ELECTRIC FAN

The present invention provides an electric fan capable of blowing cool wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter. The electric fan of the present invention comprises: a housing having a suction port for air and a blowing port for air; an axial flow fan for suctioning air from the suction port into the housing and for blowing the suctioned air from the blowing port; an evaporation filter for passing the air suctioned from the suction port; a water supplying system capable of supplying water to the evaporation filter; an indirect heat exchanger for cooling the air passed through the evaporation filter, the indirect heat exchanger being disposed downstream from the evaporation filter; and a cooler for cooling a coolant for the indirect heat exchanger; wherein the suction port and the blowing port are formed on the same side surface of the housing; and wherein the blowing port is formed on the central part of the side surface of the housing, and the suction port is formed on the outer edge part of the blowing port.

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Description
FIELD OF THE INVENTION

The present invention relates to an electric fan for blowing cool wind by utilizing vaporization heat of water contained in an evaporation filter.

BACKGROUND ART

Although electric fans simply create a flow of air, the created flow of air blows off air heated on a surface of a person's human body, and thereby the person feels that the air from the electric fan is cool. However, since the electric fan basically does not have a function of decreasing the temperature of air, when the temperature of the air is too high, the person no longer feels that the air is cool.

Therefore, an electric fan blowing cool wind by utilizing the vaporization heat of water to actively decrease the temperature of air, which is referred to as a cool wind fan, is used. More specifically, an evaporation filter is disposed in a path of air, and water is supplied to the evaporation filter. When the air passes through the evaporation filter containing water, the water contained in the evaporation filter is evaporated, and the air is deprived of the vaporization heat required for the vaporization of water, whereby the air is cooled.

In this kind of the cool wind fan, the water supplied beyond the water-retaining capacity of the evaporation filter falls from the evaporation filter into a tank, which results in making unpleasant sound continuously. Patent Documents 1 and 2 disclose methods for preventing the unpleasant sound.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP 05-93525 A

Patent Document 2: JP 2008-138932 A

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, when the electric fan is a large flow rate fan having a large blade diameter, which is used in a wide space such as a gymnasium, a factory, and a warehouse, or used for outdoor space, warm air is not sufficiently cooled and the warm air may still be blown even if the vaporization heat of water is utilized.

Accordingly, an object of the present invention is to provide an electric fan capable of blowing cool wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter.

Means for Solving the Problems

An electric fan according to the present invention comprises:

a housing having a suction port for air and a blowing port for air;

an axial flow fan for suctioning air from the suction port into the housing and for blowing the suctioned air from the blowing port;

an evaporation filter for passing the air suctioned from the suction port;

a water supplying system capable of supplying water to the evaporation filter;

an indirect heat exchanger for cooling the air passed through the evaporation filter, the indirect heat exchanger being disposed downstream from the evaporation filter; and

a cooler for cooling a coolant for the indirect heat exchanger;

wherein the suction port and the blowing port are formed on the same side surface of the housing; and

wherein the blowing port is formed on the central part of the side surface of the housing, and the suction port is formed on the outer edge part of the blowing port.

Effect of the Invention

The present invention can provide an electric fan capable of blowing cool wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing an inner structure of an electric fan according to one embodiment of the present invention.

FIG. 2 is a front view showing an appearance of an electric fan according to one embodiment of the present invention.

FIG. 3 is a side view showing an appearance of an electric fan according to one embodiment of the present invention.

FIG. 4 is a back view showing an appearance of an electric fan according to one embodiment of the present invention.

FIG. 5 is an enlarged view showing a configuration of a hot wind discharger.

 MODE FOR CARRYING OUT THE INVENTION

The electric fan of the present invention is an electric fan blowing cool wind by utilizing the vaporization heat of water contained in an evaporation filter. The electric fan of the present invention can blow cool wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter. The inner structure of the electric fan according to one embodiment of the present invention is shown in FIG. 1, and the appearance of the electric fan according to one embodiment of the present invention is shown in FIGS. 2 to 4. In this electric fan, a suction port 11 for air and a blowing port 12 for air are formed on the front part of a housing 10, and an axial flow fan 20 is mounted inside the housing 10.

