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 by using internal grooves and entrapped o-rings.

Description:
RELATED APPLICATION 
     This application claims the benefit of Provisional Application No. 60/212,931, Filed Jun. 20, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     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. 
     2. Description of the Prior Art 
     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. 
     While the prior art devices have operated with success, they have been unsatisfactory in several respects. 
     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. 
     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 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. 
     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. 
     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. 
     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. 
     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 
     Therefore, it is an object of the present invention to provide an improved fluid level verification apparatus. 
     Another object of the present invention is to provide a fluid level verification apparatus which can be fabricated as a kit and remain assembled through subsequent handling, transport, and shipping operations. 
     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. 
     Another object of the present invention is to protect the transparent inspection tube from mechanical stress during manufacture, transport, handling, shipping, assembly, and use to a wide range of devices and other objects of interest. 
     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. 
     Another object of the present invention is to provide a means to reduce or eliminate leaking of the fluid flowing through the apparatus. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded isometric view of the present invention; 
     FIG. 2 detailed, exploded isometric view of a supporting block of the present invention; 
     FIG. 3 detailed isometric view of a bolt used in the present invention; 
     FIG. 4 is a vertical cross sectional view of the inspection tube of the present invention; 
     FIG. 5 is a cross-sectional view of the present invention; and 
     FIG. 6 is an enlarged fragmentary, cross-sectional view of a cooperating block, bolt and inspection tube of the present invention. 
    
    
     The invention may be embodied in several forms without departing from its spirit or essential characteristics. The scope of the invention is defined in the appended claims, rather than in the specific description preceding them. All embodiments that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced by the claims. 
     DETAILED DESCRIPTION 
     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. 
     Referring to FIG. 1, an improved fluid level verification apparatus  10  of the present invention is shown. The apparatus  10  has a clear inspection tube  11  having a first end  18  and a second end  20 . Also depicted is a pair of end members or supporting blocks  50 , each block  50  having six sides and a pair of mounting bolts  90 . Each block  50  is removably secured to the inspection tube  11  at the first end  18  and second end  20 , respectively. In turn, each bolt  90  is seated in a respective block  50 . 
     Referring specifically to FIG. 2, each block  50 , preferably comprises a plurality of faces  58   a    58   b    58   c    58   d    58   e    58   f,  has a cylindrical projection or nipple  52  protruding at a generally perpendicular offset from a face  58   a  of the block  50 . The nipple  52  has an aperture  82 , which extends through the nipple  52  from the tip  86  to intersect a bore  56  of the block  50 , and is oriented generally parallel with the axis of the nipple  52 . The nipple  52  is of a predetermined nipple height  84 . The nipple  52  has a concentric channel  70  with a predetermined channel depth  72  and channel height  78 . 
     Still referring to FIGS. 1 and 2, a tube seal  30  is depicted. The tube seal  30  fits on the nipple  52  and is seated in the channel  70 . In a preferred embodiment, the tube 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. 
     Referring now to FIGS. 1,  2 ,  5  and  6 , the face  58   b  of block  50  has a depressed annular groove  54 , which locates a concentrically located recessed inwardly tapered bevel  60  and communicating with the coaxial bore  56 . As previously stated, the annular groove  54 , the bevel  60 , and the bore  56  are located on a face  58   b  that is adjacent and generally perpendicular to the nipple  52 . The bore  56  projects through the entire block  50  and intersects the aperture  82  of the nipple  52 . A seal  62  sits on the block  50  at the depressed annular groove  54 , creating a hermetic closure between the seal  62 , the recessed bevel  60 , the bore  56  and a bolt  90 . Again, in the preferred embodiment, the seal  62  may comprise an o-ring or similar structure formed from a deformable material. When assembled, as shown in FIGS. 5 and 6, the bolt  90  is placed through the block  50  and the seal  62  creates an interference fit with a bolt thread  96  and a shaft  102 . 
     With reference to FIG. 3 in particular, the bolt  90  comprises a head  94 , a hollow shaft  102 , a thread  96  and a cylinder  92  with an inner diameter  100 . Interposed on the bolt shaft  102  at a right angle is an intersecting bolt hole  108 . The shaft  102  terminates in a bolt head  94 . The bolt head  94  has a bolt face  112  and an underside  114 . The underside  114  has an annular groove  116  arranged to receive a gasket  98 . The diameter of each of the bores  56  of the respective blocks  50  is larger than the inner unthreaded portion of the bolts  90  to provide sufficient spacing for free flow of fluid through the hollow bore  92  of the bolt  90 , the bolt holes  108 , the aperture  82  of the nipple  52  and the conduit  14 . 
