Dishwashing machine and method for operating the same

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DESCRIPTION

Dishwasher and procedure for its operation

The invention relates to a dishwasher with a washing tank and with devices for washing dishes by means of washing water as well as with an absorption drying device, which is conductively connected to the washing tank and conducts a absorption column with reversible dehydratable material, so that the absorption column is used for drying the dishes.

Such a dishwasher is known from EP 0 358 279 A1.

The invention also relates to a method for operating a dishwasher with at least a partial stage of the "Drying" program, in which in this partial stage of the program air is drawn from a dishwasher washing tank and / or ambient air through an absorption column with reversible dehydratable material to the wash tank and moisture is extracted through the circulation through the absorption column.

Conventional dishwashers have, as is known, a washing procedure, whose program cycle is generally constituted by at least a partial stage of the "Prewash" program, a partial stage of the "Cleaning" program, at least a partial stage of the “Intermediate washing” program, a partial stage of the “Rinse” program and a partial stage of the “Drying” program. In order to lift the cleaning effect, the washing liquid is heated in this case before or during a partial stage of the program. The washing liquid is normally heated by means of electric heaters. Different drying systems are known for drying the items to be washed in a dishwasher.

Thus, for example, a dishwasher of the type mentioned at the beginning is known from DE 20 16 831, in which air is conducted from the washing tank through a hole that can be closed in the wall of the storage tank. wash over reversible dehydratable material and from there it is led through an outward hole. Desorption of the reversible dehydratable material takes place during the dishwasher stop phase, the water vapor that appears in this case being conducted through the hole outwards. The dishwasher described is unfavorably from the energy point of view, since the regeneration of the reversible dehydratable material takes place during a phase of stopping the dishwasher, therefore in an instant, in which no partial stage of the process described is performed. beginning. Another drawback is that through the outflow of water vapor, which occurs during the regeneration of the reversible dehydratable material outwards, damage to the surrounding kitchen furniture cannot be excluded . The regeneration is linked in this case with an additional energy consumption, which is produced in addition to the need for necessary energy during the partial stages of the program.

In order to keep the energy expenditure as low as possible during the operation of a dishwasher, it is known from the document of the applicant DE 103 53 774.0 a dishwasher with a washing tank and dishwashing devices by means of washing water, which it has an absorption column connected in a conductive way with the washing tank and containing reversible dehydratable material, so that the absorption column is used, on the one hand, for drying the dishes and, on the other hand, the thermal energy used for desorption of the absorption column is used, at least in part, for heating the washing water in the washing tank and / or of the dishes.

For the solution of the same problem, the document DE 103 53 775.9 of the applicant proposes for the operation of a dishwasher to conduct air in at least a partial stage of the "Drying" program from the washing tank and / or from the air set to through an absorption column and lead it to the washing tank, so that the absorption column contains reversible dehydratable material and moisture is extracted while driving through it.

Through the use of reversible dehydratable material with hygroscopic property, for example zeolite, it is normally not necessary to heat the items to be washed in the partial stage of the program that precedes the partial stage of the "Drying" program. In this way, considerable energy savings are possible.

From EP 1 344 487 A2 a dishwasher is known, in which for drying the items to be washed the atmosphere in the dishwasher tank is heated by means of heating and in this way the items to be washed are heated in the dishwasher tank, so that the items to be washed yield moisture. This moisture then condenses on a condensing surface, so that the condensation water circulates to the sink of the dishwasher. In this case, a humidity sensor measures moisture condensation on a condensation surface of the washing chamber.

WO 98/33427 A1 publishes a dishwasher with an outlet air drying device. In this case, a temperature sensor measures a temperature drop in the wash tank, which is based on which fresh air

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cold flows to the wash tank.

The purpose of the present invention is to prepare a dishwasher and a method for its operation, with which it is possible, from an economic point of view, to efficiently clean and dry the items to be washed that are in the washing tank as well as keep as much as possible the energy expenditure involved with it.

This task is solved by means of the dishwasher according to the invention with the features according to claim 1 as well as by the methods according to the invention with the features according to claims 9 or 12 of the patent. Advantageous developments of the present invention are indicated in the dependent claims.

