Abstract:
A method and apparatus for supporting a screen. The apparatus comprising a cylindrical screen for submerging in a fluid, the screen having an inlet pipe for connecting to a piping system, filter members, a first end, a second and a support structure. The support structure is one or more helical members which traverse the screen.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the present invention generally relate to a submerged intake screen. More particularly, embodiments of the present invention relate to a screen having a support structure. More particularly still, the present invention relates to a screen having a helical support structure. 
     2. Description of the Related Art 
     Water collection systems are typically used to provide water to end users such as manufacturing plants, cities, irrigation systems, and power generation facilities located adjacent a body of water such as a river, lake, or salt water bodies. The end users may employ this type of system as an alternative to drilling water well or buying water from a municipality. Additionally, use of these systems may be determined by the location of the end user, for example remote locations where water from a municipal source and/or electrical power to operate pumps is not readily available. These water collection systems have the ability to adapt to varying conditions and deliver water efficiently and economically. 
     These water collection systems typically use an inlet pipe adapted to transport water from a position submerged in the body of water to the end user adjacent the body of water. An inlet pipe is submerged in the body of water and the end of the inlet pipe is typically coupled to an intake screen which typically has a plurality of filtering members, such as ribs, mesh, or perforations disposed on its outer surface. The filtering members are configured to prevent waterborne debris and aquatic life, of a certain size, from entering the inlet pipe. 
     Conventional intake filter assemblies typically include an inlet pipe having an open end surrounded by and coupled to a cylindrical screen, which has a central axis that is the same as a longitudinal axis of the inlet pipe. In this way, the cylindrical screen is concentric with the inlet end of the inlet pipe. A typical intake filter assembly may also include a flow modifier pipe within the inlet pipe and extending beyond the inlet pipe into the cylindrical screen. The flow modifier pipe helps evenly distribute the flow of water through the cylindrical screen over the length of the screen. 
     The flow modifier pipes used now have allowed the overall length of the intake filter to increase while maintaining the intake flow rate below the maximum levels allowed. The increased length of the intake filter has caused structural problems with the intake filter. Previously the intake filters were simply welded to an end cap and a plate connected to the inlet pipe. However, the filter itself is not sufficiently strong enough to support intake and current loads when the length is increased. Attempts have been made to correct this problem using longitudinal support bars in conjunction with optional hoops which follow the filter. However, in order to brace the filter sufficiently a large number of support bars and hoops are required, increasing the overall cost and complexity of each intake filter. 
     Therefore, a need exist for an intake filter having a support structure which is efficient and inexpensive to build, while maximizing the strength of the filter. 
     SUMMARY OF THE INVENTION 
     The present invention generally relates to a submerged filter assembly having a cylindrical screen and a support structure. The cylindrical screen has an inner diameter, a first end and a second end. The support structure supports the cylindrical screen and is configured in a substantially non-longitudinal manner in relation to the screen. 
     The present invention further relates to a method of filtering a medium by submerging an intake filter assembly having a cylindrical screen couplable to a piping system, a primary flow modifier, and a support structure having helical members which support the screen. Thereafter, the medium is flowed past the filter assembly and into the piping system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present 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. 
         FIG. 1  is a front view of a filter assembly with a cut away portion according to an embodiment of the present invention. 
         FIG. 2  is a detail of a support structure connection according to an embodiment of the present invention. 
         FIG. 3  is an cross-sectional end view of a screen and support structure according to one embodiment of the present invention. 
         FIG. 4  is a front view of a filter assembly according to an embodiment of the present invention. 
         FIG. 5  is a front view of a filter assembly according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a front view of a submerged intake filter assembly  100  according to one embodiment of the present invention. The submerged intake screen includes two cylindrical screens  102  coupled together by a connector pipe  104  which is couple to an inlet pipe  106 . The inlet pipe  106  optionally has a flange  108  for easily coupling the screen  100  to a piping system (not shown), for carrying the water to a facility for use. The screens  102  include a series of filter members  110  which run substantially parallel around the circumference of the screen  102 . Although shown as running substantially parallel around the screen  102 , it should be appreciated that the filter members  110  could be arranged in any manner that blocks debris from entering the screen  102 . 
     The intake filter assembly  100  is shown, in  FIG. 1 , with a portion of the filter members  110  cut away. The cut away portion shows the interior of the screen having a primary flow modifier  112 , a secondary flow modifier  114 , a plate  116  which connects the connector pipe  104  to the modifiers  112  and  114 , an end cap  117 , and a support structure  118 . The cut away portion also shows longitudinal supports  120  and circumferential supports  122 , which provide basic support for the screen  102  while holding the filter members  110  in place. Although shown as having longitudinal supports and circumferential supports it should be appreciated that the invention could be practiced with only the longitudinal supports  122 . 
