Abstract:
An orifice module for a flow switch system has a cylindrical body which is symmetric about a central axis which defines a metering orifice. An axial central hub holds the stem. The hub connects to the cylindrical body by at least three support spokes which forms a plurality of flow channels angularly disposed about the central axis. The module interacts with the flow switch to enhance the function of the flow switch and also reduces turbulence in the fluid flow system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority of U.S. Provisional Patent Application No. 62/310,066 filed on Mar. 18, 2016, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates generally to flow switches for controlling fluid flow. More particularly, this disclosure relates to a flow switch having a pressure responsive member for controlling fluid flow. 
         [0003]    This disclosure has application in conjunction with numerous fluid flow systems which employ a flow switch to generate an electrical signal to control the fluid flow through a conduit. One representative example to which the present disclosure relates is a flow switch of a type such as disclosed in U.S. Pat. No. 5,162,624. The flow switch employs a housing which can be molded from a polyvinyl chloride plastic material or other materials and which defines a flow path between an inlet and an outlet of the housing. The fluid flow system may be employed for various fluids. The housing has an extension which receives a bonnet assembly for mounting a flow switch. The switch assembly carries a magnetic field responsive signal generator such as a reed switch. Electrical leads extend through the body portion of the bonnet assembly. A displaceable shuttle is exposed to the fluid flow. The shuttle and the magnet are displaced by a calibrated flow rate so as to cause a signal generator to change state and transmit a signal from the leads. A bypass path which diverts flow from the main flow path may be opened to control the fluid flow. 
         [0004]    The integrity of any flow switch and the ability of a flow switch to reliably function to control flow over a significant lifetime can be compromised when the flow switch is integrated into a flow passage which has a turbulent flow. An optimum regulatable flow is best realized with a long straight inlet conduit leading to the inlet for fluid exposure to the flow switch. However, space constraints for many installations do not allow for a sufficiently long straight flowpath. 
         [0005]    The flow switch can also be compromised if the shuttle does not properly function concentrically or at a sufficiently precise aligned relationship to the flow path so that it slightly wobbles or engages against the metering orifice. The latter condition may be due to material creep over time or improper installation misalignment. 
         [0006]    The orifice module of the present disclosure is capable of a dual function of reducing adverse consequences of turbulent flow such as may occur adjacent an elbow of a system and also providing a guide or holder for further ensuring that the flow switch assembly is properly concentrically aligned throughout its operation. 
       SUMMARY 
       [0007]    Briefly stated, a flow switch system comprises a generally T-shaped housing having a fluid flow path from an inlet to an outlet and having an extension. A flow switch assembly is mounted in the extension. The flow switch assembly comprises a shuttle displaceable on a stem and is exposed to flow from the inlet toward the outlet. The switch assembly generates an electrical signal in response to fluid flow pressure. An orifice module is disposed in the housing. The orifice module comprises a cylindrical body symmetrical about a central axis defining a metering orifice and mounts an axial central hub. The central hub holds or guides the stem. The hub connects to the cylindrical body by at least three support spokes extending radially from the hub. The support spokes define a plurality of flow channels angularly disposed about the central axis. 
         [0008]    In one embodiment, there are three spokes. The cylindrical body has a collar. The spokes have a generally V-shaped diverter structure. 
         [0009]    A flow module for a flow switch system comprises a generally outer cylindrical sleeve having a central axis. An inner hub forms a cylindrical opening coaxial with the outer sleeve. A plurality of spokes connect the hub and outer sleeve and form a plurality of flow channels angularly disposed about the axis and defined between the segments of the inner hub and the outer sleeve. 
         [0010]    In one embodiment, there are three spokes. The spokes are preferably equiangularly spaced. The outer sleeve is threaded at opposed ends and has a hex surface. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an annotated schematic diagram showing a profile of oil viscosity in a representative long straight pipe with the flow path being sub-divided into concentric laminar sections to illustrate the flow upstream from a representative orifice module and a fluid flow path downstream from the module thereby illustrating the improved laminar flow provided by the orifice module; 
           [0012]      FIG. 2  is an annotated sectional view of a portion of a flow switch system which incorporates the orifice module of  FIG. 1 ; 
           [0013]      FIG. 3  is an end view of the orifice module of  FIG. 2 ; 
           [0014]      FIG. 4  is an annotated sectional view of the orifice module of  FIG. 3  taken along line A-A thereof; 
           [0015]      FIG. 5  is an annotated inflow end view of a second embodiment of an orifice module; and 
           [0016]      FIG. 6  is an annotated side view of the orifice module of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    With reference to the drawings wherein like numerals represent like parts throughout, the principal portion of a representative fuel switch system, for which the orifice module of the present disclosure has particular applicability, is generally designated by the numeral  10  in  FIG. 2 . One preferred embodiment of the module is designated by the numeral  50 . The module  50  is fixedly positioned in a fluid flow passageway adjacent to and in operative proximity to a flow switch assembly  12 . 
