Drying air duct, washer-dryer and control method of washer-dryer

Abstract

The present invention discloses a drying duct, a washing and drying machine, and a control method for the washing and drying machine. A filter is provided in the drying duct to cover the air outlet of the drying duct, and a detection device for detecting the blockage area of ​​the filter is provided on the filter. A detection device is provided on the filter, and the blockage area of ​​the filter after being blocked by debris can be detected by the detection device. According to the blockage area of ​​the filter, the filter is cleaned in time to increase the heat exchange capacity of the heat exchanger, thereby improving the drying efficiency of the washing and drying machine; the washing and drying machine is provided with a drying duct and a cleaning device for cleaning the filter in the drying duct. The control method of the washing and drying machine includes detecting the blockage area of ​​the filter, obtaining the actual blockage area of ​​the filter, comparing the actual blockage area of ​​the filter with a first set value, and cleaning the filter if the actual blockage area of ​​the filter is greater than the first set value.

Description

Technical Field

[0001] The present invention belongs to the field of washer-dryers, and in particular relates to a drying air duct, a washer-dryer and a control method for the washer-dryer. Background Art

[0002] A washer-dryer has two functions: washing and drying. When performing the drying function, the washer-dryer uses electric heating or a heat exchanger (heat pump type) to generate a high-temperature air flow to evaporate the moisture in the washed clothes immediately. The washer-dryer includes a clothes tub for holding clothes, which is connected to an air duct. The air duct is equipped with a fan and a heat exchanger. When the washer-dryer washes and dries clothes, the clothes will produce a lot of debris such as lint. When the washer-dryer runs the drying program, the fan will blow hot dry air into the washer-dryer tub, and the wet air will be recovered from the tub and enter the heat exchanger for heat exchange and drying, forming an air circulation. In order to avoid reducing the drying efficiency, a filter is often installed in the air duct. The filter is set in front of the heat exchanger to prevent lint and other debris from entering the heat exchanger and affecting the operation of the heat exchanger.

[0003] However, when debris such as lint accumulates on the filter, it will affect the air intake and directly affect the heat exchange, thereby reducing the drying efficiency. At this time, if the blockage area of ​​the filter cannot be detected in time, the filter cannot be cleaned in time, which will increase the time required for users to dry clothes and cause user complaints.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the technical problem in the prior art that the blockage area of ​​the filter cannot be detected in time, resulting in the inability to clean the filter in time, and provide a drying duct, a washing and drying machine and a control method for the washing and drying machine to achieve the purpose of timely detecting the blockage area of ​​the filter and timely cleaning the filter to improve the drying efficiency.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0007] The invention provides a drying air duct. A filter screen for covering the air outlet of the drying air duct is provided in the drying air duct. A detection device for detecting the blockage area of ​​the filter screen is provided on the filter screen.

[0008] Furthermore, the detection device is a photoelectric sensor, and the transmitting end and the receiving end of the photoelectric sensor are relatively arranged on different sides of the filter.

[0009] Furthermore, the photoelectric sensor includes an infrared light emitting diode and a phototransistor, the infrared light emitting diode and the phototransistor are arranged on different sides of the filter, and the emitting end of the infrared light emitting diode is arranged opposite to the receiving end of the phototransistor.

[0010] The present invention also provides a washer-dryer, which is provided with a drying air duct provided by the above technical solution and a cleaning device for cleaning the filter screen in the drying air duct.

[0011] Furthermore, the cleaning device includes a first water pipe, a water storage tank arranged in the washing and drying machine, and a spray structure arranged in the drying air duct. The first water pipe is inserted into the drying air duct, and the water inlet of the first water pipe is connected to the water storage tank, and its water outlet is connected to the spray structure. A first control valve is connected in series to the spray structure, and the spray port of the spray structure is facing the filter.

[0012] Furthermore, a heat exchanger is provided in the drying duct, and a spray structure is provided at the top of the drying duct between the heat exchanger and the filter screen;

[0013] Preferably, the spray structure includes a vertical pipe and an inclined pipe. The vertical pipe is arranged at the top of the drying duct, and the water inlet of the vertical pipe is connected to the first water pipe, and its water outlet is connected to the water inlet of the inclined pipe. The water outlet of the inclined pipe is provided with a nozzle, the nozzle has a spray port, and the inclined pipe is inclined toward the filter screen.

