JP2021045330A - Clothes dryer - Google Patents

Abstract

To prevent frost formation/freezing of an evaporator effectively, and to maintain favorable drying performance.SOLUTION: A clothes dryer includes: an opening part for exhaust provided between an exhaust port and a heat pump duct out of a circulation air passage, and for exhausting air in the circulation air passage to the outside; an exhaust damper for opening/closing the opening part for exhaust; an outside air inlet provided being positioned between an evaporator and a condenser of the heat pump duct; a room temperature sensor for detecting an atmospheric temperature of the outside of a heat pump; an evaporator temperature sensor for detecting a temperature of an inlet part of the evaporator; and a control device for executing a drying operation by controlling each mechanism. The control device executes an evaporator frost formation prevention operation for bringing the exhaust damper into an open state, in the case where the detection temperature of the room temperature sensor is a low temperature which is equal to or lower than a first predetermined temperature at the start time of the drying operation.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a clothes dryer.

Conventionally, as a clothes dryer, a drum-type clothes dryer that employs a heat pump is known (see, for example, Patent Document 1). This drum-type clothes dryer is provided with an air supply port and an exhaust port in a water tank having a large number of holes and rotatably provided with a drum for accommodating clothes, and the air supply port and the exhaust port are provided outside the water tank. A circulating air passage to be connected is provided together with a fan device for blowing air, and an evaporator and a condenser of a heat pump are arranged in the circulating air passage so as to supply dry air into the water tank.

As a result, the moist air discharged from the drum is dehumidified by passing through the evaporator, and subsequently heated by passing through the condenser so that it becomes hot dry air and is supplied to the drum again. It has become. Compared to the heater method, this heat pump method dries at a lower temperature, so that the clothes are less damaged by heat, and power consumption and time can be shortened. In recent years, a multi-flow type heat exchanger having a higher heat exchange efficiency than a conventional fin tube type has been adopted for the condenser and the evaporator.

Japanese Patent No. 5979434

By the way, in this kind of clothes dryer, for example, when the drying operation is started in an environment of low room temperature, the temperature of the refrigerant in the evaporator may drop too much, and frost may occur in the evaporator. Then, the fin portion of the evaporator freezes, which causes a problem that a part of the ventilation path is blocked to reduce the heat exchange efficiency. In Patent Document 1, when frost is formed on the evaporator, the frost is melted by controlling the compressor. However, since the countermeasure is taken after the frost is generated, the drying time is long. turn into.
Therefore, a clothes dryer capable of effectively preventing frost formation and freezing of the evaporator and maintaining good drying performance is provided.

In the clothes dryer of the embodiment, the outside of the drum is between a drum provided in the main body and accommodating clothes, an exhaust port for discharging air from the drum, and an air supply port for blowing air into the drum. A circulation air passage provided in the above, a blower for circulating the air in the drum through the circulation air passage, a heat pump duct forming a part of the circulation air passage, a compressor, and the heat pump duct. To discharge the air in the circulation air passage to the outside, which is provided between the exhaust port and the heat pump duct in the circulation air passage and the heat pump including the evaporator and the condenser arranged inside. The exhaust opening, the exhaust damper that opens and closes the exhaust opening, the outside air suction port provided between the evaporator and the condenser of the heat pump duct, and the ambient temperature outside the heat pump. A room temperature sensor for detecting the above, an evaporator temperature sensor for detecting the temperature at the inlet of the evaporator, and a control device for controlling each mechanism to execute the drying operation, and the control device is for drying operation. At the start, when the detection temperature of the room temperature sensor is a low temperature equal to or lower than the first predetermined temperature, the evaporator frost formation prevention operation for opening the exhaust damper is executed.

