Abstract: An example method includes combining an interlayer and a carbon fiber fabric, wherein the interlayer comprises a highly oriented milled carbon fiber ply comprising a plurality of out-of-plane carbon fibers. The method further includes winding the interlayer and the carbon fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

Abstract: An example method includes forming an interlayer on a carbon fiber fabric to form a composite fiber fabric. The interlayer comprises a binder. The method further includes winding the composite fiber fabric around a core to form a composite fiber preform comprising a plurality of layers defining an annulus extending along a central axis. The method further includes densifying the composite fiber preform.

Abstract: A carbon-carbon composite preform including a plurality of layers including carbon fibers or carbon-precursor fibers, the layers include a first exterior layer defining a first major surface, a second exterior layer defining a second major surface, and at least one interior layer disposed between the first exterior layer and the second exterior layer, the at least one interior layer having a peripheral region that forms a portion of an outer surface of the preform. The preform includes needled fibers, where at least some needled fibers extend through two or more layers. The preform has an exterior region and a core region, where the exterior region includes at least the peripheral region of at least one interior layer. The needled fibers define a first needled fiber number density (NFND) in the exterior region and a second greater NFND in at least a portion of the core region.

Abstract: A carbon-carbon composite preform including a plurality of layers including carbon fibers or carbon-precursor fibers, the layers include a first exterior layer defining a first major surface, a second exterior layer defining a second major surface, and at least one interior layer disposed between the first exterior layer and the second exterior layer, the at least one interior layer having a peripheral region that forms a portion of an outer surface of the preform. The preform includes needled fibers, where at least some needled fibers extend through two or more layers. The preform has an exterior region and a core region, where the exterior region includes at least the peripheral region of at least one interior layer. The needled fibers define a first needled fiber number density (NFND) in the exterior region and a second greater NFND in at least a portion of the core region.

Abstract: A pitch densification apparatus may be used to form a carbon-carbon composite material. The apparatus may be used to compress a carbon fiber material, and, thereafter, pitch densify the carbon fiber material. The compression and pitch densification of the carbon fiber material may be carried out within the same mold cavity of the pitch densification apparatus. In one example, an apparatus may comprise a mold defining a mold cavity that is configured to receive a material to be densified. The mold cavity is configured to be adjusted from a first volume to a second volume less than the first volume to compress the material in the mold cavity. The example apparatus may further comprise a gas source configured to apply a gas pressure in the mold cavity to force pitch into the material in the mold cavity to densify the material, and a vacuum source configured to create a vacuum pressure in the mold cavity at least prior to the application of the gas pressure.

Abstract: Carbon-carbon composites made by needling together woven or nonwoven fabric made from carbon-containing fibers followed by carbonizing the fabric preforms are described. The carbon fiber preforms can be needled either in a carbonized or in an uncarbonized state. The uncarbonized fiber preforms would go through a carbonization/heat-treat step following the needling process. Final preform thickness and fiber volume is also controlled at carbonization, for instance by varying the level of pressure applied to the preforms during carbonization. For example, the preforms may be unconstrained during carbonization (i.e., no pressure is applied to them) or the preforms may be constrained during carbonization, typically by means for applying pressure (e.g., weight placed on top of the preforms).

Abstract: A pitch densification apparatus may be used to form a carbon-carbon composite material. The apparatus may be used to compress a carbon fiber material, and, thereafter, pitch densify the carbon fiber material. The compression and pitch densification of the carbon fiber material may be carried out within the same mold cavity of the pitch densification apparatus. In one example, an apparatus may comprise a mold defining a mold cavity that is configured to receive a material to be densified. The mold cavity is configured to be adjusted from a first volume to a second volume less than the first volume to compress the material in the mold cavity. The example apparatus may further comprise a gas source configured to apply a gas pressure in the mold cavity to force pitch into the material in the mold cavity to densify the material, and a vacuum source configured to create a vacuum pressure in the mold cavity at least prior to the application of the gas pressure.

Abstract: A pitch densification apparatus may be used to form a carbon-carbon composite material. The apparatus may be used to compress a carbon fiber material, and, thereafter, pitch densify the carbon fiber material. The compression and pitch densification of the carbon fiber material may be carried out within the same mold cavity of the pitch densification apparatus. In one example, an apparatus may comprise a mold defining a mold cavity that is configured to receive a material to be densified. The mold cavity is configured to be adjusted from a first volume to a second volume less than the first volume to compress the material in the mold cavity. The example apparatus may further comprise a gas source configured to apply a gas pressure in the mold cavity to force pitch into the material in the mold cavity to densify the material, and a vacuum source configured to create a vacuum pressure in the mold cavity at least prior to the application of the gas pressure.

Abstract: A pump end assembly has a centrifugal pump and a motor separated by a chamber. The chamber contains a thrust bearing as well as an intake for the pump. Fluid flowing into the intake flows through the thrust chamber and to the inlet of the pump. Some of the fluid also flows through the thrust bearing for lubricating the thrust bearing.

Abstract: Carbon-carbon composites made by needling together woven or nonwoven fabric made from carbon-containing fibers followed by carbonizing the fabric preforms. The carbon fiber preforms can be needled either in a carbonized or in an uncarbonized state. The un-carbonized fiber preforms would go through a carbonization/heat-treat step following the needling process. Final preform thickness and fiber volume is also controlled at carbonization, for instance by varying the level of pressure applied to the preforms during carbonization. Thus, the preforms may be unconstrained during carbonization (i.e., no pressure is applied to them). Or the preforms may be constrained during carbonization, typically by means of applying pressure (e.g., weight placed on top of the preforms). The preforms are then infiltrated via CVD/CVI processing in order to increase their density, resulting in a carbon-carbon composite which is suitable for use as, for instance, a brake disc or pad in aircraft and automotive brake systems.

