² , at most 28 cm ² , in particular at least 16 cm ² , at most A filter surface of 26 cm ² and particularly preferably a filter surface of at least 18 cm ² and at most 24 cm ² .

Description

Dishwashers with an optimized filter system

technical field

The invention relates to a dishwasher, in particular a domestic dishwasher, having: a washing compartment in which a certain number of standard compartments can be loaded; and a filter system with micro filter, said microfilter for filtering out microscopic dirt from the washing liquid circulated as a circulation flow during operation of the circulation pump, wherein during operation of the circulation pump a first partial flow of the circulation flow flows through A microfilter, the second partial flow of the recirculation flow is directed past the microfilter.

Background technique

Commercially available domestic dishwashers have a washing compartment equipped with holding means for receiving items to be washed. The holding means may typically comprise a cutlery basket or the like. The capacity of the washing compartment of the dishwasher is in this case structurally predetermined in particular by the inner volume of the washing container and the shape of the holding device.

In domestic dishwashers, the capacity is specified by the number of standard compartments that can be loaded simultaneously with associated meal items into the washing compartment of the domestic dishwasher. A standard compartment according to European standard EN50242 typically includes: a large plate with a diameter of 26 cm, a soup plate with a diameter of 23 cm, a snack plate with a diameter of 19 cm, a saucer with a diameter of 14 cm, a cup with a capacity of 0.2 liters, a drink with a capacity of 0.25 liters A cup, a fork with a length of 184mm, a spoon with a length of 195mm, a knife with a length of 203mm, a teaspoon with a length of 126mm and a dessert spoon with a length of 156mm.

To test the capacity of a domestic dishwasher, a specific number of standard compartments and a set of meal items are used. For the desired capacity of six or fewer standard compartments, use a 32cm diameter stove platter, a 16cm diameter serving dish, a 13cm diameter serving dish, two serving spoons each 260mm in length , a dinner fork with a length of 192mm, and a soup spoon with a length of 175mm. At a desired capacity of seven or more standard compartments, a 19 cm diameter dinner plate was used, and a 35 cm diameter oven platter was used instead of a 32 cm diameter oven platter.

Commercially available dishwashers have a control device for automatically controlling the time sequence of the washing process according to the washing program. In this case, usually there are multiple washing programs stored in the control device, and the operator can respectively select a washing program from the multiple washing programs to perform a washing process. In this case, different washing programs are adapted to different corresponding requirements, which result in particular from the quantity of crockery actually introduced, the type of crockery and the degree of soiling of the crockery.

Washing programs usually include, inter alia, a cleaning phase in which the circulation pump is at least sometimes switched on, which generates a circulation flow of washing liquid which is applied to the items to be washed in order to remove the Loosen dirt and wash it away. Washing fluids involve dispensing systems in which the main component is water. Depending on the time sequence of the cleaning phases, the wash liquor may include cleaning agents, such as surfactants, and soils from the items to be washed. In order to prevent the dirt contained in the washing liquid in the circulating flow from returning to the items to be washed, a filter system is provided through which the circulating flow of washing liquid is led such that the dirt contained in the washing liquid is at least partly Remains in the filter system. The filter system is in this case implemented in such a way that the retained dirt can be pumped out of the filter system at specific points in time by means of a discharge stream comprising washing liquid, in order to avoid the filter system due to too large becomes clogged with dirt, wherein the discharge flow can be generated by operating a discharge pump.

The filter system of a dishwasher has at least one microfilter for removing fine dirt particles from the circulating flow of washing liquid. In this case, a first portion of the circulation flow delivered by the circulation pump is guided through the microfilter in a first direction. A second portion of the circulating flow is directed past the microfilter via a bypass or branch. In this way, high circulation flows can be generated.

In recent years, greater demands have been placed on greater energy efficiency of domestic dishwashers. The underlying reason is that electricity and water prices have continued to rise. In addition, other aspects of environmental awareness among residents have increased.

A disadvantage of existing dishwashers is that these no longer meet current requirements with regard to energy efficiency and environmental compatibility.

Contents of the invention

The object of the present invention is to increase the efficiency of existing dishwashers.

The above object is achieved by the microfilter having a filter surface of at least 14 cm ² , at most 28 cm ^{2 , in particular at least 16 cm 2 ,} at most 26 cm ² , and particularly preferably Has a filter surface of at least 18 cm ² , at most 24 cm ² .

In the dishwasher according to the invention, the microfilters are designed to be oversized for a certain number of standard compartments compared to corresponding microfilters of known dishwashers. Thus, the microfilter has a filter surface of at least 14 cm ² , in particular a filter surface of at least 16 cm ² , particularly preferably a filter surface of at least 18 cm ² , per standard compartment provided. In this way, the microfilter can accept larger volumes of dirt without it becoming clogged in the process. This means that, while the cleaning phase is being carried out, it is not necessary to frequently pump out retained microscopic dirt from the filter system by means of the pumped flow of washing liquid. Consequently, the drain pump does not have to be switched on as often during the cleaning phase, so that overall less washing liquid is pumped. This also results in less fresh water having to be supplied to the dishwasher during the cleaning phase. In this way, the water consumption of the dishwasher can be significantly reduced.