The right side view of the vertical section which shows the 1st Embodiment and shows roughly the internal structure of a washer-dryer. Longitudinal rear view schematically showing the internal configuration of the washer / dryer including the heat pump External perspective view of the washer / dryer seen from the back side Perspective view of the vicinity of the lint filter showing a part of the top plate of the outer box broken. Block diagram schematically showing the electrical configuration of the washer / dryer Flow chart showing the control procedure at the start of the drying operation executed by the control device The figure which shows the state of the change of the condenser temperature, the inlet temperature and the outlet temperature of an evaporator with the lapse of time at the start of a drying operation when the room temperature is 20 ° C. The figure which shows the state of the change of the condenser temperature, the inlet temperature and the outlet temperature of the evaporator with the lapse of time at the start of the drying operation when the room temperature is 5 ° C. and the evaporator frost prevention operation is not executed. The figure which shows the state of the change of the inlet temperature and the outlet temperature of the evaporator with the lapse of time at the start of the drying operation when the evaporator frosting prevention operation is executed at a room temperature of 5 ° C. A flowchart showing the second embodiment and showing the control procedure at the start of the drying operation executed by the control device. A flowchart showing a third embodiment and showing a control procedure at the start of the drying operation executed by the control device.

Hereinafter, some embodiments applied to a drum-type washer-dryer equipped with a heat pump and having both a washing function and a drying function will be described with reference to the drawings. In the plurality of embodiments described below, the common parts will be designated by the same reference numerals, and new illustrations and repetitive explanations will be omitted.

(1) First Embodiment The first embodiment will be described with reference to FIGS. 1 to 9. First, with reference to FIGS. 1 to 5, the overall configuration of the washer / dryer 1 as the clothes dryer according to the present embodiment will be described. As shown in FIG. 1 and the like, the outer box 2 constituting the main body of the washer / dryer 1 has a substantially rectangular box shape, and the cylindrical water tank 3 is inclined backward in the outer box 2. It is supported via an elastic support mechanism (not shown). In the water tank 3, a cylindrical rotating drum 4 (hereinafter, simply referred to as “drum 4”) as a drum for accommodating clothes to be laundry is rotatably supported. The drum 4 is configured to rotate about an inclined axis extending in the front-rear direction and inclined slightly backward from the horizontal.

As shown in FIG. 1, a large number of holes 4a for water passage and ventilation are formed in the peripheral wall portion and the rear wall portion of the drum 4, and the inner surface of the peripheral wall portion of the drum 4 is used for washing laundry. A plurality of baffles (not shown) are provided. Although not shown in detail, the front portion of the drum 4 is provided with a circular opening through which clothes are taken in and out, and the front portion of the water tank 3 is formed with an inlet 3a connected to the opening. ing. A door 5 for opening and closing the insertion port 3a is provided on the front surface of the outer box 2. An operation panel 6 is provided on the upper portion of the front surface of the outer box 2. Although not shown in detail, the operation panel 6 is provided with a display unit and an operation unit.

As shown in FIGS. 1 and 2, a drum motor 8 made of, for example, an outer rotor type brushless motor constituting a drive mechanism is arranged at the rear portion of the water tank 3. As shown in FIG. 1, the tip of the rotating shaft of the drum motor 8 penetrates the back surface of the water tank 3 and protrudes into the water tank 3, and is connected and fixed to the rear central portion of the drum 4. With such a configuration, the drum 4 is directly rotationally driven by the drum motor 8. In this case, the drum 4 is continuously rotated in the normal rotation direction, that is, in the clockwise direction when viewed from the front in the dehydration stroke. In the washing stroke, rinsing stroke, drying stroke, etc., the drum 4 is repeatedly rotated forward and backward.

Although not shown in detail, a water supply mechanism for supplying water from tap water as a water supply source to the inside of the water tank 3 or the like is provided in the upper part of the outer box 2. This water supply mechanism includes a water supply valve 7 (shown only in FIG. 5). On the other hand, as shown in FIG. 1, a drainage pipe line 12 is connected to the lower part of the water tank 3, and a drainage valve 13 is provided in the middle of the drainage pipe line 12. When water is supplied into the water tank 3 by the water supply mechanism with the drain valve 13 closed, the water is stored in the water tank 3. At this time, the water level in the water tank 3 is detected by a water level sensor (not shown). As the drain valve 13 is opened, the water stored in the water tank 3 is discharged to the outside of the machine through the drain pipe line 12. Further, in the outer box 2, a room temperature sensor 14 is provided near the drainage pipe line 12. The room temperature sensor 14 is composed of, for example, a thermistor, and detects the room temperature, which is the ambient temperature outside the heat pump 15 inside the outer box 2.