The dishwasher according to the invention has a washing tank and dishwashing devices by means of washing water and has an absorption drying device, which is conductively connected with the washing tank and presents an absorption column with reversible dehydratable material, so that the absorption column is used for drying the dishes, a sensor means being present, which serves for the development of a washing program for the detection of the state of the reversible dehydratable material, in order to influence the washing program cycle accordingly, the sensor means being preferably arranged in the absorption drying device. The sensor means may also be arranged outside the absorption drying device, for example at the entrance to the wash tank.

While the washing cycle of the conventional dishwasher program is subject to a time control, the invention proposes to provide a sensor means in the dishwasher, more precisely said in the absorption drying device, to adapt a partial stage of the respective program conditioned by the situation. In this way, an essential energy input is possible. This is especially the case when the dishwasher is operated, for example, only with a reduced load. Both a partial stage of the program with washing liquid (washing water) to be heated as well as a partial stage of the "Drying" program can be carried out with the same cleaning or drying action in a shorter time, so that in virtue of time saved against a control of the time program results in energy savings. The realization of the shortest times of the partial stages of the program is carried out with the help of the evaluation of the state of the reversible dehydratable material, in order to influence the cycle of the washing program, for example starting the next stage Partial program or finish the partial stage of the "Drying" program.

In an advantageous configuration, the washing program comprises at least a partial stage of the "Drying" program, in which the state of the reversible dehydratable material can be detected at least during the partial stage of the "Drying" program. and the sensor means or values ​​can be fed to a control and evaluation facility connected to the sensor means, which is installed and configured to evaluate the sensor value or sensor values ​​and to influence the wash program cycle. Since the partial stage of the "Drying" program is, in general, at the end of each washing program, the influence of the program cycle consists in a termination of the washing program.

In an advantageous configuration, the sensor means is configured as a temperature sensor. The temperature sensor is preferably arranged in such a way that it can detect the temperature value that predominates in the absorption column or that predominates in an outlet of the absorption column. This procedure is based on the recognition that the outlet temperature of the air conducted through the absorption drying device continues during drying at a characteristic temperature cycle. If the dishwasher is loaded, for example, only partially, then less water is also adhered on the items to be washed, which must be dried. As soon as the items to be washed and the washing tank are dry, this is manifested in a drop in the temperature of the air conducted through the absorption drying device. During the circulation of moist air through the absorption drying device, more precisely said through the absorption column, it is heated by virtue of the condensation energy that is released at high temperatures up to 150 ° C. As the duration of the drying process increases, the air conducted through the absorption drying device contains less and less moisture, so that a smaller heat of condensation is released. This is manifested in a fall in the temperature of the air that comes out of the absorption drying device. The temperature curve to be established in this case can be associated with the degree of drying of the items to be washed inside the dishwasher.

An influence of the washing program cycle, that is, a termination of the drying process, can thus be made possible by virtue of a value supplied by the sensing means in the control and evaluation device through a comparison with a threshold value To this end, the control and evaluation device is installed and configured to compare the sensor values ​​fed to the sensor medium with a threshold value.

An alternative configuration provides that the control and evaluation device detects the time curve of the values ​​supplied by the sensor means, and detects the gradient of the curve of the sensor values ​​or a turning point in the gradient of the curve as criterion for an influence of the wash program cycle. The device

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of control and evaluation is installed or configured in this configuration to detect the time curve of the sensor values ​​supplied by the sensor means, and to detect the gradient of the curve of the sensor values ​​or a turning point in the gradient of the curve as a criterion for an influence of the wash program cycle.

An influence of the washing program cycle can be carried out in accordance with another configuration of the invention through the configuration of the sensor means as a humidity sensor. The humidity sensor is preferably arranged in the absorption drying device in such a way that it can detect the humidity that predominates at an outlet of the absorption column in the air stream. The evaluation in the control and evaluation means can be carried out by virtue of a comparison of the value supplied by the sensor means in the control and evaluation device with a threshold value. Alternatively, the control and evaluation device can detect the time curve of the values ​​supplied by the sensor means and detect the gradient of the sensor value curve or a turning point in the gradient of the curve as a criterion for an influence of the wash program cycle.

