Electric heating – Metal heating – By arc
Reexamination Certificate
1999-12-08
2001-12-18
Shaw, Clifford C. (Department: 1725)
Electric heating
Metal heating
By arc
C219S074000, C219S130100, C429S010000
Reexamination Certificate
active
06331694
ABSTRACT:
The invention relates to the art of welding with an electric arc and more particularly to an arc welder that is powered by a fuel efficient and portable power source, and even more particularly to an arc welder that is at least partially powered by a fuel cell.
INCORPORATION BY REFERENCE
The present invention incorporates the use of fuel cells of the general type described in United States Letters Patent Nos. 5,599,638; 5,656,388; 5,773,162; 5,795,496; 5,888,665; and 5,928,806; and PCT Patent Application Nos. WO 98/22989; WO 98/45694; WO 99/16137; and WO 99/39841. These patents and patent applications are also incorporated herein to describe the manufacture of the fuel cell components and operation of such fuel cells. United States Letters Pat. Nos. 4,861,965; 4,972,064; 5,148,001; and 5,961,863 are also incorporated herein to describe a few of the welders that can be used with a fuel cell.
BACKGROUND OF THE INVENTION
This invention relates to the field of arc welding, and more particularly to an improved arc welder that incorporates a fuel cell as an at least partial source of power for the arc welder.
Arc welders are typically powered by plugging the arc welding into an electrical outlet or having the arc welder equipped with a gas powered electric generator. Arc welders that are designed to receive power from an electric outlet are limited to use in a location that has an electric outlet which is rated to supply the needed current for operation of the arc welder. Operators of such arc welders need extension cords to increase the mobility of such arc welders. When the arc welder is used in a remote location or in a location that is not readily accessible to a power outlet or a power outlet having a needed current rating, the arc welder must be equipped with its own power source, such as a gas electric generator, to supply the required current to the arc welder. The gas generator is typically designed to be powered by a standard petroleum fuel source such as gasoline. In many operational environments, these two power source arrangements for arc welders are sufficient to satisfy the power demands of the arc welder.
Arc welders that are used in remote locations that are partially or totally enclosed or are not well ventilated may require special equipment during the welding operation. In such locations, a gas powered electric generator is used to supply power to the arc welder. During the operation of the gas powered generator, exhaust fumes are produced which can be unhealthy if breathed in sufficient concentrations. In additional, the gas powered generator produces noise during operation. Such noise could cause temporary hearing loss when operating the arc welder in a small enclosed environment for long periods of time. In addition to these operator health concerns, the operation of the gas powered electric generator produces pollutants which can be harmful and/or adversely affect the environment. These pollutants include noise pollution and combustion products from the combustion of fuel by the gas powered generator. Pollution concerns also exist for electric powered arc welders since the electricity is typically generated by coal burning generators and atomic power plants, both of which create their own environmental hazards. In addition to the pollution concerns of the energy sources, the cost of the energy continues to rise. As oil supplies and coal supplies continue to deplete worldwide, the cost of gasoline and electricity generated by coal burning generators will continue their unabated rise in cost. Rising energy costs generally slow or stunt growth in the industrial sectors.
Although these problems have existed for some time, there has heretofore been no viable alternative to gas powered electric generators for arc welders or arc welders powered by an electric outlet source. Battery powered arc welders are very bulky and have a limited life. Furthermore, once the battery has been discharged, the battery must be disposed of which is in-of-itself an environmental concern. In addition, many batteries require concentrated acids which can be harmful if such acid fumes are breathed in or if the acid contacts human skin. The acid is also an environmental pollutant requiring special and costly disposal. Solar power is another power source which is not feasible for use with an electric arc welder. The size of the solar panels necessary to generate the required amount of power are too large to use, especially in small environments. Furthermore, the solar panels require sunlight, thus on cloudy days or in enclosed environments, the solar battery will not produce the needed electric power. Solar power panels are also very expensive thereby making them cost prohibitive for use with arc welders. Wind powered generators are also not feasible due to their bulky construction and need for a consistent wind source. The bulkiness of batteries, solar panels, and wind powered generators compound the size problems of the arc welder. The electric circuitry in the welder is limited to a certain size by the power demands of the arc welder. Arc welders which require shielding gas must include bulky canisters to supply the shielding gas. The combination of bulky shielding gas canisters with a bulky power source would make the arc welder unwieldy for use in many environments.
In view of the problems associated with alternative power sources for electric arc welders, there is a need for an improved power source that is environmentally friendly, can be safely use in a wide variety of locations, and is simple and safe to operate.
SUMMARY OF THE INVENTION
The present invention relates to a method and apparatus of arc welding together metal plates, and more particularly a method and apparatus for arc welding that incorporate a fuel cell as an energy source to totally or partially power the arc welder.
In accordance with the preferred embodiment of the present invention, there is provided a fuel cell power supply with a positive and negative terminal, a welding current circuit which applies a welding current across a welding electrode and a workpiece. The fuel cell is an electrochemical cell in which a free energy change resulting from a fuel oxidation reaction is converted into electrical energy. In one embodiment, an organic/air fuel cell is used to oxidize an organic fuel to carbon dioxide at an anode while air or oxygen is reduced to water at a cathode. Fuel cells employing organic fuels are extremely attractive because of the high specific energy of the organic fuels. In another embodiment, the fuel cell is an “indirect” or “reformer” fuel cell or a “direct oxidation” fuel cell. In an indirect fuel cell, the fuel is catalytically reformed and processed. For organic fuels, the fuel is catalytically reformed and processed into carbon monoxide-free hydrogen, with the hydrogen so obtained oxidized at the anode of the fuel cell. In a direct oxidation fuel cell, the fuel is directly fed into the fuel cell without any previous chemical modification where the fuel is oxidized at the anode. Direct oxidation fuel cells do not require a fuel processing stage. As a result, direct oxidation fuel cells are generally less complicated and are smaller in size than indirect fuel cells.
In accordance with another aspect of the present invention, the fuel cell includes high-surface-area electro-catalytic anodes and/or cathodes. In one embodiment, the fuel cell anode and/or cathode fabrication includes a high surface-area carbon-supported metal powder. In one aspect of this embodiment, alloy powder combined with a TEFLON binder is applied to a carbon fiber-based support to yield a gas diffusion anode and/or cathode. In another embodiment, the anode and/or cathode is used for gas and/or liquid feeds. In still another embodiment, the anode and/or cathode is very porous to allow for proper wetting of the pores.
In accordance with still another embodiment of the present invention, the anode and/or cathode of the fuel cell is coated by a substance that improves the wetting properties of the electrode. In accordance with
Lincoln Global Inc.
Shaw Clifford C.
Vickers Daniels & Young
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