     Now referring to FIG. 4, a vertical cross section of the inspection tube  11  is shown in detail. The tube  11  comprises the first end  18 , the second end  20 , a tube length  12 , a conduit  14 , and an outer diameter  16 . Positioned at a predetermined distance from the respective tube ends  18 ,  20  grooves  22  are oppositely disposed, each having a respective groove height  24  and groove depth  26 . The respective groove depths  26  are selected to accommodate sealing gaskets  30 . 
     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. 
     The inspection tube  11  is removably secured to the nipple  52  by means of the tube seal  30  that fits on the nipple  52  at the channel  70 . The tube seal  30  simultaneously lodges in the groove  22  of the inspection tube  11 . 
     Referring now to FIG. 5, the apparatus  10  is connected in fluid flowing relation to an object of interest, such as a tank (not shown). So connected, the compression exerted on the respective bolts  90  compresses a sealing gasket  98  against the face  58   f  of the block  50 , thus facilitating a hermetic closure. Similarly, the seal  62  resting on the bolt  90  at the junction of the thread  96  and shaft  102 , is compressed at the annular groove  54  creating a hermetic closure of the seal  62 , the recessed bevel  60 , annular groove  54  and bore  56  of the bolt  90 . Seal  62  also seals against the tank surface (not shown) to prevent leakage around thread  96  when the apparatus  10  is mounted to the tank. 
     Fluid dispensed from and returning to the object of interest, such as a tank  5  (not shown but including an entrance threaded opening matching the threads  96  of the bolts  90 ), thereby flowing through the bolt  90  by means of the cylinder bore  92 , and the block  50  by means of the bore  56  in the block  50 , and cooperating with the bolt hole  108 . Fluid enters the aperture  82  of the nipple  52 , and fills the conduit  14  of the inspection tube  11  to the liquid level of the tank supporting the inspection tube  11 . 
     Referring generally to FIG.  4  and of particular importance, the inspection tube  11  has grooves  22  positioned near the first end  18  and second end  20 , respectively. As previously mentioned, each undercut groove  22  of the tube  11  is dimensioned so that the tube seal  30  lodges in the respective groove  22 , creating a hermetic closure when the seal  30  is simultaneously fit on the respective nipple  52  and assembled to the tube  11  to provide the apparatus  10  of the present invention. As opposed to the press fit relationship taught in the prior art, a slip fit exists between the inspection tube  11 , seal  30  and nipple  52 . The seal  30  operates not only to seal the block  50  to the tube  11 , but also to hold each block in place. Based upon of the slip fit relationship between the groove  22 , the o-ring  30  and the channel  70  of the nipple  52 , a hermetic 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. 
     A second important aspect of the invention relates to the formation of the inwardly tapered, recessed bevel  60  and its cooperating coaxial inward tapered bore  56 . As shown in FIG. 6, the recessed bevel has an inner diameter  44  within the concentric bore  56  that is located adjacent the block face  58   b.  The inner diameter  44  is less than the recessed bevel outer diameter  46  located at the innermost portion of the concentric bore  56 . The recessed bevel  60  retains the seal  62  and thus prevents displacement of the seal  62  during shipping. The same benefit is derived during installation of the fluid level verification apparatus  10 . By positively retaining the seal  62  within block  50 , the seal will not become fully or partially dislodged during installation. 
     Also, of particular importance is the above described interference fit between the seal  62  and an outwardly extending flange, which may be in the form of the innermost bolt thread  96 . As best seen in FIG. 6, the major diameter  48  of the bolt threads is greater than the inner diameter  50  of the seal  62 . Once assembled, the resulting interference fit prevents the bolt  90  from becoming dislodged from the block  50  as commonly occurs with prior art devices, particularly during shipping. This apparatus also provides a benefit during installation, as the installer is free to manipulate the apparatus  10  without the bolts  90  falling free from their associated blocks  50 . 
     The above described embodiments of this invention are merely descriptive of its principles and are not to be limited. The scope of this invention instead shall be determined from the scope of the following claims, including their equivalents.