[002] In washer/dryers, drying period is one of the important variable during the drying process. Drying period affects both the energy consumption values and the moisture amount in the dried laundry. In conventional washer/dryers, the drying period is determined by the user and drying is performed during the selected duration. Drying level of the laundry is measured to lower the energy consumption values and end the drying process when the laundry reach at the required drying level.

[003] American Patent 5347727 detects the amount of the laundry and the period when the drying process is ended by the temperature and moisture sensors in the air canal.

[004] The object of this invention is to realize a control method for a washer/dryer for providing the efficient determination of the time when the dried laundry reach at the required drying level.

[005] The control method for a washer/dryer realized in order to attain above mentioned objects of the present invention has been illustrated in the attached drawings, wherein [006] Figure 1 is a schematic view of a washer/dryer.

[007] Figure 2 is a flow chart of a control method for a washer/dryer.

[008] Figure 3 is a flow chart of another control method for a washer/dryer.

[009] The components shown in the figures have been enumerated as below: 1. Washer/dryer 2. Tub 3. Drum 4. Circulation canal 5. Temperature sensor 6. Control unit 7. Moisture sensor 8. Condenser 9. Fan 10. Heater 11. Tub outlet 12. Tub inlet 13. Condenser valve [010] A washer/dryer (1) comprises a drum (3) in which the laundry is placed, a tub (2) in which the drum (3) moves, a control unit (6) which evaluates the data related to the washing/drying conditions and regulates the operation, a condenser (8) which ensures the moisture in the air to be separated by condensing, a fan (9) which provides the circulation of the air in the drying cycle, a heater (10) which provides the heating energy in the drying cycle, a tub outlet (11) through which the moisture in the air is sucked from the tub (2), a tub inlet (12) through which the moisturless and heated air is delivered again to the tub (2), a circulation canal (4) in which the air of the drying cycle circulates, a moisture sensor (7) which is placed into the circulation canal (4) and measures the moisture level of the air in the drying cycle, a temperature sensor (5) which is placed into the circulation canal (4) and measures the temperature of the air in the drying cycle and a condenser valve (13) which controls the transfer of the cooling fluid which will be use in the condenser (8), for instance water to the condenser (8).

[011] Temperature sensor (5) and moisture sensor (7) are placed into the circulation canal (4) preferably after the condenser (8) and the fan (9) to be least effected by the heater (10) and the condenser (8).

[012] When the washer/dryer is operated, the fan (9) and the heater (10) is operated, the drying air in the circulation canal (4) is heated over the heater (10) by means of the fan (9) and reached to the tub (2) and the drum (3) through the tub inlet (12). The drying air contacts with the laundry in the drum (3), takes away some of the moisture they contain and returns to the circulation canal (4) from the tub outlet (11). Simultaneously the condenser valve (13) is opened and closed by the control unit (6) according to the period determined by the manufacturer and the water is filled into the condenser (8).

When the drying air contacts with the surface of the condenser (8), it leaves the moisture inside onto the condenser (8) as a result of the change in temperature. The drying air is later subjected to the same cycle by the fan (9) until the required drying level is reached. Temperature sensor (5) and moisture sensor (7) send the measurement results of the drying cycle to the control unit (6). Moisture sensor (7) measures the instant moisture values of the drying air. Instant moisture values have instant decreases which is the during the opening of the condenser valve (13) and increases which is the during the closing of the condenser valve (13). The amplitude of the decreases when the condenser valve (13) is opened increases during the drying. Control unit (6) monitors the drying level by means of the data received from the sensors (5 and 7) and interrupts the drying cycle when the required drying level is achieved.

[013] When the said washer/dryer is controlled, those indicate the following: [014] hl : instant moisture amount of the air circulating in the drying cycle before the condenser valve (13) is opened.

[015] h2: instant moisture amount of the air circulating in the drying cycle before the condenser valve (13) is closed.

[016] h limit : limit difference value indicating that the required drying level is achieved.

[017] #h : difference between the instant moisture amount of the air circulating in the drying cycle before the condenser valve (13) is opened and the instant moisture amount of the air circulating in the drying cycle before the condenser valve (13) is closed.

[018] T1 : instant temperature of the air circulating in the drying cycle.

[019] T limit : limit temperature value when the need of condensation starts.

[020] Theating: heating period when only the fan (9) and the heater (10) are used when the condenser (8) is not operated.

[021] The control method which is used for the determination of achievement of the required drying level comprises the following steps (Figure 2): - starting the drying process (101), - measuring the instant moisture amount (hl) of the air circulating in the drying air by the moisture sensor (7) just before the condenser valve (13) is opened (102), - providing the condenser (8) with the water by opening the condenser valve (13) (103), - measuring the instant moisture amount (h2) of the air circulating in the drying air by the moisture sensor (7) just before the condenser valve (13) is closed (104), - closing the condenser valve (13) (105), - calculating the difference (#h) between the instant moisture amount (hl) of the air circulating in the drying air just before the condenser valve (13) is opened and the instant moisture amount (h2) of the air circulating in the drying air just before the condenser valve (13) is closed (106), comparing the difference (#h) between the instant moisture amount (hl) of the air circulating in the drying air just before the condenser valve (13) is opened and the instant moisture amount (h2) of the air circulating in the drying air just before the condenser valve (13) is closed with the limit difference value (h limit) indicating that the required drying level is achieved (107), halting the drying process (109) if the difference (#h) between the instant moisture amount (hl) of the air circulating in the drying air just before the condenser valve (13) is opened and the instant moisture amount (h2) of the air circulating in the drying air just before the condenser valve (13) is closed is greater than the limit difference value (limit) indicating that the required drying level is achieved (109), - continuing the drying process by operating the fan (9), the heater (10), and the drum (3) in the required combination for a specific time, if the difference (#h) between the instant moisture amount (hl) of the air circulating in the drying air just before the condenser valve (13) is opened and the instant moisture amount (h2) of the air circulating in the drying air just before the condenser valve (13) is closed is lower than the limit difference value (hjimit) indicating that the required drying level is achieved (108), Returning to the step (102) of measuring the instant moisture amount (hl) of the air circulating in the drying air by the moisture sensor (7) just before the condenser valve (13) is opened.

[022] In another embodiment of the invention, in washer/dryers, after the drying process is started (101) and before the condenser valve (13) is opened (103), the control method which is used for the determination of achievement of the required drying level comprises the following steps (Figure 3): - operating the fan (9) and the heater (10) (201), - measuring the instant temperature (Tl) of the air circulating in the drying cycle by means of the temperature sensor (5) (202), - comparing the instant temperature (Tl) with the limit temperature value (T limit) when the need of condensation is started (203), - returning to the step (202) of measuring the instant temperature (T1) of the air circulating in the drying cycle by means of the temperature sensor (5), if the instant temperature (T1) is lower than the limit temperature value (T limit) when the need of condensation is started, - calculating the heating period (Theating) in which only the fan (9) and the heater (10) are used by the control unit (6) before the condenser (8) is operated if the instant temperature (T1) is higher than the limit temperature value (T limit) when the need of condensation is started (204), - estimating the amount of laundry by using the data related to the heating period (Theating) in which only the fan (9) and the heater (10) before the condenser (8) is operated and calculating limit difference value (limit) indicating whether the required drying level is achieved depending on the amount of the laundry (205) and returning to the step of measuring the instant moisture amount (hl) of the air circulating in the drying air by the moisture sensor (7) just before the condenser valve (13) is opened (102).

[023] The drying level of the laundry is detected by monitoring the changes in the moisture values in the drying air when the condenser valve (13) is opened and closed, and drying period is optimized.