Abstract: A heat exchanger is formed of a strip of corrugated material that is folded back and forth upon itself to define a stack. Cut pieces of corrugated material are inserted within the folds of the strip, such that the corrugations of the cut pieces are generally perpendicular to the corrugations of the folded strip. A set of duct attachments holds the assembly together, and provides paths for fluid flowing into and out of the exchanger. The ends of the stack, and those parts of the sides that are not spanned by the duct attachments, are sealed with a high-temperature sealant. The sealant is preferably a moldable material that is applied and allowed to harden, and which has a coefficient of thermal expansion that approximates that of the stack. The heat exchanger is easy and inexpensive to manufacture, but is suitable for use in high-temperature applications.

Abstract: A catalytic combustor for a gas turbine includes a stack of metal strips, each strip having an inlet end and an outlet end. The inlet ends of both sides of the strip are uncoated, to limit the temperature and maintain rigidity of the strip at the inlet end. In one embodiment, both sides of the strip have a light-off band, coated with catalyst, and adjacent to the uncoated inlet band. One side of the strip (Side A) also includes at least one combustion band, while the other side (Side B) has no corresponding coated band. The strips are arranged such that Side A of a given strip inside the stack faces Side A of an adjacent strip, and Side B of a strip inside the stack faces Side B of an adjacent strip. The resulting structure prevents overheating of the combustor, maintains its rigidity, and reduces the pressure drop through the combustor.

Abstract: A catalytic combustor for a gas turbine includes a stack of metal strips, each strip having an inlet end and an outlet end. The inlet ends of both sides of the strip are uncoated, to limit the temperature and maintain rigidity of the strip at the inlet end. In one embodiment, both sides of the strip have a light-off band, coated with catalyst, and adjacent to the uncoated inlet band. One side of the strip (Side A) also includes at least one combustion band, while the other side (Side B) has no corresponding coated band. The strips are arranged such that Side A of a given strip inside the stack faces Side A of an adjacent strip, and Side B of a strip inside the stack faces Side B of an adjacent strip. The resulting structure prevents overheating of the combustor, maintains its rigidity, and reduces the pressure drop through the combustor.

Abstract: A multicellular monolith converter body having a plurality of corrugated thin metal sheets or strips in alternating relation with a thin wire mesh or frame, and which monolith has a cell density up to 100 cells per square inch. These monoliths are useful under conditions where back-pressure is a critical factor, e.g., natural draft exhaust applications. These devices may have corrugated thin metal sheets coated with a refractory metal oxide, e.g., alumina, with or without a noble metal catalyst.

Abstract: An exhaust system for an internal combustion engine adapted to correct the problem of pollution occurring at start-up and during at least initial engine running, and characterized by an electrically heatable catalytic converter and, desirably, a separate unheated conventional catalytic converter in tandem relation. The system also provides means for providing electrical power greater than 500 watts for 2 seconds or more whereby the temperature of the catalyst is raised and maintained at least 650 F. An advantage of preferred embodiments is that there is provided a substantially improved means for augmenting conventional catalytic converter exhaust systems for modern requirements by inserting in the exhaust system an electrically heatable catalytic converter for conversion of pollutant material operative prior to, during and after start-up.

Abstract: A metal substrate contains a barrier which functions as an electrical insulator. One can thus use the substrate to make an electrically heated catalytic converter, in which one must electrically isolate a catalyst-bearing strip from adjacent strips. One forms the substrate by first coating the substrate with a thin first layer of alumina washcoat and heating the substrate to a temperature of about 800.degree. to 1000.degree. C. This heating step produces the barrier, which may constitute a spinel. One can then apply a catalyst to the substrate, either by applying one or more secondary layer(s) of washcoat, having greater thickness than the first layer, and impregnating the second layer with the catalyst, or by coating the substrate with a washcoat which already contains the catalyst. Alternatively, one can omit the step of applying the catalyst, and can use the strips to form a heater for a stream of gas. One can use the heater in conjunction with a main catalytic heater, or as a stand-alone heater.

