Drum-type washer-dryer

Abstract

To provide a drum type washing and drying machine capable of suppressing drying unevenness in clothing which is hard to dry, without significantly extending time.SOLUTION: A drum type washing and drying machine 10 comprises a heat pump unit 15 in an air circulation path 20 for circulating air in a drum 12, and the machine 10 can execute clothing determination processing (S3) of determining whether laundry is "easy to dry clothing" or "hard to dry clothing", during a drying operation which is performed by driving the heat pump unit 15. When the laundry is determined to be "easy to dry clothing" in the clothing determination processing (NO in S4), an intake air temperature to the drum 12 is maintained to be a first intake air temperature by the drive of the heat pump unit 15 (S8). When the laundry is determined to be "hard to dry clothing" in the clothing determination processing (YES in S4), the intake air temperature to the drum 12 is increased to a second intake air temperature (S6) by the drive of the heat pump unit 15.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a drum type washer / dryer equipped with a heat pump and a heater. [Background technology]

[0002] Patent Document 1 discloses a drum-type washer-dryer using a heat pump dehumidification system that includes a heater in addition to a heat pump. The heater is energized for a predetermined time at the beginning of the drying operation to accelerate the temperature rise of the warm air, reduce power consumption, and improve the drying speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-143735 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional drum-type washer-dryers described above, when the laundry is thick or other clothes that are difficult to dry, the operation may end before the laundry is completely dry (for example, before all the moisture inside the clothes, such as the pockets or hood, has been removed), resulting in uneven drying.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a drum-type washer-dryer that can prevent uneven drying of clothes that are difficult to dry without significantly extending the drying time. [Means for solving the problem]

[0006] In order to solve the above problems, the drum type washer-dryer of the present invention is a drum type washer-dryer equipped with a heat pump in an air circulation path for circulating air inside the drum, and during drying operation performed by driving the heat pump, a clothing determination process can be performed to determine whether the laundry is "easy-to-dry clothes" or "hard-to-dry clothes." If the clothing determination process determines that the laundry is "easy-to-dry clothes," the heat pump is driven to maintain the intake air temperature to the drum at a first intake air temperature, and if the clothing determination process determines that the laundry is "hard-to-dry clothes," the heat pump is driven to perform intake temperature increase control to increase the intake air temperature to the drum to a second intake air temperature higher than the first intake air temperature.

[0007] According to the above configuration, a clothing determination process is performed during the drying operation, and if this clothing determination process determines that the laundry is "hard-to-dry clothing," intake air temperature increase control can be additionally performed. By additionally performing this intake air temperature increase control, uneven drying of "hard-to-dry clothing" can be suppressed without significantly extending the drying time. Furthermore, for "hard-to-dry clothing," normal control, which does not perform intake air temperature increase control, can be used to avoid an increase in power consumption.

[0008] The drum type washer-dryer may further include a heater in the air circulation path, and during the intake air temperature increase control, the heater may be activated until the intake air temperature into the drum reaches the second intake air temperature.

[0009] In addition, in the above-mentioned drum type washer-dryer, the clothing determination process makes a determination based on the exhaust temperature and exhaust humidity from the drum, and can be configured to determine that the clothing is ``difficult to dry'' when both a temperature condition where the exhaust temperature is below a first temperature threshold and a humidity condition where the exhaust humidity is above a first humidity threshold are met, and to determine that the clothing is ``easy to dry'' when at least one of the temperature condition and the humidity condition is not met.

[0010] Furthermore, the drum type washer-dryer can be configured to sense the laundry volume before starting the washing / drying operation, and if the laundry volume is equal to or greater than a predetermined value, to perform the clothing determination process and the intake air temperature increase control when the laundry is determined to be "hard-to-dry clothes," and not to perform the clothing determination process or the intake air temperature increase control when the laundry volume is less than the predetermined value.