[0014] Furthermore, a water tub is provided on the washing and drying machine, a drain pipe is provided at the bottom of the water tub, a drain valve is connected in series to the drain pipe, and the cleaning device also includes a second water pipe, the water inlet of the second water pipe is connected to the drain pipe and is located upstream of the drain valve, and its water outlet is connected to the water tank, a second control valve is connected in series to the second water pipe, and a liquid level detection component for detecting the liquid level is provided in the water tank.

[0015] The present invention also provides a control method for a washing and drying machine, which uses the washing and drying machine provided by the above technical solution to detect the filter blockage area, obtain the actual filter blockage area, compare the actual filter blockage area with a first set value, and if the actual filter blockage area is greater than the first set value, clean the filter.

[0016] Furthermore, the transmitting end of the photoelectric sensor transmits photoelectricity through the filter, and the receiving end of the photoelectric sensor receives the photoelectricity and obtains the photoelectric area of ​​the photoelectricity passing through the filter to obtain the actual photoelectric area. The actual photoelectric area ratio is inversely proportional to the actual filter blockage area ratio.

[0017] Furthermore, when the filter is in the initial state, the photoelectric area of ​​the photoelectricity passing through the filter obtained by the receiving end of the photoelectric sensor is the original photoelectric area, the actual photoelectric area ratio is the actual photoelectric area / original photoelectric area, and the actual filter blockage area ratio is the actual filter blockage area / original photoelectric area;

[0018] Preferably, if the actual filter blockage area is smaller than the second set value, the cleaning of the filter is stopped.

[0019] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0020] 1. A detection device is installed on the filter. The detection device is a photoelectric sensor. The photoelectric sensor can detect the blockage area of ​​the filter after it is blocked by debris. According to the blockage area of ​​the filter, the filter is cleaned in time to avoid affecting the air volume and causing the heat exchange rate of the heat exchanger to decrease, so that the washing and drying machine has high drying efficiency.

[0021] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0023] Figure 1 This is a schematic structural diagram of a drying air duct provided by an embodiment of the present invention;

[0024] Figure 2 This is a flow chart of a control method for a washer-dryer provided by an embodiment of the present invention.

[0025] In the figure: 1-drying air duct; 2-filter; 3-detection device; 31-photoelectric sensor; 311-infrared light emitting diode; 312-phototransistor; 4-cleaning device; 41-spray structure; 411-vertical pipe; 412-inclined pipe; 42-first control valve; 5-heat exchanger.

[0026] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0030] Example

[0031] like Figure 1 As shown, the present invention provides a drying air duct 1, in which a filter 2 for covering the air outlet of the drying air duct 1 is provided, and a detection device 3 for detecting the blockage area of ​​the filter 2 is provided on the filter 2.

[0032] In an embodiment of the present invention, an inspection device is provided on the filter 2. The inspection device can detect the blockage area of ​​the filter 2 after being clogged by debris. According to the blockage area of ​​the filter 2, the filter 2 is cleaned in a timely manner to avoid affecting the air volume and causing the heat exchange rate of the heat exchanger 5 to decrease, thereby improving the drying efficiency of the washing and drying machine.

[0033] The drying duct 1 is used for a washer-dryer or a dryer. If used for a washer-dryer, the washer-dryer includes a clothes tub. The drying duct 1 is connected to the clothes tub through the air outlet of the drying duct 1 and is used to supply air to the clothes tub to dry the clothes in the clothes tub.

[0034] like Figure 1 As shown, in the embodiment of the present invention, the detection device 3 is a photoelectric sensor 31 , and the transmitting end and the receiving end of the photoelectric sensor 31 are relatively arranged on different sides of the filter 2 .

[0035] In an embodiment of the present invention, the transmitting end and the receiving end of the photoelectric sensor 31 are relatively arranged on different sides of the filter 2, so that the transmitting end and the receiving end of the photoelectric sensor 31 are separated by a filter 2. This ensures that the light emitted by the transmitting end of the photoelectric sensor 31 can pass through the filter 2 and be received by the receiving end of the photoelectric sensor 31. The photoelectric area of ​​the light passing through the filter 2 is obtained and converted into an electrical signal. The receiving end of the photoelectric sensor 31 is connected to the control system of the washer-dryer itself. The photoelectric sensor 31 transmits the electrical signal to the control system, and the control system controls whether to clean the filter 2 according to the size of the photoelectric area.

