Patent Publication Number: US-2010108595-A1

Title: Strainer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from U.S. Provisional Patent Application No. 61/111,909, filed Nov. 6, 2008, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a strainer. More specifically, the present invention relates to a straight strainer assembly having a strainer basket and an elliptical retainer ring for the basket that includes perforations matching the perforations in the strainer basket, such that liquid flowing through the strainer assembly may be strained by both the basket and the retainer ring. 
     2. Description of Related Art 
     Conventional straight strainer assemblies include a first, straight tubular body and a second tubular body attached to the first tubular body and branching therefrom at an angle, typically 45°. Such conventional strainer assemblies require that two T-shaped sections of conduit be cut through with a template and then re-assembled by welding to create a 45° lateral conduit. The lateral conduit is then assembled into a straight strainer by the addition of a flange at the end of the branched tubular body with a blind flange having a round retainer ring welded to its inside. The round retainer ring is designed to hold the round perforated or mesh basket, which is also held at the opposite, straight end by a retainer ring. 
     Such conventional strainer assemblies have suffered from several drawbacks. First, manufacture of the assembly requires the cannibalization of two T-shaped sections of conduit, which leads to material waste, significant assembly time, and increased manufacturing costs. Further, the welded connection between the welded components creates a structural weakness in the assembly, leading to increased weight and a reduced operational lifespan. Finally, the retainer ring does not participate in the straining function of the assembly, thus reducing the flow rate of liquid flowing through the assembly. 
     SUMMARY OF THE INVENTION 
     Accordingly, there is a general need in the art for a straight strainer assembly that reduces material and manufacturing costs, has increased strength, lighter weight and operational lifespan, and also provides a larger flow area as compared to conventional assemblies. 
     According to a preferred non-limiting embodiment of the present invention, a straight strainer assembly is provided. The straight strainer assembly includes a first tubular body extending along a first longitudinal axis between a first open end and a second open end, the first tubular body having a first sidewall defining a first hollow internal cavity; a second tubular body integrally formed with or attached to the first tubular body between the first and second ends of the first tubular body, the second tubular body extending along a second longitudinal axis that is not parallel with the first longitudinal axis, the second tubular body extending between a first open end at least partially joined to the sidewall of the first tubular body and a second open end, and the second tubular body having a second sidewall defining a second hollow internal cavity in communication with the first hollow internal cavity of the first tubular body; a cylindrical strainer basket extending at least partially through the second hollow internal cavity from the second end of the second tubular body into the first hollow internal cavity; and a retainer ring disposed within the first tubular body and having an elliptical face portion extending obliquely within the first tubular body. 
     In a further preferred and non-limiting embodiment, the retainer ring includes a sidewall portion that extends transversely from the elliptical face portion for at least partially engaging a first end of the cylindrical strainer basket within the first tubular body to maintain a position of the cylindrical strainer basket. The second longitudinal axis forms an angle of less than about 90°, and in one preferred and non-limiting embodiment, an angle of about 45° with the first longitudinal axis. 
     In a further preferred and non-limiting embodiment, the second tubular body includes a flange disposed on the second end thereof, and the assembly further includes a blind flange secured to the flange of the second tubular body to close the second hollow internal cavity at the second end of the second tubular body; and a gasket disposed between the flange on the second tubular body and the blind flange for sealing an engagement between the second tubular body and the blind flange. The cylindrical strainer basket may be formed from a screen having perforations and arranged in a tubular configuration. The elliptical face portion of the retainer ring can have perforations corresponding in size to the perforations in the screen of the cylindrical strainer basket. The elliptical face portion of the retainer ring at least partially engages an inner perimeter of the first sidewall. 
     In another preferred and non-limiting embodiment, the assembly further includes a cap retainer disposed within the second tubular body at the second end thereof and engaging a second end of the cylindrical strainer basket to maintain the position of the cylindrical strainer basket. Both the cylindrical strainer basket and the elliptical face portion of the retainer ring strain liquid flowing through the strainer assembly. 
     According to a further preferred and non-limiting embodiment of the present invention, a retainer ring for maintaining a position of a strainer basket in a straight strainer is provided. The retainer ring includes an elliptical face portion adapted to extend obliquely within the straight strainer to engage an inner perimeter of the straight strainer. In another preferred and non-limiting embodiment, the retainer ring extends includes a sidewall portion that extends transversely from the elliptical face portion and is adapted to engage the strainer basket within a straight strainer to maintain a position of the cylindrical strainer basket. The elliptical face portion includes perforations adapted to strain liquid flowing through the straight strainer. 
