Abstract:
A screen intake apparatus has a concrete platform resting on a water source floor. A screen intake anchors on the platform and forms a half cylinder thereon. A barrier at one end of the platform in divides the flow of water. The screen intake has a half-cylindrical body and half-cylindrical screens. Transition walls in the screen intake divide the body&#39;s hollow and the screens&#39; interiors, and at least one flow modifier communicates the interior with the hollow. These flow modifiers also form a half cylinder with the platform. A manifold in the screens receives a supply of air to clear debris. Forming a half-cylinder, the screen intake on the platform can have a much lower profile for the water source than the normal cylindrical screens, which require half of its diameter in clearance above and below.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of U.S. patent application Ser. No. 13/658,716, filed Oct. 23, 2012, which is a continuation of U.S. patent application Ser. No. 12/951,217, filed Nov. 22, 2010, issued as U.S. Pat. No. 8,297,448, the contents of all of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    Drinking water plants, manufacturing plants, irrigation systems, and power generation facilities use large quantities of water for their operation. To collect the water, screen intakes are used in various bodies of water. As shown in  FIG. 1A , one common type of screen intake  10  has a tee configuration with two screens  12 A-B on opposing ends of a central body  14 . An outlet  16  connects from the central body  14  for connecting to components of a screen intake system. 
         [0003]    The screen intake  10  must be designed to protect aquatic life and to prevent buildup of debris along the length of the intake&#39;s screens  12 A-B. To do this, the flow velocity through the screens should be kept below a maximum peak level, which may be about 0.5 f/s. One way to reduce the flow resistance and control the flow velocity evenly across the screen&#39;s surface is to use flow modifiers inside the screen intake. For example, Johnson Screens—the assignee of the present disclosure—improves flow uniformity using flow modifiers as disclosed in U.S. Pat. Nos. 6,051,131 and 6,712,959, which are incorporated herein by reference in their entireties. 
         [0004]    When used in a source waterway, the screen intakes  10  must be arranged with no less than a minimum amount of distance surrounding it. As shown in  FIG. 1B , the standard intake  10  requires clearance above and below the screen intake  10  that is at least half of the intake&#39;s diameter. For example, a screen intake  10  having a 24-in. diameter needs 12-in. clearance above and below the intake  10  for proper operation. Thus, the 24-in. diameter screen intake  10  can mount in water with a total minimum depth of 48-in. (4-ft.). 
         [0005]    Available source waters for intake systems are becoming shallower. For shallow applications, flat screens, velocity caps, or cribbing has been used in the past to intake source water. These traditional approaches sit flat on the bottom of the source water. Being flat, however, these types of screens can have problems with deflection and strength when subjected to flow and debris. In addition, these types of screens can be difficult to keep clear of debris. Finally, flat screens can have uneven flow distribution over the screen&#39;s surface area, which can be problematic during operation. 
         [0006]    The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above. 
       SUMMARY 
       [0007]    A screen intake apparatus has a base that disposes on a floor of a water source. The base can be a concrete slab or platform resting on the floor and having a top surface. A screen intake disposes on the base and forms a half cylinder thereon. Anchors can affix edges of the screen intake to the top surface of the base. In a river or application with strong currents, the base would preferably have a barrier disposed at one end thereof in a path of flow of the source water to deflect debris and silt from the screen intake. 
         [0008]    The screen intake has a body with first and second screens on its ends. Each of the screens forms a half cylinder on the base and defines an interior therein. The interiors communicate with the hollow of the body so the source water entering the screen passes to the body and out a common outlet. 
         [0009]    The first and second screens each have a screen sidewall, a closed distal end, and an open proximal end. The open proximal end attaches to the body, while the closed distal ends have end walls that define a half circle. Preferably, the screen intake has transition walls disposed between the hollow of the body and the interiors of the screens. At least one flow modifier disposes in each of the transition walls. The flow modifier has one open end communicating with the interior of the screen and has another open end communicating with the hollow of the body. The flow modifier can have two or more flow modifiers nested inside one another, and these flow modifiers also form a half cylinder with the base. 
