JP7833441B2 - Clothes dryer - Google Patents

Description

Embodiments of this invention relate to a clothes dryer.

In clothes dryers equipped with heat pumps, the use of flammable refrigerants with low ozone depletion potential and low global warming potential is being considered due to growing environmental concerns.

Because the amount of refrigerant sealed in the heat pump of a clothes dryer is small, even if refrigerant leaks from the heat pump, the concentration inside the clothes dryer's casing is unlikely to reach the ignition limit, making a fire highly improbable. However, various safety measures have been proposed in the event of a refrigerant leak (see, for example, Patent Document 1 below).

In Patent Document 1 below, the compressor and throttle of a heat pump, as well as the connecting pipes that connect them to the evaporator and condenser, are covered with a cover. When a refrigerant detector installed inside the cover detects a leak of flammable refrigerant, the compressor is stopped and an exhaust fan is activated to discharge the leaked refrigerant to the outside.

However, in Patent Document 1 below, if flammable refrigerant leaks from the heat pump, it accumulates inside the cover. Therefore, if the refrigerant detector malfunctions or has errors, it may not be able to accurately detect the concentration of flammable refrigerant inside the cover, potentially reaching the ignition limit concentration.

Japanese Patent Publication No. 2009-207673

The embodiments of this invention have been made in consideration of the above circumstances, and aim to provide a highly safe clothes dryer equipped with a heat pump using a flammable refrigerant, which can suppress ignition even if the flammable refrigerant leaks out.

A clothes dryer according to one embodiment comprises a drying chamber for storing clothes, a circulating air passage with both ends connected to the drying chamber, a blower for circulating air between the drying chamber and the circulating air passage, a condenser for heating the air in the circulating air passage, an evaporator for cooling and dehumidifying the air in the circulating air passage, a compressor for compressing a flammable refrigerant and supplying it to the condenser, a heat pump connected by a refrigerant transport pipe to a depressurizing means for depressurizing the flammable refrigerant that has passed through the condenser, and a housing for housing the drying chamber, the circulating air passage, the blower, and the heat pump, wherein the housing has an opening that connects the inside and outside of the housing. A clothes dryer having an opening, wherein the condenser and the evaporator each comprise a refrigerant pipe through which a flammable refrigerant flows and fins attached to the refrigerant pipe, the refrigerant pipe comprising a plurality of straight sections to which the fins are attached, a first folded section provided to connect one end of the plurality of straight sections, a joint section joining one end of the plurality of straight sections and the first folded section, and a second folded section folded back at the other end of the plurality of straight sections and integrally provided with the plurality of straight sections , wherein the plurality of straight sections and the second folded section are located inside the circulating air passage, and the joint section is located outside the circulating air passage.

Front view of a clothes dryer according to one embodiment, with the door removed. Figure 1 is a longitudinal cross-sectional side view showing the schematic configuration of a clothes dryer. Cross-sectional view along line A-A in Figure 1 Rear view showing the exterior of the clothes dryer (Figure 1) Figure 3, section view along line B-B Cross-sectional view of the heat exchange section installed in the modified clothes dryer.

The following description of one embodiment of the present invention will be made with reference to the drawings. Note that the following embodiments are illustrative and the scope of the invention is not limited thereto. Various omissions, substitutions, and modifications can be made to the following embodiments without departing from the spirit of the invention. The following embodiments and their variations are included within the scope of the invention and its equivalents as described in the claims.

In the following explanation, left-right, front-back, and up-down directions refer to the directions when viewing the washer-dryer from the front. The left-right direction corresponds to the width of the washer-dryer. Furthermore, unless otherwise specified, right, left, up, down, front, and back refer to the position or side of the washer-dryer when viewed from the front.

This embodiment relates to a drum-type washer-dryer that combines the functions of a washing machine and a clothes dryer. As shown in Figures 1 and 2, the housing 1 consists of a roughly rectangular box-shaped outer casing 1a and a base plate 1b provided at its lower part.

The front of the outer box 1a has a laundry entrance/exit 3, which is an opening located approximately in the center. The laundry entrance/exit 3 is opened and closed by a door 4 that is rotatable laterally via a hinge (see Figure 2).

Inside the enclosure 1, as shown in Figure 2, there is a water tank 8, a circulating air passage 20 connected to the water tank 8, a blower 27 for circulating air between the water tank 8 and the circulating air passage 20, a heat pump 35 for dehumidifying and heating the air in the circulating air passage 20, and, as shown in Figure 3, a ventilation path 50 is provided outside the circulating air passage 20.