Abstract: There is provided an improved reinforced corrugated thin stainless steel strip in which either or both of the longitudinal edges are overfolded to increase the thickness and stiffness of the foil to better resist the tendency to failure in a severe hot-shake screening test. There is also provided a core and an electrically heatable catalytic converter containing the core for use in the exhaust line of an internal combustion engine.

Abstract: There is provided an improved electrically conductive metal honeycomb body having a plurality of corrugated thin metal strips, which may be heater strips, extending in electrical parallel between otherwise electrically isolated connector plates. The corrugated thin metal strips each have a flat central section. A first group of strips is gathered at their flat middle portions and bent around one of a pair of rigid central posts, and a second group of strips is gathered and bent in the opposite direction about the other of posts. Insulation in the form of a flexible woven ceramic fiber strip isolate the first and second groups from each other and from the central posts. The connector plates define a segmented retainer shell about the body. A battery is connected to the connector plates whereby current flows from one connector plate through corrugated thin metal strips to the other connector plate and back to the battery.

Abstract: There is provided a core element for an electrically heatable catalytic converter, and an electrically heatable catalytic converter containing the same, the core element being characterized by a corrugated thin metal foil strip, preferably herringbone corrugated, and in laminar relationship therewith, a flat thin metal foil strip of either stainless steel or brazing metal, or a combination of both, the flat thin metal foil strip having a width less than the width of the corrugated thin metal foil strip. The strips are then spirally wound, or accordion folded to form a monolith, and suitably connected to a voltage source to supply electrical power to the unit.

Abstract: There is provided an improved core for an electrically heatable catalytic converter, and an electrically heatable catalytic converter containing such core, said core characterized by having a plurality of subcircuits in which the heater strips of thin high temperature resistive metal alloy are in parallel and connected between an outer shell segment and a central structural member, and the plurality of such subcircuits is connected in series, whereby the resistance between the terminals of the electrically heatable catalytic converter is effectively raised.

Abstract: There is provided a core element, especially useful in fabricating an electrically heatable catalytic converter, which element comprises a thin stainless steel strip having an area on at least one surface coated with a masking alloy, especially a nickel-containing brazing alloy, and a contiguous area coated with a refractory metal oxide, e.g., alumina. This structure enables the production of catalytic cores exhibiting minimum voltage drop at the interconnections between foil laminae to be heated electrically.

Abstract: There has thus been provided a highly efficient metal-ceramic catalytic combustor for a gas turbine/catalytic combustor assembly. The catalyst zone is formed of a high temperature resistant metal wire mesh, e.g., palladium coated tungsten or ferritic stainless steel screen, e.g., 40 mesh, which is aluminized with metallic aluminum, and heated to convert the outermost layer of aluminum to aluminum oxide and encourage the diffusion of the inner layer of aluminum into the body of the metal wire, desirably forming a thin metal/aluminum alloy layer. The outer surface because of the Kerkendall Effect is porous and readily accepts and strongly bonds to a metal oxide coat, e.g., a magnesia/alumina, or magnesia/alumina/yttria, or barium oxide/alumina, or barium oxide/alumina/yttria wash coat. There may also be included a catalyst deposited on the ceramic outer coat, e.g., a noble metal catalyst, for enhancement of the combustion of an air/fuel mixture.

Abstract: There is provided an improved electrically heated accordion folded corrugated thin metal catalytic converter for hydrocarbon or alcohol fueled engine exhaust, particularly internal combustion engine exhaust, having a simplified construction and characterized in that the entire corrugated thin metal monolith, or monoliths, serves as a resistance heater to bring the catalyst up to optimum operating temperature quickly and thereby reduce the escape of pollutants into the atmosphere upon start-up, and which does not depend upon conduction as a mdoe of heat transfer to achieve such temperature.

Abstract: There is provided a waste heat recovery system characterized by a boiler assembly including a heat recovery steam generator through which exhaust gas is flowed. The boiler assembly includes a high temperature steam tube heat exchanger, or superheater, and at a location downstream therefrom a water tube boiler. An ammonia gas injector is utilized for injecting ammonia into the exhaust gas stream which injector is located upstream of the superheater and water tube boiler. Finally, there is provided a low temperature selective catalytic reduction unit located downstream of the low temperature water tube boiler or evaporator. This arrangement simplifies retrofitting of existing heat recovery systems.

