WO2020099017A1

WO2020099017A1 - A laundry dryer comprising an infrared sensor

Info

Publication number: WO2020099017A1
Application number: PCT/EP2019/076421
Authority: WO
Inventors: Murat Kantas; Ihsan Ozan YILDIRIM; Sinan KAYA
Original assignee: Arcelik Anonim Sirketi
Priority date: 2018-11-13
Filing date: 2019-09-30
Publication date: 2020-05-22
Also published as: EP3880879A1; EP3880879B1

Abstract

The present invention relates to a laundry dryer (1) comprising a drum (2) wherein the laundry is loaded; at least one baffle (3) which is mounted onto the inner surface of the drum (2) and which provides the tumbling of the laundry; a control unit (4) which regulates the drying processes; and a temperature measurement unit (7) which is mounted onto the baffle (3) and which has an infrared sensor (6) detecting the temperature of the laundry, by means of the infrared rays radiated from the laundry.

Description

A LAUNDRY DRYER COMPRISING AN INFRARED SENSOR

The present invention relates to a laundry dryer wherein the drying status of the laundry is controlled by measuring the temperature thereof.

In laundry dryers, the drying process is controlled by measuring conductivity during the drying process. The conductivity sensor is composed of two electrodes which are arranged on the front section of the drum. During the drying process, when the laundry in the drum contacts said electrodes, the conductivity of the fabric can be measured. The conductivity is higher when the fabric is wet. As the fabric dries and the moisture therein is reduced, the conductivity thereof decreases. During the drying process, the conductivity of only the fabric which contacts the electrodes can be measured. When a plurality of laundry items are in the drum, the possibility of the laundry contacting the conductivity sensor decreases. In the laundry dryers wherein the dryness is detected by measuring conductivity, it becomes difficult to make the dryness decision with a few mixed laundry items, and the drying process is terminated with the timer. In this case, the laundry is not completely dried or damaged due to overheating.

In the state of the art, embodiments are known wherein a temperature sensor is used for controlling the drying process. The temperature sensors used in the laundry dryers generally measure the temperature of the "processing air". In the laundry dryer disclosed in the Patent Application No. EP 3315654 (A1), the infrared array sensor used for measuring the temperature inevitably measures the temperature of the inner surfaces of the drum in addition to the laundry. Since the measurement contains the temperature of the drum, an estimated or approximate data can be obtained in relation to the temperature of the laundry, and the actional temperature of the laundry being dried cannot be measured, and the actual dryness degree cannot be detected.

The aim of the present invention is the realization of a laundry dryer wherein the temperature and hence dryness level of the laundry is accurately detected and the drying process is controlled.

The laundry dryer realized in order to attain the aim of the present invention comprises a temperature measurement unit which is detachably mounted into a recess-shaped housing opened in the drum baffle. The temperature measurement unit comprises an infrared sensor therein which detects the temperature of the laundry by means of the infrared rays radiated from the laundry. The temperature measurement unit further comprises a microprocessor which processes the signals received from the infrared sensor to transmit the same to the main control unit, and a wireless communication means such as Wi-Fi, Bluetooth, etc.

In an embodiment of the present invention, a load sensor which detects the contact of the laundry with the drum baffle is provided in the drum baffle. When the load sensor detects the contact of the laundry with the drum baffle, the main control unit measures the temperature by means of the infrared sensor.

In another embodiment of the present invention, a proximity sensor which detects the proximity of the laundry to the drum baffle is provided in the drum baffle. When the proximity sensor detects the proximity of the laundry to the drum baffle, the main control unit measures the temperature by means of the infrared sensor.

The laundry dryer realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

Figure 1 - is the schematic view of the laundry dryer of the present invention.

Figure 2 - is the exploded view of a drum baffle and the temperature measurement unit.

Figure 3 - is the perspective view of the drum baffle and the temperature measurement unit which is placed into the housing.

Figure 4 - is the top view of the drum baffle.

Figure 5 - is the view of the cross-section A-A in Figure 4.

The elements illustrated in the figures are numbered as follows:

Laundry dryer
Drum
Baffle
Control unit
Housing
Infrared sensor
Temperature measurement unit
Microprocessor
Wireless communication means
Protective cover
Load sensor

The laundry dryer (1) comprises a body; a drum (2) wherein the laundry is loaded; at least one baffle (3) which is mounted onto the inner surface of the drum (2) and which provides the tumbling of the laundry; and a control unit (main control card) (4) which regulates the drying processes.

The baffle (3) is produced by bending a thin material for example a sheet or injecting plastic with a thin wall thickness in order to reduce the weight and cost, and the baffle (3) mounted onto the inner surface of the drum (2) has a hollow volume.

The laundry dryer (1) of the present invention comprises a temperature measurement unit (7) which is detachably mounted into a housing (5) extending into the hollow inner volume of the baffle (3), which has an infrared sensor (6) detecting the temperature of the laundry by means of the infrared rays radiated from the laundry, and which detects the temperature of the laundry getting in contact with the baffle (3) or getting close to the baffle (3) during the drying process.

The components of the infrared sensor (6), namely the "lens" focusing the infrared rays and the "thermopile" converting the detected radiation data to the voltage, are known in the state of the art, and the definition of "infrared sensor (6)" covers these components.