         [0018]    With reference to  FIGS. 1-4 , the module  50  comprises a generally cylindrical body  60  symmetric about axis A having a collar  62  at one end thereof. The collar  62  has a shoulder  64  to facilitate mounting. An interior central cylindrical hub  70  is coaxial with the cylindrical body and is axially disposed at the inflow end. The hub  70  is supported at the interior of the cylinder by three equiangularly spaced radial spokes  80 . 
         [0019]    The spokes  80  separate the interior of the cylindrical body into three arcuate shaped axial channels  90 . The channels  90  function to improve the flow through the module, as best illustrated in  FIG. 1 . The spokes  80  may have a wide variety of configurations. The spokes  80  are preferably equiangularly spaced about the central axis. In some embodiments, more than three spokes are provided, although for most applications, it is believed that three spokes provide the optimum structure. The hub  70  defines a concentric guide holder for a stem of the flow switch assembly  12  and has clearance which receives the stem to concentrically secure the stem within the fluid path as described below. In some applications, the hub  70  defines a central flow channel  72 . The opposed end of the body  60  defines a metering orifice  68 . 
         [0020]    With reference to  FIGS. 2-4 , a representative flow switch assembly  12  operatively employs the distributor/guide module  50 . The flow switch assembly  12  is mounted in a T-shaped housing  20  which is preferably manufactured from PVC material. The housing  20  defines an inflow end  22  and an orthogonally positioned outflow end  24 . It will be appreciated that the ends  22  and  24  connect with fluid conduits of various configurations which are not illustrated in the drawings. A third leg defines a receiver  26  for mounting the flow switch assembly. 
         [0021]    The flow switch assembly  12  is mounted by a bonnet assembly  28  and sealed with the receiver  26  of the housing  20 . The flow switch includes a stem  30  which mounts a displaceable shuttle  32  which axially reciprocates in and out of a metering orifice  68  in response to fluid pressure. The stem  30  also mounts an annular magnet  34  which is axially biased by a spring  36  and is carried by the shuttle  32 . The shuttle  32  is thus also axially biased by the spring  36 . A reed switch  40  fixedly positioned on the stem  30  interacts with the displaceable magnet  34  to generate electrical signals which are transmitted via electrical leads  46  extending through the top of the bonnet assembly. The signals typically actuate a stable electrical outlet to operate a pump (not illustrated). 
         [0022]    The module  50  is inserted into the housing and retained in a fixed position against an interior shoulder. The upper inner cylindrical portion of the module interiorly defines the metering orifice  68  of the switch shuttle  32 . The central hub  70  of the module functions as a central holder for receiving the end of the stem  30 . The hub  70  functions to essentially align and hold the stem  30  generally axially (concentrically) to thereby prevent the shuttle  32  from engaging against the sides of the metering orifice. 
         [0023]    In addition, the spokes  80 , which connect the hub  70  to the cylindrical wall of the module, define three metering channels  90 . The distributor flow channels  90  function to distribute the flow which is received in the inflow inlet end  22  of the housing. In the event that, for example, the inlet flow end is disposed adjacent an elbow connection which ordinarily may produce a somewhat turbulent flow, the spokes  80  and distributor channels  90  function to distribute the flow and eliminate a significant portion of the turbulence to provide a substantially uniform laminar flow which impinges the flow switch and in particular the shuttle  32 . The fluid flow characteristics provided by module  30  are illustrated in  FIG. 1 . 
         [0024]    The module  50  may be secured in place by adhesive, fasteners, a threaded engagement, a force fit engagement or other securement means. 
         [0025]    The frontal (upstream) configuration of the spokes may present a V-shaped fluid diverting structure  82  to the fluid, a flat interface with the fluid or other geometric configurations. 
         [0026]    The module  50  may be formed from PVC material, metals, brass, steel and other rigid materials. 
         [0027]    For a fluid switch installation which involves metal, steel or brass fittings, a module  150  may be formed from brass or other metals which are threaded into the housing and fluid conduits, as best illustrated in  FIGS. 5 and 6 . In this embodiment, the opposed exterior ends  152 ,  154  of the module  150  are threaded and an integral hex surface  156  is provided to facilitate the connections into the system. The module connections may employ NTP threads as illustrated, SAE threads or other threaded connections. The ends may also be configured to allow for socket welding or blazing. 
         [0028]    As best illustrated in the end view of  FIG. 6 , the spokes  180  include V-shaped projections  182  to enhance the distribution of the inlet flow which provides three substantially congruent channels  190  around the hub  170  for the inlet flow to the switch. The hub also directs and maintains an existing center smooth axial flow for the fluid. The spokes  180  are preferably equiangularly spaced about the central axis. For this embodiment, the hub  170  may not receive and retain a stem of the flow switch but only function to reduce fluid turbulence. 
         [0029]    It will be appreciated that the module functions to transform a turbulent flow into a more uniform laminar flow such as, for example, may be required without a significant linear pipe upstream from the flow switch. In addition, for some embodiments, the module ensures the concentric position of the stem which may result from creep of the materials over time. 
         [0030]    While preferred embodiments of the foregoing have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.