Patent Publication Number: US-2023151999-A1

Title: Blow-out unit and air conditioning apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of International Patent Application No. PCT/JP2021/026805, filed on Jul. 16, 2021, and claims priority to Japanese Patent Application No. 2020-125664, filed on Jul. 22, 2020 and priority to Japanese Patent Application No. 2020-125665, filed on Jul. 22, 2020. The contents of these priority applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a blow-out unit placed at a blow-out port of an air flow path through which air is blown out toward a room, the blow-out unit configured to blow out, toward the room, air supplied thereto through the air flow path. 
     BACKGROUND 
     Patent Literature 1 (JP 2007-155309 A) discloses an air flow direction adjustment flap disposed at an air blow-out port of an air conditioner. According to Patent Literature 1, the air flow direction adjustment flap can be subjected to an angular adjustment relative to a rotating shaft, and is connected to an air flow direction adjusting motor to be controlled for adjusting an air blow-out direction. 
     According to Patent Literature 1, the rotating shaft of the air flow direction adjustment flap is located at a center of the air flow direction adjustment flap as seen in a section taken along a direction perpendicular to a direction along which the rotating shaft extends. This configuration is less likely to achieve an accurate air flow direction adjustment since air is disadvantageously blown out through gaps formed near two ends of the air flow direction adjustment flap, as seen in the section, when the air flow direction adjustment flap turns. 
     SUMMARY 
     One or more embodiments of the present disclosure provide a blow-out port with improved degree of freedom as to an air flow direction adjustment, with a simple structure. 
     A blow-out unit according to the present disclosure is a blow-out unit placed at a blow-out port of an air flow path through which air is blown out toward a room, the blow-out unit configured to blow out, toward the room, air supplied thereto through the air flow path. The blow-out unit includes a first member and a second member each placed in the blow-out port. The first member is a plate member. The plate member includes a first side and is configured to turn on a rotating shaft located away from the first side so that the first side moves away from the blow-out port toward the air flow path. The second member is different in placement position from the plate member in the blow-out port, and extends along the first side of the plate member. The plate member and the second member change a first air flow direction of air to be blown out toward the blow-out port through the air flow path, to a second air flow direction. The plate member turns to change the second air flow direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view illustrating a blow-out unit  1  according to first embodiments together with a ceiling, the blow-out unit  1  seen from below. 
         FIG.  2 A  is a vertical sectional view illustrating the blow-out unit  1  according to the first embodiments in a state in which a turning angle of a plate member  10  of the blow-out unit  1  is 45° relative to the horizontal. 
         FIG.  2 B  is a vertical sectional view illustrating the blow-out unit  1  according to the first embodiments in a state in which the turning angle of the plate member  10  of the blow-out unit  1  is 80° relative to the horizontal. 
         FIG.  3 A  is a diagram illustrating a result of a simulation performed as to an air flow direction of air blown out by the blow-out unit  1  according to the first embodiments in the state in which the turning angle of the plate member  10  is 45° relative to the horizontal. 
         FIG.  3 B  is a diagram illustrating a result of the simulation performed as to the air flow direction of air blown out by the blow-out unit  1  according to the first embodiments in the state in which the turning angle of the plate member  10  is 80° relative to the horizontal. 
         FIG.  4    is a vertical sectional view illustrating a state in which the plate member  10  of the blow-out unit  1  according to the first embodiments is on the blow-out port P and a state in which the plate member  10  turns 90° toward an air flow path S.  FIG.  4    also illustrates geometric parameters of the blow-out unit  1 . 
         FIG.  5    is a control block diagram illustrating the blow-out unit  1  according to the first embodiments. 
         FIG.  6    is a vertical sectional view illustrating a plate member  10   p  of a blow-out unit  1  according to Modification 1A. 
         FIG.  7 A  is a vertical sectional view illustrating a blow-out unit  1   c  according to Modification 1C. 
         FIG.  7 B  is a perspective view illustrating the blow-out unit  1   c  according to Modification 1C, the blow-out unit  1   c  seen from below. 
         FIG.  7 C  is a perspective view illustrating the blow-out unit  1   c  according to Modification 1C together with a ceiling, the blow-out unit  1   c  seen from below.  FIG.  7 C  also illustrates blow-out ports P 1  and P 2  which are open. 
         FIG.  8    is a vertical sectional view illustrating a blow-out unit  1   d  according to Modification 1D. 
         FIG.  9    is a perspective view illustrating the blow-out unit  1   d  according to Modification 1D, the blow-out unit  1   d  seen from below. 
         FIG.  10    is a perspective view illustrating the blow-out unit  1   d  according to Modification 1D placed in a ceiling  2 , the blow-out unit  1   d  seen from below.  FIG.  10    also illustrates four blow-out ports which are open. 
         FIG.  11    is a perspective view illustrating a blow-out unit  100  according to second embodiments. 
         FIG.  12    is a vertical sectional view schematically illustrating a flow of air in the blow-out unit  100  according to the second embodiments. 
         FIG.  13 A  is a vertical sectional view illustrating the blow-out unit  100  according to the second embodiments.  FIG.  13 A  also illustrates a first plate member  10  and a second plate member  20  which are in a first state. 
         FIG.  13 B  is a vertical sectional view illustrating the blow-out unit  100  according to the second embodiments.  FIG.  13 B  also illustrates the first plate member  10  and the second plate member  20  which are in a second state. 
         FIG.  14 A  is a diagram illustrating a turning angle of the first plate member  10 , a turning angle of the second plate member  20 , and a blow distance D 1  of air in the blow-out unit  100  according to the second embodiments.  FIG.  14 A  illustrates a case where the blow distance D 1  is long. 
         FIG.  14 B  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the blow distance D 1  of air in the blow-out unit  100  according to the second embodiments.  FIG.  14 B  illustrates a case where the blow distance D 1  is medium. 
         FIG.  14 C  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the blow distance D 1  of air in the blow-out unit  100  according to the second embodiments.  FIG.  14 C  illustrates a case where the blow distance D 1  is short. 
         FIG.  15 A  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and an air flow direction in the blow-out unit  100  according to the second embodiments.  FIG.  15 A  illustrates a case where an air current angle is 20° relative to the horizontal. 
         FIG.  15 B  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the air flow direction in the blow-out unit  100  according to the second embodiments.  FIG.  15 B  illustrates a case where the air current angle is 30° relative to the horizontal. 
         FIG.  15 C  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the air flow direction in the blow-out unit  100  according to the second embodiments.  FIG.  15 C  illustrates a case where the air current angle is 45° relative to the horizontal. 
         FIG.  15 D  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the air flow direction in the blow-out unit  100  according to the second embodiments.  FIG.  15 D  illustrates a case where the air current angle is 65° relative to the horizontal. 
         FIG.  15 E  is a diagram illustrating the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the air flow direction in the blow-out unit  100  according to the second embodiments.  FIG.  15 E  illustrates a case where the air current angle is 90° relative to the horizontal. 
         FIG.  16    is a control block diagram illustrating the blow-out unit  100  according to the second embodiments. 
         FIG.  17    is a perspective view illustrating a blow-out unit  100   a  according to Modification 2B. 
         FIG.  18    is a perspective view illustrating a blow-out unit  100   b  according to Modification 2C. 
     
    
    
     DETAILED DESCRIPTION 
     First Embodiments 
     (1) Configuration of Blow-Out Unit  1   
     A blow-out unit  1  is placed at a blow-out port P of an air flow path S through which air is blown out toward a room  3 , and is configured to blow out, toward the room  3 , air supplied thereto through the air flow path S. As used herein, air to be supplied to the blow-out unit  1  involves, for example, outside air or indoor air to be blown out as it is, and outside air or indoor air that is heated, cooled, dehumidified, or humidified. The blow-out port P is bored in a ceiling or a wall of the room. The blow-out unit  1  is located nearer to the air flow path S than to the blow-out port P and is placed on an attic or behind a sidewall. 