The housing 10 may be made from a plastic or may be made from a fiber-reinforced plastic (FRP). At least the inner surface of the housing 10 is preferably made from a heat insulating material such as a plastic foam in terms of the prevention of the temperature increase inside the housing 10 due to the ambient temperature. The position of the suction port 11 and the blowing port 12 on the housing 10 can be suitably selected depending on the purpose. For example, the suction port 11 can be formed on one side surface of the housing 10, and the blowing port 12 can be formed on the opposed side surface of the housing 10. However, in this case, warm air before cooling is continuously suctioned from the suction port 11. In particular, for a large flow rate fan having a large blade diameter, the warm air is not sufficiently cooled and the warm air may still be blown from the blowing port 12.

Therefore, as shown in FIG. 2, it is important that the suction port 11 and the blowing port 12 are formed on the same side surface of the housing 10. In this way, a part of cool air blown from the blowing port 12 is suctioned from the suction port 11 again, and thereby the air blown from the blowing port 12 becomes cooler. In particular, for a large flow rate fan having a large blade diameter, this configuration as described above is effective because it is difficult to cool the warm air instantaneously. Further, in terms of downsizing the electric fan, it is also important that the blowing port 12 is formed on the central part of one side surface of the housing 10 and that the suction port 11 is formed on the outer edge part of the blowing port 12, as shown in FIGS. 2 to 4. The electric fan having this configuration can cool air effectively even if the electric fan is a large flow rate fan having a large blade diameter.

The axial flow fan 20 is mounted in the middle of the flow channel between the suction port 11 and the blowing port 12. The axial flow fan 20 is a fan for suctioning air from the suction port 11 into the housing 10 and for blowing the suctioned air from the blowing port 12. As described above, the structure of the electric fan according to the present invention is suitable for a large flow rate fan having a large blade diameter. More specifically, the blade diameter of the axial flow fan is preferably 20 to 50 inches, and is more preferably 24 to 36 inches. In addition, the flow rate of air is preferably 3500 to 35000 m3/h in operation, and is more preferably 5000 to 25000 m3/h. The motor for rotating the axial flow fan 20 may be an internal motor in the axial flow fan 20, or any other non-internal motor may be mounted to rotate the axial flow fan 20 via a belt and a pulley. In the latter case, the rotational frequency of the axial flow fan 20 can be adjusted by using a gear.

In the electric fan of the present invention, an evaporation filter 30 is mounted for passing the air suctioned from the suction port 11, as shown in FIG. 1. The evaporation filter 30 is mounted in a flow channel between the suction port 11 and the blowing port 12. The evaporation filter 30 is typically disposed upstream from the axial flow fan 20. The evaporation filter 30 may be made from a paper such as a corrugated cardboard, or from a plastic such as an open-cell polyurethane foam or a sintered polyethylene material. Since water is introduced to the evaporation filter 30, the evaporation filter 30 is preferably subjected to a treatment for improving the hydrophilicity, in particular when the evaporation filter 30 is made from a plastic.

In the electric fan of the present invention, by using a water supplying system 40 having a tank 41 and the water supplying pipe 42, water is supplied (sprinkled) from a water sprinkler 42a formed on a water supplying pipe 42 disposed over the evaporation filter 30 to the evaporation filter 30, as shown in FIG. 1. That is, the water in the tank 41 is suctioned to the water supplying pipe 42 with a pump (not shown) mounted in the tank 41, and is supplied from the water sprinkler 42a, which is formed over the evaporation filter 30, to the evaporation filter 30. In this way, water can be introduced to the evaporation filter 30 by supplying water from above of the evaporation filter 30. When the air suctioned from the suction port 11 passes through the evaporation filter 30 containing water, the water contained in the evaporation filter 30 is evaporated, and the air is deprived of the vaporization heat required for the vaporization of water, whereby the air is cooled. Additionally, Ag ion ceramic balls can be put in a box 48 mounted in the tank 41 containing water, to suppress the generation of bacteria and to perform air cleaning function. By using a bactericidal lamp instead of the Ag ion ceramic balls, the generation of bacteria can be suppressed and air cleaning function can be performed as well. The position of the bactericidal lamp mounted may be in the tank 41 or may be in the middle of the water supplying pipe 42.

In the electric fan of the present invention, a pre-evaporation filter 35 for passing the air suctioned from the suction port 11 is preferably mounted upstream from the evaporation filter 30, as shown in FIG. 1. As for the mounted position of the pre-evaporation filter 35, the pre-evaporation filter 35 is mounted in the middle of the flow channel between the suction port 11 and the evaporation filter 30. The pre-evaporation filter 35 may be made from a paper such as a corrugated cardboard, or from a plastic such as an open-cell polyurethane foam or an sintered polyethylene material. Since water is introduced to the pre-evaporation filter 35, the pre-evaporation filter 35 is preferably subjected to a treatment for improving the hydrophilicity, in particular when the pre-evaporation filter 35 is made from a plastic.

