Abstract:
Provided is an air adjuster that maintains low-noise performance of back-inlet types and allows realization of efficient airflow from the front side toward the back side thereof and prevents the occurrence of stagnant air. The air adjuster includes a housing in which air inlets and an air outlet are formed; a blower that sucks in air through the air inlets; and a conditioning unit that conditions the air sucked in by the blower. The air inlets are located on the back side of the housing, and the air conditioned by the conditioning unit is blown to the outside through the air outlet. The housing allows the air to pass through a space between a bottom surface thereof and a placement surface, and the housing is provided with leg units that form a gap whose vertical dimension on the front side is smaller than that on the back side.

Description:
[0001]    This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/JP2011/062349 which has an International filing date of May 30, 2011 and designated the United States of America. 
     
    
     FIELD 
       [0002]    The present invention relates to an air adjuster, such as an air purifier or a humidifier, for adjusting the purity, humidity, and the like of air. 
       BACKGROUND 
       [0003]    Air in a room is contaminated with various substances such as dust, tobacco smoke, and carbon dioxide exhaled by respiration. Because modern houses are highly airtight, such contaminants tend to accumulate in a room, so that it is necessary to actively ventilate air in a room. However, for houses and offices in comparatively heavily air-polluted areas, it is not preferable to ventilate air through a window, because polluted air is undesirably taken into a room. For houses and the like in less air-polluted areas, pollen may be taken into a room depending on the season, which is not desirable for people suffering from hay fever. 
         [0004]    Accordingly, air purifiers of types placed on a floor or a table are used to purify air without opening a window. A typical method of purifying air in a room is to suck in air, collect dust and the like using a filter, and absorb contaminants using activated carbon or the like. Therefore, air purifiers have the following basic structure. 
         [0005]    An air passage in which a blower is disposed is formed in a body of an air purifier. An air inlet is disposed at the entrance of the air passage, and an air outlet is disposed at the exit of the air passage. A dust filter and a deodorizing filter are disposed in the air passage to remove dust, unpleasant odors, and the like. Moreover, an ion generating unit is disposed in the air passage, and ions generated by the ion generating unit are released into a room together with purified air. Airborne mold, bacteria, and the like in the room are inactivated as a result of being surrounded by the released ions. Thus, the air purifier purifies air in a room (see, for example, Japanese Unexamined Patent Application Publication No. 2000-121111). 
         [0006]    Because apparatuses have been designed to provide a better low-noise performance, there are air purifiers having air inlets structured in various ways. The apparatus described in Japanese Unexamined Patent Application Publication No. 2000-121111 is a front-inlet-type apparatus having an air inlet in a front surface thereof. 
         [0007]    However, in general use, air purifiers are placed on a floor surface near a wall while a user is present in a middle part of the room. Therefore, back-inlet-type apparatuses, which have an air inlet in a back surface thereof to reduce air intake noise of the blower heard by a user, are also marketed (see, for example, Japanese Unexamined Patent Application Publication No. 2009-085511). 
       SUMMARY 
       [0008]    With the existing technologies described above, the front-inlet-type apparatus efficiently sucks in contaminated air in a room, including air on the lower front side of the apparatus. However, the noise level for a user during operation is high because the blower air intake noise directly enters the user&#39;s ears. In contrast, the back-inlet-type apparatus has a good low-noise performance. However, air on the lower front side of the apparatus is not easily sucked in, so that contaminated air in a room remains stagnant in a region surrounding the apparatus. 
         [0009]    An object of the present invention, which has been achieved under the circumstances described above, is to provide an air adjuster that can restrict an increase in the noise level thereof, realize efficient airflow from the lower front side toward the back side thereof, and prevent the occurrence of stagnant air. 