[0011] According to the above configuration, when the laundry volume is small and uneven drying of the laundry is unlikely to occur, an increase in power consumption due to switching of control can be avoided. [Effects of the Invention]

[0012] The drum-type washer-dryer of the present invention has the effect of suppressing uneven drying of "hard-to-dry clothes" without significantly extending the drying time by additionally performing intake air temperature increase control when the laundry is determined to be "hard-to-dry clothes." [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating a general configuration of a drum-type washer-dryer according to an embodiment of the present invention. [Figure 2] 4 is a flowchart showing drying operation control in the washer / dryer. [Figure 3] 10 is a sub-flowchart showing a clothing determination process. [Figure 4] 10 is a timing chart showing ON / OFF of a heat pump unit and an assist heater when intake air temperature increase control is performed during drying operation control. [Figure 5] 10 is a timing chart showing ON / OFF of the heat pump unit and the assist heater when intake air temperature increase control is not performed during drying operation control. [Figure 6] 10 is a graph showing an example of changes in exhaust temperature and intake temperature when intake temperature increase control is performed; [Figure 7]10 is a graph showing an example of changes in exhaust temperature and intake temperature when intake temperature increase control is not performed. DETAILED DESCRIPTION OF THE INVENTION

[0014] First Embodiment DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present invention will be described in detail below with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram showing the general configuration of a drum-type washer-dryer 10 according to the present embodiment (hereinafter simply referred to as a washer-dryer);

[0015] Washer / dryer 10 includes water tub 11 and drum 12, which is rotatably disposed within water tub 11 and contains laundry. Water tub 11 and drum 12 each open toward door 13, and laundry can be placed in or removed from drum 12 by opening door 13. The peripheral wall of drum 12 is formed with a plurality of through-holes (not shown) that allow liquid and gas to flow between the space between water tub 11 and drum 12 and the space within drum 12. In addition, the bottom of drum 12 is formed with a plurality of air inlet holes (not shown) that communicate with air intake port 111 of water tub 11.

[0016] Washer / dryer 10 also includes air circulation path 20 for circulating air within drum 12. Air circulation path 20 has first air circulation duct 21, second air circulation duct 22, and third air circulation duct 23, and guides air that has left drum 12 and exited water tub 11 during drying operation so that the air returns to drum 12.

[0017] One end of first air circulation duct 21 is connected to exhaust port 112 of water tub 11, and the other end is connected to the intake side of filter device housing 14. This filter device housing 14 is disposed at the rear of the upper space of washer-dryer 10, and detachably houses filter device 141.

[0018] One end of the second air circulation duct 22 is connected to the exhaust side of the filter device housing 14, and the other end is connected to the intake side of a heat pump unit (heat pump) 15. The inside of the heat pump unit 15 communicates with the inside of the blower fan unit 16. The heat pump unit 15 is disposed at the rear of the lower space of the washer-dryer 10, and generates dry, high-temperature air.

[0019] One end of third air circulation duct 23 is connected to the outlet (exhaust side) of blower fan unit 16, and the other end is connected to intake port 111 of water tank 11. In addition, blower fan unit 16 is disposed downstream of heat pump unit 15.

[0020] The heat pump unit 15 has a refrigerant circuit formed by an evaporator 151, a compressor (not shown), a condenser 152, and an expansion mechanism (not shown) connected in a ring shape inside a casing. In the heat pump unit 15, the evaporator 151 and the condenser 152 are arranged on the air circulation path 20, with the evaporator 151 located upstream of the condenser 152. The evaporator 151 performs heat exchange to lower the temperature of the air that flows into the heat pump unit 15. The heat exchange in the evaporator 151 condenses and removes moisture in the air. The condenser 152 performs heat exchange to raise the temperature of the air that has passed through the evaporator 151. The heat exchange in the condenser 152 generates dry, high-temperature air.

[0021] In washer-dryer 10, air inside drum 12 is circulated through air circulation path 20 by driving blower fan unit 16. That is, blower fan unit 16 sends dry, high-temperature air from heat pump unit 15 to third air circulation duct 23. This high-temperature air is introduced into drum 12 through air intake 111.

[0022] The high-temperature air introduced into drum 12 removes moisture from the laundry contained in drum 12, becoming moist, low-temperature air. This low-temperature air flows from exhaust port 112 of water tub 11 through first air circulation duct 21, filter device housing 14, and second air circulation duct 22 in this order, and is then introduced into heat pump unit 15. At this time, filter device 141 captures lint and other particles contained in the low-temperature air.

[0023] The washer-dryer 10 mainly dries laundry using the heat pump unit 15, but also includes an assist heater (heater) 17 as an auxiliary heat source during drying operation. The assist heater 17 is disposed between the condenser 152 and the blower fan unit 16, and can further heat the air that is heated by the condenser 152 and flows toward the blower fan unit 16. For example, a PTC (Positive Temperature Coefficient) heater can be used as the assist heater 17. Note that while FIG. 1 illustrates a configuration in which the assist heater 17 is disposed inside the casing of the heat pump unit 15, the assist heater 17 may also be disposed outside the casing of the heat pump unit 15.

