Abstract:
An air conditioner includes a scroll body comprising an inlet through which air is introduced, an outlet through which the air is discharged, and an air passage between the inlet and the outlet, a sirocco fan rotatably disposed in the scroll body, the sirocco fan configured to allow the air to be sucked through the inlet and to be discharged through the outlet when the sirocco fan rotates, and a bell mouth formed around the inlet of the scroll body, wherein the scroll body and the sirocco fan satisfy a following formula: 0.76≦H/D≦0.8,
       where H (mm) is a height of the scroll body, and D (mm) is an outer diameter of the sirocco fan.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority benefit from Korean Patent Application No. 10-2015-0023568 filed Feb. 16, 2015 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    The present disclosure relates to an air conditioner. More particularly, the present disclosure relates to a scroll for an air conditioner provided with a sirocco fan therein and an air conditioner having the same. 
         [0004]    2. Description of the Related Art 
         [0005]    Generally, sirocco fans that may blow wind of a band shape with a wide width toward the indoor are widely used in a ceiling type air conditioner disposed in a ceiling of a room. 
         [0006]    The sirocco fan has a plurality of blades, and is disposed inside a scroll. When the sirocco fan rotates, the sirocco fan generates a pressure change to form a flow field. 
         [0007]    The scroll has a function that collects air discharged from the sirocco fan and pushes the air toward of the outside of the scroll. The scroll changes dynamic pressure of the air discharged from the sirocco fan into static pressure, thereby increasing the static pressure at the outlet. Accordingly, the shape of the scroll gives a lot of effects to the performance of the sirocco fan. 
         [0008]    As illustrated in  FIG. 1 , a conventional scroll  100  is provided with a bell mouth  110  to reduce flow resistance of external air in an inlet  101  through which the external air is introduced. However, the conventional bell mouth  110  is formed in a round shape having a predetermined curvature as illustrated in  FIG. 1 . 
         [0009]    In the conventional round shaped bell mouth  110 , since layered suction flow is formed in the vicinity of the bell mouth  110  as illustrated in  FIG. 2 , there is great difference in pressure distribution due to the shape of the bell mouth  110 . Accordingly, the suction flow is unstable due to the difference in the pressure distribution in the vicinity of the bell mouth  110  so that the blowing efficiency of the sirocco fan is degraded. In reference, since a dark portion represents a low pressure area and a light portion represents a high pressure area in  FIG. 2 , it can be seen that the pressure of an area closer to the bell mouth  110  is lower. 
       SUMMARY 
       [0010]    The present disclosure has been developed in order to overcome the above drawbacks and other problems associated with the conventional arrangement. An aspect of the present disclosure relates to a scroll for an air conditioner having a shape capable of maximizing a blowing efficiency of a sirocco fan in accordance with a height of the air conditioner. 
         [0011]    Another aspect of the present disclosure relates to blades of a sirocco fan having a shape capable of maximizing a blowing efficiency of the sirocco fan. 
         [0012]    According to an aspect of the present disclosure, an air conditioner may include a scroll body comprising an inlet through which air is introduced, an outlet through which the air is discharged, and an air passage between the inlet and the outlet; a sirocco fan rotatably disposed in the scroll body, the sirocco fan configured to allow the air to be sucked through the inlet and to be discharged through the outlet when the sirocco fan rotates; and a bell mouth formed around the inlet of the scroll body, wherein the scroll body and the sirocco fan satisfy a following formula: 
         [0000]      0.76≦ H/D≦ 0.8
 
         [0013]    where H (mm) is a height of the scroll body, and D (mm) is an outer diameter of the sirocco fan. 
         [0014]    The bell mouth may be formed in a two-step structure extending from a side wall of the scroll body to an inside of the scroll body so that inner diameters of the bell mouth are smaller toward the inside of the scroll body. 
         [0015]    The bell mouth may include a first inclined portion which is bent inwardly extending from the side wall of the scroll body; a flat portion which is bent substantially parallel to the side wall of the scroll body and extends from the first inclined portion; and a second inclined portion which is bent inwardly extending from the flat portion. 
         [0016]    The scroll for an air conditioner may include a cutoff formed in an upper surface of the outlet of the scroll body, wherein the cutoff is formed in a position to satisfy a following formula: 
         [0000]      0.13≦ Sv/Sh≦ 0.15
 