         [0010]    An air adjuster according to the present invention includes a housing in which an air inlet and an air outlet are formed; a blower that is disposed in the housing and that sucks in air through the air inlet; and a conditioning unit that is disposed in the housing and that conditions the air sucked in by the blower. The air that has been conditioned by the conditioning unit is blown to the outside through the air outlet. The air inlet is formed in a back surface or in a side surface of the housing. The housing allows the air to pass through a space between a bottom surface thereof and a placement surface, and the housing is provided with a leg unit that forms a gap whose vertical dimension on a front side is smaller than a vertical dimension on a back side. 
         [0011]    According to the present invention, the housing, which has the air inlet formed in the back surface or the side surface thereof, is supported by the leg unit, and the gap, through which air can pass and whose vertical dimension on the front side is smaller than the vertical dimension on the back side, is formed between the bottom surface of the housing and the placement surface. When the blower is activated and air is sucked in through the air inlet in the back surface or the side surface of the housing and airflow toward the air inlet is generated, air on the lower front side of the housing flows through the gap between the bottom surface and the placement surface toward the back surface or the side surface, and the air is sucked in through the air inlet in the back surface or the side surface together with air that has flowed around the housing. The sucked-in air is conditioned by the conditioning unit and is blown to the outside through the air outlet. Thereafter, such sucking and blowing of air are performed repeatedly. 
         [0012]    In the air adjuster according to the present invention, at least one of a lower end portion of a front surface and a front end portion of the bottom surface of the housing may be formed as an inclined surface or a curved surface that is connected to the other of the lower end portion of the front surface and the front end portion of the bottom surface. 
         [0013]    With the present invention, air on the front side of the housing flows along the inclined surface or the curved surface, which is formed at the connection portion between the lower end portion of the front surface of the housing and the front end portion of the bottom surface of the housing, and the air smoothly flows into the gap between the bottom surface of the housing and the placement surface. 
         [0014]    In the air adjuster according to the present invention, the leg unit may be a plurality of legs that are disposed at least at three positions on the bottom surface of the housing. 
         [0015]    With the present invention, the plurality of legs, which are formed at least at three positions on the bottom surface of the housing, form the gap between the bottom surface of the housing and the placement surface, and air on the lower front side of the housing flows through the space between the leg units toward the back side. 
         [0016]    In the air adjuster according to the present invention, the leg unit may be a wall member that extends in a ring-like shape along a peripheral edge of the bottom surface of the housing so as to face downward, the wall member having an opening formed in each of a front surface and a back surface thereof or in each of the front surface and a side surface thereof. 
         [0017]    With the present invention, the wall member, which extends in a ring-like shape along the peripheral edge of the bottom surface of the housing so as to face downward, forms the gap between the bottom surface of the housing and the placement surface, and air on the lower front side of the housing flows toward the back side through both openings formed in the front surface and the back surface of the housing or through both openings formed in the front surface and the side surface of the housing. 
         [0018]    With the present invention, air on the lower front side of the housing flows toward the back side through the gap between the bottom surface and the placement surface, and the air is sucked in through the air inlet formed in the back surface or the side surface. As a result, an air adjuster is provided that can restrict an increase in the noise level thereof as compared with a front-inlet type, realize efficient airflow from the lower front side toward the back side thereof, and prevent the occurrence of stagnant air. 
         [0019]    Moreover, with the present invention, the vertical dimension of the gap between the bottom surface of the housing and the placement surface on the front side is smaller than the vertical dimension on the back side. As a result, an air adjuster is provided with which dust and the like on the floor surface are sucked up with a higher power because the gap on the front side, which is narrow, serves as a nozzle and increases the airflow speed and with which the aesthetic in appearance can be improved because the leg unit disposed on the bottom surface of the housing is difficult to see from the front side. 
         [0020]    The above and further objects and features will more fully be apparent from the following detailed description with accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a front perspective view of an air purifier according to a first embodiment of the present invention. 
           [0022]      FIG. 2  is a back perspective view of the air purifier illustrated in  FIG. 1 . 
           [0023]      FIG. 3  is a longitudinal sectional view illustrating the internal structure of the air purifier illustrated in  FIG. 1 . 
