Patent Publication Number: US-5829491-A

Title: Fuel overflow prevention system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to the field of fuel tank re-fueling devices. More particularly, the present invention relates to a device for prevention of fuel over-filling during re-fueling of a fuel tank. More particular yet, the present invention involves a fuel overflow prevention system particularly useful in a marine environment, where the system includes an optional audible signal to indicate fuel flow and level, and sealing features that account for expansion of fuel within the tank and to prevent fuel spillage. 
     2. Description of Prior Art 
     For as long as there have been fuel tanks and devices to refill them, there has been fuel spillage. Some contemporary estimates of fuel spillage are in excess of six million gallons annually in the United States alone. Globally, fuel spillage is many times this amount. The resultant fuel losses are economically and environmentally detrimental in terms of the wasted fuel resources and environmental contamination. Accordingly, numerous devices have been developed to prevent or otherwise limit fuel spillage during refueling. Known fuel containers that utilize such devices commonly include an intake, a fuel tank, and a vent. Typically, these devices are located in or around the intake and/or the vent. 
     In the field of fuel overflow prevention devices, there have been attempts to provide warning signals that indicate overflow conditions. It is to be noted at the outset, however, that these devices fail to account for expansion of the fuel within the tank. Nevertheless, while many fuel tanks have little in the way of a means for signalling that a tank is deemed to be effectively full, devices have been developed for that purpose. In general, there are two categories of such signalling devices. One category includes devices which are activated upon the fuel tank being filled reaching its defined full capacity, such devices typically being in the form of an audible alarm. The other category includes devices that disengage, or otherwise negate some constant signal, when the tank reaches a defined full fuel capacity. Such &#34;negative&#34; notification typically is in the form of an audible signal that is present during fueling but ceases when the tank is at or near full capacity. 
     The first category of overflow signalling devices having a signal activated only when the tank is full typically involves complexity are so complex that whatever advantages might otherwise be offered are undercut. Indeed, elaborate electronic sensing and signals have been developed with increased expense and complexity. Sensors in such devices are exposed to a variety of temperatures and petroleum distillates that may degrade the reliability of sensor components. The most serious aspect of this reliability problem in such prior-art devices is that sensor failure will not become apparent in the re-fueling process until after the tank has been overfilled and spillage has occurred. &#34;Negative&#34; activation alleviates much of this problem. 
     The second category of signalling devices utilizes &#34;negative&#34; activation by providing a constant signal during the fueling process that stops only when the tank is full. Although anyone using such a signalling device would readily notice if the device fails to produce the constant signal, other problems arise with such a device. Most commonly, a user will leave a fuel pump unattended during the re-fueling process. If the signal is an audible one, as it typically is, the user may be lulled into a false sense of control over the pump. When such a signal ceases, indicating that the tank is full, the user may then be unable to quickly access the pump so as to manually prevent overflow. Further, prior-art devices fail to substantially allow for thermal expansion of the fuel that can result in a full tank becoming &#34;over-full&#34; as the temperature rises. This can create a siphoning effect and a continuous fuel spill through the tank vent. One needs, therefore, to avoid filling the tank all the way. 
     Other related prior-art fuel overflow indicators have their own disadvantages. One prior-art re-fueling device is that of Delisle, Jr. et al. (U.S. Pat. No. 5,023,608) which involves a fuel filler alarm including a whistle and overflow reservoir combination that is attached to the vent hole of a fuel tank on a boat. The whistle in the Delisle device is designed to maintain an audible sound while fuel is being pumped into the fuel tank. When the fuel tank reaches its capacity, the whistle stops and, ideally, a fuel attendant will shut off the fuel pump. The device of Delisle does allow for some error by the fuel attendant such that excess fuel may be stored in the overflow reservoir; however, this is only a stop-gap measure that likely works only in situations where a relatively small amount of spilled fuel is involved. If a distracted fuel attendant is drawn away from the fuel pump for some extended period of time, fuel would certainly spill from an overfilled overflow reservoir. In addition, such a design is intended to allow the tank to be completely filled. Accordingly, Delisle fails to provide any gap in the tank for fuel expansion subsequent to being filled. 