         [0017]    where Sv is a vertical distance from a center of the inlet of the scroll body to an apex of the cutoff, and Sh is a horizontal distance from the center of the inlet of the scroll body to the apex of the cutoff. 
         [0018]    The scroll body may include a circumferential surface formed of a plurality of curved surfaces whose radii from the center of the inlet of the scroll body are different, wherein the plurality of curved surfaces may include a first circumferential surface connected to the outlet and a second circumferential surface connected to the first circumferential surface, and wherein the circumferential surface of the scroll body may be formed to satisfy a following formula: 
         [0000]      0.7≦ V 2/ V 1≦0.75
 
         [0019]    where V1 is a radius from the center of the inlet of the scroll body to the first circumferential surface of the scroll body, and V2 is a radius from the center of the inlet of the scroll body to the second circumferential surface of the scroll body. 
         [0020]    The sirocco fan may include a pair of rings to face each other; and a plurality of blades disposed between the pair of rings, and wherein an end of each of the plurality of blades in contact with the pair of rings is formed to have a step. 
         [0021]    The step of the blade may have a height of about 5% of a length of the blade. 
         [0022]    The sirocco fan may include a pair of rings to face each other; and a plurality of blades disposed between the pair of rings, and wherein each of the plurality of blades satisfies following formulas: 
         [0000]      0.17≦ B/L≦ 0.2,
 
         [0000]      95°≦β1≦105°,
 
         [0000]      35°≦β2≦45°
 
         [0023]    wherein B is a height of the blade, L is a length of a chord of the blade, β1 is an inlet angle of an inlet end of the blade closer to a rotational center of the sirocco fan, and β2 is an outlet angle of an outlet end of the blade farther from the rotational center of the sirocco fan. 
         [0024]    Each of the plurality of blade may satisfy a following formula: 
         [0000]      4.5≦ d/L≦ 5.5
 
         [0025]    where d is an inner diameter of the sirocco fan. 
         [0026]    According to another aspect of the present disclosure, a scroll for an air conditioner may include a scroll body comprising an inlet through which air is introduced, an outlet through which the air is discharged, and an air passage between the inlet and the outlet; a sirocco fan rotatably disposed in the scroll body, the sirocco fan configured to allow the air to be introduced through the inlet and to be discharged through the outlet when the sirocco fan rotates; and a bell mouth formed around the inlet of the scroll body, wherein the scroll body and the sirocco fan are formed to satisfy a following formula: 
         [0000]      0.76≦ H/D≦ 0.8
 
         [0027]    where H (mm) is a height of the scroll body, and D (mm) is an outer diameter of the sirocco fan, and wherein the bell mouth is formed in a two-step structure extending from a side wall of the scroll body to an inside of the scroll body, the bell mouth comprises two inclined portions and one flat portion, and inner diameters of the two inclined portions are formed to be smaller toward the inside of the scroll body. 
         [0028]    According to another aspect of the present disclosure, an air conditioner may include a heat exchanger; and a scroll for the air conditioner disposed to blow the air toward the heat exchanger, the scroll having any one of the above described features. 
         [0029]    Other objects, advantages and salient features of the present disclosure will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    These and/or other aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings of which: 
           [0031]      FIG. 1  is a perspective view illustrating a conventional scroll; 
           [0032]      FIG. 2  is a view illustrating a result obtained by analyzing a suction flow of air introduced into a bell mouth of the conventional scroll of  FIG. 1 ; 
           [0033]      FIG. 3  is a perspective view illustrating an air conditioner according to an embodiment of the present disclosure; 
           [0034]      FIG. 4  is a cross-sectional perspective view illustrating the air conditioner of  FIG. 3 ; 
           [0035]      FIG. 5  is a perspective view illustrating a scroll that may be used in an air conditioner according to an embodiment of the present disclosure; 
           [0036]      FIG. 6  is an exploded perspective view illustrating the scroll of  FIG. 5 ; 
           [0037]      FIG. 7  is a perspective view illustrating a scroll body of a scroll for an air conditioner according to an embodiment of the present disclosure; 
           [0038]      FIG. 8  is a partial cross-sectional view illustrating a bell mouth of the scroll body taken along a line  8 - 8  in  FIG. 7 ; 
           [0039]      FIG. 9  is a cross-sectional view illustrating a state in which a sirocco fan is assembled in a scroll body of a scroll for an air conditioner according to an embodiment of the present disclosure; 
           [0040]      FIG. 10  is a cross-sectional view illustrating a scroll body of a scroll for an air conditioner according to an embodiment of the present disclosure; 
           [0041]      FIG. 11  is a view illustrating a result obtained by analyzing a suction flow of air introduced into the bell mouth of  FIG. 8 ; 
           [0042]      FIG. 12  is a graph illustrating a performance test result according to ratios of a diameter of a sirocco fan to a height of a scroll in a scroll for an air conditioner according to an embodiment of the present disclosure; 
           [0043]      FIG. 13  is a perspective view illustrating a sirocco fan according to an embodiment of the present disclosure; 
           [0044]      FIG. 14  is a partial perspective view illustrating an end portion of a sirocco fan according to an embodiment of the present disclosure; 
           [0045]      FIG. 15  is a plan view illustrating a blade of a sirocco fan according to an embodiment of the present disclosure; 
           [0046]      FIG. 16  is a graph comparing flow rate distribution at a rear end of a conventional sirocco fan and of a sirocco fan according to an embodiment of the present disclosure; 
           [0047]      FIG. 17  is a graph comparing sound pressure levels according to inlet and outlet angles of a blade of a conventional sirocco fan and of a blade of a sirocco fan according to an embodiment of the present disclosure; and 
           [0048]      FIG. 18  is a graph comparing power consumption according to inlet and outlet angles of a blade of a conventional sirocco fan and of a blade of a sirocco fan according to an embodiment of the present disclosure. 
       
