WO2004100302A1

WO2004100302A1 - Method and article of manufacture to effect an oxygen deficient fuel cell

Info

Publication number: WO2004100302A1
Application number: PCT/US2003/013546
Authority: WO
Inventors: James D. Pinney
Original assignee: Pinney James D
Priority date: 2003-05-01
Filing date: 2003-05-01
Publication date: 2004-11-18
Also published as: AU2003237142A1

Abstract

A method and article of manufacture for effecting an oxygen deficient fuel cell wherein an oxygenless gas is introduced to the internal structure of a fuel cell as fuel volume is diminished thereby displacing ambient air containing oxygen with said oxygenless gas.

Description

METHOD AND ARTICLE OF MANUFACTURE TO EFFECT AN OXYGEN DEFICIENT FUEL CELL

Technical Field of the Invention

The instant invention relates in general to fuel cells and in particular to a method and

article of manufacturing for replacing ambient air containing oxygen within a fuel cell with

an oxygenless gas, such as, but not limited to, propane, helium, or nitrogen.

Background of the Invention

The practice of inerting a gas into a fuel cell, particularly fuel cells such as aircraft

fuel tanks is well known in the art. For example:

United States Patent No. 2,870,936 issued to A.J. Clayton on January 27, 1959

discloses a closed system for venting and inerting aircraft fuel tanks.

United States Patent No. 3,587,618 issued to Richard L. Kenyon on June 28, 1971

discloses a fire and explosion prevention system for aircraft fuel tanks that utilizes an inert

gas for pressurizing the fuel tanks and in which means is provided for preventing over-

pressurization of the fuel tanks in case of either clogging of vent passages that normally

connect the fuel tanks to atmosphere or failure of vent valves to open, hereafter referred to

as the "618" patent.

Quite distinct from the '618 patent which uses liquid nitrogen and thus requires

refrigeration to maintain the operational effectiveness of such nitrogen, the instant invention

utilizes a gaseous form of nitrogen. A further distinguishing characteristic and benefit of the instant invention is its utilization of a containment vessel requiring far less space than any

refrigeration unit associated with the '618 invention. Further, the instant invention

eliminates the attendant weight of the '618 refrigeration unit by replacing the '618's liquid nitrogen with a gaseous form of nitrogen contained within a comparatively small pressurized

tank.

United States Patent No. 3,590,559 issued to Kenneth R. Bragg et al. on July 6,

1971 discloses an inerting system to prevent fire and explosion within aircraft or other fuel

tanks by maintaining in the ullage thereof an inert atmosphere and by removing oxygen from

the fuel when pressure on the fuel decreases, as during the climb of aircraft, such removal

of oxygen being accomplished by injecting a mixture of fuel and an inert gas into the fuel

supply through submerged nozzles.

United States Patent No. 3,732,668 issued to Richard A. Nichols on May 15, 1973

discloses a system for inerting aircraft fuel tanlcs comprising mixing of the fuel and an inert

gas within a tube whereby the inert gas scrubs the fuel of oxygen dissolved therein and

dilutes the same, the mixture being discharged from the tube into the fuel tank where the

inert gas and the oxygen rise to the tank vapor space where a portion of the same may be

vented to atmosphere but in any case the oxygen

content in the vapor space is less than about 12 percent whereby flame and explosion cannot

propagate within the tank.

United States Patent No. 3,788,040 issued to Kenneth R. Bragg et al. on January

29, 1974 discloses a method of maintaining the ullage of a previously inerted aircraft fuel

tank in the inert condition under which combustion cannot take place within the tank during

the after filling of the tank with liquid fuel, and during flight of the aircraft. The method ,

utilizes the oxygen lean ullage gases for scrubbing oxygen from incoming fuel during filling

of the tank, separating the gases having scrubbed oxygen therein from the incoming fuel and

venting the same to the exterior of the tank so as not to raise the oxygen content of the gases remaining in the ullage.

United States Patent No. 4,378,920 issued to Joe N. Runnels et al. on April 5, 1983

discloses a combustibly inert air supply system and method wherein compressed air is

directed through an inert gas generator which removes oxygen to produce a nitrogen

enriched, combustibly inert air or gas. The converter is sized to only meet the relatively low

flow rate requirements of the system during which times the combustibly inert air or gas is

delivered directly to a utilization site. The system further includes a high pressure storage

container in which a pressurized precharge of the combustibly inert air or gas is stored.

