Drying apparatus

Abstract

A drying apparatus has a heat pump apparatus having a compressor, a radiator, an expansion mechanism and an evaporator connected in this order via pipes through which a refrigerant is circulated. The drying apparatus has a structure in which drying air heated in the radiator is introduced into a subject to be dried, drying air obtained by removing moisture or water from the subject to be dried is cooled and dehumidified by the evaporator, and then the drying air is reheated in the radiator to be reused as renewed drying air. The drying apparatus also has a structure in which drain water generated by dehumidifying the drying air in the evaporator is dropped or sprayed into the radiator.

Description

TECHNICAL FIELD

The present invention relates to a drying apparatus with a heat pump apparatus that is constructed by circularly connecting a compressor, a radiator, a throttle apparatus and an evaporator.

BACKGROUND OF THE INVENTION

In an electric type cloth drier used in a general household, the quantity of heat required to dry clothes is converted from electric energy with an electric heater. Since the quantity of heat has a limitation due to a current capacity of an outlet for home use, it becomes an obstacle to shorten the time required to dry clothes. Further, since the heat used to dry the clothes is discharged to the outside thereof without reuse, there is wasted energy.

As for a conventional cloth drier, a low-power cloth drier with high dehumidification efficiency in which a heat pump apparatus is used as a heat source for drying clothes and a part of drying air is discharged to the outside thereof has been proposed (for example, see Japanese Patent Application Laid-open No. H7-178289 (in particular, pp. 4-5 and FIG. 1)). FIG. 13 is a conventional drying apparatus disclosed in Japanese Patent Application Laid-open No. H7-178289.

In the conventional drying apparatus shown in FIG. 13, a rotation drum 122 is rotatably provided in a drying apparatus body 121 and is a dry room for drying clothes 136 therein. The rotation drum 122 is operated by a motor 127 through a drum belt 135. A blower 123 sends drying air in a flow direction as indicated by arrows from the rotation drum 122 to a circulation duct 126 through a filter 124 and a rotation drum-side air intake 125. The blower 123 is operated by the motor 127 through a fan belt 128.

Further, an evaporator 129 provided within the circulation duct 126 cools and dehumidifies the drying air by evaporating a refrigerant, and a condenser 130 heats the drying air flowing in the circulation duct 126 by condensing the refrigerant. The heated drying air is introduced into the circulation duct 126 again, and returns to the dry room. A part of the drying air is discharged out of the drying apparatus body 121 through an exhaust port 134. A compressor 131 generates a pressure difference in the refrigerant, and an expansion mechanism 132 constituted from a capillary tube or the like maintains the pressure difference of the refrigerant. The heat pump apparatus is constructed by connecting the evaporator 129, the condenser 130, the compressor 131 and the expansion mechanism 132 in this order via pipes 133 through which the refrigerant flows.

On the other hand, HCFC refrigerant (refrigerant including toms of chlorine, hydrogen, fluorine and carbon in its molecule) or HFC refrigerant (refrigerant including atoms of hydrogen, fluorine and carbon in its molecule) are conventionally used as a refrigerant of the heat pump apparatus described above. However, since such a refrigerant directly affects the ozone depletion and the global warming, conversion into a natural refrigerant such as a hydrocarbon, carbon dioxide (hereinafter, referred to as CO₂) existing in the nature has been proposed as an alternative refrigerant.

Required electric energy can be reduced by switching from heating by means of an electric heater to heating by means of a heat pump. However, it is an essential condition to provide a compressor, a condenser, an expansion mechanism and an evaporator constituting the refrigeration cycle, at least. Thus, since many components are required in comparison with a drying apparatus in which an electric heater is used and such a drying apparatus has a large size, there is a problem to miniaturize such a drying apparatus.

In particular, taking the refrigeration cycle of the heat pump apparatus into consideration, quantity of heat discharged from the condenser to drying air is quantity of heat adding the quantity of heat corresponding to electric energy consumed in the compressor to quantity of heat drawn from the drying air in the evaporator. Thus, it is necessary to make the size of the condenser extremely larger than that of the evaporator and this makes the factor that the drying apparatus in which a heat pump is used increases in size.

On the other hand, using a natural refrigerant such as CO₂ which does not directly affect the ozone depletion and the global warming, there is a problem that it is necessary to realize energy conservation so as to reduce the indirect influence on the global warming.

The present invention has been accomplished to solve the conventional problems described above, and it is an object of the invention to provide a heat pump type drying apparatus in which when a refrigerant which can be brought into the supercritical state on the radiating side of the refrigeration cycle such as CO₂ is used, enlargement of the apparatus can be prevented and high efficiency is realized.

SUMMARY OF THE INVENTION

A first aspect of the present invention provides a drying apparatus including: a heat pump apparatus having a compressor, a radiator, a throttle apparatus and an evaporator connected in this order via pipes through which a refrigerant is circulated; a dry room wherein air heated in the radiator is introduced into the dry room, the air dried in the dry room is dehumidified by the evaporator, and the air dehumidified in the evaporator is reheated in the radiator; and a sprinkler mechanism for dropping or spraying water into the radiator.

According to a second aspect of the invention, in the drying apparatus of the first aspect, the sprinkler mechanism drops or sprays drain water generated by dehumidifying the air in the evaporator.

According to a third aspect of the invention, in the drying apparatus of the first aspect, the drying apparatus further includes a moisture collection mechanism for collecting moisture or water included in the air between the evaporator and the radiator.

According to a fourth aspect of the invention, in the drying apparatus of the first aspect, the drying apparatus further includes a pump, wherein the evaporator and the radiator are respectively constituted from a heat transfer tube and a fin, and wherein drain water generated by dehumidifying the air in the evaporator is drawn by the pump and the sprinkler mechanism drops or sprays the drain water into the radiator.

A fifth aspect of the present invention provides a drying apparatus including: a heat pump apparatus having a compressor, a radiator, a throttle apparatus and an evaporator connected in this order via pipes through which a refrigerant is circulated, the evaporator being provided above the radiator; a dry room wherein air heated in the radiator is introduced into the dry room, the air dried in the dry room is dehumidified by the evaporator, and the air dehumidified in the evaporator is reheated in the radiator, drain water being generated by dehumidifying the air in the evaporator; and a sprinkler mechanism for dropping or spraying the drain water into the radiator.

According to a sixth aspect of the invention, in the drying apparatus of the fifth aspect, the sprinkler mechanism drops the drain water into the radiator by means of gravity of the drain water or force of wind.

According to a seventh aspect of the invention, in the drying apparatus of the fifth aspect, the evaporator includes a fin having a lower end surface with respect to the direction of gravity, the lower end surface having a saw-toothed structure.

According to an eighth aspect of the invention, in the drying apparatus of the sixth aspect, the evaporator includes a fin having a fin base, the fin being a corrugated fin in which the fin base is folded.

According to a ninth aspect of the invention, in the drying apparatus of the fifth aspect, the drying apparatus further includes a pump, wherein the evaporator and the radiator are respectively constituted from a heat transfer tube and a fin, and wherein drain water generated by dehumidifying the air in the evaporator is drawn by the pump and the sprinkler mechanism drops or sprays the drain water into the radiator.