With a suitable layout of the microfilter, the same cleaning effect can generally be achieved with a washing program whose cleaning phase only provides exactly one cleaning process, for which, in a standard dishwasher, such The washing program in which the cleaning phase has a pre-washing process and a cleaning process. In this case, the water consumption of the dishwasher during the cleaning phase can typically be halved from 8 liters to 4 liters.

However, at this time in many cases it is also possible to achieve a cleaning effect which, in the case of existing dishwashers, requires a prewash process and two cleaning A single cleaning process is achieved. In this case, the water consumption during the cleaning phase actually drops by a third, for example from 12 to 8 liters. In general, it has been determined that in the dishwasher according to the invention, while maintaining the cleaning effect, washing programs are possible in which the cleaning phase requires fewer partial washing processes than is the case with existing dishwashers of.

In addition to achieving the required water savings, the possible omission of the pre-wash process at this point also saves electrical energy. That is to say, if the washing process starts directly with the cleaning process, the heating of the dishwasher is also switched on directly. This increases the average temperature of the wash liquor during the cleaning process compared to a cleaning phase in which the pre-wash process is performed with rather cold water. A higher average temperature produces a higher thermal cleaning effect, so that the overall duration of the cleaning phase can generally be reduced. In many cases it is also possible to reduce the maximum temperature in the cleaning phase. This all leads to energy savings.

For each standard compartment provided, by making the lower or minimum limit of the filter surface of the microfilter to be at least 14 cm ² , especially at least 16 cm ² , especially preferably at least 18 cm ² and by making the filter surface of the microfilter An upper limit of at most 28 cm ² , in particular at most 26 cm ² , especially preferably at most 24 cm ² , enables a small design of the microfilter, which still enables the inventive increase in efficiency.

According to an advantageous embodiment of the invention, the microfilter has through-holes for the washing liquid, the through-holes having a cross-section of at least 0.025 mm ² , at most 0.06 mm ² , in particular at least 0.03 mm ² , at most 0.05 mm 2 . A cross section of mm ² , particularly preferably a cross section of at least 0.035 mm ² and at most 0.045 mm ² . The stated lower limit for the cross-section of the through-holes ensures that the microfilter has a sufficiently low flow resistance. At the same time, the specified upper limit for the cross-section of the through-holes ensures that the microfilter has a sufficient filtering effect.

According to an advantageous development of the invention, the ratio of the total surface area of the through-holes of the microfilter to the total filter surface area of the microfilter is at least 25%, at most 50%, in particular at least 30%, at most 45%, particularly preferably At least 35%, at most 40%. The values given result in a favorable ratio between flow resistance and stability of the microfilter.

According to an advantageous development of the invention, during operation of the discharge pump, at least a first part of the pumped flow passes through the microfilter, wherein the direction of flow of the first part of the pumped flow is in the same direction as that of the first part of the circulation flow. The direction of flow is reversed. In this way, automatic cleaning of the microfilter can be achieved.

According to an advantageous development of the invention, the microfilter is arranged between the circulation chamber and the collection chamber. In this case, a circulation chamber is to be understood as a chamber from which washing liquid can be conducted to the circulation pump. Thus, for example, a connecting line can be provided through which the washing liquid reaches the circulation pump by gravity. Thus, the washing liquid cleaned by the microfilter is immediately available for further circulation. On the other hand, a collection chamber is to be understood as a chamber from which washing liquid and/or dirt can be pumped away by means of a discharge pump. This arrangement of the given microfilter enables the dirt filtered out of the washing liquid by the microfilter to be collected in the collection chamber and then be removed in a simple manner by switching on the drain pump.

According to an advantageous development of the invention, the filter system has a fine filter which is arranged upstream of the microfilter with respect to the first partial flow of the circulation flow, wherein the fine filter has at least as much as the microfilter The filter surface is as large as the filter surface.

The use of another fine filter provides an initial cleaning of the recirculation flow. The finer microscopic dirt that has passed through the fine filter can at least partially be caught by the micro filter. Thus, the filter arrangement, now a two-stage arrangement, further reduces the tendency to clog the microfilter. The above-mentioned size selection of the provided microfilter has the effect in this case that clogging of the microfilter is largely prevented even with a large amount of microscopic dirt.

According to an advantageous development of the invention, the microfilter is a microfilter cartridge arranged in an upright position. The microfilter is implemented as a vertical microfilter cartridge so that the microfilter has a good flow capacity and allows fine dirt to be deposited in the lower area of the collection chamber, so that the deposited fine dirt can in any case only A small portion of the filter surface of a microfilter is clogged. Furthermore, a compact design of the filter system is possible.

