Patent Application
20100199512
The present invention relates to a dryer for drying garments, particularly to a garment dryer usable for a washing/drying machine. The invention further relates to a heat pump unit for use in the dryer.
A device for heating air for drying garments and a dehumidifier for dehumidifying wet air resulting from heat exchange between hot air and garments are provided in an electric washing machine, a washing/drying machine, a garment dryer and the like. Conventionally, the air heating device is generally configured to generate hot air by means of an electric heater or the like, and the dehumidifier is generally configured to dehumidify wet air by means of cooling water. It has been recently proposed to employ a heat pump device having a higher energy efficiency for the heating of the air and the dehumidification of the wet air resulting from the heat exchange with the hot air.
In general, the heat pump device includes a compressor which compresses a coolant, a radiator which releases heat of the compressed coolant, an expansion valve for reducing the pressure of the coolant compressed to a higher pressure, a heat absorber in which the coolant having a reduced pressure removes heat from the ambient atmosphere, and a pipe which connects the compressor, the radiator, the expansion valve and the heat absorber for circulation of the coolant. Where the heat pump device, which has a greater number of components, is incorporated in a washing/drying machine, for example, a special arrangement should be designed in consideration of an available space in a housing of the washing/drying machine.
Prior art solutions to this problem are proposed in Patent Document 1, Patent Document 2 and Patent Document 3.
A garment dryer described in Patent Document 1 is configured such that a heat absorber and a radiator of a heat pump device are disposed parallel to each other, and inclined in the same direction as a rear surface of a drum.
A garment dryer described in Patent Document 2 is configured such that a heat absorber and a radiator of a heat pump device are disposed parallel to each other, and the heat absorber is located at a higher position than the radiator.
A garment dryer described in Patent Document 3 is configured such that a heat absorber and a radiator of a heat pump device are disposed in a generally V-shaped configuration as seen from a lateral side to cause air to flow down around the heat absorber and flow up around the radiator, and an air passage is provided above the radiator for horizontal airflow.
The inventors of the present invention checked the airflow around a heat exchanger (the heat absorber and the radiator) in each of the heat pump devices described in Patent Documents 1 to 3. As a result, the inventors found that the air unevenly flows around the heat absorber and/or the radiator, i.e., uneven airflow occurs, in each of the heat pump devices.
In general, the heat exchange efficiency is improved for reduction of a drying period by causing the air to uniformly flow around the heat exchanger (the heat absorber and the radiator) in the heat pump devices. The heat pump devices proposed in Patent Documents 1 to 3 suffer from the uneven airflow, each failing to exhibit a sufficient heat exchange capability. Therefore, the heat exchange capability and the drying efficiency are disadvantageously poor.
In order to solve the aforementioned problem, it is a principal object of the present invention to provide a garment dryer which includes a heat pump device and has a heat exchange capability improved by causing air to uniformly flow around a heat exchanger (a heat absorber and a radiator).
It is another object of the present invention to provide a garment dryer which includes a heat pump device properly accommodated in a housing thereof, and ensures uniform airflow around a heat exchanger thereof for circulation.
It is further another object of the present invention to provide a heat pump unit which can be incorporated in a garment dryer, and is compact in structure and excellent in heat exchange efficiency.
According to one aspect of the present invention, there is provided a garment dryer, which includes: a treatment tub in which a garment to be dried is retained; an air circulation duct having opposite ends connected to the treatment tub for causing air to flow out of the treatment tub through one of the opposite ends and flow back into the treatment tub through the other end; air blowing means for circulating the air through the air circulation duct; and a heat pump device including a heat absorber, a compressor, a radiator and pressure reducing means which are connected by a coolant pipe through which a coolant flows, the heat absorber being adapted to cool the air flowing through the air circulation duct to dehumidify the air, the radiator being adapted to heat the dehumidified air; wherein the heat absorber and the radiator each have an airflow plane for heat exchange with the air, and the airflow plane of the heat absorber and the airflow plane of the radiator are disposed in this order with respect to an airflow direction in opposed relation in the air circulation duct; wherein the air circulation duct includes an upstream buffer space provided upstream of the airflow plane of the heat absorber with respect to the airflow direction for changing the flow direction of the air to regulate the flow rate of the air.
In the garment dryer according to this inventive aspect, the air circulation duct includes a downstream buffer space provided downstream of the airflow plane of the radiator with respect to the airflow direction for uniformly regulating the flow rate of the air.
In the garment dryer according to this inventive aspect, the air blowing means is disposed downstream of the downstream buffer space with respect to the airflow direction.