         [0010]    The screen intake can also have a manifold disposed in the screens for receiving a supply of air used to clear the screens of debris. Construction of the screens can use ribs disposed along a length of the screen and can have wires disposed across the ribs. Overall, the half cylinder screen intake mounted on the top surface of the base can provide all the attributes of a normal intake screen but provide a very low profile for shallower applications. 
         [0011]    The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1A  is a perspective view of a screen intake according to the prior art. 
           [0013]      FIG. 1B  is a view of a prior art screen intake system used in a shallow water source, such as a river. 
           [0014]      FIG. 2  is a plan view of a screen intake system according to the present disclosure. 
           [0015]      FIGS. 3A-3C  show plan, side, and end views of a screen intake on a platform for the disclosed intake system. 
           [0016]      FIGS. 4A-4B  show a 24-inch tee screen intake of the prior art compared to a 24-inch half-screen intake according to the present disclosure. 
           [0017]      FIG. 5  shows a portion of a screen section for the screen intake of the present disclosure. 
           [0018]      FIGS. 6A-6C  show plan and end views of one type of screen intake for the disclosed system. 
           [0019]      FIGS. 7A-7B  show plan and end views of a screen intake with a first type of flow modifier. 
           [0020]      FIGS. 8A-8B  show plan and end views of a screen intake with a second type of flow modifier. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    A screen intake system  50  in  FIG. 2  has two screen intakes  100 , although more or less could be used. Each screen intake  100  positions on a base or platform  60  disposed in the flow of a water source, such as a river.  FIGS. 3A and 3B  show top and side views of the platform  60 . The platform  60  can be composed of a concrete slab or the like and can rest on the floor of the water source. As shown in  FIG. 3B , the platform  60  preferably extends at least 3-4 inches above the floor of the water source. 
         [0022]    In a river or other application where a current is present, the front end of each platform  60  has a profiled barrier  62  to cut the water flow ahead of the screen intake  100 . The profiled barrier  62  is preferably angled at its front face and divides the passage of water, debris, and silt. In addition as shown in  FIG. 3B , the profiled barrier  62  preferably extends to about the height of the screen intake  100  resting on the platform  60 . The barrier  62  can be separately constructed from the platform  60  or can be integrally formed therewith. As an alternative to the barrier  62 , the screen intake  100  can be provided with a profiled end. 
         [0023]    As shown in  FIG. 3A , the screen intake  100  can have a tee configuration with first and second screen sections  110 A-B connected on opposing ends of a central body  120 . End walls  115 A-B close off the ends of the screen sections  110 A-B, and a central outlet  130  extends from the central body  120 . Alternatively, the screen intake  100  can have one screen section  110  connected to a body  120  with an outlet  130 , while the other end of the body  120  is closed and lacks a second screen section  110 . 
         [0024]    As shown in  FIG. 3C , the screen intake  100  defines a half cylinder on the top surface of the platform  60 . In general, the screen intake  100  has half-cylinder screens for the screen sections  110 A-B along with half circle end walls  115 A-B. The body  120  can have a half-cylinder sidewall, although another configuration could be used. Each of these components ( 110 ,  115 ,  120 ) can be affixed together using techniques known in the art. In one arrangement, the screen intake  100  has a flat bottom component that affixes to the edges of these interconnected components ( 110 ,  115 ,  120 ). Such a flat bottom can rest against the top surface of the platform  60 , while anchor bolts  64  or the like are used to affix the screen intake  100  to the platform  60 . 
         [0025]    Alternatively, the intake  100  may lack an overall flat bottom component that affixes to the edges of the connected components ( 110 ,  115 ,  120 ). Instead, free edges of the interconnected body  120 , screen sections  110 A-B, and end walls  115 A-B can fit directly against the platform  60  and can attach thereto using the anchor bolts  64  or the like. For example, the platform  60  can have a width and a length that is slightly larger than the screen intake  100  by about 3-in. or so. The platform  60  can have holes defined all around its perimeter for concrete anchor bolts  64  that hold the screen intake  100  onto the platform  60 . 
