JP7748325B2 - clothes dryer - Google Patents

Description

An embodiment of the present invention relates to a clothes dryer.

In conventional clothes dryers, to improve drying efficiency, the warm air used to remove moisture from the clothes is dehumidified and reused for drying. Dehumidification methods used in this case include air-cooled and water-cooled types. Air-cooled types use outside air taken in from outside the machine to cool and dehumidify the warm air after drying, while water-cooled types use cooling water to cool and dehumidify the warm air.

In the case of air-cooled clothes dryers, the outside air taken into the machine for cooling purposes cools the warm air after drying, raising its temperature, and then is discharged back outside. As a result, the air discharged outside raises the ambient temperature around the clothes dryer, which reduces the cooling and dehumidifying performance achieved by taking in outside air and may cause discomfort to users depending on the season. Furthermore, in the case of water-cooled clothes dryers, tap water is typically used to cool the warm air after drying. This requires the use of a large amount of tap water each time the clothes dryer is operated, making it less economical than air-cooled clothes dryers.

JP 2018-94110 A

Therefore, we provide a clothes dryer that has been improved in terms of dehumidifying warm air during drying operation.

The clothes dryer of this embodiment includes a drying chamber capable of storing clothes, a circulation air duct that returns at least a portion of the air flowing out of the drying chamber to the drying chamber, a heating device that heats the air passing through the circulation air duct, a first dehumidification mechanism that dehumidifies the air in the circulation air duct, a second dehumidification mechanism that dehumidifies the air in the circulation air duct using a method different from that used by the first dehumidification mechanism, and a control device that can drive the heating device to perform a drying operation to dry the clothes in the drying chamber. During the drying operation, the control device can perform a first dehumidification process that performs dehumidification using the first dehumidification mechanism and a second dehumidification process that performs dehumidification using the second dehumidification mechanism.

FIG. 1 is a diagram showing an example of a schematic configuration of a clothes dryer according to an embodiment, illustrating a state in which a first dehumidifying mechanism and a second dehumidifying mechanism are not operating. FIG. 1 is a diagram showing an example of a schematic configuration of a clothes dryer according to an embodiment, illustrating a state in which a first dehumidifying mechanism is operating and a second dehumidifying mechanism is not operating. FIG. 1 is a diagram illustrating an example of a schematic configuration of a clothes dryer according to an embodiment, showing a state in which a first dehumidifying mechanism is not operating and a second dehumidifying mechanism is operating. FIG. 2 is a block diagram showing an example of an electrical configuration of a clothes dryer according to one embodiment. FIG. 10 is a diagram showing, over time, input of a heating device, temperatures related to the drying operation, the rotation speed of an air blower, and the operating states of a first dehumidifying mechanism and a second dehumidifying mechanism in an example of a drying operation performed in a clothes dryer according to an embodiment. FIG. 10 is a diagram showing, over time, input power to the heating device, temperatures related to the drying operation, the rotation speed of the air blower, and the operating states of the first dehumidifying mechanism and the second dehumidifying mechanism in another example of the drying operation performed in the clothes dryer according to the embodiment.

One embodiment will be described below with reference to the drawings. The washer-dryer 10 shown in Figure 1 is an example of a clothes processing device that can perform predetermined processes on clothes, in this case at least a wash process to wash the clothes, a rinse process to rinse the clothes, and a dehydration process to spin the clothes. The washer-dryer 10 is a so-called vertical axis type washer-dryer, in which the rotation axis of the rotating tub extends vertically. The washer-dryer 10 is also an example of a clothes dryer that can perform a drying process to dry the clothes.

The clothes dryer of this embodiment can be applied to a vertical-axis washer-dryer 10, for example, as shown in Figure 1. Although not shown in detail, the clothes dryer of this embodiment can also be applied to a horizontal-axis or diagonal-axis drum washing machine, for example. The clothes dryer of this embodiment can also be applied to a clothes dryer that is dedicated to drying and does not have a washing function.

The washer-dryer 10 shown in FIG. 1 comprises an outer case 11, an outer tub 12, a rotating tub 13, a motor 14, a pulsator 15, a drainage mechanism 16, and a circulating air duct 20. Note that in FIG. 1, the side of the installation surface of the washer-dryer 10, i.e., the vertically lower side, is referred to as the lower side of the washer-dryer 10, and the side opposite the installation surface, i.e., the vertically upper side, is referred to as the upper side of the washer-dryer 10.

