Abstract:
An improved fluid level verification apparatus which may be manufactured or otherwise fabricated as a kit and assembled at a remote location for use on liquid filled containers and configured to reduce inherent mechanical stresses on the inspection tube and resists leakage due to environmental, chemical, thermal, or mechanical, expansion cycles using internal grooves and entrapped o-rings sheathed into multi-faced end blocks in a symmetrical configuration.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates generally to a fluid level verification apparatus which is operable to measure the amount of fluid present in an object of interest, such as a tank, machine, or other article of manufacture, and more specifically, to an apparatus which may be manufactured or otherwise fabricated as a kit and assembled at a remote location for use on particular machines or in manufacturing processes; and which minimizes the number of components required; and further to a fluid level verification apparatus which reduces mechanical, thermal and chemical stresses on the apparatus. 
         [0003]    2. Description of the Prior Art 
         [0004]    The prior art is sated with examples of fluid level verification apparatuses which provide a means for visually verifying or otherwise discovering the fluid levels in an object of interest, such as manufacturing machinery, fluid holding tanks, or other similar assemblies. For example, in certain industrial processes or in certain machines or other articles of manufacture, it is important that particular fluids, such as lubricants, coolants, hydraulic fluids, or other fluid components, be stored in tanks and periodically dispensed from such tanks. Prior art fluid verification devices have typically included a transparent tube or inspection window, which is connected in particular relation to the holding tank, and which provides a quick and convenient means by which an observer may visually verify the level of the fluid present. 
         [0005]    While the prior art devices have operated with success, they have been unsatisfactory in several respects. 
         [0006]    Gruett U.S. Pat. No. 5,323,653 provides a detailed background of the prior art and describes a fluid level verification apparatus that can be fabricated as a kit and assembled at a remote location. Gruett contemplates an inspection tube having an interior conduit dimensioned to create an interference fit with an o-ring used to hermetically seal the inspection tube to an end member. The Gruett apparatus requires a separate seal on the outer diameter of its glass inspection tube to complete a hermetic seal. 
         [0007]    Jackson U.S. Pat. No. 4,345,468 describes a double tube liquid site monitor which incorporates grooving and o-rings to isolate the inspection tube from the environment. However, the Jackson invention is complex and cumbersome, as it requires numerous parts to protect the inspection tube from the stresses caused by the environment. Moreover, the sealing function of the grooves are limited to the insert ends thus requiring the o-rings to rest against the internal and external surfaces of the inspection tubes that have no such grooves and the problem of mechanical stress induced by the assembly of the inspection tubes to mating components is not contemplated. 
         [0008]    Evans U.S. Pat. No. 4,050,305 describes an external shield bracket for a fluid flowmeter. The fluid of interest flows through a precision glass tube. An operator is protected from accidental explosion of the inspection tube due to fluid pressure by a protective transparent cover mounted on a u-shaped channel bracket. The Evans invention uses many parts, but fails to protect the inspection tube from the environment. Said transparent cover and mounting bracket do not form a hermetic closure for the inspection tube contained therein. 
         [0009]    Gruett U.S. Pat. No. 3,886,796 describes a liquid level gauge with a rigid transparent plastic inspection tube with o-rings seated in grooves located in the end members. The Gruett invention induces mechanical stress on the inspection tube because Gruett did not contemplate o-ring grooves on the exterior or interior portions of the inspection tube. Further, because the ends of the inspection tube are restricted and nested in end members, stresses related to thermal, environmental and chemical expansion cycles are exasperated. 
         [0010]    Lyden U.S. Pat. No. 3,540,276 describes a fluid level gauge. The Lyden invention uses an o-ring seal nested in an end member, communicating with the adjacent end of a site tube. Fluid leaks are minimized by placing the glass site tube in compression with the o-ring seal nested in the respective end member. The glass site tube is required because the Lyden invention requires compressive force on the tube. Thus, the design creates inherent mechanical stress and without utilizing the glass site tube adopts poorly to thermal, environmental and chemical expansion cycles and therefore would be susceptible to leakage. 