As shown in FIG. 1, the water tank 3 is provided with an exhaust port 17 for discharging the air in the drum 4 at the upper right side portion of the front portion, and in the drum 4 at the upper left side portion of the back portion. An air supply port 18 for supplying dry air is provided. Then, as shown in FIGS. 1 and 2, inside the outer box 2, a warm air supply mechanism 19 for circulating and supplying dry air, that is, warm air to the inside of the drum 4 to execute the drying operation of clothes is provided. ing.

The hot air supply mechanism 19 is located outside the water tank 3 and includes a circulation air passage 20. The inlet of the circulation air passage 20 is connected to the exhaust port 17 of the water tank 3, and the outlet of the circulation air passage 20 is connected to the air supply port 18. The hot air supply mechanism 19 includes a heat pump 15 that dehumidifies and heats the circulating air to generate dry air. At the same time, the blower fan 16 as a blower device that supplies the air discharged from the exhaust port 17 from the air supply port 18 into the water tank 3 and the drum 4 while circulating in the circulation air passage 20 in the direction of arrow A is provided. I have.

Specifically, as shown in FIGS. 1 and 2, the circulation air passage 20 includes an upper exhaust duct 21, a rear exhaust duct 22, a heat pump duct 24, and an air supply duct 25. The exhaust duct is composed of the upper exhaust duct 21 and the rear exhaust duct 22. As shown in FIG. 1, the upper exhaust duct 21 is provided with its base end connected to the exhaust port 17 and extending the upper right side in the outer box 2 rearward, and the rear exhaust duct 21 is provided at the tip thereof. The upper end of 22 is connected. A well-known lint filter 26 for capturing lint from dry air is provided in the middle of the upper exhaust duct 21 so that it can be taken in and out of the outer box 2. As shown in FIGS. 3 and 4, the lint filter 26 is provided with a lid plate 26a having a handle portion 26b on the upper surface thereof, and the lid plate 26a is arranged so as to face the upper surface of the outer box 2.

Further, as shown in FIG. 4, the upper part of the middle part of the upper exhaust duct 21 is located behind the lint filter 26 and is for exhaust for exhausting the internal air from the upper surface of the outer box 2. An opening 9 is provided. As shown in FIG. 3, the exhaust opening 9 is connected to the outer box exhaust port 2a provided on the upper surface of the outer box 2. Then, as shown in FIG. 1, an exhaust damper 10 for opening and closing the exhaust opening 9 is provided. The exhaust damper 10 is opened and closed by a drive mechanism including a damper motor 11 (shown only in FIG. 5) and the like. With this, by opening the exhaust damper 10, a part of the air flowing in the circulation air passage 20 can be discharged to the outside of the outer box 2 from the exhaust opening 9 through the outer box exhaust port 2a.

As shown in FIG. 2, the rear exhaust duct 22 has a rectangular cross section, extends downward behind the water tank 3, and its lower end is connected to the right end, which is the base end of the heat pump duct 24. There is. The heat pump duct 24 has a rectangular cross section, and extends in the right-left direction from the bottom rear portion in the outer box 2. At this time, as shown in FIG. 2, in the heat pump duct 24, the evaporator 27 and the condenser 28 constituting the heat pump 15 are arranged in order on the left and right (left and right in FIG. 2). An outside air suction port 23 for taking in outside air is provided on the upper wall of the heat pump duct 24, located between the evaporator 27 and the condenser 28.

As shown in FIG. 2, the blower fan 16 is provided on the tip end side (right end side in FIG. 2) of the heat pump duct 24. The blower fan 16 is configured to include, for example, a centrifugal fan 33 and a fan motor 34 for driving the centrifugal fan 33 in a fan casing 32. The lower end portion, which is the base end portion of the air supply duct 25, is connected to the outlet portion of the fan casing 32. The air supply duct 25 extends upward behind the water tank 3 on the left side in the outer box 2, and the upper end portion, which is the tip end portion thereof, is connected to the air supply port 18.

