Abstract:
A strainer has a strainer body with a width and a height. The height of the strainer body is smaller than the width of the strainer body. The strainer body has a serpentine cross-sectional profile to provide rigidity and straining area. A fuel injector includes a strainer as described and a nozzle body with a fuel circuit defined therein. The strainer is integrally coupled to the nozzle body and is in fluid communication with the fuel circuit to remove entrained particulate from fuel traversing the strainer prior to the fuel reaching the fuel circuit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present disclosure relates to fluid systems, and more particularly to strainers for removing particulate entrained in fluid flow through fluid systems. 
         [0003]    2. Description of Related Art 
         [0004]    Aircraft commonly employ fluid systems to provide fluid flows to devices like actuators, heat exchangers, and/or combustors. Since fluid traversing such fluid systems can include entrained particulate material, some fluid systems employ strainers to arrest entrained particulate material. Strainers typically include a straining element with flow orifices sized to prevent entrained particulate from traversing the strainer. Such orifices typically prevent entrained material from being carried into relatively fine features, such as mechanical devices such as valves or slots and holes defined within downstream structures, where the entrained material could otherwise hinder mechanical or fluidic operation. Some strainers have shapes where a portion of the straining element extends along a portion of the fluid flow path, like a top hat shape. Such shapes allow for the straining element to present suitable straining area to fluid traversing the straining element while limiting the pressure drop associated with the strainer. The height of the straining element can influence the packaging of the fluid system components and can necessitate the use of housings with an axial height corresponding to the axial height of the straining element. 
         [0005]    Such conventional strainers, systems incorporating such strainers, and methods of making strainers have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved strainers. The present disclosure provides a solution for this need. 
       SUMMARY OF THE INVENTION 
       [0006]    A strainer has a strainer body defining a flow axis with a width and a height. The height of the strainer body extends in the direction of the flow axis and is smaller than the width of the strainer body. Flow passages extend through the strainer body, and the strainer body has a serpentine cross-sectional profile to provide rigidity and straining area. 
         [0007]    In certain embodiments, the strainer body can define annular corrugations that extend about a flow axis of the strainer body. The corrugations can circumferentially extend about the flow axis at different respective radial offsets relative to the flow axis. One of the corrugations of the strainer body can define the periphery of the strainer body. The strainer body can include a mesh structure, a perforated plate, or layers integrally fused with one another. 
         [0008]    In accordance with certain embodiments, the serpentine cross-sectional profile can span the height of the strainer body. The serpentine cross-sectional profile can span the width of the strainer body. The serpentine cross-sectional profile can span both the width and the height of the strainer body. The serpentine cross-sectional profile can span the entire height and/or the entire width of the strainer body. Flow passages can extend through the corrugations. The flow passages can define respective passage axes that are parallel relative to the flow axis, orthogonal to the flow axis, and/or oblique relative to the flow axis. 
         [0009]    It is also contemplated that, in accordance with certain embodiments, the serpentine cross-sectional profile can include arcuate segments connected by a planar segment. Flow passages can extend through the arcuate segments and the planar segment. Flow passages extending through the arcuate segments can have flow areas and flow area shapes that differ from flow areas and flow area shapes of flow passages extending through the planar segment. Flow passages extending through the arcuate segments can have predetermined flow areas and flow area shapes that are the same in flow passages that extend through the arcuate segments and in flow passages that extend through the planar segment. For example, flow passages extending through the arcuate segments can have flow areas and/or flow area shapes that are identical to flow areas and/or flow shapes of flow passages extending through the planar segment. 
         [0010]    A fuel injector for a gas turbine engine includes a nozzle body, a feed arm coupled to the nozzle body, and a strainer housing with a strainer as described above coupled to the feed arm. The strainer is integral with the strainer housing and is fluid communication with a fluid circuit defined within the feed arm and nozzle body for arresting entrained particulate within fluid traversing the strainer prior to the particulate reaching the fluid circuit. 
         [0011]    These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, embodiments thereof will be described in detail herein below with reference to certain figures, wherein: 
           [0013]      FIG. 1A  is a perspective view of an exemplary embodiment of a strainer constructed in accordance with the present disclosure, showing a strainer body with corrugations; 
           [0014]      FIG. 1B  is a perspective view of an exemplary embodiment of the strainer of  FIG. 1A , showing the strainer in relation to a top hat-shaped strainer; 
           [0015]      FIG. 2  is a cross-sectional side view of the strainer of  FIG. 1A , showing a serpentine cross-sectional profile of the strainer body; 
           [0016]      FIGS. 3A-3C  are schematic views of the strainer of  FIG. 1A  according to embodiments, showing segments of the serpentine cross-sectional profile of the strainer body; and 
           [0017]      FIG. 4  is a schematic view of the strainer of  FIG. 1A , showing the strainer integrally disposed within a strainer housing that is coupled to a fuel injector feed arm. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of a strainer in accordance with the disclosure is shown in  FIG. 1A  and is designated generally by reference character  10 . Other embodiments of strainers and fuel injectors with strainers in accordance with the disclosure, or aspects thereof, are provided in  FIGS. 2-4 , as will be described. The systems and methods described herein can be used fluid systems, such as in fuel injectors for aircraft engines. 
         [0019]    Referring to  FIG. 1A  and  FIG. 1B , a strainer is generally referred to with reference numeral  10 . Strainer  10  includes a strainer body  12 . A flow axis F extends through strainer body  12 . A plurality of corrugations  14  extend about flow axis F. Respective corrugations  14  have radial offsets relative to flow axis F that differ from one another. In the illustrated example strainer body  12  includes five (5) corrugations extending about flow axis F. As will be appreciated by those of skill in the art in view of the present disclosure, strainer body  12  can have fewer than five (5) corrugations  14 , more than five (5) corrugations  14 , as suitable for an intended application. As will also be appreciated, a radially outer corrugation  14  can define a periphery  16  of strainer body  12 . 