Preferably, by using the water supplying system 40, water is supplied (sprinkled) from a water sprinkler 42b formed on a water supplying pipe 42 disposed over the pre-evaporation filter 35 to the pre-evaporation filter 35, as shown in FIG. 1. That is, the water in the tank 41 is suctioned to the water supplying pipe 42 with a pump (not shown) mounted in the tank 41, and is supplied from the water sprinkler 42b, which is formed over the pre-evaporation filter 35, to the pre-evaporation filter 35. In this way, water can be supplied from above of the pre-evaporation filter 35, and water can be introduced to the pre-evaporation filter 35. When the air suctioned from the suction port 11 passes through the pre-evaporation filter 35 containing water, the water contained in the pre-evaporation filter 35 is evaporated, and the air is deprived of the vaporization heat required for the vaporization of water, whereby the air is cooled.

By mounting the pre-evaporation filter 35 upstream from the evaporation filter 30 in this way, the air reaching the evaporation filter 30 can be previously cooled. In addition, the evaporation filter 30 is not exposed in the suction port 11, and therefore the evaporation filter 30 is not heated, for example, by sunlight coming through the suction port 11. As a result, the cooling efficiency of the air by the evaporation filter 30 can be improved.

The water supplied by using the water supplying system 40 may be water at ordinary temperature, or water cooled with a chiller. For example, water can be cooled by adding an immersion chiller 45 in a cooling unit 46 connected to the water supplying pipe 42, as shown in FIG. 1. In this case, by making a tube between the tank 41 and the cooling unit 46 thicker than the other part, the water tends to remain in the cooling unit 46, and thereby the cooling efficiency can be improved. Alternatively, by using a plurality of chillers 45, immersion chillers can respectively be added in a plurality of areas formed by partitioning the tank 41.

As the chiller 45, a relatively small chiller having an electric power for cooling of 1 to 10 kW can be used. Although heat is generated in the chiller 45, the heat can be dissipated, for example, by mounting a heat dissipating fan 16a on the rear surface of the housing 10 of the electric fan.

The water which is supplied to the evaporation filter 30 or the pre-evaporation filter 35 but is not evaporated is preferably returned to the tank 41. In order to allow water exchange in the tank 41, a drain cock for draining off water in the tank 41 is preferably mounted on the lower part of the housing 10, for example.

Water may be supplied to the evaporation filter 30 and the pre-evaporation filter 35 by the water supplying system 40 continuously or intermittently. Before stopping the electric fan, the evaporation filter 30 and the pre-evaporation filter 35 may be dried without supplying water. The growth of mold can be prevented by drying the evaporation filter 30 and the pre-evaporation filter 35. The electric fan preferably has a function of adjusting the speed of supplying water in order to adjust the temperature of air. In addition, for drying the evaporation filter 30 and the pre-evaporation filter 35, a drying fan 15 can be mounted in the flow channel between the evaporation filter 30 and the pre-evaporation filter 35, for example. In this case, by rotating the drying fan 15 for about 1 hour by using a timer after the switch of the electric fan is turned off, the growth of mold in the evaporation filter 30 and the pre-evaporation filter 35 can be prevented.

In the electric fan of the present invention, a dustproof filter or an air cleaning filter may be mounted upstream from the evaporation filter 30 or the pre-evaporation filter 35, for example. In this way, the life of the evaporation filter 30 or the pre-evaporation filter 35 can be increased, and clean air is discharged from the blowing port 12. Additionally, the evaporation filter 30 or the pre-evaporation filter 35 may have a function of dustproofing and air cleaning. Further, a pre-filter made from a polyester or a modacrylic fiber may be mounted in the suction port 11.

In the electric fan of the present invention, a cooling coil 50 that is an indirect heat exchanger for cooling the air passed through the evaporation filter 30 is mounted downstream from the evaporation filter 30, as shown in FIG. 1. Additionally, a cooler (chiller 51) is mounted for cooling a coolant flowing inside the cooling coil.