Abstract: This invention generally pertains to self propagating high temperature synthesis or combustion synthesis as a way of bonding materials. The present invention provides methods and an apparatus for bonding, preferably carbon-carbon composite materials, by combustion synthesis. Generally, the invention involves providing at least two carbon-carbon composite parts to be bonded and interspersing a combustion synthesis material in between the parts with each part in contact with the combustion synthesis material. The combustion synthesis material is then ignited, which initiates the combustion synthesis reaction. Typically, a ceramic material is formed which immediately freezes, bonding the parts together.

Abstract: A pump end assembly has a centrifugal pump and a motor separated by a chamber. The chamber contains a thrust bearing as well as an intake for the pump. Fluid flowing into the intake flows through the thrust chamber and to the inlet of the pump. Some of the fluid also flows through the thrust bearing for lubricating the thrust bearing.

Abstract: A centrifugal pump has impellers for pumping low flow, high viscous materials. The impellers have high exit angles greater than 30 degrees and preferably greater than 50 degrees. The impellers and diffusers have specific geometry that varies with viscosity. The pump has zones of impellers and diffusers with the exit angles and geometry in the zones differing from the other zones. The exit angles decrease and geometry varies in a downstream direction to account for a lower viscosity occurring due to heat being generated in the pump. One design employs small diameter impellers and high rotational speeds.

Abstract: This invention generally pertains to self propagating high temperature synthesis or combustion synthesis as a way of bonding materials. The present invention provides methods and an apparatus for bonding, preferably carbon-carbon composite materials, by combustion synthesis. Generally, the invention involves providing at least two carbon-carbon composite parts to be bonded and interspersing a combustion synthesis material in between the parts with each part in contact with the combustion synthesis material. The combustion synthesis material is then ignited, which initiates the combustion synthesis reaction. Typically, a ceramic material is formed which immediately freezes, bonding the parts together.

Abstract: Carbon-carbon composite material article and method of manufacturing it. The carbon-carbon composite material comprises a carbonized woven or nonwoven fabric-based preform which is subjected to rapid densification, e.g. using a resin transfer molding process, and which may subsequently be infiltrated with a ceramic additive solution in order to improve wear and friction properties. The method comprises densifying the preform and subsequently adding a ceramic additive to it to infiltrate the material with the additive and enhance the properties of the final product.

Abstract: A centrifugal pump has impellers for pumping low flow, high viscous materials. The impellers have high exit angles greater than 30 degrees and preferably greater than 50 degrees. The impellers and diffusers have specific geometry that varies with viscosity. The pump has zones of impellers and diffusers with the exit angles and geometry in the zones differing from the other zones. The exit angles decrease and geometry varies in a downstream direction to account for a lower viscosity occurring due to heat being generated in the pump. One design employs small diameter impellers and high rotational speeds.

Abstract: Carbon fiber brake preforms (20), specifically, annular discs built up of fabric arc segments (21) composed of continuous fibers (25) and staple fibers (26). Most of the continuous fibers (25) in the fabric segments (21) are arranged to be located within 60° of radially from th e inner diameter to the outer diameter of the annular disc (20). The fabric arc segments have substantially all of their continuous fibers oriented in the radial direction and parallel to the segment arc bisector, or the segments are arranged in alternating layers in which, respectively, half the continuous fibers are oriented at a +45 degree angle with respect to the segment arc bisector and half the continuous fibers are oriented at a −45 degree angle with respect thereto.

Abstract: Carbon fiber brake preforms (20), specifically, annular discs built up of fabric arc segments (21) composed of continuous fibers (25) and staple fibers (26). Most of the continuous fibers (25) in the fabric segments (21) are arranged to be located within 60° of radially from the inner diameter to the outer diameter of the annular disc (20). The fabric arc segments have substantially all of their continuous fibers oriented in the radial direction and parallel to the segment arc bisector, or the segments are arranged in alternating layers in which, respectively, half the continuous fibers are oriented at a +45 degree angle with respect to the segment arc bisector and half the continuous fibers are oriented at a −45 degree angle with respect thereto.

Abstract: A centrifugal pump has impellers for pumping low flow, high viscous materials. The impellers have high exit angles greater than 30 degrees and preferably greater than 50 degrees. The impellers and diffusers have specific geometry that varies with viscosity. The pump has zones of impellers and diffusers with the exit angles and geometry in the zones differing from the other zones. The exit angles decrease and geometry varies in a downstream direction to account for a lower viscosity occurring due to heat being generated in the pump. One design employs small diameter impellers and high rotational speeds.

Abstract: Carbon fiber brake preforms (20), specifically, annular discs built up of fabric arc segments (21) composed of continuous fibers (25) and staple fibers (26). Most of the continuous fibers (25) in the fabric segments (21) are arranged to be located within 60° of radially from the inner diameter to the outer diameter of the annular disc (20). The fabric arc segments have substantially all of their continuous fibers oriented in the radial direction and parallel to the segment arc bisector, or the segments are arranged in alternating layers in which, respectively, half the continuous fibers are oriented at a +45 degree angle with respect to the segment arc bisector and half the continuous fibers are oriented at a −45 degree angle with respect thereto.