Combustibly inert air is released from such high pressure storage container for providing the

higher flow rate requirements of the system. The system may be used aboard an aircraft for

inerting fuel tanks. It may include a separate compressor for filling the high pressure storage

container.

In view of the limitations and disadvantages of the afore cited prior art, it is apparent

that what is needed is an improved method and article of manufacture to effect an oxygen

deficient fuel

cell which will minimize potential for flame and explosion within an aircraft fuel tank. A

need met and exceeded by the instant invention.

Brief Summary of the Invention

A method and article of manufacture to effect an oxygen deficient fuel cell which

will minimize the potential for flame and explosion occurring within an aircraft fuel tank.

A first containment vessel contains a pressurized oxygen-free gas, such as, but not

limited to, propane, nitrogen or helium. The containment vessel is first connected to a

pressure regulator via a pressurized conduit. The pressurized conduit can be constructed of

any material capable of transporting oxygen-free gas in a pressurized environment. Said

conduit is utilized to facilitate the transport of said oxygen-free gas from the first

containment vessel to and through a pressure regulator continuing to and through a demand

regulator exiting said demand regulator and entering into a fuel cell. The fuel cell also

comprises a exiting gas outflow conduit and outflow valve. In an alternative embodiment

of the instant invention an oxygen sensor can be attached to either the exiting gas outflow

conduit, the outflow valve or integrated within the outflow valve to sample for and signal

the presence of oxygen within the fuel cell.

The invention is practiced by charging the internal portion of a fuel cell with a

hydrocarbon based fuel, such as but not limited to aviation fuel.

An object of the instant invention is to minimize the potential for flame and

explosion occurring within an aircraft fuel tank.

A further object of the instant invention is to eliminate excessive weight restrictions

attendant to prior art approaches to minimize the potential for flame and explosion occurring

within an aircraft fuel tank. Yet another object of the instant invention is to provide a comprehensive, yet

uncomplicated method and apparatus to effect an oxygen deficient fuel cell.

Other objects and further scope of the applicability of the present invention will become apparent from the detailed description to follow, taken in conjunction with the

accompanying drawings wherein like parts are designated by like reference numerals.

Description of the Drawings

Figure 1 is an illustration of operational components necessary to effect the practice

of the invention's preferred embodiment.

Detailed Description of the Preferred Embodiment

While the making and using of various embodiments of the present invention are

discussed in detail below, it should be appreciated that the present invention provides for

inventive concepts capable of being embodied in a variety of specific contexts. The specific

embodiments discussed herein are merely illustrative of specific manners in which to make

and use the invention and are not to be interpreted as limiting the scope of the instant

invention.

The claims and the specification describe the invention presented and the terms that

are employed in the claims draw their meaning from the use of such terms in the

specification. The same terms employed in the prior art may be broader in meaning than

specifically employed herein. Whenever there is a question between the broader definition

of such terms used in the prior art and the more specific use of the terms herein, the more

specific meaning is meant. While the invention has been described with a certain degree of particularity, it is

clear that many changes may be made in the details of construction and the arrangement of

components without departing from the spirit and scope of this disclosure. It is understood

that the invention is not limited to the embodiments set forth herein for purposes of

exemplification, but is to be limited only by the scope of the attached claim or claims,

including the full range of equivalency to which each element thereof is entitled.

Figure 1 illustrates the invention's preferred embodiment for effecting an oxygen

deficient fuel cell. A first containment vessel 5 contains a pressurized oxygen-free gas, such

as, but not limited to, propane, nitrogen or helium. The containment vessel is first connected

to a pressure regulator 10 via a pressurized conduit 15. The pressurized conduit 15 can be

constructed of any material capable of transporting oxygen-free gas in a pressurized

environment. Said conduit 15 is utilized to facilitate the transport of said oxygen-free gas

from said first containment vessel 5 to and through a pressure regulator 10 at a reduced

pressure 16 continuing to and through an electric, vacuum or otherwise actuated demand

regulator 20 exiting said demand regulator 20 and entering into a fuel cell 25. The fuel cell

25 also comprises a exiting gas outflow conduit 33 and outflow valve 30. Said outflow

valve 30 designed and purposed to ensure pressure limits within the fuel cell 25 do not

exceed limits established by the fuel cell manufacturer for safe and efficient operation of the

cell. In an alternative embodiment of the instant invention an oxygen sensor 34 can be

housed within the fuel cell 25, attached to the exiting gas outflow conduit 33, the outflow

valve 30 or integrated within the outflow valve 30 to sample for and signal the presence of

oxygen within, or exiting the fuel cell 25. For applications presently embodying a one way

outflow valving mechanism, such as certain aircraft types, the present invention, in an alternative embodiment can be fitted to accommodate the existing mechanism for venting

purposes.

