A LAUNDRY DRYER HAVING A SELF CLEANING LINT FILTER

[0001] The present invention relates to a laundry dryer comprising a filter that holds the lint and fluff particles in the drying air.

[0002] In closed cycle laundry dryers, the condensers of which are cooled with air, the drying process is provided with the interaction between the cooling air and the cycle air that do not directly contact each other. The cycle air is heated by a heater and directed into the drum, which then contacts the damp laundry and removes the moisture on the laundry and which is finally transferred to a condenser to be dehumidified. Meanwhile, the cooling air is sent onto the condenser by means of a fan and thus, the moisture in the cycle air is provided to be condensed by the condenser being cooled. After the cycle air is dehumidified on the condenser, it is heated by the heater and sent to the drum by being put again into the drying cycle with low relative humidity rate and at high temperature. During this cycle of air, lint particles come off the laundry and these lints should be filtered before reaching the heater. Therefore, in laundry dryers, a filter is disposed on the air circulation path in order to filter these lints.

[0003] In some of the state of the art laundry dryers, a filter is disposed onto the condenser and the lints on the cycle air reaching the condenser do not stick on the filter. However, lints gradually accumulate on the filter during operation and makes the circulation of the air difficult. As a result of this, the energy consumption of the dryer increases and the drying efficiency decreases. Consequently, these filters have to be cleaned automatically or by the user at certain intervals. Manual cleaning is an application preferred by the user.

[0004] In the state of the art French Patent Application No FR2533141 , the lints collect on a filtering element that rotates around rollers and the collected lints are removed by a cleaning brush.

[0005] The aim of the present invention is the realization of a laundry dryer having a self cleaning filter that holds the particles in the drying air.

[0006] The laundry dryer realized in order to attain the aim of the present

invention is explicated in the attached claims. [0007] The laundry dryer comprises a filter on the circulation channel, through which the cycle air passes. While the filter is in the first position, it is on the circulation channel, on the condenser surface through which the cycle air enters, and provides the lints in the cycle air to be collected. While the filter is in the second position, it is on the cooling channel, on the condenser surface through which the cooling air leaves. A movement mechanism brings the filter to the second position from the first position.

[0008] The cycle fan providing the cycle air to be circulated and the cooling fan providing the cooling air to be blown are controlled by a control unit. In an embodiment of the present invention, the control unit turns off the fans after the drying process is over, and operates the cooling fan after the movement mechanism brings the filter, the surface of which is filled with lints, onto the cooling channel. In another embodiment of the present invention, the control unit operates both fans after bringing the filter to the second position. After the drying process is over, no filter is required on the circulation channel during filter cleaning. One side of the filter faces the condenser in both positions. In the first position, while the air entering the condenser passes through the filter, the lints cling to the filter surface that does not face the condenser. When the filter is brought to the second position, lints are situated on its surface that does not face the condenser. When the cooling fan is operated, the air enters the filter from its surface facing the condenser, and exits through its surface whereon lints are situated, collecting the lints. Thus, the lints are moved away from the filter without requiring user intervention.

[0009] In an embodiment of the present invention, the laundry dryer comprises a lint bag which is located after the condenser and through which air can pass. When the filter is brought to this surface to be cleaned, the lints coming off the laundry accumulate in the lint bag.

[0010] In an embodiment of the present invention, when a number of cycles

prestored in the control unit is reached, the control unit provides the user to be warned to replace the lint bag.

[001 1] In another embodiment of the present invention, the control unit comprises two sensors, one of which is before the condenser in the cooling channel and the other after the lint bag in the cooling channel. The increasing of the temperature after the lint bag indicates that the lint bag is full and hence the cooling air cannot pass through the lint bag. The control unit compares the temperature measured by the sensor before the condenser and the temperature measured by the sensor after the lint bag and thus, warns the user when the lint bag is required to be replaced.

[0012] In an embodiment of the present invention, the laundry dryer has a

scraper, with which the filter makes contact while changing from the first position to the second position. Thus, the lints on the filter are collected together or fall off by means of the scraper and their discharge is facilitated.

[0013] In an embodiment of the present invention, the laundry dryer comprises an opening in the circulation channel. The opening is insulated by a sealing element which is disposed such that it will not prevent the filter from passing to the cooling channel from the circulation channel and will prevent the air from exiting.

[0014] In an embodiment of the present invention, the sealing element is

configured as a spring roller which rotates while the filter passes thereon.

[0015] By means of the movement mechanism of the present invention, the filter collects the lints in the circulation channel during the cycle, and is cleaned by being brought to the flow line of the cooling air, to the cooling channel at the end of the cycle. By means of the control unit, the cooling fan and cycle fan are controlled, and the cooling fan is operated during cleaning of the filter. Accordingly, the filter can be self cleaned without requiring the user to take out the filter.

