Abstract:
An improved fluid level verification apparatus for use on liquid filled containers and configured to reduce inherent mechanical stresses on the inspection tube and resist leakage due to environmental, chemical, thermal or mechanical expansion cycles by using a protective shield member to encase the inspection sight member, and, also, a method for permanently sealing the fluid level detection apparatus.

Description:
BACKGROUND OF 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 a fluid container, 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 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, assigned to the same assignee as the present application, 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 oaring 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 sight monitor, which incorporates grooving and o-rings to isolate the inspection tube from the environment. However, the Jackson invention is relatively 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. Furthermore, this 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, also assigned to the same assignee as the present application, 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 was designed for assembly without the need of o-ring grooves on the exterior or interior portions of the inspection tube. The ends of the inspection tube are restricted and nested in the end members. 
     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 sight tube. Fluid leaks are minimized by placing the glass sight tube in compression with the o-ring seal nested in the respective end member. The glass sight 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 sight tube, adapts poorly to thermal, environmental and chemical expansion cycles and therefore is susceptible to leakage. 
     Lukas, U.S. Pat. No. 3,455,163, describes a liquid level gauge where the apparatus is backwardly attached to the liquid tank. The Lukas Invention allows for the inspection sight member to be fittingly secured within the support body by means of plugs placed at the ends of the inspection sight member. However, the use of plugs to secure the inspection sight member within the apparatus causes compressive stress on the inspection sight member. Furthermore, the Lukas invention is not easily attached or removed from a liquid tank. 
     One advantage of most prior art fluid level detection apparatuses is the ease of replacing the inspection sight member without having to replace the rest of the apparatus. However, the trend in recent years is that users of the apparatus are replacing the entire apparatus, even if only the Inspection sight member needs to be replaced. 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. Therefore, a need exits for a fluid level verification apparatus that is simple to manufacture yet durable and reliable in use. 
     SUMMARY OF INVENTION 
     It is, therefore, 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 and remain assembled through subsequent handling, transport, and shipping operations. 
     Specifically, it is an object of the present invention to provide a fluid level verification apparatus that requires no reassembly before use for a wide range of devices and other objects of interest. 
     Yet another object of the present invention is to protect the transparent inspection tube from mechanical stress during manufacture, transport, handling, shipping, assembly, and use for a wide range of devices and other objects of interest. 
     Another further object of the present invention is to provide a means to reduce or minimize stress on the apparatus, whether such stress is due to thermal, mechanical, environmental or chemical agents acting upon the apparatus. 
     Still another object of the present invention is to provide a means to reduce or minimize leaking of the fluid flowing through the apparatus. 
     Still another further object of the present invention is to provide added support to the inspection sight member without adding unnecessary stress to the inspection sight member. 
     Another further object of the present invention is to reduce or minimize stress to the sight member caused by interconnectivity of the end members, sight member, and the shield member of the apparatus. 
     Still another object of the present invention is to reduce or minimize leaking of the fluid flowing through the apparatus, and doing so with a minimum amount of stress resulting on the sight member. 
     Still another object of the present invention Is to reduce the number of components required for the resulting assembly thereby decreasing manufacturing costs. 
     Another further object of the present invention is to provide a method for permanently connecting the end blocks of the apparatus to the shield member of the apparatus without adding stress to the inspection sight member. 
     Still another object of the present Invention Is to provide an apparatus that may contain a thermometer for measuring the temperature of the fluid flowing through the apparatus” conduit. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is an isometric view of the present invention, as it would appear in the environment; 
     FIG. 2 is an exploded isometric view of the cooperating components of the present invention; 
     FIG. 3 is a detailed isometric view of an end member used in the present invention; 
     FIG. 4 is an isometric fragmentary view detailing the end of the sight tube shield member used in the present invention; 
     FIG. 5 is an exploded isometric fragmentary view of the end member illustrating its relationship with the shield member; 
     FIG. 6 is an isometric fragmentary view of the means used in securing the end members to the shield member; 
     FIG. 7 a  is a fragmentary elevated view of an alternative means used in securing the end members to the shield member; 
     FIG. 7 b  is a fragmentary elevated view of the second step for the alternative means of FIG. 7 a  to connect the end members to the shield member; 
     FIG. 8 is a longitudinal sectional fragmentary view of the present invention taken along lines  8 — 8  of FIG. 1, and showing in detail, an end member secured to the shield member. 