According to a tenth aspect of the invention, in the drying apparatus of the fifth aspect, the drying apparatus further includes a moisture collection mechanism for collecting moisture or water included in the air between the evaporator and the radiator.

An eleventh aspect of the present invention provides a drying apparatus including: a heat pump apparatus having a compressor, a radiator, a throttle apparatus, a first evaporator and a second evaporator connected in this order via pipes through which a refrigerant is circulated; a dry room wherein air heated in the radiator is introduced into the dry room, the air dried in the dry room is dehumidified by the first and second evaporators, and the air dehumidified in the first and second evaporators is reheated in the radiator; a drainage mechanism for draining drain water generated by dehumidifying the air in the first evaporator; and a sprinkler mechanism for dropping or spraying drain water generated by dehumidifying the air in the second evaporator into the radiator.

According to a twelfth aspect of the invention, in the drying apparatus of the eleventh aspect, the drying apparatus further comprising a moisture collection mechanism for collecting moisture or water included in the air between the second evaporator and the radiator.

According to a thirteenth aspect of the invention, in the drying apparatus of the eleventh aspect, the heat pump apparatus further has a bypass circuit through which the refrigerant bypasses the second evaporator.

According to a fourteenth aspect of the invention, in the drying apparatus of any one of the first, fifth or eleventh aspect, the heat pump apparatus sets the temperature of the refrigerant run into the radiator to the temperature of boiling water or more.

According to a fifteenth aspect of the invention, in the drying apparatus of any one of the first, fifth or eleventh aspect, the heat pump apparatus has a high pressure side and is constructed to operate so that the pressure of the high pressure side thereof becomes supercritical pressure.

According to a sixteenth aspect of the invention, in the drying apparatus of any one of the first, fifth or eleventh aspect, a refrigerant in which the pressure at the high pressure side of the heat pump apparatus becomes supercritical pressure is used as the refrigerant.

According to a seventeen aspect of the invention, in the drying apparatus of the first aspect, the drying apparatus further includes: a circulation duct; and a radiation mechanism which radiates the quantity of heat of the drying air outside the circulation duct.

According to a eighteenth aspect of the invention, in the drying apparatus of the seventeenth aspect, the radiation mechanism is a heat exchanger for roughly drawing from drying air, the radiation mechanism being provided across the inside and outside of the circulation duct.

According to a nineteenth aspect of the invention, in the drying apparatus of the fifth aspect, the drying apparatus further includes: a circulation duct; and a radiation mechanism which radiates the quantity of heat of the drying air outside the circulation duct.

According to a twentieth aspect of the invention, in the drying apparatus of the nineteenth aspect, the radiation mechanism is a heat exchanger for roughly drawing from drying air, the radiation mechanism being provided across the inside and outside of the circulation duct.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a drying apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a drying apparatus according to a second embodiment of the present invention.

FIG. 3 is an enlarged view of a main portion of a fin constituting the evaporator according to the second embodiment of the present invention.

FIG. 4(a) is a cross-sectional view of a main portion of another fin constituting the evaporator of the drying apparatus according to the second embodiment of the present invention, and FIG. 4(b) is an enlarged view of a main portion of another fin constituting the evaporator according to the second embodiment of the present invention.

FIG. 5 is a block diagram of a drying apparatus according to a third embodiment of the present invention.

FIG. 6 is a block diagram of a drying apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram of a drying apparatus according to a fifth embodiment of the present invention.

FIG. 8 is a block diagram of a drying apparatus according to a sixth embodiment of the present invention.

FIG. 9 is a block diagram of a drying apparatus according to a seventh embodiment of the present invention.

FIG. 10 is a block diagram of a drying apparatus according to an eighth embodiment of the present invention.

FIG. 11 is a drawing which shows temperature changes in refrigerant and air in the radiator of a drying apparatus according to a ninth embodiment of the present invention.

FIG. 12 is a drawing which shows temperature changes in refrigerant and air in the radiator of the drying apparatus in case of using a CFC refrigerant.

FIG. 13 is a block diagram of a conventional drying apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will now be described with reference to the drawings.

First Embodiment

FIG. 1 is a block diagram of a drying apparatus according to a first embodiment of the present invention. Referring to FIG. 1, a reference number 31 represents a compressor, a reference number 32 represents a radiator, a reference number 33 represents an expansion valve (expansion mechanism), and a reference number 34 represents an evaporator. A heat pump apparatus is constructed by connecting these constituent elements to one another in this order through pipes and charging a refrigerant thereinto. As the refrigerant, a refrigerant which can be brought into the supercritical state on the radiation side (from a discharge section of the compressor 31, to the radiator 32 and to an inset section of the expansion mechanism 33) such as a CO₂ refrigerant is charged thereinto. A reference number 36 represents a subject to be dried (for example, clothes, a bathroom space, or the like), a reference number 37 represents a blower fan, a reference number 38 represents a heat exchanger for roughly drawing heat from drying air, a reference number 39 represents a blower fan for the heat exchanger 38 for roughly drawing heat from the drying air, and a reference number 40 represents a pan for drain water, and a reference number 10 represents a moisture collection mechanism. The evaporator 34 is provided at the windward side of the radiator 32 and above the radiator 32 in the direction of gravity. Further, the drying apparatus is constructed so that the moisture collection mechanism 10 is provided between the radiator 32 and the evaporator 34. In FIG. 1, solid arrows indicate the flow of the refrigerant, hollow arrows indicate the flow of the drying air, and a hollow arrow with diagonal lines indicates the flow of outside air.

Next, an operation of the drying apparatus of the first embodiment will be described. The refrigerant is compressed by the compressor 31 and brought into a high temperature and high pressure state. The refrigerant is heat-exchanged in the radiator 32 with drying air received from the evaporator 34, and the refrigerant heats the drying air. This makes the refrigerant cooled. The refrigerant is then decompressed by the expansion mechanism 33, and is brought into a low temperature and low pressure state. The refrigerant is heat-exchanged with drying air which passes through the subject 36 by the evaporator 34, thereby cooling the drying air. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and the refrigerant is again sucked into the compressor 31. Therefore, the drying air cooled and dehumidified by the evaporator 34 is heated by the radiator 32, and is brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state removes moisture or water from the subject 36 and is brought into a humid state when the drying air is forcibly brought into contact with the subject 36 by the blower fan 37. After the temperature of the drying air is lowered by heat-exchanging it with the outside air in the heat exchanger 38, the drying air is again cooled and dehumidified by the evaporator 34.

By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 36.

In the present embodiment, the refrigerant is heat-exchanged with the humid drying air which passes through the subject 36 by the evaporator 34, thereby cooling the drying air. The moisture or water Included in the drying air is condensed on the surface of a fin of the evaporator 34, and resulting drain water is dropped into the radiator 32 using gravity thereof and shearing force due to blowing. Since the drying apparatus of the present embodiment has a structure described above, sensible heat exchange with the drying air and latent heat exchange with the drain water are carried out in the radiator 32, thereby accelerating heat transfer. As a result, since the amount of heat exchange at the radiator 32 is increased and heat transfer to the refrigerant that flows inside the radiator 32 is accelerated, it is possible to miniaturize the size of the radiator 32 similar to that of the evaporator 34. Therefore, it is possible to miniaturize the heat pump apparatus.