     These and other features and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a strainer assembly according to an embodiment of the present invention. 
         FIG. 2  is a left side view of the strainer assembly of  FIG. 1 . 
         FIG. 3  is a bottom view of the strainer assembly of  FIG. 1 . 
         FIG. 4  is a cross-sectional side view of the strainer assembly according to line A-A shown in  FIG. 3 . 
         FIG. 5  is a bottom perspective view of a retainer ring of the strainer assembly according to an embodiment of the present invention. 
         FIG. 6  is a top plan view of the retainer ring of  FIG. 5 . 
         FIG. 7  is a cross-sectional side view of the retainer ring according to line B-B shown in  FIG. 6 . 
         FIG. 8  is a perspective view of a strainer basket of the strainer assembly. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     For purposes of the description hereinafter, the terms “end”, “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal” and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting. Further, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. 
     Referring to  FIGS. 1-4 , a strainer assembly  10  according to one preferred and non-limiting embodiment of the present invention is depicted. As shown, the strainer assembly  10  includes a first tubular body  11  extending along a first longitudinal axis L 1  between a first open end  12  and a second open end  13 . The first tubular body  11  includes a first annular sidewall  14  defining a first hollow internal cavity  15  within the first tubular body  11 . A second tubular body  16  is integrally formed with or otherwise attached to the first tubular body  11  between the first  12  and second  13  open ends of the first tubular body  11 . The second tubular body  16  extends along a second longitudinal axis L 2  that is not parallel to, i.e. divergent from, the first longitudinal axis. The longitudinal axis L 2  forms an angle A with the first longitudinal axis L 1 . As shown, the angle A is about 45°, although it is to be appreciated that the angle A between the respective longitudinal axes L 1 , L 2  may be any suitable angle less than about 90°. For example, the angle A may be preferably in the range of about 10° to about 80°, more preferably in the range of about 30° to about 60°, and more preferably in the range of about 40° to about 50°. 
     The second tubular body  16  extends between a first open end  17  at least partially joined to the first sidewall  14  of the first tubular body  11  and a second open end  18 . The second tubular body  16  includes a second annular sidewall  19  defining a second hollow internal cavity  20  within the second tubular body  16 . As shown in  FIG. 4 , the second hollow internal cavity  20  is in communication with the first hollow internal cavity  15  through the first open end  17  of the second tubular body  16  and the first sidewall  14  of the first tubular body  11 . The second tubular body  16  further includes an annular flange  21  disposed on the second end  18  of the second tubular body  16 . 
     It is to be appreciated that the first  11  and second  16  tubular bodies may be formed from a variety of materials, including steel, brass, aluminum and stainless steel. The first  12  and second  13  open ends of the first tubular body  11  and the second open end  18  may also be belled in order to simplify fitting and welding with other tubular conduits. Further, the first  11  and second  16  tubular bodies may be formed from two opposing stamped metal halves that are subsequently secured by a longitudinal butt weld for increased strength. The annular flange  21  at the second end  18  of the second tubular body  16  may be formed from aluminum and separately welded to the second tubular body  16  after the two opposing stamped metal halves have been assembled to form the first  11  and second  16  tubular bodies. 
     With reference to  FIGS. 2 ,  4 , and  8 , the strainer assembly  10  includes a cylindrical strainer basket  25  disposed within the second hollow internal cavity  20  of the second tubular body  16 . As shown in  FIG. 4 , the basket  25  extends from the second end  18  of the second tubular body  16  into the first hollow cavity  15  of the first tubular body  11 . As shown in  FIG. 8 , the cylindrical strainer basket  25  is formed from a length of screen material  26  arranged in a tubular configuration and having a plurality of perforations  27  to allow liquid to flow through the screen material  26  while trapping debris within the basket  25 . It is to be appreciated that the cylindrical strainer basket  25  may be formed from a variety of materials, including brass and stainless steel, and may be arranged in many configurations known to be suitable to those of ordinary skill in the art. 
