Patent Description:
It is aimed to eliminate viruses and bacteria on the laundry while the same is treated and dried in laundry dryers. Most of the viruses and bacteria cannot survive at temperatures above <NUM>° C. Additional, UV light sources are used to eliminate viruses and bacteria in the laundry dryers. However, since the economic life of the UV light sources is not very long, said components are not activated during the entire drying process. In state of the art embodiments, generally after the laundry is detected to be dry, the UV light source is activated for a while so as to provide sterilization. Since the UV light sources cannot provide the same rate of radiation at every temperature, an efficient sterilization cannot be performed when the UV light source is operated after the drying process.

In the Patent Application No. <CIT>, a laundry dryer comprising a UV light source is disclosed.

In the Patent Application No <CIT>, a laundry dryer comprising a ultraviolet lamp for disinfecting clothes in a rotatable drum is disclosed, wherein the laundry dryer comprises further an airflow circulation passage which provides the delivery of drying air into the drum, a heat pump with a compressor and a refrigerant cycle, a temperature sensor disposed in the airflow circulation passage to measure the temperature of air drawn from the drum, and a further temperature sensor arranged at the outlet of the condenser of the heat pump.

In the Patent Application No <CIT>, a washing and drying machine comprising an irradiating light source is disclosed.

The aim of the present invention is the realization of a laundry dryer with improved sterilization performance.

The laundry dryer of the present invention is defined in claim <NUM> and comprises a body; a drum which is disposed in the body; an air circulation duct which provides delivery of air into the drum; a compressor which is disposed in the body and which provides a refrigerant cycle; a first temperature sensor which is disposed on the compressor and which measures a temperature of the compressor; a second temperature sensor which is disposed in the air circulation duct and which measures a temperature of the air drawn from the drum; and
a UV light source which is disposed in the body and which emits UV light into the drum. The light source can be UV-A, UV-B or UV-C. In a preferred version of the present invention, the UV light source is a UV-C light source.

The laundry dryer of the present invention further comprises a control unit which is configured to operate the UV light source when a temperature value received from the second temperature sensor is above <NUM><NUM> C and turns off the same when said temperature is above <NUM><NUM> C if a difference between a temperature value received from the first temperature sensor and a temperature value received from the second temperature sensor is above a first threshold value predetermined by the producer and if a temperature value received from the second temperature sensor is above a second threshold value predetermined by the producer after the compressor is operated for a first period of time predetermined by the producer. After the compressor is operated, the temperature values received from the first temperature sensor and the second temperature sensor start to increase. After approximately <NUM>,<NUM> seconds, the compressor reaches the range where the same operates in steady state. For <NUM>,<NUM> seconds, the temperature of the compressor and the temperature of the air drawn from the drum increase. When the ambient temperature is the same room temperature, the difference between the temperature value received from the first temperature sensor and the temperature value received from the second temperature sensor is above the first threshold value Moreover, the temperature value received from the second temperature sensor is above the second threshold value. When the ambient temperature is approximately the same as the room temperature, the temperature received from the second temperature sensor reaches <NUM>° C in approximately <NUM>,<NUM> seconds. If the compressor continues operating, the temperature received from the second temperature sensor reaches <NUM><NUM> C in approximately <NUM>,<NUM> seconds.

In an embodiment of the present invention, the control unit operates the UV light source if a difference between a temperature value received from the first temperature sensor and a temperature value received from the second temperature sensor is below the first threshold value and if a temperature value received from the second temperature sensor is below the second threshold value, and turns off the UV light source when a temperature value received from the second temperature sensor exceeds <NUM><NUM> C. When the ambient temperature is approximately <NUM><NUM> C, the difference between the temperature value received from the first temperature sensor and the temperature value received from the second temperature sensor is below the first threshold value Moreover, the temperature value received from the second temperature sensor is below the second threshold value.

When the ambient temperature is approximately <NUM><NUM> C, the temperature of the drying air in the drum reaches <NUM><NUM> C in a period of time longer than <NUM>,<NUM> seconds. Therefore, when the ambient temperature is detected to be low thanks to the measurements made after the first period of time, the control unit operates the UV light source immediately after the end of the first period of time. Thus, by operating the UV light source for a longer period of time at a low ambient temperature, the viruses and bacteria on the laundry are eliminated.