In the case of taking the structure in which the drain water generated in the evaporator 34 is dropped into the radiator 32, it is possible to increase the ability of the radiator as described above. However, since the drying apparatus is an air cycle of a circulation system, water is reevaporated in the radiator to increase the humidity of air. Thus, the system COP is improved, but the amount of drying time for drying the subject to be dried is increased, and the amount of power consumption of the drying apparatus is improved after all. It becomes important in the drying apparatus how moisture (humidity) of the drying air which passes through the radiator is removed. Accordingly, in the present invention, the moisture collection mechanism 10 for collecting moisture or water included in the air between the evaporator and the radiator is provided, whereby the humidity of the drying air which passes through the radiator 32 is lowered. As a result, it is possible to realize the low amount of power consumption without increasing the drying time.

Further, since the heat transfer in the radiator 32 is accelerated, the temperature of the refrigerant is lowered at an outlet of the radiator 32 and cooling capacity of the evaporator 34 is increased, whereby energy conservation can be realized.

Moreover, in the case of using the CO₂ refrigerant which can be brought into the supercritical state on the radiation side of the drying apparatus among natural refrigerants which have little influence on the global environment, the refrigerant is brought into a near-critical refrigeration cycle. Thus, the temperature of the refrigerant is lowered at the outlet of the radiator 32, and this results in the effort that it is possible to improve the refrigeration cycle COP largely, whereby it is possible to realize energy conservation further.

Furthermore, since the drying apparatus utilizes near critical refrigeration cycle in which a CO₂ refrigerant is used, in comparison with the case of the subcritical refrigeration cycle in which a conventional HFC refrigerant is used, it is possible heighten heat exchange efficiency in which the high temperature CO₂ refrigerant is heat-exchanged with the drying air in the radiator 32, whereby it is possible to raise the temperature of the drying air to a high temperature. Therefore, the ability to remove moisture or water from the subject 36 can be increased, whereby the drying operation can be carried out in a short time.

In this regard, it should be noted that although the expansion valve is used as the expansion mechanism in the present embodiment, the same effect can be obtained even if a capillary tube is used as the expansion mechanism.

Further, the CO₂ refrigerant which can be brought into the supercritical state on the radiation side is used in the present embodiment. However, even in the case the conventional HFC refrigerant is used, by dropping drain water generated in an evaporator into a radiator, the amount of heat exchange in the radiator can be increased in the same manner. Therefore, it is possible to miniaturize the size of the radiator, and this makes it possible to miniaturize the heat pump apparatus.

Second Embodiment

Hereinafter, a second embodiment of the present invention will now be described with reference to the drawings.

FIG. 2 is a block diagram of a drying apparatus according to a second embodiment of the present invention. FIG. 3 is an enlarged view of a main portion of a fin constituting an evaporator according to the second embodiment of the present invention. In FIG. 2, common constituent elements shown in FIG. 1 are designated with the same reference numbers, and explanation thereof will be omitted. A reference number 31 represents a compressor, a reference number 42 represents a radiator, a reference number 33 represents an expansion valve (expansion mechanism), and a reference number 44 represents an evaporator. A heat pump apparatus is constructed by connecting these constituent elements to one another in this order through pipes and charging a refrigerant thereinto. As the refrigerant, a CO₂ refrigerant which can be brought into the supercritical state on the radiation side is charged thereinto. Differences between the first and second embodiments are a point that the evaporator 44 and the radiator 42 are provided on a slant and a point that a saw-toothed structure 46 is formed on a lower end surface of a fin 45 constituting the evaporator 44 with respect to the direction of gravity. The point that the evaporator 44 is provided at the windward side of the radiator 42 and above the radiator 42 in the direction of gravity is the same. In FIG. 2, solid arrows indicate the flow of the refrigerant, hollow arrows indicate the flow of the drying air, and a hollow arrow with diagonal lines indicates the flow of outside air.

Next, an operation of the drying apparatus of the second embodiment will be described. The refrigerant is compressed by the compressor 31 and brought into a high temperature and high pressure state. The refrigerant is heat-exchanged in the radiator 42 with drying air received from the evaporator 44, and the refrigerant heats the drying air. This makes the refrigerant cooled. The refrigerant is then decompressed by the expansion mechanism 33, and is brought into a low temperature and low pressure state. The refrigerant is heat-exchanged with drying air which passes through the subject 36 by the evaporator 44, thereby cooling the drying air. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and the refrigerant is again sucked into the compressor 31. Therefore, the drying air cooled and dehumidified by the evaporator 44 is heated by the radiator 42, and is brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state removes moisture or water from the subject 36 and is brought into a humid state when the drying air is forcibly brought into contact with the subject 36 by the blower fan 37. After the temperature of the drying air is lowered by heat-exchanging it with the outside air in the heat exchanger 38, the drying air is again cooled and dehumidified by the evaporator 44.

By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 36.

In the present embodiment, since the evaporator 44 and the radiator 42 are provided on a slant, it is possible to reduce the installation space of the heat exchanger, and this makes it possible to miniaturize a heat pump type drying apparatus. Further, since the saw-toothed structure 46 (convex portion 46a) is formed on the lower end surface of the fin 45 with respect to the direction of gravity, drain water generated and condensed by dehumidifying the drying air on the surface of the fin 45 of the evaporator 44 is concentrated on the convex portions 46a to form droplets 47. The droplets 47 grow up and drop into the radiator 42 using gravity thereof and shearing force due to blowing. Since the droplets 47 are formed by concentrating the drain water on the convex portions 46a in this way, there is no instability of places where the droplets 47 are formed. By uniformly forming the convex portions 46a over the evaporator 44 on which the droplets 47 are formed, since the droplets 47 drop into the radiator 42 uniformly, a liquid film of the drain water is formed over the radiator 42 uniformly. Thus, sensible heat exchange with the drying air and latent heat exchange with the drain water are carried out in the radiator 42, thereby accelerating heat transfer. As a result, since the amount of heat exchange is increased and heat transfer to the refrigerant that flows inside the radiator 42 is accelerated, it is possible to further miniaturize the size of the radiator 42. Therefore, it is possible to miniaturize the heat pump apparatus.

Further, since the heat transfer in the radiator 42 is accelerated, the temperature of the refrigerant is lowered at an outlet of the radiator 42 and cooling capacity of the evaporator 44 is increased, whereby energy conservation can be realized. Moreover, since the refrigerant is brought into a near-critical refrigeration cycle which can be brought into the supercritical state on the radiation side of the drying apparatus and the temperature of the refrigerant is lowered at the outlet of the radiator 42, this results in the effect that it is possible to improve the refrigeration cycle COP largely, whereby it is possible to realize energy conservation further.