     The blow-out unit  1  is described with reference to the drawings.  FIG.  1    is a perspective view illustrating the blow-out unit  1  together with the ceiling, the blow-out unit  1  seen from below.  FIGS.  2 A and  2 B  are vertical sectional views each illustrating the blow-out unit  1  placed on the attic. Each  FIG.  3 A  and  FIG.  3 B  is a diagram illustrating a result of a simulation to be performed as to a flow of air in the blow-out unit  1  illustrated in each  FIG.  2 A  and  FIG.  2 B  respectively.  FIG.  4    is a diagram illustrating a range of a turning angle of a plate member  10  in the blow-out unit  1 .  FIG.  5    is a control block diagram illustrating the blow-out unit  1 . 
     The blow-out unit  1  includes the plate member  10 , a guide portion  200 , a chamber box  30 , a panel  33 , a control unit  40 , and a motor  41 . The chamber box  30  has a box shape and includes an intake port connected to a duct, and a blow-out port through which air is blown out. A configuration of the chamber box  30  will be described later. The blow-out unit  1  is placed on the attic such that the blow-out port of the chamber box  30  is aligned over an opening in the ceiling  2  of the room. The chamber box  30  defines a part of the air flow path S. The blow-out port of the chamber box  30  serves as the blow-out port P of the air flow path S. The plate member  10  and the guide portion  200  are placed in the blow-out port P. In the first embodiments, the blow-out port P has a rectangular shape as seen from below. The panel  33  is placed on the ceiling from below so as to cover an outer periphery of the blow-out port P in the ceiling. The blow-out unit  1  blows out air supplied thereto through the chamber box  30 , toward the room  3  by a turn of the plate member  10 . 
     The plate member  10  is a rectangular plate having a predetermined thickness. The plate member  10  is placed such that a surface thereof is flush with the ceiling. The plate member  10  includes a first surface  101  fronting onto the room and a second surface  102  fronting onto the air flow path S. The plate member  10  includes a first side  11   a  extending longitudinally and facing the guide portion  200 , and a second side  12   a  extending in parallel with the first side  11   a  and abutting on a first wall surface  31  of the chamber box  30 . The plate member  10  is substantially identical in longitudinal length with the blow-out port P. 
     The shape of the plate member  10  is appropriately changeable in accordance with the shape of the blow-out port P. The plate member  10  may have a square shape in addition to the rectangular shape. The plate member  10  may be chamfered. The plate member  10  has a thickness D that is not necessarily uniform. The plate member  10  may have a thickness that gradually decreases from a center of the plate member  10  toward ends on the four sides of the plate member  10 . 
     In a state in which the plate member  10  is in a position that covers the blow-out port P as illustrated in  FIG.  4   , as seen in a section taken along a direction perpendicular to the blow-out port P and from the plate member  10  to the guide portion  200  (hereinafter, this section is referred to as a section X), the plate member  10  includes a first end  11  located near the guide portion  200 , and a second end  12  located near the first wall surface  31  of the chamber box  30 . The first end  11  is located on the first side  11   a  of the plate member  10 . The second end  12  is located on the second side  12   a  of the plate member  10 . The plate member  10  includes a rotating shaft  15  disposed near the second end  12 . A distance between the rotating shaft  15  and the second end  12  is equal to or less than one-third of a distance (a length L) between the first end  11  and the second end  12  of the plate member  10 . Further, the distance between the rotating shaft  15  and the second end  12  may be equal to or less than a half of the thickness D of the plate member  10 . This configuration enables a reduction in volume of air flowing through a gap formed between the plate member  10  and the first wall surface  31  of the chamber box  30  when the plate member  10  turns. This configuration also inhibits the second end  12  from protruding from the blow-out port P toward the room when the plate member  10  turns. As illustrated in  FIG.  4   , the plate member  10  is turnable 90° on the rotating shaft  15  toward the air flow path S. The plate member  10  may be configured to turn on the rotating shaft  15  from 0° toward the air flow path S within an angular range from 45° or more to less than 90°. The plate member  10  may be configured to turn within any angular range as long as the plate member  10  is capable of adjusting an air flow direction. 
     The guide portion  200  is placed in the blow-out port P so as to face the plate member  10 . The guide portion  200  is juxtaposed to the first end  11  of the plate member  10  as seen in the section X. The guide portion  200  includes, as seen in the section X, a first surface  210  fronting onto the air flow path S, a second surface  220  fronting onto the room, a third surface  23  abutting on a second wall surface  32  of the chamber box  30 , and a fourth surface  24  abutting on the first end  11  of the plate member  10 . Specifically, the first surface  210  extends from a first end to a second end of the guide portion  200 . The first end of the guide portion  200  is juxtaposed to the first end  11  of the plate member  10 . The second end of the guide portion  200  is located farther from the room than the first end of the guide portion  200  is, on the air flow path S. In addition, the second end of the guide portion  200  is located farther from the first end  11  of the plate member  10  than the first end of the guide portion  200  is. In other words, the first surface  210  is inclined downward from the second wall surface  32  toward the plate member  10 , that is, from the air flow path S toward the room. In the example of  FIG.  4    (a sectional view), the first surface  210  is inclined linearly (i.e., in a plane form). The first surface  210  may alternatively be inclined while being curved (i.e., in a curved form). The second surface  220  is flush with the ceiling  2 . In the state in which the plate member  10  is in the position that covers the blow-out port P, the first surface  101 , which fronts onto the room, of the plate member  10  is flush with the second surface  220 . The second surface  220  has a rectangular shape as seen from below. The second surface  220  includes a first side  221  extending longitudinally and also extending in parallel with the first side  11   a  of the plate member  10 , and a second side  222  extending in parallel with the first side  221  and abutting on the second wall surface  32  of the chamber box  30 . The second surface  220  may be substantially identical in longitudinal length with the blow-out port P. The third surface  23  is in contact with the second wall surface  32  of the chamber box  30  so as to prevent air from flowing through a gap between the third surface  23  and the second wall surface  32 . The fourth surface  24  is located between the first surface  210  and the second surface  220 , and is parallel with the third surface  23 . 
     The shape of the second surface  220  of the guide portion  200  is appropriately changeable in accordance with the shape of the blow-out port P. The second surface  220  may have a square shape in addition to the rectangular shape. The second surface  220  may be chamfered. 
     As illustrated in  FIG.  4   , the second surface  220  of the guide portion  200  and the first surface  101 , which fronts onto the room, of the plate member  10  are flush with each other in the state in which the plate member  10  is in the position that covers the blow-out port P. Alternatively, one of the plate member  10  and the second surface  220  of the guide portion  200  may be located nearer to the air flow path S than the other is. 
     As illustrated in  FIG.  4   , the plate member  10  is turnable 90° until the second surface  102  becomes parallel with the first wall surface  31  from the state in which the plate member  10  is in the position that covers the blow-out port P. An air flow direction and an air volume change in accordance with the turning angle of the plate member  10 . As illustrated in  FIG.  4   , in the state of the plate member  10  indicated with a solid line, that is, in the state in which the plate member  10  is in the position that covers the blow-out port P, the blow-out port P is closed with the plate member  10  and the guide portion  200 . 
     The chamber box  30  has the box shape and includes the intake port connected to the duct, and the blow-out port through which air is blown out. The intake port may be connected via the duct to an air treatment unit of a ventilation apparatus, an air conditioning apparatus, or the like. The blow-out port is substantially identical in shape with the opening in the ceiling. The chamber box  30  includes four wall surfaces extending perpendicularly to the blow-out port P. The four wall surfaces have ends that define the blow-out port P. The four wall surfaces include the first wall surface  31  located near the plate member  10  and the second wall surface  32  located near the guide portion  200  as seen in the section X. The intake port of the chamber box  30  may be formed in an upper portion of the chamber box  30  or may be formed in one of the wall surfaces of the chamber box  30 . In the blow-out port, the plate member  10  and the guide portion  200  are placed. 