In an embodiment of the present invention, the laundry dryer comprises a humidity sensor. When a value received from the humidity sensor falls below a predetermined value, the control unit decides that the laundry in the drum is dry, and the drying process is terminated. At the end of the drying process, the control unit turns off the compressor and the UV light source.

In an embodiment of the present invention, the control unit does not operate the UV light source if a temperature value received from the second temperature sensor is below <NUM><NUM> C. The sterilization effect and the radiation power of the UV light source significantly decrease at temperatures under <NUM><NUM> C. Consequently, energy efficiency is provided.

In an embodiment of the present invention, the first threshold value is <NUM><NUM> C. In an embodiment of the present invention, the second threshold value is <NUM><NUM> C.

By means of the present invention, a laundry dryer is realized, wherein the sterilization performance is improved by means of a control unit which operates the UV light source at ranges where the same can be efficiently operated in terms of sterilization.

The advantages of the laundry dryer of the present invention will be disclosed with the detailed description of the embodiments with reference to the accompanying figure, where:
<FIG> - is the schematic view of the laundry dryer in an embodiment of the present invention.

The following numerals are referred to in the description of the present invention:.

The laundry dryer (<NUM>) comprises a body (<NUM>); a drum (<NUM>) which is disposed in the body (<NUM>) and wherein the laundry is loaded; an air circulation duct (<NUM>) which provides the delivery of the drying air into the drum (<NUM>); a compressor (<NUM>) which is disposed in the body (<NUM>) and which provides the refrigerant cycle; a first temperature sensor (<NUM>) which is disposed on the compressor (<NUM>) and which measures the temperature of the compressor (<NUM>); a second temperature sensor (<NUM>) which is disposed in the air circulation duct (<NUM>) and which measures the temperature of the air drawn from the drum (<NUM>); and a UV light source (<NUM>) which is disposed in the body (<NUM>) and which emits UV light into the drum (<NUM>). The second temperature sensor (<NUM>) is positioned in the vicinity of the air outlet of the drum (<NUM>). In the preferred version of the present invention, the second temperature sensor (<NUM>) is disposed behind the filter (not shown in figures) which retains the fibers breaking off from the laundry during the drying process. The UV light source (<NUM>) is positioned on the part, facing the inner volume of the drum (<NUM>), of the front bearing which rotatably supports the drum (<NUM>).