[0036] In addition, the detection device 3 may also be other forms of sensors, as long as they can detect the clogging area of ​​the filter 2, they can be used as the detection device 3 of this embodiment;

[0037] The transmitting end and the receiving end of the photoelectric sensor 31 are arranged on different sides of the filter 2 . The transmitting end of the photoelectric sensor 31 or the receiving end of the photoelectric sensor 31 can be arranged on a side of the filter 2 close to the heat exchanger 5 .

[0038] like Figure 1 As shown, in an embodiment of the present invention, the photoelectric sensor 31 includes an infrared light emitting diode 311 and a phototransistor 312. The infrared light emitting diode 311 and the phototransistor 312 are arranged on different sides of the filter 2, and the emitting end of the infrared light emitting diode 311 is arranged opposite to the receiving end of the phototransistor 312.

[0039] In an embodiment of the present invention, the photoelectric sensor 31 includes an infrared light-emitting diode and a phototransistor 312. The infrared light-emitting diode 311 has an emitting end, the positive electrode of the infrared light-emitting diode 311 is connected to the power supply, and the negative electrode is grounded through a resistor; the phototransistor 312 has a receiving end, the collector of the phototransistor 312 is connected to the power supply, and the emitter is grounded through a resistor; an optical filter is provided in front of the phototransistor 312 for filtering light whose wavelength is not near the infrared wavelength; the detection device 3 also includes an alarm device for issuing an alarm signal indicating that the filter 2 is highly clogged when receiving an optical signal at the receiving end; the alarm device includes an inverting trigger and a light-emitting diode, the input end of which is connected to the emitter of the photosensitive transistor, and the output end is connected to the light-emitting diode, the positive electrode of the light-emitting diode is connected to the output end of the inverting trigger, and the negative electrode is grounded through a resistor.

[0040] After power is applied, the infrared light emitting diode 311 emits infrared invisible light with a wavelength of 800nm. The phototransistor 312 is a light detection component that is sensitive to infrared light. When the phototransistor 312 is exposed to infrared light, it has a low impedance, its collector and emitter are conductive, and the emitter outputs a high voltage signal. When it is not exposed to light, it has a high impedance, its collector and emitter are isolated, and the emitter outputs a low voltage signal.

[0041] like Figure 1 As shown, the present invention further provides a washer-dryer, which is provided with a drying air duct 1 provided by the above technical solution, and a cleaning device 4 for cleaning the filter screen 2 in the drying air duct 1.

[0042] In an embodiment of the present invention, when it is detected that the blockage area of ​​the filter 2 is greater than a certain set value, the control system of the washing and drying machine controls the cleaning device 4 to clean the filter 2 according to the blockage area of ​​the filter 2, thereby realizing automatic and timely cleaning of the filter 2, avoiding manual disassembly of the filter 2 to clean the filter 2, and saving time and effort.

[0043] Specifically, the cleaning device 4 includes a first water pipe, a water storage tank arranged in the washing and drying machine, and a spray structure 41 arranged in the drying air duct 1. The first water pipe is inserted into the drying air duct 1, and the water inlet of the first water pipe is connected to the water storage tank, and its water outlet is connected to the spray structure 41. A first control valve 42 is connected in series to the spray structure 41, and the spray port of the spray structure 41 is facing the filter 2.

[0044] The washer-dryer includes a shell, a water storage tank is arranged in the shell, and is used to store water and supply water to the spray structure 41. The water in the water storage tank can come from the outside, from the condensed water accumulated by the heat exchanger in the drying air duct. The washer-dryer is also provided with a collector for collecting condensed water, which is connected to the water storage tank and comes from the water discharged from washing and rinsing. The first water pipe can be a hose, which is convenient for the first water pipe to bend and extend in the shell and be inserted into the air duct. A water pump is connected in series to the first water pipe, and the water pump provides power for the first water pipe to send the water in the water storage tank into the spray structure 41; the spray The structure 41 is connected to the first water pipe, which transports the water in the water storage tank to the spray structure 41. The spray structure 41 sprays the water through the spray port toward the filter 2 to clean the filter 2. It should be noted that the air duct is provided with a water outlet, and the water outlet is connected in series with a water outlet pipe. The water outlet pipe discharges the water accumulated in the air duct after cleaning the filter 2 to the outside. The water outlet pipe can be directly connected to the outside of the housing, or the water outlet pipe is connected to the drain pipe of the washing and drying machine. The water outlet pipe is connected in series with a control valve. When cleaning the filter 2, the control system opens the control valve.