[0024] The washer-dryer 10 according to this embodiment is characterized by its drying operation control, which determines how easily the laundry will dry and controls the temperature of intake air into the drum 12 based on the determination. To perform this drying operation control, the washer-dryer 10 is equipped with an exhaust air temperature and humidity sensor 18 that measures the temperature and humidity of the exhaust air (humid low-temperature air) from the drum 12, and an intake air temperature sensor 19 that measures the temperature of the intake air (dry high-temperature air) into the drum 12. The exhaust air temperature and humidity sensor 18 is equipped with both a temperature sensor and a humidity sensor.

[0025] The exhaust air temperature and humidity sensor 18 is provided on the air circulation path 20 upstream of the heat pump unit 15, and in the example of Fig. 1 is located near the exhaust port of the filter device housing 14. The intake air temperature sensor 19 is provided on the air circulation path 20 downstream of the heat pump unit 15 and the assist heater 17, and in the example of Fig. 1 is located near the exhaust port of the blower fan unit 16. The washer-dryer 10 also has a control unit 30 that controls the heat pump unit 15 and the assist heater 17 based on the detection data of the exhaust air temperature and humidity sensor 18 and the intake air temperature sensor 19.

[0026] FIG. 2 is a flowchart showing the drying operation control (hereinafter referred to as the present control) in the washer / dryer 10. FIG. 3 is a sub-flowchart showing the clothing determination process performed during the drying operation control. FIG. 4 is a timing chart showing the ON / OFF of the heat pump unit 15 and the assist heater 17 when the intake air temperature increase control is performed during the drying operation control. FIG. 5 is a timing chart showing the ON / OFF of the heat pump unit 15 and the assist heater 17 when the intake air temperature increase control is not performed during the drying operation control. FIG. 6 is a graph showing an example of changes in the exhaust air temperature and the intake air temperature when the intake air temperature increase control is performed. FIG. 7 is a graph showing an example of changes in the exhaust air temperature and the intake air temperature when the intake air temperature increase control is performed.

[0027] The drying operation of the washer-dryer 10 is initiated by activating the drum 12, the heat pump unit 15, and the blower fan unit 16 (at timing T11 or T21). In this control, the assist heater 17 is also activated at the start of the drying operation and continues to be activated until the intake air temperature (measured by the intake air temperature sensor 19) reaches a predetermined first intake air temperature (e.g., 50°C) (at timing T12 or T22) (S1). Because the heat pump unit 15 has a slow temperature rise, using the assist heater 17 in the initial stage of the drying operation can reduce power consumption and improve the drying speed. When the intake air temperature reaches the predetermined first intake air temperature, the assist heater 17 is stopped, and the first intake air temperature is then maintained by controlling the heat pump unit 15 (specifically, by controlling the compressor speed in the heat pump unit 15) (S2).

[0028] Furthermore, a clothing determination process is performed (S3) after a predetermined time has elapsed since the assist heater 17 was stopped (at timing T13 or timing T23). This clothing determination process determines how easily the laundry dries, i.e., whether the laundry is "hard-to-dry clothing" or "easy-to-dry clothing." The predetermined time is set to a time sufficient for the intake air temperature to stabilize after the assist heater 17 is stopped and the intake air temperature drops. In other words, at the time the clothing determination process is performed, the air flowing through the air circulation path 20 is not affected by the assist heater 17.

[0029] In this clothing determination process, the ease of drying of laundry is determined based on the exhaust temperature and exhaust humidity detected by the exhaust temperature and humidity sensor 18. Specifically, as shown in FIG. 3, the exhaust temperature is compared with a first temperature threshold value (e.g., 40°C) (S31), and the exhaust humidity is compared with a first humidity threshold value (e.g., absolute humidity 30 g / m 3) (S32). If the exhaust temperature is low (the exhaust temperature is equal to or lower than the first temperature threshold) and the exhaust humidity is high (the exhaust humidity is equal to or higher than the first humidity threshold) (YES in S31 and S32), the laundry is determined to be "hard-to-dry clothes" (S33). On the other hand, in other cases (NO in at least one of S31 and S32), the laundry is determined to be "easy-to-dry clothes" (S34).

