Description A WASHER/DRYER AND A CONTROL METHOD
[001] This invention is related to a washer/dryer and a control method which utilizes microwaves wherein burning incidences that can occur in the laundry are detected before they take place.
[002] A magnetron which produces microwave energy and a drum wherein the laundry is placed is present in washer/dryers which utilize microwaves. When the microwave energy is directed towards the laundry inside the drum during the drying process, a formation of an arc occurs between metal objects such as metal zips, buttons, and keys left inside the pockets etc. As a result of the the arcs and/or microwave 'energy appear the partial heating effect cause the laundry to turn yellow, to melt and to burn.
[003] In the American Patent No US 5606804, the laundry is dried by using microwave energy and hot air circulation at the same time. The different gas sensors placed inside the air canals which lets the hot air out of the system detect the gases coming out of the laundry when burning starts and the drying process is halted.
[004] The object of this invention is to realize a washer/dryer and a control method which utilizes microwaves wherein burning, yellowing or melting incidences that can occur in the laundry during the drying cycle are determined before they take place.
[005] A washer/dryer and a control method realized in order to attain the objects of the 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 schematic view of a washer/dryer control method. [008] The components in the figures have each been numbered corresponding the following: Washer/dryer Tub Drum Circulation canal Magnetron Control unit Wave guide Condenser Fan 10 Heater 11 Tub outlet 12 Tub inlet 13 Gas sensor 14 Temperature sensor 15 Moisture sensor
[009] A washer/dryer (1) which utilize microwaves comprises a drum (3) wherein the laundry to be washed is placed, a tub (2) wherein the drum moves, a magnetron (5) which applies microwave energy in order to vaporize the water content inside the ■ laundry, a control unit (6) which regulates functioning by evaluating the data regarding the condition of washing/drying, a wave guide (7) which directs the microwaves towards on the laundry, a condenser (8) which ensures the moisture in the air to be separateed by condensing, a fan (9) which enables air circulation in the drying cycle, a heater (10) which provides heat energy together with microwave energy to accelerate the drying process or when microwave energy is not used in the drying cycle, a tub outlet (11) through which the moisture in the air is absorbed 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) wherein the drying cycle air is circulated, one or more gas sensors (13) which are placed inside the circulation canal (4), which detect gasses such as, methane, propane, butane etc. that appear in conditions where yellowing or burning of the laundry could occur, which enable halting the drying process by warning with the control unit (6) when the gas quantity exceeds the limit value where there is a burning, yellowing and melting risk for the laundry, a moisture sensor (15) which is placed inside the circulation canal (4), which measures the moisture value of the air circulating in the drying cycle, which enables halting the drying process by warning with the control unit (6) when the amount of dryness exceeds the limit value could be a risk for the laundry and a temperature sensor (14) which is placed inside the circulation canal (4), which measures the temperature of the air circulating in the drying cycle, which enables halting the drying process by warning with the control unit (6) when the temperature exceeds the limit value where there is a burning, yellowing and melting risk for the laundry.
[010] The gas sensor (13), the temperature sensor (14) and the moisture sensor (15) are placed inside the circulation canal (4) preferably after the condenser (8) and in between the fan (9) and the magnetron (5) in such a way that they are least effected from the heater (10) and the condenser (8).
[011] When the washer/dryer is operated, the gas sensor (13), the temperature sensor (14) and the moisture sensor (15) send to the control unit (6) the measurement results they obtained during the drying phase. By using the data obtained from the sensors (13, 14 and 15), the control unit (6) monitors to make sure the laundries reach the desired dryness and by haltinging the drying process it prevents yellowing, burning or melting which might occur in laundries. The dryness level of the laundries is monitored with the moisture sensor (15) and gasses that might appear when burning or yellowing occurs are detected with the gas sensors (13). The temperature sensor (14) is the final control point for preventing burning, yellowing and melting and it functions as a safety valve.
[012] When the said washer/dryer which utilizes microwaves is controlled the phrases
below are defined as: [013] hi : the instant moisture quantity of the air circulated in the drying cycle;
[014] h_limitl : the moisture value which indicates the desired dryness level of the laundries; [015] gl : the instant gas quantity comprised in the air circulated in the drying cycle;
[016] #g: the change quantity of the instant gas quantity (gl);
[017] #g_limit: the limit change quantity which shall not be exceeded in order to prevent the laundries from turning yellow or burning; [018] T 1 : the instant temperature of the air circulated in the drying cycle;
[019] T imit: the limit temperature value which shall not be exceeded in order to prevent the laundries from melting, turning to yellow or burning. [020] In the said washer/dryer which utilizes microwaves, the control method which detects burning incidences before they take place during the drying process of the laundries is composed of the following steps: - Starting the drying process (101), - Measuring, by means of a moisture sensor (15) the instantmoisture quantity (hi) of the air circulated in the drying cycle (102), - Comparing the instant moisture quantity (hi) with the moisture value (h_limitl) which indicates the desired dryness level of the laundries (103), - Halting the drying process if the instant moisture quantity (hi) greater than the moisture value (h_limitl) which indicates the desired dryness level of the laundries (108), - Measuring the instant gas quantity (gl) comprised in the air circulated in the drying cycle if the instant moisture quantity (hi) is less than the moisture value (h_limitl) which indicates the desired dryness level of the laundries (104), - Calculating, with the control unit (6), the quantity change(#g) of the instant gas quantity (gl) (105), - Comparing the quantity change (#g) of the instant gas quantity (gl) with the quantity change limit (#g_limit) which shall not be exceeded in order to prevent the laundries from turning yellow or burning (106), - Halting the drying process if the quantity change (#g) of the instant gas quantity (gl) greater than the quantity change limit (#g_limit) which shall not be exceeded to prevent the laundries from turning to yellow or burning (109),
- Measuring, with the temperature sensor (14), the instant temperature (Tl) of the air circulated in the drying cycle if the quantity change (#g) of the instant gas quantity (gl) is less than the quantity change limit (#g_limit) which shall not be exceeded in order to prevent the laundries from turning yellow or burning (107),
- Comparing the instant temperature (Tl) with the limit temperature value (T_limit) which shall not be exceeded in order to prevent the laundries from melting, turning yellow or burning (108),
- Halting the drying process if the instant temperature (Tl) greater than the limit temperature value (T_limit) which shall not be exceeded in order to prevent the laundries from turning yellow or burning (109),
- Returning back to the step where the moisture quantity (hi) is measured with the moisture sensor (15) if the instant temperature (Tl) is less than the limit temperature value (T_lim.it) which shall not be exceeded in order to prevent the laundries from turning yellow or burning (102). Using the gas sensor (13), the temperature sensor (14) and the moisture sensor (15) placed in the circulation canal (4) the dryness of the laundries in the drying cycle and burning or melting incidences before they take place are detected.