Next, FIGS. 4(a) and 4(b) show a cross-sectional view and an enlarged view of a main portion of a fin constituting an evaporator of a drying apparatus according to another embodiment of the present invention, respectively. As shown in FIG. 4, a fin 55 constituting the evaporator is a corrugated fin provided with folded portions 56. The ridgeline direction of the folded portions 56 is substantially the direction of gravity. Since the folded portions 56 are formed in the direction of gravity of the fin 55 in this manner, drain water generated and condensed by dehumidifying the drying air on the surface of the fin 55 of the evaporator 44 is concentrated on the troughs 57 of the folded portions 56 to form droplets 47. Since the droplets 47 are formed by concentrating the drain water on the troughs 57 in this way, there is no instability of places where the droplets 47 are formed. By uniformly forming the troughs 57 over the evaporator 44 on which the droplets 47 are formed, since the droplets 47 drop into the radiator 42 uniformly, a liquid film of the drain water is formed over the radiator 42 uniformly. Thus, sensible heat exchange with the drying air and latent heat exchange with the drain water are carried out in the radiator 42, thereby accelerating heat transfer. As a result, since the amount of heat exchange is increased and heat transfer to the refrigerant that flows inside the radiator 42 is accelerated, it is possible to further miniaturize the size of the radiator 42. Therefore, it is possible to miniaturize the heat pump apparatus.

Further, in the present embodiment, in comparison with the saw-toothed structure is formed on the lower end surface in the direction of gravity of the fin, it is possible to increase a heat transfer area of the fin extremely. For this reason, it is possible to improve the ability of heat transfer of the evaporator. As a result, since the drying apparatus has the effect that it is possible to improve the refrigeration cycle COP largely as well as ability to dehumidify drying air can be improved, it is possible to realize energy conservation further.

Third Embodiment

Hereinafter, a third embodiment of the present invention will now be described with reference to the drawing.

FIG. 5 is a block diagram of a drying apparatus according to a third embodiment of the present invention. In FIG. 5, common constituent elements shown in FIG. 1 are designated with the same reference numbers, and explanation thereof will be omitted. A reference number 31 represents a compressor, a reference number 62 represents a radiator, a reference number 33 represents an expansion valve (expansion mechanism), and a reference number 64 represents an evaporator. A heat pump apparatus is constructed by connecting these constituent elements to one another in this order through pipes and charging a refrigerant thereinto. As the refrigerant, a CO₂ refrigerant which can be brought into the supercritical state on the radiation side is charged thereinto. Difference between the first and third embodiments is a point that drain water condensed and generated by dehumidifying drying air in the evaporator 64 is received by a pan for drain water 65, the drain water collected in the drain water pan 65 is drawn by a pump 66, and a spray mechanism 67 is provided to spray the drain water into the radiator 62.

In FIG. 5, solid arrows indicate the flow of the refrigerant, hollow arrows indicate the flow of the drying air, and a hollow arrow with diagonal lines indicates the flow of outside air. The drying apparatus is constituted so that the drying air flows from the lower side of the subject 36 to be dried to the radiator 62 through the evaporator 64 in this order. Namely, the evaporator 64 is provided at the windward side of the radiator 62 and under the radiator 62.

Next, an operation of the drying apparatus of the third embodiment will be described. The refrigerant is compressed by the compressor 31 and brought into a high temperature and high pressure state. The refrigerant is heat-exchanged in the radiator 62 with drying air received from the evaporator 64, and the refrigerant heats the drying air. This makes the refrigerant cooled. The refrigerant is then decompressed by the expansion mechanism 33, and is brought into a low temperature and low pressure state. The refrigerant is heat-exchanged with the drying air which passes through the subject 36 by the evaporator 64, thereby cooling the drying air. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and the refrigerant is again sucked into the compressor 31. Therefore, the drying air cooled and dehumidified by the evaporator 64 is heated by the radiator 62, and is then brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state removes moisture or water from the subject 36 and is brought into a humid state when the drying air is forcibly brought into contact with the subject 36 by the blower fan 37. After the temperature of the drying air is lowered by heat-exchanging it with the outside air in the heat exchanger 38, the drying air is again cooled and dehumidified by the evaporator 64.

By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 36.

In the present embodiment, the drying apparatus has a structure in which the drain water condensed and generated by dehumidifying drying air in the evaporator 64 is received by a pan for drain water 65, the drain water collected in the drain water pan 65 is drawn by a pump 66, and a spray mechanism 67 is provided to spray the drain water into the radiator 62. Thus, it is possible to spray the specific amount of drain water over the radiator 62 stably and uniformly. For this reason, a liquid film of the drain water is formed over the radiator 62 uniformly. Thus, sensible heat exchange with the drying air and latent heat exchange with the drain water are carried out in the radiator 62, thereby accelerating heat transfer. As a result, since the amount of heat exchange In the radiator 62 is increased and heat transfer to the refrigerant that flows to the inside of the radiator 62 is accelerated, it is possible to further miniaturize the size of the radiator 62. Therefore, it is possible to miniaturize the heat pump apparatus.

Further, since the heat transfer in the radiator 62 is accelerated, the temperature of the refrigerant is lowered at an outlet of the radiator 62 and cooling capacity of the evaporator 64 is increased, whereby energy conservation can be realized. Moreover, since the refrigerant is brought into a near-critical refrigeration cycle which can be brought into the supercritical state on the radiation side of the drying apparatus and the temperature of the refrigerant is lowered at the outlet of the radiator 62, this results in the effect that it is possible to improve the refrigeration cycle COP largely, whereby it is possible to realize energy conservation further.

In this regard, it should be noted that although the drain water condensed and generated by dehumidifying the drying air in the evaporator 64 is supplied to the radiator 62 by the pump 66, the same effect can be obtained even if no drain water but water supplied from the outside thereof is used.

Further, the drying apparatus has a structure in which moisture or water is removed from the subject 36 to dry it by forcibly running the drying air from an upper side to a lower side with respect to the subject 36 so that the drying air is brought into contact with the subject 36. Thus, the drying apparatus has a feature that it is easy to apply heat pump type drying apparatus to a vertical washer-dryer.

In this regard, the structure in which the drying air is forcibly run from an upper side to a lower side with respect to the subject 36 has been described in the present embodiment, but the structure is not limited thereto. It should be noted that even though the drying apparatus has a structure in which the drying air is forcibly run from a lower side to an upper side with respect to the subject 36 as well as the first and second embodiments, the same effect can be obtained in case of supplying the drain water condensed and generated in the evaporator 64 to the radiator 62 by means of the pump 66.

Fourth Embodiment

FIG. 6 is a block diagram of a drying apparatus according to a fourth embodiment of the present invention. In the drying apparatus of the fourth embodiment shown in FIG. 6, a heat pump apparatus is constructed from a compressor 1, a radiator 2, a throttle apparatus 3 and an evaporator 4 connected to each other in this order via pipes through which a refrigerant is circulated as indicated by solid arrows. Further, the drying apparatus is provided with a dry room 5, a circulation duct 6, a blower fan 7, a sprinkler mechanism 8, a pan for drain water 9 and a moisture collection mechanism 10.