According to another aspect of the present invention, there is provided a garment dryer, which includes: a treatment tub in which a garment to be dried is retained; an air circulation duct having opposite ends connected to the treatment tub for causing air to flow out of the treatment tub through one of the opposite ends and flow back into the treatment tub through the other end; air blowing means for circulating the air through the air circulation duct; and a heat pump device including a heat absorber, a compressor, a radiator and pressure reducing means which are connected by a coolant pipe through which a coolant flows, the heat absorber being adapted to cool the air flowing through the air circulation duct to dehumidify the air, the radiator being adapted to heat the dehumidified air; wherein the air circulation duct includes a heat exchange air duct portion in which the heat absorber and the radiator are incorporated; wherein the heat exchange air duct portion has an airflow direction extending generally horizontally; wherein the heat absorber and the radiator each have an airflow plane disposed in the heat exchange air duct portion as inclined with respect to the airflow direction as seen in plan.
In the garment dryer according to this inventive aspect, the heat exchange air duct portion includes an upstream buffer space provided upstream of the heat absorber.
In the garment dryer according to this inventive aspect, the heat exchange air duct portion includes a downstream buffer space provided downstream of the radiator for uniformly regulating the flow rate of the air.
In the garment dryer according to this inventive aspect, the air blowing means is provided horizontally downstream of the downstream buffer space
In the garment dryer according to this inventive aspect, the air circulation duct includes an air duct portion through which the air flows into the upstream buffer space from a horizontal upper portion of the upstream buffer space.
According to further another aspect of the present invention, there is provided a heat pump unit for the garment dryer, the heat exchange air duct portion being unitized by a casing having a generally rectangular box shape, the heat pump unit including: a heat exchange air duct defined in the casing and having an airflow direction extending generally horizontally; and a compressor and pressure reducing means provided outside the heat exchange air duct.
According to the present invention, the upstream buffer space is provided upstream of the heat absorber, so that the direction and the flow rate of the air flowing to the heat exchanger (the heat absorber and the radiator) can be regulated. As a result, the air uniformly flows to the heat exchanger, thereby improving the heat exchange efficiency.
Further, the heat absorber and the radiator are disposed in this order with respect to the airflow direction in opposed relation. Therefore, the installation space of the heat absorber and the radiator is reduced, so that the heat pump device has a compact structure. This makes it possible to properly incorporate the heat pump device in the garment dryer.
According to the present invention, the downstream buffer space is provided downstream of the heat absorber and the radiator, i.e., downstream of the heat exchanger, so that the air evenly and uniformly flows around the heat exchanger (the heat absorber and the radiator). This improves the heat exchange efficiency.
According to the present invention, the air blowing means is disposed downstream of the downstream buffer space. Therefore, the air is sucked by the air blowing means to cause the air to flow around the heat exchanger (the heat absorber and the radiator). The airflow around the heat exchanger can be made more uniform by sucking the air having passed around the heat exchanger than by feeding air to the heat exchanger. This improves the heat exchange efficiency.
According to the present invention, the airflow direction extends generally horizontally in the heat exchange air duct portion in which the heat exchanger (the heat absorber and the radiator) is provided. Therefore, the heat exchange air duct portion can be located in a housing of the garment dryer, for example, along a bottom surface, a rear surface, a side surface or a front surface of the housing.
Further, the airflow planes of the heat absorber and the radiator are inclined with respect to the airflow direction as seen in plane in the heat exchange air duct portion and, therefore, each have a larger area. This improves the heat exchange efficiency.
According to the present invention, the direction and the flow rate of the air flowing to the heat exchanger (the heat absorber and the radiator) are regulated by the upstream buffer space, so that the air can uniformly flow around the heat exchanger.
According to the present invention, the airflow around the heat exchanger (the heat absorber and the radiator) is regulated uniformly by the downstream buffer space. This improves the heat exchange efficiency.
According to the present invention, the air is sucked by the air blowing means provided downstream of the heat exchanger (the heat absorber and the radiator) to cause the air to flow around the heat exchanger. Therefore, the airflow around the heat exchanger can be regulated more uniformly.
According to the present invention, the heat exchange air duct portion can be disposed on the bottom of the housing of the garment dryer. Therefore, the heat pump device can be properly incorporated in an empty space on the bottom.
According to the present invention, the compressor and the pressure reducing means are combined with the heat exchange air duct portion into a generally rectangular box shape to be unitized into the heat pump unit. Therefore, the heat pump unit can be easily incorporated in the housing of the garment dryer.
A specific embodiment of the present invention will hereinafter be described with reference to the drawings.
Referring to
For washing, the garments are loaded into the rotary drum 7 from the port 5, and a predetermined amount of water is retained in the outer tub 6. Then, the rotary drum 7 is rotated. For dehydration, the water is drained from the outer tub 6, and the rotary drum 7 is rotated at a higher speed.
A DD motor 8 for rotating the rotary drum 7 is fixed to a rear surface of the outer tub 6.
An air circulation duct 10 is connected to an outer portion of the treatment tub 4. When the garments retained in the rotary drum 7 are dried in a drying process, air is circulated from the treatment tub 4 through the air circulation duct 10.