    
    
       [0049]    Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures. 
       DETAILED DESCRIPTION 
       [0050]    Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
         [0051]    The matters defined herein, such as a detailed construction and elements thereof, are provided to assist in a comprehensive understanding of this description. Thus, it is apparent that exemplary embodiments may be carried out without those defined matters. Also, well-known functions or constructions are omitted to provide a clear and concise description of exemplary embodiments. Further, dimensions of various elements in the accompanying drawings may be arbitrarily increased or decreased for assisting in a comprehensive understanding. 
         [0052]    The terms used in the present application are only used to describe the exemplary embodiments, but are not intended to limit the scope of the disclosure. The singular expression also includes the plural meaning as long as it does not differently mean in the context. In the present application, the terms “include” and “consist of” designate the presence of features, numbers, steps, operations, components, elements, or a combination thereof that are written in the specification, but do not exclude the presence or possibility of addition of one or more other features, numbers, steps, operations, components, elements, or a combination thereof. 
         [0053]      FIG. 3  is a perspective view illustrating an air conditioner according to an embodiment of the present disclosure.  FIG. 4  is a cross-sectional perspective view illustrating the air conditioner of  FIG. 3 . 
         [0054]    Referring to  FIGS. 3 and 4 , an air conditioner  1  according to an embodiment of the present disclosure may include a cabinet  10 , a heat exchanger  20 , and a scroll  30 . 
         [0055]    In  FIGS. 3 and 4 , the air conditioner  1  illustrates only an indoor unit. Although not illustrated, the air conditioner  1  may include an outdoor unit. The outdoor unit may include a compressor and a condenser, and is the same as or similar to a conventional outdoor unit. Therefore, a detailed description of the outdoor unit will be omitted. The air conditioner  1  according to an embodiment of the present disclosure may be disposed in a ceiling of a room or on a floor adjacent to one side wall of the room. 
         [0056]    The cabinet  10  forms an outer appearance of the indoor unit of the air conditioner  1 , and is provided with a discharge port  11  formed to discharge air in one side surface of the cabinet  10 . The cabinet  10  is formed in a substantially rectangular parallelepiped shape, and fixes and supports the heat exchanger  20  and the scroll  30 . The cabinet  10  is provided with an air inlet grill  13  in a bottom surface of the cabinet  10 . 
         [0057]    The heat exchanger  20  is disposed adjacent to the discharge port  11  inside the cabinet  10 . Refrigerant that has low temperature and low pressure and is in a liquid state flows inside the heat exchanger  20 . Accordingly, when hot air passes through the heat exchanger  20 , the hot air is deprived of heat by the refrigerant so as to become cold air. In order to make the thickness of the indoor unit  1  thin, the whole shape of the heat exchanger  20  may be formed in a thin plate shape, and may be disposed obliquely with respect to the discharge port  11 . 
         [0058]    The scroll  30  sucks the external air and discharges the sucked air to the heat exchanger  20 . The scroll  30  is disposed such that an outlet of the scroll  30  faces the discharge port  11 . The air introduced through the air inlet grill  13  of the cabinet  10  enters the scroll  30 . At least one scroll  30  may be used depending on the capacity of the air conditioner  1 . In general, three or four scrolls  30  may be used. When a plurality of scrolls  30  are to be used, the plurality of scrolls  30  are disposed in a straight line parallel to the discharge port  11 . 
         [0059]    Hereinafter, the scroll  30  for an air conditioner  1  according to an embodiment of the present disclosure will be described with reference to  FIGS. 5 to 10 . 
