DE102012202738B4 - Dishwasher with an air heater - Google Patents

Abstract

A dishwasher, in particular household dishwasher (1), with a control device (14) for influencing, in particular controlling and / or regulating, a rinse cycle for cleaning items to be washed by means of a rinsing liquor (S), with a rinsing chamber (2) for receiving the items to be washed is proposed during the rinse cycle, with an air heater (6), in particular for heating the rinsing liquor (S) and / or drying the dishes by means of an air flow (LS), which a fan (7) for generating the air flow (LS) and a heater (8 ) for heating the air flow (LS) and with a first sensor (17) for generating a first measurement signal (M1) correlating with a temperature (T3) of the air flow (LS) downstream of the heater (8), wherein a second sensor (17) 19) is provided for generating a with a temperature (T2) of the air flow (LS) upstream of the heater (8) correlating second measuring signal (M2), wherein the control means (14) to Bil tion of a relation, in particular difference (D) from the first measurement signal (M1) and the second measurement signal (M2) and for influencing the Luftheizeinrichtung (6) based on the relation, in particular difference (D) is formed.

Description

The present invention relates to a dishwasher, in particular a domestic dishwasher, with a control device for influencing, in particular control and / or regulation, a rinse cycle for cleaning items by means of a rinsing liquor, with a rinsing chamber for receiving the items to be washed during the rinse cycle, and with an air heater, in particular for heating the rinsing liquor and / or drying the items to be washed by means of an air flow, which comprises a fan for generating the air flow and a heater for heating the air flow.

From practice z. Example, a dishwasher is known in which overheating of the air heater is prevented by means of a temperature controller to which the first measurement signal is supplied as a controlled variable. The temperature controller is a so-called two-point controller that alternately switches the power supply on or off. The regulation of the air heater takes place via a variable timing of the power supply.

In addition, the air heater is equipped with a fuse, which permanently interrupts the voltage supply of the air heater when a critical temperature is reached by melting. To restart the dishwasher then replacement of the fuse is required.

In addition, clothes dryers are known which are equipped with a Sorptionstrocknungseinheit. The sorption drying unit serves to dry air, which is then passed through the laundry to dry it. The Indian DE 10 2010 002 086 A1 described dryer may also have in its adsorber, in which there are an adsorber and an adsorber, a sensor system. This may preferably comprise a temperature sensor and / or a moisture sensor for determining the temperature and / or the humidity of the process air conveyed through the adsorber unit by means of a blower. An evaluation unit evaluates the signals of the sensor system so that a control device of the dryer can control the adsorption phases and desorption phases for the adsorber unit in terms of design, duration and number.

The DE 10 2006 042 486 B3 relates to a method for cleaning and drying items in a dishwasher with the program sections cleaning, rinsing and drying. In this case, the environmental variables influencing the drying result are recorded and, depending on this, the amount of rinse aid used in the rinse aid program section and / or the final temperature of the rinse aid rinse used in the rinse program section are set as parameters influencing the drying result. When using an air-to-water heat exchanger, the environment variable is the temperature of the cooling water, and when using an air-to-air heat exchanger, the ambient temperature is detected at the installation location of the dishwasher. The measurement of the air temperature takes place at the beginning of the cleaning program. For temperature detection, at least one sensor is used, with which in addition to the air temperature and the liquor temperature is measured, wherein the determination of the air temperature takes place at a time at which the sensor is not yet charged with cleaning liquor.

The object of the present invention is to improve a dishwasher with an air heater.

The object is achieved by the following dishwashing machine according to the invention: The dishwasher according to the invention, in particular domestic dishwasher, has a control device for influencing, in particular control and / or regulation, a wash cycle for cleaning wash ware by means of a wash liquor, a wash chamber for holding the wash ware during the wash cycle, and an air heater, in particular for heating the rinsing liquor and / or drying of the items to be washed by means of an air flow on. The air heater comprises a fan for generating the air flow and a heater for heating the air flow. Further, a first sensor for generating a correlated with a temperature of the air flow downstream of the heating first measurement signal is provided. In the dishwasher according to the invention, a second sensor is additionally provided for generating a second measuring signal correlating with a temperature of the air flow upstream of the heating. In this case, the control device is designed to form a relation, in particular difference, from the first measurement signal and the second measurement signal and to influence the air heating device on the basis of the relation, in particular difference.

The dishwashing machine according to the invention can be provided in particular for items to be washed, in particular dishes to be washed, introduced into a treatment space, also called a rinsing chamber, and cleaned in a rinsing process, which is also called rinsing, with the aid of rinsing liquor and then dried.

Under a rinsing liquor is understood to mean a liquid which is intended to be applied to the items to be washed in order to clean this and / or treat it in a different way. So For example, the rinsing liquor may also be provided for heating the items to be washed, which is customary, for example, during a rinsing step. A rinse liquor usually consists to a large extent of water. Depending on the operating phase of the dishwasher, the rinsing liquor can be enriched with cleaning agents, with cleaning aids, such as, for example, rinse aid and / or with dirt that has been removed from the items to be washed.

The dishwasher according to the invention has a control device for the automatic influencing or control, in particular control and / or regulation, of operating sequences of the dishwasher. For this purpose, the control device can be designed as so-called sequence control, in particular as electronic sequence control.

At least one wash program for performing a wash cycle for washing items to be washed, in particular for washing dishes, is deposited in the control device. Advantageously, several wash programs are provided, one of which can be selected and started by the operator. This makes it possible to adjust the sequence of a rinse cycle in particular to the load, to the type of loading, to the degree of soiling of the items to be washed and / or to the desired duration of the rinse cycle.

An exemplary sequence of such a rinse cycle for cleaning the items to be washed several rinses, namely in this order at least one pre-rinse for pre-cleaning items, at least one cleaning cycle for thorough cleaning of items, at least one intermediate rinse for removing soiled rinse from the dishes and at least one rinse Preventing stains on the items to be washed and / or preparing a drying cycle in which the items to be washed are each treated with washing liquor. These partial rinses are therefore referred to as water-carrying partial rinses. Furthermore, the exemplary drain provides a partial wash cycle following the water-conveying partial wash cycles for drying the cleaned wash ware, namely a drying cycle.

The pre-rinse cycle is used in the example, especially the removal of coarse dirt from the dishes. The purpose of the subsequent cleaning cycle is to completely remove contaminants from the items to be washed, for which purpose a rinsing liquid added with cleaning agent can be used. The now performed intermediate rinse serves in particular for the removal of detergent residues, which adhere to the items to be washed. The subsequent rinse cycle is in particular to avoid stains on the items to be washed, which could be caused by dissolved substances in the water, such as salt and / or lime. For this purpose, the rinsing liquid can be mixed with rinse aid during the rinse cycle. However, there are also dishwashing programs in which the pre-wash cycle and / or the intermediate rinse are partially or completely omitted. Other sequences of liquid-carrying Teilspülgängen and the final drying cycle can be useful for each rinse.