The invention is practiced by charging the internal portion of a fuel cell 25 with a

hydrocarbon based fuel, such as but not limited to aviation fuel. Said charging effectuates

the displacement of pre-existing ambient air residing within the fuel cell 25 insufficient

volume effecting a combustionable flashpoint. Fueling (a.k.a. "charging") continues until

such time as the fuel cell 25 is either filled with the introduced fuel source 38 or

alternatively, until a desired amount of fuel 38 has entered the fuel cell 25. Should the fuel

cell 25 contain oxygen levels in excess of that necessary to effect combustion, the cell 25

is further purged of such oxygen laden ambient air by further introducing said oxygen

deficient gas is transported from the first containment vessel 5 through pressure regulator

10 continuing through demand regulator 20 and into the fuel cell 25 until ambient air within

said fuel cell 25 possesses oxygen levels below that necessary to effect and system

combustion. Said purging just described to be effectuated by overriding demand regular 20

pressure limitations and allowing for venting of said ambient air via the invention's gas

outflow conduit 33 and outflow valve 30. Though the present invention allows for varying

degrees of pressurization, it has been determined through experimentation and modeling that

for aviation purposes, that the oxygen-free gas having been initially pressurized to

approximately 3000 psi while resident in a first containment vessel 5, such pressure should

be reduced to an approximate effective operating pressure of 75 psi upon exiting 18 the

pressure regulator 10 through the demand regulator 20, then lowered again 17 to a pressure

consistent with that existing within the fuel cell 25. As other applications of the instant

invention may require varying degrees of pressurization, those reasonably skilled in the relevant art can effect an operationally efficient pressurization for such applications by

modifying pressure regulator 10 and demand regulator 20 settings.

The instant invention maintains its operational efficiency by introducing said

pressurized oxygen deficient gas to the internal portion of the fuel cell simultaneously with

the diminishing of the previously introduced fuels 38 volume. As the fuel volume is

diminished within the internal portion of the fuel cell 25 the demand regulator 20 allows for

the further introduction of oxygen-free gas 35 into the fuel cell 25.

The invention further provides for releasing said pressurized oxygen deficient gas

35 whenever the pressure within the internal structure of the fuel cell exceeds a pressure

necessary to effectuate and maintain application operational efficiency. Such exiting of

oxygen-free gas 35 is facilitated by an exiting gas outflow conduit 33 attached to an outflow

valve 30.

An alternative embodiment of the instant invention would allow for quick

connect/disconnect components to be attached to any juncture between the pressurized

conduit 15 and first containment vessel 5, pressure regulator 10, demand regulator 20, and

fuel cell 25. Said quick connect/disconnect means may also be employed with respect to the

utilization of the upflow exiting conduit 33, outflow valve 30 and/or oxygen sensor 34. As

will readily be appreciated by those skilled in the art, the ability for quick

connect/disconnect greatly reduces or eliminates the labor associated with removing and

replacing operational components of the instant invention while reducing fatigue on more

strenuously attached coupling mechanisms.

The instant invention application can be readily appreciated and envisioned with

respect to its use in the aviation industry. In such an application, the fuel cell 25 would be represented as the fuel containment capacity of an aircraft fuel cell typically manifested as

the internal construct of an aircraft wing. The containment vessel within which the

oxygenless gas resides prior to introduction to the fuel cell 25 can be located in any

convenient environment allowing for rapid servicing by ground personnel during routine

practice of the invention. Such locations would include but not be limited to an airplane

cockpit, tail structure, internal cabin, or any space available which would provide adequate

load bearing and volume capacity to house the containment vessel 5 for an appropriate

aircraft application. Such environments would typically vary with respect to the aircraft

utilized. A 747 passenger airliner would obviously require a greater space to house the

containment vessel 5 while smaller applications in private aircrafts would require less space.