         [0026]    In yet another arrangement, the screen intake  100  can be a cylindrical (or at least partial cylindrical) screen intake partially embedded in the material of the platform  60 . In this arrangement, the full or partial cylindrical screen intake  100  can be embedded in the concrete of the platform&#39;s slab when constructing the platform  60  using techniques available in the art. 
         [0027]    In assembly, the screen intake  100  can be preconstructed on the platform  60  on land, and both components  60 / 100  can be sunk to the floor of the water source. Alternatively, the screen intake  100  and platform  60  can be separately constructed. The platform  60  can be placed on the water source&#39;s floor, and the screen intake  100  can be affixed to the top surface of the platform  60  with the anchors  64 . These and other forms of construction can be used for the screen intake system  50 . 
         [0028]    As shown in  FIG. 2 , the outlets  130  of the screen intakes  100  connect by piping  52  to a facility (not shown) configured to use the intake water. Preferably, the intakes  100  and platforms  60  are staggered in relation to one another so as not to lie in each other&#39;s wakes. The screen intake  100  mounted toward the bottom of the source water reduces the depth needed to take in the same flow as a conventional screen. For example, the screen intake  100  can define a 24-in. diameter (12-in. radius). This requires a 12-in. clearance above the screen intake  100  for proper operation. 
         [0029]    As shown in  FIG. 4A , for example, the screen intake  100  of the present disclosure with a 24-in. diameter d can operate in a total minimum operational depth D 1  of only about 20-in. This offers advantages over conventional systems using a 24-in. diameter tee screen  10  of the prior art as shown for comparison in  FIG. 4B . Such a conventional tee screen  10  of the prior art needs a 48-in depth D 2  of water. 
         [0030]    As shown in  FIGS. 3A-3B , each of the screen sections  110 A-B defines a plurality of slots for entry of water into the screen sections  110 A-B. The slots can be either transverse or parallel to the axis of the screen sections  110 A-B. Preferably, spaced wraps of profiled wire form the slots of the screen sections  110 A-B, although the screen sections  110 A-B can also be a solid pipe member with slots formed therein. The screen sections  110 A-B can keep flow distribution even over the screen&#39;s surface area. The curved, rounded screen sections  110 A-B also provide strength to the screen intake  100  while offering a low profile. Thus, the curved screen sections  110 A-B may not need additional structural support in their interiors to support the screen surfaces. 
         [0031]    As shown in  FIG. 5 , one form of construction for the screen sections  110  has profiled wires  112  and support bars  114 . In one implementation, the support bars  114  run along the length of the screen section  100 , and the profiled wires  112  circumferentially wrap and weld to the support bars  114  to form the screen section  110  using techniques known in the art. The profiled wires  112  are preferably wedged or Vee-shaped with a wider base of the wire  112  facing outward to enhance the sliding of debris over the screens&#39; surfaces. For example, the profiled wire  112  can be VEE-WIRE® available from Johnson Screens. (VEE-WIRE is a registered trademark of Weatherford/Lamb, Inc.). 
         [0032]    Another example of a screen intake  100  is shown in  FIGS. 6A-6C . This intake  100  has the screen sections  110 A-B, end walls  115 A-B, central body  120 , and outlet  130  as before. The intake  100  also defines a half cylinder as shown in  FIG. 6B-6C . The screen intake  100  can have a closed or open bottom  117  as discussed previously for resting on the top surface of a platform. 
         [0033]    In addition to these features, the screen intake  100  has an air backwash pipe  140  and a header  142  provided for backwashing the screen intake  100  with an air burst to clear debris. The air backwash header  142  connects to the air backwash pipe  140  and disposes inside the screen sections  110 A-B and the body  120 . When used, the pipe  140  and header  142  allow the screen intake  100  to be backwashed with an airburst to clear debris. These features can be based on Johnson Screen&#39;s Hydroburst System. In general, the Hydroburst system uses a compressor, a tank, valves, and controls to generate a blast of air in the screen sections  110 A-B. Done periodically, the air blast flushes debris away from the screen&#39;s surfaces. 