The water tank 8 is approximately cylindrical in shape, with an open front and a closed rear, and the front opening communicates with the laundry entrance/exit 3. The water tank 8 is elastically supported on the base plate 1b via an elastic support mechanism, with its axial direction oriented in the front-to-back direction. Water, such as tap water, is supplied from outside the machine through a water inlet located at the top of the water tank 8 via a water supply valve, and the water in the water tank 8 can be drained outside the machine through a drain valve at a drain outlet (not shown) located at the bottom of the water tank 8.

A cylindrical rotating drum 14, with an open front and a closed rear, is rotatably mounted inside the water tank 8. The rotating drum 14 is positioned within the water tank 8 with its axial direction in the front-to-back direction. Numerous holes 15 are formed in the peripheral wall of the rotating drum 14, allowing for water and air passage. These holes 15 connect the inside of the rotating drum 14 to the water tank 8.

The front opening of the rotating drum 14 is also connected to the laundry inlet/outlet 3, and the rotating drum 14 accommodates the laundry that is put in from the laundry inlet/outlet 3. The rotating drum 14 is driven to rotate by a drum motor 17 located on the back of the water tank 8. The rotating drum 14, with this configuration, functions as a washing tank during the washing process, a spin-drying tank during the spin-drying process, and a drying tank during the drying operation.
It functions as a drying room.

As shown in Figure 2, the water tank 8 has an exhaust port 10 located at the lower front end of the water tank 8 and an air intake port 11 located slightly above the center of the rear surface of the water tank 8. A circulating air passage 20 is connected to both the exhaust port 10 and the air intake port 11.

As shown in Figures 2 to 4, the circulating air passage 20 comprises, in order from upstream to downstream in the air circulation direction, an exhaust duct 22, a heat exchange unit 30, and an air supply duct 26. Air from the water tank 8 is exhausted through the exhaust duct 22 connected to the exhaust port 10, and air flowing through the circulating air passage 20 is supplied to the water tank 8 through the air supply duct 26 connected to the air supply port 11.

The exhaust duct 22 extends downward from the lower front end of the water tank 8, starting from the exhaust port 10, and its tip (lower end) is connected to an opening 42a provided on the upper surface of the heat exchange section 30.

The heat exchange unit 30 comprises a housing 40 placed on a base plate 1b below the water tank 8, an evaporator 31 provided inside the housing, and a condenser 32 positioned within the housing 40, spaced downstream from the evaporator 31 in the air circulation direction.

As shown in Figures 3 and 5, the evaporator 31 and condenser 32 provided in the heat exchange section 30 are both fin-tube type heat exchangers, each comprising a refrigerant pipe and fins 31b and 32b attached to the refrigerant pipe.

The refrigerant pipe is made of a material with high thermal conductivity, such as copper, and is formed in a meandering shape, comprising multiple straight sections 31a1, 32a1, first folded sections 31a2, 32a2 that are folded back in a U-shape to connect one end of the straight sections 31a1, 32a1, joint sections 31a3, 32a3 that are joined to one end of the straight sections 31a1, 32a1 and the first folded sections 31a2, 32a2 by brazing, and second folded sections 31a4, 32a4 that are folded back in a U-shape at the other end of the straight sections 31a1, 32a1 and integrally provided with the straight sections 31a1, 32a1.

The fins 31b and 32b are attached in a predetermined arrangement at a specific pitch to the straight sections 31a1 and 32a1 of the refrigerant pipe.

The inlet 32a5 of the refrigerant pipe of the condenser 32 is joined to the outlet of the refrigerant transport pipe 36, which is connected to the discharge side of the compressor 33, by inserting and fitting the pipes with different diameters, and then brazing the ends that are exposed to the outside. The outlet 32a6 of the refrigerant pipe of the condenser 32 is joined to one end of the refrigerant transport pipe 37 by brazing in the same manner.

The refrigerant transport pipe 37 connects the condenser 32 and the evaporator 31. It includes a capillary tube and an adjustable solenoid valve, and is equipped with a pressure reducing section 34 to reduce the pressure of the refrigerant that has passed through the condenser 32.

The other end of the refrigerant transport pipe 37 is joined to the inlet 31a5 of the refrigerant pipe of the evaporator 31 by brazing, in the same manner as described above. Furthermore, the outlet 31a6 of the refrigerant pipe of the evaporator 31 is joined to the refrigerant transport pipe 38, which is connected to the suction side of the compressor 33, also by brazing, in the same manner as described above.

As described above, the evaporator 31 and condenser 32 are connected to the compressor 33 and pressure reducing unit 34 in a ring-like configuration via refrigerant transport pipes 36, 37, and 38, thereby constituting the heat pump 35.