     The blow-out unit  1  also includes the panel  33 . The panel  33  is placed on the ceiling  2  from below so as to cover the outer periphery of the blow-out port P in the ceiling  2 . The panel  33  is a frame having a predetermined thickness. The panel  33  protrudes inwardly from the ceiling  2  so as to partially cover the blow-out port P. The panel  33  covers a part of the second end  12  of the plate member  10  from below as seen in the section X. The panel  33  also covers a part of the second surface  220  of the guide portion  200  from below as seen in the section X. The panel  33  has a surface fronting onto the room, and this surface is located nearer to the room than the first surface  101  of the plate member  10  and the second surface  220  of the guide portion  200  are. Alternatively, the surface, which fronts onto the room, of the panel  33  may be flush with the first surface  101  of the plate member  10  and the second surface  220  of the guide portion  200 . The panel  33  may cover only the ceiling  2 . However, the panel  33 , which protrudes inwardly from the ceiling  2  so as to partially cover the blow-out port P, inhibits air from flowing through a gap between the second end  12  of the plate member  10  and the first wall surface  31  of the chamber box  30 . 
     The motor  41  allows the plate member  10  to turn on the rotating shaft  15 . The motor  41  may be a stepping motor. The motor  41  may be placed in or outside the chamber box  30 . 
     The control unit  40  is configured to control the motor  41 . The control unit  40  is a computer. The control unit  40  includes a processor and a memory. The control unit  40  may be a microcomputer. The control unit  40  may be placed anywhere. The control unit  40  may be configured to control a plurality of blow-out units  1  at the same time. 
     The control unit  40  may perform control in accordance with an instruction from a remote controller operated by a user. 
     (2) Air Flow Direction Adjustment 
     In the blow-out unit  1 , the plate member  10  and the first surface  210  of the guide portion  200  change a first air flow direction of air flowing toward the blow-out port P through the air flow path S, to a second air flow direction. In the state in which the plate member  10  is in the position that covers the blow-out port P, the blow-out port P is closed with the plate member  10  and the guide portion  200 . When the plate member  10  turns, the first end  11  of the plate member  10  moves away from the blow-out port P toward the air flow path S, so that the blow-out port P is opened. Air is thus blown out toward the room  3  through the blow-out port P. Air flowing through the air flow path S passes through a clearance between the first surface  101  of the plate member  10  and the first surface  210  of the guide portion  200 , and then is blown out toward the room  3  through the blow-out port P. On the air flow path S, the air flows in the first air flow direction F 1  that is parallel with the first wall surface  31  or the second wall surface  32 . When the air passes through the clearance between the first surface  101  of the plate member  10  and the first surface  210  of the guide portion  200 , the first air flow direction F 1  changes to the second air flow direction F 21  or F 22 . The second air flow direction depends on the inclination angle of the first surface  210  of the guide portion  200  and the turning angle of the plate member  10 . The inclination angle of the first surface  210  of the guide portion  200  is designed and fixed for each blow-out unit  1  in advance. The inclination angle of the first surface  210  of the guide portion  200  may fall within, for example, a range from 20° or more to 65° or less relative to the first air flow direction. The inclination angle of the first surface  210  may fall within a range from 25° or more to 70° or less, or from 40° or more to 55° or less relative to the horizontal. The turning angle of the plate member  10  changes in such a manner that the motor  41  causes the plate member  10  to turn. 
     The second air flow direction changes in accordance with the turning angle of the plate member  10 . A simulation was performed on the blow-out unit  1  for examining how the air flow direction of air to be blown out toward the room  3  through the blow-out port P changes by changing the turning angle of the plate member  10 . The simulation was performed under conditions that a system is entirely set in an isothermal field and a volume of air to be blown out is 10 m 3 /min. The simulation was performed on the case of the turning angle of the plate member  10  in the blow-out unit  1  illustrated in  FIG.  2 A  and  FIG.  2 B .  FIGS.  3 A and  3 B  respectively illustrate results of the simulation. 
     In  FIGS.  2 A,  3 A,  2 B, and  3 B , the first surface  210  of the guide portion  200  is inclined 35° relative to the horizontal. As illustrated in  FIGS.  2 A and  3 A , the second air flow direction F 21  is tilted 40° relative to the horizontal when the plate member  10  turns 45° relative to the horizontal. Likewise, as illustrated in  FIGS.  2 B and  3 B , the second air flow direction F 22  is tilted 70° relative to the horizontal when the plate member  10  turns 80° relative to the horizontal. It is apparent from the results of the simulation that in the blow-out unit  1 , an angular change from the first air flow direction F 1  (the vertical direction) to the second air flow direction F 21  or F 22  decreases as the turning angle of the plate member  10  relative to the horizontal increases. 
     (3) Geometric Parameters of Blow-Out Unit  1   
     A description will be given of geometric parameters of the blow-out unit  1 .  FIG.  4    illustrates the geometric parameters of the blow-out unit  1  as seen in the vertical sectional view (the section X). 
     The length L between the first end  11  and the second end  12  of the plate member  10  may satisfy the following condition. The length L and a length W of the blow-out port P in the direction from the first end  11  to the second end  12  (i.e., a width of the air flow path; in  FIG.  4   , a distance between the first wall surface  31  and the second wall surface  32 ) may satisfy the following condition represented by Formula (1). 
         W/ 4 &lt;L&lt;W/ 2  (1)
 
     In other words, the length L of the plate member  10  may be shorter than a length W-L of the guide portion  200  in the blow-out port P. 
     The thickness D of the plate member  10  may satisfy the following condition represented by Formula (2). 
       0 &lt;D&lt;W/ 8  (2)
 
     In other words, the air flow direction is controlled smoothly by setting the thickness D of the plate member  10  within a certain range. 
     A length H 1  of the fourth surface  24  of the guide portion  200  may satisfy the following condition represented by Formula (3). 
       0 ≤H   1   &lt;W/ 8  (3)
 
     In other words, the air flow direction is controlled smoothly by setting the length H 1  of the fourth surface  24  within a certain range. 
     A distance of the first surface  210  of the guide portion  200  along the first air flow direction F 1  (i.e., an inclined surface height H 2 ) satisfies the following condition represented by Formula (4). 
       0≤H 2 &lt;W  (4)
 
     In other words, the air flow direction is controlled smoothly by setting the inclination angle of the first surface of the guide portion  200  within a certain range. 
     (4) Features 
     (4-1) 
     The blow-out unit  1  according to one or more embodiments is placed at the blow-out port P of the air flow path S through which air is blown out toward the room  3 , and is configured to blow out, toward the room  3 , air supplied thereto through the air flow path S. The blow-out unit  1  includes the plate member  10  and the guide portion  200 . The plate member  10  is configured to turn on the rotating shaft  15  so that the state in which the plate member  10  is in the position that covers the blow-out port P shifts to the state in which the plate member  10  is on the air flow path S. The guide portion  200  includes the first surface  210  fronting onto the air flow path S. The first surface  210  is inclined downward from the second wall surface  32  toward the first wall surface  31 , that is, from the air flow path S toward the room. The blow-out unit  1  changes the first air flow direction F 1  of air flowing toward the blow-out port P through the air flow path S, to the second air flow direction F 21  or F 22  in accordance with the turning angle of the plate member  10  and the inclination angle of the first surface  210  of the guide portion  200 . The blow-out unit  1  is also configured to change the second air flow direction of air blown out through the blow-out port P, by changing the turning angle of the plate member  10 . 
     The blow-out unit  1  according to one or more embodiments is thus capable of easily controlling the air flow direction with this simple configuration. 
     (4-2) 
     The plate member  10  has a substantially rectangular shape. As illustrated in  FIG.  4   , the plate member  10 , which is in the position that covers the blow-out port P, includes the first end  11  (the first side  11   a ) located near the guide portion  200 , the second end  12  located near the first wall surface  31 , and the rotating shaft  15 . The rotating shaft  15  is located nearer to the second end  12  than to the first end  11 . The distance between the rotating shaft  15  and the second end  12  is equal to or less than one-third of the length L of the plate member (i.e., the distance between the first end  11  and the second end  12 ). In other words, the rotating shaft  15  is located between the first wall surface  31  and a straight line that passes a point corresponding to one-third of the length L of the plate member  10  from the second end  12  and extends perpendicularly to the blow-out port P. 
     Air is blown out through the blow-out port P in a single spot between the plate member  10  and the guide portion  200 . In other words, there is no gap between the first wall surface  31  and the plate member  10 , through which air is blown out. There is also no gap between the guide portion  200  and the second wall surface  32 , through which air is blown out. 