More specifically, the air circulation duct 10 is a concatenation structure which includes an air outlet duct 11 having one end connected to a front portion of an upper surface of the outer tub 6, a lint filter unit 12 connected to the other end of the air outlet duct 11, a downward air duct 13 having an upper end connected to the lint filter unit 12 and extending downward on a rear side of the outer tub 6, a heat pump unit 14 connected to a lower end of the downward air duct 13 and horizontally disposed as extending laterally along a rear edge of the base frame 2, an air blower unit 15 attached to one of opposite ends of the heat pump unit 14, and an air inlet duct 16 having a lower end connected an upper portion of the air blower unit 15 and an upper end connected to an upper portion of the rear surface of the outer tub 6. The air is circulated from the treatment tub 4 through the concatenation structure, i.e., the air circulation duct 10, in an arrow direction A1.
One feature of the washing/drying machine 1 according to this embodiment is that the air circulation duct 10 to be utilized for the drying process, particularly, the heat pump unit 14 and the air blower unit 15 of the air circulation duct 10, is configured in the following unique manner.
Specifically, the heat pump unit 14 has a generally rectangular box-like outer shape, and is disposed laterally along the rear edge of the base frame 2. The air blower unit 15 is fixed to one side surface of the heat pump unit 14. With this arrangement, an empty space present above the base frame 2 can be effectively utilized to accommodate the heat pump unit 14 and the air blower unit 15 on a rear lower side of the treatment tub 6. Further, as will be described later, the air being circulated flows laterally horizontally in the heat pump unit 14, so that highly efficient heat exchange can be achieved in the heat pump unit 14.
Further, the air blower unit 15 is disposed downstream of the heat pump unit 14 with respect to an airflow direction in the air circulation duct 10, so that the air is sucked out of the heat pump unit 14 and the sucked air is fed into the air inlet duct 16. Thus, the air blower unit 15 is of the type adapted to suck the air out of the heat pump unit 14. Therefore, as will be described later, the air can flow through the heat pump unit 14 at a generally uniform flow rate. This improves the heat exchange efficiency.
Other components illustrated in
In
Referring to
A compressor 25, an expansion valve 2 (pressure reducing means) and a coolant pipe 27 through which a coolant flows are disposed in a region of the casing 20 which does not hinder the airflow in the heat exchange air duct portion 22, i.e., disposed outside a region defined as the heat exchange air duct portion 22. The heat absorber 23, the compressor 25, the radiator 24 and the expansion valve 26 are connected by the coolant pipe 27 so that the coolant flows through the heat absorber 23, the compressor 25, the radiator 24 and the expansion valve 26 in this order.
The coolant flowing through the coolant pipe 27 repeatedly experiences the following state change. The pressure of the coolant is steeply reduced by the expansion valve 26, whereby the temperature of the coolant is reduced to a lower level. The lower temperature coolant is applied to the heat absorber 23. Therefore, the lower temperature coolant and the air flowing through the heat exchange air duct portion 22 are heat-exchanged by the heat absorber 23, whereby the air is cooled. The coolant having passed through the heat absorber 23 is applied to the compressor 25 through the coolant pipe 27. The coolant is compressed by the compressor 25, whereby the temperature of the coolant is increased to a higher level. The higher temperature coolant is applied to the radiator 24 through the coolant pipe 27. The higher temperature coolant and the air flowing through the heat exchange air duct portion 22 are heat-exchanged by the radiator 24, whereby the air flowing through the heat exchange air duct portion 22 is heated. Then, the coolant flows into the expansion valve 26 through the coolant pipe, whereby the coolant has a reduced pressure and hence has a reduced temperature again.
Next, the configuration of the heat exchange air duct portion 22 will be described. As shown in
More specific description will be given with reference to
As shown in
The sub-casing 21 is thus provided in an air inlet passage to the casing 20, whereby a buffer space 30 is defined in which the airflow is deflected from the downward direction to the lateral direction around the sub-casing 21 to be regulated uniformly with respect to the height.
Then, the air caused to flow uniformly with respect to the height in the buffer space 30 flows laterally into an upstream buffer space 33 as will be described below. In the upstream buffer space 33, the flow direction and the flow rate of the air is regulated. After the air flows to the heat exchanger, the airflow is regulated more uniformly in a downstream buffer space 34 provided downstream of the heat exchanger.
Where a flow passage through which the air flows into the upstream buffer space 33 from the buffer space 30 is bent in a chevron plan shape as indicated by an arrow A in
As shown in
Next, the downstream buffer space will be described. Referring mainly to
From another viewpoint, the heat absorber 23 and the radiator 24 are spaced parallel to each other the predetermined distance, and the portion of the upstream buffer space 33 having the greater width W1 is opposed to the one edge of the airflow plane of the heat absorber 23. On the other hand, the portion of the downstream buffer space 34 having the smaller width W3 is opposed to the one edge of the airflow plane of the radiator 24.