         [0060]      FIG. 5  is a perspective view illustrating a scroll that may be used in an air conditioner according to an embodiment of the present disclosure, and  FIG. 6  is an exploded perspective view illustrating the scroll of  FIG. 5 .  FIG. 7  is a perspective view illustrating a scroll body of a scroll for an air conditioner according to an embodiment of the present disclosure.  FIG. 8  is a partial cross-sectional view illustrating a bell mouth of the scroll body taken along a line  8 - 8  in  FIG. 7 .  FIG. 9  is a cross-sectional view illustrating a state in which a sirocco fan is assembled in a scroll body of a scroll for an air conditioner according to an embodiment of the present disclosure.  FIG. 10  is a cross-sectional view illustrating a scroll body of a scroll for an air conditioner according to an embodiment of the present disclosure. 
         [0061]    The scroll  30  for the air conditioner according to an embodiment of the present disclosure includes a scroll body  31  and a sirocco fan  40 . 
         [0062]    The scroll body  31  accommodates the sirocco fan  40  and forms an air passage  35  therein. The scroll body  31  includes an inlet  32  that is formed concentrically with a rotational center O 1  of the sirocco fan  40  and through which the air is introduced, an outlet  34  that discharges the air introduced through the inlet  32  toward the heat exchanger  20 , and the air passage  35  that surrounds the sirocco fan  40 , is formed in a curved shape, and allows the inlet  32  to be in communication with the outlet  34 . The two inlets  32  are formed concentrically in the opposite side walls  33  of the scroll body  31 . 
         [0063]    A bell mouth  50  may be formed in the inlet  32  of the scroll body  31  in order to stabilize the air being introduced through the inlet  32 . The opposite side walls  33  of the scroll body  31  are connected to a circumferential surface  36  forming the air passage  35 . The circumferential surface  36  may be formed in a shape connecting a plurality of curved surfaces rather than a circular cross-section. The plurality of curved surfaces may be formed such that a radius of each of the plurality of curved surfaces is increased toward the outlet  34 . 
         [0064]    The sirocco fan  40  is rotatably disposed inside the scroll body  31 , and when the sirocco fan  40  rotates, the air in the atmospheric pressure is sucked into the inlet  32  of the scroll body  31 , becomes the air flow of the high-pressure, and then is discharged through the outlet  34 . In detail, the sirocco fan  40  is formed in a cylindrical shape, and has a plurality of thin and long blades  60  arranged on the circumference. The sirocco fan  40  is formed to be rotated by a motor (not illustrated) disposed at one side of the sirocco fan  40 . When the sirocco fan  40  is rotated, the external air is introduced into the inside of the sirocco fan  40  through the inlet  32  of the scroll body  31 , and then is discharged toward the outlet  34  of the scroll body  31  through space between the plurality of blades  60 . 
         [0065]    In order to improve the blowing air performance of the sirocco fan  40 , for example, the blowing air volume, a diameter D (see  FIG. 9 ) of the sirocco fan  40  may be increased. The larger the diameter of the sirocco fan  40  is, the larger the size of the scroll  30  accommodating the sirocco fan  40  is. Therefore, the height h (see  FIG. 4 ) of the cabinet  10  is increased. However, because there is a limit to the height h of the air conditioner  1  disposed in the ceiling, the height h of the cabinet  10  may not be increased as desired. Accordingly, in a state in which the height h of the cabinet  10  is fixed, it is necessary to determine the shape of the scroll  30  to maximize the blowing air performance of the sirocco fan  40  depending on the diameter D of the sirocco fan  40 . 
         [0066]    When the height of the scroll body  31  and the outer diameter of the sirocco fan  40  satisfy a following condition, the blowing air performance of the sirocco fan  40  is improved. 
         [0000]      0.76≦ H/D≦ 0.8
 
