Abstract:
A heating and/or air conditioning system comprising a blower for generating an air stream and a heat exchanger unit for heating or cooling the air stream includes a diffuser which is positioned between the blower and the heat exchanger unit and which comprises a plurality of vertically spaced diffuser plates, each of which includes an upstream edge and a downstream edge. The vertical distance between the downstream edges of at least an adjacent pair of diffuser plates is greater than the vertical distance between the upstream edges of the pair of diffuser plates. Thus, the diffuser diffuses the air stream vertically prior to the air stream entering the heat exchanger unit.

Description:
[0001]    This application is based on U.S. Provisional Patent Application No. 61/340,362, which was filed on Mar. 15, 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an air diffuser for a heating and air conditioning system. More particularly, the invention relates to a diffuser for an aircraft heating and air conditioning system. 
         [0003]    Conventional heating and air conditioning (“HVAC”) systems include a blower for generating a stream of air and a heat exchanger unit for heating or cooling the air. The efficiency of an HVAC system is affected by the degree of heat transfer between the air stream and the heat exchanger unit. The more evenly and uniformly the air can be made to flow over the entire surface of the heat exchanger unit, the better will be the heat transfer between the air and the heat exchanger unit. 
         [0004]    In conventional HVAC systems, the air stream exiting the blower often does not flow uniformly over the heat exchanger unit. Instead, the air stream tends to flow mainly through only a portion of the surface of the heat exchanger unit. Consequently, temperature differentials are created within the overall air stream which tend to reduce the efficiency of the system. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with the present invention, these and other limitations in the prior art are addressed by providing a novel diffuser for a heating and/or air conditioning system which includes a blower for generating an air stream and a heat exchanger unit for heating or cooling the air stream. The diffuser is positioned between the blower and the heat exchanger unit and comprises a plurality of vertically spaced diffuser plates, each of which includes an upstream edge and a downstream edge. The vertical distance between the downstream edges of at least an adjacent pair of diffuser plates is greater than the vertical distance between the upstream edges of said pair of diffuser plates. Thus, the diffuser diffuses the air stream vertically prior to the air stream entering the heat exchanger unit. 
         [0006]    In accordance with one embodiment of the invention, the diffuser further comprises at least two horizontally spaced support brackets, each of which extends generally vertically through the diffuser plates and includes an upstream end and a downstream end. The horizontal distance between the downstream ends of the support brackets is greater than the horizontal distance between the upstream ends of the support brackets. Thus, the diffuser diffuses the air stream both vertically and horizontally prior to the air stream entering the heat exchanger unit. 
         [0007]    These and other objects and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings. In the drawings, the same reference numbers may be used to denote similar components in the various embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is cross sectional representation of an exemplary aircraft heating and air conditioning system incorporating the diffuser of the present invention; 
           [0009]      FIG. 2  is a perspective view of the upper diffuser sub component of the diffuser shown in  FIG. 1 ; 
           [0010]      FIG. 3  is a front elevation view of the upper diffuser sub shown in  FIG. 1 ; 
           [0011]      FIG. 4  is a side elevation view of the upper diffuser sub shown in  FIG. 1 ; 
           [0012]      FIG. 5  is a front elevation view of the upper flange bracket component of the upper diffuser sub shown in  FIG. 1 ; 
           [0013]      FIGS. 6A and 6B  are top plan and side elevation views, respectively, of the top diffuser plate component of the upper diffuser sub shown in  FIG. 1 ; 
           [0014]      FIGS. 7A and 7B  are top plan and side elevation views, respectively, of the middle diffuser plate component of the upper diffuser sub shown in  FIG. 1 ; 
           [0015]      FIGS. 8A and 8B  are top plan and side elevation views, respectively, of the bottom diffuser plate component of the upper diffuser sub shown in  FIG. 1 ; 
           [0016]      FIG. 9  is a perspective view of the lower diffuser sub component of the diffuser shown in  FIG. 1 ; 
           [0017]      FIG. 10  is a front elevation view of the lower diffuser sub shown in  FIG. 1 ; 
           [0018]      FIG. 11  is a side elevation view of the lower diffuser sub shown in  FIG. 1 ; 
           [0019]      FIG. 12  is a front elevation view of the lower flange bracket component of the lower diffuser sub shown in  FIG. 1 ; 
           [0020]      FIGS. 13A and 13B  are top plan and side elevation views, respectively, of the top diffuser plate component of the lower diffuser sub shown in  FIG. 1 ; 
           [0021]      FIGS. 14A and 14B  are top plan and side elevation views, respectively, of the middle diffuser plate component of the lower diffuser sub shown in  FIG. 1 ; 
           [0022]      FIGS. 15A and 15B  are top plan and side elevation views, respectively, of the bottom diffuser plate component of the lower diffuser sub shown in  FIG. 1 ; 
           [0023]      FIG. 16  is a perspective view of a second embodiment of an aircraft heating and air conditioning system incorporating the diffuser of the present invention; 
           [0024]      FIG. 17  is a partial side elevation view of the heating and air conditioning system taken along line A-A of  FIG. 16 ; 
           [0025]      FIG. 18  is a front sectional view of the heating and air conditioning system taken along line B-B of  FIG. 16 ; 
           [0026]      FIG. 19  is a partial perspective view of the blower and diffuser assembly of the heating and air conditioning system shown in  FIG. 16 ; 
           [0027]      FIG. 20  is a side elevation view of the blower and diffuser assembly shown in  FIG. 19 , with a portion of the blower throat removed to better show the diffuser component; and 
           [0028]      FIG. 21  is a top plan view of the blower and diffuser assembly shown in  FIG. 19 , with a portion of the blower throat removed to better show the diffuser component. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Referring to  FIG. 1 , the diffuser of the present invention, generally  10 , is shown installed in an exemplary aircraft heating and air conditioning system  12 . The heating and air conditioning system  12  comprises a diverging inlet plenum  14 , a blower  16  which is connected to the inlet of the inlet plenum, a heat exchanger unit  18  which is connected to the outlet of the inlet plenum, a converging outlet plenum  20  which is connected to the outlet of the heat exchanger unit, and an air supply conduit  22  which is connected to the outlet of the outlet plenum. 