         [0034]    In addition to the backwash system, the intake  100  of the present disclosure can include flow modifiers disposed internally in the screen sections  110 A-B. The flow modifiers can be used with the backwash system or alone. Further details of the flow modifiers are provided below with reference to  FIGS. 7A-7B  and  8 A- 8 B. 
         [0035]    The screen intake  100  illustrated in  FIGS. 7A-7B  and  8 A- 8 B each has a tee configuration with first and second screens  110 A-B connected on opposing ends of the central body  120 . The central body  120  defines a hollow  122  therein and has a half-cylindrical sidewall  124  and opposing transition walls  126 A-B. The outlet conduit  130  connects to an opening  132  in the sidewall  124  and has a flange for connecting to other components of a fluid intake system (not shown). Both transition walls  126 A-B have a central opening  128  receiving flow from one of the screen sections  110 A-B. 
         [0036]    Both screen sections  110 A-B have open ends connected to the body&#39;s transition walls  126 A-B and have closed ends walls  115 A-B that may or may not be shaped to deflect debris. Each of the screen sections  110 A-B defines a half cylinder and defines a plurality of slots for entry of water into the screen sections  110 A-B as described previously. Again, the slots can be either transverse or parallel to the axis of the screen section  110 A-B. Preferably, spaced wraps of profiled wire  112  form the slots of the screens  110 A-B, although the screens  110 A-B can also be a solid pipe member with slots formed therein. 
         [0037]    The central passages  128  in the transition walls  126 A-B may be sufficient to control the flow velocity at the screen&#39;s surfaces to maintain a preferred surface flow velocity. However, each transition wall  126 A-B preferably has a flow modifier  150  disposed in its central opening  128  to further control the flow velocity. In general, the screen intake  100  can use flow modifiers  150  having one or more pipes disposed in the openings  128  and partially inside the hollows of the screen sections  110 A-B to communicate fluid from inside the screen sections  110 A-B, through the openings  128 , and into the hollow  122  of the central body  120 . 
         [0038]    The screen intake  100  embodied in  FIGS. 7A-7B  uses single flow pipes  160  for the flow modifier  150  disposed in the openings  128 . The screen intake  100  embodied in  FIGS. 8A-8B  uses double flow pipes  170  and  180  nested inside one another in the openings  128 . In both arrangements, the pipes  160  and  170 / 180  of the flow modifiers  150  can actually be half cylinders with open or closed bottom surfaces, although full cylindrical pipes can be used off center in openings  128  of the transition walls  126 A-B. 
         [0039]    The screen intake  100  and flow modifiers  150  of  FIGS. 7A-7B  and  8 A- 8 B are designed to reduce the entrance velocity at the screens&#39; slots to a preferred peak, which may be about 0.135 m/s or 0.5 f/s in some implementations. A lower entrance velocity protects surrounding aquatic life and prevents debris clogging. Designers configure the lengths, diameters, flow areas, and other variables of the flow modifiers&#39; pipes  160  and  170 / 180  to keep the average flow through the screens&#39; surfaces as close to the allowable peak flow velocity and as uniformly distributed across the screens&#39; surfaces as possible. Where the flow modifier uses two pipes  170 / 180  as in  FIG. 8A , for example, the larger diameter pipe  170  may be about 50% of the screen section  110 &#39;s diameter and may be about 16% of the length of the screen  110 . The smaller diameter pipe  180  nested within the outer pipe  170  may have a diameter about 70% that of the outer pipe  170  and may have a length which extends about 67% of the length of the screen  110 . Further details related to the design of the flow modifiers  150  are disclosed in U.S. Pat. No. 6,051,131, which is incorporated herein in its entirety. 
         [0040]    As used herein and in the claims, terms such as cylinder and cylindrical are meant to be generic and refer to a general geometric shape known by that name. Terms such as half cylinder and half-cylindrical refer to a division of such a general geometric shape along a longitudinal axis and need not be precisely half. Thus, the sidewall of the cylinder and half cylinder as used herein can be defined by a radius as in the standard geometric shape. However, the sidewall of the cylinder and half cylinder as used herein can be defined by multiple angled surfaces, a cycloidal surface, an elliptical surface, an oval surface, a parabolic surface, or any other curved surface. The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.