         [0067]    Here, H (mm) is the height of the scroll body  31 , and D (mm) is the outer diameter of the sirocco fan  40 . The height H of the scroll body  31  refers to the height of the highest point in the scroll body  31  when the scroll  30  is disposed in the cabinet  10  as illustrated in  FIG. 4 . In detail, as illustrated in  FIG. 9 , the height H of the scroll body  31  is the height from a bottom surface  36 - 5  of the scroll body  31  extending from the outlet  34  to a top end of the scroll body  31  measured on a vertical line passing through the rotational center O 1  of the sirocco fan  40 . Accordingly, the height H of the scroll body  31  is the same as the height of the scroll  30 . 
         [0068]    A test result of the blowing air volume of the sirocco fan  40  in accordance with the ratio of the outer diameter D of the sirocco fan  40  to the height H of the scroll body  31  is shown in  FIG. 12 . 
         [0069]      FIG. 12  is a graph illustrating a performance test result according to the ratio of the outer diameter D of the sirocco fan  40  to the height H of the scroll body  31  in the scroll  30  for an air conditioner according to an embodiment of the present disclosure. 
         [0070]    Referring to  FIG. 12 , it may be seen that the blowing air volume is maximum where the ratio of the outer diameter D of the sirocco fan  40  to the height H of the scroll body  31  is near 0.78. 
         [0071]    Also, the blowing air performance of the sirocco fan  40  may be improved by determining a position relationship between a cutoff  39 , which is formed on an upper surface of the outlet  34  of the scroll body  31 , and the center O 2  of the inlet  32  as follows. The cutoff  39  is formed in a curved surface shape projecting from the upper surface of the outlet  34  toward a lower surface of the outlet  34 . 
         [0000]      0.13≦ Sv/Sh≦ 0.15
 
         [0072]    Here, Sv represents a vertical distance from an imaginary horizontal extension line of the center O 2  of the inlet  32  of the scroll body  31  to the apex P of the cutoff  39 . Sh represents a horizontal distance from an imaginary vertical extension line of the center O 2  of the inlet  32  of the scroll body  31  to the apex P of the cutoff  39 . The imaginary horizontal extension line and the imaginary vertical extension line are perpendicular to each other. Here, the apex P of the cutoff  39  refers to the highest point on the cutoff  39  of the curved surface projecting from the upper surface of the outlet  34 . 
         [0073]    At this time, since the center O 2  of the inlet  32  of the scroll body  31  is approximately the same location as the rotational center O 1  of the sirocco fan  40 , the apex P of the cutoff  39  of the scroll body  31  may have the above-described position relationship with respect to the rotational center O 1  of the sirocco fan  40 . 
         [0074]    Also, if the circumferential surface  36  of the scroll body  31  forming the air passage  35  is formed to satisfy a condition as follows, the blowing air performance of the sirocco fan  40  may be improved. 
         [0000]      0.7≦ V 2/ V 1≦0.75
 