The drying apparatus has a structure in which the drying air that circulates as indicated by hollow arrows M is delivered by means of the blower fan 7 to enter the circulation duct 6 from a lower side of the dry room 5, and then, the drying air passes through the evaporator 4 and the radiator 2 in this order to flow toward an upper side of the dry room 5. Namely, the evaporator 4 is provided at the windward side of the radiator 2 and under the radiator 2.

Further, the sprinkler mechanism 8 for supplying water from the outside through the pipes is provided at the leeward side of the radiator 2 and above the radiator 2 in the direction of gravity. Moreover, the drain water pan 9 is provided at the windward side of the evaporator 4 and under the evaporator 4 in the direction of gravity. Furthermore, the drying apparatus has a structure in which the moisture collection mechanism 10 is provided between the radiator 2 and the evaporator 4.

Next, an operation of the drying apparatus having the structure described above will be described.

When the heat pump apparatus starts to operate, the refrigerant becomes a high temperature and high pressure state by being compressed by the compressor 1, and is heat-exchanged with the drying air got out of the evaporator 4 in the radiator 2, whereby the refrigerant is cooled by heating the drying air. The refrigerant is then decompressed by the throttle apparatus 3, and is brought into a low temperature and low pressure state. The refrigerant is heat-exchanged with the drying air which passes through the subject 16 by the evaporator 4, thereby cooling the drying air. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and the refrigerant is again sucked into the compressor 31.

On the other hand, the drying air cooled and dehumidified by the evaporator 4 is heated by the radiator 2, and is then brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state is delivered to the dry room 5 by the blower fan 7, and forcibly brought into contact with the subject 16. At this time, the drying air is brought into a humid state by removing moisture or water from the subject 16 and is again cooled and dehumidified by the evaporator 4. By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 16 entered into the inside of the dry room 5.

Further, the sprinkler mechanism 8 drops or sprays water into the radiator 2 from the upper side thereof. Moreover, the drain water pan 9 receives the drain water dropped from the evaporator 4 to discharge the drain water collected in the drain water pan 9 to the outside of the drying apparatus. Furthermore, the moisture collection mechanism 10 brings the drying air between the radiator 2 and the evaporator 4 into contact with the low temperature outside air to collect moisture or water included in the drying air.

In the drying apparatus of the present embodiment, the drying apparatus has a structure in which the water Is dropped or sprayed into the radiator 2 using the sprinkler mechanism 8. Thus, it is possible to sprinkle (or spray) the specific amount of water over the radiator 2 stably and uniformly. For this reason, a liquid film of the water is formed over the radiator 2 uniformly. Namely, sensible heat exchange with the drying air and latent heat exchange with the water are carried out in the radiator 2, thereby accelerating heat transfer. As a result, since the amount of heat exchange in the radiator 2 is increased and heat transfer to the refrigerant that flows to the inside of the radiator 2 is accelerated, it is possible to further miniaturize the size of the radiator 2. Therefore, it is possible to miniaturize the heat pump apparatus.

Further, the moisture or water condensed and generated by cooling and dehumidifying the drying air in the evaporator 4 drops on the drain water pan 9 to be discharged to the outside. By condensing the moisture or water in the drying air at the leeward side of the evaporator 4 by means of the moisture collection mechanism 10 provided at the position where the moisture or water is brought into contact with the low temperature outside air and discharging it to the outside, it is possible to accelerate the removal of the moisture or water included in the subject 16. Moreover, the moisture collection mechanism 10 may have a structure in which the moisture or water is not only brought into contact with the outside air, but also is forcibly cooled by a fan or the like, whereby it is possible to further accelerate the drying of the subject 16.

Further, since the heat transfer in the radiator 2 is accelerated, the temperature of the refrigerant is lowered at an outlet of the radiator 2 and cooling capacity of the evaporator 4 is increased, whereby energy conservation can be realized. Moreover, since the refrigerant is brought into a near-critical refrigeration cycle which can be brought into the supercritical state on the radiation side of the refrigerant and the temperature of the refrigerant is lowered at the outlet of the radiator 2, this results in the effect that it is possible to improve the refrigeration cycle COP largely, whereby it is possible to realize energy conservation further.

Further, the drying apparatus has a structure in which moisture or water is removed from the subject 16 to dry it by forcibly running the drying air from an upper side to a lower side with respect to the subject 16 so that the drying air is brought into contact with the subject 16. Thus, the drying apparatus has a feature that it is easy to apply heat pump type drying apparatus to a vertical washer-dryer.

Fifth Embodiment

Hereinafter, a fifth embodiment of the present invention will now be described with reference to the drawing. FIG. 7 is a block diagram of a drying apparatus according to a fifth embodiment of the present invention. In the fifth embodiment shown in FIG. 7, common constituent elements shown in the fourth embodiment of FIG. 6 are designated with the same reference numbers, and explanation thereof will be omitted.

The structure of the drying apparatus of the fifth embodiment is different from the structure of the fourth embodiment in the presence of a sprinkler mechanism 8a in which the drain water collected in the drain water pan 9 is pumped up by a pump 14 to supply it to the sprinkler mechanism 8a through a pipe to drop or spray it into the radiator 2.

In the drying apparatus of the present embodiment, since the low temperature drain water condensed and generated in the evaporator 4 is dropped or sprayed into the radiator 2, it is possible to reduce the pressure at the high pressure side of the heat pump apparatus by carrying out latent heat exchange with a larger difference of temperature from the refrigerant temperature in the radiator 2. Therefore, it is possible to reduce power requirement of the compressor 1, that is, to realize energy conservation of the heat pump apparatus.

Sixth Embodiment

Hereinafter, a sixth embodiment of the present invention will now be described with reference to the drawing. FIG. 8 is a block diagram of a drying apparatus according to a sixth embodiment of the present invention. In the sixth embodiment shown in FIG. 8, common constituent elements shown in the fourth embodiment of FIG. 6 are designated with the same reference numbers, and explanation thereof will be omitted.

The structure of the drying apparatus of the sixth embodiment is different from the structure of the fourth embodiment in the ways of the structure for circulating the drying air and a sprinkler mechanism.

Namely, the drying apparatus of the present embodiment has a structure in which the drying air is delivered by means of the blower fan 7 to enter the circulation duct 6 from an upper side of the dry room 5, and then, the drying air passes through the evaporator 4 and the radiator 2 in this order to run In circle toward a lower side of the dry room 5.

The sprinkler mechanism is constructed so that the evaporator 4 is provided at the windward side of the radiator 2 and above the radiator 2 in the direction of gravity, and the drain water generated by dehumidification due to the evaporator 4 is dropped into the radiator 2 by its gravity or the force of wind. Further, the drain water pan 9 is constructed so that the drain water pan 9 is provided at the leeward side of the radiator 2 and under the radiator 2 in the direction of gravity, and the drain water that is dropped from the evaporator 4 and passed through the radiator 2 is collected in the drain water pan 9.

Next, an operation of the drying apparatus having the structure described above will be described.