Usually, a predetermined amount of liquid is introduced into the rinsing chamber at the beginning of a water-carrying partial rinse cycle, so as to form a rinsing liquor for the respective partial rinse cycle. The rinsing liquor of the partial rinse cycle is typically removed from the rinsing chamber at the end of the partial rinse cycle. In this case, the temperature of the introduced rinsing liquor is lower in many cases than is expedient for the respective partial rinse cycle. Therefore, a modern dishwasher usually has at least one heating device for heating a rinsing liquor. Conventionally, such a heating device is designed as a water heater, in which the heat is transferred by direct thermal contact of a preferably electric heater, in particular by heat conduction, to the rinsing liquid. In contrast, the dishwasher according to the invention alternatively or additionally to a heating device designed as an air heater, in which the heat is transmitted by means of an air flow of a preferably electric heating, in particular by convection heat, to the rinsing liquor.

The air heating device, in particular for heating the rinsing liquor and / or drying the items to be washed by means of an air flow, the dishwasher according to the invention has a fan for generating the air flow and a heater for heating the air flow, wherein the fan and / or the heating influenced by the control device are. By "influenceable" is meant a controlling and / or regulating influence possibility. The air heater further comprises at least one air duct into which the heater is inserted. The air duct has a first and a second air line. The second air duct (intake duct) leads, starting from the intake opening of the rinsing container, through which air is sucked from the interior of the rinsing chamber into the second air duct by means of the blower inserted there, for heating purposes. The first air line (blow-out) connects the heater with the discharge opening of the washing container, from which the air from the air duct is blown into the interior of the washing container. The heater is provided in particular in the interior of the air duct along a portion of its longitudinal course. Further, in the air duct, if necessary, a sorption container with reversibly dehydrierbarem Sorption material such. B. zeolite, can be flowed through by the air. The sorption container is preferably arranged after the heating or in the region of the heating, viewed in the direction of flow.

Furthermore, the dishwasher according to the invention comprises a first sensor for generating a first measuring signal correlating with a temperature of the air flow downstream of the heating. This means that the first sensor provides a first measuring signal which correlates with the temperature of the part of the air flow discharged from the heater and thus generally heated.

In the context of the invention, "correlate" is understood in particular to mean that a measurement signal contains information about the respective measured physical variable, ie. H. this represents. In this case, the respective physical size can be measured directly. Likewise, it can be measured indirectly by measuring a related additional physical quantity.

In addition, the dishwasher according to the invention comprises a second sensor for generating a second measuring signal correlating with a temperature of the air flow upstream of the heating. Accordingly, the second sensor provides a second measurement signal, which correlates with the temperature of the heater supplied and thus unheated part of the air flow.

Both the first measurement signal and the second measurement signal are supplied to the control device via corresponding lines, the control device for forming a relation, in particular difference, from the first measurement signal and the second measurement signal, as well as for influencing the air heater on the basis of the relation, in particular difference formed is. Influencing the air heater means influencing the actuators of the air heater, in particular the blower and / or the heater.

By now, unlike the prior art known in the art, in which only the first measurement signal is used to influence the Luftheizeinrichtung, the relation, in particular difference, from the first measurement signal and the second measurement signal is used to influence the Luftheizeinrichtung, can impending overheating of the heating better recognized and thus ultimately prevented. In addition, a false detection of overheating and thus an unnecessary response can be avoided. The reason for this is above all that the temperature of the air flow downstream of the heater depends not only on the temperatures in the area of the heating but also on the temperature of the air flow upstream of the heater. So now if the temperature of the air flow upstream of the heater is measured, it can be detected with greater certainty whether a certain temperature downstream of the heater indicates an excessive temperature in the heating or not. By forming a relation or mathematical dependency, in particular difference, from the first measurement signal and the second measurement signal, a consideration of both temperatures, namely the upstream temperature and the downstream temperature, is ensured in a simple manner.

The inventive improvement of the detection of impending overheating can be dispensed with in many cases, the use of a fuse, which simplifies the dishwasher. In addition, so the maintenance intensity can be reduced because so no fault must be replaced after a fault. In addition, in the dishwasher according to the invention, the service life of the heater and adjacent to the heating components of the dishwasher may be extended because due to the better error detection, the thermal load on the heater or the adjacent components is reduced in case of failure. The latter is based on the fact that, when the relation, in particular difference, is evaluated, an error can already be concluded with a smaller deviation from the normal value than is the case with exclusive consideration of the first measurement signal, without the risk of an incorrect identification being increased.

According to an expedient development of the invention, the air flow is guided in a closed circuit from the rinsing chamber with the aid of at least one air channel for heating and from this back into the rinsing chamber. In this way results in an effective and efficient heating of the wash liquor and / or drying of the dishes, since no heat is removed by means of the air flow to the outside.

According to an expedient development of the invention, the first sensor is arranged on a first air line (blow-out channel) for guiding the air flow from the heater to the rinsing chamber, so that the first measurement signal corresponds to the temperature of the air flow in the first air line. In this way, a largely independent of disturbance variables and therefore meaningful first measurement signal can be obtained, which reflects the temperature of the air flow downstream of the heater. In addition, there is a simple structural design of the dishwasher. The first sensor can be arranged in particular in the first air line. Alternatively, he can outside on the first Air duct be attached so that it is thermally conductively connected to the air flow.

According to an advantageous embodiment of the invention, the first sensor in the heating, in particular after the air inlet surface of the heater and before the end portion, preferably in the first two-thirds of the longitudinal extension of the heater viewed in the flow direction, arranged so that the first measurement signal of a mixing temperature Temperature of the air flow upstream of the heater and the temperature of the air flow downstream of the heater corresponds. The thus determined mixing temperature clearly correlates with the temperature of the air flow downstream of the heater, so that a relationship according to the invention, in particular difference formation is possible. In this case, the arrangement of the first sensor in the region of the heater, unlike an arrangement of the first sensor in the first air line, causes a temperature increase in the region of the heater even in the event of failure of the fan or in the event of malfunction or interruption of the operation Volumetric flow of the air flow is reliably detected, since the first sensor is acted upon not only by convection but also by heat radiation and / or heat conduction with the heat. The first sensor may in particular be arranged in an upstream or upstream region of the elongate heater downstream of its air inlet surface and in front of its end section, since in this upstream region of the heater the absolute temperatures occurring are in principle lower than at the end or immediately after heating and therefore simpler be measured as at the end or immediately after the heating and yet the heating effect of the heating on the air flow is sufficiently large for an evaluation via a temperature measurement. The first sensor is preferably provided at such a longitudinal location of the heater inserted in sections in the air duct, that from him a mixing temperature can be measured, by the heat input of the heater to the guided in the air duct through the air flow and heat transfer from the heat in the rinsing chamber during the spraying operation of the one or more spray systems sprayed rinsing liquor is effected on the sucked through the suction port of the washing container from the rinsing chamber in the air duct air flow.