The outer case 11 forms the outer shell of the washer-dryer 10 and houses the outer tub 12, spinning tub 13, motor 14, pulsator 15, drainage mechanism 16, and circulating air duct 20 inside. The outer tub 12 is cylindrical and has an open top. In this embodiment, the outer tub 12 can store water inside, in which case it functions as a water tub. The outer tub 12 has a clothes opening 121 and an inner lid 122. The clothes opening 121 connects the inside and outside of the outer tub 12. The inner lid 122 opens and closes the clothes opening 121. With the inner lid 122 open, the user can load or unload clothes into the spinning tub 13 through the clothes opening 121. The washer-dryer 10 performs washing and drying operations with the inner lid 122 closed.

The outer bath 12 has a circulation outlet 123 and a circulation inlet 124. The circulation outlet 123 is provided, for example, near the bottom of the peripheral wall that forms the cylindrical portion of the outer bath 12. The circulation inlet 124 is provided, for example, on the upper side of the outer bath 12. The circulation outlet 123 and the circulation inlet 124 connect the inside and outside of the outer bath 12.

The rotatable tub 13 is formed in a cylindrical shape with a bottom that can accommodate clothes, and is rotatably housed inside the outer tub 12. The rotation axis of the rotatable tub 13 overlaps the central axis of the outer tub 12. The rotatable tub 13 has multiple communication holes 131. The communication holes 131 connect the inside and outside of the rotatable tub 13. The communication holes 131 function primarily as water holes through which water flows in and out during the washing and spin-drying operations, and as ventilation holes through which air flows in and out during the drying operation. The outer tub 12 and rotatable tub 13 function as a drying chamber in which clothes are stored and dried during the drying operation.

The motor 14 is mounted, for example, on the outside bottom of the outer tub 12. The motor 14 may be, for example, an outer rotor type direct drive motor. The motor 14 is connected to the rotating tub 13 and the pulsator 15 via a clutch mechanism (not shown). The clutch mechanism (not shown) selectively transmits the rotation of the motor 14 to the rotating tub 13 and the pulsator 15. For example, during washing, rinsing, and drying operations, the motor 14 and the clutch mechanism (not shown) transmit the driving force of the motor 14 to the pulsator 15 while the rotation of the rotating tub 13 is stopped, thereby directly driving the pulsator 15 to rotate forward and backward at a low speed. On the other hand, during spin-drying, etc., the motor 14 and the clutch mechanism (not shown) transmit the driving force of the motor 14 to the rotating tub 13, thereby driving the rotating tub 13 and the pulsator 15 to rotate at high speed in one direction.

The drain mechanism 16 has the function of draining water stored inside the outer tub 12 to the outside of the washer-dryer 10. The drain mechanism 16 is composed of a drain valve 161 and a drain pipe 162. The drain valve 161 is, for example, an electromagnetically driven liquid on-off valve. The drain pipe 162 forms a drain path from inside the outer tub 12 to the outside of the machine. The drain valve 161 is located midway along the drain path and opens and closes the drain path. The washer-dryer 10 also has a water supply mechanism, although details are not shown. The water supply mechanism, not shown, has, for example, a water supply valve 17 shown in FIG. 4 and is connected to an external water source, such as a tap, and has the function of supplying water from the external water source to the outer tub 12.

The circulation air duct 20 is provided outside the outer tub 12 and rotating tub 13, which serve as drying chambers, and is configured to circulate at least a portion of the air inside the outer tub 12 and rotating tub 13. The circulation air duct 20 connects the circulation outlet 123 and the circulation inlet 124. In this embodiment, the circulation air duct 20 is configured as a semi-open type, and opens into the outer box 11 midway along the circulation air duct 20.

That is, in this embodiment, the circulation air duct 20 is configured to include, for example, an exhaust duct 21, a heating chamber 22, and an intake duct 23. In the following description, the circulation outlet 123 of the circulation air duct 20 is defined as the most upstream side of the circulation air duct 20, and the circulation inlet 124 is defined as the most downstream side of the circulation air duct 20.

The exhaust duct 21 is provided, for example, on the outer peripheral surface of the outer tank 12 and extends vertically. The upstream side of the exhaust duct 21 is connected to the circulation outlet 123 of the outer tank 12, and the downstream side of the exhaust duct 21 is open inside the outer casing 11. The upstream side of the heating chamber 22 is open inside the outer casing 11 near the downstream side of the exhaust duct 21, and the downstream side of the heating device 33 is connected to the air supply duct 23. In other words, in this embodiment, the downstream side of the exhaust duct 21 is not physically connected to the heating chamber 22. The air supply duct 23 connects the heating chamber 22 and the outer tank 12.