           [0024]      FIG. 4  is an enlarged sectional view illustrating the vicinity of a leg unit of the air purifier illustrated in  FIG. 1 . 
           [0025]      FIG. 5A  illustrates airflow during the operation of an air purifier according to the present invention. 
           [0026]      FIG. 5B  illustrates airflow during the operation of the air purifier according to the present invention. 
           [0027]      FIG. 6A  illustrates airflow during the operation of an air purifier according to a comparative example. 
           [0028]      FIG. 6B  illustrates airflow during the operation of the air purifier according to the comparative example. 
           [0029]      FIG. 7  is a front perspective view of an air purifier according to a second embodiment of the present invention. 
           [0030]      FIG. 8  is a back perspective view of the air purifier illustrated in  FIG. 7 . 
           [0031]      FIG. 9  is a longitudinal sectional view illustrating the internal structure of the air purifier illustrated in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    Hereinafter, embodiments of an air adjuster according to the present invention will be described with reference to the drawings by using an air purifier as an example. 
       First Embodiment 
       [0033]      FIG. 1  is a front perspective view of an air purifier according to a first embodiment of the present invention,  FIG. 2  is a back perspective view of the air purifier illustrated in  FIG. 1 ,  FIG. 3  is a longitudinal sectional view illustrating the internal structure of the air purifier illustrated in  FIG. 1 , and  FIG. 4  is an enlarged sectional view illustrating the vicinity of a leg unit of the air purifier illustrated in  FIG. 1 . In  FIG. 3 , the left side is the front side, and the right side is the back side. 
         [0034]    An air purifier  10  includes a housing  1 . A blower  31 , a duct  26 , a filter  18 , ion generating devices  40  and  46 , and the like are disposed in the housing  1 . 
         [0035]    The housing  1  has an upright substantially rectangular parallelepiped shape and includes a back wall  1   a , a top wall  1   b , a bottom wall  1   c , a front wall  1   d , and side walls  1   e . The bottom wall  1   c  has a substantially rectangular shape in plan view. When the air purifier  10  is placed on a floor, the bottom wall  1   c  serves as a bottom portion of the housing  1  that faces a floor surface (placement surface). The top wall  1   b  has the same shape as the bottom wall  1   c  in plan view. A back part of the top wall  1   b  is inclined downward. The back wall  1   a  and the front wall  1   d  are disposed so as to extend substantially parallel to each other and face each other. The back wall  1   a  serves as a back portion of the housing  1 , and the front wall  1   d  serves as a front portion of the housing  1 . The side walls  1   e  serve as side portions of the housing  1 . Generally, the air purifier  10  is placed near a wall in a room such that the back wall  1   a  faces the wall in the room. 
         [0036]    A lower end portion  1   d   1  of the front wall  1   d  of the housing  1  is bent backward from a position at a distance h 3  from the floor surface and forms an inclined surface that is connected to a front end portion of the bottom wall  1   c , which is inclined downward toward the front side. A plurality of air inlets  16 , through which air in a room is sucked in, is formed in the back wall  1   a  of the housing  1 . Each of the air inlets  16  has a rectangular shape whose longitudinal direction is the vertical direction. The air inlets  16  are arranged two-dimensionally in the vertical and horizontal directions with intervals therebetween. 
         [0037]    An air outlet  14 , through which purified air is blown into a room, is formed in the top wall  1   b  of the housing  1 . In the present embodiment, the air outlet  14  has a substantially oval opening whose transversal direction is the direction in which the back wall  1   a  and the front wall  1   d  face each other. The shape of the opening of the air outlet  14  is not limited to the oval shape and may be, for example, a rectangular shape or a shape in which a plurality of slits are arranged. The air outlet  14  need not be formed in the top wall  1   b  and may be formed, for example, in the front wall  1   d.    
         [0038]    The filter  18  is a HEPA (High Efficiency Particulate Air) filter and is disposed in the housing  1  so as to face the air inlets  16 . Air that has been sucked into the housing  1  through the air inlets  16  becomes purified air as the air passes through the filter  18  and foreign substances are removed. 