     Air is thus blown out toward the room  3  through the clearance between the first surface  101  of the plate member  10  and the first surface  210  of the guide portion  200 . 
     The blow-out unit  1  according to the first embodiments is thus capable of easily controlling the air flow direction with this simple configuration. 
     (4-3) 
     The first surface  210  of the guide portion  200  is inclined such that air flowing through the air flow path S in the first air flow direction F 1  parallel with the first wall surface  31  or the second wall surface  32  collides with the first surface  210  of the guide portion  200 . The inclination angle of the first surface  210  falls within the range from 20° or more to 65° or less relative to the first air flow direction F 1 . 
     The angular change from the first air flow direction F 1  to the second direction decreases as the turning angle of the plate member  10 , which turns from the blow-out port P (the horizontal) toward the air flow path S, increases. 
     (4-4) 
     In the first embodiments, the length L of the plate member  10  and the length W of the blow-out port P in the direction from the first end  11  to the second end  12  (i.e., the width of the air flow path) satisfy the relation of W/4&lt;L&lt;W/2. The length L of the plate member  10  is shorter than the length W-L of the guide portion  200 . 
     (4-5) 
     The blow-out unit  1  also includes the chamber box  30  defining a part of the air flow path S. The chamber box  30  is placed on the attic or behind the sidewall. The chamber box  30  includes the first wall surface  31  located near the plate member  10  and the second wall surface  32  located near the guide portion  200 . The chamber box  30  has the opening serving as the blow-out port P. In the opening, the plate member  10  and the guide portion  200  are placed. 
     (5) Modifications 
     (5-1) Modification 1A 
     In the blow-out unit  1  according to the first embodiments, the rotating shaft  15  of the plate member  10  may be provided separately from the plate member  10 . The rotating shaft  15  is not necessarily located between a plane which is an extension of the first surface  101  of the plate member  10  and a plane which is an extension of the second surface  102  of the plate member  10 . 
     As illustrated in  FIG.  6   , a blow-out unit  1   a  according to Modification 1A is equal in configuration to the blow-out unit  1  according to the first embodiments except that a rotating shaft  15   a  is provided separately from a plate member  10   p,  and a first surface  210  and a second surface  220  of a guide portion  200   p  are in contact with each other. 
     In the example of  FIG.  6    (a sectional view), in the blow-out unit  1   a  according to Modification 1A, the plate member  10   p  includes a first end  11  on a first side, and a second end  12  abutting on a first wall surface  31  of an air flow path S. A rotating fitting is fixed to the plate member  10   p  and the first wall surface  31 . The rotating fitting includes the rotating shaft  15   a  on which the plate member  10   p  turns. The rotating shaft  15   a  of the rotating fitting is rotatable by a motor or manually. 
     (5-2) Modification 1B 
     A blow-out unit according to Modification 1B is equal in configuration to the blow-out unit  1  according to the first embodiments except that the blow-out unit according to Modification 1B does not include the motor and the control unit each described in the first embodiments. In the blow-out unit  1  according to Modification 1B, a turning angle of a plate member  10  is unchanged under normal circumstances. In changing the turning angle, the turning angle is changed manually. 
     The blow-out unit according to Modification 1B is used in a situation in which there is no necessity to constantly change an air flow direction. 
     (5-3) Modification 1C 
     In the blow-out unit  1  according to the first embodiments, air is blown out through the blow-out port P in a single spot between the plate member  10  and the guide portion  200 . According to Modification 1C, air is blown out in two spots. 
     As illustrated in  FIGS.  7 A to  7 C , a blow-out unit  1   c  according to Modification 1C includes two plate members  10   a  and  10   b,  a guide portion  200   a,  and a chamber box  30   c  defining a blow-out port P. The plate members  10   a  and  10   b  and the guide portion  200   a  are placed in the blow-out port P. The plate member  10   a  and the plate member  10   b  are placed with the guide portion  200   a  interposed therebetween such that their longitudinal directions are parallel with each other. A first blow-out port P 1  through which air is blown out is defined between the plate member  10   a  and the guide portion  200   a.  A second blow-out port P 2  through which air is blown out is defined between the plate member  10   b  and the guide portion  200   a.  The guide portion  200   a  includes a first surface  210   a  located near the plate member  10   a,  and a first surface  210   b  located near the plate member  10   b.  The guide portion  200   a  is fixed at its longitudinal two ends to the chamber box  30   c.  As illustrated in  FIGS.  7 A and  7 B , each of the first surface  210   a  and the first surface  210   b  is a curved surface that is recessed downward from an air flow path S toward a room  3 . Each of the first surface  210   a  and the first surface  210   b  may alternatively be a flat surface. The first surface  210   a  is inclined downward from the air flow path S toward the room  3  in a direction from a center of the guide portion  200   a  toward the plate member  10   a,  as seen in a section taken along a direction perpendicular to the blow-out port P and from the plate member  10   a  to the plate member  10   b  (hereinafter, this section is referred to as a section Y). The first surface  210   b  is inclined downward from the air flow path S toward the room  3  in a direction from the center of the guide portion  200   a  toward the plate member  10   b,  as seen in the section Y. In other words, the center of the guide portion  200   a  as seen in the section Y, that is, a portion between the first surface  210   a  and the first surface  210   b  protrudes upward from the blow-out ports P 1  and P 2  toward the air flow path S. The plate member  10   a  and the plate member  10   b  turn in opposite directions from the blow-out port P toward the air flow path S. The blow-out unit  1   c  is equal in configuration to the blow-out unit  1  according to the first embodiments except the configuration described above. 
     Air supplied to the air flow path S flows through the air flow path S in a first air flow direction F 1 . The air is then divided into the air flowing toward the first blow-out port P 1  and the air flowing toward the second blow-out port P 2 . Thus, the air is blown out toward the room  3  through the first blow-out port P 1 . In addition, the air is blown out toward the room  3  through the second blow-out port P 2 . In the first blow-out port P 1 , a second air flow direction F 23   a  which is a blow-out direction changes by a turn of the plate member  10   a.  An angular change from the first air flow direction F 1  to the second air flow direction F 23   a  decreases as the turning angle of the plate member  10   a  relative to the horizontal increases. In other words, the angle of the second air flow direction F 23   a  relative to the horizontal increases. Likewise, in the second blow-out port P 2 , a second air flow direction F 23   b  which is a blow-out direction changes by a turn of the plate member  10   b.  An angular change from the first air flow direction F 1  to the second air flow direction F 23   b  decreases as the turning angle of the plate member  10   b  relative to the horizontal increases. In other words, the angle of the second air flow direction F 23   b  relative to the horizontal increases. 
     In the blow-out unit  1   c  according to Modification 1C, the second air flow direction F 23   a  and the second air flow direction F 23   b  are controllable independently. In other words, the turning angle of the plate member  10   a  and the turning angle of the plate member  10   b  are controllable independently. In addition, both the blow-out port P 1  and the blow-out port P 2  may be opened at the same time. Alternatively, both the blow-out port P 1  and the blow-out port P 2  may be closed at the same time. Still alternatively, one of the blow-out port P 1  and the blow-out port P 2  may be opened while the other may be closed. 
     (5-4) Modification 1D 
     In the blow-out unit  1  according to the first embodiments, air is blown out through the blow-out port P in a single spot between the plate member  10  and the guide portion  200 . According to Modification 1D, air is blown out in four spots. 