According to an advantageous development of the invention, the fine filter is a fine filter cartridge arranged in an upright position, said fine filter cartridge being arranged concentrically to the microfilter cartridge. This also yields further advantages with regard to the flow capacity of the two-stage filter arrangement and with regard to the space-saving arrangement.

According to an advantageous development of the invention, the filter system comprises a further, namely a second fine filter, for discharging the first partial flow of the pumped flow during operation of the discharge pump and/or of the circulating flow during operation of the circulation pump. A second partial flow is led from the washing compartment into the circulation chamber through said second fine filter. Said further fine filter is available in pumping mode for the first partial flow of the pumped flow from the washing compartment to the interior of the circulation chamber to enter from there through the microfilter and through the possibly present first fine filter Or clean it before flowing into the collection chamber. This causes the pre-cleaned washing liquid to flow through the microfilter and possibly the first fine filter in pump mode. In this way, it is prevented that minute dirt, which cannot be loosened and removed, collects at the microfilter on one side of the circulation chamber. In addition, a further fine filter is used to guide the first partial flow of the circulation flow through the microfilter in circulation mode and, if necessary, also through the first fine filter and to clean it in this way. This enables a greater circulation flow to be generated and also prevents uncleaned washing liquid from reaching the circulation chamber.

According to an advantageous development of the invention, the further second fine filter is embodied as a flat filter which is arranged in the bottom of the washing compartment. In this way, a large filter surface can be achieved, which reduces the tendency for another fine filter to clog.

According to an advantageous development of the invention, the filter system can comprise a coarse filter through which the second partial flow of the pumped flow during operation of the discharge pump and/or the first partial flow of the circulation flow during operation of the circulation pump passes Said coarse filter is guided from the washing compartment into the collection chamber, wherein the coarse filter is embodied to hold back objects which, due to their size, cannot be pumped away by the pumped flow. The coarse filter may be implemented so that larger objects such as tableware items, toothpicks, etc. cannot reach the interior of the filter system. This prevents the filter system from becoming clogged with such items. It also prevents damage to the microfilter and, if necessary, the fine filter. Furthermore, damage to the discharge pump and/or circulation pump is prevented.

According to an advantageous development of the invention, the coarse filter is a coarse filter cartridge arranged in an upright position. This has further advantages with regard to the compact design of the filter system.

According to an advantageous development of the invention, a washer fluid reservoir is provided which is designed for temporarily holding washer fluid.

Such a washing liquid reservoir makes it possible to store at a certain time a certain amount of washing liquid which is not required during the washing process. This amount of wash solution can then be used at a later point in time. This prevents washing liquid which is in principle still usable from being pumped out of the dishwasher if this would cause problems at a certain point in time or would not be used. The reuse of the stored washing liquid in this case leads to a further reduction in the water consumption of the dishwasher.

According to a particularly preferred exemplary embodiment of the invention, the washing liquid reservoir is provided for receiving washing liquid at the end of an intermediate washing process and/or a rinsing process of a washing process and at the beginning of a cleaning phase of a subsequent washing process Dispense wash solution. With conventional dishwashers, the washing liquid is pumped away at the end of the intermediate washing process in order to be able to carry out subsequent rinsing processes with fresh water. Likewise, at the end of the rinsing process, the washing liquid is completely or partially pumped away, as this is not required in the subsequent drying process. The washing liquid of the intermediate washing process or of the rinsing process is usually only slightly soiled. Therefore, this washing solution can generally be used in any cleaning phase of the subsequent washing process. The indicated use of the washing liquid reservoir has the effect that less or even no fresh water needs to be sucked in at the start of the cleaning phase of the subsequent washing process. This leads to a further significant reduction in the water consumption of the dishwasher.

Description of drawings

Further developments of the invention are described in the dependent claims. In the following, the present invention and its improvements are explained in more detail with reference to the accompanying drawings. The figures show the following schematic diagrams:

Figure 1 shows an exemplary embodiment of a domestic dishwasher according to the invention in a schematic side view;

Figure 2 shows a detailed view of the dishwasher of the present invention;

Figure 3 shows a timing diagram of a normal washing process of a dishwasher of the prior art; and

Fig. 4 shows a typical sequence of a normal washing process of the dishwasher of the present invention.

Detailed ways

In FIGS. 1-4 , elements having the same function and mode of operation are denoted by the same reference numerals, respectively.

FIG. 1 shows an exemplary embodiment of a domestic dishwasher 1 according to the invention in a schematic side view, wherein only those components which are relevant for understanding the invention are shown and identified with reference numerals. The dishwasher 1 has a washing container 2 which can be closed by a door 3 so that a closed washing compartment 4 is created for washing items, in particular for washing tableware. In FIG. 1 the door 3 is shown in its closed position. The door 3 can be moved by pivoting it about an axis at right angles to the plane of the drawing into an open position in which the door is oriented substantially horizontally and which allows the loading or removal of cutlery.