Though the invention in its preferred embodiment utilizes a demand regulator 20 to

determine when additional oxygen-free gas should be introduced to the fuel cell 25, a

combination of valves allowing for such introduction and sensors well known to those

skilled in the art could be used in an alternative configuration.

While this invention has been described to illustrative embodiments, this description

is not to be construed in a limiting sense. Various modifications and combinations of the

illustrative embodiments as well as other embodiments will be apparent to those skilled in

the art upon referencing this disclosure. It is therefore intended that this disclosure

encompass any such modifications or embodiments.

Alternate Embodiments

The foregoing description, for purposes of explanation, used specific nomenclature

to provide a thorough understanding of the invention. However, it will be apparent to one

skilled in the art that the specific details are not required in order to practice the invention. In other instances, well lαiown circuits and devices are shown in block diagram form in

order to avoid unnecessary distraction from the underlying invention. Thus, the foregoing

descriptions of specific embodiments of the present invention are presented for purposes of

illustration and description. They are not intended to be exhaustive or to limit the invention

to the precise forms disclosed, obviously many modifications and variations are possible in

view of the above teachings. The embodiments were chosen and described in order to best

explain the principles of the invention and its practical applications, to thereby enable others

skilled in the art to best utilize the invention and various embodiments with various

modifications as are suited to the particular use contemplated. It is intended that the scope

of the invention be defined by the following claims and their equivalents.

Although the present invention has been described with reference to the aviation

industry, it is not limited to this particular application. Utilization of the present invention in any application utilizing volatile fuel within a pressurized fuel cell can be ready

appreciated by those skilled in the art.

Claims

What is claimed is:

1. An oxygen deficient fuel cell comprising:

a first containment vessel containing a pressurized oxygen free gas;

a pressure regulator attached to said first containment vessel via a pressurized

conduit; said pressurized conduit capable of transporting said pressurized oxygen

a demand regulator attached to said pressure regulator via said pressurized

conduit;

a fuel cell attached to said demand regulator via said pressurized conduit;

an outflow valve attached to said fuel cell via an exiting gas outflow

conduit.

2. The fuel cell of claim 1 wherein said pressurized conduit is connected to said containment vessel via a connecting means allowing for rapid attachment and

detachment of said containment vessel to said pressurized conduit.

3. The fuel cell of claim 1 further comprising an oxygen detection sensor attached to

said exiting gas outflow conduit.

4. The fuel cell of claim 1 further comprising an oxygen detection sensor attached to

said outflow valve.

5. The fuel cell of claim 1 further comprising an oxygen detection sensor integrated within to said outflow valve.

6. The fuel cell of claim 1 further comprising a plurality of containment vessels,

pressure regulators, demand regulators, fuel cells, pressurized conduits, exiting gas

outflow conduits and out flow valves.

7. The fuel cell of claim 1 further comprising a plurality of pressure regulators, demand

regulators, fuel cells, pressurized conduits, exiting gas outflow conduits and out flow

valves.

8. A method to effectuate utilization of an oxygen deficient fuel cell comprising:

charging the internal portion a fuel cell with a fuel; said charging effectuating

the displacement of pre-existing ambient air residing within said fuel cell;

introducing a pressurized oxygen deficient gas to the internal portion of said

fuel cell; said introduction occurring concurrently with diminishing of said fuel's

volume;

pressurizing said fuel cell to a level necessary to effect and maintain

application operational efficiency.

9. The method of claim 8 wherein said pressurizing further comprises releasing said

pressurized oxygen deficient gas whenever said pressure within said fuel cell

exceeds a pressure threshold necessary to effectuate application operational

efficiency.

10. The method of claim 8 wherein said charging further comprises the introduction of

a pressurized oxygen deficient gas to the internal portion to displace pre-existing ambient air residing within said fuel cell.

11. The method of claim 8 wherein further comprising the monitoring and replacing of a pressurized oxygen deficient gas containment vessel when said volume of said pressurized oxygen deficient gas is insufficient to ensure application efficiency.

12. The method of claim 8 wherein further comprising the monitoring and charging of a pressurized oxygen deficient gas containment vessel when said volume of said pressurized oxygen deficient gas is insufficient to ensure application efficiency.

13. An oxygen deficient fuel cell produced according to the method of Claim 8.