     As illustrated in  FIGS.  8  to  10   , a blow-out unit  1   d  according to Modification 1D includes four plate members  10   a  to  10   d,  a guide portion  200   b,  and a chamber box  30   d  defining a blow-out port P. The plate members  10   a  to  10   d  and the guide portion  200   b  are placed in the blow-out port P. The plate member  10   a  and the plate member  10   c  are placed with the guide portion  200   b  interposed therebetween such that their longitudinal directions are parallel with each other. The plate member  10   b  and the plate member  10   d  are placed with the guide portion  200   b  interposed therebetween such that their longitudinal directions are parallel with each other. The longitudinal direction of each of the plate member  10   a  and the plate member  10   c  is perpendicular to the longitudinal direction of each of the plate member  10   b  and the plate member  10   d.  The plate members  10   a  to  10   d  are placed to surround four sides of a second surface of the guide portion  200   b  having a rectangular shape, with the blow-out unit  1   d  seen from below. Four blow-out ports P 1  to P 4 , through which air is blown out, are respectively defined between the plate members  10   a  to  10   d  and the guide portion  200   b.  The guide portion  200   b  includes a first surface  210   a  located near the plate member  10   a,  a first surface  210   b  located near the plate member  10   b,  a first surface  210   c  located near the plate member  10   c,  and a first surface  210   d  located near the plate member  10   d.  Each of the first surfaces  210   a  to  210   d  is inclined downward from an air flow path S toward a room  3  in a direction from a center of the guide portion  200   b  toward the plate member  10   a.  The guide portion  200   b  may be fixed at its center to an inner upper surface of the chamber box  30   d  with a support. As illustrated in  FIG.  8   , each of the first surfaces  210   a  to  210   d  is a flat surface. Each of the first surfaces  210   a  to  210   d  may alternatively be a curved surface recessed downward from the air flow path S toward the room  3 . The blow-out unit  1   d  is equal in configuration to the blow-out unit  1  according to the first embodiments except the configuration described above. 
     In the blow-out unit  1   d  according to Modification 1D, air supplied to the air flow path S flows through the air flow path S in a first air flow direction F 1 , branches to the blowout ports P 1  to P 4 , and blow out into the room  3 . In the blow-out ports P 1  to P 4 , second air flow directions F 24   a  each of which is a blow-out direction change by turns of the plate members  10   a  to  10   d,  respectively. Angular changes from the first air flow direction F 1  to the second air flow directions F 24   a  to F 24   d  decrease as the turning angles of the plate members  10   a  to  10   d  relative to the horizontal increase. In other words, the angles of the second air flow directions F 24   a  to F 24   d  relative to the horizontal increase. In the blow-out unit  1   d  according to Modification 1D, the second air flow directions, which are directions of air blown out toward the room through the blow-out ports P 1  to P 4 , are controllable independently of one another. In other words, the turning angles of the plate members  10   a  to  10   d  are controllable independently of one another. In addition, all the blow-out ports P 1  to P 4  may be opened at the same time. Alternatively, all the blow-out ports P 1  to P 4  may be closed at the same time. Still alternatively, some of the blow-out ports P 1  to P 4  may be opened while the others may be closed. 
     (5-5) Modification 1E 
     A blow-out unit  1   e  according to Modification 1E is a constituent element of an air conditioning apparatus. The air conditioning apparatus is configured to carry out air conditioning operations including a heating operation, a cooling operation, a dehumidifying operation, a humidifying operation, and the like for a room. The air conditioning apparatus includes a fan, a heat exchanger, and the like in addition to the blow-out unit. Since an air flow path S is defined inside the air conditioning apparatus, the blow-out unit  1   e  does not include the chamber box  30  described in the first embodiments. The blow-out unit  1   e  is different in this respect from the blow-out unit  1  according to the first embodiments. A blow-out port P is a blow-out port formed in the air conditioning apparatus. The blow-out unit  1   e  does not necessarily include the panel  33  described in the first embodiments. The blow-out unit  1   e  is equal in configuration to the blow-out unit  1  according to the first embodiments except the configuration described above. 
     Second Embodiments 
     (6) Configuration of Blow-Out Unit  100   
     A blow-out unit  100  is placed at a blow-out port P of an air flow path S through which air is blown out toward a room  3 , and is configured to blow out, toward the room  3 , air supplied thereto through the air flow path S. As used herein, air to be supplied to the blow-out unit  1  involves, for example, outside air, and heated, cooled, dehumidified, or humidified air in the room  3 . The blow-out port P is bored in a ceiling or a wall of the room. The blow-out unit  100  is located nearer to the air flow path S than to the blow-out port P and is placed on an attic or behind a sidewall. 
     The blow-out unit  100  is described with reference to the drawings.  FIG.  11    is a perspective view illustrating the blow-out unit  100  placed on the attic, the blow-out unit  100  seen from below.  FIG.  12    is a vertical sectional view schematically illustrating a flow of air in the blow-out unit  100 .  FIG.  13 A  is a vertical sectional view illustrating the blow-out unit  100  in which a first plate member  10  and a second plate member  20  are in a first state.  FIG.  13 B  is a vertical sectional view illustrating the blow-out unit  100  in which the first plate member  10  and the second plate member  20  are in a second state.  FIG.  16    is a control block diagram illustrating the blow-out unit  100 . 
     The blow-out unit  100  includes the first plate member  10 , the second plate member  20 , a chamber box  30 , a panel  33 , a control unit  40 , a first motor  41 , and a second motor  42 . The chamber box  30  has a box shape and includes an intake port connected to a duct, and a blow-out port through which air is blown out. A configuration of the chamber box  30  will be described later. The blow-out unit  100  is placed on the attic such that the blow-out port of the chamber box  30  is aligned over an opening in the ceiling  2  of the room. The chamber box  30  defines a part of the air flow path S. The blow-out port of the chamber box  30  serves as the blow-out port P of the air flow path S. The first plate member  10  and the second plate member  20  are placed in the blow-out port P. In the second embodiments, the blow-out port P has a rectangular shape as seen from below. The panel  33  is placed on the ceiling from below so as to cover an outer periphery of the blow-out port P in the ceiling. The blow-out unit  100  blows out air supplied thereto through the chamber box  30 , toward the room  3  by a turn of the first plate member  10  and a turn of the second plate member  20 . 
     The first plate member  10  and the second plate member  20  correspond to a pair of plate members to be placed in the blow-out port P of the chamber box  30 . One of the pair of plate members is referred to as a first plate member, and the other is referred to as a second plate member. 
     The first plate member  10  is a rectangular plate having a predetermined thickness. The first plate member  10  is placed such that a surface thereof is flush with the ceiling. The first plate member  10  includes a first surface  101  fronting onto the room and a second surface  102  fronting onto the air flow path S. The first plate member  10  includes a first side  11   a  extending longitudinally and facing the second plate member  20 , and a second side  12   a  extending in parallel with the first side  11   a  and facing a first wall surface  30   a  of the chamber box  30 . The first plate member  10  is substantially identical in longitudinal length with the blow-out port P. As illustrated in  FIG.  13 A , as seen in a section taken along a direction perpendicular to the blow-out port P and from the first plate member  10  to the second plate member  20  (hereinafter, this section is referred to as a section X), the first plate member  10  includes a first end  11  located near the second plate member  20  and a second end  12  located near the first wall surface  30   a  of the chamber box  30  (i.e., the air flow path S). The first end  11  is located on the first side  11   a  of the first plate member  10 . The second end  12  is located on the second side  12   a  of the first plate member  10 . 
     The shape of the first plate member  10  is appropriately changeable in accordance with the shape of the blow-out port P. The first plate member  10  may have a square shape in addition to the rectangular shape. The first plate member  10  may be chamfered. The first plate member  10  has a thickness that is not necessarily uniform. The first plate member  10  may have a thickness that gradually decreases from a center of the first plate member  10  toward ends on the four sides of the first plate member  10 . 
     The first plate member  10  includes a first rotating shaft  15  disposed near the second end  12 . A distance between the first rotating shaft  15  and the second end  12  is equal to or less than one-third of a distance between the first end  11  and the second end  12  of the first plate member  10 . Further, the distance between the first rotating shaft  15  and the second end  12  may be equal to or less than a half of the thickness of the first plate member  10 . This configuration enables a reduction in volume of air flowing through a gap formed between the first plate member  10  and the wall surface of the chamber box  30  when the first plate member  10  turns. This configuration also inhibits the second end  12  from protruding from the blow-out port P toward the room when the first plate member  10  turns. The first plate member  10  is turnable 90° on the first rotating shaft  15 . The first plate member  10  may be configured to turn on the first rotating shaft  15  from 0° toward the air flow path S within an angular range from 45° or more to less than 90°. The first plate member  10  may be configured to turn within any angular range as long as the first plate member  10  is capable of adjusting an air flow direction. 
