Abstract:
A level gauge for determining the level of a liquid in a vessel includes lenticular lens assembly allowing a plurality of level indicator flags enclosed therein to be viewed from a wide angle. The indicator flags have an elongated body manufactured from a sheet of material, and form a central pocket for retaining a magnet, and pins on either end for mounting within a frame. A mounting frame positions the lens assembly whereby an open channel is formed between the lens assembly and a back plate. The mounting frame is mounted to the vessel using spacers forming an open gap between the mounting frame and vessel. The open channel and gap minimize the transfer of heat from the vessel to the level gauge. The passage of a float with a magnet on the liquid in the vessel rotates the flags.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/947,901, filed Mar. 4, 2014, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    A magnetic level gauge consists of a pressure tight chamber containing a float with a magnet inside. A visual indicator assembly is attached to the outside of the chamber, consisting of a series of flags or flippers rotatable 180 degrees. Each flipper contains a magnet which interacts with the float magnet to rotate 180 degrees as the float moves past the flipper in the chamber. The flipper rotates in one direction as the float moves past the flipper in a vertical direction, and back to its original position as the float moves in the opposite direction. The flippers each have contrasting colors on opposite sides, so they create a solid visual bar of color, one color below the current location of the float and the other color above the current location of the float. 
         [0003]    The chamber is connected to a liquid process. The float has sufficient buoyancy to ride on the surface of the liquid as it moves up and down. The interaction between the float magnet and the flipper magnets, rotating the flippers as the float moves past as previously described, allows an external visual indication of the level of process liquid inside the chamber without exposing that liquid to the outside atmosphere or requiring direct visual sight of the process liquid. 
       SUMMARY 
       [0004]    A level gauge for determining the level of a liquid in a vessel fluidly connected to a process chamber includes a lens assembly with a lenticular lens for viewing the indicator flags enclosed therein from a wide viewing angle. The position of the flags within the lens, in conjunction with the location and orientation of the lenticular lens allows the flags to be viewed at an angle between directly in front to about 110 degrees on either side of the face of the lens. 
         [0005]    The indicator flags are formed from a monolithic piece of material. The indicator flags extend from a first end to a second end, and form a central pocket for retaining a magnet that rotates within a frame as a float with a magnet riding on the surface of the liquid in the vessel passes behind the frame. The central pocket is formed from the body of the flag and includes a central crescent-shaped member and adjacent upper and lower crescent-shaped members. Tabs formed from the upper and lower crescent-shaped members are bent over the open ends of the pocket to retain the magnet therein. The flag first end and second end form pivot pins that are received within through openings in the indicator flag frame. 
         [0006]    The lens assembly is mounted in a frame that is mounted to the vessel. The frame forms left and right channel members extending from a back plate, wherein the channel members form opposing grooves for positioning the lens assembly whereby a channel separates the lens assembly from the back plate. The back plate is separated from the vessel by spacers forming a gap therebetween. The channel separating the back plate from the lens assembly, and the back plate from the vessel allow air to circulate between the elements avoiding unnecessary heat gain that could affect performance of the components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The drawings constitute a part of this specification and include exemplary embodiments of the disclosed subject matter and illustrate various objects and features thereof. 
           [0008]      FIG. 1  is an elevation view of a visual indicator assembly embodying principles of the disclosed subject matter. 
           [0009]      FIG. 2  is a cross sectional view of the visual indicator assembly of  FIG. 1 . 
           [0010]      FIG. 3  is a perspective cross sectional view of the indicator assembly of  FIG. 1 . 
           [0011]      FIG. 4  is a top plan cross sectional view of the indicator assembly of  FIG. 3 . 
           [0012]      FIG. 5  is a top plan cross sectional view of the lens assembly. 
           [0013]      FIG. 6 . is a perspective view of a flag. 
           [0014]      FIG. 7  is a plan view of the flag. 
           [0015]      FIG. 8  is an elevation view of a flag. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    As required, detailed aspects of the disclosed subject matter are disclosed herein; however, it is to be understood that the disclosed aspects are merely exemplary of the disclosed subject matter, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the disclosed technology in virtually any appropriately detailed structure. 
         [0017]    Certain terminology will be used in the following description, and are shown in the drawings, and will not be limiting. For example, up, down, front, back, right and left refer to the disclosed subject matter as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning. 
         [0018]    Referring to the drawings,  FIGS. 1-8  show a magnetic level gage visual indicator assembly  100  with a wide viewing angle lens assembly  200  embodying principles of the disclosed subject matter. Various aspects and features of the disclosed subject matter include advantages, and provide technical benefits, that are an improvement over current devices. The visual indicator assembly  100  is used with a magnetic float  136  disposed within a vessel  134  connected to a process chamber  144  containing a fluid  142  for measuring the level of the fluid  142  in the process chamber  144 . 