[0045] The first control valve 42 is connected to the control system of the washing and drying machine. When it is detected that the blockage area of ​​the filter 2 is greater than a certain set value, the control system controls the first control valve 42 to open, and the first water pipe sends the water in the water tank to the spray structure 41. When it is detected that the blockage area of ​​the filter 2 is less than a certain set value (the set value is less than the above set value), the control system controls the first control valve 42 to close, and the first water pipe stops sending the water in the water tank to the spray structure 41.

[0046] like Figure 1As shown, in the embodiment of the present invention, a heat exchanger 5 is further provided in the drying air duct 1 , and a spray structure 41 is provided at the top of the drying air duct 1 between the heat exchanger 5 and the filter 2 .

[0047] In the embodiment of the present invention, the spray structure 41 is provided on the drying air duct 1 between the heat exchanger 5 and the filter 2. That is, the filter 2 is provided in front of the spray structure 41. The filter 2 filters out debris to prevent the debris from directly contacting the spray structure 41 and clogging the spray structure 41.

[0048] The spray structure 41 is arranged at the top of the drying air duct 1, so that water flows from high to low to spray on the filter 2. The water flows from high to low, and relies on its own gravity to hit the filter 2 with great force, crushing and penetrating the more sticky debris on the filter 2, thereby improving the cleanliness of the filter 2.

[0049] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the spray structure 41 includes a vertical pipe 411 and an inclined pipe 412. The vertical pipe 411 is arranged at the top of the drying duct 1, and the water inlet of the vertical pipe 411 is connected to the first water pipe, and its water outlet is connected to the water inlet of the inclined pipe 412. The water outlet of the inclined pipe 412 is provided with a nozzle, and the nozzle has a spray port. The inclined pipe 412 is inclined toward the filter 2; the spray structure 41 includes a vertical pipe for installing the spray structure 41 at the top of the air duct and an inclined pipe 412 with a spray port. The vertical pipe provides a vertical water flow from top to bottom, and the inclined pipe 412 makes the spray port face the large-area filter 2, providing water flow toward the large-area filter 2, so that the water flow can flow from top to bottom while flushing the large-area filter 2, further improving the cleanliness of the filter 2.

[0050] In an embodiment of the present invention, a water tub is provided on the washing and drying machine, a drain pipe is provided at the bottom of the water tub, a drain valve is connected in series to the drain pipe, and the cleaning device 4 also includes a second water pipe, the water inlet of the second water pipe is connected to the drain pipe and is located upstream of the drain valve, and its water outlet is connected to the water tank, a second control valve is connected in series to the second water pipe, and a liquid level detection component for detecting the liquid level is provided in the water tank.

[0051] In an embodiment of the present invention, the water in the water storage tank may be water discharged after washing or rinsing. The inlet of the water storage tank is connected to the outlet of the second water pipe. The outlet of the second water pipe is connected in series to the drain pipe of the water holding tub. The water holding tub herein may be the aforementioned clothes holding tub, which can hold both clothes and wash water. The water holding tub may also simply be a tub for holding wash water. Specifically, the outlet of the second water pipe is connected in series to the drain pipe located upstream of the drain valve, so that when the washer-dryer is draining, the water can be discharged into the water storage tank rather than to the outside.

[0052] A liquid level detection component is provided in the water storage tank, which is controlled by the control system of the washing and drying machine and can be a liquid level meter or a flow sensor. The liquid level meter can be directly arranged on the top of the water storage tank, and the flow sensor can be arranged on the second water pipe located on the top of the water storage tank. Specifically, when the washing and drying machine executes a drainage procedure, the liquid level meter detects that the water level in the water storage tank is lower than a certain set value, the control system controls the drain valve to close and the second control valve to open at the same time, and the drain pipe stores water into the water storage tank through the second water pipe. When the liquid level meter detects that the water level in the water storage tank is higher than the set value, the control system controls the drain valve to open and the second control valve to close at the same time, and the drain pipe discharges the washing water to the outside, thereby saving water resources.