The cooling efficiency of air by the evaporation filter 30 is affected by the temperature of the air suctioned (ambient temperature) and the temperature of the water introduced to the evaporation filter 30. When the ambient temperature is increased, not only the temperature of the air suctioned from the suction port 11 but also the temperature of the water in the tank 41 are increased, whereby it becomes difficult to cool air to a desired temperature. This is particularly notable for the large flow rate fan having a large blade diameter, and a person does not feel cool from the air blown from the blowing port 12 so much when the ambient temperature is increased. On the other hand, as the present invention, by mounting a cooling coil 50 downstream from an evaporation filter 30 and by flowing a coolant cooled forcibly with a chiller 51 inside the cooling coil 50, a person easily feels cool from the air blown from a blowing port 12 even if the ambient temperature is increased. Further, as described above, by forming at least an inner surface of a housing 10 with a heat insulating material and by mounting the evaporation filter 30 (and a pre-evaporation filter 35) and a tank 41 inside the housing 10, the temperature increase of the water in the evaporation filter 30 (and the pre-evaporation filter 35) or the tank 41 can be suppressed. In a traditional electric fan having an evaporation filter, the evaporation filter is exposed to the outside. In particular when the electric fan is used for outdoor space or at a building entrance, sunlight directly illuminates the exposed part of the evaporation filter, and then the temperature of the water in the evaporation filter and the tank is greatly increased. However, in the configuration of the present invention as described above, the electric fan is not sensitive to the ambient temperature and the direct sunlight.

Specific examples of the indirect heat exchanger include multi-tubular heat exchangers, coiled heat exchangers, plate heat exchangers, and spiral heat exchangers, and a heat exchanger used can be suitably selected depending on the cooling performance. As the chiller 45, for example, a relatively small chiller having an electric power for cooling of 1 to 10 kW can be used. Although the water cooled at about 2° C. is discharged from the chiller 51, the water is heated to 10° C. or higher by the cooling coil 50, and therefore the problem of water condensate does not tend to occur. Although heat is generated in the chiller 51, the heat can be dissipated, for example, by mounting a heat dissipating fan 16a on the rear surface of the housing 10 of the electric fan.

In the electric fan of the present invention, a mist sprayer 60 is preferably mounted on the peripheral of the blowing port 12 downstream from the axial flow fan 20, as shown in FIG. 1. In this way, mist can be introduced into air, and eventually, the feeling temperature of the cool wind which is blown from the blowing port 12 can be decreased.

The electric fan of the present invention having the configuration as described above can blow cool wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter.

Although the main object of the electric fan of the present invention is to perform cooling function as well as blowing function of air, the electric fan may be configured to perform heating function by switching instead of cooling function. In this case, the indirect heat exchanger mounted can be utilized effectively. That is, by mounting a heater 52 for heating a heat medium flowing inside the indirect heat exchanger, the air passing through the indirect heat exchanger can be heated. Additionally, an external heater (an electric heater 80 in FIG. 1) can be mounted in the flow channel of air for heating the air directly.

In order to achieve more effective heating function, the electric fan preferably has a hot wind generator 70, and a hot wind discharger 71 which is mounted so that the hot wind from the hot wind generator 70 is discharged along the rotation direction of the air from the axial flow fan 20. The hot wind discharger 71 is preferably mounted downstream from the axial flow fan. In this way, hot wind at about 350° C., for example, which is generated from the hot wind generator 70 is discharged in a condition that hot wind is easily mixed to the flow of air, and thereby the heating efficiency of air is increased. As the hot wind generator 70, a hot wind generator having an electric power for heating of 5 to 15 kW can be used, for example. Although heat is generated around the hot wind generator 70, the heat can be dissipated, for example, by mounting a heat dissipating fan 16b on the rear surface of the housing 10 of the electric fan.

One specific configuration of the hot wind discharger 71 is that a hot wind discharging hole 71b is formed on a ring-shaped tube 71a and that a baffle 71c is mounted on the periphery of the hot wind discharging hole 71b so that the hot wind is discharged along the rotation direction of the ring, as shown in FIG. 5 as the enlarged view. The ring-shaped tube 51a that is the hot wind discharger 71 is disposed coaxially with the axial flow fan 20. In this way, when the hot wind generated from the hot wind generator 70 is discharged from the hot wind discharging hole 71b on the ring-shaped tube 71a, the hot wind is directed to the rotation direction of the air from the axial flow fan 20 by the effect of the baffle 71c. Therefore, the hot wind is discharged in a condition that the hot wind is easily mixed to the flow of air, and thereby the heating efficiency of air is increased.