         [0019]    Referring to  FIG. 1 , the vessel  134  is generally installed upright, and is in fluid communication with the process chamber  144 , accordingly, the level of the fluid  142  in the vessel  134  corresponds to the level of the fluid  142  in the process chamber  144 . The magnetic float  136  includes a strong magnet  140  within a housing  138  that is partially submerged in the fluid  142  within the vessel  134 . The float  136  moves up and down with the level of the fluid  142  within the vessel  134  in conjunction with the level of the fluid  142  within the process chamber  144 . The vessel  134  is nonmagnetic allowing the float  136  to freely move within the vessel  134  along with the fluid  142 . The visual indicator assembly  100  is attached to the vessel  134  and represents the level of the fluid  142  in the vessel  134  by the position of indicator flags  170  within a flag assembly  150 . 
         [0020]    The visual indicator assembly  100  includes a flag assembly  150  viewable with a lens assembly  200 . The flag assembly  150  is disposed within the lens assembly  200 , and the lens assembly  200  is connected to a frame  116  mounted to the vessel  134 . 
         [0021]    Referring to  FIGS. 3-4 , the flag assembly  150  includes a frame  152  with a plurality of rotatable flags  170 . The frame  152  is an elongated rectangular member extending between a top end and a bottom end, forming a rear portion  154  between opposing left and right sides  160 ,  164 . The left and right sides  160 ,  164  include a series of opposing through openings or apertures  166  for receiving pins  176 ,  180 , respectively of the flags  170 . The left side  160  forms a stop  162  between the apertures  177  and the rear portion  154  limiting rotation of the flags  170 . 
         [0022]    Referring to  FIGS. 6-8 , each flag  170  includes a generally planar elongated body  172  extending between a first end  174  and a second end  178  along a central axis  194 , and between opposing first and second edges  196 ,  198  on either side of the central axis  194 . The first end  174  forms a first pin  176  from the body  172 , and the second end  178  forms a second pin  180  from the body  172 . In an embodiment, the pins  176 ,  178  are formed by rolling tabs formed at the ends of the body  172  about a central axis  194  extending the length of the body  172  between the first end  174  and second end  178 . The first end  174  also includes a notch  175  formed between the first edge  196  and first pin  176 . The body  172  presents a first face  182  extending between the first and second ends  174 ,  178 , and first and second edges  196 ,  198 , and an opposite second face  184  extending between the first and second ends  174 ,  178 , and first and second edges  196 ,  198 . The body  172  forms a central pocket  186  about a midline  190  extending between the first and second edges  196 ,  198  located between the first and second  174 ,  178  ends. In an embodiment, the pocket  186  is a tubular cavity extending along the midline  190  between the first and second edges  196 ,  198 , and forms an interior wall  302  with an upper and lower crescent-shaped portion  304 ,  306  extending from the first face  182 , and a middle crescent-shaped portion  308  disposed between the upper and lower portion extending from the second face  184 . A first tab  188  at the upper portion is formed at the first edge  196  by removing a portion of the body  172  on either side of the midline  190 , and a second tab  189  at the lower portion is formed at the second edge  198  by removing a portion of the body  172  on either side of the midline  190 . A magnet  192  is disposed within the pocket  186  and secured therein by bending tabs  188 ,  189  toward the adjacent open end of the pocket  186 . The flag  170  is manufactured from a nonmetallic material, including aluminum. In an embodiment, the first face  182  is colored red, and the second face  184  is colored white. The magnet  192  interacts with magnet  140  causing the flags  170  to rotate up and down in the frame  152  as the float  136  moves behind. 
         [0023]    Referring to  FIGS. 3-5 , the lens assembly  200  has an elongated hollow tubular body  202  extending longitudinally between a top end and a bottom end, and extending laterally between a left side  208  and a right side  212  allowing a user to see the flags  170  therein. In an embodiment, the lens assembly  200  is manufactured from clear polycarbonate. In an embodiment, the lens assembly  200  is formed by extrusion. The body  202  forms a rear wall  216  and opposing front face  218  separated by opposing left and right walls  222 ,  224 . A tab  210  extends laterally outward from the left side  208 , and a tab  214  extends laterally outward from the right side  212  allowing the lens assembly  200  to be mounted within a frame  116 . A centerline  233  extends perpendicular through the center of the rear wall  216  and front face  218 . 
         [0024]    The front face  218  includes lens elements forward of the tabs  210 ,  214 . A left wall  222  extends laterally inward from the left end  208  toward the centerline  233  terminating at a left sidewall  223 , and a right wall  224  extends laterally inward from the right end  212  toward the centerline  233  terminating at a right sidewall  225 . The left sidewall  223  extends away from the rear wall  216  terminating at a left lateral  234 , and the right sidewall  225  extends away from the rear wall  216  terminating at a right lateral  236 . The left and right laterals  234 ,  236  extend forward from the rear wall  216 , and inward toward opposite sides of a center pane  232 . The center pane  232  is bisected by the centerline  233  centered between the left and right ends  208 ,  212 , and presents an outer face extending laterally between the left lateral  234  and right lateral  236 . The left lateral  234  extends rearward from the center pane  232  terminating at the left sidewall  223  at an angle of approximately 20 degrees with respect to the outer face of the center pane  232 , and the right lateral  236  extends rearward from the center pane  232  terminating at the right sidewall  225  at an angle of approximately 20 degrees with respect to the outer face of the center pane  232 . The laterals  234 ,  236  have an exterior surface  228 , and an interior surface  230 . The exterior surface  228  presents a planar surface. The interior surface  230  forms a plurality of columns of convex lenses, cells, or lenticules extending between the top end and the bottom end, wherein each lateral  234 ,  236  forms a lenticular lens  238  allowing the flags  170  to be viewed from the left and right side of the assembly  100  by a user at an angle between about 0 degrees to about 110 degrees laterally from the centerline  233 . 