         [0039]    The blower  31  sucks room air into the housing  1  and blows the air, which has been purified by the filter  18 , into the room through the air outlet  14 . Hereinafter, the structure of the blower  31  will be described in detail. 
         [0040]    The blower  31  is a centrifugal fan (sirocco fan) that includes an impeller  36  and a casing  32  in which the impeller  36  is rotatably mounted. The impeller  36  has a cylindrical shape and has a rotation axis extending in the front-back direction. The impeller  36  is disposed in front of the filter  18 . The impeller  36  is a multi-blade impeller that includes a plurality of blades  36   f  whose portions near the rotation center are displaced in the rotation direction relative to the outer edges. The impeller  36  includes a bearing plate at one end thereof in the rotation axis direction. An output shaft of a motor  28  for driving a fan is attached to a shaft hole formed at the center of the bearing plate. When the motor  28  is driven, the impeller  36  sucks air into a hollow space in a central portion thereof through an opening at the other end in the rotation axis direction and releases air from spaces between the blades  36   f  in the outer peripheral portion. 
         [0041]    The casing  32  includes a guide wall  32   a  that has an arc shape and an air outlet portion  32   b  that has a rectangular pipe shape having an opening facing upward. The air outlet portion  32   b  protrudes from a part of the guide wall  32   a  in one of the tangential directions of the guide wall  32   a . The guide wall  32   a  guides airflow that is generated by rotation of the impeller  36  toward the rotation direction of the impeller  36  and increases the speed of the airflow. 
         [0042]    The casing  32  is a combination of a casing body  33  that has a bowl shape and a cover plate  34  that blocks an opening side of the casing body  33 . The casing body  33  forms the guide wall  32   a  and an opening portion for the air outlet portion  32   b . The cover plate  34  is attached to the casing body  33  using a plurality of male screws. 
         [0043]    The duct  26  is disposed above the blower  31  and has a rectangular pipe shape having an opening at the upper end. The upper end of the duct  26  is connected to the air outlet  14 , and the lower end of the duct  26  is connected to the air outlet portion  32   b  of the blower  31 . The duct  26  includes a front wall  26   a  that faces the front wall  1   d  of the housing  1  and that is inclined toward the back side. The duct  26  is integrally formed with the casing body  33  and the cover plate  34 . The duct  26  functions as an air guide passage for guiding purified air blown out of the air outlet portion  32   b  toward the air outlet  14 . 
         [0044]    In the present embodiment, a first ion generating device  40  is attached to the guide wall  32   a  of the casing  32 , and a second ion generating device  46  is attached to the front wall  26   a  of the duct  26 . The ion generating devices  40  and  46  include ion generating units  41 , and generate positive ions and negative ions. 
         [0045]    A leg unit is disposed on the bottom wall  1   c  of the casing  1 , and a gap, through which air flows, is formed between the bottom wall  1   c  and the floor surface. To be specific, four legs are attached to the four corners of the bottom wall  1   c , and the length of legs  50  on the front side is shorter than the length of the legs  51  on the back side. Thus, a gap h 1  between the front end of the bottom wall  1   c  and the floor surface is narrower than a gap h 2  between the back end of the bottom wall  1   c  and the floor surface. 
         [0046]    Next, the operation of the air purifier  10  will be described.  FIGS. 5A and 5B  illustrate airflow generated during the operation of an air purifier according to the present invention, and  FIGS. 6A and 6B  illustrate airflow generated during the operation of an air purifier according to a comparative example. Note that, when the air purifier according to the comparative example is placed on a floor surface, a gap through which air flows is not formed between the bottom surface of the casing and the floor surface.  FIGS. 5A and 6A  are plan views, and  FIGS. 5B and 6B  are side views. 