     The support structure  118 , as shown, consists of a series of helical bars  124  which traverse the screen  102 . In one embodiment, a first end  126  of two bars  124  couples to the plate  116  at substantially the same location. The bars  124  then extend toward the end cap  117  in a manner that creates an angle θ 1  between the two bars  124 , as shown in  FIGS. 1 and 2 . The bars  124  are arranged to have the same contour as the screen  102  as the bar traverses the screen  102 . Thus, the bars  124  are in contact with the screen  102  as the bar extends from the first end of the bar  126  to a second end  128  of the bar. The second end  128  of the bar couples to the cap  117 . The bars  124  may be coupled to the plate  116  and the cap  117  by any method known in the art, such as welding, screws, bolts, etc. In one embodiment, the bars  124  at the second end  128  are coupled with a substantially similar angle θ 2  as the angle θ 1  on the first end. With the bars  124  coupled to the plate  116  and the cap  117  at substantially the same location, the bars form a zigzag pattern as they traverse the screen. Although shown as each end of the bars  124  being coupled together at the plate  116  and the cap  117  it should be appreciated that any arrangement could be used so long as the bars  124  traverse the screen  102  in a substantially helical manner. 
     The angles θ 1  and θ 2  can be any angle necessary for the operation. The larger the angle, the longer the bars  124  will need to be in order to traverse a longer section of the screen  102 . Further, any number of angles θ 1  and θ 2  could be used, for example angles θ 1  and/or θ 2  could vary for each new set of bars  124 . 
       FIG. 3  shows a cross sectional view of the filter assembly  100  according to one embodiment of the present invention. The bars  124  are shown coupled to the interior of the screen  102  and the filter members  110 . Although shown as the bars  124  being coupled to the interior of the screen  102 , it should be appreciated that the bars  124  may be adapted to couple to the exterior of the screen  102  or be included as an integral part of the screen  102 , or coupled to the longitudinal supports  120  or the circumferential supports  122 . These longitudinal supports  120  and circumferential supports  122  could be integral with the screen  102 , or on the interior or exterior diameter of the screen  102 , or any combination thereof. The bars  124  are shown extending from a point just after the first end  126 , shown in  FIGS. 1 and 2 , to the second end  128  where the bars  124  are coupled to the cap  117 . The bars  124  may be coupled to the screen  102  by known methods such as welding, screws, bolt, etc. or may simply rest against screen  102 . The bars  124  provide extra stiffness for the screen  102  to resist lateral current and intake loads. Further, although the bars  124  are shown as helical members it, should be appreciated that any non-longitudinal arrangement of bars may be used. 
     The bars  124  are shown, in  FIG. 3 , as being solid cylindrical members, but could just as effectively be tubular or any long member having a polygonal cross-section, an angle iron, a channel, etc. 
       FIG. 4  shows another embodiment of a filter assembly  400 , with the filter members  410  shown only cross-sectionally for clarity, having the same support structure  118  as described above. The filter assembly  400  has only one screen  402  with an inlet pipe  406  coupled to a plate  416 . The plate  416  couples to the screen  402 , which couples to a cap  417 . The inlet pipe  406  as above has an optional flange  408  for attaching the filter assembly to a piping system not shown. The filter assembly  400  has a primary flow modifier  412 , a secondary flow modifier  414 . 
       FIG. 5  shows an alternative embodiment of the filter assembly  500 . The filter assembly  500  is substantially the same as the embodiments above, however, the support structure  518  consists of a series of helical bars  524  which as above follow the screen  502  but do not meet an the plate  516  and the cap  517 . 
     Each of the filter assemblies above is shown, for simplicity as having a primary flow modifier and a secondary flow modifier. It should be appreciated, however, that any number of flow modifiers and any arrangement contemplated in the art may be used for the modifiers. Examples of cylindrical screens with flow modifiers are shown in U.S. Pat. No. 6,051,131 to Maxson, and U.S. Pat. No. 6,712,959 to Ekholm, et al., the disclosures of which is incorporated by reference herein. 
     Further, it is contemplated, in an alternative embodiment, that the support bars  124  run in a non-longitudinal straight line from the plate  116  to the cap  117 . Thus, two or more bars  124 , would attach to the plate  116  and the cap  117  at different longitudinal locations and act as cross-bracing for the screen  102 . 
     While the foregoing is directed to embodiments of the present 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.