     As illustrated in  FIG.  13 A , in the first state, the first plate member  10  is in a position that covers the blow-out port P. As illustrated in  FIG.  13 B , in the second state, the first plate member  10  turns on the first rotating shaft  15  so that the first end  11  moves toward the air flow path S. 
     The second plate member  20  is a rectangular plate having a predetermined thickness. The second plate member  20  is placed such that a surface thereof is flush with the ceiling. The second plate member  20  includes a first surface  201  fronting onto the room and a second surface  202  fronting onto the air flow path S. The second plate member  20  includes a first side  21   a  extending longitudinally and facing the first plate member  10 , and a second side  22   a  extending in parallel with the first side  21   a  and facing a second wall surface  30   b  of the chamber box  30 . The second plate member  20  is substantially identical in longitudinal length with the blow-out port P. As illustrated in  FIG.  13 A , the second plate member  20  includes a first end  21  located near the first plate member  10  and a second end  22  located near the second wall surface  30   b  of the chamber box  30  (i.e., the air flow path S) as seen in the section X. 
     The shape of the second plate member  20  is appropriately changeable in accordance with the shape of the blow-out port P. The second plate member  20  may have a square shape in addition to the rectangular shape. The second plate member  20  may be chamfered. The second plate member  20  has a thickness that is not necessarily uniform. The second plate member  20  may have a thickness that gradually decreases from a center of the second plate member  20  toward ends on the four sides of the second plate member  20 . 
     The second plate member  20  includes a second rotating shaft  25  disposed near the second end  22 . A distance between the second rotating shaft  25  and the second end  22  is equal to or less than one-third of a distance between the first end  21  and the second end  22  of the second plate member  20 . Further, the distance between the second rotating shaft  25  and the second end  22  may be equal to or less than a half of the thickness of the second plate member  20 . This configuration enables a reduction in volume of air flowing through a gap formed between the second plate member  20  and the second wall surface  30   b  of the chamber box  30  when the second plate member  20  turns. This configuration also inhibits the second end  22  from protruding from the blow-out port P toward the room when the second plate member  20  turns. The second plate member  20  is turnable 90° on the second rotating shaft  25 . The second plate member  20  may be configured to turn on the second rotating shaft  25  from 0° toward the air flow path S within an angular range from 45° or more to less than 90°. The second plate member  20  may be configured to turn within any angular range as long as the second plate member  20  is capable of adjusting an air flow direction. 
     As illustrated in  FIG.  13 A , in the first state, the second plate member  20  is in a position that covers the blow-out port P. As illustrated in  FIG.  13 B , in the second state, the second plate member  20  turns on the second rotating shaft  25  so that the first end  21  moves toward the air flow path S. 
     As illustrated in  FIGS.  13 A and  13 B , the first plate member  10  turns counterclockwise, so that the first state shifts to the second state. On the other hand, the second plate member  20  turns clockwise, so that the first state shifts to the second state. 
     As illustrated in  FIG.  13 A , when both the first plate member  10  and the second plate member  20  are in the first state, the blow-out port P is closed. At this time, the first end  11  of the first plate member  10  and the first end  21  of the second plate member  20  face each other. In addition, the first surface  101  of the first plate member  10  and the first surface  201  of the second plate member  20  are flush with each other. However, the first surface  101  of the first plate member  10  and the first surface  201  of the second plate member  20  are not necessarily flush with each other. For example, one of the first surface  101  of the first plate member  10  and the first surface  201  of the second plate member  20  may be located nearer to the air flow path S than the other is. 
     When one of or both the first plate member  10  and the second plate member  20  is or are in the second state, the blow-out port P is open. In  FIGS.  12  and  13 B , both the first plate member  10  and the second plate member  20  are in the second state. As illustrated in  FIG.  12   , an air flow direction is changeable by making the turning angle of the first plate member  10  different from the turning angle of the second plate member  20 . In addition, a blow distance D 1  of air is changeable in accordance with the turning angle of the first plate member  10  and the turning angle of the second plate member  20 . 
     The chamber box  30  defines a part of the air flow path S. The chamber box  30  is placed on the attic or behind the sidewall. The chamber box  30  has the box shape and includes the intake port connected to the duct, and the blow-out port through which air is blown out. The intake port may be connected via the duct to an air treatment unit of a ventilation apparatus, an air conditioning apparatus, or the like. The blow-out port is substantially identical in shape with the opening in the ceiling. The chamber box  30  includes four wall surfaces extending perpendicularly to the blow-out port P. The four wall surfaces have ends that define the blow-out port P. The four wall surfaces include the first wall surface  30   a  located near the first plate member  10  and the second wall surface  30   b  located near the second plate member  20  as seen in the section X. The intake port of the chamber box  30  may be formed in an upper portion of the chamber box  30  or may be formed in a sidewall surface of the chamber box  30 . As illustrated in  FIGS.  13 A and  13 B , the intake port is formed in the second wall surface  30   b.  In the second embodiments, the chamber box  30  defines the air flow path S; however, the chamber box  30  is not an essential constituent element. 
     The panel  33  is placed on the ceiling  2  from below so as to cover the outer periphery of the blow-out port P in the ceiling  2 . The panel  33  is a frame having a predetermined thickness. The panel  33  protrudes inwardly from the ceiling so as to partially cover the blow-out port P. The panel  33  covers a part of the second end  12  of the first plate member  10  from below as seen in the section X. The panel  33  also covers a part of the second end  22  of the second plate member  20  from below as seen in the section X. The panel  33  has a surface fronting onto the room, and this surface is located nearer to the room than the first surface  101  of the first plate member  10  and the first surface  201  of the second plate member  20  are. Alternatively, the surface, which fronts onto the room, of the panel  33  may be flush with the first surface  101  of the first plate member  10  and the first surface  201  of the second plate member  20 . The panel  33  may cover only the ceiling. However, the panel  33 , which protrudes inwardly from the ceiling so as to partially cover the blow-out port P, inhibits air from flowing through a gap between the second end  12  of the first plate member  10  and the first wall surface  30   a  of the chamber box  30  and a gap between the second end  22  of the second plate member  20  and the second wall surface  30   b  of the chamber box  30 . The panel  33  covers the blow-out port of the chamber box  30 , the gap between the first plate member  10  and the wall surface of the chamber box  30 , and the gap between the second plate member  20  and the wall surface of the chamber box  30  so as to be invisible from below. The panel  33  therefore improves the appearance of the blow-out unit  100 ; however, the panel  33  is not an essential constituent element. 
     The first motor  41  allows the first plate member  10  to turn. The second motor  42  allows the second plate member  20  to turn. In other words, the first plate member  10  and the second plate member  20  are turnable independently. Each of the first motor  41  and the second motor  42  may be a stepping motor. Each of the first motor  41  and the second motor  42  may be placed in or outside the chamber box  30 . 
       FIG.  16    is the control block diagram illustrating the blow-out unit  100 . The control unit  40  is configured to control the first motor  41  and the second motor  42 . The control unit  40  is a computer. The control unit  40  includes a processor and a memory. The control unit  40  may be a microcomputer. The control unit  40  may be placed anywhere. The control unit  40  may be configured to control a plurality of blow-out units  100  at the same time. The control unit  40  may be used together with a control unit configured to control constituent elements of another air conditioning apparatus. For example, the control unit  40  may be used together with a control unit for a heat exchanger configured to heat or cool air to be supplied to the room  3 . The control unit  40  may perform control in cooperation with the control unit for such a constituent element. 
     The control unit  40  may perform control in accordance with an instruction from a remote controller operated by a user. 
     (7) Control of Blow Distance D 1  of Air to be Blown Out by Blow-Out Unit  100   
     A simulation was performed on the blow-out unit  100  for examining how the blow distance D 1  of air blown out toward the room  3  through the blow-out port P changes by changing the turning angle of the first plate member  10  and the turning angle of the second plate member  20 . The simulation was performed under conditions that a system is entirely set in an isothermal field and a volume of air to be blown out is 10 m 3 /min.  FIGS.  14 A to  14 C  illustrate results of the simulation. In  FIGS.  14 A to  14 C , the upper sides each illustrate the turning angle of the first plate member  10  and the turning angle of the second plate member  20 , and the lower sides each illustrate an area where an air velocity is equal to or more than 1 m/s. It is understood from  FIGS.  14 A to  14 C  that in this simulation, the turning angle of the first plate member  10  is set to be equal to the turning angle of the second plate member  20 . In other words, the first plate member  10  and the second plate member  20  turn symmetrically with respect to a center line. 