         [0075]    Here, V1 represents a radius from the center O 2  of the inlet  32  of the scroll body  31  to a first circumferential surface  36 - 1  of the scroll body  31 , and V2 represents a radius from the center O 2  of the inlet  32  of the scroll body  31  to a second circumferential surface  6 - 2  of the scroll body  31 . 
         [0076]    At this time, one end of the first circumferential surface  36 - 1  is connected to a bottom surface  36 - 5  of the outlet  34 , and the other end of the first circumferential surface  36 - 1  is connected to the second circumferential surface  36 - 2 . The radius V1 of the first circumferential surface  36 - 1  is formed to be larger than the radius V2 of the second circumferential surface  36 - 2 . The first circumferential surface  36 - 1  may be formed of a length corresponding to approximately 70 degrees O 1  of a subtended angle at the center O 2  of the inlet  32  of the scroll body  31 . 
         [0077]    One end of the second circumferential surface  36 - 2  is connected to the first circumferential surface  36 - 1 , and the other end of the second circumferential surface  36 - 2  is connected to a third circumferential surface  36 - 3 . The second circumferential surface  36 - 2  may be formed of a length corresponding to approximately 20 degrees θ 2  of a subtended angle at the center O 2  of the inlet  32  of the scroll body  31 . 
         [0078]    The third circumferential surface  36 - 3  is formed to have a radius smaller than the second circumferential surface  36 - 2 . One end of the third circumferential surface  36 - 3  is connected to the second circumferential surface  36 - 2 , and the other end of the third circumferential surface  36 - 3  is connected to a fourth circumferential surface  36 - 4 . 
         [0079]    One end of the fourth circumferential surface  36 - 4  is connected to the third circumferential surface  36 - 3 , and the other end of the fourth circumferential surface  36 - 4  is connected to the cutoff  39 . The fourth circumferential surface  36 - 4  is formed to have a radius smaller than the third circumferential surface  36 - 3 . 
         [0080]    Accordingly, the plurality of curved surfaces configuring the circumferential surface  36  of the scroll body  31 , for example, the first circumferential surface  36 - 1 , the second circumferential surface  36 - 2 , the third circumferential surface  36 - 3 , and the fourth circumferential surface  36 - 4  are formed to have a radius getting bigger from the fourth circumferential surface  36 - 4  toward the first circumferential surface  36 - 1 . 
         [0081]    In the present embodiment, the circumferential surface  36  of the scroll body  31  is formed of four curved surfaces  36 - 1 ,  36 - 2 ,  36 - 3 , and  36 - 4  having different radii. However, the number of the curved surfaces forming the circumferential surface  36  is not limited thereto. The number of the curved surfaces forming the circumferential surface  36  may be five or more. 
         [0082]    Also, the blowing air performance of the sirocco fan  40  may be improved by stabilizing the flow of the air entering the sirocco fan  40  through the inlet  32  of the scroll body  31 . For this, the bell mouth formed in the inlet of the scroll body may be formed in a multi-step structure. For example, the bell mouth  50  formed in the inlet  32  of the scroll body  31  may be formed in a two-step structure as illustrated in  FIGS. 7 and 8 . 
         [0083]    In detail, the bell mouth  50  is formed in a shape extending inwardly from the side wall  33  of the scroll body  31 , and is formed in the two-step structure. The two-step structure of the bell mouth  50  is formed so that the inner diameters of the bell mouth  50  are getting smaller toward the inside of the scroll body  31 . 
         [0084]    For example, the bell mouth  50  includes a first inclined portion  51  which is bent inwardly extending from the side wall  33  of the scroll body  31 , a flat portion  52  which is bent substantially parallel to the side wall  33  of the scroll body  31  and extends from the first inclined portion  51 , and a second inclined portion  53  which is bent inwardly extending from the flat portion  52 . 
         [0085]    The inner diameter d 1  of the first inclined portion  51  is formed to be larger than the inner diameter d 2  of the second inclined portion  53 . Also, the flat portion  52  is formed to be inwardly lower than the side wall  33  of the scroll body  31 . The first inclined portion  51 , the flat portion  52 , and the second inclined portion  53  configuring the bell mouth  50  may be formed to be connected to one another by a curved surface. 
         [0086]    If the bell mouth  50  is formed in the two-step structure, the air suction area of the inlet  32  may be widened in comparison with the inlet having the conventional bell mouth of a round shape. Accordingly, because the air introduced from the outside to the inlet  32  of the scroll body  31  moves along the bell mouth  50  bent in the two-step structure, a constant pressure distribution may be achieved. 
         [0087]      FIG. 11  is a view illustrating a result obtained by analyzing a suction flow of air introduced into the bell mouth  50  having the above-described structure. 
         [0088]    Referring to  FIG. 11 , it may be seen that the pressure distribution in the bell mouth  50  of the scroll body  31  according to an embodiment of the present disclosure is uniform unlike the conventional bell mouth as illustrated in  FIG. 2 . Accordingly, if the bell mouth  50  is formed in the two-step structure as the present disclosure, the pressure distribution of the air entering the scroll body  31  is uniform so that the suction flow of the air is stabilized. As a result, the blowing efficiency of the sirocco fan  40  also may be improved. In  FIG. 11 , a reference number  31   a  represents a space of the inside of the scroll body  31 . 
         [0089]    Further, in order to improve the blowing air performance of the sirocco fan  40 , a shape of each of the plurality of blades  60  constituting the sirocco fan  40  may be changed. The shape change of the blades of the sirocco fan  40  will be described in detail with reference to  FIGS. 13 to 15 . 
         [0090]      FIG. 13  is a perspective view illustrating a sirocco fan according to an embodiment of the present disclosure.  FIG. 14  is a partial perspective view illustrating an inflow end portion of a sirocco fan according to an embodiment of the present disclosure.  FIG. 15  is a plan view illustrating a blade of a sirocco fan according to an embodiment of the present disclosure. 
