A pipe element suitable for use in a fuel system of an aircraft comprises an inner pipe and an outer pipe sealingly surrounding the inner pipe and connected to the inner pipe. The pipe element is constructed in one piece and is produced by a 3D printing process.

To provide a fuel pipe of an aircraft that makes it possible to maintain temperature of fuel in the fuel pipe at appropriate temperature while giving consideration to reliability that is constantly required for the aircraft. A fuel pipe provided in an airframe of the aircraft includes: an inner pipe defining a flow path through which fuel flows; and an outer pipe surrounding an outer periphery of the inner pipe. A gap is provided between the outer periphery of the inner pipe and an inner periphery of the outer pipe. The inner pipe is made of a rubber material, and the outer pipe is made of a metal material.

To provide a fuel pipe of an aircraft that makes it possible to maintain temperature of fuel in the fuel pipe at appropriate temperature while giving consideration to reliability that is constantly required for the aircraft. A fuel pipe provided in an airframe of the aircraft includes: an inner pipe defining a flow path through which fuel flows; and an outer pipe surrounding an outer periphery of the inner pipe. A gap is provided between the outer periphery of the inner pipe and an inner periphery of the outer pipe. The inner pipe is made of a rubber material, and the outer pipe is made of a metal material.

Polymer compositions comprising at least two polyethylene polymers, for example, recycled polymer compositions, methods for the production thereof, the use of functional fillers in said compositions, and articles formed from the polymer compositions. Pipe having at least one wall, the pipe having a nominal inside diameter of at least about 400 mm and a SN of at least about 4, and wherein the at least one wall comprises at least about 25% by weight of recycled polymer, based on the total weight of the at least one wall.

Polymer compositions comprising at least two polyethylene polymers, for example, recycled polymer compositions, methods for the production thereof, the use of functional fillers in said compositions, and articles formed from the polymer compositions. Pipe having at least one wall, the pipe having a nominal inside diameter of at least about 400 mm and a SN of at least about 4, and wherein the at least one wall comprises at least about 25% by weight of recycled polymer, based on the total weight of the at least one wall.

A heating, ventilation, and air-conditioning (HVAC) conduit includes a first HVAC line at least partially nested within a second HVAC line having a configuration defining a U- or C-shaped receiver in cross-section. The first HVAC line is fabricated of a first material and the second HVAC line is fabricated of a second material that is different from the first material.

A flowpath assembly has a first conduit defining a flowpath radially inward, and a second conduit spaced radially outward from the first conduit. A void defined between the first and second conduits contains an insulating material that may have a greater porosity than the first and second conduits. The assembly may be additive manufactured generally as one unitary piece with the raw material of the conduits being melted and solidified on a slice-by-slice basis and the insulating material being selectively bypassed by an energy gun of an additive manufacturing system.

A flowpath assembly has a first conduit defining a flowpath radially inward, and a second conduit spaced radially outward from the first conduit. A void defined between the first and second conduits contains an insulating material that may have a greater porosity than the first and second conduits. The assembly may be additive manufactured generally as one unitary piece with the raw material of the conduits being melted and solidified on a slice-by-slice basis and the insulating material being selectively bypassed by an energy gun of an additive manufacturing system.

The present double walled grease duct includes a tubular outer shell surrounding a tubular inner liner, wherein a spacer is positioned perpendicular to the walls of the outer shell and the inner liner. The spacer can include a plurality of vertical metal strips extend from a top edge of the spacer to the bottom edge of the spacer, wherein the top edge of the spacer contacts the walls of the outer shell and wherein the bottom edge of the spacer contacts the walls of the inner liner. The metal strips resist the different rates of thermal expansion between the outer shell and inner liner ultimately preventing the collapse of the inner liner under pressure from thermal expansion.

The present double walled grease duct includes a tubular outer shell surrounding a tubular inner liner, wherein a spacer is positioned perpendicular to the walls of the outer shell and the inner liner. The spacer can include a plurality of vertical metal strips extend from a top edge of the spacer to the bottom edge of the spacer, wherein the top edge of the spacer contacts the walls of the outer shell and wherein the bottom edge of the spacer contacts the walls of the inner liner. The metal strips resist the different rates of thermal expansion between the outer shell and inner liner ultimately preventing the collapse of the inner liner under pressure from thermal expansion.