[0016] A laundry dryer realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

[0017] Figure 1 - is the schematic view of a laundry dryer.

[0018] Figure 2 - is the exploded view of the condenser and the filter in an

embodiment of the present invention.

[0019] Figure 3 - is the schematic view of the filter while on the circulation

channel in an embodiment of the present invention.

[0020] Figure 4 - is the schematic view of the filter while on the cooling channel in an embodiment of the present invention.

[0021] Figure 5 - is the schematic view of the filter on the circulation channel while being moved onto the cooling channel in another embodiment of the present invention.

[0022] The elements illustrated in the figures are numbered as follows:

1. Laundry dryer

2. Drum

3. Circulation channel

4. Condenser

5. Cycle fan

6. Cooling fan

7. Cooling channel

8. Filter

9. Movement mechanism

10. Control unit

1 1. Lint bag

12. Scraper

13. Sealing element

14. Sensor

15. Heater

[0023] The laundry dryer (1) comprises a body,

- a drum (2) wherein the laundry desired to be dried is placed,

- circulation channel (3) through which the cycle air passes,

- a condenser (4) which is located in the circulation channel (3) and

provides the cycle air to be dehumidified by being condensed,

- a heater (15) which is located in the circulation channel (3), provides the dehumidified cycle air exiting the condenser (4) to be heated,

- at least one cycle fan (5) which is located in the circulation channel (3) and provides the circulation of the cycle air,

- a cooling fan (6) which provides the cooling air aspirated from the

ambient to be blown onto the condenser (4) in order that the condenser (4) can be cooled,

- a cooling channel (7) which extends between the condenser (4) and the cooling fan (6), and through which the cooling air passes, and

- a filter (8) which is disposed into the circulation channel (3) before the condenser (4) according to the direction of the flow and which collects the lints located in the cycle air

[0024] (Figure 1).

[0025] In the laundry dryer (1 ), the cycle air is sent to the drum (2) after being passed over the heater (15). The hot air dehumidifies the laundry in the drum (2) and exits the drum (2). Meanwhile, small lint pieces coming off the laundry mix with the cycle air. The cycle fan (5) absorbs the air exiting the drum (2) and transmits it to the condenser (4). The filter (8) located before the condenser (4) prevents the lints from entering the condenser (4) and getting wet. The cooling fan (6) which blows the cool air in the outer environment to the condenser (4) provides that the moisture stays on the condenser (4) by cooling the humid and hot cycle air which passes through the condenser (4) and also provides that the cycle air exits the condenser (4) in a dry state. While the cycle air proceeds through the circulation channel (3), the cooling air passes through the cooling channel

(7) and these two airs do not mix with each other. The cycle fan (5) completes the drying cycle by transmitting the dry cycle air exiting the condenser (4) to the heater (15) once again and then to the drum (2). Each time the cycle air passes through the drum (2), it holds some amount of lint on the laundry. By means of these lints being filtered by the filter (8) before the condenser (4) that is located before the heater (15), they are prevented from reaching the heater (15).

[0026] The laundry dryer (1), furthermore, comprises a filter (8) which is located before the condenser (4) in the circulation channel (3) in the first position and located after the condenser (4) in the cooling channel (7) in the second position, and a movement mechanism (9) which moves the filter

(8) between the first position and the second position (Figures 3, 4 and 5).

[0027] In an embodiment of the present invention, the laundry dryer (1 ) comprises a control unit (10) which operates the cooling fan (6) and stops the cycle fan (5) after the movement mechanism (9) brings the filter (8) to the second position (Figure 1 ). In another embodiment of the present invention, the control unit (10) operates the cooling fan (6) and the cycle fan (5) together while the filter (8) is in the second position.

[0028] While the cycle fan (5) is operating, the filter (8) is inside the circulation channel (3) in its first position and collects the lints in the cycle air. The filter (8) is preferably formed as a quadrilateral cloth and has two surfaces (A and B) (Figure 2). During the cycle, the cycle fan (5) and the cooling fan (6) operate together. Meanwhile, the lints in the cycle air accumulate on the filter (8) surface (A), through which the air enters. The filter (8) can be cleaned only after the cycle is over. When the filter (8) is to be cleaned, the movement mechanism (9) brings the filter (8) to the second position. The control unit (10) operates the cooling fan (6) for the filter (8) cleaning process. Meanwhile, the cooling air enters the filter (8) through its surface (B), on which there is no lint, and exits through its surface (A), on which there is lint. Since air flow enters through the surface (B), on which there is no lint, the lints cannot cling to the surface (A) they are situated on. Thus, the filter (8) is cleaned without requiring user intervention (Figure 3 and Figure 4).