The washer-dryer 10 also includes a filter device 31, an air blower 32, and a heater 33. The filter device 31, the air blower 32, and the heater 33 are provided in the circulating air duct 20. The filter device 31 is detachably provided, for example, at the downstream end of the exhaust duct 21. The filter device 31 captures dust and foreign matter contained in the air flowing through the circulating air duct 20, in this case, the air discharged from the exhaust duct 21 into the outer casing 11.

The air blower 32 is provided within the heating chamber 22 or upstream of the heating chamber 22. The air blower 32 may be configured, for example, as a sirocco fan. The air blower 32 draws a portion of the warm air discharged from the exhaust duct 21 into the heating chamber 22 along with the air surrounding the heating chamber 22, and discharges the drawn-in air toward the air intake duct 23. The heating device 33 is provided downstream of the air blower 32 within the heating chamber 22. The heating device 33 may be configured, for example, as an electric heater, and heats the air flowing through the circulating air duct 20.

In this configuration, the washer-dryer 10 performs a drying operation by driving the air blower 32 and the heating device 33. When the air blower 32 and the heating device 33 are driven, the air discharged from the air blower 32 is heated as it passes through the heating device 33, becoming warm air for drying. This air is then supplied from the circulation inlet 124 into the outer tub 12 and the rotatable tub 13. When the pressure inside the outer tub 12 increases due to the supply of warm air, some of the air inside the outer tub 12 flows out from the circulation outlet 123, passes through the exhaust duct 21, and is discharged out of the circulation air duct 20 from the downstream end of the exhaust duct 21.

A portion of the warm air discharged from the exhaust duct 21 is then sucked back into the heating chamber 22 along with the air surrounding the heating chamber 22 by the blowing action of the blower 32. The air sucked into the heating chamber 22 then passes through the heating device 33 again, becoming warm air that is then supplied into the outer tub 12. In this way, at least a portion of the air flowing out of the outer tub 12 is returned to and circulated in the outer tub 12, allowing for the drying operation to reuse the warm air generated by the heating device 33.

The washer-dryer 10 also includes a first dehumidifying mechanism 40 and a second dehumidifying mechanism 50. The first dehumidifying mechanism 40 and the second dehumidifying mechanism 50 are located midway through the air circulation duct 20 and have the function of dehumidifying the air circulating within the air circulation duct 20. The first dehumidifying mechanism 40 and the second dehumidifying mechanism 50 each use a different dehumidifying method.

The first dehumidifying mechanism 40 can be configured, for example, as a water-cooled dehumidifying mechanism. In this case, the first dehumidifying mechanism 40 has the function of supplying water into the circulation air duct 20 and using the water to cool and dehumidify the air in the circulation air duct 20. In the following description, the water discharged from the first dehumidifying mechanism 40 may be referred to as cooling water W. The cooling water W is intended to cool and dehumidify the warm air in the circulation air duct 20. The first dehumidifying mechanism 40 lowers the temperature of the air in the exhaust duct 21 and dehumidifies it by flowing the cooling water W along the inner wall of the exhaust duct 21, for example, as shown in FIG. 2. In this case, the first dehumidifying mechanism 40 can be referred to as a water-cooled dehumidifying mechanism.

The second dehumidifying mechanism 50 can be configured, for example, as an air-exchange type dehumidifying mechanism. The second dehumidifying mechanism 50 has the function of discharging a portion of the humid air in the circulation air duct 20 to the outside of the circulation air duct 20 and the outer casing 11, and of introducing outside air that is lower in humidity than the air in the circulation air duct 20 into the circulation air duct 20. In other words, the second dehumidifying mechanism 50 has the function of dehumidifying the air in the circulation air duct 20 by exchanging the high-humidity air in the circulation air duct 20 with low-humidity outside air. In this case, the second dehumidifying mechanism 50 can be referred to as an air-exchange dehumidifying mechanism. Note that this air-exchange type dehumidifying mechanism uses a different dehumidifying principle than so-called air-cooling types, which dehumidify by directly cooling the circulation air duct 20 with outside air.