         [0011]    Wech, U.S. Pat. No. 6,532,815 describes a fluid level verification apparatus. The Wech invention uses an o-ring seal and internal grooves on the respective end member. The plastic site tube is machined to communicate with an end member nipple and aperture, which limits the amount of fluid to flow through the conduit. 
         [0012]    In addition to the foregoing, many of the prior art devices are cumbersome and otherwise complex in their overall design, thereby increasing the cost to manufacture, decreasing the reliability and making them difficult to maintain. Further, the prior art is replete with designs that inadequately address the often conflicting requirements of resisting fluid leaks and protecting the inspection tube from mechanical, environmental, thermal and chemical stresses. 
       SUMMARY OF THE INVENTION 
       [0013]    Therefore, it is an object of the present invention to provide an improved fluid level verification apparatus. 
         [0014]    Another object of the present invention is to provide fluid level verification apparatus which can be fabricated as a kit and remain assembled through subsequent handling, transport, and shipping operations. 
         [0015]    Another object of the present invention is to provide a fluid level verification apparatus which can be manufactured to provide convenient means to efficiently assemble the apparatus at a remote location for use with a wide range of devices and other objects of interest without waste of effort, time or motion expended on reassembly of the apparatus. Specifically, an object of the present invention is to prevent inadvertent dislodging of particular components comprising the invention, such as the bolts in relation to the blocks. 
         [0016]    Another object of the present invention is to protect the transparent inspection tube from mechanical stress during manufacture, transport, handling, shipping, assembly. 
         [0017]    Another object of the present invention is to provide for easy installation of the subject fluid level verification apparatus, to a tank, vessel, container or other object of interest. 
         [0018]    Another object of the present invention is to provide a means to reduce or eliminate stress on the apparatus, whether such stress is due to thermal, mechanical, environmental or chemical agents acting upon the apparatus. 
         [0019]    Another object of the present invention is to provide a means to reduce or eliminate leaking of the fluid flowing through the apparatus. 
         [0020]    Another object of the present invention is to provide a means to substantially increase the flow of liquid through the apparatus. 
         [0021]    These and other objects of the invention will become apparent in the descriptions and drawings that follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is an isometric view of a fluid level verification apparatus according to the present invention. 
           [0023]      FIG. 2  is an exploded isometric view of the fluid level verification apparatus shown in  FIG. 1 . 
           [0024]      FIG. 3  is an exploded isometric view of a supporting block shown in  FIG. 1  according to the present invention. 
           [0025]      FIG. 4  is an isometric view of a bolt shown in  FIG. 1  according to the present invention. 
           [0026]      FIG. 5  is a cross-sectional view of an inspection tube shown in  FIG. 1  according to the present invention. 
           [0027]      FIG. 6  is a cross-sectional view of the fluid level verification apparatus along line  6 - 6  in  FIG. 1 . 
           [0028]      FIG. 7  is a cross-sectional view of the fluid verification apparatus along line  6 - 6  in  FIG. 1 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
         [0030]    Referring to  FIGS. 1 and 2 , an embodiment of an improved fluid level verification apparatus  10  according to the present invention is shown. The apparatus  10  preferably comprises an inspection tube  11 , a pair of end members or supporting blocks  50 , and a pair of mounting bolts  90 . 
         [0031]    The inspection tube  11  is preferably translucent and more preferably clear. The tube  11  has a first end  18 , a second end  20 , and grooves  22  within an outer periphery  28  of the tube  11  positioned ac a predetermined distance from the respective tune ends  18 ,  20 . The grooves  22  may be formed in the outer periphery  28  in the inspection tube  11  in a variety of ways. In the preferred embodiment, the grooves  22  are formed in the tube  11  when the tube is molded. Alternatively, and not by limitation, the grooves  22  may be cut, machined and/or milled into the tube  11 . In the case of a molded tube  11 , indicia  15  may be formed into the tube during the molding process. The indicia may include, but not be limited to, high and/or low level markings, text, gradients, hash marks, etc. In the case of all tubes  11 , once installed between the blocks  50 , the tube  11  may be rotated as needed. The rotation may occur both prior to and after installation of the verification apparatus  10  (see  FIG. 1 , arrow  17 ). This is a benefit of the non-press-fit nature of the junction between each tube end  18 , 20  and end block  50  as will be explained herein. 