The heat pump 15 is configured by connecting a compressor 29, a condenser 28, a throttle valve 30 as a depressurizing means, and an evaporator 27 in a closed loop shape by a refrigerant pipe 31. A required amount of refrigerant is sealed inside the heat pump 15 and circulates in the refrigerant pipe 31. At this time, the condenser 28 functions as a heating means for heating the dry air, and the evaporator 27 functions as a dehumidifying means for removing moisture from the dry air. In the present embodiment, the evaporator 27 and the condenser 28 are composed of a so-called multi-flow type heat exchanger, and as a whole, are configured in a rectangular block shape slightly thin in the air flow direction. As is well known, in a multi-flow type heat exchanger, flat plates having a plurality of refrigerant flow holes inside and heat exchange fins are alternately laminated, and one end side of the plurality of flat plates is placed on an inlet side header portion. The other end side of the plurality of flat plates is connected by the outlet side header portion.

In this heat pump 15, as shown by the arrow B in the flow of the refrigerant in FIG. 2, the gaseous refrigerant discharged from the compressor 29 by driving the compressor 29 flows into the condenser 28, and the condenser 28 It is condensed by heat exchange in the above to make a liquid refrigerant. The liquid refrigerant flowing out of the condenser 28 is expanded by the throttle valve 30 to form a mist, and the mist-like refrigerant flows into the evaporator 27. Then, in the evaporator 27, the refrigerant is vaporized by heat exchange with the outside air, and the gaseous refrigerant is returned to the compressor 29. Further, a circulation is performed in which the refrigerant is compressed by the compressor 29 and discharged at a high temperature and a high pressure.

By driving the blower fan 16 together with the drive of the heat pump 15, the air in the water tank 3, that is, the drum 4, is moved from the exhaust port 17 to the upper part as shown by the arrow A in FIGS. 1 and 2. It passes through the exhaust duct 21 and the rear exhaust duct 22 in order to reach the heat pump duct 24. At this time, when the air passes through the upper exhaust duct 21, the lint, that is, lint contained in the air is captured by the lint filter 26 and the like.

Then, the air that has passed through the rear exhaust duct 22 flows through the heat pump duct 24, passes through the evaporator 27 and the condenser 28 in order, then flows into the air supply duct 25, passes through the air supply port 18 and the hole 4a, and is a drum. A cycle of being supplied within 4 is performed. This air circulation removes moisture from the clothes in the water tank 3, that is, the drum 4, and the air containing a large amount of steam is cooled through the evaporator 27 portion in the heat pump duct 24, so that the steam is condensed or It is sublimated and dehumidified, and the dehumidified air is heated by passing through the condenser 28 portion to become dry warm air, which is supplied into the drum 4 again and is used for drying clothes.

Further, as shown in FIG. 2, a plurality of temperature sensors including, for example, a thermistor for detecting the temperature of the refrigerant are provided in the main part of the heat pump 15. That is, a discharge temperature sensor 35 is provided near the discharge port of the compressor 29. A condenser temperature sensor 36 is provided in the condenser 28 portion. An evaporator temperature sensor 37 is provided in the evaporator 27 portion. An inlet temperature sensor 38 is provided near the inlet of the compressor 29.

Further, as shown in FIG. 1, the circulation air passage 20 is also provided with a plurality of temperature sensors for dry air, for example, made of a thermistor, for detecting the temperature of the dry air. Specifically, an air supply port temperature sensor 39 is provided in the vicinity of the air supply port 18, and an exhaust temperature sensor 40 is provided in the rear exhaust duct 22 portion. Then, as shown in FIG. 1, in the outer box 2, for example, a control device 41 mainly composed of a microcomputer and controlling the entire washer / dryer 1 is provided.

FIG. 5 schematically shows the electrical configuration of the washer / dryer 1 centered on the control device 41. That is, an operation signal from the operation unit of the operation panel 6 is input to the control device 41, and the control device 41 controls the display of the display unit of the operation panel 6. Further, the control device 41 includes detection signals from the room temperature sensor 14, discharge temperature sensor 35, condenser temperature sensor 36, evaporator temperature sensor 37, inlet temperature sensor 38, air supply port temperature sensor 39, and exhaust temperature sensor 40. Is entered.