The housing 40 comprises a lower member 41 that opens upward, a lid 42 that closes the upper opening of the lower member 41, and a sealing member 43 that seals the space between the lower member 41 and the lid 42.

The lower member 41 is a flattened, container-shaped member with a space formed inside for housing the evaporator 31 and condenser 32. The lower member 41 separates the airflow path through which air circulates within the circulating air passage 20 from the lid 42, and also receives the dehumidified water generated in the evaporator 31. The bottom surface 41a of the lower member 41 is gently sloped downwards toward the rear, guiding the dehumidified water generated in the evaporator 31 to the drainage means 44 provided on the rear surface 1c of the outer casing 1a for drainage.

Such a housing 40 is placed on the base plate 1b, positioned to one side (for example, the left side) of the space formed between the water tank 8 and the base plate 1b. An opening 42a for connecting the lower end of the exhaust duct 22 is provided at the front end of the lid 42, and an air supply duct 26 is connected to the rear end of the lower member 41, allowing air to flow through the housing 40 towards the rear.

The compressor 33, although not shown in detail, comprises a compression mechanism and a motor. The motor is supplied with a drive power supply at a set frequency via an inverter power supply. As a result, the motor rotates at a speed corresponding to the supplied frequency, driving the compressor 33 at the desired set output.

The compressor 33 and the pressure reducing unit 34 are positioned away from the heat exchange unit 30 in a direction perpendicular to the direction of airflow within the heat exchange unit 30. In other words, the compressor 33 and the pressure reducing unit 34 are located in the space formed between the water tank 8 and the base plate 1b, on the side (right side) of the heat exchange unit 30.

The heat pump 35 is filled with a hydrocarbon-based flammable refrigerant such as isobutane (hereinafter sometimes referred to as the refrigerant). The compressor 33 circulates the refrigerant, causing the evaporator 31 to cool and dehumidify the air flowing inside the housing 40, and the condenser 32 to heat the air dehumidified by the evaporator 31.

A sirocco fan 27a is provided at the connection point between the heat exchange unit 30 and the air supply duct 26, located downstream of the heat exchange unit 30 in the air circulation direction, and connected to the air supply port 11 of the water tank 8.

The sirocco fan 27a, together with the fan motor 27b located in the space between the water tank 8 and the base plate 1b, constitutes the blower 27. The fan motor 27b is positioned on the rear side (rear right) of the heat exchange unit 30, with its rotating shaft 27c extending backward. The rotating shaft 27c of the fan motor 27b penetrates the back surface 1c of the outer casing 1a, and the sirocco fan 27a is attached to its tip. When the sirocco fan 27a rotates, powered by the fan motor 27b, it draws in the dehumidified and heated air from the heat exchange unit 30 and discharges it into the air supply duct 26.

As shown in Figures 3 and 4, the air supply duct 26 consists of a vertically extending flow path formed between the duct cover 28 attached to the back surface 1c of the outer casing 1a and the back surface 1c of the outer casing 1a. Air discharged from the sirocco fan 27a flows upward through the air supply duct 26 and is supplied to the water tank 8 and then to the rotating drum 14 through the inlet 29 provided on the back surface 1c of the outer casing 1a.

The ventilation path 50 is a space formed outside the water tank 8 and the circulating air passage 20 inside the housing 1, and is a space independent of the circulating air passage 20, with air flow between it and the circulating air passage 20 substantially blocked.

The ventilation path 50 houses the compressor 33 and pressure reducing unit 34 that constitute the heat pump 35, as well as the fan motor 27b of the blower 27. The ventilation path 50 also includes a first opening 51 located to the side (right) of the heat exchange unit 30 where the compressor 33 and fan motor 27b are located, penetrating the base plate 1b vertically, and a second opening 52 (see Figure 4) located above the first opening 51 on the rear surface 1c of the outer casing 1a. The ventilation path 50 communicates with the external space of the housing 1 through the first opening 51 and the second opening 52.

In this ventilation path 50, when the heat pump 35 and blower 27 are operating, the heat generated from the compressor 33 and fan motor 27b creates an upward airflow. Air from outside the housing 1 is drawn in through the first opening 51 and discharged outside the housing 1 through the second opening 52, thus circulating within the ventilation path 50.