[0030] The determination based on exhaust temperature may be made based on the gradient of the exhaust temperature at the time of performing the clothing determination process, instead of comparing the exhaust temperature itself with a threshold value as described above. Specifically, if the gradient of the exhaust temperature at time T13 or time T23 is equal to or less than a first temperature gradient threshold (e.g., +0.5°C / min), the exhaust temperature can be determined to be low. Determination based on the gradient of the exhaust temperature is less affected by the outside air temperature, but the process is somewhat complicated. Therefore, determination based on the exhaust temperature itself or determination based on the gradient of the exhaust temperature may be used interchangeably depending on the specifications and environment.

[0031] Here, "hard-to-dry clothes" are considered to be laundry that initially contains a large amount of moisture, and that still evaporates a large amount of moisture from the laundry even after a predetermined time has passed since the start of the drying operation. If a large amount of moisture evaporates, the heat of the high-temperature air that is taken in is used to evaporate the moisture, lowering the exhaust temperature and increasing the exhaust humidity. Therefore, if the exhaust temperature is equal to or lower than the first temperature threshold and the exhaust humidity is equal to or higher than the first humidity threshold, the laundry can be determined to be "hard-to-dry clothes."

[0032] On the other hand, "easy-drying clothes" are laundry that initially contains a small amount of moisture, and it is thought that the moisture evaporating from the laundry decreases to a certain extent after a certain time has passed since the start of the drying operation. If the amount of moisture evaporating is small, the heat of the high-temperature air taken in is not consumed, and the exhaust temperature increases. Therefore, if the exhaust temperature exceeds the first temperature threshold, the laundry can be determined to be "easy-drying clothes." Note that if the amount of moisture contained in the clothes before the drying operation is extremely low, such as when the clothes are dry or when additional drying is being performed after drying indoors, the heat pump unit 15 may not be able to maintain the first intake air temperature. For this reason, even if the exhaust temperature is below the first temperature, the laundry is determined to be "easy-drying clothes" if the exhaust humidity is below the first humidity threshold.

[0033] Note that the humidity used in the above clothing determination process is absolute humidity, but if the humidity measured by the exhaust temperature and humidity sensor 18 is relative humidity, the absolute humidity can be detected (calculated) from the temperature and humidity measured by the exhaust temperature and humidity sensor 18.

[0034] If the laundry is determined to be "hard-to-dry clothes" by the clothing determination process (YES in S4), intake air temperature increase control is performed. In this intake air temperature increase control, the heat pump unit 15 is controlled so that the intake air temperature becomes the second intake air temperature. The assist heater 17 is also restarted and continues to be activated until the intake air temperature reaches a predetermined second intake air temperature (e.g., 55°C) (until timing T14) (S5). The second intake air temperature is set to a temperature higher than the first intake air temperature. When the intake air temperature reaches the second intake air temperature, the assist heater 17 is stopped, and thereafter the second intake air temperature is maintained by controlling the heat pump unit 15 (S6).

[0035] While the pump unit 15 continues to operate while maintaining the second intake air temperature, the control unit 30 monitors the degree of dryness of the laundry based on the exhaust air temperature and exhaust air humidity. If it determines that the laundry is dry (dry determination) (S7, timing T15), the control unit 30 performs the finishing step (S10) and ends the drying operation (timing T16). The laundry is determined to be dry when, for example, the exhaust air temperature is equal to or higher than the second temperature threshold and the exhaust air humidity is equal to or lower than the second humidity threshold. The second temperature threshold is a temperature higher than the first temperature threshold, and the second humidity threshold is a humidity lower than the first humidity threshold. In addition, in the finishing step, the assist heater 17 is restarted and the intake air temperature is temporarily increased in order to raise the surface temperature of the laundry.

[0036] If the laundry is determined to be "easy-to-dry clothes" by the clothing determination process (NO in S4), normal control is performed without performing intake air temperature increase control. That is, the assist heater 17 is not restarted, and the first intake air temperature is maintained by controlling the heat pump unit 15 (S8). Then, if it is determined that the laundry is dry (dry determination) (S9, timing T24), the finishing process (S10) is performed and the drying operation is terminated (timing T25). Note that the laundry is determined to be dry during normal control when, for example, the exhaust air temperature is equal to or higher than the third temperature threshold and the exhaust air humidity is equal to or lower than the third humidity threshold. The third temperature threshold is set to a temperature higher than the first temperature threshold and lower than the second temperature threshold. This is because the intake air temperature at the time of dryness determination differs between intake air temperature increase control and normal control. The third humidity threshold may be the same humidity as the second humidity threshold.