The laundry dryer (<NUM>) comprises a control unit (<NUM>) which operates the UV light source (<NUM>) when the temperature value received from the second temperature sensor (<NUM>) is above <NUM><NUM> C and turns off the same when said temperature is above <NUM><NUM> C if the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) is above a first threshold value predetermined by the producer and if the temperature value received from the second temperature sensor (<NUM>) is above a second threshold value predetermined by the producer after the compressor (<NUM>) is operated for a first period of time predetermined by the producer. The UV light source (<NUM>) provides a higher amount of radiation as the ambient temperature increases. For example, when operated at <NUM><NUM> C, the UV light source (<NUM>) radiates at <NUM> microwatt/cm<NUM> while the same radiates at approximately <NUM> microwatt/cm<NUM> at <NUM><NUM> C. The amount of radiation exceeds <NUM> microwatt/cm<NUM> at temperatures above <NUM>° C, ensuring a higher light intensity. At temperatures above <NUM><NUM> C, most of bacteria and viruses cannot survive due to high heat. Therefore, the UV light source (<NUM>) is not required to be operated at temperatures above <NUM><NUM> C. In the laundry dryers (<NUM>) wherein the ambient temperature is close to the room temperature, the drying air can be delivered into the drum (<NUM>) at a high temperature in a short time. However, in the laundry dryers (<NUM>) wherein the ambient temperature is approximately <NUM><NUM> C, it takes time to heat the drying air to be delivered into the drum (<NUM>) to high temperatures. The ambient temperature is detected by means of the data received from the first temperature sensor (<NUM>) which is provided on the compressor (<NUM>) and which measures the temperature of the body of the compressor (<NUM>), and the second temperature sensor (<NUM>) which measures the temperature of the air drawn from the drum (<NUM>). To this end, first the compressor (<NUM>) is operated for a first period of time. The compressor (<NUM>) is required to be operated for a period of time to reach the efficient operation range. This period of time is approximately between <NUM>,<NUM> seconds and <NUM>,<NUM> seconds in the laundry dryers (<NUM>). In a preferred version of the embodiment, the first period of time is <NUM>,<NUM> seconds. The increase rate of the temperature of the compressor (<NUM>) varies depending on the temperature of the environment where the laundry dryer (<NUM>) is installed. After the compressor (<NUM>) is operated, the temperature of the air delivered into the drum (<NUM>) also increases. As the ambient temperature increases, the increase rate of the temperature of the air drawn from the drum (<NUM>) decreases. For example, in the laundry dryer (<NUM>) operated at an ambient temperature of <NUM>° C, the value received from the second temperature sensor (<NUM>) is <NUM><NUM> C at the mark of <NUM>,<NUM> seconds while in the laundry dryer (<NUM>) operated at an ambient temperature of <NUM><NUM> C, the value received from the second temperature sensor (<NUM>) is <NUM><NUM> C at the mark of <NUM>,<NUM> seconds. It is determined that the ambient temperature is almost the same as the room temperature (<NUM><NUM> C) if the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) is above a first threshold value predetermined by the producer and if the temperature value received from the second temperature sensor (<NUM>) is above a second threshold value predetermined by the producer. In the laundry dryer (<NUM>) operated under conditions where the ambient temperature is almost the same as the room temperature, the temperature of the air delivered into the drum (<NUM>) can be increased in a short time. In this case, the UV light source (<NUM>) is operated at temperatures between <NUM>° C and <NUM><NUM> C where the efficiency thereof is high, the laundry loaded into the drum (<NUM>) is enabled to be sterilized. When the value received from the second temperature sensor (<NUM>) exceeds <NUM><NUM> C, the control unit (<NUM>) operates the UV light source (<NUM>). When the value received from the second temperature sensor (<NUM>) falls below <NUM><NUM> C or exceeds <NUM><NUM> C, the control unit (<NUM>) turns off the UV light source (<NUM>).

In another embodiment of the present invention, the laundry dryer (<NUM>) comprises the control unit (<NUM>) which operates the UV light source (<NUM>) if the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) is below the first threshold value and if the temperature value received from the second temperature sensor (<NUM>) is below the second threshold value, and which turns off the UV light source (<NUM>) when the temperature value received from the second temperature sensor (<NUM>) exceeds <NUM><NUM> C. When the laundry dryer (<NUM>) is operated at a low ambient temperature, the increase rate of the temperature of the compressor (<NUM>) decreases a little while the increase rate of the temperature of the air drawn from the drum (<NUM>) increases. In this case, after the compressor (<NUM>) is operated for approximately <NUM>,<NUM> seconds, the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) is below the first threshold value.

Moreover, in the low ambient temperature, after the first period of time elapses upon the operation of the compressor (<NUM>), the value received from the second temperature sensor (<NUM>) is below the second threshold value predetermined by the producer. Since the temperature of the air drawn from the drum (<NUM>) reaches <NUM><NUM> C in a long time when the laundry dryer (<NUM>) is operated at low ambient temperature, the control unit (<NUM>) immediately operates the UV light source (<NUM>) if, at the end of the first period of time, the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) is below the first threshold value and if the temperature value received from the second temperature sensor (<NUM>) is below the second threshold value. When the temperature value received from the second temperature sensor (<NUM>) exceeds <NUM><NUM> C, the control unit (<NUM>) turns off the UV light source (<NUM>). In a version of the present invention, if the temperature value received from the second temperature sensor (<NUM>) never exceeds <NUM><NUM> C during the program selected via the control panel, the control unit (<NUM>) turns off the UV light source (<NUM>) at the end of the program.