         [0032]    Referring to  FIG. 5 , a vertical cross section of the inspection tube  11  is shown in detail. The tube  11  is further shown having a tube length  12 , a conduit  14 , and an outer diameter  16 . The grooves  22  each have a respective groove height  24  and groove depth  26 . The respective groove depths  26  are selected to accommodate a first seal, such as an o-ring,  30 . 
         [0033]    As shown in  FIG. 5 , the o-ring  30  has an o-ring thickness. It is preferable that the groove depth  26  is greater than half the o-ring thickness  32 . 
         [0034]    The tube  11  may be manufactured from various substrates such as nylon, polycarbonate, or other synthetic materials. While shown to be cylindrical in shape, it is conceivable that other conduit cross-sectional configurations could be utilized. 
         [0035]    Referring specifically to  FIG. 3 , each block  50 , preferably comprises a plurality of faces  58   a,    58   b,    58   c ,  58   d,    58   e,    58   f,  a sheathing aperture  52 , and a block bore  56 . The sheathing aperture  52  has a diameter  84  (see  FIG. 6 ) and extends inward from the block face  58   a  a depth  85  (see  FIG. 6 ). The sheathing aperture  52  also preferably has a channel  70  located therein as predetermined distance inward, from the block face  58   a . In the preferred embodiment, the blocks  50  are symmetrical about a vertical plane as shown in the drawings. While this feature simplifies the assembly of the apparatus  10 , non-symmetrical blocks  50  may be utilized as well. 
         [0036]    The block bore  56  has an inner diameter  44  and extends from the block face  58   b  through the block face  58   f  substantially perpendicular to the sheathing aperture  52 . The bore  56  is fluidly connected to the sheathing aperture  52  by a block passageway  54  (see  FIG. 7 ). The bore  56  preferably has a counterbore  60  extending inward from the block faces  58   b,    58   f  and has a counterbore diameter  46 . Additionally or alternatively, the counterbore  60  is beveled, increasing in diameter as it extends inwardly from the block faces  58   b,    58   f.  The bevel in counterbore  60  retains the respective seals in the block bore  56  and prevents seal misalignment (e.g. pinching) during installation as will be discussed infra. 
         [0037]    Referring to  FIG. 6 , the first seal  30  is depicted. The first seal  30  is preferably configured to fit within the channel  70  of the sheathing aperture  52  and one of the grooves  22  of the tube  11 . In a preferred embodiment, the first seal  30 , as well as other seals hereinafter described, may comprise an o-ring made from deformable synthetic material, such as nitrile, fluorocarbon, EPDM, and other similar materials. 
         [0038]    With reference to  FIGS. 4 and 7  in particular, the bolt  90  comprises a head  94 , a bolt shaft  102 , a thread with a major diameter  48  provided on at least a portion of the shaft  102 , a bolt bore  92  with a bolt bore diameter  100  extending coaxially through the bolt shaft  102 , a bolt hole  108  interposed on the bolt shaft  102  substantially perpendicular to and fluidly connected to the bolt bore  92 , and a bolt junction  104  intermediate to the bolt hole  108  and the thread  96 . The shaft  102  terminates in a bolt head  94 . The bolt head  94  has a bolt face  112  and an underside  114 . A second seal  98  is positioned between bolt underside  114  of bolt  90  and counterbore  60  in block face  58   f.  The bolt shaft diameter  110  is preferably smaller than the inner diameter  44  the respective block bore  56  to provide sufficient spacing for free flow of fluid through the bolt bore  92  and the bolt hole  108 . 