[0037] As described above, the washer-dryer 10 according to this embodiment performs a clothing determination process during the drying operation, and if the clothing determination process determines that the laundry is "hard-to-dry clothes," it additionally performs intake air temperature increase control. Recent washer-dryer machines sense the laundry volume before starting the washing and drying operation to predict the washing and drying time. However, if the laundry is "hard-to-dry clothes," uneven drying may occur, or attempts to prevent uneven drying may result in a significant extension of the drying time. In response to this, the washer-dryer 10 can prevent uneven drying even for "hard-to-dry clothes" without significantly extending the drying time by additionally performing intake air temperature increase control. Furthermore, for "easy-to-dry clothes," normal control, which does not perform intake air temperature increase control, can be used to avoid increased power consumption.

[0038] Second Embodiment When the laundry is "hard-to-dry clothes," uneven drying is more likely to occur when the laundry volume is large, but less likely to occur when the laundry volume is small. For this reason, the above-mentioned clothing determination process and intake air temperature increase control may be switched between being performed or not performed depending on the laundry volume. That is, in capacity sensing before the start of the washing / drying operation, if the laundry volume is equal to or greater than a predetermined value, the clothing determination process and intake air temperature increase control may be performed, and if the laundry volume is less than the predetermined value, the clothing determination process and intake air temperature increase control may not be performed. This makes it possible to avoid an increase in power consumption due to control switching when the laundry volume is less than the predetermined value.

[0039] Furthermore, the predetermined time from when the assist heater 17 stops until the clothing determination process is performed may be changed depending on the laundry volume. When the laundry volume is large, it takes time for heat to be applied to the entire laundry, which tends to delay the rise in exhaust temperature. By extending the predetermined time until the clothing determination process is performed, the determination can be performed after heat has been applied to the entire laundry, improving the accuracy of the determination in the clothing determination process.

[0040] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention should not be interpreted solely by the above-described embodiments, but should be defined by the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0041] 10 Drum type washer-dryer 11 Aquarium 111 Air intake 112 Exhaust port 12 drums 13 Door 14 Filter device storage section 141 Filtering device 15 Heat pump unit (heat pump) 151 Evaporator 152 Condenser 16 Blower fan unit 17 Assist heater (heater) 18 Exhaust temperature and humidity sensor 19 Intake air temperature sensor 20 Air circulation path 21 First air circulation duct 22 Second air circulation duct 23 Third air circulation duct

Claims

1. A drum-type washer-dryer having a heat pump in an air circulation path for circulating air in the drum, During the drying operation performed by driving the heat pump, a clothing determination process can be performed to determine whether the laundry is "easy-to-dry clothing" or "hard-to-dry clothing." When the clothing determination process determines that the clothing is "easy-to-dry clothing," the heat pump is driven to maintain the intake air temperature to the drum at a first intake air temperature; When the clothing determination process determines that the clothing is "hard-to-dry clothing," an intake air temperature increase control is performed to increase the intake air temperature to the drum to a second intake air temperature higher than the first intake air temperature by driving the heat pump. The clothing determination process is performed based on the temperature and humidity of the exhaust air from the drum at a predetermined timing after the start of the drying operation, When both a temperature condition in which the exhaust temperature is equal to or lower than a first temperature threshold and a humidity condition in which the exhaust humidity is equal to or higher than a first humidity threshold are satisfied, the clothing is determined to be "hard-to-dry clothing," If at least one of the temperature condition and the humidity condition is not met, the clothing is determined to be "easy-drying clothing," A heater is provided in the air circulation path, The heater is activated from the start of the drying operation until the intake air temperature reaches a predetermined value, The drum type washer-dryer is characterized in that the predetermined timing is set after a predetermined time has elapsed since activation of the heater at the start of a drying operation is stopped.

2. The drum type washer-dryer according to claim 1, In the intake air temperature increase control, the heater is activated until the intake air temperature into the drum reaches the second intake air temperature.

3. The drum type washer-dryer according to claim 1 or 2, Before starting the washing and drying operation, the laundry volume is sensed. If the laundry volume is equal to or greater than a predetermined value, the clothing determination process is performed, and if the laundry is determined to be "hard-to-dry clothes" by the clothing determination process, the intake air temperature increase control is performed. A drum-type washer-dryer characterized in that, if the laundry capacity is less than a predetermined value, the clothing determination process and the intake air temperature increase control are not performed, and the intake air temperature to the drum is maintained at a first intake air temperature by driving the heat pump.

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