When the first dehumidifying mechanism 40 is a water-cooled dehumidifying mechanism, the first dehumidifying mechanism 40 can be configured to include, for example, a water supply unit 41 and a dehumidifying valve 42. The water supply unit 41 is provided near the downstream end of the exhaust duct 21. The water supply unit 41 is connected to a water source such as a tap via the dehumidifying valve 42. The dehumidifying valve 42 can be configured as a solenoid valve for liquids.

When the dehumidification valve 42 is opened, tap water or the like is supplied from the water supply unit 41 into the exhaust duct 21 as cooling water W, as shown in FIG. 2 . The warm air that has removed moisture from the clothes in the outer tub 12 and rotating tub 13 is cooled in the exhaust duct 21 by the cooling water W supplied from the water supply unit 41, thereby dehumidifying the air. The cooling water W supplied from the water supply unit 41 into the exhaust duct 21, along with dehumidified water generated in the exhaust duct 21 by the cooling water W, is discharged outside the machine, for example, by the drainage mechanism 16.

When the second dehumidifying mechanism 50 is an air exchange type dehumidifying mechanism, the second dehumidifying mechanism 50 can be configured, for example, to include an exchange path 51, an open/close member 52, and a drive unit 53, as shown in Figures 1 and 4. The exchange path 51 is provided midway through the circulating air duct 20 and is an air path that connects the circulating air duct 20 with the outside. The exchange path 51 is configured to allow the warm air passing through the circulating air duct 20 to flow in and out, i.e., to be exchanged, with outside air, i.e., air outside the outer casing 11. The exchange path 51 can be provided upstream of the heating chamber 22, i.e., on the inlet side of the heating chamber 22. Outside air can flow into the heating chamber 22 through the exchange path 51.

The opening/closing member 52 is configured to open and close the exchange path 51 and may be configured, for example, as a damper. The drive unit 53 is, for example, an electric actuator for operating the opening/closing member 52 and may be configured, for example, as a motor or solenoid. As shown in Figures 1 and 2, when the opening/closing member 52 is closed, the exchange path 51 is closed and not connected to the outside. Therefore, there is no active exchange between the air in the circulation air path 20 and outside air, i.e., air outside the outer casing 11. In other words, when the opening/closing member 52 is closed, dehumidification by the second dehumidifying mechanism 50 is not performed. On the other hand, as shown in Figure 3, when the opening/closing member 52 is open, the exchange path 51 is open and connected to the outside. Therefore, when the opening/closing member 52 is open, there is active exchange between the air in the circulation air path 20 and outside air, i.e., air outside the outer casing 11.

The washer-dryer 10 is also equipped with multiple temperature sensors 18, 19, as shown in Figures 1 and 4. Each temperature sensor 18, 19 is capable of detecting temperatures related to the drying operation. Temperatures related to the drying operation refer to temperatures at parts of the washer-dryer 10 that change due to the drying operation. The temperatures in the outer tub 12 and the circulation air duct 20 of the washer-dryer 10 change due to the drying operation. Therefore, in this embodiment, the washer-dryer 10 is equipped with, for example, an outer tub temperature sensor 18 and an in-air duct temperature sensor 19. The outer tub temperature sensor 18 is located on the outer surface of the outer tub 12 and detects the temperature of the outer surface of the outer tub 12. The temperature of the outer surface of the outer tub 12 detected by the outer tub temperature sensor 18 correlates with the temperature inside the outer tub 12. The in-air duct temperature sensor 19 is located in the circulation air duct 20 downstream of the heating device 33 and detects the temperature of the air immediately after it is heated by the heating device 33.

As shown in FIG. 4, the washer-dryer 10 is equipped with a control device 60. The control device 60 is primarily composed of a microcomputer having a CPU 601, a storage area 602 such as ROM, RAM, and non-volatile memory, and a timer 603 capable of measuring time. The control device 60 has the function of managing the operation of the washer-dryer 10 as a whole. The motor 14, drain valve 161, water supply valve 17, temperature sensors 18 and 19, blower 32, heater 33, dehumidifier valve 42, and drive unit 53 are electrically connected to the control device 60 and operate under the control of the control device 60.

The control device 60 is capable of executing a drying operation. The drying operation is an operation in which the air blower 32 and the heater 33 are driven to supply warm air into the outer tub 12 and the rotary tub 13, which serve as the drying chamber, to dry the clothes. Furthermore, during normal drying operation, the control device 60 is capable of executing a first dehumidification process in which dehumidification is performed by the first dehumidification mechanism 40, and a second dehumidification process in which dehumidification is performed by the second dehumidification mechanism 50.