Moreover, it is provided according to the invention that the second sensor is arranged such that the second measurement signal corresponds to the temperature of the rinsing liquor. If the air flow from the rinsing chamber is led to the heating, then the temperature of the rinsing water in the rinsing chamber is a measure of the temperature of the air flow upstream of the heater, since the out of the rinsing chamber and the air flow forming air in the rinsing chamber in thermal contact with the rinse liquor is. In this case, the second sensor can also be used to detect when the wash liquor has the desired temperature, so that the heating of the wash liquor can be completed on schedule, and / or when the items to be dried has the desired drying temperature.

According to an advantageous development of the invention, the second sensor is arranged on a pump chamber associated with the washing chamber. A pump pot, also called collecting pot, is understood to mean a region of the washing chamber in which the washing liquor collects due to its gravitational force, so that it transfers from there by means of a circulating pump, in particular with a heating pump which has a water heater for additional heating of the washing liquor a spray system can be applied to the dishes. In this way, a largely independent of disturbance variables and therefore meaningful second measurement signal can be obtained, which reflects the temperature of the wash liquor and thus the temperature of the air flow upstream of the heater. In addition, there is a simple structural design of the dishwasher. The second sensor can be arranged in particular in the sump. Alternatively, it may be externally attached to the sump so that it is thermally conductively connected to the rinsing liquor.

Possibly. It may also be expedient if a separate from the circulating pump water heater is provided. This can be assigned to the second sensor. In particular, the second sensor is provided in the region of this separate water heater.

According to an advantageous development of the invention, the second sensor is arranged on a circulating pump for circulating the rinsing liquid. In this way, it is ensured that the second measuring signal represents the temperature of the washing liquor in a representative manner, since it prevents the determination of the second measuring signal in a low-flow or flow-dead zone with a more or less random temperature. The circulating pump may in particular be a heating pump, which has a water heater for additional heating of the washing liquor.

According to an expedient development of the invention, a power of the heating is influenced by the control device as a function of the relation, in particular difference. In this way, overheating of the heater, in particular due to a low flow rate of the air flow, for example, caused by a Spülgut impairment of the Volume flow, effectively avoided. In addition, an overheating of the heater due to an excessive supply voltage of the heater can be avoided. This is of particular importance because the supply voltage is generally the voltage of an external power supply, for example, the voltage of a conventional home network, which may possibly be 10% to 20% above its nominal value. In addition, the supply voltage enters the power of the heater with its second power.

According to an advantageous development of the invention, a switch-off threshold is provided for the relation, in particular difference, which, if exceeded, provides for switching off the power of the heating by the control device. As a result, a threatening overheating of the heating and / or adjacent areas of the heater, but also damage to temperature-sensitive items to be washed in the washing chamber can be avoided in a simple manner.

According to an expedient development of the invention, the switch-off limit value is determined by the control device as a function of a voltage of an external voltage supply for the heating measured by means of a voltage measuring device. In this way, the detection of an impending overheating and reaction to it can be further improved because the relation, in particular difference, increases with increasing supply voltage even in normal operation.

According to an advantageous development of the invention, when the power of the heater is switched off, an error message is output via an operator interface. This allows the operator promptly take measures to eliminate any interference. For example, it may be asked to do so, dishes that the air flow over charge, d. H. impermissibly strong, obstructed, to be removed. The operator interface can be assigned to the control device and can comprise indicator lamps, light-emitting diodes, an alpha-numeric display and / or a graphic display for outputting optical messages. Furthermore, the user interface for issuing acoustic messages may include a buzzer, a loudspeaker and / or the like.

According to an expedient development of the invention, but also as an independent aspect of the invention in a dishwasher described in the introduction, a rotational speed of the fan is influenced by the control device as a function of the relation, in particular difference. In this way, a relatively complex influencing, in particular control and / or regulation, of the comparatively higher power of the heating can be supplemented or replaced. In particular, the temperature of the air flow in the region of the heating and / or downstream of the heating can thus be influenced in such a way that, given given boundary conditions, such as for a given supply voltage, a time-efficient and gentle heating of the rinsing liquor and / or drying of the ware can take place.

According to an advantageous embodiment of the invention, an increase in the speed is provided with respect to a standard speed, provided that for the relation, in particular difference, provided upper limit is exceeded. In this way, the temperature of the air stream can be lowered in a simple manner to a harmless value, if it is undesirably high, for example, at too high supply voltage. In addition, the temperatures in the heating system are lowered.

According to an expedient development of the invention, a lowering of the rotational speed in relation to a standard rotational speed is provided, provided that a lower limit value provided for the relation, in particular the difference, is not reached. In this way, for example, when the supply voltage is too low, the temperature of the air flow downstream of the heater can be increased, so that in this case, an effective heating of the wash liquor is possible because the temperature of the air flow is maintained above the temperature of the wash liquor can be. In addition or independently, sufficient drying performance can be ensured.

According to an advantageous embodiment of the invention, the air heater has a sorption with a reversibly dehydratable material, which is formed with disconnected heating for absorbing moisture (sorption) of the air flow and switched on heater for emitting moisture (desorption) to the air flow. This makes it possible to generate the air flow by means of the blower in a drying cycle and with the heating of the air heater so that the absorbed in the rinsing chamber by the air flow from the ware moisture is released from the air flow to the sorption, which the air flow and thus the dishes are dried. At the latest when the capacity of the sorption is exhausted, then a desorption of the sorption can be done by the heating of the air heater and the fan is turned on. This results in a heated air flow, which on the one hand absorbs moisture from the sorption device and on the other hand can be used for heating the rinsing liquor, for example the rinsing liquor of a cleaning cycle. In this way, an excellent Drying result can be achieved and at the same time the waste heat when desorbing the sorption advantageously used to heat rinse liquor at least one liquid-carrying Teilspülgangs the rinse cycle of a subsequent dishwashing program, so that the energy consumption of the dishwasher is reduced.

The object is also achieved by the following dishwashing machine according to the invention:
Dishwasher with a rinsing chamber having a rinsing container, with an air heater, which has at least one air duct between an intake opening of the washing and a blow-out of the Spülbehälters, wherein in the air duct, a blower for generating an air flow and a heater for heating the generated air flow are inserted, and with a control device for influencing, in particular controlling and / or regulating, at least one rinse cycle, a first sensor being provided in the region of the heating or after the heating in the outlet-side air line of the air duct for generating a first measurement signal representing a first temperature present there , and wherein a second sensor is arranged upstream of the heater in the flow direction of the air flow for generating a second measurement signal representing the temperature of the sucked from the rinsing chamber of the washing container air flow. In this case, the second sensor is formed by a temperature sensor in the liquid circuit of the dishwasher, with which the temperature of a rinsing liquor can be determined. In the case of this dishwashing machine according to the invention, it is possible to monitor better by evaluating the two measuring signals as to whether perfect operation of the air heating device is present or not. In particular, it is possible to check whether the temperatures in and / or the volume flow through the air duct are within permissible limits. For this purpose, the control device expediently determines from the first and the second measurement signal a relation or relationship, in particular its difference as evaluation signal. The control device uses this evaluation signal to control the air heater.

