EP2352410B1 - Dishwasher and related method for heating the liquid thereof - Google Patents

Description

The invention relates to a method for operating a dishwasher, in particular a domestic dishwasher, according to the preamble of patent claim 1.

Dishwashers are known to go through wash programs comprising a plurality of program steps, such as e.g. Pre-rinsing, cleaning, rinsing, rinsing and drying the cleaned items. During some of the program steps, e.g. prewashing or cleaning, heating liquid with a heating means designed as a water heater, which can be the same amount of liquid which is heated twice with the water heater, or two quantities of liquid. The heating with a water heater allows a rapid heating of the liquid, but this exposes particularly sensitive items particular loads.

An alternative way to heat the rinsing liquor in a dishwasher. describes the DE 10 2005 004 089 A1 , There it is proposed to use the heated by a heater for the desorption of a reversibly dehydratable material also to heat the rinse water, the heater is also operated after reaching the desorbed state of reversibly dehydratable material until the nominal temperature of the rinse liquor is reached ,

In the DE 103 53 774 A1 it is stated that the air heating of the sorption drying system of a dishwasher is largely sufficient to sufficiently heat the rinsing liquor and / or the dishes during the "cleaning" part program step.

In the older one. subsequently published WO 2010/010013 A 1 is a rinsing method for a dishwasher, which in particular has a drying means having a reversibly dehydratable drying means, for suppressing undesired deposit formation indicated. In this case, in at least one partial program step of a first rinse cycle, rinse liquid is heated in a first operating mode to a first temperature. After a predetermined number of times in the first mode operated rinses and / or depending on process parameters of previous rinses at least one rinse is operated in a second mode, while the rinsing liquid is heated to a second, compared to the first temperature elevated temperature. The partial program step which can be operated in the first or second operating mode is preferably a cleaning step in which the first and second temperature respectively correspond to the cleaning temperature. The second temperature of the partial program step operated in the second operating mode is expediently increased in such a way that grease deposits and / or impurities in the hydraulic system of the dishwasher are dissolved and in particular the elevated temperature is of the order of 60 to 65 ° C. In the drying step, the air in the washing container is passed through the drying means having a reversibly dehydratable drying agent back into the washing compartment. In a regeneration process, the amount of water stored in the desiccant is returned as heated steam in the washing container, which heats the rinsing liquid to a temperature T1, in particular in the cleaning step. The rinsing liquid heated to the temperature T1 is heated further to the first or second cleaning temperature by means of a water heater provided in the rinsing liquid circuit.

The invention has for its object to reduce the thermal loads, in particular of sensitive items to be washed.

The solution of the object of the invention is based on a method for operating a. Dishwasher, in particular a domestic dishwasher, in which a liquid is heated with a first heating means to a final temperature.

According to the invention, it is provided that with a second heating means, the liquid is heated to a low temperature, which is below the final temperature. In this case, the first heating means is a water heater which is designed as a continuous flow heater for heating circulated liquid and / or can be integrated in a circulating pump. Thus, an adjustment of the heating power is possible by alternating operation, in particular to gently heat delicate items to be washed.

According to the invention, it is provided that an air heater is used as the second heating means. By the air heating takes place in particular a gentle heating of the items to the first, low temperature, without the items to be washed special thermal Is exposed to stress. In this case, the air heater is designed such that it is able to expel fluid from a desiccant as part of a sorption drying system at the same time.

According to the invention, it is provided that a water heater is used as the first heating means. This allows a particularly rapid heating to the second, higher end temperature and thus a shortening of the total program duration of a wash program.

According to a further development it is provided that the first, low temperature is selected substantially between 30 to 50 ° C, in particular between 40 to 45 ° C. This ensures a short heating time and thus no extension of the total program duration of a wash program.

According to a further development it is provided that the second, higher end temperature is selected substantially between 45 to 80 ° C, in particular between 55 to 75 ° C. This ensures that cleaning agents can develop their optimum effect and thus ensure optimum cleaning results.

