Apparatus and method for grounding compressed fuel fueling operator

BACKGROUND OF THE INVENTION

The present invention is directed to a safety system and a method for grounding an operator at fueling station during the compressed fuel fueling process.

Fueling the fuel tanks of vehicles and other mobile apparatus with gaseous fuels such as hydrogen or compressed natural gas can be accomplished rapidly by discharging the fuel from high pressure storage vessels into, for example, the fuel tank or storage vessel in the vehicle or other mobile apparatus requiring fuel. It is imperative that the fuel be delivered safely to the vehicle. The point of the fueling process that may pose a potential hazard occurs when the operator disconnects the fuel fill nozzle from the vehicle. The operator may have built up static charge upon his or her person. If there is a leak of fuel from the station or vehicle, then, as the operator tries to remove the nozzle, a spark from a static discharge may ignite the gaseous fuel.

This may also be a hazard with liquid fuels. However, to date, the industry has not adequately addressed the problem. This may change since there were more than forty reports of gasoline fires due to operator static in the combined years of 1999 and 2000.

In the past, there have been a limited number of known attempts to directly address fueling of vehicles with compressed gas and the problem of potential fires due to static discharge. For example, in U.S. Patent No. 5,029,622 (Mutter), an automated process for filling a vehicle with a compressed gas is described. However, there is no disclosure related to reducing or eliminating the problem of static discharge from the operator during the fuel filling operation.

It is known that vehicle static discharge may be avoided by use of a conductive fuel hose. This may be done for both gasoline as well as natural gas vehicles pursuant to National Fire Protection Association Code NFPA 77 "Recommended Practice on Static Electricity." Section 4-5.3.6. of NFPA 77 states "all metallic parts of the fill pipe assembly should form a continuous electrically conductive path downstream from the point of bonding. For example, insertion of a nonconductive hose equipped with a metal coupling on the outlet must be avoided unless the coupling is bonded to the fill pipe."

In Von Pidoll et. al. "Avoidance of Electrostatic Hazards During Refueling of Motorcars," <i>Journal of Electrostatics,</i> 40 &amp; 41, 1997, pages 523-528, the authors note that there were more than 30 ignitions of gasoline/air mixtures at public filling stations in Germany in a particular time period. One of their recommendations is the use of antistatic seats in all cars. This suggestion has not been accepted for gasoline cars to date, and it does not seem that this recommendation will be accepted for alternative fuels in the near future. This suggestion also does not protect the operator from other sources of static buildup such as their clothes.

In Kassebaum &amp; Kocken, "Controlling Static Electricity in Hazardous (Classified) Locations," IEEE Trans. On Indus. Applics., Vol. 33, No. 1, Jan./Feb. 1997, the authors recommend the use of conductive soled shoes for certain areas where there is potential for fire due to presence of flammable liquids, gases and dusts. A fueling station for the fueling of, for example, hydrogen gas, as used in the present invention, can be considered such an area where conductive soled shoes might be recommended. However, it cannot be expected that customers of fueling stations for hydrogen fuel for, for example, a fuel cell powered vehicle, have the correct footwear if such hydrogen fuel stations are going to be widely commercialized.

It is principally desired to provide a safety system and method for grounding an operator at a fueling station prior to removing a fuel fill nozzle from a fuel tank upon completion of a fuel filling operation.

It is further desired to provide a safety system and method for grounding an operator at a fueling station prior to removing a fuel fill nozzle from a fuel tank upon completion of a fuel filling operation that is simple and relatively inexpensive.

It is still further desired to provide a safety system and method for grounding an operator at a fueling station prior to removing a fuel fill nozzle from a fuel tank upon completion of a fuel filling operation that is not prone to operator error.

Finally, it is desired to provide a safety system and method for grounding an operator at a fueling station prior to removing a fuel fill nozzle from a fuel tank upon completion of a fuel filling operation that is specifically for use for hydrogen in fuel cell tanks, but may also be used with respect to filling other fuel tanks with flammable fuels.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to the grounding of such an operator subsequent to the filling operation and prior to removal of the fuel fill nozzle. In the present invention, the operator is notified that he must ground himself prior to removal of the nozzle, or the nozzle.

While the present invention addresses grounding of an operator while filling a fuel cell tank with hydrogen, all embodiments of the present invention apply equally well to filling a fuel tank with a flammable gas or flammable liquid that emits flammable vapors, such as gasoline. It is believed that the present invention is the first attempt to solve the problem of potential static discharge at the end of a vehicle fill process by the grounding of the fuel fill operator.