Expediently, the second sensor is formed by a temperature sensor in the liquid circuit of the dishwasher, with which the temperature of a rinsing liquor can be determined, which is used for a liquid-carrying partial rinsing of the respective rinse in the rinsing chamber, in particular circulated by the circulation pump of the dishwasher and / or by means of a or more spray systems is sprayed. If the rinsing liquor is circulated through the circulation pump of the dishwasher and / or sprayed by means of one or more spray systems, the temperature of the sucked air flow corresponds approximately to the temperature of the circulated and / or sprayed rinsing liquor. It is thus in addition to the liquid temperature sensor, which is provided anyway to determine the respective temperature of the rinsing, already a single temperature sensor outside the liquid circuit in the heating or after heating in the outlet side air line of the air duct sufficient to a reliable monitoring of the air heater to be able to ensure. The first sensor detects a mixing temperature resulting from the temperature of the sucked air flow and the temperature increase, which is impressed by the heating of the air flow flowing through the air duct.

Furthermore, the invention relates to a method for operating a dishwasher, in particular a domestic dishwasher, in which by means of a control means a rinse for cleaning items by a Spülflotte influenced, in particular controlled and / or regulated, wherein the items to be washed in a rinsing chamber during the rinse in which an air stream is heated by means of an air heater, in particular in which the rinsing liquor is heated by means of an air flow of an air heater and / or items to be dried by means of an air flow of a Luftheizeinrichtung, the air flow is generated by means of a fan and heated by a heater, and in which by means of a first sensor, a first measuring signal correlating with a temperature of the air flow downstream of the heating is generated. It is provided that by means of a second sensor, a second measuring signal correlated with a temperature of the air flow upstream of the heating is generated, wherein the second measuring signal corresponds to the temperature of the washing liquor, and wherein by the control means a relation, in particular difference, from the first measuring signal and formed the second measuring signal and the air heater on the basis of the relation, in particular difference, influenced, in particular controlled and / or regulated.

The method according to the invention enables an improved detection of error cases during operation of a dishwasher with an air heater.

Advantageous embodiments and further developments of the method according to the invention are explained in the description of the claimed dishwasher.

The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings. They show, in each case in a schematic outline sketch:

1 an advantageous embodiment of an inventively designed household dishwasher in a schematic side view,

2 a diagram illustrating a basic time course of a first measurement signal, a second measurement signal and a difference formed therefrom as a relation between these two measurement signals, and

3 a diagram illustrating the basic time course of the difference at different supply voltages of a heater of the air heater.

In the following figures, elements with the same function and mode of operation are each provided with the same reference numerals. In this case, only those components of a dishwasher are provided with reference numerals and explained, which are necessary for the understanding of the invention. It goes without saying that the dishwasher according to the invention can comprise further parts and assemblies.

1 shows an embodiment of a household dishwasher according to the invention 1 in a schematic side view. The dishwasher 1 has a rinse tank 2 ' with a rinsing chamber 2 on, in the not shown items to be cleaned by means of a rinsing liquid S during a rinse cycle. The in the rinsing chamber 2 introduced rinsing liquid S accumulates due to their gravity in a sump 3 which is arranged at a lower portion of the washing chamber. An example on or in the sump 3 arranged circulation pump 4 allows the flushing liquid S via a spray system 5 in the rinsing chamber 2 spray to clean and / or otherwise treat the items to be washed. At the circulation pump 4 in particular, it may be a heating pump 4 act, which has a water heater for additional heating of the rinse water. Possibly. can also be one of the circulation pump 4 be provided separate water heater.

In order to heat the rinsing liquid S to an appropriate temperature and / or to be able to properly dry the items to be washed at the end of the rinse cycle of a dishwashing program to be carried out, an air heater is provided 6 for heating the rinsing liquor S by means of an air flow LS ', which is a blower 7 for generating the intake-side airflow LS and a heater 8th for heating the air flow LS comprises. The heating system 8th includes a heating element 9 for the delivery of heat to the air flow LS. If now the blower 7 and the heater 8th are turned on, so is via a suction port 10 of the washing container 2 ' Air from the rinsing chamber 2 sucked and sucked airflow LS via a second air line or an intake passage 11 to the blower 7 , from there to the heating element 9 the heater 8th through which it is heated, and from there via a first air line or a blow-out 12 via a blow-out opening 13 of the washing container 2 ' as discharge air flow LS 'back into the rinsing chamber 2 guided. In the rinsing chamber 2 the blown-out air stream LS 'during the respective liquid-carrying Teilspülgangs the wash cycle of a dishwashing program to be carried out in thermal contact with the wash liquor S, so that it is heated. In particular, during the spraying of wash liquor S during the respective liquid-carrying partial wash cycle by the one or more spray systems 5 this is through the out of the exhaust port 13 blown air stream LS 'heated. In the exemplary embodiment, therefore, the air flow LS is in a closed circuit from the rinsing chamber 2 via the second, suction-side air line 11 to the heater 8th and over the first, exhaust-side air line 12 back to the rinsing chamber 2 guided. This is the second air line 11 and the first air line 12 a continuous air duct LK, in which the heater is preferably integrated. In this way results in an effective and efficient heating of the rinsing water S, as by means of the circulating air flow LS, LS 'no heat is removed to the outside. In addition or independently thereof, a perfect drying of the items to be washed in the drying cycle which concludes the respective rinse can be ensured by the fact that the blown-out air stream LS 'comes into thermal contact with the items to be dried.

The dishwasher 1 also has a control device 14 for the automatic influencing, in particular control and / or regulation of operating sequences of the dishwasher 1 on. The control device 14 can do this as so-called sequence control, in particular as electronic sequence control 14 be trained. In the control device 14 At least one wash program for controlling a wash cycle for washing items to be washed, in particular for washing dishes, is deposited. Advantageously, several wash programs are provided, one of which can be selected and started by the operator. This makes it possible to adjust the sequence of a rinse cycle in particular to the load, to the type of loading, to the degree of soiling of the items to be washed and / or to the desired duration of the rinse cycle.

To now also the air heater 6 to be able to influence as needed during a rinse, so to control and / or regulate is the control device 14 via a first control line 15 with the fan 7 connected so that the blower 7 by the control device 14 can be influenced. Analog is the control device 14 via a second control line 16 with the heater 8th connected, so that too the heating 8th by the control device 14 can be influenced.