The process according to the invention for the operation of a dishwasher, in particular a domestic dishwasher, with at least a partial stage of the "Drying" program, in which in this partial stage of the program air is conducted from the dishwasher's washing tank and / or ambient air through an absorption column with reversible dehydratable material to the washing tank and moisture is extracted from the air during driving to through the absorption column, it is characterized in that the temperature of the air conducted through the absorption column is measured at or after the absorption column, for initial the end of the partial stage of the "Drying" program depending on the value of the measured temperature or the measured temperature values.

Through this procedure it is possible to draw a conclusion about the humidity in the washing tank, so that the degree of drying can be deduced, depending on the load and regardless of the time needed so far.

In a configuration of the process according to the invention, the measured values ​​of the temperature are compared with a threshold value, to initialize the completion of the partial stage of the "Drying" program in case the value is exceeded or not reached. threshold.

In another configuration of the method according to the invention, the time curve of the measured temperature values ​​is recorded and the gradient of the temperature value curve or a turning point in the gradient of the curve of the temperature curve is used. the temperature values ​​as criteria for the termination of the partial section of the "Drying" program.

The same advantages can be achieved through a process, in which according to the invention the humidity of the air conducted through the absorption column at or after the absorption column is measured, to initiate the end of the stage Partial of the "Drying" program depending on the measured humidity value or the measured humidity values. Correspondingly, this can be initiated through a comparison of the threshold value or through the monitoring of the time curve of the humidity values.

The invention and its advantages are explained in detail below with the help of an exemplary embodiment. In this case:

Figure 1 shows a dishwasher according to the invention, and

Figure 2 shows a characteristic curve of the temperature of the air leaving an absorption drying device.

Figure 1 shows in a schematic representation mode a dishwasher 1 according to the invention with a washing tank 2, in which dish baskets 3, 4 are arranged for the ordering of items to be washed not shown.

The dishwasher 1 has an absorption column 10 containing reversible dehydratable material 11, conductively connected to the washing tank, for example zeolite, in which the absorption column 10, as explained in detail below, is used, on the one hand, for drying as well as, on the other hand, for heating circulating air, in particular as described in DE 103 53 774 and / or DE 103 53 775. The content of these requests is incorporated, as appropriate, in this application.

The washing tank 2 has an outlet 5 arranged in the embodiment described in its upper zone, with a conduit 6 towards the absorption column 10 and an inlet 8, arranged in the embodiment described in its lower zone, with a duct 7 from the absorption column 10. In the duct 6 towards the absorption column 10 a blower 9 is provided, which conducts air to the absorption column 10 from the storage tank.

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wash 2.

For desorption of the reversible dehydratable material 11, in an embodiment shown, an electric heating element 12 is arranged in the absorption column 10. To influence the cycle of the washing program, in particular in the partial stage of the " Drying ”, in addition, in the direction of the circulation at the outlet of the absorption column 10 a sensor 13 is arranged, which can be configured as a temperature sensor or humidity sensor. Alternatively, it is also possible to arrange the sensor inside the absorption column 10.

A dishwasher has, as is known, a washing procedure, whose program cycle is generally constituted by at least a partial stage of the "Prewash" program, a partial stage of the "Cleaning" program, at least a partial stage of the “Intermediate washing” program, a partial stage of the “Rinse” program and a partial stage of the “Drying” program. In accordance with the invention and in the example of embodiment explained, air is returned from the washing tank 2, on the one hand, during the partial stage of the "Drying" program through the absorption column 10 and back again to the washing tank 2. To this end the blower 9 is connected. The airway is indicated by arrows A, B and C. From the air introduced from the blower 9 through the duct 6 to the absorption column 10, all moisture is extracted from the reversible dehydratable material 11. In this case, the air is heated by the heat of moisture condensation or steam water that is released in the absorption column, thereby more advantageously increasing the moisture absorption capacity of the air. The hot air now, for example up to 40-70 ° C and very dry now arrives through the duct 7 again to the washing tank 2. The hot air introduced into this tank is completely dry and has a capacity under the higher temperatures high heating for humidity. It rises in the washing tank 2 upwards and absorbs residual moisture in the items to be washed. Now it is conducted, as already described, back to the absorption column 10.

Due to the use of reversible dehydratable material in the partial stage of the "Drying" program, it is usually not necessary to heat the items to be washed which must be treated in the partial stage of the "Rinse" program, which precedes drying. This means an essential energy saving. Through the heating of the air, the moisture absorption capacity of the air is increased in each circulation through the absorption column 10, which leads to the improvement of the drying result and the shortening of the drying time.