The control device 41 controls the water supply valve 7, the drain valve 13, the drum motor 8, the fan motor 34 of the blower fan 16, the compressor 29 and the throttle valve 30 of the heat pump 15, the damper motor 11, and the like. With the above configuration, the control device 41 is the mechanism of the washing / drying machine 1 based on the input signal from each sensor and the control program stored in advance according to the operation course set by the user on the operation panel 6. A well-known washing operation consisting of a washing process, a rinsing process, and a dehydration process, and a drying operation are automatically executed. At this time, when executing the drying operation, the control device 41 drives and controls the compressor 29 of the heat pump 15, the blower fan 16, and the like based on the detection temperatures of the room temperature sensor 14 and each of the temperature sensors 35 to 40. The drum 4 is rotationally driven. During normal drying operation, the exhaust damper 10 is closed.

By the way, in the present embodiment, as described in the following description of operation (explanation of the flowchart), the control device 41 is at a low temperature where the room temperature tr detected by the room temperature sensor 14 is equal to or lower than the first predetermined temperature at the start of the drying operation. In a certain case, the evaporator frost formation prevention operation for opening the exhaust damper 10 is executed. More specifically, the first predetermined temperature is 5 ° C. However, when the detected room temperature tr is below the freezing point of 0 ° C. or lower, the drying operation and the washing operation itself are not performed. Further, in the present embodiment, this evaporator frost formation prevention operation is executed with respect to T0 for a certain period of time from the start of the drying operation. The fixed time T0 is set to any time in the range of 10 minutes to 25 minutes, for example, 20 minutes.

Next, the operation of the washer / dryer 1 having the above configuration will be described with reference to FIGS. 6 to 9. The flowchart of FIG. 6 shows a processing procedure mainly related to an evaporator frost formation prevention operation executed by the control device 41 during the drying operation. That is, in step S1, when the drying operation is started, the compressor 29 of the heat pump 15, the blower fan 16, and the drum 4 are driven. In step S2, the room temperature tr detected by the room temperature sensor 14 is read. In step S3, it is determined whether or not the detected room temperature tr is a first predetermined temperature, in this case, a low temperature of 5 ° C. or lower. As described above, it is assumed that the detected room temperature tr is higher than 0 ° C.

If the room temperature tr detected by the room temperature sensor 14 exceeds 5 ° C. (No in step S3), the process proceeds to step S7, and normal drying operation control is performed. On the other hand, when the room temperature tr detected by the room temperature sensor 14 is a low temperature of 5 ° C. or lower (Yes in step S3), the process proceeds to step S4, and the evaporator frost formation prevention operation is executed. Here, when the room temperature tr is as low as 5 ° C. or less, if the drying operation is continued as it is, the temperature of the refrigerant flowing through the evaporator 27 drops excessively to below the freezing point, and frost formation on the surface of the evaporator 27 occurs. There was a risk of it occurring. However, in the present embodiment, the exhaust damper 10 is opened by the control of the damper motor 11 in the evaporator frost formation prevention operation in step S4.

By executing this evaporator frost prevention operation, as shown in FIG. 1, a part of the air flowing in the direction of arrow A in the circulation air passage 20 passes the lint filter 26 in the middle of the upper exhaust duct 21 and is partially indicated by an arrow. As shown by C, the air is discharged from the exhaust opening 9. As the air is discharged from the exhaust opening 9, as shown by an arrow D in FIG. 2, the outside air, that is, the air in the outer box 2 is introduced into the heat pump duct 24 from the outside air suction port 23 provided in the heat pump duct 24. Inhaled. Even if the temperature of the evaporator 27 portion is low, for example, 0 ° C. or lower, the outside air sucked from the outside air suction port 23 has a positive temperature, which is higher than the temperature of the evaporator 27. Further, since the outside air suction port 23 is located between the evaporator 27 and the condenser 28, the low temperature air that has passed through the evaporator 27 mixes with the outside air and the temperature rises to raise the condenser 28. The temperature of the circulated air gradually rises as it passes through.

By opening the exhaust damper 10 in this way, the cold air circulating in the circulation air passage 20 is replaced with the air having a higher temperature, and the evaporator 27 remains at a low temperature or is at a lower temperature. This can be prevented and the temperature can be raised. As a result, the temperature of the evaporator 27 can be rapidly raised from the state of 0 ° C. or lower, and even if moist air passes through the evaporator 27, frost formation and freezing are prevented.