     FIG. 9 a  is a front elevated view of another embodiment of this invention in which the sight member is arranged to receive a thermometer seated within the hollow bore of the sight tube. 
     FIG. 9 b  is a side longitudinal sectional view of the thermometer adaptation of this invention taken along line  9   b    9   b  of FIG. 9 a.    
     FIG. 10 a  is a longitudinal sectional fragmentary view of an alternate embodiment of the present Invention similar to the view of FIG. 8, and showing in detail, an end member prior to being permanently secured to the shield member. 
     FIG. 10 b  is a longitudinal sectional fragmentary view of an alternate embodiment of the present invention similar to the view of FIG. 8, and showing in detail, an end member secured to the shield member. 
    
    
     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 that may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. Like parts, described herein, are designated by like reference numbers. 
     Referring to FIG. 1, there is illustrated an embodiment of an improved fluid level verification apparatus utilizing a transparent tubular inspection sight member  10 . The sight member  10  is encased and supported by a shield member  12 , said shield member  12  having a first end  14  and a second end  16 . Also depicted is a pair of substantially Identical end members, or supporting blocks  18 . Each block  18  has six sides and a mounting bolt  20 . One of the blocks  18  is permanently secured to the shield member  12  at the first end  14 , and the other block  18  is permanently secured to the second end  16 . The means to permanently secure the end blocks  18  to the shield member  12  can be seen by noting the indentations  22  at each end of the shield member  12 , which will later be described. 
     Referring next to FIGS. 2,  3 , and  5 , each end block  18  has an inwardly facing nipple  24  with an outwardly extending nipple extension  26  at the extremity of the nipple  24 . The nipple extension  26  preferably has a smaller circumference than the nipple surface  28 . The nipples  24  taper outwardly from the respective nipple bases  30  at the faces  18   f  of end blocks  18  to the respective nipple surfaces  28 . 
     With particular reference to FIG. 2, the inspection sight member  10 , with its respective ends  32  and  34 , is placed inside of the shield member  12 . The ends  32  and  34  are in contact with resilient o-ring end seals  36 . Each end seal  36 , in turn, is fittingly placed around a respective nipple extension  26  and sealingly engages the respective ends of the sight member  10  to minimize fluid leakage. 
     Referring to FIGS. 1 and 2, the sight member  10  is protected from the environment by the shield member  12 . Ends  14  and  16  of the shield member  12  extend longitudinally beyond ends  32  and  34  of the sight member. Opening  35  in the shield member  12  allows sight member  10  to be visible while still being protected by shield member  12 . 
     Again, with particular reference to FIG. 2, the shield member  12  has a bore  71  longitudinally centered throughout the shield member  12 . The diameter of the bore  71  is slightly larger than the diameter of the sight tube member  10 . The sight tube member  10  is telescopingly placed inside shield member  12 . 
     Still with particular reference to FIGS. 2 and 9 b , the respective mounting bolts  20  comprise a head  38 , a hollow shank  40  (see FIG. 9 b ), an external thread  42  and a cylindrical bore  44  with an inner diameter  46 . Interposed on the shank  40  at a right angle is an intersecting cross hole  48 . The shank  40  terminates in a bolt head  38 . The bolt head  38  has a bolt face  50  and an underside  52 . The underside  52  of the bolt face  50  has an annular groove  54  (see FIG. 9 b ) arranged to receive a conventional o-ring  56 . The diameter of each of the re-entrant bores  58  (see FIG. 9 b ) of the respective blocks  18  is larger than the inner unthreaded portion  43  of the bolts  20  to provide sufficient spacing for free flow of fluid through the hollow bore  44  of the bolt  20 , the bolt holes  48 , the aperture  62  of the nipple  24  and the conduit  64  of the sight tube  10 . The respective sides of the end blocks  18  have an annular groove  65  to receive a resilient o-ring  67  (see FIG. 9 b ). 
     With further reference to FIGS. 2 and 9 b , the sight member  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  20  compresses the sealing gasket  56  (see FIG. 9 b ) against the face  18   b  of the block  18 , thus facilitating a hermetic closure. Similarly, the seal  67  resting on the bolt  20  at the junction of the thread  42  and the shank  40 , is compressed at the annular groove  65  creating a hermetic closure of the seal  67 , the annular groove  65  and the bore  58  of the block  18 . Seal  67  also seals against the tank surface (not shown) to prevent leakage around the thread  42  when the fluid level verification apparatus is mounted to the tank. 
     Fluid dispensed from and returning to the object of interest, such as a tank (not shown but including an entrance threaded opening matching the threads  42  of the bolts  20 ), flows through the bolt  20  by means of the re-entrant bore  44 , and the block  18  by means of the bore  58  in the block  18 , and cooperating with the cross hole  48 . Fluid enters the aperture  62  of the nipple  24 , and fills the conduit  64  of the inspection sight tube member  10  to the liquid level of the tank supporting the sight member  10 . 
     Referring specifically to FIG. 3, each block  18 , preferably includes a plurality of faces,  18   a ,  18   b ,  18   c ,  18   d ,  18   e , and  18   f . A cylindrical nipple extension  26  of said nipple  24  protrudes at a generally perpendicular offset from the face  18   f  of the respective end blocks  18 . The nipple  24  has an aperture  62 , which extends through the nipple  24  and the nipple extension  26  to intersect a bore  58  of the block  18 , and is oriented generally parallel with the axis of the nipple  24 . 
     Still referring particularly to FIG. 3, the nipple  24  is of a predetermined nipple height  66 . The nipple  24  has a nipple base  30 . The circumference of the nipple  24  tapers outward from the nipple base  30  to the nipple surface  28 , with a minimum circumference at the nipple base  30 , to a maximum circumference at the nipple surface  28 . The circumference of the nipple extension  26  is smaller than that of the nipple base  30  or the nipple surface  28 . The aperture  62  concentrically runs through the nipple  24  and the nipple extension  26 , allowing for a free flow of fluid in communication with the bore  58  of the end block  18 . 
     With particular reference to FIG. 4, a fragmented view of the sight tube  10  and the shield member  12  is shown in connection with the shield member end  14 . On the inside of the shield member  12  at said end  14  are concentric grooves  68  and  70 . Concentric groove  68  has a slightly larger diameter than the inner diameter of the bore  71  running through the shield member  12 . The larger diameter of groove  68  results in a thinner section of the shield member  12  at that point, thereby easing the eventual indentation  22  (see FIG. 8) of the shield member end  14 , and will hereinafter be described. 
     In FIG. 5, the end block  18  is shown enroute to placement inside the shield member  12 . Nipple  24  has a diameter  72  essentially the same as the diameter of the bore  71  at the end  14  of the shield member  12 , with just enough difference to allow the nipple  24  to fittingly slide through the shield member bore  71 . Face  18   f  of the end block  18  will abut the top face  74  of the shield member  12 . The nipple extension  26  will nestle into the inner diameter of end seal  36 . The end seal  36  (not shown in FIG. 5) is seated between the sight tube  10  and the nipple  24 . The faces  18   f  and  74  meet in such a way that the nipple height  66  longitudinally extends into the tube shield bore  71  so that the end of the nipple extension  26  may be at the same latitude as that of the end  32  of the sight tube  10 . However, it should be noted that the diameter of nipple extension  26  is small enough not to interfere with the inner diameter of sight member  10 . 
     Referring particularly to FIGS. 6 and 8, a means for permanently securing the block end  18  to the end  14  of the shield member  12  is shown. Conventional tool steel punches  76  are used to indent or stake opposing sides  12   a  and  12   b  of the shield member  12 . The punches  76  will preferably come in at the latitude where groove  68  (see FIG. 8) is located on the shield member  12 . The punches  76  form the indentations  22  in each of the respective sides  12   a  and  12   b  of the shield member  12 , which cause detents  80  at the approximate latitude said groove  68  is located (see FIG.  8 ). It is within the purview of the present invention to incorporate one, two, three or more punches  76  simultaneously or at various intervals during the staking operation. 
     FIG. 7 a  shows means for an alternative method of permanently connecting the end block  18  to the shield member  12 . The block end  18  and the shield member  12  are placed squarely together so that the side  12   b  is flush against a flat surface  78 . The punch  76  forms the indentation  22  on the side  12   a  of the shield member  12  which is opposed to the side  12   b  touching the flat surface  78 . The indention  22  Is at the latitude in the shield member  12  where said groove  68  is located, forming the detent  80  at the approximate latitude said groove  68  is located (see FIG.  8 ). 
     FIG. 7 b  shows the means for continuing the process in FIG. 7 a . The end block  18  and the shield member  12  are rotated 180 degrees. Side  12   a  is now flush against the flat surface  78 . The punch  76  comes In contact with side  12   b  to form an indention  22  at the latitude in the shield member  12  where groove  68  is located, forming the detent  80  at the approximate latitude said groove  68  is located (see FIG.  8 ). 
     FIG. 8 shows a fragmentary cross-sectional view of the fluid level detection apparatus  9  after the end block  18  and the shield member  12  have been connected and secured. The cross-sectional view of the apparatus shows the sight tube member  10  fittingly connected with the end seal, or o-ring  36 . The end seal  36  is shown seated between the sight tube member  10  and surrounding the nipple extension  26 . An unblocked passageway is shown between the hollow bore  58  of the end block  18 , the cross hole  48  of the bolt shank  40 , the aperture  62  through the center of the nipple  24 , and the conduit  64  passing through the sight member  10 . The indention  22  forms a detent  80  at the concentric groove  68 , which securely engages the nipple  24  to hold the end block  18  in place. 
     Next, with particular attention to the views of FIGS. 9 a  and  9   b , it will be observed that the verification apparatus of this invention may also be used in connection with thermometers or other devices requiring protection from the elements. Again, like parts are indicated utilizing like reference characters. 
     The hollow shield member  12  houses a protective tubular sight or sight member  10 . The bore or inner diameter  11  of the sight member  10 , in turn, may house an elongated thermometer  13  held in place by means of longitudinally spaced o-rings  15 . The o-rings  15  are preferably expandable to hold the thermometer  13  in compression against the inner diameter  11  of the tubular sight  10 . The thermometer  13  may be of known construction and comprise an elongated transparent tube housing a heat expandable substance, such as dyed mineral spirits, mercury and/or other equivalent materials  17 . The tubular thermometer  13  is conventionally positioned adjacent a backing temperature indicating plate  19 , including numbered indicia arranged to indicate the temperature of fluid, such as heated water or oil, passing through the conduit  64  of the sight member  10 . 
     As will be noted from the views of FIGS. 9 a  and  9   b , the various cooperating components of the present apparatus embodiment act in similar fashion as the components illustrated and described in connection with the views of FIGS. 1-8, inclusive. The bolts  20  are arranged to be seated In the bores  58  of the respective end blocks  18 , and respectively include re-entrant bores  44 , which intersect aperture  62  of the end blocks  18 . The bolts  20  are appropriately sealed to the end block  18  by means of o-rings  56  seated there between. 
     An alternative construction of the seal between each site member  10 , shield member  12  and end block  18  is shown in FIGS. 10 a  and  10   b.  The configuration of the nipple  24  extending from side  18   f  of end block  18  has been replaced with an annular skirt  90  having a groove  92  formed therein. The counter bore  71  formed in the shield member  12  has been extended inwardly. In contrast to the above-described embodiment, the o-ring  36  is now placed around the smooth outer perimeter of site member  10 . When the outermost surface  94  of the annular skirt  90  of end block  18  is placed into the counter bore  71  of the shield member  12 , the o-ring  36  is slightly compressed forming a hermetic seal between the site member  10 , shield member  12  and end block  18 . In contrast to the above-described embodiment, this arrangement prevents the necessity of putting the site member  10  under any axial compression. It is also desirable to have a press fit between the counter bore  71  of shield member  12  and annular skirt  90  of end block  18 . The press fit aids during assembly in that it is not necessary to retain the shield member  12  and end block  18  under compression during the staking process. As shown in FIG. 10 b,  once the site member  10 , shield member  12  and end block  18  are assembled, a greater variation is allowed for the exact location of the stake on each side of the shield member  12  without compromising the critical seal. 
     The sight tube  10  may be manufactured from glass. However, various substrates such as nylon, polycarbonate, or other synthetic materials may be used. While shown to be cylindrical in shape, it is conceivable that other conduit cross-sectional configurations could be utilized. 
     The shield member  12  and the end blocks  18  may be manufactured from aluminum, or other metals with similar malleable qualities of aluminum. 
     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.