When the heat pump apparatus starts to operate, the refrigerant becomes a high temperature and high pressure state by being compressed by the compressor 1, and is heat-exchanged with the drying air got out of the evaporator 4 in the radiator 2, whereby the refrigerant is cooled by heating the drying air. The refrigerant is then decompressed by the throttle apparatus 3, and is brought into a low temperature and low pressure state. The refrigerant is heat-exchanged with the drying air which passes through the subject 16 by the evaporator 4, thereby cooling the drying air. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and the refrigerant is again sucked into the compressor 1.

On the other hand, the drying air cooled and dehumidified by the evaporator 4 is heated by the radiator 2, and is then brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state is delivered to the dry room 5 by the blower fan 7, and forcibly brought into contact with the subject 16. At this time, the drying air is brought into a humid state by removing moisture or water from the subject 16 and is again cooled and dehumidified by the evaporator 4. By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 16 entered into the inside of the dry room 5.

Further, the drain water generated in the evaporator 4 is dropped into the radiator 2 from the upper side thereof with its gravity or the like by means of the sprinkler mechanism. Moreover, the drain water collected in the drain water pan 9 is discharged to the outside of the drying apparatus. Furthermore, in the same manner as the fourth embodiment, the moisture collection mechanism 10 carries out the operation that the drying air flowing between the radiator 2 and the evaporator 4 is brought into contact with the low temperature outside air to collect moisture or water included in the drying air.

In the drying apparatus of the present embodiment, the refrigerant is heat-exchanged with the humid drying air which passes through the subject 16 by the evaporator 4, thereby cooling the drying air. The moisture or water included in the drying air is condensed on the surface of a fin of the evaporator 4, and resulting drain water is dropped into the radiator 2 using gravity thereof and shearing force due to blowing. Since the drying apparatus of the present embodiment has a structure described above, sensible heat exchange with the drying air and latent heat exchange with the drain water are carried out in the radiator 2, thereby accelerating heat transfer. As a result, since the amount of heat exchange at the radiator 2 is increased and heat transfer to the refrigerant that flows inside the radiator 2 is accelerated, it is possible to miniaturize the size of the radiator 2 to the same level as the size of the evaporator 4.

Further, in comparison with the fourth or fifth embodiment, since it is possible to bring the water into contact with the radiator 2 only by gravity thereof and shearing force due to blowing without supply of water and pumping power, it is possible to miniaturize the drying apparatus and to realize energy conservation.

In this regard, it should be noted that although the expansion valve is used as the throttle apparatus 3 in any one of the fourth to sixth embodiments, the same effect can be obtained even if a capillary tube is used as the throttle apparatus 3.

Further, although the sprinkler mechanism having the structure in which the drain water generated in the evaporator 4 is used has been described in the sixth embodiment, this structure is not limited thereto. It should be noted that the same effect can be achieved even in the case of a sprinkler mechanism having a structure in which supply of water from the outside or pumping power is used as well as the fourth and fifth embodiments.

Seventh Embodiment

Hereinafter, a seventh embodiment of the present invention will now be described with reference to the drawing. FIG. 9 is a block diagram of a drying apparatus according to a seventh embodiment of the present invention. In the seventh embodiment shown in FIG. 9, common constituent elements shown in the sixth embodiment of FIG. 8 are designated with the same reference numbers, and explanation thereof will be omitted.

The structure of the drying apparatus of the seventh embodiment is different from the structure of the sixth embodiment in the way that the drying apparatus is provided with first and second evaporators 4a and 4b, first and second circulation ducts 6a and 6b, and first and second pans for drain water 9a and 9b.

Namely, the drying apparatus of the present embodiment has a structure in which the drying air is delivered by means of the blower fan 7 to enter the first circulation duct 6a from the upper side of the dry room 5 and passes through the first evaporator 4a, and then, the drying air enters the second circulation duct 6b and passes through the second evaporator 4b and the radiator 2 in this order to run in circle toward a lower side of the dry room 5.

Further, the first evaporator 4a is provided at the windward side of the second evaporator 4b.

Moreover, the drainage mechanism is constructed so that the first drain water pan 9a is provided at the leeward side of the first evaporator 4a and under the first evaporator 4a in the direction of gravity, and the drain water generated by dehumidification due to the first evaporator 4a is received by the first drain water pan 9a to discharge the collected drain water to the outside of the drying apparatus.

The sprinkler mechanism is constructed so that the second evaporator 4b is provided at the windward side of the radiator 2 and above the radiator 2 in the direction of gravity, and the drain water generated by dehumidification due to the second evaporator 4b is dropped into the radiator 2 by its gravity or the force of wind.

Further, the second drain water pan 9b is constructed so that the second drain water pan 9b is provided at the leeward side of the radiator 2 and under the radiator 2 in the direction of gravity, and the drain water that is dropped from the second evaporator 4b and passed through the radiator 2 is collected in the second drain water pan 9b.

Next, an operation of the drying apparatus having the structure described above will be described.

When the heat pump apparatus starts to operate, the refrigerant becomes a high temperature and high pressure state by being compressed by the compressor 1, and is heat-exchanged with the drying air got out of the second evaporator 4b in the radiator 2, whereby the refrigerant is cooled by heating the drying air. The refrigerant is then decompressed by the throttle apparatus 3 to be brought into a low temperature and low pressure state. The refrigerant is heat-exchanged with the drying air which passes through the subject 16 by the first and second evaporators 4a and 4b, thereby cooling the drying air. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and the refrigerant is again sucked into the compressor 1.

On the other hand, the drying air cooled and dehumidified by the first and second evaporators 4a and 4b is heated by the radiator 2, and is then brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state is delivered to the dry room 5 by the blower fan 7, and forcibly brought into contact with the subject 16. At this time, the drying air is brought into a humid state by removing moisture or water from the subject 16 and is again cooled and dehumidified by the first and second evaporators 4a and 4b. By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 16 entered into the inside of the dry room 5.

Further, the drain water generated in the second evaporator 4b is dropped into the radiator 2 from the upper side thereof with its gravity or the like by means of the sprinkler mechanism. Moreover, the drain water collected in the second drain water pan 9b is discharged to the outside of the drying apparatus. Furthermore, in the same manner as the fifth embodiment, the moisture collection mechanism 10 carries out the operation that the drying air flowing between the second evaporator 4b and the radiator 2 is brought into contact with the low temperature outside air to collect moisture or water included in the drying air.

In the drying apparatus of the present embodiment, the first drain water pan 9a is provided under the first evaporator 4a, and the radiator 2 is provided under the second evaporator 4b. By having this structure, the humid drying air which passes through the subject 16 is heat-exchanged with the first evaporator 4a, and the moisture or water condensed and generated by the first evaporator 4a is dropped on the first drain water pan 9a to be discharged to the outside of the drying apparatus. The drying air after heat exchange with the first evaporator 4a is heat-exchanged with the second evaporator 4b. By dropping the moisture or water condensed and generated by the second evaporator 4b into the radiator 2, sensible heat exchange with the drying air and latent heat exchange with the drain water are carried out in the radiator 2, thereby accelerating heat transfer. As a result, since the amount of heat exchange at the radiator 2 is increased and heat transfer to the refrigerant that flows inside the radiator 2 is accelerated, it is possible to miniaturize the size of the radiator 2 to the same level as the size of the evaporator.