The dishwasher 1 has an upper cutlery basket 5 and a lower cutlery basket 6 for positioning dishes. The upper cutlery basket 5 is arranged in this case on telescopic rails or slide-out rails 7 , which are each correspondingly attached to the side walls of the washing container 2 . When the door 3 is opened, the cutlery basket 5 can be removed from the washing container 2 by means of the pull-out or slide-out rail 7 , which facilitates loading or unloading of the upper cutlery basket 5 . The lower cutlery basket 6 is arranged in a similar manner on the telescopic or slide-out rail 8 .

The capacity of the dishwasher 1 is predetermined in particular by the design of the washing container 2 and the cutlery baskets 5 , 6 . In the case of a width of 60 cm, the dishwasher of the present invention can typically accommodate 12-14 standard compartments, and in the case of a width of 45 cm, typically 6-7 standard compartments.

The dishwasher 1 also comprises a supply device 9 for fresh water FW, which is embodied in such a way that fresh water supplied from the outside can reach the interior of the washing compartment 4 in a controlled manner. The fresh water FW supplied in a controlled manner collects due to its gravity as washing liquid 5 in a collection tank 10 forming the lower half of the washing container 2 . The collection tank 10 is in this case connected to a circulation pump 11 , by means of which the washing liquid 5 can be pumped out of the collection tank 10 and via the heater 12 to the water switch 13 during the circulation phase of the washing process. The heater is a component of the circulation pump 11, in particular it can be integrated into the circulation pump, if required.

The water switch 13 has three output terminals, wherein the first output terminal is connected to the upper spray arm 14 and the second output terminal is connected to the lower spray arm 15 . The water switch 13 can in this case be controlled so that the wash water S conveyed by the circulation pump 11 during washing of the items to be washed is optionally passed through one of the spray arms 14, 15 or through both spray arms 14, 15. The shower arms 14 , 15 are conveyed into the washing container 2 in order to wash the dishes located there.

The water switch 13 can also be controlled such that the washing liquid S conveyed by the circulation pump 11 can be pumped via the third output into the washing liquid reservoir 16 . The liquid reservoir 16 is used to hold a certain amount of washing liquid S that is not needed at a certain time, and to dispense it when it is needed again. For the latter purpose, the liquid reservoir 16 has a controllable outlet, not shown in the figures, via which outlet the stored wash liquid S can be dispensed into the wash container 2 .

In order to be able to remove wash water S which is no longer needed from the wash container 2 , a drain pump 17 is provided which is connected to the collection tank 10 and to the waste water connection 18 . Thus, the wash water S can be pumped away as waste water AW by means of the discharge pump 17 during the pumping phase of the washing process. A dispensing device 19 is also provided in order to provide the wash water S with cleaning agents and/or cleaning aids, for example cleaning agents.

The collection tank 10 is equipped with a filter system 20, which is implemented to remove larger objects such as bones, toothpicks, which could damage or block the circulation pump 11, the discharge pump 17 and/or their supply and discharge lines. And/or items of cutlery can remain in the washing compartment 4 even if they fall out of the cutlery baskets 5 , 6 and rest on the bottom 21 of the washing container 2 . Furthermore, the filter system 20 is implemented in such a way that when the circulation pump 11 is switched on, the circulation flow of washing liquid S guided through the filter system 20 is cleaned by blocking the dirt contained in the circulation flow of washing liquid S, In order to prevent dirt from returning to the items to be washed and to prevent contamination of the washing liquid reservoir 16 . The filter system 20 is also embodied in such a way that the trapped dirt can be pumped out via the waste water connection 18 by switching on the discharge pump 17 .

The dishwasher 1 also has a control device 22 which is arranged in the region of the control panel of the door 3 and which is connected for control purposes to the supply device 9 , the circulation pump 11 , the heater 12 , the water distributor 13 , a washing liquid reservoir 16 , a discharge pump 17 and a distribution device 19 . The control device 22 is embodied in this case in particular to automatically control the sequence of the washing process according to the washing program. If desired, the control device 22 can also be arranged at another location in the dishwasher, for example in its bottom module below the dishwasher 2 .

FIG. 2 shows a detailed view of the inventive dishwasher of FIG. 1 . In this case, the collecting tank 10 and the filter system 20 arranged in the bottom 21 of the washing container are shown in a cutaway view.

The filter system has a first fine filter 23 which is embodied in the shape of a cylinder, the axis of which is arranged in an upright position. The underside of the cylindrical fine filter 23 is located on the upper side of the bottom 24 of the collection basin 10 . The cylindrical fine filter in this case extends upwards to the upper side of the filter system 20 .

A collecting mouth 25 is provided in the bottom 24 of the collecting tank 10, said collecting mouth being connected to the discharge pump shown in FIG. 1 via a hose or the like. In this case, the connection nozzle 25 is arranged in the region of the bottom 24 which is surrounded by the fine filter cartridge 23 in a ring, in particular is protected by a ring. A further connection nozzle 26 is embodied in the bottom outside this region, said connection nozzle being connected to the circulation pump shown in FIG. 1 via a hose not shown in the figure or by a similar structure.