Here is a first sensor 17 for producing one having a temperature T3 of the airflow LS downstream of the heater 8th provided correlating first measurement signal M1. He is particularly so in the field of heating 8th provided that it detects the increase in temperature of the air flow leaving the heating LS ', by the heating 8th caused by heat radiation and heat transfer. Here in the embodiment, the first sensor 17 in the field of heating 8th arranged so that the first measurement signal M1 of a mixing temperature T1 of the temperature T2 of the intake air flow LS upstream of the heater 8th and the temperature T3 of the airflow LS 'downstream of the heater 8th equivalent. The thus determined mixing temperature T1 clearly correlates with the temperature T3 of the heater 8th leaving airflow LS 'downstream of the heater 8th , If the rinse S in the rinsing chamber 2 circulated by means of the circulation pump of the dishwasher, in particular by means of the one or more spray systems is sprayed, the temperature T2 of the sucked air flow substantially corresponds to the temperature T2 'of the wash liquor S. In this case, the arrangement of the first sensor 17 in the area of the heating cause a temperature increase in the area of the heating 8th even with a failure of the fan 7 or is reliably detected when caused by a malfunction interruption or reduction of the volume flow of the air flow LS, since the first sensor 17 is acted upon not only by convection, but also by heat radiation and / or heat conduction with the heat. The first sensor 17 As shown, especially in an upstream area of the heater 8th That is, after the frontal air inlet surface in an area of the heating preceding the end portion of the heating 8th be arranged, since here are the absolute temperatures occurring in principle less than in the end region of the longitudinal extent of the heater, and therefore are easier to measure. The first sensor 8th detects a mixing temperature T1, which results from the temperature T2 of the intake air flow and the temperature increase, that of the heater 8th the air duct flowing through the air duct is impressed.

Alternatively, the first sensor could be 17 viewed in the flow direction after the heating 8th on or in the first air line 12 for directing the air flow from the heater 8th to the rinsing chamber 2 be arranged so that the first measurement signal M1 of the temperature T3 of the air flow LS in the first air line 12 equivalent.

The first sensor 17 is over a first measuring line 18 with the control device 14 connected such that the first measurement signal M1 from the first sensor 17 to the controller 14 is transferable. The first sensor 17 especially in the first air line 12 be arranged. Alternatively, it may be outside on the first air line 12 be attached so that it is thermally conductively connected to the air flow LS.

In addition, the dishwasher according to the invention comprises 1 a second sensor 19 for generating one with a temperature T2 of the airflow LS upstream of the heater 8th correlating second measurement signal.

In the embodiment, the second sensor 19 arranged such that the second measurement signal M2 corresponds approximately to the temperature of the wash liquor S. Since the air flow LS from the rinsing chamber 2 through the intake opening 10 of the washing container 2 ' over the second air line 11 to the heater 8th is guided, the temperature is in the rinsing chamber 2 located rinsing S a measure of the temperature T2 of the air flow LS upstream of the heater 8th because the out of the rinsing chamber 2 led out and the air flow LS forming air in the washing chamber 2 in thermal contact with the rinsing fluid S stands. This is achieved in particular by spraying the rinsing liquor S by means of the one or more spray systems 5 causes. In this case, the second sensor 19 also be used to detect when the rinse S has the desired temperature, so that the heating of the rinse S can be completed as scheduled. In the embodiment, the second sensor 19 in the rinsing chamber 2 associated pump pot 3 , namely at the in the sump 3 located circulating pump 4 arranged to circulate the washing liquid S. The second sensor 19 but could also be on an inside of the sump 3 be arranged. Furthermore, he could also on an outside of the sump 3 be attached so that it is thermally conductively connected to the rinse S In this case, it is ensured in each case that the second measuring signal M2 represents the temperature of the washing liquor S in a representative manner, since it prevents the determination of the second measuring signal M2 in a low-fluid or fluid-flow dead zone of the dishwasher's fluid circuit having a more or less random temperature ,

Alternatively, the second sensor could be 19 on the second air line 11 for directing the air flow LS from the rinsing chamber 2 to the heater 8th be arranged, so that the second measurement signal M2 of the temperature T2 of the air flow LS in the second air line 11 , ie viewed in the air flow direction of the air flow before the heater 8th , corresponds. Generalized, the second sensor is considered 19 in Flow direction of the generated air flow LS thus considered before the heating 8th in the second air line 11 positioned by the suction port 10 to the heater 8th leads.

Here is the second sensor 19 via a second measuring line 20 with the control device 14 connected such that the second measuring signal M2 from the second sensor 19 to the controller 14 is transferable.

According to the invention, the control device 14 for forming a relation, ie mathematical relationship, in particular difference, from the first measuring signal M1 and the second measuring signal M2 and for influencing the air heating device 6 based on this relation, in particular difference formed.

In the exemplary embodiment, the air heater 6 a sorption device 21 with a reversibly dehydratable material 22 on, which with switched off heating 8th for absorbing moisture (sorption) from the air flow LS and with the heating switched on 8th designed for the delivery of moisture (desorption) to the air flow LS. This makes it possible, in the drying cycle of the respective rinse the air flow LS by means of the blower 7 to generate and with switched off heating 8th the air heater 6 to guide that in the rinsing chamber 2 Moisture absorbed by the air flow LS from the air flow LS to the sorption device by the air flow LS 22 is discharged, which dries the air flow LS and thus the items to be washed. At the latest when the absorption capacity of the sorption 22 is exhausted, then a desorption of the sorption 22 done by the heater 8th the air heater 6 and the fan 7 be turned on. This creates a heated air flow LS, on the one hand moisture from the sorption 21 receives and on the other hand for heating the rinse S of a liquid-carrying Teilspülgangs such. B. a cleaning cycle can be used. In this way, on the one hand an excellent drying result can be achieved and on the other hand at the same time the waste heat when desorbing the sorption 21 be used beneficially, so that the energy consumption of the dishwasher 1 is reduced.

The supply of heating 8th takes place in the embodiment by an external power supply SV, which via a supply line 23 with the heater 8th can be connected. It goes without saying that the supply line 23 can also be provided for the supply of other energy consumers of the dishwasher. Here is a voltage measuring device 24 provided for measuring the voltage of the external power supply SV, which via a third measuring line 25 is connected to the control device such that a correlated with the voltage of the external power supply SV measurement signal to the control device 14 is transferable.

Furthermore, the dishwasher 1 of the embodiment, a user interface 26 which may have a buzzer, a loudspeaker and / or the like for the output of optical messages, indicator lamps, light-emitting diodes, an alpha-numeric display and / or a graphic display and / or for the output of acoustic messages. The user interface 26 is via a third control line 27 with the control device 14 connected, so that it can be influenced by the control device.

2 shows a diagram for illustrating a principle time course of a first measurement signal M1 of the first sensor 17 , a second measurement signal M2 of the second sensor 19 and a difference D formed therefrom. Typically, the two measuring signals M1 and M2 at the beginning of the heating of the washing liquor S have the same value AT, which corresponds to an initial temperature, which usually corresponds to an ambient temperature. The difference D is therefore initially zero. When operating the air heater 6 Then increase the value of the measuring signal M1, and slightly slower and less the value of the measuring signal M2, so that the difference D increases.

By now, unlike in the prior art known from the prior art, in which only the first measurement signal M1 for influencing the air heater 6 is used, the difference D from the first measurement signal M1 and the second measurement signal M2 for influencing the air heater 6 can be used, a threat of overheating of the heating 8th be better recognized and ultimately prevented. In addition, a false detection of overheating and thus an unnecessary response can be avoided. The reason for this is mainly that the temperature T3 of the airflow LS downstream of the heater 8th not only from the temperatures in the area of heating 8th but also from the temperature T2 of the air flow LS upstream of the heater 8th is dependent. So now is the temperature T2 of the air flow LS upstream of the heater 8th measured, it can be detected with greater certainty whether a certain temperature such. B. T1, downstream of the air inlet surface of the heater 8th is measured, to an excessive temperature in the heating 8th indicates or not. Due to the formation of the difference D from the first measurement signal M1 and the second measurement signal M2, a consideration of both temperatures, namely the upstream temperature T2 and the downstream temperature T1 or T3 ensured.