         [0039]    Looking to  FIG. 3 , a third seal  62  is shown. The seal  62  is sized and configured to be placed in the counterbore  60  and has an inner diameter  106 . As shown in  FIGS. 6 and 7 , the seal  62  preferably creates hermetic closure between the seal  62 , the bottom of counterbore  60  and a structure (not shown) on which the apparatus  10  is to be secured. In the preferred embodiment, the seal  62  may comprise an o-ring or similar structure formed from a deformable material such as nitrile, fluorocarbon, EPDM, and other similar materials. 
         [0040]    Seals  62  and  98  are retained in beveled counterbores formed on opposite faces  58   b  and  58   f  of blocks  50 . While seals  62  and  98  are the same size in the preferred embodiment, it should be appreciated that they can be different sizes or diameters. 
         [0041]    The assembled apparatus  10  is shown in  FIGS. 6 and 7 . The first end  18  and second end  20  of the tube  11  are received within the sheathing aperture  52  of respective blocks  50  and the bolts  90  are placed through respective block bores  56 . The diameter  84  of the sheathing aperture  52  is narrowly larger than the outer diameter  16  of the inspection tube  11  to provide sufficient spacing for insertion of either ends  18 ,  20  into the sheathing aperture  52 . The depth  85  of the sheathing aperture  52  is preferably deep enough to allow for insertion of the tube  11  into the sheathing aperture  52 . 
         [0042]    The inspection tube  11  is removably secured to the blocks  50  by the first seal  30  that fits within the channel  70  in the sheathing aperture  52  and simultaneously nests or lodges within the groove  22  of the inspection tube  11 . The interface between the first seal  30 , the groove  22 , and the channel  70  creates a liquid-tight seal to prevent leakage. Based upon the slip fit relationship between the groove  22 , the first seal  30 , and the channel  70  of the sheathing aperture  52 , a hermetic seal or closure is formed with minimal or no mechanical stresses resulting on the inspection tube  11 . By greatly decreasing the radial stresses imparted upon the inspection tube  11 , the expected life of the tube  11  is thereby increased. 
         [0043]    Still referring to  FIG. 6 , the apparatus  10  is configured to be connected in fluid communication with an object of interest, such as a tank (not shown) by the bolts  90 . So connected, the compression exerted on the respective bolts  90  compresses the third seal  98  within the counterbore  60  of the block face  58   f  of the block  50 , thus facilitating a hermetic closure. Similarly, the seal  62  resting on the bolt  90  at the bolt junction  104  is compressed within the counterbore  60  of the block face  58   b  creating a hermetic seal or closure between the seal  62 , the counterbore  60  and the tank (not shown). 
         [0044]    Fluid flows between the tank (riot shown) and the tube  11  through the bolt bore  92  and the bolt hole  108  of the bolt  90  and the block bore  56  and the block passageway  54  of the block  50 . Fluid enters and fills the conduit  14  of the inspection tube  11  to the liquid level of the tank supporting the inspection tube  11 . 
         [0045]    Additionally or alternatively, as best shown in  FIG. 7 , the taper of the counterbore  60  in the block faces  58   b,    58   f  is configured to retain the second and third seals  98 , 62  within the counterbore  60  and, thus prevent displacement of the second and third seals  98 , 62  during shipping. The same benefit is derived during installation of the fluid level verification apparatus  10 . By positively retaining the second and third seals  98 , 62  within the counterbore  60  of the block  50 , the second and third seals  98 , 62  will not become fully or partially dislodged during installation. 
         [0046]    Also, as best seen in  FIG. 6 , the major diameter  48  of the bolt threads  6  is greater than the inner diameter  106  of the third seal  62 . Once assembled, the resulting interference fit prevents the bolt  90  from becoming dislodged from the block  50 , particularly during shipping. The relationship between the bolt threads  96  and the third seal  62  allows the installer to manipulate the apparatus  10  without the bolts  90  falling free from their associated blocks  50 . In addition to preventing the loss or separation of parts during shipping and handling, this also prevents the potential pinching of the seal that is likely to occur with a traditional counterbore. As can be readily appreciated, if the seal is not properly positioned within the counterbore, leaking is likely to occur. 
         [0047]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.