     In  FIG.  14 A , the turning angle of each of the first plate member  10  and the second plate member  20  is set at 30° relative to the horizontal. In this case, air blown out through the blow-out port P in the ceiling  2  reaches a floor of the room  3 . The blow distance D 1  is 2.6 m. In  FIG.  14 B , the turning angle of each of the first plate member  10  and the second plate member  20  is set at 50° relative to the horizontal. The blow distance D 1  of air blown out in this case is 2.1 m. In  FIG.  14 C , the turning angle of each of the first plate member  10  and the second plate member  20  is set at 65° relative to the horizontal. The blow distance D 1  of air blown out in this case is 1.6 m. It is understood from  FIGS.  14 A to  14 C  that the blow distance D 1  decreases as the turning angle of each of the first plate member  10  and the second plate member  20  increases. 
     (8) Control of Air Flow Direction of Air to be Blown Out by Blow-Out Unit  100   
     A simulation was performed on the blow-out unit  100  for examining how the air flow direction of air blown out toward the room  3  through the blow-out port P changes by changing the turning angle of the first plate member  10  and the turning angle of the second plate member  20 . The simulation was performed under conditions that a system is entirely set in an isothermal field and a volume of air to be blown out is 10 m 3 /min.  FIGS.  15 A to  15 E  illustrate results of the simulation. In  FIGS.  15 A to  15 E , the upper sides each illustrate the turning angle of the first plate member  10  and the turning angle of the second plate member  20 , and the lower sides each illustrate an area where an air velocity is equal to or more than 1 m/s. In this simulation,  FIG.  15 A to  15 D  each illustrate a case where the turning angle of the first plate member  10  is set to be smaller than the turning angle of the second plate member  20 . The air flow direction of air blown out through the blow-out port P is tilted toward the second plate member  20 .  FIG.  15 E  illustrates a case where the turning angle of the first plate member  10  is set to be equal to the turning angle of the second plate member  20 . The air flow direction of air blown out through the blow-out port P is the vertical direction. 
     In  FIG.  15 A , the turning angle of the first plate member  10  is set at 15° relative to the horizontal, and the turning angle of the second plate member  20  is set at 52° relative to the horizontal. The air flow direction (i.e., an air current angle) is tilted 20° relative to the horizontal toward the second plate member  20 . In  FIG.  15 B , the turning angle of the first plate member  10  is set at 16° relative to the horizontal, and the turning angle of the second plate member  20  is set at 50° relative to the horizontal. The air flow direction (i.e., the air current angle) is tilted 30° relative to the horizontal toward the second plate member  20 . In  FIG.  15 C , the turning angle of the first plate member  10  is set at 30° relative to the horizontal, and the turning angle of the second plate member  20  is set at 52° relative to the horizontal. The air flow direction (i.e., the air current angle) is tilted 45° relative to the horizontal toward the second plate member  20 . In  FIG.  15 D , the turning angle of the first plate member  10  is set at 35° relative to the horizontal, and the turning angle of the second plate member  20  is set at 52° relative to the horizontal. The air flow direction (i.e., the air current angle) is tilted 65° relative to the horizontal toward the second plate member  20 . In  FIG.  15 E , each of the turning angle of the first plate member  10  and the turning angle of the second plate member  20  is set at 52° relative to the horizontal. The air flow direction (i.e., the air current angle) is the vertical direction. 
     As described in (2) or (3) above, the air flow direction of air blown out toward the room  3  depends on the turning angle of the first plate member  10  and the turning angle of the second plate member  20 . The memory of the control unit  40  stores, in advance, the turning angle of the first plate member  10 , the turning angle of the second plate member  20 , and the air flow direction of air blown out toward the room  3 , each obtained by a preliminary test. In conditioning air in the room, the control unit  40  controls the turning angle of the first plate member  10  and the turning angle of the second plate member  20 , using the data stored in the memory in order to achieve a predetermined air flow direction of air blown out blown out toward the room  3 . 
     (9) Features 
     (9-1) 
     The blow-out unit  100  according to the second embodiments is placed at the blow-out port P of the air flow path S through which air is blown out toward the room  3 , and is configured to blow out, toward the room  3 , air supplied thereto through the air flow path S. The blow-out unit  100  includes the first plate member  10  and the second plate member  20 . The first plate member  10  is configured to turn on the first rotating shaft  15  so that the first state in which the first plate member  10  is in the position that covers the blow-out port P shifts to the second state in which the first plate member  10  is on the air flow path S. Likewise, the second plate member  20  is configured to turn on the second rotating shaft  25  so that the first state in which the second plate member  20  is in the position that covers the blow-out port P shifts to the second state in which the second plate member  20  is on the air flow path S. In the first state, the first side  11   a  located away from the first rotating shaft  15  in the first plate member  10  faces the first side  21   a  located away from the second rotating shaft  25  in the second plate member  20 . 
     With this configuration, the blow-out unit  100  according to the second embodiments is capable of changing the air flow direction and blow distance D 1  of air blown out through the blow-out port P, by changing the turning angle of the first plate member  10  and the turning angle of the second plate member  20 . 
     (9-2) 
     The first plate member  10  has a substantially rectangular shape. As illustrated in  FIG.  13 A , the first plate member  10  includes, in the first state, the first side  11   a  located near the second plate member  20 , the second side  12   a  located near the first wall surface  30   a  of the air flow path S (or the chamber box  30 ), and the first rotating shaft  15 . The first rotating shaft  15  is located nearer to the second side  12   a  than to the first side  11   a . The distance between the first rotating shaft  15  and the second side  12   a  is equal to or less than one-third of the distance between the first side  11   a  and the second side  12   a  of the first plate member  10 . In other words, the first rotating shaft  15  is located between the first wall surface  30   a  and a straight line that passes a point corresponding to one-third of the length of the first plate member  10  from the second side  12   a  and extends perpendicularly to the blow-out port P. 
     Likewise, the second plate member  20  has a substantially rectangular shape. As illustrated in  FIG.  13 A , the second plate member  20  includes, in the first state, the first side  21   a  located near the first plate member  10 , the second side  22   a  located near the second wall surface  30   b  of the air flow path S (or the chamber box  30 ), and the second rotating shaft  25 . The second rotating shaft  25  is located nearer to the second side  22   a  than to the first side  21   a.  The distance between the second rotating shaft  25  and the second side  22   a  is equal to or less than one-third of the distance between the first side  21   a  and the second side  22   a  of the second plate member  20 . In other words, the second rotating shaft  25  is located between the second wall surface  30   b  and a straight line that passes a point corresponding to one-third of the length of the second plate member  20  from the second side  22   a  and extends perpendicularly to the blow-out port P. 
     Air is blown out through the blow-out port P in a single air blow-out portion between the first plate member  10  and the second plate member  20 . In other words, there is no gap between the first plate member  10  and the first wall surface  30   a,  through which air is blown out. There is also no gap between the second plate member  20  and the second wall surface  30   b,  through which air is blown out. 
     With this configuration, the blow-out port P according to the second embodiments is capable of easily controlling the air flow direction and blow distance D 1  of air. 
     (9-3) 
     In the blow-out unit  100  according to the second embodiments, the first surface  101  of the first plate member  10  and the first surface  201  of the second plate member  20  are substantially flush with the ceiling  2  in the first state. This configuration improves design since the blow-out unit  100  is inconspicuous even when being mounted to the ceiling  2 . 
     (9-4) 
     The blow-out unit  100  according to the second embodiments also includes the chamber box  30  defining a part of the air flow path S. The chamber box  30  is placed on the attic or behind the sidewall. The chamber box  30  includes the first wall surface  30   a  located near the first plate member  10 , and the second wall surface  30   b  located near the second plate member  20 . The chamber box  30  has the opening serving as the blow-out port P. In the opening, the first plate member  10  and the second plate member  20  are placed. 