In addition, by dividing the evaporator into the first and second evaporators 4a and 4b in this manner, it is possible to surely discharge the moisture or water condensed and generated in the first evaporator 4a to the outside from the first drain water pan 9a. Therefore, since it is possible to collect the moisture or water that cannot be condensed by the moisture collection mechanism 10 perfectly more surely than the sixth embodiment, it is possible to shorten the time required to remove the moisture or water from the subject 16 and to realize energy conservation further.

Eighth Embodiment

Hereinafter, an eighth embodiment of the present invention will now be described with reference to the drawing. FIG. 10 is a block diagram of a drying apparatus according to an eighth embodiment of the present invention. In the eighth embodiment shown in FIG. 10, common constituent elements shown in the seventh embodiment of FIG. 9 are designated with the same reference numbers, and explanation thereof will be omitted.

The structure of the drying apparatus of the eighth embodiment is different from the structure of the seventh embodiment in the way that the drying apparatus is provided with a bypass circuit.

Namely, the bypass circuit is constructed from a three-way valve 12 provided between the first evaporator 4a and the second evaporator 4b and a bypass pipe 13 that connects the three-way valve 12 to the inlet of the compressor 1.

Next, an operation of the drying apparatus having the structure described above will be described.

When the heat pump apparatus starts to operate, the refrigerant becomes a high temperature and high pressure state by being compressed by the compressor 1, and is heat-exchanged with the drying air got out of the second evaporator 4b in the radiator 2, whereby the refrigerant is cooled by heating the drying air. The refrigerant is then decompressed by the throttle apparatus 3 to be brought into a low temperature and low pressure state. Further, after the refrigerant is heat-exchanged with the drying air which passes through the subject 16 by the first evaporator 4a to be heated, the refrigerant is delivered toward the A direction by the three-way valve 12. Then, the refrigerant flows into the second evaporator 4b and is heat-exchanged with the drying air again. Moisture or water included in the drying air is condensed and dehumidified, thereby heating the refrigerant, and, the refrigerant is sucked into the compressor 1.

On the other hand, the drying air cooled and dehumidified by the first and second evaporators 4a and 4b is heated by the radiator 2, and is then brought into a high temperature and low moisture state. The drying air brought into the high temperature and low moisture state is delivered to the dry room 5 by the blower fan 7, and forcibly brought into contact with the subject 16. At this time, the drying air is brought into a humid state by removing moisture or water from the subject 16 and is again cooled and dehumidified by the first and second evaporators 4a and 4b.

Further, by controlling the three-way valve 12 so as to switch to the B direction after T minutes (for example, 60 minutes) elapses from the start time of operation of the heat pump, the refrigerant is heat-exchanged with the first evaporator 4a and delivered toward the bypass pipe 13, and the refrigerant is then sucked into the compressor 1. Therefore, since the refrigerant is delivered to the second evaporator 4b, drain water is not dropped into the radiator 2, whereby it is possible to prevent moisture or water from being reevaporated in the radiator 2. By repeating the operation described above, it is possible to carry out the drying operation for removing moisture or water from the subject 16 entered into the inside of the dry room 5.

In the drying apparatus of the present embodiment, the bypass circuit constructed from the three-way valve 12 and the bypass pipe 13 is provided, and by switching the flow direction of the refrigerant with the bypass circuit, it is possible to prevent moisture or water from being reevaporated in the radiator 2 after predetermined amount of time elapses from the start time of operation of the heat pump. Therefore, it is possible to carry out removal of moisture or water from the subject 16 surely.

In this regard, in the drying apparatus of any one of the first to fifth embodiments described above, the structure (drawings and descriptions are omitted) in which the temperature of the refrigerant run into the radiator 2 of the heat pump apparatus is set to the temperature of boiling water or more may be adopted. According to the present structure, it is possible to heat the temperature of the drain water which drops into the radiator 2 to the temperature of boiling water (that is, 100° C.) or more. Further, by heating the radiator, the heat exchanger of the evaporator, the air circulation duct, a washing drum and the like with high temperature air after the termination of the drying operation before which clothes are removed from the drying apparatus, it is possible to prevent mold from getting on the inside of the drying apparatus.

Ninth Embodiment

Hereinafter, a ninth embodiment of the present invention will now be described with reference to FIGS. 11 and 12. FIG. 11 is a drawing which shows temperature changes In refrigerant and air in the radiator of a drying apparatus according to a ninth embodiment of the present invention in the case of using a refrigerant (for example, CO₂) in which the pressure at the high pressure side can be brought into the supercritical state in the heat pump apparatus of any one of the fourth to ninth embodiments. FIG. 12 is a drawing which shows temperature changes in refrigerant and air in the radiator of the drying apparatus in case of using a CFC refrigerant.

Namely, as shown in FIG. 12, in the case of the CFC refrigerant, the refrigerant is heat-exchanged with the air in the radiator 2 so as to state-change from a superheated state to a supercooled state through a gas-liquid two-phase state, whereby the temperature at the air outlet of the radiator 2 rises to the point C.

On the other hand, in the case of a refrigerant such as CO₂ in which the pressure at the high pressure side can be brought into the supercritical state and heat exchange in the radiator 2 can be carried out at the supercritical state, as shown in FIG. 11, the heat exchange is carried out without phase change of the refrigerant in the radiator 2. Thus, it is possible to reduce the temperature difference ΔT between the temperature at the air outlet and the temperature at the refrigerant inlet in comparison with the temperature difference ΔT in the case of using the CFC refrigerant, whereby the temperature at the air outlet of the radiator 2 becomes the point D. Namely, if the temperatures T₀ at the refrigerant inlet in both cases are the same, the temperature D at the air outlet in the case of using the CO₂ refrigerant can be heightened in comparison with the temperature C at the air outlet in the case of using the CFC refrigerant. Therefore, since the temperature of the drying air brought into contact with the subject 16 becomes high, the ability to remove moisture or water from the subject 16 can be increased, and this makes it possible to carry out the drying operation in a short time.

In the drying apparatus of the ninth embodiment, by operating the drying apparatus so that the pressure at the high pressure side of the heat pump apparatus becomes supercritical pressure, it is possible to heighten the temperature of the drying air further. Therefore, it is possible to shorten the drying time, and the operation of the drying apparatus can be carried out with high efficiency.

In this regard, the drying apparatus explained in any one of the embodiments described above can be utilized for a drying apparatus for tableware, a drying apparatus for garbage disposal or the like in addition to a drying apparatus for clothes or a bathroom.

INDUSTRIAL APPLICABILITY

As is clear from the above description, according to the drying apparatus of the present invention, since the drying apparatus has a structure in which the water is dropped or sprayed into the radiator using the sprinkler mechanism, sensible heat exchange with the drying air and latent heat exchange with the water are carried out in the radiator. As a result, since the amount of heat exchange in the radiator is increased and heat transfer to the refrigerant that flows to the inside of the radiator is accelerated, it is possible to further miniaturize the size of the radiator, and this makes it possible to miniaturize the heat pump apparatus. Further, since heat transfer to the refrigerant that flows to the inside of the radiator is accelerated, the temperature of the refrigerant is lowered at the outlet of the radiator and cooling capacity of the evaporator is increased in the case of using a refrigerant which can be brought into the supercritical state on the radiation side of a refrigeration cycle such as CO₂ as a refrigerant. Therefore, it is possible to realize the heat pump type drying apparatus with high efficiency further.