Here, "normal drying operation" refers to, for example, drying operation when there is no abnormality in the washer-dryer 10, particularly when there is no abnormality in the first dehumidification mechanism 40 or the second dehumidification mechanism 50. In this embodiment, the first dehumidification process, as shown in FIG. 2, is a process in which the dehumidification valve 42 is opened to supply cooling water W from the water supply unit 41 into the exhaust duct 21. The second dehumidification process, as shown in FIG. 3, is a process in which the opening/closing member 52 is operated to open the replacement path 51.

The control device 60 can execute a first dehumidification process and a second dehumidification process during drying operation, as shown in Figures 5 and 6, for example. Graphs (a) in Figures 5 and 6 show the transition of the input value to the heating device 33 during drying operation. Graphs (b) in Figures 5 and 6 show the transition of temperature during drying operation. In graph (b), A1 shows the temperature of the outer surface of the outer tub 12, i.e., the measurement value of the outer tub temperature sensor 18. Also, in graph (b), A2 shows the transition of the temperature immediately after the heating device 33 in the circulating air duct 20, i.e., the measurement value of the air duct temperature sensor 19.

Graphs (c) in Figures 5 and 6 show the change in the rotation speed of the blower 32 during drying operation. In this case, the rotation speed of the blower 32 correlates with the amount of air flowing through the circulating air duct 20. Graphs (d) in Figures 5 and 6 show the change in the operating status of the first dehumidifying mechanism 40 during drying operation. Graphs (e) in Figures 5 and 6 show the change in the operating status of the second dehumidifying mechanism 50 during drying operation.

The drying operation progresses in the following order: heating period T1, constant rate period T2, decreasing rate period T3, finishing period T4, and cooling period T5. The heating period T1 is the period during which the temperature of the outer tub 12 begins to increase after the drying operation is started by driving the heating device 33 and the air blower 32. The control device 60 can determine that the current period is the heating period T1, for example, when the temperature detected by the outer tub temperature sensor 18 is on an increasing trend. The control device 60 can also estimate that the current period is the heating period T1 based on the time elapsed since the drying operation started.

The constant rate period T2 is a period during which the amount of moisture evaporating from the clothes in the outer tub 12 remains constant. When the heating period T1 transitions to the constant rate period T2, the temperature of the outer tub 12 stops rising and begins to trend steadily, as indicated by arrow B1. The control device 60 can determine that the heating period T1 has transitioned to the constant rate period T2, for example, when the temperature detected by the outer tub temperature sensor 18 transitions from an increasing trend to a steady trend. The control device 60 can also infer that the heating period T1 has transitioned to the constant rate period T2 based on the time elapsed since the start of the drying operation.

Decline period T3 is a period during which the amount of moisture evaporating from the clothes in the outer tub 12 tends to decrease. When transitioning from constant rate period T2 to decline rate period T3, as shown by arrow B2, the temperature immediately after the heating device 33 drops slightly and then maintains a constant trend. For example, if the control device 60 detects a slight drop in the temperature detected by the air duct temperature sensor 19 after transitioning to constant rate period T2, it can determine that the constant rate period T2 has transitioned to decline rate period T3. The control device 60 can also infer that the constant rate period T2 has transitioned to decline rate period T3 based on the elapsed time since the start of the drying operation or the elapsed time since transitioning to constant rate period T2.

Finishing period T4 is a period in which the heating by the heater 33 and the airflow by the air blower 32 are reduced to finish the laundry. At the end of decrease rate period T3, the temperature of the outer tub 12 rises slightly, as indicated by arrow B3. After entering decrease rate period T3, the control device 60 determines that decrease rate period T3 has ended if, for example, it detects a slight increase in the temperature detected by the outer tub temperature sensor 18, and then transitions to finishing period T4. Furthermore, the control device 60 infers that decrease rate period T3 has ended if, for example, a predetermined period has passed since entering decrease rate period T3, and then transitions to finishing period T4.

The cooling period T5 is a period during which the temperature of the clothes in the outer tub 12 is lowered by stopping the heating device 33 while continuing to blow air from the air blower 32. After entering the cooling period T5, the control device 60 determines that the cooling period T5 has ended if, for example, it detects that the temperature detected by the outer tub temperature sensor 18 or the air duct temperature sensor 19 has dropped to a predetermined temperature, and stops the air blower 32 to end the drying operation. The control device 60 also infers that the cooling period T5 has ended if, for example, a predetermined period has passed since entering the cooling period T5, and stops the air blower 32 to end the drying operation.