     (9-5) 
     In the first state, the first plate member  10  is flush with the second plate member  20 , so that the blow-out port P is closed. In other words, the first side  11   a  of the first plate member  10  is parallel with the first side  21   a  of the second plate member  20 . In addition, there is a small gap between the first side  11   a  of the first plate member  10  and the first side  21   a  of the second plate member  20 . 
     Therefore, the blow-out port P can be opened and closed by switching between the first state and the second state of each of the first plate member  10  and the second plate member  20 . 
     (9-6) 
     The blow-out unit  100  according to the second embodiments also includes the control unit  40 , the first motor  41 , and the second motor  42 . 
     The first motor  41  allows the first plate member  10  to turn. The second motor  42  allows the second plate member  20  to turn. The control unit  40  is configured to control the first motor  41  and the second motor  42 . The control unit  40  controls the first motor  41  and the second motor  42  to respectively adjust the first plate member  10  and the second plate member  20  to appropriate angles. The control unit  40  thus controls the air flow direction and blow distance D 1  of air. 
     (10) Modifications 
     (10-1) Modification 2A 
     A blow-out unit according to Modification 2A is equal in configuration to the blow-out unit  100  according to the second embodiments except that the blow-out unit according to Modification 2A does not include the motor and the control unit each described in the second embodiments. In the blow-out unit  100  according to Modification 2A, a turning angle of a first plate member  10  and a turning angle of a second plate member  20  are unchanged under normal circumstances. In changing the turning angles, the turning angles are changed manually. 
     The blow-out unit according to Modification 2A is used in a situation in which there is no necessity to constantly change an air flow direction. 
     (10-2) Modification 2B 
     In the blow-out unit  100  according to the second embodiments, air is blown out through the blow-out port P in a single spot between the first plate member  10  and the second plate member  20 . According to Modification 2B, air is blown out in two spots. As illustrated in  FIG.  17   , a blow-out unit  100   a  according to Modification 2B includes first plate members  10   x  and  10   y,  second plate members  20   x  and  20   y,  and a chamber box  30   x  defining a blow-out port P. The first plate members  10   x  and  10   y  and the second plate members  20   x  and  20   y  are placed in the blow-out port P. The first plate member  10   x  is juxtaposed to the second plate member  20   x  in a direction perpendicular to the longitudinal direction of the blow-out port P. The first plate member  10   y  is juxtaposed to the second plate member  20   y  in a direction perpendicular to the longitudinal direction of the blow-out port P. The first plate member  10   x  is juxtaposed to the first plate member  10   y  in the longitudinal direction of the blow-out port P. The second plate member  20   x  is juxtaposed to the second plate member  20   y  in the longitudinal direction of the blow-out port P. A first blow-out port P 1  through which air is blown out is defined between the first plate member  10   x  and the second plate member  20   x.  A second blow-out port P 2  through which air is blown out is defined between the first plate member  10   y  and the second plate member  20   y.  The first plate members  10   x  and  10   y  and the second plate members  20   x  and  20   y  are similar in configuration and movement to the first plate member  10  and the second plate member  20  described in the second embodiments. 
     A panel  33   a  includes a portion located between the first plate member  10   x  and the second plate member  20   x  and a portion located between the first plate member  10   y  and the second plate member  20   y.  These portions extend in a direction perpendicular to the longitudinal direction of the blow-out port P. The blow-out unit  100   a  is equal in configuration to the blow-out unit  100  according to the second embodiments except the configuration described above. 
     In the blow-out unit  100   a  according to Modification 2B, an air flow direction and a blow distance D 1  of air to be blown out through the first blow-out port P 1  are controllable by controlling a turning angle of the first plate member  10   x  and a turning angle of the second plate member  20   x.  Likewise, an air flow direction and a blow distance D 1  of air to be blown out through the second blow-out port P 2  are controllable by controlling a turning angle of the first plate member  10   y  and a turning angle of the second plate member  20   y.    
     The air flow direction and blow distance D 1  of air to be blown out through the first blow-out port P 1  are controllable to be substantially identical with the air flow direction and blow distance D 1  of air to be blown out through the second blow-out port P 2 , in such a manner that the turning angle of the first plate member  10   x  is controlled to be identical with the turning angle of the first plate member  10   y  while the turning angle of the second plate member  20   x  is controlled to be identical with the turning angle of the second plate member  20   y.    
     In addition, the air flow direction and blow distance D 1  of air to be blown out through the first blow-out port P 1  are controllable to be different from the air flow direction and blow distance D 1  of air to be blown out through the second blow-out port P 2 , in such a manner that one of or both the turning angles of the first plate member  10   x  and first plate member  10   y  and the turning angles of the second plate member  20   x  and second plate member  20   y  are made different from each other. 
     In  FIG.  17   , a ceiling  2 , the panel  33   a,  the first plate members  10   x  and  10   y,  and surfaces, each of which fronts onto the room, of the second plate members  20   x  and  20   y  are substantially flush with each other. This configuration ensures excellent appearance of the blow-out unit  100   a.    
     (10-3) Modification 2C 
     In the blow-out unit  100  according to the second embodiments, the first rotating shaft  15  of the first plate member  10  may be provided separately from the first plate member  10 , and the second rotating shaft  25  of the second plate member  20  may be provided separately from the second plate member  20 . The first rotating shaft  15  is not necessarily located between a plane which is an extension of the first surface  101  of the first plate member  10  and a plane which is an extension of the second surface  102  of the first plate member  10 . The second rotating shaft  25  is not necessarily located between a plane which is an extension of the first surface  201  of the second plate member  20  and a plane which is an extension of the second surface  202  of the second plate member  20 . 
     As illustrated in  FIG.  18   , a blow-out unit  100   b  according to Modification 2C is equal in configuration to the blow-out unit  100  according to the second embodiments except that a first rotating shaft  15  is provided separately from a first plate member  10  and a second rotating shaft  25  is provided separately from a second plate member  20 . 
     In the example of  FIG.  18    (a sectional view), in the blow-out unit  100   b  according to Modification 2C, the first plate member  10  includes a first end  11  on a first side, and a second end  12  facing a first wall surface  30   a  of an air flow path S. A rotating fitting is fixed to the first plate member  10  and the first wall surface  30   a.  The rotating fitting includes a first rotating shaft  15  on which the first plate member  10  turns. The second plate member  20  includes a first end  21  on a first side, and a second end  22  facing a second wall surface  30   b  of the air flow path S. A rotating fitting is fixed to the second plate member  20  and the second wall surface  30   b.  The rotating fitting includes a second rotating shaft  25  on which the second plate member  20  turns. Each of the first rotating shaft  15  of the rotating fitting and the second rotating shaft  25  of the rotating fitting is rotatable by a motor or manually. 
     Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present disclosure. Accordingly, the scope of the disclosure should be limited only by the attached claims. 
     REFERENCE SIGNS LIST 
       1 ,  1   a ,  1   c ,  1   d ,  100 ,  100   a : blow-out unit 
       2 : ceiling 
       3 : room 
       10 ,  10   x,    10   y : first plate member 
       11   a : first side of first plate member 
       12   a : second side of first plate member 
       11 : first end of first plate member 
       12 : second end of first plate member 
       101 : first surface of first plate member 
       102 : second surface of first plate member 
       15 : first rotating shaft 
       20 ,  20   x,    20   y : second plate member 
       21   a : first side of second plate member 
       22   a : second side of second plate member 
       21 : first end of second plate member 
       22 : second end of second plate member 
       201 : first surface of second plate member 
       202 : second surface of second plate member 
       25 : second rotating shaft 
       200 ,  200   a,    200   b,    200   p : guide portion 
       210 : first surface 
       30 : chamber box 
       30   a,    31 : first wall surface 
       30   b,    32 : second wall surface 
       33 ,  33   a : panel below (chamber box) 
     P, P 1 , P 2 : blow-out port 
     S: air flow path 
     F 1 : first air flow direction 
     F 21 , F 22 : second air flow direction 
     L: length of plate member 
     D: thickness of plate member 
     D 1 : blow distance 
     W: width of air flow path (length of blow-out port) 
     W—L: width of guide portion 
     PATENT LITERATURE 
     Patent Literature 1: JP 2007-155309 A