Patent Publication Number: US-10767874-B2

Title: Ceiling-embedded air conditioner

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Japanese Patent Application No. 2014-209324 filed with the Japan Patent Office on Oct. 10, 2014, the entire content of which is hereby incorporated by reference. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a ceiling-embedded air conditioner. More specifically, the present disclosure relates to a ceiling-embedded air conditioner that suppresses swirling airflows generated on the back surface of a bell-mouth by rotation of a turbo fan. 
     2. Description of the Related Art 
     The ceiling-embedded air conditioner has a casing body including a heat exchanger and a blower (turbo fan). The casing body is embedded in a space formed between a ceiling slab and a ceiling panel. A flat square decorative panel is attached to the lower surface of the casing body. The decorative panel has an air inlet and an air outlet. 
     In the configuration described in JP-A-2012-2165, the casing body is a cuboid in shape. The turbo fan is disposed at the center of the casing body. The heat exchanger is disposed to surround the outer periphery of the turbo fan. A bell-mouth is provided between the air inlet and the turbo fan. The bell-mouth guides the air, which is taken into the casing body from the air inlet, to the inside of the turbo fan. 
     The turbo fan has a main plate, a shroud, and a plurality of blades. The main plate has a hub, to which a rotation shaft is fixed, at the center. The shroud is disposed to be opposite to the direction of axis of the rotation shaft relative to the main plate. The plurality of blades is disposed between the main plate and the shroud. The shroud has an opening at the center through which the bell-mouth is partially inserted into the turbo fan. 
     The bell-mouth has a base portion and a suction guide portion. The base portion is formed in a square shape corresponding to the shape of the air inlet. The suction guide portion is formed in a trumpet shape from the center of the base portion toward the inside of the turbo fan. As the turbo fan is driven, the air is sucked from the air inlet through the bell-mouth to the inside of the turbo fan (refer to JP-A-2012-2165, FIG. 2). 
     The air blown from the turbo fan is directed to the surrounding heat exchanger, and is heat-exchanged with a refrigerant through the spaces between heat-radiation fins in the heat exchanger. After that, the air is blown from the air outlet into the room through a blowing path. The blowing range of the turbo fan in the axial direction depends on the axial height of the outlet. In general, the axial height of the outlet is set to be lower than the height of the heat exchanger. This causes unevenness in wind speed distribution at the portion of the heat exchanger opposed to the outlet and the portion of the heat exchanger separated from the outlet. The unevenness results in unbalanced heat exchange. 
     As another problem, there is high blowing resistance at the back surface side of the blowing path opposite to the suction guide portion side of the bell-mouth. Accordingly, part of the air leaks from the gap formed between the bell-mouth and the turbo fan into the inside of the turbo fan (recirculation). Therefore, the air not passing through the heat exchanger is retained on the back surface side of the bell-mouth. As the turbo fan rotates, the retained air swirls along the back surface of the bell-mouth opposite to the air suction surface on the air inlet side. That is, swirling airflows are generated. The generation of the swirling airflows leads to reduction in the amount of wind flowing into the heat exchanger. This results in an unsmooth flow of air with lower heat-exchange efficiency. 
     According to the technique described in JP-A-2007-100548, radial ribs are provided on the back surface of the shroud to suppress loss of air blow. Accordingly, the air approaching the gap formed between the bell-mouth and the shroud is forcibly pushed back to the outside in radial direction. 
     However, the method described in JP-A-2007-100548 does not solve the swirling airflow problem and thus is less effective in preventing reduction in heat-exchange efficiency. In addition, providing the ribs may increase wind noise and vibration. 