The inventive improvement of the detection of imminent overheating can be dispensed with the use of a fuse in many cases, what the dishwasher 1 simplified. In addition, so the maintenance intensity can be reduced because so no fault must be replaced after a fault. In addition, in the dishwasher according to the invention 1 the life of the heater 8th and to the heater 8th adjoining components, for example the sorption device 21 , the dishwasher 1 be extended because due to the better error detection, the thermal load of the heater 8th or the adjacent components 21 is reduced in case of an error. The latter is based on the fact that, when the difference D is evaluated, a fault can already be concluded with a smaller deviation from the normal value than is the case with exclusive consideration of the first measuring signal M1, without the risk of false detection being increased.

According to an expedient development of the invention, but also as an independent aspect of the invention in a dishwasher described above 1 , is a speed of the fan 7 by the control device 14 influenced as a function of the difference D. As a result, a relatively complex influencing of the comparatively higher power of the heater 8th be supplemented or replaced. In particular, the temperature T1 or T3 of the air flow can thus be downstream of the air inlet surface of the heater 8th be influenced in such a way that under given boundary conditions, such as given a supply voltage, a time-efficient and gentle material heating of the wash liquor S can be done.

In the exemplary embodiment, an increase in the rotational speed relative to a standard rotational speed is provided, provided that an upper limit value OG provided for the difference D is exceeded. As a result, the temperature T1 or T3 of the air flow LS in the region of the heater 8th as well as the inside of the rinsing chamber 2 blown air stream LS 'can be lowered in a simple manner to a harmless value, if it is undesirably high, for example, at too high supply voltage. In addition, the temperatures T1 are in the range of heating 8th lowered.

In addition, in the exemplary embodiment, a reduction of the rotational speed with respect to a standard rotational speed is provided, provided that a lower limit UG provided for the difference D has been reached. In this way, for example, when the supply voltage is too low, the temperature T1 or T3 of the air flow LS or LS 'downstream of the air inlet surface of the heater 8th be increased, so that in this case, an effective heating of the wash liquor S is possible because the temperature T3 of the inside of the washing chamber 2 blown air stream LS 'so above the temperature of the rinse S can be maintained.

In the embodiment is a power of the heater 8th by the control device 14 depending on the difference. In this way, overheating of the heater 8th , Can be effectively avoided, in particular due to a low volume flow of the air flow LS, for example, caused by Spülgut impairment of the flow rate. In addition, such overheating of the heater 8th be avoided due to an excessive supply voltage of the heater. This is of particular importance because the supply voltage is generally the voltage of an external power supply SV, for example the voltage of a conventional home network, which may possibly be 10% to 20% above its nominal value. In addition, the supply voltage with its second power goes into the performance of the heater 8th one.

In this case, a shutdown limit AG is provided in the embodiment for the difference, when it is exceeded, switching off the power of the heater 8th by the control device 14 is provided. This can easily threatened overheating of the heating element 9 the heater 8th and / or the sorbent material 22 the sorption device 21 or to the heater 8th adjacent parts or areas of the dishwasher, but also damage to temperature-sensitive items in the washing chamber 2 be avoided.

Conveniently, when switching off the power of the heater 8th an output of an error message via an operator interface 26 , This allows the operator promptly take measures to eliminate any interference. For example, it may be asked to remove items that obstruct the air flow LS, LS 'over charge, remove.

3 shows a diagram illustrating the basic time course of the difference D at different supply voltages of the heater 8th the air heater 6 ,

If the supply voltage corresponds to its nominal value, the result already in the 2 If, on the other hand, the voltage of the supply is below its nominal value, the result is, in principle, a difference D 'with a smaller one Values. Finally, if the voltage of the supply is above its nominal value, this results in principle in a difference D "with higher values.

In the exemplary embodiment, the switch-off threshold value AG is determined by the control device as a function of a voltage measuring device 24 measured voltage of the external power supply SV for heating 8th established. Thus, in the event of a voltage below its rated value, a cut-off limit AG 'is provided, in the case of a voltage corresponding to its nominal value, the cut-off limit AG and, in the event of a voltage above its rated value, a cut-off limit AG''. In this way, the detection of impending overheating and reaction to it can be further improved.

Overall, the invention aims to operate the air heater in a permitted temperature difference range. The difference D between the water temperature (temperature T2 'of the wash liquor S), which corresponds approximately to the temperature T2 of the intake air flow, if the wash liquor S is circulated in the wash chamber, and the air temperature T1 in the region of the heater (or the air temperature T3 downstream of the heater 8th ) is in the embodiment depending on the volume flow (eg, its reduction may be caused by the intervention of the operator, by covering the intake duct (second air line) and / or blow-out (first air line)) of the mains voltage (voltage of the power supply), and / or the fan speed (speed of the fan).

• – Bei zu niedriger Differenz kann eine Reduzierung des Volumenstroms erfolgen (Drehzahl des Lüfters reduzieren).
• – Bei zu hoher Differenz kann zunächst ein Regelbereich vorgesehen sein, wobei eine Erhöhung des Volumenstroms durch Anhebung der Drehzahl des Gebläses bzw. Lüfters vorgesehen ist, um wieder in den erlaubten Bereich zu gelangen.
• – Oberhalb des Regelbereichs kann eine Abschaltschwelle vorgesehen sein, bei deren Überschreitung die Luftheizung ausgeschaltet wird.

If the temperature difference is not within the permitted range, in particular different reactions can take place:

• - If the difference is too low, the volume flow can be reduced (reduce the speed of the fan).
• - If the difference is too high, a control range can initially be provided, with an increase in the volume flow being provided by raising the rotational speed of the blower or fan in order to return to the permitted range.
• - Above the control range, a shutdown threshold can be provided, beyond which the air heater is switched off.

Instead of a differential temperature, a quotient or a normalized differential temperature standardized in particular to the water temperature T2 'or in the case of a circulated rinsing liquor, which is normalized to the air temperature T2 of the intake air flow, can also be determined from the two measurement signals. Also other relations, d. H. Mathematical links between the two measurement signals of the first sensor and the second sensor may possibly be useful for an evaluation of the temperature behavior in the air duct.

• – es ist kein Einsatz eines Temperaturreglers mehr erforderlich;
• – bei einer Sorptionstrocknungsanlage wird die Lebensdauer des Sorptionsmaterials, insbesondere Zeoliths, erhöht;
• – es sind mehr Reaktionsmöglichkeiten auf unsachgemäßen Betrieb gegeben; wenn z. B. der Volumenstrom zu niedrig ist, kann durch eine Erhöhung der Lüfterdrehzahl eine Überhitzung im Luftkanal bzw. in der Luftleitung vermieden werden;
• – ein weiterer Vorteil liegt darin, dass die Heizung im Fehlbetrieb – wie z. B. bei Lüfterausfall, oder bei teilweiser oder vollständiger Abdeckung der Ansaugöffnung und/oder Ausblasöffnung durch Spülgut – mit einer Relativ-, insbesondere Differenzmessung schneller als nur mit einer absoluten Temperaturwertmessung abgeschaltet werden kann.