Further, according to the drying apparatus of the present invention, since the low temperature drain water condensed and generated in the evaporator is dropped or sprayed into the radiator, it is possible to reduce the pressure at the high pressure side of the heat pump apparatus by carrying out latent heat exchange with a larger difference of temperature from the refrigerant temperature in the radiator. Therefore, it is possible to reduce power requirement of the compressor, that is, to realize energy conservation of the heat pump apparatus.

Moreover, according to the drying apparatus of the present invention, by taking the structure in which the drain water condensed and generated in the evaporator is dropped into the radiator using gravity thereof and shearing force due to blowing, since it is possible to bring the water into contact with the radiator only by gravity thereof and shearing force due to blowing without supply of water and pumping power, it is possible to realize energy conservation further.

Furthermore, according to the drying apparatus of the present invention, by dividing the evaporator into the first and second evaporators, it is possible to surely discharge the moisture or water condensed and generated in the first evaporator to the outside from the drain water pan. Therefore, since it is possible to collect the moisture or water that cannot be condensed by the moisture collection mechanism perfectly more surely, it is possible to shorten the time required to remove the moisture or water from the subject and to realize energy conservation further.

Further, according to the drying apparatus of the present invention, the three-way valve is provided between the first and second evaporators, and by switching the flow direction of the refrigerant with the three-way valve, it is possible to prevent moisture or water from being reevaporated in the radiator after predetermined amount of time from the start time of operation of the heat pump. Therefore, it is possible to carry out removal of moisture or water from the subject surely.

Moreover, according to the drying apparatus of the present invention, since the temperature of the drain water that drops into the radiator is heated by heating the refrigerant that flows in the radiator to the temperature of boiling water or more, it is possible to prevent or reduce growth of mold or the like that gets on the fin of the radiator.

Furthermore, according to the drying apparatus of the present invention, by operating the drying apparatus so that the pressure at the high pressure side of the heat pump apparatus becomes supercritical pressure, it is possible to heighten the temperature of the drying air further. Therefore, it is possible to shorten the drying time further, and the operation of the drying apparatus can be carried out with high efficiency.

Claims

1. A drying apparatus comprising:

a heat pump apparatus having a compressor, a radiator, a throttle apparatus and an evaporator connected in this order via pipes through which a refrigerant is circulated;

a dry room wherein air heated in the radiator is introduced into the dry room, the air dried in the dry room is dehumidified by the evaporator, and the air dehumidified in the evaporator is reheated in the radiator; and

a sprinkler mechanism for dropping or spraying water into the radiator.

2. The drying apparatus according to claim 1, wherein the sprinkler mechanism drops or sprays drain water generated by dehumidifying the air in the evaporator.

3. The drying apparatus according to claim 1, further comprising a moisture collection mechanism for collecting moisture or water included in the air between the evaporator and the radiator.

4. The drying apparatus according to claim 1, further comprising a pump, wherein the evaporator and the radiator are respectively constituted from a heat transfer tube and a fin, and wherein drain water generated by dehumidifying the air in the evaporator is drawn by the pump and the sprinkler mechanism drops or sprays the drain water into the radiator.

5. A drying apparatus comprising:

a heat pump apparatus having a compressor, a radiator, a throttle apparatus and an evaporator connected in this order via pipes through which a refrigerant is circulated, the evaporator being provided above the radiator;

a dry room wherein air heated in the radiator is introduced into the dry room, the air dried in the dry room is dehumidified by the evaporator, and the air dehumidified in the evaporator is reheated in the radiator, drain water being generated by dehumidifying the air in the evaporator: and a sprinkler mechanism for dropping or spraying the drain water into the radiator.

6. The drying apparatus according to claim 5, wherein the sprinkler mechanism drops the drain water into the radiator by means of gravity of the drain water or force of wind.

7. The drying apparatus according to claim 6, wherein the evaporator includes a fin having a lower end surface with respect to the direction of gravity, the lower end surface having a saw-toothed structure.

8. The drying apparatus according to claim 5, wherein the evaporator includes a fin having a fin base, the fin being a corrugated fin in which the fin base is folded.

9. The drying apparatus according to claim 5, further comprising a pump, wherein the evaporator and the radiator are respectively constituted from a heat transfer tube and a fin, and wherein drain water generated by dehumidifying the air in the evaporator is drawn by the pump and the sprinkler mechanism drops or sprays the drain water into the radiator.

10. The drying apparatus according to claim 5, further comprising a moisture collection mechanism for collecting moisture or water included in the air between the evaporator and the radiator.

11. A drying apparatus comprising:

a heat pump apparatus having a compressor, a radiator, a throttle apparatus, a first evaporator and a second evaporator connected in this order via pipes through which a refrigerant is circulated;

a dry room wherein air heated in the radiator is introduced into the dry room, the air dried in the dry room is dehumidified by the first and second evaporators, and the air dehumidified in the first and second evaporators is reheated in the radiator;

a drainage mechanism for draining drain water generated by dehumidifying the air in the first evaporator; and

a sprinkler mechanism for dropping or spraying drain water generated by dehumidifying the air in the second evaporator into the radiator.

12. The drying apparatus according to claim 11, further comprising a moisture collection mechanism for collecting moisture or water included in the air between the second evaporator and the radiator.

13. The drying apparatus according to claim 11, wherein the heat pump apparatus further has a bypass circuit through which the refrigerant bypasses the second evaporator.

14. The drying apparatus according to any one of claim 1, 5 or 11, wherein the heat pump apparatus sets the temperature of the refrigerant run into the radiator to the temperature of boiling water or more.

15. The drying apparatus according to any one of claim 1, 5 or 11 wherein the heat pump apparatus has a high pressure side and is constructed to operate so that the pressure of the high pressure side thereof becomes supercritical pressure.

16. The drying apparatus according to any one of claim 1, 5 or 11 wherein a refrigerant in which the pressure at the high pressure side of the heat pump apparatus becomes supercritical pressure is used as the refrigerant.

17. The drying apparatus according to claim 1, further comprising: a circulation duct; and a radiation mechanism which radiates the quantity of heat of the drying air outside the circulation duct.

18. The drying apparatus according to claim 17, wherein the radiation mechanism is a heat exchanger for roughly drawing from drying air, the radiation mechanism being provided across the inside and outside of the circulation duct.

19. The drying apparatus according to claim 5, further comprising; a circulation duct; and a radiation mechanism which radiates the quantity of heat of the drying air outside the circulation duct.

20. The drying apparatus according to claim 19, wherein the radiation mechanism is a heat exchanger for roughly drawing from drying air, the radiation mechanism being provided across the inside and outside of the circulation duct.