         [0047]    When the blower  31  is driven, the impeller  36  rotates and generates airflow with which air in a room is sucked into the housing  1  through the air inlets  16 . The filter  18  removes foreign substances, such as dust, from the air sucked into the housing  1 . Purified air, which has passed through the filter  18 , is sucked into the casing  32 , and forms a laminar flow due to the presence of the guide wall  32   a  surrounding the impeller  36 . The laminar flow of the air is guided toward the air outlet portion  32   b  along the guide wall  32   a , and the air is blown into the duct  26  from the air outlet portion  32   b.    
         [0048]    The ion generating device  40 , which is disposed on the guide wall  32   a , generates positive ions and negative ions in the purified air that flows along the guide wall  32   a . Moreover, the ion generating device  46 , which is disposed on the front wall  26   a  of the duct  26 , generates positive ions and negative ions in the purified air that flows through the duct  26 , thereby increasing the amount of positive ions and negative ions in the purified air. The positive and negative ions, which have been generated by the ion generating devices  40  and  46 , are released to the outer space together with the purified air through the air outlet  14 . At this time, airflow from the air outlet  14  to the outside is generated. 
         [0049]    Usually, air in a region of up to a height of about 30 cm from a floor surface, which is called a stagnant region, hardly moves. When a floor-standing air purifier is placed on a floor surface, air circulates since airflow is forcibly formed as a result of blowing. However, air in the vicinity of the floor surface of up to several centimeters from the floor surface does not move easily due to friction between the air and the floor surface. Under such conditions, air in the vicinity of the air inlets  16  is sucked in at first, and the pressure of the air turns relatively negative to the surrounding air, so that the negative pressure drives the surrounding air toward the air inlets  16 . 
         [0050]    However, immediately after the operation has been started, dust and pollen in the vicinity of the floor surface do not move. After the operation has been started and when circulating airflow has been formed in a room as the air purifier  10  sucks and blows air, dust and pollen near the floor surface start moving toward the air purifier  10  and reach the air inlets  16  together with surrounding airflow. With a back-inlet-type air purifier, the air pressure in a space between the apparatus and a wall behind the apparatus becomes negative, and the surrounding air flows into this space. In this case, with the air purifier  10  according to the present invention, in addition to air flowing around the side surfaces, stagnant air on the lower front side moves toward the back side due to airflow passing through the gap between the bottom wall  1   c  and the floor surface, and thereby the stagnant air is easily removed. On the other hand, with an air purifier  100  according to the comparative example, stagnant air on the lower front side is not easily removed, because airflow exists only around the side surfaces. 
         [0051]    As illustrated in  FIG. 4 , with the air purifier  10  according to the present invention, the shorter the distance L from the position at which the back wall  1   a  and the bottom wall  1   c  of the housing  1  intersect each other to the lower end of the air inlets  16  on the back side, the larger the influence of negative pressure on the back side of the housing  1  on the airflow passing through the gap between the bottom wall  1   c  and the floor surface, and the more easily air is sucked in from the floor surface. The larger the gaps h 1  and h 2  between the bottom wall  1   c  and the floor surface, the more easily air flows through the gap between the bottom wall  1   c  and the floor surface. 
         [0052]    On the other hand, if the gap h 1  between the bottom wall  1   c  on the front side and the floor surface is too large, the legs  50  on the front side become too long and the stability and the aesthetic in appearance of the air purifier  10  are impaired. Therefore, with the air purifier  10  according to the present invention, by increasing the gap h 2  on the back side while reducing the gap h 1  on the front side, it becomes possible to increase air-sucking efficiency while preventing the air purifier  10  from looking unstable and maintaining its aesthetic in appearance. Moreover, the lower end portion  1   d   1  of the front wall  1   d , which extends to the gap h 1  between the front wall  1   d  and the floor surface, is formed as an inclined surface connected to the bottom wall  1   c . Therefore, resistance to flow of air that is sucked into the gap between the bottom surface and the floor surface from the lower front side of the air purifier  10  is reduced, so that the air flows smoothly and stagnant air is easily removed. Furthermore, the gap h 1  on the front side, which is narrow, serves as a nozzle and increases the airflow speed, so that dust and the like on the floor surface are sucked up with a higher power with a lower effect of dust adhesion. It is preferable that the height h 3 , from the floor surface, of a ridge at which the lower end portion  1   d   1  of the front wall  1   d  is bent toward the bottom wall  1   c  be larger than the maximum height of stagnant air. However, considering that priority may be placed on the aesthetic in appearance, it is preferable that the height h 3  be smaller than about 10 cm. 