The fine filter 23 has through holes 27 through which the washing liquid S can pass. The dimensions of the through openings are selected in this case such that coarse dirt of the washing liquid S is blocked. In circulation mode, in which the circulation pump of the dishwasher is switched on, a circulation flow US of washing liquid is produced, wherein the first partial flow US1 is pumped by the circulation pump into the washing liquid S radially from the inner side of the cylindrical fine filter 23. Exhaust outward. In this way, at least a part of the fine dirt contained in the washing liquid is held in the cylindrical fine filter 23 . A part of this dirt falls to the bottom 24 of the collection tank, and another part of the dirt adheres to the inside of the cylindrical fine filter 23 . In order to be able to clean the washing liquid S more fully, a microfilter 28 is provided, which is also embodied in the shape of a cylinder and is arranged concentrically around the fine filter 23 . The dirt contained in the first partial flow that can pass through the fine filter 23 is separated in this case on the inside of the microfilter cartridge 28 because the through-holes 29 of the microfilter cartridge 28 are designed to be finer than The filter 23 has small through holes.

The filter surface of the cylindrical microfilter 28 is designed in this case in such a way that only a significantly greater amount of dirt would cause the microfilter to become clogged than is the case with conventional dishwashers. In this way, retained dirt needs to be removed from filter system 20 significantly less.

A similar possible removal of dirt from the filter system 20 takes place in the pumping phase, in which a pumping flow AS is generated by switching on the discharge pump to pump out the washing liquid S. The first partial flow AS1 of the pumped flow AS is in this case guided through a cylindrical microfilter 28 and a cylindrical fine filter 23, wherein the direction of the first partial flow AS1 of the pumped flow AS is in the same direction as that of the circulating flow. The flow direction of the first partial flow US1 is reversed because the first partial flow AS1 is sucked in from the outside, in particular radially inwards by means of the discharge pump 17 in its suction mode. The dirt adhering to the inner side of the cylindrical microfilter 28 and the inner side of the fine filter cartridge 23 is loosened and the dirt particles like those on the bottom of the collecting tank 10 are carried away by means of the pumping flow AS .

The area surrounded by the microfilter cartridge is also referred to as collection chamber 30 . Similar to the filter surface of the microfilter cartridge 23, the volume of the collection chamber 30 is significantly larger compared to a conventional dishwasher of similar capacity. This enables the operating performance of the filter system to be maintained even when a large amount of dirt has been deposited due to the washing liquid S.

The space in collection tank 10 outside the microfilter cartridge is also referred to as circulation chamber 31 . The circulation chamber 31 is directly connected to the washing compartment arranged above the filter system 20 via a further fine filter 32 which is substantially flat. The flat fine filter 32 makes it possible for the first partial flow AS1 of the pumped flow AS to enter or flow from the circulation chamber 31 from the outside, in particular radially inwards, into the collection pan 10 in the pumping mode of the discharge pump. In this case, the flat fine filter 32 has through-openings 33 so that dirt can possibly be prevented from entering the circulation chamber 31 .

The flat-shaped fine filter 32 also enables the second partial flow US2 of the circulation flow US to be led from the washing compartment into the circulation compartment 31 . Here, too much dirt is largely prevented from entering the circulation chamber 31 . When viewed from the inside out, only the first partial flow US1 of the circulating flow US travels through the centrally arranged coarse filter 34, through the fine filter 27 arranged centrally with the coarse filter and radially spaced apart, and through the surrounding fine filter The concentrically arranged microfilter cartridge 28 of the filter enables a stronger circulation flow US and thus has a positive effect on the cleaning action of the dishwasher. Compared with comparable existing dishwashers, the flat fine filter 32 is made larger, so that the first partial flow AS1 of the pumping flow AS and the second partial flow US2 of the circulation flow hardly or not at all It is affected by foreign matter that may be deposited on the upper side of the flat fine filter 32 . If desired, it may in particular be sufficient to omit the fine filter 27 and only provide a coarse filter together with the flat filter 32 and a microfilter 28 arranged at a distance from the coarse filter outside.

In order to prevent objects that cannot be pumped due to their size from entering the collection chamber 30 , approximately in the center of the filter system 20 is arranged a coarse filter with an upper section 35 and a lower section 36 . The coarse filter 34 is in this case embodied as a right cylinder. In this case, the upper section 35 extends into the washing compartment of the dishwasher, so that larger objects washed from the side by the washing liquid S are held on its outside. Objects falling directly into the interior of the coarse filter cartridge 34 from above are caught by the apparently overlapping ribs 37 . They are now located in the collection compartment 30 but the structure of the coarse filter cartridge 34 prevents them from moving in the direction of the fine filter 23 with the first partial flow US1 of the circulation flow US or with the second partial flow AS2 of the pumped flow AS. Movement in direction of discharge pump 17.