     Other such prior-art re-fueling devices exist that are deficient for the same reasons. A general defect of prior-art is that there are no re-fueling systems which allow for thermal expansion subsequent to re-fueling while providing adequate signalling of proper fueling. It is well known to those skilled in the art of fuel production that fuel can expand by several percent over a temperature range of between about 60 and about 212 degrees fahrenheit--a range typically experienced by gasoline transferred from an underground storage tank to a boat&#39;s fuel tank during a hot summer day. Further, facilitation of the standard automatic-shut-off features of most fuel pumps by pressure-creating devices is absent in the prior-art. This type of fuel pump is widely-used throughout the retail gasoline market and operates generally by mechanically sensing the change in pressure in a fuel pump&#39;s nozzle to automatically stop fuel flow when the fuel reaches the nozzle. Two representative prior-art devices are those of Schupp (U.S. Pat. No. 5,181,022) and Langlois (U.S. Pat. No. 5,515,891). 
     Schupp includes a reservoir housing similar to Delisle but one having electronic sensors that signal an overfilled condition, rather than a constant signal that ceases upon a full-tank condition. This design of Schupp fails to provide for electronic failure caused by exposure of electronics sensitive to corrosive fuels and/or fuel additives. As well, the Schupp device may be susceptible to false sensing caused by fumes or small amounts of fuel splashed around the sensor that erroneously indicates the fuel has reached the capacity of the tank. Such problems may result in excessive overflow or even a boater&#39;s reliance on an erroneous indication that the tank is full. Similarly, Langlois includes primary and secondary fuel tanks and a full condition alarm that act in a fashion much like Schupp and Delisle. Langlois exhibits several flaws, including, most importantly, a lack of any sealing features that would create pressure sufficient to activate automatic-shut-off fuel pumps. 
     Accordingly, the prior art fails to provide any fuel overflow prevention device that provides &#34;negative&#34; notification with reliable control of fuel flow. Therefore, what is needed is a fuel overflow prevention device that provides signalling during re-fueling that ceases when the tank is just below its capacity, thereby indicating that fuel pumping should be turned off. What is also needed is such a device that provides automatic shut-off features for instances when fuel pumping is not manually turned off. Further, what is needed is such a device that ensures activation of standardized pressure-sensitive-pump-shut-off-triggers by providing a substantially sealed arrangement. Still further, what is needed is such a device that prevents fuel spillage that occurs due to thermal expansion of fuel. Yet further, what is needed is such a device that is relatively simple and not reliant upon electronics that may cause complete system failure with the failure of a relatively minor component. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a fuel overflow prevention device that ceases the re-fueling process at the point when the fuel level is just below the capacity of the fuel tank so as to allow for thermal expansion of the fuel within the tank. Another object of the present invention is to provide a device that automatically arrests fuel pumping during situations when a fueling attendant is preoccupied or when fuel pumping is otherwise not manually turned off. Yet another object of the present invention is to provide a fuel overflow prevention device with a substantially sealed arrangement that ensures activation of standardized pump-shut-off-triggers of the pressure-sensitive type. Still another object of the present invention is to substantially prevent any fuel siphoning effect out of the vent of the fuel tank. Additionally, another object of the present invention is to provide an optional signal--typically an audible whistle--during the re-fueling process to provide positive assurance to a fuel attendant that re-fueling is occurring properly. Another object of the present invention is to provide such a device that is principally mechanical in nature, and that may use, but does not require the use of, sensitive electronic components. 
     The device of the present invention primarily includes two separate parts that operate in conjunction with one another. Although this discussion focuses on use of the present invention in a marine environment, any similarly fragile environment may benefit from the inventive concepts disclosed herein. Also, for purposes of illustration, the present invention is discussed in terms of use within a fuel tank of a marine vessel; however, it should be understood that the fuel overflow prevention device is not intended to be limited to marine vessel fuel tanks. The invention may be utilized in a variety of ways including, but not limited to, buried or in-basement home heating oil tanks and fuel tanks of gasoline or diesel-engine land vehicles. 