         [0091]    The present disclosure may be applied to a double suction sirocco fan  40  through the opposite side walls of which the air is introduced as illustrated in  FIG. 13 . 
         [0092]    Referring to  FIG. 13 , the double suction sirocco fan  40  is provided with a hub  43  in the middle thereof, and is provided with a pair of rings  41  in the opposite ends thereof. A plurality of blades  60  are arranged at a predetermined interval between the hub  43  and the pair of rings  41 . Accordingly, the air being introduced into the inlet  32  of the scroll body  31  enters the inside of the sirocco fan  40 , and then is discharged through spaces between the plurality of blades  60 . The center of the hub  43  is connected to a shaft of a motor (not illustrated) so that, when the motor rotates, the sirocco fan  40  is rotated. 
         [0093]    In the conventional sirocco fan, an end portion of each of the plurality of blades connected to the ring is formed to have the same height. In other words, the blade is formed to have the same length with respect to the entire width of the blade. However, if the end portion of the blade is formed to have the same height as described above, an eddy current is generated near the ring adjacent to the bell mouth, thereby increasing noise of the sirocco fan and degrading the blowing air performance of the sirocco fan. 
         [0094]    In order to solve this problem, the blades for the sirocco fan may have different shapes. For example, an end portion of blades may have different heights or shapes. In the sirocco fan  40  according to an embodiment of the present disclosure, the end portion  61  of the blade  60  is formed in two steps. In detail, as illustrated in  FIG. 14 , the end portion  61  of the blade  60  is formed in a step shape so that a height h 1  of a first end portion  61 - 1  close to the ring  41  is different from a height h 2  of a second end portion  61 - 2  adjacent to the rotational center O 1  of the sirocco fan  40 . At this time, the height h 1  of the first end portion  61 - 1  is formed to be higher than the height h 2  of the second end portion  61 - 2 , and the first end portion  61 - 1  is connected to the second end portion  61 - 2  by a curved surface. Here, the height h 1  of the first end portion  61 - 1  refers to the length of the blade  60  from the hub  43  to the first end portion  61 - 1 , and the height h 2  of the second end portion  61 - 2  refers to the length of the blade  60  from the hub  43  to the second end portion  61 - 2 . At this time, the height difference (h 1 −h 2 ) between the first end portion  61 - 1  and the second end portion  61 - 2 , that is, the height of the step may be approximately 5% of the length of the blade  60 . 
         [0095]    If the end portion  61  of the blade  60  is formed in the two-step structure as described above, the flow field of air is generated in the vicinity of the ring  41  of the sirocco fan  40 , thereby improving the efficiency of the sirocco fan  40 . 
         [0096]    A graph comparing the blowing air performance of the sirocco fan  40  having the blades  60  according to an embodiment of the present disclosure to that of a sirocco fan having the conventional blades is shown in  FIG. 16 . 
         [0097]      FIG. 16  is a graph comparing flow velocity distribution at a rear end of a conventional sirocco fan and of a sirocco fan according to an embodiment of the present disclosure. 
         [0098]    In  FIG. 16 , the position represents locations in which flow rates are measured in the entire length FL of the sirocco fan  40  (see  FIG. 13 ). The graph of  FIG. 16  shows the flow rates measured in 18 locations of the entire length FL of the sirocco fan  40  used for the measurement. 
         [0099]    Referring to  FIG. 16 , in the case of the conventional sirocco fan, the flow rate is fast in the vicinity of the hub in the middle of the sirocco fan, and variation in the flow rate is very large along the length of the sirocco fan. However, the sirocco fan  40  according to an embodiment of the present disclosure has a more uniform flow rate over the entire length than the conventional sirocco fan. Accordingly, it may be seen that the flow rate distribution of the sirocco fan  40  provided with blades  60  having the end portion  61  of the two-step structure according to an embodiment of the present disclosure is improved in comparison with the conventional sirocco fan provided with blades having the end portion of the same height. If it is calculated in figures, improved results of about 12.6% may be obtained. 
         [0100]    Further, in order to reduce noise and power consumption of the sirocco fan  40 , the shape of the blade  60  may be improved. 
         [0101]    Referring to  FIG. 15 , the blade  60  is formed in a streamline shape curved at a predetermined curvature. The air flowing into the scroll body  31  is discharged to the outside along the blade  60  from the inside of the sirocco fan  40 . Accordingly, as illustrated in  FIG. 15 , the air moves along the blade  60  in a direction of arrow A. Accordingly, an inlet end P 1  of the blade  60  is closer to the rotational center O 1  of the sirocco fan  40 , and an outlet end P 2  of the blade  60  is farther from the rotational center O 1  of the sirocco fan  40  and is connected to the ring  40 . 
         [0102]    The shape of the blade  60  may vary depending on an inlet angle, an outlet angle, and a height of the blade  60 . Here, the inlet angle of the blade  60  refers to an angle between a circle  45  connecting the inlet ends P 1  of the plurality of blades  60  and a center line BL of the blade  60 . The outlet angle of the blade  60  refers to an angle between the ring  41  connecting the outlet ends P 2  of the plurality of blades  60  and the center line BL of the blade  60 . Also, when a straight line connecting the inlet end P 1  and the outlet end P 2  of the blade  60  is referred to as a chord L of the blade  60 , the height B of the curved blade  60  may be measured based on the chord L of the blade  60 . Accordingly, the height B of the blade  60  is defined as the height of a point of the center line BL of the blade  60  that is highest from the chord L of the blade  60 . 
         [0103]    If the shape of the blade  60  is formed as a follow condition, the noise of the sirocco fan  40  may be reduced, and the power consumption may be reduced so that the efficiency of the sirocco fan  40  is increased. 
         [0000]      0.17≦ B/L≦ 0.2
 