[0053] It should be noted that a turbidity sensor is provided in the drain pipe upstream of the drain valve for detecting the turbidity of the water discharged for washing or rinsing. If the turbidity of the water is small, the control system controls the drain valve to close and the second control valve to open to allow water to flow into the water tank, so that the turbidity of the water in the water tank is small and does not affect the cleaning of the filter 2.

[0054] like Figure 2 As shown, the present invention also provides a control method for a washing and drying machine, which adopts the washing and drying machine provided by the above technical solution, detects the blockage area of ​​the filter 2, obtains the actual blockage area of ​​the filter 2, compares the actual blockage area of ​​the filter 2 with a first set value, and if the actual blockage area of ​​the filter 2 is greater than the first set value, cleans the filter 2.

[0055] In an embodiment of the present invention, the photoelectric sensor 31 detects the blockage area of ​​the filter 2 and transmits the blockage area signal of the filter 2 to the control system. The control system compares the blockage area of ​​the filter 2 with the first set value to determine whether to clean the filter 2. If the blockage area of ​​the filter 2 is greater than the first set value, the filter 2 is cleaned. By detecting the blockage area of ​​the filter 2 in real time, the filter 2 can be cleaned in time. As the filter 2 is continuously cleaned, when it is detected that the actual blockage area of ​​the filter 2 is less than the second set value, the cleaning of the filter 2 is stopped, and the second set value is less than the first set value.

[0056] In an embodiment of the present invention, the transmitting end of the photoelectric sensor 31 transmits photoelectricity through the filter 2, and the receiving end of the photoelectric sensor 31 receives the photoelectricity and obtains the photoelectric area through which the photoelectricity passes through the filter 2 to obtain the actual photoelectric area. The actual photoelectric area ratio is inversely proportional to the actual filter 2 blockage area ratio.

[0057] In the embodiment of the present invention, the photoelectric area of ​​the light passing through the filter 2 is first obtained, and then the blockage area of ​​the filter 2 is obtained based on the photoelectric area of ​​the light passing through the filter 2. Since the photoelectric area of ​​the light passing through the filter 2 is constant when the filter 2 is in the initial state, as the debris continues to accumulate, the photoelectric area of ​​the light passing through the filter 2 increases, resulting in a smaller blockage area of ​​the filter 2.

[0058] Specifically, when the filter 2 is in the initial state, the receiving end of the photoelectric sensor 31 obtains the photoelectric area of ​​the photoelectric light passing through the filter 2 as the original photoelectric area, the actual photoelectric area ratio is the actual photoelectric area / original photoelectric area, and the actual filter 2 blockage area ratio is the actual filter 2 blockage area / original photoelectric area, that is, the sum of the filter 2 blockage area and the photoelectric area is equal to the original photoelectric area.

[0059] The control process of the control method of the washing and drying machine is as follows: when the filter 2 of the washing and drying machine is in the initial state, there is no debris on the filter 2 at this time, the transmitting end of the photoelectric sensor 31 transmits photoelectricity through the filter 2, and the receiving end of the photoelectric sensor 31 converts the received photoelectric area into an electrical signal, and transmits the electrical signal to the control system, records the size of the photoelectric area, and sets it as the initial photoelectric area A; after the washing and drying machine has been running for a period of time, debris such as hair begins to accumulate on the filter 2, and at this time a part of the mesh of the filter 2 will be blocked, and the photoelectric area received by the receiving end of the photoelectric sensor 31 will be reduced, and an electrical signal will be fed back to the control system, and the control system will adjust the size of the photoelectric area according to the photoelectric area. , obtain the blockage area of ​​the filter 2, which is equal to the initial photoelectric area minus the detected photoelectric area. When the blockage area of ​​the filter 2 is greater than the first set value (which can be set to 20% A here), the control system controls the first control valve 42 to open. At this time, the spray structure 41 starts to work, and the spray port sprays the filter in all directions to clean up debris such as hair. The clogged mesh of the filter 2 will be flushed open, and the photoelectric area received by the receiving end of the photoelectric sensor 31 increases, and an electrical signal is fed back. When the blockage area of ​​the filter 2 is less than the first set value (which can be set to 5% A here), the control system controls the first control valve 42 to close and stop spraying. Afterwards, the above process will be automatically repeated according to the blockage condition of the machine filter. This can detect and clean in real time, effectively solving the problem of reduced work efficiency of existing drum washing and drying machines due to the inability to detect filter blockage and clean it in time.