[0029] In an embodiment of the present invention, the condenser (4) is shaped as a rectangular prism, and its two opposite surfaces X and Y are on the circulation channel (3) and its other two opposite surfaces Z and T are on the cooling channel (7) (Figure 2). The cycle air entering through surface X exits through surface Y which is located opposite surface X. The cooling air enters through surface Z, which is vertical to surfaces X and Y, and exits through surface T, which is located opposite surface Z. The filter (8) that stands almost on surface X in the first position is brought onto surface Z in the second position.

[0030] In an embodiment of the present invention, the movement mechanism (9) comprises two rollers, one of which is located on the circulation channel (3) and the other on the cooling channel (7), and a motor which provides the filter (8) to be wound onto the rollers by rotating the rollers. While the motor rotates the rollers in the same direction, the filter (8) moves between the two positions towards the rotational direction of the rollers.

[0031] In an embodiment of the present invention, the movement mechanism (9) is a step motor which brings the filter (8) to the second position from the first position, and which brings the filter (8) again to the first position by rotating in the opposite direction after the filter (8) cleaning process is over. The step motor, which is a simple and small motor, can move the filter (8) back and forth by the gear located at its center being rotated by means of the electromagnets around it.

[0032] In an embodiment of the present invention, the laundry dryer (1 ) comprises a lint bag (1 1) which is disposed after the condenser (4) and collects the lints that are freed from the filter (8) by the cooling air (Figures 3, 4 and 5). The filter (8) enters between the lint bag (1 1 ) and the condenser (4) by snap fitting. While the lint bag (1 1 ) allows the cooling air to pass during the cycle, it has holes small enough to filter the lints coming off the filter (8) during filter (8) cleaning and to allow the cooling air to pass. The ling bag (1 1 ) is full after the filter (8) is cleaned many times, and is being replaced by the user.

[0033] In an embodiment of the present invention, the control unit (10) controls the number of drying cycles and warns the user for the cleaning of the lint bag (1 1 ) when a number prestored in its memory is reached. As a result of the tests performed, the manufacturer determines after how many cycles the lint bag (1 1 ) is full. The control unit (10) warns the user to replace the lint bag (1 1 ) when this number of cycles prestored in its memory is reached. The warning can be performed audibly or visually.

[0034] In another embodiment of the present invention, the laundry dryer (1)

comprises two temperature sensors (14), one of which is disposed before the condenser (4) into the cooling channel (7) and the other after the lint bag (1 1 ) into the cooling channel (7). The control unit (10) detects that the lint bag (1 1 ) is required to be cleaned by checking the difference in temperature measured by the sensors (14) and warns the user. The flow of the cooling air decreases as the lint bag (1 1) fills. Therefore, a

temperature difference occurs and the temperature after the lint bag (1 1 ) increases since the air that enters the condenser (4) in a cool state cannot exit. Since the amount of lints coming off different types of laundry is different, it is safer to utilize sensors (14) independently of the number of cycles.

[0035] In an embodiment of the present invention, the laundry dryer (1 ) comprises a scraper (12) which is disposed onto the condenser (4) surface (T), through which the cooling air exits, and which scrapes the lints on the filter (8) while the movement mechanism (9) moves the filter (8) between the first position and the second position (Figure 4). The scraper (12) contacts the filter (8) while the filter (8) loaded with lint is being pulled to this surface, and provides some amount of the lints to fall off. By operating the cooling fan (6), the cooling air blown onto the filter (8) moves the lints away from the filter (8) more easily.

[0036] In an embodiment of the present invention, the laundry dryer (1 ) comprises an opening (O) which is located on the circulation channel (3) and through which the filter (8) passes, and a sealing element (13) which covers the opening (O) such that no air but the filter (8) will pass therethrough.

[0037] In an embodiment of the present invention, the sealing element (13) is configured as a spring roller such that it will apply pressure onto the filter (8) (Figure 4). While the sealing element (13) configured as a spring roller passes over the filter (8), it rotates and thus, facilitates the passage of the filter (8) and at the same time provides sealing here.

[0038] By means of the present invention, the user is not required to clean the filter (8) after each drying process and the lints accumulating on the filter (8) are moved away from the filter (8) by the filter (8) being brought to the cooling channel (7) by means of the movement mechanism (9).

[0039] It is to be understood that the present invention is not limited to the

embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These should be considered within the scope of the protection postulated by the claims of the present invention.