EP3346050A1 - Laundry treatment device and method for operating same - Google Patents

Abstract

The invention relates to a laundry treatment appliance (1) comprising at least one process air circuit (2) in which a process air can be circulated during a drying process for drying laundry in the process air circuit (2), at least one temperature sensor (6) arranged on the process air circuit (2) ) for detecting a temperature of the process air, at least one humidity sensor (7) arranged on the process air circuit (2) for detecting a relative humidity of the process air and at least one electronic unit (8) connected to the temperature sensor (6) and the humidity sensor (7). In order to provide a laundry treating appliance (1) capable of more accurate detection of the moisture content of laundry to be dried for the purpose of improving a drying process carried out with the laundry treating appliance (1), it is proposed that the electronic unit (8) be set up during the drying process the measured temperature and the measured relative humidity to determine a water loading of the process air, to determine a maximum of the water loading of the process air, to determine a value of a deviation of the current water load from the maximum of the water load and to generate a shutdown signal to terminate the drying process, if the Value of the deviation reaches a predetermined limit.

Description

The invention relates to a laundry treatment appliance, in particular a tumble dryer or a laundry dryer, having at least one process air circulation in which a process air can be circulated during a drying process for drying laundry located in the process air cycle, at least one temperature sensor arranged at the process air circuit for detecting a temperature of the process air, at least one arranged on the process air circuit humidity sensor for detecting a relative humidity of the process air and at least one connected to the temperature sensor and the humidity sensor electronic unit.

The invention further relates to a method for operating a laundry treatment appliance, which has at least one process air cycle in which a process air can be circulated during a drying process for drying laundry present in the process air cycle, wherein a temperature and a relative humidity of the process air are measured during the drying process become.

A tumble dryer comprises a process air cycle in which a process air is circulated during the execution of a drying process. The process air is in this case passed through a container in which a laundry drum containing laundry to be dried is rotatably arranged and which forms a portion of the process air cycle.

A degree of moisture or degree of drying of laundry to be dried inside the laundry drum can be determined conventionally, for example, by measuring the electrical resistance of the laundry. Alternatively, a moisture level or degree of dryness of laundry to be dried within the laundry drum can be conventionally determined, for example, by means of a measurement of the relative humidity of the process air by means of a moisture sensor.

DE 10 2006 053 274 A1 discloses a method for determining the amount of charge of laundry in a cargo space with air outlet of a tumble dryer, in particular an exhaust air dryer, wherein the absolute humidity in the air outlet from the hold is measured and the amount of charge in the hold by determining the maximum value and / or the course of the absolute humidity is determined in the air outlet from the hold.

The above-described conventional methods depend on the measurement accuracy and durability of the respective sensors used. It is known in this context that moisture sensors, especially in areas of high relative humidity have large measurement errors or measurement inaccuracies.

An object of the invention is to provide a laundry treatment appliance, with which a more accurate detection of the degree of moisture to be dried laundry is possible to improve a feasible with the laundry treatment device drying process.

This object is solved by the independent claims. Advantageous embodiments are given in the following description, the dependent claims and the figure, these embodiments each taken alone or in various combinations of at least two of these embodiments can represent each other a further developing, especially preferred or advantageous, aspect of the invention. Embodiments of the laundry treatment appliance can correspond to embodiments of the method, and vice versa, even if not explicitly indicated in the following case in individual cases.

A laundry treatment device according to the invention, in particular a tumble dryer or a laundry dryer, comprises at least one process air cycle in which a process air can be circulated during a drying process for drying laundry located in the process air cycle, at least one temperature sensor arranged on the process air circuit for detecting a temperature of the process air, at least one at the Process air circulation arranged humidity sensor for detecting a relative humidity of the process air and at least one connected to the temperature sensor and the humidity sensor electronic unit. The electronics unit is set up, determine during the drying process from the measured temperature and the measured relative humidity, a water loading of the process air to determine a maximum of the water loading of the process air to determine a value of a deviation of the current water load of the maximum of the water load and a shutdown signal to terminate the drying process generate when the value of the deviation reaches a predetermined limit.

According to the invention, the drying process is not controlled and / or regulated as a function of the absolute humidity of the process air, as a function of a deviation of the instantaneous water loading of the process air from the determined maximum of the water loading of the process air. As a result, the control and / or regulation of the drying process is independent of the measurement accuracy and a drift of measured values of the moisture sensor over the life of the moisture sensor. In particular, this makes it possible to conclude the degree of dryness of the laundry to be dried independently of the measuring accuracy of the moisture sensor.