Furthermore, as shown in Figures 5 and 6, during drying operation, the control device 60 can operate the first dehumidification mechanism 40 to perform the first dehumidification process, and then operate the second dehumidification mechanism 50 to perform the second dehumidification process. That is, the first dehumidification process is performed before the second dehumidification process. Note that in Figures 5 and 6, the period during which the first dehumidification process is performed is shown as the first dehumidification period S1, and the period during which the second dehumidification process is performed is shown as the second dehumidification period S2. The control device 60 can perform the first dehumidification process during the constant rate period T2 and the second dehumidification process during the decreasing rate period T3. Note that the control device 60 does not perform either the first or second dehumidification process during the heating period T1.

In the example of FIG. 5, the control device 60 controls the first dehumidification process and the second dehumidification process so that they do not overlap. That is, in the example of FIG. 5, the control device 60 prohibits the first dehumidification process and the second dehumidification process from being performed simultaneously, and controls the first dehumidification mechanism 40 and the second dehumidification mechanism 50 so that the first dehumidification period S1 and the second dehumidification period S2 do not overlap. In this case, the first dehumidification period S1 can be, for example, a period that coincides with the constant rate period T2. Furthermore, the second dehumidification period S2 can be, for example, a period that includes at least the decrease rate period T3. In this embodiment, the second dehumidification period S2 coincides with the combined period of the decrease rate period T3, the finishing period T4, and the cooling period T5.

In the example of FIG. 6, the control device 60 executes the first dehumidification process and the second dehumidification process during overlapping periods. That is, in the example of FIG. 6, the control device 60 can execute the first dehumidification process and the second dehumidification process simultaneously, and can control the first dehumidification mechanism 40 and the second dehumidification mechanism 50 so that the first dehumidification period S1 and the second dehumidification period S2 temporarily overlap. In the example of FIG. 6, the control device 60 executes the first dehumidification process from the constant rate period T2 to the early part of the decline rate period T3, and executes the second dehumidification process from the later part of the constant rate period T2 to the decline rate period T3. Therefore, the first dehumidification period S1 and the second dehumidification period S2 overlap in the period before and after the transition from the constant rate period T2 to the decline rate period T3.

The control device 60 can execute or terminate the first dehumidification process and the second dehumidification process based on the temperature related to the drying operation, in this case the temperature detected by the outer tub temperature sensor 18 or the air duct temperature sensor 19. In other words, the control device 60 can operate and stop the first dehumidification mechanism 40 and the second dehumidification mechanism 50 based on the temperature detected by the outer tub temperature sensor 18 or the air duct temperature sensor 19.

The control device 60 can also execute or terminate the first dehumidification process and the second dehumidification process based on the time elapsed from a reference time during the drying operation. That is, the control device 60 can operate or stop the first dehumidification mechanism 40 and the second dehumidification mechanism 50 based on the time elapsed from a reference time during the drying operation. The reference time can be set, for example, to the start of the drying operation, the transition from the first dehumidification period S1 to the second dehumidification period S2, the transition from the constant rate period T2 to the decreasing rate period T3, etc.

In the examples of Figures 5 and 6, the control device 60 can start the first dehumidification process when it detects a transition from the heating period T1 to the constant rate period T2, for example, based on the temperature detected by the outer tub temperature sensor 18. Furthermore, the control device 60 can start the first dehumidification process when a predetermined time has passed from the reference time, for example, the start of the drying operation.

In the example of Figure 5, the control device 60 can terminate the first dehumidification process and start the second dehumidification process when it detects a transition from the constant rate period T2 to the decreasing rate period T3, for example, based on the temperature detected by the air duct temperature sensor 19. Furthermore, the control device 60 can terminate the first dehumidification process and start the second dehumidification process when a predetermined time has elapsed from a reference time, for example, the start of the drying operation or the transition from the heating period T1 to the constant rate period T2.

Furthermore, in the example of FIG. 6, the control device 60 can start the second dehumidification process when a predetermined time has elapsed from the reference time, for example, the start of the drying operation or the transition from the heating period T1 to the constant rate period T2. Also, in the example of FIG. 6, the control device 60 can end the first dehumidification process when a predetermined time has elapsed from the reference time, for example, the start of the drying operation, the transition from the heating period T1 to the constant rate period T2, the start of the second dehumidification process, or the transition from the constant rate period T2 to the decreasing rate period T3. And, in the examples of FIGS. 5 and 6, the control device 60 can end the second dehumidification process upon the end of the drying operation.