In Figure 3, reference numeral 53 denotes a capacitor for motor drive located in the ventilation path 50, which supplies power to the drum motor 17 that rotates the rotating drum 14. The capacitor 53 is housed in an explosion-proof case with its connection terminals (i.e., the charged portion) facing downwards, and is fixed to the base plate 1b on the side of the heat exchange section 30. Between the connection terminals (the charged portion) of the capacitor 53, which is an electrical component located on the base plate 1b, and the joint portions 31a3 and 32a3 of the evaporator 31 and condenser 32, a partition 54 is provided, rising upward from the base plate 1b. The partition 54 protrudes above the capacitor 53, separating the capacitor 53 from the joint portions 31a3 and 32a3.

In the washing and drying machine with the above configuration, the evaporator 31 and condenser 32 are arranged such that the first folded portions 31a2, 31a2 and the joint portions 31a3, 31a3 are located in the ventilation path 50, and the straight portions 31a1, 32a1, the second folded portions 31a4, 32a4 and the fins 31b, 32b are located within the heat exchange section 30 that constitutes the circulating air passage 20.

Specifically, within the housing 40, which is partitioned by the lower member 41 and the lid 42, the straight sections 31a1, 32a1, the second folded sections 31a4, 32a4, and the fins 31b, 32b of the evaporator 31 and condenser 32 are housed, while the first folded sections 31a2, 32a2 and the joint sections 31a3, 32a3 are housed in the water receiving section 45, which is provided adjacent to the outside of the housing 40.

As shown in Figure 5, the water receiving section 45 has a container-like shape, comprising a bottom surface 45a provided below the first folded sections 31a2, 32a2 and the joint sections 31a3, 32a3, and a peripheral wall 45b rising upward from its periphery, with an opening 45c formed at the top.

The water receiving section 45 is positioned between the compressor 33 and the depressurization section 34 and the heat exchange section 30. It is located adjacent to one side of the heat exchange section 30 where the compressor 33 and depressurization section 34 are located, and is separated from the interior of the housing 40 by a partition wall 46 extending parallel to the air circulation direction within the housing 40.

The partition wall 46 separating the water receiving section 45 and the housing 40 has one end of each straight section 31a1 and 32a1 that penetrates it in an airtight manner, while the first folded sections 31a2 and 32a2 and the joint sections 31a3 and 32a3 protrude from the partition wall 46 into the interior of the water receiving section 45. Furthermore, the upper end of the partition wall 46 is provided with a cover 42 sandwiching a sealing member 43. As a result, the interior of the water receiving section 45 communicates with the ventilation path 50 via an opening 45c provided on its upper surface, but a space is formed where air circulation is substantially blocked from the interior of the housing 40.

In this embodiment, in addition to the first folded portions 31a2, 32a2 and the joint portions 31a3, 32a3, the inlet 31a5 and outlet 31a6 of the refrigerant pipe of the evaporator 31, and the joint portions between the inlet 32a5 and outlet 32a6 of the refrigerant pipe of the condenser 32 and the refrigerant transport pipes 36, 37, and 38 are also provided inside the water receiving portion 45.

In the washing machine and dryer of this embodiment, the evaporator 31 and condenser 32 are arranged such that the first folded sections 31a2, 31a2 and the joint sections 31a3, 31a3 are located in the ventilation path 50, and the straight sections 31a1, 32a1, the second folded sections 31a4, 32a4 and the fins 31b, 32b are located within the heat exchange section 30 that constitutes the circulating air passage 20. While the joint sections 31a3, 32a3, joined by brazing, have a higher possibility of refrigerant leakage compared to other parts of the refrigerant pipes and refrigerant transport pipes 36, 37, 38, in the washing machine and dryer of this embodiment, even if flammable refrigerant leaks from the joint sections 31a3, 32a3, it is difficult for the flammable refrigerant to enter the circulating air passage 20, where ignition sources such as static electricity are likely to occur, thus suppressing ignition.

In this embodiment, since the first opening 51 is provided in the base plate 1b on which the heat exchange unit 30 and compressor 33 are mounted, if the flammable refrigerant has a higher specific gravity than air, the leaked refrigerant will travel along the base plate 1b and be discharged to the outside of the housing 1 through the first opening 51.

Furthermore, when the heat pump 35 and blower 27 are operating, the rising airflow generated within the ventilation path 50 by the heat from the compressor 33 and fan motor 27b allows the flammable refrigerant to be discharged to the outside of the housing 1.

Furthermore, in this embodiment, since the water receiving section 45 is provided so as to cover the lower part of the joints 31a3, 32a3 and the first folded sections 31a2, 32a2, even if condensation water adhering to the first folded sections 31a2 and joints 31a3 of the evaporator 31 drips down during the operation of the heat pump 35, it is possible to prevent the condensation water from reaching the fan motor 27b, compressor 33, condenser 53, etc., which are mounted on the base plate 1b. Moreover, since the water receiving section 45 has an opening 45c on its upper side, even if flammable refrigerant leaks from the joints 31a3, 32a3, it can be discharged to the outside of the housing 1 through the ventilation path 50 via the opening 45c.

