Abstract:
A screen assembly configured to separate coarse (larger) and fine (small) materials from an effluent flow. The assembly includes a plurality of bars having different heights. The bars are arranged to form larger spaces for separating coarser material from the effluent flow, and arranged to form smaller spaces for separating finer materials from the effluent flow. The effluent flows into the larger spaces first, and subsequently flows out of the smaller spaces. The assembly includes a cleaning device operable to remove the materials from both the large and small spaces.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the invention generally relate to a screen assembly operable to separate both coarse (e.g. large) and fine (e.g. small) materials from an effluent stream. 
         [0003]    2. Description of the Related Art 
         [0004]    Existing screen assemblies are generally configured to separate debris greater than only one particular size from an effluent stream. The screen assemblies generally include numerous bars that are evenly spaced apart. As the effluent passes through the spaces between the bars, debris in the effluent that is too large to pass through the spaces are retained by the bars and then removed from the assembly. 
         [0005]    Multiple screen assemblies are used to separate out different sizes of debris from the effluent stream. For example, one screen assembly having a larger spacing between the bars is used to separate large debris from the effluent stream, and a second, separate screen assembly having a smaller spacing between the bars is used to separate smaller sized debris from the effluent stream. The two separate screen assemblies are arranged to remove the large debris first and then remove the smaller debris after. 
         [0006]    The reason for using two separate assemblies is because the screen with the smaller bar spacing can be damaged by large debris, and is more easily clogged by large debris. The advantage of the smaller bar spacing, however, is a higher degree of debris capture. Having two separate screen assemblies increases costs due to the space required for the layout, as well as the double maintenance and assembly requirements. 
         [0007]    Therefore, there is a need for a new and improved screen assembly. 
       SUMMARY OF THE INVENTION 
       [0008]    Embodiments of the invention include a screen assembly comprising a support member; a plurality of first bars coupled to the support member; a plurality of second bars coupled to the support member, wherein the second bars have a height different than a height of the first bars, and wherein the first and second bars are arranged to remove material from a fluid stream flowing between the first and second bars; and a cleaning device operable to remove material from the first and second bars. 
         [0009]    Embodiments of the invention include a screen assembly comprising a support member; a plurality of first and second bars coupled to the support member and arranged such that fluid flows into larger spaces formed between the first bars and flows out of smaller spaces formed between the first and second bars; and a cleaning device operable to remove material separated from the fluid flow by the first and second bars. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    So that the manner in which the above recited features of the invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0011]      FIG. 1  is a front view of a screen assembly. 
           [0012]      FIG. 2A  is a side sectional view of the screen assembly taken along line  2 A- 2 A illustrated in  FIG. 1 . 
           [0013]      FIG. 2B  is a sectional view of the screen assembly taken along line  2 B- 2 B illustrated in  FIG. 2A . 
           [0014]      FIG. 2C  is a sectional view of the screen assembly taken along line  2 C- 2 C illustrated in  FIG. 2A . 
           [0015]      FIG. 2D  is an enlarged portion of the screen assembly illustrated in  FIG. 2C . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Embodiments of the invention relate to a screen assembly configured to separate materials (such as debris or solids) of different sizes from an effluent stream (such as a liquid stream). In particular, the screen assembly may include a plurality of bars spaced apart for permitting effluent flow through the bar spaces. Materials, such as debris, that are too large to pass through the bar spaces are captured by the upper surfaces of the bars and/or the spaces between the bars. The bars have different heights to capture materials of different sizes. The materials captured by the bars are removed by a cleaning device, such as a rake or comb, that moves along adjacent the upper surfaces of the bars. 
         [0017]      FIG. 1  is a front view of a screen assembly  100 . The screen assembly  100  may generally include a support structure  10  (such as a frame), a plurality of bars  20 , and one or more cleaning devices  30 . The screen assembly  100  may be disposed in a channel or waterway having a width similar to the width “W” of the screen assembly  100 . An effluent stream may flow through the channel or waterway, and flow through the screen assembly  100  as indicated by flow arrow “F” illustrated in  FIG. 2A . Materials (such as debris) in the effluent stream are captured and separated by a plurality of bars  20  of the screen assembly  100 . The effluent stream may have a depth similar to the length “L” of the bars  20  illustrated in  FIG. 2A . Each cleaning device  30  may move along the bars  20  to remove the materials captured by the screen assembly  100 . 
         [0018]      FIG. 2A  is a sectional view of the screen assembly  100 . As illustrated, one or more support members  25  (such as rods) are used to support and/or connect the bars  20  together. The bars  20  may be evenly spaced apart, or may have a different spacing between one or more of the bars  20 . The bar spacing determines the sizes of materials that may flow, and thus the sizes of materials that may not flow, through the screen assembly  100 . One bar  21  is shown, having a lower end coupled to the support structure  10 , and vertically oriented at a slight angle to an upper free end. 
         [0019]    Each cleaning device  30  may include a plurality of cleaning members  31 ,  32  (such as fingers) that are used to remove materials captured by the bars  20 , and thereby permit unobstructed effluent flow through the screen assembly  100 . The cleaning devices  30  may lift the material to a discharge bin or other similar waste removal container coupled to or disposed adjacent to the screen assembly  100 . The cleaning devices  30  may be movable along a track  40  using methods known in the art, such as by motors, gears, rollers, chains and/or other similar operating systems. The track  40  may include a continuous loop so that the cleaning devices  30  may be operated continuously to prevent clogging of the screen assembly  100 . 