     With reference to FIGS.  2  and  4 - 7 , the strainer assembly  10  includes a retainer ring  30  disposed within the first internal hollow cavity  15  of the first tubular body  11  for maintaining the position of the cylindrical strainer basket  25  within the first tubular body  11 . The retainer ring  30  has an elliptical face portion  31  that extends obliquely within the first internal hollow cavity  15  of the first tubular body  11 , to engage an inner perimeter of the first sidewall  14 , such that liquid cannot flow between the retainer ring  30  and the first sidewall  14 . As shown in  FIGS. 6 and 7 , the elliptical face portion  31  of the retainer ring  30  has a plurality of perforations  33  formed therein, which correspond in size to the perforations  27  in the cylindrical strainer basket  25 . Thus, the retainer ring  30  may also serve to strain the liquid flowing through the strainer assembly  10  in addition to the cylindrical strainer basket  25 . By utilizing a retainer ring  30  with perforations  33 , the present invention provides an increased flow area and provides 10-15% increase in flow, as compared to a stamped, straight strainer having a non-perforated retainer ring. The retainer ring  30  further includes a cylindrical sidewall portion  32  that extends transversely from a side of the elliptical face portion  31  of the retainer ring  30 . The cylindrical sidewall portion  32  is fitted within and engages a first end of the cylindrical strainer basket  25 , to maintain the position of the cylindrical strainer basket within the first internal hollow cavity  15  of the first tubular body  11 . 
     It is to be appreciated that the retainer ring  30  may be formed from a variety of materials, including stainless steel, aluminum and brass, known to be suitable by those of ordinary skill in the art and may be sealingly engaged with the inner perimeter of the first sidewall  14  according to a variety of techniques, including welding, also known to be suitable by those of ordinary skill in the art. The perforations  33  in the elliptical face portion  31  of the retainer ring  30  match the size of the perforations  27  in the cylindrical strainer basket  25 , and may be formed by a variety of techniques, including laser cutting and/or water jet cutting. Additionally, perforations  33  may also be formed in the cylindrical sidewall  32  of the retainer ring  30 . 
     With reference to  FIG. 4 , the strainer assembly  10  further includes a cap retainer  35  disposed within the second hollow internal cavity  20  of the second tubular body  16  at the second end  18  of the second tubular body  16 . The cap retainer  35  includes a cylindrical sidewall that is fitted within and engages a second end of the cylindrical strainer basket  25  in like manner to the cylindrical sidewall portion  32  of the retainer ring  30 , to retain the second end of the cylindrical strainer basket  25  within the second hollow internal cavity  20  of the second tubular body  16 . 
     With reference to  FIGS. 1-4 , the strainer assembly  10  also includes a blind flange  40  disposed on the second end  18  of the second tubular body  16  that is secured to the annular flange  21  of the second tubular body  16  by an attachment arrangement, such as a plurality of nuts  46  and bolts  47 , to close the second hollow internal cavity  20  at the second end  18  of the second tubular body  16 . A sealing gasket  45  is disposed between the blind flange  40  and the annular flange  21 , to seal the engagement between the blind flange  40  and the annular flange  21  of the second tubular body  16  and in order to prevent leakage of liquid flowing through the strainer assembly  10 . Additionally, the cap retainer  35  may be welded to the blind flange  40 , to position the cap retainer  35  within the second tubular body  16 . 
     With reference to  FIGS. 1-4 , during operation, the strainer assembly  10  will be connected along a conduit for transferring liquids. For instance, the strainer assembly  10  may be used in a line dispensing liquid fuels from a fuel truck to a vehicle, such as an aircraft or work vehicle. Liquid pumped through the conduit flows into the strainer assembly  10  and into the first hollow internal cavity  15  via the first open end  12  of the first tubular body  11 . As liquid flows through the first tubular body  11 , the liquid will pass upward towards the second hollow internal cavity  20  of the second tubular body  16  and into the cylindrical strainer basket  25 . As the liquid passes through the perforations  27  in the screen material  26  of the basket  25 , debris and other contaminants will be removed from the liquid by the basket  25 . Additionally, liquid may flow through the perforations  33  in the elliptical face portion  31  of the retainer ring  30 , which will also remove debris and other contaminants from the liquid. Thus, according to an embodiment of the present invention, both the cylindrical strainer basket  25  and the elliptical face portion  31  of the retainer ring  30  strain liquid flow through the strainer assembly  10 . After passing through the strainer basket  25  and/or the elliptical face portion  31 , the liquid returns to the first hollow internal cavity  15  and exits the strainer assembly  10  via the second open end  13  of the first tubular body  11 . 
     Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.