After one of the respective loading of the laundry drum and the respective initial moisture of the laundry to be dried dependent heating phase of the drying process, the drying of the laundry in a stationary state. In this case, the relative humidity of the effluent from the laundry drum of the laundry treatment appliance process air can rise to 100%. Both the water loading of the process air to be introduced into the container and the water loading of the process air flowing out of the container have a maximum. Such a maximum of the water loading of the process air is continuously determined according to the invention during the drying process. As the drying level of the laundry increases, the water load of the process air decreases.

wobei m_W für die Wassermasse, m_L für die Masse der trockenen Luft, M_W für die Molmasse des Wassers, M_L für die Molmasse der trockenen Luft, p_s für den Dampfdruck, p für den Gesamtdruck und T für die Temperatur steht. Der Gesamtdruck p kann bei der vorliegenden Erfindung als konstant angenommen werden und entspricht dem Luftdruck in der Umgebung des Wäschebehandlungsgeräts. Der Dampfdruck p_s(T) kann aus der Temperaturmessung ermittelt werden. Folglich kann die Wasserbeladung der Prozessluft erfindungsgemäß aus der Temperaturmessung und der Messung der relativen Feuchtigkeit berechnet werden.The water loading x of air is related to the relative humidity φ as follows: $$x=\frac{m_W}{m_L}=\frac{M_W}{M_L}\cdot \frac{p_S\left(T\right)}{p/\phi -p_S\left(T\right)}=0.622\cdot \frac{p_S\left(T\right)}{p/\phi -p_S\left(T\right)}$$

where m _{W is} the mass of water, m _{L is} the mass of the dry air, M _{W is} the molecular weight of the water, M _{L is} the molar mass of the dry air, p _{s is} the vapor pressure, p is the total pressure and T is the temperature. The total pressure p can be assumed to be constant in the present invention and corresponds to the air pressure in the vicinity of the laundry treatment appliance. The vapor pressure p _s (T) can be determined from the temperature measurement. Consequently, according to the invention, the water loading of the process air can be calculated from the temperature measurement and the relative humidity measurement.

The electronic unit may be formed by a device electronics of the laundry treatment appliance or formed as a separate unit. In the former case, the invention can be realized inexpensively by a software implementation in the device electronics, when the laundry treatment device additionally has the temperature sensor and the humidity sensor. As a result, retrofitting existing laundry treatment equipment with the functionality of the invention is possible. If the electronics unit is formed by the device electronics of the laundry treatment appliance, the electronic unit can use the generated shutdown signal itself to end the drying process when the value of the deviation reaches the predetermined limit.

The process air cycle comprises at least one process air blower with which the process air in the process air cycle can be recirculated during a drying process. In addition, the process air circuit may have at least one process air filter for purifying the process air. The fact that the temperature sensor is arranged on the process air circuit means that it is arranged at least partially within the process air circuit in order to come into direct contact with the process air. The fact that the moisture sensor is arranged on the process air circuit means that it is at least partially disposed within the process air circuit in order to come into direct contact with the process air.

The laundry treatment appliance can also have at least one heating device for heating the process air, which is arranged on the process air circuit. The heater may be formed, for example, as an electrical resistance heater or formed by a heat exchanger of a heat pump. Furthermore, this includes Laundry treatment device at least one arranged on the process air circuit condensation device for condensing moisture contained in the process air. The condensation device may be formed by a heat exchanger of a heat pump or as a separate unit.

The laundry treatment device according to the invention may also have two or more temperature sensors for detecting the temperature of the process air and / or two or more humidity sensors for detecting the relative humidity of the process air.

The laundry treatment appliance can be designed as a tumble dryer, washer-dryer or cabinet dryer.

According to an advantageous embodiment, the moisture sensor is arranged with respect to a flow direction of the process air in the process air circuit in front of a container of the laundry treatment appliance, which accommodates a laundry drum of the laundry treatment appliance and forms a portion of the process air cycle, and after a arranged on the process air circuit condensation device of the laundry treatment appliance. Since the relative humidity of the process air after passing through the condenser is significantly lower than that of the effluent from the container process air, the humidity sensor is exposed to a lower relative humidity. This prevents the moisture sensor from being affected by high relative humidity, which would make measuring the relative humidity inaccurate. In particular, when using multiple humidity sensors, this positioning of the moisture sensors is advantageous, since both the temperature, and the relative humidity of the process air in the said region of the process air circuit are subject to lower fluctuations. If several moisture sensors with respect to the flow direction of the process air in the process air circuit to the container and before the condensation device arranged, the measured values of the individual moisture sensors could differ so much from each other at a maximum water loading of the process air and a water loading of the process air towards the end of the drying process, that a precise control and / or regulation of the drying process would no longer be possible. The In addition, the present embodiment eliminates the need for elaborate readout of the humidity sensors according to quality classes.

According to a method according to the invention for operating a laundry treatment appliance which has at least one process air cycle in which a process air is circulated during a drying process for drying laundry present in the process air cycle, a temperature and a relative humidity of the process air are measured during the drying process Drying process from the measured temperature and the measured relative humidity determines a water loading of the process air, a maximum of the water loading of the process air is determined, a value of a deviation of the current water load from the maximum of the water load is determined and the drying process is terminated when the value of the deviation reached a predetermined limit.