For desorption of the reversible dehydratable material, air is redirected, in the example of embodiment explained, from the washing tank 2 during a partial stage of the program with washing liquid that must be heated or in certain circumstances already hot, preferably during the partial stage of the "Cleaning" and / or "Prewash" program, in the embodiment described through the absorption column 10 and back to the wash tank. To this end the blower 9 is connected, as already explained above. The airway is indicated by arrows A, B and C. In addition, heating 12 is switched on, to effect desorption of reversible dehydratable material 11.

As is known, reversible dehydratable material 11 is heated for desorption at a very high temperature. In this case, the accumulated liquid comes out as hot steam. Through the air duct by means of the blower 9 through the conductors 6 and 7 in accordance with the air path of the arrows A, B and C, the steam is conducted to the washing tank 2 and is also heated the air in the wash tank. The introduction of hot steam and hot air into the washing tank 2 during the partial stage of the "Cleaning" program in the washing tank is largely sufficient to sufficiently heat the washing water and / or the dishes. In this way, additional heating is largely suppressed and the energy used for desorption, except for the reduced energy, which is needed to overcome the adhesion forces between water and reversible dehydratable material, can be used almost constantly for heating of washing water and / or dishes. In this way, in addition to saving energy, efficient cleaning of the items to be washed is also required.

The energy consumption during the partial stage of the "Drying" program is caused by the operation of the blower for the conduction of the air from the washing tank 2 through the absorption column 10 and again back to the storage tank. to wash. In this case, the air outlet temperature from the absorption column follows a characteristic temperature curve, which is represented in Figure 2. By virtue of the first very humid air, conducted through the absorption column 10, a very high condensation heat appears, when wetted, through which the reversible dehydratable material is heated and, therefore, the air conducted through it at temperatures up to approximately 160 ° C. With the progress of the time of the partial stage of the "Drying" program, the air conducted through the absorption column 10 dries more and more, so that the heat of condensation that appears in the reversible dehydratable material is reduced, and the air conducted through the absorption column has a lower temperature.

In this case, it has been proven that a certain temperature can be associated with a certain degree of drying. In the present embodiment, a temperature of about 57 ° C corresponds to a drying rate of about 98%. This characteristic temperature, which can be used as a threshold value for comparison with the temperature values ​​calculated by the temperature sensor, depends on

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the practice of how the absorption column is configured. Possible influence quantities are in this case the resistance of the circulation of the absorption column, which essentially depends on the diameter of the zeolite balls and the geometric measurements of the absorption column.

Figure 2 shows the curves of the temperature of the air leaving the absorption column, on the one hand for the case of a normal load (Case 1) and, on the other hand, for the case of a reduced load (Case two). In this respect it is clear that in the case of a reduced dishwasher load, the temperature falls more strongly after reaching its peak value, so that the threshold value (dashed line at approximately 57 ° C) has been reached at an earlier time. As a result, this means that the drying process in a lightly loaded dishwasher has finished faster than in a normal loaded dishwasher.

In addition to a comparison with the threshold value, the gradient of the measured temperature curve can also be used as a criterion for the termination of the partial stage of the “Drying” program. Otherwise, it is possible to detect a characteristic turning point in the temperature curve.

In another variant not shown, to influence the cycle of the washing program, the measured humidity is used instead of the temperature. The procedure corresponds in this case, in principle, to the one just described.

An additional reduction of the drying time is achieved when in the partial stage of the program, which precedes the partial stage of the "Drying" program, usually the rinse, a heating of the treatment liquid or the article to be washed has taken place. The temperature curve in the partial stage of the "Drying" program then follows a higher gradient, which can also accelerate the drying process.

With the present invention it is possible to economically operate a dishwasher of the type described, efficiently dry the article to be dried and keep as much as possible the energy expenditure involved therewith by virtue of the reduction of time.

List of reference signs

1 Dishwasher 2 Washing tank 3 Crockery basket 4 Crockery basket 5 Outlet 6 Duct 7 Duct 8 Inlet 9 Blower 10 Absorption column 11 Reversible dehydratable material 12 Heating element 13 Sensor medium A, B, C Airway