     SUMMARY 
     A ceiling-embedded air conditioner includes: a ceiling-embedded casing body that has an air suction path at the center of a lower surface and has an air blowoff path around the air suction path; a turbo fan that is disposed inside the casing body; a heat exchanger that is disposed inside the casing body on an outer peripheral side of the turbo fan; a bell-mouth that guides air sucked from the air suction path toward the inside of the turbo fan; and a rectifier that is provided on a back surface side of the bell-mouth at the air suction path side opposite to an air suction surface of the bell-mouth, the rectifier suppressing swirling airflows generated by part of air blown from the turbo fan swirling along the back surface of the bell-mouth in the same direction as a rotation direction of the turbo fan. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a casing body of a ceiling-embedded air conditioner according to one embodiment of the present disclosure as seen from the lower side; 
         FIG. 2  is a perspective view of the casing body illustrated in  FIG. 1  from which a decorative panel is removed; 
         FIG. 3  is a cross-sectional view of inner structure of the casing body; 
         FIG. 4A  is a perspective view of a bell-mouth as seen from the front side, and  FIG. 4B  is a perspective view of the bell-mouth as seen from the rear side; 
         FIG. 5A  is a front view of the bell-mouth and  FIG. 5B  is a rear view of the bell-mouth; 
         FIG. 6  is a bottom view illustrating the positional relation between a heat exchanger and an electrical equipment box; 
         FIG. 7  is a cross-sectional view illustrating the mode in which a rectifier is provided on a drain pan side; and 
         FIG. 8  is an illustrative diagram for describing the rectifying effect of the rectifiers provided on the back surface of the bell-mouth. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     An object of the present disclosure is to provide a ceiling-embedded air conditioner as described below. That is, the ceiling-embedded air conditioner prevents the retention of the air and realizes higher heat-exchange efficiency by suppressing occurrence of swirling airflows in the space between the turbo fan and the heat exchanger. 
     A ceiling-embedded air conditioner (the air conditioner) according to one embodiment of the present disclosure includes: a ceiling-embedded casing body that has an air suction path at the center of a lower surface and has an air blowoff path around the air suction path; a turbo fan that is disposed inside the casing body; a heat exchanger that is disposed inside the casing body on an outer peripheral side of the turbo fan; a bell-mouth that guides air sucked from the air suction path toward the inside of the turbo fan; and a rectifier that is provided on a back surface side of the bell-mouth at the air suction path side opposite to an air suction surface of the bell-mouth, the rectifier suppressing swirling airflows generated by part of air blown from the turbo fan swirling along the back surface of the bell-mouth in the same direction as a rotation direction of the turbo fan. 
     As a preferable embodiment, the rectifier is erected on the back surface of the bell-mouth. 
     As a more preferable embodiment, the rectifier has a first rectifying side vertically erected on the back surface of the bell-mouth as a base end and a second rectifying side horizontally extended from the leading end of the first rectifying side. The first rectifying side is formed in parallel to a ventilation surface of the heat exchanger. 
     Further, the rectifier is preferably formed integrally with the bell-mouth and is also provided as a reinforcement plate for reinforcing strength of the bell-mouth. 
     As another preferable embodiment, the air conditioner further includes a drain pan that is provided inside the casing body to receive dew condensation water generated by the heat exchanger. The rectifier is erected on the drain pan. 
     In addition, the heat exchanger preferably has first to fourth heat exchange portions. The rectifier is preferably disposed to be opposed to the first to fourth heat exchange portions with predetermined spacing therebetween and is positioned such that a distance between the ventilation surface of each of the heat exchange portions and an end surface of the rectifier opposed to the ventilation surface is the shortest. 
     According to the air conditioner, the rectifiers are provided on the back surface of the bell-mouth. By contacting swirling airflows on the rectifiers, the swirling airflows can be forcibly pushed out toward the heat exchanger on the outside of the bell-mouth. This suppresses the occurrence of swirling airflows in the space between the turbo fan and the heat exchanger and prevents the retention of the air. That is, pushing out the swirling airflows toward the heat exchanger increases the heat-exchange efficiency. 
     Next, an embodiment of the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to this. 
     As illustrated in  FIGS. 1 to 3 , a ceiling-embedded air conditioner  1  includes a cuboid-shaped casing body  2 . The cuboid-shaped casing body  2  is stored in the space formed between a ceiling slab and a ceiling panel. The casing body  2  is a box-shaped container having a top plate  21 , four side plates  22   a  to  22   d  (hereinafter, referred to as first to fourth side plates  22   a  to  22   d ), and a bottom surface  20 . The top plate  21  has a regular square shape with chamfered corners. The first to fourth side plates  22   a  to  22   d  are extended downward from the respective sides of the top plate  21 . The bottom surface  20  (lower surface in  FIG. 1 ) is opened. In this embodiment, the corners of the casing body  2  are chamfered according to the shape of the top plate  21 . 