         [0020]    Strainer body has a width W and a height H. In the illustrated exemplary embodiment, height H of strainer body  12  is smaller than width W of strainer body  12  such that strainer body  12  is disk-shaped, reducing the footprint of the assembly incorporating strainer  10 . Corrugations  14  provide increased surface area within which flow passages can be defined through strainer body  12 . This allows strainer  10  to present substantially the same flow area and resistance to fluid traversing strainer body  12  as strainer with a larger height, e.g. a top hat-shaped strainer (shown in dashed outline on the right-hand side of  FIG. 1B ). It is contemplated that strainer  10  can have a height H that is about 20% that of a top-hat shaped strainer, reducing the size of a housing  50  (shown in  FIG. 3 ) within which strainer  10  is disposed. Corrugations  14  can also provide rigidity to strainer body  12  such that strainer  10  can resist pressure applied thereto by fluid traversing strainer  10 . As will appreciated by those of skill in the art in view of the present disclosure, in certain embodiments, height H may be greater that width W to provide added straining area and/or to lengthen the interval between strainer replacements in certain applications. 
         [0021]    With reference to  FIG. 2 , strainer body  12  is shown in lateral cross-section. Strainer body  12  includes a serpentine cross-sectional profile  18 . Cross-sectional profile  18  spans height H of strainer body  12 . Cross-sectional profile  18  also spans width W of strainer body  12 . As illustrated, corrugations  14  along both an upper and lower surface of strainer body  12  such that serpentine cross-sectional profile  18  spans the entire height H and width W of strainer body  12 . In the illustrated exemplary embodiment corrugations are disposed on a radial pitch that is uniform, i.e. the corrugation adjacent to the innermost corrugation has a radial offset that is twice that of the innermost corrugation. This is for illustration purposes only and non-limiting. In embodiments, adjacent corrugations  14  may be asymmetrically offset from one another on a pitch that varies across the width of the strainer body. 
         [0022]    Cross-sectional profile  18  includes a plurality of arcuate segments  20  and a plurality of planar segments  22 . One or more of arcuate segments  20  have a convex profile relative to the top of  FIG. 2 , and one or more of arcuate segments  20  have a concave profile relative to the top of  FIG. 2 . Respective planar segments  22  couple adjacent arcuate segments  22  with convex and concave profiles. Planar segments  22  may extend along or be substantially parallel to flow axis F (shown in  FIG. 1 ). 
         [0023]    With reference to  FIG. 3A , a portion of serpentine cross-sectional profile  18  is shown. Flow passages  24  extend through corrugations  14 . Flow passages  24  define passage axes  26  that, based on the location of a respective flow passage  24 , may be parallel with flow axis F, oblique relative to flow axis F, or substantially orthogonal relative to flow axis F. 
         [0024]    With reference to  FIG. 3B , a strainer  100  is shown. Strainer  100  is similar to strainer  10 , and additionally includes a strainer body  112  formed from a mesh structure  102  or a perforated plate  104  that is formed into the illustrated geometry using a piece part operation, such as stamping and/or crimping. As a consequence of the operation(s) used to form strainer body  112 , flow passages extending through strainer body  112  may have shapes and/or flow areas that differ from one another according the influence of the piece-part operation on a given region of strainer body  112 . For example, a flow passage  106  (shown schematically) located on an arcuate segment  112  of serpentine cross-sectional profile  118  may have a flow area and/or shape that differs from that of a flow passage  108  (shown schematically) located on a planar segment  122  of serpentine cross-sectional profile  118 . 
         [0025]    With reference to  FIG. 3C , a strainer  200  is shown. Strainer  200  is similar to strainer  10 , and additionally includes a strainer body  212  formed from a plurality of layers fused to one another in a layer wise manner, such as with an additive manufacturing technique. In this respect strainer  200  includes a first layer  202  fused to a second layer  204 . The layer wise composition of strainer body  212  enables flow passages extending through strainer body  212  to have a predetermined shape and/or flow area irrespective of where a given flow passage is located on strainer body  212 , and decouples the shape of flow passages from piece part operations that could otherwise be used to form a strainer with the illustrated geometry. For example, a flow passage  206  (shown schematically) located on an arcuate segment  212  of serpentine cross-sectional profile  218  may have the same flow area and/or shape as a flow passage  208  (shown schematically) located on a planar segment  222  of serpentine cross-sectional profile  218 . 
         [0026]    With reference to  FIG. 4 , a fuel injector  400  for a gas turbine engine is shown. Fuel injector  400  includes a nozzle body  402  coupled to a feed arm  404 . A strainer housing  406  is coupled to feed arm  404 . Nozzle body  402  has defined within its interior a fuel circuit  408 . Fuel circuit  408  is in fluid communication with a fuel conduit  410  disposed within feed arm  404 . A strainer  10  is disposed within strainer housing  406  and is in fluid communication with fuel circuit  408  of nozzle body  402  through fuel conduit  410 . Strainer housing  406  and strainer  10  are integral with one another, both strainer housing  406  and strainer  10  sharing a first layer  412  fused to a second layer  414  to form an integral (i.e. unitary) structure that is in turn removable fixed to the feed arm  404 . This allows for replacing strainer  10  and strainer housing  406  as a unit without disturbing the arrangement of nozzle body  402  in relation to a gas turbine engine. 
         [0027]    The methods and systems of the present disclosure, as described above and shown in the drawings, provide for strainers with superior properties including reduced height for a given strainer width and effective straining area when compared with traditional strainers. While the apparatus and methods of the subject disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.