Figure 3 shows a time series A of a washing process provided in a standard dishwasher for washing regularly soiled dishes with a maximum load. The graph shows the temperature T of the washing process and the water supply WH of the dishwasher over the course of time t. The time series A proceeds in the following order: a prewashing process VG, a cleaning process RG, an intermediate washing process ZG, a rinsing process KG and a drying process TG. The prewash process VG and the cleaning process RG in this case form the cleaning phase RP of the washing process RP.

At the start of the prewash process, a specific amount of fresh water is first drawn through the dishwasher. This is represented in FIG. 3 by the curve WH lying above the zero line. This fresh water is circulated as wash liquid at low temperature in the prewash process VG. During this process, the washing liquid absorbs the dirt adhering to the items to be washed. In this case, the washing liquid is continuously guided through the filter system of the dishwasher, so that at least a large part of the dirt is retained. At the end of the prewash process, the washing liquid present is completely or partially pumped away by switching on the drain pump, which is shown in FIG. 3 as the curve WH now extending below the zero line. During the pumping of the washing liquid, as explained with reference to FIG. 2 , the filter system releases the dirt until the end of the cleaning phase RP.

At the start of the subsequent cleaning process RG, fresh water is sucked in again. Usually, fresh water is supplied to the cleaning agent in the cleaning process RG. The washing liquid present at this time is circulated so that it is guided through the filter system during the cleaning process. When the washing liquid is led through the filter system, it is heated in the heating stage HRG. The heating phase HRG ends when the temperature of the washing liquid has reached a predetermined value TRG. At this point the post-wash phase NRG begins, in which the wash liquor continues to circulate. When a certain period of time has elapsed, the post-wash phase NRG ends and the washing liquid of the cleaning process is pumped out. Thus, in a conventional standard dishwasher, the filter system releases dirt twice in the cleaning phase RP.

At the start of the subsequent intermediate washing process ZG, fresh water is sucked in again, and then it is circulated for a predetermined period of time in order to remove detergent residues from the items to be washed. At the end of the intermediate washing process ZG, this washing liquid is likewise pumped out. This intermediate wash can also be omitted if desired.

In the rinsing phase KG, fresh water is initially drawn in again and then heated until the desired temperature TKG is reached. The rinsing liquid used in the rinsing process, which is usually provided with rinsing agents, prevents the formation of spots on the cleaned dishes in this case. The heating of the washing liquid is used in this case for the purpose of heating the dishes. At the end of the rinsing process, the washing liquid is pumped away again.

In the subsequent drying process TG, the water adhering to the tableware evaporates due to the high temperature of the tableware. After a predetermined time, the entire time sequence A of the drying process and thus the washing process ends.

In contrast, FIG. 4 shows an improved time series A1' of the washing process in the case of the dishwasher according to the invention, which produces comparable cleaning effect. The improved cleaning phase RP' in this case only has a cleaning process RG'. The pre-washing process is omitted. At the start of a washing process, the washing liquid that was pumped into the washing liquid reservoir during the previous washing process is introduced into the washing compartment. In this way, it is not necessary to suck in fresh water at the beginning of the cleaning phase RG'. Therefore, the curve WH' extends along the zero line.

The heating phase HRG of the cleaning phase RG' is carried out without any particular modification. In contrast, the subsequent post-wash phase NRG' is prolonged compared to the above-mentioned post-wash phase NRG. This serves to prevent the cleaning effect of the cleaning stage RP' from being reduced due to the omission of the prewash stage. In this case, however, it is not necessary to extend the duration of the post-wash phase NRG' such that the total duration of the cleaning phase RP' is the same as that of a conventional cleaning phase RP (including pre-wash VG and cleaning process RG). The time corresponds to, but is shorter than. The reason is that the average temperature in the cleaning phase RP' is higher than the average temperature in the cleaning phase RP, which results in a greater thermal cleaning effect per unit time. Overall, the cycle time, ie the time for which the circulation pump has to be switched on, is smaller in the cleaning phase RP' than in the cleaning phase RP, which saves energy. A further energy saving is due to the fact that the discharge pump also only needs to be switched on once during the cleaning phase. Due to the dimensioning of the filter system according to the invention, it does not cause any problems for the filter system to release dirt only once in the improved cleaning phase RP'.

At the beginning of the subsequent intermediate washing process WG', new fresh water is sucked in in a known manner. However, the washing liquid of the improved intermediate washing process WG' is not pumped out at the end of the intermediate washing process ZG', but instead is pumped into the washer liquid reservoir. This wash liquor can then be used in the cleaning phase in subsequent washes.

This intermediate washing step can also be omitted if desired. The filling of the washing liquid reservoir can now take place at the end of the subsequent rinsing step.