     A fuel overflow prevention device according to the present invention is a two-part device that includes a fuel-fill nozzle adapter used in conjunction with a fuel discharge preventor. The adapter is substantially conical in shape with a truncated end and a hole through its center. The outer diameter is shaped to fit into a tank opening for an airtight fit; the inner diameter is shaped to accept the nozzle. This shape and its compressibility allows it to be inserted over a standard fuel-fill nozzle. The adapter easily fits over most nozzles because it is preferably fabricated of a neoprene rubber. While a specific shape and material is disclosed here, it should be understood that any similar shape or material may be used so long as the adapter is of a sufficient hardness and dimensions to provide a tapered, self-sealing sleeve and made from a fuel resistant material (i.e., neoprene rubber). The primary purpose of the adapter is to provide any standard fuel-fill nozzle with a sealed interference fit in substantially any diesel or gasoline tank intake, regardless of the size of the intake. 
     The second part of the present invention is the discharge preventer, which is placed in the vent of the fuel tank to be protected. The discharge preventor has a housing threadingly matable--or otherwise connectable by any suitable means such as welding, riveting, or interference-fit--to the vent. The vent is typically located on some portion of the top surface of the fuel tank and the discharge preventor is arranged substantially perpendicular to the top surface of the tank. The discharge preventor includes a signal tube located within the housing. The signal tube has one open end located within the tank and exposed to the fuel. The other end of the signal tube includes a signal tube mouth located within the housing but external to the tank. Aligned with the signal tube is a ball-cock valve. The ball-cock valve is located within the housing and between an exit port of the housing and the signal tube mouth and may rest on a ball-holding element such as a pin or spring. 
     The discharge preventor may further include a barbed elbow that facilitates connection of the housing exit port to a vent hose. Although an L-shaped connector with a barb is disclosed, any suitable connector that provides adequate venting ability should be considered within the intended scope of the present invention. Further, the signal tube mouth includes an audible-signalling means that is preferably a reed element that creates an audible whistle during tank re-fueling due to venting gases being displaced by fuel. This whistling provides the fuel attendant with audible verification that the tank is filling and not yet full. 
     In operation, the fuel overflow prevention device allows for safe re-fueling of both gasoline-powered and diesel-powered marine vessels. The tapered nozzle adapter securely fits the mouth of the fuel fill inlet. When used with a standard automatic shut-off fuel nozzle, the invention will shut itself off automatically upon fuel reaching a level determined by the installed height of the discharge preventor. A signal will sound while fuel is going into the tank and when the signal stops, fueling is complete. Even if the fuel attendant is neither alerted to the signal stopping nor tending the pump, the ball-cock valve within the discharge preventor will close and thus allows the pressure within the tank to increase so that the standard shut-off fuel nozzle is activated. 
     It is to be understood that other objects and advantages of the present invention will be made apparent by the following description of the drawings according to the present invention. While a preferred embodiment is disclosed, this is not intended to be limiting. Rather, the general principles set forth herein are considered to be merely illustrative of the scope of the present invention and it is to be further understood that numerous changes may be made without straying from the scope of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a fuel overflow prevention system in accordance with the preferred embodiment of the present invention showing a fuel tank being re-fueled. 
     FIG. 2 is a close-up view of a nozzle adapter according to the present invention on a standard fuel nozzle of the type shown in FIG. 1. 
     FIG. 3 is partial cut-away view of a fuel discharge preventor according to the present invention mounted on a standard fuel tank of the type shown in FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1, a fuel overflow preventor 11 and a nozzle adapter 10 are shown according to the preferred embodiment of the present invention. The overflow preventor 11 and adapter 10 are shown with a common fuel tank 13 that is being filled with fuel 14. The adapter 10 is designed to fit over a standard nozzle 12a of a common automatic-shut-off fuel pump handle 12. Fuel 14 is pumped through a hose 12b by a standard fuel pump (not shown) in a manner is well-known throughout the art. The adapter 10 is preferably conical in shape in order to provide a positive-interference fit with an opening 13b of the fuel tank 13. As shown further in FIG. 2, this preferred shape is substantially that of a truncated cone with an axial hole therethrough. This shape ensures that the adapter 10 fits over substantially all sizes of the nozzle 12a and into all sizes of opening 13b. Preferably, the adapter 10 is fabricated from a medium-hardness, neoprene rubber; however, any material that provides sufficient sealing between the nozzle 12a and inside of the opening 13b of the tank 13, and is substantially fuel resistant, may be suitable. Such sealing prevents leakage of tank gases or fuel through the opening 13b. 