The temperature measurement unit (7) further comprises a microprocessor (8) which processes the signals received from the infrared sensor (6) to transmit the same to the control unit (4), and a wireless communication (9) means such as Wi-Fi, Bluetooth, etc.

In an embodiment of the present invention, the laundry dryer (1) comprises a protective cover (10) which is mounted onto a surface of the temperature measurement unit (7) getting in contact with the laundry, which covers the infrared sensor (6) in the temperature measurement unit (7) so as to prevent the laundry and the humid air from damaging the infrared sensor (6), which is produced from an infrared transparent material so as to enable the infrared rays radiated from the laundry to reach the "lens" of the infrared sensor (6).

In an embodiment of the present invention, the laundry dryer (1) comprises a load sensor (11) such as load cell, impact sensor, strain gauge, touch switch, etc., which is disposed in the baffle (3) and which detects the force applied by the laundry onto the outer surface of the baffle (3) and/or the outer surface of the temperature measurement unit (7) when the laundry contacts the baffle (3). Such a sensor of this type which is exemplified above and which detects the force applied by the laundry when the laundry contacts the baffle (3) is shortly defined as the "load sensor (11)".

When the load sensor (11) detects the contact of the laundry with the baffle (3), the control unit (4) activates the temperature measurement unit (7) and measures the temperature by activating the infrared sensor (6). When the load sensor (11) detects the interruption of the contact between the laundry and the baffle (3), the control unit (4) deactivates the temperature measurement unit (7) and the infrared sensor (6) does not measure temperature.

In an embodiment of the present invention, the laundry dryer (1) comprises a proximity sensor (not shown in figures) which is disposed in the baffle (3) and which detects the presence of the laundry in the vicinity of the baffle (3) when the laundry gets close (a few mm - a few cm) to the temperature measurement unit (7).

When the proximity sensor detects the presence of the laundry in the vicinity of the baffle (3), the control unit (4) activates the temperature measurement unit (7) and measures the temperature by activating the infrared sensor (6). When the proximity sensor detects that the laundry moves away from the baffle (3), the control unit (4) deactivates the temperature measurement unit (7) and the infrared sensor (6) does not measure temperature.

The infrared sensor (6), which can make contact-free temperature measurement, the microprocessor (8) and the wireless communication means (9) are provided in the temperature measurement unit (7) mounted into the housing (5) opened in the baffle (3). When the laundry gets in contact with or gets close to the temperature measurement unit (7) in the baffle (3), the load sensor (11) or the proximity sensor detects the laundry on or in the vicinity of the baffle (3), and the temperature is measured by activating the infrared sensor (6). When the laundry moves away from the baffle (3) during the rotation of the drum (2), the load on the load sensor (11) is removed or the laundry moves away from the field of view of the proximity sensor, and the infrared sensor (6) stops temperature measurement. The data received from the infrared sensor (6) is transmitted to the microprocessor (8), and the data processed here via measurements and algorithms is transmitted to the control unit (4) via the wireless communication means (9).

The actional temperature of the laundry can be measured by means of the infrared sensor (6), and the control unit (4) regulates the drying process by following said temperature data. Thus, by measuring temperature only when the laundry is on or in the vicinity of the baffle (3), only the temperature of the fabric is measured. Consequently, the temperature data does not mix with the temperature values of the inner surface of the drum (2) or of the process air, and accurate temperature data is obtained. Moreover, the risk of terminating the drying process when the laundry is still wet or damaging the laundry due to prolonged drying time and overheating is eliminated.

Claims

A laundry dryer (1) comprising a drum (2) wherein the laundry is loaded; at least one baffle (3) which is mounted onto the inner surface of the drum (2) and which provides the tumbling of the laundry; and a control unit (4) which regulates the drying processes,

- characterized by a temperature measurement unit (7) which is detachably mounted into a housing (5) formed on the baffle (3) and extending into the hollow inner volume of the baffle (3), which has an infrared sensor (6) detecting the temperature of the laundry, and which detects the temperature of the laundry getting in contact with the baffle (3) or getting close to the baffle (3).
A laundry dryer (1) as in Claim 1, characterized by the temperature measurement unit (7) comprising a microprocessor (8) which processes the signals received from the infrared sensor (6) to transmit the same to the control unit (4), and a wireless communication (9) means.
A laundry dryer (1) as in Claim 1 or 2, characterized by a protective cover (10) which is mounted onto a surface of the temperature measurement unit (7), which covers the infrared sensor (6) in the temperature measurement unit (7), and which is produced from an infrared transparent material.
A laundry dryer (1) as in Claim 1 or 2, characterized by a load sensor (11) which is disposed in the baffle (3) and which detects the contact of the laundry with the baffle (3).
A laundry dryer (1) as in Claim 4, characterized by the control unit (4) which measures the temperature by activating the infrared sensor (6) when the load sensor (11) detects the contact of the laundry with the baffle (3).
A laundry dryer (1) as in Claim 1 or 2, characterized by a proximity sensor which is disposed in the baffle (3) and which detects the presence of the laundry in the vicinity of the baffle (3).
A laundry dryer (1) as in Claim 6, characterized by the control unit (4) which measures the temperature by activating the infrared sensor (6) when the proximity sensor detects the presence of the laundry in the vicinity of the baffle (3).