Furthermore, in this embodiment, a sealing member 43 is provided in the partition wall 46 separating the water receiving section 45 from the housing 40 of the heat exchange section 30, thereby sealing the housing 40 and the water receiving section 45. This allows for the blocking of airflow between the housing 40 and the water receiving section 45. Therefore, even when the heat exchange section 30 experiences negative pressure during the operation of the blower 27, it is possible to prevent flammable refrigerant leaking from the joints 31a3 and 32a3 from entering the heat exchange section 30 from the water receiving section 45.

Furthermore, in this embodiment, since a partition is provided between the condenser 53 mounted on the base plate 1b and the joints 31a3 and 32a3 of the evaporator 31 and condenser 32, even if refrigerant leaks from the joints 31a3 and 32a3 and flows along the base plate 1b, it is possible to prevent flammable refrigerant from reaching the vicinity of the condenser 53, particularly the connection terminals of the condenser 53, which are the charging part and could become an ignition source such as sparks.

(Example of change 1)
In the embodiment described above, the case in which the joints 31a3, 32a3 and the first folded portions 31a2, 32a2 provided on the outside of the heat exchange section 30 in the evaporator 31 and condenser 32 are exposed to the ventilation path 50 has been explained. However, for example, as shown in Figure 6, a porous material such as foamed urethane may be filled into the water receiving section 45 and the joints 31a3, 32a3 and the first folded portions 31a2, 32a2 may be covered with the porous material 55. In such a case, heat leakage from the joints 31a3, 32a3 and the first folded portions 31a2, 32a2 can be suppressed and the thermal efficiency in the heat exchange section 30 can be improved. Furthermore, even if refrigerant leaks from the joints 31a3, 32a3, the refrigerant will be slowly released into the ventilation path 50, preventing the inside of the housing 1 from reaching the ignition limit concentration.

(Example of change 2)
In the above-described embodiment, a washing machine and dryer without a refrigerant detection sensor was explained. However, for example, a gas sensor for detecting refrigerant leaking from the heat pump 35 may be provided in the ventilation path 50 or the circulating air passage 20.

1...Housing, 1a...Outer box, 1b...Base plate, 8...Water tank, 10...Exhaust port, 11...Air intake port, 17...Drum motor, 20...Circulating air passage, 22...Exhaust duct, 26...Air intake duct, 27...Blower, 27a...Sirocco fan, 27b...Fan motor, 30...Heat exchange section, 31...Evaporator, 31a1...Straight section, 31a2...First folded section, 31a3...Joint section, 31a4...Second folded section, 31b...Fin, 32...Condenser, 32a1...Straight section, 32a 2...First folded section, 32a3...Joint section, 32a4...Second folded section, 32b...Fin, 33...Compressor, 35...Heat pump, 36...Refrigerant transport pipe, 37...Refrigerant transport pipe, 38...Refrigerant transport pipe, 40...Housing, 41...Lower member, 42...Lid, 43...Sealing member, 45...Water receiving chamber, 45c...Opening, 46...Partition, 50...Ventilation path, 51...First opening, 52...Second opening, 53...Condenser, 54...Screen, 55...Porous body

Claims (1)

A drying room for storing clothes,
A circulating air passage whose ends are connected to the drying chamber,
A blower that circulates air between the drying chamber and the circulating air passage,
A heat pump comprising a condenser for heating the air in the circulating air passage, an evaporator for cooling and dehumidifying the air in the circulating air passage, a compressor for compressing a flammable refrigerant and supplying it to the condenser, and a depressurization means for reducing the pressure of the flammable refrigerant that has passed through the condenser, all connected by a refrigerant transport pipe,
In a clothes dryer comprising a drying chamber, a circulating air passage, a blower, and a housing for the heat pump,
The housing is provided with an opening that connects the inside and outside of the housing,
The condenser and the evaporator each include a refrigerant pipe through which a flammable refrigerant flows, and fins attached to the refrigerant pipe, the refrigerant pipe comprising a plurality of straight sections to which the fins are attached, a first folded section provided to connect one end of the plurality of straight sections, a joint section joining one end of the plurality of straight sections to the first folded section , and a second folded section folded at the other end of the plurality of straight sections and integrally provided with the plurality of straight sections .
A clothes dryer in which the plurality of straight sections and the second folded section are located inside the circulating air passage, and the joint is located outside the circulating air passage.