     The bottom surface  20  of the casing body  2  is opened to the inside of the room. An air suction path  23  that is square in cross section is formed at the center of the bottom surface  20 . An air blowoff path  24  is formed on the bottom surface  20  of the casing body  2  to surround the four sides of the air suction path  23 . 
     A decorative panel  3  is screwed to the bottom surface  20  of the casing body  2 . The decorative panel  3  is made of a synthetic resin and has a flat regular square shape. A square air inlet  31  is provided at the center of the decorative panel  3 . The air inlet  31  communicates with the air suction path  23  of the casing body  2 . Rectangular air outlets  32  are disposed around the air inlet  31  at four places along the respective sides of the air inlet  31 . The air outlets  32  communicate with the air blowoff path  24  at the back surface side (ceiling surface side). 
     A suction grill  4  is provided to cover the air inlet  31 . The suction grill  4  is a synthetic resin molded component. The suction grill  4  is formed in a flat regular square shape to cover the bottom surface  20  of the casing body  2 . 
     In this embodiment, the air outlets  32  are respectively covered with electrically opening and closing wind direction plates  321 . During air-conditioning operation, the wind direction plates  321  are opened by a rotation member not illustrated provided on the back surface side of the decorative panel  3  to make the air outlets  32  appear. 
     The casing body  2  stores a turbo fan  5  as a blowing fan and a heat exchanger  6  therein. A bell-mouth  7  is disposed in the air suction path  23  ranging from the air inlet  31  to the turbo fan  5 . The bell-mouth  7  guides the air taken in from the air inlet  31  to the turbo fan  5 . 
     As illustrated in  FIGS. 2 and 3 , the turbo fan  5  includes a main plate  52 , a shroud  53 , and a plurality of blades  54 . The main plate  52  has a hub  521 . A rotation shaft  511  of a drive motor  51  is fixed to the center of the hub  521 . The shroud  53  is disposed to be opposed to the main plate  52  along the direction of axis of the rotation shaft  511 . The plurality of blades  54  is disposed between the main plate  52  and the shroud  53 . An opening  531  is provided at the center of the shroud  53  for inserting a part of the bell-mouth  7  into the turbo fan  5 . 
     The turbo fan  5  is disposed at almost the center of inside of the casing body  2 . The turbo fan  5  is hung and held by the drive motor (fan motor)  51  mounted on the top plate  21 . Accordingly, as the turbo fan  5  is driven to rotate, the bell-mouth  7  is under negative pressure at the air inlet  31  side (lower side in  FIG. 3 ). Therefore, the air taken in from the air inlet  31  is sucked into the turbo fan  5  through the bell-mouth  7 , and is blown toward the outer peripheral direction through the blades  54 . 
     As illustrated in  FIGS. 3 and 6 , the heat exchanger  6  is vertically extended from the top plate  21  to the opening in a bottom surface  20 . The heat exchanger  6  is formed in a square frame shape to surround the outer periphery of the turbo fan  5 . The heat exchanger  6  has a first heat exchange portion  6   a , a second heat exchange portion  6   b , a third heat exchange portion  6   c , and a fourth heat exchange portion  6   d . The first heat exchange portion  6   a  is disposed in parallel to the first side plate  22   a . The second heat exchange portion  6   b  is disposed in parallel to the second side plate  22   b . The third heat exchange portion  6   c  is disposed in parallel to the third side plate  22   c . The fourth heat exchange portion  6   d  is disposed in parallel to the fourth side plate  22   d.    
     In this embodiment, the heat exchanger  6  includes an elongated square plate-like body with four bent portions. The heat exchanger  6  has a heat-radiation fin group  61  including a large number of strip-shaped heat-radiation fins. The large number of heat-radiation fins is disposed at predetermined spacing therebetween. In the heat exchanger  6 , a large number of heat-transfer tubes  62  are inserted into the heat-radiation fin group  61  in parallel to one another. 