     In FIG. 1 and FIG. 3, the fuel overflow preventor 11 is shown mounted to the fuel tank 13. The fuel overflow preventor 11 includes a housing 16. The housing 16 includes a threaded section 21 by which the fuel overflow preventor 11 is attached to the fuel tank 13. For purposes of definiteness, the fuel overflow preventor 11 is illustrated here as threadingly attached to a threaded fuel tank hole 13c; however, any suitable manner of connection may be used to mount the fuel overflow preventor 11 to the fuel tank 13. 
     Additional reference to FIG. 3 discloses that the housing 16 includes a vent tube 15 and a signal tube 17 serially arranged therethrough. Between the vent tube 15 and the signal tube 17 is a fuel blocking component that is preferably a ball 18. A ball-holding component, such as a spring 19 shown in FIG. 3, or a fixed cross pin (not shown) is located within the signal tube 17. The ball-holding component is designed to be lightly loaded and is further designed to hold the ball 18 within the signal tube 17 just above a signal element 20. A pin may be used instead of the spring 19 so as to reduce any detrimental effect that may be caused by complete or partial failure of the spring 19. The vent tube 15 has a ball-seat 15c located at one end and an exit vent 15b located at the other end. The exit vent 15b includes a barb 15a upon which a vent hose (not shown) may be mounted in order to vent fuel tank gases away from the area of the fuel tank 13, possibly for recovery. The signal tube 17 includes the signal element 20 and an intake 17a located at opposite ends thereof. While the signal element 20 is shown as a slotted whistle, any suitable design may suffice such as a reed element. The signal element 20 provides an audible whistling sound as gases within the fuel tank 13 are forced from the intake 17a to the exit vent 15b via the signal element 20 as fuel 14 fills the tank 13. 
     In operation, the adapter 10 and fuel overflow preventor 11 act together as a fuel overflow prevention system. During re-fueling, fuel 14 will be pumped into the tank 13 through the nozzle 12a of the standard automatic-shut-off pump handle 12. The nozzle 12a fitted with adapter 10 will ensure that substantially all gases displaced by the fuel 14 exits through the fuel overflow preventor 11. As these gases pass through the fuel overflow preventor 11 via signal tube 17 and vent tube 15, an audible whistling sound is created by the signal element 20. This sound alerts the person attending to the re-fueling that the re-fueling process is progressing as it should. As the amount of the fuel 14 increases in the tank 13, the empty space in the tank 13 reaches a predetermined level. This predetermined level is a fuel expansion allowance. 
     The fuel expansion allowance is set by the distance between the plane including a top surface 13a of the fuel tank 13 and the plane including the intake 17a. This distance is dictated by the thermal coefficient of expansion of the specific fuel used and the tank shape. The more the fuel used is predicted to expand, the greater the distance needed. When the rising fuel 14 reaches the intake 17a, intake 17a is sealed off from the gas space and displaced gases cease to flow through the signal element 20. This results in a cessation of the whistle sound that alerts the fuel attendant that the fuel tank 13 is full. Regardless of whether the fuel attendant is inattentive or, alternatively, engages the automatic-shut-off pump handle 12 and leaves the pump unattended, the instant overflow prevention system will ensure that pressure increases within the tank 14 sufficient to activate the automatic-shut-off feature of handle 12. The pressure increase is facilitated by ball 18 which seats itself on the ball-seat 15c when the fuel expansion allowance is attained. Thus, gases are exhausted through ball-seat 15c until the ball 18 is seated. This seating results in a total cessation of the audible whistling sound. 
     It should be understood that the preferred embodiment mentioned here is illustrative of one variation the present invention and that numerous design modifications and variations in use of the present invention may be contemplated in view of the following claims without straying from the intended scope and field of the invention herein disclosed.