Patents by Inventor Karl M. Prewo
Karl M. Prewo has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 4913953Abstract: A chopped fiber reinforced glass or glass-ceramic matrix integral stgructure having no bond lines. The structure comprises a face plate, a back plate, and a grid array of chamber walls. The face plate connects to the back plate through the chamber walls forming a grid array of chambers. The back plate has an array of apertures that lead to the chambers. The structure is fabricated by disposing at least two mold inserts in a mold housing having a bottom and sides. The mold inserts are in contact and in an array that follows the surface contours of the mold. The mold inserts and mold insert array is not capable of lateral movement. Heated chopped glass or glass ceramic impregnated fibers are displaced into the mold under pressure to form a composite. The composite is cooled and the mold inserts are removed by chemical dissolution.Type: GrantFiled: December 23, 1988Date of Patent: April 3, 1990Assignee: United Technologies CorporationInventors: Karl M. Prewo, Eric Minford
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Patent number: 4911990Abstract: A microstructurally toughened metallic article is disclosed. The article includes discrete metal regions which are enclosed within and separated from each other by a network of metal. The regions are bonded to the network to form stable interfacial boundaries. The article exhibits high impact resistance. The process for making the article is also disclosed. The process includes positioning a plurality of structural elements within a container to define one or more void spaces within the container, introducing a quantity of metallic particles into the void spaces, and then consolidating the container, structural elements, and particles to form the microstructurally toughened article.Type: GrantFiled: February 5, 1988Date of Patent: March 27, 1990Assignee: United Technologies CorporationInventors: Karl M. Prewo, Vincent C. Nardone, James R. Strife
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Patent number: 4885212Abstract: A microstructurally toughened ceramic-particle-reinforced metal-matrix composite article is disclosed. The article exhibits a complex microstructure. The article exhibits high tensile strength, high elastic modulus and high impact resistance. A process for making the article is also disclosed. The process includes positioning structural elements within a metallic container to define one or more void spaces within the container, introducing a quantity of metallic particles or of a particular mixture of metallic particles and ceramic particles into the void spaces, and consolidating the container, structural elements and particles to form the microstructurally toughened composite article.Type: GrantFiled: February 5, 1988Date of Patent: December 5, 1989Assignee: United Technologies CorporationInventors: Karl M. Prewo, Vincent C. Nardone, James R. Strife
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Patent number: 4870827Abstract: A durable low weight compressor having improved performance is disclosed. The compressor includes a fiber reinforced resin matrix composite housing and a fiber reinforced glass marix composite compression chamber liner. An air conditioner including an improved compressor is also disclosed.Type: GrantFiled: August 12, 1987Date of Patent: October 3, 1989Assignee: United TechnologiesInventors: David J. McFarlin, Antonio B. Caruolo, Eric Minford, Karl M. Prewo
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Patent number: 4857485Abstract: A silicon carbide fiber reinforced glass-ceramic matrix composite article is disclosed. The matrix is a lithium alumino silicate glass-ceramic composition which may include from 1 to 5 weight percent B.sub.2 O.sub.3. The fiber reinforced glass-ceramic matrix composite article exhibits both high flexural strength at elevated temperatures and oxidative stability at elevated temperatures in an oxidizing environment.Type: GrantFiled: October 14, 1987Date of Patent: August 15, 1989Assignee: United Technologies CorporationInventors: John J. Brennan, George K. Layden, Karl M. Prewo
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Patent number: 4857093Abstract: A chopped fiber reinforced glass or glass-ceramic matrix integral structure having no bond lines. The structure comprises a face plate, a back plate, and a grid array of chamber walls. The face plate connects to the back plate through the chamber walls forming a grid array of chambers. The back plate has an array of apertures that lead to the chambers. The structure is fabricated by disposing at least two mold inserts in a mold housing having a bottom and sides. The mold inserts are in contact and in an array that follows the surface contours of the mold. The mold inserts and mold insert array is not capable of lateral movement. Heated chopped glass or glass ceramic impregnated fibers are displaced into the mold under pressure to form a composite. The composite is cooled and the mold inserts are removed by chemical dissolution.Type: GrantFiled: November 23, 1987Date of Patent: August 15, 1989Assignee: United Technologies CorporationInventors: Karl M. Prewo, Eric Minford