Returning to FIG. 6, in step S5, it is determined whether or not a predetermined time T0 (for example, 20 minutes) has elapsed from the start of the evaporator frost formation prevention operation. If the predetermined time T0 has not elapsed (No in step S5), the evaporator frost prevention operation in step S4 is continued. When the predetermined time T0 has elapsed (Yes in step S5), the evaporator frost formation prevention operation is completed and the exhaust damper 10 is returned to the closed state in step S6. After that, in step S7, normal drying operation control is performed.

Here, FIGS. 7 to 9 show changes in the temperature of the condenser 28, the inlet temperature and the outlet temperature of the evaporator 27 with the passage of time in the initial stage of the start of the drying operation, and FIG. 7 shows the room temperature. For example, in the case of 20 ° C., FIG. 8 shows a case where the evaporator frost prevention operation is not executed at a room temperature of, for example, 5 ° C., and FIG. ing. In FIG. 9, the condenser temperature is omitted, and the temperature change between the evaporator 27 and the condenser 28 is added.

Now, as shown in FIG. 7, for example, even when the room temperature is relatively high, when the drying operation is started and the compressor 29 or the like is driven, the temperature of the refrigerant inside the heat pump 15 is increased by heat exchange in the condenser 28. The temperature drops sharply, and the inlet temperature of the evaporator 27 further drops from 0 ° C. to reach, for example, about −20 ° C. However, since the temperature of the condenser 28 rises sharply due to the action of the compressor 29, the temperature of the evaporator 27 also rises after a few minutes, and returns to 0 ° C. or higher after a dozen minutes, for example. In this case, even if the inlet temperature of the evaporator 27 is as low as 0 ° C. or less in the initial stage of drying in which the temperature of the clothes in the drum 4 is in the process of rising and the evaporation of water from the clothes has not yet occurred. No frost or freezing occurs. Then, after a certain period of time T0 (for example, 10 to 25 minutes) has elapsed from the start of drying, the inlet temperature of the evaporator 27 also becomes a positive temperature exceeding 0 ° C. Therefore, frost formation and freezing of the evaporator 27 also occur. do not do.

On the other hand, as shown in FIG. 8, when the room temperature at the start of the drying operation is as low as 5 ° C., the temperature of the air flowing through the circulation air passage 20 does not rise easily at the initial stage of drying, and the condenser 28 does not rise. It will not be sufficiently heated and the temperature of the evaporator 27 will not rise. Therefore, even if T0 elapses for a certain period of time from the start of drying, the inlet temperature of the evaporator 27 remains 0 ° C. or lower and does not rise to the positive temperature, and when moist air passes through the evaporator 27, the evaporator Frost may occur on the surface of 27, causing freezing.

However, in the present embodiment, even when the room temperature at the start of the drying operation is as low as 5 ° C., the evaporator frost formation prevention operation is executed from the start of drying as described above, and the exhaust damper 10 is opened. .. As a result, as shown in FIG. 9, the inlet temperature of the evaporator 27 can be raised to a positive temperature by T0 for a certain period of time. As a result, frost formation and freezing in the evaporator 27 can be prevented. If the room temperature tr is relatively high at the start of the drying operation and exceeds 5 ° C., the evaporator frost formation prevention operation is not executed, and the drying operation under normal control can be promptly proceeded.

As described above, according to the washer / dryer 1 of the present embodiment, the following effects can be obtained. That is, in the present embodiment, the control device 41 opens the exhaust damper 10 when the room temperature tr detected by the room temperature sensor 14 is a low temperature of 5 ° C. or lower, which is the first predetermined temperature, at the start of the drying operation. The evaporator is configured to perform the frost formation prevention operation. As a result, the temperature of the evaporator 27 can be raised relatively early, and frost formation and freezing of the evaporator 27 can be prevented. In this case, since the evaporator 27 is prevented from frosting by controlling at the start of the drying operation instead of taking measures after the frost formation occurs, it is possible to take measures to prevent frosting at an early stage. Therefore, according to the present embodiment, it is possible to obtain an excellent effect that frost formation can be effectively prevented while suppressing an unnecessarily long drying time.