In particular, there are the following advantages:

• - It is no longer necessary to use a temperature controller;
• - In a Sorptionstrocknungsanlage the life of the sorbent material, in particular zeolite, increased;
• - there are more opportunities to react to improper operation; if z. B. the volume flow is too low, can be avoided by increasing the fan speed overheating in the air duct or in the air line;
• - Another advantage is that the heater in malfunction - such. B. fan failure, or partial or complete coverage of the intake and / or exhaust opening through items to be washed - with a relative, in particular differential measurement faster than only with an absolute temperature value measurement can be switched off.

In the case of the air heater, if necessary, the sorption device may be omitted and, instead, only a wire heater or another heating unit may be provided for heating the air flow generated by the fan. The above explanations and remarks apply analogously.

In summary, the dishwasher according to the invention comprises such. B. 1 a a rinsing chamber such. B. 2 having washing containers such. B. 2 ' , an air heater such. B. 6 , which at least one air duct such. B. LK between an intake such. B. 10 of the washing container such. B. 2 ' and a blowout such. B. 13 of the washing container such. B. 2 ' having, wherein in the air duct such. B. 11 . 12 a blower such. B. 7 for generating an air flow such. B. LS and a heater such. B. 8th for heating the generated air flow such. B. LS are inserted, and a control device such. B. 14 for influencing, in particular control and / or regulation, at least one rinse cycle. A first sensor such. B. 17 is in the field of heating such. B. 8th or after heating such. B. 8th in the outlet side air line such. B. 12 the air duct such. B. LK for generating a first measurement signal such. B. M1 provided that there is a first temperature such. B. T1, T3 represents. A second sensor such. B. 19 is in the flow direction of the air flow such. B. LS considered before the heater such. B. 8th for generating a second measurement signal such. B. M2 arranged, the temperature such. B. T2 of the sucked from the rinsing chamber of the rinsing tank air flow such. B. LS represents. Conveniently, the second Sensor formed by a temperature sensor in the liquid circuit of the dishwasher, with which the temperature of a wash liquor can be determined, which is used for a liquid-carrying Teilspülgang the respective wash cycle in the washing chamber, in particular by means of one or more spray systems is sprayed. In particular, when circulating rinse liquor by means of a circulation pump, preferably spraying rinse liquor by means of one or more spray systems, the heat stored in their heat energy is transferred from the rinse liquor to the air in the rinsing chamber, so that finally the temperature of the air in the rinsing chamber and thus the temperature T2 the intake air approximately the temperature T2 'corresponds to the wash liquor. The measured by the liquid temperature sensor temperature T2 'of the wash liquor thus represents the temperature such. B. T2 of the sucked air flow such. B. LS in the second, suction-side air line such. B. 11 in front of the heater such. B. 8th ,

In the case of this dishwashing machine according to the invention, it is possible to monitor better by evaluating the two measuring signals as to whether perfect operation of the air heating device is present or not. In particular, it is possible to check whether the temperatures in the air duct and / or the volume flow through the air duct are within permissible limits. For this purpose, the control device determines from the first and the second measurement signal such. B. M1, M2 expediently a relation or relationship, in particular their difference such. B. D, as evaluation signal. The control device such. B. 14 pulls this evaluation signal to control the air heater such. B. 6 approach. Since the heat output of the heater and the air volume flow through the air heater affect in particular the determined relation, preferably difference, of the two measuring signals, these influencing variables can be monitored in an advantageous manner. In this case, the thermal energy transfer between the rinsing liquor and the sucked-in air flow can be taken into account when determining the permissible limits for the determined relation, in particular the difference of the two measuring signals within which proper operation of the air heating device is possible. On the other hand, if only the temperature value brought about by the heating at the end of its heating zone would be measured by means of a temperature sensor, ie only an absolute value measurement of the heating temperature of the heating would be carried out, then the upper temperature limit value at which the heating is switched off would be (shutdown limit temperature), for example greater than the highest occurring during normal operation of the air heater temperature (maximum operating temperature) are selected to prevent false shutdowns of the heater. Would the air that is sucked through the suction port of the washing in the air duct of the air heater, but z. B. be cooled by sprayed in the rinsing chamber water, such. As the pre-wash cycle or intermediate rinse, so this Abschaltgrenztemperatur would be reached or exceeded by the temperature of the air flow flowing through the heater too late or not at all, although the air flow through the air duct is smaller than a target volume flow, which occurs, for example, when the intake and / or outlet opening of the washing container is partially covered by dishes in the washing chamber.

By contrast, in the dishwasher according to the invention with the aid of the second sensor, the influence on the temperature of the washing chamber flowing through the washing chamber and thus of the air flow sucked through the suction opening into the air duct can be taken into account when determining the switch-off limit temperature for the heating. This can now be set lower than the shutdown limit temperature for a sole absolute temperature measurement. It can thus be compared to the desired volume flow reduced air flow, the z. B. by harnesses that covers the intake and / or exhaust or partially in the interior of the washing, are detected earlier and thus improved and appropriate remedy against overheating of the air heater can be initiated by the controller. Thus, from the control device such. B. 14 over the control line such. B. 15 to the blower such. B. 7 a control signal is transmitted, which increases the speed of the fan to increase the air flow through the air duct accordingly.

In an analogous manner to the switch-off threshold temperature, the upper limit temperature for the regular operation of the heater with respect to the upper limit temperature in the case of a sole absolute temperature measurement can also be lowered in the dishwasher according to the invention.

Furthermore, by means of the temperature measurements of the two sensors, the lower temperature limit for the permissible temperature operating range of the air heater can also be adapted more precisely to the actual conditions of the air circulation path between the rinsing chamber and the air heater. For now, by determining the invention a relation, in particular difference, between the measured temperature for the intake air flow and the temperature measured for the air leaving the heater and thus blown out the influence of the thermal energy transfer between the sprayed in the rinsing chamber rinse solution on the air flowing through the rinsing chamber , If, for example, the temperature measured for the air flow in the air duct during or after the action of the heater is higher than the lower temperature limit in the case of the sole absolute temperature measurement, the air heater would continue to operate unchanged in the case of the sole absolute temperature measurement. In the dishwasher according to the invention, however, is additionally detected by means of the second sensor, which has influence in the washing compartment sprayed rinsing water to the temperature of the sucked into the air duct air flow. If, for example, a temperature decrease of the intake air stream is caused by the rinsing liquor, the measured signals of the first and second sensors could now prove that the difference temperature lies below a permissible lower temperature limit due to the determined relation, in particular difference formation. Then the control device would be over the control line 15 to the blower 7 In particular, transmit a control signal to reduce the fan speed to ensure by reducing the air flow a longer exposure time of the heater to the air flowing through the heater and thus a higher thermal energy transfer to this.

