Laundry dryer and method of laundry drying

Abstract

The present invention relates to a laundry dryer, which is configured to identify the humidity inside the laundry dryer with at least one humidity and / or temperature sensor, and to the method of laundry drying. The humidity and temperature sensor (12) measures the humidity and temperature of the drying air inside the laundry dryer (1), after which the two measured parameters are compared to the final values stored in the storage of the laundry dryer (1). Laundry drying is completed once the measured parameters match the final values.

Description

LAUNDRY DRYER AND METHOD OF LAUNDRY DRYING

[0001] The present invention relates to a laundry dryer, which is configured to identify the humidity inside the laundry dryer with at least one humidity and / or temperature sensor, and to the method of laundry drying.

[0002] The laundry dryer referred to above is disclosed in document US 2023250571 Al and comprises at least one sensor for sensing the internal humidity of the laundry dryer, a storage for storing at least one instruction, and a processor connected to the storage and configured to operate the laundry dryer. The said processor is configured to obtain, based on following at least one instruction, the internal humidity of the laundry dryer by means of at least one sensor, to identify the external humidity of the laundry dryer based on the obtained internal humidity, to obtain, based on the change in internal humidity and the change in external humidity, information about the amount of humidity in an item to be dried, which is inserted inside the laundry dryer, and to determine whether drying has been completed by comparing information about the amount of humidity in an item with a threshold value.

[0003] A shortcoming of the said solution is that it is not possible to accurately dry difficult- to-dry laundry, such as jackets, quilted jackets, ski trousers, pillows, and similar. Moreover, sensor issues arise in the event of network disturbances or abnormal ambient conditions, such as elevated ambient temperatures, increased air humidity, or similar factors.

[0004] The object of the present invention is to create a laundry dryer that will eliminate the shortcomings of the known solution.

[0005] The object according to the present invention is accomplished by the characteristics set forth in the characterising portion of claim 1. Details of the invention are disclosed in the corresponding sub-claims.

[0006] The invention is further described in detail by way of a non-limiting embodiment and with reference to the accompanying drawings whereFig. 1 shows a diagram of a laundry dryer according to the invention, andFig. 2 shows a flowchart of temperature and relative humidity during drying.

[0007] Arranged inside a laundry dryer 1 is a drum 2, inside which the laundry to be dried is inserted and which can be closed by means of a door 3. During drying, a warm and humidified flow A of air is guided through a rectifier 4 of air into a heat pump assembly 5, where it is cooled. From the said assembly 5, condensate flows through a channel 6 and through a pipe 7 into a housing 8 of a pump 9, which pumps the condensate through a duct 10 and into a condensate receptacle 11. The said housing 8 is arranged together with the pump 9 in an area below the said assembly 5, while the said condensate receptacle 11 is arranged in an area above the drum 2 of the laundry dryer 1.

[0008] Arranged directly adjacent to the exit from the drum 2 to the rectifier 4 of air is a sensor 12 of temperature and relative humidity. The said sensor 12 is selected as a resistive sensor and is primarily arranged in the area of maximum air flow from the drum 2, which ensures reliable parameter measurements.

[0009] The dry and hot flow B of air that enters the drum 2 of the laundry dryer 1 is humidified while passing through the drum 2 during laundry drying due to the laundry being wet. The flow A of humid air travels from the drum 2 to the rectifier 4 of air, where the sensor 12 is arranged by means of which the Rhvalue of relative humidity and T value of temperature of the flow A of humid air are measured. The said sensor 12 is connected to a power supply unit and control unit, which are components of the laundry dryer 1 and are not the subject of the invention. The said control unit comprises at least one storage, processor, user interface and software that manages the laundry drying process inside the drum 2 of the laundry dryer 1. The said flow A of humid air travels further to the said assembly 5, where the flow A of warm humid air cools down, wherein the moisture condenses and is eliminated from the flow A of humid air. The cooled and dehumidified flow of air is then re-heated and re-enters the drum 2 as a dry, hot flow B of air.

[0010] Fig. 2 shows a time course of Rhvalues of relative humidity measured by means of the sensor 12 as well as T values of temperature of the drying air used during laundry drying,which is measured inside the drum 2. During laundry drying inside the drum 2 of the laundry dryer 1, the Rhvalue of relative humidity drops, while the T value of temperature rises. When the Rhvalue of air in the drum 2 used for laundry drying, which is measured by means of the sensor 12, reaches the final Rhk value of relative humidity, the said software of the said control unit initiates a verification of the temperature conditions. Immediately as the minimal temperature difference between the initial Tsvalue of temperature and the current T value of temperature is reached, the said software of the said control unit initiates cooling and the completion of the drying cycle. The said final Rhk value of relative humidity is determined in advance for different types of laundry to be dried and stored in the said storage of the said control unit.