With the method, the advantages mentioned above with respect to the laundry treatment appliance are connected accordingly. In particular, the laundry treatment appliance according to one of the aforementioned embodiments or any combination of at least two of these embodiments can be used to carry out the process.

According to an advantageous embodiment, the relative humidity of the process air is measured with respect to a flow direction of the process air in the process air circuit in front of a container of the laundry treatment appliance, which receives a laundry drum of the laundry treatment appliance and forms a portion of the process air cycle, and after a arranged on the process air circuit condensation device of the laundry treatment appliance. With this embodiment, the advantages mentioned above with respect to the corresponding embodiment of the laundry treatment device are connected accordingly.

The invention is not limited to the specified combination of the features of the independent claims and the dependent claims. In addition, there are further possibilities, individual features, in particular if they arise from the patent claims, the following description of the embodiment or directly from the figure revealed to combine with each other. In addition, the reference of the claims to the figure by the use of reference numerals is not intended to limit the scope of the claims to the illustrated embodiment.

Fig. 1

eine schematische Darstellung eines Ausführungsbeispiels für ein Wäschebehandlungsgerät.

In the following, the invention will be explained by way of example with reference to the attached figure with reference to a preferred embodiment. It shows:

Fig. 1

a schematic representation of an embodiment of a laundry treatment device.

Fig. 1 shows a schematic representation of an embodiment of a laundry treatment device. 1

The laundry treatment appliance 1 comprises a process air circuit 2, in which a process air corresponding to the flow direction 3 can be circulated during a drying process for drying laundry located in the process air circuit 2. Furthermore, the laundry treatment device 1 comprises a container 4, which receives a laundry drum 5 of the laundry treatment appliance 1 and forms a portion of the process air circuit 2.

In addition, the laundry treatment device 1 comprises a arranged on the process air circuit 2 temperature sensor 6 for detecting a temperature of the process air. Furthermore, the laundry treatment device 1 comprises a moisture sensor 7 arranged on the process air circuit 2 for detecting a relative humidity of the process air. Furthermore, the laundry treatment appliance 1 comprises an electronic unit 8 connected to the temperature sensor 6 and the moisture sensor 7.

The electronic unit 8 is set up to determine a water loading of the process air during the drying process from the measured temperature and the measured relative humidity, to determine a maximum of the water loading of the process air, to determine a value of a deviation of the instantaneous water load from the maximum of the water load and Shutdown signal to terminate the drying process when the value of the deviation reaches a predetermined limit.

With regard to the flow direction 3 of the process air, the moisture sensor 7 and the temperature sensor 6 are arranged in the process air circuit 2 in front of the container 4 and downstream of a condensation device 9 of the laundry treatment device 1 arranged on the process air circuit 2.

LIST OF REFERENCE NUMBERS

1

Laundry treatment device

2

Process air circuit

3

Flow direction (process air)

4

container

5

washing drum

6

temperature sensor

7

humidity sensor

8th

electronics unit

9

condensation device

Claims (4)

Laundry treatment device (1), in particular tumble dryer or washer-dryer, comprising at least one process air cycle during a drying process for drying laundry located in the process air circuit (2), at least one temperature sensor arranged at the process air circuit (2) ( 6) for detecting a temperature of the process air, at least one humidity sensor (7) arranged on the process air circuit (2) for detecting a relative humidity of the process air and at least one electronic unit (8) connected to the temperature sensor (6) and the humidity sensor (7), characterized in that the electronic unit (8) is adapted to determine a water loading of the process air during the drying process from the measured temperature and the measured relative humidity, to determine a maximum of the water loading of the process air, a value of a deviation of the moment to determine water load from the maximum of the water load and to generate a shutdown signal to terminate the drying process when the value of the deviation reaches a predetermined limit. A laundry treatment appliance (1) according to claim 1, characterized in that the moisture sensor (7) with respect to a flow direction (3) of the process air in the process air circuit (2) in front of a container (4) of the laundry treatment appliance (1) comprising a laundry drum (5) of the Laundry treatment device (1) receives and forms a portion of the process air circuit (2), and according to a to the process air circuit (2) arranged condensation device (9) of the laundry treatment device (1) is arranged. Method for operating a laundry treatment appliance (1) which has at least one process air circuit (2) in which a process air can be circulated during a drying process for drying laundry located in the process air circuit (2), wherein a temperature and a relative humidity of the Process air to be measured during the drying process, characterized in that during the drying process from the measured temperature and the measured relative humidity, a water loading of the process air is determined that a maximum of the water loading of the process air is determined that a value of a deviation of the instantaneous water load of the Maximum of the water load is determined and that the drying process is terminated when the value of the deviation reaches a predetermined limit. A method according to claim 1, characterized in that the relative humidity of the process air with respect to a flow direction (3) of the process air in the process air circuit (2) in front of a container (4) of the laundry treatment appliance (1), the laundry drum (5) of the laundry treatment appliance (1 ) and forms a section of the process air circuit (2), and is measured according to a condensation device (9) of the laundry treatment appliance (1) arranged on the process air circuit (2).

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