The rinsing process KG and the drying process TG then proceed as described above. Compared with time series A of FIG. 3 , time series A' of FIG. 4 clearly enables the water consumption to be halved by the dishwasher of the invention. In the example of FIG. 3 , fresh water has to be sucked in a total of 4 times, whereas in the case of time series A' of FIG. 4 , it is sufficient to suck in fresh water twice. If for example 4 liters of water have to be sucked in per washing process, a total of 8 liters of fresh water is saved. Furthermore, in this case, due to the shortened cycle pump times in the cleaning phase RP', significant power savings can be achieved without compromising the cleaning results. Furthermore, a shortening of the overall duration of the washing process is advantageous in many cases.

In conclusion, it can be determined that the dishwasher of the present invention has a "bypass" filter system which is large relative to the load capacity of the dishwasher as is the case with standard dishwashers. This makes it possible to dispense with a separate partial washing process, such as a prewashing process, which reduces energy consumption. With the given choice of dimensions, the frequency with which cleaning of the filter system occurs in this case can be achieved without causing any problems. A "bypass" filter system for dishwashers has two fluid streams, one of which is directed through the microfilter and the other may be directed through the flat filter. In particular, the surface of the microfilter is higher than 14 cm ² per standard grid, wherein the allowable percentage of the microfilter is preferably 35%-45%, and the mesh size of the microfilter can be between 150 μm and 250 μm.

The filter system comprises in particular a centrally arranged coarse filter such as 34, a microfilter such as 28 concentrically surrounding the coarse filter and radially spaced apart, wherein the coarse filter and the microfilter are for example externally formed by a flat Filters such as 32 surround. Here, in the exemplary embodiment, the nesting of the coarse filter and the microfilter is positioned approximately centrally with respect to the filter surface. The coarse filter and the microfilter are in this case arranged approximately vertically, while the planar filters are arranged along an approximately horizontal plane. It has a surface that descends from the outside to the inside towards the coarse filter. In this way, the filter system provides two flow paths for the washing liquid when the circulation pump is operating. The first flow path passes through a coarse filter arranged centrally in a collection chamber such as 30 , through an external microfilter surrounding the coarse filter into a circulation chamber such as 31 and from there to a circulation pump. The second flow path leads directly into the circulation chamber via the flat filter, which corresponds to a "bypass", ie a bridge arranged in series, in particular a concentric nested arrangement of coarse filter and microfilter.

If desired, a first fine filter, such as 27 , can be arranged between the coarse filter and the microfilter, the meshes of which are embodied larger than those of the microfilter and smaller than those of the coarse filter.

The overall surface of the filter system, in particular of the microfilters, is increased for each standard compartment compared to the case with conventional standard dishwashers, which in particular makes it possible to dispense with prewashing and the end of the prewashing process. The usual replacement of the accompanying washing solution. This saves water and energy. In this case, for example, it is no longer necessary to pump out the dirty washing liquid by means of the drain pump, especially after the prewash process has ended. This enlargement of the filter surface makes it possible to ensure a sufficient throughflow of the filter system during circulation and to largely avoid impermissible clogging of the individual filters.

In order to reduce energy consumption, the filter system is advantageously designed with a certain amount of dirt in the cleaning phase with the prewashing process and the cleaning process, in the case of the standard dishwasher program and in the specific dishwashing In the case of a larger number of standard compartments, for example 14 standard compartments, than the number of standard compartments loaded in the actual operation of the machine, that is to say, the dishwasher operates at a lower number of standard compartments than corresponds to the size of the filter system. Operate under standard placement grids, such as 10 standard placement grids. In particular the oversized surface of the filter system makes it possible to eliminate, without causing any problems, the increase in dirt load due to the omission of the prewashing process in the cleaning phase and its final pumping process. In this way, a too severe clogging of the filter system by dirt particles, which would have too great a detrimental effect on the circulation flow of the washing liquid through the circulation pump, can be largely avoided. In particular, the surface of the filter system is oversized so that at least an increase in the dirt load of the washing liquid caused by the omission of a subsequent prewash with a pump-out process can be taken care of by the filter system. Energy can be saved by optimizing the filter system in this way.

A further reduction in the energy and water consumption of the dishwasher can be achieved through the additional use of a washing liquid reservoir.

.List of reference signs

1 dishwasher

2 washing containers

3 doors

4 washing compartments

5 upper cutlery basket

6 lower cutlery basket

7 telescopic rail

8 telescopic rails

9 fresh water supply device

10 collection pool

11 circulation pump

12 heater

13 Water Switcher

14 upper spray arm

15 lower spray arm

16 Washing fluid reservoir

17 Drain pump

18 Waste water connection

19 distribution device

20 filter system

21 Bottom of wash container

22 Controls

23 Cylindrical fine filter

24 Bottom of collection pool

25 Connecting mouth of circulation pump

26 Connection nipple for discharge pump

27 Through hole for cylindrical fine filter

28 cylindrical microfilter

29 Through holes for cylindrical microfilters

30 collection chamber

31 circulation chamber

32 flat fine filter

33 Through hole for flat fine filter

34 coarse filter

35 upper section

36 lower section

37 ribs

AW Wastewater

FW fresh water

S washing liquid

US circulation flow

AS pumped flow

D1 fine filter diameter

D2 Microfilter Diameter

D3 coarse filter diameter

RP cleaning phase

VG pre-cleaning process

RG cleaning process

ZG intermediate washing process

KG flushing process

TG drying process

HRG Heating phase of the drying process

Post-washing stage of NRG cleaning process

T The temperature of the washing process

WH water supply

TRG Maximum temperature for cleaning process

TKG Maximum temperature during flushing

Claims (14)