         [0030]    In operation of the heating and air conditioning system  12 , the blower  16  generates a flow of air which is directed into the inlet plenum  14  and over the diffuser  10 . After exiting the diffuser  10 , the air flows through the heat exchanger unit  18 , where it either absorbs heat from a relatively high temperature heat source or dissipates heat into a relatively low temperature heat sink, depending on whether the heating and air conditioning system  12  is operating as a heater or a cooler, respectively. After the air passes through the heat exchanger unit  18 , it converges in the outlet plenum  20  and enters the air supply conduit  22 , which is typically connected to an aircraft in order to heat or cool the cabin as the aircraft is parked on the tarmac. 
         [0031]    In accordance with the present invention, the diffuser  10  serves to spread the air flow both vertically and horizontally over a large portion of the cross sectional area of the heat exchanger unit  18  in order to improve the efficiency of the transfer of heat between the air and the heat exchanger unit. 
         [0032]    The diffuser  10  may be constructed as a single unit. However, in order to simplify assembly of the diffuser  10  with the heating and air conditioning system  12 , the diffuser may be divided into an upper sub  24  and a lower sub  26 . 
         [0033]    Referring to  FIGS. 2 through 5 , the upper sub  24  includes an upper flange bracket  28  in which top, middle and bottom diffuser plates  30 ,  32  and  34  are mounted. As shown most clearly in  FIG. 5 , the upper flange bracket  28  comprises a generally C-shaped body  36  in which opposing pairs of top, middle and bottom slots  38 ,  40  and  42  are formed. The downstream side edges of the top, middle and bottom diffuser plates  30 ,  32 ,  34  are received and preferably welded in the top, middle and bottom slots  38 ,  40 ,  42 , respectively, in order to connect the diffuser plates to the upper flange bracket  28 . The body  36  also includes a number of holes  44  which align with corresponding holes in the adjacent flange of the inlet plenum  14  order to secure the upper sub  24  to the heating and air conditioning unit system. 
         [0034]    An embodiment of the top diffuser plate  30  is shown with its representative dimensions in  FIGS. 6A and 6B . Likewise, embodiments of the middle and bottom diffuser plates  32 ,  34  are shown with their representative dimensions in  FIGS. 7A and 7B  and  FIGS. 8A and 8B , respectively. As shown in these figures, when viewed together with  FIG. 4 , each of the diffuser plates  30 ,  32 ,  34  comprises a generally flat body  46  which extends from the upstream edge of the diffuser plate to approximately the upper flange bracket  28 , and a lip  48  which angles downwardly from the downstream edge of the body to the downstream edge of the diffuser plate. 
         [0035]    The upper sub  24  may also include two transverse support brackets  50  and two transverse stiffener brackets  52 . As shown most clearly in  FIGS. 2 ,  4  and  6 - 8 , each support bracket  50  is received and secured in a corresponding slot  54  which is formed in the body  46  of each diffuser plate  30 ,  32 ,  34 . Similarly, each stiffener bracket  52  is received and secured in a corresponding elongated aperture  56  which is formed in the body  54  of each diffuser plate  30 ,  32 ,  34  proximate the upstream edge of the diffuser plates. 
