Fluent material handling – with receiver or receiver coacting mea – Processes
Reexamination Certificate
2001-05-22
2002-06-11
Maust, Timothy L. (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Processes
C141S094000, C141S098000, C141S192000, C141S197000, C362S215000, C362S216000, C307S326000
Reexamination Certificate
active
06401767
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
BACKGROUND OF THE INVENTION
The present invention is directed to apparatus and methods for fueling fuel tanks with compressed fuel. In particular, the present invention is directed to the grounding of an operator 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. Pat. 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,”
Journal of Electrostatics
, 40 &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 & Kocken, “Controlling Static Electricity in Hazardous (Classified) Locations,”
IEEE Trans. On Indus. Applics
., Vol. 33, No. 1, January/February 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 either notified that he must ground himself prior to removal of the nozzle, or the nozzle itself is locked into the vehicle port. Automatic nozzles that lock and unlock to a vehicle port have been built for natural gas vehicle (NGV) service, for example, the WEH GmbH of Germany, nozzle type WEH TK 18, but none is locked or unlocked by action of grounding.
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.
The first embodiment of the present invention is directed to a safety system 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. The safety system includes a fuel tank port in communication with the fuel tank for receiving and retaining the fuel fill nozzle during the fuel filling operation. The safety system further includes a grounding device adjacent to the fuel tank port which includes a grounding switch having a contact member that receives physical contact by the operator. Physical contact of the contact member by the operator activates the grounding switch. A releasable interlock is also included that provides a lock position wherein the nozzle is locked into the port upon insertion of the nozzle into the port and a release position wherein the nozzle is releasable from the port upon completion of the fuel filling operation and after physical contact of the contact member is accomplished. Accidental ignition of fuel due to static discharge is thereby prevented.
Preferably, the grounding device is located at least two centimeters from the nozzle. Additionally, it is preferable that the fuel source contain a compressed fuel and the fuel is hydrogen.
The releasable interlock may be a manually activated nozzle lever, wherein movement of the nozzle lever in a first direction locks the nozzle to the fuel tank port and wherein movement of the nozzle lever in a second direction unlocks the nozzle from the fuel tank port only upon activation of the grounding switch. Preferably, the first direction and the second direction are opposed, i.e., are directed 180 degrees from one another. For example, the first direction may be toward the left and the second direction may be toward the right, although such feature is not essential or required. Many combinations of first and second directions can be engineered without undue experimentation.
A timer may be included that is connected to the releasable interlock where the timer provides for the releasable interlock to remain in the release position for a limited time period subsequent to activation of the grounding switch. The timer provides for the releasable in
Cohen Joseph Perry
Farese David John
Xu Jianguo
Air Products and Chemicals Inc.
Gourley Keith D.
Maust Timothy L.
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