Further, in the present embodiment, the evaporator frost formation prevention operation is executed for a certain period of time from the start of the drying operation with respect to T0. In this case, if the evaporator frost prevention operation is executed longer than necessary, the drying efficiency is lowered and the drying time is lengthened. Therefore, the evaporator frost prevention operation is completed at T0 for a certain period of time. It is desirable to do so, and frost formation can be effectively prevented. Further, in the present embodiment, the first predetermined temperature is set to 5 ° C. As described in the explanation of FIG. 7, it has been clarified that, in reality, if the room temperature tr exceeds 5 ° C., there is almost no risk of frost formation or freezing even if normal drying operation is performed. Therefore, it is desirable to carry out the evaporator frost formation prevention operation with the temperature of 5 ° C. or lower as a guide.

(2) Second, Third Embodiment, Other Embodiments The flowchart of FIG. 10 shows the second embodiment, and mainly prevents frost formation on the evaporator, which is executed by the control device 41 during the drying operation. The processing procedure related to the operation is shown. The difference between this second embodiment and the flowchart of FIG. 6 of the first embodiment is that the control device 41 detects the evaporator temperature sensor 37 when the evaporator frost formation prevention operation is executed for a certain period of time. When the temperature te is a second predetermined temperature, for example, a low temperature of 0 ° C. or lower, the evaporator frost formation prevention operation is continuously executed.

That is, in the flowchart of FIG. 10, the drying operation is started in step S1, and the room temperature tr detected by the room temperature sensor 14 is read in step S2. In step S3, it is determined whether or not the detected room temperature tr is a first predetermined temperature, which is a low temperature of 5 ° C. or lower, and when the room temperature tr detected by the room temperature sensor 14 is a low temperature of 5 ° C. or lower (step). Yes) in S3, and the evaporator frost prevention operation is executed in step S4. Then, in step S5, when it is determined that a predetermined time T0 (for example, 20 minutes) has elapsed from the start of the evaporator frost prevention operation (Yes in step S5), in step S11, the evaporator temperature sensor 37 The detected temperature te at the inlet of the evaporator 27 is read.

In the next step S12, it is determined whether or not the detected temperature te is equal to or less than the second predetermined temperature, in this case 0 ° C. or less. If the detection temperature te of the evaporator temperature sensor 37 is 0 ° C. or lower (Yes in step S12), the process proceeds to step S13, and the evaporator frost prevention operation is continuously executed. After that, the process from step S11 is repeated again. On the other hand, if the detection temperature te of the evaporator temperature sensor 37 exceeds the second predetermined temperature of 0 ° C. in this case (No in step S12), the evaporator frost formation prevention operation is completed in step S6. Then, in step S7, normal drying operation control is performed.

According to this second embodiment, as in the first embodiment, the execution of the evaporator frost formation prevention operation effectively prevents frost formation while suppressing the drying time from becoming unnecessarily long. You can get the excellent effect of being able to do it. Then, for example, especially when the room temperature tr is low, it is expected that the frost formation prevention operation is not sufficient for T0 for a certain period of time. If the detection temperature te of the evaporator temperature sensor 37 is lower than the second predetermined temperature even after the elapse of T0 for a certain period of time, the evaporator frost formation prevention operation is continuously executed, so that the evaporator 27 is frosted and frozen. Can be prevented more reliably.

The flowchart of FIG. 11 shows a third embodiment, and also shows a processing procedure executed by the control device 41 during the drying operation. In the third embodiment, the control device 41 determines that the detection temperature te of the evaporator temperature sensor 37 is a second predetermined temperature, for example, a high temperature exceeding 0 ° C. during the execution of the evaporator frost formation prevention operation. , The evaporator frost formation prevention operation is terminated without waiting for the elapse of T0 for a certain period of time.

That is, in the flowchart of FIG. 11, the drying operation is started in step S1, and the room temperature tr detected by the room temperature sensor 14 is read in step S2. In step S3, it is determined whether or not the detected room temperature tr is a first predetermined temperature, which is a low temperature of 5 ° C. or lower, and when the room temperature tr detected by the room temperature sensor 14 is a low temperature of 5 ° C. or lower (step). Yes) in S3, and the evaporator frost prevention operation is executed in step S4. Then, in the next step S21, the temperature te of the inlet portion of the evaporator 27 detected by the evaporator temperature sensor 37 is read.