A safety system and a method for grounding an operator at a fueling station according to the present invention are defined by claims 1 and 2.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

<ul id="ul0001" list-style="none" compact="compact"><li>FIG. 1 is a simplified schematic diagram of a fueling station in combination with a fuel dispenser and fuel storage vessel in accordance with one preferred embodiment of the present invention.</li><li>FIG. 2 is a simplified view of a nozzle and port in accordance with a preferred embodiment of the present invention, for use in the fuel filling station of FIG. 1.</li><li>FIG. 3 is a simplified view of a nozzle and port in accordance with a second preferred embodiment of the present invention, for use in the fuel filling station of FIG. 1.</li></ul>

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to apparatus and methods for grounding an operator during a fuel filling operation immediately before removing the fuel fill nozzle from the vehicle by the operator. By using the present invention, static discharge from the operator during the nozzle disconnection process will not likely cause ignition of fuel or vapor that has leaked from the fuel nozzle/vehicle fuel port area during the normal fueling process.

While this invention is primarily directed to a fuel filling process for filling hydrogen gas in a fuel cell fuel tank, the present invention would apply equally well to filling a fuel tank with any flammable gas or flammable liquid that emits flammable vapors, such as gasoline.

It is preferred that grounding of the operator occur at a grounding point adjacent to the fuel tank port of the vehicle. For purposes of the present invention, "adjacent" means a distance that is any suitable distance between the fuel tank port and the grounding point. For example, the distance between the dispenser and the fuel tank port, or, for example, two to ten feet or even more may typically be appropriate. Any distance of at least two centimeters will likely allow for proper grounding in accordance with this invention.

Referring now to the drawings, wherein like reference numbers refer to like elements throughout the several views, there is shown in FIG. 1 a safety system 5 for grounding an operator at a fueling station 10 prior to removing the fuel fill nozzle 22 from the fuel tank port 32 of the vehicle 24.

For purpose of the present invention, vehicle 24 means a vehicle such as an automobile or other mobile or portable apparatus that has a fuel tank 26 that is to be filled with a flammable gas or liquid fuel.

The fueling station 10 consists of a station controller 12 which may be located in a fuel dispenser 14 or elsewhere in the station 10. The station 10 will also include a source of compressed fuel such as a fuel storage vessel 16, fuel flow controller 18 for controlling flow of fuel, and a monitor 20 for the monitoring flow of fuel. Again, the fuel flow controller 18 and monitor 20 may be located in the dispenser 14, or elsewhere in the station 10. The fuel flows from the fuel storage vessel 16 through a fuel conduit 28 to a fuel flow nozzle 22. The fuel flow nozzle 22 mates with the fuel tank port 32 in the vehicle 24. The dispenser will also have a resting place, or boot, 33, for supporting the nozzle when not filling the vehicle.

FIG. 2 depicts an embodiment of the safety system of the present invention. For the sake of simplicity, like parts shown in FIG. 1 will be designated with a threehundred series number. For example, nozzle 22 in FIG. 1 will be designated nozzle 322, and the safety system 5 will be designated 305.

Here, a fuel fill nozzle 322, a fuel tank nozzle port 332 and a grounding device 344 are included. The grounding device includes a contact member 344A that is connected to ground. The grounding device 344 also includes a grounding switch 350. The fuel controller 18 (see FIG. 1), for controlling fuel flow through the nozzle, is included wherein when the contact member 344A of the grounding device 344 is contacted, thereby activating the grounding switch 340, the fuel controller 18 provides for fuel to flow. If the contact member 344A is released or when the fuel tank 326 has reached capacity, the fuel controller 18 causes fuel to stop flowing. The fuel controller 18 then provides a signal to an indicator 345, such as a display screen or light that indicates to the operator, immediately upon receiving the signal, that grounding must take place prior to removal of the nozzle.

FIG. 3 depicts another alternate embodiment of the safety system of the present invention. For the sake of simplicity, like parts with respect to the first embodiment will be designated with a four hundred series number. For example, nozzle 322 in the first embodiment will be designated nozzle 422 in this embodiment, and the safety system is 405.

This embodiment includes only a fuel fill nozzle 422, a fuel tank nozzle port 432, a grounding device 444, a fuel flow controller 18 (see FIG. 1), and an indicator 445. When the fuel flow controller 18 senses that fuel is no longer flowing, either due to the fuel tank being full or the operator shutting off flow of fuel, the fuel flow controller sends a signal to the indicator 445 to indicate to the operator that he or she should contact ground prior to removal of the nozzle from the port.

In use, in all of the above systems, the operator places the nozzle in the port and performs the appropriate required function based on the above systems in order to withdraw the nozzle from the port.

Although illustrated and described herein with reference to specific embodiments, the present invention nevertheless is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the subject-matter of the appended claims.