According to the embodiment described above, the washer-dryer 10, which is an example of a clothes dryer, includes an outer tub 12, a rotatable tub 13, a circulation air duct 20, a heating device 33, a first dehumidifying mechanism 40, a second dehumidifying mechanism 50, and a control device 60. The outer tub 12 and the rotatable tub 13 form a drying chamber capable of accommodating clothes. The circulation air duct 20 has a function of returning at least a portion of the air flowing out of the outer tub 12 to the outer tub 12. The heating device 33 has a function of heating the air passing through the circulation air duct 20. The first dehumidifying mechanism 40 has a function of dehumidifying the air in the circulation air duct 20. The second dehumidifying mechanism 50 has a function of dehumidifying the air in the circulation air duct 20 using a method different from that of the first dehumidifying mechanism 40. The control device 60 is capable of driving the heating device 33 to perform a drying operation to dry the clothes in the outer tub 12. During drying operation, the control device 60 can perform a first dehumidification process in which dehumidification is performed by the first dehumidification mechanism 40, and a second dehumidification process in which dehumidification is performed by the second dehumidification mechanism 50.

According to this, the washer-dryer 10 is equipped with multiple (in this case, two) dehumidification mechanisms 40, 50 that employ different dehumidification methods. As a result, the control device 60 can dehumidify the air in the circulating air duct 20 during drying operation using the dehumidification mechanism 40, 50 that is appropriate for the current conditions. As a result, improvements can be made to the dehumidification of warm air during drying operation, allowing for more effective drying operation.

The dehumidification method of the first dehumidification mechanism 40 is a water-cooling method in which cooling water W is supplied into the circulation air duct 20 to cool and dehumidify the air in the circulation air duct 20. The dehumidification method of the second dehumidification mechanism 50 is an air-exchange method in which the air in the circulation air duct 20 is dehumidified by exchanging it with outside air.

Here, the first dehumidifying mechanism 40, which uses water for dehumidification and is therefore less economical than the second dehumidifying mechanism 50, which uses an air exchange system, but it has good dehumidifying efficiency and can prevent the ambient temperature of the washer-dryer 10 from rising because it does not exhaust warm air to the outside. In contrast, the second dehumidifying mechanism 50, which uses an air exchange system, exhausts a portion of the warm air in the circulating air duct 20, so although the ambient temperature of the washer-dryer 10 is more likely to rise than the first dehumidifying mechanism 40, which uses a water cooling system, it is more economical because it does not use water for dehumidification.

In this way, this embodiment can obtain the benefits of both the first dehumidifying mechanism 40 and the second dehumidifying mechanism 50, which have different characteristics, thereby achieving further improvements in dehumidifying warm air during drying operation.

Here, the constant rate period T2 is a period during which the moisture content of the clothes decreases almost linearly due to heat exchange between the thermal energy stored during the heating period T1 and the moisture contained in the clothes, and is the period during the entire drying operation when dehumidification efficiency is highest. Therefore, during the constant rate period T2, the amount of moisture contained in the warm air exhausted from the outer tub 12 is also high. Therefore, in this embodiment, the control device 60 is configured to be able to execute the first dehumidification process using the first dehumidification mechanism 40, which employs a water-cooling system, during the constant rate period T2. As a result, according to this embodiment, highly efficient dehumidification can be achieved by performing water-cooling dehumidification during the constant rate period T2, when humidity is high.

After some time has passed since the start of the first water-cooling dehumidification process, the cooling water W supplied into the circulating air duct 20 by the first dehumidifying mechanism 40 is warmed by heat exchange with the warm air in the circulating air duct 20. As the drying operation progresses and the decrease rate period T3 approaches, the temperature difference between the cooling water W and the warm air becomes smaller, and the dehumidification efficiency of the cooling water W decreases.

In this embodiment, the control device 60 can execute a second dehumidification process during the decrease rate period T3 using a dehumidification method different from that of the first dehumidification mechanism 40, in this case, the second dehumidification mechanism 50, which employs an air exchange method. This allows the second dehumidification process by the second dehumidification mechanism 50 to compensate for the decrease in dehumidification efficiency of the first dehumidification mechanism 40. As a result, this embodiment can achieve high dehumidification efficiency over a long period of drying operation, thereby improving the efficiency of drying operation.