Abstract: There is provided an improved honeycomb type gas conduit characterized by alternating noncorrugated aluminized ferrous metal foil and corrugated metal foil sheets in contact with each other at the apices or crests of the corrugation. The conduit has an inlet and an outlet for the gas and the honeycomb structure from 20 to 200 cells per square inch. The axes of the cells are parallel throughout their length. A hardened ceramic lip is provided at the leading edge of the cells, and preferably at the leading and trailing edges. When hardened by curing, e.g., with high temperature, the ceramic applied as a slip, forms fillets at the nips between the corrugations and the flat foil sheets, and cements the two together very tightly.

Abstract: There is provided a method for inhibiting corrosion at elevated temperatures of a nonnesting accordion folded or wound corrugated thin metal strip. The strip is corrugated with a longitudinally running series of peaks and valleys by passing the strip through a set of corrugating gears, each of the corrugations including one longitudinally extending displacement deviating from and returning to an imaginary line extending between the longitudinal marginal edges of the strip. The corrugations are characterized further in that the deviation extends in the direction of movement of the strip through the corrugating gears and is first to enter and exit from such gears. This places the maximum of the deviation in compression which has been found to minimize corrosion, e.g., from the pollutants contained in the exhaust from an internal combustion engine.

Abstract: This invention relates to catalyst supports, such as are used in catalytic converters for vehicles, and in other applications, such as diesel particulate traps. The invention discloses a novel composition for a catalyst support, and a method of making it. The support includes a base material, such as a stainless steel. If the base material is a metal, it can be rolled down to the thickness of a foil and then coated with a layer of aluminum. The coating is done by a vapor deposition technique, so that the aluminum coating is thin and substantially uniform. The base material can be almost any substance capable of withstanding the high temperatures expected in the catalytic converter or other application. Because the material is already of foil thickness when it is coated, it is not necessary to select a material which is capable of being rolled down after being coated with aluminum. Thus, the invention makes it possible to use a much wider variety of materials than have been used in the prior art.

Abstract: A method for making a corrugated thin metal strip wherein corrugations are linear and extend obliquely from one longitudinal marginal edge to the opposite longitudinal marginal edge of the strip. The invention involves passing the thin metal strip through corrugating rolls for impressing a series of single apex, V-shaped chevron corrugations into the surface of the metal strip. The rolling of the strip between the helical gears is done in such a way that the apex of the V-shaped chevron is the last portion to leave the corrugating rolls whereby the apex is in tension and enables metal strip to be split into two obliquely corrugated metal strips along the apices of the chevron.

Abstract: A fluid treating device for carrying out chemical and/or physical reactions in a flowing fluid stream in contact with a stationary corrugated thin metal member. The converter comprises a housing and fluid inlet and outlet means associated therewith to define an enclosed housing. The metallic element is an accordion folded thin ribbon having perforations through which fluid may pass through the metal strip for ingress or egress and contact with zig-zag corrugations. Catalysts may be supported on the corrugated metal element whereby the device is especially useful in treating exhaust gases. The device with or without catalyst is useful as a particulate trap, especially for diesel engines.

Abstract: There is provided a process and apparatus for making, preferably continuously, a catalytic converter element or core especially adapted for the treatment of exhaust from an internal combustion engine, whether spark or compression ignited. The converter element may be a fan-folded or accordion folded thin metal strip or a spirally wound element which carries strongly adhered to the surface thereof a catalyst, e.g. a noble or precious metal catalyst such as platinum and/or palladium and/or rhodium. The metal strip entering the process is an aluminum coated ferritic ribbon between 0.001 and 0.003 inches thick, and 1 inch to 30 inches wide. The strip is preferably annealed and perforated at predetermined intervals. Thereafter, the strip is corrugated and given a washcoat of a refractory metal oxide which is calcined onto the surface. One or more precious metal catalysts are supplied and dried.