     As illustrated in  FIG. 6 , the heat exchanger  6  has four bent portions  6   e  to  6   h . Of these bent portions, the first bent portion  6   e  is formed between the first heat exchange portion  6   a  and the second heat exchange portion  6   b . The second bent portion  6   f  is formed between the second heat exchange portion  6   b  and the third heat exchange portion  6   c . The first bent portion  6   e  is bent such that the angle formed by the first heat exchange portion  6   a  and the second heat exchange portion  6   b  is a right angle. The second bent portion  6   f  is bent such that the angle formed by the second heat exchange portion  6   b  and the third heat exchange portion  6   c  is a right angle. 
     The third bent portion  6   g  and the fourth bent portion  6   h  are positioned between the third heat exchange portion  6   c  and the fourth heat exchange portion  6   d . The third bent portion  6   g  and the fourth bent portion  6   h  are bent such that, when the third bent portion  6   g  and the fourth bent portion  6   h  are combined with each other, the angle formed by the third heat exchange portion  6   c  and the fourth heat exchange portion  6   d  is a right angle to provide an installation space for a drain pump (not illustrated). The fourth bent portion  6   h  may not be provided between the third heat exchange portion  6   c  and the fourth heat exchange portion  6   d . In this case, the third bent portion  6   g , which is disposed between the third heat exchange portion  6   c  and the fourth heat exchange portion  6   d , may be bent such that the angle formed by the third heat exchange portion  6   c  and the fourth heat exchange portion  6   d  is a right angle. 
     The end portions of the heat-transfer tubes  62  are drawn from both end portions  63  and  64  of the heat exchanger  6 . A U-shaped tube (not illustrated) is coupled to the one end portion  63 . At the other end portion  64 , gas-side tubes are united into one collective tube and coupled to a gas-side pipe G, and liquid-side tubes are united into one collective tube and coupled to a liquid-side pipe L. 
     In this embodiment, the heat exchanger  6  is formed in a square shape in a plane view of  FIG. 6  by bending one heat exchanger. Instead of this, the heat exchanger  6  may be formed by coupling four small-sized heat exchangers at the end portions. 
     As described above, the heat exchanger  6  is bent at the first to fourth bent portions  6   e  to  6   h . Accordingly, the heat exchanger  6  is bent in a square shape in a plane view. In addition, the heat exchanger  6  has the end portions  63  and  64  disposed at a predetermined spacing therebetween. 
     In this embodiment, as illustrated in  FIG. 6 , the end portions  63  and  64  are disposed at an upper right corner A of the casing body  2 . The gas-side pipe G and the liquid-side pipe L are drawn outward from the corner A of the casing body  2 . 
     The heat exchanger  6  is connected to a reversible refrigeration cycle circuit not illustrated that allows cooling operation and heating operation. The heat exchanger  6  serves as an evaporator to cool the air during cooling operation. Meanwhile, the heat exchanger  6  serves as a condenser to heat the air during heating operation. 
     Drain pans  8  are provided at the lower end side of the heat exchanger  6  to receive dew condensation water generated by the heat exchanger  6 . The drain pans  8  are provided inside the casing body  2  and are provided with gutters  81 . The gutters  81  store the lower end side of the heat exchanger  6 . The dew condensation water dropped from the heat exchanger  6  is received at the gutters  81  and drawn up by a drain pump not illustrated. 
     The bell-mouth  7  is composed of a synthetic resin molded component. The bell-mouth  7  includes a base portion  71  and a suction guide portion  72  as illustrated in  FIGS. 4A, 4B, 5A, and 5B . The bell-mouth  7  is screwed into the drain pans  8 . The base portion  71  is disposed at a front surface (air suction surface)  7 A side (plane side in  FIG. 4A ), and is formed in a square shape corresponding to the shape of the air inlet  31 . The suction guide portion  72  is formed in a trumpet shape from the center of the base portion  71  toward the inside of the turbo fan  5 . 
     The base portion  71  is a concave formed in a square shape corresponding to the shape of the air inlet  31 . A storage concave portion  73 , in which the electrical equipment box  9  described later is to be disposed, is formed in a part of the base portion  71 . The storage concave portion  73  has a corner positioned above the corner A of the casing body  2  (refer to  FIG. 2 ). The storage concave portion  73  is extended from the corner as a center in parallel to the first heat exchange portion  6   a  and the fourth heat exchange portion  6   d . The electrical equipment box  9  is stored in the storage concave portion  73 . 