Furthermore, in this embodiment, the warm air discharged to the outside by the second dehumidification process during the falling rate period T3 has had its humidity reduced to a certain extent by the first dehumidification process performed during the constant rate period T2 prior to the second dehumidification process. Therefore, even when the second dehumidification process is performed by air exchange, it is possible to prevent the ambient humidity around the washer-dryer 10 from increasing, making condensation more likely to occur.

As shown in FIG. 5, for example, the control device 60 controls the first dehumidification process and the second dehumidification process so that they do not overlap. This prevents the temperature in the circulating air duct 20 from dropping excessively when the first dehumidification process and the second dehumidification process are performed during overlapping periods.

Furthermore, the control device 60 can perform the first dehumidification process and the second dehumidification process during overlapping periods, as shown in FIG. 6, for example. By performing the first dehumidification process and the second dehumidification process during overlapping periods, the control device 60 can more efficiently dehumidify the warm air in the circulating air duct 20 and prevent the warm air in the circulating air duct 20 from rising excessively.

The control device 60 can also start or end the first and second dehumidification processes based on temperatures related to the drying operation, such as the temperature of the outer surface of the outer tub 12 and the temperature inside the circulating air duct 20. This allows the control device 60 to execute and end the first and second dehumidification processes at appropriate times depending on the progress of the drying operation, allowing for efficient dehumidification with minimal waste.

The control device 60 can also start or end the first dehumidification process and the second dehumidification process based on the time elapsed from the reference time during the drying operation. This allows the control device 60 to uniformly start and end the first dehumidification process and the second dehumidification process based on the time elapsed from the reference time, regardless of the progress of the drying operation, thereby simplifying the control process.

The above describes one embodiment of the present invention, but this embodiment is presented as an example and is not intended to limit the scope of the invention. This novel embodiment can be embodied in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

10... washer-dryer (clothes dryer), 12... outer tub (drying chamber), 13... rotating tub (drying chamber), 20... circulating air duct, 33... heating device, 40... dehumidifying mechanism, 40... first dehumidifying mechanism, 50... second dehumidifying mechanism, 60... control device, T2... constant rate period, T3... decreasing rate period

Claims (4)

a drying room capable of storing clothes;
a circulation air duct that connects a circulation outlet and a circulation inlet provided in the drying chamber and returns at least a portion of the air flowing out of the drying chamber to the drying chamber;
a heating device that heats the air passing through the circulating air passage;
a first dehumidifying mechanism that dehumidifies the air in the circulating air passage;
a second dehumidifying mechanism that dehumidifies the air in the circulating air passage using a method different from that of the first dehumidifying mechanism;
a control device capable of driving the heating device to perform a drying operation for drying the clothes in the drying chamber;
Equipped with
a dehumidification method of the first dehumidification mechanism is a water-cooling method in which water is supplied into the circulation air duct to cool and dehumidify the air in the circulation air duct,
a dehumidification method of the second dehumidification mechanism is an air exchange type that dehumidifies the air in the circulation air duct by exchanging the air in the circulation air duct with outside air,
when the circulation outlet is located at the most upstream side of the circulation air passage and the circulation inlet is located at the most downstream side of the circulation air passage, the second dehumidifying mechanism is provided midway along the circulation air passage and downstream of the first dehumidifying mechanism,
the second dehumidifying mechanism has an exchange path that connects the outside and the inside of the circulation air passage and discharges a portion of the warm air passing through the circulation air passage to the outside of the circulation air passage;
The control device is capable of executing a first dehumidification process for performing dehumidification using the first dehumidification mechanism and a second dehumidification process for performing dehumidification using the second dehumidification mechanism during the drying operation, and controls the first dehumidification process and the second dehumidification process so as not to be executed during overlapping periods.
Clothes dryer. the control device is capable of executing the first dehumidifying process during a constant rate period in which the amount of moisture evaporating from the clothes in the drying chamber is constant, and is capable of executing the second dehumidifying process during a decreasing rate period in which the amount of moisture evaporating from the clothes in the drying chamber tends to decrease.
The clothes dryer according to claim 1. a temperature sensor capable of detecting a temperature of a portion that changes due to the influence of the drying operation as a temperature related to the drying operation;
The control device is capable of starting or ending the first dehumidification process and the second dehumidification process based on a temperature related to the drying operation.
The clothes dryer according to claim 1 or 2 . Further provided with a timer capable of measuring time,
The control device is capable of starting or ending the first dehumidification process and the second dehumidification process based on an elapsed time from a preset reference time during the drying operation.
The clothes dryer according to claim 1 or 2 .