         [0025]    In an embodiment, the pitch, or width of each lenticular cell is about 0.06 inches. 
         [0026]    The flag assembly  150  is positioned within the lens assembly  200 , whereby the rear portion  154  is adjacent the rear wall  216 , the left side  160  is adjacent the left side  208 , the right side  164  is adjacent the right side  212 , the left side  160  is positioned behind the left wall  222 , the right side  164  is positioned behind the right wall  224 , and the flags  170  are visible through the front face  218 . 
         [0027]    The frame  116  extends longitudinally between a top end and a bottom end, and forms a back plate  120  with opposing left and right channel members  118 ,  119 . The channel members include an inwardly open groove  121  running between the top end and bottom end. The left channel member  118  groove  121  receives tab  210 , and the right channel member  119  groove  121  receives tab  214 . 
         [0028]    In use, the flags  170  freely rotate about their pins  176 ,  180  within the frame  152  as the float  136  with the magnet  140  travels up and down within the vessel  134  behind the flag assembly  150 . The flags  170  rotate between a first position with the first face  182  visible through the front face  218 , and a second position with the second face  184  visible through the front face  218 . When a flag  170  is in the first position, the notch  175  is facing upward, and the first end  174  overlaps the stop  162  preventing the first edge  196  from moving forward, away from the rear portion  154 . As the float  136  travels downward in the vessel  134  the magnet  140  interacts with the magnet  192  in each flag  170 , rotating the flags  170  about the pins  176 ,  180  moving the second edge  198  upward and the first edge  196  downward exposing second face  184 . When the flag  170  is in the second position, the notch  175  is facing downward, and the first end  174  overlaps the stop  162  preventing the second edge  198  from moving rearward toward the rear portion  154 . A faceplate  132  adjacent the lens assembly  200  includes graduated markings indicating the level of fluid  142  within the process chamber  144 . As the float  136  travels upward in the vessel  134  the magnet  140  interacts with the magnet  192  in each flag  170  rotating the flags  170  from the second position to the first position. Accordingly, the flags  170  below the location of the float  136  are one color, and the flags  170  above the location of the float  136  are another color providing a visual indication to a user of the level of fluid  142  in the process chamber  144  without exposing the fluid  142  to the outside atmosphere or requiring direct visual sight of the fluid  142  in the process chamber  144 . 
         [0029]    The frame  116  extends longitudinally between a top end and a bottom end, and forms a back plate  120  with opposing left and right channel members  118 ,  119 . The channel members include a groove  121  running between the top end and bottom end. The left channel member  118  groove  121  receives tab  210 , and the right channel member  119  groove  121  receives tab  214 . 
         [0030]    High temperature fluids  142 , such as liquids used in boiler feed water heater systems, can affect the performance and accuracy of float operated fluid level gauges. The assembly  100  includes features that allow the device to operate in high temperature applications. The channel members  118 ,  119  position the lens assembly  200  whereby the back wall  216  is spaced apart from the back plate  120  forming a channel  124  allowing air to pass in between, thereby minimizing heat transfer from the fluid  142  to the lens assembly  200  and flag assembly  150 . The back plate  120  is set off from the vessel  134  by spacers  126  forming a gap  128 . The gap  128  further isolates the lens assembly  200  and flag assembly  150  from the fluid  142 , and distances the frame from the fluid  142 . In an embodiment, the spacers  126  do not transfer heat between the vessel  134  and the visual indicator assembly  100 . In an embodiment, the spacers  126  are ceramic pocket washers. The frame  116  is secured to the vessel  134  by fasteners  130 , including straps. In an embodiment, the fasteners  130  are manufactured from stainless steel, a poor conductor of heat, thereby minimizing the amount of heat transferred to the indicator assembly  100 . 
         [0031]    Various features of the lens assembly  200  and flags  170  provide enhanced visibility of the level indication. The lens assembly  200  is mounted in the frame  116  whereby the face of each flag  170  projects outward beyond the face of the left channel member  118  and right channel member  119  ( FIG. 4 ). The projection of the flags  170  combined with the projection of the front lens  220  beyond the face of the channel members  118 ,  119  allow the flags  170  to be viewed from the side of the visual indicator assembly  100 , thereby allowing an observer to determine the level of the fluid  142  in the process chamber  144  from a wide variety of viewing angles. In addition, the use of lenticular lenses in the left and right laterals  234 ,  236  allow the fluid level to be viewed from a full 220 degree angle. 
         [0032]    It will be appreciated that the visual indicator assembly  100  can be used for various other applications. Moreover, the visual indicator assembly  100  can be fabricated in various sizes and from a wide range of suitable materials, using various manufacturing and fabrication techniques. 
         [0033]    It is to be understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects.