Abstract:
The limitor includes a tubular valve body that houses a poppet valve axially moveable between opened and closed positions by an external float. The poppet is protected from direct engagement with incoming pressurized liquid by an overhead deflector that diverts incoming liquid radially outwardly into an annular region around the deflector so that the liquid can pass through a port underlying and spaced below the poppet. This prevents premature closing of the valve. Preferably, the limitor is constructed from a main support tube that becomes attached to the tank and a valve subassembly that is threadably joined with the tube and projects down into the interior of the tank during use. Alternative embodiments are disclosed, including drop tube versions, for facilitating initial installation of the limitor on the top wall of a tank.

Description:
TECHNICAL FIELD 
     The present invention relates to the field of overfill protection devices or filling limitors for liquid storage tanks and, more particularly, to devices of the foregoing type that are especially suited for shallow tanks such as those known as “generator day tanks” used to store fuel for backup generators at hospitals and the like, or those found in or around homes to hold fuel oil for home heating. 
     BACKGROUND 
     Day tanks and home fuel oil tanks and the like are typically refilled by supply trucks that travel to the site and connect a hose from the truck to an inlet tube on the top wall of the tank. The hose is connected to the inlet tube in a sealed manner, and a pump on the truck delivers the fuel through the hose and into the tank under pressure. The tank typically has a vent that allows air to escape as the liquid level within the tank rises. Thus, although the supply line from the trunk to the tank is a sealed path, it is possible that the tank can become overfilled to such an extent that fuel spills out through the vent if the operator is not particularly attentive or if automatic shut-off mechanism at the truck fails to function properly. 
     Accordingly, there is a need for a way of shutting off additional inflow of fuel to the tank to prevent accidental overfilling and spillage, notwithstanding the presence of other shut-off mechanisms associated with the supply apparatus. While various types of electro-mechanical devices of this type are currently available, they suffer from numerous disadvantages, including cost and complexity. 
     SUMMARY OF THE INVENTION 
     The present invention provides a filling limitor or overfill protection device that is relatively simple, yet highly effective. It can be readily retro-fitted to existing tanks and is safe and reliable in operation. It is particularly well suited for shallow tanks in which the distance between the top and bottom walls of the tank is relative short, for example three feet or less. Although disposed within the flow path of incoming liquid, the valve of the device is capable of successfully resisting any tendency for the pressurized liquid to close the valve prematurely, which would result in only partial filling of the tank. 
     In one preferred embodiment of the present invention a poppet valve is housed within a tubular valve body and is moveable axially between open and closed positions by an external float that is operably coupled with the valve. Although the poppet is located within the tubular valve body that defines the flow path, the poppet is protected from direct engagement with the incoming pressurized liquid by an overhead deflector that is axially aligned with the poppet. Fluid that would otherwise engage the poppet and force it down against its seat to prematurely close the port through the valve body is instead diverted out radially upon engagement with the deflector so as to enter an annular region around the deflector and pass to and through the port without impinging the poppet. Consequently, the poppet is only shifted to its closed position when the float intentionally moves it to such position in response to the liquid within the tank reaching a predetermined level. 
     In a preferred embodiment the limitor comprises an assembly having as its two main components a mounting tube that is adapted to be threadably attached to the top wall of the tank and a valve subassembly that is threadably attached to the mounting tube. The subassembly comprises a cylinder having an annular, externally threaded boss at its upper end that is threadably received by the internally threaded lower end of the mounting tube. The cylinder defines an inlet port which is opened and closed by a poppet operating above the port along an axial path of travel relative thereto. The poppet has a valve stem associated therewith projecting above and below the poppet so as to be guided in its reciprocal travel by upper and lower guide structure supported by the cylinder. The upper guide structure serves also as a deflector overlying the poppet to divert liquid flow away from the poppet. At its lower end, the valve stem is mechanically coupled with an operating arm of the float which is supported laterally outside of the cylinder, such arm being swingable up and down by the rising and falling level of liquid within the tank to correspondingly manipulate the valve stem. 
     Various alternative embodiments are disclosed, including embodiments that utilize a drop tube extending down from the valve body for use in tanks that are not as shallow or where the incoming liquid is preferably delivered close to the bottom of the tank to avoid splashing or turbulence. The drop tube embodiments contemplate the provision of an opening in a sidewall of the drop tube that is sized to accept the float when the float is swung down and moved into the opening to present a slender profile for inserting the assembly through the hole in the top wall of the tank during installation. The opening in the sidewall is covered by an internally disposed cover that is spring biased toward the opening yet can be yieldably pushed into the interior of the drop tube by the float as the float enters the opening from outside the drop tube. The float arm is so designed in such embodiments that it can resiliently flex to a position permitting the float to be swung beyond its normal limit of travel into the inside of the drop tube, or the arm is of two-part, spring loaded construction to provide the desired amount of relief to permit the movement of the float to its installation position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary isometric view of a limitor constructed in accordance with the principles of the present invention and installed on the top wall of a storage tank; 
     FIG. 2 is an exploded isometric view of the limitor with parts broken away to reveal details of construction; 
     FIG. 3 is an assembled isometric view of the limitor with parts broken away to reveal internal details; 
     FIG. 4 is a top plan view of the limitor installed on the tank; 
     FIG. 5 is a vertical cross sectional view through the installed limitor taken substantially along line  5 — 5  of FIG.  4  and showing the poppet of the valve in its open position; 
     FIG. 6 is a vertical cross sectional view of the installed limitor taken substantially along line  6 — 6  of FIG. 4 with the poppet in its open position; 
     FIG. 7 is a vertical cross sectional view of the limitor similar to FIG. 6 but showing the poppet in its closed position; 
     FIG. 8 is an isometric view of an alternative embodiment which utilizes a drop tube; 
     FIG. 9 is an isometric view of the drop tube separately from the valve components of the limitor illustrating the manner in which the float maybe swung down into the interior of the drop tube for ease of installation; 
     FIG. 10 is a fragmentary vertical cross sectional view of the installed embodiment of FIGS. 8 and 9 illustrating the float forced inside the opening and the side of the drop tube for installation purposes; 
     FIG. 11 is a horizontal cross sectional view thereof taken substantially along line  11 — 11  of FIG. 10; 
     FIG. 12 is a horizontal cross sectional view there of taken substantially along line  12 — 12  of FIG. 10; 
     FIG. 13 is a fragmentary, vertical cross-sectional view of the drop tube embodiment showing the float in its valve open position; 
     FIG. 14 is a horizontal cross sectional thereof taken substantially along line  14 — 14  of FIG.  13 . 
     FIG. 15 is an isometric view of another drop tube embodiment wherein the operating arm of the float is jointed to provide the necessary over travel of the float for installation purposes; 
     FIG. 16 is an isolated view of the drop tube separate from the valve components of the limitor illustrating the way in which the float moves into the interior of the drop tube during its over travel for installation purposes; 
     FIG. 17 is an enlarged, fragmentary isometric view of the jointed operating arm of the float; and 
     FIG. 18 is an fragmentary, exploded isometric view of the operating arm of the float. 
    
    
     DETAILED DESCRIPTION 
     The present invention is susceptible of embodiment in many different forms. While the drawings illustrate and the specification describes certain preferred embodiments of the invention, it is to be understood that such disclosure is by way of example only. There is no intent to limit the principles of the present invention to the particular disclosed embodiments. 
     The limitor  10  as illustrated in FIG. 1 is mounted on the top wall  12  of a liquid storage tank. An annular flange  14  is welded to top wall  12  so as to be a permanent part of the tank and is axially aligned with a hole  16  in wall  12  as illustrated, for example, in FIG.  5 . The limitor  10  preferably is constructed to comprise two major components, i.e., a support tube  18  that becomes secured to flange  14 , and a valve subassembly  20  that becomes secured to and supported by tube  18  in use. 
     Support tube  18  has a series of upper external threads  22  at its upper end that are adapted to mesh with the internal threads of a coupling (not shown) on the end of a supply hose from a source of liquid such as, for example, a fuel truck. Generally adjacent its lower end, the tube  18  is provided with a lower set of external threads  24  that permit the tube  18  to be screwed into flange  14  and to project partially downwardly through the hole  16  in top wall  12 . A collar  26  around the exterior of tube  18  intermediate its opposite ends is provided with a series of wrench flats that facilitate screwing the tube  18  down into flange  14  during installation. A slightly reduced diameter lower portion  28  of tube  18  permits insertion of the latter down into and through flange  14 . 
     The valve subassembly  20  is adapted to be assembled to the tube  18  prior to installation of limitor  10  on the tank and includes a cylinder  30  having a reduced diameter, annular boss  32  at its upper end. Boss  32  is externally threaded so as to be threadably engaged with mating internal threads on the reduced diameter portion  28  of tube  18  when cylinder  30  is screwed up into tube  18 . A port  34  is provided within the boss  32  so as to communicate a tubular passage  36  of the tube  18  with a tubular passage  38  of the cylinder  30 . A poppet valve, denoted generally by the numeral  40 , is provided to open and close port  34 . 
     Poppet valve  40  includes an annular, beveled seat  42  that generally circumscribes port  34  at the upper end of boss  32 . A disk-like poppet  44  comprises another part of valve  40  and is carried by cylinder  30  for reciprocation between a closed position as shown in FIG. 7 in which poppet  44  sealingly engages seat  42  and an open position as shown, for example, in FIGS. 5 and 6 wherein poppet  44  is spaced axially above seat  42 . A valve stem  46  has an upper portion projecting upwardly beyond poppet  44  and a lower portion projecting downwardly from poppet  44  in coaxial alignment with port  34  and passages  36 , 38 . 
     A generally circular deflector  48  is disposed above poppet  44  in axial registration therewith. Deflector  48  is generally the same diameter as the poppet  44  except that, as shown particularly in FIG. 4, defector  48  has a pair of diametrically opposed ears  50  that project a short distance outwardly beyond the otherwise circular profile of deflector  48 . Ears  50  are provided with through holes that receive corresponding mounting screws  52  that are threaded down into boss  32 . A pair of tubular support members  54  are disposed between ears  50  and boss  32  so as to effectively space deflector  48  a fixed distance above port  34 , and such support members  54  freely receive the screws  52  so that members  54  are effectively clamped between deflector  48  and boss  32 . The outermost circumferential edge of deflector  48  is spaced radially inwardly from the interior wall surface  18   a  of tube  18  so as to define an annular flow region  56  through which incoming liquid may pass in order to reach port  34 . 
     The deflector  48  is provided with a centrally disposed guide hole  58  that reciprocally receives the upper end of valve stem  46 . Thus, deflector  48  serves the dual purposes of deflecting incoming liquid away from poppet  44  and guiding stem  46  during its reciprocation. At the other extreme, a transverse guide bar  60  spans the passage  38  just below port  34  to serve as a guide for the lower end of valve stem  46 , the bar  60  having a central guide hole  62  that reciprocally receives the lower end of stem  56 . 
     The valve subassembly  20  further includes a float  64  for operating poppet  44 . A generally L-shaped operating arm  66  is pivotally mounted on the cylinder  30  via a horizontally disposed pin  68  so that one leg  70  of arm  66  projects into the passage  38  while another leg  72  projects outwardly beyond the exterior of the cylinder  30 . Inner leg  70  is operably connected to the lower end of stem  46  via a pin and slot connection  74 , there being a transverse pin  76  in stem  46  that is received within an elongated slot  78  in leg  70 . Float  64  is cylindrical, and the outer leg  72  of arm  66  is fixed thereto at a location that is radially offset from the longitudinal axis of float  64 , the offset being such that the majority of the mass of float  64  is disposed outboard of leg  72 . 
     It will be noted that float  64  has an outer diameter that is less than the inside diameter of flange  14 . This facilitates field installation of limitor  10  as will be explained hereinbelow. In addition, it is to be noted that float  64  is supported on cylinder  30  at a point spaced a significant distance below the lower set of external threads  24  on tube  18 , which also facilitates installation of limitor  10  as explained below. The offset of float  64  with respect to the longitudinal axis of leg  72  of arm  66  is also important and beneficial for installation purposes. 
     It will be seen that the lower reduced diameter portion  28  of tube  18  is configured to present an internal, annular ledge  80 . This ledge has an inside diameter that is less than the distance between the outermost edges of the ears  50  of deflector  48 , as shown in FIG.  4 . To permit insertion of deflector  48  and its associated componentry up into the bottom end of tube  18  during assembly notwithstanding this over width dimension of deflector  48  from ear-to-ear, ledge  80  is provided with a pair of clearance notches  82  (FIGS. 4,  6  and  7 ) that are diametrically opposed to one another to clear corresponding ones of the ears  50  during initial insertion of the valve subassembly  20  up into the lower end of tube  18 . Once ears  50  have passed upwardly through and beyond notches  82 , they are no longer in interfering relationship with ledge  80  such that boss  32  can be screwed into the internal threads at the bottom of tube  18 . As particularly shown in FIGS. 4 and 5, boss  32  is provided with a drain hole  84  that maintains constant communication between passages  36  and  38  even when valve  40  is closed. 
     It will be appreciated that when support tube  18  and valve subassembly  20  are assembled together to make a complete limitor assembly  10 , tube  18  and cylinder  20  effectively become a single elongated tubular valve body that presents an internal flow passage comprised of the port  34 , the upper passage  36  and the lower passage  38 . Thus, although in the above described embodiment such body is defined and presented by two separate major components, it is within the scope of the present invention for the body to be integrally formed and of one piece construction. The operating principles remain the same in both cases, as explained below. 
     Operation 
     The installed limitor  10  is normally provided with a suitable closure cap (not shown) threaded onto the upper end of tube  18  via threads  22 . Such cap obviously needs to be removed at the time the tank is to be refilled with fuel or other liquid as appropriate. Once the closure cap has been unscrewed from tube  18  and the supply hose connected in its place, a sealed delivery path from the transport truck to the tank is established and refilling may begin. 
     FIGS. 1-6 illustrate valve  40  in its open condition in which the weight of float  64  has rotated operating arm  66  downwardly and shifted stem  46  upwardly until poppet  44  has engaged the bottom side of deflector  48 . Thus, in addition to its functions as an incoming liquid deflector and a guide for reciprocal stem  46 , the deflector  48  also serves as a limit stop for poppet  44  at the fully opened position of valve  40 . 
     With poppet  44  up against the underside of the deflector  48 , pressurized or non-pressurized liquid is free to move through limitor  10  and into the interior of the tank in a free-flowing manner. It will be noted that as the incoming liquid rushes down through passage  36  of support tube  18 , the central portion of such flowage encounters the deflector  48  and is diverted into annular flow region  56  around the periphery of the deflector. The entire mass of liquid then moves through region  56  and through the open port  34  before traveling into the passage  38  of cylinder  30  and discharging into the tank. Due to the presence of the overhead deflector  48 , the inrushing liquid does not impinge the top of poppet  44  on its way to and through port  34 . Instead, it merely rushes harmlessly through region  56  around the sides of poppet  44  without pushing down on poppet  44  in an effort to prematurely close it against seat  42 . On the other hand, it will be noted that float  64  is offset well to the side of discharging liquid from the lower end of cylinder  30  such that there is no tendency for the liquid to impede the operation of float  64  in any way. 
     As the liquid level rises in the tank, it engages float  64 , and eventually the buoyancy of float  64  causes it to float upwardly, rocking operating arm  66  in a counterclockwise direction viewing FIG. 6 so as to pull downwardly on valve stem  46  and cause poppet  44  to engage seat  42 , closing port  34 . This condition is illustrated in FIG. 7 wherein poppet  44  is fully seated against seat  42 . At that point, no further flow of liquid through port  34  can occur, although drain hole  84  as illustrated in FIGS. 4 and 5 permits liquid that is upstream from valve  40  within tube  18  and the supply hose to drain slowly into the tank. Typically, when valve  40  closes, a back pressure will develop within the supply hose sufficient to trip shut-off mechanism at the truck to disable the pump and terminate further delivery of liquid to the tank. Obviously, other means may be utilized to terminate further delivery, particularly in instances where limitor  10  is utilized for other applications that the home delivery of fuel oil. 
     Initial installation of the limitor on the tank can be quickly and easily effected. Even though the total width of limitor  10  from the outer lateral extremity of the float  64  to the far side of tube  18  and cylinder  30  exceeds the diameter of hole  16  and the internal diameter of flange  14 , the arrangement of components and other dimensions of limitor  10  are such that limitor  10  can still be installed through flange  14  and hole  16 . As noted earlier, the diameter of float  64  is less than the diameter of hole  16  and the internal diameter of flange  14 . Thus, during initial installation, the filly assembled limitor  10  is brought to the tank and the float  64  is the first part of the limitor to be inserted into place. By first aligning float  64  axially with flange  14  and hole  16 , float  64  may then be inserted down into the tank while the remaining structure consisting of the tube  18  and the cylinder  30  remain cocked at an angle above the flange  14 . Once float  64  is lowered into the tank far enough to clear top wall  12  and flange  14 , the limitor may be shifted laterally generally in the direction of the large open expanse on the top of float  64  until leg  72  is moved over into engagement or near engagement with the interior threads of flange  14 . This utilization of the offset relationship between float  64  and operating leg  72  permits the lower end of cylinder  30  to come into registration with the internal diameter of flange  14 , whereupon tube  18  and cylinder  30  may be manually rotated to become disposed into an upright orientation coaxial with flange  14  and hole  16 . Although this disposes float  64  to a laterally outboard position relative to the outer limits of hole  16 , this is of no consequence since float  64  is already well within the tank and no longer needs to pass through hole  16 . 
     Consequently, allowing the cylinder  30  and the lower end of tube  18  to then slip down into flange  14  and partially through hole  16  brings the external threads  24  of tube  18  into contact with the internal threads of flange  14 . The limitor  10  may then simply be screwed down into flange  14  using a wrench if necessary, although in many instances a manual manipulation is all that will be required. Float  64  merely rotates in a circle below top wall  12  as limitor  10  is screwed down into position. Once limitor is fully tightened down, it is ready for use. 
     Alternative Embodiments 
     FIGS. 8-14 are directed to a second embodiment of the invention wherein the limitor utilizes a drop tube as an extension to its lower end. As will be apparent to those skilled in the art, the limitor  110  of FIGS. 8-14 is identical in many respects to limitor  10 , and therefore much of the construction of the limitor need not be repeated at this point. Where appropriate, common components between the two embodiments will be similarly numbered in the second embodiment, with the addition of the prefix “1”. 
     As illustrated, a drop tube  186  projects downwardly from the lower end of the tubular body presented by the support tube  118  and the cylinder  130 . In the preferred form of limitor  110 , the upper end of the drop tube  186  is slipped onto and over the outside diameter of cylinder  130  until the upper end of drop tube  186  abuts the lower end of support tube  118 . Although not shown, it will be understood that drop tube  186  may be secured to cylinder  130  by self-tapping screws or other fasteners. The upper end of drop tube  186  is appropriately slotted to clear the operating arm  166  of float  164  as drop tube  186  is installed onto cylinder  130 . 
     Drop tube  186  must be attached to cylinder  130  before installation of limitor  110  onto the tank. Due to the length of drop tube  186 , however, which extends far below float  164 , it is not possible for the float  164  to be the lead component as limitor  110  is installed through flange  14  and hole  16  in top wall  12 . Thus, the entire profile of limitor  110  below external threads  124  on the lower end of support tube  118  must be slender enough to pass axially through the internal diameter of flange  14  and hole  16 . This is accomplished by providing a way for float  164  to be temporarily housed within the confines of drop tube  186  during installation. 
     In this regard, drop tube  186  is provided with a generally rectangular opening  188  in its sidewall directly adjacent float  164 . Such opening  188  is taller and wider than float  164  which, as illustrated in the figures, is preferably semi-circular in transverse configuration rather than being cylindrical as is float  64 . A cover  190  having height and width dimensions that exceed those of the opening  188  is located within the interior of drop tube  186  and normally lies up against and closes off opening  188  in overlapping relationship therewith. Cover  190  is preferably constructed of a plate-like spring metal with one end securely fastened to the wall of drop tube  186  by suitable fasteners such as rivets  192 . 
     Operating arm  166  is constructed of a resilient material that is normally sufficiently stiff as to avoid bending and flexing during normal operation. As illustrated in FIG. 13, for example, operating arm  166  holds float  164  out at an angle to drop tube  186  when the weight of float  164  keeps the poppet  144  up against deflector  148  in the fully open position of FIG.  13 . However, operating arm  166  is also sufficiently resilient as to allow flexure thereof as float  164  is manually pushed down beyond its valve open position of FIG. 13 into an installation position as illustrated in FIGS. 10-12 wherein float  164  has entered opening  188  and pushed spring-cover  190  back away from opening  188  and into a coiled up configuration. When float  164  is in this position, it presents no wider profile than the drop tube  186  itself, permitting axial insertion of the entire assembly through flange  14  and hole  16  during initial installation. Once float  164  has passed downwardly beyond flange  14  and top wall  12 , it is free to spring back out to its valve open position of FIGS. 8 and 13. 
     FIGS. 15-18 are directed to a third embodiment of filling limitor denoted by the numeral  210 . This embodiment is virtually identical to limitor  110 , with the exception of details of construction of the float and its operating arm. 
     In this respect, it will again be noted that limitor  210  is provided with a drop tube  286  having an opening  288  provided with a spring cover  290 . Once again, the intent is for float  264  to be placeable into opening  288  during installation so as to minimize the effective width of the overall assembly. However, instead of a resilient operating arm, float  264  is provided with a jointed operating arm  266 . 
     In this construction, the outer leg  272  of operating arm  266  is subdivided into two sections  272   a  and  272   b  that are interconnected by a transverse connecting pin  292 . A torsion spring  294  operably interconnects the two sections  272   a  and  272   b  and yieldably biases them toward their straight line orientation of FIG. 17, the construction of such sections being such that they interengage one another at the straight line configuration so as to prevent over travel past such position, although they can be pivoted relative to one another against the action of spring  294  in the opposite direction. 
     Accordingly, during installation, although float  264  would normally be disposed in its valve open position of FIG. 15 in which float  264  projects laterally outwardly from drop tube  286  for a substantial distance, float  264  maybe pushed down and around in a clockwise direction to enter opening  288  as jointed leg  272  pivots about pin  292  under the yieldable resistance of torsion spring  294 . Once inside the tank, spring  294  returns float  264  to its proper valve open position. 
     Although preferred forms of the invention have been described above, it is to be recognized that such disclosure is by way of illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
     The inventor(s) hereby state(s) his/their intent to rely on the doctrine of equivalents to determine and assess the reasonably fair scope of his/their invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.