         [0053]    In the first embodiment, the four legs  50  and  51  are disposed on the four corners of the bottom surface (the bottom wall  1   c ) of the housing  1 . However, this is not necessarily the case. For example, at least three legs may be disposed on the bottom surface by, for example, disposing two legs on the left and right front corners and one leg at the middle of a back portion of the bottom surface. 
       Second Embodiment 
       [0054]      FIG. 7  is a front perspective view of an air purifier according to a second embodiment of the present invention,  FIG. 8  is a back perspective view of the air purifier illustrated in  FIG. 7 , and  FIG. 9  is a longitudinal sectional view illustrating the internal structure of the air purifier illustrated in  FIG. 7 . The second embodiment differs from the first embodiment only in terms of the structure of the leg unit. 
         [0055]    The leg unit of the second embodiment is a wall member  52  integrally formed with the bottom wall  1   c  of the housing  1 . The wall member  52  has a rectangular ring-like shape extending along the peripheral edge of the bottom wall  1   c . An end of the wall member  52 , which protrudes downward, is placed on the floor surface. The wall member  52  includes wall portions  52   a  and  52   b , which face each other, on the front and back sides thereof. Openings  52   c , through which air flows, are formed in the wall portions  52   a  and  52   b . As with the first embodiment, the height of the wall portion  52   a  on the front side is smaller than the height of the wall portion  52   b  on the back side, so that the gap h 1  between the bottom wall  1   c  of the housing  1  and the floor surface is narrower than the gap h 2  on the back side. Moreover, the vertical dimension of the opening  52   c  in the wall portion  52   a  on the front side is smaller than the vertical dimension of an opening  52   c  in the wall portion  52   b  on the back side. 
         [0056]    In the embodiments described above, the air inlets  16  are formed in the back surface (the back wall  1   a ) of the housing  1 . However, this is not necessarily the case, and the air inlets  16  may be formed in a side surface (side wall  1   e ) of the housing  1 . In the case of forming the air inlets in a side surface (side wall  1   e ) of the housing  1  in the second embodiment, openings through which air flows are formed in the wall portions on the front side and on the side of the wall member  52 . 
         [0057]    In the embodiments described above, the lower end portion  1   d   1  of the front wall  1   d  of the housing  1  is formed as an inclined surface that is connected to the front end of the bottom wall  1   c . Alternatively, the lower end portion  1   d   1  of the front wall  1   d  may be formed as, instead of an inclined surface, an outwardly convex curved surface that is connected to the front end of the bottom wall  1   c . As a further alternative, instead of the lower end portion of the front wall  1   d , a front end portion of the bottom wall  1   c  may be formed as an inclined surface or a curved surface that is connected to the lower end of the front wall  1   d . Also, both the lower end portion of the front wall  1   d  and the front end portion of the bottom wall  1   c  may be formed as inclined surfaces or curved surfaces that are connected to each other. In any of these cases, as in the embodiments described above, an airflow resistance reduction effect can be obtained. 
         [0058]    In the embodiments described above, an air purifier is used as an example for an air adjuster according to the present invention. However, the present invention can also be applied to various air adjusters such as humidifiers and air conditioners placed on a floor or a table. In particular, the present invention can be selectively applied to any types of air adjusters having an air inlet in a part thereof that does not face a user (the back surface or the side surfaces of the casing) in order to provide a low noise air intake performance. 
         [0059]    As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiments are therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.