[0011] Relative to the adjustable time parameter after the first turning on of the compressor or heater of the laundry dryer 1, once the thermodynamic conditions in the drum 2 are stabilised, the sensor 12 detects the initial Tsvalue of temperature of the drying air inside the drum 2. The said software of the said control unit obtains from the sensor 12 the initial Tstemperature value of the drying air and stores it in the said storage of the control unit.

[0012] During the entire drying process, the sensor 12 measures in time t, be it continuously or in set time intervals, the current Rhvalue of relative humidity inside the rectifier 4 of air and transmits it to the said control unit. The entire time, the latter compares the said measured Rhvalue of relative humidity to the said final Rhkvalue of relative humidity. When the measured Rhvalue of relative humidity reaches the said final Rhk value of relative humidity, i.e. Rh< Rhk , the first condition for the completion of drying is met.

[0013] Subsequently, the second condition, i.e. the temperature condition, is checked, namely whether the AT value of the current temperature difference in time t between the current T value of temperature and initial Tsvalue of temperature is greater than or equal to the final ATkvalue of temperature difference determined in advance and stored in the said storage of the said control unit. If the second condition (AT > ATk) is also met, the drying can proceed to the cooling phase and finish. If any of the two said conditions is not met, namely Rh> Rhk and / or AT < ATk, both conditions are checked again and the described loop repeats until both conditions are met.

[0014] The described method allows for accurate drying of regular laundry and laundry, such as jackets, quilted jackets, and ski trousers, which normally tends to be more difficult to dry ortakes a longertime to dry than regular laundry.

Claims

Claims1. A method of drying laundry in a laundry dryer, which is configured to identify humidity and / or temperature inside a drum of the laundry dryer by means of at least one humidity and / or temperature sensor, characterised in that it comprises the following steps: a) measuring, when the thermodynamic conditions inside the drum (2) stabilise by means of a sensor (12) for sensing the initial value (Ts) of temperature of the drying air inside the drum (2), and transmitting the said initial value (Ts) of temperature from the sensor (12) to a control unit, where software stores it in a storage of a control unit, b) measuring by means of the sensor (12), during the entire laundry drying cycle, the current value (Rh) of relative humidity of the drying air, c) comparing inside the control unit, during the entire laundry drying cycle, the current values (Rh) of relative humidity of air measured using the sensor (12) by means of the final value (Rhk) of relative humidity that has been determined in advance and stored in the said storage of the said control unit, d) comparing inside the control unit, whenever the said measured value (Rh) of relative humidity of the drying air reaches the said final value (Rhk) of relative humidity, whether the current value (AT) of temperature difference in time (t) between the current value (T) of temperature and the initial value (Ts) of temperature is greater than or equal to the final value (ATk) of temperature difference determined in advance and stored in the said storage of the said control unit, e) entering a drying completion phase if the current value (Rh) of relative humidity is less than or equal to the final value (Rhk) of relative humidity and if the current value (AT) of temperature difference is greater than or equal to the final value (ATk) of temperature difference, f) repeating steps c) through d) if Rh > Rhk and / or AT < ATk, until step e) is completed, i.e. Rh < Rhk and AT > ATk.

2. The method according to claim 1, characterised in that the said simultaneousmeasurement after step b) and comparison after step c) are performed continuously.

3. The method according to claim 1, characterised in that the said simultaneous measurement after step b) and comparison after step c) are performed at a set time interval.

4. The method according to any of the preceding claims, characterised in that the said final value (Rhk) of relative humidity is determined in advance for different types of laundry that is to be dried, and stored in the said storage of the said control unit.

5. The method according to any of the preceding claims, characterised in that the said final value (ATk) of temperature difference is determined in advance for different types of laundry that is to be dried, and stored in the said storage of the said control unit.

6. The laundry dryer, which is configured to identify the humidity and / or temperature inside the drum of the laundry dryer with at least one humidity and / or temperature sensor, wherein, during drying, the warm and humidified flow of air is guided through a rectifier of air into a heat pump assembly, where it is cooled, for performing the method according to any of the preceding claims, characterised in that the sensor (12) of humidity and temperature is arranged directly adjacent to the exit from the drum (2) into the rectifier (4) of air.

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