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Patent number: 4808485Abstract: A microstructurally toughened ceramic-particle-reinforced metal-matrix composite article is disclosed. The article includes discrete regions of ceramic-particulate-reinforced metal matrix which enclosed within and separated from each other by a network of unreinforced metal. The article exhibits high tensile strength, high elastic modulus and high impact resistance. A process for making the article is also disclosed. The process includes positioning structural elements within a metallic container to define a plurality of discrete void spaces within the container, introducing a quantity of metallic particles or of a particulate mixture of metallic particles and ceramic particles into the void spaces, and consolidating the container, structural elements and particles to form the microstructurally toughened composite article.Type: GrantFiled: February 5, 1988Date of Patent: February 28, 1989Assignee: United Technologies CorporationInventors: Karl M. Prewo, Vincent C. Nardone, James R. Strife
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Patent number: 4808076Abstract: A rotor for a gas turbine engine is disclosed. The rotor comprises a glass or glass ceramic matrix reinforced with silicon carbide yarn fiber reinforcement and with silicon carbide yarn reinforcement. The local volume fraction of silicon carbide monofilament increases with increasing radial distance from the inner diameter of the rotor. The rotor exhibits high hoop strength, high oxidation resistance at elevated temperatures and nonuniform elastic modulus which increases with increasing radial distance from the inner diameter of the rotor.Type: GrantFiled: December 15, 1987Date of Patent: February 28, 1989Assignee: United Technologies CorporationInventors: David C. Jarmon, Karl M. Prewo
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Patent number: 4780432Abstract: A method for manufacturing a discontinuous fiber reinforced glass matrix composites by injection molding using an injection nozzle that separates substantially all of a multifilament yarn into individual fibers resulting in a composite having greater crack resistance. The method comprises impregnating continuous filament yarn with glass matrix powders comprising glass, glass-ceramic powders or a mixture thereof. The impregnated multifilament yarn is chopped into discontinuous lengths and exposed to a temperature sufficient so that the matrix material softens. Pressure is applied to the heated impregnated multifilament yarn sufficient to displace the yarn into a mold through an injection nozzle contoured such that sufficient die-wall shear forces are generated to separate substantially all of the multifilament yarn into individual filaments. A mold pressure is maintained sufficient to prevent relaxation of the composite until the strain point of the glass is reached.Type: GrantFiled: September 2, 1986Date of Patent: October 25, 1988Assignee: United Technologies CorporationInventors: Eric Minford, Karl M. Prewo, David J. McFarlin, Antonio B. Carulo
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Patent number: 4766096Abstract: An improved composite material consisting of silicon nitride whiskers uniformly dispersed through a glass matrix and a method for making the composite which comprises the step of dispersing the whiskers in a suitable liquid and separating off the fines and, optionally, the step of treating the dispersed whiskers with HF.Type: GrantFiled: February 24, 1987Date of Patent: August 23, 1988Assignee: The United States of America as represented by the Secretary of the Air ForceInventors: George K. Layden, Karl M. Prewo
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Patent number: 4738902Abstract: High strength, fracture tough, high temperature oxidatively stable, gas turbine engine core engine components are described made of silicon carbide fiber reinforced ceramic matrix or silicon carbide fiber reinforced glass matrix material. A gas turbine engine containing core engine components as above described is also disclosed.Type: GrantFiled: February 19, 1986Date of Patent: April 19, 1988Assignee: United Technologies CorporationInventors: Karl M. Prewo, John J. Brennan
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Patent number: 4666645Abstract: The present invention discloses a process of forming glass, glass-ceramic or ceramic matrix, fiber reinforced composite articles. The method comprises preparing both the matrix and the reinforcement into fibers, which are then chopped into relatively short lengths. These chopped fibers are then formed into hybrid felt papers comprising a mixture of both reinforcing fibers and matrix fibers. These felt papers are then cut into preforms and stacked one on top of the other to form a lay-up. The lay-up is then placed in a die and densified to form the composite article.Type: GrantFiled: April 20, 1984Date of Patent: May 19, 1987Assignee: United Technologies CorporationInventors: Karl M. Prewo, George K. Layden
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Patent number: 4664731Abstract: A method of making fiber reinforced glass composite articles utilizes preregnated preforms which are bound with a temporary plastic binder. The binder is removed in a gradient oven and the frit or preform is drawn through a pultrusion die assembly heated to the degree necessary to render the frit workable. Deformation in the heated die assembly is maintained during cooling, resulting in a formed glass composite article.Type: GrantFiled: January 7, 1985Date of Patent: May 12, 1987Assignee: The United States of America as represented by the Secretary of the NavyInventors: George K. Layden, Karl M. Prewo