         [0000]      95°≦β1≦105°
 
         [0000]      35°≦β2≦45°
 
         [0104]    Here, B represents a height of the blade  60 , L represents a length of the chord of the blade  60 ,  61  represents an inlet angle of the blade  60 , and  62  represents an outlet angle of the blade  60 . 
         [0105]    Also, the arrangement of the plurality of blades  60  may be changed by adjusting the ratio of the chord L of the blade  60  to the inner diameter d of the sirocco fan  40 . Accordingly, if the ratio of the chord L of the blade  60  to the inner diameter d of the sirocco fan  40  is determined in the following range, it is possible to reduce noise and power consumption of the sirocco fan  40 . 
         [0000]      4.5≦ d/L≦ 5.5
 
         [0106]    Here, d represents the inner diameter of the sirocco fan  40 , and L presents the length of the chord of the blade  60 . The inner diameter of the sirocco fan  40  refers to the diameter of the circle  45  connecting the inlet ends P 1  of the plurality of blades  60 . 
         [0107]    Graphs comparing noise and power consumption of the sirocco fan  40  having the blades  60  according to an embodiment of the present disclosure to those of a sirocco fan having the conventional blades are shown in  FIGS. 17 and 18 . 
         [0108]      FIG. 17  is a graph comparing sound pressure levels according to inlet and outlet angles of a blade of a conventional sirocco fan and of a blade  60  of a sirocco fan  40  according to an embodiment of the present disclosure, and  FIG. 18  is a graph comparing power consumption according to inlet and outlet angles of a blade of a conventional sirocco fan and of a blade  60  of a sirocco fan  40  according to an embodiment of the present disclosure. 
         [0109]    The graphs of  FIGS. 17 and 18  show the result measured in a state in which the inlet angle and the outlet angle of the blade  60  of the sirocco fan  40  are defined as the following table. At this time, the other dimensions of the blade  60  are maintained in the same values. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Blade according to a 
               
               
                   
                 Conventional blade 
                 present disclosure 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Inlet angle β1 
                 93° 
                 98° 
               
               
                   
                 Outlet angle β2 
                 21° 
                 37° 
               
               
                   
                   
               
             
          
         
       
     
         [0110]    Referring to  FIG. 17 , it may be seen that the sound pressure level SPL of the conventional sirocco fan is higher than that of the sirocco fan  40  according to an embodiment of the present disclosure. It may be seen from  FIG. 17  that the sound pressure level SPL of the sirocco fan  40  according to an embodiment of the present disclosure is decreased about 3.5 dB than that of the conventional sirocco fan. 
         [0111]    Also, referring to  FIG. 18 , it may be seen that the power consumption P of the sirocco fan  40  according to an embodiment of the present disclosure is smaller than that of the conventional sirocco fan. It may be seen from  FIG. 18  that the power consumption P of the sirocco fan  40  according to an embodiment of the present disclosure is decreased about 10W than that of the conventional sirocco fan. 
         [0112]    As described above, with the sirocco fan  40  according to an embodiment of the present disclosure, the blowing air performance may be improved, and noise and power consumption may be reduced. 
         [0113]    While embodiments of the present disclosure have been described, additional variations and modifications of the embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims shall be construed to include both above embodiments and all such variations and modifications that fall within the spirit and scope of the inventive concepts.