         [0036]    As shown most clearly in  FIG. 4 , the diffuser plates  30 ,  32 ,  34  are mounted and connected together such that the vertical distance between adjacent diffuser plates at their downstream edges, or at least at the upper flange bracket  28 , is greater than the vertical distance between adjacent diffuser plates at their upstream edges. This configuration serves to diffuse the air stream vertically. Also, as a result of the slots  54  being oriented at an angle relative to the longitudinal centerlines of the diffuser plates  30 ,  32 ,  34  as shown in  FIGS. 6-8 , the support brackets  50  are similarly oriented such that the distance between their downstream ends is greater than the distance between their upstream ends. Consequently, the support brackets  50  will act to diffuse the air stream horizontally. 
         [0037]    The structure of the lower diffuser sub  26  is very similar to that of the upper diffuser sub  24 . Referring briefly to  FIGS. 9-11 , the lower diffuser sub  26  comprises a lower flange bracket  58  in which top, middle and bottom diffuser plates  60 ,  62  and  64  are mounted. An embodiment of the lower flange bracket with its representative dimensions is shown in  FIG. 12 . Embodiments of the top, middle and bottom diffuser plates  60 ,  62 ,  64  with their corresponding representative dimensions are shown in  FIGS. 13A and 13B ,  FIGS. 14A and 14B , and  FIGS. 15A and 15B , respectively. 
         [0038]    As with the upper diffuser sub  24 , the lower diffuser sub  26  includes two support brackets  66  which are similar to the support brackets  50  and two stiffener brackets  68  which are similar to the stiffener brackets  52 . These support and stiffener brackets  66 ,  68  are received in and connected to corresponding slots and apertures in the diffuser plates  60 ,  62  and  64  in a manner similar to the support and stiffener brackets  50 ,  52 . 
         [0039]    In order to assemble the diffuser  10  with the heating and air conditioning unit  12 , the lower diffuser sub  26  is inserted into the inlet plenum  14  and bolted to the downstream flange  70  of the inlet plenum ( FIG. 1 ). The upper diffuser sub  24  is then inserted into the inlet plenum  14  above the lower diffuser sub  26  and bolted to the downstream flange  70 . In order to facilitate the assembly of the upper diffuser sub  24  with the lower diffuser sub  26 , each of the support brackets  50  of the upstream diffuser sub may be provided with a transverse lower foot  72  ( FIG. 2 ), each of the support brackets  66  of the lower diffuser sub may be provided with a transverse upper foot  74  ( FIG. 9 ), and these feet may be secured together after the upper diffuser sub is positioned on the lower diffuser sub. 
         [0040]    A second embodiment of an aircraft heating and air conditioning system in which the diffuser  10  may be incorporated is illustrated in  FIGS. 16 through 18 . The heating and air conditioning system of this embodiment, which is indicated generally by reference number  100 , includes a blower  102  for generating a flow of air to either heat or cool an aircraft. The blower  102  comprises a diverging throat  104  having a generally circular outlet flange  106 . The outlet flange  106  is connected to an upstream end wall  108  of a diverging inlet plenum  110 . The outlet of the inlet plenum  110  is connected to one side of a heat exchanger unit  112 , the opposite side of which is connected to a converging outlet plenum  114 . The downstream end of the outlet plenum  114  comprises an outlet port  116  to which an air supply conduit (not shown) may be connected. Although not required, the components of the heating and air conditioning system  100  may be mounted on a base structure  118 . 
         [0041]    In this embodiment of the invention, the diffuser  10  is mounted in the throat  104  of the blower  102 . Referring also to  FIGS. 19 through 21 , the upstream ends of the upper and lower subs  24 ,  26  are inserted into the throat  104  to position the upper and lower flange brackets  28 ,  58  against the upstream end wall  108  of the inlet plenum  110 . A number of bolts  120  extend through corresponding aligned holes in the upper and lower flange brackets  28 ,  58 , the upstream end wall  108  and the flange  106  to thereby secure the diffuser  10  to the blower  102 . 
         [0042]    In operation of the heating and air conditioning system  100 , the blower  102  generates a flow of air which is directed into the throat  104  and over the diffuser  10 . As the air passes over the diffuser  10 , the upper and lower diffuser plates  30 - 34 ,  60 - 64  spread the air stream vertically and the upper and lower support brackets  50 ,  66  spread the air stream horizontally. The air stream then continues to diffuse both vertically and horizontally as it passes through the inlet plenum  110 . After exiting the inlet plenum  110 , the air flows through the heat exchanger unit  112 , where it either absorbs heat from a relatively high temperature heat source or dissipates heat into a relatively low temperature heat sink, depending on whether the heating and air conditioning system  100  is operating as a heater or a cooler, respectively. After the air passes through the heat exchanger unit  112 , it converges in the outlet plenum  114  and exits the heating and air conditioning system  100  through the outlet port  116 . 
         [0043]    It should be recognized that, while the present invention has been described in relation to the preferred embodiments thereof, those skilled in the art may develop a wide variation of structural and operational details without departing from the principles of the invention. Therefore, the appended claims are to be construed to cover all equivalents falling within the true scope and spirit of the invention.