[0060] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above technical content without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A control method for a washing and drying machine, characterized in that: The washer-dryer is provided with a drying air duct, wherein a filter is provided in the drying air duct to cover the air outlet of the drying air duct, and a detection device is provided on the filter to detect the blockage area of ​​the filter; the detection device is a photoelectric sensor, and the transmitting end and the receiving end of the photoelectric sensor are relatively arranged on different sides of the filter; the washer-dryer is also provided with a cleaning device for cleaning the filter in the drying air duct, the cleaning device comprising a first water pipe, a water storage tank provided in the washer-dryer, and a spray structure, the spray structure comprising a nozzle, and the nozzle having a spray port; Detecting the filter screen blockage area to obtain an actual filter screen blockage area, and comparing the actual filter screen blockage area with a first set value; When it is detected that the blockage area of ​​the filter is greater than a certain first set value, the control system controls the first control valve to open, and the first water pipe sends water in the water storage tank to the spray structure, and the spray port on the spray structure sprays the filter in all directions; When it is detected that the blockage area of ​​the filter is less than a certain second set value, the control system controls the first control valve to close, and the first water pipe stops sending the water in the water storage tank to the spray structure, and the spraying stops; The first setting value is smaller than the second setting value.

2. The control method of the washer-dryer according to claim 1, characterized in that: The photoelectric sensor comprises an infrared light emitting diode and a photosensitive transistor. The infrared light emitting diode and the photosensitive transistor are arranged on different sides of the filter. The emitting end of the infrared light emitting diode is arranged opposite to the receiving end of the photosensitive transistor.

3. The control method of the washer-dryer according to claim 1, characterized in that: The first water pipe is inserted into the drying air duct, and the water inlet of the first water pipe is connected to the water tank, and the water outlet is connected to the spray structure. The spray structure is connected in series with a first control valve, and the spray port of the spray structure faces the filter.

4. The control method of the washer-dryer according to claim 3, characterized in that: A heat exchanger is also provided in the drying air duct, and a spray structure is provided at the top of the drying air duct between the heat exchanger and the filter screen.

5. The control method of the washer-dryer according to claim 3, characterized in that: The spray structure includes a vertical pipe and an inclined pipe. The vertical pipe is arranged at the top of the drying air duct, and the water inlet of the vertical pipe is connected to the first water pipe, and its water outlet is connected to the water inlet of the inclined pipe. The water outlet of the inclined pipe is provided with a nozzle, and the nozzle has a spray port. The inclined pipe is inclined toward the filter screen.

6. The control method of a washer-dryer according to any one of claims 3 to 5, characterized in that: The washing and drying machine is provided with a water tub, a drain pipe is provided at the bottom of the water tub, and a drain valve is connected in series to the drain pipe. The cleaning device also includes a second water pipe, the water inlet of the second water pipe is connected to the drain pipe and is located upstream of the drain valve, and its water outlet is connected to the water tank, a second control valve is connected in series to the second water pipe, and a liquid level detection component for detecting the liquid level is provided in the water tank.

7. The control method for a washer-dryer according to any one of claims 1 to 5, characterized in that: The transmitting end of the photoelectric sensor transmits photoelectricity through the filter, and the receiving end of the photoelectric sensor receives the photoelectricity and obtains the photoelectric area of ​​the photoelectricity passing through the filter to obtain the actual photoelectric area. The actual photoelectric area ratio is inversely proportional to the actual filter blockage area ratio.

8. The control method of the washer-dryer according to claim 7, characterized in that: When the filter is in the initial state, the receiving end of the photoelectric sensor obtains the photoelectric area of ​​the photoelectric light passing through the filter as the original photoelectric area, the actual photoelectric area ratio is the actual photoelectric area / original photoelectric area, and the actual filter blockage area ratio is the actual filter blockage area / original photoelectric area; if the actual filter blockage area is less than the second set value, stop cleaning the filter.

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