Further, the portion of the upstream buffer space 33 having the smaller width W2 is opposed to the other edge of the airflow plane of the heat absorber 23, and the portion of the downstream buffer space 34 having the greater width W4 is opposed to the other edge of the airflow plane of the radiator 24.
Mainly in consideration of the heat absorber 23 and the radiator 24, the heat exchange air duct portion 22 is designed so that the total space width of the space opposed to the airflow plane of the heat absorber 23 on an inlet side and the space opposed to the airflow plane of the radiator 24 on an outlet side is generally constant over the airflow planes without significant local differences.
That is, the heat exchange air duct portion 22 is designed so that the total volume of the spaces on the inlet side and the outlet side of the heat exchanger (the heat absorber 23 and the radiator 24) is generally constant over the airflow planes with the provision of the upstream buffer space 33 and the downstream buffer space 34 on the upstream side and the downstream side of the heat exchanger (the heat absorber 23 and the radiator 24). Thus, the air can substantially uniformly flow around the heat exchanger (the heat absorber 23 and the radiator 24). As a result, the heat exchange efficiency of the heat exchanger (the heat absorber 23 and the radiator 24) is improved.
In the heat exchange air duct portion 22 defined in the casing 20, the air flows generally horizontally. Therefore, the heat exchange air duct portion 22 is free from uneven airflow. This improves the heat exchange efficiency.
In the embodiment described above, the upstream buffer space 33 and the downstream buffer space 34 each have a triangular space as seen in plan by way of example, but the shapes of the upstream buffer space 33 and the downstream buffer space 34 are not limited to this shape. The upstream buffer space 33 and the downstream buffer space 34 may each have a gradational shape, or may have a shape such as a polygonal shape having a gradational sectional area. Even in this case, the air flows uniformly as in the aforementioned embodiment. This also provides the effects of the invention.
The air blower unit 15 is connected to the one side surface of the heat pump unit 14. More specifically, the air blower unit 15 is connected to the one side of the casing 20 so that the air can be sucked out through the portion of the downstream buffer space 34 having the greater width W4.
The air blower unit 15 includes an annular turbo fan 35, a fan case 36 for guiding air fed by the turbo fan 35, and a fan motor 37 provided outside the fan case 36 for rotating the turbo fan 35. When the turbo fan 35 is rotated by the fan motor 37, the air is sucked from a center portion of the annular turbo fan, and the sucked air is released radially outward. Then, the air is fed into the air inlet duct 16 (see
The air blower unit 15 connected to the one side surface of the heat pump unit 14 sucks the air out of the downstream buffer space 34 into the treatment tub 4 as previously described. Since the heat pump unit 14 is configured so that the air is sucked out of the heat exchange air duct portion 22, the air can more uniformly flow over the heat absorber 23 and the radiator 24 as compared with a configuration adapted to squeeze the air into the heat exchange air duct portion 22. With the heat pump unit 14 and the air blower unit 15 according to this embodiment, the upstream buffer space 33 and the downstream buffer space 34 are respectively provided upstream and downstream of the heat absorber 23 and the radiator 34, whereby the air can substantially uniformly flow around the heat absorber 23 and the radiator 24. Further, the air blower unit 15 for causing the air to flow is of the type adapted to suck the air out of the heat exchange air duct portion 22, so that the air can more uniformly flow around the heat absorber 23 and the radiator 24. As a result, the efficiency of the heat exchange by the heat absorber 23 and the radiator 24 can be improved.
The comparative graph indicates that the uniformity of the airflow distribution A0 of the air flowing to the heat absorber 23 according to this embodiment is improved over the prior arts.
In the embodiment described above, the expansion valve 26 is provided as the pressure reducing means in the heat pump unit 14. The pressure reducing means is not limited to the expansion valve, but may be, for example, a capillary tube.
In the embodiment described above, the heat pump unit 14 and the air blower unit 15 are provided as a part of a dryer functional section (air circulation duct) in the washing/drying machine 1 by way of example. The present invention is applicable not only to the washing/drying machine 1 but also to a standalone garment dryer.
The heat pump unit has a generally rectangular box shape, which is universal and permits easy incorporation thereof in an electric washing machine, a washing/drying machine, a garment dryer and the like. Therefore, the heat pump unit can be incorporated in a drying functional section of any of various types of dryers.
Examples of the coolant for the heat pump include HFCs (hydrofluorocarbons) and CO2. Where CO2 is employed as the coolant in the present invention, CO2 may be used in a supercritical state.
The present invention is not limited to the embodiment described above, but various modifications may be made within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-244263 | Sep 2007 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2008/066854 | 9/18/2008 | WO | 00 | 3/4/2010 |