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Patent number: 4626461Abstract: High strength, fracture tough, high temperature oxidatively stable, gas turbine engine core engine components are described made of silicon carbide fiber reinforced ceramic matrix or silicon carbide fiber reinforced glass matrix material. A gas turbine engine containing core engine components as above described is also disclosed.Type: GrantFiled: January 18, 1983Date of Patent: December 2, 1986Assignee: United Technologies CorporationInventors: Karl M. Prewo, John J. Brennan
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Patent number: 4623228Abstract: An improved mirror substrate, that is particularly adapted for use as a laser mirror, has significantly improved transverse strength and polishability and a method of making the same. The composite comprises graphite fibers coated with an oxidized silicon carbide layer. The coated fibers alternate with layers of glass to form a composite, preferably having a central plane of symmetry across its central plane.Type: GrantFiled: October 25, 1984Date of Patent: November 18, 1986Assignee: United Technologies CorporationInventors: Francis S. Galasso, Karl M. Prewo, Richard D. Veltri
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Patent number: 4613473Abstract: The present invention discloses a method of making fiber reinforced glass, glass-ceramic or ceramic matrix composite articles. The method comprises forming the matrix material into fibers and then into yarn which is woven or knitted into cloth. The matrix cloth is then cut into preformed shapes and interleaved with preformed pieces of fabric which have been woven or knitted from yarn containing the fiber reinforcement. The interleaved preformed structure is then placed in a die and densified under pressure and temperature to form the composite article. Also disclosed is a method wherein the yarn of reinforcing fiber and matrix fibers is woven or knitted together to form a hybrid cloth. This hybrid cloth is then cut into predetermined forms and placed in a die and densified under heat and pressure to form the composite article.Type: GrantFiled: April 20, 1984Date of Patent: September 23, 1986Assignee: United Technologies CorporationInventors: George K. Layden, Karl M. Prewo
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Patent number: 4581053Abstract: A method of producing fiber reinforced glass composites of complex shapes (e.g. having curved portions such as cylindrical) is disclosed. A continuous length of fiber, such as silicon carbide, is passed through a slurry of glass powder and a carrier liquid containing a polymeric binder to impregnate the fiber. The impregnated fiber is next dried and woven into a predetermined structural shape. Plies of the woven fiber cut to near net shape may also be stacked into the desired shape. The thus laid fibers are hot pressed into a fiber reinforced glass matrix composite article having glass matrix distributed substantially uniformly therethrough and multiaxial strength in at least three mutually exclusive perpendicular directions.Type: GrantFiled: May 25, 1982Date of Patent: April 8, 1986Assignee: United Technologies CorporationInventors: Karl M. Prewo, George K. Layden
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Patent number: 4464192Abstract: A method of making complex shaped (e.g. having curved surfaces or walls) fiber reinforced glass matrix composites by injection molding is described. The injection molding can take place by heating and injecting a mixture of glass powder and chopped fibers or whiskers directly into the mold, or a billet of glass matrix material containing the chopped fibers or whiskers made with a density approximately equal to the density of the final composite can be prepared first. In one embodiment the billet is formed by admixing a polymeric binder, glass powder, and a carrier liquid with the reinforcing fibers, drying the mixture, cold pressing the mixture to less than its original volume, and hot pressing to the density desired in the final product. Either the glass powder-chopped fiber or whisker combination or the formed billet is next placed in the injection molding apparatus where it is heated at least to the softening point of the matrix glass and injected into the predetermined mold shape.Type: GrantFiled: May 25, 1982Date of Patent: August 7, 1984Assignee: United Technologies CorporationInventors: George K. Layden, Karl M. Prewo
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Patent number: 4451118Abstract: A laser mirror is described having a base section, a backing section, and a laser radiation reflecting surface. The base section and backing section are formed of graphite fiber reinforced glass. The fibers in the base section are oriented in a plane parallel to the laser radiation reflecting surface. The fibers in the backing section are oriented in a plane perpendicular to the radii of the reflecting surface. Based on the materials employed and the orientation of the fibers, a laser mirror with improved thermal distortion properties results.Type: GrantFiled: December 23, 1980Date of Patent: May 29, 1984Assignee: United Technologies CorporationInventors: Robert K. Stalcup, Warren R. Sigman, Karl M. Prewo
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Patent number: H347Abstract: A hot pressed, fiber reinforced matrix composite consisting essentially of a plurality of alumina fibers in a lithium aluminosilicate glass matrix. The composite is fabricated by hot pressing alumina fibers impregnated with lithium aluminosilicate glass frit and heat treating the hot pressed composite at an elevated temperature for 12 to 36 hours.Type: GrantFiled: July 8, 1986Date of Patent: October 6, 1987Assignee: The United States of America as represented by the Secretary of the Air ForceInventors: George K. Layden, Karl M. Prewo