         [0020]      FIGS. 2B and 2C  illustrate sectional views of the screen assembly  100 .  FIG. 2B  illustrates a view of one of the cleaning devices  30  from below, and  FIG. 2C  illustrates a view of two of the cleaning devices  30  from above. Each cleaning device  30  may include one or more connection members  33  for securing the body of the cleaning device  30  to the track  40 . The cleaning members  31 ,  32  may also be coupled to the body of the cleaning device  30  adjacent to each other, such as by threaded, bolted, welded, or other similar connections known in the art. The cleaning members  31 ,  32  are configured to remove material from the spaces between bars  20 . In particular, the cleaning members  31  may be larger in length, width, and/or height than the cleaning members  32  to remove material from the bar spaces of one desired size, while the cleaning members  32  may include a different size/shape to remove material from bar spaces of a different size. 
         [0021]    In one embodiment, each cleaning device  30  may be configured to simultaneously remove material from all of the spaces between the bars  20 . In one embodiment, one cleaning device  30  may be configured to remove material from a first set of bar spaces, and a second cleaning device  30  may be configured to remove material from a second set of bar spaces. In one embodiment, the cleaning members  31  may be configured to remove material from one or more bar spaces, and the cleaning members  32  may be configured to remove material from one or more other bar spaces. In one embodiment, the cleaning members  31 ,  32  may jointly or individually remove material from all or a portion of one or more of the bar spaces. 
         [0022]      FIG. 2D  illustrates the spaces between the bars  20  with the cleaning device  30  removed for clarity according to one embodiment. A first plurality of bars  21  may include a first height H 1 , and a second plurality of bars  22  may include a second height H 2  that is different than, such as less than, the first height H 1 . The first plurality of bars  21  may be evenly spaced apart from each other to form a space  23 . In one embodiment, the spaces  23  may have a width of about 10-12 millimeters to about 50-75 millimeters. The second plurality of bars  22  may be disposed between the bars  21 , thereby forming a space  24  between adjacent bars  21 ,  22 . In one embodiment, the spaces  24  may have a width of about 2-5 millimeters to about 10-25 millimeters. Each space  23  formed by two adjacent bars  21  may be integral with or in communication with two spaces  24  formed by one bar  22  disposed between the two adjacent bars  21 . Fluid may flow into the spaces  23  before flowing into spaces  24 . Fluid may flow into the spaces  23  and may flow out of the spaces  24  in the direction of flow arrows F through the screen assembly  100 . 
         [0023]    Material, such as debris, in the effluent stream may be filtered out by the bars  21 ,  22 . Material that is too large to flow into the spaces  23  may be captured by the bars  21 , and may be prevented from contacting the bars  22 . Material that can flow into the spaces  23  but that is too large to flow into the spaces  24  may be captured by the bars  21 ,  22 . Depending on the size/shape/type of materials in the effluent stream, some material may flow into the spaces  23  but may be captured by the sidewalls of the bars  21  without contacting the bars  22 . Similarly, some material may flow into the spaces  24  but may be captured by the sidewalls of the bars  21 ,  22  rather than flow through the screen assembly  100 . In this manner, the screen assembly  100  is configured to separate materials of different sizes from an effluent stream using a single screen unit. 
         [0024]    In one embodiment, the bars  21  can remove larger or coarse sized material, and the bars  21 ,  22  can remove smaller or fine sized material. In one embodiment, the bars  22  may be disposed between two, three, four, or more bars  21  and vice versa. In one embodiment, the bars  21 ,  22  may be arranged in any order to form one or more spaces  23 ,  24  and/or other sized spaces configured to separate materials of different sizes from an effluent stream. In one embodiment, a third, fourth, or fifth plurality of bars may be used having heights that are different, such as less than or greater than, the heights of the bars  21 ,  22 , thereby forming other spaces with the bars to capture even more materials of different sizes using a single screen unit. In one embodiment, the bars may be symmetrically or asymmetrically spaced apart. In one embodiment, the lengths and/or widths of one or more of the bars may be the same as or different than one or more of the other bars. 
         [0025]    As stated above, the cleaning devices  30  may be continuously operated to remove materials from the effluent stream that are captured by the bars  20  and thereby clean the screen assembly  100 . The cleaning devices  30  may be moved along the longitudinal length of the bars  20  such that the cleaning members  31  extend through spaces  23  and into spaces  24 , and such that the cleaning members  32  extend into spaces  23 . The combination of the cleaning members  31 ,  32  may simultaneously remove materials disposed on the bars  20  and within both spaces  23 ,  24 . The cleaning members  31 ,  32  may move or lift the materials along the longitudinal length of the bars  20 , out of the effluent flow, and into a discharge bin or other similar waste removal container coupled to or disposed adjacent to the screen assembly  100 . 
         [0026]    In one embodiment, the cleaning devices  30  may include one or more cleaning members  31 ,  32  dimensioned/configured to remove materials separated by any arrangement and/or spacing of the bars described above. In one embodiment, the cleaning members  31 ,  32  may be symmetrically or asymmetrically spaced apart. In one embodiment, the heights, lengths, and/or widths of one or more of the cleaning members  31 ,  32  may be the same as or different than one or more of the other cleaning members  31 ,  32 . 
         [0027]    While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.