According to a further development, it is provided that the desorption of the first, low temperature at least partially desorption of a reversibly dehydratable dry material (ZEO), in particular zeolite, a sorption drying system is effected. This ensures that the desorption process is carried out by means of the air heating at the beginning of a heating phase of a liquid. At this time, the temperature is lowest in comparison with the subsequent program steps of a washing program and thus the moisture absorption capacity of the air in the interior of the dishwasher is greatest. This ensures a particularly effective desorption process. Upon reaching the first, low temperature, the desorption process can be completed. However, it is also possible that upon reaching the first, low temperature only a partial desorption was achieved and a complete desorption is achieved at a later time of a Spülprogrammdurchlaufs or during a further subsequent Spülprogrammdurchlaufs.

According to the invention, it is provided that during a program step cleaning with detergent addition and cleaning liquid only by means of the air heater first to the first, low temperature, and then only with the water heater to the second, higher Final temperature is heated. This allows a particularly energy-efficient cleaning of items to be washed. In particular, it can be provided to heat liquid only during the program step, which further reduces the energy requirement.

According to the invention, a draining phase is provided between a program step rinsing and a program step drying.

According to a further development, it is provided that, during a program step, pre-rinse with cleaning action without detergent addition, liquid is heated to the first, low temperature. In this way, the cleaning effect during the program step pre-rinsing and thus the entire washing program can be significantly increased, at which time the moisture absorption capacity of the air located in the interior of the dishwasher is greatest, so that a particularly effective desorption is guaranteed.

According to a further development, it is provided that during a program step rinsing with rinse aid liquid is heated to the first, low temperature. This makes it possible, for example, to complete a desorption process begun in a previous program step, or to perform a complete desorption process. Also at this time, the air inside the interior of the dishwasher is due to the liquid changes, i. Abpumpvorgänge and refills with approximately 15 ° C warm water from a home-side supply system compared to other times a wash program is relatively cold, so that an efficient Desorptionsvorgang is guaranteed.

Furthermore, the object of the invention is achieved by a dishwasher, in particular household dishwasher, according to claim 7.

Further developments of the dishwasher according to the invention are specified in the subclaims.

The invention and its development will be explained in more detail with reference to drawings.

Fig. 1

eine schematische Darstellung eines Ausführungsbeispiels einer erfindungsgemäßen Geschirrspülmaschine mit einem Sorptionstrocknungssystem,

Fig. 2

eine schematische Darstellung des Temperaturverlaufs während eines ersten Ausführungsbeispiels eines erfindungsgemäßen Spülprogrammdurchlaufs,

Fig. 3

eine schematische Darstellung des Temperaturverlaufs eines weiteren, zweiten Ausführungsbeispiels eines erfindungsgemäßen Spülprogrammdurchlaufs, und

Fig. 4

eine schematische Darstellung des Temperaturverlaufs eines weiteren, dritten Ausführungsbeispiels eines erfindungsgemäßen Spülprogrammdurchlaufs.

Show it:

Fig. 1

a schematic representation of an embodiment of a dishwasher according to the invention with a Sorptionstrocknungssystem,

Fig. 2

a schematic representation of the temperature profile during a first embodiment of a Spülprogrammdurchlaufs invention,

Fig. 3

a schematic representation of the temperature profile of a further, second embodiment of a Spülprogrammdurchlaufs invention, and

Fig. 4

a schematic representation of the temperature profile of another, third embodiment of a Spülprogrammdurchlaufs invention.

It is going on first FIG. 1 Referenced.

A dishwasher GS designed in the present exemplary embodiment as a domestic dishwasher has an interior space IR serving as a washing container, which can be opened or closed for loading and unloading by means of a door (not shown) pivotably hinged to the dishwasher GS. Dishwashing baskets GK are provided in the interior IR of the dishwasher GS for receiving items to be cleaned, which can be pulled out of the interior IR of the dishwasher GS in order to facilitate loading and unloading.

In order to clean the items to be stored in the crockery baskets GK, means for supplying items to be washed with liquid are provided in the interior IR of the dishwasher GS as spraying arms SA, wherein the liquid may, for example, be filled with water. can act with detergents or with rinse aid added water, so as to effect a cleaning effect or streak-free drying. The liquid flowing down from the items to be washed collects in a pump sump PS, which is arranged in the bottom area of the interior IR of the dishwasher GS.