     The suction guide portion  72  is formed in a trumpet shape (funnel shape) to be gradually smaller in outer diameter with increasing proximity to the center of the rotation shaft  511  of the turbo fan  5 . The suction guide portion  72  has a round edge  721  at the upper end side. The edge  721  is inserted into the opening  531  of the turbo fan  5 . 
     The back surface  7 B of the bell-mouth  7  (plane side in  FIG. 4B ) is shaped according to the shapes of the base portion  71 , the suction guide portion  72 , and the storage concave portion  73 . The back surface  7 B is opposite to the front surface (air suction surface)  7 A of the bell-mouth  7  at the air suction path  23  side. Rectifiers  74  are provided on the back surface  7 B of the bell-mouth  7 . The rectifiers  74  suppress swirling airflows generated by part of the air blown from the turbo fan  5  swirling along the back surface  7 B of the bell-mouth  7  in the same direction as the rotation direction of the turbo fan  5 . 
     The rectifiers  74  are formed in a plate shape. Each of the rectifiers  74  has a first rectifying side  741  and a second rectifying side  742 . The first rectifying side  741  is vertically extended from the back surface of the bell-mouth  7  (base portion  71 ) in the vicinity of a boundary portion  711  between the base portion  71  and the suction guide portion  72 . That is, the rectifier  74  is erected on the back surface  7 B of the bell-mouth  7 . The second rectifying side  742  is horizontally extended from the upper end of the first rectifying side  741  to the edge  721  of the suction guide portion  72 . In this example, the rectifiers  74  are provided at four positions by 90 degrees. 
     The first rectifying side  741  of the rectifier  74  is a side vertical to the base portion  71  as described above. As illustrated in  FIG. 3 , the first rectifying side  741  is disposed in parallel to a ventilation surface  65  of the heat exchanger  6  opposed to the first rectifying side  741 . The rectifier  74  is positioned such that the distance between the first rectifying side  741  and the ventilation surface  65  of each of the heat exchange portions  6   a  to  6   d  is the shortest (the first rectifying side  741  and the ventilation surface  65  of each of the heat exchange portions  6   a  to  6   d  are closest to each other). In this embodiment, the rectifier  74  is positioned such that the distance between the circular-shaped boundary portion  711  and the outer periphery  712  of the square base portion  71  is the shortest. 
     Of the rectifiers  74 , a rectifier  74   a  disposed on the back surface side of the storage concave portion  73  is formed on the storage concave portion  73 . Accordingly, the base portion of the rectifier  74   a  (portion in contact with the storage concave portion  73 ) is shifted toward the round edge  721  according to the shape of the storage concave portion  73 . Therefore, the first rectifying side  741  of the rectifier  74   a  is shorter than the first rectifying sides  741  of the other rectifiers  74 . Meanwhile, the second rectifying sides  742  of the rectifiers  74  are flush with one another. 
     According to this, as illustrated in  FIG. 8 , the rectifiers  74  stem swirling airflows along the back surface of the bell-mouth  7  and push forcibly the air out to the outside of the bell-mouth  7 . Accordingly, it is possible to suppress swirling airflows generating in the space between the turbo fan  5  and the heat exchanger  6 , prevent the retention of the air, and push the swirling airflows out toward the heat exchanger side. This enhances the efficiency of heat exchange. 
     The rectifiers  74  are formed integrally with the bell-mouth  7  to serve also as reinforcement plates for reinforcing the strength of the bell-mouth  7 . That is, the rectifiers  74  improve the strength of the bell-mouth  7 . This suppresses thermal deformation of the bell-mouth  7  at the time of molding, and increases the dimensional accuracy of the bell-mouth  7 . Therefore, the gap between the bell-mouth  7  and  53  can be further narrowed. As a result, the recirculation of the air from the gap to the turbo fan  5  is decreased to further enhance the efficiency of heat exchange. 