Claims (16)

Dishwasher, in particular domestic dishwasher ( 1 ), with a control device ( 14 ) for influencing, in particular control and / or regulation, of a rinse cycle for cleaning items to be washed by means of a rinsing liquor (S), with a rinsing chamber ( 2 ) for receiving the items to be washed during the wash cycle, with an air heater ( 6 ), in particular for heating the rinsing liquor (S) and / or drying the items to be washed by means of an air flow (LS), which a blower ( 7 ) for generating the air flow (LS) and a heater ( 8th ) for heating the air flow (LS), with a first sensor ( 17 ) for generating one with a temperature (T3) of the air flow (LS) downstream of the heater ( 8th ) correlating first measurement signal (M1), and with a second sensor ( 19 ) for generating one with a temperature (T2) of the air flow (LS) upstream of the heater ( 8th ) correlating second measurement signal (M2), wherein the control device ( 14 ) for forming a relation, in particular difference (D), from the first measuring signal (M1) and the second measuring signal (M2) and for influencing the air heating device ( 6 ) is formed on the basis of the relation, in particular difference (D), wherein the second sensor ( 19 ) is arranged, in particular in the liquid circuit of the dishwasher, that the second measurement signal (M2) of the temperature (T2 ') of the rinsing liquor (S) corresponds. Dishwasher according to the preceding claim, characterized in that the air flow (LS) in a closed circuit from the rinsing chamber ( 2 ) over the heater ( 8th ) back to the rinsing chamber ( 2 ) is guided. Dishwasher according to one of the preceding claims, characterized in that the first sensor ( 17 ) in the area of heating ( 8th ), in particular according to the air inlet surface of the heater ( 8th ) and before the end portion thereof, so that the first measurement signal (M1) of a mixing temperature (T1) of the temperature (T2) of the air flow (LS) upstream of the heater ( 8th ) and the temperature (T3) of the air flow (LS) downstream of the heater ( 8th ) corresponds. Dishwasher according to one of claims 1 or 2, characterized in that the first sensor ( 17 ) on a first air line ( 12 ) for directing the air flow (LS) from the heater ( 8th ) to the rinsing chamber ( 2 ), so that the first measurement signal (M1) corresponds to the temperature (T3) of the air flow (LS ') in the first air line. Dishwasher according to one of the preceding claims, characterized in that the second sensor ( 19 ) at one of the rinsing chamber ( 2 ) associated pump pot ( 3 ) is arranged. Dishwasher according to one of the preceding claims, characterized in that the second sensor ( 19 ) on a circulation pump ( 4 ) for circulating the rinsing liquid or at one of the circulating pump ( 4 ) is arranged separate liquid heater. Dishwasher according to one of the preceding claims, characterized in that the control device ( 14 ) is designed such that a power of the heating ( 8th ) by the control device ( 14 ) in dependence on the relation, in particular difference (D), can be influenced. Dishwasher according to one of the preceding claims, characterized in that for the relation, in particular difference (D), a Abschaltgrenzwert (AG) is provided, when exceeding a shutdown of the power of the heating ( 8th ) by the control device ( 14 ) is provided. Dishwasher according to the preceding claim, characterized in that the switch-off threshold value (AG) by the control device ( 14 ) as a function of a voltage measuring device ( 24 ) measured voltage of an external power supply (SV) for the heating ( 8th ). Dishwasher according to claim 8 or 9, characterized in that when switching off the power of the heater ( 8th ) an output of an error message via an operator interface ( 26 ) he follows. Dishwasher according to one of the preceding claims, characterized in that the control device ( 14 ) is designed such that a speed of the blower ( 7 ) by the control device ( 14 ) is influenced as a function of the relation, in particular difference (D). Dishwasher according to the preceding claim, characterized in that an increase in the speed is provided with respect to a standard speed, provided that for the relation, in particular difference (D), provided upper limit (OG) is exceeded. Dishwasher according to claim 11 or 12, characterized in that a reduction of the rotational speed with respect to a standard speed is provided, provided that for the relation, in particular difference (D), provided lower limit value (UG) is exceeded. Dishwasher according to one of the preceding claims, characterized in that the air heating device ( 6 ) a sorption device ( 21 ) with a reversibly dehydratable material ( 22 ), which with switched off heating ( 8th ) for absorbing moisture from the airflow (LS) and when the heating is switched on ( 8th ) is designed to deliver moisture to the airflow (LS). Dishwasher ( 1 ) with a rinsing chamber ( 2 ) having washing containers ( 2 ' ), with an air heater ( 6 ), which at least one air channel (LK) between a suction port ( 10 ) of the washing container ( 2 ' ) and a blow-out opening ( 13 ) of the washing container ( 2 ' ), wherein in the air duct ( 11 . 12 ) a blower ( 7 ) for generating an air flow (LS) and a heating ( 8th ) are inserted for heating the generated air flow (LS), and with a control device ( 14 ) for influencing, in particular controlling and / or regulating, at least one wash cycle, in particular according to at least one of the preceding claims, characterized in that a first sensor ( 17 ) in the area of heating ( 8th ) or after heating ( 8th ) in a bleed-side air line ( 12 ) of the air channel (LK) for generating a first measurement signal (M1) is provided which represents a first temperature present there (T1, T3), and that a second sensor ( 19 ) in the flow direction of the air flow (LS) viewed in front of the heater ( 8th ) is arranged for generating a second measuring signal (M2), the temperature (T2) of the from the rinsing chamber ( 2 ) of the washing container ( 2 ' ) intake air flow (LS), wherein the second sensor ( 19 ) is formed by a temperature sensor in the liquid circuit of the dishwasher, with which the temperature of a rinsing liquor (S) can be determined. Method for operating a dishwasher ( 1 ), in particular a dishwasher ( 1 ) according to one of the preceding claims, in which by means of a control device ( 14 ) a rinse cycle for cleaning items to be washed by means of a rinsing liquor (S) is influenced, in particular controlled and / or regulated, in which the items to be washed in a rinsing chamber ( 2 ) is taken during the rinse, in which an air flow (LS) by means of an air heater ( 6 ) is heated, in particular in which the rinsing liquor (S) by means of an air flow (LS) of an air heater ( 6 ) and / or items to be dried by means of an air flow (LS) of an air heater ( 6 ), wherein the air flow (LS) by means of a blower ( 7 ) and by means of a heater ( 8th ) is heated, in which by means of a first sensor ( 17 ) with a temperature (T3) of the air flow (LS) downstream of the heater ( 8th ) correlating first measurement signal (M1) is generated, and in which by means of a second sensor ( 19 ) with a temperature (T2) of the air flow (LS) upstream of the heater ( 8th ), wherein the second measuring signal (M2) corresponds to the temperature (T2 ') of the washing liquor (S), and wherein the control device (M2) 14 ) a relation, in particular difference (D), from the first measurement signal (M1) and the second measurement signal (M2) formed and the air heater ( 6 ) is influenced by the relation, in particular difference (D).

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