The spray arms SA are fluidly connected via a supply line ZL with a circulation pump UP, which is arranged in a floor assembly BO below the interior IR of the dishwasher GS next to other components of the dishwasher. During operation, ie when the circulation pump UP is running, the circulation pump UP sucks the liquid accumulated in the pump sump PS and delivers it through the supply line ZL to the spray arms SA. In order to heat the liquid circulated by the operation of the circulating pump UP, the circulating pump has an integrated water heater WZ for heating the liquid. Alternatively, in addition to the circulation pump UP, a separate instantaneous water heater or another water heater may be provided. For emptying the interior IR of the dishwasher GS, a drain pump LP is provided, which is also in fluid-conducting connection with the pump sump PS and can be connected to a disposal line EL to a house-side sewage disposal network.

Furthermore, the dishwasher GS has a sorption drying system, with which in the dish racks GR arranged and cleaned items can be dried at the end of a Spülprogrammdurchlaufs. For this purpose, a sorption SB is provided in the bottom assembly BO, which is air-conductively connected to an inlet EI via an air channel LK, wherein a fan LT is provided for generating a forced flow. In order to recirculate the air sucked in through the inlet EI and conveyed by the ventilator LT into the sorption container back into the interior IR of the dishwasher GS, an outlet opening AU is provided in the bottom area of the interior IR dishwasher GS.

In order to effect a drying of cleaned items to be washed, air is sucked in from the interior IR of the dishwasher GS by the fan LT, passed through the sorption container SB and again through the discharge opening AU back into the interior IR of the dishwasher GS. In order to dry the circulated air in this case, a drying agent for carrying out an exothermic drying is provided in the sorption container SB. This is a reversibly dehydratable drying material, eg zeolite, which absorbs water due to its hydroscopic property, heat energy being released at the same time. By this released heat energy heating of the circulating air is effected, which at the same time increases the moisture absorption capacity of the circulating air. At the end of a drying process, an amount of liquid is stored in the drying material ZEO.

In order to restore the capacity of the drying agent ZEO for a new wash program run, an air heater HZ is provided, which is arranged in the present embodiment in the sorption SB. However, it is also possible to arrange an air heater outside the sorbent tank SB, e.g. in the air passage LK to cause heating of the conveyed into the sorbent SB air. To drive off the amount of liquid stored in the drying material ZEO, an air flow generated by the fan LT is heated, so that the drying material ZEO can be heated to temperatures at which the amount of water stored in the drying material ZEO can be released again.

It will now be added to the FIGS. 2 to 4 Referenced.

Dishwashers GS continuous for cleaning and drying of items to be cleaned, wash programs, which consist of a plurality of program steps, which are passed through successively. Such a program may consist of the program steps pre-wash V, cleaning R, intermediate rinsing Z, rinsing K and drying T, with individual program steps such. B. the pre-wash V or intermediate rinse Z can also be hidden, while it is also conceivable to pass through individual program steps repeatedly, such as the intermediate rinsing Z. During the pre-rinsing V, for example, ware is charged with water without the addition of detergents, this either with unheated water or with heated water by means of a heater. For this purpose, water can be used that has been stored in a water tank (not shown). Such a water tank can be in heat-conducting connection with the surroundings of the dishwasher so that liquid stored in the water tank, such as water from a home-side supply system, can warm up to room temperature. In the cleaning step R, cleaning of items to be washed takes place by application of detergent-added water, ie during the cleaning stage a detergent addition takes place. Furthermore, a heating of the liquid, so as to increase the cleaning effect of the cleaning agent. In this case, the cleaning step R is composed of a heating phase P1, P2, in which the liquid is heated in the dishwasher GS by means of heating until a predetermined maximum temperature is reached and a subsequent Nachwaschphase together, while the heater is turned off, the slowly cooling liquid by the circulating pump UP is circulated. In the program step intermediate rinsing Z, the items to be washed with liquid applied to so as to promote debris from the dishwasher GS. The next step in the program is rinsing K in preparation for the program step drying T, in which water mixed with rinse aid is circulated by means of the circulation pump and applied to the now cleaned items via the spray arms SA. Finally, the program step drying T, in which the wash ware is no longer charged with liquid, but by operation of the fan LT through the interior IR of the dishwasher GS and the sorbent SB circulating air flow is generated. A complete or at least partial fluid change can be carried out between the individual program steps, ie the dishwasher GS is emptied by means of the drain pump LP and the disposal line EL and refilled again by a supply line (not shown) making a connection to a house-side supply system.