1. A dishwasher, in particular a domestic dishwasher (1), having: a washing compartment (4) in which a certain number of standard compartments can be loaded; and a filter system (20) , the filter system has a microfilter (28) for filtering microscopic dirt from the washing liquid circulated during the operation of the circulation pump (11) as the circulation flow (US), wherein , during the operation of the circulating pump (11), the first partial flow (US1) of the circulating flow (US) flows through the microfilter (28), the second partial flow (US2) of the circulating flow (US) is directed from the microfilter A filter (28) passing by, characterized in that ^the microfilter (28) has a filter surface of at least 14 cm ² , at most 28 cm 2 , in particular at least 16 cm ² , at most 26 cm ^{2 ,} for each standard compartment provided , and particularly preferably with a filter surface of at least 18 cm ² and at most 24 cm ² . 2. Dishwasher according to claim 1, characterized in that the microfilter (28) has through-holes (29) for the washing liquid (S) with at least 0.025 mm ² , at most 0.06 A cross section of mm ² , in particular a cross section of at least 0.03 mm ² , at most 0.05 mm ² , particularly preferably at least 0.035 mm ² , at most 0.045 mm ² . 3. The dishwasher according to any one of the preceding claims, characterized in that the ratio of the total surface area of the through holes (29) of the microfilter (28) to the total filter surface area of the microfilter (28) is At least 25%, at most 50%, especially at least 30%, at most 45%, particularly preferably at least 35%, at most 40%. 4. Dishwasher according to any one of the preceding claims, characterized in that during operation of the discharge pump (17), at least the first partial flow (AS1) of the pumped flow (AS) passes through the microfilter ( 2) wherein the flow direction of the first partial flow (AS1) of the pumping flow (AS) is opposite to the flow direction of the first partial flow (US1) of the circulation flow (US). 5. Dishwasher according to any one of the preceding claims, characterized in that a microfilter (28) is arranged between the circulation chamber (31) and the collection chamber (30). 6. Dishwasher according to any one of the preceding claims, characterized in that the filter system (20) has a fine filter (23) which, relative to the first partial flow of the circulation flow (US), ( US1 ) is arranged upstream of the microfilter ( 28 ), wherein the fine filter ( 23 ) has a filter surface at least as large as the filter surface of the microfilter ( 28 ). 7. The dishwasher according to claim 6, wherein the fine filter (23) is a fine filter cartridge (23) arranged in an upright position, and the fine filter cartridge and the microfilter cartridge (28 ) concentrically set. 8. Dishwasher according to any one of the preceding claims, characterized in that the microfilter (28) is a microfilter cartridge (28) arranged in an upright position. 9. Dishwasher according to any one of the preceding claims, characterized in that the filter system (20) comprises a further fine filter (32), the pumped flow ( The first partial flow (AS1) of AS) and/or the second partial flow (US2) of the circulating flow (US) in operation of the circulation pump (11) is extracted from the washing compartment (4) through said further fine filter Guided into the circulation chamber (31). 10. Dishwasher according to claim 9, characterized in that the further fine filter (31) is embodied as a flat filter (32) arranged in the wash compartment In the bottom (21) of room (4). 11. Dishwasher according to any one of the preceding claims, characterized in that the filter system (20) comprises a coarse filter (34), the pumped flow (AS) during operation of the discharge pump (17) The second partial flow (AS2) and/or the first partial flow (US1) of the circulating flow (US) during operation of the circulation pump (11) is guided from the washing compartment (4) to the collection via the coarse filter chamber (30), wherein a coarse filter (34) is implemented to hold back objects that cannot be pumped out by the pumped flow due to their size. 12. Dishwasher according to claim 11, characterized in that the coarse filter (34) is a coarse filter cartridge (34) arranged in an upright position. 13. Dishwasher according to any one of the preceding claims, characterized in that it is provided with a washing liquid reservoir (16) which is embodied for temporarily holding washing liquid (S ). 14. Dishwasher as claimed in any one of the preceding claims, characterized in that a washing liquid reservoir (16) is provided for the intermediate washing process (ZG) and/or rinsing process (KG) of the washing process The washing liquid (S) is received at the end and dispensed at the beginning of the cleaning phase (RP) of the subsequent washing process.

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