In another embodiment of the present invention, the laundry dryer (<NUM>) comprises a humidity sensor (<NUM>) which is provided in the body (<NUM>) and which measures the humidity of the laundry, and the control unit (<NUM>) which turns off the UV light source (<NUM>) if the value received from the humidity sensor (<NUM>) falls below a value predetermined by the producer. The humidity sensor (<NUM>) is positioned in the body (<NUM>) so as to contact the laundry. It is decided that the laundry is dry when the value received from the humidity sensor (<NUM>) falls below a value predetermined by the producer. The drying process is ended and the UV light source (<NUM>) is turned off after the control unit (<NUM>) detects that the laundry is dry. Thus, the user is prevented from being exposed to UV light while he/she takes the laundry out of the drum (<NUM>) after the drying process is ended.

In an embodiment of the present invention, the laundry dryer (<NUM>) comprises the control unit (<NUM>) which does not allow the operation of the UV light source (<NUM>) if the temperature value received from the second temperature sensor (<NUM>) is below <NUM><NUM> C. The UV light source (<NUM>) operates at low levels of radiation at temperatures under <NUM><NUM> C, and the sterilization effect thereof becomes significantly inefficient. Therefore, the control unit (<NUM>) does not operate the UV light source (<NUM>) if the temperature value received from the second temperature sensor (<NUM>) is below <NUM><NUM> C. Thus, the energy saving of the laundry dryer (<NUM>) is increased.

In an embodiment of the present invention, the first threshold value is between <NUM><NUM> C and <NUM><NUM> C. In the laundry dryer (<NUM>) operated in an environment at the room temperature, the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) at the end of the first period of time is approximately <NUM><NUM> C. In the laundry dryer (<NUM>) operated in an environment with an ambient temperature of approximately <NUM><NUM> C, the difference between the temperature value received from the first temperature sensor (<NUM>) and the temperature value received from the second temperature sensor (<NUM>) at the end of the first period of time is approximately <NUM><NUM> C. In a preferred embodiment of the present invention, the first threshold value is <NUM><NUM> C.

In an embodiment of the present invention, the second threshold value is between <NUM><NUM> C and <NUM><NUM> C. In the laundry dryer (<NUM>) operated in an environment at the room temperature, the temperature value received from the second temperature sensor (<NUM>) at the end of the first period of time is <NUM><NUM> C while in the laundry dryer (<NUM>) operated in an environment with an ambient temperature of approximately <NUM><NUM> C, the temperature value received from the second temperature sensor (<NUM>) at the end of the first period of time is <NUM><NUM> C. In a preferred embodiment of the present invention, the second threshold value is <NUM><NUM> C.

Claim 1:
A laundry dryer (<NUM>) comprising a body (<NUM>); a drum (<NUM>) which is disposed in the body (<NUM>) and wherein laundry is loaded; an air circulation duct (<NUM>) which provides delivery of drying air into the drum (<NUM>); a compressor (<NUM>) which is disposed in the body (<NUM>) and which provides a refrigerant cycle; a first temperature sensor (<NUM>) which is disposed on the compressor (<NUM>) and which measures a temperature of the compressor (<NUM>); a second temperature sensor (<NUM>) which is disposed in the air circulation duct (<NUM>) and which measures a temperature of the air drawn from the drum (<NUM>); and a UV light source (<NUM>) which is disposed in the body (<NUM>) and which emits UV light into the drum (<NUM>), the laundry dryer (<NUM>) further comprising:
- a control unit (<NUM>) configured to operate the UV light source (<NUM>) when a temperature value received from the second temperature sensor (<NUM>) is above <NUM><NUM> C and to turn off the same when said temperature value is above <NUM><NUM> C if a difference between a temperature value received from the first temperature sensor (<NUM>) and a temperature value received from the second temperature sensor (<NUM>) is above a first threshold value predetermined by the producer and if a temperature value received from the second temperature sensor (<NUM>) is above a second threshold value predetermined by the producer after the compressor (<NUM>) is operated for a first period of time predetermined by the producer.