In the rinse program according to FIG. 2 takes place only in the program step cleaning R heating of liquid. In this case, starting from a starting temperature T0, during a first phase P1, the liquid circulated by the circulation pump UP is heated by the air heater HZ in the sorption tank SB to a maximum temperature T1, wherein the fan LT at the same time circulates through the interior IR of the dishwasher GS air flow generated. The air heater HZ heats the drying material ZEO into the sorption container SB to temperatures at which the amount of water stored in the drying material ZEO is expelled from the drying material ZEO and conveyed through the outlet opening AU into the interior IR dishwasher GS. Due to the effect of the air heater HZ this amount of liquid is heated and thus causes by mixing the already circulated with the circulation pump UP liquid heating of the total amount of liquid in the interior IR dishwasher GS. Characterized in that by means of the air heater HZ during the program step cleaning R heating up to the first temperature T1, it is ensured that the dry material ZEO can be reliably and completely desorbed by the circulation of relatively cold and dry air from the interior IR dishwasher GS , Instead of a rigid rinsing program sequence in which a desorption process is carried out in a first program section, in which a heating of liquid takes place, it can also be provided in an alternative embodiment to evaluate the parameters influencing the desorption process for determining the time for performing the desorption. This can be the air temperature and the water inlet temperature. For example For example, a desorption process may be performed in a program step of cleaning or rinsing or, if appropriate, during the pre-rinse program step.

During desorbing by means of the air heater HZ, the blow-out opening AU is cooled in the interior IR dishwasher GS, so as to ensure that due to the heating power of the air heater HZ no excessive heating of the blow-out opening HZ with overheating damage occurs.

For this purpose, during operation of the air heater HZ, i. e.g. during the phase P1, the circulation pump UP is operated so that liquid is conveyed from the pump sump PS through the supply line to the spray arm SA by the circulation pump. As a result, the spray arms SA are set in rotation and cause by spraying the exhaust opening AU, in particular a cap covering the exhaust opening AU with liquid, a cooling thereof.

In a next phase P2 of the program step cleaning R, the amount of liquid is heated from the first temperature T1 to the second temperature T2 by means of the water heater WZ.

In order to increase the cleaning effect during the program step cleaning R, it is provided by increasing the rotational speed of the circulation pump UP to increase the spray pressure of the water jets emerging from the spray arm SA. For this purpose, during the program step cleaning R during the Nachwaschphase NA, the volume of liquid circulated by means of the circulation pump UP is increased by a refilling step, for example. At time t1 (see. FIG. 2 ) and then increases the speed of the circulation pump UP, for example, continuously, until the circulation pump again runs under runout condition, ie, during operation no air bubbles sucks, which reduces the flow rate of the circulation pump UP and leads to an undesirable noise. This makes it possible to take into account the amount of liquid released during the desorbing, which was stored in the drying material ZEO, in the dimensioning of the amount of liquid to be replenished and thus to reduce the total water requirement with improved cleaning performance.

Between the program step rinsing K and the program step drying T a dripping AB is provided (see. FIG. 2 ), while adhering to the cleaned items Liquid, ie, water added with rinse aid, can drain from the washware due to gravity and can collect in the pump sump PS of the interior IR of the dishwasher GS. As a result, the amount of liquid to be absorbed by the sorption drying system is reduced and thus the duration of the program step drying T.

Before this dripping phase AB, i. at the end of the program step rinsing K, a pumping down process takes place in which the liquid mixed with rinse aid is conveyed by means of the drain pump LP through the discharge line EL into a house-side wastewater disposal system. This is followed by the Abtropfphase AB, during which neither the circulation pump UP nor the drain pump LP and not the fan LT or one of the heaters HZ, WZ are in operation. After expiration of this dripping AB, the program step drying T starts by putting the fan LT, so that a circulating through the interior IR of the dishwasher and the sorbent SB air flow is generated to dry the cleaned items in the baskets GK. At the end of the program step drying T, a further pumping down by means of the drain pump LP, by means of which a remaining amount of liquid from the dishwasher GS is conveyed through the discharge line EL in a house-side sewage disposal system. Alternatively, it can also be provided to perform a further pump-down process additionally or alternatively at the beginning of the program step drying T.