In the next step S22, it is determined whether or not the detection temperature te of the evaporator temperature sensor 37 is equal to or lower than the second predetermined temperature and in this case is larger than 0 ° C. When the detection temperature te is 0 ° C. or lower (No in step S22), the process returns to step S4, and the evaporator frost formation prevention operation is continuously executed. On the other hand, when the detection temperature te of the evaporator temperature sensor 37 exceeds the second predetermined temperature of 0 ° C. in this case (Yes in step S22), the evaporator frost formation prevention operation is performed in step S6. After completion, in step S7, normal drying operation control is performed.

According to the third embodiment, as in the first embodiment, the execution of the evaporator frost prevention operation effectively prevents frost formation while suppressing the drying time from becoming unnecessarily long. You can get the excellent effect of being able to do it. Then, when the temperature te of the inlet of the evaporator 27 detected by the evaporator temperature sensor 37 is low, there is a risk of frost formation, but when the temperature of the refrigerant flowing into the evaporator 27 becomes high, that There is no fear. Therefore, by monitoring the temperature at the inlet of the evaporator 27 with the evaporator temperature sensor 37, the evaporator frost formation prevention operation can be promptly terminated when the second predetermined temperature is exceeded, which is wasteful. It is possible to proceed to normal drying operation control without.

It should be noted that the specific numerical values such as the first predetermined temperature, the second predetermined temperature, and the fixed time disclosed in each of the above embodiments are merely examples, and can be appropriately changed and implemented. .. Further, in the above embodiment, a so-called multi-flow type evaporator and condenser are adopted, but a so-called fin tube type heat exchanger may be adopted. In addition, it can be applied to a clothes dryer dedicated to drying without a washing function. The overall configuration of the heat pump For example, the configuration of the circulation air passage may be such that the heat pump duct is arranged in the upper part of the outer box.

The above embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The present embodiment and its modifications are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

In the drawing, 1 is a washer / dryer (clothes dryer), 2 is an outer box (main body), 4 is a drum, 9 is an exhaust opening, 10 is an exhaust damper, 11 is a damper motor, 14 is a room temperature sensor, and 15 is a heat pump. , 16 is a blower fan (blower), 17 is an exhaust port, 18 is an air supply port, 20 is a circulation air passage, 23 is an outside air intake port, 24 is a heat pump duct, 25 is an air supply duct, 27 is an evaporator, 28. Is a condenser, 29 is a compressor, 37 is an evaporator temperature sensor, and 41 is a control device.

Claims (5)

A drum that is installed inside the main body and stores clothes,
A circulation air passage provided so as to communicate between an exhaust port for discharging air from the drum and an air supply port for blowing air into the drum on the outside of the drum.
A blower that circulates the air in the drum through the circulation air passage, and
The heat pump duct that forms part of the circulation air passage and
A heat pump including a compressor and an evaporator and a condenser arranged in the heat pump duct, and a heat pump.
Of the circulation air passage, an exhaust opening provided between the exhaust port and the heat pump duct for discharging the air in the circulation air passage to the outside, and an exhaust opening.
An exhaust damper that opens and closes the exhaust opening,
An outside air intake port provided between the evaporator and the condenser of the heat pump duct,
A room temperature sensor that detects the ambient temperature outside the heat pump,
An evaporator temperature sensor that detects the temperature at the inlet of the evaporator and
A control device that controls each of the above mechanisms to execute a drying operation is provided.
At the start of the drying operation, the control device performs an evaporator frost prevention operation for opening the exhaust damper when the detection temperature of the room temperature sensor is a low temperature equal to or lower than the first predetermined temperature. Machine. The clothes dryer according to claim 1, wherein the control device executes an evaporator frost formation prevention operation for a certain period of time from the start of the drying operation. The clothes dryer according to claim 1 or 2, wherein the control device executes the evaporator frost formation prevention operation when the detection temperature of the room temperature sensor is 5 ° C. or lower at the start of the drying operation. The control device continues the evaporator frost prevention operation when the detection temperature of the evaporator temperature sensor is a low temperature equal to or lower than the second predetermined temperature when the evaporator frost prevention operation is executed for a certain period of time. The clothes dryer according to any one of claims 1 to 3. The control device terminates the evaporator frost prevention operation when the detection temperature of the evaporator temperature sensor is a high temperature exceeding a second predetermined temperature during the execution of the evaporator frost prevention operation. The clothes dryer according to any one of 4 to 4.

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