Combustion – Fuel disperser installed in furnace – Disperser feeds into permeable mass – e.g. – checkerwork – etc.
Reexamination Certificate
1999-07-06
2001-02-27
Yeung, James C. (Department: 3743)
Combustion
Fuel disperser installed in furnace
Disperser feeds into permeable mass, e.g., checkerwork, etc.
C431S268000, C431S328000, C422S177000, C422S198000, C502S527230
Reexamination Certificate
active
06193501
ABSTRACT:
FIELD OF THE INVENTION
This invention generally concerns the field of micro-scale power sources. More specifically, the invention concerns a microcombuster having a submillimeter combustion chamber which will neither thermally quench a flame nor chemically quench a flame, so that spontaneous internal combustion can be sustained.
BACKGROUND OF THE INVENTION
The quenching effect of submillimetric spaces has been known and used for many years. Sir Humphrey Davy patented the explosion proof lamp in 1812. He showed with his invention that combustion was completely quenched if a flame had to pass through a mesh of sub-millimeter critical dimensions. Other scientists throughout the 1800's and early 1900's separately proposed mechanisms and experimental verification that combustion is quenched within millimeters of surfaces. At that time, this was an important discovery since it allowed for safety mechanisms on lamps and other devices used by miners. By forcing a flame to come into contact with a sub-millimeter hole, the flame would be quenched and large explosions could be avoided. This same concept is used extensively in flame arresters today.
Recently scientists have become interested in microcombustion as a compact and efficient power source. It is recognized that so-called microcombustors would be especially useful in operating microelectromechanical systems, or MEMS. MEMS have wide ranging potential use in various fields such as military sensing operations and medical devices.
To date, batteries have been the mainstays for supplying power for micro-scale systems and MEMS devices. These battery packs, however, are much larger than the micro-electronics and communication packages combined. Also, the battery is inefficient, in that it must be recharged frequently. Therefore, there is a need for alternative, low-cost methods of generating continuous power sources for MEMS.
Any number of other devices would similarly benefit from a microcombustion power source. Since combustion produces the highest power per unit of weight of volume of all methods of generating and supplying power excepting nuclear energy, it has become an identified source as a potential replacement for batteries, typically used in any number of portable devices, e.g., computers, cell phones, flashlights. Also, microcombustors can be used for heat sources for micro-to miniature chemical reactors, and for micro-to miniature internal and external combustion engines. However, as discussed above, it is well known that combustion does not occur on the sub-millimeter level due to the quenching of the flame. Therefore, researchers have been impeded by their inability to sustain combustion at submillimetric dimensions.
Therefore, there is a need for a microcombuster which is submillimetric in critical dimension. Also, there is a need for a microcombustor which is self-sustaining so it can be used for long periods of time without need of recharging.
Accordingly, it is an object of the present invention to provide a new and improved microcombustor which sustains combustion at submillimetric dimensions.
Another object of the present invention is to provide an improved microcombustor which can propagate a flame through a hole with a diameter which is submillimetric.
Another object of the present invention is to provide a new and improved microcombustor which is self-sustaining and can provide power for long periods of time without recharging.
SUMMARY OF THE INVENTION
These and other needs are met or exceeded by the present microcombuster. Basically, the invention prevents quenching at submillimetric dimensions to enable self-sustained combustion on a microscale. The invention utilizes a combustor that is sub-millimetric in critical dimensions, which are determined by the distance the wall acts on the gases above the surface, and houses a combustion chamber. The walls have chemical characteristics which prevent chemical quenching of the flame at the walls. In a preferred embodiment, the combustion chamber utilizes catalysts to get the reactants hot, ignited and burning. Reactants are introduced into the combustion chamber through inlets. The preferred chamber further utilizes a structure and design which allow the walls to become heated along with the reactants. Since the walls stay hot, thermal quenching of a flame that was created can be avoided.
REFERENCES:
patent: 4916904 (1990-04-01), Ramsaier et al.
patent: 5403184 (1995-04-01), Hosaka et al.
patent: 5932940 (1999-08-01), Epstein et al.
patent: 43737 (1979-12-01), None
A. Mehra, I.A. Waitz, “Development of a Hydrogen Combustor for a Microfabricated Gas Turbine Engine”, presented at Solid-State Sensor and Actuator Workshop, Hilton Head Island, South Carolina, Jun. 8-11, 1998.
R.I. Masel, “Principles of Adsorption and Reaction on Solid Surfaces”, J. Wiley & Sons, New York, 1996, pp. 361-370.
S. Kondo, S. Horiguchi, M. Iwasaka, K. Tokuhashi, H. Nagai, “Effect of Pressure and Oxygen Concentration on Quenching Distances of Flammable Gases”, Nippon Kagaku Kaishi 7, 1992, pp. 788-792.
S. Ono, Y. Wakuri, “An Experimental Study on the Quenching of Flame by Narrow Cylindrical Passage”,Bulletin of the JSME, vol. 20, No. 147, Sep. 1977, pp. 1191-1198.
J.R. Price, M. Van Roode, “Corrosion resistant Coatings for Silicon Carbide Heat Exchanger Tubes”,Ceramic Thin and Thick Films, V. Basavaraj, Ed. American Ceramic Society, Westerville, OH, pp. 169-188 (1990).
H. Davy,Philosophical Transactions of the Royal Society of London, 1817, pp. 45-85.
Y. Kadioglu, H. Sehitoglu, “Thermomechanical and Isothermal Fatigue Behavior of Bare and Coated Superalloys”,ASME Journal of Engineering for Materials and Technology, vol. 118, Jan. 1996, pp. 94-102.
H. Sehitoglu, “Thermal and Thermomechanical Fatigue of Structural Alloys”,ASM Handbook on Fatigue and Fracture, vol. 19, pp. 527-556.
O.M. Akselsen, “Review-Diffusion Bonding of Ceramics”,Journal of Material Science, vol. 27, 1992, pp. 569-579.
M.G. Nicholas, R.M. Crispin, “Diffusion Bonding Ceramics with Ductile Interlayers”,Science of Ceramics, vol. 14, 1988, pp. 539-544.
M.A. Shannon, R.I. Masel, slide presentation entitled “Power Generation Based on Microscale Combustion”, given on Jul. 8, 1999, at a Principle Investigators meeting for the DARPA ETO program.
M.A. Shannmon, R.I. Masel, slide presentation entitled “Micro-Engines Based on Combustion at the Micro-Scale”, given on Jan. 15, 1999, at a Principle Investigators meeting for the DARPA ETO program in Baton Rouge, LA.
Masel Richard I.
Shannon Mark A.
Greer Burns & Crain Ltd.
The Board of Trustees of the University of Illinois
Yeung James C.
LandOfFree
Microcombustor having submillimeter critical dimensions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Microcombustor having submillimeter critical dimensions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microcombustor having submillimeter critical dimensions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2564513