In the washing program according to FIG. 3 and 4 For this purpose, by means of the air heater HZ liquid is heated starting from a start temperature T0 during a phase P1 'to a temperature T1' in which as described above by means of the fan LT by a the interior IR of the dishwasher GS and the sorbent SB circulating air flow is generated. After reaching the temperature T1 ', the air heater HZ is deactivated. At this time, the drying material ZEO is not completely desorbed, ie in the drying material ZEO a residual amount of water is stored. To expel this amount of residual water from the drying material ZEO and thus have a again fully water-absorbent drying material ZEO at the beginning of the program step drying T available, in the subsequent program step cleaning R first heated the liquid by means of the air heater HZ to a temperature T1 and then by operating the Water heating to the temperature T2 heated. That is, the desorption phase of the drying agent ZEO in Sorption tank SB is divided into two parts in this embodiment and is distributed over two program steps, namely the program step pre-wash V and the program step cleaning R.

In order to increase the cleaning effect by further increasing the temperature, another phase P3 (cf. FIG. 3 ), while the water heating WZ is used to further heat the liquid to a temperature T3.

In order to improve the drying result at the end of the program step drying T, in the embodiments according to FIGS Figures 3 and 4 provided that during the rinse step K, a heating of the liquid takes place. For this purpose, during a phase P4 by means of the water heater WZ liquid, which is water or water mixed with rinse aid, is heated to a temperature T4. Alternatively, instead of Wasserheizurig also the air heater HZ be used to complete, for example, so far not completed during the program desorption. In addition, during a further phase P5, a further heating of the liquid to a temperature T5 can take place in order to improve the drying with the sorption drying system.

LIST OF REFERENCE NUMBERS

FROM

dripping

AU

Ausblassöffnung

BO

bottom assembly

EGG

inlet

EL

disposal line

GK

dish rack

GS

dishwasher

HZ

air heating

IR

inner space

LK

air duct

LP

Drain pump

LT

Fan

N / A

post-wash

P1 '

Phase 1 '

P1

Phase 1

P2

Phase 2

P3

Phase 3

P4

Phase 4

P5

Phase 5

PS

sump

SA

spray arm

SB

sorption

t1

Nachfüllzeitpunkt

T0

starting temperature

T1 '

temperature

T1

temperature

T2

final temperature

T3

temperature

T4

temperature

T5

temperature

UP

circulating pump

WZ

water Heating

ZEO

drying material

ZL

feed

Claims (4)

1. Method for operating a dishwasher (GS), in particular a domestic dishwasher, in which a liquid is heated to a final temperature (T2) using a first heating medium,
   wherein with a second heating medium the liquid is heated to a low temperature (T1, T1') which lies below the final temperature (T2), wherein an air heater (HZ) is used as a second heating medium, said air heater being embodied such that as part of a sorption drying system it is capable of heating up air and at the same time driving liquid out of a drying medium (ZEO), wherein a water heater (WZ) is used as a first heating medium, and wherein a draining phase (AB) is provided between a rinsing (K) program step and a subsequent drying (T) program step,
   characterised in that during a cleaning (R) program step with the addition of detergent and a cleaning effect, liquid is only firstly heated by means of the air heater (HZ) to the first, low temperature (T1) and is then only heated to the final temperature (T2) by means of the water heater (WZ).
2. Method according to claim 1, characterised in that the first, low temperature (T1, T1') is essentially selected between 30 to 50°C, in particular between 40 to 45°C.
3. Method according to claim 1 or 2, characterised in that the final temperature (T2) is essentially selected between 45 to 80°C, in particular between 55 to 75°C.
4. Method according to at least one of claims 1 to 3, characterised in that by heating to the first, low temperature (T1, T1') a desorption of a reversibly dehydrateable drying material (ZEO), in particular zeolite, of a sorption drying system is effected at least partially.

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