When the electric fan is operated as a heater, water is not typically supplied to the evaporation filter 30 or the pre-evaporation filter 35. However, water may be supplied to the evaporation filter 30 or the pre-evaporation filter 35. If water is supplied to the evaporation filter 30 or the pre-evaporation filter 35, the heating efficiency is decreased but the air can be humidified. Additionally, Ag ion ceramic balls can be put in a box 48 mounted in the tank 41 containing water, to suppress the generation of bacteria and to perform air cleaning function. By using a bactericidal lamp instead of the Ag ion ceramic balls, the generation of bacteria can be suppressed and air cleaning function can be performed as well. The position of the bactericidal lamp mounted may be in the tank 41 or may be in the middle of the water supplying pipe 42.

The electric fan having the configuration as described above can blow warm wind efficiently even if the electric fan is a large flow rate fan having a large blade diameter.

For example, a caster with rock mechanism may be mounted on the lower part of the housing 10 of the electric fan of the present invention, to obtain a movable electric fan. Additionally, the electric fan may have a configuration in which accessories such as switches for operating the electric fan of the present invention can be retracted inside, to obtain an all-weather electric fan.

DESCRIPTION OF THE REFERENCE NUMERALS

10 housing

11 suction port

12 blowing port

15 drying fan

16a heat dissipating fan

16b heat dissipating fan

20 axial flow fan

30 evaporation filter

35 pre-evaporation filter

40 water supplying system

41 water tank

42 water supplying pipe

42a water sprinkler

42b water sprinkler

45 chiller

46 cooling unit

48 box

50 cooling coil

51 chiller

52 heater

60 mist sprayer

70 hot wind generator

71 hot wind discharger

71a ring-shaped tube

71b hot wind discharging hole

71c baffle

80 electric heater

Claims

1. An electric fan, comprising:

a housing having a suction port for air and a blowing port for air;
an axial flow fan for suctioning air from the suction port into the housing and for blowing the suctioned air from the blowing port;
an evaporation filter for passing the air suctioned from the suction port;
a water supplying system capable of supplying water to the evaporation filter;
an indirect heat exchanger for cooling the air passed through the evaporation filter, the indirect heat exchanger being disposed downstream from the evaporation filter; and
a cooler for cooling a coolant for the indirect heat exchanger;
wherein the suction port and the blowing port are formed on the same side surface of the housing; and
wherein the blowing port is formed on the central part of the side surface of the housing, and the suction port is formed on the outer edge part of the blowing port.

2. The electric fan according to claim 1, further comprising:

a pre-evaporation filter for passing the air suctioned from the suction port, the pre-evaporation filter being disposed upstream from the evaporation filter;
wherein the water supplying system can supply water to the pre-evaporation filter.

3. The electric fan according to claim 1, further comprising:

a mist sprayer disposed on the peripheral of the blowing port.

4. The electric fan according to claim 1,

wherein the axial flow fan has a blade diameter of 20 to 50 inches.

5. The electric fan according to claim 1,

wherein the flow rate of air in operation is 3500 to 35000 m3/h.

6. The electric fan according to claim 2, further comprising:

a mist sprayer disposed on the peripheral of the blowing port.

7. The electric fan according to claim 2,

wherein the axial flow fan has a blade diameter of 20 to 50 inches.

8. The electric fan according to claim 2,

wherein the flow rate of air in operation is 3500 to 35000 m3/h.

9. The electric fan according to claim 3,

wherein the axial flow fan has a blade diameter of 20 to 50 inches.

10. The electric fan according to claim 3,

wherein the flow rate of air in operation is 3500 to 35000 m3/h.

11. The electric fan according to claim 6,

wherein the axial flow fan has a blade diameter of 20 to 50 inches.

12. The electric fan according to claim 6,

wherein the flow rate of air in operation is 3500 to 35000 m3/h.
Patent History
Publication number: 20180149160
Type: Application
Filed: Nov 29, 2016
Publication Date: May 31, 2018
Applicant: EARTH BLOW JAPAN INC. (Saitama)
Inventor: Tetsuya AIZAKI (Saitama)
Application Number: 15/578,167
Classifications
International Classification: F04D 25/08 (20060101); F24F 1/00 (20110101); F24F 6/04 (20060101); F04D 29/58 (20060101); F04D 29/70 (20060101); F24F 6/14 (20060101);