     In this embodiment, the rectifiers  74  are formed integrally with the back surface of the bell-mouth  7 . Note that the rectifiers  74  may be merely disposed in the ceiling-embedded air conditioner  1  to block swirling airflows along the back surface of the bell-mouth  7 . Accordingly, the positions of the rectifiers  74  may not be limited to the bell-mouth  7 . 
     Specifically, as illustrated in  FIG. 7 , second rectifiers  82  are erected on the drain pans  8 . The second rectifiers  82  shut off swirling airflows in cooperation with the rectifiers  74  (hereinafter, referred to as first rectifiers  74 ). The second rectifiers  82  are plate bodies screwed to the upper ends of the gutters  81  at the turbo fan  5  side to be opposed to the respective first rectifiers  74 . The second rectifiers  82  are disposed in parallel to the first rectifiers  74 . 
     The second rectifiers  82  are aligned in height to the second rectifying sides  742  of the first rectifiers  74 . The second rectifiers  82  are disposed in abutment with the first rectifying sides  741  of the first rectifiers  74 . Accordingly, each of the first rectifiers  74  and each of the second rectifiers  82  serve as one large rectifier. Swirling airflows contacting the first rectifiers  74  move to the vicinity of the heat exchanger  6  from the first rectifiers  74  through the second rectifiers  82 . This further enhances the efficiency of heat exchange. 
     In the embodiment illustrated in  FIG. 7 , the corresponding first rectifiers  74  and second rectifiers  82  are combined to form one large rectifier. Alternatively, either the first rectifiers  74  or the second rectifiers  82  may be disposed in the ceiling-embedded air conditioner  1 . In this case, the disposed first rectifiers  74  or second rectifiers  82  are preferably formed in a large size. The respective second rectifiers  82  may be disposed to be opposed to the first to fourth heat exchange portions  6   a  to  6   d  at predetermined spacing, such that the distances between the ventilation surfaces  65  of the heat exchange portions  6   a  to  6   d  and the end surfaces of the rectifiers  82  opposed to the ventilation surfaces  65  are the shortest. 
     As illustrated in  FIGS. 2 and 6 , the electrical equipment box  9  includes a box body  91  and a lid portion  92 . The box body  91  has an opened upper surface and stores a substrate and/or electrical equipment (both not illustrated). The lid portion  92  closes the opened surface of the box body  91 . In this embodiment, the electrical equipment box  9  is formed by bending a metal plate, for example. 
     The box body  91  has a first storage portion  91   a  and a second storage portion  91   b . The box body  91  is formed in an L shape such that the first storage portion  91   a  and the second storage portion  91   b  are orthogonal to each other. A temperature-humidity sensor  93  is erected on the side wall of the first storage portion  91   a  opposed to the suction guide portion  72 . 
     The lid portion  92  is formed in an L shape adapted to the opening of the box body  91 . The lid portion  92  includes a first lid portion  92   a  covering the first storage portion  91   a  and a second lid portion  92   b  covering the second storage portion  91   b . The lid portion  92  is horizontally formed along the open surface of the box body  91 . A tapered surface  94  is formed at a corner of the lid portion  92  opposed to the suction guide portion  72 . The height of the tapered surface  94  is gradually lower from the upstream to downstream sides of the blowing direction. 
     Accordingly, the air flowing along the surface of the electrical equipment box  9  can be smoothly guided to the bell-mouth  7  through the tapered surface  94 . This reduces ventilation resistance and suppresses decrease in heat exchange efficiency. 
     As described above, according to the embodiment of the present disclosure, the rectifiers are provided on the back surface of the bell-mouth. By contacting swirling airflows on the rectifiers, it is possible to suppress swirling airflows generated in the space between the turbo fan  5  and the heat exchanger  6  and prevent the retention of the air. That is, the efficiency of heat exchange can be enhanced by pushing swirling airflows out toward the heat exchanger. 
     The expressions herein indicating shapes or states such as regular square, rectangular, square, circular, vertical, parallel, right angle, 90 degrees, the same, orthogonal, and horizontal, signify not only strict shapes or states but also approximate shapes or states shifted from the strict shapes or states, without deviating from the scope in which the operations and effects of these shapes or states can be achieved. 
     The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto.